Morphology Data of Euthynnus affinis
Identification keys
Abnormalities
Main Ref. Collette, B.B., 2001
Appearance refers to Male; Female
Bones in OsteoBase

Sex attributes

Specialized organs no special organs
Different appearance males alike females
Different colors males alike females
Remarks

Descriptive characteristics of juvenile and adult

Striking features none
Body shape lateral fusiform / normal
Cross section oval
Dorsal head profile more or less straight
Type of eyes more or less normal
Type of mouth/snout more or less normal
Position of mouth terminal
Type of scales cycloid scales
Diagnosis

This species is distinguished by the following characters: medium-sized fish with a robust, elongate and fusiform body; teeth small and conical, in a single series; total gill rakers on first gill arch 29-34; D1 XI-XIV with both dorsal fins separated by only a narrow interspace (not wider than eye), anterior spines of first fin much higher than those midway, giving fin a strongly concave outline; D2 much lower than first and followed by 8-10 finlets; anal fin followed by 6-8 finlets; pectoral fins short, never reaching interspace between dorsal fins; 2 flaps (interpelvic process) between pelvic fins; very slender caudal peduncle with a prominent lateral keel between 2 small keels at base of caudal fin; body naked except for corselet and lateral line. Colour of back dark blue with a complicated striped pattern which does not extend forward beyond middle of first dorsal fin; lower sides and belly silvery white; several characteristic dark spots between pelvic and pectoral fins (but may not always be present) (Ref. 9684, 90102).

Description: Swim bladder absent; no trace of vertebral protuberances; dorsal rays X-XV+11-15+8-10 finlets; anal rays 11-15+6-8 finlets; pectoral rays 25-29; maxilla extending posterior to middle of eye; jaw teeth are small and conical, about 25-35 on each side of lower jaw; presence of palatine teeth, none on vomer (Ref. 90102).

Ease of Identification

Meristic characteristics of Euthynnus affinis

Lateral Lines 1 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
Barbels 0
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
total 29 - 34
Vertebrae
preanal
total 39 - 39

Fins

Dorsal fin(s)

Attributes no striking attributes
Fins number 1
Finlets No. Dorsal   8 - 10
Ventral  6 - 8
Spines total 10 - 15
Soft-rays total 11 - 15
Adipose fin absent

Caudal fin

Attributes forked; more or less normal

Anal fin(s)

Fins number
Spines total 0 - 0
Soft-rays total 11 - 15

Paired fins

Pectoral Attributes  more or less normal
Spines     
Soft-rays   25 - 29
Pelvics Attributes  more or less normal
Position    thoracic  before origin of D1
Spines     
Soft-rays   
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
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