Table 5. Summary of the osteological synapomorphies for the Cyprinodontiformes and comparisons with †Kenyaichthys gen. et sp. nov. compiled from [1], [3], [48], [50], [56] and [57].

Synapomorphy (author and character number)	Cypr	†Ken
Distinct expansion of the alveolar arm of premaxilla ([3]; [48], char. 13)	+	+
Dorsal edge of mesopterygoid reduced ([48], char. 32)	+	+
Urohyal deep ([48], char. 37)	+	n.a.
Ventral process of the lateral portion of second epibranchial absent ([48], char. 55)	+	n.a.
Mesethmoid region slightly anterior to lateral ethmoid ([48], char. 70)	+	n.a.
Ventrolateral pectoral fin insertion ([3]; [48], char. 74)	+	+
First postcleithrum scale-like ([3]; [48], char. 78)	+	n.a.
Anteromedial process of pelvic girdle absent ([48], char. 84)	+	+
Caudal fin skeleton symmetrical ([3]; [48], char. 86; [50], char. 37; [55])	+	+
Caudal fin truncate or rounded ([3]; [48], char. 87; [56]; [57])	+	+
Caudal fin rays continuously arranged ([1], char. 3)	+	+
Complete ankylosis of upper hypurals and terminal centrum ([1], char. 7)	+	+
Stegural minute ([1], char. 5)	+	+
One single epural ([1], char. 1; [3]; [56])	+	+
Blade-like epural ([1], char. 2; [56])	+	?
First pleural rib on second vertebra ([3]; [48], char. 95; [56]; [57])	+	+
Preural vertebra 2, well-developed neural spine with distal tip acting in support of caudal fin rays ([1], char. 4)	+	+
Preural vertebra 2, neural spine wider than neural spines of preural vertebrae 4 and 5 ([1], char. 6)	+	P
12–16 or 20–25 radii on anterior abdominal scales ([48], char. 105)	+	?

+, present;

P, polymorphic; n.a., not applicable;?, uncertain; Cypr = Cyprinodontiformes;

†Ken = †Kenyaichthys.