The sponge crabs of Western Australia and the Northwest Shelf with descriptions of new genera and species (Crustacea: Brachyura: Dromiidae).

The Dromiidae of Western Australia are summarized primarily based on specimens from the collection of the Western Australian Museum and some additional material from the Australian Museum, Sydney. The genus Alainodromia McLay 1998, is recorded from Camden Sound, Australia, as a new species Alainodromia dambimangari sp. nov. New evidence suggests that the species of Alainodromia are very likely shell carriers that also have direct development. Five species of Cryptodromia are reported from Western Australia and a new genus, Baccadromia gen. nov., is erected for Dromia (Cryptodromia) bullifera Alcock, 1900. The genus Lamarckdromia Guinot Tavares, 2003 is revised and now includes three species: L. beagle sp. nov., L. excavata (Stimpson, 1858) and L. globosa (Lamarck, 1818). Six species of Dromiidae are new to Australia: Baccadromia bullifera (Alcock, 1900), Cryptodromia amboinensis (De Man, 1888), C. pileifera Alcock, 1901, Epigodromia rotunda McLay, 1993, and Foredromia rostrata McLay, 2002. New records for Western Australia include: Cryptodromia hilgendorfi De Man, 1888, Epigodromia areolata (Ihle, 1913) and Lewindromia unidentata (Rppell, 1830). A total of 31 species of dromiid crabs are now known from Western Australian coast with five species endemic to the state. There are more than 40 species of Dromiidae known from Australia of which about 40% are endemic.

To invade or not to invade? Exploring the niche-based processes underlying the failure of a biological invasion using the invasive Chinese mitten crab.

Invasive alien species represent a serious threat to global biodiversity, causing considerable damage to native ecosystems. To better assess invasion risks, it is essential to better understand the biological processes that determine the success or failure of invasions. The catadromous Chinese mitten crab Eriocheir sinensis, whose native distribution is the Pacific Coast of China and Korea, has successfully invaded and established populations in North America and Europe. In Japan, where E. sinensis is also regarded as potentially invasive and multiple introduction vectors exist, the species is not yet established. These settings can be used to explore niche-based processes underlying the apparent failure of a biological invasion. We first quantified native and invasive realized niches of E. sinensis in freshwater habitats using geometrical n-dimensional hypervolumes. Based on the assumption of niche conservatism, we then projected habitat suitability of this species in Japan using species distribution models (SDMs) calibrated with distinct sets of distribution data: native occurrences, invasive occurrences, and both. Results showed that E. sinensis has undergone either niche shifts or niche contractions during invasions in different areas of the world. Projections from SDMs indicate that although part of Japan is suitable for E. sinensis, this does not include the freshwater habitats around the Ariake Sea, which is considered to be a suitable marine environment for E. sinensis larvae. The mismatch between suitable freshwater and marine environments provides a possible explanation for the failure of establishment of E. sinensis in Japan to date. Our findings have useful general implications for the interpretation of biological invasions.

Revision of the shell-carrying crab genus Conchoecetes Stimpson, 1858 (Crustacea: Brachyura: Dromiidae).

The genus Conchoecetes Stimpson, 1858, has long been considered to include three species: C. artificiosus (Fabricius, 1798), C. andamanicus Alcock, 1900, and C. intermedius Lewinsohn, 1984. The type species, C. artificiosus, has been assumed to be widely distributed throughout the Indo-West Pacific and a fourth species, C. conchifera (Haswell, 1882), from Australia, has been regarded as a synonym. The enigmatic and long overlooked "Caphyra pectenicola Adams, in Belcher, 1848" is shown to be a species of Conchoecetes occurring in Java, Singapore and the Gulf of Thailand. We review the status of these species, establish C. conchifera as a valid species, and describe five new species: C. atlas n. sp., C avikele n. sp., C. chanty n. sp., C. investigator n. sp. and C. pembawa n. sp. In this revision we recognize 10 valid species in Conchoecetes. They are distributed from Southern Africa, across the Indian Ocean to Australia and northwards to China. Formerly considered to be cosmopolitan, C. artificiosus is restricted to India, Sri Lanka Pakistan, as well as the Persian Gulf and Madagascar, while C. intermedius, first discovered near Madagascar, is shown to be the most widespread species occurring from Africa to China.

Hard-shell mating in Neohelice granulata: the role of ecdysone in female receptivity and mate attraction.

Most brachyuran females become receptive during the intermolt period, a condition considered "derived". However, as far as we know, studies testing the existence and function of pheromones in decapods are based on species which have mating linked to molting, a condition considered as "ancestral". For the first time, we studied some physiological and morphological processes involved in Neohelice granulata intermolt female crabs becoming receptive and potentially attracting males. We found that receptive females have mobile vulvae opercula due to a softening process of the cuticle hinge which showed lower calcium levels compared to the hinge of unreceptive females. Local softening of the hinge was stimulated by a low concentration of ecdysone during the intermolt period. A putative pheromone liberated by receptive females to attract males is presumed to be released through the mobile vulvae and not through the urine.

Tri-locus sequence data reject a "Gondwanan origin hypothesis" for the African/South Pacific crab genus Hymenosoma.

Crabs of the family Hymenosomatidae are common in coastal and shelf regions throughout much of the southern hemisphere. One of the genera in the family, Hymenosoma, is represented in Africa and the South Pacific (Australia and New Zealand). This distribution can be explained either by vicariance (presence of the genus on the Gondwanan supercontinent and divergence following its break-up) or more recent transoceanic dispersal from one region to the other. We tested these hypotheses by reconstructing phylogenetic relationships among the seven presently-accepted species in the genus, as well as examining their placement among other hymenosomatid crabs, using sequence data from two nuclear markers (Adenine Nucleotide Transporter [ANT] exon 2 and 18S rDNA) and three mitochondrial markers (COI, 12S and 16S rDNA). The five southern African representatives of the genus were recovered as a monophyletic lineage, and another southern African species, Neorhynchoplax bovis, was identified as their sister taxon. The two species of Hymenosoma from the South Pacific neither clustered with their African congeners, nor with each other, and should therefore both be placed into different genera. Molecular dating supports a post-Gondwanan origin of the Hymenosomatidae. While long-distance dispersal cannot be ruled out to explain the presence of the family Hymenosomatidae on the former Gondwanan land-masses and beyond, the evolutionary history of the African species of Hymenosoma indicates that a third means of speciation may be important in this group: gradual along-coast dispersal from tropical towards temperate regions, with range expansions into formerly inhospitable habitat during warm climatic phases, followed by adaptation and speciation during subsequent cooler phases.