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Antlerpeton
''Antlerpeton'' is an extinct genus of early tetrapod from the Early Carboniferous of Nevada. It is known from a single poorly preserved skeleton from the Diamond Peak Formation of Eureka County. A mix of features in its compound vertebrae suggest that ''Antlerpeton'' is a primitive stem tetrapod that has affinities with later, more advanced forms. Its robust pelvis and hind limbs allowed for effective locomotion on land, but the animal was likely still tied to a semiaquatic lifestyle near the coast.
== Description and history ==
The holotype skeleton of ''Antlerpeton'', ANS VP 19909, is the only known specimen of the genus. It was found in a block of mudstone in the form of fragmentary bones and natural molds. A latex impression was made to study ANS VP 19909 in greater detail. No other plant or animal fossils were found in the surrounding area. ''Antlerpeton'' was first described by Keith Stewart Thomson, Neil Shubin, and Forrest Poole in 1998. It was named after the Antler highlands, a group of mountains in Nevada and Utah that formed during the Late Devonian and Early Carboniferous. The type species ''A. clarkii'' was named for Charles W. Clark, a geologist of the Western Mining Corporation (an Australian mining company with an exploration office in Reno, Nevada) who discovered the holotype in 1990.〔
The holotype of ''Antlerpeton'' consists of vertebrae, ribs, a pelvic girdle, two broken femora, and gastralia. All of the bones are articulated. With up to 28 vertebrae, the presacral vertebral column (the part of the column in front of the pelvic girdle) is long. Each vertebral segment is composed of a large principal centrum and a pair of two small bones that fit in front of it. The spinal cord passes through the larger bones, while the smaller bones are positioned to either side of the midline. Pubo-ischiadic plates, primitive forms of the pubis and ischium of later tetrapods, are present, but it is unclear whether they were fused into a strong pelvic girdle. A small projection of bone is present on the acetabulum, a depression in the pelvis that attaches with the end of the femur. This projection is also seen in the Late Devonian tetrapod ''Ichthyostega''. The femur of ''Antlerpeton'' is much more robust than that of ''Ichthyostega'', and has prominent ridges like the fourth trochanter that are attachment points for well-developed leg muscles. ''Antlerpeton'' also has small scales covering its underside.〔
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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