Morphology of the early larval stages of Lysmata ankeri Rhyne & Lin, 2006 and Lysmata bahia Rhyne & Lin, 2006 (Caridea: Lysmatidae) and a review of the larval morphology of the early Lysmata stages.

The early larval stages of the shrimps Lysmata ankeri and L. bahia were described, illustrated, and compared among other Lysmata species, providing important information on post-embryonic development and insights into its evolutionary history. Ovigerous specimens of L. ankeri and L. bahia were sampled from southeastern and northeastern Brazilian coast, respectively. For L. ankeri and L. bahia, five and three larval stages were obtained, respectively. Unique features were observed for L. ankeri and L. bahia larvae, and some characteristics may differ only for L. ankeri and L. bahia, which were not observed in the other species analyzed, such as: presence of a pair of simple setae on the third pleonal somite in zoea I and number of setae on the uropod exopod greater than 11. Moreover, several other features are similar between species from the diferent clades of the Lysmata-Exhippolysmata complex, making it possible to identify the early stages of Lysmata larvae. However, future studies will be essential to confirm or not the existence of some phylogenetic patterns and their relevance and other larval characters for better understanding the evolutionary history of this group.

Morphology of the early larval stages of Lysmata lipkei Okuno amp; Fiedler, 2010 (Caridea: Lysmatidae): an invasive shrimp in the Western Atlantic.

Considering the importance of establishing different approaches to the early detection of invasive species, the present study aimed to describe and illustrate the morphology of the early larval stages of the shrimp Lysmata lipkei, an invasive species in the Western Atlantic. Additionally, we did a morphological comparison and a review of the other Lysmata species from the Western Atlantic Ocean with a known larvae description. The larvae used in this study were obtained by the maintenance, under laboratory conditions, of ovigerous hermaphrodites of L. lipkei, collected in the wild. Then, larvae were dissected under a stereo microscope and illustrated using a microscope equipped with a camera lucida. The first three larval stages (zoeae) of L. lipkei were illustrated, described, and compared to other species of Lysmata previously described of the Western Atlantic. Some features of the larval morphology of L. lipkei are very similar when compared to other Lysmata species with previous larval descriptions, such as a rostrum long and simple, the eyes stalked with a long peduncle from the second zoeae, one pterygostomian spine and several denticles along the anterior ventral margin of the carapace, similarities in the segmentation of the maxillipeds, and the presence of dorsolateral spines on the posterior margin of the 5th pleomere, among other features. Also, unique features were observed for L. lipkei, such as differences in the setation of some structures, including the antennule, antenna, maxillule, and maxillipeds. Using the morphological descriptions, we expect to identify species from the plankton, especially invaders, that might be present in the Western Atlantic, as well as assist in several areas in which the larval morphology is relevant.

Genome Sequence Analysis of CsRV1: A Pathogenic Reovirus that Infects the Blue Crab Callinectes sapidus Across Its Trans-Hemispheric Range.

The blue crab, Callinectes sapidus Rathbun, 1896, which is a commercially important trophic link in coastal ecosystems of the western Atlantic, is infected in both North and South America by C. sapidus Reovirus 1 (CsRV1), a double stranded RNA virus. The 12 genome segments of a North American strain of CsRV1 were sequenced using Ion Torrent technology. Putative functions could be assigned for 3 of the 13 proteins encoded in the genome, based on their similarity to proteins encoded in other reovirus genomes. Comparison of the CsRV1 RNA-dependent RNA polymerase (RdRP) sequence to genomes of other crab-infecting reoviruses shows that it is similar to the mud crab reovirus found in Scylla serrata and WX-2012 in Eriocheir sinensis, Chinese mitten crab, and supports the idea that there is a distinct "Crabreo" genus, different from Seadornavirus and Cardoreovirus, the two closest genera in the Reoviridae. A region of 98% nucleotide sequence identity between CsRV1 and the only available sequence of the P virus of Macropipus depurator suggests that these two viruses may be closely related. An 860 nucleotide region of the CsRV1 RdRP gene was amplified and sequenced from 15 infected crabs collected from across the geographic range of C. sapidus. Pairwise analysis of predicted protein sequences shows that CsRV1 strains in Brazil can be distinguished from those in North America based on conserved residues in this gene. The sequencing, annotation, and preliminary population metrics of the genome of CsRV1 should facilitate additional studies in diverse disciplines, including structure-function relationships of reovirus proteins, investigations into the evolution of the Reoviridae, and biogeographic research on the connectivity of C. sapidus populations across the Northern and Southern hemispheres.