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Pleistoannelida
Pleistoannelida is a group of annelid worms that comprises the vast majority of the diversity in phylum Annelida. Discovered through phylogenetic analyses, it is the largest clade of annelids, comprised by the last common ancestor of the highly diverse sister groups Errantia and Sedentaria (Clitellata and related polychaetes) and all the descendants of that ancestor. Phylogeny Pleistoannelida is composed by two big clades: Errantia (Eunicida, eunicids, siboglinids and related polychaetes) and Sedentaria (spoon worms, Siboglinidae, tubeworms, clitellates and related polychaetes). There are also smaller groups of difficult placement, such as Myzostomida and Spintheridae, that belong to either one of them. Closely related to Pleistoannelida is a grade of basal annelids: the Amphinomida/Sipunculida/''Lobatocerebrum'' clade, Chaetopterida and Palaeoannelida. A possible, closer sister group to Pleistoannelida could be Dinophiliformia, a clade containing interstitial (meiofaunal) genera p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Errantia
Errantia is a diverse group of marine polychaete worms in the phylum Annelida. Traditionally a subclass of the paraphyletic class "Polychaeta", it is currently regarded as a monophyletic group within the larger Pleistoannelida, composed of Errantia and Sedentaria. These worms are found worldwide in marine environments and brackish water. Phylogeny The phylogeny of polychaetes is slowly being resolved. Errantia and Sedentaria are the two biggest clades of polychaetes, and together they compose clade Pleistoannelida. Two groups are nested within Errantia: Aciculata (Eunicida + Phyllodocida) and Protodriliformia (small meiofaunal worms such as the Protodrilida). Historically, the order Amphinomida was part of this subclass. However, phylogenetic analyses place Amphinomida inside a basal clade with Sipunculida and '' Lobatocerebrum'', and this clade is the sister group to Pleistoannelida. Some taxa, such as Spintheridae and Myzostomida, are still difficult to place due to their lon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aciculata
Errantia is a diverse group of marine polychaete worms in the phylum Annelida. Traditionally a subclass of the paraphyletic class "Polychaeta", it is currently regarded as a monophyletic group within the larger Pleistoannelida, composed of Errantia and Sedentaria. These worms are found worldwide in marine environments and brackish water. Phylogeny The phylogeny of polychaetes is slowly being resolved. Errantia and Sedentaria are the two biggest clades of polychaetes, and together they compose clade Pleistoannelida. Two groups are nested within Errantia: Aciculata (Eunicida + Phyllodocida) and Protodriliformia ( small meiofaunal worms such as the Protodrilida). Historically, the order Amphinomida was part of this subclass. However, phylogenetic analyses place Amphinomida inside a basal clade with Sipunculida and '' Lobatocerebrum'', and this clade is the sister group to Pleistoannelida. Some taxa, such as Spintheridae and Myzostomida, are still difficult to place due to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annelid
The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with 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-groups of polycha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Annelid Worm
The annelids (Annelida , from Latin ', "little ring"), also known as the segmented worms, are a large phylum, with 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-groups of polychaetes. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sedentaria
Sedentaria is a diverse clade of annelid worms. It is traditionally treated as a subclass of the paraphyletic class Polychaeta, but it is also a monophyletic group uniting several polychaetes and the monophyletic class Clitellata. It is the sister group of Errantia. Phylogeny The phylogeny of polychaetes is slowly being resolved. Sedentaria and Errantia are the two biggest clades of polychaetes, and together they compose clade Pleistoannelida. Sedentaria's most basal clade is Orbiniida. Other groups that are nested within Sedentaria are: Clitellata, the Sabellida/Spionida clade, Opheliida, Echiura, Cirratuliformia, Terebelliformia, Maldanomorpha and the families Siboglinidae and Capitellidae. Some taxa, such as Spintheridae and Myzostomida, are still difficult to place due to their long branching, but they likely belong to either Errantia Errantia is a diverse group of marine polychaete worms in the phylum Annelida. Traditionally a subclass of the paraphyletic class "Polycha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protodriliformia
Protodriliformia is a clade of small marine life, marine polychaetes, comprised by the groups of meiofaunal interstitial worms Protodrilida and Polygordiidae, formerly considered "archiannelida, archiannelids". It is the most basal clade of Errantia. Evolutionary history Phylogenetic analysis of annelids has found Protodriliformia to be the earliest diverging clade of Errantia. At the same time, the other half of "archiannelid" worms, Orbiniida, was found to be the earliest diverging clade of Sedentaria. The Convergent evolution, convergence between these two groups occurred through progenesis and miniaturization, as a way to adapt to the marine interstitial ecosystem between sand grains (i.e. interstitium). This means that the larval or juvenile stages of a larger pleistoannelida, pleistoannelid ancestor temporarily inhabiting the interstitium stopped their somatic cell, somatic growth, became Sexual maturity, sexually mature and stayed in the interstitium permanently. Reference ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbiniida
Orbiniida is an order of small polychaete worms in the phylum Annelida. It is the earliest diverging clade in Sedentaria. Along with Protodriliformia (in Errantia), this order is composed of meiofaunal marine life, marine worms formerly known as "Archiannelida, archiannelids". These worms inhabit the Marine life, marine interstitial ecosystem, the space between sand grains. Classification First mentioned in 1977, Orbiniida was an order of the polyphyletic infraclass "Scolecida" of the class "Polychaeta". It was composed of the families Orbiniidae, Paraonidae and Questidae, all of which share in common the lack of antennae and palps, and the presence of an eversible pharynx and biramous parapodia with simple chaetae. However, through phylogenetic analysis it was found that Questidae and Paraonidae are more closely related to Clitellata and Cirratulida respectively. Because of this, the taxonomic composition of Orbiniida was changed to exclude these two families and include several i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sabellida
Sabellida is an order of annelid worms in the class Polychaeta. They are filter feeders with no buccal organ. The prostomium is fused with the peristomium and bears a ring of feathery feeding tentacles. They live in parchment-like tubes made of particles from their environment such as sand and shell fragments cemented together with mucus. Members of the suborder include the s (Sabellidae) and serpulid worms (Serpulidae). Among the species are the giant feather duster worm ('' |
Myzostomida
The Myzostomida or Myzostomatida are an order of small marine worms, which are parasitic on echinoderms, mostly crinoids. These highly unusual and diverse annelids were first discovered by Friedrich Sigismund Leuckart in 1827. Morphology A typical myzostomid has a flattened, rounded shape, with a thin edge drawn out into delicate radiating hairs called cirri. The dorsal surface is smooth, with five pairs of parapodia on the bottom surface. These parapodia are armed with supporting and hooked setae, by means of which the worm adheres to its host. Beyond the parapodia are four pairs of organs, often called suckers. These organs are probably of sensory nature, and are comparable to the lateral sense organs of capitellids. The mouth and cloacal opening are generally at opposite ends of the bottom surface. The former leads to a protrusible pharynx, from which the esophagus opens into a wide intestinal chamber with branching lateral diverticula. There appears to be no vascular syst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinther
Spintheridae is a family of marine polychaete worms with a single genus, ''Spinther'', containing these species: * ''Spinther alaskensis'' Hartman, 1948 * ''Spinther arcticus'' (M. Sars, 1851) (includes Spinther miniaceus'' Grube, 1860) *''Spinther australiensis'' Augener, 1913 * ''Spinther citrinus'' (Stimpson, 1854) *'' Spinther ericinus'' Yamamoto & Imajima, 1985 *''Spinther hystrix'' Uschakov, 1950 * ''Spinther japonicus'' Imajima and Hartman, 1964 * ''Spinther oniscoides'' Johnston, 1845 *''Spinther sagamiensis'' Imajima, 2003 *''Spinther usarpia'' Hartman, 1967 * ''Spinther vegae'' Augener, 1928 (includes ''Spinther wireni Spintheridae is a family of marine polychaete worms with a single genus, ''Spinther'', containing these species: * '' Spinther alaskensis'' Hartman, 1948 * '' Spinther arcticus'' (M. Sars, 1851) (includes Spinther miniaceus'' Grube, 1860) *''Sp ...'' Hartman, 1948) The animal lives as a symbiont on sponges. Johnston's paper does not explain the choi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aberranta
''Aberranta'' is a genus of polychaete thought to be related to the Nerillidae The Nerillidae are a family of invertebrates containing these genera: * '' Meganerilla'' * '' Mesonerilla'' * '' Nerilla'' * '' Nerillidium'' * '' Nerillidopsis'' * '' Paranerilla'' * '' Psammoriedlia'' * '' Thalassochaetus'' * '' Troglochaetus'' ....Mackie, A. S. Y., Pleijel, F., & Rouse, G. W. (2005). Revision of ~Aberranta~ Hartman, 1965 (Aberrantidae: Annelida), with descriptions of new species from the Mediterranean and Hong Kong. Marine Ecology, 26(3–4), 197–208. http://doi.org/10.1111/j.1439-0485.2005.00064.x References {{Taxonbar, from=Q3899337 Protostome enigmatic taxa Polychaete genera ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
