Morphology Data of Lampetra fluviatilis
Identification keys
Abnormalities
Main Ref. Allardi, J. and P. Keith, 1991
Appearance refers to
Bones in OsteoBase

Sex attributes

Specialized organs no special organs
Different appearance males alike females
Different colors males alike females
Remarks

Descriptive characteristics of juvenile and adult

Striking features striking type of mouth
Body shape lateral eel-like
Cross section circular
Dorsal head profile clearly convex
Type of eyes more or less normal
Type of mouth/snout sucker-like
Position of mouth sub-terminal/inferior
Type of scales scales embedded or partly/completely absent
Diagnosis

It is jawless with a round sucker-like mouth and has an outer circle of small teeth and an inner circle of large teeth (Ref. 88171). It has a typical eel-like shape with 2 dorsal fins and 7 gill openings behind the eye. It lacks paired fins. Young adults are uniformly greyish in colour. As it ages, the river lamprey becomes greenish-brown dorsally, golden yellow along the sides and white ventrally (Ref. 58137). In coastal waters of Germany, it can be confused with the sea lamprey (Petromyzon marinus), which is distinguished by having its teeth arranged in many consecutive circular rows (Ref. 88171). Other diagnostic features: Adults 8.6-49.2 cm TL. Body wet weight in individuals 18.0-49.2 cm TL, 30-150 g. Body proportions, as percentage of TL (based on 48 specimens measuring 10.8-38.6 cm TL): prebranchial length, 10.0-12.9; branchial length, 7.9-11.3; trunk length, 46.2-54.3; tail length, 24.1-30.3; eye length, 1.4-3.1; disc length, 4.6-7.0. Urogenital papilla length, as a percentage of branchial length, in 19 spawning males measuring 19.7-28.3 cm TL, 15.9-37.5. Trunk myomeres, 58-66. Dentition: marginals, 70-95; supraoral lamina, 2 unicuspid teeth; infraoral lamina, 5-9 either all unicuspid teeth or, more frequently, the lateralmost are bicuspid and the internal ones unicuspid; 3 endolaterals on each side; endolateral formula, typically 2-3-2, rarely 1-3-2 or 2-3-1; 1-2 rows of anterials; first row of anterials, 4-7 unicuspid teeth; exolaterals absent; posterials absent; transverse lingual lamina, 8-18, usually 12-14, unicuspid laminae straight or parentheses-shaped and each with 9-13 unicuspid teeth. Marginal membrane present. Velar tentacles, 4-10, with tubercles; no velar wings. Body coloration in recently metamorphosed individuals silvery; in preserved upstream migrants, bluish brown or lead gray on the dorsal aspect tending towards silvery on the lateral aspects and whitish or yellowish on ventral aspect. Early upstream spawning migrants returning from the sea have a bronze sheen. Dorsal fins of maturing individuals may have a purplish tint. Iris is golden yellow. Body coloration in the landlocked population in Lake Ladoga is completely black. Lateral line neuromasts unpigmented or darkly pigmented. Extent of caudal fin pigmentation, absent or trace in young adults and 75% or more in spawning individuals. Caudal fin shape, spade-like. Oral fimbriae, 84-112. Oral papillae, 11-20 (Ref. 89241).

Ease of Identification likely to be confused with closely related species.

Meristic characteristics of Lampetra fluviatilis

Lateral Lines Interrupted: No
Scales on lateral line 0 - 0
Pored lateral line scales 0 - 0
Scales in lateral series 0 - 0
Scale rows above lateral line 0 - 0
Scale rows below lateral line 0 - 0
Scales around caudal peduncle 0 - 0
Barbels 0
Gill clefts (sharks/rays only) 7
Gill rakers
on lower limb
on upper limb
total
Vertebrae
preanal
total

Fins

Dorsal fin(s)

Attributes no striking attributes
Fins number 2
Finlets No. Dorsal   0 - 0
Ventral  0 - 0
Spines total 0 - 0
Soft-rays total
Adipose fin absent

Caudal fin

Attributes pointed; confluent

Anal fin(s)

Fins number
Spines total 0 - 0
Soft-rays total 0 - 0

Paired fins

Pectoral Attributes  absent
Spines     0
Soft-rays   0 - 0
Pelvics Attributes  suppressed/absent
Position    absent
Spines     0
Soft-rays   0 - 0
Main Ref. (e.g. 9948)
Glossary ( e.g. cephalopods )
Entered by Palomares, Maria Lourdes D.
Modified by Hilomen, Teresa
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