Nembrotha purpureolineata is a species of colourful sea slug, a dorid nudibranch, a marine gastropod mollusc in the family Polyceridae. Nembrotha rutilans, classified as a separate species until 2008, has now been reclassified as Nembrotha purpureolineata.[3][4]
| Nembrotha purpureolineata | |
|---|---|
 | |
| Nembrotha purpureolineata | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Order: | Nudibranchia |
| Family: | Polyceridae |
| Genus: | Nembrotha |
| Species: | N. purpureolineata |
| Binomial name | |
| Nembrotha purpureolineata O'Donoghue, 1924[1] | |
| Synonyms | |
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Taxonomy
editNembrotha purpureolineata was first described from a preserved specimen collected from Abrolhos Islands off Western Australia by O'Donoghue in 1924. The short colour description given is probably enough to identify it to be the same as Nembrotha rutilans (Pruvot-Fol, 1931).[2] The description of this species was done purely from a painting of marine life on the Great Barrier Reef in a book by William Saville-Kent, (1893)[5] and so the earlier name has been given precedence.[3][4]
Distribution
editThis nudibranch occurs in the west of the tropical Indo-West Pacific Ocean.[6]
Description
editNembrotha purpureolineata is a large pale-bodied dorid that may reach a total length of 120 mm.[6] Individual specimens vary extremely in terms of colour and patterning, which can make it very difficult to differentiate from other Nembrothids. Thankfully, progress continues to be made in fine-scale differentiation within the genus, bringing great clarity to colour morphotypes that have been regarded as cryptic in the past[7].
The base colour of the body is always a creamy white, a blue to purple line always edges the foot and oral tentacles and there are always brown markings. The brown markings may present as longitudinal lines of variable thickness. A thinner line begins anterior to and passing beneath the rhinophores, running along the edge of the notum and meeting posterior to the gills to form a single broad line that runs down the tail. Thicker line or lines occur between these, and will form broad patches on the notum anterior and posterior to the gills. Some of these lines will terminate at the gill circle instead of parting around it. One or more lines occur on the sides of the body to meet at the tail as well. The lamellate rhinophores are described as "red or vermillion with blue or purple tips". The rhinophore stalks are pink, and the sheaths blue to purple with some yellow below, either concentrated or diffuse. The gill leaves are red to vermillion, the gill stalks are purple, and the there is diffuse yellow at the base[3].
The second colour morphotype, finally backed by genetic data[7], has no brown lines at all, and instead has two large brown patches on its notum, one that sits anterior to the gills, and the other posterior. Pigmentation of the patches can vary in intensity, ranging from a dark brown that is nearly black, to a paleness that looks nearly brownish-orange. Rhinophore clubs range from bright red to a brownish-orange and are tipped with white. The rhinophore stalks are white, and the upper edge of the rhinophore sheaths may range from pink to purple. The base of the rhinophoral sheath will have yellow-greenish markings that may extend to meet the other base. This yellow-greenish colour will also be found as a well-defined band surrounding the base of the gill stalks, and also as a small patch at the tip of the tail. Another smaller patch may or may not be at tip of the tail that corresponds to the colour of the upper edge of the rhinophoral sheaths, the colour of the gills, or both. The pigmentation of the gills can range anywhere from brownish red to a pinkish maroon, the deepest pigmentation occurring at the gill fronds and fading into white as it travels down the gill stalks.
This is the form that is constantly confused with Nembrotha chamberlaini. The most reliable method of differentiation is to observe the gills and surrounding area; in N. chamberlaini, the gills and gill stalks are always uniformly pigmented with no variation, and end in patch of the same colour on the back. However, in this colour morphotype of N. purpureolineata, the pigmentation of the gills fades into white as it travels down the stalks, and below that will be a well-defined band of yellow- or greenish-brown where the stalks join the body.
It is very important to note that there will be no bright orange colouration on the notum ever. Previously, select specimens were attributed to N. purpureolineata or Nembrotha aurea depending on the locations of bright orange patches. However, new data has identified these specimens as their own unique species, Nembrotha lorosae[7].
Nembrotha purpureolineata.
Ecology
editThis species feeds on ascidians and tunicates. It has been seen feeding on the yellow-lined ascidian, Clavelina meridionalis.[6]
References
edit- ↑ O'Donoghue, C. H. (1924) "Report on Opisthobranchiata from the Abrolhos Islands, Western Australia, with description of a new parasitic copepod. Journal of the Linnean Society, London 35: 521-579, Pls. 27-30.
- 1 2 Pruvot-Fol A. (1931) "Note 10. Nudibranches Australiens figures par Saville Kent". Bull. Mus. Nat. hist. nat. Paris 2(3): 754-755.
- 1 2 3 Pola M., Cervera J. L. & Gosliner T. M. (2008) "Revision of the Indo-Pacific genus Nembrotha (Nudibranchia: Dorididae: Polyceridae), with description of two new species". Scientia Marina 72(1): 145-183. doi:10.3989/scimar.2008.72n1145
- 1 2 (2 July 1999) Nembrotha rutilans. Sea Slug Forum, accessed 10 December 2009.
- ↑ William Saville-Kent W. (1893) The Great Barrier Reef of Australia. Plate 13, fig. 9 (Ancula sp.).
- 1 2 3 Nembrotha purpureolineata O'Donoghue, 1924. Sea Slug Forum, accessed 10 December 2009.
- 1 2 3 Pola, M.; Paz-Sedano, S.; Martín, P. G.; Warren, L.; Noble, K.; Martín-Hervás, M. D. R. (2026). The most wanted! Gorgeous, delicate and surprising: description of three new polycerid species (Mollusca, Heterobranchia) from East Timor. Zootaxa. 5793(1): 193-217.
Further reading
edit- Debelius H. (2001). Nudibranchs and Sea Snails. Frankfurt, Germany: IKAN - Unterwasserarchiv.
External links
edit
- Photos of Nembrotha purpureolineata in the Sealife Collection