Physornis Ameghino, 1895
publication ID |
https://doi.org/ 10.1590/S0031-10492003000400001 |
persistent identifier |
https://treatment.plazi.org/id/03D18A23-C849-1853-5A62-29329577FA3D |
treatment provided by |
Carolina |
scientific name |
Physornis Ameghino, 1895 |
status |
|
Genus Physornis Ameghino, 1895
Physornis Ameghino, 1895:576 ; Brodkorb, 1967. Aucornis Ameghino, 1898:9 ; Brodkorb, 1967 (syn. of
Physornis ).
Type Species – Physornis fortis Ameghino, 1895 .
Included Species – Only the type species.
Distribution – Middle and Upper Oligocene of Argentina.
Diagnosis Revised – Of a gigantic size, rivaling with Brontornis . A very short and wide mandibular symphy- sis, characteristically with an almost flat ventral surface in the mid-portion ( Fig. 12 View FIGURE 12 and e. g. Alvarenga, 1993: Fig. 1 View FIGURE 1 ). The lateral cotyl of the tarsometatarsus is almost quadrangular, when viewed proximally ( Fig. 13A View FIGURE 13 ). The lateral edge of the hipotarsus, when viewed from the rear, forms a prominent crest which distiguishes it well from Brontornis and Paraphysornis ( Fig. 13 View FIGURE 13 and e. g. Alvarenga, 1993: Fig. 2 View FIGURE 2 ).
Remarks – The genus Physornis and its type species P. fortis , were described by Ameghino in 1895, based on a fragment of the mandible comprehending part of the symphysis and the right branch, this description, unfortunately, not being accompanied by an illustration.
Patterson (1941:52) examined the type of Physornis fortis , nowadays deposited in the museum of London (BMNH-A583), arriving at the conclusion that this is a bony fragment without any morphological characteristic, possibly being the iliac crest of a mammal, thus proposing the rejection of the terms, both for the genus as well as the species, as being indeterminate. We had also the opportunity of examining the aforementioned type material ( Fig. 14 View FIGURE 14 ), arriving at the Hypodigm – Type; a mandibular symphysis, including a part of the left branch ( Figs. 12 View FIGURE 12 A-C), associated to the caudal portion of the left quadratojugal ( Fig. 15A View FIGURE 15 ), and to the atlas ( Fig. 16A View FIGURE 16 ), besides fragments of vertebras, phalanges etc. (FM-P13340). A well conserved madibular symphysis ( Fig. 12D View FIGURE 12 ), associated to the caudal extremity of the right quadratojugal (FM-P13619). conclusion that this is undoubtedly a fragment of the symphysis and part of the right branch of a large Phorusrhacidae . The experience acquired in the restoration of the mandible of Paraphysornis (Alvarenga, 1982) , contributed to us for the immediate recognition of the texture of a real mandibular symphysis of a Phorusrhacidae . Further, it is evident that Ameghino had prior experience, having examined and described several other mandibular symphysis of Phorusrhacidae , such as, Phorusrhacos longissimus Ameghino, 1887 ; Phororhacos sehuensis Ameghino, 1891; Phororhacos platygnathus Ameghino, 1891; Tolmodus inflatus Ameghino, 1891 , and others, this showing his intimacy with this anatomical portion, which, apparantly, is often conserved in the Phorusrhacidae fossils.
Although it is an almost shapeless fragment and, thus, very inadequate for typifying a species, the type demonstrates, besides the size and the geographical and stratigraphical source, also the flat portion of the ventral surface of the mandibular symphysis, which is characteristic of this genus ( Figs. 12A View FIGURE 12 and 14 View FIGURE 14 ).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.