 |
| Nurhachius luei
Zhou, Pêgas, Leal & Bonde, 2019
DOI: 10.7717/peerj.7688
|
Abstract
A new istiodactylid pterosaur, Nurhachius luei sp. nov., is here reported based on a complete skull with mandible and some cervical vertebrae from the lower part of the Jiufotang Formation of western Liaoning (China). This is the second species of Nurhachius, the type-species being N. ignaciobritoi from the upper part of the Jiufotang Formation. A revised diagnosis of the genus Nurhachius is provided, being this taxon characterized by the presence of a slight dorsal deflection of the palatal anterior tip, which is homoplastic with the Anhangueria and Cimoliopterus. N. luei sp. nov. shows an unusual pattern of tooth replacement, with respect to other pterodactyloid species. The relationships within the Istiodactylidae and with their closest taxa are investigated through a phylogenetic analysis by parsimony.
 |
| Figure 1: Nurhachius luei sp. nov., BPMC-0204, holotype, photograph, and line drawing. The scale bar in the line drawing equals 50 mm.
Abbreviations: alv, alveolus; an, angular; art, articular; ax, axis; ceI, ceratobranchial I; ch, choana; cv, cervical vertebra; d, dentary; f, frontal; j, jugal; la, lacrimal; m, maxilla; n, nasal; naof, nasoantorbital fenestra; odp, odontoid process; or, orbit; pa, parietal; pf, prefrontal; pmax, premaxilla; po, postorbital; prid, palatal ridge; pty, pterygoid; q, quadrate; vo, vomer. Isolated numbers indicate tooth positions. Note: the visible region of the pterygoid corresponds to the medial process of the bone. Photo by Xuanyu Zhou. Drawing by Maria Eduarda Leal.
|
Systematic Paleontology:
Pterosauria Kaup, 1834
Pterodactyloidea Plieninger, 1901
Istiodactylidae Howse, Milner & Martill, 2001 (sensu Andres, Clark & Xu, 2014)
Nurhachius Wang et al., 2005
Type species. Nurhachius ignaciobritoi Wang et al., 2005
Synonym. Longchengpterus zhaoi Wang et al., 2006
Emended Diagnosis. Istiodactylids that share the following features: slight dorsal deflection of the palatal anterior tip; orbit piriform; craniomandibular joint located under the anterior margin of the orbit; dentary symphysis about one-third the length of the mandible; dentary symphysis with gradual taper of the lateral margins; triangular, laterally compressed teeth lacking carinae; crowns with both labial and lingual slight concavities; slight constriction between tooth crown and root.
Nurhachius luei sp. nov.
urn:lsid:zoobank.org:act:6F93DC7F-20A7-4CBC-8A38-1D6C802A1906.
Etymology. The specific name luei (/lyi/) honors the late Prof. Junchang Lü, who has made great contributions to the study of Chinese pterosaurs.
Holotype. Skull, mandible and seven cervical vertebrae (BPMC-0204). The specimen is permanently deposited and available for researchers at a public repository, the Beipiao Pterosaur Museum of China, Beipiao, Liaoning Province, China (Fig. 1).
Type Locality and Horizon. Huanghuatan village, Dapingfang town, Chaoyang City, Liaoning Province, China (Fig. 2); lower part of the Jiufotang Formation, Early Cretaceous (Aptian).
Differential diagnosis. The new species is diagnosed based on the following features: quadrate inclined at 150°; medial process of the pterygoid broad and plate-like; dorsal median sulcus of the mandibular symphysis extending up to the first pair of mandibular teeth; dorsally directed odontoid (pseudotooth) of the mandibular symphysis, lacking a foramen on the lateral side and with a blunt occlusal surface; ceratobranchial I of the hyoids accounting for 60% of mandibular length; mandibular teeth extending distally beyond the symphysis.
Conclusions:
The new specimen here described represents the second species for the genus Nurhachius, previously restricted to its type-species N. ignaciobritoi. A slight dorsal deflection of the palatal anterior tip revealed to be a synapomorphy of N. ignaciobritoi and N. luei. That feature was previously thought to be restricted to the Anhangueria and Cimoliopterus. Unlike other pterodactyloids, the holotype of N. luei sp. nov. shows an anterolabial tooth replacement. The position of Hongshanopterus lacustris and Haopterus gracilis as close taxa to the Istiodactylids is supported by the performed phylogenetic analysis. Ikrandraco avatar and Lonchodraco giganteus resulted to be sister taxa, and closer to istiodactylids than to other lanceodontians. The phylogenetic analysis supports the reinterpretation of Archaeoistiodactylus linglongtaensis as a non-pterodactyloid monofenestratan, probably a wukongopterid.
Xuanyu Zhou, Rodrigo V. Pêgas3, Maria E.C. Leal and Niels Bonde. 2019. Nurhachius luei, A New Istiodactylid Pterosaur (Pterosauria, Pterodactyloidea) from the Early Cretaceous Jiufotang Formation of Chaoyang City, Liaoning Province (China) and Comments on the Istiodactylidae. PeerJ. 7:e7688. DOI: 10.7717/peerj.7688
New Pterosaur Was Fossilized with a Ridiculous Grin blogs.scientificamerican.com/laelaps/new-pterosaur-was-fossilized-with-a-ridiculous-grin via @sciam
