Morphology data of Abralia trigonura
Identification keys
Main Ref. Burgess, L.A., 1991
Appearance refers to

Sex attributes

specialized organs
different appearance
different colors
remarks

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
Diagnosis Funnel organ: dorsal pad inverted V, limbs broad with small pointed papilla, lateral ridges low; ventral pad oval, produced anteriorly. Each arms with 9-15 hooks and a series of suckers on distal third of arm. Hooks: base triangular, tip curved. Proximal third of arm suckers on long stalks, about 20-22 teeth around margin of inner ring (6 or more broad teeth on distal margin), shelf behind inner ring proximally with notch, several rows of pegs on outer ring; distal suckers globular, small aperture. Arm suckers biserial, may appear arranged in three rows in some arms. Arm IV generally lacks globular suckers; rarely with 2 or 3 following regular sucker rows. Left arm IV of male hectocotylized; ventral semicircular lappet and smaller dorsal lappet present. Both lappets thick and tend to stay folded medially. Distal suckers absent. Tentacles long. Club not expanded. Carpal cluster oval in outline, with 3-5 smooth-ringed suckers. Manus with 2-4 ventral hooks, 6-8 dorsal suckers in 2 rows. Manal suckers on long stalks, about 30 blunt teeth on inner ring, small pegs on outer ring. Dactyl suckers quadriserial (17-20 rows), few irregular teeth on inner ring margin. A ventral flap from distal portion of carpal cluster to opposite second hook. Dorsal protective membrane extends from 1st club sucker to 1st row of dactyl suckers, much narrower anteriorly. Integumentary photophores numerous; larger white ones with dark edge and smaller, darker ones of varying sizes. Photophores most numerous on ventral side of mantle, fewer toward dorsal side, few on fin surface, 3-4 on margins of vesiculate tail, none on median ventral area. On mantle ventrally, white photophores set widely apart (antero-posterior rows), smaller dark photophores scattered around and between white ones. Ventral side of funnel with 2 broad strips (narrow median space present), short strip on each side, single white photophore in each strip. Cluster of photophores close to bridles. On head ventrally a broad band of photophores (8-10 white surrounded by smaller dark organs) extends from funnel groove area, 1st and 2nd nuchal folds, to base of arms IV. Within funnel groove 2-3 isolated organs on each side present, small triangular space in front of bridles. Semicircular row extends from near 3rd nuchal fold, spreads laterally and medially to base of arm IV. Few small light organs between semicircular row and eyelid. Arm IV photophores: a row on aboral edge; another along base of tentacular sheath (white photophores distributed regularly in these rows); third row, small ones at edge of tentacular sheath, ends at 3/4 of arm length. Arm III: one white photophore near proximal end of keel, about 6 evenly-spaced small light organs deeply embedded in base of keel; 2 or 3 small photophores on dorsal side near arm base. Arm II: one small light organ at arm base. Arm I: no light organs. Five eye light organs: 2 large oval dull pink terminal organs (posterior organ 3 times size of anterior), 3 much smaller round amber-colored organs between them (middle organ slightly larger). First and third round organs usually adjacent to end organs. Gladius, with strong rachis, pointed anteriorly. Keel rounded dorsally on anterior third of gladius length (GL), a sharp ridge posteriorly. Vane length about 70% of GL, total width about 25% of GL, margins slightly concave demarcated by rounded angle. Conus small and broadly rounded. Mandibles typical enoploteuthid with three supporting ribs on gular plate of lower mandible. Spermatophores small (7.0 mm total length), slender (0.25 mm). Spiral filament 2.1 mm long, 2-3 coils behind cap. Cement gland cylindrical, 0.9 mm long. Sperm reservoir 4 mm long. Spermatophores deposited in sac-like seminal receptacle posterior to nuchal cartilage between stellate ganglia. Pigmented round spot on middorsal line of mantle indicates presence of sac below (in freshly preserved squids only). Ink sac slender, duct with bulb-like expansion before entry into rectum.
Ease of Identification

Meristic characteristics of Abralia trigonura

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
Barbels
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
total
Vertebrae
preanal
total

Fins

Dorsal fin(s)

Attributes
Fins number
Finlets No. Dorsal   
Ventral  
Spines total
Soft-rays total
Adipose fin

Caudal fin

Attributes

Anal fin(s)

Fins number
Spines total
Soft-rays total

Paired fins

Pectoral Attributes  
spines     
soft-rays   
Pelvics Attributes  
Position    
spines     
soft-rays   
Ref. [ e.g. 3742]
Glossary [ e.g. cnidaria]
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