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Paraspadella Sheardi
''Paraspadella'' is a genus of Chaetognatha, chaetognaths in the Family (biology), family Spadellidae. ''Paraspadella'' was originally considered as ''Spadella'' before a revision separated that genus into three genera: ''Spadella'', ''Paraspadella'', and ''Gephyrospadella'', the last of which is now synonymised to ''Paraspadella''. The initial division was based on previous knowledge of three groups of ''Spadella'', in a similar manner in which ''Sagitta'' was divided into a family of genera. ''Paraspadella'' is differentiated from ''Spadella'' by the presence of disparate (digital) adhesive organs, present in the former to various degrees, but entirely absent in the latter. Species *''Paraspadella anops'' Bowman & Bieri, 1989Bowman, T. & Bieri, R. (1989). ''Paraspadella anops'', new species, from Sagittarius Cave, Grand Bahama Island, the second troglobitic chaetognath. ''Proceedings of the Biological Society of Washington'', 102(3), 586–589. *''Paraspadella caecafea'' (von Sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In binomial nomenclature, the genus name forms the first part of the binomial species name for each species within the genus. :E.g. ''Panthera leo'' (lion) and ''Panthera onca'' (jaguar) are two species within the genus ''Panthera''. ''Panthera'' is a genus within the family Felidae. The composition of a genus is determined by taxonomy (biology), taxonomists. The standards for genus classification are not strictly codified, so different authorities often produce different classifications for genera. There are some general practices used, however, including the idea that a newly defined genus should fulfill these three criteria to be descriptively useful: # monophyly – all descendants of an ancestral taxon are grouped together (i.e. Phylogeneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaetognatha
The Chaetognatha or chaetognaths (meaning ''bristle-jaws'') are a phylum of predatory marine worms that are a major component of plankton worldwide. Commonly known as arrow worms, they are mostly pelagic; however about 20% of the known species are benthic, and can attach to algae and rocks. They are found in all marine waters, from surface tropical waters and shallow tide pools to the deep sea and polar regions. Most chaetognaths are transparent and are torpedo shaped, but some deep-sea species are orange. They range in size from . Chaetognaths were first recorded by the Dutch naturalist Martinus Slabber in 1775. As of 2021, biologists recognize 133 modern species assigned to over 26 genera and eight families. Despite the limited diversity of species, the number of individuals is large. Arrow worms are strictly related to and possibly belonging to Gnathifera, a clade of protostomes that do not belong to either Ecdysozoa or Lophotrochozoa. Anatomy Chaetognaths are transpar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Family (biology)
Family (, : ) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between order and genus. A family may be divided into subfamilies, which are intermediate ranks between the ranks of family and genus. The official family names are Latin in origin; however, popular names are often used: for example, walnut trees and hickory trees belong to the family Juglandaceae, but that family is commonly referred to as the "walnut family". The delineation of what constitutes a family—or whether a described family should be acknowledged—is established and decided upon by active taxonomists. There are not strict regulations for outlining or acknowledging a family, yet in the realm of plants, these classifications often rely on both the vegetative and reproductive characteristics of plant species. Taxonomists frequently hold varying perspectives on these descriptions, leading to a lack of widespread consensus within the scientific community ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spadellidae
Spadellidae is a family of sagittoideans in the order Phragmophora. Spadellidae prey on plankton and commonly reside in the epipelagic zone of the ocean. Genera *'' Bathyspadella'' Tokioka, 1939Tokioka, T. (1939). Three new chaetognaths from Japanese waters. ''Memoirs of the Imperial Marine Observatory'', 7, 129–139. *'' Calispadella'' Casanova & Moreau, 2005Casanova, J. Moreau, X. (2005). ''Calispadella alata'' n. gen., n. sp., the first chaetognath recorded from a hydrothermal vent Hydrothermal vents are fissures on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hot ... site (Mid-Atlantic Ridge). ''Journal of Plankton Research'', 27(2), 221–225. *'' Hemispadella'' Casanova, 1996Casanova, J. (1996). A new genus and species of deep benthic chaetognath from the Atlantic: a probable link between the families Heterok ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spadella
Lead ''Spadella'' is a genus of small, transparent marine invertebrates belonging to the family Spadellidae within the phylum Chaetognatha, commonly known as arrow worms. Unlike most chaetognaths, which are pelagic (free-swimming in open water), species of ''Spadella'' are benthic, meaning they live near the seafloor and often attach to substrates in shallow marine environments. The first recorded observation of a ''Spadella'' species was made by Busch in 1851, when ''Spadella cephaloptera'' was first reported. However, the genus itself was formally described by Langerhans in 1880, and currently includes several recognized species. ''Spadella'' species play an important role in marine food webs, preying on copepods and other planktonic organisms. They have also been of scientific interest due to their unique evolutionary traits, particularly in the context of bilaterian phylogeny and ''Hox'' gene organization, which has led to debates on the evolutionary origins of chaetognat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sagitta
Sagitta is a dim but distinctive constellation in the northern sky. Its name is Latin for 'arrow', not to be confused with the significantly larger constellation Sagittarius 'the archer'. It was included among the 48 constellations listed by the 2nd-century astronomer Ptolemy, and it remains one of the 88 modern constellations defined by the International Astronomical Union. Although it dates to antiquity, Sagitta has no star brighter than 3rd magnitude and has the third-smallest area of any constellation. Gamma Sagittae is the constellation's brightest star, with an apparent magnitude of 3.47. It is an aging red giant star 90% as massive as the Sun that has cooled and expanded to a radius 54 times greater than it. Delta, Epsilon, Zeta, and Theta Sagittae are each multiple stars whose components can be seen in small telescopes. V Sagittae is a cataclysmic variable—a binary star system composed of a white dwarf accreting mass of a donor star that is expected to go ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paraspadella Anops
''Paraspadella'' is a genus of chaetognaths in the family Spadellidae. ''Paraspadella'' was originally considered as ''Spadella'' before a revision separated that genus into three genera: ''Spadella'', ''Paraspadella'', and ''Gephyrospadella'', the last of which is now synonymised to ''Paraspadella''. The initial division was based on previous knowledge of three groups of ''Spadella'', in a similar manner in which ''Sagitta'' was divided into a family of genera. ''Paraspadella'' is differentiated from ''Spadella'' by the presence of disparate (digital) adhesive organs, present in the former to various degrees, but entirely absent in the latter. Species *'' Paraspadella anops'' Bowman & Bieri, 1989Bowman, T. & Bieri, R. (1989). ''Paraspadella anops'', new species, from Sagittarius Cave, Grand Bahama Island, the second troglobitic chaetognath. ''Proceedings of the Biological Society of Washington'', 102(3), 586–589. *'' Paraspadella caecafea'' (von Salvini-Plawen, 1986) *'' Parasp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
