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''Prodeinotherium'' is an extinct representative of the family Deinotheriidae that lived in Africa, Europe, and Asia in the early and middle Miocene. ''Prodeinotherium'' was first named in 1930, meaning "before terrible beast", but soon after the only species in it, ''P. hungaricum'', was reassigned to ''Deinotherium''. During the 1970s however, the two genera were once again separated, with ''Prodeinotherium'' diagnosed to include ''Deinotherium bavaricum'' (=''P. hungaricum''), ''Deinotherium hobleyi'', and ''Deinotherium pentapotamiae'', which were separated based on geographic location. The three species are from Europe, Africa, and Asia respectively. However, because of usage of few characters to separate them, there may have been only one species, ''P. bavaricum'', or many more species, including ''P. cuvieri'', ''P. orlovii'', and ''P. sinense''. ''Prodeinotherium'' is one of three genera of Deinotheriidae, the others being ''Chilgatherium'' from Africa, and ''Deinotherium'' from Europe, Africa and Asia. ''Chilgatherium'' preceded ''Prodeinotherium'', while ''Deinotherium'' succeeded it. ''P. hobleyi'' was the first species of ''Prodeinotherium'', and it migrated into Asia and Europe before evolving into ''P. pentapotamiae'' and then ''P. bavaricum''. ''Prodeinotherium'' lived for the Early Miocene and Middle Miocene before being replaced by ''Deinotherium''. The deinotheriids are an early branch of proboscideans, although more derived than ''Barytherium'' and ''Moeritherium''. All deinotheres were large animals that evolved to be even larger, and many features are shared throughout the group. ''Prodeinotherium'' and ''Deinotherium'' both had large downcurved tusks on the lower jaw, but none on the upper jaw. They may have had a tapir-like snout, muscular but not as long as an elephant's trunk. This could have been used to grasp food while the tusks moved branches out of the way. ''Prodeinotherium'' was slightly smaller than ''Deinotherium'', yet much larger than more primitive proboscideans. All ''Prodeinotherium'' species were similar in size, ranging from tall and weighing about . ==Description== ''Prodeinotherium'' was the size of the present Asian elephant, about at the shoulders, but differing from elephants by lacking upper tusks and instead possessing downward-facing lower tusks.〔 In appearance and many characters it was like ''Deinotherium'', but differed in being of smaller size, having shorter forelimbs, and also in various details in the shape and form of the teeth.〔Sanders, W. J., Kappelman, J. & Rasmussen, D. T., 2004 ( New large-bodied mammals from the late Oligocene site of Chilga, Ethiopia. ''Acta Palaeontologica Polonica'' ) Vol. 49, no.3, pp. 365–392〕 An potentially adult female specimen of ''P. bavaricum'' is estimated to be tall and weight , while an adult male measured tall and was about . The earliest species ''P. hobleyi'' was estimated at similar tall and . ''Prodeinotherium hobleyi'' was larger and more specialised than its Oligocene predecessor ''Chilgatherium''. It flourished for several millions of years, before being replaced in the middle Miocene by the much larger ''Deinotherium''.〔 ''Prodeinotherium'' is distinguished from ''Deinotherium'' from multiple features, including: possessing a different dental formula of 003/103 and 0023/1023; M2-3 with an ornamentation; the rostrum turns down parallel to the mandibular symphysis; the rostrum and external nares narrow; the swelling of the preorbital is close to the orbit; the roof of the skull is longer and wider than in ''Deinotherium''; the articulation between the neck vertebrae and skull is more upturned; the skeleton is graviportally adapted; the scapula has a prominent spine and a stout acromion and metacromion; and the carpal bones and tarsal bones are narrow, but not dolichopodous. Deinotheres like ''Prodeinotherium'' have a muscle attachment for a trunk-like structure. However, a study in 2001 found that instead of an elephant-like trunk the appendage was more muscular and similar to a tapirs snout. They also found that within the evolution of ''Prodeinotherium'', the pair "tongs" at the end of the trunk were lost.〔 ''P. bavaricum'' is the most well-studied species of ''Prodeinotherium'', with multiple features shared among all specimens, not necessarily to the exclusion of other species. Some of these features include "small size, generally simple dental structure, less enamel plication and crenulation and thus the valleys of the premolars are well separated, slender teeth, bicuspid mesial lophid in P3 (the cuspids are distinct but more compressed against each other than in P. hobleyi), and clear mesial projection (“preprotolophide”) in P3; sometimes is bicuspid." Other features noted earlier in 1957 include "the mesial lophid of P3 is well separated into two cuspids, the mesial projection of P3 is well developed and often bicuspid, and the base of the protoconid in P3 is longer than that of the metaconid." ''P. hobleyi'' differs in morphology from ''P. bavaricum'' mostly in these P3 characteristics.〔 All deinothere mandibles have the same basic anatomy, with a downturned symphysis, and lower incisors. Most differences of deinothere genera are in the P3 tooth morphology and dimensions of the mandible and teeth. Measurements of the mandible have shown that the curve of the jaw is relative to the length of the jaw, a longer jaw and a stronger curve. A distinguishing feature of ''Prodeinotherium'' is that the area at the base of the curve in the jaw is flat, while there is a depression in all specimens of ''Deinotherium''. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Prodeinotherium」の詳細全文を読む スポンサード リンク
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