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Bassipterus
''Bassipterus'' ("wing from Bass") is a genus of eurypterid, an extinct group of aquatic arthropods. ''Bassipterus'' is classified as part of the family Adelophthalmidae, the only clade within the derived ("advanced") Adelophthalmoidea superfamily of eurypterids. Fossils of the single and type species, ''B. virgnicus'', have been discovered in deposits of the Late Silurian age in West Virginia and Maryland, United States. The genus is named after Bass, where most of the fossils have been recovered. ''Bassipterus'' was a well-known basal ("primitive") genus that was distinguished from the more derived adelophthalmids by the specialization of its genital operculum (a plate-like segment which contains the genital aperture) and its long and narrow eyes, being '' Pittsfordipterus''s closest relative. Description ''Bassipterus'' is almost completely known, with the first to fifth pair of limbs and type B genital appendage being the only unknown body parts. The body had a lanceola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bassipterus Virginicus Metastoma
''Bassipterus'' ("wing from Bass") is a genus of eurypterid, an extinct group of aquatic arthropods. ''Bassipterus'' is classified as part of the family Adelophthalmidae, the only clade within the derived ("advanced") Adelophthalmoidea superfamily of eurypterids. Fossils of the single and type species, ''B. virgnicus'', have been discovered in deposits of the Late Silurian age in West Virginia and Maryland, United States. The genus is named after Bass, where most of the fossils have been recovered. ''Bassipterus'' was a well-known basal ("primitive") genus that was distinguished from the more derived adelophthalmids by the specialization of its genital operculum (a plate-like segment which contains the genital aperture) and its long and narrow eyes, being ''Pittsfordipterus''s closest relative. Description ''Bassipterus'' is almost completely known, with the first to fifth pair of limbs and type B genital appendage being the only unknown body parts. The body had a la ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adelophthalmoidea
Adelophthalmidae (the name deriving from the type genus ''Adelophthalmus'', meaning "no obvious eyes") is a family of eurypterids, an extinct group of aquatic arthropods. Adelophthalmidae is the only family classified as part of the superfamily Adelophthalmoidea, which in turn is classified within the infraorder Diploperculata in the suborder Eurypterina. Adelophthalmid eurypterids were small and swimming eurypterids that appeared in the Silurian period. With the earliest known members of the group, '' Nanahughmilleria prominens'' and '' Parahughmilleria maria'', being known from deposits of Early Silurian (possibly the Llandovery epoch) age and the last members, belonging to the long-lasting and widespread genus ''Adelophthalmus'', going extinct in the Cisuralian, Early Permian, the Adelophthalmidae is the longest lasting single family of eurypterids. The survival of the group, and of swimming eurypterids (the suborder Eurypterina) beyond the Late Devonian is entirely due to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adelophthalmidae
Adelophthalmidae (the name deriving from the type genus ''Adelophthalmus'', meaning "no obvious eyes") is a family of eurypterids, an extinct group of aquatic arthropods. Adelophthalmidae is the only family classified as part of the superfamily Adelophthalmoidea, which in turn is classified within the infraorder Diploperculata in the suborder Eurypterina. Adelophthalmid eurypterids were small and swimming eurypterids that appeared in the Silurian period. With the earliest known members of the group, '' Nanahughmilleria prominens'' and '' Parahughmilleria maria'', being known from deposits of Early Silurian (possibly the Llandovery epoch) age and the last members, belonging to the long-lasting and widespread genus ''Adelophthalmus'', going extinct in the Early Permian, the Adelophthalmidae is the longest lasting single family of eurypterids. The survival of the group, and of swimming eurypterids (the suborder Eurypterina) beyond the Late Devonian is entirely due to the survival, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pittsfordipterus
''Pittsfordipterus'' ("wing from Pittsford") is a genus of eurypterid, an extinct group of aquatic arthropods. ''Pittsfordipterus'' is classified as part of the family Adelophthalmidae, the only clade in the derived ("advanced") Adelophthalmoidea superfamily of eurypterids. Fossils of the single and type species, ''P. phelpsae'', have been discovered in deposits of Silurian age in Pittsford, New York state. The genus is named after Pittsford, where the two only known specimens have been found. ''Pittsfordipterus'' was a basal ("primitive") genus that was distinguished from the more derived adelophthalmids by the specialization of its genital operculum (a plate-like segment which contains the genital aperture) and its long and narrow eyes, being ''Bassipterus'' closest relative. With an estimated length of 6 cm (2.4 in), ''Pittsfordipterus'' was one of the smallest adelophthalmids. Description Like the other adelophthalmid eurypterids, ''Pittsfordipterus'' was a small eury ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eurypterid
Eurypterids, often informally called sea scorpions, are a group of extinct arthropods that form the Order (biology), order Eurypterida. The earliest known eurypterids date to the Darriwilian stage of the Ordovician period 467.3 Myr, million years ago. The group is likely to have appeared first either during the Early Ordovician or Late Cambrian period. With approximately 250 species, the Eurypterida is the most diverse Paleozoic Chelicerata, chelicerate order. Following their appearance during the Ordovician, eurypterids became major components of marine faunas during the Silurian, from which the majority of eurypterid species have been described. The Silurian genus ''Eurypterus'' accounts for more than 90% of all known eurypterid specimens. Though the group continued to diversify during the subsequent Devonian period, the eurypterids were heavily affected by the Late Devonian extinction event. They declined in numbers and diversity until becoming extinct during the Permian–Tri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Prosoma
The cephalothorax, also called prosoma in some groups, is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. (The terms ''prosoma'' and ''opisthosoma'' are equivalent to ''cephalothorax'' and ''abdomen'' in some groups.) The word ''cephalothorax'' is derived from the Greek words for head (, ') and thorax (, '). This fusion of the head and thorax is seen in chelicerates and crustaceans; in other groups, such as the Hexapoda (including insects), the head remains free of the thorax. In horseshoe crabs and many crustaceans, a hard shell called the carapace covers the cephalothorax. Arachnid anatomy Fovea The fovea is the centre of the cephalothorax and is located behind the head (only in spiders).Dalton, Steve (2008). ''Spiders; The Ultimate Predators''. A & C Black, London. P.p. 19. . It is often important in identification. It can be transverse or procurved Smith, A. M. (1990c). Baboon spiders: Tarantulas of Afr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carapace
A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron. Crustaceans In crustaceans, the carapace functions as a protective cover over the cephalothorax (i.e., the fused head and thorax, as distinct from the abdomen behind). Where it projects forward beyond the eyes, this projection is called a rostrum (anatomy), rostrum. The carapace is Calcification, calcified to varying degrees in different crustaceans. Zooplankton within the phylum Crustacea also have a carapace. These include Cladocera, ostracods, and Isopoda, isopods, but isopods only have a developed "cephalic shield" carapace covering the head. Arachnids In arachnids, the carapace is formed by the fusion of prosomal tergites into a single Plate (animal anatomy), plate which carries the e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dorsal (anatomy)
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provides a definition of what is at the front ("anterior"), behind ("posterior") and so on. As part of defining and describing terms, the body is described through the use of anatomical planes and anatomical axes. The meaning of terms that are used can change depending on whether an organism is bipedal or quadrupedal. Additionally, for some animals such as invertebrates, some terms may not have any meaning at all; for example, an animal that is radially symmetrical will have no anterior surface, but can still have a description that a part is close to the middle ("proximal") or further from the middle ("distal"). International organisations have determined vocabularies that are often used as standard vocabularies for subdisciplines of anatom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ocelli
A simple eye (sometimes called a pigment pit) refers to a form of eye or an optical arrangement composed of a single lens and without an elaborate retina such as occurs in most vertebrates. In this sense "simple eye" is distinct from a multi-lensed "compound eye", and is not necessarily at all simple in the usual sense of the word. The structure of an animal's eye is determined by the environment in which it lives, and the behavioural tasks it must fulfill to survive. Arthropods differ widely in the habitats in which they live, as well as their visual requirements for finding food or conspecifics, and avoiding predators. Consequently, an enormous variety of eye types are found in arthropods. They possess a wide variety of novel solutions to overcome visual problems or limitations. Use of the term ''simple eye'' is flexible, and must be interpreted in proper context; for example, the eyes of humans and of other large animals such as most cephalopods, are ''camera eyes'' and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ludlow Epoch
In the geological timescale, the Ludlow Epoch (from 427.4 ± 0.5 million years ago to 423.0 ± 2.3 million years ago) occurred during the Silurian Period, after the end of the Homerian Age. It is named for the town of Ludlow in Shropshire, England. The Ludlow Epoch is subdivided into two stages: Gorstian and Ludfordian. Paleontology Arthropods See also *Ludlow Group References Ludlow epoch, Silurian geochronology, *03 Geological epochs Ludlow first appearances, {{geochronology-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metastoma
The metastoma is a ventral single plate located in the opisthosoma of non-arachnid dekatriatan chelicerates such as eurypterids, chasmataspidids and the genus ''Houia''. The metastoma located between the base of 6th prosomal appendage pair and may had functioned as part of the animal's feeding structures. It most likely represented a fused appendage pair originated from somite 7 (first opisthosomal segment), thus homologous to the chilaria of horseshoe crab and 4th walking leg pair of sea spider. In eurypterids, the plate was typically cordate (heart-shaped) in shape, though differed in shape in some genera, such as ''Megalograptus ''Megalograptus'' is a genus of eurypterid, an extinct group of aquatic arthropods. Fossils of ''Megalograptus'' have been recovered in deposits of Katian (Late Ordovician) age in North America. The genus contains five species: ''M. alveolatu ...''. References Chelicerate anatomy Dekatriata {{Chelicerata-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Compound Eyes
A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which distinguish brightness and color. The image perceived by this arthropod eye is a combination of inputs from the numerous ommatidia, which are oriented to point in slightly different directions. Compared with single-aperture eyes, compound eyes have poor image resolution; however, they possess a very large view angle and the ability to detect fast movement and, in some cases, the polarization of light. Because a compound eye is made up of a collection of ommatidia, each with its own lens, light will enter each ommatidium instead of using a single entrance point. The individual light receptors behind each lens are then turned on and off due to a series of changes in the light intensity during movement or when an object in moving, creating a flick ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
