|
Weinbergina Opitzi
''Weinbergina'' is a genus of synziphosurine, a paraphyletic group of fossil chelicerate arthropods. Fossils of the single and type species, ''W. opitzi'', have been discovered in deposits of the Devonian period in the Hunsrück Slate, Germany. Morphology ''Weinbergina'' is a relatively large synziphosurine, ranging about 7 cm to 10 cm in full body length. The prosoma is covered by a semicircular carapace with blunt genal cornua (posterolateral corners). There is possible evidence of lateral eyes located just below the ophthalmic ridges. The opisthosoma is externally 10-segmented, expressed by tergites that possess blunt tergopleurae (lateral extension) and axial nodes. However, the opisthosoma is most likely 11-segmented in origin, with the first segment being highly reduced (a synapomorphy of euchelicerates) and possibly covered by the preceding carapace. The last 3 segments form a narrow postabdomen and lacking lateral nodes. Compared to other synziphosurines with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Naturmuseum Senckenberg
The Naturmuseum Senckenberg is a museum of natural history, located in Frankfurt am Main. It is the second-largest of its type in Germany. The museum contains a large and diverse collection of birds with 90,000 bird skins, 5,050 egg sets, 17,000 skeletons, and 3,375 spirit specimens (a specimen preserved in fluid). In 2010, almost 517,000 people visited the museum. The building housing the Senckenberg Museum was erected between 1904 and 1907 outside of the center of Frankfurt in the same area as the Johann Wolfgang Goethe University, which was founded in 1914. The museum is owned and operated by the Senckenberg Nature Research Society, which began with an endowment by Johann Christian Senckenberg. Attractions include a ''Diplodocus'' (donated by the American Museum of Natural History on the occasion of the present museum building's inauguration in 1907), the crested Hadrosaur ''Parasaurolophus'', a fossilized ''Psittacosaurus'' with clear bristles around its tail and visible f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synapomorphy
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have evolved in their most recent common ancestor. ) In cladistics, synapomorphy implies homology. Examples of apomorphy are the presence of erect gait, fur, the evolution of three middle ear bones, and mammary glands in mammals but not in other vertebrate animals such as amphibians or reptiles, which have retained their ancestral traits of a sprawling gait and lack of fur. Thus, these derived traits are also synapomorphies of mammals in general as they are not shared by other vertebrate animals. Etymology The word —coined by German entomologist Willi Hennig—is derived from the Ancient Greek words (''sún''), meaning "with, together"; (''apó''), meaning "away from"; and (''morphḗ''), meaning "shape, form". Clade analysis T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Benthic
The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from ancient Greek, βένθος (bénthos), meaning "the depths." Organisms living in this zone are called benthos and include microorganisms (e.g., bacteria and fungi) as well as larger invertebrates, such as crustaceans and polychaetes. Organisms here generally live in close relationship with the substrate and many are permanently attached to the bottom. The benthic boundary layer, which includes the bottom layer of water and the uppermost layer of sediment directly influenced by the overlying water, is an integral part of the benthic zone, as it greatly influences the biological activity that takes place there. Examples of contact soil layers include sand bottoms, rocky outcrops, coral, and bay mud. Description Oceans The benthic region of the ocean begins at the shore line (intertidal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dibasterium
''Dibasterium'' is an extinct genus of euchelicerate, a group of chelicerate arthropods. Fossils of the single and type species, ''D. durgae'', have been discovered in the Coalbrookdale Formation of the Middle Silurian period (Homerian age) in Herefordshire, England (in the United Kingdom). The name of the genus is derived from the Latin words ''dibamos'' ("on two legs") and '' mysterium'' ("mystery"), meaning "mystery on two legs" and referring to its prosomal (of the head) limbs. The species name ''durgae'' comes from Durga, a Hindu goddess Devī (; Sanskrit: देवी) is the Sanskrit word for 'goddess'; the masculine form is ''deva''. ''Devi'' and ''deva'' mean 'heavenly, divine, anything of excellence', and are also gender-specific terms for a deity in Hinduism. The conce ... with many arms. References Euchelicerata Fossils of England Silurian arthropods of Europe Silurian animals Wenlock first appearances Homerian extinctions Fossil taxa described in 2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Offacolus
''Offacolus'' is an extinct genus of euchelicerate, a group of chelicerate arthropods. Its only species, ''O. kingi'', has been found in deposits from the Silurian period (Homerian epoch) in the Wenlock Series Lagerstätte of Herefordshire, England. It is the only member of the monotypic family Offacolidae, and classified as a basal ("primitive") genus in the clade Euchelicerata, along with ''Dibasterium'' and Prosomapoda. The genus is named after Offa, a king from the ancient kingdom of Mercia, and ''colus'', a person who dwelled among (this time referring to) the Offa's Dyke. The species name honors Robert Joseph King, a British mineralogist who found the fossils of ''Offacolus''. Similar to ''Dibasterium'', ''Offacolus'' possess limb-like exopods (outer limb branches) on appendage II to V, a character suggest to be plesiomorphic (observable in the putative stem-chelicerate taxon Habeliida) and lost within the prosomapod clade. Classification ''Offacolus'' was originally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Spider
Sea spiders are marine arthropods of the order Pantopoda ( ‘all feet’), belonging to the class Pycnogonida, hence they are also called pycnogonids (; named after ''Pycnogonum'', the type genus; with the suffix '). They are cosmopolitan, found in oceans around the world. The over 1,300 known species have legs ranging from to over . Most are toward the smaller end of this range in relatively shallow depths; however, they can grow to be quite large in Antarctic and deep waters. Although "sea spiders" are not true spiders, or even arachnids, their traditional classification as chelicerates places them closer to true spiders than to other well-known arthropod groups, such as insects or crustaceans. This is in dispute, however, as genetic evidence suggests they may be the sister group to all other living arthropods. Description Sea spiders have long legs in contrast to a small body size. The number of walking legs is usually eight (four pairs), but the family Pycnogonidae hav ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dekatriata
Dekatriata is a clade of planatergan chelicerates including the groups Arachnida, Chasmataspidida, Eurypterid Eurypterids, often informally called sea scorpions, are a group of extinct arthropods that form the order Eurypterida. The earliest known eurypterids date to the Darriwilian stage of the Ordovician period 467.3 million years ago. The group is l ...a and additionally two stem-genera '' Winneshiekia'' and '' Houia''. Dekatriata is defined by an opisthosoma with 13 segments as groundplan (the number proposed to be secondarily reduced in most arachnid orders) and fused, plate-like appendages on the first opisthosomal segment (somite VII). References Middle Ordovician first appearances {{Chelicerata-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] |
Horseshoe Crab
Horseshoe crabs are marine and brackish water arthropods of the family Limulidae and the only living members of the order Xiphosura. Despite their name, they are not true crabs or crustaceans: they are chelicerates, most closely related to arachnids, such as spiders and scorpions. Horseshoe crabs live primarily in and around shallow coastal waters on soft, sandy or muddy bottoms. They are generally found in the intertidal zone at spring high tides. They are eaten in some parts of Asia, and used as fishing bait, in fertilizer and in science (especially ''Limulus'' amebocyte lysate). In recent years, population declines have occurred as a consequence of coastal habitat destruction and overharvesting. Tetrodotoxin may be present in one horseshoe crab species, '' Carcinoscorpius rotundicauda''. Fossil records for horseshoe crabs extend back as far as 480 million years ago, with extant forms being living fossils. A 2019 molecular analysis places them as the sister group of Ricinule ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chilaria
Xiphosura () is an order of arthropods related to arachnids. They are more commonly known as horseshoe crabs (a name applied more specifically to the only extant family, Limulidae). They first appeared in the Hirnantian (Late Ordovician). Currently, there are only four living species. Xiphosura contains one suborder, Xiphosurida, and several stem-genera. The group has hardly changed in appearance in hundreds of millions of years; the modern horseshoe crabs look almost identical to prehistoric genera and are considered to be living fossils. The most notable difference between ancient and modern forms is that the abdominal segments in present species are fused into a single unit in adults. Xiphosura were historically placed in the class Merostomata, although this term was intended to encompass also the eurypterids, whence it denoted what is now known to be an unnatural (paraphyletic) group (although this is a grouping recovered in some recent cladistic analyses). Although the name ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homology (biology)
In biology, homology is similarity due to shared ancestry between a pair of structures or genes in different taxa. A common example of homologous structures is the forelimbs of vertebrates, where the wings of bats and birds, the arms of primates, the front flippers of whales and the forelegs of four-legged vertebrates like dogs and crocodiles are all derived from the same ancestral tetrapod structure. Evolutionary biology explains homologous structures adapted to different purposes as the result of descent with modification from a common ancestor. The term was first applied to biology in a non-evolutionary context by the anatomist Richard Owen in 1843. Homology was later explained by Charles Darwin's theory of evolution in 1859, but had been observed before this, from Aristotle onwards, and it was explicitly analysed by Pierre Belon in 1555. In developmental biology, organs that developed in the embryo in the same manner and from similar origins, such as from matching p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Book Gill
A book is a medium for recording information in the form of writing or images, typically composed of many pages (made of papyrus, parchment, vellum, or paper) bound together and protected by a cover. The technical term for this physical arrangement is ''codex'' (plural, ''codices''). In the history of hand-held physical supports for extended written compositions or records, the codex replaces its predecessor, the scroll. A single sheet in a codex is a leaf and each side of a leaf is a page. As an intellectual object, a book is prototypically a composition of such great length that it takes a considerable investment of time to compose and still considered as an investment of time to read. In a restricted sense, a book is a self-sufficient section or part of a longer composition, a usage reflecting that, in antiquity, long works had to be written on several scrolls and each scroll had to be identified by the book it contained. Each part of Aristotle's ''Physics'' is called a bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
