Article · Wikipedia archive · Last revised Jun 19, 2026

Ogmodirus

Ogmodirus is an extinct genus of plesiosaur found in the Cenomanian-Turonian Greenhorn Limestone of Kansas. The type species, Ogmodirus martini, was named by Samuel Wendell Williston and Roy Lee Moodie in 1913.

Last revised
Jun 19, 2026
Read time
≈ 2 min
Length
361 w
Citations
12
Source
Ogmodirus
Temporal range: Late Cretaceous,
Paddle bone of KUVP 441
Cervical series of KUVP 441
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Superorder: Sauropterygia
Order: Plesiosauria
Superfamily: Plesiosauroidea
Family: Elasmosauridae
Genus: Ogmodirus
Williston and Moodie, 1913
Species:
O. martini
Binomial name
Ogmodirus martini
Williston & Moodie, 1913

Ogmodirus is an extinct genus of plesiosaur found in the Cenomanian-Turonian (Late Cretaceous) Greenhorn Limestone of Kansas.12 The type species, Ogmodirus martini, was named by Samuel Wendell Williston and Roy Lee Moodie in 1913.2

Discovery and naming

The holotype, KUVP 441, consists of a pelvic girdle, limb elements, and more than fifty cervical (neck) vertebrae from a juvenile discovered in Cloud County, Kansas by C. Boyce in 1909.2 KUVP 441 was named as Ogmodirus martini by Williston & Moodie (1913)2 and the specific name was emended to martinii by Moodie (1916), but the original name takes precedence.3 The holotype was described in detail by Williston & Moodie (1917).3

A second species, Ogmodirus ischiadicus (based on specimen KUVP 434), was initially placed within its own genus, Thalassiosaurus,3 and has since been referred to Styxosaurus.4 It was placed in Ogmodirus by Williston & Moodie (1917).3

Classification

According to Welles (1962),5 Ogmodirus martini may be member of the Elasmosauridae, a group of marine animals related to Elasmosaurus, but the condition of the fossils discovered to date means the genus is dubious beyond Plesiosauria. Sepkoski (2002) assigned Ogmodirus to the Plesiosauria.6

See also

See also

References

References

  1. Ogmodirus martini from Oceans of Kansas
  2. Williston, S. W. and Moodie, R. L. (1913). New plesiosaurian genus from the Cretaceous of Nebraska. Bulletin of the Geological Society of America 24: 120-121.
  3. S. W. Williston and R. L. Moodie. (1917). Ogmodirus martinii, a new plesiosaur from the Cretaceous of Wyoming. The University of Kansas Science Bulletin 10(2):61-73
  4. S. W. Williston. (1903). North American plesiosaurs, part 1. Geological Series Field Museum of Natural History 3(1):1-77
  5. S. P. Welles. (1962). A new species of elasmosaur from the Aptian of Colombia and a review of the Cretaceous plesiosaurs. University of California Publications in Geological Sciences 44(1):1-96
  6. Sepkoski, J.J. (2002). A compendium of fossil marine animal genera. Bulletins of American Paleontology 363:1-560.