Carcharhinus obsolerus
| Carcharhinus obsolerus | ||||||||||||
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Drawing of the species from the first description |
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| Scientific name | ||||||||||||
| Carcharhinus obsolerus | ||||||||||||
| White , Kyne & Harris , 2019 |
Carcharhinus obsolerus is a species of shark in the family of Requiem or gray sharks that was only described in early 2019. Type specimens were three preserved young animals that were caught decades ago. The three young animals were found in Bangkok, Ho Chi Minh City and Baram ( Sarawak ). The range of the species is likely in the South China Sea , but could also be wider. Since therehas been no evidenceof Carcharhinus obsolerus since 1934, the species may now have become extinct.
features
The young type specimens are 34, 37 and 43.3 cm long. Since fully grown specimens are not known, their size and maximum length of the species is also unknown. The preserved juveniles are gray on the top and light on the underside. The lighter underside of the head begins at the upper edge of the eye and the outer nostrils and is visible at the edge when viewed from above. The transition of tints is sudden on the head and is gradual on the trunk and tail stalk. The gill slits are light gray and their edges are even lighter. The fins are also gray and without blackish or light markings. The first dorsal fin is gray with a lighter lower tip; the second dorsal fin is also gray with a slightly lighter outer edge. The anal fin is slightly lighter than the dorsal fins. The caudal fin is gray, the ends of the two lobes are slightly darker than the rest of the fin. The pectoral fins are gray with a light outer edge; the pelvic fins are gray and light at the base. The eyes are blackish, the nictitating membrane is light.
Carcharhinus obsolerus is likely a relatively small, slender species of shark. The head is broad and parabolic when viewed from above . The eyes are relatively large. An interdorsal ridge is missing. The front teeth in the upper jaw are triangular, serrated, and wide at the base. In the lower jaw, the front teeth are narrower and in most cases have straight tips. In both jaws, the back and side teeth are slightly curved. In the upper jaw there are 27 to 31 rows of teeth, in the lower jaw there are 26 to 29. The first dorsal fin is triangular. It begins above the first third of the pectoral fins. The second dorsal fin is slightly smaller than the anal fin and much smaller than the first. Their height is only 22 to 31% of the height of the first dorsal fin. The second dorsal fin begins well before the front end of the anal fin. The anal fin is 1.2 to 1.5 times higher than the second dorsal fin. Carcharhinus obsolerus has 114 to 120 vertebrae. Overall, Carcharhinus obsolerus is similar to the Borneo shark ( Carcharhinus borneensis ), but differs from this species in the number and morphology of the teeth and in some other morphological features.
status
The last record of the species dates back to 1934. Despite an intensive search at fish markets in the region, no more specimens have been found in the last 20 years. Since the suspected habitat of the species, the flat coasts of the South China Sea, is fished intensively and uncontrollably, it must be assumed that Carcharhinus obsolerus has meanwhile become extinct. However, it cannot be ruled out that specimens of Carcharhinus obsolerus will be found in the future . The Bornean Shark was also considered extinct for a long time before it was rediscovered in 2007.
supporting documents
- ^ A b c d William T. White, Peter M. Kyne and Mark Harris. 2019. Lost before Found: A New Species of Whaler Shark Carcharhinus obsolerus from the Western Central Pacific known only from Historic Records. PLoS ONE. 14 (1): e0209387. DOI: 10.1371 / journal.pone.0209387