Paraganitus ellynnae
| Paraganitus ellynnae | |
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| Genus: | Paraganitus Challis, 1968[2]
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| Species: | P. ellynnae
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| Binomial name | |
| Paraganitus ellynnae Challis, 1968
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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.[1]
Description
[edit]Paraganitus ellynnae is smaller than 5 mm and is externally symmetric.[1] It has no shell in adults, and no operculum in adults.[1] It has also no head shield and no posterior shield.[1] It is able to partially retract parts of its anterior body into a temporal visceral cavity.[1] The visceral sac is largely separated from the rest of the body.[1] The mantle is robust.[1] The visceral hump is conical.[1] The tail is short and pointed.[1] The foot is narrow, the anterior foot edge is rounded and it can crawl on the whole foot.[1] It has no mantle cavity.[1] It has elongated/pointed rhinophores.[1] Like all acochlidians, it has oral (= labial) tentacles.[1] Paraganitus ellynnae has long and slightly recurved oral tentacles.[1] Oral tentacle nerves have been present in all examined acochlidians to date, but those nerves were not examined in this species.[1]
Like all acochlidians, it lacks plicate gills.[1] The position of the anus is unknown.[1] It has no calcareous spicules, but it has integumental concrements.[1] It has no keel on the visceral hump.[1]
It has aggregations of precerebral ‘accessory ganglia’.[1] It has no eyes.[1] The presence or absence of Hancock's organ is unknown.[1] It has prepharyngeal CNS as is the case in all other acochlidians.[1]
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.[1]
References
[edit]- ^ a b c d e f g h i j k l m n o p q r s t u v w x y 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.
- ^ Challis (1968). Trans. R. Soc. N. Z. (Zool.) 10: 193.