![]() Our finds suggest that the blacktip shark reached a circumglobal distribution in warm waters (including the then warmer-than-today Mediterranean Sea) not later than the Pliocene at the same time, they demonstrate that the continued study of the relatively well-investigated Neogene elasmobranch faunas of Italy can still result in significant novelties. limbatus as a fossil from both Europe and the Mediterranean Basin. Therefore, the Tuscan specimens described herein represent the first occurrence of C. limbatus have been reported from Neogene and Quaternary deposits of the Americas and Indo-Pacific Asia. A survey of the palaeoichthyological literature and online resources reveals that fossils of C. 5.1-4.5 Ma) marine deposits of Tuscany (central Italy). Here we report on two fossil teeth attributed to the blacktip shark Carcharhinus limbatus (Elasmobranchii: Carcharhiniformes: Carcharhinidae) from lower Pliocene (ca. , 2021b) -an observation that evokes a rather gradual transition from the preevaporitic Mediterranean assemblages of the Tortonian and Messinian (e.g., Menesini 1967Menesini, 1969Arambourg 1927 Ward & Bonavia 2001) through the Messinian Salinity Crisis (cf. 2020b) and the rays (e.g., members of the extant genera Aetobatus Blainville, 1816 and Anoxypristis White & Moy- Thomas, 1941 Collareta et al. Thus, along the Pliocene coasts of Tuscany, a largely modern carcharhine assemblage coexisted along with "Miocene survivors" among both the sharks (e.g., the extinct Pachyscylli um distans (Probst, 1879) and Megascyliorhinus mio caenicus (Antunes & Jonet, 1970) Manganelli & Spadini 2019 Collareta et al. 2021c) and other remarkable finds (e.g., Carnevale et al. 2018), descriptions of new taxa (e.g., Collareta et al. study of the relatively well-investigated Neogene elasmobranch faunas of Italy can still result in significant novelties such as new distributional records (e.g., Spadini & Manganelli 2015 Collareta et al. The genus Carcharomodus Kriwet, Mewis & Hampe, 2015, recently created to accommodate these teeth, is discussed and discarded. By the middle Zanclean, the species seems to have disappeared. ![]() Isurus subserratus probably originated in the Serravallian of the North Sea Basin and its occurrence was restricted to the Atlantic coastline of Europe and the United States. The gradual dental evolution clearly shows that the species descended from Isurus oxyrinchus Rafinesque, 1810 and is not related to the Carcharodon lineage. These four Langenboom types are also recognised in the sparse existing literature on in situ collected specimens. Lower teeth become more massive in appearance, the crenulations on the cutting edges get coarser and more irregular, and lateral cusplets disappear in all tooth positions. We observe that over time, the size increases, particularly on upper anterior teeth, together with a broadening of the crown. ![]() Based on the morphology and taphonomic condition, we identified four well defined consecutive morphotypes of Isurus subserratus teeth in the abundant Langenboom material. Owing to scarcity of these teeth outside the Netherlands, Belgium and Germany, this species is poorly known, and its generic attribution has been for a long time the subject of debate. At this locality, the crenulated teeth of the extinct mako shark Isurus subserratus (Agassiz, 1843), commonly listed in the palaeontological literature with the specific name of escheri, are exceptionally common. The locality of Langenboom (Noord-Brabant, the Netherlands), also known as Mill, is famous for the massive number of isolated shark teeth recovered between 19 by fossil collectors from dumped upper Miocene and lower Pliocene sands. ![]()
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