Morphology Data of Grasseichthys gabonensis
Identification keys
Main Ref. Schelly, R.C., 2007
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 more or less normal
Type of mouth/snout more or less normal
Position of mouth terminal
Type of scales scales absent

Diagnosis: very small and larval in appearance; body elongate, laterally compressed, shallow (body depth 17.9-20.0% SL in females and 15.2-17.9% SL in males); scaleless; head small (head length 18.0-22.7% SL), with small, terminal mouth and large eyes; teeth absent; interorbital distance narrow (11.9-12.9% HL); gill opening short and located above pectoral fin; pectoral fins positioned ventrally and often splayed out from the body in preserved specimens; caudal peduncle long, with keels of transparent tissue, apparently anterior extensions of caudal fin membrane, reaching forward on both dorsal and ventral edge (ventral extension is more developed); caudal fin forked, with 16 rays, including an unbranched ray on dorsal and ventral edge; fin spines lacking; 2 branchiostegal rays; body semi-translucent, with myomeres clearly visible; lateral line absent; epibranchial organ reduced or absent (Ref. 81636).

Description: dorsal fin slightly in front of anal fin (Ref. 91379). Ref. 89095 reports only 6 dorsal and anal soft rays, 4-5 pectoral fin rays and 6 pelvic fin rays (Ref. 89095). Details on osteology of skull and anterior vertebrae with associated structures in Ref. 89095 and 91379; details on hypural complex in Ref. 91379.

Coloration: base body colouration of preserved specimens yellowish; skin transparent, with scattered melanophores on body, especially along dorsal and ventral surfaces; melanophores slightly clustered into an indistinct line running along the middle of the abdomen; a distinct, dark mid-lateral line of melanophores runs the full length of the flank, bisecting the angles formed by the myomeres; melanophores also occur along the rays of all fins and in a large, dark, diamond-shaped spot at the base of the caudal fin (Ref. 81636).

Ease of Identification

Meristic characteristics of Grasseichthys gabonensis

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
total 35 - 36


Dorsal fin(s)

Attributes no striking attributes
Fins number 1
Finlets No. Dorsal   0
Ventral  0
Spines total 0
Soft-rays total 7 - 8
Adipose fin

Caudal fin

Attributes forked; more or less normal

Anal fin(s)

Fins number 1
Spines total 0
Soft-rays total 9 - 10

Paired fins

Pectoral Attributes  more or less normal
Spines     0
Soft-rays   7 - 8
Pelvics Attributes  more or less normal
Position    abdominal  before origin of D1
Spines     0
Soft-rays   6
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Bailly, Nicolas
Modified by Musschoot, Tobias
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cfm script by eagbayani, 17.10.00, php script by rolavides, 13/03/08 ,  last modified by sortiz, 06.27.17