Carcharhinus obsoletus White, Kyne & Harris, 2019
Lost shark
Carcharhinus obsoletus
photo by White et al., 2019

Family:  Carcharhinidae (Requiem sharks)
Max. size:  43.3 cm TL (female)
Environment:  demersal; marine
Distribution:  Western Pacific: collection records Gulf of Thailand, Vietnam and Malaysia (Borneo). Distribution is actually uncertain, with Baram in Sarawak (Malaysia) likely an accurate collection locality.
Diagnosis:  Vertebrae: 117-120. This small species is characterized by the following characters: a slender body and tail; no interdorsal ridge; in dorsal view head parabolic and is relatively wide, interorbital space 11.2-12.0% TL; eyes relatively large, its length 2.4-2.9% TL, 10.0-15.1 times in head length; row of enlarged hyomandibular pores alongside each mouth corner absent; upper anterior teeth broadly triangular and serrated, with large and coarse (non-lobate) serrations basally; lower anterior teeth with narrower, mostly straight cusps; the cusps of upper and lower anterolateral teeth with apical margin slightly recurved; lateral cusplets absent; total tooth row counts 27-31/26-29; posterior edge of mandibular plate with an elongate and crescentic indentation; second dorsal-fin origin well posterior of anal-fin origin, about opposite anal-fin midbase, while second dorsal-fin origin to anal-fin origin 1.3-2.5% TL, 0.3-0.6 times second dorsal-fin base; first dorsal-fin triangular, non-falcate, origin about opposite first third of pectoral-fin inner margin length, free rear tip just anterior to pelvic-fin origins, length 1.7-1.9 times height, inner margin 1.9-2.5 in base; second dorsal fin is much smaller than first, slightly smaller than anal fin, base 1.4-2.0 times height, height 22-31% of first dorsal-fin height; anal fin height 1.2-1.5 times second dorsal height, base 1.1-1.2 times second dorsal-fin base; total vertebral counts 117-120, monospondylous precaudal 36-40, diplospondylous precaudal 18-19, diplospondylous caudal 56-66, precaudal 54-58; absence of distinct black markings on fins (Ref. 119369).
Biology:  Maximum length (43.3 cm TL) is that of a juvenile female; size at birth likely close to 34.0 cm TL, since late-term embryo was fully developed and a 37.0 cm TL juvenile had a faint umbilical sca (Ref. 119369).
IUCN Red List Status: Critically Endangered (CR); Date assessed: 12 September 2020 (A2d; D) Ref. (126983)
Threat to humans:  harmless

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