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Aciculidae
The Aciculidae are a family of minute land snails which have opercula (an operculum is a little door that closes the shell when the animal retracts into it). In other words, Aciculidae are terrestrial operculate gastropods. Even though Aciculidae are land snails, they live in rather wet conditions, among mosses and dead leaves and they have sometimes been described as " winkles come ashore". Taxonomy Previously this family was placed in the infraorder Littorinimorpha, in the suborder Hypsogastropoda in the order Sorbeoconcha in the taxonomy of the Gastropoda by Ponder & Lindberg (1997). The family Aciculidae is in the informal group Architaenioglossa, belonging to the clade Caenogastropoda, (according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005). This family has no subfamilies according to the taxonomy of the Gastropoda by Bouchet & Rocroi, 2005. In the Taxonomy of the Gastropoda (Bouchet et al., 2017), it was placed under Cyclophoroidea. Genera Genera wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaeta
A chaeta or cheta (from Greek χαίτη “crest, mane, flowing hair"; plural: chaetae) is a chitinous bristle or seta found in annelid worms, (although the term is also frequently used to describe similar structures in other invertebrates such as arthropods). Polychaete annelids, ('polychaeta' literally meaning "many bristles") are named for their chaetae. In Polychaeta, chaetae are found as bundles on the parapodia, paired appendages on the side of the body. The chaetae are epidermal extracellular structures, and clearly visible in most polychaetes. They are probably the best studied structures in these animals. Use in taxonomy and identification The ultrastructure of chaetae is fundamentally similar for all taxa but there is vast diversity in chaetal morphology. Moreover, chaetae bear precise characters for determination of species and taxonomic assessment. The shape, absolute and relative size, number, position, ornamentation and type are important taxonomic characters a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parapodium
In invertebrates, the term parapodium ( Gr. ''para'', beyond or beside + ''podia'', feet; plural: parapodia) refers to lateral outgrowths or protrusions from the body. Parapodia are predominantly found in annelids, where they are paired, unjointed lateral outgrowths that bear the chaetae. In several groups of sea snails and sea slugs, 'parapodium' refers to lateral fleshy protrusions. __TOC__ Annelid parapodia Most species of polychaete annelids have paired, fleshy parapodia which are segmentally arranged along the body axis. Parapodia vary greatly in size and form, reflecting a variety of functions, such as gas exchange, anchorage, protection and locomotion. General description Parapodia in polychaetes can be uniramous (consisting of one lobe or ramus) but are usually biramous (two lobes or rami). In the latter case, the dorsal lobes are called notopodia and the ventral lobes neuropodia. Both neuropodia and notopodia may possess a bundle of chaetae (neurochaetae and notochaet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polychaeta
Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. More than 10,000 species are described in this class. Common representatives include the lugworm (''Arenicola marina'') and the sandworm or clam worm ''Alitta''. Polychaetes as a class are robust and widespread, with species that live in the coldest ocean temperatures of the abyssal plain, to forms which tolerate the extremely high temperatures near hydrothermal vents. Polychaetes occur throughout the Earth's oceans at all depths, from forms that live as plankton near the surface, to a 2- to 3-cm specimen (still unclassified) observed by the robot ocean probe ''Nereus'' at the bottom of the Challenger Deep, the deepest known spot in the Earth's oceans. Only 168 species (less than 2% of all polychaetes) are known from f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctonoe Sp
''Arctonoe'' is a genus of worms belonging to the family Polynoidae. They are commonly known as "scale worms". Members of this genus predominantly occur in shallow (50 metres or less) waters of the northeast Pacific Ocean and often live as commensals of other marine invertebrates, frequently echinoderms but sometimes molluscs or other polychaetes. Description Arctonoe have long bodies, with 100 or more segments and numerous pairs of smooth translucent scales (elytra) on several of the segments. The first segment (prostomium), which contains the mouth, is rounded and smooth; on its side it has antennae pointing away from the body. Parapodia are found along the body with both dorsal (notopodial) and ventral (neuropodial) acicula penetrating epidermis. The notochaetae are few in number and more slender than the neurochaetae both notochaetae and neurochaetae have minutely notched tips (see Hanley, 1989 for detailed diagnosis). Species The following species of ''Arctonoe'' are recognis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
