RESUMO
Taxonomic rearrangements were recently proposed for some members of Portunus Weber and Cronius Stimpson, including the re-elevation of the status of the subgenus Achelous De Haan to accommodate 21 American species. In the present study the first zoea of Achelous spinimanus, type species of the genus, A. gibbesii and Portunus sayi were obtained from laboratory-hatched specimens. The morphology of the first zoeal stage of A. spinimanus is described and illustrated for the first time. Those of A. gibbesii and P. sayi are redescribed in detail using standard terminology and compared with previous unpublished descriptions. Differences are listed and remarks from a comparative analysis of available descriptions of other portunid genera and species with a known first zoeal stage are furnished. The larval morphology pattern observed in the studied species corroborates a previous hypothesis on the phylogeny of the group.
Assuntos
Braquiúros , Animais , Decápodes , Laboratórios , Larva , FilogeniaRESUMO
The aims of this study were to describe and illustrate the early larval stages of the snapping shrimp Alpheus brasileiro Anker, 2012 and to review the larval morphology (Zoea I) of the genus Alpheus Fabricius, 1798. Larvae were obtained from two females with embryos collected in an intertidal estuary in Cananéia, São Paulo state, Brazil. The published descriptions of all available Alpheus zoea I (only 14 spp., 4.7%) were used for a comparison of larval morphology. The zoeae I of Alpheus species are very similar, but A. brasileiro can be separated from the other studied species by the following set of characteristics: antennal scale 5-segmented with 11 plumose setae and 2 simple setae; coxal endite of maxillule with 3 simple setae and 2 sparsely plumose setae; and coxal endite of maxilla with 1 simple seta and 1 sparsely plumose seta. The description of early larval development of A. brasileiro indicates consistent characteristics, which, when analyzed along with other morphological, molecular, and biogeographical aspects, can help to elucidate the complex phylogenetic relationships between the species in the group. However, this is the first zoeal description of a member of Alpheus armillatus species complex and it therefore does not permit a comparison. Only with new additional descriptions we will be able to generate a clearer scenario in this field due the high similarity among the species.
Assuntos
Decápodes , Animais , Brasil , Feminino , Larva , FilogeniaRESUMO
The morphology of the first zoeal stage of Periclimenes paivai Chace is described and illustrated for the first time. Larvae were obtained from three females with embryos, caught in the type locality (Cananéia, São Paulo state, Brazil). The morphological characters are detailed and compared with all previous descriptions of larvae in the genus (P. amethysteus, P. brevicarpalis, P. diversipes, P. pandionis, P. sagittifer and P. soror). The zoeae I of Periclimenes species are very similar, but P. paivai can be separated from the other six species by means of five characteristics: 8 plumose setae on the inner margin of the antennal scale, one spine on the endopod of the maxillule, one cuspidate seta on the basal endite of the maxilulle, one plumose seta on the single coxal endite of the maxilla, and one plumose seta on the endopod of the maxilla. Remarks from a comparative analysis of available descriptions of the genus are furnished.