Morfologiska data för Potamothrissa whiteheadi
Bestämningsnycklar
Abnormalities
Main Ref. Whitehead, P.J.P., 1985
Utseende refererar till
Bones in OsteoBase

Könskaraktärer

specialiserade organ no special organs
annat utseende males alike females
andra färger males alike females
Anmärkningar

Karaktäristiska egenskaper hos juveniler och adulter

Särskilt slående egenskaper none
Lateral kroppsform fusiform / normal
Tvärsnitt compressed
Dorsal profil av huvudet more or less straight
Ögontyp more or less normal
Typ av mun/snyte more or less normal
Munnens placering terminal
Type of scales cycloid scales
Diagnos

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

Meristiska karaktäristika för Potamothrissa whiteheadi

Sidolinjer avbruten: No
Fjäll längs sidolinje
Porbärande fjäll längs sidolinje
Fjäll i lateralserie 40 - 40
Antal rader fjäll ovan sidolinje
Antal rader fjäll under sidolinje
Fjäll runt stjärtfensspole
Skäggtömmar
Gälspringor (endast hos hajar/rockor)
Gälräfständer
på undre del av gälbåge 14 - 17
på övre del av gälbåge
totalt
Ryggkotor
preanal
totalt 42 - 42

Fenor

Ryggfena/fenor

Egenskaper no striking attributes
Antal fenor 1
Antal småfenor Dorsal   
Ventral  
Totalt antal hårda fenstrålar 0 - 0
Totalt antal mjuka fenstrålar 14 - 15
Fettfena absent

Stjärtfena

Egenskaper forked; more or less normal

Analfena/fenor

Antal fenor 1
Totalt antal hårda fenstrålar 0 - 0
Totalt antal mjuka fenstrålar 19 - 22

Pariga fenor

Bröstfena Egenskaper  more or less normal
Fenstrålar hårda     0
Fenstrålar mjuka   13 - 13
Bukfenor Egenskaper  more or less normal
Position    abdominal  behind origin of D1
Fenstrålar hårda     0
Fenstrålar mjuka   8 - 9
Main Ref. (t.ex. 9948)
Ordlista ( t.ex. cephalopods )
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