MACROBRACHIUM VICCONI, NEW SPECIES, A FRESH-WATER SHRIMP FROM A RAIN FOREST IN SOUTHEAST MEXICO, AND COMPARISON WITH CONGENERS (DECAPODA: PALAEMONIDAE)

Macrobrachium vicconi, new species, from a rain forest of southeastern Mexico is described. It is similar to Macrobrachium quelchi and Macrobrachium atabapense in total length, partially abbreviated larval development, and cornea not reduced. Macrobrachium vicconi differs from those species in the size-ratio of the articles of the legs, the spinous ornamentation, and the length of the second pereiopods. Macrobrachium vicconi is more closely related to the inland South American complex of Macrobrachium in bearing few large eggs, than to other epigean species described in the genus from the Americas. The new species is the first epigean species of Macrobrachium with partially abbreviated larval development described from North America, Central America, and the Caribbean.