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Papers on end-Permian mass extinction and climate

Posted by Ari Jokimäki on January 12, 2012

This is a list of papers that discuss the role of climate in end-Permian mass extinction. The list is not complete, and will most likely be updated in future in order to make it more thorough and more representative.

Calibrating the End-Permian Mass Extinction – Shen et al. (2011) “The end-Permian mass extinction was the most severe biodiversity crisis in Earth history. To better constrain the timing, and ultimately the causes of this event, we collected a suite of geochronologic, isotopic, and biostratigraphic data on several well-preserved sedimentary sections in South China. High-precision U-Pb dating reveals that the extinction peak occurred just before 252.28 ± 0.08 million years ago, after a decline of 2 per mil (‰) in δ13C over 90,000 years, and coincided with a δ13C excursion of −5‰ that is estimated to have lasted ≤20,000 years. The extinction interval was less than 200,000 years and synchronous in marine and terrestrial realms; associated charcoal-rich and soot-bearing layers indicate widespread wildfires on land. A massive release of thermogenic carbon dioxide and/or methane may have caused the catastrophic extinction.” Shu-zhong Shen, James L. Crowley, Yue Wang, Samuel A. Bowring, Douglas H. Erwin, Peter M. Sadler, Chang-qun Cao, Daniel H. Rothman, Charles M. Henderson, Jahandar Ramezani, Hua Zhang, Yanan Shen, Xiang-dong Wang, Wei Wang, Lin Mu, Wen-zhong Li, Yue-gang Tang, Xiao-lei Liu, Lu-jun Liu, Yong Zeng, Yao-fa Jiang, Yu-gan Jin, Science 9 December 2011: Vol. 334 no. 6061 pp. 1367-1372, DOI: 10.1126/science.1213454.

Carbon-isotope stratigraphy across the Permian–Triassic boundary: A review – Korte & Kozur (2010) “The Palaeozoic–Mesozoic transition is marked by distinct perturbations in the global carbon cycle resulting in a prominent negative carbon-isotope excursion at the Permian–Triassic (P–T) boundary, well known from a plethora of marine and continental sediments. Potential causes for this negative δ13C trend (and their links to the latest Permian mass extinction) have been intensively debated in the literature. In order to draw conclusions regarding causation, a general δ13C curve was defined after consideration of all available datasets and with due reference to the biostratigraphic background. The most important features of the P–T carbon-isotope trend are the following: the 4–7‰ δ13C decline (lasting ∼500,000 years) is gradual and began in the Changhsingian at the stratigraphic level of the C. bachmanni Zone. The decreasing trend is interrupted by a short-term positive event that starts at about the latest Permian low-latitude marine main extinction event horizon (=EH), indicating that the extinction itself cannot have caused the negative carbon-isotope excursion. After this short-term positive excursion, the δ13C decline continues to a first minimum at about the P–T boundary. A subsequent slight increase is followed by a second (occasionally two-peaked) minimum in the lower (and middle) I. isarcica Zone. The negative carbon-isotope excursion was most likely a consequence of a combination of different causes that may include: (1) direct and indirect effects of the Siberian Trap and contemporaneous volcanism and (2) anoxic deep waters occasionally reaching very shallow sea levels. A sudden release of isotopically light methane from oceanic sediment piles or permafrost soils as a source for the negative carbon-isotope trend is questionable at least for the time span a little below the EH and somewhat above the P–T boundary.” Christoph Korte, Heinz W. Kozur, Journal of Asian Earth Sciences, Volume 39, Issue 4, 9 September 2010, Pages 215-235, doi:10.1016/j.jseaes.2010.01.005.

Massive volcanism at the Permian–Triassic boundary and its impact on the isotopic composition of the ocean and atmosphere – Korte et al. (2010) “Bulk carbonate and conodonts from three Permian–Triassic (P–T) boundary sections at Guryul Ravine (Kashmir), Abadeh (central Iran) and Pufels/Bula/Bulla (Italy) were investigated for δ13C and δ18O. Carbon isotope data highlight environmental changes across the P–T boundary and show the following features: (1) a gradual decrease of ∼4‰ to more than 7‰ starting in the Late Permian (Changhsingian) C. bachmanni Zone, with two superimposed transient positive excursions in the C. meishanensis–H. praeparvus and the M. ultima–S. ? mostleri Zones; (2) two δ13C minima, the first at the P–T boundary and a higher, occasionally double-minimum in the lower I. isarcica Zone. It is unlikely that the short-lived phenomena, such as a breakdown in biological productivity due to catastrophic mass extinction, a sudden release of oceanic methane hydrates or meteorite impact(s), could have been the main control on the latest Permian carbon isotope curve because of its prolonged (0.5 Ma) duration, gradual decrease and the existence of a >1‰ positive shift at the main extinction horizon. The P–T boundary δ13C trend matches in time and magnitude the eruption of the Siberian Traps and other contemporaneous volcanism, suggesting that volcanogenic effects, such as outgassed CO2 from volcanism and, even more, thermal metamorphism of organic-rich sediments, as the likely cause of the negative trend.” Christoph Korte, Prabhas Pande, P. Kalia, Heinz W. Kozur, Michael M. Joachimski, Hedi Oberhänsli, Journal of Asian Earth Sciences, Volume 37, Issue 4, 1 March 2010, Pages 293-311, doi:10.1016/j.jseaes.2009.08.012.

Illawarra Reversal: The fingerprint of a superplume that triggered Pangean breakup and the end-Guadalupian (Permian) mass extinction – Isozaki (2009) “The Permian magnetostratigraphic record demonstrates that a remarkable change in geomagnetism occurred in the Late Guadalupian (Middle Permian; ca. 265 Ma) from the long-term stable Kiaman Reverse Superchron (throughout the Late Carboniferous and Early-Middle Permian) to the Permian–Triassic Mixed Superchron with frequent polarity changes (in the Late Permian and Triassic). This unique episode called the Illawarra Reversal probably reflects a significant change in the geodynamo in the outer core of the planet after a 50 million years of stable geomagnetism. The Illawarra Reversal was likely led by the appearance of a thermal instability at the 2900 km-deep core–mantle boundary in connection with mantle superplume activity. The Illawarra Reversal and the Guadalupian–Lopingian boundary event record the significant transition processes from the Paleozoic to Mesozoic–Modern world. One of the major global environmental changes in the Phanerozoic occurred almost simultaneously in the latest Guadalupian, as recorded in 1) mass extinction, 2) ocean redox change, 3) sharp isotopic excursions (C and Sr), 4) sea-level drop, and 5) plume-related volcanism. In addition to the claimed possible links between the above-listed environmental changes and mantle superplume activity, I propose here an extra explanation that a change in the core’s geodynamo may have played an important role in determining the course of the Earth’s surface climate and biotic extinction/evolution. When a superplume is launched from the core–mantle boundary, the resultant thermal instability makes the geodynamo’s dipole of the outer core unstable, and lowers the geomagnetic intensity. Being modulated by the geo- and heliomagnetism, the galactic cosmic ray flux into the Earth’s atmosphere changes with time. The more cosmic rays penetrate through the atmosphere, the more clouds develop to increase the albedo, thus enhancing cooling of the Earth’s surface. The Illawarra Reversal, the Kamura cooling event, and other unique geologic phenomena in the Late Guadalupian are all concordantly explained as consequences of the superplume activity that initially triggered the breakup of Pangea. The secular change in cosmic radiation may explain not only the extinction-related global climatic changes in the end-Guadalupian but also the long-term global warming/cooling trend in Earth’s history in terms of cloud coverage over the planet.” Yukio Isozaki, Gondwana Research, Volume 15, Issues 3-4, June 2009, Pages 421-432, Special Issue: Supercontinent Dynamics, doi:10.1016/j.gr.2008.12.007.

Elevated atmospheric CO2 and the delayed biotic recovery from the end-Permian mass extinction – Fraiser & Bottjer (2007) “Excessive CO2 in the Earth ocean–atmosphere system may have been a significant factor in causing the end-Permian mass extinction. CO2 injected into the atmosphere by the Siberian Traps has been postulated as a major factor leading to the end-Permian mass extinction by facilitating global warming, widespread ocean stratification, and development of anoxic, euxinic and CO2-rich deep waters. A broad incursion of this toxic deep water into the surface ocean may have caused this mass extinction. Although previous studies of the role of excessive CO2 have focused on these “bottom-up” effects emanating from the deep ocean, “top-down” effects of increasing atmosphere CO2 concentrations on ocean-surface waters and biota have not previously been explored. Passive diffusion of atmospheric CO2 into ocean-surface waters decreases the pH and CaCO3 saturation state of seawater, causing a physiological and biocalcification crisis for many marine invertebrates. While both “bottom-up” and “top-down” mechanisms may have contributed to the relatively short-term biotic devastation of the end-Permian mass extinction, such a “top-down” physiological and biocalcification crisis would have had long-term effects and might have contributed to the protracted 5- to 6-million-year-long delay in biotic recovery following this mass extinction. Earth’s Modern marine biota may experience similar “top-down” CO2 stresses if anthropogenic input of atmosphere/ocean CO2 continues to rise.” Margaret L. Fraiser, David J. Bottjer, Palaeogeography, Palaeoclimatology, Palaeoecology, Volume 252, Issues 1-2, 20 August 2007, Pages 164-175, The Permian-Triassic Boundary Crisis and Early Triassic Biotic Recovery, doi:10.1016/j.palaeo.2006.11.041.

Paleophysiology and end-Permian mass extinction – Knoll et al. (2007) “Physiological research aimed at understanding current global change provides a basis for evaluating selective survivorship associated with Permo-Triassic mass extinction. Comparative physiology links paleontological and paleoenvironmental observations, supporting the hypothesis that an end-Permian trigger, most likely Siberian Trap volcanism, touched off a set of physically-linked perturbations that acted synergistically to disrupt the metabolisms of latest Permian organisms. Global warming, anoxia, and toxic sulfide probably all contributed to end-Permian mass mortality, but hypercapnia (physiological effects of elevated PCO2) best accounts for the selective survival of marine invertebrates. Paleophysiological perspectives further suggest that persistent or recurring hypercapnia/global warmth also played a principal role in delayed Triassic recovery. More generally, physiology provides an important way of paleobiological knowing in the age of Earth system science.” Andrew H. Knoll, Richard K. Bambach, Jonathan L. Payne, Sara Pruss, Woodward W. Fischer, Earth and Planetary Science Letters, Volume 256, Issues 3-4, 30 April 2007, Pages 295-313, doi:10.1016/j.epsl.2007.02.018. [Full text]

End-Permian mass extinction pattern in the northern peri-Gondwanan region – Shen et al. (2007) “The Permian-Triassic extinction pattern in the peri-Gondwanan region is documented biostratigraphically, geochemically and sedimentologically based on three marine sequences deposited in southern Tibet and comparisons with the sections in the Salt Range, Pakistan and Kashmir. Results of biostratigraphical ranges for the marine faunas reveal an end-Permian event comparable in timing with that known at the Meishan section in low palaeolatitude as well as Spitsbergen and East Greenland in northern Boreal settings although biotic patterns earlier in the Permian vary. The previously interpreted delayed extinction (Late Griesbachian) at the Selong Xishan section is not supported by our analysis. The end-Permian event exhibits an abrupt marine faunal shift slightly beneath the Permian-Triassic boundary (PTB) from benthic taxa- to nektic taxa-dominated communities. The climate along the continental margin of Neo-Tethys was cold before the extinction event. However, a rapid climatic warming event as indicated by the southward invasion of abundant warm-water conodonts, warm-water brachiopods, calcareous sponges, and gastropods was associated with the extinction event. Stable isotopic values of δ13Ccarb, δ13Corg and δ18O show a sharp negative drop slightly before and during the extinction interval. Sedimentological and microstratigraphical analysis reveals a Late Permian regression, as marked by a Caliche Bed at the Selong Xishan section and the micaceous siltstone in the topmost part of the Qubuerga Formation at the Qubu and Tulong sections. The regression was immediately followed by a rapid transgression beneath the PTB. The basal Triassic rocks fine upward, and are dominated by dolomitic packstone/wackestone containing pyritic cubes, bioturbation and numerous tiny foraminifers, suggesting that the studied sections were deposited during the initial stage of the transgression and hence may not have been deeply affected by the anoxic event that is widely believed to characterise the zenith of the transgression.” Shu Zhong Shen, Chang-Qun Cao, Charles M. Henderson, Xiang-Dong Wang, Guang R. Shi, Yue Wang, Wei Wang, Palaeoworld, Volume 15, Issue 1, January 2006, Pages 3-30, doi:10.1016/j.palwor.2006.03.005. [Full text]

Middle-Late Permian mass extinction on land – Retallack et al. (2006) “The end-Permian mass extinction has been envisaged as the nadir of biodiversity decline due to increasing volcanic gas emissions over some 9 million years. We propose a different tempo and mechanism of extinction because we recognize two separate but geologically abrupt mass extinctions on land, one terminating the Middle Permian (Guadalupian) at 260.4 Ma and a later one ending the Permian Period at 251 Ma. Our evidence comes from new paleobotanical, paleopedological, and carbon isotopic studies of Portal Mountain, Antarctica, and comparable studies in the Karoo Basin, South Africa. Extinctions have long been apparent among marine invertebrates at both the end of the Guadalupian and end of the Permian, which were also times of warm-wet greenhouse climatic transients, marked soil erosion, transition from high- to low-sinuosity and braided streams, soil stagnation in wetlands, and profound negative carbon isotope anomalies. Both mass extinctions may have resulted from catastrophic methane outbursts to the atmosphere from coal intruded by feeder dikes to flood basalts, such as the end-Guadalupian Emeishan Basalt and end-Permian Siberian Traps.” Gregory J. Retallack, Christine A. Metzger, Tara Greaver, A. Hope Jahren, Roger M.H. Smith and Nathan D. Sheldon, GSA Bulletin, v. 118 no. 11-12 p. 1398-1411, doi: 10.1130/B26011.1. [Full text]

Climate simulation of the latest Permian: Implications for mass extinction – Kiehl & Shields (2005) “Life at the Permian-Triassic boundary (ca. 251 Ma) underwent the largest disruption in Earth’s history. Paleoclimatic data indicate that Earth was significantly warmer than present and that much of the ocean was anoxic or euxinic for an extended period of time. We present results from the first fully coupled comprehensive climate model using paleogeography for this time period. The coupled climate system model simulates warm high-latitude surface air temperatures related to elevated carbon dioxide levels and a stagnate global ocean circulation in concert with paleodata indicating low oxygen levels at ocean depth. This is the first climate simulation that captures these observed features of this time period.” Jeffrey T. Kiehl and Christine A. Shields, Geology, v. 33 no. 9 p. 757-760, doi: 10.1130/G21654.1. [Full text]

How to kill (almost) all life: the end-Permian extinction event – Benton & Twitchett (2003) “The biggest mass extinction of the past 600 million years (My), the end-Permian event (251 My ago), witnessed the loss of as much as 95% of all species on Earth. Key questions for biologists concern what combination of environmental changes could possibly have had such a devastating effect, the scale and pattern of species loss, and the nature of the recovery. New studies on dating the event, contemporary volcanic activity, and the anatomy of the environmental crisis have changed our perspectives dramatically in the past five years. Evidence on causation is equivocal, with support for either an asteroid impact or mass volcanism, but the latter seems most probable. The extinction model involves global warming by 6°C and huge input of light carbon into the ocean-atmosphere system from the eruptions, but especially from gas hydrates, leading to an ever-worsening positive-feedback loop, the ‘runaway greenhouse’.” Michael J. Benton, Richard J. Twitchett, Trends in Ecology & Evolution, Volume 18, Issue 7, July 2003, Pages 358-365, doi:10.1016/S0169-5347(03)00093-4. [Full text]

Land-plant diversity and the end-Permian mass extinction – Rees (2002) “The Permian and Triassic represent a time of major global climate change from icehouse to hothouse conditions and significant (∼25°) northward motion of landmasses amalgamated in essentially one supercontinent, Pangea. The greatest of all mass extinctions occurred around the Permian-Triassic boundary (251 Ma), although there is no consensus regarding the cause(s). Recent studies have suggested a meteor impact and worldwide die-off of vegetation, on the basis of sparse local observations. However, new analyses of global Permian and Triassic plant data in a paleogeographic context show that the scale and timing of effects varied markedly between regions. The patterns are best explained by differences in geography, climate, and fossil preservation, not by catastrophic events. Caution should be exercised when extrapolating local observations to global-scale interpretations. At the other extreme, global compilations of biotic change through time can be misleading if the effects of geography, climate, and preservation bias are not considered.” P. McAllister Rees, Geology, v. 30 no. 9 p. 827-830, doi: 10.1130/0091-7613(2002)​030​2.0.CO;2. [Full text]

Ocean stagnation and end-Permian anoxia – Hotinski et al. (2001) “Ocean stagnation has been invoked to explain the widespread occurrence of organic-carbon–rich, laminated sediments interpreted to have been deposited under anoxic bottom waters at the time of the end-Permian mass extinction. However, to a first approximation, stagnation would severely reduce the upwelling supply of nutrients to the photic zone, reducing productivity. Moreover, it is not obvious that ocean stagnation can be achieved. Numerical experiments performed with a three-dimensional global ocean model linked to a biogeochemical model of phosphate and oxygen cycling indicate that a low equator to pole temperature gradient could have produced weak oceanic circulation and widespread anoxia in the Late Permian ocean. We find that polar warming and tropical cooling of sea-surface temperatures cause anoxia throughout the deep ocean as a result of both lower dissolved oxygen in bottom source waters and increased nutrient utilization. Buildup of quantities of H2S and CO2 in the Late Permian ocean sufficient to directly cause a mass extinction, however, would have required large increases in the oceanic nutrient inventory.” Roberta M. Hotinski, Karen L. Bice, Lee R. Kump, Raymond G. Najjar and Michael A. Arthur, Geology, v. 29 no. 1 p. 7-10, doi: 10.1130/0091-7613(2001)​029​2.0.CO;2. [Full text]

Pattern of Marine Mass Extinction Near the Permian-Triassic Boundary in South China – Jin et al. (2000) “The Meishan section across the Permian-Triassic boundary in South China is the most thoroughly investigated in the world. A statistical analysis of the occurrences of 162 genera and 333 species confirms a sudden extinction event at 251.4 million years ago, coincident with a dramatic depletion of δ13Ccarbonate and an increase in microspherules.” Y. G. Jin, Y. Wang, W. Wang, Q. H. Shang, C. Q. Cao and D. H. Erwin, Science 21 July 2000: Vol. 289 no. 5478 pp. 432-436, DOI: 10.1126/science.289.5478.432. [Full text]

U/Pb Zircon Geochronology and Tempo of the End-Permian Mass Extinction – Bowring et al. (1998) “The mass extinction at the end of the Permian was the most profound in the history of life. Fundamental to understanding its cause is determining the tempo and duration of the extinction. Uranium/lead zircon data from Late Permian and Early Triassic rocks from south China place the Permian-Triassic boundary at 251.4 ± 0.3 million years ago. Biostratigraphic controls from strata intercalated with ash beds below the boundary indicate that the Changhsingian pulse of the end-Permian extinction, corresponding to the disappearance of about 85 percent of marine species, lasted less than 1 million years. At Meishan, a negative excursion in δ13C at the boundary had a duration of 165,000 years or less, suggesting a catastrophic addition of light carbon.” S. A. Bowring, D. H. Erwin, Y. G. Jin, M. W. Martin, K. Davidek and W. Wang, Science 15 May 1998: Vol. 280 no. 5366 pp. 1039-1045, DOI: 10.1126/science.280.5366.1039.

Oceanic Anoxia and the End Permian Mass Extinction – Wignall & Twitchett (1996) “Data on rocks from Spitsbergen and the equatorial sections of Italy and Slovenia indicate that the world’s oceans became anoxic at both low and high paleolatitudes in the Late Permian. Such conditions may have been responsible for the mass extinction at this time. This event affected a wide range of shelf depths and extended into shallow water well above the storm wave base.” Paul B. Wignall, Richard J. Twitchett, Science 24 May 1996: Vol. 272 no. 5265 pp. 1155-1158, DOI: 10.1126/science.272.5265.1155.

Comparative Earth History and Late Permian Mass Extinction – Knoll et al. (1996) “The repeated association during the late Neoproterozoic Era of large carbon-isotopic excursions, continental glaciation, and stratigraphically anomalous carbonate precipitation provides a framework for interpreting the reprise of these conditions on the Late Permian Earth. A paleoceanographic model that was developed to explain these stratigraphically linked phenomena suggests that the overturn of anoxic deep oceans during the Late Permian introduced high concentrations of carbon dioxide into surficial environments. The predicted physiological and climatic consequences for marine and terrestrial organisms are in good accord with the observed timing and selectivity of Late Permian mass extinction.” A. H. Knoll, R. K. Bambach, D. E. Canfield, J. P. Grotzinger, Science 26 July 1996: Vol. 273 no. 5274 pp. 452-457, DOI: 10.1126/science.273.5274.452.

Synchrony and Causal Relations Between Permian-Triassic Boundary Crises and Siberian Flood Volcanism – Renne et al. (1995) “The Permian-Triassic boundary records the most severe mass extinctions in Earth’s history. Siberian flood volcanism, the most profuse known such subaerial event, produced 2 million to 3 million cubic kilometers of volcanic ejecta in approximately 1 million years or less. Analysis of 40Ar/39Ar data from two tuffs in southern China yielded a date of 250.0 ± 0.2 million years ago for the Permian-Triassic boundary, which is comparable to the inception of main stage Siberian flood volcanism at 250.0 ± 0.3 million years ago. Volcanogenic sulfate aerosols and the dynamic effects of the Siberian plume likely contributed to environmental extrema that led to the mass extinctions.” Paul R. Renne, Michael T. Black, Zhang Zichao, Mark A. Richards and Asish R. Basu, Science 8 September 1995: Vol. 269 no. 5229 pp. 1413-1416, DOI: 10.1126/science.269.5229.1413. [Full text]

Synchronism of the Siberian Traps and the Permian-Triassic Boundary – Campbell et al. (1992) “Uranium-lead ages from an ion probe were taken for zircons from the ore-bearing Noril’sk I intrusion that is comagmatic with, and intrusive to, the Siberian Traps. These values match, within an experimental error of ±4 million years, the dates for zircons extracted from a tuff at the Permian-Triassic (P-Tr) boundary. The results are consistent with the hypothesis that the P-Tr extinction was caused by the Siberian basaltic flood volcanism. It is likely that the eruption of these magmas was accompanied by the injection of large amounts of sulfur dioxide into the upper atmosphere, which may have led to global cooling and to expansion of the polar ice cap. The P-Tr extinction event may have been caused by a combination of acid rain and global cooling as well as rapid and extreme changes in sea level resulting from expansion of the polar ice cap.” I. H. Campbell, G. K. Czamanske, V. A. Fedorenko, R. I. Hill and V. Stepanov, Science 11 December 1992: Vol. 258 no. 5089 pp. 1760-1763, DOI: 10.1126/science.258.5089.1760.

The End-Permian mass extinction: What really happened and did it matter? – Erwin (1989) “Marine communities of the Paleozoic differ markedly from those of the post-Paleozoic, a dichotomy long recognized as the most fundamental change between the Cambrian metazoan radiation and the present. The end-Permian mass extinction of about 54% of marine families eliminated many of the groups that dominated Paleozoic communities. Correlative changes occurred in terrestrial vertebrate and plant communities, but there is no clear evidence that these changes are related to the marine extinction. The marine extinction occurred during a period of physical change, and a variety of extinction mechanisms have been proposed, most related to a major Late Permian marine regression or to climatic changes. Unfortunately, the regression has made it difficult to gather data on the rate, timing and pattern of extinction, and the available data exclude only a few hypotheses. Thus the largest mass extinction, and the one with the greatest evolutionary importance, is also the most poorly understood.” Douglas H. Erwin, Trends in Ecology & Evolution, Volume 4, Issue 8, August 1989, Pages 225–229, http://dx.doi.org/10.1016/0169-5347(89)90165-1.

8 Responses to “Papers on end-Permian mass extinction and climate”

  1. Mr. Jokimaki; 250 million years ago, was no sufficient vegetation to create the methane, for a start. b] thanks to the fossil fuel in the ground – there is abundant amount of free oxygen in the atmosphere for fire. Not just the oxygen from the CO2 molecule; but the oxygen from the water molecules that created the fossil fuel, oxygen that is now up in the atmosphere and in the water as free agent O2.

    Extensive fires were impossible then, due to lack of free oxygen and tremendous amount of CO2 as fire retardant molecule. The shear number of those shonky ”researchers” should tell you that: they make up a theory > then they make up things to fit their theory. When the collapse of Pangea happened – there was prolific algae population – their mas was converted into CO2 again by the fungi.

    You people keep confusing the the different carbon and oxygen isotopes; somehow to snick in the phony GLOBAL warmings. At that time the set-up was completely different. First of all, there was NO fossil fuel in the ground. Which means, with oxygen at a very low percent in the air, ALL the oxygen you talk about was in CO2, FeO, H2O molecules. Methane in the ground is the most widely distributed now, but being in presence of coal and crude oil; clearly states that methane is not a leftover from the primordial planet, but was created at much lighter date. Between the falling apart of Pangea and Gondwanaland was no fossil fuel. Only ”free” oxygen that wasn’t any-more in molecular form was produced ONLY by the corals and shells.

    I think it’s time for you to stop making connections / similarity with anything that happened before 50 million years ago, with the IPCC’s phony GLOBAL warming.

  2. Ari Jokimäki said

    You make lot of claims, but don’t back up any of them with proper references. I also think you should stop throwing insults at people (such as researchers), if you wish to continue making posts here.

    Global warming, by the way, was discussed in scientific literature way before IPCC started. As you call it “phony”, do you deny that there has been global warming in recent decades?

  3. Ari, in one paragraph is impossible to fit the 1000 proofs I have. 2] I have proven ”beyond any reasonable doubt, that wasn’t any GLOBAL warmings” all the warmings are localized – NEVER global; because the laws of physics don’t permit that! 3] even in ”hypothetical” pretend that extra warming happen – they cannot record it. Because: unlike on the moon, on the earth, heat distribution is 3 dimensional – it’s ESSENTIAL to have evenly distributed 500 monitoring places on every cubic kilometre of troposphere; plus because in fluctuation of strength of winds; to be taken temperature for EVERY 10-15 minutes.

    [AGW Observer note: insulting comments deleted from this post.]

  4. Ari Jokimäki said

    Stefanthedenier, you continued to make insulting remarks about researchers. I have removed those remarks from your post above. I will not allow comments like that here. If you want to pour trash over climate scientists, there are plenty of websites all over the Internet that allow this. I don’t. This is a last warning to you. Do that again and you won’t post here anymore.

    You refuse to give proofs to your claims. Without proofs you haven’t given us anything else but empty claims. I’m sure that it should be easy to show (with proper references) in one paragraph that there were no sufficient vegetation to create methane 250 million years ago. If you claim that as a fact, then it should be easy to show this (no 1000 proofs are needed here). If you can do that, you would also need to show that methane cannot originate from anything else than vegetation.

  5. Ari Jokimäki said

    Stefanthedenier made another post trying to continue with the same style without slightest effort to compromise, so he is not allowed to post here anymore.

    I will be posting rules for discussion in near future.

  6. Are there any studies done about methane excursions and the ozone layer?

    For instance http://climateforce.net/2012/01/24/long-lived-cfcs-methane-nitrous-oxide-uptake-and-the-destruction-of-the-northern-hemisphere-ozone-layer/

  7. Ari Jokimäki said

    This rather old review paper touches the issue of methane and ozone depletion. Here is an example of more recent paper. There seems to be quite a lot of studies on this issue, many of them are general ozone depletion studies that discuss this issue among others.

  8. Because of your interest in the Permian and Triassic, you may find interesting a series of articles that discuss the possible large impact that development of the ability to digest cellulose by roaches and prototermites may have had on Permian ecology, climate, glaciers, and on the Triassic coal hiatus, Triassic 12% oxygen, and climate shown in http://www.angelfire.com/nc/isoptera/roach.html . The following end Permian extinctions are discussed in http://www.angelfire.com/nc/isoptera/permian.html If you see any errors in them or possible additions, please let me know. Sincerely, Charles Weber DID the WOOD ROACH CAUSE the PERMIAN ARIDITY, RED BEDS, and CONIFER RISE? by Charles Weber Cellulose digestion by wood roaches may have removed enough mulch (detritus) to have caused hiatus of coal, aridity, and some of the temperature rise, as well as increasing conifers in late Permian. The largest part of the temperature rise may have been from overturn of an anoxic ocean by a huge comet. ABSTRACT It is suggested that the symbiosis of cellulose digesting microbes with the cockroach, probably in the Permian, caused fundamental ecological changes which lowered soil organic matter, created aridity, helped increase atmospheric carbon dioxide, helped eliminate glaciers, and favored conifers with their inert interior and wood poisons. In the form of prototermites with a soldier caste, it is suggested that they spread the conifers in early Triassic, caused the early Triassic coal hiatus, and possibly contributed to extinctions at the close of the Permian when dropping sea levels permitted them to spread around the world, the last possibly from the indirect effects of a comet impact coupled to filling of below sea level depressions. INTRODUCTION Living things in the present day display enormous diversity. Many strategies have evolved, especially on land. A large number of plant and animal poisons have appeared. There are several dozen fundamentally different reproductive strategies. Animal and plant sizes are spread over ratios which are billions to one. Numerous ingenious feeding and poison delivery systems have evolved. It is difficult for us living with these current events, which prevent any animal or plant from acquiring an overwhelming advantage, to conceive of a simpler world in which even small changes could have dramatic widespread effects on the ecology and environment. The Permian was a time when many of the basic attributes that we see today first evolved. This article will attempt to explore the effects, which a symbiosis of cellulose digesting microbes with an ancient roach had on the world, probably starting in the Permian. However this, of course, was not a small change. It was as if the vast stores of cellulose in the world had suddenly turned to sugar. There is also a difficulty to perceive that rates of evolution must proceed at drastically different rates. A simple change such as change in size or loss of an existing organ should be able to occur with crisp speed, as we have seen with domesticated organisms. On the other hand, complicated neural patterns such as nest building and intricate organs such as termite poison squirting apparatus must surely require long periods of time. Progenitors of traits like these must surely go back a considerable span from when they first appear on the fossil record, especially when associated with a long lived or sparsely populated organism or when a sudden appearance of diverse forms imply an undiscovered source. DISCUSSION Soil Organic Matter Sometime in the vicinity of the Cambrian period multicelled plants evolved which could synthesize cellulose and live on dry land [Axelrod, 1969]. This, unlike animals, is believed to have happened only once [Kenrik and Crane 1997]. The advantage cellulose gave them was tremendous. Cellulose is a long chain carbohydrate polymer derived from sugar. Not only are there very few organisms which can break the cellulose linkages, but even those which can, do so slowly, because enormously large molecules can form. Its tensile strength is very great, and therefore large stemmed plants were made possible for competition for light. Hydrogen bonding of the polymer chains allowed for considerable shock stress before rupture which prevented brittle fracture in high wind or animal blows. Also important was its lack of palatability and indigestibility to the primitive worms, millipedes, snails and other animals which came out on land then or soon after. As a result, descendants of these plants spread across the land in the form of forests of ferns and other plants by the Devonian. These forests resulted in thin coal seams, which became thicker as the carboniferous went on. One reason why thick coal deposits were able to form was that those early plants made extensive use of lignin. They had bark to wood ratios of 8 to 1, and even as high as 20 to 1. This compares to modern values less than 1 to 4. This bark, which must have been used as support as well as protection, probably had 38% to 58% lignin [Robinson p608]. Lignin is insoluble, too large to pass through cell walls, too heterogeneous for specific enzymes, and toxic, so that few organisms other than Basidiomycetes funguses can degrade it. It can not be oxidized in less than 5% oxygen atmosphere. It can linger in soil for thousands of years and inhibits decay of other substances [Robinson p608]. Probably the reason for its high percentages is protection from insect herbivory in a world containing very effective herbivores, but nothing remotely as effective as modern insectivores and probably much fewer poisons than currently. Roaches It was not until the Carboniferous that large numbers of insects appeared on the fossil record. It is thought that they may have evolved on some as yet unknown island from worm like ancestors similar to the caterpillar like Onychophora, and then became inoculated fully developed into the known continents. Primitive silver fish, collembola, and dragonflies became numerous. The Insect orders became the most important of the herbivorous orders. By the Pennsylvanian, by far the most successful were ancestors of the cockroach. Six fast legs, two well developed folding wings, fairly good eyes, long, well developed antennae (olfactory), an omnivorous digestive system, a receptacle for storing sperm, a chitin skeleton that could support, protect, as well as form a gizzard, and efficient mouth parts gave it formidable advantages over other herbivorous animals. Present day roaches can eat bark, leaves, pith of living cycads, paper, wool, sugar, cheese bread, oil, lemon, flesh, fish, leather, dead roaches [Miall], and earth [author’s observation]. About 90% of insects were roaches [Zimmerman,]. The Pennsylvanian is sometimes known as the age of roaches. Especially significant was their ability to lay their eggs on dry land. The excretion of nitrogen in the form of insoluble uric acid is said to be an important factor in their successful invasion of dry land. [Prosser et al, 1950]. Spiders, centipedes, scorpions, and amphibious vertebrates could take a toll on the ground and ancestors of the dragonfly could catch them in the air, but these predators lacked the efficiency of our best modern predators. Catching them, equipped as they were with efficient sensory and locomotive apparatus, may have been something other than easy. Even where the amphibians and dragonflies were numerous, roaches were probably an effective group, for they grew to great size. Their attack on plants must have been severe, and they also must have had an affect on disease transmission. They were the most important part of the fauna until well into the Triassic [Anderson, et al, 1996]. The fast turnover of plant life helped build up the soil organic content. The large roaches probably could not venture out onto twigs, so they probably caused even more leaf fall than what they managed to eat. Bite marks on leaves are rare, less than 4% [Chaloner]. I suspect that their discards and excreta were a considerable part of the thick layers of litter which later turned into coal. Insects were probably the dominant herbivores then [Shear]. Spore ferns, horse tail rushes, and lycopods or club mosses, were the plants present [Gastaldo, with colored graphs]. The Wood Roach Within the moist upper Pennsylvanian or Permian soil there dwelt a ciliated protozoa capable of digesting particles of cellulose and leaves which descended from above in a never ending rain of insect droppings, etc. and converting them into energy. This microorganism lived under anaerobic conditions since its descendants in wood roaches are anaerobic. There are no such organisms known to be living in the soil or swamps today, but they must have existed at one time. Eventually a roach or roaches evolved, which, instead of digesting that protozoa, formed a symbiosis with it. This meant that now for the first time, a higher animal could make use of the vast stores of cellulose which littered the earth and perhaps even much of that incorporated in the plants, especially the trunks of trees. During the Permian plants started to dominate which made use of dead material high in cellulose in their interiors, such as conifers. According to Kirby the use of cellulose by insects took place in the Permian or Triassic [Steinhaus, 1947; p531]. Fossil wings have been discovered in the Permian of Kansas which have a close resemblance to wings of Mastotermes, which is the most primitive living termite and which is thought to be the descendant of Cryptocercus genus, the wood roach. This fossil is called Pycnoblattina. It folded its wings in a convex pattern between segments 1a and 2a. Mastotermes is the only living insect that does the same [Tilyard RJ 1937]. This is strong circumstantial evidence that the wood roach did evolve in the Permian. If the wood roach is the ancestor of Mastotermes, analysis of its mitochondrial ribosomal DNA for RNA genes [Kambhampati 1995], indicate that a large number of descendants are missing from the fossil record. I suspect that it was the primary change which brought, by the end of the Permian, a close to the carboniferous coal deposits, except in Australia [Tilyard, 1917] at least. Cellulose digestion is inefficient and very rare in insects [Martin], and is probably a recent development in the few other species that have it. Not until the third molt does the nymph complete its symbiosis, possibly because of high pH in the gut [Nalepa, 1990]. As a result, wood roaches have a strong imperative to be social in order to transmit the microbes. This symbiosis probably predated sociality because parental care is rare in Blabeoidea to which family the wood roach is said to belong [Grandicolas 1996, p523]. However, Kambhampati places it neither there nor in Polyphaginae subfamily, but more closely related to Blattidae, so he assigns it to its own family, Cryptocecidae. All this last on the basis of mitochondrial DNA testing [Kambhampati 1996]. The Permian was a transition period in the earth’s history. If the wood roach evolved in this period, it did so in a harsh environment. The Pennsylvanian may have been much different in some areas than the damp coal forests would indicate, but the Permian was definitely characterized by widespread aridity and climatic extremes. Indeed, the effects which wood roaches had on soil organic matter may have caused a considerable part of the climatic extremes. Mulch and organic matter permit considerable infiltration of water into soils by virtue of decreased runoff and increased porosity and also are capable of considerable water storage themselves. As a result moisture can be transferred far inland by air moistened by those stores. In addition, the oxidation of these vast stores of carbon must have caused an increase of the greenhouse effect. This could have caused a small part of the increase of carbon dioxide believed to have occurred in the Permian [Mora et al, 1996] [Berner & Canfield, 1991]. It could not have caused a major rise because the oceans have a tremendous capacity to absorb carbon dioxide. It was probably a triggering affect. The ocean contains fifteen times as much carbon as all terrestrial biotic content and sixty tines the atmosphere. [Walker and Drever 1988, p63][Gregor, et al]. This may be the reason why the oxygen started to drop rapidly at mid Permian while the carbon dioxide only started to rise rapidly starting about two thirds through the Permian [Huey and Ward 2005]. I suspect the bulk of the rise was from oxidation of coal exposed by the rise of the Appalachian and Ural Mountains coupled with a lessened withdrawal by marine shellfish (because of phosphorus surfeit to be discussed in a later article). Initially dissolution of the vast deposits of limestone and dolomite may also have contributed, although eventually such dissolution would actually subtract carbon dioxide from the atmosphere because of making the ocean more alkaline, although half the carbon would be released again when shellfish skeletons settled out. The net affect would have increased temperatures especially in high latitudes [Creber & Chaloner, 1985; p47] and therefore evaporation. While increased atmospheric carbon dioxide would increase temperature, in early Permian, the first major rise followed a temperature rise. This would seem to indicate that a rise in temperature permitted cellulose digesting insects to move toward the poles, and thus increase release of carbon dioxide. When there was a drastic decline in carbon dioxide about 5 million years later, the temperature started its main decline about 2 or 3 million years later, and it did not decline to its value it had at an equivalent carbon dioxide value [Montanez]. So evidently, if insects were a large part of this, something besides temperature caused the roach decline. Subsequent changes in carbon dioxide showed no close parallel to temperature either. The detritus removal also would have increased the areas of deserts. The affect was probably accentuated by a positive feed back implied in the release by warming of the huge stores of methane hydrate [Kvenvolden, 1988] in ocean sediments. In any case the southern glaciers around the Indian ocean subsided during the Permian and after they disappeared, glaciers did not reappear extensively for more than another 200 million years. It is difficult to speculate on the organic content of ancient soils. There is always the chance that carbonaceous material is added to or subtracted from the soil after burial, especially subtracted. Color is a poor indication even in modern soils [Vageler, 1947; p7]. However, coal and black soil shales had virtually disappeared from North America by the last of the Permian, and red shales became common.Red shales may have been caused by high alkalinity in the gut of humus eating roaches. Red shales appeared early in the Permian in South Africa and in late Pennsylvanian in North America and in the mid Permian in Europe and Argentina (Veevers p192). They formed below 40 degrees latitude and were associated with evaporates [Frakes p113], so they must have been in what we now call tropical savanna regions. If the red beds were caused by roaches they were not necessarily cellulose digesting species. Toward the end of the Permian coal began to disappear from the tropics and became increasingly located at higher latitudes, unlike the Carboniferous [Erwin, 1993, p165]. This would be understandable if tropical wood roaches were moving toward the poles in a world which was warming up and they were already eating mulch (detritus) and possibly more importantly, reducing productivity by attacking trees at there most vulnerable place, the trunk interiors. It is probable that some of those roaches, which were making use of mulch directly, we would have been tempted to designate termites or prototermites. This is because burrowing into mulch, soil, or logs imposes environments that require thin skin for respiration in a high carbon dioxide atmosphere, and favors loss of pigments and eyes. Also modern wood roaches are devoid of wings [Srinivas et al., 1996] and the most numerous species of humus eaters may have been so devoid then. Since they probably rarely or never flew or even emerged from their tunnels they would not have been likely to leave many fossils. However, their prototypes probably did leave fossils. Tilyard believes that Pycnoblattina genus of the Pyknoblattinae subfamily fossils from lower Permian Kansas are very similar to Mastotermes and are either an ancestor or sister group, as already mentioned. He bases this observation on the fact that the wing hinge of the rear wing is in the same location as Mastotermes and is found on no other modern insect (Tilyard 1937, p171 & 266). Most of the fossils are forewings. This may be because of the nature of Arachnid predation [[Duncan et al 2003]. There are no soft body parts known yet, but the pronotum head covering is similar in both genera also. There are a few fossil hard head parts which also bear some resemblance to Mastotermes.(Tilyard, p274), and other aspects of wing venation have many points of similarity. Termites may have evolved from one of the forms similar to wood roaches roaches and acquired their symbiosis from wood roaches. Gene sequences for 18s mitochondrial cytochrome oxidase subunit II and endogenous endo-beta-1, 4-glucanase indicates termites and wood roaches are in the same clade [Lo]. So it is fitting that we describe one of the two known survivors as reported by Cleveland [Cleveland et al., 1934]. The name of this roach is Cryptocercus punctulatus. It manages to exist in a narrow belt in the temperate regions where the winters are not too severe. It has no wings, is about 2.5 centimeters long, and manages to subsist in small colonies inside rotten logs. It still retains most of the roach features, but it bears some resemblance to termites. Its nymphs are not pigmented. The mouth parts are very similar to worker termites. Strangely enough it has a peculiar jerky motion at certain times, which some termites use. Its courtship is similar to termites and it mates before, during, and after it lays eggs [Nalepa, 1988]. Most fundamental of all is the close similarity of the digestive system to that of termites, including a symbiosis with cellulose digesting protozoa housed in the hind gut which are lost after each molt. It has a primitive social structure, required for transmittal of its protozoa after a molt. All these facts constitute circumstantial evidence that this insect is closely related to the ancestor of the termites. However it does not leave any additional clues as to the importance of its progenitors in ancient ages. For this, a look at its protozoan population is instructive. Its hind intestine contains nine genera of Hypermastigina class, one of which is known from termites, and three genera from the more primitive Polymastigina, two of which are known in termites. A single species of termites is not found to have a random protozoa population in nature and does not vary [Steinhaus, 1947; p531]. If ancient roaches interchanged protozoa with equal difficulty, it implies evolution of a numerous population for a considerable time until displaced by termites. There has been an interchange affected in the laboratory, though. Nevertheless, at first glance it would seem that this roach might represent the survivor of a once much more numerous family of insects which remained so for a long time. The wood roach has a more complicated digestive system than termites, which would seem to be further indication of this possibility. Of course termites could have evolved from non symbiotic sister group of wood roaches long after the wood roaches we know, by transfer of the protozoa, and this could have diversified rapidly long after wood roaches had first appeared. Nalepa and Thorne disagree as to the likelyhood of the transfer of symbionts between termites and roaches in the past [Thorne][Nalepa, 1991]. However in the course of several hundred million years transfer without a doubt occurred times without number without necessarily taking, so not only is either hypothesis possible but both may be involved on several occasions. The difficulty in this aspect of evolution is not with termite habits or protozoa evolution per se but more likely the nature of the molecules termites must be synthesizing in order to control the protozoa and prevent disease and “weeds”. I doubt if we have enough information to resolve the matter at present. The likelihood that termites themselves are derived from a single ancestral group is especially possible if you define a termite as a roach with a soldier caste. However most digestive features probably existed before the coal hiatus. The Australian wood eating cockroach secretes an enzyme which digests cellulose and is almost devoid of protozoa [Scrivener, et al., 1989]. This must surely be a late development after termite progenitors developed a soldier caste because a symbiosis would not have been necessary if this trait had developed early on. It is conceivable that some of the termites developed from a cousin of this roach and then subsequently some of them lost the enzyme. However it is very unlikely because the most primitive termites lack this enzyme and the soldier caste only evolved once [Rosin, 1994]. Termites which have a cellulose digesting enzyme, such as reticulitermes, produces only small amounts of glucose at the salivary gland [Watanabe & Noda]. Coptotermes and Nasutitermes secrete cellulase only from the salivary gland [Hogan]. Even if such an enzyme existed then in that form (as opposed to being reevolved later), it would not likely have been important or interfered with protozoan evolution. TERMITES Any social roach which bored into the soil or logs would probably come to resemble termites in appearance. However what really separates termites from roaches is the development of a soldier caste. This is a fundamental development which would require much more than merely modifying or losing existing structures or appearances. A soldier caste probably evolved before a worker caste because Mastotermitidae and Kalotermitidae have no worker caste and soldiers only arose once in termites [Rosin, 1994][Thorne 1997]. A soldier caste could only be acquired in a social insect. A soldier caste was with out a doubt extremely valuable for survival of a slow growing insect with nymph mouth parts almost useless for defense. Cryptocercus takes 6 or 7 years to mature. This is more than six times as long as many other insects. This speed of other insects is probably because other insects are usually privileged to eat more nutritious food containing less available calories per protein. I suspect that the wood roach spread around the world when sea levels dropped toward the close of the Permian [Algeo & Seslavinsky, 1995] and reached the Southern Hemisphere near its close. This delay is plausible if the preponderance of their species did not fly, as Cryptocercus does not fly. If Brachiopod distribution is any indication, the latitudes were similar to what they are today [Stehli, 1970]. It is therefore conceivable that they spread across the Bering Sea land bridge. The Canadian arctic was warm early in the Permian (Beauchamp). If it was warm because of a Pacific Ocean current, then the crossing would possibly have to delay until later in the Permian because that implies no land bridge. If that same current still existed when a bridge became established, the southern edge of a Bering Sea bridge would presumably have been warm. It is likely that they crossed this bridge or its water gaps eventually since it is unlikely that they could have spread through Antarctica even though underground and saprophytic insects should be able to tolerate lower winter temperatures than others. The Indian Ocean was very cold in early Permian and judging by glaciers on its northern perimeter as far north as India may even have been filled solid and piled high with ice at that time [Hambrey and Harland]. If the ice was piled as high as a mountain range on its northern perimeter as it approached the moisture of the Tethys Sea, it could have been self perpetuating as the moist northern air rose up on a mountain of ice and dropped huge deposits of snow. It would be unlikely to be destroyed by warm Pacific Ocean currents because there was probably largely land between Australia and Antarctica and between South America and Antarctica. Indeed, there is evidence that this land bridge was largely intact up until mid Eocene [Scher and Martin]. Once the ice reached southern Africa no warm currents could reach the Indian Ocean from the Atlantic either. The aridity of South Africa [Smith] may have been from winds from the southeast drifting down off those glaciers and turning to the west from Coriolis forces. Currently geologists explain this with drifting continents, but shallow earthquakes on ridge – ridge transform faults distant from ridges, mid ocean plateaus, and insufficient trenches to remove the ocean floor make this seem implausible to me. In any case there are early Permian glacial deposits associated with marine deposits around the whole periphery of the Indian Ocean [Hambrey & Harland] and ice moved from west to east, not south to north, in Tasmania [Darlington p182]. An ice filled Indian ocean could explain why the other oceans were so much saltier during the Permian [Knauth]. However the warming at the Permian’s close made almost any kind of migration conceivably possible then. I also suspect that a soldier caste appeared in late Permian and is responsible for the coal hiatus or gap which commenced then and lasted for ten million years. It has been suggested that the soldier caste appeared early in the evolution of termites (Noirot and Pasteels, 1987). Since all primitive termites have flying reproductives, it is obvious that at least some of these ancient prototermites had flying reproductives also and it is possible that none of the wood roaches did. This would help explain why the coal hiatus appeared simultaneously all over the world at the Permian -Triassic boundary [Retallack, 1996, p196]. They may have been able to cross short water gaps for modern termites can cross short water gaps and the possibility that some were more enduring fliers then can not be ruled out. Termites’ mating flights today can reach several thousand meters in the absence of a wind, although usually shorter. The warming at the Permian’s close would have expedited such a migration, as will be discussed . PROTOTERMITES Ants did not appear until the Jurassic, probably descended from a parasitoid Ichneumon Scleroderma based on female polymorphism and similar family instincts combined with the complete lack of family instincts in wasps, as well as similar egg laying habits to ants [Malyshev, 1966, p198-228]. Unlike wasps there are no solitary ants [Bourke & Franks, 1995, p72]. So if roaches evolved a soldier caste at the start of the Triassic, below ground species must have been extraordinarily successful then with only solitary spiders, mantids, centipedes, and dragonflies to contend with. It is very likely that if we had been present in the Triassic we would have thought at first glance that some of them were indeed termites even though they probably retained the roach design of their wings, as does the Mastotermitidae termite today and Mastotermitidae also has similar gizzard, genitalia, and eggs in an ootheca packet [Gillott 1995 p170]. Living underground or inside a log involves pressure to form a thin skin which fossilizes poorly. So they would probably be poorly represented on the fossil record. If only their wings were preserved we would probably have called them roaches. I suspect that they spread through the soil and mulch as much as possible by colony fission as wood roaches do today and, if so, this would have considerably decreased further their fossilization. If winged forms were as successful after mating as I suspect, fossilization of wings would decrease, paradoxically, even further, since the very successful Amitermes meridionalis termite in Australia have very few winged adults or soldiers [Hill, p336] which is probably because of their success in saturating their niche. Eventually some or all of the wood roaches lost their wings since existing species have none [Spirivas 1996]. This, if it obtained, would have decreased fossilization of wood roaches further, since most insect fossils are wings. When a soldier caste actually did appear in a winged prototype we would have had to call them termites (Isoptera) although we might have been reluctant to do so if we lived then. It is highly probable that termites gained their most potent instinct attributes during the Cretaceous. Fossils [Labandeira, 1993] and present day distribution support the last statement. They probably evolve so slowly [Wood & Sands, 1978, P248] that some fundamental social attributes must extend back into the Jurassic or further, at least primitive traits. Hasiotis, et al, have found burrows 0.15 to 0.5 cm in diameter and nests, which they interpret as termite nests up to one meter in diameter in late Triassic North America [Hasiotis, Peterson] [Hasiotis, Brown,Abston, Fig. 251-265], so the beginning of the Triassic is plausible for a termite soldier caste. Termites are extremely varied. Some eat wood. Others eat grass, cambium of trees, or animal dung. A very large number of species eat soil organic matter. The design of their digestive systems vary so drastically and fundamentally [Bignell (has diagrams)] that they must have been evolving for a long time before the Cretaceous by which time they had obviously become well diversified. The duration of the Jurassic would be by no means too long. Whether something resembling a soldier class appeared as far back as the early Triassic can not be determined from present fossils. Gay and Calaby believe that Stolotermes and Porotermes, primitive genera of the Hodotermitidae family, entered Australia through Antarctica in the Triassic [Gay & Calaby (1970), p395]. This is plausible because by the early Triassic the Indian Ocean had become considerably warmer as did the rest of the world. It is conceivable that the design of wood roach mouth parts changed sufficiently then that older nymphs could use them to some extent for defense even though they became less useful for eating hard materials, for defense can be very important to an insect trapped in the close confines of a log or soil cavity. If so, it would have made acquiring a soldier caste much easier. Perhaps when they are analyzed genetically their history will become clearer. The above two genera and the large primitive Zootermopsis and Mastotermes, which retain eyes, would be good genera to start with. There has been such a genetic analysis of the Cryptocercus wood roach and it has been found to be related to Blattidae roaches, which are a sister group to Polyphagidae roaches [Kambhampati 1996]. Removal of litter by ancient insects is quite plausible, for termites are extremely efficient at removing litter at present. Dung takes 25-30 years to be incorporated into desert soil in the absence of termites, while with termites it disappears after the next rain [Whitford, 1986; p107]. Even large resistant items such as large logs have a fairly short life in tropical rain forests while logs in the north where freezing temperatures drastically inhibits the activities of termites, logs lay on the forest floor for many years. I suspect that it was these ancient roaches or more likely prototermites that brought the Carboniferous and Permian coal deposits to an end and produced the Triassic coal hiatus. Termites have then or since developed the ability to oxidize lignin [LaFage & Nutting]. The reduction of litter may have caused the extremes of moisture in the Permian and Triassic red beds because not only does litter and mulch considerably affect keeping soil moist and at an even temperature, but the litter’s own extra moisture stores can cause a considerably enhanced transfer of moisture inland. The Triassic red beds spanned many climates [Retallack, 1996; 201] and started in late Pennsylvanian in North America [Veevers p192]. BOLIDE IMPACT At the close of the Permian at least three extremely drastic extinction events took place on land and at sea. [Erwin, 1994] [Wignall & Hallam, 1993]. They were so sudden and so widespread and diversity of plants and animals was so much reduced on land and especially in the ocean, that they must have been caused by meteorites or comets containing very little iridium [Kajiwara et al., 1994, p375, 377] which overturned an anoxic (lacking oxygen) ocean [Knoll, et al, 1960]. There would have been better than an 80% chance of hitting the ocean. There was a brief erosion which may have been from a tsunami [McLaren & Goodfellow, 1990; p139]. It is not likely that such erosion could have been from terrestrial causes because the tsunami that devastated Indonesia recently was probably as big as they get from earthquakes and it had very little affect on erosion. Such a huge tsunami would have brought carbon dioxide, methane, and poisonous hydrogen sulfide rich water to the surface at tens of thousands of miles of coastline when the wave broke. It would have spread the water over millions of square kilometers of land where the coast was flat. The explosion from a very large bolide (object from space) could have created a tsunami initially kilometers high or more. Such a tsunami would almost certainly be overturned in the immediate vicinity of the impact as well. The resulting tsunami could conceivably have been 50 to 100 meters high in the open ocean [Toon, et al, 1997, p51]. It would have reached tens of thousands of kilometers of coast line. In addition there may have been auxiliary small tsunamis from earthquakes and ejected material [Toon, et al, 1997, p52]. To gain some perspective of possible effects, consider that the tsunami which devastated Hawaii was 20 centimeters high in the open ocean [Toon, et al, p53]. It is thought that a tsunami 10 meters high can flood 20 kilometers inland against a flat plain [Toon, et al, 1997, p53]. There may have been as many as 5 or more surges in carbon dioxide across the years [Holser, 1987, p161] [Kajiwara, et al, 1994, p324]. If so, the worst and middle splashdown which ended the Permian must have taken place in the Atlantic Ocean because marine Permian organisms lasted into the Triassic in eastern China [Wignall & Hallam, 1993]. It is also thought that the Siberian flood basalts were triggered by a very large bolide [Alt, et al]. That flood basalts obliterated large bolide craters is supported by the fact that there are no craters larger than 100 km [Stothers & Rampino p14] TREES Immediately above the boundary the glossopteris flora was suddenly [Hosher p173-174] largely displaced by an Australia wide coniferous flora containing few species and containing a lycopod herbaceous understory. Conifers became common in Eurasia also. Each of these groups of conifers arose from endemic species because conifers are very poor at crossing ocean barriers and they remained separated for hundreds of millions of years, largely to the present. Podocarpis was south and Pines, Junipers, and Sequoias were north, for instance. The dividing line ran through the Amazon Valley, across the Sahara, and north of Arabia, India, Thailand, and Australia [Florin, 1963][Melville, 1966].It has been suggested that there was a climate barrier for the conifers [Darlington, 1965, p168], although water barriers are more plausible to me. COAL HIATUS If so, something which can cross at least short water barriers must have been involved in the coal hiatus. Climate could have been an important auxiliary factor, however. There was a spike of fern and lycopod spores immediately after the close [Retallack, 1995]. In addition there was also a spike of fungal spores immediately after the Permian-Triassic boundary [Eshet & Rampino, 1995 p969] This spike may have lasted 50,000 years in Italy and 200,000 years in China. If so, something besides an instant catastrophe must have been involved in the coal hiatus because funguses would surely have removed all dead vegetation in less than a few years in most tropical places. Besides, the fungal cells rose gradually and declined similarly. There was also much woody debris. Each phenomenon would hint at widespread vegetative death. If the wood roaches and/or prototermites were responsible for a considerable part of this plant death in the years after an impact, it is obvious that they were not nearly as efficient at removing the remaining dead material before the funguses got to it at first as the termites probably were at the Cretaceous extinction and certainly are today. For one thing, they may have been largely confined to removing wood, mulch, and possibly roots because everything else was too poisonous or too out in the open where almost any predator, even dragonflies, could be effective. They, or something, must have become very effective by early Triassic because coal disappeared worldwide. Retallack, et al believe that extinction of peat plants caused it. This does not seem possible because coal formed extensively under rain forests with root traces under the coal. Whatever caused it must have operated in North America 25 million years sooner [Retallack 1996, p196]. Insects which attack the trunk are good candidates for lowering productivity because this is the single most damaging part of the plant to destroy. Such insects would have a considerable indirect effect on the speed of litter removal also, because removal of shade would heat the soil up greatly. The carbon dioxide in the atmosphere which had been rising erratically during the last of the Permian rose to a peak. This widespread plant death , fungal decay, and perhaps wood roach and/or prototermite digestion may have been a measurable part of the cause of that carbon dioxide rise, for there can be considerable carbon contained in the litter and vegetative cover if the thickness of those ancient coal deposits is an indication. During the succeeding Triassic coal hiatus the soil of south Australia was extremely low in organic matter, had no litter at all, and, while stump and root impressions were evident, there were no stumps or roots [Retallack 1997 p193,194] which looks as if they were removed by termites or roaches. Even so it is doubtful if reduction of detritus could have been a major part of the rise in carbon dioxide. A considerable part of it was oxidation of those Pennsylvanian coal deposits which were eroded and oxidized off as the top layers of the Appalachian and Ural mountains rose up. There may have been a fair amount of carbon dioxide released from settling of calcium carbonate as shells [Ridgwell] before the extensive limestone and dolomite under those mountains became exposed and initially even after exposure, because calcium existed in the ocean associated with two bicarbonate ions, while only one carbonate ion precipitated. The reason why initial exposure may not have raised carbon dioxide much from erosion of limestone was because the calcium was probably largely associated with organic acids while in the soil and rivers and preempted carbon dioxide when it reached the ocean. For possible contributions by prototermites to the end Permian extinctions and discussion of the primary source of atmospheric carbon dioxide see this site. REFERENCES for this article are at the end. Continue to Permian marine phosphorus as caused by amphibians, especially dragonflies or to Cretaceous marine phosphorus as caused by sheet erosion from runway building termites, or to the effect of runway builders and incompetent ants on the phosphorus of Cretaceous soils and vertebrate bones and teeth especially dinosaurs. Cretaceous and Eocene marine phosphates are explained as arising from sheet erosion of termite runways at the page about termites affect on soil.. For more details of the termite effect in different areas see the termites’ affect on soil around the Paleocene. For a hypothesis which explains loss of silica from tropical soils by the alkaline gut of termites see Did the alkaline gut of termites cause laterization of soils? For links to information about the Permian age see this site. For those interested in dragonflies try IORI For those interested in modern termites try this extensive worldwide discussion For an electronic journal on paleontology see Palaeontologia Electronica at Paleonet and See this site about insects For a geological time scale. For an unrelated health article which proposes arthritis as a chronic potassium deficiency access this URL. or for an article which proposes copper to prevent hemorrhoids, slipped discs, emphysema, anemia, and maybe gray hair access this URL For an article which describes how to cure a tooth abscess with raw cashew nuts, see this URL, and for some observations on diabetes see this URL. For a hypothesis about human female evolution see this URL. There is a free browser called Firefox, which is said to be less susceptible to viruses or crashes, has many interesting features, imports information from Iexplore while leaving Iexplore intact. You can also install their emailer. A feature that lists all the URLs on a viewed site can be useful when working on your own site. . If you have Iexplore, there is a tool bar by Google that enables you to search the internet from the page viewed, mark desired words, search the site, give page rank, etc. There is a free program available which tells on your site what web site accessed your site, which search engine, statistics about which country, statistics of search engine access, keywords used and their frequency. It can be very useful. REFERENCES DID the WOOD ROACH CAUSE the PERMIAN ARIDITY, RED BEDS, and CONIFER RISE? by Charles Weber Cellulose digestion by wood roaches may have removed enough mulch (detritus) to have caused hiatus of coal, aridity, and some of the temperature rise, as well as increasing conifers in late Permian. The largest part of the temperature rise may have been from overturn of an anoxic ocean by a huge comet. ABSTRACT It is suggested that the symbiosis of cellulose digesting microbes with the cockroach, probably in the Permian, caused fundamental ecological changes which lowered soil organic matter, created aridity, helped increase atmospheric carbon dioxide, helped eliminate glaciers, and favored conifers with their inert interior and wood poisons. In the form of prototermites with a soldier caste, it is suggested that they spread the conifers in early Triassic, caused the early Triassic coal hiatus, and possibly contributed to extinctions at the close of the Permian when dropping sea levels permitted them to spread around the world, the last possibly from the indirect effects of a comet impact coupled to filling of below sea level depressions. INTRODUCTION Living things in the present day display enormous diversity. Many strategies have evolved, especially on land. A large number of plant and animal poisons have appeared. There are several dozen fundamentally different reproductive strategies. Animal and plant sizes are spread over ratios which are billions to one. Numerous ingenious feeding and poison delivery systems have evolved. It is difficult for us living with these current events, which prevent any animal or plant from acquiring an overwhelming advantage, to conceive of a simpler world in which even small changes could have dramatic widespread effects on the ecology and environment. The Permian was a time when many of the basic attributes that we see today first evolved. This article will attempt to explore the effects, which a symbiosis of cellulose digesting microbes with an ancient roach had on the world, probably starting in the Permian. However this, of course, was not a small change. It was as if the vast stores of cellulose in the world had suddenly turned to sugar. There is also a difficulty to perceive that rates of evolution must proceed at drastically different rates. A simple change such as change in size or loss of an existing organ should be able to occur with crisp speed, as we have seen with domesticated organisms. On the other hand, complicated neural patterns such as nest building and intricate organs such as termite poison squirting apparatus must surely require long periods of time. Progenitors of traits like these must surely go back a considerable span from when they first appear on the fossil record, especially when associated with a long lived or sparsely populated organism or when a sudden appearance of diverse forms imply an undiscovered source. DISCUSSION Soil Organic Matter Sometime in the vicinity of the Cambrian period multicelled plants evolved which could synthesize cellulose and live on dry land [Axelrod, 1969]. This, unlike animals, is believed to have happened only once [Kenrik and Crane 1997]. The advantage cellulose gave them was tremendous. Cellulose is a long chain carbohydrate polymer derived from sugar. Not only are there very few organisms which can break the cellulose linkages, but even those which can, do so slowly, because enormously large molecules can form. Its tensile strength is very great, and therefore large stemmed plants were made possible for competition for light. Hydrogen bonding of the polymer chains allowed for considerable shock stress before rupture which prevented brittle fracture in high wind or animal blows. Also important was its lack of palatability and indigestibility to the primitive worms, millipedes, snails and other animals which came out on land then or soon after. As a result, descendants of these plants spread across the land in the form of forests of ferns and other plants by the Devonian. These forests resulted in thin coal seams, which became thicker as the carboniferous went on. One reason why thick coal deposits were able to form was that those early plants made extensive use of lignin. They had bark to wood ratios of 8 to 1, and even as high as 20 to 1. This compares to modern values less than 1 to 4. This bark, which must have been used as support as well as protection, probably had 38% to 58% lignin [Robinson p608]. Lignin is insoluble, too large to pass through cell walls, too heterogeneous for specific enzymes, and toxic, so that few organisms other than Basidiomycetes funguses can degrade it. It can not be oxidized in less than 5% oxygen atmosphere. It can linger in soil for thousands of years and inhibits decay of other substances [Robinson p608]. Probably the reason for its high percentages is protection from insect herbivory in a world containing very effective herbivores, but nothing remotely as effective as modern insectivores and probably much fewer poisons than currently. Roaches It was not until the Carboniferous that large numbers of insects appeared on the fossil record. It is thought that they may have evolved on some as yet unknown island from worm like ancestors similar to the caterpillar like Onychophora, and then became inoculated fully developed into the known continents. Primitive silver fish, collembola, and dragonflies became numerous. The Insect orders became the most important of the herbivorous orders. By the Pennsylvanian, by far the most successful were ancestors of the cockroach. Six fast legs, two well developed folding wings, fairly good eyes, long, well developed antennae (olfactory), an omnivorous digestive system, a receptacle for storing sperm, a chitin skeleton that could support, protect, as well as form a gizzard, and efficient mouth parts gave it formidable advantages over other herbivorous animals. Present day roaches can eat bark, leaves, pith of living cycads, paper, wool, sugar, cheese bread, oil, lemon, flesh, fish, leather, dead roaches [Miall], and earth [author’s observation]. About 90% of insects were roaches [Zimmerman,]. The Pennsylvanian is sometimes known as the age of roaches. Especially significant was their ability to lay their eggs on dry land. The excretion of nitrogen in the form of insoluble uric acid is said to be an important factor in their successful invasion of dry land. [Prosser et al, 1950]. Spiders, centipedes, scorpions, and amphibious vertebrates could take a toll on the ground and ancestors of the dragonfly could catch them in the air, but these predators lacked the efficiency of our best modern predators. Catching them, equipped as they were with efficient sensory and locomotive apparatus, may have been something other than easy. Even where the amphibians and dragonflies were numerous, roaches were probably an effective group, for they grew to great size. Their attack on plants must have been severe, and they also must have had an affect on disease transmission. They were the most important part of the fauna until well into the Triassic [Anderson, et al, 1996]. The fast turnover of plant life helped build up the soil organic content. The large roaches probably could not venture out onto twigs, so they probably caused even more leaf fall than what they managed to eat. Bite marks on leaves are rare, less than 4% [Chaloner]. I suspect that their discards and excreta were a considerable part of the thick layers of litter which later turned into coal. Insects were probably the dominant herbivores then [Shear]. Spore ferns, horse tail rushes, and lycopods or club mosses, were the plants present [Gastaldo, with colored graphs]. The Wood Roach Within the moist upper Pennsylvanian or Permian soil there dwelt a ciliated protozoa capable of digesting particles of cellulose and leaves which descended from above in a never ending rain of insect droppings, etc. and converting them into energy. This microorganism lived under anaerobic conditions since its descendants in wood roaches are anaerobic. There are no such organisms known to be living in the soil or swamps today, but they must have existed at one time. Eventually a roach or roaches evolved, which, instead of digesting that protozoa, formed a symbiosis with it. This meant that now for the first time, a higher animal could make use of the vast stores of cellulose which littered the earth and perhaps even much of that incorporated in the plants, especially the trunks of trees. During the Permian plants started to dominate which made use of dead material high in cellulose in their interiors, such as conifers. According to Kirby the use of cellulose by insects took place in the Permian or Triassic [Steinhaus, 1947; p531]. Fossil wings have been discovered in the Permian of Kansas which have a close resemblance to wings of Mastotermes, which is the most primitive living termite and which is thought to be the descendant of Cryptocercus genus, the wood roach. This fossil is called Pycnoblattina. It folded its wings in a convex pattern between segments 1a and 2a. Mastotermes is the only living insect that does the same [Tilyard RJ 1937]. This is strong circumstantial evidence that the wood roach did evolve in the Permian. If the wood roach is the ancestor of Mastotermes, analysis of its mitochondrial ribosomal DNA for RNA genes [Kambhampati 1995], indicate that a large number of descendants are missing from the fossil record. I suspect that it was the primary change which brought, by the end of the Permian, a close to the carboniferous coal deposits, except in Australia [Tilyard, 1917] at least. Cellulose digestion is inefficient and very rare in insects [Martin], and is probably a recent development in the few other species that have it. Not until the third molt does the nymph complete its symbiosis, possibly because of high pH in the gut [Nalepa, 1990]. As a result, wood roaches have a strong imperative to be social in order to transmit the microbes. This symbiosis probably predated sociality because parental care is rare in Blabeoidea to which family the wood roach is said to belong [Grandicolas 1996, p523]. However, Kambhampati places it neither there nor in Polyphaginae subfamily, but more closely related to Blattidae, so he assigns it to its own family, Cryptocecidae. All this last on the basis of mitochondrial DNA testing [Kambhampati 1996]. The Permian was a transition period in the earth’s history. If the wood roach evolved in this period, it did so in a harsh environment. The Pennsylvanian may have been much different in some areas than the damp coal forests would indicate, but the Permian was definitely characterized by widespread aridity and climatic extremes. Indeed, the effects which wood roaches had on soil organic matter may have caused a considerable part of the climatic extremes. Mulch and organic matter permit considerable infiltration of water into soils by virtue of decreased runoff and increased porosity and also are capable of considerable water storage themselves. As a result moisture can be transferred far inland by air moistened by those stores. In addition, the oxidation of these vast stores of carbon must have caused an increase of the greenhouse effect. This could have caused a small part of the increase of carbon dioxide believed to have occurred in the Permian [Mora et al, 1996] [Berner & Canfield, 1991]. It could not have caused a major rise because the oceans have a tremendous capacity to absorb carbon dioxide. It was probably a triggering affect. The ocean contains fifteen times as much carbon as all terrestrial biotic content and sixty tines the atmosphere. [Walker and Drever 1988, p63][Gregor, et al]. This may be the reason why the oxygen started to drop rapidly at mid Permian while the carbon dioxide only started to rise rapidly starting about two thirds through the Permian [Huey and Ward 2005]. I suspect the bulk of the rise was from oxidation of coal exposed by the rise of the Appalachian and Ural Mountains coupled with a lessened withdrawal by marine shellfish (because of phosphorus surfeit to be discussed in a later article). Initially dissolution of the vast deposits of limestone and dolomite may also have contributed, although eventually such dissolution would actually subtract carbon dioxide from the atmosphere because of making the ocean more alkaline, although half the carbon would be released again when shellfish skeletons settled out. The net affect would have increased temperatures especially in high latitudes [Creber & Chaloner, 1985; p47] and therefore evaporation. While increased atmospheric carbon dioxide would increase temperature, in early Permian, the first major rise followed a temperature rise. This would seem to indicate that a rise in temperature permitted cellulose digesting insects to move toward the poles, and thus increase release of carbon dioxide. When there was a drastic decline in carbon dioxide about 5 million years later, the temperature started its main decline about 2 or 3 million years later, and it did not decline to its value it had at an equivalent carbon dioxide value [Montanez]. So evidently, if insects were a large part of this, something besides temperature caused the roach decline. Subsequent changes in carbon dioxide showed no close parallel to temperature either. The detritus removal also would have increased the areas of deserts. The affect was probably accentuated by a positive feed back implied in the release by warming of the huge stores of methane hydrate [Kvenvolden, 1988] in ocean sediments. In any case the southern glaciers around the Indian ocean subsided during the Permian and after they disappeared, glaciers did not reappear extensively for more than another 200 million years. It is difficult to speculate on the organic content of ancient soils. There is always the chance that carbonaceous material is added to or subtracted from the soil after burial, especially subtracted. Color is a poor indication even in modern soils [Vageler, 1947; p7]. However, coal and black soil shales had virtually disappeared from North America by the last of the Permian, and red shales became common.Red shales may have been caused by high alkalinity in the gut of humus eating roaches. Red shales appeared early in the Permian in South Africa and in late Pennsylvanian in North America and in the mid Permian in Europe and Argentina (Veevers p192). They formed below 40 degrees latitude and were associated with evaporates [Frakes p113], so they must have been in what we now call tropical savanna regions. If the red beds were caused by roaches they were not necessarily cellulose digesting species. Toward the end of the Permian coal began to disappear from the tropics and became increasingly located at higher latitudes, unlike the Carboniferous [Erwin, 1993, p165]. This would be understandable if tropical wood roaches were moving toward the poles in a world which was warming up and they were already eating mulch (detritus) and possibly more importantly, reducing productivity by attacking trees at there most vulnerable place, the trunk interiors. It is probable that some of those roaches, which were making use of mulch directly, we would have been tempted to designate termites or prototermites. This is because burrowing into mulch, soil, or logs imposes environments that require thin skin for respiration in a high carbon dioxide atmosphere, and favors loss of pigments and eyes. Also modern wood roaches are devoid of wings [Srinivas et al., 1996] and the most numerous species of humus eaters may have been so devoid then. Since they probably rarely or never flew or even emerged from their tunnels they would not have been likely to leave many fossils. However, their prototypes probably did leave fossils. Tilyard believes that Pycnoblattina genus of the Pyknoblattinae subfamily fossils from lower Permian Kansas are very similar to Mastotermes and are either an ancestor or sister group, as already mentioned. He bases this observation on the fact that the wing hinge of the rear wing is in the same location as Mastotermes and is found on no other modern insect (Tilyard 1937, p171 & 266). Most of the fossils are forewings. This may be because of the nature of Arachnid predation [[Duncan et al 2003]. There are no soft body parts known yet, but the pronotum head covering is similar in both genera also. There are a few fossil hard head parts which also bear some resemblance to Mastotermes.(Tilyard, p274), and other aspects of wing venation have many points of similarity. Termites may have evolved from one of the forms similar to wood roaches roaches and acquired their symbiosis from wood roaches. Gene sequences for 18s mitochondrial cytochrome oxidase subunit II and endogenous endo-beta-1, 4-glucanase indicates termites and wood roaches are in the same clade [Lo]. So it is fitting that we describe one of the two known survivors as reported by Cleveland [Cleveland et al., 1934]. The name of this roach is Cryptocercus punctulatus. It manages to exist in a narrow belt in the temperate regions where the winters are not too severe. It has no wings, is about 2.5 centimeters long, and manages to subsist in small colonies inside rotten logs. It still retains most of the roach features, but it bears some resemblance to termites. Its nymphs are not pigmented. The mouth parts are very similar to worker termites. Strangely enough it has a peculiar jerky motion at certain times, which some termites use. Its courtship is similar to termites and it mates before, during, and after it lays eggs [Nalepa, 1988]. Most fundamental of all is the close similarity of the digestive system to that of termites, including a symbiosis with cellulose digesting protozoa housed in the hind gut which are lost after each molt. It has a primitive social structure, required for transmittal of its protozoa after a molt. All these facts constitute circumstantial evidence that this insect is closely related to the ancestor of the termites. However it does not leave any additional clues as to the importance of its progenitors in ancient ages. For this, a look at its protozoan population is instructive. Its hind intestine contains nine genera of Hypermastigina class, one of which is known from termites, and three genera from the more primitive Polymastigina, two of which are known in termites. A single species of termites is not found to have a random protozoa population in nature and does not vary [Steinhaus, 1947; p531]. If ancient roaches interchanged protozoa with equal difficulty, it implies evolution of a numerous population for a considerable time until displaced by termites. There has been an interchange affected in the laboratory, though. Nevertheless, at first glance it would seem that this roach might represent the survivor of a once much more numerous family of insects which remained so for a long time. The wood roach has a more complicated digestive system than termites, which would seem to be further indication of this possibility. Of course termites could have evolved from non symbiotic sister group of wood roaches long after the wood roaches we know, by transfer of the protozoa, and this could have diversified rapidly long after wood roaches had first appeared. Nalepa and Thorne disagree as to the likelyhood of the transfer of symbionts between termites and roaches in the past [Thorne][Nalepa, 1991]. However in the course of several hundred million years transfer without a doubt occurred times without number without necessarily taking, so not only is either hypothesis possible but both may be involved on several occasions. The difficulty in this aspect of evolution is not with termite habits or protozoa evolution per se but more likely the nature of the molecules termites must be synthesizing in order to control the protozoa and prevent disease and “weeds”. I doubt if we have enough information to resolve the matter at present. The likelihood that termites themselves are derived from a single ancestral group is especially possible if you define a termite as a roach with a soldier caste. However most digestive features probably existed before the coal hiatus. The Australian wood eating cockroach secretes an enzyme which digests cellulose and is almost devoid of protozoa [Scrivener, et al., 1989]. This must surely be a late development after termite progenitors developed a soldier caste because a symbiosis would not have been necessary if this trait had developed early on. It is conceivable that some of the termites developed from a cousin of this roach and then subsequently some of them lost the enzyme. However it is very unlikely because the most primitive termites lack this enzyme and the soldier caste only evolved once [Rosin, 1994]. Termites which have a cellulose digesting enzyme, such as reticulitermes, produces only small amounts of glucose at the salivary gland [Watanabe & Noda]. Coptotermes and Nasutitermes secrete cellulase only from the salivary gland [Hogan]. Even if such an enzyme existed then in that form (as opposed to being reevolved later), it would not likely have been important or interfered with protozoan evolution. TERMITES Any social roach which bored into the soil or logs would probably come to resemble termites in appearance. However what really separates termites from roaches is the development of a soldier caste. This is a fundamental development which would require much more than merely modifying or losing existing structures or appearances. A soldier caste probably evolved before a worker caste because Mastotermitidae and Kalotermitidae have no worker caste and soldiers only arose once in termites [Rosin, 1994][Thorne 1997]. A soldier caste could only be acquired in a social insect. A soldier caste was with out a doubt extremely valuable for survival of a slow growing insect with nymph mouth parts almost useless for defense. Cryptocercus takes 6 or 7 years to mature. This is more than six times as long as many other insects. This speed of other insects is probably because other insects are usually privileged to eat more nutritious food containing less available calories per protein. I suspect that the wood roach spread around the world when sea levels dropped toward the close of the Permian [Algeo & Seslavinsky, 1995] and reached the Southern Hemisphere near its close. This delay is plausible if the preponderance of their species did not fly, as Cryptocercus does not fly. If Brachiopod distribution is any indication, the latitudes were similar to what they are today [Stehli, 1970]. It is therefore conceivable that they spread across the Bering Sea land bridge. The Canadian arctic was warm early in the Permian (Beauchamp). If it was warm because of a Pacific Ocean current, then the crossing would possibly have to delay until later in the Permian because that implies no land bridge. If that same current still existed when a bridge became established, the southern edge of a Bering Sea bridge would presumably have been warm. It is likely that they crossed this bridge or its water gaps eventually since it is unlikely that they could have spread through Antarcti

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