Table 2.

List of hadrosauroid supraoccipital features.

Taxon	ID	Group	Squamosal boss	Length of the exoccipital articulation surface	Ascending process	Post-temporal grooves	Posterior exposure of the ascending process
—	DMNH 2014-12-266	Lambeosaurinae	Present	Less than half of the width of the posteroventral margin of the supraoccipital	Converge posteroventrally	Present, converge posteroventrally	?
Amurosaurus riabinini40	AEHM 1/232	Lambeosaurinae	Present	?	?	?	Much less than half of the width of the posteroventral margin of the supraoccipital
Aralosaurus tuberiferus61	PIN 2229	Lambeosaurinae	Present	?	?	?	Much less than half of the width of the posteroventral margin of the supraoccipital
Charonosaurus jiayinensis69	CUST JV 1251-57	Lambeosaurinae	Present	?	?	?	Much less than half of the width of the posteroventral margin of the supraoccipital
Corythosaurus casuarius	ROM 776	Lambeosaurinae	Present	?	?	?	Much less than half of the width of the posteroventral margin of the supraoccipital
Hypacrosaurus altispinus60	AMNH 5248 CMN 2247 CMN 8675 ROM 702	Lambeosaurinae	Present	?	?	?	Much less than half of the width of the posteroventral margin of the supraoccipital
Hypacrosaurus stebingeri	AMNH 5461 USNMH 11893	Lambeosaurinae	Present	Less than half of the width of the posteroventral margin of the supraoccipital	Converge posteroventrally	Present, nearly pararell to each other	Much less than half of the width of the posteroventral margin of the supraoccipital
Jaxartosaurus aralensis78	PIN 5009/1	Lambeosaurinae	Present	?	?	?	?
Lambeosaurus lambei	CMN 1218 CMN 2759	Lambeosaurinae	Present	?	?	?	Much less than half of the width of the posteroventral margin of the supraoccipital
Olorotitan arharensi43	AEHM 2/845	Lambeosaurinae	Present	?	?	?	Much less than half of the width of the posteroventral margin of the supraoccipital
Velafrons coahuilensis79	CPC-59	Lambeosaurinae	Present	?	?	?	Much less than half of the width of the posteroventral margin of the supraoccipital
Acristavus gaglarsoni80	UMNHVP 16607	Hadrosaurinae	Absent	?	?	?	More than half as wide as the posteroventral margin of the supraoccipital
Edmontosaurus annectens	DMNH EPV. 127701 ROM 53494 ROM 59786 ROM 64623	Hadrosaurinae	Absent	Half or more than the width of the posteroventral margin of the supraoccipital	Diverge posteroventrally	Present, nearly pararell to each other	More than half as wide as the posteroventral margin of the supraoccipital
Edmontosaurus regalis35	CMN 2289	Hadrosaurinae	?	?	?	?	More than half as wide as the posteroventral margin of the supraoccipital
Gryposaurus notabilis81	AMNH FARB 5350	Hadrosaurinae	?	?	?	?	More than half as wide as the posteroventral margin of the supraoccipital
Maiasaura peeblesorum	ROM 44770 ROM 66182	Hadrosaurinae	?	?	?	?	More than half as wide as the posteroventral margin of the supraoccipital
Prosaurolophus maximus52	MOR 447-8-8-7-14	Hadrosaurinae	Absent	Half or more than the width of the posteroventral margin of the supraoccipital	Nearly parallel	Present, nearly pararell to each other	?
Bactrosaurus johnsoni56	SBDE 95E5/29	Non-hadrosaurid hadrosauroid	Present	?	Diverge posteroventrally	Absent	?
Batyrosaurus rozhdestvenskyi57	AEHM 4/1	Non-hadrosaurid hadrosauroid	Absent	?	Diverge posteroventrally	Absent	?
Eolambia caroljonesa58	CEUM 14525 CEUM 355626	Non-hadrosaurid hadrosauroid	Absent	Less than half of the width of the posteroventral margin of the supraoccipital	Diverge posteroventrally	Absent	?
Eotrachodon orientalis59	MSC 7949	Non-hadrosaurid hadrosauroid	Absent	?	Diverge posteroventrally	Absent	?
Levnesovia transoxiana82	USNM 538191	Non-hadrosaurid hadrosauroid	Present	?	?	?	?