Genus: Achelousaurus SAMPSON, 1995
= Achelousaurus SAMPSON, 1993 (nomen nudum)
Etymology: Achelous (Greek Mythological figure, River-God of Aitolia [Aetolia]) and sauros (lizard, latinized
Greek). Achelous is a river god from Greek mythology who was able to transform
himself into any shape. In order to combat Heracles (Hercules), Achelous took
the form of a bull, but Hercules won the battle after removing one of Achelous’horns.
The allusion refers to the apparently transitional morphology of the animal
as well as to the ontogenetic and phylogenetic loss of horns characteristic
of the
genus.
= Taxon C* HORNER, VARRICCHIO & GOODWIN,
1992
Species: horneri SAMPSON, 1995
= Achelousaurus horneri SAMPSON, 1993 (nomen nudum)
Etymology: In honor of John R. Horner, in honor of his innovative research
on the dinosaurs of the Two Medicine Formation, Montana.
Holotype: MOR 485
Locality: Landslide Butte Field Area, approximately 40 km northwest of Cut Bank, Glacier County, Montana.
Horizon: Two Medicine Formation.
Biostratigraphy:
Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.
Material: Partial skull including nasal boss, supraorbital bosses and parietal. Left and right maxillae, nasal, left and right lachrymal, prefrontal, postorbital, left and right squamosal, parietal, quadrate, left and right palatine, braincase, basioccipital.
Referred material:
Locality: Black Tail Creek, Glacier County, Montana.
Horizon: Two Medicine Formation.
Biostratigraphy:
Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.
Material:
MOR 591: A well preserved sub-adult, including partial skull and partial postcranium (mostly complete vertebral column, complete pelvis and sacrum, one femur. Rostrum, premaxilla, maxilla, nasal, lachrymal, prefrontal, palpebral, postorbital, jugal, quadratojugal, squamosal, parietal, left and right quadrate, pterygoid, palatine, ectopterygoid, vomer, predentary, dentary, splenial, surangular, angular, coronoid, intercoronoid, prearticular, and articular.
MOR 571: A partial skull with associated vertebrae and ribs. Parietal, left and right surangular, and articular.
Note: Found at a nearby locality.