Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 Sep 26;12(9):e0185486.
doi: 10.1371/journal.pone.0185486. eCollection 2017.

The Toothless Pterosaur Jidapterus Edentus (Pterodactyloidea: Azhdarchoidea) From the Early Cretaceous Jehol Biota and Its Paleoecological Implications

Affiliations
Free PMC article

The Toothless Pterosaur Jidapterus Edentus (Pterodactyloidea: Azhdarchoidea) From the Early Cretaceous Jehol Biota and Its Paleoecological Implications

Wen-Hao Wu et al. PLoS One. .
Free PMC article

Abstract

Background: In the Early Cretaceous Jehol Biota, the toothless pterosaurs flourished with the chaoyangopterids and tapejarids playing a key role in understanding the early diversity and evolution of the Azhdarchoidea. Unlike the more diverse tapejarids, the rarer chaoyangopterids are characterized by a long and low rostrum, supporting a close relationship with the huge azhdarchids. Unfortunately, our knowledge is still limited in the osteology, paleoecology, and taxonomy of the Chaoyangopteridae. As one of the best preserved skeletons, the type and only specimen of Jidapterus edentus provides an opportunity to understand the morphology and paleoecology of the chaoyangopterids.

Results: Our study of the osteology of Jidapterus edentus reveals valuable information about the morphology of the Chaoyangopteridae such as a rostrum with a curved dorsal profile, high Rostral Index (RI), larger angle between the dorsal and postorbital processes of the jugal, sequentially shorter fourth to seventh cervical vertebrae, sternum with a plate wider than long, contact of the metacarpal I with the distal syncarpal, pneumatic foramen on first wing phalanx, hatchet-like postacetabular process with unconstricted neck and small dorsal process, distinctly concave anterior margin of pubis, subrectangular pubic plate with nearly parallel anterior and posterior margins, longer proximal phalanges of pedal digits III and IV, as well as reduced and less curved pedal unguals. These features further support the validity of Jidapterus edentus as a distinct species and the close relationship of the chaoyangopterids with the azhdarchids. Paleoecologically, the chaoyangopterids are probably like the azhdarchids, more terrestrial than the contemporaneous and putatively arboreal tapejarids, which may have been limited to the forest-dominated ecosystem of the Jehol Biota.

Discussion: The osteology of Jidapterus edentus further supports the close relationship of the Chaoyangopteridae with the Azhdarchidae in sharing a high RI value and reduced and mildly-curved pedal unguals, and it also implies a possible paleoecological similarity in their terrestrial capability. Combined with the putatively arboreal and herbivorous tapejarids, this distinct lifestyle of the chaoyangopterids provides new insights into the diversity of pterosaurs in the ecosystem of the Jehol Biota.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Fig 1
Fig 1. Entire skeleton of Jidapterus edentus (RCPS-030366CY) preserved in a slab mostly in right lateral view.
Abbreviations: aa, the atlas-axis complex; bo, basioccipital; br, braincase; cve, cervical vertebrae; cv3, the third cervical vertebra; cv8, the eighth cervical vertebra; ds, dentaries; dv, dorsal vertebra; dve, dorsal vertebrae; ep, epiphysis; j, jugal; lc, left carpus; lf, left femur; li, left ilium; lis, left ischium; lm, left manual digits; lp, left pubis; lpe, left pes; lpt, left pteroid; lr, left radius; lsc, left scapula-coracoid; lt, left tibia; lta, left tarsus; lu, left ulna; lwmc, left wing metacarpal; lwp1–4; left wing phalanges 1–4; p, pterygoid; pp, postacetabular process of the right ilium; q, quadrate; rc, right carpus; rh, right humerus; rf, right femur; rfi, right fibula; ribs, ribs; ris, right ischium; rm, right manual digits; rmcI, right metacarpal I; rp, right pubis; rpe, right pes; rpt, right pteroid; rr, right radius; rsc, right scapula-coracoid; rt, right tibia; ru, right ulna; rwmc, right wing metacarpal; rwp1–4, right wing phalanges 1–4; rostrum, rostrum; st, sternum; sv, sacral vertebra; sve, sacral vertebrae. Gray shaded areas bound by solid lines indicate preserved bones, dashed lines indicate bones with margins discerned by impression, and lack of lines indicate missing bone or displacement along cracks in the slab.
Fig 2
Fig 2. Rostrum in right lateral view (A, B) and lower jaws mostly in ventral view (C, D) of Jidapterus edentus (RCPS-030366CY).
Abbreviations: ds, dentaries; lmr, labial margin of the rostrum; lrpp, a low ridge of the premaxillary process; lrr, a low ridge of rostrum; naf, nasoantorbital fenestra; slt, shallow longitudinal trough. Gray shaded areas bound by solid lines indicate preserved bones and the dark gray area indicates shallow longitudinal trough (slt).
Fig 3
Fig 3. Disarticulated cranial elements, atlas-axis complex, and postcranial elements of Jidapterus edentus (RCPS-030366CY).
Abbreviations: at, atlas; ax, axis; bo, basioccipital; j, jugal; lf, left femur; lt, left tibia; pp, postacetabular process of the right ilium; q, quadrate; rsc, right scapula. Gray shaded areas bound by solid lines indicate preserved bones, and dashed lines or lack of lines indicate missing bone.
Fig 4
Fig 4. Enlarged images of endocast (A), third cervical vertebra in dorsal view (B), fourth cervical vertebra in right lateral view (C), and distal ends of femora in posterior view (D) of Jidapterus edentus (RCPS-030366CY).
Abbreviations: lf, distal portion of the left femur; lt, proximal portion of the left tibia; rf, distal portion of the right femur. Scale bar = 10 mm.
Fig 5
Fig 5. Sacral vertebrae and sternum in ventral view as well as the disarticulated pelvic girdle in medial view of Jidapterus edentus (RCPS-030366CY).
Abbreviations: cr, cristospine; lf, left femur; li, left ilium; lis, left ischium; lp, left pubis; of, obturator foramen; rf, right femur; ris, right ischium; st, sternum; sv, sacral vertebra;? il, possible ilium fragment. Gray shaded areas bound by solid lines indicate preserved bones, dashed lines indicate bones with margins discerned by impression, and lack of lines indicate missing bone.
Fig 6
Fig 6. Left manus in ventral view (A) and right manus in dorsal view (B) of Jidapterus edentus (RCPS-030366CY).
Abbreviations: A, sesamoid A; dc, distal carpals; etp, extensor process; lmcI–III, left metacarpals I–III; lr, left radius; lu, left ulna; lwmc, left wing metacarpal; lwp1, the left first wing phalanx; mdI–III, manual digits I–III; pn, pneumatic foramen; prc, preaxial carpal; pt, pteroid; rc, radial carpal; rmcI, right metacarpal I; rmdI–III, right manual digits I–III; rr, right radius; ru, right ulna; rwmc, right wing metacarpal; rwp1–2, right wing phalanx 1 and 2; uc, ulnar carpal. Gray shaded areas bound by solid lines indicate preserved bones, dashed lines indicate bones with margins discerned by impression, and lack of lines indicate missing bone or displacement along cracks in the slab.
Fig 7
Fig 7. Left pes in ventral view (A, B) and right pes in dorsal view (C, D) of Jidapterus edentus (RCPS-030366CY).
Abbreviations: ldta, left distal tarsal; lmtI–V, left metatarsals I–V; lpdI–V, left pedal digits I–V; lpta, left proximal tarsal; lt, left tibia; rmtI–V, right metatarsals I–V; rpdI–IV, right pedal digits I–IV. Gray shaded areas bound by solid lines indicate preserved bones, dashed lines indicate bones with margins discerned by impression, and lack of lines indicate missing bone or obscuring by overlying bones.
Fig 8
Fig 8. Cladogram depicting the evolutionary relationships of the Azhdarchoidea from the phylogenetic analysis of Jidapterus edentus and the Pterosauria.
TNT node numbers are depicted below the branches that subtend the nodes. Branch lengths and support measures are listed in S1 Table.
Fig 9
Fig 9. Box plots for the ungual curvature of pedal digit III of azhdarchoids and extant tetrapods.
The box plots performed by PAST 2.12 [77], and the extant data from Birn-Jeffery et al. [78].
Fig 10
Fig 10. Box plots for the limb proportions of azhdarchoids.
The box plots performed by PAST 2.12 [77], and data from Table 2. Chaoyangopterids (brown), tapejarids (dark blue), Microtuban (purple square), azhdarchids (red diamond), and Tupuxuara (light blue triangle).

Similar articles

See all similar articles

Cited by 1 article

References

    1. Wellnhofer P. The Illustrated Encyclopedia of Pterosaurs. London: Salamander Books; 1991.
    1. Unwin DM. The Pterosaurs from Deep Time. New York: Pi Press; 2005.
    1. Witton MP. Pterosaurs: Natural History, Evolution, Anatomy. Princeton and Oxford: Princeton University Press; 2013.
    1. Nessov LA. Upper Cretaceous pterosaurs and birds from Central Asia. Paleontologicheskii Zhurnal. 1984; 1: 47–57.
    1. Lü J, Unwin DM, Xu L, Zhang X. A new azhdarchoid pterosaur from the Lower Cretaceous of China and its implications for pterosaur phylogeny and evolution. Naturwissenschaften. 2008; 95: 891–897. doi: 10.1007/s00114-008-0397-5 - DOI - PubMed

Grant support

This study is supported by the Public Science and Technology Research Funds Projects of Land and Resources of China (No. 201311120) and Liaoning Baiqianwan Talents Program (No. 2014Q110) to CFZ, and National Natural Science Foundation of China (No. 41202012) to WHW. The funders had no role in study design, data collection and analysis, decision to pulish, or preparation of the manuscript.
Feedback