Morphology Data of Rhinobatos nudidorsalis
Identification keys
Main Ref. Last, P.R., L.J.V. Compagno and K. Nakaya, 2004
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance
Different colors

Descriptive characteristics of juvenile and adult

Striking features
Body shape lateral elongated
Cross section
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth
Type of scales placoid scales

This species is distinguished by the following characters: no thorns on upper surface of the disc, with tail and unpaired fins almost entirely naked; a small, elongate to oval-shaped denticle patch across a naked upper caudal peduncle and upper caudal-fin lobe; a wedge-shaped disc; moderately large orbit, exceeding 4% total length (TL); oblique nostrils, length 1.7 times internarial distance; anterior nasal flaps penetrating well into internarial space, but not almost united; posterior nasal flaps broad; ridges of rostral cartilages well separated dorsally and almost parallel; prebranchial sensory pore patch narrow, extending to first gill slit; postscapular sensory canal long with lateral pores, not grooved, extending almost to pectoral-fin insertions; low dorsal fins; pelvic-fin inner margin distinctly longer than its base; interdorsal distance less than 2.5 times first dorsal-fin base; 2 spiracular folds, outer is much larger than the inner one; caudal fin small with dorsal margin about 1.8 times preventral margin; 172 total vertebral centra; dorsal disc plain colored (Ref. 55722).

Ease of Identification

Meristic characteristics of Rhinobatos nudidorsalis

Lateral Lines Interrupted: No
Scales on lateral line
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line
Scale rows below lateral line
Scales around caudal peduncle
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb


Dorsal fin(s)

Fins number
Finlets No. Dorsal   
Spines total
Soft-rays total
Adipose fin

Caudal fin


Anal fin(s)

Fins number
Spines total
Soft-rays total

Paired fins

Pectoral Attributes  
Pelvics Attributes  
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
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