Permian Life: Before the Dinosaurs

Biotic Responses to the Permo-Triassic Mass Extinction

About thirty million years before the dinosaurs and their relatives (“archosaurs”) took center stage as Earth’s major charismatic megafauna, the Permian period ended with a lasting global biodiversity crisis that disrupted links in animal communities both on land and in the seas. This event, sometimes called the “Mother of Mass Extinctions” is known to paleontologists as the Permo-Triassic mass extinction (or sometimes End-Permian mass extinction) (ca. 252 million years ago). Although its cause remains elusive, this major period of ecological turnover shared many characteristics with the K-Pg extinction that would kill-off the non-avian dinosaurs nearly two hundred million years later, but with a much higher death toll wiping-out some 90% of animal species. It is estimated that animal communities did not return to their former ecological diversity until some five-to-eight million years later, during the Middle Triassic period.

Locations of important Permian and Triassic vertebrate-bearing localities in southern Gondwana (Karoo Basin, South Africa; Zambia; Malawi; Tanzania; central-Transantarctic Mountains)

Locations of important Permian and Triassic vertebrate-bearing localities in southern Gondwana (Karoo Basin, South Africa; Zambia; Malawi; Tanzania; central-Transantarctic Mountains). [from Sidor & al. (2013) Proceedings of the National Academy of Science: fig. 1]

New research on this extinction seeks to record ecological diversity and richness across the Permo-Triassic transition in order to better understand whether the catastrophic nature of mass extinctions permits normal ecological patterns as seen during background intervals (i.e., constructive selectivity) and how these extinctions reset the rules for biotic recoveries. Our contribution to this research demonstrates that (1) smaller body sizes generally conferred greater probability of lineage survival and (2) post-extinction taxa living in the immediate aftermath of the extinction were generally short-lived with a relatively short period of subadult growth. Collaborative research on other Gonwanan faunas is also showing that post-extinction communities became increasingly provincialized by the Middle Triassic, with the waning of synapsid-dominated faunas and the emergence of diverse archosaur-rich communities across Gondwana (and perhaps across the Pangean supercontinent more generally).

Selected Publications:

Codron, J., J. Botha-Brink, D. Codron, A. K. Huttenlocker, and K. D. Angielczyk. 2016 (for 2017). Predator-prey interactions among Permo-Triassic terrestrial vertebrates as a deterministic factor influencing faunal collapse and turnover. For Journal of Evolutionary Biology 30. doi:10.1111/jeb.12983

Botha-Brink, J., D. Codron, A. K. Huttenlocker, K. D. Angielczyk, and M. Ruta. 2016. Breeding young as a survival strategy during Earth’s greatest mass extinction. Scientific Reports 6:srep24053. doi:10.1038/srep24053

Sidor, C. A., R. M. H. Smith, A. K. Huttenlocker, and B. R. Peecook. 2014. New Middle Triassic tetrapods from the upper Fremouw Formation of Antarctica and their depositional setting. Journal of Vertebrate Paleontology 34:793–801. doi:10.1080/02724634.2014.837472

Huttenlocker, A. K. 2014. Body size reductions in nonmammalian eutheriodont therapsids (Synapsida) during the end-Permian mass extinction. PLOS ONE 9:e87553. doi: 10.1371/journal.pone.0087553

Botha-Brink, J., A. K. Huttenlocker, & S. P. Modesto. 2014. Vertebrate Paleontology of Nooitgedacht 68: A Lystrosaurus maccaigi-rich Permo-Triassic Boundary locality in South Africa. In Early Evolutionary History of the Synapsida– Eds., C. Kammerer, K. Angielczyk, and J. Frobisch. Springer.

Sidor, C., D. Vilhena, K. Angielczyk, A. Huttenlocker, S. Nesbitt, B. Peecook, S. Steyer, R. Smith, & L. Tsuji. 2013. Provincialization of terrestrial faunas following the end-Permian mass extinction. Proceedings of the National Academy of Sciences of the United States of America 110:8129–8133. doi:10.1073/pnas.1302323110

Huttenlocker, A. K., and J. Botha-Brink. 2013. Body size and growth patterns in the therocephalian Moschorhinus (Therapsida) before and after the end-Permian extinction in South Africa. Paleobiology 39:253–277. doi:10.1666/12020

Huttenlocker, A. K., & C. A. Sidor. 2012. Taxonomic revision of therocephalians (Therapsida) from Antarctica. American Museum Novitates 3738:1–19.

Huttenlocker, A. K., C. A. Sidor, & R. M. H. Smith. 2011. A new specimen of Promoschorhynchus (Therapsida: Therocephalia: Akidnognathidae) from the lowermost Triassic of South Africa and its implications for theriodont survivorship across the Permo-Triassic boundary. Journal of Vertebrate Paleontology 31:405–421.


Paleoecology of Land-based Communities During the Carboniferous-Permian Transition: The Earth’s Last Icehouse-Hothouse Transition

The Carboniferous-Permian (C-P) transition (ca. 300 million years ago) is our best deep-time analog of present day climate warming. At its onset, the southern hemisphere was largely glaciated and cool-temperate forests were apparently wide spread, even at near equatorial latitudes. Subsequently, however, the transition into the Permian brought a shift from global icehouse to hothouse conditions, including increased seasonal aridity in paleoequatorial regions, and an associated, geographically diachronous replacement of wet ‘Carboniferous-type’ floras by conifers and more xeric or dry-adapted floras.


Using paleohistology as a tool for reconstructing the biology of Permian tetrapods and their environmental interactions. A-C, Histologic cross-section of Dimetrodon neural spine records growth, remodeling, and attachment sites for muscles (l.p.b., lamellar primary bone; S.f., Sharpey’s fibers); D, former UW undergrad Jeff Benca samples organic shales near the Carboniferous-Permian boundary for pollen and spores; E, nearly complete skeleton of a burrowing lysorophian from the Eskridge Formation, Nebraska (inset: histologic thin-section of lungfish rib from same assemblage showing lines of arrested growth [arrows] indicating multi-seasonal residence in ephemeral pools prior to death and burial.)

This research explores spatial variation in responses of terrestrial vertebrates to climate change, including regional provincialism and shifts in vertebrate distributions during the C-P transition. Observations by our team indicate that in western and central Pangea dry-adapted faunas began to proliferate relatively early during this transition, predominantly along a northwest-southeast gradient toward the margins of the Tethys seaway, and were associated with significant regional homogenization and seasonally adaptive behaviors, such as estivation and burrowing behavior. We want to characterize the dynamics of these spatial and temporal shifts because it will allow us to better understand (1) how accurately regional problems can be applied to global-scale questions (e.g., extra-basinal correlations and biostratigraphy, global biodiversity, etc.), (2) how changing climates have influenced the evolution of terrestrial plant and animal communities, their abilities to disperse, and the adaptive value of novel life history and behavioral strategies in new environments; and (3) the long term influences of future climate change on present-day communities. Our current work focuses on comparisons between terrestrial vertebrate assemblages of the northern US midcontinent (Nebraska, Kansas) and four corners (Utah, Colorado, New Mexico) to those of the better known “red beds” of Texas and Oklahoma.

Selected Publications & Abstracts:

Pardo, J. D., A. K. Huttenlocker, and B. J. Small. 2014. An exceptionally preserved transitional lungfish from the Lower Permian of Nebraska, USA, and the origin of modern lungfishes. PLOS ONE 9:e108542. doi:10.1371/journal.pone.0108542

Huttenlocker, A. K., J. D. Pardo, B. J. Small, and J. S. Anderson. 2013. Cranial morphology of recumbirostrans from the Permian of Kansas and Nebraska, and early morphological evolution inferred by micro-computed tomography. Journal of Vertebrate Paleontology 33:540–552. doi:10.1080/02724634.2013.728998

Benca, J., C. Strömberg, & A. Huttenlocker. 2013. Do leaf margin-climatic proxies exist for the Paleozoic? New Mexico Museum of Natural History and Science Carboniferous-Permian Transition Symposium, Albuquerque.

May, W., A. K. Huttenlocker, J. D. Pardo, J. Benca, & B. J. Small. 2011. New Upper Pennsylvanian armored dissorophid records (Temnospondyli: Dissorophoidea) from the US midcontinent and the stratigraphic distributions of dissorophids. Journal of Vertebrate Paleontology 31:907-912.

Huttenlocker, A. K., J. D. Pardo, B. J. Small, & A. Milner.  2008. Biotic responses to climate change in the Permo-Carboniferous transition, Part 2: Beta diversity, regional responses, and Vaughn’s faunal cline.  Society of Vertebrate Paleontology 68th Annual Meeting, Cleveland.

Pardo, J. D., A. K. Huttenlocker, B. J. Small, & A. Milner.  2008. Biotic responses to climate change in the Permo-Carboniferous transition, Part 1: Vertebrate faunal distributions and regional provincialism.  Society of Vertebrate Paleontology 68th Annual Meeting, Cleveland.

Englehorn, J., B. J. Small, & A. Huttenlocker. 2008. Anatomy and relationships of Acroplous vorax (Amphibia: Dvinosauroidea): new specimens from the Lower Permian of Nebraska and Kansas. Journal of Vertebrate Paleontology 28:291-305.

Huttenlocker, A. K., B. J. Small, & J. Pardo. 2007. Plemmyradytes shintoni gen. et sp. nov., an Early Permian amphibamid (Temnospondyli: Dissorophoidea) from the Eskridge Formation, Nebraska. Journal of Vertebrate Paleontology 27:316-328

Small, B. J., J. D. Pardo, & A. K. Huttenlocker. 2006. Taxonomic diversity of estivating species in the lowest Permian of North America: onset of seasonality and comments on physiological plasticity. Society of Vertebrate Paleontology 66th Annual Meeting, Ottawa.

Huttenlocker, A. K., J. D. Pardo, & B. J. Small. 2005. An earliest Permian nonmarine vertebrate assemblage from the Eskridge Formation, Nebraska. Pp. 133-143 in S. G. Lucas and K. E. Ziegler (eds.) The Nonmarine Permian: Bulletin of the New Mexico Museum of Natural History and Science 30.

Huttenlocker, A. K., J. Pardo, & B. J. Small.  2005.  An earliest Permian nonmarine vertebrate assemblage from the Eskridge Formation (Council Grove Group), Nebraska.  New Mexico Museum of Natural History and Science Nonmarine Permian Symposium, Albuquerque.