Cubaguanichthys, Schwarzhans & Aguilera, 2024

Genus Cubaguanichthys n. gen.

Type species Cubaguanichthys lanceolatus n. sp.

Etymology Named after the type formation, the Cubagua Formation of Venezuela.

Diagnosis A fossil otolith-based genus of the Gobiosomatini , Microgobius Group, Akko clade with the following combination of characters. Ventral rim straight, horizontal and posterior rim straight, vertical forming orthogonal angle; dorsal rim regularly curved, anteriorly depressed; preventral projection pointed, distinct; OL:OH = 1.2. Outer face convex, smooth. Sulcus long, narrow, with very low ostial lobe; OL:SuL= 1.8; sulcus inclination angle 16°. Subcaudal iugum short, wide, oval shaped. Ventral furrow distinct, close to ventral rim of otolith.

Discussion Cubaguanichthys has a highly distinctive otolith pattern that resembles otoliths of Akko in the straight, vertical posterior rim without indentation, the sulcus with a very low ostial lobe, and the wide, short subcaudal iugum. It differs in the more slender shape, the projecting preventral angle, and the long and narrow sulcus. Te allocation of Cubaguanichthys to the Microgobius group and Akko clade of the Gobiosomatini therefore remains tentative. It also seems possible that Cubaguanichthys represents an exotic faunal element in the tropical West Atlantic of the Late Pliocene that had emigrated from another region, but we know of no gobiid otolith morphology from outside of the American taxa that would show any significant similarity.

Species A single species, C. lanceolatus , from the Early Pliocene, Zanclean, Cubagua FM, above Cerro Negro Member, of Venezuela.