Glyphoderma: Difference between revisions

Revision as of 02:47, 9 January 2019

Revision as of 22:54, 4 February 2019

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{{Automatic taxobox

| taxon = Glyphoderma

| fossil_range = [[Middle Triassic]]

| authority = Zhao ''et al.'', [[2008 in paleontology|2008]]

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}}

'''''Glyphoderma''''' is an extinct [[genus]] of [[placodont]] reptile from the [[Middle Triassic]] of [[China]]. It differs from its relative ''[[Psephochelys]]'' in having three, rather than one, fused [[Osteoderm|osteodermsosteoderm]]s on the posterior [[skull]] surface, and has an earlier temporal range, from the [[Ladinian]] epoch rather than the [[Late Triassic]]. Otherwise, it is similar in most respects to the other [[Placochelyidae|plachochelyids]] found in China. The name comes from the [[Ancient Greek|Greek]] 'γλυφος', 'sculpture' and 'δερμα', 'skin' referring to its unique carapace structure. The specific name honours a Mr. Kang Ximin.<ref name=ZLLH08>{{cite journal |last=Zhao |first=L.-J. |author2=Li, C. |author3=Liu, J. |author4= He, T. |year=2008 |title=A new armored placodont from the Middle Triassic of Yunnan Province, Southwestern China |journal=Vertebrata PalAsiatica |volume=46 |issue=3 |pages=171–177 |url=http://www.ivpp.cas.cn/cbw/gjzdwxb/xbwzxz/200811/W020090813369302050276.pdf}}</ref>

The [[holotype]], an almost complete skeleton, was found in 2008 in Fuyuan, [[Yunnan Province, Republic of China|Yunnan Province]] of central China in the Falan Formation. It is preserved in a thick block of [[limestone]], and so the ventral side is not well known. The total length is 873 &nbsp;mm.<ref name="ZLLH08" />

== Features ==

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=== Vertebrae and tail ===

''Glyphoderma'' has five or six [[cervical vertebrae]], all of which are very flattened and wide, with low [[neural spines]]. Only one [[Thoracic vertebrae|dorsal vertebra]] can be seen beneath the carapace. There are four [[sacral vertebrae]], with distally expanded [[pleurapophyses]] enclosing a [[foramen]] between each pair. 34 [[Vertebra|caudal vertebrae]] are preserved, although some may be missing, and the first three of them have transverse processes. <ref name="ZLLH08" />

=== Front legs ===

Only the distal end of each [[scapula]] is exposed by the carapace, but the [[Humerus|humeri]] are well preserved and exposed, at 65.7 &nbsp;mm long. The distal end of each humerus is expanded, with a flat triangular depression on the dorsal side, and an open [[ectepicondylar groove]] along the anterior margin. The [[ulna]] and [[Radius (bone)|radius]] are of very similar lengths (39.5 and 40.8 &nbsp;mm respectively) but the radius is much thicker. Both ends of the radius have a depression on the dorsal surface. There are five [[Ossification|ossificationsossification]]s in the [[Carpal bones|carpus]], but the [[Hand|manus]] is very poorly preserved and we know almost nothing about it.<ref name="ZLLH08" />

=== Hind legs ===

The [[femur]] is expanded at both ends, but has a short shaft (only 59 &nbsp;mm). The space between the [[tibia]] and [[fibula]] is very large as the tibia has a straight medial edge and a concave lateral one. They are roughly the same length (47.5 &nbsp;mm fibula, 49.4 &nbsp;mm tibia). The [[Calcaneus|calcaneum]] and astragalus form a depression for the distal end of the tibia to fit into. There are four other [[Tarsus (skeleton)|tarsals]] and four [[Metatarsal bones|metatarsals]], but it is very difficult to determine the phalangeal formula due to the poor preservation of the foot.<ref name="ZLLH08" />

==References==

{{reflistReflist}}

{{Sauropterygia|P.}}

[[Category:Middle Triassic reptiles of Asia]]

[[Category:Placodontia]]

{{triassic-reptile-stub}}