Skip to main content
×
Home
    • Aa
    • Aa

Patterns in the evolution of nares size and secondary palate length in anomodont therapsids (Synapsida): implications for hypoxia as a cause of end-Permian tetrapod extinctions

  • Kenneth D. Angielczyk (a1) and Melony L. Walsh (a2)
Abstract

Seemingly consistent proportional differences in several palatal structures have been noted between Permian and Triassic anomodont therapsids for nearly a century. These patterns have been cited as evidence in support of a decline in atmospheric oxygen concentrations that may have contributed to end-Permian terrestrial extinctions. However, it is not known whether the observed differences are significant, or whether they stem from continued directional selection. If they are not significant, or if their timing does not match that proposed for the oxygen decline, support for the hypoxia-based extinction scenario would be weakened. We tested whether the internal nares and bony secondary palate, two palatal features proposed to be related to respiratory efficiency, are significantly larger in Triassic anomodonts, and whether the variation can be attributed to a long-term tendency for increase. Results based on raw data indicate that Triassic anomodonts have significantly larger secondary palates than Permian anomodonts. They also have significantly larger internal nares, but only when primitive, morphologically-divergent specimens are not considered. Although nares and palate size are correlated with stratigraphic occurrence, available data reject the hypothesis that the observed differences were the result of a long-term trend. Most of these findings are consistent with the predictions of the hypoxia scenario. However, removing the effects of body size and phylogeny causes some of the differences to break down, indicating that if selection for increased respiratory efficiency affected these characters, it was most likely not the only factor to do so. Therefore, the characters provide only weak evidence in support of the hypoxia scenario, and we recommend against their use for this purpose. Our results emphasize the need for caution when invoking presumed differences between Permian and Triassic vertebrates as support for hypoxia, or other extinction scenarios, without a rigorous study of the character(s) in question.

Copyright
References
Hide All
K. D. Angielczyk 2002. Redescription, phylogenetic position, and stratigraphic significance of the dicynodont genus Odontocyclops (Synapsida; Therapsida). Journal of Paleontology, 76:10471059.

K. D. Angielczyk 2004. Phylogenetic evidence for and implications of a dual origin of propaliny in anomodont therapsids (Synapsida). Paleobiology, 30:268296.

K. D. Angielczyk 2007. New specimens of the Tanzanian dicynodont “Cryptocynodon” parringtoni Von Huene, 1942 (Therapsida, Anomodontia), with an expanded analysis of Permian dicynodont phylogeny. Journal of Vertebrate Paleontology, 27:116131.

K. D. Angielczyk and A. A. Kurkin 2003. Phylogenetic analysis of Russian Permian dicynodonts (Therapsida: Anomodontia): Implications for Permian biostratigraphy and Pangaean biogeography. Zoological Journal of the Linnean Society, 139:157212.

C. M. Beall 2006. Andean, Tibetan, and Ethiopian patterns of adaptation to high-altitude hypoxia. Integrative and Comparative Biology, 46:1824.

C. M. Beall , M. J. Decker , G. M. Brittenham , I. Kushner , A. Gebremedhin , and K. P. Strohl 2002. An Ethiopian pattern of human adaptation to high-altitude hypoxia. Proceedings of the National Academy of Sciences, 99:1721517218.

C. M. Beall , K. P. Strohl , J. Blangero , S. Williams-Blangero , L. A. Almasy , M. J. Decker , C. M. Worthman , M. C. Goldstein , E. Vargas , M. Villena , R. Soria , A. M. Alarcon , and C. Gonzales 1997. Ventilation and hypoxic ventilatory response of Tibetan and Aymara high altitude natives. American Journal of Physical Anthropology, 104:427447.

R. A. Berner 1987. Models for carbon and sulfur cycles and atmospheric oxygen: Application to Paleozoic geologic history. American Journal of Science, 287:177196.

R. A. Berner 1989. Drying, O2 and extinction. Nature, 340:603604.

R. A. Berner 1999. Atmospheric oxygen over Phanerozoic time. Proceedings of the National Academy of Science, 96:1095510957.

R. A. Berner 2001. Modeling atmospheric O2 over Phanerozoic time. Geochimica et Cosmochimica Acta, 65:685694.

R. A. Berner 2005. The carbon and sulfur cycles and atmospheric oxygen from middle Permian to middle Triassic. Geochimica et Cosmochimica Acta, 69:3211–17.

R. A. Berner and D. Canfield 1989. A new model for atmospheric oxygen over Phanerozoic time. American Journal of Science, 289:333361.

R. A. Berner , D. J. Beerling , R. Dudley , J. M. Robinson , and R. A. Wildman 2003. Phanerozoic atmospheric oxygen. Annual Reviews of Earth and Planetary Science, 31:105134.

J. Botha and K. D. Angielczyk 2007. An integrative approach to distinguishing the Late Permian dicynodont species Oudenodon bainii and Tropidostoma microtrema (Therapsida: Anomodontia). Palaeontology, 50: 11751209.

J. Botha and R. M. H. Smith 2006. Rapid vertebrate recuperation in the Karoo Basin of South Africa following the end-Permian extinction. Journal of African Earth Sciences, 45:502514.

J. Botha and R. M. H. Smith 2007. Lystrosaurus species composition across the Permo-Triassic boundary in the Karoo Basin of South Africa. Lethaia, 40:125137.

C. B. Cox 1965. New Triassic dicynodonts from South America, their origins and relationships. Philosophical Transactions of the Royal Society of London Series B, 248:457516.

C. B. Cox 1998. The jaw function and adaptive radiation of the dicynodont mammal-like reptiles of the Karoo basin of South Africa. Zoological Journal of the Linnean Society, 122:349384.

A. R. I. Cruickshank 1967. A new dicynodont genus from the Manda Formation of Tanzania (Tanganyika). Journal of Zoology, 153:163208.

F. M. Faraci 1991. Adaptations to hypoxia in birds: How to fly high. Annual Review of Physiology, 53:5970.

J. Felsenstein 1985. Phylogenies and the comparative method. American Naturalist, 125:115.

J. Fröbisch 2006. Locomotion in derived dicynodonts (Synapsida, Anomodontia): A functional analysis of the pelvic girdle and hind limb of Tetragonias njalilus. Canadian Journal of Earth Sciences, 43:12971308.

J. Fröbisch 2007. The cranial anatomy of Kombuisia frerensis Hotton (Synapsida, Dicynodontia) and a new phylogeny of anomodont therapsids. Zoological Journal of the Linnean Society, 150:117144.

T. Garland and A. R. Ives 2000. Using the past to predict the present: Confidence intervals for regression equations in phylogenetic comparative methods. American Naturalist, 155:346364.

T. Garland , A. F. Bennett , and E. L. Rezende 2005. Phylogenetic approaches in comparative physiology. Journal of Experimental Biology, 208: 30153035.

D. Germain and M. Laurin 2005. Microanatomy of the radius and lifestyle in amniotes (Vertebrata, Tetrapoda). Zoologica Scripta, 34:335350.

J. L. Gittleman and H.-K. Luh 1992. On comparing comparative methods. Annual Review of Ecology and Systematics, 23:383404.

A. Grafen 1989. The phylogenetic regression. Philosophical Transactions of the Royal Society of London Series B, 326:157199.

J. B. Graham , R. Dudley , N. M. Aguilar , and C. Gans 1995. Implications of the late Paleozoic oxygen pulse for physiology and evolution. Nature, 375:117120.

R. B. Huey and P. D. Ward 2005. Hypoxia, global warming, and terrestrial Late Permian extinctions. Science, 308:398401.

A. C. Lasaga 1989. A new approach to isotopic modeling of the variation of atmospheric oxygen through the Phanerozoic. American Journal of Science, 289:411435.

M. Laurin 2004. The evolution of body size, Cope's Rule and the origin of amniotes. Systematic Biology, 53:594622.

A. M. Lorino , M. P. d'Ortho , E. Dahan , O. Bignani , C. Vastel , and H. Lorino 2001. Combined effects of a nasal dilator and nasal prongs on nasal airflow resistance. Chest, 120:397401.

A. M. Lorino , F. Lofaso , I. Drogou , F. Abi-Nader , E. Dahan , A. Coste , and H. Lorino 1998. Effects of different mechanical treatments on nasal resistance assessed by rhinometry. Chest, 114:166170.

S. G. Lucas 1998. Global Trissic tetrapod biostratigraphy and biochronology. Palaeogeography, Palaeoclimatology, Palaeoecology, 143:347384.

N. MacLeod 2001. The role of phylogeny in quantitative paleobiological data analysis. Paleobiology, 27:226240.

W. P. Maddison 1991. Squared-change parsimony reconstructions of ancestral states for continuous-valued characters on a phylogenetic tree. Systematic Zoology, 40:304314.

M. W. Maisch 2002. A new basal lystrosaurid dicynodont from the Upper Permian of South Africa. Palaeontology, 45:343359.

M. W. Maisch and E. V. I. Gebauer 2005. Reappraisal of Geikia locusticeps (Therapsida: Dicynodontia) from the Upper Permian of Tanzania. Palaeontology, 48:309324.

E. P. Martins and T. F. Hansen 1997. Phylogenies and the comparative method: A general approach to incorporating phylogenetic information into the analysis of interspecific data. American Naturalist, 149:646667.

E. P. Martins , J. A. F. Diniz-Filho , and E. A. Housworth 2002. Adaptive constraints and the phylogenetic comparative method. Evolution, 56:113.

B. K. McNab 1978. The evolution of endothermy in the phylogeny of mammals. American Naturalist, 112:121.

H.-H. Meissner , S. M. Santiago , S. N. Koyal , A. Riemer , M. Sein , M. D. Goldman , and A. J. Williams 1999. Characteristics of nasal airflow and the effect of a nasal dilator in normal human subjects. Respiration Physiology, 115:95101.

D. B. Miles and A. E. Dunham 1993. Historical perspectives in ecology and evolutionary biology: The use of phylogenetic comparative analyses. Annual Review of Ecology and Systematics, 24:587619.

S. P. Modesto , B. Rubidge , and J. Welman 1999. The most basal anomodont therapsid and the primacy of Gondwana in the evolution of the anomodonts. Proceedings of the Royal Society of London Series B, 266: 331337.

S. P. Modesto , B. Rubidge , and J. Welman 2002. A new dicynodont therapsid from the lowermost Beaufort Group, Upper Permian of South Africa. Canadian Journal of Earth Sciences, 39:17551765.

S. P. Modesto , B. Rubdige , I. Visser , and J. Welman 2003. A new basal dicynodont from the Upper Permian of South Africa. Palaeontology, 46: 211223.

H. Palomino , W. H. Mueller , and W. J. Schull 1979. Altitude, heredity, and body proportions in northern Chile. American Journal of Physical Anthropology, 50:3950.

S. Ray 2005. Lystrosaurus (Therapsida, Dicynodontia) from India: Taxonomy, relative growth, and cranial dimorphism. Journal of Systematic Palaeontology, 3:203221.

S. Ray 2006. Functional and evolutionary aspects of the postcranial anatomy of dicynodonts (Synapsida, Therapsida). Palaeontology, 49:12631286.

S. Ray and A. Chinsamy 2003. Functional aspects of the postcranial anatomy of the Permian dicynodont Diictodon and their ecological implications. Palaeontology, 46:151183.

S. Ray , A. Chinsamy , and S. Bandyopadhyay 2005. Lystrosaurus murrayi (Therapsida, Dicynodontia): Bone histology, growth, and lifestyle adaptations. Palaeontology, 48:11691185.

G. J. Retallack 2004. Vertebrate extinction across Permian-Triassic boundary in Karoo Basin, South Africa: Reply. Geological Society of America Bulletin, 116:12951296.

G. J. Retallack , C. A. Metzger , T. Greaver , A. H. Jahren , R. M. H. Smith , and N. D. Sheldon 2006. Middle-Late Permian mass extinction on land. Geological Society of America Bulletin, 118:13981411.

G. J. Retallack , R. M. H. Smith , and P. D. Ward 2003. Vertebrate extinction across Permian-Triassic boundary in Karoo Basin, South Africa. Geological Society of America Bulletin, 115:11331152.

F. J. Rohlf 2001. Comparative methods for the analysis of continuous variables: Geometric interpretations. Evolution, 55:21432160.

B. S. Rubidge 2005. Re-uniting lost continents—fossil reptiles from the ancient Karoo and their wanderlust. South African Journal of Geology, 108: 135172.

N. Rybczynski 2000. Cranial anatomy and phylogenetic position of Suminia getmanovi, a basal anomodont (Amniota: Therapsida) from the Late Permian of Eastern Europe. Zoological Journal of the Linnean Society, 130:329373.

G. Savourney , J.-C. Launay , Y. Besnard , A. Guinet , and S. Travers 2003. Normo- and hypobaric hypoxia: Are there any physiological differences? European Journal of Applied Physiology, 89:122126.

C. A. Sidor 2003a. Evolutionary trends and the origin of the mammalian lower jaw. Paleobiology, 29:605640.

C. A. Sidor 2003b. The naris and palate of Lycaenodon longiceps (Therapsida: Biarmosuchia), with comments on their early evolution in the Therapsida. Journal of Paleontology, 77:977984.

R. Smith and J. Botha 2005. The recovery of terrestrial vertebrate diversity in the South African Karoo Basin after the end-Permian extinction. Comptes Rendus Palevol, 4:623636.

H.-D. Sues and R. R. Reisz 1998. Origins and early evolution of herbivory in tetrapods. Trends in Ecology and Evolution, 13:141145.

M. V. Surkov and M. J. Benton 2004. The basicranium of dicynodonts (Synapsida) and its use in phylogenetic analysis. Palaeontology, 47:619638.

M. V. Surkov , N. N. Kalandadze , and M. J. Benton 2005. Lystrosaurus georgi, a dicynodont from the Lower Triassic of Russia. Journal of Vertebrate Paleontology, 25:402413.

M. J. Toerien 1955. Convergent trends in Anomodontia. Evolution, 9:152156.

T. Thulborn and S. Turner 2003. The last dicynodont: An Australian Cretaceous relict. Proceedings of the Royal Society of London Series B, 270:985993.

P. D. Ward , J. Botha , R. Buick , M. O. De Kock , D. H. Erwin , G. Garrison , J. Kirschvink , and R. Smith 2005. Abrupt and gradual extinction among Late Permian land vertebrates in the Karoo Basin, South Africa. Science, 307:709714.

Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

Journal of Paleontology
  • ISSN: 0022-3360
  • EISSN: 1937-2337
  • URL: /core/journals/journal-of-paleontology
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
×

Metrics

Abstract views

Total abstract views: 83 *
Loading metrics...

* Views captured on Cambridge Core between September 2016 - 17th October 2017. This data will be updated every 24 hours.