Austinixa bragantina Coelho, 2005: a junior synonym of A. aidae (Righi, 1967) (Brachyura: Pinnotheridae) supported by integrative morphological and molecular data.

Austinixa bragantina Coelho, 2005, described from Ilha Canela, Bragança, state of Pará, Brazil, is established as a junior synonym of A. aidae (Righi, 1967) based on morphological (gross morphology and scanning electron microscopy) and molecular (16S rRNA mitochondrial marker) evidence. The phylogenetic tree was obtained through the Maximum Likelihood method aiming to contextualize A. bragantina among related species. We provide a redescription, an updated synonymy, and remarks on the intra-specific morphological variability of A. aidae to clarify some taxonomic inconsistencies previously reported. Austinixa hardyi Heard & Manning, 1997, a species of uncertain taxonomic status, was confirmed genetically to also be a synonym of A. aidae.

Populational Evidence Supports a Monogomous Mating System in Five Species of Snapping Shrimps of the Genus Alpheus (Caridea: Alpheidae).

The objective of this study was to verify if populations of the snapping shrimps Alpheus angulosus, A. bouvieri, A. carlae, A. estuariensis and A. nuttingi from Pernambuco, northeastern Brazil, are monogamous based on population data. If these species are monogamous, then the populations must exhibit: 1) higher frequency of individuals living in pairs; 2) non-random population distribution, i.e., pairs are found more often than expected by chance alone; 3) males paired with females regardless of their reproductive condition; 4) sexual dimorphism regarding body size and chelipeds weaponry little pronounced among paired individuals and 5) size-assortative pairing. Our samplings were carried out in August 2015, February and August 2016 and February 2017, in the intertidal zone, during low spring tides. We captured a total of 2,276 specimens: 300 of A. angulosus, 393 of A. bouvieri, 374 of A. carlae, 403 of A. nuttingi and 806 of A. estuariensis. The key population parameters (indicators 1, 2, 3, 4, 5 above) for the four species strongly suggest that all four undergo monogomous mating. Although our frequency distribution demonstrated a higher tendency to find solitary individuals in A. nuttingi and A. estuariensis, the other studied features agree with the occurrence of monogamy in those populations. Lastly, the sexual differences observed in the chelipeds and the existence of solitary egg-carrying females indicated that monogamy in the five species is not rigid, i.e., heterosexual pairing may not last long, due to possible competition between males for females or refuge.

Delimiting the snapping shrimp Alpheus lobidens De Haan, 1849 (Caridea: Alpheidae) based on morphological and molecular data.

Our aim was to delimit the taxonomic status of the snapping shrimp Alpheus lobidens De Haan, 1849, based on morphological and molecular analyses of the topotype material from Nagasaki (Japan). We provide a redescription, detailed illustrations, and molecular data. Through comparisons with close-related species, we also tested the taxonomic status of A. inopinatus Holthuis Gottlieb, 1958 and A. buckupi Almeida, Terossi, Araújo-Silva Mantelatto, 2013. We examined 74 specimens previously identified as A. lobidens, 84 specimens of A. buckupi, and 30 of A. inopinatus. The morphological analysis was based on the examination of 68 characters. The molecular analysis included mitochondrial gene sequences (16S) of 18 individuals: six A. lobidens, three A. buckupi, one A. inopinatus, and eight individuals of other species of Alpheidae. The morphological analysis revealed that A. lobidens sensu stricto is consistently distinct of A. lobidens sensu lato, A. inopinatus and A. buckupi. The genetic analyzes (Bayesian Inference and p-distance) corroborated the morphological results and showed a clear separation between them. The highest values of genetic divergence (p-distance) (19%) were observed between A. lobidens sensu stricto and A. buckupi, and between A. lobidens sensu stricto and A. lobidens sensu lato from Australia (Northern Territory). The lowest divergence (12%) occurred between A. lobidens sensu stricto and A. lobidens sensu lato from Marshall Islands. Based on our results, the occurrence of A. lobidens sensu stricto is currently restricted to the type locality in Japan, and A. inopinatus and A. buckupi are valid taxa. Delimiting A. lobidens sensu stricto is relevant since the name A. lobidens has been applied to cryptic species, resulting in a high unclear taxonomic state.

Congruence between morphology and molecular data supports the distinction between the snapping shrimps Alpheus macrocheles and A. amblyonyx (Caridea, Alpheidae).

The snapping shrimp Alpheus macrocheles (Hailstone, 1835b) is widely distributed across the Atlantic Ocean and was originally described from Hastings, England, based on a very brief description with limited morphological details and diagnostic illustrations. The morphologically similar A. amblyonyx Chace, 1972, type locality Quintana Roo, Mexico, is a western Atlantic taxon. The superficial description of A. macrocheles by Hailstone and the high similarity with A. amblyonyx has led to taxonomic confusion regarding the precise identification of these species. Thus, our objective was to reexamine these two species, based on a combined analysis of morphological-including a redescription for A. macrocheles and new morphological characterization of A. amblyonyx-and molecular data. In total, 42 morphological characters were analyzed, in addition to a phylogenetic analysis of 16S ribosomal RNA (rRNA) gene sequences. A Bayesian Inference analysis recovered A. macrocheles and A. amblyonyx as distinct clades supporting the taxonomic distinction between them. The tree topology suggests that A. macrocheles is more closely related to A. crockeri (Armstrong, 1941) and A. puapeba (Christoffersen, 1979) than to A. amblyonyx, which forms the sister group to a well-supported clade containing these three species. This contribution conclusively distinguishes between A. macrocheles and A. amblyonyx and points out the need for a comprehensive review involving all species of the larger A. macrocheles group.

Using integrative taxonomy to establish the status of Alpheus peasei (Armstrong, 1940) (Decapoda: Alpheidae) as a single species throughout its distribution.

The distribution of the western Atlantic snapping shrimp Alpheus peasei (Armstrong, 1940) has a large gap (approx. 12° of latitude) between Tobago and the northeast of Brazil (State of Ceará). Here we analyzed specimens of A. peasei from its entire distribution range and type-locality (Bermuda), to test the hypothesis that they belong to a single species. The morphological analysis included the usual taxonomic characters as well as additional ones (such as mouthparts). The molecular analysis was based on the mitochondrial genes Cytochrome Oxidase I and 16S rRNA. The results of both analyses were congruent and indicated that A. peasei is a single species throughout its known distribution. As such, they indicated a connectivity between Northwestern and Southwestern Atlantic populations of A. peasei. The gap in distribution may be explained by scarce samplings in the North Brazil Shelf province and/or by passive larval dispersal. Our results also extend the known distribution of A. peasei in the northwestern Atlantic (Barbados, Belize and Costa Rica), and add a new record from the Brazilian coast (Pernambuco).

Morphology and DNA Data Reveal a New Shrimp Species of Genus Latreutes Stimpson, 1860 (Decapoda: Hippolytidae) from the Western Atlantic.

The genus Latreutes Stimpson, 1860 comprises 17 described species of marine shrimps, most of them distributed in the Indo-West Pacific and eastern Pacific. Only three species are recorded in the Atlantic. When comparing specimens of Latreutes parvulus (Stimpson, 1871) from both sides of the Atlantic by means of a combination of morphological and molecular data, we recognized a new species of Latreutes from Brazil (Rio Grande do Norte, Bahia, Rio de Janeiro and São Paulo). The phylogenetic tree generated on the basis of the 16S gene showed a clear separation of the specimens of the new species from the other closely related species analyzed. The analyses also evidenced that the new species and L. parvulus are sister taxa. Although very similar, both species can be easily separated by features of the scaphocerite and eyestalk. Rostrum form and dentition, characters usually used for L. parvulus recognition, were highly variable in both species. Thus, herein the new species is described, illustrated, and compared with morphological similar species of Latreutes. A key for the Atlantic species is also provided.

Checklist of decapods (Crustacea) from the coast of São Paulo State (Brazil) supported by integrative molecular and morphological data: II. Infraorder Caridea: family Alpheidae.

This study is part of a series of checklists resulting from a long-term multidisciplinary project on the biodiversity of decapod crustaceans from the marine and coastal environments (including estuaries) of São Paulo State (Brazil). For that, we integrated molecular techniques (mitochondrial DNA markers) and morphological analyses of adult specimens for an accurate and detailed identification. The DNA markers were used when the morphological identification was doubtful, particularly in the recognition of cryptic species. This second manuscript presents a checklist of the Alpheidae caridean shrimps from the coast of São Paulo. We report the occurrence of Alpheus cf. paracrinitus and Synalpheus townsendi for the first time in the region. Based on our survey, 39 species of Alpheidae are known for this region: Alpheus (21 spp.), Athanas (2 spp.), Automate (2 spp.), Leptalpheus (1 spp.), Salmoneus (3 spp.), and Synalpheus (10 spp.). We collected 28 species and obtained cytochrome oxidase subunit I (barcode region) and/or 16S partial sequences of 26 of them. These sequences may be used for phylogenetic and populational analyses in further studies.

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.

Shallow-water stenopodidean and caridean shrimps from Abrolhos Archipelago, Brazil: new records and updated checklist.

This study deals with a recent collection of stenopodidean and caridean shrimps made in the Abrolhos Archipelago, Bahia, Brazil, in July and August 2013. Sampling was carried out in the vicinity of Ilha de Santa Bárbara (17°57'49"S 38°41'53"W). Specimens were obtained by hand or using small hand nets in tide pools or under rocks in the intertidal zone. Part of the material was collected by scuba diving in the shallow subtidal, to a maximum depth of 11 m. We obtained a total of 18 species, 12 of which are reported for the first time for the Abrolhos and 4 as new records for the state of Bahia. The distributions of Microprosthema semilaeve (von Martens, 1872), Typton gnathophylloides Holthuis, 1951, Alpheus verrilli (Schmitt, 1924) and Alpheopsis cf. trigona (Rathbun, 1901) are extended from their previously known ranges. The occurrence of Automate cf. rectifrons Chace, 1972 on the Brazilian coast is confirmed. We thus provide an updated checklist of stenopodidean (2 species) and caridean (29 species) shrimps from the Abrolhos Archipelago, incorporating and critically evaluating previous records. 

A new snapping species of the shrimp genus Typton Costa, 1844 (Decapoda: Palaemonidae) from the coast of São Paulo, southeastern Brazil.

A new species of the palaemonid shrimp genus Typton Costa, 1844, Typton fapespae sp. nov., is described based on several specimens collected in Ubatuba and São Sebastião, northern coast of the state of São Paulo, Brazil. Most specimens were found in association with sponges, including Mycale (Zygomycale) angulosa (Duchassaing & Michelotti, 1864) (Demospongiae: Mycalidae); however, one paratype from Ubatuba was extracted from a colony of the bryozoan Schizoporella errata (Waters, 1878) (Gymnolaemata: Schizoporellidae). In T. fapespae sp. nov., the posterodorsal margin of the sixth abdominal segment bears a strong median tooth, a feature shared with T. hephaestus Holthuis, 1951, T. holthusi De Grave, 2010 and T. spongicola Costa, 1844. However, the new species can be separated from each of these three species by at least two morphological features. 

Potamalpheops tyrymembe sp. n.: the first southwestern Atlantic species of the shrimp genus Potamalpheops Powell, 1979 (Caridea: Alpheidae).

A new species of the alpheid shrimp genus Potamalpheops Powell, 1979, P. tyrymembe sp. n., is described based on several specimens collected from burrows of the ucidid crab Ucides cordatus (Linnaeus, 1763) and other, unknown burrowing decapods, on a mangrove flat between the Baiano and Serra rivers, Povoado de Tremembé, Maraú, state of Bahia, Brazil (14º08'51.9"S, 39º05'04.4"W). The new species belongs to the P. monodi (Sollaud, 1932) species group, based on the presence of two pairs of spiniform setae on the distal margin of the telson and non-enlarged male chelipeds. It is characterized by a short rostrum and absence of setae on the pterygostomial angle of the carapace.

Description of Alpheus buckupi spec. nov., a new amphi-Atlantic snapping shrimp (Caridea: Alpheidae), based on morphological and molecular data.

A new amphi-Atlantic snapping shrimp of the genus Alpheus Fabricius, 1798, Alpheus buckupi spec. nov., is described and illustrated based on material collected from the western (Orinoco Delta, Venezuela to São Paulo, Brazil) and eastern Atlantic (São Tomé and Príncipe). The new species is morphologically similar to members of the A. lobidens De Haan, 1850 species complex, from the Indo-Pacific, including A. inopinatus Holthuis & Gottlieb, 1958 from the eastern Mediterranean, and the Red Sea to Pakistan, especially based on major and minor chelae configuration. We also characterized this new species in terms of DNA sequences of a ribosomal 16S subunit and compared it in a phylogenetic context. These analyses showed a clear separation of the specimens of A. buckupi spec. nov. from similar species of the A. edwardsii (Audouin, 1826) species group, including some morphologically close species such as A. cf. lobidens, A. heterochaelis Say, 1818, A. pontederiae de Rochebrune, 1883, A. sp. aff. euphrosyne De Man, 1897, and A. microrhynchus De Man, 1897.