Let’s put tiny eyeballs into Brachydectes

This post was updated February 8, 2017 with a new identification of several skull bones that did not change the tree topology. Brachydectes still nests with Eocaecilia. 

Further updated March 18, 2017 with new skull bone identities for Brachydectes

Carroll RL 1967. An Adelogyrinid Lepospondyl Amphibian from the Upper Carboniferous: Canadian Journal of Zoology 45(1):1-16.
Carroll RL and Gaskill P 1978. The order Microsauria. American Philosophical Society, Philadelphia, 211 pp.
Cope ED 1868. Synopsis of the extinct Batrachia of North America. Proc Acad Nat Sci 20: 208–221. doi: 10.5962/bhl.title.60482
Jenkins FA and Walsh M 1993. An Early Jurassic caecilian with limbs. Nature 365: 246–250.
Jenkins FA, Walsh DM and Carroll RL 2007. Anatomy of Eocaecilia micropodia, a limbed caecilian of the Early Jurassic. Bulletin of the Museum of Comparative Zoology 158(6): 285-366.
Marjanović D and Laurin M 2013. The origin(s) of extant amphibians: a review with emphasis on the “lepospondyl hypothesis”. Geodiversitas 35 (1): 207-272. http://dx.doi.org/10.5252/g2013n1a8
Pardo JD and Anderson JS 2016. Cranial Morphology of the Carboniferous-Permian Tetrapod Brachydectes newberryi (Lepospondyli, Lysorophia): New Data from µCT. PLoS ONE 11(8): e0161823. doi:10.1371/journal.pone.0161823. online here.
Wellstead C F 1991. Taxonomic revision of the Lysorophia, Permo-Carboniferous lepospondyl amphibians. Bulletin of the American Museum of Natural History 209: 1–90.








2 thoughts on “Let’s put tiny eyeballs into Brachydectes

  1. A LTF is unknown in most lepospondyls — except Cacops. The Cacops LTF is posterior to the squamosal.

    That’s because it’s not a LTF – it’s neither homologous nor analogous to those that most amniotes keep their jaw muscles in. It’s homologous to the spiracle (the first gill slit) and probably functioned as a middle ear for the reception of airborne sound (adult dissorophids were terrestrial). The tabular and the quadrate have grown around it, presumably to support a large eardrum.

    BTW, Cacops is a temnospondyl, not a lepospondyl. Among lepospondyls, however, various embayments of the ventral margin of the skull behind the maxilla occur a few times, and apparently phylogenetically close to Brachydectes.

    Some of the tracings above have the supraoccipital contacting the parietals and separating or nearly separating the postparietals. Which is correct?

    All of them. It’s individual variation.

  2. David, can you send me a temnospondyl that will attract Cacops away from Amphibamus? That’s why I put Eryops in the LRT, but it was not attractive enough. Wiki also reports a Cacopes/Amphibamus alliance, but what do they know…

    Interesting about the spiracle issue…

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