Nabotherium: a new Anthracothere From Oligocene Paleogene Egypt With Interesting Dental Adaptations

A new anthracothere (Artiodactyla) from the early Oligocene, Fayum, Egypt, and the mystery of African ‘Rhagatherium’ solved

Authors:

Sileem et al

Abstract:

Recent work on new anthracothere (Mammalia, Artiodactyla) specimens from the Jebel Qatrani Formation, early Oligocene, Fayum, Egypt, has revealed the presence of a new genus. Nabotherium new genus is described on the basis of a partial skull, several mandibular and maxillary specimens, and isolated teeth. The new genus exhibits a distinctive combination of features not seen in other Paleogene anthracotheres. The most noticeable characteristics of the new genus include the presence of large and well-developed upper and lower canines, caniniform third incisors, the presence of only a short diastema between the canine and first premolar, and broad, bunodont cheek teeth. This is in contrast to other contemporary anthracotheres, including other forms from the Fayum, which show a spatulate third incisor, a reduced canine, a much longer canine-premolar diastema, and more narrow, bunoselenodont cheek teeth. The presence of a relatively short rostrum with closely packed incisors, low-crowned and simple premolars, and low-crowned, bunodont molars indicates that members of the new genus would have been more efficient at crushing foods than slicing vegetation, and suggests a more varied herbivorous and frugivorous diet than was favored by other, more bunoselenodont Fayum anthracotheres.

Jaggermeryx naida: a new Miocene Neogene Anthracothere From Egypt

Anthracotheres from Wadi Moghra, early Miocene, Egypt

Authors:

Miller et al

Abstract:

The early Miocene site of Wadi Moghra, Qattara Depression, Egypt, is important for interpreting anthracothere (Mammalia, Artiodactyla) evolution, because the Moghra sediments preserve a higher diversity of anthracotheres than any other pene-contemporaneous site. New specimens from Moghra are described and form the basis for the systematic revision of Moghra anthracotheres provided here. Among the important discoveries recently made at Moghra is the first complete skull of Sivameryx moneyi. Other new specimens described here include two new species of Afromeryx, and a new genus and species, all of which are unique to Moghra. A review of biogeographic information supports the conclusion that three of the Moghra anthracotheres (Brachyodus depereti, B. mogharensis, and Jaggermeryx naida, n. gen. n. sp.) are members of late surviving lineages with a long history in Africa, while three other species (Afromeryx grex, n. sp., A. palustris, n. sp., and Sivameryx moneyi) represent more recent immigrants from Eurasia.

Two New Miocene Crocodilian and Hippolike Anthracothere Found in Panama

University of Florida paleontologists have discovered remarkably well-preserved fossils of two crocodilians and a mammal previously unknown to science during recent Panama Canal excavations that began in 2009.

The two new ancient extinct alligator-like animals and an extinct hippo-like species inhabited Central America during the Miocene about 20 million years ago. The research expands the range of ancient animals in the subtropics — some of the most diverse areas today about which little is known historically because lush vegetation prevents paleontological excavations — and may be used to better understand how climate change affects species dispersal today. The two studies appear online today in the same issue of the Journal of Vertebrate Paleontology.

The fossils shed new light on scientists' understanding of species distribution because they represent a time before the formation of the Isthmus of Panama, when the continents of North and South America were separated by oceanic waters.

"In part we are trying to understand how ecosystems have responded to animals moving long distances and across geographic barriers in the past," said study co-author Jonathan Bloch, associate curator of vertebrate paleontology at the Florida Museum of Natural History on the UF campus. "It's a testing ground for things like invasive species – if you have things that migrated from one place into another in the past, then potentially you have the ability to look at what impact a new species might have on an ecosystem in the future."

The research was funded by the National Science Foundation Panama Canal Partnerships in International Research and Education project, which supports paleontological excavation of the canal during construction expected to continue through 2014.

"We're very fortunate we could get the funding for PIRE to take advantage of this opportunity — we're getting to sample these areas that are completely unsampled," said Alex Hastings, lead author of the crocodilian study and a visiting instructor at Georgia Southern University who conducted the research for the project as a UF graduate student.

Researchers analyzed all known crocodilian fossils from the Panama Canal, including the oldest records of Central American caimans, which are cousins of alligators. The more primitive species, named Culebrasuchus mesoamericanus, may represent an evolutionary transition between caimans and alligators, Hastings said.

"You mix an alligator and one of the more primitive caimans and you end up with this caiman that has a much flatter snout, making it more like an alligator," Hastings said. "Before this, there were no fossil crocodilian skulls known from Central America."

Christopher Brochu, an assistant professor of vertebrate paleontology in the department of geoscience at the University of Iowa, said "the caiman fossil record is tantalizing," and the new data shows there is still a long way to go before researchers understand the group.

"The fossils that are in this paper are from a later time period, but some of them appear to be earlier-branching groups, which could be very important," said Brochu, who was not involved with the study. "The problem is, because we know so little about early caiman history, it's very difficult to tell where these later forms actually go on the family tree."

The new mammal species researchers described is an anthracothere, Arretotherium meridionale, an even-toed hooved mammal previously thought to be related to living hippos and intensively studied on the basis of its hypothetical relationship with whales. About the size of a cow, the mammal would have lived in a semi-aquatic environment in Central America, said lead author and UF graduate student Aldo Rincon.

"With the evolution of new terrestrial corridors like this peninsula connecting North America with Central America, this is one of the most amazing examples of the different kind of paths land animals can take," Rincon said. "Somehow this anthracothere is similar to anthracotheres from other continents like northern Africa and northeastern Asia."

Researchers also name a second crocodilian species, Centenariosuchus gilmorei, after Charles Gilmore, who first reported evidence of crocodilian fossils collected during construction of the canal 100 years ago. The genus is named in honor of the canal's centennial in 2014.