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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).
Issue
No study has specifically described ammocoetes of this species. Based on the
general statement in Potter (1968) and Potter et al. (1968) that ammocoetes of M. mordax are indistinguishable from those of M. praecox, the reader is advised to refer to the description of ammocoetes of M. mordax (Ref. 89241).
Environment: milieu / climate zone / depth range / distribution range
Ecology
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)
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. 130435)
Threat to humans
Harmless
Human uses
Fisheries: of no interest
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Estimates based on models
Phylogenetic diversity index (Ref.
82804): PD
50 = 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): 4.4 ±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).
