The middle ear of the skull of birds: the Pelecaniformes and Ciconiiformes

Abstract

The anatomy of the middle ear region of the skull is described for the families of the Avian orders Pelecaniformes and Ciconiiformes. Emphasis is placed on the foramina and paths of the nerves and blood vessels. The morphology of the basicranium and quadrate is also discussed. Comparative analyses of the characters are used to assess taxonomic conclusions. Extant Pelecaniformes consist of six families, four of which are monogenic: Phaethontidae, Pelecanidae, Anhingidae and Fregatidae; one is composed of two genera: Sulidae; and the last has three genera: Phalacrocoracidae. Several years ago a relationship was suggested which would ally the Phaethontidae and the Fregatidae. While these families share several non middle ear characters the anatomy of the middle ear is not compatible with any particular relationship. Indeed, several obvious differences are described. The data presented here are consistent with the idea that the Phaethontidae and the Fregatidae each form a separate group of Pelecaniform birds, with the rest of the families forming a third group. Several differences in the middle ear region of the species of Anhingidae suggest that the family may be composed of two genera. While sharing many Ciconiiform characters the Ciconiidae have been shown not to be as closely related to the Ardeidae as they are to other families of Ciconiiformes. In addition, evidence is presented to support the recent idea that the three species of ibis (I. ibis, I. cinereus and I. leucocephalus) be united within the genus Mycteria. Also supported is the notion that Balaeniceps is Pelecaniform in character, and not Ciconiiform.

Die phylogenetischen Beziehungen des Schuhschnabels (Balaeniceps rex)

“…(15) Recessus tympanicus dorsalis enlarged, situated rostrally or laterally to the articular facets of the quadrate (Saiff 1978). (44) Musculus flexor cruris lateralis, pars accessoria absent.…”

“…Usually the recessus tympanicus is small and situated between the articular facets of the quadrate. This character was incorrectly coded as present for the Hydrobatidae by Cracraft (1985) (see also Saiff 1978); it is further absent in some Procellariidae (e. g. Bulweria bulwerii).…”

“…Cottam (1957) did not clearly state to which pelecaniform taxon she considered Balaeniceps to be most closely related, but indicated that it should be placed "possibly near the Pelecanidae". On the basis of a study of the middle ear region Saiff (1978) also concluded that the shoebill was more closely related to pelecaniform than to ciconiiform birds, and Olson (1979) noted that "it appears possible that the Balaenicipitidae, Scopidae and Ciconiidae may represent a more or less natural assemblage having affinities with the Pelecaniformes". However, Feduccia (1977) thought that the Balaenicipitidae were the sister taxon of the Ciconiidae because both taxa shared a similar derived morphology of the columella (ear ossicle).…”

Development of the paratympanic pneumatic system of Japanese quail

“…The images are modified from Tahara and Larsson (2019) extension into the surrounding bones at a later developmental stage, a process called (secondary) pneumatization given that pneumatization of bones are often evident as smooth walled recesses, fossae, or foramina. These external pneumatic morphologies have been studied in a wide range of birds (e.g., Norberg, 1978;Saiff, 1974Saiff, , 1976Saiff, , 1978Saiff, , 1981Saiff, , 1982Saiff, , 1988Saiff, , 2006Saiff, , 2011Starck, 1995;Vorster & Starck, 2003).…”

Molecules vs. morphology in avian evolution: the case of the "pelecaniform" birds.

“…However, this was not the first suggestion of a close relationship between pelicans and the Shoebill. In addition to the study by Saiff (4), noted above, Cottam (8) Sequence alignment was performed with ESEE (13), and the two sequenced regions were combined for all analyses. The aligned sequences were analyzed with MEGA (14).…”