Project 4761: J. D. Pardo, M. Szostakiwskyj, P. E. Ahlberg, J. S. Anderson. 2017. Hidden morphological diversity among early tetrapods. Nature. 546 (7660):642-645.
Abstract
Phylogenetic analysis of early tetrapod evolution has resulted in a consensus across diverse data sets in which the tetrapod stem group is a relatively homogenous collection of medium- to large-sized animals showing a progressive loss of 'fish' characters as they become increasingly terrestrial, whereas the crown group demonstrates marked morphological diversity and disparity. The oldest fossil attributed to the tetrapod crown group is the highly specialized aïstopod Lethiscus stocki, which shows a small size, extreme axial elongation, loss of limbs, spool-shaped vertebral centra, and a skull with reduced centres of ossification, in common with an otherwise disparate group of small animals known as lepospondyls. Here we use micro-computed tomography of the only known specimen of Lethiscus to provide new information that strongly challenges this consensus. Digital dissection reveals extremely primitive cranial morphology, including a spiracular notch, a large remnant of the notochord within the braincase, an open ventral cranial fissure, an anteriorly restricted parasphenoid element, and Meckelian ossifications. The braincase is elongate and lies atop a dorsally projecting septum of the parasphenoid bone, similar to stem tetrapods such as embolomeres. This morphology is consistent in a second aïstopod, Coloraderpeton, although the details differ. Phylogenetic analysis, including critical new braincase data, places aïstopods deep on the tetrapod stem, whereas another major lepospondyl lineage is displaced into the amniotes. These results show that stem group tetrapods were much more diverse in their body plans than previously thought. Our study requires a change in commonly used calibration dates for molecular analyses, and emphasizes the importance of character sampling for early tetrapod evolutionary relationships.Read the article »
Article DOI: 10.1038/nature22966
Project DOI: 10.7934/P4761, http://dx.doi.org/10.7934/P4761
This project contains | Matrices |
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Download Project SDD File | Total scored cells: 15199 Total media associated with cells: 0 Total labels associated with cell media: 0 |
Characters | |
Total characters: 370 Total characters with associated media: 0 Total characters with media with labels: 0 Total character states: 867 Total character states with associated media: 0 Total character states with media with labels:0 Total unordered/ordered characters:370/0 |
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MorphoBank Project 4761
MorphoBank Project 4761
- Creation Date:
19 July 2023 - Publication Date:
28 July 2023 - Project views: 4994
Authors' Institutions
- University of Calgary
- Uppsala University
Members
member name | taxa | specimens | media | chars | character
| cell scorings (scored, NPA, "-") | cell
| rules | ||||||
Shreya Jariwala Project Administrator | 58 | 14 | 14 | 370 | 0 | 0 | 15199 (14181, 0, 1018) | 0 | 0 | 0 | ||||
Brooke Long-Fox Full membership | 0 | 0 | 0 | 0 | 0 | 0 | 0 (0, 0, 0) | 0 | 0 | 0 |
Taxonomic Overview for Matrix 'M29370' (58 Taxa)
taxon | unscored cells |
scored cells |
no cell support |
NPA cells |
"-" cells | cell images | labels on cell images |
member access |
[1] † Archeria crassidisca Last Modified in 07/20/23 | 50 | 309 | 308 | 0 | 12 | 0 | 0 | 2 |
[2] † Crassigyrinus scoticus Last Modified in 07/20/23 | 82 | 281 | 281 | 0 | 7 | 0 | 0 | 2 |
[3] † Acanthostega gunnari Last Modified in 07/20/23 | 15 | 350 | 349 | 0 | 6 | 0 | 0 | 2 |
[4] † Eusthenopteron foordi Last Modified in 07/20/23 | 154 | 196 | 196 | 0 | 20 | 0 | 0 | 2 |
[5] † Ichthyostega spp. Last Modified in 07/20/23 | 57 | 307 | 305 | 0 | 8 | 0 | 0 | 2 |
[6] † Panderichthys rhombolepis Last Modified in 07/20/23 | 263 | 107 | 107 | 0 | 0 | 0 | 0 | 2 |
[7] † Pederpes finneyae Last Modified in 07/20/23 | 163 | 203 | 203 | 0 | 4 | 0 | 0 | 2 |
[8] † Tiktaalik rosaea Last Modified in 07/20/23 | 91 | 245 | 244 | 0 | 35 | 0 | 0 | 2 |
[9] † Ventastega curonica Last Modified in 07/20/23 | 125 | 241 | 241 | 0 | 4 | 0 | 0 | 2 |
[10] † Whatcheeria deltae Last Modified in 07/20/23 | 86 | 278 | 277 | 0 | 7 | 0 | 0 | 2 |
[11] † Ymeria denticulata Last Modified in 07/20/23 | 268 | 101 | 100 | 0 | 2 | 0 | 0 | 2 |
[12] † Proterogyrinus scheelei Last Modified in 07/20/23 | 46 | 317 | 313 | 0 | 11 | 0 | 0 | 2 |
[13] † Balanerpeton woodi Last Modified in 07/20/23 | 77 | 286 | 286 | 0 | 7 | 0 | 0 | 2 |
[14] † Dendrerpeton acadianum Last Modified in 07/20/23 | 46 | 318 | 316 | 0 | 8 | 0 | 0 | 2 |
[15] † Pantylus cordatus Last Modified in 07/20/23 | 11 | 340 | 339 | 0 | 20 | 0 | 0 | 2 |
[16] † Cardiocephalus peabodyi Last Modified in 07/20/23 | 206 | 157 | 156 | 0 | 8 | 0 | 0 | 2 |
[17] † Huskerpeton englehorni Last Modified in 07/20/23 | 107 | 243 | 243 | 0 | 20 | 0 | 0 | 2 |
[18] † Pelodosotis elongatum Last Modified in 07/20/23 | 51 | 301 | 300 | 0 | 19 | 0 | 0 | 2 |
[19] † Nannaroter mckinzei Last Modified in 07/20/23 | 165 | 186 | 186 | 0 | 19 | 0 | 0 | 2 |
[20] † Micraroter erythrogeios Last Modified in 07/20/23 | 94 | 258 | 256 | 0 | 20 | 0 | 0 | 2 |
[21] † Eocaecilia micropodia Last Modified in 07/20/23 | 52 | 262 | 261 | 0 | 57 | 0 | 0 | 2 |
[22] † Carrolla craddocki Last Modified in 07/20/23 | 119 | 211 | 211 | 0 | 40 | 0 | 0 | 2 |
[23] † Brachydectes newberryi Last Modified in 07/20/23 | 14 | 327 | 326 | 0 | 30 | 0 | 0 | 2 |
[24] † Greererpeton burkemorani Last Modified in 07/20/23 | 15 | 338 | 337 | 0 | 18 | 0 | 0 | 2 |
[25] † Seymouria baylorensis Last Modified in 07/20/23 | 16 | 341 | 338 | 0 | 16 | 0 | 0 | 2 |
[26] † Limnoscelis paludis Last Modified in 07/20/23 | 17 | 335 | 334 | 0 | 19 | 0 | 0 | 2 |
[27] † Branchiosauridae Last Modified in 07/20/23 | 208 | 156 | 154 | 0 | 8 | 0 | 0 | 2 |
[28] † Micromelerpetontidae Last Modified in 07/20/23 | 212 | 152 | 151 | 0 | 7 | 0 | 0 | 2 |
[29] † Tersomius texensis Last Modified in 07/20/23 | 158 | 212 | 206 | 0 | 6 | 0 | 0 | 2 |
[30] † Ecolsonia cutlerensis Last Modified in 07/20/23 | 208 | 159 | 157 | 0 | 5 | 0 | 0 | 2 |
[31] † Acheloma spp. Last Modified in 07/20/23 | 66 | 293 | 293 | 0 | 11 | 0 | 0 | 2 |
[32] † Eryops megalocephalus Last Modified in 07/20/23 | 54 | 305 | 304 | 0 | 12 | 0 | 0 | 2 |
[33] † Doleserpeton annectens Last Modified in 07/20/23 | 59 | 298 | 296 | 0 | 15 | 0 | 0 | 2 |
[34] Caudata Last Modified in 07/20/23 | 95 | 251 | 227 | 0 | 48 | 0 | 0 | 2 |
[35] Anura Last Modified in 07/20/23 | 112 | 216 | 206 | 0 | 52 | 0 | 0 | 2 |
[36] † Albanerpetontidae Last Modified in 07/20/23 | 214 | 131 | 130 | 0 | 26 | 0 | 0 | 2 |
[37] † Micropholis stowi Last Modified in 07/20/23 | 86 | 284 | 275 | 0 | 9 | 0 | 0 | 2 |
[38] † Eoscopus lockardi Last Modified in 07/20/23 | 90 | 277 | 272 | 0 | 8 | 0 | 0 | 2 |
[39] † Tambachia trogallas Last Modified in 07/20/23 | 167 | 197 | 196 | 0 | 7 | 0 | 0 | 2 |
[40] † Triadobatrachus massinoti Last Modified in 07/20/23 | 231 | 112 | 108 | 0 | 31 | 0 | 0 | 2 |
[41] † Gerobatrachus hottoni Last Modified in 07/20/23 | 180 | 184 | 184 | 0 | 6 | 0 | 0 | 2 |
[42] † Platyrhinops lyelli Last Modified in 07/20/23 | 101 | 261 | 260 | 0 | 9 | 0 | 0 | 2 |
[43] † Amphibamus grandiceps Last Modified in 07/20/23 | 200 | 168 | 168 | 0 | 2 | 0 | 0 | 2 |
[44] † Lethiscus stocki Last Modified in 07/20/23 | 62 | 279 | 278 | 0 | 30 | 0 | 0 | 2 |
[45] † Coloraderpeton brilli Last Modified in 07/20/23 | 76 | 261 | 259 | 0 | 35 | 0 | 0 | 2 |
[46] † Edops craigi Last Modified in 07/20/23 | 103 | 252 | 252 | 0 | 15 | 0 | 0 | 2 |
[47] † Quasicaecilia texana Last Modified in 07/20/23 | 211 | 141 | 141 | 0 | 18 | 0 | 0 | 2 |
[48] † Captorhinus laticeps Last Modified in 07/20/23 | 15 | 317 | 316 | 0 | 39 | 0 | 0 | 2 |
[49] † Petrolacosaurus kansensis Last Modified in 07/20/23 | 65 | 284 | 284 | 0 | 21 | 0 | 0 | 2 |
[50] † Ophiacodon uniformis Last Modified in 07/20/23 | 10 | 334 | 334 | 0 | 26 | 0 | 0 | 2 |
[51] † Baphetes spp. Last Modified in 07/20/23 | 136 | 226 | 226 | 0 | 8 | 0 | 0 | 2 |
[52] † Eucritta melanolimnetes Last Modified in 07/20/23 | 164 | 199 | 199 | 0 | 7 | 0 | 0 | 2 |
[53] † Llistrofus pricei Last Modified in 07/20/23 | 125 | 226 | 226 | 0 | 19 | 0 | 0 | 2 |
[54] † Aletrimyti gaskillae Last Modified in 07/20/23 | 86 | 255 | 255 | 0 | 29 | 0 | 0 | 2 |
[55] † Dvellecanus carrolli Last Modified in 07/20/23 | 107 | 237 | 237 | 0 | 26 | 0 | 0 | 2 |
[56] † Rhynchonkos stovalli Last Modified in 07/20/23 | 105 | 239 | 239 | 0 | 26 | 0 | 0 | 2 |
[57] † Dimetrodon spp. Last Modified in 07/20/23 | 28 | 314 | 314 | 0 | 28 | 0 | 0 | 2 |
[58] † Opisthodontosaurus carrolli Last Modified in 07/20/23 | 235 | 123 | 123 | 0 | 12 | 0 | 0 | 2 |
Project views
type | number of views | Individual items viewed (where applicable) |
Total project views | 4994 | |
Matrix views | 211 | Matrix landing page (204 views); Pardo et al 2017 (7 views); |
Media views | 1321 | Media search (361 views); M890374 (70 views); M890375 (68 views); M890376 (70 views); M890377 (71 views); M890378 (67 views); M890379 (66 views); M890380 (67 views); M890381 (67 views); M890382 (69 views); M890383 (68 views); M890384 (67 views); M890385 (72 views); M890386 (70 views); M890387 (68 views); |
Documents list | 140 | |
Project overview | 207 | |
Taxon list | 1382 | |
Views for media list | 143 | |
Bibliography | 111 | |
Specimen list | 1479 |