Abbreviated larval development of Macrobrachium inpa Kensley and Walker, 1982 (Crustacea: Decapoda: Palaemonidae) from an Amazon Basin forest stream, Brazil, reared in the laboratory

Th is paper brings the description and illustrations of the abbreviated larval development of the Amazonian freshwater palaemonid shrimp, Macrobrachium inpa Kensley and Walker, 1982. Th e study was based on ovigerous females (mean total body length of 27.0 ± 1.64 mm) collected in a small forest stream in the Reserva Florestal Ducke, near Manaus, Brazil, of which four released their larvae in the laboratory. Th e females carried 8 to 19 eliptical (2.39 ± 0.10 X 1.67 ± 0.08 mm), yolk-rich eggs. Th e larval period consists of three benthic, lecithotrophic larval stages, and lasts 10–11 days. Th e newly-hatched larvae bear very advanced morphological features such as antenna with several marginal plumose seta on scaphocerite and long, multiarticulated fl agellum; fully developed, functional uniramous pereiopods 3–5 (walking legs) and biramous pleopods. Th e morphology of the carapace, all appendages of the cephalothorax and pleon, and the tail fan are described in detail and illustrated. Th e larval form was considered to be a decapodid because of the benthic behavior and due to the fact that functional walking legs and pleopods are the main structures for displacement and propulsion. Th e larval development of M. inpa is compared with those of the so-called “continental” group of the caridean shrimps from the Amazon River basin. orIgInal artIcle This article is part of the special series offered by the Brazilian Crustacean Society in honor to Nilton José Hebling in recognition of his dedication and contributions to the development of carcinology in Brazil.