Caloenas, G. R. GRAY, 1840

GENUS CALOENAS G.R. GRAY, 1840 View in CoL

Remarks: The genus Caloenas is represented by one extant species, the Nicobar pigeon Caloenas nicobarica ( Linnaeus, 1758) . This is a large pigeon, with spectacular plumage, that is restricted to insular parts of Southeast Asia through Indonesia and New Guinea, extending to the Solomons ( Dickinson & Remsen, 2013). The extinct species Caloenas canacorum Balouet & Olson, 1989 was described from New Caledonia based on three coracoids, part of a sternum, two scapulae and a distal humerus, which reveal a bird some 25% larger than the Nicobar pigeon ( Balouet & Olson, 1989). Steadman (1989, 2006a) referred specimens from Tonga (archaeological sites on Lifuka, Ha'ano and Ha'afeva in the Ha'apai Group) to Caloenas cf. nicobarica . In addition, there is a single specimen of a third species, Caloenas maculata ( Gmelin, 1789) , collected historically from an unknown location before 1783. This specimen is a bird 32 cm long, smaller than C. nicobarica (40 cm), and has been confirmed as a member of Caloenas based on molecular data ( Heupink et al., 2014). Tongan specimens referred to C. canacorum cannot be C. maculata , because they are of similar size to the New Caledonian bones, and thus are from a much larger taxon.

Thespecimenslistedbelowallrepresentalargepigeon distinct from Ducula , and thus differ substantially from the giant form described below in that genus. They are identified as being from a species of Caloenas because of the combination of features observed in the coracoid, tibiotarsus and tarsometatarsus ( Fig. 3). Coracoid: with the cotyla scapularis elongated laterosternally into an acute angle, and the tuberculum A ( Worthy, 2012) globose, dorsally prominent over the sulcus supracoracoideus and with a relatively narrow separation from the cotyla scapularis. Sternally, the impressio m. sternocoracoidei is pneumatic and widely separated from the medial margin by a dorsoventrally thickened (inflated) section of the corpus extending from the angulus medialis. Tibiotarsus: distal end, craniocaudal depth of condylus medialis greater than distal width; proximal attachment for retinaculum extensorium tibiotarsi (ptRET) close to condylus medialis (separation less than proximodistal length of condyle); distal attachment for retinaculum extensorium tibiotarsi (dtRET) is wider than long; the sulcus extensorius is bounded laterally by a rounded ridge (not sharp crest). Tarsometatarsus: elongate, but fossa parahypotarsalis medialis nearly reaches fossa metatarsi I; foramen vascularia proximalia both small; tuberositas m. tibialis cranialis deep set in sulcus extensorius, not prominent; anterior facies adjacent to sulcus extensorius flat to slightly convex; and trochlea metatarsi IV not deeply notched distoplantarly and ends proximad to trochlea metatarsi II.