Morphology Data of Thryssa baelama
Identification keys
Main Ref. Whitehead, P.J.P., G.J. Nelson and T. Wongratana, 1988
Appearance refers to
Bones in OsteoBase

Sex attributes

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

Descriptive characteristics of juvenile and adult

Striking features none
Body shape lateral fusiform / normal
Cross section compressed
Dorsal head profile clearly convex
Type of eyes more or less normal
Type of mouth/snout more or less normal
Position of mouth sub-terminal/inferior
Type of scales cycloid scales

Diagnosis: Body not strongly compressed, belly rounded before pelvic fins, with 4-9 pre-pelvic and 7-10 post-pelvic scutes, the pre-pelvic scutes ending below the pectoral fin base or behind it; in total 12-18 keeled scutes; maxilla short, reaching to just beyond front border of pre-operculum, tip pointed; gillrakers 18 to 26 (Ref. 189). It closely resembles Thryssa encrasicholoides, which has 1 or 2 small but armless keeled scutes immediately behind the isthmus, also maxilla tip blunter; other species of Thryssa have a complete series of pre-pelvic scutes from isthmus to pelvic fin base; Stolephorus species lack post-pelvic scutes; and Lycothrissa has canine teeth (Ref. 189).

Description: Body fusiform, not strongly compressed; body depth 21.8-27.3% of standard length (Ref. 28, 189, 122607). Head length 25.8-29.3% of standard length; snout length 4.1-5.7% of standard length; eye diameter 5.7-7.0% of standard length (Ref. 122607). Maxilla short; maxilla tip pointed, reaching just beyond lower jaw articulation; upper jaw length 22.7-26.6% of standard length, extension of maxilla beyond 2nd supra-maxilla 1.9-2.5% of standard length; lower jaw length 18.8-22.4% of standard length (Ref. 30573, 122607). Pseudobranch well-developed, slightly longer than eye diameter (Ref. 122607). Gillrakers moderately long and slender, 16-19 epibranchial and 20-23 ceratobranchial gillrakers; branchiostegal rays 12-14 (Ref. 122607). Dorsal fin with 3 unbranched and 11-13 branched rays; anal fin with 3 unbranched and 26-31 branched rays; pectoral fin with 1 unbranched and 12-13 branched rays; pelvic fin with 1 unbranched and 7 branched rays; anal fin origin behind last dorsal ray (Ref. 30573, 122607). Scales caducous, 37-38 in lateral series (Ref. 122607). Scutes present before and behind pelvic-fin base, total 12-18 scutes; no scutes before pectoral-fin origin; 4-9 pre-pelvic scutes and 7-10 post-pelvic scutes; occasionally, a single plate-like scute at isthmus (Ref. 28, 189, 30573, 122607).

Colouration: In alcohol, dorsal surfaces dark brown, flanks and lower part of body light brown or silvery; no silver stripe on flanks; fins hyaline (Ref. 122607).

Ease of Identification

Meristic characteristics of Thryssa baelama

Lateral Lines Interrupted: No
Scales on lateral line 37 - 38
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 18 - 26
on upper limb 16 - 19


Dorsal fin(s)

Attributes no striking attributes
Fins number 1
Finlets No. Dorsal   
Spines total 0 - 0
Soft-rays total 14 - 16
Adipose fin absent

Caudal fin

Attributes forked; more or less normal

Anal fin(s)

Fins number 1
Spines total 0 - 0
Soft-rays total 29 - 34

Paired fins

Pectoral Attributes  more or less normal
Spines     0
Soft-rays   13 - 14
Pelvics Attributes  more or less normal
Position    abdominal  before origin of D1
Spines     0
Soft-rays   8 - 8
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Binohlan, Crispina B.
Modified by Boden, Gert
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