Packard's and Pearse's Species of Branchinecta: Analysis of a Nomenclatural Involvement

Abstract

Because of confusion over the correct specific names, the following species have been redescribed with taxonomically serviceable drawings of both sexes: Branchinecta coloradensis Packard, 1874, B. lindahli Packard, 1883, and B. packardi Pearse, 1912. Type specimens of Packard's two species are nonexistent; neotypes have been deposited in the U. S. National Museum. The specific identity of B. coloradensis Pack., 1874 cannot be established from the original description. Packard's redescription of 1883 is invalidated by contradictions between it and the first description. Shantz (1905) redescribed Packard's species, his specimens certainly being identical with those of Packard's second description. He assumed that Packard's two descriptions were of the same species, which may or may not be the case, but by his redescription validated the name coloradensis for the species corresponding to Packard's second description. As the first reviser of Packard's obscure and conflicting descriptions, Shantz's identification of the species, and assignment of the specific name, have priority over later revisions. B. shantzi Mackin, 1952 is a junior synonym of B. coloradensis Pack., as reviewed by Shantz, 1905. B. lindahli Packard, 1883 was also insufficiently described. Shantz's revision (1905) adequately described as B. lindahli a species which is most likely identical with that of Packard. As the first reviser of Packard's deficient description, Shantz's identification of the species and his allocation of the specific name are entitled to recognition as valid. There is no positive evidence that B. coloradensis Pack., 1874 is identical with the B, lindahli of Shantz's redescription, therefore the B. coloradensis Pack. of Mackin, 1952 must be considered a junior synonym of B. lindahli Pack., as revised by Shantz, 1905. B. packardi Pearse, 1912 is a valid species. Comparison of specimens with Packard's description of B. lindahli fails to disclose any certain correspondences in the specific characters. Consequently, the B. lindahli Pack. of Mackin's revision (1952) is a junior synonym of B. packardi Pearse. In recent years uncertainty has arisen concerning the species of fairy shrimp to be identified as Branchinecta coloradensis Packard, 1874, B. lindahli Packard, 1883, and B. packardi Pearse, 1912. Throughout this paper these specific nanmes will be used in conformity with the usage in the keys of Pearse (1918), Creaser (1935), and with the descriptions of Shantz (1905). It is hoped that an analysis of Packard's work, accompanied by more exact illustrations of the disputed species, will enable a definite decision as to the correct name of each species which will be in agreement with the International Code of Zoological Nomenclature. The primary responsibility for the confusions must be attributed to A. S. Packard, whose descriptions are not only deficient in requisite taxonomic detail, but are so filled with errors, contradictions, and 1 This study was supported by Grant No. G 17604 from the National Science Foundation.