Morphology Data of Nothobranchius streltsovi
Identification keys
Main Ref. Valdesalici, S., 2016
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance always different morphology between mature adults
Different colors always different colors between mature adults
Remarks Female: anal fin triangular with rounded tip; pelvic fin short, tip not reaching anus; branchiostegal membrane not projecting from opercle; urogenital papilla surrounded by an expanded membrane forming a pocket shaped structure overlapping anterior portion of anal fin (Ref. 116792).

Descriptive characteristics of juvenile and adult

Striking features
Body shape lateral fusiform / normal
Cross section
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth superior
Type of scales

Diagnosis: Nothobranchius streltsovi males are similar to other members of the N. ugandensis species group in possessing light blue scales with a broad, irregular, reticulated pattern on the body, oblique red or orange bars on the head and dorsum, yellow or blue anal fin, large vivid red spots on the dorsal and anal fins, rounded head with slightly concave to nearly straight dorsal profile, convex predorsal profile from nape to posterior extremity of dorsal-fin base, and variable cephalic squamation; males can be distinguished from all other species of this species group by the following combination of characters: scale margins orange; caudal fin orange, spotted proximally; pectoral fin spotted proximally; anal and pelvic fins with a pattern of red dots, light blue proximally, yellow or creamy white distally; seven branchiostegal rays; 31-34 longitudinal scales; 14-16 transverse scales; 15-16 circumpeduncular scales; supraorbital neuromast formula 2+3+4 (Ref. 116792).

Description: Dorsal profile of head straight to slightly concave anteriorly, convex from nape to posterior extremity of dorsal-fin base; ventral profile convex, slightly concave to nearly straight on caudal peduncle posterior to anal fin; snout slightly pointed, mouth superior, lower jaw longer than upper, posterior end of rictus at same level or slightly above centre of eye; branchiostegal membrane projecting posteriorly from opercle (Ref. 116792). Dorsal anal-fin origins posterior to mid-body, rounded, fin tips with short filamentous rays; tip of dorsal fin reaching caudal fin; dorsal and anal-fins covered with an opaque mucus film with papillate contact organs on anal-fin rays; pectoral fin approximately triangular, tip not reaching pelvic fin; pelvic fin short, tip reaching anus; caudal fin subtruncate; dorsal-fin rays 16-18; anal-fin rays 16-18; caudal-fin rays 30-33; pectoral-fin rays 18-20; pelvic-fin rays 6 (Ref. 116792). Scales cycloid, body and head entirely scaled, except for ventral surface of head; cephalic squamation pattern irregular; scales in midlateral series 31-34, + 5-6 on caudal-fin base; transverse scales 14-16; circumpeduncular scales 15-16 (Ref. 116792). Frontal neuromast pattern 'open' type; anterior supraorbital neuromast series in a shallow groove with 3 neuromasts; posterior supraorbital neuromast series curved with 4 neuromasts; cephalic neuromasts: supraorbital 2+3+4; preopercular neuromast series in an open groove, distal ridge slightly overlapping opercle; one neuromast on each scale of midlateral longitudinal series (Ref. 116792). Basihyal bone sub-triangular, basihyal cartilage spatulate; seven branchiostegal rays; three vomerine teeth in a small patch; lateral process of post-temporal short; urohyal, with a single antero-dorsal process; second pharyngobranchial with one tooth; total number of vertebrae 32; premaxilla and dentary with many irregularly distributed, unicuspid, slightly curved teeth of variable size, a small number of larger teeth on outer row in both jaws (Ref. 116792).

Colouration: In life, males exist in two sympatric colour morphs: flank light blue with orange reticulations; side of head light blue with orange reticulations; anterior, superior portion of head, dentary, and lower jaw orange; iris silvery with golden sheen, a faint black vertical bar through the centre of eye; branchiostegal membrane orange with white rim; dorsal fin light blue with dark red spots and dots, larger basally, smaller distally; in white morph anal fin light blue with rows of red spots and dots on basal portion, creamy white with red tip on distal half; in yellow morph anal fin light blue with rows of red spots and dots on basal portion, elongate over median rays, yellow on distal half; dorsal and anal fins with dark brown to black margin; caudal fin orange, light blue with red spots on basal portion; pectoral fin hyaline orange with dark orange to red dots on basal portion, light blue posterior margin; in white morph pelvic fin light blue with elongate red spots, distal portion creamy white; in yellow morph pelvic fin light blue with elongate spots, distal portion yellow (Ref. 116792). In life, females with following colouration: body and head scales light brown-grey, ventrally whitish; posterior scale margins darker, forming a reticulated pattern; opercular region whitish with light blue reflection; scales on dorsal surface and upper part of flank reflective light blue posteriorly; fins hyaline; iris silvery (Ref. 116792).

Ease of Identification

Meristic characteristics of Nothobranchius streltsovi

Lateral Lines Interrupted: No
Scales on lateral line
Pored lateral line scales
Scales in lateral series 36 - 40
Scale rows above lateral line
Scale rows below lateral line
Scales around caudal peduncle 15 - 16
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
total 32 - 32


Dorsal fin(s)

Attributes no striking attributes
Fins number 1
Finlets No. Dorsal   
Spines total 0 - 0
Soft-rays total 16 - 18
Adipose fin absent

Caudal fin

Attributes more or less truncate; more or less normal

Anal fin(s)

Fins number 1
Spines total 0 - 0
Soft-rays total 16 - 18

Paired fins

Pectoral Attributes  more or less normal
Spines     0
Soft-rays   18 - 20
Pelvics Attributes  more or less normal
Position    abdominal  before origin of D1
Spines     0
Soft-rays   6 - 6
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Boden, Gert
Modified by Boden, Gert
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