Morphology Data of Jenynsia onca
Identification keys
Main Ref. Lucinda, P.H.F., R.E. Reis and R. Quevedo, 2002
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 more or less straight
Type of eyes
Type of mouth/snout
Position of mouth terminal
Type of scales

Having a large dorsal convex expansion at subdistal segments of right half of sixth anal-fin ray of adult males; distinct ovoid to circular dark spots confined to ventral half of flank posterior to pelvic fins; spots gradually more circular towards midventral line; predorsal scales 13-14; series of dashes or spots on body arranged in 6-8 irregular horizontal lines, consistent midlateral pattern absent; no swelling between the urogenital opening and anterior base of anal fin in females; no distinct dark rounded spot on the dorsal pectoral-fin base (Ref. 42933).

Ease of Identification

Meristic characteristics of Jenynsia onca

Lateral Lines Interrupted: No
Scales on lateral line
Pored lateral line scales
Scales in lateral series 25 - 31
Scale rows above lateral line
Scale rows below lateral line
Scales around caudal peduncle 15 - 16
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
total 9 - 9
total 30 - 30


Dorsal fin(s)

Fins number 1
Finlets No. Dorsal   
Spines total
Soft-rays total 6 - 9
Adipose fin

Caudal fin

Attributes more or less truncate; more or less normal

Anal fin(s)

Fins number
Spines total
Soft-rays total 10 - 10

Paired fins

Pectoral Attributes  
Soft-rays   14 - 16
Pelvics Attributes  
Soft-rays   5 - 7
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Torres, Armi G.
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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