Caenagnathidae

The hands of oviraptorosaurs, showing basal oviraptorosaurs (A-B), Caenagnathidae (C-G) and Oviraptoridae (H-R). Colors signify diagnostic attributes of each group, with blue representing caenagnathid features (1-7), red representing oviraptorid features (8-15), green representing “ingeniine” features (16-21), light orange representing other features (22-25) not evenly distributed among taxa, and violet representing features basal to or restricted to non-caenagnathoid oviraptorosaurs (26-31). See text for clarification. A, Protarchaeopteryx robusta, based on NGMC 2127; B, Caudipteryx sp., based on IVPP V12430; C, Anzu wyliei, based on CM 78000; D, Gigantoraptor erlianensis, based on LH V0011; E, Chirostenotes pergracilis, based on CMN 2367 and RTMP 1979.20.1; F, Hagryphus giganteus, based on UMNH VP 12765; G, Elmisaurus rarus, based on ZPAL MgD-I/98; H, Wulatelong gobiensis, based on IVPP V18409; I, Oviraptor philoceratops, based on AMNH FABR 6517; J, the Bayan Mandahu “oviraptorine,” IVPP V9608; K, the Zamyn Khondt “oviraptorid,” MPC-D 100/42; L, Citipati osmolskae, based on MPC-D 100/979; M, Conchoraptor gracilis, based on MPC-D 100/20; N, Khaan mckennai, based on MPC-D 100/1127; O, Machairasaurus leptonychus, based on IVPP V15979; P, Nemegtomaia barsboldi, based on MPC-D 107/15 and 107/16; Q, “Ingenia“ yanshini, based on MPC-D 100/30; R, Heyuannia huangi, based on HYMV1-2.

Leptorhynchos, a small caenagnathid from the Campanian of Western North America. Original work in pencil and charcoal by Nick Longrich. Additional digital editing in Adobe Photoshop by Nick Longrich.

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.