Diagnostic description

Diagnosis

Nannocharax signifer is distinguished from all other Nannocharax species in West Africa by the red-orange colouration of the anterior part of its dorsal fin

The combination of the following characters is also diagnostic: 

  • no continuous black band along the flank
  • multiple x-shaped body colour pattern extending on the lower half of the flank
  • 46-48 (usually 47) lateral line scales
  • 4-5 scales between anus and origin of anal fin

Description

Based on holotype and twelve paratypes

  • Size medium to large sized Nannocharax species with 
    • 60mm SL 
    • more than 70 mmTL. 
  • Body shape typical for Nannocharax: 
    • elongated with a slender body
    • oval in cross section
    • only slightly laterally compressed
  • Head pointed, mouth small and subterminal 
  • Eye slightly closer to tip of snout than to end of head 
    • eye diameter about 1/3 of head length
  • Body depth greatest directly in front of dorsal fin
  • Body completely covered with ctenoid scales
    • lateral line complete
    • straight along body
    • with 46 to 48, usually 47 scales
    • 4.5 scale rows between lateral line and origin of dorsal fin 
    • 4.5 rows between lateral line and origin of pelvic fin
    • 14 scale rows around caudal peduncle
  • Dorsal fin 
    • at about middle of body
    • with 3-4 simple rays of which 
      • 1-2 are supernumerary
    • dorsal-fin origin at vertical through pelvic-fin origin or slightly behind. 
  • Caudal fin
    • deeply bifurcate with equal lobes
    • 9 dorsal procurrent rays 
    • 10 upper principal rays 
    • 9 lower principal rays 
    • 8 ventral procurrent rays
  • Pectoral fin
    • with 14-16 rays, usually 14
    • tip of -fin behind origin of pelvic fin
  • Pelvic fins 
    • well separated from each other, with 9 rays
  • Anal fin 
    • with10-11 rays, usually 10
  • Vertebrae
    • Usually 38 vertebrae in total 
    • rarely 39
    • 19 abdominal and 19 caudal vertebrae