Humeral morphology of the early Eocene mekosuchine crocodylian Kambara from the Tingamarra Local Fauna southeastern Queensland, Australia

Stein, Michael, Salisbury, Steven W., Hand, Suzanne J., Archer, Michael and Godthelp, Henk (2012) Humeral morphology of the early Eocene mekosuchine crocodylian Kambara from the Tingamarra Local Fauna southeastern Queensland, Australia. Alcheringa, 36 4: 473-486. doi:10.1080/03115518.2012.671697


Author Stein, Michael
Salisbury, Steven W.
Hand, Suzanne J.
Archer, Michael
Godthelp, Henk
Title Humeral morphology of the early Eocene mekosuchine crocodylian Kambara from the Tingamarra Local Fauna southeastern Queensland, Australia
Journal name Alcheringa   Check publisher's open access policy
ISSN 0311-5518
1752-0754
Publication date 2012-01
Sub-type Article (original research)
DOI 10.1080/03115518.2012.671697
Volume 36
Issue 4
Start page 473
End page 486
Total pages 14
Place of publication Colchester, Essex, United Kingdom
Publisher Taylor & Francis
Collection year 2013
Language eng
Abstract Mekosuchines (Crocodylia; Crocodyloidea) were a clade of crocodylians endemic to Australia and the South Pacific that underwent radiation during the Cenozoic. Numerous questions about mekosuchine palaeoecology remain unanswered. Tantalizing among these is the possibility that some mekosuchines were primarily terrestrial. To date, studies of mekosuchines have focused mainly on the cranium. However, the morphological signal for terrestriality is more likely to be found in the postcranial skeleton. Here, we present a comparative morphological study of fossil humeri referable to Kambara from the early Eocene Tingamara Local Fauna, Murgon, southeastern Queensland. The humeri of Kambara do not show the torsion between the proximal and distal extremity seen in extant crocodylians, illustrated here with Crocodylus porosus and Crocodylus johnstoni. They also differ in the structure of the medial and lateral condyles of the distal extremity. When the effects of these features on musculature and articulation are considered, it appears that the forelimb of Kambara could have facilitated a greater force at the glenohumeral joint and possibly swung the lower forelimb faster with a greater arc of motion than Australia's extant crocodylians. This is conducive to an improved capacity for both terrestrial locomotion and paraxial swimming. Although the former case suggests that Kambara may not have been as closely tied to water as extant crocodylians, it is unusual given the typically broad rostra of the cranium. Among crocodylians this is a common characteristic of semi-aquatic ambush predators. This study shows the utility of the postcranial skeleton in interpreting crocodylian palaeoecology.
Keyword Mekosuchinae
Kambara
Morphology
Postcranium
Humeral torsion
Palaeoecology
Terrestriality
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2013 Collection
School of Biological Sciences Publications
 
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