Table 1.

Measurements of the holotype and referred specimens of Me. efremovi and the holotype of Me. romeri. All measurements are in centimetres.

	Mesenosaurus efremovi			Mesenosaurus romeri
	OMNH 73209a	OMNH 73500	OMNH 73208	PIN 158/1a
maximum length	7.5	8	6.5	4.8
interorbital width	1.2	1.4	0.6	0.8
orbit height	2.7	2.4	1.9	?
orbit width	2.1	2.2	1.8	1.8
temporal fenestra height	?	2.0	?	?
temporal fenestra width	?	1.7	?	?

^aHolotypes.