Uranoscopus hoedemakersi, Schwarzhans, 2023

Uranoscopus hoedemakersi n. sp.

Figure 25p–q View Fig

Holotype SMF PO 101.258 ( Fig. 25p View Fig ), Dar bel Hamri, coquina at river level of Oued Beth, Zanclean.

Paratypes 3 specimens SMF PO 101.288 , same data as holotype .

Etymology Named in honor of Kristiaan Hoedemakers (Mortsel, Belgium) for his contribution to the knowledge of fossil otoliths.

Diagnosis OL:OH = 1.8–1.9; OH:OT = 2.45. Dorsal rim with broad middorsal expansion. Sulcus deepened, anteriorly closed, with clearly distinct ostium and cauda. Anterior and posterior tips symmetrical, moderately pointed. OL:SuL = 1.75–1.9; OsL:CaL = 1.8–2.2. Broad dorsal field with many radial furrows.

Description Robust, large otoliths up to 8.5 mm in length (holotype). Dorsal rim high, with broad mediodorsal expansion and with flat predorsal and slightly curved postdorsal regions, almost triangular in shape, somewhat irregular. Ventral rim shallower than dorsal rim, regularly curved. Anterior tip inferior, strongly projecting, rounded. Posterior tip at level with anterior tip, symmetrical in expression but slightly less projecting.

Inner face mildly convex, with short, deepened, anteriorly closed sulcus. Ostium about twice as long as cauda and slightly wider, somewhat downward inclined towards collum. Cauda terminating far from posterior tip of otolith, slightly upward shifted against ostium. Dorsal depression very wide, dorsally open, with many radial furrows. Ventral field with three transverse furrows below central part of ostium. Ventral furrow running on ventral rim of otolith except somewhat turning inwards posteriorly. Outer face flat to slightly convex, somewhat irregularly shaped.

Discussion Uransocopus hoedemakersi represents a different morphotype in the highly diverse genus Uranoscopus from the other species described here. Te otoliths of the three tropical West African species— U. albesca Regan, 1915 , U. cadenati Poll, 1959 , and U. polli Cadenat, 1951 —are known ( Schwarzhans, 2019c) and also represent different morphotypes. Otoliths of U. albesca and U. cadenati are somewhat similar in otolith shape and in the reduced sulcus morphology, but show much further separation of the sulcus from the anterior rim and a small, completely unstructured sulcus. Te closest morphotype is found in U. archionema Regan, 1921 ( Fig. 25o View Fig ), a species distributed in the southeastern Indian Ocean along East Africa from Kenya to South Africa, Madagascar, and Mauritius and Reunion ( Froese & Pauly, 2022). Otolith shape, proportions, and robustness and the wide dorsal depression with radial furrows are all shared characteristics. Uranoscopus hoedemakersi differs from U. archionema in the shorter sulcus (OL:SuL = 1.75–1.9 vs. 1.4) and the clearly structured sulcus with welldefined ostium and cauda (vs. contiguous ostium and cauda). Both species are thought to represent a vicariant species pair.