Tyto Billberg

Suárez, William & Olson, Storrs L., 2015, Systematics and distribution of the giant fossil barn owls of the West Indies (Aves: Strigiformes: Tytonidae), Zootaxa 4020 (3), pp. 533-553 : 535

Genus Tyto Billberg

The fossil material treated here is referable to the Tytonidae and to the genus Tyto (see Figs. 2–8 ), and differs from extinct and extant genera of Strigidae in the West Indies (see Materials and methods) by the following combination of osteological characters (see also Mourer-Chauviré 1987; Arredondo & Olson 1994; Steadman & Hilgartner 1999; Pavia 2004, among others): Coracoid less voluminous at the scapular end (much less deep) without pneumatic foramina; scapular facet, coracoidal foramen, and sternal facet, proportionately smaller; glenoid facet relatively larger; procoracoid large at base. Humerus less expanded proximally in palmar and anconal views; head proportionately small and less bulbous; bicipital furrow very deep; bicipital crest poorly developed; internal tuberosity reduced; impression of brachialis anticus much deeper. Ulna with prominence for anterior articular ligament more projected; impression of brachialis anticus deeper and more distally extended; bicipital attachment reduced; internal condyle better developed, and the sulcus intercondylaris much more extended into the internal side. Carpometacarpus with a deep fossa distad to the pisiform process (forming two marked ridges at the base of the latter); metacarpal II with internal border acute (less rounded); metacarpal III longer and well extended proximad. Femur with a more vertical trochanteric ridge (less inclined internally); distal end more flared; internal and external condyles more projected anteriorly, resulting in the rotular groove being much deeper; internal condyle larger in internal view; tuberculum M. gastrocnemialis lateralis distally located; popliteal area expanded. Tibiotarsus with slender shaft; inner cnemial crest shorter, but more projected anteriorly; sulcus intercnemialis very wide; fibular crest reduced and higher on shaft; distal fusion of fibular spine long and higher (proximad); distal portion of shaft less expanded bilaterally and less compressed antero-posteriorly; internal and external condyles projecting more posteriorly. Tarsometatarsus slender and convex anteriorly at the distal end, with lateral surface expanded (deeper); intercotylar prominence placed more anteriorly in relation to the position of anterior edges of both internal and external cotylae; ossified proximal supratendinal bridge absent (see also Brodkorb 1969:113); trochlea for digit IV massive; intertrochlear notch between trochleae for digits II and III reduced.

Figures

FIGURE 2. Left coracoids in dorsal view of Tyto noeli (A – C) compared with T. cravesae, new species: A, T. noeli (Jamaica) USNM 535720; B, T. noeli (Cuba) WS 909, image reversed to facilitate comparisons; C, T. noeli (Cuba) OA 3212; D, T. cravesae (paratype) OA 832. Scale = 1 cm.

FIGURE 3. Left humeri in anconal view (A, B) and right carpometacarpi in external view (C, D) of giant species of Tyto from the West Indies: A, T. cravesae, new species (holotype) MNHNCu 75.590; B, T. noeli (large) WS 980; C, T. cravesae, new species (holotype) MNHNCu 75.590; D, T. ostologa USNM 543378, image reversed to facilitate comparisons. Scale = 1 cm.

FIGURE 4. Right femora of giant species of Tyto from the West Indies in anterior view (A – D) and internal view (E – G): A, T. noeli (large) WS 894; B, T. ostologa USNM 543283; C, T. cravesae, new species (holotype) MNHNCu 75.590; D, T. cravesae, new species (paratype, proximal segment) MNHNCu 75. 594, image reversed to facilitate comparisons; E, T. cravesae, new species (paratype, distal segment) MNHNCu 75. 594, image reversed to facilitate comparisons; F, T. ostologa USNM 543283; G, T. cravesae, new species (holotype) MNHNCu 75.590. Scale = 1 cm.

FIGURE 5. Distal ends of right femora in anterior (A, B) and posterior (C, D) views and distal ends of left tibiotarsi in anterior view (E – G) of giant species of Tyto from the West Indies: A and C, T. noeli (Barbuda, holotype of T. neddi) USNM 359240; B and D, T. noeli (Cuba) WS 894; E, T. cravesae, new species (paratype) OA 831; F, T. cravesae, new species (paratype) MNHNCu 75.593; G, T. noeli (large) WS 345. Scale = 1 cm.

FIGURE 6. Proximal ends of right tarsometatarsi in anterior view (A – D) and distal ends of left (E, F) and right (G, H) tarsometatarsi in anterior view of giant species of Tyto from Cuba. A, T. noeli (adult) WS 15, image reversed to facilitate comparisons; B, T. cravesae, new species (juvenile, paratype) MNHNCu 75.595; C, T. cravesae, new species (adult, paratype) MNHNCu 75.596; D, T. pollens (adult), OA 3215; E, T. noeli (adult) WS 18 A; F, T. noeli (juvenile) WS 916; G, T. cravesae, new species (juvenile, paratype) WS 09 I; H, T. cravesae, new species (adult, paratype) MNHNCu 75.592. Scale = 1 cm.

FIGURE 7. Right tarsometatarsi in anterior view of giant species of Tyto from the West Indies: A, T. noeli (small specimen) WS 15, image reversed to facilitate comparisons; B, T. noeli (Jamaica) USNM 615828; C, T. noeli (large specimen) WS 898 E; D, T. cravesae, new species (paratype) MNHNCu 75.596; E, T. cravesae, new species (paratype) OA 878; F, T. ostologa USNM 543276, image reversed to facilitate comparisons. Scale = 1 cm.

FIGURE 8. Right tarsometatarsi in internal view of giant species of Tyto from the West Indies: A, T. cravesae, new species (paratype) MNHNCu 75.596; B, T. ostologa USNM 543302, image reversed to facilitate comparisons. Arrows indicate characters discussed in text. Scale = 1 cm.