The Indo-West Pacific genus Coleusia Galil 2006, was recently described and now comprises seven species. We describe a new species from the western Arabian Gulf, Coleusia janani n. sp. The new species is closely related to the congener C. biannulata (Tyndale-Biscoe & George, 1962), and can be distinguished from other species at these genus congeners mainly by the straight upward apical shape of the male first pleopod (G1). An updated identification key to the species of Coleusia, as well as an overview of the geographical distribution of the species included in the genus are also presented.

The present study aimed to evaluate the current state of knowledge of marine and estuarine shrimp species from the suborder Dendrobranchiata and the infraorders Stenopodidea and Caridea, considering their diversity and distribution along the North and Northeast Brazilian coast (N/NE). The number of reported species rose from 124 to 169 since the Paulo S. Young’s Catalogue of Crustacea of Brazil, put out in 1998, which means an increase of 36.3%. Pernambuco (89 species) and Bahia (68 species) are the states that present the highest shrimp diversity, accounting for 53% and 40.5% of the total species registered for the N/NE regions, respectively. On the other hand, the states of Sergipe (21 species) and Piauí (13 species) contributed with only 12.5% and 7.7% of the total species registered at the moment.

Genetic analysis divides Panulirus argus into two different species, physically separated by the Amazon-Orinoco plume since the Last Glacial Maximum. Panulirus argus sensu stricto is distributed north of this biogeographic barrier and the second species to the south, occurring in Brazil. The Panulirus species in the Atlantic Ocean are being overfished and the standing stocks are unknown and still not considered endangered or threatened due to a deficiency of precise abundance data. The lack of data makes it impossible to undertake an effective conservation and management policy. In order to assist in the future management and conservation of the Spiny Lobster in the Atlantic Ocean and particularly for the indigenous species from Brazilian waters, this study formally recognizes and describes a new species, Panulirus meripurpuratus sp. nov., for what was previously known as P. argus in Brazilian waters, and differentiates it from Panulirus argus from North American waters and the Caribbean Sea. The work also presents an overview of the biogeographic distribution of the species and presents two identification keys to Atlantic species, one based on morphology and the other on live colouration.

Decapods play a crucial role within the reef ecosystem and the development of scuba diving as a survey tool has allowed researchers the opportunity to study the decapod–reef relationship more comprehensively. The present study describes the differences in decapod assemblages in intertidal and subtidal zones at a tropical coastal reef system in the southwestern Atlantic Ocean and reports the importance of scuba diving as a survey technique. A total of 71 decapods were recorded during the research; 42 in the intertidal zone mainly formed by small endobenthic species and 39 in the subtidal zone primarily large species only 10 were found to frequent both sample zones. The study extends the range of Brachycarpusholthuisi Fausto Filho 1966 in Brazil; and also demonstrates how scuba diving can be used to complement traditional methodologies and vice versa. The research shows the advantages of using scuba diving when studying trade endangered decapods, as the methodology allows access to cryptic habitats such as reef caves and underwater cavities which were inaccessible when using traditional techniques. In conclusion scuba diving represents a revolutionary non-destructive survey tool allowing the researcher to directly access a specific decapod assemblage in fragile reef environments and in protected marine areas