Varicus pliocenicus, Schwarzhans & Aguilera, 2024

Varicus pliocenicus n. sp.

Figure 35d–f View Fig

Holotype NMB P15769 View Materials ( Fig. 35d View Fig ), Zanclean , Cubagua FM, Venezuela, PPP 2568 .

Paratypes 2 specimens same data as holotype ( NMB P15770-71 View Materials ) .

Referred specimen 1 specimen Zanclean, Cubagua FM , Venezuela, PPP 3093 .

Etymology Named after the occurrence of the species in the (early) Pliocene.

Diagnosis Otolith size up to 1.9 mm in length. OL:OH = 1.2–1.3. Otolith shape parallelogram-like with pronounced preventral angle and expanded postdorsal projection. Dorsal rim regularly curved. Sulcus moderately long, relatively narrow, with pointed ostial tip and tapering caudal tip; ostial lobe rounded with colliculum not extending into lobe; OL:SuL = 1.75–1.9; sulcus inclination angle 12–15°. No subcaudal iugum. Ventral furrow regularly curved.

Description Otolith size up to 1.9 mm in length (holotype). OH:OT = 2.7–2.9. Otolith parallelogram-like in shape with pronounced preventral angle, broad and expanded postdorsal projection and obtuse, rounded predorsal and postventral angles. Dorsal rim regularly curved with broad, rounded postdorsal angle. Anterior rim short, nearly vertical to slightly inclined towards dorsal. Posterior rim slightly inclined towards ventral, with narrow concavity at level of tip of cauda. Ventral rim straight, horizontal. All rims smooth.

Inner face moderately convex in both directions. Sulcus moderately long, narrow, slightly deepened, its ostial tip pointed, caudal tip tapering, narrow; ostial lobe low with rounded expansion without extension of colliculum; sulcus inclination angle 12–15°; OL:SuL = 1.75–1.9. No subcaudal iugum. Dorsal depression indistinct; ventral furrow regularly curved, closest to ventral rim of otolith at central part. Outer face convex, usually more strongly than inner face, smooth.

Discussion Varicus pliocenicus is characterized by the parallelogram-like shape that resembles the extant V. veliguttatus ; the unusual expansion of the ostial lobe without extension of the colliculum, a feature also seen in a slightly different form in the extant V. decorum ; and the pointed ostial tip and tapering, narrow caudal tip of the sulcus. Varicus pliocenicus is thus a well-defined and easily recognized otolith of this genus. None of the 12 extant Varicus species are known from off Venezuela, but three are known off Curacao: V. decorum , V. lacerta , and V. veliguttatus . Otoliths of V. decorum ( Fig. 35a View Fig ) resemble V. pliocenicus in the unusual development of the ostial lobe but otherwise show little similarity. Otoliths of V. veliguttatus resemble V. pliocenicus in otolith proportions and the pointed ostial tip of the sulcus, but differ in the rounded caudal tip, the lack of the expansion of the ostial lobe, and the less strongly developed postdorsal projection. Otoliths of V. lacerta are not known.