Anancus

Skeletal reconstruction in the Palaeontological Museum of Florence (Museo di Firenze Paleontologico ).

• Africa
• Europe
• Asia

Anancus (from Greek: an- = un and Latin: Ancus = curved) is an extinct genus of Proboscidea and form part of the large group of mastodons. Within those he represents a late representative and emerged from the gomphotheres. A distinction is made about ten species. Anancus part with partly more than 3.5 meters shoulder height of the largest species of mammoths and lived about 7-2 million years ago.

Features

Anancus was a big tusker and had compared to the gomphotheres already much more advanced features in the direction of the Real elephants ( Elephantidae ). So he had a short skull with a convex-shaped and significantly higher than in his skull roof phylogenetically older relatives. The alveoli of the maxilla were to each other in a distinct angle, the embedded tusks reaching up to 3 m in length. The mandible was significantly reduced, which led to the fact that typical of the gomphotheres mandibular tusks were strongly stunted or completely missing.

The dentition was characterized by three bunodonte molars in each pine bough. The two front molars each had four strips with high enamel protuberances at the ends, while the last molars having five or six strips. There was a marked in the teeth of Anancus that these bars do not consistently ran but was divided ( half-yokes ) and were alternately offset from one another. The two last - - premolars formed in the primary dentition were still.

The tusks were almost completely just what the genus Proboscidea its name, and in the larger representatives of up to 3 m long. Your broad- round cross-section, they differed from the tusks of gomphotheres which had often horizontal or vertical compressions. A 2004 in the Siwaliks (Pakistan ) found specimen had a length of 2.72 m with a maximum diameter of 17.2 cm. Noteworthy are occurring in the cross-section Schreger lines, rosette-like shaped, alternating light and dark colored structures that go back to a regular change of the collagen content in the dentin. These structures are also other animals snout with large tusks, like today's elephants, mammoths, but also in some mastodons, available. The angles at which the lines meet regularly, are very sharp at Anancus and thus differ from those of other characteristic proboscis species.

Distribution and species

The distribution area of Anancus included large parts of the Old World. The tusker was common throughout Eurasia and penetrated to the north before to England, in the East it was found on the Japanese islands. Quite often it occurred also in Central Asia. Furthermore Anancus is also detected in North and Central Africa, but for the last region he disappeared relatively early. In Central Europe finds of Anancus are relatively rare. Proved they are in sediments from the upper Miocene and Pliocene of Rheinhessen and Hesse. Significant Fund areas are especially the buckthorn Durkheim lineup and the so-called arvernensis - gravel of the Mainz Basin.

So far, ten species have been described from Anancus. Their taxonomic independence is not assured in any case, because it is partly of some paleontologists, according also to synonyms. So Anancus osiris is kenyensis as a synonym of Anancus or Anancus alexeevae viewed as such by Anancus arvernensis.

• Anancus alexeevae, Upper Pliocene, Europe;
• Anancus arvernensis ( Croizet and Jobert 1828), type species, Pliocene to lower Pleistocene, Europe;
• Anancus capensis ( Sanders 2007);
• Anancus kazachstanensis ( Auberkova 1974), Upper Pliocene, Central Asia;
• Anancus kenyensis ( MacInnes 1942), late Miocene of Central and East Africa, the Pliocene of North Africa;
• Anancus osiris ( Arambourg 1945), Pliocene, North Africa;
• Anancus perimensis ( Falconer and Cautley 1847), South Asia ( Siwaliks, India);
• Anancus petrocchii ( Coppens 1965), Upper Miocene, North Africa;
• Anancus sinensis ( Hopwood 1935), Pliocene, East Asia;
• Anancus sivalensis ( Cautley 1837), Pliocene South Asia ( Siwaliks, Pakistan ).

Phylogeny

Anancus first appeared at the end of the Miocene about 7 million years ago and replaced Tetralophodon, from which it is derived probably. Both genera are closely related to the gomphotheres. Due to their striking design of the front molars with four horizontal bars are also referred to as " tetralophodonte " gomphotheres, while researchers assign the phylogenetically older real gomphotheres the " trilophodonten ". The bunodonte tooth structure suggests a specialized leaf -eaters (browser ). However, some of the later representatives, such as Anancus alexeevae also showed adaptations to open landscapes. In the lower Pleistocene some 1.8 million years ago Anancus disappeared. The extinction of this animal with a trunk genus is probably causally related to the climatic changes at the transition from Pliocene to Pleistocene together that favored the spread of open landscapes with training from steppes in many parts of Eurasia.

Taxonomy

Auguste Aymard, curator at the Musée Crozatier in Le Puy -en -Velay in France, made in the first half of the 19th century around the city again and again finds of teeth and bones of mastodons, including a nature which he later Anancus macro plus called it. A bone of the metacarpal and two molars were described in 1847 in the Bulletin de la Société Géologique de France, but without the mention of the name Anancus. Paleontology at that time was still in its early stages and so it came true for compiling a list of discovered by Auguste Aymard species at a meeting of the Société Academique in January 1855 as well as a mention in the writings of Congres Scientifique de France in 1855, but applicable to any first description of the genus Anancus or type Anancus macro plus. Together with other Early Pleistocene mammal remains from the Auvergne, the fossils of mastodons were kept in the Musée Croizet. 1859 compared Edouard Lartet the labeled Anancus macro plus teeth with those of Mastodon arvernensis, which had been described in 1828 by Jean -Baptiste Croizet and Antoine Claude Gabriel Jobert. Although Croizet and Jobert had just found baby teeth, put Lartet found that they had the same construction as that of Anancus macro plus. The previously discovered Mastodon arvernensis was therefore the type species of the genus Anancus and the name to Anancus arvernensis recombined. As the year of first description of Anancus is usually given in 1855, but many paleontologists are of the opinion that this species has only been described by the work of Lartet 1859 valid.

Originally saw Anancus as a genus within the gomphotheres the superfamily Gomphotherioidea. Based on recent studies, including from Jehezekel Shoshani and Pascal Tassy but was again separated from the group and, by reason of their more modern Schädelbaues to the base opposite the gomphotheres advanced superfamily Elephantoidea, which also includes the Stegodonten and today's elephants belong. An assignment to a particular family was carried out up to now not yet ( incertae sedis family ). But some paleontologists remain with the traditional outline and leave Anancus at the gomphotheres.