Tritonia hamnerorum
| Tritonia hamnerorum | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| (unranked): | clade Heterobranchia clade Euthyneura |
| Superfamily: | Tritonioidea |
| Family: | Tritoniidae |
| Genus: | Tritonia |
| Species: | T. hamnerorum |
| Binomial name | |
| Tritonia hamnerorum Gosliner & Ghiselin, 1987[1] | |
Tritonia hamnerorum is a species of dendronotid nudibranch. It is a marine gastropod mollusc in the family Tritoniidae.[2] It feeds exclusively on the sea fan Gorgonia ventalina.
Description
Tritonia hamnerorum grows to a length of about 15 millimetres (0.59 in) and its colour, pink or pale lavender, matches the colour of its host sea fan, Gorgonia ventalina. There are about twenty thin white stripes running the length of the body. There are two or three pairs of tentacles and a lobed rhinophore (sensory organ) at the anterior end and a series of nine, sparsely pinnate, gills down each side of the body.[1]
Distribution and habitat
Tritonia hamnerorum is found in the Caribbean area with its range extending from the Gulf of Mexico to Curaçao and the Cayman Islands.[3] It feeds on the sea fan Gorgonia ventalina and is found in the same shallow water and reef habitats as its host.[4]
Biology
Tritonia hamnerorum seems to feed exclusively on Gorgonia ventalina and extensive searches failed to locate any individuals on other parts of the reef, on mangroves or in seagrass beds. This nudibranch lays small clusters containing several hundred egg capsules on branches of its host coral. The morphology of the veliger larvae that hatch from these eggs suggest that they are planktonic. Juveniles feed on the soft tissue overlying the skeleton of the sea fan while adults feed on the polyps. Within its range, the distribution of Tritonia hamnerorum is very patchy. Usually one or a few individuals are found on a single sea fan, but very occasionally, as happened in an outbreak in 1992, a large number of juveniles occur. On this occasion, 1,700 were found in a dense aggregation on one side of an area of sea fan measuring 0.27 square metres (2.9 sq ft). Because these juveniles were all the same size, researchers hypothesized that they may not have become planktonic but may have remained on the host after hatching and fed on plankton, like their host, before undergoing metamorphosis.[4]
Gorgonia ventalina contains secondary metabolites including one, "julieannafuran", which is distasteful to predators. Tritonia hamnerorum seems to be unaffected by this and sequesters the compound, accumulating it in its tissues. This in turn makes the nudibranch distasteful to predatory fish, such as the bluehead wrasse (Thalassoma bifasciatum), which avoid consuming this species.[4]
References
- 1 2 Gosliner, Terrence M.; Ghiselin, Michael T. (1987). "A new species of Tritonia (Opisthobranchia: Gastropoda) from the Caribbean sea". Bulletin of Marine Science 40 (3): 428–436.
- ↑ Bouchet, P. (2005). Rocroi, J.-P., ed. Classification and nomenclator of gastropod families Malacologia: International Journal of Malacology, 47(1-2). ConchBooks. ISBN 3-925919-72-4.
- ↑ WoRMS (2012). "Tritonia hamnerorum Gosliner & Ghiselin, 1987". World Register of Marine Species. Retrieved 2012-10-10.
- 1 2 3 Cronin, G.; Hay, M. E.; Fenical, W.; Lindquist, N. (1995). "Distribution, density, and sequestration of host chemical defenses by the specialist nudibranch Tritonia hamnerorum found at high densities on the sea fan Gorgonia ventalina". Marine Ecology Progress Series 119: 177–189. doi:10.3354/meps119177.