homehome Home chatchat Notifications


Newly described genus hints at the evolutionary roots of the giraffe

Long neck, long history.

Alexandru Micu
November 1, 2017 @ 8:15 pm

share Share

A new, extinct large giraffid genus has been described by Spanish researchers, offering a new glimpse into the evolutionary path of the long-necked herbivores.

Decennatherium.

Skeletal sketch, size comparison to modern human, and artist’s reconstruction of the newly described genus. 

Modern giraffes (Giraffa camelopardalis) stand out instantly, with their tall necks and bony osccicones — the horn-like protuberances on the giraffe’s head. By virtue of this alone, you could think they’ve had a completely different evolutionary path than other animals, but that’s not true. They’re part of a larger family of ruminants known as Giraffidae and their closest living relative is the okapi (Okapia johnstoni), which is a pretty regular looking animal.

However, knowing its family ties today doesn’t mean we know how the giraffe came to be. Researchers think that Giraffidae have been around since the Miocene epoch, with over 30 extinct species found and described up to now. A lack of fossilized skulls, the paper notes, has impeded biologists from establishing the evolutionary relationships between them.

Getting ahead

The new genus, named Decennatherium rex sp. nov., could help bridge some of those gaps in our understanding. It was described by a team led by María Ríos from the National Museum of Natural History, Spain from a fossilized skeleton that is “unusually” complete. Although not yet dated, stratigraphic position suggests the fossil originates sometime in the late Miocene.

The team performed a full phylogenetic analysis on Decennatherium and follow it up with the “the first phylogenetic reconstruction of the [Graffidae] group”. They report that the genus could represent the most basal branch (i.e. common ancestor) of a clade of now-extinct giraffid groups, and is likely the earliest-evolving example of the four osscicone layout seen today, with two over the eyes and two larger, ridged ones at the back of the head. This layout is shared by all species in the clade, lending weight to the hypothesis that Decennatherium is the extinct clade’s common ancestor or at least very close to it in evolutionary terms.

The clade includes Sivatheres, the largest known giraffid, and Samotheres, whose appearance was somewhere in between that of okapis and giraffes. Bryan Shorrocks, a professor in the Environment Department at the University of York, notes in his book The Giraffe: Biology, Ecology, Evolution and Behaviour that a subspecies of the latter, S. africanum, is a strong candidate as the ancestor of the modern giraffe.

The inclusion of the Decennatherium in the sivathere-samothere clade would extend its timespan back to the early Miocene and its range over the Iberian peninsula, the team notes, which would make it the most successful and long-lived clade among the giraffids.

The paper “Evolution and systematics of the late miocene spanish Giraffidae (Mammalia, Ruminantia, Pecora)” has been published on the scientific repository RODERIC.

share Share

Gardening Really Is Good for You, Science Confirms

Gardening might do more for your health than you think.

The surprising health problem surging in over 50s: sexually transmitted infections

Doctors often don't ask older patients about sex. But as STI cases rise among older adults, both awareness and the question need to be raised.

Kids Are Swallowing Fewer Coins and It Might Be Because of Rising Cashless Payments

The decline of cash has coincided with fewer surgeries for children swallowing coins.

Horses Have a Genetic Glitch That Turned Them Into Super Athletes

This one gene mutation helped horses evolve unmatched endurance.

Scientists Discover Natural Antibiotics Hidden in Our Cells

The proteasome was thought to be just a protein-recycler. Turns out, it can also kill bacteria

Future Windows Could Be Made of Wood, Rice, and Egg Whites

Simple materials could turn wood into a greener glass alternative.

Researchers Turn 'Moon Dust' Into Solar Panels That Could Power Future Space Cities

"Moonglass" could one day keep the lights on.

Ford Pinto used to be the classic example of a dangerous car. The Cybertruck is worse

Is the Cybertruck bound to be worse than the infamous Pinto?

Archaeologists Find Neanderthal Stone Tool Technology in China

A surprising cache of stone tools unearthed in China closely resembles Neanderthal tech from Ice Age Europe.

A Software Engineer Created a PDF Bigger Than the Universe and Yes It's Real

Forget country-sized PDFs — someone just made one bigger than the universe.