| 翻訳と辞書 |
| Saurornithoides ： ウィキペディア英語版 |
Saurornithoides
''Saurornithoides'' ( ) is a genus of troodontid maniraptoran dinosaur, which lived during the Late Cretaceous period. These creatures were predators, which could run fast on their hind legs and had excellent sight and hearing. The name is derived from the Greek stems ''saur~'' (lizard), ''ornith~'' (bird) and ''eides'' (form), referring to its bird-like skull.
==Description==
''Saurornithoides'' is a member of the troodontids, a group of small, bird-like, gracile maniraptorans. All troodontids have many unique features of the skull, such as closely spaced teeth in the lower jaw, and large numbers of teeth. Troodontids have sickle-claws and raptorial hands, and some of the highest non-avian encephalization quotients, meaning they were behaviourally advanced and had keen senses. ''Saurornithoides'' was a rather small troodontid. Though a possible adult, the type specimen has a midline skull length of 189 millimetres, compared to 272 millimetres for ''Zanabazar junior'', itself estimated at 2.3 metres long. It had large eye sockets and stereoscopic vision, allowing for good depth perception. It probably had good vision in light and very good night vision. It had a long, low head, a depressed muzzle, sharp teeth and a relatively large brain. Swift and smart, like its North American cousin ''Troodon'', ''Saurornithoides'' probably scoured the Gobi Desert, looking for small mammals or reptiles to eat. Like other troodontids, it had an enlarged retractable claw on the second toe of each foot, that in this case was of moderate size though rather curved.〔
A revision of the genus in 2009 provided a differential diagnosis, a list of traits in which ''Saurornithoides'' differed from certain relevant relatives, especially concentrating on determining its place in the evolutionary tree. That ''Saurornithoides mongoliensis'' might be more derived, higher in the tree, than ''Sinornithoides'' and ''Sinusonasus'', is indicated by the lack of a ''fenestra promaxillaris'', a small opening at the front side of the snout, and the possession of large denticles on the rear tooth edges as well as the presence of the high number of six sacral vertebrae. That ''S. mongoliensis'' might be more basal, lower in the tree, than ''Zanabazar'' and ''Troodon'', is shown by the presence of a ''recessus tympanicus dorsalis'', the upper one of three small openings on the side of the braincase, in the inner ear region.〔
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「Saurornithoides」の詳細全文を読む
スポンサード リンク
| 翻訳と辞書 : 翻訳のためのインターネットリソース |
Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.
|
|