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Cascolus
''Cascolus'' is an extinct genus of stem-mandibulate known from the Coalbrookdale Formation. Description ''Cascolus'' is a long, somewhat vermiform arthropod, roughly 9 millimetres long. It has a head segment containing a head shield, stalked eyes and five pairs of limbs, the first similar to megacheirans and the other four biramous with gnathobases, followed by a nine-segmented thorax and two possibly limbless segments near the posterior. The trunk remains similar in size through tergites 1-4, and then decreases in width onwards into the limbless segments. Ecology ''Cascolus'' appears to have been a nektobenthic animal, possibly a scavenger. Etymology ''Cascolus'' was named in honour of Sir David Attenborough. The genus name derives from "castrum" ("stronghold") and "colus" ("dwelling in"), alluding to the Middle or Old English source for the name "Attenborough". The specific name ''ravitis'' derives from "Ratae" (the Roman name for Leicester), "vita" ("life") and "com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coalbrookdale Formation
Coalbrookdale Formation, earlier known as Wenlock Shale or Wenlock Shale Formation and also referred to as Herefordshire Lagerstätte in palaeontology, is a fossil-rich deposit ('' Konservat-Lagerstätte'') in Powys and Herefordshire at the England–Wales border in UK. It belongs to the Wenlock Series of the Silurian Period within the Homerian Age (about 430 million years ago). It is known for its well-preserved fossils of various invertebrate animals many of which are in their three-dimensional structures. Some of the fossils are regarded as earliest evidences and evolutionary origin of some of the major groups of modern animals. Roderick Murchison first described the geological setting of Coalbrookdale Formation by which he gave the name Silurian in 1935, referring to the Silures, a Celtic tribe of Wales. It is assigned to the Wenlock Group in 1978 based on the age of crustacean fossils found around the region. Robert J. King of the University of Leicester discovered the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Captopodus
''Captopodus'' is an extinct genus of stem-mandibulate known from the Early Devonian. This creature was described in 2012 from four fossils found in the Hunsrück Slate, an early Devonian lagerstätten in Germany that represents one of the few marine sites from the Devonian with soft tissue preservation. Description ''Captopodus'' is a vermiform (worm-like) arthropod, with over 66 trunk segments each containing a biramous limb pair, with the final segment containing a caudal furca. The head region contains two pairs of appendages, one being antennae, and the other resembling the grasping legs of thylacocephalans. It also has cupola-like structures, the function of which is unknown. The animal measures five to ten centimetres long. It is also very similar to, and probably related to the animal ''Acheronauta'', from the Waukesha Biota The Waukesha Biota (also known as Waukesha Lagerstätte, Brandon Bridge Lagerstätte, or Brandon Bridge fauna) is an important fossil site l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thylacocephala
The Thylacocephala (from the Greek or ', meaning " pouch", and or ' meaning "head") are group of extinct probable mandibulate arthropods, that have been considered by some researchers as having possible crustacean affinities. As a class they have a short research history, having been erected in the early 1980s. They typically possess a large, laterally flattened carapace that encompasses the entire body. The compound eyes tend to be large and bulbous, and occupy a frontal notch on the carapace. They possess three pairs of large raptorial limbs, and the abdomen bears a battery of small swimming limbs. Their size ranges from ~15 mm to potentially up to 250 mm. Inconclusive claims of thylacocephalans have been reported from the lower lower Cambrian ('' Zhenghecaris''), but later study considered that genus as radiodont or arthropod with uncertain systematic position. The oldest unequivocal fossils are Upper Ordovician and Lower Silurian in age. As a group, the Thylacocephala s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acheronauta Stimulapis
''Acheronauta'' is a genus of extinct worm-shaped arthropod that lived in the early Silurian (Telychian-Sheinwoodian stages) Waukesha biota fossil site in southeast Wisconsin. This arthropod was first discovered alongside the biota in 1985, but was not fully described until October 2022. This creature was recognized and described as a possible early mandibulate (the grouping of arthropods including crustaceans and hexapods). This description is very important as much of the fauna of the biota remain undescribed, and its discovery has allowed for paleontologists to get a better grasp of the diversity of the arthropod fauna at the site. Multiple phylogenetic analyses were performed, and it was found that this arthropod forms a previously undiscovered clade with the Devonian stem-arthropod ''Captopodus'', and the somewhat enigmatic group Thylacocephala. ''Acheronauta'' has been assessed as a possible basal mandibulate, which are distinguished from other arthropods due to the presen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tanazios
''Tanazios'' is a genus of Silurian stem-mandibulate from the Coalbrookdale Formation of England. Description ''Tanazios'' has a head shield that is semicircular in shape, divided into a fringe and an axial (central) region. The fringe margins meet somewhat abruptly at the front of the shield, with a long projection pointing from their back corners and six pairs of horn-like structures at the sides. The axial region is semi-ovoid in shape, around 3 times wider than long, and bears a wide furrow running down its length. At the sides there is a narrow ledge which pinches out towards the back and continues as the inner trunk pleurae. No eyes seem to be present. The hypostome is subrectangular and extends from the antennulae to the mandibular gnathobases, with an anterior margin bearing four small spines and a convex posterior margin with a lip-like structure which may be the labrum. The antennulae are very short and uniramous, with the antennae being around five times longer a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sir David Attenborough
Sir David Frederick Attenborough (; born 8 May 1926) is an English broadcaster, biologist, natural historian and writer. He is best known for writing and presenting, in conjunction with the BBC Studios Natural History Unit, the nine nature documentary series forming the ''Life'' Collection, a comprehensive survey of animal and plant life on Earth. Attenborough was a senior manager at the BBC, having served as controller of BBC Two and director of programming for BBC Television in the 1960s and 1970s. First becoming prominent as host of '' Zoo Quest'' in 1954, his filmography as writer, presenter and narrator has spanned eight decades; it includes ''Natural World'', '' Wildlife on One'', the ''Planet Earth'' franchise, '' The Blue Planet'' and its sequel. He is the only person to have won BAFTA Awards in black and white, colour, high-definition, 3D and 4K resolution. Over his life he has collected dozens of honorary degrees and awards, including three Emmy Awards for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chengjiangocaris
''Chengjiangocaris'' is an extinct genus of fuxianhuiid arthropod known from the Cambrian of South China. It contains two species, ''C. longiformis'' which was described in 1991. ''C. kunmingensis'' was described in 2013 by Javier Ortega-Hernández and colleagues. One specimen of ''C. kunmingensis'' shows detailed evidence of a nervous system. The nervous system of the chengjiangocaris is and has always been very complex to understand but a recent discovery of the ladder like ventral nerval cords and segmental ganglia of the related chengjiangocaris together with the brain provides the most comprehensive reconstruction of any lower Cambrian arthropod. Anatomy ''C. kunmingensis'' has 20 anterior trunk tergites and up to 16 narrow anterior tergites. Phylogeny After References Further reading *Jie Yang et al.Fuxianhuiid ventral nerve cord and early nervous system evolution in Panarthropoda - abstract Proceedings of the National Academy of Sciences ''Proceedings of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fuxianhuia
''Fuxianhuia'' is a genus of Lower Cambrian fossil arthropod known from the Chengjiang fauna in China. Its purportedly primitive features have led to it playing a pivotal role in discussions about the euarthropod stem group. Nevertheless, despite being known from many specimens, disputes about its morphology, in particular its head appendages, have made it one of the most controversial of the Chengjiang taxa, and it has been discussed extensively in the context of the arthropod head problem. The genus is named after Fuxian Lake (''Fuxian Hu''), where it was unearthed. Its specific name (zoology), specific name ''wikt:protensus, protensa'' refers to its extended trunk. Description Complete ''Fuxianhuia'' specimens are approximately 4 centimetres long. The anterior of ''Fuxianhuia'' is encased in an oval sclerite, from which two stalked eyes emerge. Inserting directly behind this sclerite, on the head shield proper, are two stout antennae. When the head of ''Fuxianhuia'' was ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fuxianhuiida
Fuxianhuiida is an extinct clade of arthropods from the Cambrian of China. All currently known species are from Cambrian Series 2 aged deposits in Yunnan, Yunnan Province, including the Maotianshan Shales, Chengjiang biota. Although historically suggested to be members of the arthropod stem group recent research has suggested that they may be closely related to Mandibulata, mandibulates. Many specimens are known with exceptional soft tissue preservation, including preserved guts and Nervous tissue, neural tissue, which given their Basal (phylogenetics), basal phylogenetic position makes them important in understanding the evolution of Arthropoda as a whole. They reach a size of up to 15 cm, and are interpreted as Benthic zone, benthic predators and scavengers. The Fuxianhuiid exoskeleton is unmineralised, and the number of Tergum, tergites ranges from 15 to over 40. The Cephalon (arthropod head), cephalon is covered by a head shield and contains stalked eyes connected by the S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canadaspis
''Canadaspis'' ("Shield of Canada") is an extinct genus of bivalved Cambrian marine arthropod, known from North America and China. They are thought to have been benthic feeders that moved mainly by walking and possibly used its biramous appendages to stir mud in search of food. They have been placed within the Hymenocarina, which includes other bivalved Cambrian arthropods. Description ''Canadaspis'' ''perfecta'' The bivalved carapaces of ''Canadaspis'' ''perfecta'' are typically in length, which taper towards the front end. The head had a small pair of eyes borne on short stalks. Between the eyes is a forward pointing spine, as well as a pair of short antennae, which appear to lack segmentation. Similar antennae are known from '' Waptia'', and are probably homologous to the hemi-ellipsoid bodies of crustaceans, and thus likely have an olfactory function. The head also has another pair of larger, segmented antennae, probably with more than 12 segments, the segments increased ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pancrustacea
Pancrustacea is the clade that comprises all crustaceans and all hexapods (insects and relatives). This grouping is contrary to the Atelocerata hypothesis, in which Hexapoda and Myriapoda are sister taxa, and Crustacea are only more distantly related. As of 2010, the Pancrustacea taxon was considered well accepted, with most studies recovering Hexapoda within Crustacea. The clade has also been called Tetraconata, referring to having a four-part cone in the ommatidium. The term "Tetraconata" is preferred by some scientists in order to avoid confusion with the use of "pan-" to indicate a clade that includes a crown group and all of its stem group representatives. Molecular studies A monophyletic Pancrustacea has been supported by several molecular studies, in most of which the subphylum Crustacea is paraphyletic with regard to hexapods (that is, that hexapods, including insects, are derived from crustacean ancestors). This means that within Pancrustacea, only some members are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
