Mariana Terossi

Interpopulation Comparison of Reproduction of the Atlantic Shrimp Hippolyte obliquimanus (Caridea: Hippolytidae)

Abstract The genus Hippolyte is represented by typically small shrimps with intriguing mechanisms of reproduction. In order to study possible variability in reproductive aspects among different populations, we conducted an exhaustive comparative study of H. obliquimanus from South (Brazil) and Central American (Costa Rica) waters. The study focuses on fecundity and reproductive output. Mean size of ovigerous females was significantly larger, and both mean reproductive output and mean fecundity were significantly higher in specimens from Costa Rica then in those collected in Brazil. Embryo volume was significantly smaller in the Costa Rican population, and in both populations embryos doubled their volume during embryogenesis. We discuss and compare our findings with the information available regarding H. obliquimanus and other hippolytid shrimp. The reproductive traits of both populations of H. obliquimanus show some important differences which may reflect adaptations to local environmental conditions, demonstrating a high plasticity of reproductive features of the species in Brazilian and Costa Rican waters.

Sexual ratio, reproductive period and seasonal variation of the gonochoric shrimp Hippolyte obliquimanus (Caridea: Hippolytidae)

Abstract Hippolyte obliquimanus is a small, gonochoric shrimp found in algal substrates along the western Atlantic coast of Brazil, particularly in association with seaweed of the genus Sargassum. We studied population features (sexual ratio, reproductive period and temporal distribution) of H. obliquimanus in southeastern Brazil, including its relationships with the seasonality of banks of this alga. Specimens were collected at two-monthly intervals from March 2005 to January 2006, in Ubatuba Bay. The sex of individuals was checked, and the carapace length measured. In total, 668 individuals were collected: 211 males (0.70–2.50 mm carapace length), 341 non-ovigerous females (0.55–2.90 mm), and 116 ovigerous females (1.55–3.20 mm). Hippolyte obliquimanus showed seasonal–continuous reproduction and variable continuous recruitment. The highest number of animals (75%) was collected in fall–winter. The percentages of ovigerous females/total females (fall–winter: 27%; spring–summer: 26%) and the sexual ratio (fall–winter: 31%; spring–summer: 32%) were practically equal in both periods. The sexual ratio showed a predominance of females in almost all size classes, and we detected a new sex ratio pattern for this species. The seasonal variation in the number of individuals can be related to its migration to deeper areas, due to the decrease in the abundance of Sargassum sp. in shallower waters in spring–summer.

Pattern of shell occupation by the hermit crab Pagurus exilis (Anomura, Paguridae) on the northern coast of São Paulo State, Brazil

The purpose of this study was to determine the shell occupation pattern of Pagurus exilis using the percentage of shell types that were occupied and the morphometric relationship between hermits and occupied shells. Specimens were collected monthly from July 2001 to June 2003. A total of 1737 individuals were collected, occupying 19 gastropod shell species. Buccinanops gradatum (82%) was the most occupied shell, followed by Natica isabelleana (6.4%), Stramonita haemastoma (3.2%), and Cymatium parthenopeum (2.2%). There was a differential shell utilization pattern between sexes; males occupied larger and heavier shells while the non‐ovigerous females occupied the lightest ones. Pagurus exilis occupied more bare shells instead of incrusted ones. Buccinanops gradatum was the most occupied shell species as a function of its availability in the survey, and this occupation is strongly associated with the higher internal volume presented by these shells.

Morphological and genetic variability in Hippolyte Obliquimanus Dana, 1852 (Decapoda, Caridea, Hippolytidae) from Brazil and the Caribbean Sea

Hippolyte obliquimanus is a marine shrimp reported from the Caribbean Sea and Brazil. The literature provides indications for morphological variation between populations from those regions and the species has a troubled taxonomic history. The aims of this study were to analyse morphological and genetic variation in the populations of H. obliquimanus from Brazil and the Caribbean Sea and to verify if those might support separation of H. obliquimanus into two or more species. This hypothesis was tested with the analysis of morphological and genetic data (mitochondrial gene 16S and the barcode region Cytochrome Oxidase I). The material analysed was obtained from samples and from loans of zoological collections. The rostrum as well as pereiopods 3, 4, and 5 were the adult morphological characters that showed variation, but this occurred in samples from both regions, Brazil and the Caribbean Sea. The sequences of the 16S gene were identical among all specimens analysed. There was, however, variation among the sequences of the barcoding gene COI (<2.0%); this divergence separated the specimens into two groups (Brazil versus the Caribbean) and these groups did not share haplotypes. In conclusion, specimens from the regions analysed showed both morphological and genetic variation, but these did not support the separation of H. obliquimanus into two or more species.

Morphology and DNA analyses reveal a new cryptic snapping shrimp of the Alpheus heterochaelis Say, 1818 (Decapoda: Alpheidae) species complex from the western Atlantic

ABSTRACT Previous evidence regarding morphology led us to examine an exhaustive set of specimens assigned to Alpheus heterochaelis Say, 1818 and closely allied species, in order to test for the existence of possible cryptic taxa. The analysis of material assignable to this species from the states of Pará, Bahia and São Paulo in Brazil, and from Venezuela and Colombia revealed minor morphological differences between these specimens and others that could be confidently identified as A. heterochaelis from the eastern USA coast and the Gulf of Mexico, such as the absence of spiniform setae on the ischium of the fifth pereiopods (vs present in A. heterochaelis s.s.). Additionally, genetic analysis using the ribosomal 16S subunit also indicated levels of genetic difference supporting the existence of a cryptic species and revealing that A. heterochaelis is, in fact, a species complex. Thus, a new species, A. petronioi n. sp. is described and illustrated for the material from northern South America and Brazil. The new species is also compared with other, similar species of Alpheus Fabricius, 1798 in terms of morphology and DNA sequences in a phylogenetic context.

Revision of the larval morphology (Zoea I) of the family Hippolytidae (Decapoda, Caridea), with a description of the first stage of the shrimp Hippolyte obliquimanus Dana, 1852

Resumen del poster presentado al 2nd International Conference on Food Digestion celebrado en Madrid (Espana) del 6 al 8 de marzo de 2013.Trabajo presentado a las I Jornadas Cientificas del CIAL celebradas el 5 de junio de 2014 en Madrid.The aim of this study was to summarize the available data on larval morphology of the first zoea of the family Hippolytidae and describe the first zoeal stage of H. obliquimanus from two geographically distinct populations, Brazilian and Caribbean in order to discuss interand intraspecific variability. Ovigerous females of Hippolyte obliquimanus were collected at Cahuita (Limon, Costa Rica) and at Ubatuba (Sao Paulo, Brazil). We compiled the published descriptions of all available hippolytid Zoea I (66 spp., 21%), and all zoeae share several characteristics. However, such morphological features cannot be used to distinguish the first zoeae of Hippolytidae from other caridean larvae. Historically, the presence of an exopodal seta at the maxillule and the absence of the anal spine/papilla have been considered as characteristic for the Zoea I of the genus Hippolyte. The results of our revision, however, did not support these conclusions: although H. obliquimanus showed an exopodal seta at the maxillule, four congeners did not bear such structure; moreover, H. obliquimanus as well as one other congener have an anal spine/papilla. All morphological characters observed in the first zoeal stage of H. obliquimanus are shared with others species of the family Hippolytidae. Intraspecific variability in Hippolyte obliquimanus was detected in one morphological aspect: the first zoea had four denticles on the ventral margin of the carapace in the Brazilian population, while specimens from the Costa Rican population had three.Trabajo presentado en el VIII Congresso Brasileiro de Crustaceos (Transicoes evolutivascrustaceos no mar, na agua doce e na terra), celebrado en Bonito (Brasil) del 9 al 12 de noviembre de 2014.

A novel spermatozoan ultrastructure in the shrimp Hippolyte obliquimanus Dana, 1852 (Decapoda: Caridea: Hippolytidae)

The aim of this study was to describe and illustrate the morphology of the spermatozoon of the Western Atlantic shrimp, Hippolyte obliquimanus. Individuals were sampled from Itaguá Beach (Ubatuba, southern Brazil). The male reproductive system was dissected and morphological analysis was undertaken using a stereomicroscope, a light microscope, and transmission electron and scanning electron microscopes. When viewed from the nuclear or acrosomal poles, each spermatozoon has many translucent radiating arms (about 20) from a denser cell body, while laterally the cell body and arms resemble a “cnidarian medusa”, with all the arms projecting away from the bell-like cell body. This sperm morphology is distinct from the “thumbtack”-shaped spermatozoa observed in the majority of carideans but has similarities to the spermatozoa of Rhynchocinetes spp. The morphology of sperm of several species of the genus Hippolyte resembles the spermatozoon of H. obliquimanus with the presence of posterior nuclear arms, but it is necessary to study other Hippolyte species to place these arms in the context of the genus.

Checklist of decapods (Crustacea) from the coast of the São Paulo state (Brazil) supported by integrative molecular and morphological data: I. Infraorder Caridea: families Hippolytidae, Lysmatidae, Ogyrididae, Processidae and Thoridae

The current checklist is the result of a long-term multidisciplinary project which combined molecular techniques (mitochondrial DNA markers) and morphological analyses of adult specimens for an accurate and detailed identification of the total biodiversity of decapod crustaceans from marine and coastal (including estuaries) environments of São Paulo State (Brazil). This is the first of a series of reports and providing a checklist of caridean shrimps of the families Hippolytidae (5 spp.), Lysmatidae (6 spp.), Ogyrididae (2 spp.), Processidae (5 spp.) and Thoridae (1 sp.). We collected material of 13 species out of 19 recorded, with sequences of cytochrome oxidase subunit I - barcode region and 16S generated from 10 species. The previous record of Lysmata cf. intermedia for São Paulo is actually L. jundalini, as the first record in São Paulo/South Atlantic waters. The molecular data were helpful to confirm the identification of some species, as the occurrence of L. wurdemanni which is confirmed in the South Atlantic Ocean based on morphological, color pattern and molecular data.

First zoeal stage of Processidae (Decapoda, Caridea): review and new descriptions of Ambidexter symmetricus Manning and Chace 1971 and Processa fimbriata Manning and Chace 1971

This study reviews the morphology of the first zoeal stage of the pantropical and subtropical marine shrimps of the family Processidae. We present the first descriptions of the zoea I of Ambidexter symmetricus and Processa fimbriata and compare them with available published descriptions, in order to detect patterns to differentiate the genera. Among the species of Processidae, the zoea I of Ambidexter can be differentiated by the presence of a rostrum, and the resemblance to Nikoides and Processa, previously reported for adults, is now confirmed for the larval morphology. Based on the new descriptions, A. symmetricus and A. panamensis can be easily separated by four independent larval characters: anterior tubercle on the carapace (present in A. panamensis and absent in A. symmetricus), the antennal scale (segmented distally in A. panamensis and unsegmented in A. symmetricus), and the anal spine and second pereiopod (absent in A. panamensis and present in A. symmetricus). P. fimbriata can be separated from the other 11 species of Processa by means of two larval characters: 4 aesthetascs on the exopod of the antennules, and the presence of an anal spine.

DNA sequence database as a tool to identify decapod crustaceans on the Sao Paulo coastline

Abstract DNA barcoding has emerged as an efficient tool for taxonomy and other biodiversity fields. The vast and speciose group of decapod crustaceans is not an exception in the current scenario and comparing short DNA fragments has enabled researchers to overcome some taxonomic impediments to help broadening knowledge on the diversity of this group of crustaceans. Brazil is considered as an important area in terms of global marine biodiversity and some regions stand out in terms of decapod fauna, such as the São Paulo coastline. Thus, the aim of this study is to obtain sequences of the mitochondrial markers (COI and 16S) for decapod crustaceans distributed at the São Paulo coastline and to test the accuracy of these markers for species identification from this region by comparing our sequences to those already present in the GenBank database. We sampled along almost the 300 km of the São Paulo coastline from estuaries to offshore islands during the development of a multidisciplinary research project that took place for 5 years. All the species were processed to obtain the DNA sequences. The diversity of the decapod fauna on the São Paulo coastline comprises at least 404 species. We were able to collect 256 of those species and sequence of at least one of the target genes from 221. By testing the accuracy of these two DNA markers as a tool for identification, we were able to check our own identifications, including new records in GenBank, spot potential mistakes in GenBank, and detect potential new species.