Morphology Data of Gymnotus chimarrao
Identification keys
Main Ref. Cognato, D., M.M. Richer-de-Forges, J.S. Albert and W.G.R. Crampton, 2008
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance males alike females
Different colors males alike females

Descriptive characteristics of juvenile and adult

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

Distinguished from all 32 congeners except for some specimens (over 30.0 cm) of Gymnotus ardilai from the Río Magdalena drainage in northwest South America in having a pigmentation pattern in which the oblique dark-pigmented bands are faint, and difficult to distinguish from the ground color. Diagnosed from Gymnotus ardilai in having a shallower body depth (7.4-9.1 % TL [mean 8.2] vs. 11.4-13.2 [12.3]). Differs also from all species in the Gymnotus pantherinus species-group (and is placed in the Gymnotus carapo species-group) by the presence of two (vs. one) laterosensory canal pores in the preopercular-mandibular series of the dorsoposterior portion of the preopercle. Can be differentiated from all species in the Gymnotus carapo species-group that occur south of the Amazon basin except Gymnotus inaequilabiatus in having a much shallower body depth (7.4-9.1 % TL [mean 8.2] vs. 8.9-11.6 [mean 11.1] in Gymnotus bahianus, 9.8-10.3 [mean 10.1] in Gymnotus paraguensis, and 10.3-13.1 [mean 11.7] in Gymnotus sylvius). Differs further from Gymnotus inaequilabiatus in possessing a substantially narrower head (53.1-59.3 % HL [mean 57.5] vs. 65.3- 72.0 [mean 67.8]) (Ref. 75065).

Description: Pectoral fin with single large anterior unbranched rays and 13-15 branched rays (Ref. 75065).

Ease of Identification

Meristic characteristics of Gymnotus chimarrao

Lateral Lines Interrupted: No
Scales on lateral line
Pored lateral line scales 82 - 94
Scales in lateral series
Scale rows above lateral line 6 - 7
Scale rows below lateral line
Scales around caudal peduncle
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
preanal 29 - 32


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 180 - 213

Paired fins

Pectoral Attributes  
Soft-rays   14 - 16
Pelvics Attributes  
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Torres, Armi G.
Comments & Corrections
Sign our Guest Book
Back to Search
cfm script by eagbayani, 17.10.00, php script by rolavides, 13/03/08 ,  last modified by sortiz, 06.27.17