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)


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,
This project contains
  • 90 Media
  • 1 Taxon
  • 2 Specimens
Total size of project's media files: 358.45M

Download Project SDD File
Currently Viewing:
MorphoBank Project 2503

    Authors' Institutions

    • Museum für Naturkunde - Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Berlin

    • Humboldt-Universitaet zu Berlin (Humboldt University Berlin)

    • Universite de Montpellier

    • Universidade Nova de Lisboa

    • Universidade de Lisboa

    • Southern Methodist University

    • European Synchrotron Radiation Facility


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

    Project has no matrices defined.

    Project views

    type number of views Individual items viewed (where applicable)
    Total project views17759
    Project overview1456
    Media views13446Media search (1172 views); M426121 (130 views); M426076 (163 views); M426077 (150 views); M426052 (166 views); M426049 (149 views); M426084 (138 views); M426129 (146 views); M426117 (134 views); M426107 (137 views); M426109 (118 views); M426057 (147 views); M426058 (114 views); M426124 (148 views); M426110 (143 views); M426086 (128 views); M426123 (126 views); M426134 (126 views); M426053 (154 views); M426104 (134 views); M426093 (113 views); M426108 (120 views); M426044 (134 views); M426141 (124 views); M426138 (121 views); M426098 (131 views); M426130 (127 views); M426125 (134 views); M426136 (126 views); M426082 (140 views); M426041 (121 views); M426097 (116 views); M426115 (130 views); M426133 (122 views); M426054 (153 views); M426113 (144 views); M426112 (131 views); M426072 (155 views); M426092 (125 views); M426103 (126 views); M426039 (168 views); M435889 (129 views); M426033 (157 views); M426042 (158 views); M426046 (140 views); M426047 (143 views); M426048 (134 views); M426051 (140 views); M426055 (171 views); M426056 (179 views); M426060 (160 views); M426061 (166 views); M426062 (153 views); M426063 (135 views); M426064 (153 views); M426065 (139 views); M426067 (136 views); M426068 (134 views); M426069 (123 views); M426070 (135 views); M426071 (132 views); M426073 (137 views); M426074 (148 views); M426080 (131 views); M426081 (145 views); M426083 (119 views); M426085 (131 views); M426087 (142 views); M426088 (121 views); M426089 (116 views); M426091 (129 views); M426094 (123 views); M426095 (126 views); M426100 (167 views); M426101 (119 views); M426102 (128 views); M426105 (137 views); M426106 (121 views); M426111 (148 views); M426114 (118 views); M426116 (124 views); M426119 (145 views); M426122 (125 views); M426126 (132 views); M426127 (143 views); M426131 (124 views); M426132 (123 views); M426135 (171 views); M426137 (127 views); M426139 (112 views); M426140 (113 views);
    Taxon list771
    Views for media list976
    Specimen list779
    Documents list1

    Project downloads

    type number of downloads Individual items downloaded (where applicable)
    Total downloads from project105
    Media downloads2M426077 (2 downloads);
    Project downloads103