Chiloscyllium serralheiroi, Hovestadt & Da Silva, 2025

Chiloscyllium serralheiroi sp. nov.

Plate 5, Figs 43–45

Material. Three teeth.

Type Material. Holotype NHMW 2025 View Materials /0177/0023, anterior tooth; paratype 1 NHMW 2025 View Materials /0177/0024; anterior tooth; paratype 2 NHMW 2025 View Materials /0177/0025, lateral tooth.

Etymology: Named after António Romão Serralheiro (1927–2021), Portuguese geologist at the Geology Department of the Faculty of Sciences of the University of Lisbon, Portugal. He was the author of one of the very first extensive works on Portuguese Miocene sharks and rays ( Serralheiro 1954).

Locus typicus: Leixão dos Alhos site ( Fig. 1 View FIGURE 1 ), near de locality of Oura, Albufeira municipality, Algarve, southern Portugal.

Stratum typicum: Cacela Fábrica Member of the Cacela Formation outcropping along the coast of Albufeira, western Algarve, basal fine micaceous sandstone, “Bed 3” in Cachão et al. (2009: fig. 2). Upper Miocene, Tortonian.

Diagnosis. Gradient monognathic heterodont. High anterior tooth lacking any ornamentation, mesial and distal cusplet absent. Teeth up to 2.5 mm wide, anterior teeth higher than wide. Main cusp triangular, elongate and lingually directed. Principal cusp of lateral and posterior teeth inclined towards commissure. Basal edge of the apron convex and strongly overhanging the root. Root hemiaulacorhizid and heart-shaped with wide mediocentral foramen.

Description. Holotype: The anterior tooth is up to 2.2 mm wide and 2.5 mm high. The tooth possesses a large crown which is strongly lingually directed at an angle of 35° ( Pl. 5, fig. 43a). The principal cusp is triangularly shaped with concave cutting edges and a broad apron at the base that overhangs the crown-root junction. ( Pl. 5, figs 43a–c). The labial surface is slightly convex. The lingual surface is strongly concave ending in a well-developed uvula ( Pl. 5, fig. 43d). Cusplets are absent. The incomplete hemiaulacorhizid root has a large medio-central foramen. Paratype 1: The lateral tooth ( Pl. 5, figs 44a, b) has a less labiolingually developed crown that is inclined distally. The crown base is mesiodistally rounded (convex) and overhangs the crown-root junction. Cusplets are absent. The root is hemiaulacorhizid with a central foramen. Paratype 2: This lateral tooth ( Pl. 5, figs 45a–c) is more or less similar to Paratype 1 but of a more lateral position. This results in a more inclined principal cusp.

Discussion. The following species are known to belong to the genus Chiloscyllium : C. broennimanni Casier, 1958 ; C. gaemersi Müller, 1989 ; C. greeni (Cappetta, 1973) ; C. humboldtii Reuss, 1845 ; C. meraense Noubhani & Cappetta, 1997 ; C. meretiae Werner, 1989 ; C. minutum ( Daimeries, 1888) ; C. missouriensis Case, 1979 ; C. salvani Noubhani & Cappetta, 1997 ; C. frequens Guinot, Underwood, Cappetta, & Ward, 2013 , and C. vulloi Guinot, Underwood, Cappetta ,. & Ward, 2013. Overall, the genus ranges from the lower Turonian (Cretaceous) to Ypresian (Eocene), unknown from Miocene deposits. The only described and illustrated species from the Miocene is C. fossilis Probst, 1879 , however, it but was reassigned to Carcharhinus fossilis by Cappetta (2006).

The teeth of Chiloscyllium serralheiroi sp. nov. can be distinguished from those of Chiloscyllium broennimanni Casier, 1958 by the more triangularly shaped principal cusp with convex mesial and distal cutting edges, that are concave in Chiloscyllium broennimanni .

Chiloscyllium minutum ( Daimeries, 1888) has a significantly lower principal cusp, lacking cusplets in anterior teeth; lateral teeth possess a mesial cusplet that is absent in Chiloscyllium serralheiroi sp. nov.

Chiloscyllium gaemersi Müller, 1989 anterior tooth is similar to that of C. serralheiroi sp. nov. by the absence of mesial and distal cusplets but is significantly lower. Lateral teeth are stronger inclined distally in C. serralheiroi sp. nov. and tend to develop a distal cusplet.

Chiloscyllium greeni (Cappetta, 1973) has an anterior tooth possessing mesial and distal cusplets that are absent in Chiloscyllium serralheiroi .

Chiloscyllium humboldtii Reuss, 1845 has a significantly lower anterior tooth and the presence of a mesial and distal cusplet that are absent in C. serralheiroi sp. nov.

Chiloscyllium meraense Noubhani & Cappetta, 1997 has an anterior tooth with a low principal cusp having mesial and distal cusplets and concave mesial and distal cutting edges that is high without cusplets and convex mesial and distal cutting edges in C. serralheiroi sp. nov.

Chiloscyllium meretiae Werner, 1989 has an anterior tooth with a low principal cusp and mesial and distal cusplets that is high without cusplets in C. serralheiroi sp. nov.

Chiloscyllium missouriensis Case, 1979 has an anterior tooth with a principal cusp that has concave cutting edges and a labial central apron that is convex and a convex crown base without apron in C. serralheiroi sp. nov.

Chiloscyllium salvani Noubhani & Cappetta, 1997 has anterior teeth with a low principal cusp with mesial and distal cusplets as well as concave mesial and distal cutting edges that is high without cusplets and convex mesial and distal cutting edges in C. serralheiroi sp. nov.

Chiloscyllium frequens Guinot, Underwood, Cappetta & Ward, 2013 has a principal cusp with concave mesial and distal cutting edges that are convex in Chiloscyllium serralheiroi . Principal cusp also is much narrower than in C. serralheiroi sp. nov.

Chiloscyllium vulloi Guinot, Underwood, Cappetta & Ward, 2013 has a principal cusp with concave mesial and distal cutting edges that are convex in C. serralheiroi sp. nov. Principal cusp is much lower than in C. serralheiroi sp. nov. and has mesial and distal cusplets present that are absent is in the new species.

Palaeoecology: Today, Chiloscyllium View in CoL sharks are small—usually less than 1 m long—elongated, slender demersal animals commonly found on sandy and muddy bottoms of coastal waters, bays and inlets, and rocky and coral reef habitats at depths ranging from a few metres to about - 100 m. They are found in tropical waters of the Indian Ocean, The Persian Gulf, India, Madagascar, Sri Lanka, etc. Also, in the central Indo-Pacific and northern Australia ( Ebert et al., 2021). In the Tortonian of southwestern Iberia, C. serralheiroi sp. nov. inhabited subtropical to probably tropical neritic waters with an estimated depth of around 20 to 30 m over sandy bottoms.

Distribution: Miocene Eastern Atlantic, southwestern Iberian coast; Algarve Basin ( Portugal), Tortonian (this paper).