Fecundity, embryo size and embryo loss in the estuarine shrimp Salmoneus carvachoi Anker, 2007 (Crustacea: Alpheidae) from a tidal mudflat in northeastern Brazil

Studies on fecundity and embryo size have been frequently used to infer about the reproductive potential, embryogenesis, and the energy investment in embryo production in crustaceans. These parameters are relevant to the knowledge of life-history and diversity of reproductive strategies developed by this group. This study addressed the embryo production by the estuarine shrimp Salmoneus carvachoiAnker, 2007, a poorly known caridean shrimp. We investigated whether there was (1) a correlation between fecundity and carapace length, (2) an increase in embryo volume along the embryonic development, and (3) loss of embryos along development. In addition, we investigated whether the esternite length and height and width of the pleura of the second abdominal somite were good predictors of fecundity. A total of 53 embryo-carrying individuals were collected in December 2016 and February 2017 in a tidal mudflat from the estuary of the Paripe River, Ilha de Itamaracá, Pernambuco, Brazil. The carapace length ranged from 3.23 to 4.64 mm (3.78 ± 0.26 mm). Among those, 25 individuals had embryos in initial stage, 5 in intermediate stage and 15 in final stage. Fecundity ranged from 14 to 67 (33.65 ± 12.51 embryos) and was weakly correlated with carapace length. However, fecundity was strongly correlated with the width of the second sternite and width of the pleura of the second abdominal somite. Embryo volume increased markedly (93%) from the initial to the final stage of development. This increase might be due to water uptake to facilitate the membrane rupture at the onset of larvae hatching. There was significant loss of embryos only between the initial and intermediate stage. Future studies on the embryo production by other species of Salmoneus Holthuis, 1955 are necessary to understand and compare these aspects of reproductive biology.

Fecundity, embryo size and embryo loss in the estuarine shrimp Salmoneus carvachoi Anker, 2007 (Crustacea: Alpheidae) from a tidal mudflat in northeastern Brazil

Studies on fecundity and embryo size have been frequently used to infer about the reproductive potential, embryogenesis, and the energy investment in embryo production in crustaceans. These parameters are relevant to the knowledge of life-history and diversity of reproductive strategies developed by this group. This study addressed the embryo production by the estuarine shrimp Salmoneus carvachoiAnker, 2007, a poorly known caridean shrimp. We investigated whether there was (1) a correlation between fecundity and carapace length, (2) an increase in embryo volume along the embryonic development, and (3) loss of embryos along development. In addition, we investigated whether the esternite length and height and width of the pleura of the second abdominal somite were good predictors of fecundity. A total of 53 embryo-carrying individuals were collected in December 2016 and February 2017 in a tidal mudflat from the estuary of the Paripe River, Ilha de Itamaracá, Pernambuco, Brazil. The carapace length ranged from 3.23 to 4.64 mm (3.78 ± 0.26 mm). Among those, 25 individuals had embryos in initial stage, 5 in intermediate stage and 15 in final stage. Fecundity ranged from 14 to 67 (33.65 ± 12.51 embryos) and was weakly correlated with carapace length. However, fecundity was strongly correlated with the width of the second sternite and width of the pleura of the second abdominal somite. Embryo volume increased markedly (93%) from the initial to the final stage of development. This increase might be due to water uptake to facilitate the membrane rupture at the onset of larvae hatching. There was significant loss of embryos only between the initial and intermediate stage. Future studies on the embryo production by other species of Salmoneus Holthuis, 1955 are necessary to understand and compare these aspects of reproductive biology.(AU)

New and additional records of Salmoneus Holthuis, 1955 (Decapoda, Caridea, Alpheidae) from Brazil, with a key to the southern Atlantic species

Two species of the alpheid shrimp genus Salmoneus Holthuis, 1955, are reported from shallow waters of São Sebastião (SP), southeastern Brazil. Salmoneus depressus Anker, 2011 is recorded for the first time in Brazil and the southwestern Atlantic; this species was previously known only from the Caribbean region. Salmoneus ortmanni (Rankin, 1898) is recorded for the first time in southern Brazil (23°S), being previously known in Brazilian waters from a single confirmed record from Atol das Rocas (03°S), with older records referring to Salmoneus carvachoi Anker, 2007. A hitherto unknown morphological variation in S. depressus is discussed and illustrated. Both species are shown in colour to facilitate their identification in the field. A key to the southern Atlantic species of Salmoneus is also provided.

New and additional records of Salmoneus Holthuis, 1955 (Decapoda, Caridea, Alpheidae) from Brazil, with a key to the southern Atlantic species

Two species of the alpheid shrimp genus Salmoneus Holthuis, 1955, are reported from shallow waters of São Sebastião (SP), southeastern Brazil. Salmoneus depressus Anker, 2011 is recorded for the first time in Brazil and the southwestern Atlantic; this species was previously known only from the Caribbean region. Salmoneus ortmanni (Rankin, 1898) is recorded for the first time in southern Brazil (23°S), being previously known in Brazilian waters from a single confirmed record from Atol das Rocas (03°S), with older records referring to Salmoneus carvachoi Anker, 2007. A hitherto unknown morphological variation in S. depressus is discussed and illustrated. Both species are shown in colour to facilitate their identification in the field. A key to the southern Atlantic species of Salmoneus is also provided.(AU)