Genus: Macelognathus MARSH, 1884
Etymology: Greek, macel, "slaughter" and Greek, gnathus, "jaw".
= Macellognathus MARSH, 1884 (sic)
= Macelognathus MARSH, 1884 (sic)
= Marcellognathus MARSH, 1884 (sic)

Species: vagans MARSH, 1884
Etymology: Greek, vagans, "to wonder, to stroll."

Holotype: YPM 1415

Locality: Reeds YPM Quarry 9, (Mammal Quarry), T22N, R77W, Sec. 12, Como Bluff, Albany County, Wyoming.

Horizon: Brushy Basin Member, Morrison Formation.

Biostratigraphy: Zone 3.

Age: Upper Part, Comobluffian age, Kimmeridgian Stage, uppermost Malm Epoch, Late Jurassic.

Material: Symphyseal and anterior portions of left and right dentaries.

Macelognathus vagans (modified from Göhlich et. al. 2005).

Referred material:

GÖHLICH, CHIAPPE, CLARK & SUES, 2005

Locality: Fruita Paleontological Area, localities "Fruita General" and "Fruita Main" Quarry 4, Mesa County, Colorado.

Note: The locality LACM 4684 (LACM e.g., LACM 468/133772) is a general number for severial quarries within a portion of the FPA, combined as "Fruita General". LACM locality numgber 5572 refers to George Callison's Quarry 4 ("Fruita Main"), a site contained withint the area designated as locality LACM 4684.

Horizon: Brushy Basin Member, Morrison Formation.

Biostratigraphy: Zone 4.

Age: Upper Part, Comobluffian age, Tithonian Stage, Uppermost Malm Epoch, Late Jurassic.

Material:

LACM 5572/150148: A partial skull, left dentary, 2 dorsal vertebrae, a left ilium, the proximal half of the left femur and distal halves of both femora, the right tibia and the distal half of hte left tibia, the proximal and distal ends of the right fibula and the distal half of the left fibula, the left calcaneum, portions of metatarsals, and indeterminate fragments of bone.

LACM 4684/128271: A right femur, proximal halves of both tibae and the distal half of the right one, the distal half of the right fibula, the left metatarsal II and most of the left metatarsal III, the proximal half of the right metatarsal II, and the distal half of a metatarsal (Possibly metatarsal III).

LACM 4684/128272: A single left femur.

LACM 5572/150211: Proximal end of the right metatarsal III and both calcanea.

LACM 4684/133772: Portion of the right maxilla, both dentaries including the symphysial region, and a fragmentary posterior portion of the cranial roof.