Caenagnathidae

Body mass evolution of Oviraptorosauria. Time calibrated phenograms of Log10 Body Mass (kg) versus time (Ma) for Oviraptorosauria. Blue halos represent 95% confi- dence intervals and branches indicate phylogenetic relation- ships. Each plot displays the same data, but Caenagnathidae is highlighted in green in (A) and Oviraptoridae is highlighted in red in (B) for clarity. Yellow arrows indicate nodes where important changes in body size range occur. Pie charts show ancestral estimations of biogeographic range (as in Fig. 20) for important clades of caenagnathids (A) and oviraptorids (B). Node labels from left to right in (A): Oviraptorosauria; Caenagnathidae; Anomalipes + Caenagnathinae; Caenagnathinae more derived than Apatoraptor pennatus; Anzu + Caenagnathus. Node labels from left to right in (B): Oviraptorosauria; Caenagnathoidea; Oviraptoridae; Heyuanninae (bottom); Citipatinae (top). Colours for node labels as in Fig. 20. Abbreviations: Al, Albian; Ap, Aptian; Ba, Barremian; Be, Berriasian; Ca, Campanian; Ce, Cenomanian; Co, Coniacian; Ha, Hauterivian; Ma, Maastrichtian; S, Santonian; Tu, Turonian; Va, Valanginian.

Restored skull and neck vertebra of Anzu wyliei (previously labelled as a specimen of Chirostenotes)

Restored skull and neck vertebra of Anzu wyliei (previously labelled as a specimen of Chirostenotes)

Restored skull and neck vertebra of Anzu wyliei (previously labelled as a specimen of Chirostenotes)

Anzu is a fairly large caenagnathid oviraptorosaurian dinosaur that grew to nearly 4 m in length, and weighed 200-300 kg. It was a bipedal dinosaur and was covered in feathers, with a large sloping crest atop its head. Typical of oviraptorosaurs, Anzu had a short toothless beak, an adaptation that suggests it was most likely herbivorous or possibly omnivorous.

Skeletal reconstructions of Dinosaur Park Formation caenagnathids. Skeletal reconstructions of Citipes elegans (left), Chirostenotes pergracilis (middle), and Caenagnathus collinsi (right), showing variation in skeletal representation and body size. Previously referred material is indicated in white and newly referred material is indicated in red for each taxon. Blue asterisks indicate elements that have been histologically sampled for each taxon. Citipes elegans: dentaries, metatarsal IV; Chirostenotes pergracilis: dentaries, tibia; Caenagnathus collinsi: pubis.

Caenagnathidae jaws.

Tarsometatarsi of caenagnathids from the Upper Campanian Dinosaur Park Formation, Dinosaur Provincial Park, Alberta, Canada. A. TMP 1993.036.0181 (Chirostenotes pergracilis). B. TMP 1982.016.0006 (Citipes elegans). C. ROM 781 (Citipes elegans holotype). D. TMP 1996.012.0141 (Citipes elegans). Tarsometatarsi in proximal (A1–D1), anterior (A2–D2), and posterior (A3–D3) views.

Skeletal reconstructions of Dinosaur Park Formation caenagnathids. Skeletal reconstructions of Citipes elegans (left), Chirostenotes pergracilis (middle), and Caenagnathus collinsi (right), showing variation in skeletal representation and body size. Previously referred material is indicated in white and newly referred material is indicated in red for each taxon. Blue asterisks indicate elements that have been histologically sampled for each taxon. Citipes elegans: dentaries, metatarsal IV; Chirostenotes pergracilis: dentaries, tibia; Caenagnathus collinsi: pubis.