The radula is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus. The radula is unique to the mollusks, and is found in every class of mollusk except the bivalves, which instead use cilia, waving filaments that bring minute organisms to the mouth.
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 that over evolutionary time have either completely lost their shells, or have seemingly lost their shells due to having a greatly reduced or internal shell. The name "sea slug" is most often applied to nudibranchs, as well as to a paraphyletic set of other marine gastropods without obvious shells.
Opisthobranchs is a now informal name for a large and diverse group of specialized complex gastropods which used to be united in the subclass Opisthobranchia. That taxon is no longer considered to represent a monophyletic grouping.
The order Cephalaspidea, also known as the headshield slugs and bubble snails, is a major taxon of sea slugs and bubble snails, marine gastropod mollusks within the larger clade Euopisthobranchia. Bubble shells is another common name for these families of marine gastropods, some of which have thin bubble-like shells. This clade contains more than 600 species.
Euthyneura is a taxonomic infraclass of snails and slugs, which includes species exclusively from marine, aquatic and terrestrial gastropod mollusks in the clade Heterobranchia.
Acochlidiacea, common name acochlidians, are a taxonomic clade of very unusual sea snails and sea and freshwater slugs, aquatic gastropod mollusks within the large clade Heterobranchia. Acochlidia is a variant spelling.
Parhedylidae are a taxonomic family of sea slugs, marine gastropod mollusks in the superfamily Parhedyloidea.
Strubellia paradoxa is a species of freshwater slug, a shell-less freshwater gastropod, an aquatic gastropod mollusk within the clade Acochlidiacea.
Pseudunela cornuta is a species of minute sea slug, an acochlidian, a shell-less marine and temporarily brackish gastropod mollusk in the family Pseudunelidae. Adults are about 3 mm long and live in the spaces between sand grains.
Acochlidium is a genus of freshwater slugs, an aquatic gastropod molluscs in the family Acochlidiidae.
Pseudunela is a genus of minute sea slugs, acochlidians, shell-less marine or temporary brackish or brackish gastropod mollusks in the clade Acochlidiacea.
Aiteng ater is a species of sea slug, a marine gastropod mollusc in the family Aitengidae. The specific name ater is from the Latin language and means black, in reference to the appearance of the slug on the mud.
Aiteng is a genus comprising three species of sea slug, A. ater and A. mysticus being found in intertidal zones while A. marefugitus is fully terrestrial. Aiteng is the only genus in the family Aitengidae. The generic name Aiteng is derived from the name of a black puppet Ai Theng, which is one of the shadow play puppets in southern Thailand.
Parhedyle cryptophthalma is a species of sea slug, an acochlidian, a shell-less marine gastropod mollusk in the family Microhedylidae.
Aiteng mysticus is a species of sea slug in the family Aitengidae, found around Hisamatsu, Miyako-jima, Okinawa, Japan. Morphologically it clearly belongs to the Aitengidae, but it shows differences to Aiteng ater at genus or species level. Its affinity to Aiteng ater is confirmed by comparison of the mitochondrial 16S rRNA sequences.
Pontohedyle verrucosa is a species of sea slug, an acochlidian, a shell-less marine gastropod mollusc in the family Microhedylidae.
Pontohedyle milaschewitchii is a species of sea slug, an acochlidian, a shell-less marine gastropod mollusk in the family Microhedylidae.
Pseudunela viatoris is a species of sea slug, an acochlidian, a shell-less marine gastropod mollusk in the family Pseudunelidae.
Pseudunela marteli is a species of sea slug, an acochlidian, a shell-less marine gastropod mollusk in the family Pseudunelidae.
Aiteng marefugitus is a species of fully terrestrial sea slug found only on the Ulong Island of Palau. The species name is derived from latin, meaning "fled from the sea".
