ABSTRACT
The genus Hyalella is endemic to the North and South America. There are currently 14 species described in North America and the Caribbean. For a long time, it had been assumed that different populations of these animals represented a single species, Hyalella azteca (Saussure, 1858). However, molecular analyses have demonstrated H. azteca sensu lato to be a complex of multiple species, so some species that occur in the United States have been mistakenly identified. Our aim in this paper was to describe a new species of Hyalella, found in Oklahoma, USA. The new species can be differentiated from the others, mainly because it presents serrated setae in the maxilla 2, because it does not have flanges on the surface of the body, presents the palm of the gnathopod 2 of the same size as the distal-posterior margin of the propodus, by shape and number of setae on the uropod 3 and telson. The description of this new species of Hyalella increases to 15 the number of species of the genus for the USA. It is important to understand the diversity of Hyalella with consideration of their possible role as bioindicators of environmental quality, and further consideration of their conservation status, and especially for species known from a single spring.
Subject(s)
Amphipoda , Animals , OklahomaABSTRACT
Two new species of Hyalella from Brazil are described. Hyalella veredae sp. n. shows the following characters: eyes reduced or absent in some specimens; antenna 1 and antenna 2 of similar size, and a curved seta on the inner ramus of male uropod 1. Hyalella formosa sp. n. is characterized by the absence of eyes, antenna 1 longer than antenna 2 and a curved seta on the inner ramus of male uropod 1. The species were found on caves located in two private properties, both under the impact of agricultural activities, which demonstrates a potential threat to these subterranean environments.
Subject(s)
Amphipoda/classification , Amphipoda/anatomy & histology , Animal Distribution , Animal Structures/anatomy & histology , Animals , Brazil , Ecosystem , Female , MaleABSTRACT
The freshwater crustaceans from the order Amphipoda occur mainly in cold and temperate climates. However, in the tropics, these animals can be more abundant in subterranean environments, where the temperatures are milder than in surface. Despite being accepted that the number of species of freshwater amphipods in South America is lower when compared to other regions, recent descriptions have shown that its diversity is certainly underestimated. In this study, a new species of the genus Hyalella is described for Brazil, the fourth troglobiotic species of Hyalella for the country and the sixth in the world. The new species was found on the epikarst of a cave in São Paulo state, Southeastern Brazil. Besides, the new species shows typical characteristics from organisms adapted to the subterranean environments, a pattern also observed in the other troglobiotic species of the genus.
