Comment on the proposed suppression of Elipesurus spinicauda Schomburgk (Pisces). Z.N.(S.) 1825
1969; International Trust for Zoological Nomenclature; Volume: 25; Linguagem: Inglês
10.5962/bhl.part.23973
ISSN2057-0570
Autores Tópico(s)Identification and Quantification in Food
ResumoCastex (1968) tias petitioned thiat tlie names Elipesnrus Schomburgk, 1843, and E. ipm/fflwrfo Schomburgk, 1843, based on a South American freshwater elasmobranch, be suppressed for the purposes of the Law of Priority and placed on the Official Index of Rejected and Invalid Names in Zoology.This request stems from the belief that Elipesnrus spinicanda is identical with Polamotrygon brachywus Gijnther, 1880 (Castex, 1966b), a species otherwise unknown from the Amazon basin; application of the senior synonym would substitute a little-known generic name for the widely used and familiar Potamotrygon Garman, 1877, that enters significantly into physiological literature.Garman (1913) and Castex (1966a) recognized three genera of South American freshwater rays: Elipeswus, known from Schomburgk's account and figure of a specimen 18 inches long from Rio Branco, Fort San Joaqium (sic; Joachim, p. 130], Brazil; Disceus Garman (1877), monotypic, Amazonian; and Potamotrygon Garman (1877), with several species, ranging from Colombia to Argentina.Elipeswus spinicanda Schomburgk, 1843, was rather well illustrated and described, has a precise type locality, and should be placeable.Castex's studies of large numbers of South American rays have been centered in the southern waters of the continent, outside the range of Disceus thayeri Garman.My limited field experience with this group, as participant in an American Museum of Natural History expedition in 1 964, was in the Rio Guapore, [-Rio Itenez] of the Madeira system, along the border between Bolivia and Brazil.There I took three species of stingrays, two of Potamotrygon and Disceus thayeri.The latter is common, attains a large size, and undergoes notable change with age.My findings, being published elsewhere, interpret Schomburgk's Elipesnrus spinicanda as a mutilated, moderate-sized individual of the same species that was named Trygon strogylopterus Schomburgk, 1843, in the same work, on the basis of a small juvenile.Under the prerogative of first reviser I select the name spinicanda.Both nominal species are the same as Disceus thayeri Garman (1913), which name therefore becomes a subjective junior synonym of Elipesnrus spinicanda Schomburgk.Crucial to the association of E. spinicanda with thayeri rather than with a species of Potamotrygon are the great development (with age) of strong dermal spines, irregularly disposed about the base of the tail ; the complete coverage of the pelvic fins by the pectoral disk; the absence of an anterior median prominence on the disk; and the slender and abruptly tapering tail, which lacks the poison spine -surely from mutilation.Schomburgk's figure of Trygon strogylopterus well illustrates the slender tail and the proximity of the poison spine to the disk, distinctive features of Elipesurus (= Disceus).This placement of Elipesurus removes it from competition with Potamotrygon, which may be retained for the larger, better-known genus of the Potamotrygoninae (family Dasyatidae).I agree with Garman (1877 : 210) and with Castex (1968) that Paratrygon Dumeril, 1865, based on the Aiereba Marcgrave, 1648. is best considered a nomen dubium.In view of the above I believe it inadvisable for the International Commission on Zoological Nomenclature to support items 8(1 ), 8(4), and 8(5), dealing with Elipesurus spinicanda, of Castex's request. 1 support items 8(2), 8(3), and 8(6) dealing with Potamotrygon, P. hystri.x,and the Potamotrygonidae, but note that the gender of Potamotrygon is feminine. References
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