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Rugosuchus (meaning "uneven or wrinkled crocodile", in reference to texturing on its upper jaw bones) is an extinct genus of neosuchian crocodyliform[1] from the late Early Cretaceous of China. It is known from most of a skull, a partial postcranial skeleton, and a second partial skeleton including part of the hips. It was described by Xiao-Chun Wu and colleagues in 2001, with R. nonganensis as the type species. At the time of its description, it was the most complete crocodyliform from northeastern China, and only the second known.
Rugosuchus is based on IGV 33, most of a skull. Wu et al. assigned two other specimens to this genus: IGV 31, much of a skeleton lacking a skull and most of the limbs; and IGV 32, three vertebrae, a partial hip, and a fragment of thigh bone. These three specimens had been collected in 1958 by the Petroleum Geological Survey of the Song-Liao Basin, and remained unstudied for many years. The locality is near Fulongquan, Nong'an County, Jilin, in the Song-Liao Basin. The formation is not known for certain, but is probably the Nenjiang Formation. The age of the Nenjiang Formation has been debated, but as of the description of Rugosuchus was thought to be latest Early Cretaceous, based on ostracode, bivalve, and fish fossils.[2]
Skull IGV 33 is thought to have come from an adult, based on the fusion of bones. It is somewhat elongate, being about 28 centimeters (11 in) long but only an estimated 13 centimeters (5 in) at its widest. The maxillae, the main tooth-bearing bones of the upper jaw, had unusual elongate depressions on their sides, nine or ten per maxilla. Other skull bones had heavily textured surfaces, as is seen on other crocodyliforms. The premaxillae at the tip of the snout had five teeth each, and the maxillae 16 or 17, with wide spacing; because the jaws are closed, the teeth of the lower jaw cannot be observed.[2]
Wu et al. noted that their new genus was not an eusuchian because of the form of the palatal bones, but it was probably more closely related to the eusuchians than other extinct crocodyliforms like Goniopholis by having more than two rows of bony armor running its length, and by the form of the armor. They interpreted Rugosuchus as similar to Bernissartia, Shamosuchus and the unnamed "Glen Rose Form", but not as derived.[2] However, a more recent phylogenetic analysis by Turner and Buckley (2008) places it with the "Glen Rose Form" in a clade with Eusuchia, more derived than Bernissartia.[3]
Rugosuchus (meaning "uneven or wrinkled crocodile", in reference to texturing on its upper jaw bones) is an extinct genus of neosuchian crocodyliform from the late Early Cretaceous of China. It is known from most of a skull, a partial postcranial skeleton, and a second partial skeleton including part of the hips. It was described by Xiao-Chun Wu and colleagues in 2001, with R. nonganensis as the type species. At the time of its description, it was the most complete crocodyliform from northeastern China, and only the second known.
皺褶鱷（學名：Rugosuchus）是種已滅絕中真鱷類，屬於新鱷類，生存於白堊紀早期的中國。化石包含：一個大部分頭骨、一個大部份的骨骼、另一副則包含部份骨盆與脊椎。皺摺鱷是由吳肖春等人在2001年命名，模式種是農安皺摺鱷（R. nonganensis）；屬名意為「有縐紋的鱷魚」，意指其表面不平的上頜骨。皺摺鱷被命名時，是當時中國東北部最完整的鱷形類化石，也是當地第二個發現的鱷形類。
皺摺鱷的模式標本（編號IGV 33）是一個大部分頭骨。吳肖春等人將兩個其他標本歸類於此屬。編號IGV 31標本，包含大部分骨骼，只缺少頭骨與大部分四肢；編號IGV 32標本，包含三節脊椎、部分骨盆、股骨碎片。在1958年，一次針對松遼平原的石油地質調查發現這些化石，但許多年來未曾研究過。發現地點位於中國吉林省農安縣伏龍泉鎮，化石所處的地層仍未確定，可能屬於嫩江組。嫩江組的年代仍在爭議中，但根據當地的介形綱、雙殼綱、與魚類化石，皺摺鱷的年代屬於白堊紀早期。[1]
根據骨頭的瘉合狀態，皺摺鱷的模式標本是個成年個體。這個頭骨的長度為28公分，寬度為13公分。上頜骨的側邊有獨特、延長的凹處，位在第9或10顆牙齒處。如同其他鱷形類，皺摺鱷的其他頭骨表面也是凹突不平。每塊前上頜骨有5顆牙齒，每塊上頜骨有16或17顆牙齒，牙齒間的間隔寬。[1]
吳肖春等人根據齶骨，認為皺摺鱷不屬於真鱷類；但從多於兩排的皮內成骨鱗甲，以及鱗甲的形狀，可知牠們比稜角鱗鱷等鱷形類，更接近真鱷類。他們認為皺摺鱷類似伯尼斯鱷、沙漠鱷、以及一種發現於玫瑰谷地區的未命名鱷形類，但沒有上述物種衍化。[1]在2008年的一份親緣分支分類法研究，皺摺鱷與未命名的玫瑰谷鱷形類被分類於真鱷類，比伯尼斯鱷衍化。[2]
|title=值左起第39位存在換行符 (帮助) 