My new paper: A redescription of Pseudaptenodytes macraei


Whilst my PhD research has been keeping me very busy this year, I've managed to dedicate a little bit of time (weeknights and weekends) to continuing my research on Australian fossil penguins. At the end of last week I was very pleased to see that one of those research projects published, making it paper number four for me.

The paper is entitled “Redescription of the Miocene penguin Pseudaptenodytes macraei Simpson (Aves: Sphenisciformes) and redefinition of the taxonomic status of ?Pseudaptenodytes minor Simpson” and it was published online in the journal Alcheringa (the print version will be published in later this year).

A typical late Miocene beach in southeastern Australia might have looked something like this beautiful reconstruction by Peter Trusler. In the bottom left hand corner there are some  Pseudaptenodytes macraei enjoying their day at the beach...

A typical late Miocene beach in southeastern Australia might have looked something like this beautiful reconstruction by Peter Trusler. In the bottom left hand corner there are some Pseudaptenodytes macraei enjoying their day at the beach...

As the title suggests I’ve redescribed the holotype of an Australian fossil penguin known as Pseudaptenodytes macraei. This species lived 6–7.5 million years ago in Victoria, Australia. It would have been approximately the same size as the living king penguin (80–90 cm tall). It is known almost entirely based on the holotype left humerus, although other material has been referred to the taxa the fact they are different elements means there is no basis for comparison at present.

Pseudaptenodytes macraei was named and originally described in 1959 by one of the giants of 20th century vertebrate palaeontology, George Gaylord Simpson. Despite being primarily known for his work on fossil mammals, he also had a love for fossil penguins and essentially dominated the field from 1950–1980. So why did I feel the need to go back and redescribe this taxon given that someone as eminent as Simpson had already done so? Well, there were several reasons: 1) the description Simpson gave was very brief and lacked the detail that would be given in a modern description; 2) related to the previous point, the terminology used today is a lot more consistent, rather than the varying terms used in the past; 3) we now have a much better idea of the age of the specimen (6–7.5 Ma) than when the it was originally described; 4) finally, there have been lots of new discoveries since the original description, which allows us to compare this specimen to many more taxa.

P. macraei post fig 1(2)

The holotype of Pseudaptenodytes macraei in (A) dorsal, (B) ventral and (C) caudal views. Abbreviations: cdp, crista deltopectoralis; cmc, curved margo cranialis; fn, foramen nutriens; ft, fossa tricipitalis; hp, humeral plexus; ic, incisura capitis; iims, impressio insertii m. supracoracoideus imp, impressio m. pectoralis; sft, secondary fossa tricipitalis; tv, tuberculum ventrale. Scale bars = 10 mm. Image from Park 2014

So what this paper represents is a more detailed, up-to-date redescription of the holotype left humerus, in addition to comparisons with all post-Oligocene taxa. I have however refrained from putting a phylogenetic analysis in the paper as P. macraei is included in the phylogeny I have constructed for a bigger paper looking at Australian fossil penguins, which has been in the pipeline for some time (representing my honours thesis plus further research) and have opted to keep phylogenetic discussions to that paper.

What makes P. macraei a unique species then? My studies have found two distinguishing features: 1) the ventral partition of the tricipital fossa possess a distinctly flattened elliptical shape 2) the cranial margin of the humerus is curved rather than possessing a preaxial angle. Another outcome of the paper is that Pseudaptenodytes should now be considered as monogeneric. This is due to the holotype of Pseudaptenodytes minor, the previous other species from the genus (also named by Simpson in 1970), being based on really quite paltry material that does not permit autapomorphies (or any comparisons at all really) to be made.

Figure showing the distinguishing features of Pseudaptenodytes macraei. (A) the ventral partition of the tricipital fossa (B) the curved cranial margin. Scale bars = 10 mm. Image from Park 2014

Figure showing the distinguishing features of Pseudaptenodytes macraei. (A) the ventral partition of the tricipital fossa (B) the curved cranial margin. Scale bars = 10 mm. Image from Park 2014

Whilst it may not be the most earth shattering paper ever published, it still feels great to get another one out there and add another publication to my CV. Hopefully, in the next few months I can get at least another one or two of the three other penguin papers I’m currently working on submitted. And that’s without even mentioning my PhD research! Busy times!


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