Megascops guildayi

Megascops guildayi (Brodkorb and Mourer-Chauviré 1984)

Material. USNM PAL 641984, r ulna: shaft and proximal end, collected in 1991 (Fig. 1O).

USNM PAL 641985, r ulna: distal articular end only, collected October 2, 1996.

USNM PAL 769089, l femur: proximal 2/3, collected Sept. 22, 1994 (Fig. 1M).

CM 8040 holotype, l tarsometatarsus lacking proximal end. Not reexamined for this study.

USNM PAL 769088, pedal phalanx: entire, collected Sept. 22, 1994.

USNM PAL 641981, ungual phalanx: entire, collected Sept. 22, 1994.

Description. The bones of a strigid owl listed above are referred to M. guildayi based primarily on the criteria of size (smaller than Asio otus, larger than Megascops asio and M. kennicottii) and agreement in morphological details with modern Megascops. The proximal half of the ulna agrees with those of Megascops, Athene, and Aegolius in being more curved than in Asio, Strix, or Surnia. The proximal articular surfaces of the femur are broader in relationship to depth than in Athene or Aegolius, agreeing in this trait with Megascops and larger owls. No complete long bones of the species are known, and the larger size of the fossil species compared with other Megascops is evident mainly from the thicker shafts of the ulna and femur. The tarsometatarsus, described and figured by Brodkorb & Mourer-Chauviré (1984: Figure 1), is referable to Megascops based on size and narrow, slender form, though proportionately stouter and shorter than in Athene cunicularia. The tarsometatarsus is not as stout as in Asio brevipes Ford & Murray 1967 from the Upper Pliocene of Idaho nor as slender as in Athene megalospeza (Ford 1966) from the Upper Pliocene of Kansas and Idaho.

Measurements. USNM PAL 641984 (ulna), greatest width distal to cotylae, 5.2 mm. USNM PAL 769089 (femur), proximal lateromedial width from head through trochanter, 7.0 mm; width of head, 3.3 mm.

Remarks. The only previously known material of this species is the type specimen. The new material bolsters the evidence for a large extinct species of Megascops in the Irvingtonian of Maryland. It is odd that the species has no other fossil record, but perhaps some of the Pliocene fossils referred to Otus (= Megascops) are relevant to it (i.e., two bones from the Hagerman local fauna of Idaho (Ford & Murray 1967) and one from the Rexroad Formation of Kansas (Ford 1966)).