Negaprion eurybathrodon ( Blake, 1862 )

Hovestadt, Dirk C. & Da Silva, Carlos M., 2025, A new chondrichthyan (Sharks and Rays) Fossil Assemblage from the Miocene Cacela Fm. at Albufeira (Algarve, Portugal) with two new species: Palaeoecology and Biogeography, Zootaxa 5724 (1), pp. 1-66 : 26

Negaprion eurybathrodon ( Blake, 1862)

Plate 5, Figs 11–31

* Lamna eurybathrodon Blake, 1862: 316 .

Cestracion ( Sphyrna) magnus (Cope) — Zbyszewski & Almeida 1950: 350, pl. 7, figs 149–156. Cestracion elongatus (Leriche) — Serralheiro 1954: 67, pl. 2, figs 58, 59.

Negaprion eurybathrodon ( Blake, 1862) — White 1955: 191–193, figs 1–10.

Negaprion cf. eurybathrodon ( Blake, 1862) —Antunes, & Jonet 1970: 175, pl. 13 (12 lapsus), figs 80, 81. Negaprion eurybathrodon ( Blake, 1862) — Jonet et al. 1975: 205, pl. 1, figs 3–6.

Negaprion eurybathrodon ( Blake, 1862) — Longbottom 1979: 61.

Negaprion eurybathrodon (Blake) — Antunes et al. 1981: 18, pl. 2, fig. 17, pl. 3, fig 8.

Negaprion eurybathrodon ( Blake, 1862) — Müller 1999: 51, pl. 7, figs 2–4.

Negaprion eurybathrodon ( Blake, 1862) — Purdy et al. 2001: 156, figs 57h, j.

Negaprion eurybathrodon ( Blake, 1862) — Ward & Bonavia 2001: 140.

Negaprion eurybathrodon ( Blake, 1862) — Cappetta 2012: figs 290a–d.

? Negaprion eurybathrodon ( Blake, 1862) — Laurito et al. 2014: 164, figs 2, 1–3.

Negaprion eurybathrodon ( Blake, 1862) — Carrillo-Briceño et al. 2016: 16, figs 1–7.

Material. 301 isolated teeth. NHMW 2025 /0177/0008 ( 24 specimens) .

Description. The dentition of an extant successor Negaprion acutidens ( Rüppell,1837) was illustrated by Bass et al. (1975a: 92, pl. 4) that is used to identify the fossil remains.

The upper teeth ( Pl. 5, figs 11–21) have a relatively high principal cusp, one third as high as its base width, that is constricted near its base and slightly more inclined in teeth closer toward the commissure. The mesial and distal cutting-edge extinctions often are blade like. The root is divided into two equally wide root lobes that diverge at an angle of approximately 160°. The lower teeth ( Pl. 5, figs 22–31) have a high, narrow principal cusp, four times as high as its base, constricted near its base, resulting in a mesial and distal extension that are often blade like. The principal cusp gradually inclines distally closer toward the commissure. The root is divided into equal wide root lobes that diverge at an angle of 160 to 170°.

Discussion. Assignment of this species to Negaprion is now generally accepted. Negaprion eurybathrodon is one of the best represented species in the study assemblage. It is the third most abundant in the bulk sample with 33 out of 319 specimens ( Fig. 5 ) and the second most abundant in the search sample with 268 out of 2260 specimens ( Fig. 4 ). This extinct species was widly distributed in the western and eastern North Atlantic, the Caribbean and the Mediterranean, and has been reported at least from the Upper Eocene ( e.g., Parmley et al. 2003; Maisch et al. 2015) to the Pliocene ( Brée et al. 2022).

Distribution. Miocene–Pliocene: Southern France, Portugal ( Cappetta 1987), Georgia, USA ( Weems & Edwards 2001), North Carolina and Florida, USA, Ecuador ( Müller 1999).

Distribution in Portugal. Lower Miocene: (Burdigalian) Lower Tagus Basin ( Zbyszewski & Almeida 1950; Serralheiro 1954; Antunes et al. 1981). Middle Miocene: (Langhian-Serravallian) Lower Tagus Basin ( Zbyszewski & Almeida 1950; Serralheiro 1954; Antunes & Jonet 1970); Algarve Basin, Lagos–Portimão Fm. ( Antunes et al. 1981). Upper Miocene: (Tortonian) Lower Tagus Basin ( Serralheiro 1954); Algarve Basin, Cacela Fm. (this paper).

Figures

FIGURE 4. Taxa identified in the search sample assemblage with their absolute and relative abundances within the sample. Taxa in bold, together, represent 66.9% of the assemblage. Specimens in the search sample: 2260. Total number of specimens examined (search + bulk sample): 2579.

FIGURE 5. Taxa identified in the bulk sample assemblage with their absolute and relative abundances within the sample. Out of a total of 431 chondrichthyan remains collected, 319 were identified.Taxa in bold, together, represent 55.5% of the assemblage. They are the most representative ones for palaeoecological interpretation as, presumably, they were the most abundant species in the chondrichthyan coastal fauna of this region of southwestern Iberia during the Late Miocene Tortonian. Specimens identified in the bulk sample: 319. Total number of specimens examined (search + bulk sample): 2579.