| Youngibelus Temporal range: Jurassic | |
|---|---|
 | |
| Two Youngibelus, showing the male on the bottom with an epirostrum | |
| Scientific classification | |
| Kingdom: | |
| Phylum: | |
| Class: | |
| (unranked): | |
| Family: | |
| Subfamily: | |
| Genus: | Youngibelus Riegraf, 1980 |
| Type species | |
| †Youngibelus tubularis | |
| Other species | |
| |
Youngibelus is a genus of belemnite, an extinct group of cephalopods. [1]
Y. tubularis and Y. levis are two species from Toarcian aged rocks in Yorkshire. It has been suggested that these two species are actually morphs of the same species. The divergence in morphology occurs in the gerontic stage of development, characterised by differences in the rostrum. In Y. levis, the rostrum thickens, whilst in Y. tubularis, an epirostrum develops. Peter Doyle proposed that the epirostrum developed as either a counterbalance for a sexual adaptation, or for display in courtship. [2]
Trilobites are extinct marine arthropods that form the class Trilobita. Trilobites form one of the earliest known groups of arthropods. The first appearance of trilobites in the fossil record defines the base of the Atdabanian stage of the Early Cambrian period and they flourished throughout the lower Paleozoic before slipping into a long decline, when, during the Devonian, all trilobite orders except the Proetida died out. The last extant trilobites finally disappeared in the mass extinction at the end of the Permian about 252 million years ago. Trilobites were among the most successful of all early animals, existing in oceans for almost 270 million years, with over 22,000 species having been described.
Belemnoids are an extinct group of marine cephalopod, very similar in many ways to the modern squid and closely related to the modern cuttlefish. Like them, the belemnoids possessed an ink sac, but, unlike the squid, they possessed ten arms of roughly equal length, and no tentacles. The name "belemnoid" comes from the Greek word βέλεμνον, belemnon meaning "a dart or arrow" and the Greek word είδος, eidos meaning "form".
Ceratopsia or Ceratopia is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurassic. The earliest known ceratopsian, Yinlong downsi, lived between 161.2 and 155.7 million years ago. The last ceratopsian species, Triceratops prorsus, became extinct during the Cretaceous–Paleogene extinction event, 66 million years ago.
Temnodontosaurus is an extinct genus of ichthyosaur from the Early Jurassic period. They lived between 200 and 175 million years ago (Hettangian-Toarcian) in what is now Western Europe and possibly Chile. It lived in the deeper areas of the open ocean. University of Bristol paleontologist Jeremy Martin described the genus Temnodontosaurus as "one of the most ecologically disparate genera of ichthyosaurs," although the number of valid Temnodontosaurus species has varied over the years.
Teleosaurus is an extinct genus of teleosaurid crocodyliform found in the Middle Jurassic Calcaire de Caen Formation of France. It was approximately 3 metres (10 ft) in length and weighed 60 kg (130 lb). The holotype is MNHN AC 8746, a quarter of a skull and other associated postcranial remains, while other fragmentary specimens are known. The type species is T. cadomensis, but a second species, T. geoffroyi may also exist. It was previously considered a wastebasket taxon, with many other remains assigned to the genus.
Megateuthis gigantea is the largest known belemnite species, reaching about 50 mm and 700mm in maximum diameter and length of rostrum, respectively. The fossil remains were discovered in Europe and Asia.
Cylindroteuthis is a genus of belemnite that lived from the Early Jurassic to the Early Cretaceous. Its fossils have been found in Asia, Europe, North America, and New Zealand.
Hibolithes is a genus of belemnite that lived from the Middle Jurassic to the Early Cretaceous, and has been found in Antarctica, Greenland, Iran, Europe, South America, and New Zealand. In 2020, this genus was found in the Pedawan Formation in Sarawak, on the island of Borneo (Malaysia).
Belemnitella is a genus of belemnite from the Late Cretaceous of Europe and North America. Belemnitella was a squidlike animal, probably related to the ancestors of modern squids and cuttlefish. The shell was internal. The rostrum or guard is found the most often and possesses a distinctive slit at its ventral surface and a ridge on the dorsal surface. The phragmocone has a small protoconch at its tip, and fit into the cavity and the guard. It also had septa and a ventral siphuncle within the phragmocone, projecting forward as a beak-like blade.
Belemnotheutis is an extinct coleoid cephalopod genus from the middle and upper Jurassic, related to but morphologically distinct from belemnites. Belemnotheutis fossils are some of the best preserved among coleoids. Remains of soft tissue are well-documented in some specimens, even down to microscopic muscle tissue. In 2008, a group of paleontologists even recovered viable ink from ink sacs found in several specimens.
Hauffiosaurus is an extinct genus of Early Jurassic pliosaurid plesiosaur known from Holzmaden of Germany and from Yorkshire of the United Kingdom. It was first named by Frank Robin O’Keefe in 2001 and the type species is Hauffiosaurus zanoni. In 2011, two additional species were assigned to this genus: H. longirostris and H. tomistomimus.
Acrocoelites is a genus of belemnite, an extinct group of cephalopods.
Belemnitina is a suborder of belemnites, an extinct group of cephalopods. They have been identified as the oldest of all the belemnites and are likely the stockgroup for them. They were extant from the early Jurassic to the early Cretaceous. Their geographic distribution was mostly limited to Europe, although specimens have been described in Japan suggesting they may have been more widespread than previously thought.
Leptosuchus is an extinct genus of leptosuchomorph phytosaur with a complex taxonomical history. Fossils have been found from the Dockum Group and lower Chinle Formation outcropping in Texas, New Mexico, and Arizona, USA, and date back to the Carnian stage of the Late Triassic.
The Cornbrash Formation is a Middle Jurassic geological formation in England. It ranges in age from Bathonian to Callovian, the uppermost part of the Middle Jurassic. Dinosaur remains are among the fossils that have been recovered from the formation, although none have yet been referred to a specific genus. The name Cornbrash is an old English agricultural name applied in Wiltshire to a variety of loose rubble or brash which, in that part of the country, forms a good soil for growing corn. The name was adopted by William Smith for a thin band of shelly limestone which, in the south of England, breaks up in the manner indicated. Although only a thin group of rocks, it is remarkably persistent; it may be traced from Weymouth to the Yorkshire coast, but in north Lincolnshire it is very thin, and probably dies out in the neighborhood of the Humber. It appears again, however, as a thin bed in Gristhorpe Bay, Cayton Bay, Wheatcroft, Newton Dale and Langdale. In the inland exposures in Yorkshire it is difficult to follow on account of its thinness, and the fact that it passes up into dark shales in many places the so-called clays of the Cornbrash, with Avicula echinata. The Cornbrash is of little value for building or road-making, although it is used locally; in the south of England it is not oolitic, but in Yorkshire it is a rubbly, marly, frequently ironshot oolitic limestone. In Bedfordshire it has been termed the Bedford limestone.
The Whitby Mudstone is a Toarcian geological formation in Yorkshire and Worcestershire, England. The formation, part of the Lias Group, is present in the Cleveland and Worcester Basins and the East Midlands Shelf.
Belemnitida is an extinct order of squid-like cephalopods that existed from the Late Triassic to Late Cretaceous. Unlike squid, belemnites had an internal skeleton that made up the cone. The parts are, from the arms-most to the tip: the tongue-shaped pro-ostracum, the conical phragmocone, and the pointy guard. The calcitic guard is the most common belemnite remain. Belemnites, in life, are thought to have had 10 hooked arms and a pair of fins on the guard. The chitinous hooks were usually no bigger than 5 mm (0.20 in), though a belemnite could have had between 100 and 800 hooks in total, using them to stab and hold onto prey.
Calcinus tubularis is a species of hermit crab. It is found in the Mediterranean Sea and around islands in the Atlantic Ocean, where it lives below the intertidal zone. Its carapace, eyestalks and claws are marked with numerous red spots. C. tubularis and its sister species, C. verrilli, are the only hermit crabs known to show sexual dimorphism in shell choice, with males using normal marine gastropod shells, while females use shells of gastropods in the family Vermetidae, which are attached to rocks or other hard substrates.
All extant cephalopods have a two-part beak, or rostrum, situated in the buccal mass and surrounded by the muscular head appendages. The dorsal (upper) mandible fits into the ventral (lower) mandible and together they function in a scissor-like fashion. The beak may also be referred to as the mandibles or jaws.
Saltwick Bay is a north-east facing bay approximately one mile (1.6 km) to the east of Whitby, on the east coast of North Yorkshire, England. The bay contains the Saltwick Nab alum quarries, listed under the Ancient Monuments and Archaeological Areas Act 1979. The bay is part of the Saltwick Formation and known for its collections of fossils. The SS Rohilla hospital ship sank in the bay in 1914, and the fishing trawler Admiral Van Tromp was shipwrecked there in 1976. The bay is accessible through Whitby Holiday Park.
 | This prehistoric cephalopod-related article is a stub. You can help Wikipedia by expanding it. |
