Dendrerpeton gets the DGS treatment

Figure 1. GIF movie of Dendrepeton fossil in situ showing original interpretation with intertemporal and contact of the prefrontal and postfrontal. Below: DGS tracing and new interpretation without the intertemporal and prefrontal/postfrontal contact.

Figure 1. GIF movie of Dendrepeton fossil in situ showing original interpretation with intertemporal and contact of the prefrontal and postfrontal. Below: DGS tracing and new interpretation without the intertemporal and prefrontal/postfrontal contact. Fossil images from Holmes et al. 1998.

Dendrerpeton acadianum (Owen 1853; Holmes, Carroll and Reisz 1998; Bashkirian, Carboniferous ~318 mya; ~10 cm in length; YPM VP 005895, BMNH R4158, RM 2.1121) was derived from a sister to Amphibamus and phylogenetically preceded Acheloma and Cacops in the large reptile tree (LRT).

Schoch and Miller 2014 considered this specimen conspecific with Dendrysekos helogenes (Steen 1934).

Figure 2. Dendrerpeton without raised orbits from Holmes et al. 1998.

Figure 2. Dendrerpeton without raised orbits from Holmes et al. 1998. These authors had firsthand access to the specimen, yet missed several details revealed by second hand access to published photos.

Overall larger than Amphibamus, 
the skull of Dendrerpeton was narrower, the rostrum longer, the nares more widely separated. The skull bones were highly sculptured.

Distinct from earlier interpretations
by Holmes, et al. 1998 (Figs. 1,2), the orbit of Dendrerpeton was raised above the skull roof, the prefrontal did not contact the postfrontal, the palatine was exposed laterally and the intertemporal was not present. These authors had firsthand access to the specimen, yet missed several details revealed by second hand access to published photos. DGS reveals where the puzzle pieces are simply by coloring them to segregate them, and trying the puzzle pieces until they fit.

At present these traits
nest Dendrerpeton close to Tersomius (Fig. 3) within the Lepospondyli.

Figure 3. Tersomius texensis, an amphibamid lepospondyl close to Dendrerpeton.

Figure 3. Tersomius texensis, an amphibamid lepospondyl close to Dendrerpeton. DGS colors have been applied over several bones.

References
Case EC 1910. New or little known reptiles and amphibians from thePermian (?) of Texas. Bulletin of the American Museum of Natural History 28, 163–181.
Holmes RB, Carroll RL and Reisz RR 1998. The first articulated skeleton of Dendrerpeton acadianum (Temnospondyli, Dendrerpetontidae) from the lower Pennsylvanian locality of Joggins, Nova Scotia, and a review of its relationships. Journal of Vertebrate Paleontology 18:64-79.
Maddin H, Fröbisch NB, Evans DC and Milner AR 2013. Reappraisal of the Early Permian amphibamid Tersomius texensis and some referred material. Comptes Rendus Palevol 12:447-461.
Moodie RL 1916. Journal of The coal measures Amphibia of North America. Carnegie Institution of Washington #238. 222 pp.
Owen R 1853. Notes on the above-described fossil remains. Quarterly Journal of the Geological Society of London 9:66-67
Schoch RR and Milner AR 2014. Temnospondyli I. Part 3A2 of Sues H-D, ed. Handbook of 6468 Paleoherpetology. Munich: Dr. Friedrich Pfeil.
Steen MC 1934. The amphibian fauna from the South Joggins, Nova Scotia. Proceedings of the Zoological Society of London 1934:465-504.
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/Dendrerpeton
wiki/Tersomius

 

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3 thoughts on “Dendrerpeton gets the DGS treatment

  1. DGS reveals where the puzzle pieces are simply by coloring them to segregate them, and trying the puzzle pieces until they fit.

    What it can’t do is account for plastic deformation of individual bones. The published photos of this specimen are nowhere near good enough to get a handle on that.

    BTW, this isn’t Dendrerpeton at all, let alone D. acadianum; it’s Dendrysekos. I recommend the non-stereospondyl temnospondyl volume of the Handbuch (Schoch & Milner 2014). You’d know this if you had read my preprint… :-)

    • I cited all the specimen numbers and the references. Why would I repeat the picture?

      …apart from the fact that it must be quite a hassle to get permission to reprint such a thing, let alone under a CC-BY license.

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