Notes on the Phylogeny of the Pelecaniformes
1947; Oxford University Press; Volume: 64; Issue: 1 Linguagem: Inglês
10.2307/4080063
ISSN1938-4254
Autores Tópico(s)Fish Biology and Ecology Studies
ResumoCERTAIN aspects of the phylogeny of the order Pelecaniformes are obscured by the arrangement of its three living suborders in fi•e standard classifications.The sequence as given by Wetmore (1940) and Peters (1931)is: PHAJ•THONTES (Tropic-birds), PELECANI (Pelicans, Boobies, Cormorants, Snake-birds), and FREGATAE (Frigatebirds).The tropic-birds and oerigate-birds, although widely divergent, show basic structural similarities which indicate both to be primitive members of the order, and which link the order with the Procellariiformes.The fundamental similarity of Phagthon and Fregata has been recognized in the older work on the comparative osteology of the group.Mivart (1878), from a study of the axial skeleton, came to the conclusion that Phagthon and Fregata possessed common characters which sharply distinguished them from the other steganopodes, and, in fact, could find no characters to unite them with the rest of the steganopodous genera to form a natural group.The generalized condition of the cervical vertebrae of these two genera, in contrast to the specialization in the rest of the order, and certain primitive skull characters are largely self-evident and may have escaped emphasis for this reason.Shuoeeldt (1894) states that" . . .Steganopodes are more closely connected with the Tubinares than they are with the Longipennes."Murphy (1936) recognizes the generalized character of the skull of Pha•'thon, and the affinity of the Pelecaniformes with the Procellariiformes; these two facts, at least, are implicit in modern classifications.The more obvious skeletal characters common to Pha•'thon and Fregata, and common also to the procellariiforms, may be summarized as follows: ¾omer present; maxillopalatines forming two conspicuous separate lobes on the palatal surface of skull near anterior end of palatines; occipital condyle well underneath skull, so that condyle is anterior to coronal crest.Fifteen cervical vertebrae present; normal, with serial change in shape gradual.Corresponding characters of the suborder Pelecani are: Vomer absent; maxillopalatines not visible on palatal surface, or (in Pelecanu$) visible on surface and lobed, but fused in midline and reduced.Occipital condyl½ in line with or posterior to the coronal crest.Seventeen to twenty cervical vertebrae; articulation of cervical vertebrae peculiar, eighth or ninth pressed back at pre-axial end; posterior forking of neural arches appearing suddenly on seventh or eighth vertebrae.The relationship of Phagthon and Fregata to each other and to
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