Tyto pollens Wetmore
Creators: name: Suárez, William
name: Olson, Storrs L.
Publisher: name: Zenodo
Year: 2015
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Aves
Strigiformes
Tytonidae
Tyto
Tyto pollens

description: Tyto pollens Wetmore
Bahaman Giant Barn Owl; Lechuza Gigante de Las Bahamas (Fig. 6 D)
Tyto pollens Wetmore, 1937: 436 (type-locality “cave deposits on Great Exuma, Bahama Islands” = Little Exuma Island fide Hecht, 1955).
Tyto riveroi Arredondo, 1972b: 131, new synonymy (type-locality “Cueva de Bellamar, poco más de 1 Km. al Sur de la costa interior de la Bahía de Matanzas, Municipio de Matanzas,” Matanzas Province, Cuba).
Holotype. Left femur MCZ 2262. Collected by Vivienne Knowles in 1937.
Material examined. Hendry Cave, Royal Island, Eleuthera, Bahamas. — Coracoid: incomplete right (USNM 615825). Carpometacarpus: nearly complete right (USNM 615826). Tarsometatarsus: incomplete left (USNM 615827, lacking fragments of midshaft).
Banana Hole, New Providence, Bahamas. — Femur: proximal right (UF 41807). Tibiotarsus: distal half of left (UF 41804). Tarsometatarsus: complete left (UF 3196), incomplete left (UF 41808, lacking proximal end and trochlea for digit IV).
Cueva de Bellamar, Municipality of Matanzas, Matanzas Province, Cuba. — Tarsometatarsus: distal half of left (DPUH 1252, holotype of T. riveroi), proximal half of right (CZACC unnumbered), proximal end of right (OA 3215).
There also exist specimens from Andros, Bahamas, in the Florida Museum of Natural History (D. W. Steadman, pers. comm.).
Measurements. See Tables 1–2. Measurements of the three fragmentary tarsometatarsi of T. riveroi are here compared with those of T. pollens from the Bahamas (in parentheses, from Brodkorb 1959: 357, table 2): least width of shaft 8.4, 8.5 (8.6); width through trochleae, 21.5 (21.2); width of shaft at level of distalmost proximal foramen 13.6, 14.4 (13.7), depth through calcaneal ridge 13.9 (13.4).
Distribution. Bahamas, islands of the Great Bahama Bank; Cuba, Matanzas Province (see Fig. 1).
Remarks. This is the rarest, largest, and most robust of the Antillean barn owls, as well as being the largest representative of the genus Tyto in the New World. The species was originally named from a nearly complete femur (the holotype), an incomplete coracoid, the shaft of a major metacarpal, and the “head” of a tibiotarsus, from cave deposits thought to have come from the island Great Exuma in the Bahamas (Wetmore 1937). It was later determined that the cave was located on Little Exuma (Hecht 1955). The femur was characterized as slightly larger than that of T. ostologa of Hispaniola with the trochanteric ridge larger and more robust (Wetmore 1937: 436).
Brodkorb (1959) recorded T. pollens from deposits in Banana Hole, New Providence Island. Additional material from the same site was reported by Olson & Hilgartner (1982), who confirmed its distinction from T. ostologa and T. noeli. New material of T. pollens was collected by an expedition of the Smithsonian Institution in 1990 from Hendry Cave, Royal Island, Eleuthera, Bahamas. This consisted of a coracoid, carpometacarpus, tarsometatarsus, and few pedal phalanges. The owl remains were decidedly scarce in comparison with bones of its principal prey, the Bahaman hutia Geocapromys ingrahami (Allen). The carpometacarpus of T. pollens is much larger and more robust than in any specimen of T. ostologa available suggesting a proportionately larger wing in the former. Otherwise, the new material mentioned above provides evidence of overlap in size between T. pollens and T. ostologa (Table 1–2), but the former can be recognized by its decided robustness and other characters (see Wetmore 1937; Brodkorb 1959; Olson & Hilgartner 1982).
It is likely that T. pollens was present on all of the islands of the Great Bahama Bank inhabited by Geocapromys Chapman. There is as yet no evidence of the species from the islands of the Little Bahama Bank, where Geocapromys may not have existed until introduced by Amerindians (see Olson & Hilgartner 1982).
Arredondo (1972b) described a new species, Tyto riveroi, based on the distal half of a tarsometatarsus from a cave deposit in Matanzas Province, Cuba, that was much larger than T. noeli. For reasons discussed below, Arredondo was always under the impression that Tyto noeli, T. ostologa, and T. pollens were all of about the same size, therefore making T. riveroi distinctive by its greater size, which is not correct. We have located additional specimens from Cuba that are referable to T. riveroi. This material (topotypes) includes two proximal ends of right tarsometatarsi lacking articular surfaces (see Material examined), collected by Manuel Rivero de la Calle at the same time and place as the holotype. These fossils had never been mentioned in the literature, even though one of them was included in Arredondo’s paleontological collection. We were able to make direct comparisons of that specimen (OA 3215) with the tarsometatarsus of T. pollens. In size, T. riveroi is similar to T. pollens and there are no other distinctions to be made between them. Therefore we consider Tyto riveroi Arredondo 1972b, to be a junior subjective synonym of T. pollens Wetmore 1937. Fossils erroneously identified as T. riveroi by Salgado et al. (1992: 28, table 1) from cave deposits in Pinar del Río Province, were based on part of the type material of Bubo osvaldoi.
Brodkorb (1959:357) considered the possibility that Tyto pollens and T. ostologa were possibly differentiated only at the subspecific level but we agree with other authors (Wetmore 1922, 1937; Arredondo 1972a; Olson & Hilgartner 1984; Steadman & Hilgartner 1999) in considering them distinct at the species level, along with the other taxa recognized here. The rarity of Tyto pollens in Cuba is difficult to understand, although it could possibly be related to the much greater number of other avian predators on that island as opposed to the Bahamas.
description: Published as part of Suárez, William & Olson, Storrs L., 2015, Systematics and distribution of the giant fossil barn owls of the West Indies (Aves: Strigiformes: Tytonidae), pp. 533-553 in Zootaxa 4020 (3) on pages 539-540, DOI: 10.11646/zootaxa.4020.3.7, http://zenodo.org/record/240356