Morphology Data of Potamothrissa whiteheadi
Identification keys
Main Ref. Whitehead, P.J.P., 1985
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 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: Body slender, its depth 22-25% of standard length; pre-pelvic scutes not strongly keeled, beginning under or behind base of last pectoral finray, 8-10 pre-pelvic and 6-9 post-pelvic scutes, belly rounded; snout bluntly rounded; lower jaw not projecting, exactly meeting tip of upper jaw when mouth closed, deepest at mid-point of jaw, with small saw-like teeth on each side; pre-maxillae with small teeth pointing downward; maxilla very slender, its blade over 3 times as long as deep, upper edge ridged, lower edge without denticulations; posterior supra-maxilla minute, virtually without anterior shaft; lower gillrakers 14-17; silver stripe along flank, narrower anteriorly (Ref. 188, 28136). The presence of small horny denticles on snout and edges of mouth on the skin of the maxillary is typical for this species (Ref. 188, 93833). It closely resembles Potamothrissa obtusirostris, which lacks dermal denticles on the snout and has more post-pelvic scutes, 9-12 vs. 6-9; Potamothrissa acutirostris has a pointed snout and more gillrakers, 16-18 vs. 14-17 (Ref. 188, 28136). Other pellonulines lack saw-like teeth at the sides of the lower jaw (Ref. 188).

Description: Body slender, its depth 22-25% of standard length; head length 23.8-25.6% of standard length (Ref. 188, 93833). Caudal peduncle length 1-1.2 times in its depth (Ref. 93833). Presence of numerous horny denticles on the snout and edges of mouth up to the maxilla region (Ref. 28136, 93833). Interorbital width 1.2-1.4 times in eye diameter (Ref. 93833). Pre-maxillary teeth 20, mandibular teeth 24, maxillary teeth absent, 4-5 teeth on vomer and lingual teeth absent (Ref. 93833). Posterior supra-maxilla very small, with no or short shaft (Ref. 28136). With 14-17 gillrakers on lower part of first branchial arch (Ref. 93833). Dorsal fin with 14-15 rays; anal fin with 19-22 rays; pectoral fin with 13 rays; pelvic fin with 8-9 rays (Ref. 93833). Scales: about 40 in longitudinal series (Ref. 93833). With 8-10 pre-pelvic and 6-9 post-pelvic scutes, pre-pelvic scutes not strongly keeled, beginning under or behind base of last pectoral finray (Ref. 188, 28136). Total vertebrae 42 (Ref. 93833).

Colouration: Silvery, especially a lateral band with an underlying pigmented band, narrower anteriorly, more marked on the back; weak pigmentation at base of caudal fin and on both lobes; snout and occiput weakly pigmented (Ref. 188, 93833).

Ease of Identification

Meristic characteristics of Potamothrissa whiteheadi

Lateral Lines Interrupted: No
Scales on lateral line
Pored lateral line scales
Scales in lateral series 40 - 40
Scale rows above lateral line
Scale rows below lateral line
Scales around caudal peduncle
Gill clefts (sharks/rays only)
Gill rakers
on lower limb 14 - 17
on upper limb
total 42 - 42


Dorsal fin(s)

Attributes no striking attributes
Fins number 1
Finlets No. Dorsal   
Spines total 0 - 0
Soft-rays total 14 - 15
Adipose fin absent

Caudal fin

Attributes forked; more or less normal

Anal fin(s)

Fins number 1
Spines total 0 - 0
Soft-rays total 19 - 22

Paired fins

Pectoral Attributes  more or less normal
Spines     0
Soft-rays   13 - 13
Pelvics Attributes  more or less normal
Position    abdominal  behind origin of D1
Spines     0
Soft-rays   8 - 9
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Binohlan, Crispina B.
Modified by Boden, Gert
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