Douzhanopterus
Douzhanopterus | |
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Photograph of the type specimen of Douzhanopterus (a) with closeups of the tail (b) and foot (c) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Order: | †Pterosauria |
Clade: | † Pterodactyliformes
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Genus: | †Douzhanopterus Wang et al., 2017 |
Type species | |
†Douzhanopterus zhengi Wang et al., 2017
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Douzhanopterus is an extinct genus of
Discovery and naming
The
In 2017, the
Description
Douzhanopterus was a relatively small pterosaur, with a wingspan of only 74 centimetres (29 in). The only known specimen represents an adult, judging by the degree of fusion in the hand bones, scapulocoracoid, and the tibia-fibula, as well as the fusion of the extensor tendon on the wing to the first phalanx of the wing.[2][3][4]
Out of nine
Overall, the sternum is about as long as it is wide, with a forward-projecting front margin but a straight back margin. The scapula is slender and long, being about 40% longer than the coracoid; the coracoid itself does not bear any sort of expansion on its bottom surface. On the humerus, the deltopectoral crest is short and trapezoidal, and is placed at the top of the bone. A small crest is also present where the humerus articulates with the ulna. The pteroid, a bone unique to pterosaurs, is quite long, being about half as long as the ulna. In front of the pteroid, there is a small sesamoid bone that is attached to the outer edge of the carpals. The digits of the non-wing hand are somewhat long, being about 65% of humerus length and 53% of ulna length, and bear large claws. On the wing finger, the second phalanx is the longest, followed by the first and third, and then the fourth, which is still about 80% the length of the second.[2]
Fused entirely to the sacrum is the pelvic girdle. The portion of the pelvic girdle in front of the femoral joint appears to consist of two unfused prepubes, which are longer than they are wide. The femur is slightly curved, and the femoral head and neck form an angle of about 150° with the shaft. On the lower leg, the relatively straight tibia is about 180% the length of the femur; the fibula, which is about 45% the length of the tibia, is fused to it at both ends. Further below, the five metatarsals are rectangular. The second metatarsal is also the longest, followed again by the first and third, and then the fourth, with the third metatarsal being about 31% the length of the tibia. Unusually, the fifth digit of the foot still has two phalanges, the first straight and the second curved; the first is about 20% the length of the third metatarsal.[2]
Classification
In 2017, Wang et al. assigned Douzhanopterus to the Monofenestrata. Douzhanopterus exhibits a number of characteristics that are intermediate between more basal pterosaurs, including the Wukongopteridae,[6][7][8][9] and the more derived Pterodactyloidea. In particular, the cervical vertebrae are generally longer; the tail is less than half of body length but still not particularly reduced; the metacarpals are moderately long compared to the humerus and ulna; and the fifth digit of the foot still bears two phalanges, although they are reduced with respect to basal pterosaurs but still larger than pterodactyloids. Its position in the phylogenetic tree recovered by Wang et al., the topology of which is partially reproduced below, is consistent with its intermediate condition.[2]
Monofenestrata |
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More derived than Douzhanopterus is the "Painten pro-pterodactyloid", an unnamed juvenile specimen from the
References
- .
- ^ PMID 28202936.
- JSTOR 2400773.
- PMID 26131631.
- .
- PMID 19893903.
- PMID 19828548.
- PMID 21152776.
- .
- ^ a b Tischlinger, T.; Frey, E. (2013). "A new pterosaur with mosaic characters of basal and pterodactyloid pterosauria from the Upper Kimmeridgian of Painten (Upper Palatinate, Germany)". Archaeopteryx. 31: 1–13.