Australian Brook Lamprey

Adults: 10.2-172 mm TL; body proportions, as percentage of TL: 9.4-12.6 prebranchial length, 8.2-9.9 branchial length, 59.6-64.2 trunk length, 16.5-20.4 tail length, 1.3-1.5 eye length and 5.4-8.4 disc length; no gular pouch develops; urogenital papilla not prominent in mature adults; trunk myomeres, 85-93. Adult dentition: 2 triangular supraoral laminae each with 3 unicuspid teeth, 1 per apex (exceptionally, 4 unicuspid teeth per supraoral lamina); Infraoral lamina, 9-10 unicuspid teeth of various size (these teeth become greatly enlarged with sexual maturation); 5-6 endolaterals on each side; endolateral formula, typically 2-2-3-3-4-3 or 2-2-3-3-4-4 in immature individuals and 1-1-1-1-1 or 1-1-1-1-1-1 in mature individuals; 1 row of anterials; first row of anterials, 2 unicuspid teeth flanked on either side by one bicuspid tooth in immature individuals and 4 unicuspid teeth in mature individuals; 1-2 rows of exolaterals on each side; 1 row of posterials; first row of posterials, 16 posterial plates, the three lateralmost tricuspid and the internal ones bicuspid in immature individuals and 13 unicuspid teeth in mature individuals; transverse lingual lamina w-shaped with numerous unicuspid teeth of various size, the middle apex one being intermediate in size and the two bottom apex ones being largest, while the rest are small; longitudinal lingual laminae hook-shaped each with an undetermined number of unicuspid teeth. Body coloration (live) of mature adults with dark blue dorsal surface, occasionally with a green tinge, ventral surface of males mottled gray and ventral surface of females yellowish; extent of caudal fin pigmentation, 25% to

Potamodromous. Migrating within streams, migratory in rivers, e.g. Saliminus, Moxostoma, Labeo. Migrations should be cyclical and predictable and cover more than 100 km.

Inhabits freshwater streams, a non-parasitic lamprey that spends its entire life cycle in freshwater. Ammocoetes burrow in soft substrates, phase lasts about 3 years; metamorphosis usually occurs between October and November. Presumed to migrate upstream around April, and spawns in late winter or spring (Ref. 44894). Fecundity, 326-675eggs/female (Ref. 89241).

fisheries: of no interest

Mordacia praecox, the Australian brook lamprey or nonparasitic lamprey, is a freshwater species of southern topeyed lamprey that occurs in south-eastern Australia. It has a thin eel-like body around 12 to 15 cm long, with two low dorsal fins on the back half. The skin is dark blue above and gray below. Its eyes are small, and located on the top of its head. Unlike M. mordax, M. praecox's eyes appear to have the potential for dichromatic vision (despite being similarly adapted for low-light environments).

M. praecox is known only from the Moruya and Tuross Rivers in southern New South Wales. Unlike most other species of lampreys, it spends its entire life in fresh water. The ammocoetes (lamprey larvae) take around three years to reach maturity. Ammocoetes and juvenile adults are indistinguishable from those of M. mordax, which also occurs within its distribution, but the adults are easily distinguished by their size and colouration.