|
Enteropneusta
The acorn worms or Enteropneusta are a hemichordate class of invertebrates consisting of one order of the same name. The closest non-hemichordate relatives of the Enteropneusta are the echinoderms. There are 111 known species of acorn worm in the world, the main species for research being '' Saccoglossus kowalevskii''. Two families—Harrimaniidae and Ptychoderidae—separated at least 370 million years ago. Until recently, it was thought that all species lived in the sediment on the seabed, subsisting as deposit feeders or suspension feeders. However, the early 21st century has seen the description of a new family, the Torquaratoridae, evidently limited to the deep sea, in which most of the species crawl on the surface of the ocean bottom and alternatively rise into the water column, evidently to drift to new foraging sites. It is assumed that the ancestors of acorn worms used to live in tubes like their relatives Pterobranchia, but that they eventually started to live a safer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Torquaratoridae
Torquaratoridae (Latin for "neck plow") is a family of acorn worms ( Hemichordata) that lives in deep waters between 350 to 4000 meters (the species Tergivelum baldwinae has been found 4100 meters below the surface). They can grow up to three feet in length and have semitransparent gelatinous bodies, often brightly colored. Cilia on their underside are used to glide over the ocean floor at about three inches per hour, while detritus is sucked into their gut, leaving behind a constant trail of feces. When deciding to move to new feeding locations, they empty their gut and drift over the bottom, aided by an excreted balloon of mucus, before they let themselves down somewhere else. One species (''Coleodesmium karaensis'') has been shown to care for the offspring by bearing about a dozen embryos surrounded by a thin membrane in shallow depressions on the surface of the mother's pharyngeal region. The proboscis skeleton is reduced to a small medial plate in one genus, while it is ab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Saccoglossus Kowalevskii
Hemichordata is a phylum which consists of triploblastic, enterocoelomate, and bilaterally symmetrical marine deuterostome animals, generally considered the sister group of the echinoderms. They appear in the Lower or Middle Cambrian and include two main classes: Enteropneusta (acorn worms), and Pterobranchia. A third class, Planctosphaeroidea, is known only from the larva of a single species, ''Planctosphaera pelagica''. The class Graptolithina, formerly considered extinct, is now placed within the pterobranchs, represented by a single living genus ''Rhabdopleura''. Acorn worms are solitary worm-shaped organisms. They generally live in burrows (the earliest secreted tubes) and are deposit feeders, but some species are pharyngeal filter feeders, while the family Torquaratoridae are free living detritivores. Many are well known for their production and accumulation of various halogenated phenols and pyrroles. Pterobranchs are filter-feeders, mostly colonial, living in a colla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harrimaniidae
Harrimaniidae is a basal family of acorn worms. A taxonomic revision was undertaken in 2010, and a number of new genera and species found in the Eastern Pacific were described. In this family the development is direct without tornaria larva, and circular muscle fibers in their trunk is missing. There is some indication that Stereobalanus may be a separate basal acorn worm lineage, sister to all remaining acorn worms. Species The following genera and species are listed in the World Register of Marine Species: . Retrieved October 17, 2011. *'' Harrimania [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Balanoglossus 2
''Balanoglossus'' is a genus of ocean-dwelling acorn worms (Enteropneusta). It has zoological importance because, being hemichordates, they are an "evolutionary link" between invertebrates and vertebrates. ''Balanoglossus'' is a deuterostome, and resembles the sea squirts (Ascidiacea) in that it possesses branchial openings, or "gill slits". It has a notochord in the upper part of the body and has no nerve chord. It does have a stomochord, however, which is a gut chord within the collar. Their heads may be as small as per 2.5 mm (1/10 in) or as large as 5 mm (1/5 in). Discovery The discovery of gill-slits in this animal by Alexander Kovalevsky (1865) led to the creation of the class Enteropneusta by Karl Gegenbaur (1870). Classification William Bateson (1885) originally included them in phylum Chordata. Hyman (1959), however, placed them near Echinodermata and gave Hemichordata a status of an independent phylum. Habitat Balanoglossus is a tuberculos (bur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Balanoglossus 3
''Balanoglossus'' is a genus of ocean-dwelling acorn worms (Enteropneusta). It has zoological importance because, being hemichordates, they are an "evolutionary link" between invertebrates and vertebrates. ''Balanoglossus'' is a deuterostome, and resembles the sea squirts (Ascidiacea) in that it possesses branchial openings, or "gill slits". It has a notochord in the upper part of the body and has no nerve chord. It does have a stomochord, however, which is a gut chord within the collar. Their heads may be as small as per 2.5 mm (1/10 in) or as large as 5 mm (1/5 in). Discovery The discovery of gill-slits in this animal by Alexander Kovalevsky (1865) led to the creation of the class Enteropneusta by Karl Gegenbaur (1870). Classification William Bateson (1885) originally included them in phylum Chordata. Hyman (1959), however, placed them near Echinodermata and gave Hemichordata a status of an independent phylum. Habitat Balanoglossus is a tuberculos (bur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Balanoglossus Gigas
''Balanoglossus'' is a genus of ocean-dwelling acorn worms (Enteropneusta). It has zoological importance because, being hemichordates, they are an "evolutionary link" between invertebrates and vertebrates. ''Balanoglossus'' is a deuterostome, and resembles the sea squirts (Ascidiacea) in that it possesses branchial openings, or "gill slits". It has a notochord in the upper part of the body and has no nerve chord. It does have a stomochord, however, which is a gut chord within the collar. Their heads may be as small as per 2.5 mm (1/10 in) or as large as 5 mm (1/5 in). Discovery The discovery of gill-slits in this animal by Alexander Kovalevsky (1865) led to the creation of the class Enteropneusta by Karl Gegenbaur (1870). Classification William Bateson (1885) originally included them in phylum Chordata. Hyman (1959), however, placed them near Echinodermata and gave Hemichordata a status of an independent phylum. Habitat Balanoglossus is a tuberculos (bur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ptychoderidae
Ptychoderidae is a family of acorn worms. Genera and species The World Register of Marine Species lists the following: World Register of Marine Species. Retrieved 2011-10-17. Balanoglossus Contains the following species: * '''' (Spengel, 1893) * '' Balanoglossus aurantiacus'' (Girard, 1853) * '''' (Hill, 1894) * '' ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Meioglossus
''Meioglossus psammophilus'' is a species of acorn worm in the family Harrimaniidae, the only known species of the genus ''Meigolossus''. It inhabits the Western Caribbean and Bermuda. The name of the species derives from two Greek words; ''psammon'' and ''philos'' which in translation means ''friend of the sands'' in reference to adult stage of species' lifestyle. The length of the species is . It is able to reproduce asexually through paratomy Paratomy is a form of asexual reproduction in animals where the organism splits in a plane perpendicular to the antero-posterior axis and the split is preceded by the "pregeneration" of the anterior structures in the posterior portion. The developi .... References Animals described in 2012 Articles containing video clips Enteropneusta {{Hemichordate-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spengeliidae
Spengelidae is a family of worms belonging to the class Enteropneusta The acorn worms or Enteropneusta are a hemichordate class of invertebrates consisting of one order of the same name. The closest non-hemichordate relatives of the Enteropneusta are the echinoderms. There are 111 known species of acorn worm in the ..., order unknown. Genera: * '' Glandiceps'' Spengel, 1891 * '' Mazoglossus'' Bardack, 1997 * '' Schizocardium'' Spengel, 1893 * '' Spengelia'' Willey, 1898 * '' Willeyia'' Punnett, 1903 References {{Taxonbar, from=Q3813791 Enteropneusta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spartobranchus Tenuis
Spartobranchus tenuis is an extinct species of acorn worms (Enteropneusta). It existed in the Middle Cambrian (505 million years ago). Petrified mark animals were found in British Columbia, Canada in the Burgess Shale formation. It is similar to the modern representatives of the family Harrimaniidae, distinguished by branching fiber tubes. It is a believed predecessor of Pterobranchia Pterobranchia is a class of small worm-shaped animals. They belong to the Hemichordata, and live in secreted tubes on the ocean floor. Pterobranchia feed by filtering plankton out of the water with the help of cilia attached to tentacles. The ..., but this species is intermediate between these two classes. Studies show that these tubes were lost in the line leading to modern acorn worm, but remained in the extinct graptolites and saving still perystozyabernyh. Description Detailed analysis shows that ''Spartobranchus tenuis'' had a flexible body consisting of short proboscis, collar and narr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pterobranchia
Pterobranchia is a class of small worm-shaped animals. They belong to the Hemichordata, and live in secreted tubes on the ocean floor. Pterobranchia feed by filtering plankton out of the water with the help of cilia attached to tentacles. There are about 25 known living pterobranch species in three genera, which are ''Rhabdopleura'', '' Cephalodiscus'', and '' Atubaria''. On the other hand, there are several hundred extinct genera, some of which date from the Cambrian Period. The class Pterobranchia was established by Ray Lankester in 1877. It contained, at that time, the single genus ''Rhabdopleura''. ''Rhabdopleura'' was at first regarded as an aberrant polyzoon, but when the ''Challenger'' report on '' Cephalodiscus'' was published in 1887, it became clear that ''Cephalodiscus'', the second genus now included in the order, had affinities with the Enteropneusta. Electron microscope studies have suggested that pterobranchs belong to the same clade as the extinct grapto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereobalanus
''Stereobalanus'' is a genus of acorn worms belonging to the family Harrimaniidae Harrimaniidae is a basal family of acorn worms. A taxonomic revision was undertaken in 2010, and a number of new genera and species found in the Eastern Pacific were described. In this family the development is direct without tornaria larva, and .... The species of this genus are found in Europe and Northern America. Species: *'' Stereobalanus canadensis'' *'' Stereobalanus willeyi'' References {{Taxonbar, from=Q3824273 Enteropneusta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Enteropneusta")
