Genus: Apatosaurus MARSH, 1877
Etymology: Greek, apatao, “deceive” and Greek, sauros, “lizard”: Deceptive lizard. Because the caudal vertebrae were first thought to belong to a mosasaur then found out it really belonged to a sauropod.
= Apatosanrus YADAGIRI, 1988 (sic)
= Apatosausus DONG, 1979 (sic)
= Apotosaurus SAUVAGE, 1883 (sic)

Species: ajax MARSH, 1877
Etymology: In honor of a Greek hero Ajax and legendary king of Salamis who plays an important role in Homer's Iliad.
= Atlantosaurus ajax (MARSH, 1877) STEEL, 1970

Holotype: YPM 1860

Locality: Lakes' YPM Quarry 10, Jefferson County, Colorado.

Horizon: Member? Morrison Formation.

Biostratigraphy: Zone?

Age: Age?, Stage?, Malm Epoch, Late Jurassic.

Material: Fragmentary skeleton, with braincase, both quadrates, cervicals 12 to 15, 5 pairs and 2 single disarticulated cervical ribs, dorsals 1 to 4, and 6 to 10, all 5 sacrals, 18 caudals, sevral ribs, 6 chevrons, right and fragment of the left scapula, right coracoid, right ulna, right and fragmentary left ilia, left pubis, right ischium, fragment of the left femur, left tibia, and left fibula of a juvenile.
Note: Gastroliths were found? CANON, 1906.

Referred martial:

= Apatosaurus cf ajax BIRKEMEIER & SWOR, 2007

Locality: Warm Springs Ranch, Thermopolis area, Hot Springs County, Wyoming.

Horizon: ?Member, Morrison Formation.

Biostratigraphy: ?

Age: ?Late Jurassic.

Material:

Number: Not given: Fragmenary skull, assorted cervical, dorsal and caudal vertebrae, dorsal ribs, sternal ribs and limb material.

McINTOSH, 1995

Locality: ?

Horizon: Member? Morrison Formation.

Biostratigraphy: Zone?

Age: Age?, Stage?, Malm Epoch, Late Jurassic.

Material:

YPM 4676: Scapula and forelimb.

 

OSTROM & McINTOSH, 1966

Locality: Lake’s YPM Quarry 8, T4S, R70W, Sec. 26, Como Bluff, Albany County, Wyoming.

Horizon: Member? Morrison Formation.

Biostratigraphy: Zone?

Age: Age?, Stage?, Malm Epoch, Late Jurassic.

Material:

Number: Not given:

 

TURNER & PETERSON, 1999

Locality: Lake’s quarries, 1, 5, 8, Jefferson County, Colorado.

Horizon: Brushy Basin Member, Morrison Formation.

Biostratigraphy: Zone 3.

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

Material:

Number: Not given:

 

Locality: Lake’s quarry 10-L, Jefferson County, Colorado.

Horizon: Brushy Basin Member, Morrison Formation.

Biostratigraphy: Zone 3.

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

Material:

Number: Not given:

 

Locality: Lake’s quarry 10-U, Jefferson County, Colorado.

Horizon: Brushy Basin Member, Morrison Formation.

Biostratigraphy: Zone 3.

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

Material:

Number: Not given:

 

TANIMOTO, ATSUSHI, TAKATA & FUKIMOTO, 1997, TOMIDA, KATSURA, AZUMA, & KAMEI, 2001, UPCHURCH, TOMIDA & BARRETT, 2005

Locality: BS (Besides Sauropod) Quarry, Thermopolis area, Hot Springs County, Wyoming.

Horizon: Brushy Basin Member, Morrison Formation.

Biostratigraphy: Zone 3.

Age: Comobluffian age, Kimmeridgian Stage, Uppermost Malm Epoch, Late Jurassic.

Material:

NSM-PV 20375: Nearly complete skeleton.

IKEJIRI, WATKINS & GRAY, 2006

WDC:S-118 = BS-425: Distal caudal vertebra.

WDC:S-201: Distal caudal ertebra.

WDC:BS-713, 740: Isolated teeth.

 

WHITE, 1958

Locality: Bone Cabin Quarry, 8 miles north of Como, Medicine Bow Anticline (also called Flat top Anticline), Albany County, Wyoming.

Horizon: Salt Wash Member, Morrison Formation.

Biostratigraphy: Zone 2.

Age: Comobluffian age, Kimmeridgian Stage, Uppermost Malm Epoch, Late Jurassic.

Material:

AMNH 673: Occiput, frontal region and braincase.

 

Locality: Bone Cabin Quarry East (Eastward extension of old Bone Cabin Quarry), 8 miles north of Como, Medicine Bow Anticline (also called Flat top Anticline), Albany County, Wyoming.

Horizon: Salt Wash Member, Morrison Formation.

Biostratigraphy: Zone 2.

Age: Comobluffian age, Kimmeridgian Stage, Uppermost Malm Epoch, Late Jurassic.

Material:

Number: Not given:

 

= Atlantosaurus immanis MARSH, 1878
Etymology: Latin, immanis, "immense."

Holotype: YPM 1840

Locality: Lakes' YPM Quarry 10, Jefferson County, Colorado.

Horizon: Member? Morrison Formation.

Biostratigraphy: Zone?

Age: Age?, Stage?, Malm Epoch, Late Jurassic.

Material: Fragmentary anterior cervical, cervicals 9, 10, 13, 115, dorsals 1, 3, 5, 8 and fragmentary 6, 7, 9, 10, sacral 1, several caudals, several ribs, 3 chevrons, both fragmentary coracoids, left pubis, and a fragment of the right one, both ischia, upper and lower segments of the left femur, upper halfs of the right tibia and left fibula, and a pedal phalanx.
Note: Gastroliths were found? CANON, 1906.

A) Cervical vertebra; B) Dorsal vertebra; C) Pubis and ischium; D) Femur.

Referred material:

LYDEKKER, 1888

BMNH R338: Cast of a left femur.

= Apatosaurus laticollis MARSH, 1879
Etymology: Latin, latus, “wide” and Latin,‎ collum, “neck, throat, stem.”
= Atlantosaurus laticollis (MARSH, 1879) STEEL, 1970

Holotype: YPM 1861

Locality: Lakes' YPM Quarry 10, Jefferson County, Colorado.

Horizon: Member? Morrison Formation.

Biostratigraphy: Zone?

Age: Age?, Stage?, Malm Epoch, Late Jurassic.

Material: Fragmentary 13? cervical vertebra.

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