Morphology Data of Tylochromis microdon
Identification keys
Abnormalities
Main Ref. Stiassny, M.L.J., 1989
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs
Different appearance always different morphology between mature adults
Different colors
Remarks Sexual dimorphism is evident at a relatively small size and a slight coarsening of the outer row teeth is discernible in males of 7cm SL (Ref. 52346).

Descriptive characteristics of juvenile and adult

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

Diagnosis: marked hypertrophy of lateral line canals on flank and caudal fin; inflated preopercular laterosensory canals; distinctive excavation of premaxillary oral valve (Ref. 52346).

Description: moderately deep-bodied; predorsal contour somewhat rounded, being steep over snout, decreasing sharply over eye then rising again to origin of dorsal fin (Ref. 52307, 52346). Deepest body depth along back at or just behind dorsal fin origin; lower jaw more or less along horizontal when mouth is closed; lower jaw slender and gracile (Ref. 52346). Lips thin compared to congeners (Ref. 52307, 52346). Pharyngeal apophysis of Tylochromis type (Ref. 53524). Premaxillary oral valve (= diaphragm of skin that extends across inner edge of upper jaws) forming a flap at entrance to buccal cavity; premaxillary valve deeply excavated medially (Ref. 52346). Eyes relatively large (Ref. 52307). Widely spaced, stout, crenate gill-rakers along outer row of lower limb of first arch; first and second hypobranchial rakers frequently elongate and without crenations; stout epibranchial rakers along upper limb of first arch; vertebral apophysis borne on third and fourth vertebral centra and of standard Tylochromis type; 33-37 lateral line scales; upper branch of lateral line terminates well in advance of end of soft dorsal, often as far back as beneath 9th-10th soft dorsal ray from free end of fin; terminal canal bearing scales do not descend scale rows; in both upper and lower lateral line series pores and canals inflated and prominent; dorsal and ventral lateral line branches on caudal fin also inflated and extending almost to fin periphery; medial branch not noticably inflated but also extending almost to caudal periphery; dorsal fin spines gradually increase to 4th-5th and are then more or less equal in length; anal fin rounded; pectoral fin relatively elongate and normally reaching origin of spinous anal; first branched pelvic ray produced and filamentous, frequently reaching origin of soft anal in ripe males but less produced in females and juveniles (Ref. 52346). Caudal fin slightly forked (Ref. 52307) and finely scaled usually almost to periphery; caudal scaling denser in mature males than in females (Ref. 52346).

Coloration: brownish with a darker back (Ref. 52307). Ethmoidal, preorbital, opercular areas and upper lip dark grey-black; mature males with entire dorsal head surface dark, and separate nape band or opercular blotch not evident; females with less dense head pigmentation and traces of nape band usually evident; blue-black band in neck well developed in males, less developed or absent in females (Ref. 52346). Often with light band directly behind opercle (Ref. 52307). Chest, ventrum, belly, lower lip, jaw and branchiostegal membranes in both sexes creamy yellow (Ref. 52346). Body scales silvery to yellowish with dark margins (Ref. 52307), resulting in appearance of series of longitudinal striations passing through scale rows (Ref. 52346). No traces of vertrical striping in adults, although faint traces of 5-7 stripes evident in juveniles; dorsum dark smokey-grey in mature males but slightly less dark in females and juveniles; dorsal fin in mature males proximally dark smokey grey-black but in membranous interspace between each ray a single large whitish macula is present; distally the membranous interspaces lighter, almost translucent grey, and another row of large whitish maculae is usually present; dorsal fin maculae more numerous and smaller in females and juveniles; anal fin of both sexes unusually patterned, without traces of typical Tylochromis maculae, but with a uniform dark smokey grey soft anal with a single white band traversing it medially; filamentous extension of first pelvic ray creamy white while rest of fin is smokey grey; caudal fin in both sexes smokey grey with a few thin dark stripes in central region in mature males (Ref. 52346).

Ease of Identification

Meristic characteristics of Tylochromis microdon

Lateral Lines Interrupted: No
Scales on lateral line
Pored lateral line scales
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 14 - 17
on upper limb 8 - 9
total
Vertebrae
preanal
total 28 - 29

Fins

Dorsal fin(s)

Attributes
Fins number 1
Finlets No. Dorsal   0
Ventral  0
Spines total 14 - 15
Soft-rays total 12 - 15
Adipose fin absent

Caudal fin

Attributes

Anal fin(s)

Fins number 1
Spines total
Soft-rays total 7 - 7

Paired fins

Pectoral Attributes  
Spines     
Soft-rays   
Pelvics Attributes  
Position    
Spines     
Soft-rays   
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
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