Lagen anectes
| Lagen anectes | ||||||||||
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Reconstruction of the skull of Lagenanectes richterae |
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| Temporal occurrence | ||||||||||
| Lower Cretaceous (probably Upper Hauterivium ) | ||||||||||
| 133.1 to 130.7 million years | ||||||||||
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| Scientific name | ||||||||||
| Lagen anectes | ||||||||||
| Sachs , Hornung & Kear , 2017 | ||||||||||
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Lagenanectes is a genus of plesiosaurs from the Elasmosauridae family thatlived inwhat is now Germany during the Early Cretaceous . The only species is Lagenanectes richterae . The genus was described in 2017 and is one of the earliest representatives of the elasmosaurs. The holotype is an incomplete skeleton which includes large parts of the skull, some cervical and caudal vertebrae, as well as ribs and parts of the extremities. The body length is estimated at 8 m.
Research history
The holotype of Lagenanectes richterae (copy number BGR Ma 13328) was discovered and recovered in the summer of 1964 by fossil collectors (including K. Wiedenroth and FO Finzel) in the former clay pit Moorberg near Sarstedt in Lower Saxony . The exact horizon is unknown, so that there is some uncertainty about the geological age, which can lie between the lower Hauterivian and lower Barremian . The upper skin ivium is assumed to be the most likely age. The skeletal remains were handed over to the State Office for Soil Research in Hanover , where Professor Sickenberg recognized them as elasmosaurs. The remains were later given on permanent loan to the Lower Saxony State Museum in Hanover, where they have since formed part of the collection.
Naming
Lagenanectes richterae was in 2017 by Sven Sachs, Jahn J. Hornung and Benjamin P. Kear described . The name Lagenanectes literally means "Leine-Schwimmer" and refers to the river Leine , as well as the swimming mode of movement of the marine reptile. The species name richterae honors the senior curator for natural history at the Lower Saxony State Museum in Hanover , Annette Richter, for her services to paleontological research in Lower Saxony .
Age of the holotype
The holotype of Lagenanectes richterae is a fully grown animal. This can be seen from the fact that both the bones of the skull and the vertebral arches and vertebral bodies are fused together.
Anatomical features
The lower jaw of Lagenanectes richterae shows a number of anatomical features that are unique to plesiosaurs ( autapomorphies ). This includes having the teeth in the front part of the lower jaw laterally. In addition, distinctive depressions are formed in this area on the underside of the jaw. The skull of Lagenanectes has a strongly rounded tip of the snout and several pits on the upper side, in which electroreceptors could have been located to locate the prey. The cervical vertebrae of Lagenanectes have a square shape and they lack the depression in the lower edge of the anterior and posterior articular surfaces of the vertebral bodies, which is typical for many elasmosaurs .
Pathological changes
The occiput and the first cervical vertebra of the holotype of Lagenanectes richterae show disease-related changes in the bone structure. This may have been caused by inflammation.
Taxonomy
The study by Sachs and colleagues found that Lagenanectes richterae was an early representative of the elasmosaurs. According to a cladistic analysis, Lagenanectes is most closely related to the "Speeton Clay plesiosaur" (a previously undescribed plesiosaur from the Hauterivium of England) and to Callawayasaurus from the Aptium of Colombia .
literature
- ↑ a b c d e f Sven Sachs, Jahn J. Hornung, Benjamin P. Kear: A new basal elasmosaurid (Sauropterygia: Plesiosauria) from the Lower Cretaceous of Germany . In: Journal of Vertebrate Paleontology . Online edition, 2017, p. E1301945. doi : 10.1080 / 02724634.2017.1301945 .
- ↑ a b Erika Finzel: Plesiosaurus fund in the Lower Cretaceous . In: Aufschluss . 11, 1964, p. 307.
- ↑ Marine dinosaur fossil discovered in Lower Saxony . In: scinexx.de . Retrieved November 7, 2017.
- ↑ Spectacular dinosaur find: New species of marine dinosaur discovered in Lower Saxony . In: geohorizon.de . Retrieved November 7, 2017.
- ^ S. Sachs, BP Kear: Fossil Focus: Elasmosaurs . In: Palaeontology Online . 5, 2015, pp. 1–8.