Psilopterus lemoinei (Moreno & Mercerat, 1891)

Alvarenga, Herculano M. F. & Höfling, Elizabeth, 2003, Systematic Revision Of The Phorusrhacidae (Aves: Ralliformes), Papéis Avulsos de Zoologia 43 (4), pp. 55-91 : 81-83

Psilopterus lemoinei (Moreno & Mercerat, 1891)

comb. n.

Patagornis lemoinei Moreno & Mercerat, 1891 (pp. 23 and 58).

Psilopterus australis Moreno & Mercerat, 1891 (pp. 26 and 68); Brodkorb, 1967.

Pelecyornis tubulatus Ameghino, 1895 ; Brodkorb, 1967 (syn. of Psilopterus australis ).

Phororhacos modicus Ameghino, 1895; syn.n.

Staphylornis gallardoi Mercerat, 1897 ; Brodkorb, 1967 (syn.? of Psilopterus australis ).

Staphylornis erythacus Mercerat, 1897 ; Brodkorb, 1967 (syn.? of Psilopterus australis ).

Pelecyornis tenuirostris Sinclair & Farr, 1932 ; Brodkorb, 1967 (syn. of Psilopterus australis ).

Lectotype – (by present designation): Distal end of a right tibiotarsus (MLP-162).

Hypodigm – Besides the lectotype and the material that served as type for the diverse synonyms, a plentiful and splendid material is discribed and pictured by Sinclair & Farr (1932). An ungual phalanx (MLP-164), described and pictured by Moreno & Mercerat (1891) as belonging to this species, certainly belongs to Patagornis marshi .

Horizon and Locality – Middle Miocene (Santacrucian) of Argentina, Santa Cruz Province: Santa Cruz, Killik Aike, Monte Observación, Take Harvey, La Cueva, Corriguen Kaik, Tagua Quemada .

Diagnos i s Revised – Larger-sized than P. bachmanni ( Fig. 1F ), with the skull and upper maxilla notably higher ( Figs. 26F, 26H and 26I ), and a less slanted rostral edge of the antorbital fenestra. Other differences in the diverse segments of the skeleton are described and pictured by Sinclair & Farr (1932).

Measurements – Table 8 and Sinclair & Farr (1932).

8. Measurements of the Psilopterinae (mm). Numbers in brackets are estimates based on incomplete bones.

Illustrations – Sinclair & Farr (1932).

Remarks – One of the best represented Phorusrhacidae by the relative abundance of fossils. Some observed discrepancies, especially in the skulls ( Figs. 26F, 26G, 26H and 26I ), should be attributed to differences in age or sex. Psilopterus lemoinei and P. bachmanni are herein dealt with as being two very similar species that appear to have lived together, disputing very similar niches. The most important difference between the two is in the size and proportions of the upper maxilla, and the differences in slant of the rostral edge of the antorbital fenestra. A deeper study might lead to different conclusions, as to the number of species of the genus Psilopterus from the Santacruzian of Argentina, as was discussed before under the sub-title: “intra-specific variations”.

Figures

FIGURE 1. Reproduction (by E. Brettas) of some Phorusrhacidae keeping the due proportion as to size. The silhouette of a man 1.75 m high is used as a scale. A - Brontornis burmeisteri; B - Paraphysornis brasiliensis; C - Phorusrhacos longissimus; D - Andalgalornis steuletti; E - Psilopterus bachmanni; F - Psilopterus lemoinei; G - Procariama simplex; H - Mesembriornis milneedwardsi.

FIGURE 26. Skulls of the Patagornithinae (A-C), Mesembriornithinae (D) and Psiloterinae (E-J). A - Andrewsornis abbotti (FM-P13417; from Patterson, 1941), B - Patagornis marshi (BMNH-A-516; from Andrews, 1899), C - Andalgalornis steulleti (FM-P14357); D - Mesembriornis milneedwardsi (MMP-S155); E - Procariama simplex (FM-P14525); F - Psilopterus lemoinei (FM-P13257); G - Psilopterus lemoinei (PUM-15402); H - Psilopterus lemoinei (AMNH-9157); I - Psilopterus lemoinei (PUM-15109); J - Psilopterus bachmanni (PUM-15904). G-J inverted figures from Sinclair & Farr (1910).