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Eulagisca Macnabi
''Eulagisca macnabi'' is a scale worm that occurs in the Antarctic Ocean, the Amundsen Sea and off the South Orkney Islands The South Orkney Islands are a group of islands in the Southern Ocean, about north-east of the tip of the Antarctic PeninsulaPettibone, Marian H. 1997. Revision of the scaleworm genus Eulagisca McIntosh (Polychaeta: Polynoidae) with the erection of the subfamily Eulagiscinae and the new genus Pareulagisca. Proceedings of the Biological Society of Washington, 110(4): 537–551. Description ''Eulagisa macnabi'' most likely has 15 pairs of elytra that have a marginal fringe of papillae. It is brown-pigmented, especially on bases of[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polynoidae
Polynoidae is a family of marine Polychaete worms known as "scale worms" due to the scale-like elytra on the dorsal surface. Almost 900 species are currently recognised belonging to 9 subfamilies and 167 genera. They are active hunters, but generally dwell in protected environments such as under stones. The group is widely distributed from shallow intertidal waters to hadal trenches. They are the most diverse group of polychaetes in terms of genus number and second most diverse in terms of species number which is almost 8% of all segmented worm species. Description Most Polynoidae species are short and flattened, but can reach as much as 20 cm in length and 10 cm width in '' Eulagisca gigantea'' and '' Eulagisca uschakovi''. Individuals are usually covered almost entirely by elytra, which can be shed and regenerated in many species. The elytra of some species are faintly bioluminescent, and leave glowing traces around the mouthparts of their predators, making those pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antarctic Ocean
The Southern Ocean, also known as the Antarctic Ocean, comprises the southernmost waters of the World Ocean, generally taken to be south of 60° S latitude and encircling Antarctica. With a size of , it is regarded as the second-smallest of the five principal oceanic divisions: smaller than the Pacific, Atlantic, and Indian oceans but larger than the Arctic Ocean. Over the past 30 years, the Southern Ocean has been subject to rapid climate change, which has led to changes in the marine ecosystem. By way of his voyages in the 1770s, James Cook proved that waters encompassed the southern latitudes of the globe. Since then, geographers have disagreed on the Southern Ocean's northern boundary or even existence, considering the waters as various parts of the Pacific, Atlantic, and Indian oceans, instead. However, according to Commodore John Leech of the International Hydrographic Organization (IHO), recent oceanographic research has discovered the importance of Southern C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amundsen Sea
The Amundsen Sea, an arm of the Southern Ocean off Marie Byrd Land in western Antarctica, lies between Cape Flying Fish (the northwestern tip of Thurston Island) to the east and Cape Dart on Siple Island to the west. Cape Flying Fish marks the boundary between the Amundsen Sea and the Bellingshausen Sea. West of Cape Dart there is no named marginal sea of the Southern Ocean between the Amundsen and Ross Seas. The Norwegian expedition of 1928–1929 under Captain Nils Larsen named the body of water for the Norwegian polar explorer Roald Amundsen while exploring this area in February 1929. The sea is mostly ice-covered, and the Thwaites Ice Tongue protrudes into it. The ice sheet which drains into the Amundsen Sea averages about in thickness; roughly the size of the state of Texas, this area is known as the Amundsen Sea Embayment (ASE); it forms one of the three major ice-drainage basins of the West Antarctic Ice Sheet. Embayment The ice sheet which drains into the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
South Orkney Islands
The South Orkney Islands are a group of islands in the Southern Ocean, about north-east of the tip of the Antarctic Peninsula''Antarctica: Secrets of the Southern Continent'' p. 122 David McGonigal, 2009 and south-west of . They have a total area of about . The islands are claimed both by Britain (as part of the since 1962, previously as a [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elytron (Annelida)
In annelids, elytra (; from Greek ἔλυτρον "sheath, cover"; singular: elytron ) are shield-like scales that are attached dorsally, one pair on each of a number of alternating segments and entirely or partly cover the dorsum. Elytra are modified dorsal cirri, and their number, size, location, and ornamentation are important taxonomic characters. The basal part of the elytra is known as the elytrophore; if (as is often the case) elytra are lost their presence is indicated by the elytrophore which is still present and visible. Annelids possessing elytra are also known as "scale worms". Possession of elytra is characteristic of the annelid suborder Aphroditiformia. Gallery File:Eunoe leiotentaculata lower res.jpg, A ''Eunoe leiotentaculata'' specimen showing its 15 pairs of elytra. File:Euphione sp. dorsal.jpg, ''Euphione ''Euphione'' is a genus of polychaetes belonging to the family Polynoidae. The species of this genus are found in Australia, Malesia Malesia is a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parapodia
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 notoch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prostomium
The prostomium (From Ancient Greek, meaning "before the mouth"; plural: prostomia; sometimes also called the "acron") is the cephalized first body segment in an annelid worm's body at the anterior end. It is in front of (but does not include) the mouth, being usually a small shelf- or lip-like extension over the dorsal side of the mouth. The prostomium together with the peristomium, which includes the mouth and pharynx, make up the annelid head. Description The prostomium is part of the head and holds at least part of the brain and often bears sensory structures such as the eyes, antennae and palps. It may function like a kind of overlip when the animal is feeding. The prostomium bears many important taxonomic characters and its shape and composition are important for annelid systematics. In addition to the eyes, antennae and palps, the prostomium can possess appendages such as tentacles or cirri. Moreover, some polychaete Polychaeta () is a paraphyletic class of gener ... [...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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
