Morphology Data of Characidium helmeri
Identification keys
Abnormalities
Main Ref. Zanata, A.M., L.M. Sarmento-Soares and R.F. Martins-Pinheiro, 2015
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance
Different colors
Remarks

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 sub-terminal/inferior
Type of scales cycloid scales
Diagnosis

Characidium helmeri is distinguished from other species of Characidium by possessing dark, vertically elongated, irregular, narrow spots or dashes, usually more evident over the midlateral stripe and/or ventral half of body, formed by high concentration of melanophores on the posterior half of scales, occurring in a somewhat curved or zigzag-shape. It also differs from congeners by having extremely reduced or complete absence of supraorbital. It further differs by having lateral line reduced (vs. complete, except in C. bahiense, C. interruptum, C. laterale, C. mirim, C. nupelia, C. rachovii, C. stigmosum and C. xavante), adipose fin absent (vs. present, except in C. mirim, C. nupelia, C. stigmosum, and C. xavante), and isthmus naked on its anteriormost portion (vs. isthmus completely covered by scales in most congeners, except in C. alipioi, C. boavistae, C. crandellii, C. declivirostre, C. fasciatum, C. gomesi, C. grajahuensis, C. japuhybense, C. lauroi, C. macrolepidotum, C. oiticicai, C. schubarti, C. timbuiense, and C. vidali). It can be diagnosed from C. bahiense, C. interruptum, C. laterale, C. mirim, C. nupelia, C. rachovii and C. xavante by having more pored lateral line scales 13-22 (vs. 5-11) and two series of dentary teeth (vs. one). It can be further separated from C. nupelia and C. xavante by the absence of a dark humeral blotch (vs. presence) smaller number of dark vertical bars on the body, 7-12 when present (vs. 12-18). It is distinct from C. vestigipinne, a species with adipose fin absent or reduced, by having two dentary rows of teeth, the outer with tricuspid teeth (vs. one row of conical teeth), 4 scales above lateral line and 4 below (vs. 5 above; and 5 or 6 below), and absence of roundish black marks on pelvic, dorsal, and anal fins (vs. presence). It further differs from C. stigmosum by having a black basicaudal dot (vs. absence), and by having pelvic, pectoral, anal, and caudal fins not dark pigmented in males (vs. pigmented) (Ref. 104900).

Description: Dorsal-fin rays ii,9, ii,10, iii,9 or iii,10. Anal-fin rays ii,5 or ii,6; iii,6. Pectoral-fin rays 8-12 total rays, number of unbranched rays highly variable; unbranched anterior rays ii, iii, iii, iv, ix and posteriormost rays varying from by 1-4 unbranched; one specimen with all rays unbranched. Pelvic-fin rays highly variable, i,4,iii, i,4,iv, i,5,i , i,5,ii, i,5,iii, i,6,i, i,6,ii, ii,6,ii, i,7, i,7,i, or i,8,i (Ref. 104900).

Ease of Identification

Meristic characteristics of Characidium helmeri

Lateral Lines Interrupted: No
Scales on lateral line
Pored lateral line scales 13 - 22
Scales in lateral series 30 - 33
Scale rows above lateral line 4 - 4
Scale rows below lateral line 4 - 4
Scales around caudal peduncle 13 - 14
Barbels
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
total
Vertebrae
preanal 18 - 19
total 33 - 35

Fins

Dorsal fin(s)

Attributes no striking attributes
Fins number 1
Finlets No. Dorsal   
Ventral  
Spines total
Soft-rays total 11 - 13
Adipose fin absent

Caudal fin

Attributes forked

Anal fin(s)

Fins number
Spines total
Soft-rays total 7 - 9

Paired fins

Pectoral Attributes  more or less normal
Spines     
Soft-rays   8 - 12
Pelvics Attributes  more or less normal
Position    abdominal  behind origin of D1
Spines     
Soft-rays   7 - 10
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Torres, Armi G.
Modified by Torres, Armi G.
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