A New Species of Owl from the Pleistocene of Rancho La Brea, California

Abstract

Upon a recent examination of the owl bones in the Los Angeles Museum collections from Rancho La Brea, certain unusual specimens came to the writer's attention. All are of a size easily to be confused with slender bones of Bubo virginianus and, in fact, were found among the elements which had been so assigned in the first general survey of the collection. The specimens may be separated from those of the Horned Owl, however, on the basis of the same characters which distinguish members of the genus Strix from Bubo. Comparisons were made also with Scotiaptex, Nyctea and Asio of North America and Pulsatrix, Rhinoptynx and Ciccaba from the south.' The fossil, however, most closely accords with Strix, though it is larger than either North American species of that genus. Furthermore, from such information as can be gained from the literature on the subject, and from Dr. Wetmore who has kindly measured Strix rufipes for the writer, it is apparently larger than any other species of that genus or of the genus Ciccaba, which resembles Strix in many characters. Nine of the principal skeletal elements have been identified and are fairly well represented, the number of available specimens totalling fifty-six. With regard to the pelvis, the variation within the genus Strix and the similarities between Strix and Bubo in general characters make difficult a separation of the pelves of these two genera; this fact coupled with the somewhat fragmentary condition of the La Brea specimens has made it impossible to identify this element of the fossil form. This is the case also with the ulna. No furcula, cranium, or lower mandible of the fossil species is available; these elements are but poorly represented and the few specimens of large owl which occur in the collection appear to belong to Bubo. No attempt has been made to identify the radius, vertebrae, ribs or phalanges. In describing the species, a tarsometatarsus has been selected as the type because of completeness of the specimen and the diagnostic features of the element. The other available elements are discussed as referred material. The photographs of the type specimen were made by Mr. H. Wm. Menke.