Tubemouth whipray (Urogymnus lobistoma)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Chordata · Class: Elasmobranchii · Order: Myliobatiformes · Family: Dasyatidae · Genus: Urogymnus.

Accepted name: Urogymnus lobistoma · Authority: (Manjaji-Matsumoto & Last, 2006) · Taxonomic status: accepted · AphiaID: 1043414.

Synonyms and superseded combinations recorded for this taxon: Himantura lobistoma Manjaji-Matsumoto & Last, 2006.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=1043414 (CC BY 4.0). Accessed 2026-09-25.

Biology and life history (FishBase)

Measured values published by FishBase for Urogymnus lobistoma. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.

Maximum length: 49.20000076293945 cm · Habitat zone: benthopelagic · Body shape: other · Vulnerability index: 90 of 100 · Aquarium trade: never/rarely.

FishBase notes: An inshore species which I s probably with restricted distribution in brackish habitats that are associated with runoff from large rivers. Feeds on small fishes and prawns. Males mature at ca. 49 cm WD, females at ca. 70 cm WD; born at ca. 19 cm WD (Ref. 114953). Female maturity based on a pregnant female; males apparently smaller than females; full term pup 18.4 cm DW (Ref. 58327).

Source: FishBase species summary (SpecCode 63391) — https://www.fishbase.se/summary/Urogymnus-lobistoma.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-25.

Conservation status (IUCN Red List)

The IUCN Red List assesses Urogymnus lobistoma (Manjaji-Matsumoto & Last, 2006) as Endangered (code EN). 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 161546) — https://www.iucnredlist.org/species/161546/0; GBIF IUCN Red List category endpoint (taxonKey 9466978) — https://api.gbif.org/v1/species/9466978/iucnRedListCategory. Accessed 2026-09-25.

Description and natural history (Wikipedia)

The first known specimens of the tubemouth whipray were caught from the South China Sea in 1999, and initially thought to be Dasyatis microphthalmus, a species of dubious taxonomic validity. As additional specimens emerged, this ray was described as a new species by B. Mabel Manjaji-Matsumoto and Peter Last in a 2006 issue of the scientific journal Ichthyological Research. The specific epithet lobistoma is derived from the Latin lobus ("protuberance") and stoma ("mouth"), in reference to its protrusible jaws.

The type specimen is an adult male 49 cm across, collected off Bintulu in Sarawak, Malaysia. The tubemouth whipray was thought to belong to the 'uarnacoides' species complex, along with U. polylepsis, Mangrove whipray, H. hortlei, H. pastinacoides, and H. uarnacoides. It is however placed in the genus Urogymnus.

Distribution and habitat

The tubemouth whipray has only been found in the South China Sea off southern Sumatra and southwestern Borneo, to as far north as Bintulu. It is associated with the runoff from large rivers and mangrove forests, occurring in brackish water under 30 m deep over muddy bottoms.

Description

The tubemouth whipray has a diamond-shaped pectoral fin disc longer than wide, with broadly rounded outer corners. The anterior margins of the disc are strongly concave, and converge on a narrow, flattened, pointed snout. The eyes are tiny, and followed by much larger, teardrop-shaped spiracles. The nostrils are small, with a narrow, nearly rectangular flap of skin between them.

The mouth is straight and transverse, and contains no papillae (nipple-like structures). The jaws are highly protrusible, capable of forming a tube longer than the mouth width; this trait is unique within the 'uarnacoides' complex. There are 29–34 upper and 31–36 lower tooth rows; the teeth are small, conical, and blunt, and densely arranged into pavement-like surfaces. There is no sexual dimorphism in tooth shape.

The pelvic fins are short and can be rotated forwards; the males have short, stout claspers. The slender tail measures over twice the length of the disc and lacks fin folds. A single stinging spine is found on the upper surface of the tail near the base, but is frequently missing in adults. The upper surface of the disc and tail are covered by minute, blunt dermal denticles, with slightly larger plate-like denticles forming a distinct, broad band extending from before the eyes to the base of the tail; this denticle band is present at birth.

There are also 1–5 enlarged, oval denticles in a row between the "shoulders". This species is uniform grayish to light brown above, with the eyes and spiracles rimmed in white, and uniform white below. Females grow up to 1 m across, while males are smaller.

Biology and ecology

The diet of the tubemouth whipray likely consists of crustaceans and small fishes. Like other stingrays, it is aplacental viviparous with the developing embryos nourished by maternally produced histotroph ("uterine milk"). One known specimen contained a single near-term pup measuring 18 cm across. Males attain sexual maturity at under 49 cm across, and females at under 70 cm across.

Human interactions

The tubemouth whipray remains fairly common within its restricted range, particularly off Sarawak. However, its population has likely declined significantly over the past few decades due to extensive degradation of its mangrove habitat, and intense, unregulated coastal trawl and bottom longline fisheries that take it for meat. As a result, the International Union for Conservation of Nature (IUCN) has assessed this species as Endangered.

Source: Wikipedia: Tubemouth whipray — https://en.wikipedia.org/wiki/Tubemouth_whipray (CC BY-SA 4.0). Accessed 2026-09-25.