Paraganitus
| Paraganitus | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Gastropoda |
| Family: | Parhedylidae |
| Genus: | Paraganitus Challis, 1968[1] |
| Species: | P. ellynnae |
| Binomial name | |
| Paraganitus ellynnae Challis, 1968 | |
Paraganitus ellynnae is a species of sea slug, an acochlidian, a shell-less marine gastropod mollusc in the family Parhedylidae.
Paraganitus ellynnae is the only species in the genus Paraganitus.[2]
Description
[edit]Paraganitus ellynnae is smaller than 5 mm and is externally symmetric.[2] It has no shell in adults, and no operculum in adults.[2] It has also no head shield and no posterior shield.[2] It is able to partially retract parts of its anterior body into a temporal visceral cavity.[2] The visceral sac is largely separated from the rest of the body.[2] The mantle is robust.[2] The visceral hump is conical.[2] The tail is short and pointed.[2] The foot is narrow, the anterior foot edge is rounded and it can crawl on the whole foot.[2] It has no mantle cavity.[2] It has elongated/pointed rhinophores.[2] Like all acochlidians, it has oral (= labial) tentacles.[2] Paraganitus ellynnae has long and slightly recurved oral tentacles.[2] Oral tentacle nerves have been present in all examined acochlidians to date, but those nerves were not examined in this species.[2]
Like all acochlidians, it lacks plicate gills.[2] The position of the anus is unknown.[2] It has no calcareous spicules, but it has integumental concrements.[2] It has no keel on the visceral hump.[2]
It has aggregations of precerebral ‘accessory ganglia’.[2] It has no eyes.[2] The presence or absence of Hancock's organ is unknown.[2] It has prepharyngeal CNS as is the case in all other acochlidians.[2]
Ecology
[edit]Paraganitus ellynnae is marine and is a mesopsammic species, in other words, these very small slugs live in the interstitial spaces of marine sands.[2]
References
[edit]- ↑ Challis (1968). Trans. R. Soc. N. Z. (Zool.) 10: 193.
- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 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.