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Eucnemesaurus

Van Hoepen, 1920 yook-NEEM-ee-SOR-us /juːkˌniːmɪˈsɔːrəs/ Disputed

From Greek eu- (good/well) + kneme (tibia/shin) + sauros (lizard): 'good tibia lizard', referring to its robust tibiae.

227.3–201.4 million years ago Norian–Rhaetian, Late Triassic
Late Triassic stages

Eucnemesaurus is a basal sauropodomorph dinosaur genus usually considered to be a synonym of Euskelosaurus. Recent study by Yates (2007), however, indicates that it is valid and the same animal as putative "giant herrerasaurid" Aliwalia.

Diagnosis

  1. Tibia head proportionally much larger (longer and broader) than in all compared Plateosauridae and Anchisauridae, including Gryponyx, Plateosaurus, and Massospondylus
  2. Trochanter minor of femur situated nearly equidistant from medial and lateral sides, not near the medial side as in most Plateosauridae
  3. Anterior border of distal tibia end longer than posterior border, the reverse of Euskelesaurus Browni and Gresslyosaurus robustus
  4. Pubic neck section lacks ridges on lower surface present in Euskelesaurus; neck relatively short with no demarcation between anterior and medial surfaces
  5. Femur of practically solid structure with thick lamellar substantia compacta and only small central cavity, contrasting with hollow limb bones typical of Theropoda
  6. Trochanter quartus situated relatively closer to the proximal end of the femur than in Euskelesaurus Browni

Species (2)

Eucnemesaurus fortis Van Hoepen, 1920 Disputed

Type species

From Latin 'fortis' meaning 'strong', reflecting the robust nature of the described material.

Holotype
TM 119 , Ditsong National Museum of Natural History
Material
Proximal half of left femur, complete left tibia, proximal portion of left pubis, portions of dorsal and caudal vertebrae, and unidentified fragments.
Horizon
lower Elliot Formation, Norian–Rhaetian, Late Triassic , 227.3–201.4 million years ago
Locality
Farm Zonderhout, near Slabberts, Free State, South Africa

Eucnemesaurus entaxonis McPhee et al., 2015

From 'entaxonic', a foot in which the medial digits bear the main weight-resisting forces; alludes to the species' robust pes.

Holotype
BP/1/6234 , Evolutionary Studies Institute (formerly Bernard Price Institute for Palaeontological Research), University of the Witwatersrand
Material
Articulated posterior dorsal, sacral, and anterior caudal vertebrae; partial right ilium and pubic apron; left ischium; right femur; distal crus; and an almost complete right pes.
Horizon
lower Elliot Formation, Norian–Rhaetian, Late Triassic , 227.3–201.4 million years ago
Locality
Cannon Rock Farm, Eastern Cape, South Africa
Diagnosis
  1. Deep brevis fossa with relatively thin lateral and medial walls on the ventral surface of the postacetabular process of the ilium
  2. Sharp ventral keel on the centra of the proximal caudal vertebrae
  3. Femoral shaft beneath the fourth trochanter transversely elliptical in cross-section (subcircular in E. fortis)
  4. Posterior descending process of the distal tibia does not extend as far laterally as the anterior ascending process, leaving the latter visible in posterior view (the two processes are level with each other in E. fortis)
  5. Semi-stout pes in which the maximum proximal breadth of the first metatarsal is approximately 0.6 times its proximodistal length

Synonyms of the genus

Name Type Reason
Aliwalia junior subjective Tentatively treated as a junior synonym of Eucnemesaurus; very recent (2026) research suggests Aliwalia may be a distinct genus, pending broader confirmation.

References

  1. Van Hoepen, E. C. N. (1920). Contributions to the knowledge of the reptiles of the Karroo Formation. 6. Further dinosaurian material in the Transvaal Museum. Annals of the Transvaal Museum 7(2): 93-141. vanhoepen1920a
  2. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the body length and mass estimates.

    paul2024a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Sauropods. Princeton University Press.

    Source of the hip height estimate.

    jones2026b
  4. Yates, A. M. (2007). Solving a dinosaurian puzzle: the identity of Aliwalia rex Galton. Historical Biology 19(1): 93-123. doi:10.1080/08912960600866953

    Indicated Eucnemesaurus is valid and conspecific with the putative herrerasaurid Aliwalia.

    yates2007a
  5. McPhee, B. W.; Choiniere, J. N.; Yates, A. M.; Viglietti, P. A. (2015). A second species of Eucnemesaurus Van Hoepen, 1920 (Dinosauria, Sauropodomorpha): new information on the diversity and evolution of the sauropodomorph fauna of South Africa's lower Elliot Formation (latest Triassic). Journal of Vertebrate Paleontology 35(5): e980504. Informa UK Limited. doi:10.1080/02724634.2015.980504

    Places both species in the lower Elliot Formation.

    mcphee2015b