| Palaeoscolex | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Class: | † Palaeoscolecida |
| Family: | † Palaeoscolecidae |
| Genus: | † Palaeoscolex |
Palaeoscolex is the type genus of the Palaeoscolecid worms, and served as a wastebasket taxon. [1] until its taxonomy was revised and many of its taxa assigned to Wronascolex . [2]
The type and only unequivocal species is P. piscatorum, known from mid-trunk segments. [3] [4]
The Cambrian Period was the first geological period of the Paleozoic Era, and of the Phanerozoic Eon. The Cambrian lasted 55.6 million years from the end of the preceding Ediacaran Period 541 million years ago (mya) to the beginning of the Ordovician Period 485.4 mya. Its subdivisions, and its base, are somewhat in flux. The period was established as "Cambrian series" by Adam Sedgwick, who named it after Cambria, the Latin name for 'Cymru' (Wales), where Britain's Cambrian rocks are best exposed. Sedgwick identified the layer as part of his task, along with Roderick Murchison, to subdivide the large "Transition Series", although the two geologists disagreed for a while on the appropriate categorization. The Cambrian is unique in its unusually high proportion of lagerstätte sedimentary deposits, sites of exceptional preservation where "soft" parts of organisms are preserved as well as their more resistant shells. As a result, our understanding of the Cambrian biology surpasses that of some later periods.
The Ordovician is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period 485.4 million years ago (Mya) to the start of the Silurian Period 443.8 Mya.
Jerdon's courser is a nocturnal bird belonging to the pratincole and courser family Glareolidae endemic to India. The bird was discovered by the surgeon-naturalist Thomas C. Jerdon in 1848 but not seen again until its rediscovery in 1986. This courser is a restricted-range endemic found locally in India in the Eastern Ghats of Andhra Pradesh. It is currently known only from the Sri Lankamalleswara Wildlife Sanctuary, where it inhabits sparse scrub forest with patches of bare ground.
Markuelia is a genus of fossil worm-like bilaterian animals allied to Ecdysozoa and known from strata of Lower Cambrian to Lower Ordovician age containing five species.
Cryolophosaurus is a genus of large theropod dinosaur known from only a single species Cryolophosaurus ellioti, from the early Jurassic of Antarctica. It was about 6.5 metres (21.3 ft) long and 465 kilograms (1,025 lb) in weight, making it one of the largest theropods of its time. Individuals of this species may have grown even larger, because the only known specimen probably represents a sub-adult. Cryolophosaurus is known from a skull, a femur and other material, the skull and femur of which have caused its classification to vary greatly. The femur possesses many primitive characteristics that have classified Cryolophosaurus as a dilophosaurid or a neotheropod outside of Dilophosauridae and Averostra, whereas the skull has many advanced features, leading the genus to be considered a tetanuran, an abelisaurid, a ceratosaur and even an allosaurid. Cryolophosaurus is currently considered to be a derived neotheropod, close to Averostra.
The biodiversity of New Zealand, a large island country located in the south-western Pacific Ocean, is varied and distinctive. The species of New Zealand accumulated over many millions of years as lineages evolved in the local circumstances. New Zealand's pre-human biodiversity exhibited high levels of species endemism, but has experienced episodes of biological turnover. Global extinction approximately 65 Ma resulted in the loss of fauna such as non-avian dinosaurs, pterosaurs and marine reptiles e.g. mosasaurs, elasmosaurs and plesiosaurs. The ancient fauna is not well known, but at least one species of terrestrial mammal existed in New Zealand around 19 Ma. For at least several million years before the arrival of human and commensal species, the islands had no terrestrial mammals except for bats and seals, the main component of the terrestrial fauna being insects and birds. Recently—since c. 1300 CE—a component has been introduced by humans, including many terrestrial mammals.
The sapayoa or broad-billed sapayoa is a suboscine passerine found in lowland rainforests in Panama and north-western South America. As the epithet aenigma implies, its relationships have long been elusive. It is easy to overlook, but appears to be common in a wide range and is not considered threatened by the IUCN.
The Emu Bay Shale is a geological formation in Emu Bay, South Australia, containing a major Konservat-Lagerstätte. It is one of two in the world containing Redlichiidan trilobites. The Emu Bay Shale is dated as Cambrian Series 2, Stage 4, correlated with the upper Botomian Stage of the Lower Cambrian.
The Andaman worm snake is a species of harmless blind snake in the family Gerrhopilidae. The species is endemic to the Andaman Islands. No subspecies are currently recognized.
A number of assemblages bear fossil assemblages similar in character to that of the Burgess Shale. While many are also preserved in a similar fashion to the Burgess Shale, the term "Burgess Shale-type fauna" covers assemblages based on taxonomic criteria only.
Gondwana or Gondwanaland was a supercontinent that formed during the late Neoproterozoic and began to break up during the Jurassic, with the final stages of breakup, including the opening of the Drake Passage separating South America and Antarctica occurring during the Paleogene. Gondwana was not considered a supercontinent by the earliest definition, since the landmasses of Baltica, Laurentia, and Siberia were separated from it.
Ancalagon minor is an extinct priapulid worm known from the Cambrian Burgess Shale.
Archaeopriapulida is a group of priapulid-like worms known from Cambrian lagerstätte. The group is closely related to, and very similar to, the modern Priapulids. It is unclear whether it is mono- or polyphyletic. Despite a remarkable morphological similarity to their modern cousins, they fall outside of the priapulid crown group, which is not unambiguously represented in the fossil record until the Carboniferous. They are probably closely related or paraphyletic to the palaeoscolecids; the relationship between these basal worms is somewhat unresolved.
The palaeoscolecids are a group of extinct ecdysozoan worms resembling armoured priapulids. They are known from the Lower Cambrian to the late Silurian; they are mainly found as disarticulated sclerites, but are also preserved in many of the Cambrian lagerstätten. They take their name from the typifying genus Palaeoscolex.
Cricocosmia is a genus of palaeoscolecid worm from the Early Cambrian Chengjiang biota.
Louisella is a genus of worm known from the Middle Cambrian Burgess Shale. It was originally described by Charles Walcott in 1911 as a holothurian echinoderm, and represents a senior synonym of Miskoia, which was originally described as an annelid. 48 specimens of Louisella are known from the Greater Phyllopod bed, where they comprise < 0.1% of the community. It has been stated to have palaeoscolecid-like sclerites, though this is not in fact the case.
Scolecofurca is a genus of stem-group priapulid worm dating from the Middle Cambrian period approximately 505 million years ago.
Tabelliscolex is a genus of palaeoscolecid worm from the Early Cambrian Chengjiang biota that comprises two species, T. hexagonus and T. maanshanensis.
Scathascolex is a genus of palaeoscolecid worm known from the middle Cambrian Burgess Shale. It is the only taxon in that famous locality to exhibit the phosphatic plates that characterize palaeoscolecids, and has certain unusual characteristics – it does not have the multiple sizes of tessellating plates more typical of palaeoscolecids, and has more tail hooks than is the norm. Nevertheless, it is clearly a close relative of Palaeoscolex and Wronascolex.
 | This prehistoric protostome article is a stub. You can help Wikipedia by expanding it. |