Petromyzonti (lampreys) > Petromyzontiformes
(Lampreys) > Mordaciidae
(Southern topeyed lampreys)
Etymology: Mordacia: Etymology not explained, likely derived from mordax (L.), biting, referring to specific name of M. mordax. (See ETYFish); praecox: Latin for premature, referring to its “precocious nature of sexual development,” wherein newly metamorphosed ammocoetes become sexually mature without first reaching their adult parasitic phase. (See ETYFish).
Environment: milieu / climate zone / depth range / distribution range
Freshwater; demersal; potamodromous (Ref. 51243). Temperate
Oceania: known only from the Moruya and Tuross Rivers in southern New South Wales, Australia.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 50.0 cm SL male/unsexed; (Ref. 44894); common length : 37.5 cm SL male/unsexed; (Ref. 44894)
Morphology | Morphometrics
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 <75%; caudal fin shape, spade-like; oral papillae, 33-48 (Ref. 89241).
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, 326-675
eggs/female (Ref. 89241).
Allen, G.R., 1989. Freshwater fishes of Australia. T.F.H. Publications, Inc., Neptune City, New Jersey. (Ref. 5259)
IUCN Red List Status (Ref. 125652)
Threat to humans
Fisheries: of no interest
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82804
= 0.7500 [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.00102 (0.00046 - 0.00225), b=3.06 (2.88 - 3.24), in cm total length, based on all LWR estimates for this body shape (Ref. 93245
Trophic level (Ref. 69278
): 4.5 ±0.8 se; based on size and trophs of closest relatives
Resilience (Ref. 120179
): Low, minimum population doubling time 4.5 - 14 years (Semelparous species, assuming tm (= tmax) > 4).
Fishing Vulnerability (Ref. 59153
): Moderate vulnerability (44 of 100).