Fig 1.
Neural arches in white, pleurocentra in dark gray, intercentra in light gray, spinal canal in packed gray circles, notocanal in striped bars. Left column; rhachitomous vertebra from Eryops megacephalus (FMNH 117) (A) and stereospondylous vertebra from Mastodonosaurus giganteus (AMNH 2994) (B), vertebrae in caudal view. Right column: variations on rhachitomous vertebrae seen in Temnospondyli; (a) Rhachitomous; (b) Reverse Rhachitomous; (c) Stereospondylous; (d) Plagiosaurid. White arrows point to prezygapophyses, black arrows point to postzygapophyses.
Table 1.
Museums used in this study.
Fig 2.
Morphospace for temnospondyl neural arches.
Principle component analysis shows vertebral type distribution. A: “consensus” data set; B: “most recent” data set. Dashed circles represent changes between A and B. Convex hulls are grouped according to a priori habitat. Grey shapes are theoretical neural arches representing at a particular point in PC1 and PC2. Shape of the point represents the vertebral type.
Table 2.
Shape-ANOVA results.
Table 3.
Phylogenetic-ANOVA results.
Fig 3.
Morphospace for temnospondyl intercentra.
Principle component analysis displaying vertebral type distribution. Convex hulls are grouped according to a priori habitat. A: “consensus” data set; B: “most recent” data set. Dashed circles represent changes between A and B. Grey shapes are theoretical intercentra representing at a particular point in PC1 and PC2. Shape of the point represents the vertebral type.
Fig 4.
Phylogeny and habitat of temnospondyls.
Tip colors are pooled prior probabilities for clades as gathered from literature and paleobiology database (PBDB; Supplementary Information). Node colors display posterior probabilities calculated from the best-fit (OU; terrestrial-semiaquatic-aquatic) mode in Ancthresh. Thick lines represent stratigraphic range. Reconstructions borrowed with permission from Nobu Tamura.
Fig 5.
Traces of neural arch and intercentra shape convergence characterized by environment.
Top row: Reconstructions borrowed with permission from Nobu Tamura. From left to right: Cacops aspidephorus Paracyclotosaurus davidi, Archegosaurus decheni. Middle row: a) Cacops aspidephorus (ancestrally terrestrial); b) Paracyclotosaurus davidi (ancestrally semiaquatic); c) Metoposaurus diagnosticus (ancestrally aquatic). Bottom row: d) Lydekkerina huxleyi (secondarily terrestrial); e) Mastodonsaurus giganteus (variation on semiaquatic form, note no secondarily semiaquatic taxa were reported from this study); f) Archegosaurus decheni (secondarily aquatic).