The cranial endocast of the Upper Devonian dipnoan Chirodipterus australis
- Published
- Accepted
- Subject Areas
- Evolutionary Studies, Paleontology
- Keywords
- endocast, Dipnoi, Devonian, Sarcopterygii, Chirodipterus, inner ear
- Copyright
- © 2018 Henderson et al.
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2018. The cranial endocast of the Upper Devonian dipnoan Chirodipterus australis. PeerJ Preprints 6:e26591v1 https://doi.org/10.7287/peerj.preprints.26591v1
Abstract
One of the first endocasts of a dipnoan (lungfish) to be realised was that of the Upper Devonian taxon Chirodipterus australis. This early interpretation was based on observations of the shape of the cranial cavity alone and was not based on a natural cast or 'steinkern' nor from serial sectioning. The validity of this reconstruction is therefore questionable and continued reference to and use of this interpretation in analyses of sarcopterygian cranial evolution runs the risk of propagation of error. Here we describe a new detailed anatomical description of the endocast of Chirodipterus australis and show that it exhibits a suite of characters more typical of Lower and Middle Devonian dipnoan taxa. Notably, the small utricular recess is unexpected for a taxon of this age, whereas the ventral expansion of the telencephalon is more typical of more derived taxa. The presence of such 'primitive' characters in C. australis supports its relatively basal position as demonstrated in the most recent phylogenies of Devonian Dipnoi.
Author Comment
This is a submission to PeerJ for review.
Supplemental Information
Comments of the character matrix of Clement et al., (2016) and Supplementary Figure 1
Single most parsimonious tree using stepwise addition with 10,000 random addition sequence replicates holding five trees at each step, with tree bisection and reconnection (TBR) enabled. Length = 36, CI = 0.639, RI = 0.667. Values at nodes are for Bremer indices.