Classification / Names
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Petromyzonti (lampreys) >
Petromyzontiformes (Lampreys) >
Geotriidae (Southern lampreys)
Etymology: Geotria: Etymology not explained, although three possibilities, all problematical, have been proposed: (1) from the Greek geotragia, “eating of earth-like substances,” referring to how this lamprey, like other lampreys, uses its suctorial mouth to attach itself to submerged rocks and stones, thus creating the impression that it is feeding on the earth (problem: geotragia does not mean “earthy,” as in rocks and minerals, but “products of the earth,” such as grains and vegetables; (2) geo- (Gr.), earth, and atrium (L.), room, referring to this lamprey’s nest, presumably made of stones and pebbles assembled by one or both parents (problem: nest-building, while known in other river lampreys, was probably not known to Gray in 1851 and has not been documented for this species); (3) a variation of #2, proposed by Meagher (2010), referring to its discovery in underground chambers, in which it survives dry periods (problem: G. australis does not, nor does any other lamprey, aestivate, nor did Gray indicate it was discovered underground, although he did speculate whether the pouch was an adaptation to the “long drought of the Australian rivers”). See EthyFish.org for more details. (See ETYFish); gallegensis: -ensis, Latin suffix denoting place: Río Gallegos drainage, southeastern Argentina, where type locality (Río Turbios) is situated. (See ETYFish).
Environment: milieu / climate zone / depth range / distribution range
Ecology
Freshwater; brackish; demersal; unknown. Temperate
Distribution
Countries | FAO areas | Ecosystems | Occurrences | Point map | Introductions | Faunafri
South America
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Firpo Lacoste, F., L. Fernández and C. Scioscia, 2021. On an unknown lamprey holotype (Petromyzon macrostomus Burmeister 1868) and the genus Exomegas Gill 1883 from South America. J. Fish Biol. 99(4):1507-1512. (Ref. 125540)
IUCN Red List Status (Ref. 125652)
Threat to humans
Harmless
Human uses
More information
Countries
FAO areas
Ecosystems
Occurrences
Introductions
Stocks
Ecology
Diet
Food items
Food consumption
Ration
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningSpawning aggregationFecundityEggsEgg development
Age/Size
Growth
Length-weight
Length-length
Length-frequencies
Morphometrics
Morphology
Larvae
Larval dynamics
Recruitment
Abundance
BRUVS
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Tools
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Internet sources
Estimates based on models
Phylogenetic diversity index (Ref.
82805): PD
50 = No PD50 data [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 BS (Ref.
93245).
Trophic level (Ref.
69278): 4.5 ±0.8 se; based on size and trophs of closest relatives
Resilience
Fishing Vulnerability (Ref.
59153): Moderate vulnerability (43 of 100) .
Climate Vulnerability (Ref.
125649): (0 of 100) .