Strubellia paradoxa

Strubellia paradoxa is a species of freshwater slug, a shell-less freshwater gastropod,[4] an aquatic gastropod mollusk within the clade Acochlidiacea.[1]

Strubellia paradoxa
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
(unranked):	clade Heterobranchia clade Euthyneura clade Panpulmonata clade Acochlidiacea clade Hedylopsacea[1]
Family:	Acochlidiidae[1]
Genus:	Strubellia Odhner, 1937[2]
Species:	S. paradoxa
Binomial name
Strubellia paradoxa (Strubell, 1892)[3]
Synonyms
Acochlidium paradoxum Strubell

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[5] within the superfamily Strubellioidea in the taxonomy of Bouchet & Rocroi.[6]

According to Schrödl & Neusser (2010)[1] Strubellia is in the family Acochlidiidae.[1]

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.[7] 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

1. Schrödl M. & Neusser T. P. (2010). "Towards a phylogeny and evolution of Acochlidia (Mollusca: Gastropoda: Opisthobranchia)". Zoological Journal of the Linnean Society 158: 124-154. doi:10.1111/j.1096-3642.2009.00544.x.
2. Odhner (1937). Zool. Anz. 120: 237.
3. Strubell A. (1892). [no title]. Verhandl. naturhist. Ver. preuss. Rheinlande, 49. Jahrg. Sitzung niederrhein. Ges. 13. Juni 1892: 62.
4. Strong E. E., Gargominy O., Ponder W. F. & Bouchet P. (2008). "Global Diversity of Gastropods (Gastropoda; Mollusca) in Freshwater". Hydrobiologia 595: 149-166. hdl:10088/7390 doi:10.1007/s10750-007-9012-6.
5. Rankin J. J. (1979). "A freshwater shell-less mollusc from the Caribbean: structure, biotics, and contribution to a new understanding of the Acochlidioidea". Life Sciences Contributions, Royal Ontario Museum 116: 123 pp.
6. Bouchet, Philippe; Rocroi, Jean-Pierre; Frýda, Jiri; Hausdorf, Bernard; Ponder, Winston; Valdés, Ángel & Warén, Anders (2005). "Classification and nomenclator of gastropod families". Malacologia. Hackenheim, Germany: ConchBooks. 47 (1–2): 1–397. ISBN 3-925919-72-4. ISSN 0076-2997.
7. Brenzinger, B., Neusser, T. P., Jörger, K. M., & Schrödl, M. (2011). “Integrating 3D microanatomy and molecules: natural history of the Pacific freshwater slug Strubellia Odhner, 1937 (Heterobranchia: Acochlidia), with description of a new species.” Journal of Molluscan Studies 77(4): 351-374.

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.