#plagiaulacida

[obscurefossils]

Iberica hahni

Iberica was a genus of multituberculate mammal from the Early Cretaceous Period. Its type and only species is I. hahni. Known specimens were found in the El Castellar Formation in Galve, Spain. While the fossils assigned to Iberica have been known since the 1960s, they were not officially named until 2011.

The name Iberica comes from the fossil's location on the Iberian Peninsula. The specific name hahni was named in honor of Gerhard and Renate Hahn for their research on Iberian Peninsula multituberculates.

Known fossils of I. hahni include seven P1/3s (premolars), which are the type specimen, as well as the referred material of a P4 fragment (premolar) and two M2s (molars). Its autapomorphies include the four cusps on its premolars, as compared to three cusps from related genera, as well as cuspules on the mesial and distal margins.

The material assigned to I. hahni, especially the referred P4 and M2s, cannot be certainly assigned to either Eobaataridae or Plagiaulacidae. The type premolars are similar to that of Parabolodon elongatus and Eobaatar? pajaronensis. The P4 fragment is also very similar to that of Cheruscodon balvensis. The tentative assignment to Eobaataridae seems somewhat unlikely.

References: Original description by Ainara Badiola, José Ignacio Canudo, and Gloria Cuenca-Bescós; cladistic assessment by Thomas Martin et al.

Wikipedia article: Iberica hahni

[dendroica]

160-Million-Year-Old Fossil of an Omnivore

The fossil, found in Liaoning Province in northeastern China, is the earliest known skeletal fossil of a multituberculate, and offers new insight into this mammal group’s incredible success. Multituberculates thrived alongside dinosaurs for more than 100 million years and then outlived them for 30 million years before becoming extinct, making way for rodents.

The newly described species, Rugosodon eurasiaticus, had highly ornamented teeth, with many wrinkles and creases. This is a sign that multituberculates started out as omnivores, researchers said.

“It has lots of small ridges and grooves that are densely packed,” said Zhe-Xi Luo a paleontologist at the University of Chicago and one of the study’s authors. “In modern rodents this is related to a diet supplemented by small insects and small vertebrates.”

Over time, many multituberculates evolved to become herbivores, an adaptation that helped them thrive. The researchers also discovered that the rodentlike animal had mobile and flexible anklebones, suggesting that it was a fast runner that primarily lived on the ground.

(via NYTimes.com)