A new record of the rare Bigeye Sand Tiger shark Odontaspis noronhai Maul, 1955 (Lamniformes: Odontaspididae) from the northwestern Pacific, with notes on dentition

Abstract

In the Pacific Ocean, the rare Bigeye Sand Tiger shark Odontaspis noronhai has only been recorded twice, once from its central and once from its eastern part. Here we report the first record of this species from the northwestern Pacific. This specimen measuring 312 cm total length (TL) was captured off northeastern Taiwan (25°25’N, 124°10’E) from a depth of 100 m (in waters over 2100 m deep) in mid-December 2019, and was retrieved on 27 December 2019 when landed in port. Photo of the fresh specimen along with morphometric and meristic data and DNA information are provided herein. Dentition of the specimen is different from all other specimens by having two cusplets on at least one side of cusps on most of the teeth (vs. only one cusplet per side), and lower total tooth count (29/29 vs. 34–38/37–46). This record documents an extended distribution (about 7864 km westward from the central Pacific Ocean), and provides strong evidence for the wide distribution and mesopelagic characteristic of this poorly known species.

Fossil marine vertebrates (Chondrichthyes, Actinopterygii, Reptilia) from the Upper Cretaceous of Akkermanovka (Orenburg Oblast, Southern Urals, Russia)

“…The number of cusplets was also recognized as a useful character to distinguish between the extant lamniform species Odontaspis ferox ( Risso, 1810 ) (2–3 pairs) and O. noronhai ( Maul, 1955 ) (1 pair) ( Humphreys et al, 1989 ; Pollerspöck and Straube, 2020 ). However, certain fossil odontaspidids appear to exhibit a variable number of lateral cusplets, e.g., Odontaspis winkleri Leriche, 1905 ( Maisch IV et al, 2020 ; Kovalchuk et al, 2023 ; Popov and Lopyrev, 2023 ) and even among extant Odontaspis species, there is at least one report of a divergent tooth pattern ( Ng et al, 2022 ). Therefore, we cannot completely rule out the possibility that these two species are conspecific.…”

Reply to Soldo, A.; Lipej, L. Comment on “Balàka et al. Updated Checklist of Chondrichthyan Species in Croatia (Central Mediterranean Sea). Biology 2023, 12, 952”

“…However, the variability in this trait is possibly best demonstrated by a recent observation of a specimen of Odontaspis noronhai (Maul, 1955) from the northwestern Pacific [ 24 ]; while the number of lateral cusplets is also regarded an useful distinguishing feature between O. ferox (two pairs) and O. noronhai (one pair), 44 out of 58 teeth in this specimen exhibited two pairs of cusplets, while the remaining teeth exhibited one pair of cusplets, demonstrating that both conditions can occur within the same individual. The identity of this species was confirmed by molecular data [ 24 ]. These examples are not meant to reflect our skepticism about the taxonomic significance of teeth, but merely to illustrate that these morphological structures exhibit the same variability as other morphological characters.…”

“…According to Lipej et al [12], the number of lateral cusplets is the main dental feature to distinguish between C. taurus (one pair of dental cusplets) and O. ferox (two pairs of dental cusplets) [12]. However, the variability in this trait is possibly best demonstrated by a recent observation of a specimen of Odontaspis noronhai (Maul, 1955) from the northwestern Pacific [24]; while the number of lateral cusplets is also regarded an useful distinguishing feature between O. ferox (two pairs) and O. noronhai (one pair), 44 out of 58 teeth in this specimen exhibited two pairs of cusplets, while the remaining teeth exhibited one pair of cusplets, demonstrating that both conditions can occur within the same individual. The identity of this species was confirmed by molecular data [24].…”