Morsoravidae, Mayr & Kitchener, 2023

Mayr, Gerald & Kitchener, Andrew C., 2023, A new fossil from the London Clay documents the convergent origin of a “ mousebird-like ” tarsometatarsus in an early Eocene near-passerine bird, Acta Palaeontologica Polonica 68 (1), pp. 1-11 : 2

Family Morsoravidae nov.

LSID Zoobank: http://zoobank.org/ urn:lsid:zoobank.org:act:B81B0E09-9CC3-44E9-9FCF-BB6667A90FE0 .

Type genus: Morsoravis Bertelli, Lindow, Dyke, and Chiappe, 2010 .

Included genera: Morsoravis Bertelli, Lindow, Dyke, and Chiappe, 2010 ; Pumiliornis Mayr, 1999 ; Sororavis gen. nov.

Diagnosis.—The new taxon is characterised by (1) a high number of 21 praesacral vertebrae (not ascertainable for Sororavis gen. nov.); (2) a long and slender tibiotarsus; (3) a very large tuberositas musculi tibialis cranialis that is situated at the medial margin of the tarsometatarsus on the level of the foramina vascularia proximalia; (4) a trochlea metatarsi II of cylindrical shape that is plantarly deflected and has a marked and extensive trochlear furrow; (5) a fossa on the dorsal tarsometatarsus surface immediately proximal to the trochlea metatarsi III; (6) a trochlea metatarsi IV that exhibits a plantarly directed, wing-like flange and has a laterally slanted distal margin, which forms an angle of about 45° relative to the longitudinal axis of the tarsometatarsus (the presence of the flange is not ascertainable for Morsoravis ); (7) a very wide first phalanx of the fourth toe (not ascertainable for Sororavis gen. nov.). Characters (4) and (7) are here considered diagnostic apomorphies of the new taxon.