Rhizoprionodon ficheuri ( Joleaud, 1912 )

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 : 21-22

Rhizoprionodon ficheuri ( Joleaud, 1912)

Plate 4, Figs 1 –13

* Carcharias ( Physodon) ficheuri Joleaud 1912: 199 , pl. 6, figs 4–11 (not figs 1–3).

Carcharias ( Hypoprion) lusitanicu s Jonet 1966: pl. 1, figs 5, 6, pl. 4, figs 26, 27.

Physodon miocenicus Jonet 1966: 74 , pl. 3, figs 3–12.

Scoliodon dentatus Jonet 1966: 4 , figs 3–10.

Scoliodon af. taxandriae ( Leriche, 1926) — Jonet 1966: 78, pl. 4, figs 16–17.

Physodon fischeuri ( Joleaud, 1912) — Cappetta 1969: pl. 10, figs 37–51.

Physodon ficheuri ( Joleaud, 1912) — Cappetta 1970: 63, pl. 15, figs 18–27, pl. 16, figs 1–4.

Scoliodon taxandriae Leriche, 1926 [ sic]— Jonet 1978: 31, pl. 1, figs 12, 14, 24.

Rhizoprionodon ficheuri ( Joleaud, 1912) — Cappetta 2012: 301, figs 283a–e.

Rhizoprionodon ficheuri ( Joleaud, 1907 [ sic]) — Schultz 2013: 89, pl. 10, figs 9a, b ( cum syn.).

Rhizoprionodon ficheuri Joleaud, 1912 [ sic]— Fialho 2015: 38, pl. 2, fig. 4.

Rhizoprionodon ficheuri ( Joleaud, 1912) — Fialho et al. 2021: 416, figs 6g, h.

Rhizoprionodon ficheuri ( Joleaud, 1912) — Fialho 2022: 124, pl. 5, fig. D.

Material. 120 isolated teeth. NHMW 2025 /0177/0016 ( 15 specimens) .

Description. The dentition of an extant successor Rhizoprionodon acutus ( Rüppell, 1837) was illustrated by Bass et al. (1975a: 97, pl. 9) that is used to identify the fossil remains that were found. The species is a dignathic heterodont. Generally, the upper teeth ( Pl. 4, figs 1–6) can be distinguished by their rather broad-based principal cups changing from slightly inclined in anterior teeth to strongly curved and a blade-like cusplet in lateral and posterior teeth. The mesial cutting edge is slightly sigmoidal. The teeth diminish in size towards the commissure. The lower teeth ( Pl. 4, figs 7–13) possess an inclined principal cusp with a concave mesial cutting edge becoming mesiodistally wider with an upright principal cusp at further lateral positions. A distal irregularly shaped blade is present. The teeth diminish in size towards the commissure.

Discussion. Rhizoprionodon ficheuri shares many similarities with the extant R. acutus ( Rüppell, 1837) . On this topic, see also Ebersole et al. (2023), were issues with R. ficheuri specimens from the French type locality are discussed in length. However, in this work, we follow Cappetta (2012).

This species is one of the best represented species in the study assemblage. It is the fifth most abundant in the bulk sample with 24 out of 319 specimens ( Fig. 5 ) and the eighth most abundant in the search sample with 96 out of 2260 specimens ( Fig. 4 ).

Distribution. Lower–Middle Miocene: Paratethys, Austria ( Schultz 2013). Miocene: North Sea Basin, Belgium ( Cappetta 1987). Middle–Upper Miocene: Proto-Mediterranean, southern France, Italy ( Cappetta 1987).

Distribution in Portugal. Lower Miocene: Lower Tagus Basin ( Antunes et al. 1999b). Middle Miocene: (Langhian-Serravallian) Lower Tagus Basin ( Fialho 2015; Fialho et al. 2021). Upper Miocene: (Tortonian) Algarve Basin, Cacela Fm. (this paper); (Messinian) Alvalade Basin, Esbarrondadoiro Fm. ( Antunes et al. 1999a; Antunes & Balbino 2004).

Figures

FIGURE 1. Location of thestudy site, Leixão dosAlhos,Oura region,Albufeira municipality,southern Portugal, thegeographical coordinates: 37° 4'58.60"N, 8°14'0.39"W. H—Location of the Auramar Beach Resort Hotel.

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.