Strubellia paradoxa
Introduction '''''Strubellia paradoxa''''' is a species of freshwater slug, a shell-less freshwater gastropod, an aquatic gastropod mollusk within the clade Acochlidiacea. ''Strubellia paradoxa'' is one of only two described species in the genus '''''Strubellia'''''.
Taxonomy In 2005, ''Strubellia'' was classified in the family '''Strubelliidae''' Rankin, 1979 within the superfamily Strubellioidea in the taxonomy of Bouchet & Rocroi.According to Schrödl & Neusser (2010) ''Strubellia'' is in the family Acochlidiidae.
Distribution ''Strubellia paradoxa'' is known only from Indonesia (Ambon Island). The species ''Strubellia wawrai'' occurs in the Solomon Islands.
Biology The biology of the genus is comparatively well-known. ''Strubellia'' species are reddish-brown, slender slugs of 5 to 40 mm length. They live under rocks in streams and creeks on volcanic islands and feed on the contents of calcareous egg capsules of other, herbivorous, snails (family Neritidae) occurring in the same habitat. Their radula is modified for slowly piercing these capsules with a sharp, saw-like central teeth of which some are worn down during the process. Calcareous spicules embedded below the skin help to stabilize the head during feeding; the nutritive contents of the capsules are slowly sucked out.The kidney and heart of ''Strubellia'' and other Acochlidiidae are enlarged compared to otherwise marine Acochlidiacea; this is thought to be an adaptation to the osmotic stresses of life in freshwater. ''Strubellia'' species are unusual among slugs in being sequential hermaphrodites, they become mature as males and later turn into females after copulation (protandry); this involves reorganization of the reproductive organs including loss of the elaborate copulatory organ. ''Strubellia'', and other Acochlidiidae, are thought to have an amphidromous life cycle: they spawn in freshwater; their swimming veliger larvae are then swept downstream into the river’s mouth or sea where they undergo metamorphosis to benthic snails. It is not known how and when larvae or juveniles do this and recolonize their freshwater habitat; it has been suggested that this may even happen by larger, more mobile dispersal vectors.
References
Further reading * Wawra E. (1974). "The rediscovery of ''Strubellia paradoxa'' (Strubell) (Gastropoda: Euthyneura: Acochlidiacea) on the Solomon Islands". ''The Veliger'' '''17'''(1): 8-10. * Wawra E. (1988). "''Strubellia paradoxa'' (Strubell 1892) (Gastropoda: Opisthobranchia) von den Solomon-Inseln". ''Zool Anz'' '''220''': 163-172. * Brenzinger B., Neusser T. P., Glaubrecht M., Haszprunar G. & Schrödl M. (2011). "Redescription and 3-dimensional reconstruction of the limnic acochlidian gastropod ''Strubellia paradoxa'' (Strubell, 1892) from Ambon, Indonesia". ''Journal of Natural History'' '''45''': 183-209.