Project 2503: R. Araújo, V. Fernandez, M. J. Polcyn, J. Fröbisch, R. M. Martins. 2017. Aspects of gorgonopsian paleobiology and evolution: insights from the basicranium, occiput, osseous labyrinth, vasculature, and neuroanatomy. PeerJ. 5:e3119.
Specimen: † Aloposaurus gracilis (:GPIT/RE/7124)

Abstract

Synapsida, the clade including therapsids and thus also mammals, is one of the two major branches of amniotes. Organismal design, with modularity as a concept, offers insights into the evolution of therapsids, a group that experienced profound anatomical transformations throughout the past 270Ma, eventually leading to the evolution of the mammalian bauplan. However, the anatomy of some therapsid groups remains obscure. Gorgonopsian braincase anatomy is poorly known and many anatomical aspects of the brain, cranial nerves, vasculature, and osseous labyrinth, remain unclear. We analyzed two gorgonopsian specimens, GPIT/RE/7124 and GPIT/RE/7119, using propagation phase contrast synchrotron micro-computed tomography. The lack of fusion between many basicranial and occipital bones in GPIT/RE/7124, which is an immature specimen, allowed us to reconstruct its anatomy and ontogenetic sequence, in comparison with the mature GPIT/RE/7119, in great detail. We explored the braincase and rendered various skull cavities. Notably, we found that there is a separate ossification between what was previously referred to as the “parasphenoid” and the basioccipital. We reinterpreted this element as a posterior ossification of the basisphenoid: the basipostsphenoid. Moreover, we show that the previously called “parasphenoid” is in fact the co-ossification of the dermal parasphenoid and the endochondral basipresphenoid. In line with previous descriptions, the anatomy of the osseous labyrinth is rendered in detail, revealing a unique discoid morphology of the horizontal semicircular canal, rather than toroidal, probably due to architectural constraints of the ossification of the opisthotic and supraoccipital. In addition, the orientation of the horizontal semicircular canal suggests that gorgonopsians had an anteriorly tilted alert head posture. The morphology of the brain endocast is in accordance with the more reptilian endocast shape of other non-mammaliaform neotherapsids.


Read the article »

Article DOI: 10.7717/peerj.3119

Project DOI: 10.7934/P2503, http://dx.doi.org/10.7934/P2503
This project contains
  • 90 Media
  • 1 Taxon
  • 2 Specimens
Total size of project's media files: 364 MB

Download Project SDD File
Currently Viewing:
MorphoBank Project 2503

    Authors' Institutions

    • Humboldt-Universitaet zu Berlin

    • Universite de Montpellier

    • Universidade Nova de Lisboa

    • Universidade de Lisboa

    • Southern Methodist University

    • European Synchrotron Radiation Facility

    • Leibniz-Institut für Evolutions- und Biodiversitätsforschung



    Members

    member name taxa specimens media
    Ricardo Araújo
    Project Administrator
    Last logged in 03/31/17
    1290


    Project has no matrices defined.



    Project views

    type number of views Individual items viewed (where applicable)
    Total project views16591
    Project overview1380
    Media views12551Media search (1092 views); M426121 (121 views); M426076 (151 views); M426077 (142 views); M426052 (158 views); M426049 (141 views); M426084 (130 views); M426129 (136 views); M426117 (125 views); M426107 (128 views); M426109 (109 views); M426057 (136 views); M426058 (106 views); M426124 (139 views); M426110 (136 views); M426086 (120 views); M426123 (116 views); M426134 (119 views); M426053 (146 views); M426104 (122 views); M426093 (105 views); M426108 (110 views); M426044 (126 views); M426141 (115 views); M426138 (112 views); M426098 (124 views); M426130 (117 views); M426125 (127 views); M426136 (117 views); M426082 (132 views); M426041 (113 views); M426097 (104 views); M426115 (121 views); M426133 (113 views); M426054 (144 views); M426113 (136 views); M426112 (123 views); M426072 (147 views); M426092 (117 views); M426103 (113 views); M426039 (156 views); M435889 (119 views); M426033 (150 views); M426042 (149 views); M426046 (131 views); M426047 (134 views); M426048 (127 views); M426051 (129 views); M426055 (162 views); M426056 (171 views); M426060 (150 views); M426061 (157 views); M426062 (145 views); M426063 (127 views); M426064 (142 views); M426065 (131 views); M426067 (125 views); M426068 (125 views); M426069 (113 views); M426070 (125 views); M426071 (123 views); M426073 (129 views); M426074 (137 views); M426080 (120 views); M426081 (134 views); M426083 (110 views); M426085 (121 views); M426087 (131 views); M426088 (112 views); M426089 (106 views); M426091 (120 views); M426094 (115 views); M426095 (117 views); M426100 (157 views); M426101 (112 views); M426102 (119 views); M426105 (128 views); M426106 (114 views); M426111 (138 views); M426114 (108 views); M426116 (116 views); M426119 (135 views); M426122 (118 views); M426126 (124 views); M426127 (135 views); M426131 (115 views); M426132 (113 views); M426135 (161 views); M426137 (118 views); M426139 (103 views); M426140 (105 views);
    Taxon list722
    Views for media list902
    Specimen list735
    Bibliography300
    Documents list1




    Project downloads

    type number of downloads Individual items downloaded (where applicable)
    Total downloads from project97
    Media downloads2M426077 (2 downloads);
    Project downloads95