''Roboastra tentaculata'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

sea slug Sea slug is a common name for some marine invertebrates with varying levels of resemblance to terrestrial slugs. Most creatures known as sea slugs are gastropods, i.e. they are sea snails (marine gastropod mollusks) that over evolutionary time ...

, a polycerid

nudibranch Nudibranchs () are a group of soft-bodied marine gastropod molluscs which shed their shells after their larval stage. They are noted for their often extraordinary colours and striking forms, and they have been given colourful nicknames to match, ...

, a marine gastropod mollusc in the family

Polyceridae The Polyceridae are a taxonomic family of sea slugs, dorid nudibranchs, marine gastropod mollusks within the superfamily Polyceroidea. Taxonomy The family Polyceridae is classified within the clade Doridacea, itself belonging to the clade Euc ...

Distribution

This species was described from

Guam Guam (; ch, Guåhan ) is an organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. It is the westernmost point and territory of the United States (reckoned from the geographic cent ...

Etymology

''Tentaculata'' is used to describe ''Roboastra tentaculata'' due to the presence of oral tentacles. Oral tentacles allow sea slugs to move and obtain information from the environment.

Phylogeny

In order for phylogenetic integrity, ''Roboastra tentaculata'' was moved into ''Roboastra'' from the genus ''Tambja''.

Morphology

The bulk of the sea slug body is green, along with bright yellow or orange stripes outlined with brown. Two green

rhinophores A rhinophore is one of a pair of chemosensory club-shaped, rod-shaped or ear-like structures which are the most prominent part of the external head anatomy in sea slugs, marine gastropod opisthobranch mollusks such as the nudibranchs, sea ha ...

with lamellae and rhinophoral cases are noticeable. This sea slug has green gills of two different sizes. Bright green oral tentacles are also found on the back of the organism, opposite of a straight green foot located on the bottom. Also present is a radula with smooth and large teeth. The digestive system is composed of salivary glands, an esophagus and an oral tube. ''R. tentaculata'' also have three reproductive duct structures; a hermaphroditic, vaginal and uterine duct. The first duct is

hermaphroditic In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many taxonomic groups of animals (mostly invertebrates) do not have s ...

with an

ampulla An ampulla (; ) was, in Ancient Rome, a small round vessel, usually made of glass and with two handles, used for sacred purposes. The word is used of these in archaeology, and of later flasks, often handle-less and much flatter, for holy water or ...

vas deferens The vas deferens or ductus deferens is part of the male reproductive system of many vertebrates. The ducts transport sperm from the epididymis to the ejaculatory ducts in anticipation of ejaculation. The vas deferens is a partially coiled tube ...

and a spiked penis. The second tract is composed of a small vaginal tube and a bursa copulatrix. The third duct contains a uterine tube and one

oviduct The oviduct in mammals, is the passageway from an ovary. In human females this is more usually known as the Fallopian tube or uterine tube. The eggs travel along the oviduct. These eggs will either be fertilized by spermatozoa to become a zygote, o ...

References

{{taxonbar, from=Q21305856 Polyceridae Gastropods described in 2005