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Article: Postcranial morphology of the Early Triassic epicynodont Galesaurus planiceps (Owen) from the Karoo Basin, South Africa

Papers in Palaeontology - Volume 5 Issue 1 - Cover
Publication: Palaeontology
Volume: 5
Part: 1
Publication Date: Febuary 2019
Page(s): 1 32
Author(s): Elize Butler, Fernando Abdala, and Jennifer Botha‐Brink
DOI: 10.1002/spp2.1220
Addition Information

How to Cite

BUTLER, E., ABDALA, F., BOTHA‐BRINK, J. 2019. Postcranial morphology of the Early Triassic epicynodont Galesaurus planiceps (Owen) from the Karoo Basin, South Africa . Papers in Palaeontology, 5, 1, 1-32. DOI: /doi/10.1002/spp2.1220

Author Information

  • Elize Butler - Karoo Palaeontology National Museum PO Box 266 Bloemfontein 9300 South Africa
  • Elize Butler - Department of Zoology & Entomology University of the Free State Bloemfontein 9300 South Africa
  • Fernando Abdala - Evolutionary Studies Institute & School of Geosciences University of the Witwatersrand Private Bag 3 WITS 2050 Johannesburg South Africa
  • Fernando Abdala - Unidad Ejecutora Lillo CONICET Miguel Lillo 251 Tucumán Argentina
  • Jennifer Botha‐Brink - Karoo Palaeontology National Museum PO Box 266 Bloemfontein 9300 South Africa
  • Jennifer Botha‐Brink - Department of Zoology & Entomology University of the Free State Bloemfontein 9300 South Africa

Publication History

  • Issue published online: 18 February 2019
  • Manuscript Accepted: 05 April 2018
  • Manuscript Received: 13 October 2017

Funded By

National Research Foundation. Grant Numbers: 95980, 98819
Palaeontological Scientific Trust (PAST) and its Scatterlings of Africa programmes
DST/NRF Centre of Excellence in Palaeosciences
Conicet, Argentina

Online Version Hosted By

Wiley Online Library (Free Access)
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Abstract

The Early Triassic non‐mammaliaform epicynodont Galesaurus planiceps formed an important part of ecosystems following the Permo‐Triassic Mass Extinction, the greatest mass extinction in Phanerozoic history. Here, we re‐examine the postcranial skeleton of Galesaurus and present data which sheds light on the biology, ecology and possible survival strategies of this species. We find evidence for two distinct morphotypes, a gracile and a robust morph, which we interpret as stages in an ontogenetic series. The primary differences between the morphs manifest in the girdles, with further subtle differences in the fore and hind limbs. Our study also reveals postcranial differences between Galesaurus and the contemporaneous taxon Thrinaxodon liorhinus, allowing these taxa to be distinguished in the absence of cranial material. We also report the first evidence of intraspecific variation in the presence and distribution of disc‐like phalanges in a non‐mammaliaform cynodont. An analysis of the osteohistology of Galesaurus reveals rapid growth to skeletal maturity within one year, thereafter transitioning to slow intermittent growth. This growth pattern is similar to that of Thrinaxodon, which also grew rapidly and continuously to skeletal, and possibly reproductive, maturity within its first year of life. Features such as a strong, reinforced pelvis, elongated ilium, thick, robust forelimbs and stout unguals indicate that Galesaurus was capable of actively excavating burrows. The combination of rapid maturation and fossoriality may have aided its survival in the harsh, unpredictable post‐extinction Early Triassic environment.

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