Lagenanectes Temporal range: | |
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Lagenanectes richterae, skull reconstruction in right lateral view | |
Scientific classification | |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Superorder: | † Sauropterygia |
Order: | † Plesiosauria |
Family: | † Elasmosauridae |
Genus: | † Lagenanectes |
Species: | †L. richterae |
Binomial name | |
†Lagenanectes richterae Sachs, Hornung & Kear, 2017 | |
Lagenanectes is a genus of elasmosaurid plesiosaur from the Lower Cretaceous, found in Lower Saxony, Germany. The only species, Lagenanectes richterae, was first described in 2017, and is regarded as one of the best-preserved plesiosaur fossils from this geological age in Europe. [1] Lagenanectes is one of the earliest elasmosaurids. The holotype is an incomplete skeleton, comprising large parts of the skull, some neck and tail vertebrae as well as ribs and part of the limbs. A length of about 8 meters (26 feet) has been estimated. [1]
The well-preserved holotype specimen of Lagenanectes richterae (specimen number BGR Ma 13328) was found in the disused Moorberg clay pit near Sarstedt by private collectors in 1964. [2] The exact horizon is unknown (the age of the fossils might be lower Hauterivian to lower Barremian, but most probably is upper Hauterivian). The fossils were later given to the Geological Survey at Hannover, where Professor Sickenberg identified them as elasmosaurid remains. [2] They have subsequently been transferred to the Lower Saxony State Museum in Hannover, where part of the specimen is now on display. [3] However, it was not until some 50 years later, in 2017, that Sven Sachs, Jahn J. Hornung and Benjamin P. Kear studied the fossil in detail and erected Lagenanectes as a new, monotypic genus. [4]
The name Lagenanectes literally means "Leine swimmer" and refers to both, the Leine river which passes Sarstedt, and to the swimming life style of this marine reptile. The species name richterae honours Annette Richter, chief curator of the Natural History department at the Lower Saxony State Museum in Hannover, for her contributions to the palaeontological exploration of Lower Saxony.
The holotype of Lagenanectes richterae was a fully grown individual. This is indicated by the ossification of both the cranial bones and the vertebrae and neural arches. [1]
The front part of the lower jaw of Lagenanectes richterae shows some anatomical features which are unique in plesiosaurs (autapomorphies): The alveols are placed sidewards and a platform is present on the underside of the lower jaw that bears prominent dents. The skull of Lagenanectes shows a rounded snout that is accompanied by some grooves on the upper side. These grooves may have accommodated electroreceptors to locate the prey. The neck vertebrae of Lagenanectes are square-shaped and lack a notch on the lower side of the articular surfaces of the vertebral centra, which is characteristic for other elasmosaurs. [5]
The study by Sachs and colleagues demonstrated that Lagenanectes richterae was an early member of the elasmosaurids. Following their cladistic analysis, Lagenanectes was most closely related to the "Speeton Clay plesiosaur" (a yet undescribed plesiosaur from the Hauterivian of England, and to Callawayasaurus from the Aptian of Colombia. [1]
The occiput and the first neck vertebra of the holotype of Lagenanectes richterae show pathological alterations of the bony structure. They may have been caused by an infection. [1] [6]
Elasmosaurus (;) is a genus of plesiosaur that lived in North America during the Campanian stage of the Late Cretaceous period, about 80.5 million years ago. The first specimen was discovered in 1867 near Fort Wallace, Kansas, US, and was sent to the American paleontologist Edward Drinker Cope, who named it E. platyurus in 1868. The generic name means "thin-plate reptile", and the specific name means "flat-tailed". Cope originally reconstructed the skeleton of Elasmosaurus with the skull at the end of the tail, an error which was made light of by the paleontologist Othniel Charles Marsh, and became part of their "Bone Wars" rivalry. Only one incomplete Elasmosaurus skeleton is definitely known, consisting of a fragmentary skull, the spine, and the pectoral and pelvic girdles, and a single species is recognized today; other species are now considered invalid or have been moved to other genera.
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Libonectes is an extinct genus of sauropterygian reptile belonging to the plesiosaur order. It is known from specimens found in the Britton Formation of Texas (USA) and the Akrabou Formation of Morocco, which have been dated to the lower Turonian stage of the late Cretaceous period.
Umoonasaurus is an extinct genus of plesiosaur belonging to the family Leptocleididae. This genus lived approximately 115 million years ago during the Late Cretaceous period, in shallow seas covering parts of what is now Australia. It was a relatively small animal around 2.5 metres (8.2 ft) long. An identifying trait of Umoonasaurus is three crest-ridges on its skull.
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Aphrosaurus was an extinct genus of plesiosaur from the Maastrichtian. The type species is Aphrosaurus furlongi, named by Welles in 1943. The holotype specimen was discovered in the Moreno Formation in Fresno County, California in 1939 by rancher Frank C. Piava. A second specimen - LACM 2832 - was also found in the same formation and initially diagnosed as a juvenile of the same species, but has since been removed from the genus.
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Eromangasaurus is an extinct genus of elasmosaurid known from northern Queensland of Australia.
Albertonectes is an extinct genus of elasmosaurid plesiosaur known from the Late Cretaceous Bearpaw Formation of Alberta, Canada. It contains a single species, Albertonectes vanderveldei. Albertonectes is the longest elasmosaur, and more generally plesiosaur, known to date both in neck and total body length.
This timeline of plesiosaur research is a chronologically ordered list of important fossil discoveries, controversies of interpretation, taxonomic revisions, and cultural portrayals of plesiosaurs, an order of marine reptiles that flourished during the Mesozoic Era. The first scientifically documented plesiosaur fossils were discovered during the early 19th century by Mary Anning. Plesiosaurs were actually discovered and described before dinosaurs. They were also among the first animals to be featured in artistic reconstructions of the ancient world, and therefore among the earliest prehistoric creatures to attract the attention of the lay public. Plesiosaurs were originally thought to be a kind of primitive transitional form between marine life and terrestrial reptiles. However, now plesiosaurs are recognized as highly derived marine reptiles descended from terrestrial ancestors.
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