Morphology Summary - Monotocheirodon duda
Morphology Data of Monotocheirodon duda
Identification keys
Abnormalities
Main Ref. Carvalho, T.P., A.T. Thomaz, A. Urbano-Bonilla and S. Prada-Pedreros, 2024
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance
Different colors
Remarks Adult males with enlarged urogenital papilla (none in females), its length about one-third to half of the first unbranched anal-fin ray, in contact with the first anal-fin unbranched ray; urogenital papilla covered by the sheath of enlarged scales on the anal fin; with highly modified anal fin with enlarged (anteroposteriorly) and distally elongated first and second anal-fin branched rays, forming a gonopodium like structure; have first branched rays distally expanded; no hooks were observed on the fins of mature males. Females with no highly enlarged anal-fin, rays have a concave posterior border (Ref. 132484).

Descriptive characteristics of juvenile and adult

Striking features
Body shape lateral  (shape guide)
Cross section compressed
Dorsal head profile
Type of eyes
Type of mouth/snout
Position of mouth
Type of scales
Diagnosis

The species is distinguished from all Stevardiinae species by the following set of characters: adult males with enlarged urogenital papilla (length about one-third to half of the first unbranched ray), which is in contact with the first anal-fin unbranched ray and a highly modified anal fin, with enlarged (anteroposteriorly) and distally elongated first and second branched anal-fin rays, forming a gonopodium-like structure; differs from its congenerspresence of an adipose fin (vs. absent); lateral line incomplete, pored scales not reaching the caudal fin (vs. lateral line complete); ascending process of the premaxilla dorsally directed (vs. strongly bent posteroventrally); snout longe, about a fourth of the head length (HL), between 23.1%- 30.0% of HL (vs. short snout, <20% of the HL) (Ref. 132484).

Ease of Identification

Meristic characteristics of Monotocheirodon duda

Lateral Lines Interrupted: No
Scales on lateral line
Pored lateral line scales 28 - 34
Scales in lateral series
Scale rows above lateral line
Scale rows below lateral line
Scales around caudal peduncle
Barbels
Gill clefts (sharks/rays only)
Gill rakers
on lower limb 7 - 11
on upper limb 5 - 7
total
Vertebrae
preanal 14 - 16
total 36 - 37

Fins

Dorsal fin(s)

Attributes
Fins number
Finlets No. Dorsal   
Ventral  
Spines total
Soft-rays total 7 - 7
Adipose fin

Caudal fin  (shape guide)

Attributes

Anal fin(s)

Fins number
Spines total
Soft-rays total 11 - 13

Paired fins

Pectoral Attributes  
Spines     
Soft-rays   9 - 11
Pelvics Attributes  
Position    
Spines     
Soft-rays   6 - 6
(e.g. 9948)
(e.g. oophagy)
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cfm script by eagbayani, 17.10.00, php script by rolavides, 13/03/08 ,  last modified by sortiz, 06.27.17