Balanerpeton and Caerorhachis

Caerorhachis bairdi (Holmes and Carroll 1977, Ruta, Milner and Coates 2001; Serpukhovan, Early Carboniferous, 325 mya; ~20cm in length) was originally considered a primitive edopoid temnospondyl with uncertain affinities. Here it nests between Balanerpeton and more derived lepospondyls. It has 31 presacral vertebrae with the protoreptilian structure of primitive anthracosaurs and the skull has no lateral line canals.

Balanerpeton woodi (Milner and Sequeira 1994; Viséan, Early Carboniferous, 340 mya; ~50cm in length) was derived from an earlier sister to Utegenia and gave rise to all other lepospondyls including microsaurs and extant amphibians. This taxon demonstrates that Utegenia cousins were coeval to or preceded the Viséan.

The stapes was narrow and the back of the skull likely bore a tympanic membrane for more acute hearing. The skull did not possess a lateral line system. The ribs were small and straight. Five fingers were present (see below).

Cope ED 1865. On Amphibamus grandiceps, a new Batrachian from the Coal Measures: Proceedings of the National Academy of Science, 1865, p. 134-137.

Holmes R and Carroll R 1977. A temnospondyl amphibian from the Mississippian of Scotland. Bulletin of the Museum of Comparative Zoology. 147: 489–511.

Milner AR and Sequeira SEK 1994. The temnospondyl amphibians from the Viséan of East Kirkton, West Lothian, Scotland. Transactions of the Royal Society of Edinburgh: Earth Sciences 84:331-361

Moodie RL 1916. Journal of The coal measures Amphibia of North America. Carnegie Institution of Washington #238. 222 pp.

Ruta M, Milner AR and Coates MI 2001. The tetrapod Caerorhachis bairdi Holmes and Carroll from the Lower Carboniferous of Scotland. Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 92 (3): 229–261.

Wyman J 1857. On a batrachian reptile from the coal formation. Proceedings of the American Association for the Advancement of Science, 10th Meeting, 172-173.

wiki/Amphibamus
wiki/Balanerpeton
wiki/Caerorhachis

Reptilomorpha

Caerorhachis

Seymouriamorpha

Protoreptilia