Paleontologists uncover three new species of extinct walruses in Orange County

Paleontologists uncover three new species of extinct walruses in Orange County

Thousands and thousands of years in the past, within the heat Pacific Ocean off the coast of Southern California, walrus species with out tusks lived abundantly.

Paleontologists uncover three new species of extinct walruses in Orange County
Credit score: Jacob N. Biewer et al., 2020

However in a brand new research, Cal State Fullerton paleontologists have recognized three new walrus species found in Orange County and one of many new species has “semi-tusks” — or longer tooth.

The opposite two new species haven’t got tusks and all predate the evolution of the lengthy iconic ivory tusks of the modern-day walrus, which lives within the frigid Arctic.

The researchers describe a complete of 12 specimens of fossil walruses from Orange, Los Angeles and Santa Cruz counties, all estimated to be 5 to 10 million years outdated. The fossils characterize 5 species, with two of the three new species represented by specimens of males, females and juveniles.

Their analysis, which provides insights on the dental and tusk evolution of the marine mammal, was printed at this time within the Journal of Vertebrate Paleontology.

Geology graduate Jacob Biewer, and his analysis adviser James F. Parham, affiliate professor of geological sciences, are authors of the research, based mostly on fossil cranium specimens.

Parham and Biewer labored with Jorge Velez-Juarbe, an professional in marine mammals on the Pure Historical past Museum of Los Angeles County, who’s a co-author of the paper. Velez-Juarbe is a former postdoctoral scholar in Parham’s lab and has collaborated on different CSUF fossil analysis initiatives. Parham is a analysis affiliate on the museum, which offers analysis alternatives for him and his college students.

The researchers teamed to review and describe the anatomy of the specimens, most of that are a part of the museum’s assortment.

“Orange County is crucial space for fossil walruses on the planet,” mentioned Biewer, first writer of the paper who performed the analysis for his grasp’s thesis. “This analysis reveals how the walruses developed with tusks.”

At the moment, there is just one walrus species and its scientific title is Odobenus.

For the brand new species present in Orange County, the researchers named the semi-tusked walrus, Osodobenus eodon, by combining the phrases Oso and Odobenus. One other is known as Pontolis kohnoi in honor of Naoki Kohno, a fossil walrus researcher from Japan. Each of those fossils had been found within the Irvine, Lake Forest and Mission Viejo areas.

Osodobenus eodon and Pontolis kohnoi are each from the identical geological rock layer because the 2018 research by Parham and his college students of one other new genus and species of a tuskless walrus, Titanotaria orangensis, named after CSUF Titans. These fossils had been discovered within the Oso Member of the Capistrano Formation, a geological formation close to Lake Forest and Mission Viejo.

The third new walrus species, Pontolis barroni, was present in Aliso Viejo, close to the 73 Toll Street. It’s named after John Barron, a retired researcher from the united statesGeological Survey and world professional on the rock layer the place the specimens had been discovered, Parham mentioned.

Evaluation of those specimens present that fossil walrus tooth are extra variable and complicated than beforehand thought-about. Many of the new specimens predate the evolution of tusks, Parham mentioned.

“Osodobenus eodon is essentially the most primitive walrus with tusk-like tooth,” Parham mentioned. “This new species demonstrates the necessary position of feeding ecology on the origin and early evolution of tusks.”

Biewer defined that his work targeted on getting a greater understanding of the evolutionary historical past of the walrus with reference to its tooth.

“The significance of dental evolution is that it reveals the variability inside and throughout walrus species. Scientists assumed you might determine sure species simply based mostly on the tooth, however we present how even people of the identical species might have variability of their dental setup,” mentioned Biewer, who earned a grasp’s diploma in geology in 2019.

“Moreover, everybody assumes that the tusks are crucial tooth in a walrus, however this analysis additional emphasizes how tusks had been a later addition to the historical past of walruses. The vast majority of walrus species had been fish eaters and tailored to catching fish, relatively than utilizing suction feeding on mollusks like fashionable walruses.”

Biewer, now a paleontologist within the Modesto space, additionally examined whether or not local weather adjustments within the Pacific Ocean had an impression on historic walruses. His work suggests {that a} rise in water temperature helped to spice up vitamins and planktonic life, and performed a job within the proliferation of walruses about 10 million years in the past, which can have contributed to their variety.

Supply: Taylor & Francis [November 16, 2020]

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