Buteogallus royi, Suárez, 2020

Suárez, William, 2020, The fossil avifauna of the tar seeps Las Breas de San Felipe, Matanzas, Cuba, Zootaxa 4780 (1), pp. 1-53 : 20-22

† Buteogallus royi sp. nov.

Roy’s Hawk; Gavilán de Roy

( Figures 9 : C; 10: A–E; Table 5)

Holotype. Left tarsometatarsus, MNHNCu 75.4909. Collected in San Felipe I, C area, on May 12, 2009, by William Suárez and Stephen Díaz Franco.

Measurements (mm) of holotype. Total length: 92.9; proximal width: 13.6+; proximal depth between calcaneal ridges of hypotarsus: 5.8; proximal width at level of tubercle for tibialis anticus: 10.5; least width and depth of shaft at midpoint: 6.7–8.1; least width and depth of shaft at proximal end of metatarsal facet: 7.4–5.5; distal width: 16.1+; width and depth of trochlea metatarsi III: 4.5–6.2; width of trochlea metatarsi II: 3.4; width of trochlea metatarsi IV: 3.3 (see Table 5).

Referred material. San Felipe II: Distal third of right ulna, MNHNCu 75.4737.

Etymology. Species dedicated to the memory of Dr. Roy E. Dickerson, discoverer of Las Breas de San Felipe, and the first to report fossil bird remains in Cuban tar seeps.

Diagnosis. Species similar in size to the living Buteogallus anthracinus and B. gundlachii , but with a tarsometatarsus longer and more robust, with deep and wide anterior metatarsal groove and tubercle for tibialis anticus located more proximad.

Description. Buteogallus royi sp. nov. differs from the extinct hawks B. fragilis , B. daguetti (L. Miller, 1911) , B. terrestris ( Campbell, 1979) and B. borrasi , as well as the living species B. solitarius ( von Tschudi, 1844) , B. coronatus ( Vieillot, 1817) , B. meridionalis ( Latham, 1790) and B. urubitinga , due to its smaller size ( Table 5). The tarsometatarsus present in B. aequinoctialis ( Gmelin, 1788) is smaller. MNHNCu 75.4909 is comparable in size only to those of B. anthracinus and B. gundlachii (for size correlation of these living taxa see Olson 2006), but differs from these species by having the following combination of characters ( Fig. 9–10 A–C): shaft elongated and columnar (elongated but more gracile in B. anthracinus ; consistently shorter and more gracile in B. gundlachii ), reduced proximal end that is flaring bilaterally from a more proximal point on shaft (expanded, flaring gradually from a more distal point on shaft in B. anthracinus and B. gundlachii ), broad and deep fossa infracotylaris dorsalis (reduced and less excavated in B. anthracinus and B. gundlachii ), deep anterior metatarsal groove, very excavated and wide (less excavated and narrower in B. anthracinus and B. gundlachii ), tubercle for tibialis anticus located proximad and laterad (distad and medially located in B. anthracinus and B. gundlachii ), poorly developed internal metatarsal border (more developed and less flattened in B. anthracinus and B. gundlachii ), trochlea metatarsi II more projected mediodistad (less projected in B. gundlachii ; moderately projected in B. anthracinus ), inner calcaneal ridge of the hypotarsus with base short, only slightly extended distally, and truncated by the medial proximal foramen (similar in some specimens of B. anthracinus ; usually more distally extended in B. gundlachii ), deep posterior metatarsal groove (less deep in B. anthracinus and B. gundlachii ), metatarsal facet less expanded mediad (more medially expanded in B. anthracinus and B. gundlachii ), and well developed crista plantaris lateralis (less developed in B. anthracinus and B. gundlachii ).

Comments. The Roy’s Hawk, as the other extinct Buteogallus species present in this deposit, was a larger bird when compare with B. gundlachii , the only living species of the genus in Cuba ( Wiley & Garrido 2005), which is common in mangroves, coastal swamps of the main island, Isla de la Juventud, and keys ( Garrido & Kirkconnell 2011:79). The tarsometatarsus of B. royi sp. nov. is very different from that of B. anthracinus and B. gundlachii , being more similar to B. fragilis in some of its characters (see comparisons and description above; Fig. 9C ). The latter species (and the new Cuban taxon described herein), is not referable to genera Buteo Lacépède , Rupornis Kaup , Parabuteo Ridgway , Geranoaetus , or Spizaetus Vieillot either, being similar in most of the characters to Buteogallus , in which it has been accommodated by Howard (1932), and where I maintain both species. The distal fragment of ulna ( Fig. 10 D–E), tentatively referred to B. royi sp. nov., is also similar in size and general characters to both B. anthracinus and B. gundlachii .

Figures

FIGURE 9. Left tarsometatarsi in anterior view (A–E). A: Buteogallus fragilis (RLB K3117); B: B. fragilis (RLB E4793); C: Buteogallus royi sp. nov. (Holotype, MNHNCu 75.4909); D: B. gundlachii (WS 01); E: B. anthracinus (UMMZ 219549). Scale = 2 cm.

FIGURE 10. Buteogallus royi sp. nov.: Left tarsometatarsus (Holotype, MNHNCu 75.4909) in anterior (A), medial (B) and posterior (C) views; right ulna (MNHNCu 75.4737) in dorsal (D) and ventral (E) views. Buteo sanfelipensis sp. nov.: Left tarsometatarsus (Holotype, MNHNCu 75.4910) in anterior (F), medial (G) and posterior (H) views. Scale = 2 cm.