Sunday, August 27, 2017

[Paleontology • 2017] Lagenanectes richterae • A New Basal Elasmosaurid (Sauropterygia: Plesiosauria) from the Lower Cretaceous of Germany


Lagenanectes richterae
 Sachs, Hornung & Kear, 2017


ABSTRACT
Here we report on a new basal elasmosaurid plesiosaurian, Lagenanectes richterae, gen. et sp. nov., from the Lower Cretaceous (probably Upper Hauterivian) of Germany. The material includes a partial skull (cranium and mandible), the atlas-axis complex, additional cervical vertebrae, caudal vertebrae, an ilium, and limb elements. The basioccipital and atlas intercentrum are pathologically deformed, probably due to an osteomyelitic infection. Two potential autapomorphies were found in the mandible: (1) the alveolar margin at the symphysis is laterally expanded with the rostral-most alveoli being markedly procumbent and situated along the lateral margins of the dentaries; and (2) the ventral midline at the symphysis is produced into a prominent wedge-shaped platform indented by numerous irregular pits. Lagenanectes richterae, gen. et sp. nov., also shows a number of typical elasmosaurid traits, including a longitudinal lateral ridge on the cervical vertebral centra (although a ventral notch is absent) and teeth with oval cross-sections. Lagenanectes richterae, gen. et sp. nov., is one of the best-preserved plesiosaurians from the Lower Cretaceous of Europe.


FIGURE 4. Lagenanectes richterae, gen. et sp. nov., BGR Ma 13328, holotype, reconstruction of the skull showing the preserved portions (shaded) in A, lateral and B, ventral views. The missing parts are reconstructed based on Libonectes spp. (partly after Carpenter 1997:figs. 2, and 5).
 Abbreviations: bo, basioccipital; den, dentary; in, internal naris; mx, maxilla; pal, palatine; pmx, premaxilla; ps, parasphenoid; pt, pterygoid; qu, quadrate; v, vomer. Scale bar equals 5 cm.



FIGURE 3. Lagenanectes richterae, gen. et sp. nov., BGR Ma 13328, holotype, cranium in ventral view. A, photograph; B, interpretive illustration. Dotting: sedimentary matrix.
 Abbreviations: dlf, dental lamina foramen; in, internal naris; pal, palatine; pmx, premaxilla; ps, parasphenoid; pt, pterygoid; rpt, replacement tooth; v, vomer. Scale bar equals 5 cm


SYSTEMATIC PALEONTOLOGY

SAUROPTERYGIA Owen, 1860
PLESIOSAURIA Blainville, 1835
ELASMOSAURIDAE Cope, 1869

LAGENANECTES, gen. nov.

Etymology:— Lagenanectes, ‘Leine swimmer,’ composed from Lagena, the medieval Old High German name of the Leine River, which passes the vicinity of Sarstedt and forms a major local hydrographic feature, and -nectes from latinized Greek: ‘o nektes’ - ‘swimmer’.

Type Species:— Lagenanectes richterae, sp. nov.

LAGENANECTES RICHTERAE, sp. nov.
Plesiosaurus elasmosaurus (Finzel, 1964:307, nomen nudum).
Elasmosaurus’ (Harms, 1982:2)
Elasmosaurus sp. (Zawischa, 1987:85)
Skelettrest eines Elasmosauriers (Sachs, 2000:33)
Schädelreste, Zähne und Wirbel eines Elasmosauriers (Sachs, 2011:12)
New basal elasmosaurid (Sachs et al., 2015:131)

Etymology:— The species epithet richterae is a patronym for Dr. Annette Richter, Niedersächsisches Landesmuseum, Hannover, honoring her various contributions and outstanding dedication to the vertebrate paleontology of Lower Saxony.

FIGURE 13. Life reconstruction of Lagenanectes richterae, gen. et sp. nov. Artwork by Frederik Spindler, 2015.



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Sven Sachs, Jahn J. Hornung and Benjamin P. Kear. 2017. A New Basal Elasmosaurid (Sauropterygia: Plesiosauria) from the Lower Cretaceous of Germany. Journal of Vertebrate Paleontology. DOI:  10.1080/02724634.2017.1301945

 

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