In honour of Canada Day, this week's blog post (delayed post since I'm in the field right now) covers the few (but notable) Canadian temnospondyls. Note that this is a brief, not a comprehensive history, considering there's quite a lot of articles spanning over 150 years and also that I wrote this in between a conference and packing for fieldwork (P.S. I'm in the field now, sorry about any errors or typos!).
The next substantial work to address Dendrerpeton was the review of Joggins amphibians by Margaret Steen in 1934. Steen provided thorough figures and descriptions of numerous specimens, many of which were previously unfigured or only generically figured. I won't go into too much detail here because a lot of it is the gory descriptive work and taxonomy that bores a lot of people, but it is really a great piece of work with a lot of good information in it that is still useful 85 years later. Steen redescribed a number of previously described taxa and updated their diagnoses and also named a few new ones, such as Dendrysekos helogenes, which is an important taxon but sparsely represented in the literature for reasons that will be explained in short below.
The taxonomy of Joggins temnospondyls is not a trivial issue. For one, the Joggins tetrapods include some of the oldest occurrences of various crown clades (e.g., temnospondyls) in continental North America. Secondly, whether there is a single rather morphologically variable taxon or a number of more morphologically constrained taxa is important for understanding the diversity and evolutionary history of temnospondyls at Joggins. The last point is that Dendrerpeton acadianum has long been utilized as the outgroup for many temnospondyl studies, but this has usually been based on the descriptions of the above two specimens that are now considered to belong to Dendrysekos helogenes (particularly the one described by Holmes et al., 1998). This is why more recent analyses now list D. helogenes as the outgroup, even though the coding and information remain the same as when it was listed as D. acadianum. Another look at the Joggins temnospondyls is certainly warranted, and a number of researchers, particularly in Canada (e.g., Jason Anderson, Hillary Maddin, Arjan Mann, and Jason Pardo) are diving back into collections to reassess the taxonomy of a lot of the Joggins tetrapods.
About the blog
A blog on all things temnospondyl written by someone who spends too much time thinking about them. Covers all aspects of temnospondyl paleobiology and ongoing research (not just mine).