Miragaia
Named for the village of Miragaia, in Lourinhã, Portugal, and the geological unit of the same name. The stem can also be read as Latin mira, wonderful, and Gaia, the Greek goddess of the Earth.
Miragaia is a genus of long-necked stegosaurid dinosaur. Its fossils have been found in Upper Jurassic rocks in Portugal (Lourinhã Formation, Sobral Unit) and possibly also Wyoming and Utah, United States (Morrison Formation), from which Costa (2026) refers isolated caudal spines and a cervical plate to Miragaia. Miragaia has the longest neck known for any stegosaurian, which included at least seventeen vertebrae. Some researchers consider this taxon to be a junior synonym of Dacentrurus.
Under dispute
The validity of Miragaia is contested. It was erected as a long-necked dacentrurine (Mateus and colleagues, 2009). Raven and Maidment (2017) re-erected the genus, and Costa and Mateus (2019) concluded from a second, more complete specimen that it is valid and distinct from Dacentrurus armatus. Sánchez-Fenollosa, Escaso and Cobos (2025) proposed it as a subjective junior synonym of D. armatus, following a suggestion by Cobos and colleagues (2010). Its position is disputed too: Mateus and colleagues (2009) and Costa and Mateus (2019) placed it in Dacentrurinae as sister to Dacentrurus, and the synonymy would also put it there, while Raven and Maidment (2017) recovered it as sister to Hesperosaurus, and Raven and colleagues (2023) as sister to Adratiklit, closer to Stegosaurus than to Dacentrurus in both cases. It is placed at Stegosauridae, the nearest clade all of these accept.
Diagnosis
- At least 17 cervical vertebrae, eight more than basal ornithischians and most other stegosaurs
- Mid-cervical neural spines with notch at base and anterior projection dorsal to it
- Mid and posterior cervical and anterior dorsal neural spines with transversely expanded apices
- Paired, slightly outwardly convex, triangular cervical dermal plates with notch and projection on anterodorsal margin
- Anterior tip of premaxilla drawn into a point
- Anterolateral rim of premaxilla projects ventrally
Species
Miragaia longicollum Mateus et al., 2009 Disputed
Type species
From Latin 'longus' meaning 'long' and 'collum' meaning 'neck', in reference to the exceptionally long neck of this stegosaur.
- Holotype
- ML 433 , Museu da Lourinhã
- Material
- Nearly complete anterior half of skeleton with partial cranium, 15 cervical vertebrae, two dorsal vertebrae, coracoids, scapulae, humeri, radii and ulnae, metacarpal, phalanges, rib fragments, chevron, dermal spine and 13 dermal plates.
- Horizon
- Praia Azul Member, Lourinhã Formation, Kimmeridgian–Tithonian, Late Jurassic , 154.8–143.1 million years ago
- Locality
- Miragaia, Lisbon, Portugal
References
- Mateus, O.; Maidment, S. C. R.; Christiansen, N. A. (2009). A new long-necked 'sauropod-mimic' stegosaur and the evolution of the plated dinosaurs. Proceedings of the Royal Society B: Biological Sciences 276: 1815-1821. doi:10.1098/rspb.2008.1909 mateus2009a
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Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.
Source of the body length and mass estimates.
paul2024a -
Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.
Source of the hip height estimate, and the appearance features.
jones2026a -
Sánchez-Fenollosa, S.; Cobos, A. (2025). New insights into the phylogeny and skull evolution of stegosaurian dinosaurs: an extraordinary cranium from the European Late Jurassic (Dinosauria: Stegosauria). Vertebrate Zoology 75: 165-189. doi:10.3897/vz.75.e146618
Follows the synonymy with Dacentrurus armatus, coding D. armatus partly from Miragaia material; recovers D. armatus in Dacentrurinae with Alcovasaurus, Kentrosaurus, Thyreosaurus and Adratiklit.
sánchez-fenollosa2025a -
Cobos, A.; Royo-Torres, R.; Luque, L.; Alcalá, L.; Mampel, L. (2010). An Iberian stegosaurs paradise: The Villar del Arzobispo Formation (Tithonian–Berriasian) in Teruel (Spain). Palaeogeography, Palaeoclimatology, Palaeoecology 293(1-2): 223-236. Elsevier BV. doi:10.1016/j.palaeo.2010.05.024
Suggests from the Teruel stegosaur material that Dacentrurus and Miragaia are synonymous.
cobos2010a -
Raven, T. J.; Maidment, S. C. R. (2017). A new phylogeny of Stegosauria (Dinosauria, Ornithischia). Palaeontology 60(3): 401-408. doi:10.1111/pala.12291
Recovers Miragaia as sister to Hesperosaurus and re-erects the genus.
raven2017a -
Costa, F.; Mateus, O. (2019). Dacentrurine stegosaurs (Dinosauria): A new specimen of Miragaia longicollum from the Late Jurassic of Portugal resolves taxonomical validity and shows the occurrence of the clade in North America. PLOS ONE 14(11): e0224263. Public Library of Science (PLoS). doi:10.1371/journal.pone.0224263
Describes a second specimen and concludes that Miragaia longicollum is valid and distinct from Dacentrurus armatus, within Dacentrurinae.
costa2019a -
Raven, T. J.; Barrett, P. M.; Joyce, C. B.; Maidment, S. C. R. (2023). The phylogenetic relationships and evolutionary history of the armoured dinosaurs (Ornithischia: Thyreophora). Journal of Systematic Palaeontology 21(1): 2205433. doi:10.1080/14772019.2023.2205433
In its preferred analysis recovers Miragaia as sister to Adratiklit, closer to Stegosaurus than to Dacentrurus.
raven2023a -
Sánchez-Fenollosa, S.; Escaso, F.; Cobos, A. (2024). A new specimen of Dacentrurus armatus Owen, 1875 (Ornithischia: Thyreophora) from the Upper Jurassic of Spain and its taxonomic relevance in the European stegosaurian diversity. Zoological Journal of the Linnean Society 203(3): zlae074. Oxford University Press (OUP). doi:10.1093/zoolinnean/zlae074
Proposes Miragaia longicollum as a subjective junior synonym of Dacentrurus armatus.
sánchez-fenollosa2024a -
Costa, F. (2026). Dacentrurine Stegosaurs in North America: New Occurrences from the Upper Jurassic of USA (Morrison Formation). Diversity 18(3): 143. MDPI AG. doi:10.3390/d18030143
Refers caudal spines from the Cleveland-Lloyd Quarry, Utah, to Miragaia sp. and a cervical plate to cf. Miragaia longicollum.
costa2026a