title: Ocurrence of male morphotypes of Macrobrachium amazonicum (Caridea, Palaemonidae) in a population with an entirely freshwater life cycle.
abstract: This study records, for the first time, the occurrence of all four male morphotypes in a population of Macrobrachium amazonicum from a continental environment, with an entirely freshwater life cycle. The specimens studied came from the Tietê River, state of São Paulo, Brazil, and were collected in a lotic environment downstream from Ibitinga Dam. This population was compared with other continental populations, including a population from the dam itself, collected in a previous study. Four samples of 30 minutes were taken monthly, using a trap, from January to April 2011. Each male specimen was measured with respect to seven body dimensions as follows: carapace length (CL), right cheliped length (RCL), dactyl length (DCL), propodus length (PPL), carpus length (CRL), merus length (ML) and ischium length (IL). The relative growth was analyzed based on the change in growth patterns of certain body parts in relation to the independent variable CL. The four male morphotypes proposed for the species were found using morphological and morphometric analyses. Different biological characteristics were found between the populations studied. The male population of the lake of Ibitinga and from Pantanal presented mean sizes and number of morphotypes lower than the population studied here. These differences seem to be closely related to ecological characteristics of the environments inhabited by these populations. Our results supported the hypothesis that coastal and continental populations of M. amazonicum belong to the same species.
authors: Laboratório de Biologia de Camarões Marinhos e de Água Doce - LABCAM, Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Bauru, SP, Brazil.
authors: J A F
authors: JA
authors: Pantaleão
authors: Laboratório de Carcinologia, Centro de Ciências Biológicas e da Saúde - CCBS, Universidade Federal de Sergipe - UFS, São Cristóvão, SE, Brazil.
authors: G L
authors: GL
authors: Hirose
authors: Laboratório de Biologia de Camarões Marinhos e de Água Doce - LABCAM, Departamento de Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista "Júlio de Mesquita Filho" - UNESP, Bauru, SP, Brazil.
authors: R C
authors: RC
authors: Costa
mesh_terms: D000818:Animals; D001938:Brazil; D005260:Female; D005618:Fresh Water; D008018:Life Cycle Stages / Q000502:physiology; D008297:Male; D033541:Palaemonidae / Q000033:anatomy & histology* / Q000145:classification* / Q000502:physiology; D012098:Reproduction / Q000502:physiology