Anancus
Anancus is an extinct genus of "tetralophodont gomphothere" native to Afro-Eurasia, that lived from the Tortonian stage of the late Miocene until its extinction during the Early Pleistocene, roughly from 8.5–2 million years ago.
Taxonomy
The type species, Anancus arvernensis, was originally named in 1828 by Jean-Baptiste Croizet and Antoine Claude Gabriel Jobert as Mastodon arvernensis, based on remains found within the vicinity of the Puy de Dôme volcano in the Massif Central in central southern France, with the species name deriving from the Auvergne region of France where it was found. Anancus was subsequently named by Auguste Aymard in 1855 in a publication by M. J. Dorlhac, also based on remains found in the Massif Central region. The genus name Anancus derives from the Latin word ancus meaning "bent/curved" and the negative prefix "an-" with the intended meaning of "uncurved, straight" in reference to the shape of the tusks. Anancus is traditionally allocated to Gomphotheriidae, often as the only member of the subfamily Anancinae. Recently, some authors have excluded Anancus along with other tetralophodont gomphotheres from Gomphotheriidae, and regarded them as members of Elephantoidea instead.Description
Two largely complete individuals of Anancus arvernensis reached shoulder heights of around, with a volumetric estimate suggesting a body mass of around, comparable to living African bush elephants. The tusks were largely straight and lacked enamel and were slender, and proportionally large, with a large tusk of the species Anancus avernensis from Stoina, Romania measuring in length with an estimated mass of. The tusks varied from projecting forward parallel to each other, to being outwardly divergent from each other, depending on the species. The skull is proportionally tall and short, with an elevated dome and an enlarged tympanic bulla. Unlike more primitive gomphotheres, the mandible was brevirostrine, and lacked lower tusks. The skull of Anancus species is very similar to living elephants and like them they probably had free-hanging trunks. The molars were typically tetralophodont but were pentalophodont in some species. The premolars were absent in all species other than A. kenyensis. On the upper molars, the posterior pretrite central conules were reduced, as were the anterior pretrite central conules on the lower molars. The pretrite and posttrite half-lophs were dislocated from each other, resulting in the successive lophs exhibiting an alternating pattern.Diet and ecology
Dietary preferences of Anancus varied between species. Dental microwear analysis of Anancus arvernensis specimens from the Early Pleistocene of Europe generally suggests that it was a browser, consuming twigs, bark, seeds and fruit, with a browsing diet also proposed for the Early Pliocene South African A. ''capensis. The East African late Miocene-early Pliocene A. kenyensis and Pliocene A. ultimus have individuals with varying browsing, grazing, and mixed feeding diets, with a grazing diet proposed for Anancus specimens from the Pliocene of India based on isotopic analysis. Anancus osiris from the Pliocene of North Africa is suggested to have been a mixed feeder with a large grass intake based on microwear.Anancus often coexisted alongside other proboscideans, such as the larger mastodon "Mammut" borsoni in Pliocene Europe. During the Pliocene-Early Pleistocene, Anancus coexisted with elephantids, including mammoths, and Loxodonta cookei who Anancus'' is suggested to have engaged in habitat and diet-based niche partitioning with.