Ctenochasma

Ctenochasma Temporal range: Late Jurassic - Early Cretaceous, 150–145 Ma PreЄ Є O S D C P T J K Pg N ↓
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Fossil specimen of a juvenile C. elegans
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Order:	†Pterosauria
Suborder:	†Pterodactyloidea
Family:	†Ctenochasmatidae
Subfamily:	†Ctenochasmatinae
Genus:	†Ctenochasma Meyer, 1852
Type species
†Ctenochasma roemeri Meyer, 1852
Species
†C. roemeri Meyer, 1852 †C. elegans (Wagner, 1861) [originally Pterodactylus] †C. taqueti Bennett, 2007
Synonyms
Ptenodracon Lydekker, 1888

Ctenochasma (meaning 'comb jaw') is a genus of Late Jurassic pterosaur belonging to the suborder Pterodactyloidea. Three species are currently recognized: C. roemeri (named after Friedrich Adolph Roemer), C. taqueti, and C. elegans. Their fossilized remains have been found in the Solnhofen Limestone of Bavaria, Germany, the "Purbeck Group" of northeastern Germany, and the Calcaires tâchetés of eastern France.

Description

File:Ctenochasma elegans 1.JPG

Fossil skull of a subadult C. elegans

Ctenochasma is distinguished mainly by its numerous (over 400 in adults) long, thin, curved and closely packed teeth, which lined its elongated and narrow snout. The teeth were so closely packed that they formed a comb, and in adults they projected outward away from the jaws, forming a basket, which was probably used in a filter feeding lifestyle, straining water through the teeth in order to capture and eat small invertebrates. The snout curved slightly upward and was rounded at the tip, and the teeth were restricted to the front half of the jaws.

The smallest species, Ctenochasma elegans, had a wingspan of only about 25 cm. Ctenochasma is distinguished by its mouth which contained as many as 260 long, thin comb-like teeth. Adult Ctenochasma had a bony crest along the skull, though this is not found in juveniles.

Comparisons between the scleral rings of both Ctenochasma elegans and Ctenochasma taqueti and modern birds and reptiles suggest that these taxa may have been nocturnal, and may have had activity patterns similar to modern nocturnal seabirds. This may also indicate niche partitioning with contemporary pterosaurs inferred to be diurnal, such as Pterodactylus and Scaphognathus.

Species

File:Pterodactylus elegans, Eichstatt, Germany, Late Jurassic - Royal Ontario Museum - DSC00047.JPG

Fossil specimen of a young juvenile C. elegans

The name Ctenochasma was coined by the German paleontologist Christian Erich Hermann von Meyer in 1852, based on a single lower jaw full of closely packed teeth which he gave the species name Ctenochasma roemeri. A second species, C. gracile, was named by Oppel in 1862 based on a fragmentary skull. However, a year earlier, another, more complete specimen probably belonging to the same species was described and named Pterodactylus elegans by Wagner. Because the species name elegans was named before gracile, the species is now known as Ctenochasma elegans. Another specimen originally attributed to a small or juvenile Pterodactylus, P. brevirostris (the second pterosaur to be named, which was later placed in its own genus Ptenodracon), probably represents a young juvenile Ctenochasma. An additional species, C. porocristata, was named by Paul de Buisonjé in 1981. However, it was differentiated mainly by the presence of a crest along the snout, which has since been shown to be a feature related to growth or sex, rather than species.

A fourth species of Ctenochasma was first described (but not named) by Philippe Taquet in 1972. A single specimen, consisting of a partial skull with complete brain case, was found in France and housed in the collections of the Saint-Dizier Museum. Detailed comparison to other Ctenochasma specimens in 2004 confirmed that it was a new species. In honor of Taquet's work on the specimen, Christopher Bennett named the species C. taqueti in 2007.

Classification

File:Gnathosaurus macrurus 1.jpg

Fossil specimen of a young juvenile C. elegans

File:Ctenochasma.jpg

Skeletal restoration

Cladogram following Andres, Clark & Xu, 2014.

Ctenochasmatidae	Gnathosaurinae  Kepodactylus insperatus Elanodactylus prolatus Feilongus youngi Moganopterus zhuiana Huanhepterus quingyangensis Plataleorhynchus streptophorodon Gnathosaurus subulatus Gnathosaurus macrurus  Ctenochasmatinae  Ctenochasma Pterodaustro guinazui Eosipterus yangi Beipiaopterus chenianus Gegepterus changi

See also

• List of pterosaurs

• von Meyer, C.E.H. (1852). "Ctenochasma Roemeri." Paläontographica, 2: 82–84 & pl. 13.
• Oppel A. (1862). "Über Fährten im lithographischen Schiefer. Paläontologische Mitteilungen aus dem Museum des Koenigl." Bayrischen Staates, ed. A. Oppel, vol. 1, pp. 121–125 & pl. 39. Stuttgart: Ebner & Sembek.