Anhima cornuta (Brisson 1760; horned screamer, aka Palamedea cornuta) skull shown belongs to Chauna torquata (Oken 1816; Southern screamer; up to 90 cm in length) Screamers are extant birds in the family Anhimae. They include the genera Chauna and Anhima . The clade lacks uncinate processes on the ribs. but has large spurs on the metacarpus. The young are precocial (able to run soon after hatching). This is a rather primitive and very vocal clade.

Large spurs arise from the distal metacarpus (as a new ossification) and from the proximal metacarpus (as the return of digit ‘0’, a digit first brought to light with the Limusaurus discovery and misinterpretation). Along with the return of digit ‘0’ we also find fused vestiges of digits 4 and 5.

Goura cristata (Pallas 1764; Stephens 1819) is the extant Western crowned pigeon, restricted to New Guinea. In the LRT it nests between Chauna and the larger pigeons, Raphus and Pezophaps. The diet is fruits and seeds. So New World vultures are giant pigeons.

Field DJ, Benito J, Chen A, Jagt JWM and Ksepka DT 2020. Late Cretaceous neornithine from Europe illuminates the origins of crown birds. Nature 579:397–401.

Linnaeus C 1758. Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio decima, reformata.

Oken L 1816. Lehrbuch der Zoologie (or Lehrbuch der Naturgeschichte 1–3. Theil. Zoologie ; 2. Abt. Fleischthiere) Jena.

Pallas PS 1764. Adumbratiunculae avium variorum praecedenti Elencho inserlarum, sed quae in Systemate Naturae Illustr. Linnaei nondum extant. Pp. 1-7 in Vosmaer 1764.

Stephens JF 1819. General Zoology, or Systematic Natural History (in English and Latin). Volume 11 Part 1. London: G. Kearsley. p. 119.

wiki/Chauna
wiki/Anhima
wiki/Goura