Some azhdarchids also appear to possess relatively slender rostra(A) ZIN PH 112/44, as indicated by the rostral fragment of Azhdarcho lancicollis showing concave dorsal skull margin of Azhdarcho (Fig. 8Afollowing Averianov, 2010); (B) anterior skull and mandible of TMM [http://sciencecasenetplayeatpartyproductions.orgcom/members/washerseason43shapepink4/activity/6129951077314/ UB R1083 humerus Erior (H) aspect (note specially {large] 42489-2, unnamed azhdarchid from the Javelina Formation, USA; (C) restored skull of Quetzalcoatlus sp. Scale bars represent 100 mm, except for a (10 mm).thick-walled cervicals of Hatzegopteryx, too as its typically reinforced bones and wide jaws (Buffetaut, Grigorescu Csiki, 2002; Buffetaut, Grigorescu Csiki, 2003), look much better suited to tackling bigger, more potent prey, or for utilizing greater force and violence when getting meals, than azhdarchid species with thin-walled bones, extended, gracile necks and narrow skulls. Undescribed fossils probably referable to Hatzegopteryx (like added skull and limb components that can't be described here) show that robust construction was consistent across its physique. The higher resistance to bending stresses and indications of significant cervical muscle tissues in Hatzegopteryx are consistent with this idea, as would be the inverse findings for Arambourgiania. Modern research on azhdarchid foraging behaviour recommend that they were terrestriallyforaging generalists (Witton Naish, 2008; Witton HabibNaish, 20102015; Carroll, Poust Varricchio, 2013; Witton, in press). The size What tiny is identified of] giant azhdarchid anatomy is similar enough to that with the smaller sized, superior recognized azhdarchids to assume that in addition they foraged terrest.Formation specimen TMM 42489-2), and gracile forms with elongate rostra and slender jaws (Quetzalcoatlus sp.; Zhejiangopterus; Alanqa). Some azhdarchids also seem to possess somewhat slender rostra, as indicated by the concave dorsal skull margin of Azhdarcho (Fig. 8A, Averianov, 2010). A third category issues the wing skeletons: we note that the reasonably abbreviated metacarpal IV and proximal wing phalanx on from the diminutive azhdarchid Montanazhdarcho minor contrasts markedly together with the elongate distal forelimb components elements of Quetzalcoatlus sp. and Zhejiangopterus (McGowen et al., 2002). It has been speculated that azhdarchids might could be roughly grouped into `robust' and `gracile' types forms based on these differences variations (Witton, 2013). It certainly seems proper appears suitable to think about forms consider types like Hatzegopteryx `robust' and others--e.g., Quetzalcoatlus and Zhejiangopterus--`gracile', but some taxa show `mixed' anatomies (e.g., Montanazhdarcho has proportionally stocky wing bones, but elongate neck bones (McGowen et al., 2002)), suggesting these categories must have to be regarded as considered loose. Azhdarchid physique plans might may have been rather much a lot more varied than imagined previously. Our assessment of vertebral mechanics in Hatzegopteryx and Arambourgiania suggests that azhdarchid necks had drastically various distinctive functional capabilities. We presume that cranial and cervical disparity reflects distinct foraging habits and prey preferences, with robust azhdarchids tackling somewhat bigger larger prey than their gracile counterparts. The stout,Naish and Witton (2017), PeerJ, DOI 10.7717/peerj.20/Figure 8 Azhdarchid disparity in cranial and limb anatomy. (A) ZIN PH 112/44, rostral fragment of Azhdarcho lancicollis showing concave dorsal skull margin (just soon after Averianov, 2010); (B) anterior skull and mandible of TMM 42489-2, unnamed azhdarchid in the Javelina Formation, USA; (C) restored skull of Quetzalcoatlus sp. (determined by depending on Kellner Langston Jr, 1996); (D) skull of Zhejiangopterus linhaiensis (determined by based on Cai Wei, 1993); (E) MOR 69I, Montanazhdarcho minor holotype pectoral girdle and left forelimb (note stunted metacarpal IV); (F) M1323 postcrania of Z. linhaiensis. Abbreviations: car or truckvehicle, carpals; cer, cervical vertebrae; cor, coracoid; fem, femur; hum, humerus; mcIV, metacarpal IV; pt, pteroid; rad, radius; tib, tibia; ul, ulna; wpI, wing phalanx I. Scale bars represent one hundred mm, except for any (ten mm).thick-walled cervicals of Hatzegopteryx, as well as its commonly reinforced bones and wide jaws (Buffetaut, Grigorescu Csiki, 2002; Buffetaut, Grigorescu Csiki, 2003), appear improved suited to tackling bigger, extra strong prey, or for using higher force and violence when obtaining food, than azhdarchid species with thin-walled bones, extended, gracile necks and narrow skulls. The higher resistance to bending stresses and indications of large cervical muscles in Hatzegopteryx are constant with this concept, as would be the inverse findings for Arambourgiania.Formation specimen TMM 42489-2), and gracile types with elongate rostra and slender jaws (Quetzalcoatlus sp.; Zhejiangopterus; Alanqa). Some azhdarchids also appear to have comparatively slender rostra, as indicated by the concave dorsal skull margin of Azhdarcho (Fig. 8A, Averianov, 2010). A third category issues the wing skeletons: we note that the somewhat abbreviated metacarpal IV and proximal wing phalanx from the diminutive azhdarchid Montanazhdarcho minor contrasts markedly together with the elongate distal forelimb elements of Quetzalcoatlus sp. and Zhejiangopterus (McGowen et al., 2002). It has been speculated that azhdarchids could be roughly grouped into `robust' and `gracile' forms depending on these variations (Witton, 2013). It certainly appears suitable to consider forms like Hatzegopteryx `robust' and others--e.g., Quetzalcoatlus and Zhejiangopterus--`gracile', but some taxa show `mixed' anatomies (e.g., Montanazhdarcho has proportionally stocky wing bones, but elongate neck bones (McGowen et al., 2002)), suggesting these categories should be deemed loose. Azhdarchid body plans may have been rather more varied than imagined previously. Our assessment of vertebral mechanics in Hatzegopteryx and Arambourgiania suggests that azhdarchid necks had drastically unique functional capabilities.
