Elasmobranchii (sharks and rays) >
Rhinopristiformes (Shovelnose rays) >
Rhinobatidae (Guitarfishes)
Etymology: Rhinobatos: Greek, rhinos = nose + Greek, batis, -idos = a ray (Raja sp.) (Ref. 45335); borneensis: Named for its type locality, Borneo..
Environment: milieu / climate zone / depth range / distribution range
Ecology
Marine; benthopelagic. Tropical; 8°N - 1°N, 108°E - 118°E (Ref. 114953)
Northwest Pacific: South China Sea, off Borneo.
Size / Weight / Age
Maturity: Lm ? range ? - 63 cm
Max length : 68.6 cm TL male/unsexed; (Ref. 108568); 90.0 cm TL (female)
Short description
Identification keys | Morphology | Morphometrics
This species is distinguished by the following characters in adults: a wedge-shaped disc, its width 29-31% TL and length 1.30-1.42 times width; snout length 2.5-3.3 times the interspiracular distance, 3.8-5.6 times the interorbital width; medium-sized orbit, 1.5-2.2 times the spiracle length; nostrils weakly oblique, length 1.5-1.7 times internarial distance; preoral length 7.4-8.1 times the internarial distance; anterior nasal flaps are penetrating slightly into internarial space but well separated at their insertion (not reaching level of inner corner of nostril); posterior nasal flaps are broad; spiracular folds 2, the outermost fold distinctly taller than inner fold; ridges of rostral cartilage almost parallel, converging slightly anteriorly but not constricted medially; anterior cartilage sickle-shaped, pointed or blunt posteriorly; distance between fifth gill slits 2.7-3.3 times in ventral head length; prebranchial sensory pore patch obvious, extending to just behind first gill slit; postscapular sensory canal apparent with exposed lateral pores, grooved; thorn patches present on supraorbit, scapular region, and dorsal midline rudimentary, not evident; in males pelvic-fin inner margin subequal to its base, shorter in females; interdorsal distance 2.5-3.3 times first dorsal-fin base; dorsal caudal margin 1.9-2.3 times preventral margin; upper jaw with ca. 90 tooth rows; post-synarcual centra 176-180; nasal lamellae 50-53; dorsal fin usually with a large, often faint, central dusky blotches; in adults dorsal disc yellowish or brownish, often with diffuse pale yellowish blotches, without white spots; young with ocellate markings (Ref. 108568).
This species is probably benthic on continental shelf. Biology of the species is poorly known, but for finding a pregnant female with 6 pups (Ref. 108568). Matures at ca. 63 cm TL (Ref. 114953).
Life cycle and mating behavior
Maturities | Reproduction | Spawnings | Egg(s) | Fecundities | Larvae
Last, P.R., B. Séret and G.J.P. Naylor, 2016. A new species of guitarfish, Rhinobatos borneensis sp. nov. with a redefinition of the family-level classification in the order Rhinopristiformes (Chondrichthyes: Batoidea). Zootaxa 4117(4):451-475. (Ref. 108568)
IUCN Red List Status (Ref. 130435)
Threat to humans
Harmless
Human uses
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Estimates based on models
Phylogenetic diversity index (Ref.
82804): PD
50 = 0.5000 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00295 (0.00151 - 0.00578), b=3.13 (2.96 - 3.30), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref.
93245).
Trophic level (Ref.
69278): 3.7 ±0.4 se; based on size and trophs of closest relatives
Resilience (Ref.
120179): Low, minimum population doubling time 4.5 - 14 years (Preliminary low fecundity).
Fishing Vulnerability (Ref.
59153): High vulnerability (56 of 100).
