Akko lobata, 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-0236-FEF666B5F9FE
treatment provided by	Felipe
scientific name	Akko lobata
status	sp. nov.

Treatment

Akko lobata n. sp.

Figure 22f View Fig

Holotype NMB P15558 View Materials ( Fig. 22f View Fig ), Tortonian, Yaviza FM, Pacific Panama, Darien, PPP 1566 .

Etymology From lobatus (Latin) = lobed, referring to the continuously curved anterior and dorsal rims.

Diagnosis OL:OH = 1.03. Size 1.75 mm (holotype). Anterior and dorsal rim continuously curved. Posterior rim nearly vertical, with weak and broad indentation. Sulcus narrow, moderately large, with moderate ostial lobe; OL:SuL = 1.6. Subcaudal iugum short, wide. Sulcus inclination angle 18°.

Description Otolith size up to 2.6 mm in length (holotype). OH:OT = 2.8. High-bodied otolith; anterior and dorsal rim continuously curved, postdorsal rim slightly elevated and with small indentation in front of postdorsal tip. Preventral angle rounded orthogonal; posterior rim nearly vertical, with weak and broad indentation and weak, blunt postdorsal projection. Ventral rim straight, horizontal. All rims smooth, dorsal rim slightly undulating.

Inner face nearly flat. Sulcus sole-shaped, moderately deep, long, inclined at 18°; moderate ostial lobe, cauda with rounded tip. OL:SuL = 1.6. Subcaudal iugum short, wide. Dorsal depression distinct, with poorly defined crista superior. Ventral furrow distinct, regularly curved close to ventral rim of otolith. Outer face broadly convex, smooth.

Discussion Akko lobata represents what one might envisage as a plesiomorphic otolith morphology for the genus where the sulcus is still relatively large, the ventral furrow close to the ventral rim of the otolith and the inner face is nearly flat. Tis character status is also observed in otoliths of Bollmannia and Microgobius .