Freshwater Fishes of Texas: A Field Guide

Lampreys—Family Petromyzontidae

1 Lampreys—Family Petromyzontidae Chestnut lamprey Ichthyomyzon castaneus Girard, 1858 RANGE: Red, Sabine, and Neches river basins. HABITAT: Lakes and creeks. Parasitic adults are found in open water areas often attached to other fish. CHARACTERISTICS: (1) Sucking disc wider than head; disc length contained 14.3 times in total length. (2) Teeth of sucking disc sharp and well developed. (3) Single median nostril. (4) Seven gill openings. (5) Myomeres (muscle segments): 47–58. (6) Intestine well developed. DIMENSIONS: Up to 15 in (381 mm). COLORATION: Dorsal and lateral regions yellow or brown; ventral region olive-yellow to white. After spawning, adults take on a blue-black coloration. COMMENTS: During spawning, adults migrate to headwater streams and use their sucking disc to carry stones to excavate and maintain nest pits. See southern brook lamprey, Ichthyomyzon gagei. Chestnut lamprey, Ichthyomyzon castaneus, 6.2 in (157 mm) Chestnut lamprey, Ichthyomyzon castaneus, view of sucking disc 16 Southern Brook lamprey Ichthyomyzon gagei Hubbs and Trautman, 1937 RANGE: Red, Trinity, San Jacinto, Sabine, and Neches river basins. HABITAT: Rivers and creeks. CHARACTERISTICS: (1) Sucking disc small; disc length contained 17.2 to 26.3 times in total length. (2) Teeth in posterior field (or entire field) of sucking disc poorly developed. (3) Single median nostril. (4) Gill openings: 7. (5) Myomeres (muscle segments): 40–59. Lampreys—Family Petromyzontidae Southern brook lamprey, Ichthyomyzon gagei, ammocoete, 2.5 in (63.5 mm) Southern brook lamprey, Ichthyomyzon gagei, adult, 6 in (152 mm) Southern brook lamprey, Ichthyomyzon gagei, view of sucking disc (6) Intestine poorly developed. DIMENSIONS: Up to 7 in (178 mm). COLORATION: Dorsal and lateral regions gray or olive; ventral region yellow. COMMENTS: Adults use the sucking disc to carry stones to build and maintain nest pits. Nonparasitic adults move upstream to spawn and then die. Ammocoetes (larval form) burrow into the substrate of rivers and creeks where they filter feed for a year or more before maturing into adults. The southern brook lamprey can be distinguished from the chestnut lamprey by the small mouth disc and small adult size. The two species might also be distinguished from one another in that the adult southern brook lamprey is a nonparasitic form with a poorly developed intestine whereas the adult chestnut lamprey is parasitic with a well-developed intestine. ...