Phorusrhacos longissimus Ameghino, 1887

Alvarenga, Herculano M. F. & Höfling, Elizabeth, 2003, Systematic Revision Of The Phorusrhacidae (Aves: Ralliformes), Papéis Avulsos de Zoologia 43 (4), pp. 55-91 : 72-73

Phorusrhacos longissimus Ameghino, 1887

Phorusrhacos longissimus Ameghino, 1887:24 ; Brodkorb,

1967. Phororhacos longissimus Ameghino, 1889:659 . Stereornis rollieri Moreno & Mercerat, 1891:21 , 45;

Brodkorb, 1967 (syn. of P. longissimus ). Stereornis gaundryi Moreno & Mercerat, 1891 :21,47;

Brodkorb, 1967 (syn. of P. longissimus ). Mesembriornis studeri Moreno & Mercerat, 1891:21 , 48;

Brodkorb 1967 (syn. of P. longissimus ). Mesembriornis quatrefragesi Moreno & Mercerat, 1891:22 ,

50; Brodkorb, 1967 (syn. of P. longissimus ). Darwinornis copei Moreno & Mercerat, 1891:24 , 60;

Brodkorb, 1967 (syn. of P. longissimus ). Darwinornis zittelli Moreno & Mercerat, 1891:25 , 63; Brodkorb, 1967 (syn. of P. longissimus ). Darwinornis socialis Moreno & Mercerat, 1891:25 , 63;

Brodkorb, 1967 (syn. of P. longissimus ). Owenornis affinis Moreno & Mercerat, 1891:25 , 64;

Brodkorb, 1967 (syn. of P. longissimus ).

the distal portion of the mid-trochlea not being laterally expanded as is the case of Titanis ( Fig. 22 ).

Remarks – Within the subfamily, Phorusrhacos is that which possesses the largest amount of fossils, these coming from the Santacruzian sediments in Argentina. To elaborate a more detailed anatomical diagnosis which would separate Phorusrhacos from both Devincenzia and Titanis becomes, however, difficult through the deficiency in material, seeing that the latter two genera are very badly represented. It is worthwhile pointing out that Devincenzia , with a size which appears to exceed that of Phorusrhacos , comes from more recent levels of Argentina and Uruguay, whereas Titanis , with the same size, is only known from a still more recent terrain of North America.

Owenornis lydekkeri Moreno & Mercerat, 1891: 25, 64; Brodkorb, 1967 (syn. of P. longissimus).

Phororhacos sehuensis Ameghino, 1891: 258; Brodkorb, 1967 (syn. of P. longissimus).

Phororhacos platygnathus Ameghino, 1891: 452; Brodkorb, 1967 (syn. of P. longissimus).

Titanornis mirabilis Mercerat, 1893: 5; Brodkorb, 1967 (syn. of P. longissimus).

Callornis giganteus Ameghino, 1895: 78; Brodkorb, 1967 (syn. of P. longissimus).

Eucallornis giganteus Ameghino, 1901: 78; Brodkorb, 1967 (sin. of P. longissimus).

Liornis floweri Ameghino, 1895; syn. n.

Liornis minor Dolgopol de Saez, 1927; syn. n.

Type – A mandibular symphysis, including part of the right mandibular branch, but lacking the rostral extremity, MLP-118 (originally described as the mandible of a toothless mammal).

Hypodigm – Type; several segments of skeletons which served as the type for the various synonyms of the species (MLP-119 to 139, 171 to 182). The species is known from segments of almost all the skeleton, there lacking, however, a better representation of the skull. Ameghino (1895) tells of the observation and measurements of the skull of a specimen in nature, in fragments and encrusted in crumbling rock. The mandible, the rostral extremity of the upper maxilla and a fragment apparently from the caudal portion of the supra-orbital process ( BMNH-A529 , Figs. 18A , 23B, 23C , 24A and 24C ), coming from this specimen, were collected. Several other segments of the mandible represent the species ( Figs. 18 and 19 ). For P. longissimus there is still lacking an appropriate number of associated bones for a whole reconstruction of the bird. The specimen AMNH-9146 ( Fig. 20 ) represents an almost complete left tarsometatarsus, and the AMNH-9497 ( Fig. 21 ) is represented by some associated bones of a leg .

Horizon and Locality – Lower and Middle Miocene (Santacrucian) of Argentina; Santa Cruz Formation, the Province of Santa Cruz: La Cueva, Tagua Quemada, Monte Observación, Rio Shehuen .

Measurements – Table 5; Moreno & Mercerat, 1891; Ameghino, 1895.

Illustrations – Moreno & Mercerat, 1891 and Ameghino, 1895.

Figures

FIGURE 18. Mandibular symphysis of Phorusrhacos longissimus in dorsal view: A - BMNH-A 529; B - BMNH-A 530; C - BMNH-A 684.

FIGURE 19. Incomplete mandible of Phorusrhacos longissimus (BMNH-A530) in left lateral view.

FIGURE 20. Phorusrhacos longissimus (AMNH-9146).Left tarsometatarsus from Cañon de Las Vacas, Province of Santa Cruz, Argentina. Dorsal view. Maximum length 362 mm, calculated at 370 mm if it were complete.

FIGURE 21. Phorusrhacos longissimus (AMNH-9497). Associated bones of the left leg, coming from Monte Leon, Province of Santa Cruz, Argentina. A - Ventral view of the tibiotarsus, lacking the proximal end. B - Dorsal view of the femur, lacking a segment of the diaphysis. C - Phalanges (also assigned to the left foot). It was based on these bones that an estimate of the total length of the femur (around 31 cm) and of the tibiotarsus (nearly 50 cm), were made.

FIGURE 22. Right tarsometatarsus (distal end) of the Phorusrhacinae: A - Devincenzia pozzi (type: MACN-6554); B - Phorusrhacos longissimus (MLP-132) and C - Titanis walleri (type: UF-4108).Dorsal (above) and plantar (below) views.Note in Titanis a widening of the transverse diameter on the distal end of the midtrochlea.

FIGURE 23. A - Restoration of the skull of Devincenzia pozzi, modified by Patterson & Kraglievich (1960), based on specimen MLP-37-11-7-8 (type of Onactornis pozzi Cabrera, 1939). B and C - Phorusrhacos longissimus, drawing by Ameghino (1895), based on a “complete skull, but in such a bad state of conservation that it is almost reduced to dust” (BMNH-A529); C - dorsal view of the mandible. The skulls of both Phorusrhacinae are of approximately the same size, and differences in height can, at least partially, be attributed to deformation in fossilization and defects in the reassembling of the skull of Devincenzia pozzi.

FIGURE 24. Phorusrhacos longissimus. A - Caudal portion of the supraorbital processes of the lacrimal (?) (BMNH-A529). B and C - Fragments corresponding to the apex of the upper maxilla, respectively: BMNH-A529 and BMNH-A535. A and B belong to the same specimen mentioned in figures 23B and 23C.