Akko canoa, Schwarzhans & Aguilera, 2024

Schwarzhans, Werner W. & Aguilera, Orangel A., 2024, Otoliths of the Gobiidae from the Neogene of tropical America, Swiss Journal of Palaeontology (13) 143 (1), pp. 1-129 : 43

publication ID	https://doi.org/10.1186/s13358-023-00302-5
persistent identifier	https://treatment.plazi.org/id/492D87AA-FF81-FFCE-018C-FE36618AFE9E
treatment provided by	Felipe
scientific name	Akko canoa
status	sp. nov.

Treatment

Akko canoa n. sp.

Figure 22d–e View Fig

Holotype NMB P15556 View Materials ( Fig. 22d View Fig ), Gelasian , Canoa FM, Ecuador, PPP 3363 .

Paratypes 1 specimen, Gelasian , Canoa FM , Ecuador, NMB 19146 View Materials ( NMB P15557 View Materials ) .

Etymology After the type formation, the Canoa FM of Gelasian age in Ecuador.

Diagnosis OL:OH = 1.04–1.08. Maximal size 2.6 mm (holotype). Otolith shape nearly rectangular with postdorsal rim slightly elevated. Predorsal angle high, preventral angle orthogonal; posterior rim nearly vertical, without indentation and no marked postdorsal projection. Sulcus narrow, moderately small, with very low ostial lobe; OL:SuL = 1.8–1.9. Subcaudal iugum short, wide. Sulcus inclination angle 16–22°.

Description Otolith size up to 2.6 mm in length (holotype). OH:OT = 2.7. Dorsal rim relatively low, smooth, nearly straight, slightly ascending towards posterior. Predorsal angle high, rounded, no distinct postdorsal projection; preventral and postventral angles orthogonal. Ventral rim straight, horizontal. Anterior and posterior rims nearly vertical, posterior rim without marked indentation at its middle. All rims smooth.

Inner face flat in vertical direction, slightly bent in horizontal direction. Sulcus sole-shaped, moderately deep, narrow, inclined at 16–22°; low ostial lobe, cauda with rounded tip slightly bent upward. OL:SuL = 1.8–1.9. Subcaudal iugum short, wide. Dorsal depression indistinct, with indiscernible crista superior. Ventral furrow distinct, half-moon shaped and regularly curved at moderate distance from ventral rim of otolith. Outer face broadly convex, smooth.

Discussion Akko canoa resembles the otoliths of the two known species in shape and sulcus organization but differs in being thicker (OH:OT = 2.7 vs 3.0–3.6), the larger sulcus (OL:SuL = 1.8–1.9 vs 2.0–2.2) and the less strongly bent inner face which in the two extant species studied shows a distinct outward bent posterior region of the otolith. Akko canoa shows that a further species of the genus existed in the East Pacific other than the extant species.