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Anningasaura, new plesiosaur from UK



From: Ben Creisler
bcreisler@gmail.com


In the new issue of JVP:

Peggy Vincent & Roger B. J. Benson  (2012)
Anningasaura, a basal plesiosaurian (Reptilia, Plesiosauria) from the
Lower Jurassic of Lyme Regis, United Kingdom.
Journal of Vertebrate Paleontology 32(5): 1049-1063
DOI:10.1080/02724634.2012.686467
http://www.tandfonline.com/doi/abs/10.1080/02724634.2012.686467



The plesiosaur specimen NHMUK OR49202, from the Lias Group of Lyme
Regis, consists of a complete skull, palate, and mandible, with eight
associated cervical vertebrae, including the atlas-axis complex. This
juvenile plesiosaur specimen was originally referred to ‘Plesiosaurus’
macrocephalus. However, reexamination indicates that it does not
belong to Plesiosaurus and comparison with the type specimen of
‘Plesiosaurus’ macrocephalus (NHMUK OR1336) suggests that it is
taxonomically distinct. Therefore, NHMUK OR49202 is made the holotype
of a new genus and species: Anningasaura lymense. The specimen
possesses plesiomorphic characters, including premaxillae that do not
separate the frontals on the midline, narrow cranioquadrate passages,
lack of a constricting groove around the occipital condyle, and
several autapomorphies not observed in other plesiosaurian taxa:
posteromedial processes of the premaxillae (or possible anterior
portion of the frontal) forming a dorsoventrally thick, mediolaterally
expanded platform; supplementary foramen penetrating the parietal
sagittal crest; absence of a pterygoid-vomerine contact; absence of a
contact between the pterygoids in palatal aspect; cultriform process
of the parasphenoid wider mediolaterally than the combined posterior
interpterygoid vacuities; and two closely spaced foramina in the
lateral surface of the exoccipital. Anningasaura lymense is a
plesiomorphic Early Jurassic taxon, and provides anatomical data that
clarify the early evolutionary history of Plesiosauria.


NOTE: I have not read the paper yet but the species name "lymense"
looks like a Latin neuter form even though the generic name
"Anningasaura" is clearly feminine, making "lymensis" the correct
spelling for "from Lyme" as an adjective. I'll download it and check
to see if some other meaning was meant--but at first glance it appears
to be another case of garbled Latin.