personal observation).ĭuring a morphological and molecular-systematic study of Janthinidae, we obtained on loan a specimen of R. Juvenile Janthina float autonomously by creating a mucus stalk with a terminal bubble ( Simroth, 1895) and there is no evidence that males live in association with adult females ( Laursen, 1953 C.K.C.C. This proposed early life history is radically different from that of Janthina species. Colman hypothesized that they were dwarf males and that “they may live all their life on the float, or, after some time, make their own float and change sex to female, to complete the same sexual cycle as Janthina” ( Colman, 1986). jehennei Petit, 1853) from Bundagen Beach, New South Wales, Australia, with four conspecific individuals attached to the float. C.145648 here tentatively identified as R. Colman observed an adult female (Australian Museum reg. Recluzia is known to be oviparous ( Poorman, 1980) the only record distinguishing its life history from that of Janthina comes from a note in the grey literature by Colman (1986 see Supplementary material). Observations of Recluzia come from few preserved specimens ( Thiele, 1928 Abbott, 1963 Poorman, 1980) and as a result their ecology has largely been inferred from that of Janthina. Janthina janthina, however, is ovoviviparous and broods preveliger stages in the gonad. They are protandrous hermaphrodites ( Laursen, 1953) and most adult females cement egg capsules to their floats, which develop and hatch as planktotrophic veligers. Janthinids are highly specialized predators of neustonic cnidarians: the porpitids Velella velella and Porpita porpita, the siphonophore Physalia physalis and the actinarian Minyas spp. Five years of neuston sampling by the first author in the North and South Pacific gyre systems has yielded hundreds of Janthina specimens, but none of Recluzia. A Web of Science search for ‘ Recluzia’ yields a single record ( vs 10 for Janthina), reporting a beach stranding, in which the author noted that he could “now discontinue a search lasted for 25 years” ( Poorman, 1980). There are 15 nominal species, of which all but two were described in the nineteenth century and most were based on few (often single) specimens. Recluzia, on the other hand, has never received a formal taxonomic treatment. Cuvier, 1808 Graham, 1965) and has featured in several comparative morphological studies of caenogastropods ( Collin, 2000 Golding, Ponder & Byrne, 2009a, b). Janthina has been comprehensively revised ( Laursen, 1953, synonymized 60 named species to five), has been the topic of several anatomical works (e.g. Recluzia is much more poorly known than Janthina ( Fretter & Graham, 1962) and there is a large discrepancy in publishing effort between the two genera. They achieve floatation by a remarkable synapomorphy: using quick-setting mucus and rapid foot movements, they construct a bubble raft from which they are suspended ( Lalli & Gilmer, 1989). These two genera make up the family Janthinidae and share a most unusual ecology: they drift passively in the neuston, the vast ecosystem at the surface of the planet's subtropical oceans, which occupies 40% of the Earth's surface ( McClain, Signorini & Christian, 2004). Members of the genus Recluzia Petit, 1853 are also known as brown janthinas, because of their close relationship to the much more common violet snails of the genus Janthina ( Lalli & Gilmer, 1989 see Journal of Molluscan Studies, 77 cover). Here we present evidence to the contrary in a rare species of pelagic bubble-rafting snail, Recluzia cf. In fact, we know so little about the ecological roles and contributions of rare marine species that it is not farfetched to ask “Are rare species boring?” (R.T. Ecological studies of rare marine species lag behind their terrestrial counterparts because marine species are more difficult to sample and, as a result, taxonomic ambiguities abound ( Jones, Caley & Munday, 2002). Although the term ‘rare’ is qualitative, ecologists traditionally determine rarity using range and abundance, combined with guild-level comparisons ( Kunin & Gaston, 1997). Our lack of knowledge concerning the fundamental biodiversity of rare species in natural ecosystems impairs our ability to develop effective conservation programmes and to test hypotheses of community assembly. A.Most species in nature are rare, and their ecologies are poorly known ( Lyons et al., 2005).
0 Comments
Leave a Reply. |