Morphology Data of Characidium satoi
Identification keys
Main Ref. Melo, M.R.S. and O.T. Oyakawa, 2015
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance
Different colors
Remarks Mature males can be distinguished by having hooks on the pelvic-fin rays and, in some specimens, pectoral- and dorsal-fin rays. The hooks found exclusively on the branched rays. Breeding males with distinctively darker color (vs. non-breeding males with pale ground color in head and body) and relatively thicker bodies.

Descriptive characteristics of juvenile and adult

Striking features
Body shape lateral fusiform / normal
Cross section
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth sub-terminal/inferior
Type of scales cycloid scales

Characidium satoi is distinguished externally from its congeners by having area between pelvic fin and origin of anal fin moderate to strongly convex in lateral view (vs. area between the pelvic fin and the anal-fin origin straight); and by color pattern, with females, juveniles, and non-breeding males consisting of irregular and discontinuous bars, forming dorsal blotches separated from ventral part, which is V-shaped, W-shaped, or diamond-shaped, or breeding males having less distinct patterning and an overall darker, more uniform pigmentation. It possesses one putative internal autapomorphy, the anteriormost first anal-fin radials inserted between the fifth and sixth caudal vertebrae. Additional external diagnostic characters useful for its identification include the following: isthmus scaled; lateral line complete, with 34-37 perforated scales; anal-fin origin far posterior from anus, separated by 4 to 7 scales (vs. anal-fin origin close to anus, separated from anus by 2 to 4 scales in all congeners, except in C. hasemani, C. litorale , and C. zebra ); distal tip of anal-fin rays reaching base of ventral caudal-fin ray (vs. not reaching, except in C. bahiense, C. hasemani, C. mirim, and C. zebra, and mature males of C. rachovii); and presence of hooks on the pectoral- and pelvic-fin rays in males (vs. absence, except in C. bahiense, C. bimaculatum, C. lagosantense, C. litorale, C. mirim, C. nupelia, C. stigmosum, C. xanthopterum, and C. xavante) (Ref. 104008).

Description: Dorsal-fin rays ii+9; anal-fin rays ii+6; pectoral-fin rays iii+7+i, iii+8+i, iii+8+ii, or iii+9+1; pelvic-fin rays i+7+i (Ref. 104008)..

Ease of Identification

Meristic characteristics of Characidium satoi

Lateral Lines Interrupted: No
Scales on lateral line
Pored lateral line scales 34 - 37
Scales in lateral series 34 - 37
Scale rows above lateral line 4 - 4
Scale rows below lateral line 5 - 6
Scales around caudal peduncle 12 - 14
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
preanal 18 - 18
total 34 - 34


Dorsal fin(s)

Attributes no striking attributes
Fins number 1
Finlets No. Dorsal   
Spines total
Soft-rays total 11 - 11
Adipose fin present

Caudal fin

Attributes forked

Anal fin(s)

Fins number
Spines total
Soft-rays total 8 - 8

Paired fins

Pectoral Attributes  more or less normal
Pelvics Attributes  more or less normal
Position    abdominal  behind origin of D1
Soft-rays   9 - 9
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Torres, Armi G.
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