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Echiura
The Echiura, or spoon worms, are a small group of ocean, marine animals. Once treated as a separate phylum, they are now considered to belong to Annelida. Annelids typically have their bodies divided into Segmentation (biology), segments, but echiurans have secondarily lost their segmentation. The majority of echiurans live in burrows in soft sediment in shallow water, but some live in rock crevices or under boulders, and there are also deep sea forms. More than 230 species have been described. Spoon worms are cylindrical, soft-bodied animals usually possessing a non-retractable proboscis which can be rolled into a scoop-shape to feed. In some species the proboscis is ribbon-like, longer than the trunk and may have a forked tip. Spoon worms vary in size from less than a centimetre in length to more than a metre. Most are deposit feeders, collecting detritus from the sea floor. Fossils of these worms are seldom found and the earliest known fossil specimen is from the Darriwilian, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annelida
The annelids (), also known as the segmented worms, are animals that comprise the phylum Annelida (; ). The phylum contains over 22,000 extant species, including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments. The annelids are Symmetry in biology, bilaterally symmetrical, Triploblasty, triploblastic, coelomate, invertebrate organisms. They also have Parapodium, parapodia for locomotion. Most textbooks still use the traditional division into polychaetes (almost all marine), oligochaetes (which include earthworms) and leech-like species. Cladistics, Cladistic research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Siboglinidae, Pogonophora, Echiura and Sipuncula, previ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annelid
The annelids (), also known as the segmented worms, are animals that comprise the phylum Annelida (; ). The phylum contains over 22,000 extant species, including ragworms, earthworms, and leeches. The species exist in and have adapted to various ecologies – some in marine environments as distinct as tidal zones and hydrothermal vents, others in fresh water, and yet others in moist terrestrial environments. The annelids are bilaterally symmetrical, triploblastic, coelomate, invertebrate organisms. They also have parapodia for locomotion. Most textbooks still use the traditional division into polychaetes (almost all marine), oligochaetes (which include earthworms) and leech-like species. Cladistic research since 1997 has radically changed this scheme, viewing leeches as a sub-group of oligochaetes and oligochaetes as a sub-group of polychaetes. In addition, the Pogonophora, Echiura and Sipuncula, previously regarded as separate phyla, are now regarded as sub-grou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urechis Caupo
''Urechis caupo'' is a species of Echiura, spoon worm in the family Urechidae, commonly known as the innkeeper echiuran, the fat innkeeper worm (because their tunnels often contain other animals), the innkeeper worm, or the penis fish. It is found in shallow water on the west coast of North America, between southern Oregon and Baja California, where it forms a U-shaped burrow in the sediment and feeds on plankton using a mucus net. Description ''Urechis caupo'' is a plump, unsegmented, cylindrical pink worm growing to a length of up to 7 inches, with 5.5 inches being a more typical length. There are a pair of setae (bristles) on the ventral surface at the anterior end, and a distinctive ring of about ten setae around the anus at the posterior end. The proboscis is short. Distribution and habitat Shallow water in the northeastern Pacific Ocean is the habitat of ''U. caupo''; its range extends from southern Oregon to northern Baja California. It lives in a burrow in muddy sand in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Echiurus Echiurus
''Echiurus echiurus'' is a species of spoon worm in the family Echiuridae. It is found in the North Atlantic Ocean and a subspecies is found in Alaska. It burrows into soft sediment and under boulders and stones in muddy places. Description This spoon worm has a roughly cylindrical trunk between long. At the anterior end of the trunk, just beside the mouth, a scoop-shaped proboscis about long extends forward. The trunk has about 22 rings of papillae, a ring of larger papillae alternating with several rings of smaller papillae. A pair of hooked chaetae (chitinous bristles) is borne just behind the mouth on the underside of the worm and there are two rings of chaetae on the posterior end of the trunk, near the anus. Internally, the rectum is partially obscured by two long anal diverticula with ciliated funnels. Externally, the trunk is greyish-brown while the proboscis is orange with brownish streaks. Distribution ''Echiurus echiurus'' has a holarctic distribution, extending s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ikedidae
Ikedidae is a family of spoon worms in the suborder Bonelliida. It is a monotypic family, the only genus being ''Ikeda''. These worms burrow into soft sediment on the seabed. Examination of the original material of '' Ikeda taenoides'' by Teruaki Nishikawa in 2002 showed that the longitudinal muscle layer lay between the circular layer and the oblique layer, as in all other echiurans, throwing the validity of the family Ikedidae into doubt. Nishikawa advocates that the family be regarded as a junior synonym of Echiuridae. Species The World Register of Marine Species recognises the following species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ... in the genus:- *'' Ikeda pirotansis'' ( Menon & DattaGupta, 1962) *'' Ikeda taenioides'' ( Ikeda, 1904) References Echiura ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sipuncula
The Sipuncula or Sipunculida (common names sipunculid worms or peanut worms) is a class containing about 162 species of marine annelid worms, that have secondarily lost their segmentation. Sipuncula was once considered a phylum of unsegmented worms, but was demoted to a class of Annelida, based on recent molecular work. Sipunculans vary in size but most species are under in length. The body is divided into an unsegmented, bulbous trunk and a narrower, anterior Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position pro ... section, called the "introvert", which can be retracted into the trunk. The mouth is at the tip of the introvert and is surrounded in most groups by a ring of short tentacles. With no hard parts, the body is flexible and mobile. Although found in a range of habitats thro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Burrow Fossil
Burrow fossils are the remains of burrows - holes or tunnels excavated into the ground or seafloor - by animals to create a space suitable for habitation, temporary refuge, or as a byproduct of locomotion preserved in the rock record. Because burrow fossils represent the preserved byproducts of behavior rather than physical remains, they are considered a kind of trace fossil. One common kind of burrow fossil is known as '' Skolithos'', and the similar '' Trypanites'', '' Ophiomorpha'' and ''Diplocraterion''. Vertebrate burrows Fish burrows Fossil Lungfish burrows are preserved in the Rocky Point Member of the Chinle Formation in Canyonlands National Park. Invertebrate burrows Examples are ''Treptichnus pedum'' and '' Arenicolites franconicus''. See also * Paleoburrow * Trace fossil A trace fossil, also called an ichnofossil (; ), is a fossil record of biological activity by lifeforms, but not the preserved remains of the organism itself. Trace fossils contrast with b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pennsylvanian (geology)
The Pennsylvanian ( , also known as Upper Carboniferous or Late Carboniferous) is, on the International Commission on Stratigraphy, ICS geologic timescale, the younger of two period (geology), subperiods of the Carboniferous Period (or the upper of two system (stratigraphy), subsystems of the Carboniferous System). It lasted from roughly . As with most other geochronology, geochronologic units, the stratum, rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain by a few hundred thousand years. The Pennsylvanian is named after the U.S. state of Pennsylvania, where the coal Bed (geology), beds of this age are widespread. The division between Pennsylvanian and Mississippian (geology), Mississippian comes from North American stratigraphy. In North America, where the early Carboniferous beds are primarily marine limestones, the Pennsylvanian was in the past treated as a full-fledged geologic period between the Mississippian ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mazon Creek Fossil Beds
The Mazon Creek fossil beds are a conservation ' found near Morris, in Grundy County, Illinois. The fossils are preserved in ironstone concretions, formed approximately in the mid- Pennsylvanian epoch of the Carboniferous period. These concretions frequently preserve both hard and soft tissues of animal and plant materials, as well as many soft-bodied organisms that do not normally fossilize. The quality, quantity and diversity of fossils in the area, known since the mid-nineteenth century, make the Mazon Creek ' important to paleontologists attempting to reconstruct the paleoecology of the sites. The locality was declared a National Historic Landmark in 1997.. Geology The Mazon Creek fossils are found in the Upper Carboniferous Francis Creek Shale. The type locality is the Mazon River (or Mazon Creek), a tributary of the Illinois River near Morris, Grundy County, Illinois. The 25 to 30 meters of shale were formed approximately , during the Pennsylvanian period. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Capitellidae
Capitellidae is a polychaete worm family in the subclass Scolecida Scolecida is an Infraclass (biology), infraclass of polychaete worms. Scolecids are mostly unselective Detritivore, deposit feeders on marine detritus. Characteristics Scolecids have Parapodium, parapodia with rami that are all alike. The pros .... Genera * '' Abyssocapitella'' * '' Amastigos'' * '' Anotomastus'' * '' Baldia'' * '' Barantolla'' * '' Branchiocapitella'' * '' Capitella'' * '' Capitellethus'' * '' Capitobranchus'' * '' Dasybranchetus'' * '' Dasybranchus'' * '' Decamastus'' * '' Ditrocha'' * '' Dodecaseta'' * '' Eunotomastus'' * '' Heteromastides'' * '' Heteromastus'' * '' Leiocapitella'' * '' Leiocapitellides'' * '' Leiochrides'' * '' Leiochrus'' * '' Lumbricomastus'' * '' Mastobranchus'' * '' Mediomastus'' * '' Neoheteromastus'' * '' Neomediomastus'' * '' Neonotomastus'' * '' Neopseudocapitella'' * '' Nonatus'' * '' Notodasus'' * '' Notomastus'' * '' Octocapitella'' * '' Paracapitella'' * '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holothuria
''Holothuria'' is the type genus of the marine animal family Holothuriidae, part of the class Holothuroidea, commonly known as sea cucumbers. Members of the genus are found in coastal waters in tropical and temperate regions. They are soft-bodied, limbless invertebrates which dwell on the ocean floor and are usually detritivores. They resemble a cucumber in form. The genus contains some species that are harvested and sold as food. Species The World Register of Marine Species recognizes 163 species in 19 subgenera of ''Holothuria'': * Subgenus ''Acanthotrapeza'' ** '' Holothuria coluber'' ** '' Holothuria kubaryi'' ** '' Holothuria pyxis'' ** '' Holothuria tripilata'' * Subgenus ''Cystipus'' ** '' Holothuria casoae'' ** '' Holothuria cubana'' ** '' Holothuria dura'' ** '' Holothuria hartmeyeri'' ** '' Holothuria inhabilis'' ** '' Holothuria jousseaumei'' ** '' Holothuria mammosa'' ** '' Holothuria occidentalis'' ** '' Holothuria pseudofossor'' ** '' Holoth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
