Secret of sex buried in a museum

By / 20th of October, 2014

THE widely-reported news that a South Australian scientist has stumbled across the earliest evidence of male:female penetrative sex thanks to a fossil gathering dust in a Estonian museum is not only important for the study of evolution but also proves that museums still play an essential role in science. 

The discovery has opened an entirely new chapter in the study of how and when sex evolved in our earliest vertebrate ancestors. 

Professor John Long is Strategic Professor in Palaeontology at Flinders University, and was studying fossils of an ancient Scottish ‘Placoderm’ fish known as Microbrachius dicki during 2013.

This is an argument as to why museums should continue to be well funded and well supported

“I was working in a laboratory with an 85-year old paleontologist, and she gave me a old box with Placoderm fossils in it,” said Professor Long. 

“I saw a tiny bone, and realised it was a clasper, a male sexual organ.”

Following his discovery, Professor Long and colleagues – including Dr Mike Lee of the South Australian Museum – conducted in-depth analysis of other Microbrachius dicki fossils, including both male and female specimens.

In their scientific paper published today in the journal Nature, they report that male fish of this species had protruding L-shaped bones called claspers that were used to transfer sperm to females, while females had small paired bones to lock the male organs in place for mating.

The fossils are dated to 385 million years ago, placing copulation much earlier along the evolutionary timeline than other evidence supported.

“Basically it’s the first branch off the evolutionary tree where these reproductive strategies started,” said Professor Long.

The research shows just how important the study of fossils can be, not just for understanding the bony structures of extinct animals, but also to gain insights into the origins of complex physiologies and behaviors in our distant ancestors.

“This is one of the most amazing things about paleontology,” said Professor Long. “Sometimes it’s working in the field, and sometimes it can involve looking at samples in museums.”

“Museums are rich resources, and big discoveries can be made if the right experts can get access to these specimens,” he said. 

“This is an argument as to why museums should continue to be well funded and well supported.”

Professor Mike Lee from the South Australia Museum says it’s a good example of how research can bare rich rewards.

“Blue sky research with no immediate applications can turn out to be surprisingly relevant,” he said.

The particular fossils used in this study will be on display at the South Australian Museum from October 20 2014 and a more in-depth article by John Long from The Conversation is available.

Key contacts

Professor John Long Strategic Professor in Palaeontology Flinders University
61 08 8201 2267