Lost shark (Carcharhinus obsoletus)
Source-cited species reference: taxonomy from WoRMS, biology from FishBase, conservation from IUCN Red List, description from Wikipedia.
The lost shark (Carcharhinus obsoletus), previously known as the false smalltail shark, is a possibly extinct species of requiem shark (family Carcharhinidae). It is known only from the Western Central Pacific Ocean, in the southern South China Sea.
- Scientific name
- Carcharhinus obsoletus
- Authority
- White, Kyne & Harris, 2019
- Family
- Carcharhinidae
- Order
- Carcharhiniformes
- Habitat zone
- demersal
- Iucn red list
- Critically Endangered
Classification (WoRMS)
Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Elasmobranchii · Order: Carcharhiniformes · Family: Carcharhinidae · Genus: Carcharhinus.
Accepted name: Carcharhinus obsoletus · Authority: White, Kyne & Harris, 2019 · Taxonomic status: accepted · AphiaID: 1523902.
Synonyms and superseded combinations recorded for this taxon: Carcharhinus obsolerus White, Kyne & Harris, 2019.
Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=1523902 (CC BY 4.0). Accessed 2026-09-23.
Biology and life history (FishBase)
Measured values published by FishBase for Carcharhinus obsoletus. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.
Habitat zone: demersal · Body shape: elongated · Vulnerability index: 33.3 of 100 · Aquarium trade: never/rarely.
FishBase notes: 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).
Source: FishBase species summary (SpecCode 69201) — https://www.fishbase.se/summary/Carcharhinus-obsoletus.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.
Conservation status (IUCN Red List)
The IUCN Red List assesses Carcharhinus obsoletus White, Kyne & Harris, 2019 as Critically Endangered (code CR). No trend, population estimate or threat analysis is given here, because none is available from this source without the Red List API; follow the source link for the full assessment, including its date.
Source: IUCN Red List of Threatened Species (taxon 115696622) — https://www.iucnredlist.org/species/115696622/0; GBIF IUCN Red List category endpoint (taxonKey 10871057) — https://api.gbif.org/v1/species/10871057/iucnRedListCategory. Accessed 2026-09-23.
Description and natural history (Wikipedia)
Only three specimens of this species are known, found in Borneo, Vietnam, and Thailand, all of which are over 80 years old. The specimens were originally tentatively assigned as belonging to the smalltail shark (C. porosus), but a number of subtle morphometric differences revealed that they belonged to a new Carcharinus species, referred to as Carcharinus sp. A. It differs from other Carcharinus species by the relative position of the second dorsal and anal fins, as well as its low vertebral count.
As no individuals have been identified for over 80 years, C. obsoletus may be extinct. Like other members of the C. porosus subgroup, C. obsoletus likely had limited fecundity and lived in shallow waters that are easily accessed by fishermen, both of which put it at heavy risk of extinction from overfishing. However, the rediscovery of the Borneo shark (C. borneensis) in 2004 after a long period of no sightings has kept hopes for its possible survival. But in 2020, the IUCN Red List declared the lost shark to be Critically Endangered or Possibly Extinct.
Source: Wikipedia: Lost shark — https://en.wikipedia.org/wiki/Lost_shark (CC BY-SA 4.0). Accessed 2026-09-23.
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