Project 2781: M. R. Stocker, C. A. Brochu, E. C. Kirk. 2021. A new caimanine alligatorid from the Middle Eocene of Southwest Texas and implications for spatial and temporal shifts in Paleogene crocodyliform diversity. PeerJ. 9:e10665.
Abstract
Dramatic early Cenozoic climatic shifts resulted in faunal reorganization on a global scale. Among vertebrates, multiple groups of mammals (e.g. adapiform and omomyiform primates, mesonychids, taeniodonts, dichobunid artiodactyls) are well known from the Western Interior of North America in the warm, greenhouse conditions of the early Eocene, but a dramatic drop in the diversity of these groups, along with the introduction of more dry-tolerant taxa, occurred near the Eocene–Oligocene boundary. Crocodyliforms underwent a striking loss of diversity at this time as well. Pre-Uintan crocodyliform assemblages in the central Western Interior are characterized by multiple taxa, whereas Chadronian assemblages are depauperate with only Alligator prenasalis previously known. Crocodyliform diversity through the intervening Uintan and Duchesnean is not well understood. The middle Eocene Devil’s Graveyard Formation (DGF) of southwest Texas provides new data from southern latitudes during that crucial period. A new specimen from the middle member of the DGF (late Uintan–Duchesnean) is the most complete cranial material of an alligatorid known from Paleogene deposits outside the Western Interior. We identify this specimen as a caimanine based on notched descending laminae of the pterygoids posterior to the choanae and long descending processes of the exoccipitals that are in contact with the basioccipital tubera. Unlike Eocaiman cavernensis, the anterior palatine process is rounded rather than quadrangular. The relationships and age of this new taxon support the hypothesis that the modern distribution of caimanines represents a contraction of a more expansive early Cenozoic distribution. We hypothesize that the range of caimanines tracked shifting warm, humid climatic conditions that contracted latitudinally toward the hothouse-icehouse transition later in the Eocene.Read the article »
Article DOI: 10.7717/peerj.10665
Project DOI: 10.7934/P2781, http://dx.doi.org/10.7934/P2781
This project contains | Matrices |
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Download Project SDD File | Total scored cells: 6950 Total media associated with cells: 0 Total labels associated with cell media: 0 |
Characters | |
Total characters: 202 Total characters with associated media: 0 Total characters with media with labels: 0 Total character states: 473 Total character states with associated media: 0 Total character states with media with labels:0 Total unordered/ordered characters:202/0 |
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MorphoBank Project 2781
MorphoBank Project 2781
- Creation Date:
06 November 2017 - Publication Date:
06 January 2021 - Project views: 11444
- Matrix downloads: 26
Authors' Institutions
- University of Iowa
- University of Texas at Austin
- Virginia Tech (Virginia Polytechnic Institute and State University)
Members
member name | taxa | specimens | media | chars | character
| cell scorings (scored, NPA, "-") | cell
| rules | ||||||
Michelle Stocker Project Administrator | 58 | 1 | 1 | 197 | 0 | 0 | 0 (0, 0, 0) | 0 | 0 | 0 | ||||
Christopher Brochu Full membership | 1 | 0 | 0 | 5 | 0 | 0 | 6950 (6950, 0, 0) | 0 | 0 | 0 | ||||
Christopher Kirk Full membership | 0 | 0 | 0 | 0 | 0 | 0 | 0 (0, 0, 0) | 0 | 0 | 0 |
Taxonomic Overview for Matrix 'M26813' (58 Taxa)
taxon | unscored cells |
scored cells |
no cell support |
NPA cells |
"-" cells | cell images | labels on cell images |
member access |
[1] † Borealosuchus sternbergii Last Modified in 01/06/21 | 20 | 182 | 182 | 0 | 0 | 0 | 0 | 3 |
[2] † Boverisuchus vorax Last Modified in 01/06/21 | 53 | 149 | 149 | 0 | 0 | 0 | 0 | 3 |
[3] † Leidyosuchus canadensis Last Modified in 01/06/21 | 38 | 164 | 164 | 0 | 0 | 0 | 0 | 3 |
[4] † Diplocynodon ratelii Last Modified in 01/06/21 | 41 | 161 | 161 | 0 | 0 | 0 | 0 | 3 |
[5] † Diplocynodon hantoniensis Last Modified in 01/06/21 | 39 | 163 | 163 | 0 | 0 | 0 | 0 | 3 |
[6] † Diplocynodon darwini Last Modified in 01/06/21 | 40 | 162 | 162 | 0 | 0 | 0 | 0 | 3 |
[7] † Diplocynodon deponiae Last Modified in 01/06/21 | 105 | 97 | 97 | 0 | 0 | 0 | 0 | 3 |
[8] † Diplocynodon remensis Last Modified in 01/06/21 | 53 | 150 | 149 | 0 | 0 | 0 | 0 | 3 |
[9] † Stangerochampsa mccabei Last Modified in 01/06/21 | 40 | 162 | 162 | 0 | 0 | 0 | 0 | 3 |
[10] † Albertochampsa langstoni Last Modified in 01/06/21 | 130 | 72 | 72 | 0 | 0 | 0 | 0 | 3 |
[11] † Brachychampsa montana Last Modified in 01/06/21 | 26 | 176 | 176 | 0 | 0 | 0 | 0 | 3 |
[12] † Brachychampsa sealeyi Last Modified in 01/06/21 | 139 | 63 | 63 | 0 | 0 | 0 | 0 | 3 |
[13] Alligator sinensis Last Modified in 07/03/20 | 5 | 197 | 197 | 0 | 0 | 0 | 0 | 3 |
[14] Alligator mississippiensis Last Modified in 07/03/20 | 1 | 201 | 201 | 0 | 0 | 0 | 0 | 3 |
[15] † Alligator mefferdi Last Modified in 01/06/21 | 59 | 143 | 143 | 0 | 0 | 0 | 0 | 3 |
[16] † Alligator thompsoni Last Modified in 01/06/21 | 82 | 120 | 120 | 0 | 0 | 0 | 0 | 3 |
[17] † Alligator olseni Last Modified in 01/06/21 | 58 | 144 | 144 | 0 | 0 | 0 | 0 | 3 |
[18] † Alligator mcgrewi Last Modified in 01/06/21 | 28 | 174 | 174 | 0 | 0 | 0 | 0 | 3 |
[19] † Alligator prenasalis Last Modified in 01/06/21 | 30 | 172 | 172 | 0 | 0 | 0 | 0 | 3 |
[20] † Ceratosuchus burdoshi Last Modified in 01/06/21 | 121 | 81 | 81 | 0 | 0 | 0 | 0 | 3 |
[21] † Allognathosuchus polyodon Last Modified in 01/06/21 | 125 | 77 | 77 | 0 | 0 | 0 | 0 | 3 |
[22] † Allognathosuchus wartheni Last Modified in 01/06/21 | 64 | 138 | 138 | 0 | 0 | 0 | 0 | 3 |
[23] † Navajosuchus mooki Last Modified in 01/06/21 | 73 | 129 | 129 | 0 | 0 | 0 | 0 | 3 |
[24] † Wannaganosuchus brachymanus Last Modified in 01/06/21 | 79 | 123 | 123 | 0 | 0 | 0 | 0 | 3 |
[25] † Procaimanoidea kayi Last Modified in 01/06/21 | 71 | 131 | 131 | 0 | 0 | 0 | 0 | 3 |
[26] † Procaimanoidea utahensis Last Modified in 01/06/21 | 83 | 119 | 119 | 0 | 0 | 0 | 0 | 3 |
[27] † Arambourgia gaudryi Last Modified in 01/06/21 | 98 | 104 | 104 | 0 | 0 | 0 | 0 | 3 |
[28] † Necrosuchus ionensis Last Modified in 01/06/21 | 167 | 35 | 35 | 0 | 0 | 0 | 0 | 3 |
[29] † Tsoabichi greenriverensis Last Modified in 01/06/21 | 141 | 61 | 61 | 0 | 0 | 0 | 0 | 3 |
[30] † Purussaurus mirandai Last Modified in 01/06/21 | 82 | 120 | 120 | 0 | 0 | 0 | 0 | 3 |
[31] † Purussaurus brasiliensis Last Modified in 01/06/21 | 107 | 95 | 95 | 0 | 0 | 0 | 0 | 3 |
[32] † Purussaurus neivensis Last Modified in 01/06/21 | 45 | 157 | 157 | 0 | 0 | 0 | 0 | 3 |
[33] † Mourasuchus atopus Last Modified in 01/06/21 | 58 | 144 | 144 | 0 | 0 | 0 | 0 | 3 |
[34] † Mourasuchus amazonensis Last Modified in 01/06/21 | 160 | 42 | 42 | 0 | 0 | 0 | 0 | 3 |
[35] † Mourasuchus arendsi Last Modified in 01/06/21 | 144 | 58 | 58 | 0 | 0 | 0 | 0 | 3 |
[36] † Mourasuchus nativus Last Modified in 01/06/21 | 120 | 82 | 82 | 0 | 0 | 0 | 0 | 3 |
[37] † Eocaiman cavernensis Last Modified in 01/06/21 | 161 | 41 | 41 | 0 | 0 | 0 | 0 | 3 |
[38] Caiman yacare Last Modified in 07/03/20 | 1 | 201 | 201 | 0 | 0 | 0 | 0 | 3 |
[39] Caiman crocodilus Last Modified in 07/03/20 | 1 | 201 | 201 | 0 | 0 | 0 | 0 | 3 |
[40] Caiman latirostris Last Modified in 07/03/20 | 6 | 196 | 196 | 0 | 0 | 0 | 0 | 3 |
[41] † La venta caiman Last Modified in 01/06/21 | 143 | 59 | 59 | 0 | 0 | 0 | 0 | 3 |
[42] † Melanosuchus fisheri Last Modified in 01/06/21 | 127 | 75 | 75 | 0 | 0 | 0 | 0 | 3 |
[43] Melanosuchus niger Last Modified in 07/03/20 | 4 | 198 | 198 | 0 | 0 | 0 | 0 | 3 |
[44] Paleosuchus trigonatus Last Modified in 07/03/20 | 3 | 199 | 199 | 0 | 0 | 0 | 0 | 3 |
[45] Paleosuchus palpebrosus Last Modified in 01/06/21 | 6 | 196 | 196 | 0 | 0 | 0 | 0 | 3 |
[46] † Caiman brevirostris Last Modified in 01/06/21 | 136 | 66 | 66 | 0 | 0 | 0 | 0 | 3 |
[47] † Centenariosuchus gilmorei Last Modified in 01/06/21 | 173 | 29 | 29 | 0 | 0 | 0 | 0 | 3 |
[48] † Globidentosuchus brachyrostris Last Modified in 01/06/21 | 126 | 76 | 76 | 0 | 0 | 0 | 0 | 3 |
[49] Crocodylus affinis Last Modified in 07/03/20 | 29 | 173 | 173 | 0 | 0 | 0 | 0 | 3 |
[50] † Asiatosuchus germanicus Last Modified in 01/06/21 | 61 | 141 | 141 | 0 | 0 | 0 | 0 | 3 |
[51] † Gnatusuchus pebasensis Last Modified in 01/06/21 | 86 | 116 | 116 | 0 | 0 | 0 | 0 | 3 |
[52] † Kuttanacaiman iquitosensis Last Modified in 01/06/21 | 76 | 126 | 126 | 0 | 0 | 0 | 0 | 3 |
[53] † Caiman wannlangstoni Last Modified in 01/06/21 | 100 | 102 | 102 | 0 | 0 | 0 | 0 | 3 |
[54] † Protocaiman peligrensis Last Modified in 01/06/21 | 170 | 32 | 32 | 0 | 0 | 0 | 0 | 3 |
[55] † Eocaiman palaeocenicus Last Modified in 01/06/21 | 189 | 13 | 13 | 0 | 0 | 0 | 0 | 3 |
[56] † Eocaiman itaboraiensis Last Modified in 01/06/21 | 198 | 4 | 4 | 0 | 0 | 0 | 0 | 3 |
[57] † TxVP 45911-1 Last Modified in 01/06/21 | 124 | 78 | 78 | 0 | 0 | 0 | 0 | 3 |
[58] † Bottosaurus harlani Last Modified in 01/06/21 | 122 | 80 | 80 | 0 | 0 | 0 | 0 | 3 |
Project views
type | number of views | Individual items viewed (where applicable) |
Total project views | 11444 | |
Project overview | 1101 | |
Matrix views | 762 | Matrix used in analysis (91 views); Matrix landing page (671 views); |
Documents list | 559 | |
Media views | 2112 | Media search (1789 views); M692323 (323 views); |
Views for media list | 618 | |
Specimen list | 1112 | |
Taxon list | 4721 | |
Bibliography | 459 |
Project downloads
type | number of downloads | Individual items downloaded (where applicable) |
Total downloads from project | 126 | |
Project downloads | 99 | |
Matrix downloads | 26 | Matrix used in analysis (26 downloads); |
Document downloads | 1 | Complete character list in docx format (1 download); |