ABSTRACT An extensive review of primary and secondary occurrence data, including several new records, of the South American native antlion Dimares elegans (Perty) revealed that this species is endemic to regions of stressful water regime (Caatinga, Cerrado, Chaco and temperate fields) and adjacent areas in Amazon rainforest, Atlantic forest and Pampas. Its known distribution is from Santarém, Pará state, northern Brazil to Río Negro, Chimpay, northwestern Argentina. The known distribution of the species in Brazil has been extended, registering several areas above the São Francisco River (former possible northeastern limit). New limits further east were established from new primary records. For the first time the species is registered from the Brazillian states of Maranhão, Piauí, Rio Grande do Norte, Paraíba, Bahia, Goiáis, Tocantins, Minas Gerais, Mato Grosso do Sul, São Paulo and Paraná, Brazil. Historical data of occurrence in Goiás (Cerrado) have been geopolitically rectified (Tocantins) and, present occurrence in Goiás is reported by primary data in two new localities. Antlions are mostly xerofilous species, however with recent data this species might present much wider distribution than restricted to seasonally dry forests. records Perty (Perty Caatinga, Caatinga (Caatinga Cerrado fields rainforest Pampas Santarém state Negro Chimpay Argentina extended former limit. limit . limit) Maranhão Piauí Norte Paraíba Bahia Goiáis Tocantins Gerais Sul Paraná (Cerrado (Tocantins localities forests

Abstract Ecosystem engineering species create, modify, and/or maintain the characteristics of the environment. The polychaete Phragmatopoma caudata builds large sand reefs in the intertidal region of the Brazilian coast with high structural complexity, favoring the increase of diversity and interactions among the species associated. However, there are no studies concerning the association of polychaetes with crustacean macrofauna in the northeastern Brazil ecoregion, leaving an information gap on baseline biodiversity. Our aim was to analyze the effect of P. caudata colonies (PC) on the local diversity of macrocrustaceans compared to the rocky shore (RS) microhabitat. Monthly collections were carried out in low tide from September 2015 to August 2016 on 10 × 10 m quadrants for fauna and environmental variables (temperature and salinity) samples. In each microhabitat, the capture effort was two hours by two researchers. We collected 3,390 individuals, 60% associated with the colonies of PC and 40% with the RS. The PC obtained higher Shannon diversity, Pielou evenness and species richness coupled with milder water temperature and salinity conditions (minor air exposure during tide), compared to the RS that obtained greater species dominance and more extreme abiotic conditions (major air exposure). The Porcellanidae family stood out because all its species were highly abundant and had high occurrence in the colonies. The tropical Brazil porcelain crab Pachycheles greeleyi was dominant in both microhabitats (major dominance in PC). The structural complexity in the reefs of PC promoted higher availability of niches for the species, as more shelter for the resident species and refugium for temporary species with preference for more complex microhabitats. Conservation managers should prioritize the health of these colonies and subsequent species that constitute important ecosystemic and fishery resources.

The evaluation of population characteristics, particularly those of endemic species, aids in population preservation and management. Hermit crabs present an innate behavior of occupying shells, which tends to individual needs and limits their distribution. This study characterized the pattern of occupation of gastropod shells by the hermit Loxopagurus loxochelis in three bays of the southwestern coast of Brazil. Monthly collections were made from January/1998 to December/1999 in the bays Ubatumirim (UBM), Ubatuba (UBA) and Mar Virado (MV) with a shrimping boat. Overall, ten species of gastropod shells were occupied by L. loxochelis. The shell of Olivancillaria urceus represented 66.8% of those occupied. Morphometric relationships demonstrated a differential occupation of the more abundant shells among demographic groups, where most of the males occupied O. urceus, non-ovigerous females occupied O. urceus and Buccinanops cochlidium, and ovigerous females occupied B. cochlidium and Stramonita haemastoma. Most of the individuals occupied the more abundant shells, considered adequate for the morphology of this hermit crab species. Thus, the studied bays seem to be stable and propitious environments for population perpetuation and the settlement of new individuals.