Chestnut Lamprey
  • Side view adult.
  • Side view adult.
  • Side view adult.
  • Top view adult: Flexible cylindrical body, typically 200-235 mm, max. 271 mm.
  • Bottom view adult: Flexible cylindrical body, typically 200-235 mm, max. 271 mm.
  • Head-on view adult: Cylindrical body with sucking disk.
  • Close-up flank: Body solid dark brown or gray, grading to light gray/brown to off-white ventrally.
  • Close-up head: Sucking disk greater in diameter than body diameter.
  • Close-up mouth and snout: Teeth are well-developed and sharp.
  • Close-up tail: Tail is rounded.
  • Close-up dorsal fin: It has two broadly connected lobes.
  • Close-up of teeth: Notice the bicuspid circumoral teeth and the closely spaced supraoral teeth.
  • Side view: Notice the connected dorsal fin and myomeres. Count myomeres from end of branchial pore to anus.
  • Close-up of dorsal fin: Notice the two broadly connected lobes.
  • Close-up of anterior region: Begin counting myomeres after the last branchial pore.
  • Close-up of teeth: Notice the bicuspid circumoral teeth and the closely spaced supraoral teeth.
  • Mouth of an ammocoete (larval stage): Juveniles have soft sieve-like tissue in the mouth.
  • Juvenile tail.
  • Whole body of an ammocoete (larval stage): Juveniles lack eyes and sucking disks.
  • Head of an ammocoete (larval stage): Juveniles have a hood-like mouth covering.
  • Lampreys will attach briefly but do not attempt to feed on people.
DescriptionSimilar Species
Family
Lampreys (Petromyzontidae)
Body
Mouth and Snout: Sucking disk in adults, flexible hood in juveniles. This parasitic species has a sucking disk that is larger in diameter than the rest of the body. The circumoral teeth are usually all or mostly bicuspid, with 4-5 circumoral teeth on each side. There are no barbels. Gill openings consist of seven circular holes. Body Pattern: Solid color. Dark brown or gray on dorsal surface and flanks, grading to light gray/brown, olive or off-white ventrally. Lateral pores pigmented. No scales Body Shape: Elongated, cylindrical, and flexible body. Typical adult size is 200-235 mm, with a maximum of 271 mm.
Fins
Rounded tail. Dorsal fin with no spines and two lobes. No anal, pectoral, pelvic, or adipose fins.
Distinguishing Characteristics
Eel-like body and sucking disk identify the lamprey family. First and second dorsal fin broadly connected. Pigmented lateral pores. Adults only: maximum disk diameter greater than maximum body diameter; supraoral lamina teeth cusps are close together, inner circumoral teeth are bicuspid. Maximum length 271 mm. 51-56 trunk myomeres. Sucking disk or hood, no jaw. Flexible, snake-like body. See also similar species information.
Breeding Adults
Lampreys spend most of their lives as ammocoetes. They transform to the adult form in the fall, cease feeding, breed in the spring, and die. The adult form is the breeding form.
Juveniles
Distinguished from adults based on head and mouth characteristics. Ammocoetes are a darkish brown without eyes or a sucking disk--the mouth has a hood-like covering without a papillary fringe, and has soft sieve-like tissue in the mouth.
Hybrids
None known from Wisconsin.
Compare Similar Species
1st and 2nd Dorsal Fins
Lamprey, American BrookSeparated
Lamprey, ChestnutConnected
Lamprey, Northern BrookConnected
Lamprey, SeaSeparated
Lamprey, SilverConnected
Lamprey, Southern BrookConnected
Trunk Myomeres
Lamprey, American Brook64-75
Lamprey, Chestnut51-56
Lamprey, Northern Brook46-56
Lamprey, Sea63-73
Lamprey, Silver46-53
Lamprey, Southern Brook49-57
Lateral Pores
Lamprey, American BrookUnpigmented
Lamprey, ChestnutPigmented
Lamprey, Northern BrookUnpigmented
Lamprey, SeaUnpigmented
Lamprey, SilverUnpigmented (pigmented in large adults)
Lamprey, Southern BrookPigmented
Maximum Disk Diameter Relative to Maximum Body Diameter in Adults
Lamprey, American BrookLess
Lamprey, ChestnutGreater
Lamprey, Northern BrookLess
Lamprey, SeaGreater
Lamprey, SilverGreater
Lamprey, Southern BrookLess
Supraoral Lamina Teeth
Lamprey, American BrookWidely Separated
Lamprey, ChestnutClose together
Lamprey, Northern BrookClose together
Lamprey, SeaClose together
Lamprey, SilverClose together
Lamprey, Southern BrookClose together
Inner Circumoral Teeth
Lamprey, American BrookBicuspid
Lamprey, ChestnutBicuspid
Lamprey, Northern BrookUnicuspid
Lamprey, SeaBicuspid
Lamprey, SilverUnicuspid (rarely 1 bicuspid)
Lamprey, Southern BrookBicuspid
Maximum Total Length (mm) in WI
Lamprey, American Brook202
Lamprey, Chestnut271
Lamprey, Northern Brook171
Lamprey, Sea760
Lamprey, Silver385
Lamprey, Southern Brook~170
Similarity Index
Lamprey, American BrookModerately similar
Lamprey, ChestnutN/A
Lamprey, Northern BrookVery similar as ammocoetes, moderately similar as adults
Lamprey, SeaModerately similar
Lamprey, SilverVery similar
Lamprey, Southern BrookVery similar as ammocoetes, moderately similar as adults
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