Microgobius pirabasensis, Schwarzhans & Aguilera, 2024

Microgobius pirabasensis n. sp.

Figure 28p View Fig

2014 Gobiidae , Genera and species indet. 3—Aguilera et al.: Fig. 12 View Fig /10.

Holotype MPEG- 1947-V ( Fig. 28p View Fig ), Aquitanian to Burdigalian, Pirabas FM, Brazil.

Etymology Named after the type formation, the Pirabas FM.

Diagnosis Otolith size 1.45 mm in length. OL:OH = 0.88. Otolith shape nearly rectangular; dorsal rim shallow, nearly flat and horizontal. Sulcus moderately long and narrow, with relatively low ostial lobe; OL:SuL = 1.45; sulcus inclination angle 16°. Subcaudal iugum long, narrow. Ventral furrow close to ventral rim of otolith.

Description Otolith size 1.45 mm in length (holotype). OH:OT = 4.4. Otolith shape nearly rectangular, with low, nearly flat and horizontal dorsal rim and high, rounded predorsal angle and orthogonal postdorsal projection. Anterior and posterior rims near vertical; posterior rim with very weak central concavity. Ventral rim slightly relatively straight, horizontal. Preventral and postventral angles rounded orthogonal. All rims slightly undulating.

Inner face almost flat in vertical direction and slightly bent in horizontal direction. Sulcus moderately long and narrow, with relatively low and broad ostial lobe; cauda straight, with rounded tip, not particularly deepened; sulcus inclination angle 16°; OL:SuL = 1.45. Subcaudal iugum long, narrow. Dorsal depression not discernable. Ventral furrow distinct, parallel and close to ventral rim of otolith. Outer face relatively flat and smooth.

Discussion Microgobius pirabasensis is recognized by its nearly flat, horizontal dorsal rim resulting in an almost perfect compressed rectangular otolith shape. Other characteristical features like the low ostial lobe and the ventral furrow running close and parallel to the ventral rim of the otolith are considered plesiomorphic.