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🌊 Marine Vulnerable 🌡️ Tropical

Ranong guitarfish

Rhinobatos ranongensis Last, Séret & Naylor, 2019
Max Length
64.5 cm
Max Weight
-
Lifespan
-
Trophic Level
3.7
Depth
30–69 m
Climate
Tropical
Resilience
Low
Vulnerability
35.00/100
Typical Length
-
Depth Zone
demersal

📖 Overview

Caught individuals: males at 49.4 and 50.3 cm TL were immature and the largest female (51.1 cm TL) was most probably at late adolescent or early mature stage of development .

Scientific Name
Rhinobatos ranongensis
Authority
Last, Séret & Naylor, 2019
Habitat
Marine
Climate
Tropical
IUCN Status
VU
Max Length
64.5 cm
Depth Range
30–69 m
Trophic Level
3.7
Resilience
Low
Vulnerability
35.00/100
Salinity
30–40 ppt

🐟 Physical Description

This medium-sized species is distinguished by the following set of characters in adult male: disc is wedge-shaped and relatively narrow, its width 31-33% TL, length 1.3-1.4 times width; snout moderately elongate, its length 3.0–3.2 times interspiracular distance, 4.1-4.4 times interorbital width; orbit and spiracular openings are small, orbit diameter ~1.5 times spiracle length; nostrils weakly oblique, length 1.3-1.6 times internarial distance; mouth narrow, 5.4-6.0% TL; preoral length 6.3-6.9 times internarial distance; posterior nasal flaps are broad; spiracular folds 2, the outermost fold slightly taller than inner fold; ridges of rostral cartilage are almost parallel, converging anteriorly but not constricted medially; anterior cartilage is broadly sickle shaped, truncate posteriorly; gill slits and their interspaces are narrow, distance between fifth gill slits 3.0-3.2 times in ventral head length; prebranchial sensory pore system distinct, extending to just behind margin of first gill slit; postscapular sensory canal indistinct, deeply embedded, not forming shallow groove; thorn patches present on supraorbit and scapular region, and row along dorsal midline rudimentary, inconspicuous; denticles on dorsal fins are densest anteriorly, present but more sparse posteriorly; dorsal fins are small, height of first 5.4-6.2% TL; pelvic-fin inner margin subequal to its base length; interdorsal distance 2.9-3.3 times first dorsal-fin base; dorsal caudal margin 2.0-2.4 times the preventral margin; upper jaw with 68-82 tooth rows; snout angle 59-64°; pectoral radials 64-68; post-synarcual centra 172-176; nasal lamellae 47-48. Colouration: dorsal fins brownish anteriorly, dusky posteriorly; dorsal disc of adults largely uniformly brownish, no spots or obvious blotches; no large, black, teardrop marking on undersurface of snout Cross section: flattened.

🌀 Behaviour

Behavioural data for Ranong guitarfish is currently being reviewed.

🦐 Diet

aquatic invertebrates
small fish
algae
detritus

🥚 Reproduction

🐣 Oviparous 📦 Batch Spawner
Spawning Season
spring-summer
Spawn Location
Pelagic
Fertilization
External

🌍 Habitat & Distribution

Marine; demersal; depth range 30 - 69 m . Tropical Indian Ocean: Andaman Sea, Myanmar and western Thailand.

🌿 Ecology

Zone Preferences
🌊 Marine ⬇️ Benthic
Trophic Level
3.7±0.4

📐 Morphometrics

Length–Weight Relationship: W = 0.00302 × L3.13 (TL)
Max TL
64.5cm

🌡️ Water Parameters & Tolerance

Salinity Range
30–40ppt

🛡️ Conservation Assessment

IUCN Category
Vulnerable
Assessment Date
2020

📊 Population Risk & Fisheries

Population Resilience
Low
Minimum doubling time
Fishing Vulnerability
35.00/100
Low vulnerability
Trophic Level
3.7
Predator
Climate Zone
Tropical
Described By
Last, Séret & Naylor, 2019

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