Paleo Profile: Pulanesaura eocollum

Name: Pulanesaura eocollum

Meaning: Pulanesaura is a combination of Sesotho and Latin meaning “rain-maker lizard”, while eocollum means “dawn neck” in honor of the dinosaur’s place as one of the earliest sauropods.

Age: Early Jurassic, around 191 to 183 million years ago.

Where in the world?: South Africa

What sort of critter?: One of the earliest sauropod dinosaurs.

Size: Estimated at about 26 feet long.

How much of the creature’s body is known?: Teeth ribs, vertebrae, part of the hips, and elements of the limbs from at least two individuals.

The known skeletal elements of Pulanesaura. From McPhee et al., 2015.
The known skeletal elements of Pulanesaura. From McPhee et al., 2015.


Claim to fame:

When 20th century paleontologists sifted through the fossil record for exceptional, finely-graded examples of evolutionary change, they didn’t look to dinosaurs. The saurians had box-office value for museums, sure, but they were too weird and too spread out along the prehistoric timeline to let researchers really see the “tempo and mode” of evolution. Thankfully, those days are behind us. Birds can now be called dinosaurs thanks to a dazzling and ever-increasing array of feathery fossils chipped from the rock, and, thanks to a spate of discoveries in Early Jurassic stone, paleontologists are getting a detailed look at the origins of the largest animals to ever walk the Earth.

Supersaurus. Argentinosaurus. Futalognkosaurus. These, among others, were the largest dinosaurs of all time – the long-necked, tiny-headed, herbivorous sauropods. But their ancestors were quite different. Referred to as sauropodomorphs, these animals were much smaller, often walked on two legs rather than four, and had significantly shorter necks. A slew of species gave paleontologists an outline of how scurrying little plant-eaters turned into lumbering giants, but it has only been recently that dinosaurs with the transitional features to document the shift have been found. The latest, described by University of Witwatersrand paleontologist Blair McPhee and colleagues, is Pulanesaura eocollum.

Even though McPhee and colleagues only had scattered elements to work with, they were able to discern that Pulanesaura was different from related dinosaurs living at the same time and in the same place. The sauropodomorph Aardonyx was found less than a mile away, for example, and another genus of these herbivores – Arcusaurus – was found at the edge of the same quarry. While these dinosaurs walked on two legs and had relatively stiff necks, the anatomy of the forelimb bones of Pulanesaura suggest it was a four-on-the-floor dinosaur, and its neck bones hint at a greater degree of flexibility than in its neighbors. This, McPhee and coauthors write, might mean that competition for greens drove some sauropodomorph dinosaurs to evolve a different posture and lifestyle that let them browse high and low. While not the very first sauropod, Pulanesaura marks the early days of a body plan that would last for over 100 million years more.

For more, read study author Matt Bonnan’s post about this new dinosaur.

Reference:

McPhee, B., Bonnan, M., Yates, A., Neveling, J., Choiniere, J. 2015. A new basal sauropod from the pre-Toarcian Jurassic of South Africa: evidence of niche-partitioning at the sauropodomorph-sauropod boundary? Scientific Reports. doi: 10.1038/srep13224

Previous Paleo Profiles:

Atychodracon megacephalus
Sefapanosaurus zastronensis
Huanansaurus ganzhouensis
Zhenyuanlong suni
Lepidus praecisio
Nothronychus graffami

Ganguroo robustiter
Vulpes mathisoni

Ichibengops munyamadziensis

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