Fossils of oldest elephant relative found
60-million-year-old remains show much smaller tusks than current animals’
June 22, 2009
Scientists have discovered fossilized remains of the oldest known elephant relative, dating back 60 million years.
The fossils were found in Morocco. Called Eritherium azzouzorum, the animal would not have looked much like an elephant. It was just 1.6 to 2 feet (50 to 60 cm) long and weighed 9 to 11 pounds (4 to 5 kg).
The animal’s relation to elephants was determined via analysis of the specimen’s teeth and skull. While it lacked a trunk, the animal had an enlarged first incisor, which researcher Emmanuel Gheerbrant of the National Museum of Natural History in Paris says represents a primitive tusk. It was much smaller than the tusks of today’s elephants.
“The trunk evolved with the modern elephant group, called elephantiform, at the beginning of the Oligocene,” which extends from 33.7 million to 23.8 million years ago, Gheerbrant told LiveScience.
The fossil mammal was found in the same area that yielded the then-oldest elephant relative called Phosphatherium escuilliei, which dated back 55 million years.
The research was published in the June 22 issue of the journal Proceedings of the National Academy of Sciences.
Jon Smith, a scientist at the Kansas Geological Survey, and Stephen Hasiotis, a geologist at the University of Kansas, have demonstrated that soil-inhabiting creatures contracted in size by 30-46 percent during the Palaeocene-Eocene Thermal Maximum (PETM). The PETM was a short interval 55 million years ago marked by a spike in the atmosphere’s carbon dioxide levels and global temperatures, conditions being repeated on Earth now: here.
Seventeen species from the Palaeocene and Early Eocene of northern Europe, of which 12 are new, are described belonging to the extinct macroscelidean family Louisinidae, raised here from subfamily rank. These species belong to nine genera, of which five are new. The new genera are Walbeckodon, Berrulestes, Gigarton, Thryptodon, and Prolouisina. The new species are Walbeckodon krumbiegeli, Walbeckodon girardi, Paschatherium levei, Berrulestes phelizoni, Berrulestes pellouini, Berrulestes poirieri, Gigarton meyeri, Gigarton sigogneauae, Gigarton louisi, Thryptodon brailloni, Louisina marci, and Teilhardimys brisswalteri. Prolouisina is erected for ‘Louisina’ atavella Russell, 1964. Cladistic analysis was undertaken to understand the relationships within the Louisinidae and between them and the North American family Apheliscidae, in which they had earlier been included as a subfamily. Louisinidae are shown to be sister group to a clade consisting of Apheliscidae plus Amphilemuridae and part of a paraphyletic and polyphyletic Adapisoricidae, all of which are tentatively considered to be stem members of the order Macroscelidea. The most primitive macroscelidid, Chambius, from the Early Eocene of northern Africa is nested within Apheliscidae when postcranial characters were included, but in a majority of cases within the Louisinidae when postcranial characters were excluded. Most species from northern Europe became extinct at the end of the Palaeocene, although the genus Paschatherium survived for much of the Early Eocene and Teilhardimys survived into the earliest Eocene: here.