Telling the Boys from the Girls in Fossils – #365papers – 2017 – 88

#365papers for March 29, 2017

Mallon, 2017, Recognizing sexual dimorphism in the fossil record: Lessons from nonavian dinosaurs: Paleobiology, DOI:10.1017/pab.2016.51

What’s it about?

In paleontology, we define species by what they look like. This can be problematic if males and females of one species look markedly different from one another. Some authors have claimed to see sexual dimorphism, the difference in shape between males and females in a species, based on size. Here, the author shows that it is essentially impossible with the fossil record to make such determinations.

Why does it matter?

It’s important to avoid making claims that can’t be supported. The author here uses statistical means to show that prior claims aren’t as strong as originally thought and that caution should always be used when attempting to distinguish males from females in fossils.

Why did I read this?

Size is a big problem in paleontology. Sometimes the only provided distinction between species is the size, which to my mind is not often really acceptable. Sexual dimorphism could also lead to mis-identifying species, or naming two species when there really is only one. I was interested to know that none of the claims of sexual dimorphism that Mallon studied really stood up to rigorous analysis.

Published by paleololigo

Scientist (Paleontology, Geochemistry, Geology); Writer (Speculative and Science Fiction, plus technical and non-technical Science); Mom to great boy on the Autism spectrum; possessor of too many hobbies.

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