Enigmacursor
From Latin enigma (puzzle/riddle) + cursor (runner): 'puzzle runner', referring to the taxonomic confusion surrounding Morrison Formation neornithischians.
Late Jurassic stages
Enigmacursor is an extinct genus of neornithischian dinosaur from the Late Jurassic Morrison Formation of Colorado, United States. The type species is Enigmacursor mollyborthwickae.
Diagnosis
- Posterior articular facets offset ventrally relative to anterior articular facets on proximal dorsal vertebrae (potential autapomorphy)
- Absence of a supracetabular crest on the ilium
- Femoral head separated from the greater trochanter by a trochanteric fossa; apex of anterior trochanter situated level with the ventral margin of the femoral head
- Absence of a ligament sulcus on the posterior surface of the femoral head
- Ventral surface of fourth trochanter straight or slightly convex in medial or posterior view
- Medially directed, hook-like posterior condyle of the proximal end of the tibia
Species
Enigmacursor mollyborthwickae Maidment & Barrett, 2025
Type species
Named for Molly Borthwick, who donated the funds for the acquisition of the holotype specimen by the Natural History Museum, London.
- Holotype
- NHMUK PV R 39000 , Natural History Museum
- Material
- Partial skeleton including three teeth, three cervical, 11 dorsal, two dorsosacral and five caudal vertebrae, 10 dorsal ribs, five chevrons, right sternum, both scapulae, both humeri, both radii, both ulnae, three metacarpals, left ilium, right ischium, right pubis, both femora, both tibiae, both fibulae, right astragalus and both pedes.
- Horizon
- Morrison Formation, Kimmeridgian–Tithonian, Late Jurassic , 154.8–143.1 million years ago
- Locality
- Skull Creek Estates, Colorado, United States
References
- Maidment, S. C. R.; Barrett, P. M. (2025). Enigmacursor mollyborthwickae, a neornithischian dinosaur from the Upper Jurassic Morrison Formation of the western USA. Royal Society Open Science 12(6). The Royal Society. doi:10.1098/rsos.242195 maidment2025a