Morphology Data of Paramormyrops sphekodes
Identification keys
Abnormalities
Main Ref. Rich, M., J.P. Sullivan and C.D. Hopkins, 2017
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

Diagnosis: Paramormyrops sphekodes is distinguished from all other Paramormyrops by this combination of characters: 5 teeth in upper jaw, 6 in lower; 12 circumpeduncular scales; sharp head profile, V-shaped when viewed from above; snout angle 48-56° corresponding to an interorbital width 1-1.36 times the snout length; body depth 15.4-17.31% of standard length, body depth at pectoral fin 84-94% of body depth at urogenital pore; eye diameter 13-16% of head length measured from snout tip to posterior edge of bony operculum; snout length 24-27% of head length; ration of head length to depth 1.1-1.24; head length 21-23% of standard length; EOD waveform with two phases, head-positive then negative, EOD duration 1.635 ± 0.226 ms with a corresponding power spectrum peak at 1573 ± 531 Hz; electric organ composed of type NPp electrocytes, that is having Non-Penetrating stalks innervated on the posterior face of the cell (Ref. 116799). With five teeth in the upper jaw and six in the lower, P. sphekodes differs from P. hopkinsi, P. jacksoni and P. tavernei, which have seven or more teeth in the upper jaw and eight or more in the lower jaw; with 12 circumpeduncular scales, it differs from P. longicaudatus, P. batesii and P. tavernei, which all have 16 or more; with its relatively sharp V-shaped head profile, it differs from P. batesii, P. gabonensis, P. retrodorsalis, P. tavernei and P. kingsleyae which have distinctly blunt or U-shaped snouts; Paramormyrops sphekodes has type NPp electrocytes in its electric organ, as do seven other Paramormyrops from Lower Guinea, while P. batesii and P. kingsleyae have electric organs composed of electrocytes with penetrating stalks innervated on the anterior face (Ref. 116799). Paramormyrops sphekodes differs from P. curvifrons in head and snout shape; head and snout are shorter, deeper and more rounded when viewed laterally in P. sphekodes compared to P. curvifrons; Paramormyrops curvifrons also has a downward sloping forehead, protruding snout and enlarged chin; the ratio head length to standard length is 23.5-26.9 in P. curvifrons, higher than 21.5-23.4 in P. sphekodes, while the ratio of head depth to head length is reduced in P. curvifrons compared to P. sphekodes; the ratio of pre-pectoral distance to pre-dorsal distance is greater in P. curvifrons compared to P. sphekodes, and P. curvifrons has a significantly narrower snout than P. sphekodes measured by either snout angle or ratio interorbital width to snout length (Ref. 116799).

Description: A small-bodied Paramormyrops; body laterally compressed, maximum width at opercular bones; viewed laterally, dorsal and ventral profile nearly parallel from behind the head to the first anal ray; median body depth 16.1% of standard length at pectoral fin, 17.6% of standard length at the urogenital pore; the ratio of these two body depths 84-89%, indicating that the depth changes little from anterior to posterior of the body anterior of the anal fin; caudal peduncle length 17-20% of standard length, slightly wider at its origin than middle, depth 25-29% of caudal peduncle length; lobes of caudal fin rounded (Ref. 81635, 116799). Lateral head profile above eye usually gently convex to very slightly concave in some individuals; snout short and smoothly rounded; forehead downward-sloping from halfway between opercular opening and snout tip; tip of the snout one half eye diameter below the ventral margin of the eye; viewed dorsally, head and snout V-shaped or sharp, median snout angle 53.6° (Ref. 81635, 116799). Mouth small, rictus directly beneath nares; chin protrudes slightly below gular region, not extending beyond snout; eye small, eye diameter 11-14% of head length, positioned mid-laterally; eye socket forms pale ring around pigmented eye, with gold iris and dark centre; interorbital width 26.8-29.3% of head length; anterior naris about 1/3 distance from snout tip to eye, slightly below line drawn through the centre of eye, posterior naris halfway between anterior naris and eye, at about level of eye's lower margin; opercular opening begins anterior to base of pectoral fin; postorbital length 60-68% of head length (Ref. 116799). Pectoral-fin origin beneath posterior terminus of opercular opening, slightly below mid-horizontal line, length 12.4-17.0% of standard length, 11 rays; pelvic-fin origin at 35.0-38.8% of standard length, length 9.2-10.8% of standard length, positioned ventrally, 6 rays; dorsal-fin origin at 64-65% of standard length; anterior margin gently convex, trailing margin concave in first third, remainder levels off at 1/2 dorsal fin height; maximum height 62.3-79.2% of dorsal fin length, 20-23 total rays; anal-fin origin slightly anterior to dorsal-fin origin; dorsal-fin origin above seventh, or fifth branched, anal-fin ray; anal fin mirrors general shape of dorsal fin, maximum height 45.2-65.0% of anal fin length; in males, anterior anal fin ray thickened and stiff with a noticeable notch at the base of the anal fin, spanning anterior half of anal-fin base; end of anal-fin base terminus directly beneath end of dorsal-fin base, rays 24-28; lobes of caudal fin rounded, equal, slightly wider than caudal peduncle, deeply cleft, scaled at their bases (Ref. 116799). Scales fine, cycloid, absent from head; pierced lateral line scales, 63-72; scales between lateral line and anterior base of dorsal fin 9-11, 10-15 scale rows between pelvic fin and lateral line; circumpeduncular scales 12 (Ref. 116799). Vertebrae: 43-45 total, 18-19 precaudal, 24-26 caudal (Ref. 116799). Teeth bicuspid, 5 in upper, 6 in lower jaw (Ref. 116799).

Colouration: All fins with lightly pigmented rays, membranes hyaline; dark band absent between dorsal and anal fins; body darker dorsally, lighter ventrally (Ref. 116799). When alive, tan-brown body with yellow-olive or golden accents on top of head, back, and belly; mouth, chin, and gular region unpigmented, whitish; many small unpigmented spots and pores over electroreceptors visible on top of head and back, with fewer, large white spots (knollenorgans) on head (Ref. 116799). Preserved specimens uniform greyish-brown (Ref. 81635, 116799).

Ease of Identification

Meristic characteristics of Paramormyrops sphekodes

Lateral Lines Interrupted: No
Scales on lateral line 63 - 72
Pored lateral line scales
Scales in lateral series
Scale rows above lateral line 9 - 11
Scale rows below lateral line 10 - 15
Scales around caudal peduncle 12 - 12
Barbels
Gill clefts (sharks/rays only)
Gill rakers
on lower limb
on upper limb
total
Vertebrae
preanal
total 43 - 45

Fins

Dorsal fin(s)

Attributes no striking attributes
Fins number 1
Finlets No. Dorsal   
Ventral  
Spines total 0 - 0
Soft-rays total 20 - 23
Adipose fin absent

Caudal fin

Attributes forked; more or less normal

Anal fin(s)

Fins number 1
Spines total 0 - 0
Soft-rays total 24 - 28

Paired fins

Pectoral Attributes  more or less normal
Spines     0
Soft-rays   11 - 11
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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