Dr. Marples and His Penguins

Dr. Brian J. Marples was one of the great contributors to the study of penguin evolution during the 20th century.  Marples was a true polymath, one of the all-purpose scientists of yesteryear who are so rare today.  He studied and published on many disparate topics including spiders from throughout the South Pacific, the life habits of New Zealand birds, the circulatory systems of fish, extinct whale brain endocasts, and of course fossil penguins.

Limestone cliffs in North Canterbury, New Zealand - home of spiders, resting place of ancient whales and penguins.

Marples actually found many of the penguin fossils he studied while searching for spiders, the main focus of much of his life’s work.  A spider expert, he had a particular interest in trapdoor spiders.  These spiders are common in rocky environments, including greensand and limestone cliffs (like those above).  These spiders inhabit burrows with home-made “doors” that they leap from to ambush and capture passing prey.  Traveling around the vicinity of Duntroon, a settlement in the South Island, Marples collected trapdoor spiders in jars as he worked on mapping their geographical distributions and describing their anatomy. In the process, he regularly ran into fossil bone – often from penguins and whales.  According to accounts (see link below), he and his students often livened up the Duntroon Hotel’s bar after collecting expeditions.  I’ve lifted my feet to the fire in the same staff lounge Marples no doubt frequented at the University, but I can only guess at the boisterous activities generated by placing pints on top of the table and jars of spiders underneath.

The fossils collected from the Duntroon cliffs revolutionized our understanding of ancient penguins.  Previously, many fossil penguin bones had been collected but associated skeletons from individual animals were very rare.  Marples penguins gave us the first glimpse at what the skeletons large Oligocene penguins of 25 million years past might have looked like whole (with the notable exception that nearly all the skull bones were lost).  In paleontology, it is common practice to name newly discovered species in honor of someone who has contributed to the discovery or study of that species – for example the person who found the fossil, a volunteer who helped with the field or museum work, or a respected expert on the group of interest.  Marples has been recognized three times in this manner.

Interestingly, Dr, Marples himself actually described the fossils that bear his name.  It is of course in bad taste (and in fact forbidden) to name a fossil after yourself.  Marples certainly did not attempt such a crass act.  At the time he found the penguins, he believed two of them belonged to the already-named species Palaeeudyptes antarcticus and Platydyptes novaezealandiae, and that the third represented a new species of the South American genus Palaeospheniscus – Palaeospheniscus novaezealandiae.   This later turned out to be an overly conservative interpretation.   The first two fossils were later found to be distinct species and the third found not to belong in the genus Palaeospheniscus.

George Gaylord Simpson later changed the genus name to Marplesornis (“Marples’ bird”) in recognition of these differences, and in honor of Marples’ contributions to penguin paleontology.  The other two fossils also bear Marples-based species honorifics – Pierce Brodkorb dubbed one set of large penguin fossils from the Burnside Mudstone Quarry near Otago University Palaeeudyptes marplesi and  Simpson named a smaller set of remains from cliffs of  Duntroon Platydyptes marplesi. Palaeeudyptes marplesi was a large, stout fellow though unfortunately we have only a few limb bones and vertebrae.  Platydyptes marplesi, seen below, was a moderate sized penguin with really wide flipper bones – the genus name means “wide diver” and has turned out to be one of the more common penguins of the Oligocene of New Zealand.  A unique arrangement of the articulation between the wing and shoulder suggests it was a strong underwater flier, but the mechanics are still under study.

Holotype of Platydyptes marplesi, one of Marples penguins. The limestone block holds most of the pectoral girdle and wings, which have been exposed at the surface.

Marplesornis novaezealandiae is perhaps the most interesting of the three species.  According to analyses of fossil penguin relationships, Marplesornis represents the last lineage of penguins to branch off the evolutionary tree before the radiation of modern penguins began. This penguin was about the size of a living King Penguin and had large spaces for the jaw muscles on the back of the skull, like modern penguins that eat fish.  It supports the hypothesis that only once modern penguins had evolved did the group begin experimenting with more krill-heavy planktonic diets.

So, those are the three penguins.   For more on spiders and other facets of Dr. Marple, check out the Vanished World website: http://www.vanishedworld.co.nz/spiders.htm