Genus: Miragaia MATEUS, MAIDMENT & CHRISTIANSEN, 2009
Etymology: Miragaia, after the locality and geological unit of the same name.
= Alcovasaurus GALTON, & CARPENTER, 2016
Etymology: In reference to Alcova, Natrona County, Wyoming, where the specimen was found, and Greek, sauros, "lizard."
= Natronasaurus ULANSKY, 2014a (nomen nudum)
Etymology: In reference to Natrona County, Wyoming, where it was found and Greek, sauros, "lizard."

Species: longispinus (GILMORE, 1914) COSTA & MATEUS, 2019
Etymology: Latin, longus, 'long', and Latin, spina, "spine, spike, needle."
= Stegosaurus longispinus GILMORE, 1914
= Natronasaurus longispinus (GILMORE, 1914) ULANSKY, 2014a (nomen nudum)
= Alcovasaurus longispinus (GILMORE, 1914) GALTON, & CARPENTER, 2016

Holotype: (UW 20503) D54

Locality: About 1 1/2 miles east of Alcova, Natrona County, Wyoming.

Horizon: Member? Morrison Formation.

Biostratigraphy: Zone?

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

Material: 42 vertebrae, fragmentary sacrum, 2 ischia, portion of one pubis, right femur, several ribs and 4 dermal tail spines.
Note: Lost?
Note: USNM has casts of the tail spines.

After Gilmore, 2014.

Referred material:

Locality: Griffin Ranch, ner Bone Cabin Quarry, Como Bluff, Albany County, Wyoming.

Horizon: Member? Morrison Formation.

Biostratigraphy: Zone?

Age: Age? Stage? Epoch? Late Jurassic.

Material:

DMNH 33431: Base of a huge spike.

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Species: longicollum MATEUS, MAIDMENT & CHRISTIANSEN, 2009
Etymology: Latin, longus, 'long', and Latin, collum, 'neck'; in reference to its long neck. In addition, the stem Mira-can be read as the feminine form of Latin mirus, meaning wonderful, while Gaia is the Greek goddess of the Earth, so the name also means 'Wonderful goddess of the Earth'.

Holotype: ML 433

Locality: Close to the Miragaia at the municipality of Lourinha, Estremadura Province, West coast of Portugal.

Horizon: Miragaia Unit, Sobral Formation, Lourinha Group.

Biostratigraphy:

Age: Upper Kimmeridgian-Lower Tithonian Stage, Middle-Upper Malm Epoch, Late Jurassic.

Material: Nearly complete anterior half of a skeleton, right premaxilla, partial left maxilla, left nasal, right postorbital, right and left angulars, 15 cervical vertebrae (atlas and axis absent) with associated ribs, 2 dorsal vertebrae, both coracoids, scapulae, humeri, radii and ulnae, 1 metacarpal, 3 phalanges, 12 rib fragments, 1 cheveron, 1 dermal spine and 13 plates.

Referred material:

ML 433-A: 2 dorsal centra, 3 dorsal neural arches a right pubis, and left ilium of a juvenile.

Note: May belong to a different genus.