Parapsicephalus

Parapsicephalus Temporal range: Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Fossil skull showing brain endocast ( AMNH 1694)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Order:	†Pterosauria
Family:	†Rhamphorhynchidae
Genus:	†Parapsicephalus Arthaber, 1919
Type species
†Scaphognathus purdoni Newton, 1888
Species
†P. purdoni (Newton, 1888)
Synonyms
Scaphognathus purdoni Newton, 1888 Dorygnathus purdoni (Newton, 1888)

Parapsicephalus (meaning "beside arch head") is a

The type skull of Parapsicephalus, which is 14 centimetres (5.5 in) long as preserved, suggests that it was of medium size.[1] Comparisons with the related pterosaurs Scaphognathus, Dorygnathus, and Jianchangnathus indicates that the full skull would have been 18–19.6 centimetres (7.1–7.7 in) long.^[1][2][3] Wellnhofer estimated its wingspan at 1 metre (3 ft 3 in);^[4] more recently, a referred humerus, which is 10 centimetres (3.9 in) long, has produced wingspan estimates of 1.68–3.26 metres (5 ft 6 in – 10 ft 8 in).^[5]

Skull

When viewed from the side, the convex top of the skull formed a gentle slope. The elongate frontal process of the premaxilla, which extends backwards towards the eyes, may have supported a low crest along its midline.^[6] Below the nostril, the premaxilla meets with the maxilla; their junction is marked by a discontinuity in the surface texture of the bone. Overall, the oval-shaped antorbital fenestra, situated behind and separate from the nostril, measures 45 millimetres (1.8 in) long and 24 millimetres (0.94 in) tall. The maxilla extends backwards in a half-moon shape to encircle the front end of the fenestra, with the top prong of the maxilla forming a 45° angle with the horizontal. The top end of the fenestra is enclosed by the thin, rectangular, and slightly concave nasal, and the lacrimal, which is not well-preserved but may have been long, slender, and triangular. On the underside of the skull, the maxilla forms the majority of the palate (not the premaxilla, as previously assumed^[7]), extending back from below the external nostrils. Along the midline of the maxilla is situated a thin strip of bone, the vomer, which connects back to join the pterygoid.^[1]

At the back of the antorbital fenestra is the

GSM 3166 was described by Edwin Tulley Newton, who loaned it from Rev. Purdon, in 1888. He described it as a species of Scaphognathus, S. purdoni, named after Purdon; he did not include it in the type species S. crassirostris due to differences in the curvature of the top of the skull, as well as the midline channel on the top of the skull. In his description of the braincase, he noted its intermediate morphology between that of lizards and birds, which he considered evidence of a close relationship between birds, pterosaurs, and "reptiles".^[7] F. Plieninger subsequently compared GSM 3166 to Campylognathoides, and expressed that it was not as close to Scaphognathus as Newton had presumed.^[12] Later, in 1919, Gustav von Arthaber, based on the shape of the top of the skull, the elongated nostrils and prefrontal bones, the large antorbital fenestra and eye socket, the deep jugal, and the presence of seven teeth in the maxilla, referred GSM 3166 to the new genus Parapsicephalus.^[1][13]

Possible synonymy with Dorygnathus

In 2003,

The specimen NHMUK PV R36634 was found in 2011 within a concretion in Saltwick Bay, which also belongs to the Alum Shale Member.^[1] It consists of a scapula, coracoid, and humerus; the head of the humerus was broken off during excavation as a result of the concretion being hammered open (which is the usual method for exposing ammonites preserved in concretions). Although it is impossible to refer this specimen to Parapsicephalus with confidence, its provenance and similarity to Dorygnathus were the basis of the tentative identification of the specimen as belonging to this genus.^[5] An additional possible specimen is a skull collected in 1994 from Altdorf, Bavaria, Germany, which bears great similarity to GSM 3166 and also preserves some additional elements. It is currently held by a private collector, but will soon be donated to an institution in the UK.^[1]

Classification

Although Newton originally considered Parapsicephalus as being a species of

Pterosauria	Preondactylus buffarinii Austriadactylus cristatus Peteinosaurus zambellii Eudimorphodontidae Macronychoptera Dimorphodon macronyx Parapsicephalus purdoni Novialoidea

A 2017 analysis of Parapsicephalus found little support for it being placed in the Dimorphodontia: its skull was comparatively longer; the snout is slightly upturned with outward-projecting teeth, as in rhamphorhynchids; the quadrate is not as vertical; the antorbital fenestra is offset below the nostril instead of being at the same level; and, although the top of the skull is convex in both, the condition in Parapsicephalus is not quite as extreme. Thus, affinities with the Rhamphorhynchidae were considered more probable. Within the Rhamphorhynchidae, unlike the scaphognathines, the antorbital fenestra is more than twice as long as it is tall,^[8][14] and has a concave back margin; the angle of the quadrate is also more than 120°.^[23] This implies that Parapsicephalus is a member of the Rhamphorhynchinae.^[1]

However, there are some factors that complicate a rhamphorhynchine position. In particular, the pear-shaped

infratemporal fenestra and the overall size of the antorbital fenestra are more similar to scaphognathines than rhamphorhynchines. Additionally, like more basal non-rhamphorhynchid pterosaurs, there is a half moon-shaped process of the premaxilla extending beneath the nostril. It is thus possible that Parapsicephalus represents a basal rhamphorhynchid that is not in either group, which is not unexpected given its temporal context. The contemporary Allkaruen^[24] is also a potentially viable subject of comparison, although its material and that of Parapsicephalus do not readily overlap.^[1]

Paleoecology

The Alum Shale Member of the

ichthyosaurs Stenopterygius, Temnodontosaurus, and Eurhinosaurus; the plesiosaurs Eretmosaurus, Sthenarosaurus, and Microcleidus; and the thalattosuchians Steneosaurus and Pelagosaurus. Indeterminate theropod remains have also been found.^[1][9]

See also

• List of pterosaur genera
• Timeline of pterosaur research

References

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