Florence, was a brilliant Italian zoologist and ethologist, and one of the most well-known and active experts on alien aquatic species. Since her masters degree in Biology (1979) and her PhD in Animal Biology (Ethology) (1987), both obtained at the University of Florence, Francesca studied the behaviour and ecology of aquatic animals. Initially, most of her research concerned social recognition in crustaceans: she was particularly renowned for her studies on hermit crabs and crayfish, her principal model organisms.Then, from the 1990's onwards she worked in the field of invasion biology, her main interest until her death. Francesca devoted herself with enthusiasm and energy, not only to the problem of the invasive red swamp crayfish Procambarus clarkii, by revealing several aspects of its behavioral ecology, and by developing with her collaborators different methods for its control, but she gradually became an international expert on crayfish and more generally on aquatic alien species. In all aspects of her life, she was constantly driven by a continuous curiosity, thirst for knowledge and a will to face challenges; this was expressed by exploring and frequently opening new research fields. And she transmitted her drive and passion to the many students she supervised. One of the last papers with her contribution is published in this issue of Aquatic Invasions by Vera Gonçalves, her Portuguese PhD student working on the interaction between Procambarus clarkii and the zebra mussel Dreissena polymorpha, an issue of recent increasing interest in Francesca's team.
BackgroundBrooding brittle stars have a special mode of reproduction whereby they retain their eggs and juveniles inside respiratory body sacs called bursae. In the past, studying this phenomenon required disturbance of the sample by dissecting the adult. This caused irreversible damage and made the sample unsuitable for future studies. Micro X-ray computed tomography (μCT) is a promising technique, not only to visualise juveniles inside the bursae, but also to keep the sample intact and make the dataset of the scan available for future reference.FindingsSeven μCT scans of five freshly fixed (70 % ethanol) individuals, representing three differently sized brittle star species, provided adequate image quality to determine the numbers, sizes and postures of internally brooded young, as well as anatomy and morphology of adults. No staining agents were necessary to achieve high-resolution, high-contrast images, which permitted visualisations of both calcified and soft tissue. The raw data (projection and reconstruction images) are publicly available for download from GigaDB.ConclusionsBrittle stars of all sizes are suitable candidates for μCT imaging. This explicitly adds a new technique to the suite of tools available for studying the development of internally brooded young. The purpose of applying the technique was to visualise juveniles inside the adult, but because of the universally good quality of the dataset, the images can also be used for anatomical or comparative morphology-related studies of adult structures.
A new species of hermit crab, Pagurus fraserorum n. sp. (family Paguridae) is described from rocky subtidal reefs off KwaZulu-Natal, South Africa, and illustrated using both conventional drawings and colour photographs, and via three-dimensional (3D) X-ray micro-computed tomography (μCT). Because of the limitation μCT has in detecting very fine and soft structures, a novel approach of manually drawing setation and spinulation onto the two-dimensional images of the 3D visualizations was used to illustrate the pereopods. In addition, an interactive figure and rotation movie clips in the supplement section complement the species description, and the 3D raw data of the 3D type data are downloadable from the Gigascience Database repository. The new species is the sixth species of Pagurus Fabricius, 1775 reported from South Africa and is closely allied to the Indo-Pacific P. boriaustraliensis Morgen, 1990 and P. pitagsaleei McLaughlin, 2002, from which it differs by its shorter ocular peduncles, by the armature of the carpus of the right cheliped, and also in colouration. This study presents the first description of a hermit crab in which a majority of taxonomic details are illustrated through 3D volume-rendered illustrations. In addition, colour photographs and COI molecular barcodes are provided, and the latter compared to COI sequences of specimens from Western Australia previously identified as P. boriaustraliensis and of specimens of P. pitagsaleei from Taiwan, as well as to three additional South African members of the genus. The South African taxon was confirmed to be genetically distinct from all species tested.
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