Project 2495: A. Pritchard, A. Turner, R. Irmis, S. Nesbitt, N. Smith. 2016. Extreme Modification of the Tetrapod Forelimb in a Triassic Diapsid Reptile. Current Biology. 26 (20):2779-2786.
Abstract
The tetrapod forelimb is one of the most versatile structures in vertebrate evolution, having been co-opted for an enormous array of functions. However, the structural relationships between the bones of the forelimb have remained largely unchanged throughout the 375 million year history of Tetrapoda, with a radius and ulna made up of elongate, paralleling shafts contacting a series of shorter carpal bones. These features are consistent across nearly all known tetrapods, suggesting that the morphospace encompassed by these taxa is limited by some sort of constraint(s). Here, we report on a series of three-dimensionally preserved fossils of the small-bodied (<1 m) Late Triassic diapsid reptile Drepanosaurus, from the Chinle Formation of New Mexico, USA, which dramatically diverge from this pattern. Along with the crushed type specimen from Italy, these specimens have a flattened, crescent-shaped ulna with a long axis perpendicular to that of the radius and hyperelongate, shaft-like carpal bones contacting the ulna that are proximodistally longer than the radius. The second digit supports a massive, hooked claw. This condition has similarities to living “hook-and-pull” digging mammals and demonstrates that specialized, modern ecological roles had developed during the Triassic Period, over 200 million years ago. The forelimb bones in Drepanosaurus represent previously unknown morphologies for a tetrapod and, thus, a dramatic expansion of known tetrapod forelimb morphospace.Read the article »
Article DOI: 10.1016/j.cub.2016.07.084
Project DOI: 10.7934/P2495, http://dx.doi.org/10.7934/P2495
This project contains | Matrices |
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Download Project SDD File | Total scored cells: 1019 Total media associated with cells: 0 Total labels associated with cell media: 0 |
Characters | |
Total characters: 75 Total characters with associated media: 0 Total characters with media with labels: 0 Total character states: 160 Total character states with associated media: 0 Total character states with media with labels:0 Total unordered/ordered characters:69/6 |
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MorphoBank Project 2495
MorphoBank Project 2495
- Creation Date:
13 July 2016 - Publication Date:
29 September 2016 - Matrix downloads: 17
This research
supported by
Authors' Institutions
- Virginia Tech (Virginia Polytechnic Institute and State University)
- Natural History Museum of Los Angeles County
- Natural History Museum of Utah
- Stony Brook University
Members
member name | taxa | specimens | media | chars | character
| cell scorings (scored, NPA, "-") | cell
| rules | ||||||
Adam Pritchard Project Administrator | 20 | 0 | 1 | 75 | 0 | 0 | 1019 (1001, 0, 18) | 0 | 0 | 0 |
Taxonomic Overview for Matrix 'M24116' (20 Taxa)
taxon | unscored cells |
scored cells |
no cell support |
NPA cells |
"-" cells | cell images | labels on cell images |
member access |
[1] † Petrolacosaurus kansasensis Taxon name last Modified on 10/06/16 | 1 | 73 | 73 | 0 | 1 | 0 | 0 | 1 |
[2] Shinisaurus crocodilurus Taxon name last Modified on 10/06/16 | 2 | 70 | 70 | 0 | 3 | 0 | 0 | 1 |
[3] Uromastyx sp. Taxon name last Modified on 07/13/16 | 3 | 70 | 70 | 0 | 2 | 0 | 0 | 1 |
[5] † Diphydontosaurus avonis Taxon name last Modified on 10/06/16 | 34 | 42 | 41 | 0 | 0 | 0 | 0 | 1 |
[6] Sphenodon punctatum Taxon name last Modified on 10/06/16 | 0 | 73 | 72 | 0 | 3 | 0 | 0 | 1 |
[7] † Saurosternon bainii Taxon name last Modified on 10/06/16 | 46 | 28 | 28 | 0 | 1 | 0 | 0 | 1 |
[8] † Protorosaurus speneri Taxon name last Modified on 10/06/16 | 3 | 71 | 71 | 0 | 1 | 0 | 0 | 1 |
[9] † Azendohsaurus madagaskarensis Taxon name last Modified on 10/06/16 | 2 | 72 | 72 | 0 | 1 | 0 | 0 | 1 |
[11] † Macrocnemus bassanii Taxon name last Modified on 10/06/16 | 23 | 52 | 52 | 0 | 0 | 0 | 0 | 1 |
[12] † Tanystropheus longobardicus Taxon name last Modified on 10/06/16 | 2 | 72 | 72 | 0 | 1 | 0 | 0 | 1 |
[13] † Claudiosaurus germaini Taxon name last Modified on 10/06/16 | 3 | 71 | 71 | 0 | 1 | 0 | 0 | 1 |
[14] † Hovasaurus boulei Taxon name last Modified on 10/06/16 | 13 | 62 | 61 | 0 | 1 | 0 | 0 | 1 |
[15] † Thadeosaurus colcanapi Taxon name last Modified on 10/06/16 | 25 | 49 | 49 | 0 | 1 | 0 | 0 | 1 |
[16] † Dolabrosaurus aquatilis Taxon name last Modified on 10/06/16 | 55 | 20 | 20 | 0 | 0 | 0 | 0 | 1 |
[18] † gr113 Taxon name last Modified on 10/06/16 | 69 | 6 | 6 | 0 | 0 | 0 | 0 | 1 |
[19] † Drepanosaurus unguicaudatus Taxon name last Modified on 10/06/16 | 37 | 38 | 38 | 0 | 0 | 0 | 0 | 1 |
[20] † HaydenDrepanosaur Taxon name last Modified on 10/06/16 | 64 | 11 | 11 | 0 | 0 | 0 | 0 | 1 |
[21] † Hypuronector limnaios Taxon name last Modified on 10/06/16 | 47 | 27 | 27 | 0 | 1 | 0 | 0 | 1 |
[22] † Megalancosaurus preonensis Taxon name last Modified on 10/06/16 | 22 | 53 | 53 | 0 | 0 | 0 | 0 | 1 |
[23] † Vallesaurus cenensis Taxon name last Modified on 10/06/16 | 33 | 41 | 41 | 0 | 1 | 0 | 0 | 1 |
Project downloads
type | number of downloads | Individual items downloaded (where applicable) |
Total downloads from project | 303 | |
Project downloads | 286 | |
Matrix downloads | 17 | Extreme modification of the tetrapod forelimb in a Triassic diapsid reptile (17 downloads); |