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Xanthomyria
''Xanthomyria'' is a genus of Cambrian arthropod from the Ust-Mayan Formation of Siberia. It contains one species, ''Xanthomyria spinosa ''. Description ''Xanthomyria'' is known from two specimens, exhibiting great variation in size. Neither specimen preserves the head or legs, therefore its affinity is uncertain. However, various structures of the exoskeleton such as wikt:tuberculate, tuberculate and spinose tergites with a broad wikt:rachis, rachis and narrow wikt:pleurae, pleurae rule out most Cambrian clades of arthropod, and unusually in this regard ''Xanthomyria'' is most similar to Carboniferous archipolypodans such as ''Euphoberia''. If this affinity is accurate, it would give millipedes an almost 100 million-year long ghost lineage from the late Cambrian to the late Silurian. However, it is more likely that ''Xanthomyria'' instead belongs to a wholly extinct myriapod-like clade of arthropods along with forms like ''Pseudoiulia'', due to true stem-group myriapods which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Archipolypoda
Archipolypoda is an extinct group of millipedes known from fossils in Europe and North America and containing the earliest known land animals. The Archipolypoda was erected by Scudder (1882) but redefined in 2005 with the description of several new species from Scotland. Distinguishing characteristics include relatively large eyes with densely packed ocelli (sometimes interpreted as compound eyes), and modified leg pairs on the 8th body ring. Some species had prominent spines while others had a flattened appearance. Classification The Archipolypoda as currently recognized consists of four orders, many with monotypic families and genera, as well as five species of uncertain placement (''incertae sedis''). Archidesmida Wilson & Anderson, 2004 * Archidesmidae Scudder, 1885 **'' Archidesmus macnicoli'' Peach, 1882. Lower Devonian, Scotland * Zanclodesmidae Wilson, Daeschler & Desbiens, 2005 **'' Zanclodesmus willetti'' Wilson, Daeschler & Desbiens, 2005. Upper Devonian, Q ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthropod
Arthropods ( ) are invertebrates in the phylum Arthropoda. They possess an arthropod exoskeleton, exoskeleton with a cuticle made of chitin, often Mineralization (biology), mineralised with calcium carbonate, a body with differentiated (Metamerism (biology), metameric) Segmentation (biology), segments, and paired jointed appendages. In order to keep growing, they must go through stages of moulting, a process by which they shed their exoskeleton to reveal a new one. They form an extremely diverse group of up to ten million species. Haemolymph is the analogue of blood for most arthropods. An arthropod has an open circulatory system, with a body cavity called a haemocoel through which haemolymph circulates to the interior Organ (anatomy), organs. Like their exteriors, the internal organs of arthropods are generally built of repeated segments. They have ladder-like nervous systems, with paired Anatomical terms of location#Dorsal and ventral, ventral Ventral nerve cord, nerve cord ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pseudoiulia
''Pseudoiulia'' is a genus of Cambrian arthropod known from the Chengjiang Biota of Yunnan, China, containing the single species ''P. cambriensis''. It is considered poorly known, but has been somewhat associated with other Chengjiang Biota fauna such as ''Dongshania folliformis'' and '' Pisinnocaris subconigera''. In 2013, ''Pseudoiulia'' was suggested to be a member of the family Kootenichelidae, alongside ''Kootenichela'' and '' Worthenella.'' See also * Arthropod * Cambrian explosion * Chengjiang biota ** List of Chengjiang Biota species by phylum This is a list of fossils found at Maotianshan Shales, whose most famous assemblage of organisms are referred to as the Chengjiang biota. The Maotianshan Shales are a series of Cambrian, Early Cambrian Shale, sedimentary deposits in the Chiungch ... References Cambrian animals Maotianshan shales fossils Prehistoric arthropod genera {{paleo-arthropod-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleozoic Russia
The Paleozoic ( , , ; or Palaeozoic) Era is the first of three geological eras of the Phanerozoic Eon. Beginning 538.8 million years ago (Ma), it succeeds the Neoproterozoic (the last era of the Proterozoic Eon) and ends 251.9 Ma at the start of the Mesozoic Era. The Paleozoic is subdivided into six geologic periods (from oldest to youngest), Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian. Some geological timescales divide the Paleozoic informally into early and late sub-eras: the Early Paleozoic consisting of the Cambrian, Ordovician and Silurian; the Late Paleozoic consisting of the Devonian, Carboniferous and Permian. The name ''Paleozoic'' was first used by Adam Sedgwick (1785–1873) in 1838 to describe the Cambrian and Ordovician periods. It was redefined by John Phillips (1800–1874) in 1840 to cover the Cambrian to Permian periods. It is derived from the Greek ''palaiós'' (παλαιός, "old") and ''zōḗ'' (ζωή, "life") meaning "ancient life ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cambrian Arthropods
The Cambrian ( ) is the first geological period of the Paleozoic Era, and the Phanerozoic Eon. The Cambrian lasted 51.95 million years from the end of the preceding Ediacaran period 538.8 Ma (million years ago) to the beginning of the Ordovician Period 486.85 Ma. Most of the continents lay in the southern hemisphere surrounded by the vast Panthalassa, Panthalassa Ocean. The assembly of Gondwana during the Ediacaran and early Cambrian led to the development of new Convergent boundary, convergent plate boundaries and Volcanic arc, continental-margin arc magmatism along its margins that helped drive up global temperatures. Laurentia lay across the equator, separated from Gondwana by the opening Iapetus Ocean. The Cambrian marked a profound change in Life, life on Earth; prior to the Period, the majority of living organisms were small, Unicellular organism, unicellular and poorly preserved. Complex, multicellular organisms gradually became more common during the Ediacaran, but it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enigmatic Arthropod Taxa
Enigmatic is an adjective meaning "mysterious" or "puzzling". It may also refer to: * ''Enigmatic'' (album), a 1970 album by Czesław Niemen * '' Enigmatic: Calling'', a 2005 album by Norwegian progressive metal band Pagan's Mind * Enigmatic scale, musical scale used by Verdi and others * "The Enigmatic", a song by Joe Satriani on the album '' Not of This Earth'' See also * Enigmatic leaf turtle, a species of Asian leaf turtle * Enigmatic moray eel, a species found in the Pacific and Indian Oceans * ''Glaresis ''Glaresis'' is a genus of beetles, sometimes called "Enigmatic scarab beetles", in its own family, Glaresidae. It is closely related to, and was formerly included in, the family Scarabaeidae. Although its members occur in arid and sandy areas wo ...'', a genus of beetles sometimes called "enigmatic scarab beetles" * Enigma (other) {{disambig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tergites
A ''tergum'' (Latin for "the back"; : ''terga'', associated adjective tergal) is the dorsal ('upper') portion of an arthropod segment other than the head. The anterior edge is called the 'base' and posterior edge is called the 'apex' or 'margin'. A given tergum may be divided into hardened plates or sclerites commonly referred to as tergites. In a thoracic segment, for example, the tergum may be divided into an anterior notum and a posterior scutellum. Lateral extensions of a tergite are known as paranota (Greek for "alongside the back") or ''carinae'' (Latin for "keel"), exemplified by the flat-backed millipedes of the order Polydesmida. Kinorhynchs have tergal and sternal plates too, though seemingly not homologous with those of arthropods. Tergo-tergal is a stridulatory mechanism in which fine spines of the abdominal tergites are rubbed together to produce sound. This process is known as abdominal telescoping. Examples File:Andrena spiraeana abdomen.jpg , Abdominal tergum ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euthycarcinoidea
Euthycarcinoidea are an enigmatic group of extinct, possibly amphibious arthropods that ranged from Cambrian to Triassic times. Fossils are known from Europe, North America, Argentina, Australia, and Antarctica. Description The euthycarcinoid body was divided into a cephalon (head), preabdomen, and postabdomen. The cephalon consisted of two segments and included mandibles, antennae and presumed eyes. The preabdomen consisted of five to fourteen tergites, each having up to three somites. Each somite had in turn a pair of uniramous, segmented legs. The postabdomen was limbless and consisted of up to six segments and a terminal tail spine. Affinities Due to its particular combination of characteristics, the position of the Euthycarcinoidea within the Arthropoda has been ambiguous; previous authors have allied euthycarcinoids with crustaceans (interpreted as copepods, branchiopods, or an independent group), with trilobites, or the merostomatans (horseshoe crabs and sea scorpion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ghost Lineage
A ghost lineage is a hypothesized ancestor in a species lineage that has left no fossil evidence, but can still be inferred to exist or have existed because of gaps in the fossil record or genomic evidence. The process of determining a ghost lineage relies on fossilized evidence before and after the hypothetical existence of the lineage and extrapolating relationships between organisms based on phylogenetic analysis. Ghost lineages assume unseen diversity in the fossil record and serve as predictions for what the fossil record could eventually yield; these hypotheses can be tested by unearthing new fossils or running phylogenetic analyses. Ghost lineages and Lazarus taxa are related concepts, as both stem from gaps in the fossil record. A ghost lineage is any gap in a taxon's fossil record, with or without reappearance, while a Lazarus taxon is a type of ghost lineage wherein a species is believed to have gone extinct due to an absence of it in the fossil record, but then reappea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silurian
The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of the Paleozoic Era, and the third of twelve periods of the Phanerozoic Eon. As with other geologic periods, the rock beds that define the period's start and end are well identified, but the exact dates are uncertain by a few million years. The base of the Silurian is set at a series of major Ordovician–Silurian extinction events when up to 60% of marine genera were wiped out. One important event in this period was the initial establishment of terrestrial life in what is known as the Silurian-Devonian Terrestrial Revolution: vascular plants emerged from more primitive land plants, dikaryan fungi started expanding and diversifying along with glomeromycotan fungi, and three groups of arthropods ( myriapods, arachnids and hexapods) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Euphoberia
''Euphoberia'' is an extinct genus of millipede from the Pennsylvanian epoch of the Late Carboniferous, measuring up to in length, that is small in Euphoberiidae which contains species with length about . Fossils have been found in Europe and North America. There has been uncertainty about the appropriate classification of ''Euphoberia'' since its description in 1868: it has been referred to as a centipede, millipede, or a separate, independent group within the myriapods. It is currently placed in the Archipolypoda Archipolypoda is an extinct group of millipedes known from fossils in Europe and North America and containing the earliest known land animals. The Archipolypoda was erected by Scudder (1882) but redefined in 2005 with the description of sever ..., an extinct group of millipedes. Several species described in the late 19th century have since been assigned to the related genera '' Myriacantherpestes'' and '' Acantherpestes''. References Carboniferous myri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
