Cal skeleton, at the same time as in neighbouring cranial or torso skeletal components; this was surely linked together with the anchoring of powerful neck musculature and large ligaments in the base and XMD8-92 biological activity anterior finish in the neck. semispinalis capitis/spinocapitis posticus). Similarly, the broken basioccipital tuberosities of Hatzegopteryx are lengthy even as preserved: neck and head flexors anchoring to these (m. longissimus capitis profundus, m. rectus capitisventralis) would have had high mechanical advantage. The length and size of those occipital options recommend that large muscle tissues with augmented lever arms have been anchored to the azhdarchid skull. Witmer et al. (2003) and Habib Godfrey (2010) made related observations in regards to the occipital regions of other pterodactyloids: at least the anterior neck skeleton of pterosaurs was probably strongly muscled. In the other intense from the axial column, the azhdarchid scapulocoracoid suggests that their superficial neck musculature may perhaps happen to be nicely developed. Their scapulae are significant and dorsoventrally expanded in comparison to those of other pterosaurs (e.g., Elgin Frey, 2011), permitting broad insertions of m. levator scapulae and m. serratus (Bennett (2003) shows their probably origin in other pterosaurs). These muscles originate on the anterior cervicals in modern reptiles and can function as neck elevators and retractors in the event the scapulae are immobile. Azhdarchid scapulocoracoids articulated tightly together with the dorsal vertebrae and sternum (Frey, Buchy Martill, 2003) and were buried within deep flight musculature, so have been likely capable of small, if any, motion. Contraction of cervical-pectoral muscle groups would thus probably elevate the neck, and asymmetric contraction of these muscles would move the neck laterally. These muscles (or homologues thereof) are specifically significant in long-necked, large-headed mammals like horses and deer (Goldfinger, 2004.Cal skeleton, too as in neighbouring cranial or torso skeletal components; this was surely associated together with the anchoring of potent neck musculature and significant ligaments in the base and anterior end of the neck. They are optimal positions from which to support and operate long necks. In view of this, the elongate and tubular, somewhat immobile mid-series vertebrae of azhdarchids ought to be viewed as a pronounced development of a skeletal adaptation common across tetrapods, not as an unusual or unprecedented anatomical configuration. Azhdarchid skeletons show ample attachment web pages for neck musculature. As an example, the occiput of Hatzegopteryx shows obvious indicators of substantial soft-tissue attachment: the nuchal line is properly developed and extended, and its dorsolateral edges are deeply dished andNaish and Witton (2017), PeerJ, DOI 10.7717/peerj.17/marked with vertical scarring (Buffetaut, Grigorescu Csiki, 2002; Buffetaut, Grigorescu Csiki, 2003). Comparison with extant reptile anatomy Herrel De Vree, 1999; Cleuren De Vree, 2000; Tsuihiji, 2005; Tsuihiji, 2010; Snively Russell, 2007; Snively et al., 2014 suggests that these capabilities reflect significant insertion locations for transversospinalis musculature (specifically m. transversospinalis capiti and the m. epistropheo-capitis/splenius group), cervical musculature devoted to head and neck extension and lateral flexion. The significant neural spines on posterior azhdarchid cervicals and anterior thoracic vertebrae offer potential origin web-sites for m. transversospinalis capiti, while the lengthy neural spine of cervical III probably anchored m. epistropheo-capitis. The opisthotic approach of Hatzegopteryx is poorly identified but was evidently significant and robust and likely facilitated attachment of massive neck extensors and lateral flexors (m.