Freshwater Prawns of the Genus Macrobrachium (decapoda, Palaemonidae) with Abbreviated Development from the Papaloapan River Basin, Veracruz, Mexico: Distribution and New Species

Abstract In the Papaloapan River two freshwater prawns with abbreviated development have been recorded: Macrobrachium villalobosi (a stygobitic species) and Macrobrachium totonacum (an epigeal species). In this paper we describe four new species from this genus, and the distribution of these six species along the river basin. M. oaxacae nov. sp. occurs in the River La Junta, and together with M. cosolapaense nov. sp. is geographically close to the stygobitic species and M. totonacum, but differs from these in the following aspects: pigmentation, the number of rostral spines, and the relative proportions of the articles of the second pereiopod, of appendix masculina and appendix interna, and the number of spines on the appendix masculina. Macrobrachium mazatecum nov. sp. lives in two streams in Veracruz: the first close to Tierra Blanca Veracruz and the second on the Zapotal Veracruz near Mpio. Lerdo de Tejada. This species was also recorded in two springs near Valle Nacional Oaxaca, and differs from M. oaxacae nov. sp. and M. cosolapaense nov. sp. in the number of rostral spines, and the relative proportions on the articles of second pereiopod, of appendix masculina and appendix interna, and of the spines on the appendix masculina. Finally, Macrobrachium jacatepecense nov. sp. occurs only in a spring near Jacatepec, Oaxaca. This species differs from the other species in the relative proportions of the articles of the second pereiopod: however, it is very close to Macrobrachium oaxacae nov. sp. in the number of rostral spines, but based on the geographical distribution of both species and other features, it is clearly a different species. In this Papaloapan River basin, the distribution of this complex of species is very limited, because the various populations live in very restricted areas associated with springs or small streams, and without direct interconnections. All these new species are comparable with the epigeal Macrobrachium species in the southeast of Mexico that have abbreviated larval development.