Bennett 2017 described AMNH 4908:
“The smallest relatively complete previously known specimen of Pteranodon, AMNH 4908, consists of a partial trunk skeleton and tail, scapulocoracoid, humerus through WP2, both femora and tibiae, and a disarticulated foot (Bennett, 2001; Table 1), had an estimated wingspan in life of 3.33 m.”
AMNH 4908 is small because
it is primitive (Figs. 1–3), closer to its smaller germanodactylid ancestors (Fig. 4), not because it is ontogenetically young. That point was overlooked by Bennett 2017 who decided not to include a comprehensive phylogenetic analysis then or earlier (Bennett 1991, 1992). He thought smaller specimens, like AMNH 4908, were female.
It is worth noting
AMNH 4908 has a type of pelvis with unfused ischia, a morphology common to Nyctosaurus. Earlier Bennett 1991, 1992 decided a large Nyctosaurus pelvis belonged to a female Pteranodon, which started that gender myth. Unfortunately, Bennett never used phylogenetic analysis to lump and split Pteranodon, the subject of his 1991 PhD thesis. Instead he relied on a statistical analysis, which led him astray. The large pterosaur tree (LPT, 246 taxa) is the only published pterosaur cladogram to include more than one or two Pteranodon and Nyctosaurus taxa. When you really want to know something in systermatics, use a comprehensive cladogram, not a graph.
Also worth noting
is the deltopectoral crest of the humerus in AMNH 4908, which has a round tongue shape like that of its predecessors among Eopteranodon and Germanodactylus (Fig. 4), rather than the hatchet shape found in Nyctosaurus or the warp found in Pteranodon.
Of course, any taxon basal to Nyctosaurus and Pteranodon
is also going to be close to the SMNK PAL 6592 specimen (Fig. 4) attributed to Germanodactylus.
Ever since 2003, traditional pterosaur workers (with PhDs)
have been linking toothless pteranodontids to toothy ornithocheirids. That they continue to do so, (due to taxon exclusion) is embarrassing to the profession.
In similar fashion and shame,
traditional paleontologists continue to insist that pterosaurs arose from Euparkeria, Scleromochlus or Erythrosuchus according to several authors, or from Macrocnemus bassanii, Postosuchus kirkpatricki and Herrerasaurus ischigualastensis according to Dalla Vecchia 2019. More closely related taxa (Langobardisaurus, Cosesaurus, Sharovipteryx and Longisquama) were validated as better pterosaur ancestors in four phylogenetic analyses 20 years ago.
Bennett SC 1991. Morphology of the Late Cretaceous Pterosaur Pteranodon and Systematics of the Pterodactyloidea. [Volumes I & II]. Ph.D. thesis, University of Kansas, University Microfilms International/ProQuest.
Bennett SC 1992. Sexual dimorphism of Pteranodon and other pterosaurs, with comments on cranial crests. Journal of Vertebrate Paleontology 12: 422–434.
Bennett SC 2017. New smallest specimen of the pterosaur Pteranodon and ontogenetic niches in pterosaurs. Journal of Paleontology. pp.1-18. 0022-3360/15/0088-0906
Dalla Vecchia FM 2019. Seazzadactylus venieri gen. et sp. nov., a new pterosaur (Diapsida: Pterosauria) from the Upper Triassic (Norian) of northeastern Italy. PeerJ 7:e7363 DOI 10.7717/peerj.7363
Thanks to Alex Schiller for posting this specimen on Facebook.