|
Rhabdopleurida
Rhabdopleurida is one of three orders in the class Pterobranchia, which are small, worm-shaped animals, are the only surviving graptolites. Members belong to the hemichordates. Species in this order are sessile, colonial, connected with a stolon, living in clear water and secrete tubes called tubarium. They have a single gonad, the gill slits are absent and the collar has two tentaculated arms. ''Rhabdopleura'' is the best studied pterobranch in developmental biology. ''Rhabdopleura'' is the only extant graptolite. Taxonomy This small order is monotypic. It has only a single extant genus, containing four to six living species. Order Rhabdopleurida Fowler 1892 * Family Rhabdopleuridae Harmer 1905 ** Genus ''Rhabdopleura'' Allman 1869 *** ''Rhabdopleura annulata'' Norman 1921 — Indo-Pacific region *** '' Rhabdopleura compacta'' Hincks 1880 — Atlantic *** ''Rhabdopleura normani'' Allmann, 1869 — Atlantic and parts of the Pacific *** ''Rhabdopleura recondita'' Beli, Cameron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graptolites
Graptolites are a group of colonial animals, members of the subclass Graptolithina within the class Pterobranchia. These filter-feeding organisms are known chiefly from fossils found from the Middle Cambrian (Miaolingian, Wuliuan) through the Lower Carboniferous ( Mississippian). A possible early graptolite, ''Chaunograptus'', is known from the Middle Cambrian. Recent analyses have favored the idea that the living pterobranch ''Rhabdopleura'' represents an extant graptolite which diverged from the rest of the group in the Cambrian. Fossil graptolites and ''Rhabdopleura'' share a colony structure of interconnected zooids housed in organic tubes (theca) which have a basic structure of stacked half-rings (fuselli). Most extinct graptolites belong to two major orders: the bush-like sessile Dendroidea and the planktonic, free-floating Graptoloidea. These orders most likely evolved from encrusting pterobranchs similar to ''Rhabdopleura''. Due to their widespread abundance, plantkonic l ... [...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] |
Rhabdopleura Normani
''Rhabdopleura normani'' is a small, marine species of worm-shaped animal known as a pterobranch. It is a sessile suspension feeder, lives in clear water, and secretes tubes on the ocean floor. Description This species grows in colonies. Each individual achieves a length of 0.5 mm, with a total colony length of approximately 20 mm. Located on the tentacles are lateral, frontal, and frontolateral ciliary bands. These are 8-13 μm in length and composed of cilia. In specimens collected in Bermuda, ciliated perforations were found. These ran down the length of the arms, in particular, between the bases of other tentacles laying adjacent. Distribution ''Rhabdopleura normani'' is widely distributed along the coastlines of the Bering Sea, Norwegian Sea, Atlantic Ocean, and Mediterranean Sea. It has also been found in Bermuda. Reported locations include:Beli E, Aglieri G, Strano F, Maggioni D, Telford MJ, Piraino S, Cameron CB (2018) The zoogeography of extant rhabdopleur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhabdopleura
''Rhabdopleura'' is a genus of colonial sessile hemichordates belonging to the Pterobranchia class. As one of the oldest living genera with a fossil record dating back to the Middle Cambrian, it is also considered to be the only living genus of graptolites. ''Rhabdopleura'' is the best studied pterobranch in developmental biology. Research in the 2010s by Jörg Maletz and other paleontologists and biologists have demonstrated that ''Rhabdopleura'' is an extant graptolite. Species List of species from Maletz (2014): ;Living species The genus ''Rhabdopleura'' contains at least five living species. * ''Rhabdopleura annulata'' Norman 1921 — Indo-Pacific region * '' Rhabdopleura compacta'' Hincks 1880 — Atlantic * ''Rhabdopleura normani'' Allmann, 1869 — Atlantic and parts of the Pacific * ''Rhabdopleura recondita'' Beli, Cameron and Piraino, 2018 — Mediterranean * ''Rhabdopleura striata'' Schepotieff 1909 — Pacific (Sri Lanka) ;''Nomen dubium'' (doubtful) * ''Rhabdopleu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphenothallus
''Sphenothallus'' is a problematic extinct genus lately attributed to the conulariids. It was widespread in shallow marine environments during the Paleozoic. Occurrence ''Sphenothallus'' is represented in the Cambrian period in the Kaili biota and the Mount Stephen trilobite beds, where it co-occurs with the similar organisms '' Cambrorhythium'' and '' Byronia''. It is known in younger strata in Canada and the US, surviving at least until the Mississippian. Ecology ''Sphenothallus'' lived in groups as an opportunist in environments from hardground Carbonate hardgrounds are surfaces of synsedimentarily cemented carbonate layers that have been exposed on the seafloor (Wilson and Palmer, 1992). A hardground is essentially, then, a lithified seafloor. Ancient hardgrounds are found in limestone ...s to soft mud, even if depleted in oxygen. It probably dispersed via larvae. Notes References External links * {{Taxonbar, from=Q7576667 Burgess Shale fossils Stau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rhabdotubus
The Lower-Middle Cambrian animal ''Rhabdotubus'' is the earliest known pterobranch. It bears strong similarity to the graptolite Graptolites are a group of colonial animals, members of the subclass Graptolithina within the class Pterobranchia. These filter-feeding organisms are known chiefly from fossils found from the Middle Cambrian ( Miaolingian, Wuliuan) through t ...s - indeed for some time it was misclassified as a dendroid graptolite. References Cambrian invertebrates Prehistoric hemichordate genera Fossils of Sweden {{Hemichordate-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
