Hexanchus griseus ( Bonnaterre, 1788 )

Hexanchus griseus ( Bonnaterre, 1788) View in CoL

Plate 6, Figs 9a, b

* Squalus griseus Bonnaterre, 1788: 9 .

Hexanchus ( Notidanus) primigenius (Agassiz) — Zbyszewski & Almeida 1950: 315, pl. 1, figs 4, 5.

Hexanchus gigas (Sismonda) — Serralheiro 1954: 41, pl. 1, figs 4–6.

Hexanchus primigenius (Agassiz) — Serralheiro 1954: 42, pl. 1, fig. 7.

Hexanchus sp. — Serralheiro 1954: 42, pl. 1, fig. 8.

Hexanchus cf. griseus View in CoL (Bonnaterre, 1780 [ sic])— Antunes & Jonet 1970: 130, pl. 4, figs 1–3.

Hexanchus griseus ( Bonnaterre, 1788) View in CoL — Herman et al. 1974: 19, pl. 1 fig. 1.

Hexanchus griseus (Agassiz) View in CoL [ sic]— Jonet et al. 1975: 201, pl. 1, fig. 17.

Hexanchus griseus (Bonnaterre, 1780) View in CoL [ sic]— Jonet 1978: 25, pl. 1, fig. 1.

Hexanchus griseus ( Bonnaterre, 1788) View in CoL — Landini 1977: 92, fig. 3, pl. 1, figs 1–9.

Hexanchus griseus ( Bonnaterre, 1788) View in CoL — Cappetta 2012: 93.

Material. One isolated tooth. NHMW 2025/0177/0036 (1).

Description. The single upper parasymphyseal tooth (Pl. 6, figs 9a, b) possesses a relative high principal cusp, that is approximately three times as high as its base width, slightly restricted near the base with a mesial cusplet and three poorly developed distal cusplets that gradually diminish in size. The anaulacorhizid root has no root lobes, characteristic for this type of root. The lingual surface is smooth, while the labial surface has a transverse ridge at one third from the base.

Discussion. The extant successor is known from epipelagic to bathypelagic zones, from 200 to - 1100m ( Ebert et al., 2016).

Distribution. Upper Miocene: Southern Italy. Miocene: Japan. Pliocene: North Carolina, Italy, southern Spain, Peru, South America. According to Capetta (1987), H. griseus , probably, had the same distribution as Hexanchus gigas .

Distribution in Portugal. Middle Miocene: (Langhian) Lower Tagus Basin ( Antunes & Jonet 1970). Upper Miocene: (Tortonian) Lower Tagus Basin ( Serralheiro 1954; Antunes & Jonet 1970); Algarve Basin, Cacela Fm. (this paper).