Most species of bryozoans have short-lived larvae with limited dispersal potential, yet many of these species possess global distributions. In this study, we report the first occurrence from the western Atlantic Ocean of the widely distributed arborescent bryozoan Tricellaria inopinata d 'Hondt and Occhipinti-Ambrogi, 1985. This species was collected in Eel Pond, Woods Hole, Massachusetts, in September 2010. At that time, T. inopinata colonies had already formed dense conspecific aggregations at some collection sites, despite the presence of several other arborescent bryozoans. Sites were monitored throughout 2011 to track the success of this introduction, and to assess the reproductive timing of T. inopinata in Eel Pond. To determine the likelihood of T. inopinata persisting in Eel Pond and competing with previously established bryozoans, rates of metamorphic initiation, metamorphic completion, and overall offspring survivability were compared to one of the other dominant arborescent species. Finally, we provide taxonomic details to aid in identifying these animals, consider the potential mode of transport, and discuss the potential ecological implications resulting from this introduction.

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We described the ultrastructure and histochemistry of the reproductive system of five Callinectes species, and evaluate the seasonal variation in weight of the reproductive system and hepatopancreas by comparing annual changes of somatic indices. The somatic indices changed little throughout the year. In Callinectes, spermatogenesis occurs inside the lobular testes and, within each lobule, the cells are at the same developmental stage. Spermatogenesis and spermiogenesis follow the same development pattern in all Callinectes studied. Mature spermatozoa are released into the seminiferous ducts through the collecting ducts. Cells of the vas deferens are secretory as evidenced by rough endoplasmic reticulum, Golgi complex, and secretory vesicles that produce the seminal fluid. The anterior vas deferens shows two portions: proximal and distal. In proximal portion (AVDp), spermatozoa are clustered and embedded in an electron-dense, basophilic glycoproteinaceous secretion Type I. In the distal portion (AVDd), the spermatophore wall is formed by incorporation of a less electron-dense glycoproteinaceous secretion Type II. The secretion Type I change to an acid polysaccharide-rich matrix that separates the spermatophores from each other. The median vas deferens (MVD) stores the spermatophores and produces the granular glycoproteinaceous seminal fluid. The posterior vas deferens (PVD) has few spermatophores. Its epithelium has many mitochondria and the PVD seminal fluid changes into a liquid and homogeneous glycoprotein. Many outpocketings in the PVD and MVD help to increase the fluid production. Overall, the reproductive pattern of Callinectes is similar to other species that produce sperm plugs. The secretions of AVD, MVD, and PVD are responsible for the polymerization that forms the solid, waxy plug in the seminal receptacle. The traits identified here are common to all Portunidae species studied so far.

A marine biological invasion is a natural process accelerated by human activities, and the crab Charybdis hellerii is an example of a globally widespread invasive species. This study evaluated color variation in C. hellerii and its relationship to the sex, size and sexual maturity of these crabs, and compared the efficiency of a freeware digital image-editing program with a commercially available program. The color of the individuals was analyzed using standardized digital images. The color pattern varied significantly with size; smaller and immature individuals were darker than larger and mature ones. The female abdomen changed in morphology and color with sexual maturity, becoming wider and orange-colored. There was no statistical difference in the color values between males and females and immature males did not show morphological or color differences in their abdomen. This study highlights the possible relationships of the color and physiological state of the reproductive system, which could help in future studies of behavior, avoiding the need to dissect and/or remove individuals from nature for assessment of sexual maturity. The freeware program showed the same efficiency in digital image analysis as a widely known commercial program.

BioInvasions Records is a new open access peer-reviewed international journal focusing on the rapid publication of applied research on invasive species and biological invasions in aquatic and terrestrial ecosystems around the world. BioInvasions Records is a continuation of the former Aquatic Invasions Records, an electronic supplement of the open access international journal Aquatic Invasions. BioInvasions Records is devoted to bridging the gap between scientific research and the use of science in decision-making, regulation, and management as it pertains to the introduction of invasive alien species (IAS) and biodiversity conservation. Thus, this new journal provides a forum for professionals involved in research and management of IAS. BioInvasions Records contributes to rapid information dissemination, risk assessment procedures, and early detection and rapid response on IAS. The incorporation of open access journals into the REABIC information system represents an innovative approach to IAS-related information management and ensures sustainability of REABIC-based information management tools.

This study investigated the behaviour of Pomacea bridgesii, describing the daily activity, substrate selection and the influence of the flood regime in the Amazon, the species’ native habitat. The present study described the daily activity and substrate selection, and evaluated the activity adaptations of the gastropods in a simulated flood-pulse regime. Gastropods were collected in Amazonas, Brazil, in June 2013. Assessments of the daily behaviour, substrate selection, and flood-pulse simulation were made in experimental water tanks. The snails were observed hourly for 48h, and their behaviour recorded on an ethogram. The snails were more active during the night, when up to 80% of them moved about. In general, during both day and night, the gastropods used the pebble substrate most often. Comparing the day periods, a significant proportion of the individuals that were using the pebbles moved to other substrates (t=5; d.f.=2; P=0.03). The interaction of the behaviour of P. bridgesii with the simulated flood-pulse regime showed a statistical difference between the dry period and the period of maximum water level. The water regime of the Amazon floodplain directly influenced the activity of P. bridgesii, with responses including self-burying and activity interruption, with the operculum closed to minimise water loss.

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