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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); australis: Latin for southern, referring to South Australia, type locality. (See ETYFish).
More on author: Gray.
Issue
Neira et al., 1988 (Ref. 115329) showed that ammocoetes of an Argentinian population were morphologically distinct from ammocoetes of both Chilean and Australasian (mainland Australia, Tasmania, and New Zealand) populations of the species. Additionally, they stated that adults from Argentina and from South Georgia Island had the cloaca positioned well posterior to the origin of the second dorsal fin rather than aligned immediately under its origin as in Chilean and Australasian populations. Perhaps, therefore, the Argentinian and South Georgian Island population represents a distinct species and this question merits closer scrutiny.
Environment: milieu / climate zone / depth range / distribution range
Ecologia
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