The Jurassic is a geologic period and stratigraphic system that spanned from the end of the Triassic Period 201.4 million years ago (Mya) to the beginning of the Cretaceous Period, approximately 145 Mya. The Jurassic constitutes the middle period of the Mesozoic Era and is named after the Jura Mountains, where limestone strata from the period were first identified.
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting tail-like abdomen, usually hidden entirely under the thorax. They live in all the world's oceans, in freshwater, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers on each arm. They first appeared during the Jurassic period, around 200 million years ago.
The order Notostraca, containing the single family Triopsidae, is a group of crustaceans known as tadpole shrimp or shield shrimp. The two genera, Triops and Lepidurus, are considered living fossils, with similar forms having existed since the end of the Devonian, around 360 million years ago. They have a broad, flat carapace, which conceals the head and bears a single pair of compound eyes. The abdomen is long, appears to be segmented and bears numerous pairs of flattened legs. The telson is flanked by a pair of long, thin caudal rami. Phenotypic plasticity within taxa makes species-level identification difficult, and is further compounded by variation in the mode of reproduction. Notostracans are omnivores living on the bottom of temporary pools and shallow lakes.
Cryptoclididae is a family of medium-sized plesiosaurs that existed from the Middle Jurassic to the Early Cretaceous. They had long necks, broad and short skulls and densely packed teeth. They fed on small soft-bodied preys such as small fish and crustaceans. The earliest members of the family appeared during the early Bajocian, and they represented the dominant group of long-necked plesiosaurs during the latter half of the Jurassic.
Epicaridea is a former suborder of isopods, now treated as an infraorder in suborder Cymothoida. They are ectoparasites that inhabit other crustaceans, namely ostracods, copepods, barnacles and malacostracans. Epicarideans are found globally. Epicaridea are generally less well researched than other isopods.
Dromioidea is a superfamily of crabs mostly found in Madagascar. Dromioidea belongs the group Dromiacea, taxonomically ranked as a section, which is the most basal grouping of Brachyura crabs. Dromiacea likely diverged from the rest of Brachyura around the Late Triassic or Early Jurassic, and the earliest fossils attributable to the Dromioidea date from the Late Jurassic.
La Voulte-sur-Rhône is a commune in the Ardèche department in southern France.
Eryon is an extinct genus of decapod crustaceans from the Late Jurassic of Germany. Its remains are known from the Solnhofen limestone. It reached a length of around 10 cm (3.9 in), and may have fed on particulate matter on the sea bed.
The Solnhofen Limestone or Solnhofen Plattenkalk is a collective term for multiple Late Jurassic lithographic limestones in southeastern Germany, which is famous for its well preserved fossil flora and fauna dating to the late Jurassic (Kimmeridgian-Tithonian). The paleoenvironment is also often referred to as the Solnhofen Archipelago. The Solnhofen Archipelago was located at the northern edge of the Tethys Ocean as part of a shallow epicontinental sea and is firmly a part of the Mediterranean realm.
Eubrachyura is a group of decapod crustaceans comprising the more derived crabs. It is divided into two subsections, based on the position of the genital openings in the two sexes. In the Heterotremata, the openings are on the legs in the males, but on the sternum in females, while in the Thoracotremata, the openings are on the sternum in both sexes. This contrasts with the situation in other decapods, in which the genital openings are always on the legs. Heterotremata is the larger of the two groups, containing the species-rich superfamilies Xanthoidea and Pilumnoidea and all the freshwater crabs. The eubrachyura is well known for actively and constantly building its own burrows. The fossil record of the Eubrachyura extends back to the Cretaceous; the supposed Bathonian representative of the group, Hebertides jurassica, ultimately turned out to be Cenozoic in age.
Corystidae is a family of crabs, in its own superfamily, Corystoidea. It includes what was once thought to be the oldest Eubrachyuran fossil, Hebertides jurassica, thought to be dating from the Bathonian ; the species was subsequently reinterpreted as being Cenozoic in age. Corystidae contains ten extant and five extinct species in eight genera:
Eryonidae is a family of fossil decapod crustaceans which lived from the Upper Triassic to the Lower Cretaceous. It contains four genera: An aggregation of three unidentified eryonids was reported in 2012 inside a Late Jurassic ammonoid of the species Harpoceras falciferum; they represent the earliest evidence of gregarious behaviour in decapods.
Koelga is an extinct genus of prawn in the order Decapoda. It contains the species Koelga curvirostris and Koelga muensteri.
Hefriga is an extinct genus of shrimp in the order Decapoda. It contains three species, and lived in the Jurassic period.
Cyclida is an extinct order of crab-like fossil arthropods that lived from the Carboniferous to the Jurassic and possibly Cretaceous. Their classification is uncertain, but they are generally interpreted as crustaceans, likely belonging to the superclass Multicrustacea.
Eryma is a genus of fossil lobster-like crustaceans, containing 44 species. Two were preserved in the Solnhofen Limestone in Germany. 42 rest of them were found worldwide oldest to youngest between the Jurassic.
Cancrinos is a genus of fossil crustaceans closely allied with the slipper lobsters. One species is known, C. claviger from the Jurassic of southern Germany.
Pleurosternidae is an extinct family of freshwater turtles belonging to Paracryptodira. They are definitively known from the Late Jurassic to Early Cretaceous (Albian) of Western Europe and North America.
Achelonia is an extinct genus of marine thalassochelydian turtle. Its type species is Achelonia formosa. Fossils are known from the Upper Jurassic of Wattendorf, Germany, within Cerin, France, and also in England. Material from England was originally considered to belong to the separate genus Enaliochelys and species Enaliochelys chelonia, named by Harry Govier Seeley in 1869 for a partial disarticulated skeleton from the early Kimmeridgian of the Kimmeridge Clay in Cambridgeshire. The synonymy was recognised in 2020.
Burkesuchus is an extinct genus of basal neosuchians from the Upper Jurassic (Tithonian)-aged Toqui Formation of southern Chile. The genus is currently represented by a single species B. mallingrandensis, named and described in 2021 on the basis of the holotype and additional referred specimens. Burkesuchus mallingrandensis was noticeably small being around an estimated 70 cm in length. The cranium is dorsoventrally depressed and transversely wide posteriorly and distinguished by a posteroventrally flexed wing-like squamosal. Burkesuchus was a small carnivore likely on invertebrates animals such as insects, crustaceans and may had feed on small aquatic vertebrates like fish. B. mallingrandensis did not have the ability to feed on large prey items or tear large chunks of meat like modern day crocodiles do. The holotype SQO.PV 17700, consist of a cervical neural arch, partial neurocranium, four dorsal vertebrae, right scapula, a right coracoid, right humerus, a ulna, left ischium, distal end of the right femur, one cervical and two dorsal osteoderms. The paratype SQO.PV 17701 fossil remains consist of a nearly complete right femur, two doral vertebrae and one dorsal osteoderm. The fossils was discovered in 2014 but was described as a new genus and species on July 23, 2021.
