Meroktenos
| Meroktenos Temporal range: Late Triassic, 216.5–201 Ma | |
|---|---|
 | |
| Right femur | |
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Order: | Saurischia |
| Clade: | Eusaurischia |
| Suborder: | †Sauropodomorpha |
| Genus: | †Meroktenos Peyre de Fabrègues & Allain, 2016 |
| Type species | |
| Meroktenos thabanensis (Gauffre, 1993) | |
Meroktenos is a genus of sauropodomorph dinosaur that lived during the Late Triassic of Lesotho.
Discovery and naming
In 1959, François Ellenberger, Paul Ellenberger, Jean Fabre and Leonard Ginsburg discovered the type specimen, a femur and other assorted bones, south of the village Thabana Morena. In 1962 these were addressed in an article by D. Costedoat. The exact location the bones were recovered remains unknown.
In 1993, François-Xavier Gaufre assigned the remains to a second species of Melanorosaurus: Melanorosaurus thabanensis. The description was provisional, and in 1997 the fossil was described in more detail in a publication by Jacques van Heerden and Peter Malcolm Galton. The specific name refers to the site Thabana-Morena in Lesotho.
In 2016, M.thabanensis was appointed to the separate genus Meroktenos by Claire Peyre of Fàbregues and Ronan Allain. The genus name is a combination of ancient Greek μηρός, meros ("thigh") and κτῆνος, ktènos ("beast").
The holotype, MNHN.F.LES 16, consists of a right thigh (MNHN.F.LES16c), a portion of the right ilia, with a piece of vertebral arch (MNHN.F.LES16a); a left pubis (MNHN.F.LES16b); and a second right metatarsal (MNHN.F.LES16d) associated with the skeleton. In 2016, a new specimen, MNHN.F.LES351, was discovered; consisting of a cervical vertebra, a left ulna and a radius.
Description
Meroktenos has a femur length of around 48 centimeters, suggesting a height of about four meters. In 2016, it was given a revised list of distinctive features; the blade height of the ilium, measured from the highest point of antitrochanter to the upper edge of the sheet is 60% of the total height of the ilium and including appendices.
The backsheet of the ilium is roughly triangular in side view. The femur is very compact with a robusticiteitsindex, length divided by the circumference of shaft 2.09. The femur has a straight axis in both side and front views. The femoral shaft is substantially wider than it is wide across in side view, with a ratio of 1.58. In the femoral shaft, located at the rear of a room, the trochanter oriented obliquely extending from the top down and in and out.
Phylogeny
Mertens put Meroktenos in the suborder Sauropodomorpha. According to an cladistic analysis, the position of Meroktenos was in a polytomy with Blikanasaurus and Aardonyx in the family tree and a different with Melanorosaurus and Antetonitrus . Across the width of the femur, the eccentricity, is remarkably high for such a small animal. These proportions were known previously only from Sauropoda which were explained as an adaptation to a very high absolute weight. Because the holotype probably not a young animal and not the giant will become the property must have had a different function.
Literature
- Costedoat D., 1962, Etude de quelques reptiles fossiles thesis, University of Paris
- Gauffre FX 1993, "The latest Melanorosauridae (Saurischia, Prosauropoda) Jurassic of Lesotho, with comments on the prosauropod phylogeny," Neues Jahrbuch für Geologie und Paläontologie '11' '. 648 -654
- Gauffre. F-X 1996 phylogeny prosauropodes et d'étude du Trias dinosaurs one prosauropode Superior d'Afrique australe Dissertation, National Museum of Natural History
- Peyre de Fabrègues, C; Allain, R (2016). "New material and revision of Melanorosaurus thabanensis, a basal sauropodomorph from the Upper Triassic of Lesotho". PeerJ 4: e1639. doi:10.7717/peerj.1639. PMID 26855874.