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Dacentrurus armatus

Osteichthyes - Stegosauridae

Taxonomy
Omosaurus armatus was named by Marsh (1877). Its type specimen is BMNH 46013, a set of postcrania, and it is a 3D body fossil. Its type locality is Swindon Brick and Tile Company brick pit, which is in a Kimmeridgian marine claystone in the Kimmeridge Clay Formation of the United Kingdom. It is the type species of Dacentrurus.

It was recombined as Stegosaurus armatus by Dollo (1889), Gadow (1901); it was considered a nomen dubium by Maidment (2010); it was recombined as Dacentrurus armatus by Lucas (1902), Hennig (1915), Delair (1960), Delair (1973), Thulborn (1975), Galton (1982), Galton (1983), Galton (1985), Galton (1990), Galton (1991), Olshevsky and Ford (1993), Galton (1994), Casanovas-Cladellas et al. (1995), Casanovas-Cladellas et al. (1995), Sanz (2000), Pereda Suberbiola and Galton (2001), Carpenter et al. (2001), Blows (2001), Ruiz-Omeñaca and Canudo (2003), Pereda Suberbiola et al. (2003), Pereda Suberbiola et al. (2005), Mateus (2006), Escaso et al. (2006), Escaso et al. (2007), Maidment et al. (2008), Suñer et al. (2008), Naish and Martill (2008), García-Ramos et al. (2008), Cobos et al. (2008), Butler et al. (2008), Ortega et al. (2009), Pereda Suberbiola et al. (2009), Company et al. (2010), Mateus and Milàn (2010), Barrett and Maidment (2011), Gaete et al. (2011), Pascual et al. (2012), Cobos and Gascó (2013), Cobos et al. (2014), Ulansky (2014), Ulansky (2014), Saitta (2015), Borinder et al. (2016), Galton and Carpenter (2016), Costa and Mateus (2019), Mocho et al. (2019), Maidment et al. (2020), Breeden et al. (2021), Sánchez-Fenollosa et al. (2024), Sánchez-Fenollosa and Cobos (2025).

Synonyms
Synonymy list
YearName and author
1875Omosaurus armatus Owen p. 45
1876Omosaurus armatus Hudleston p. 543
1876Omosaurus armatus Sauvage p. 439
1877Omosaurus armatus Marsh p. 435
1877Omosaurus armatus Owen p. 95
1878Omosaurus armatus Cope p. 57
1880Omosaurus armatus Sauvage p. 523
1882Omosaurus armatus Quenstedt p. 188
1887Osmosaurus armatus Hulke p. 376
1887Omosaurus armatus Hulke p. 700
1888Omosaurus armatus Lydekker p. 177
1889Stegosaurus armatus Dollo p. 680
1890Omosaurus armatus Woodward and Sherborn p. 253
1890Omosaurus armatus Zittel p. 748
1893Omosaurus armatus Seeley p. 54
1893Omosaurus armatus Winkler p. 104
1896Omosaurus armatus Depéret p. 185
1896Omosaurus armatus Mansel-Pleydell p. 119
1896Omosaurus armatus Marsh p. 196
1901Stegosaurus armatus Gadow p. 425
1901Omosaurus armatus Nopcsa p. 214
1902Dacentrurus armatus Lucas p. 435
1902Omosaurus armatus Sauvage p. 408
1910Omosaurus armatus Lull p. 377
1911Omosaurus armatus Nopcsa p. 23
1915Dacentrurus armatus Hennig p. 11
1924Omosaurus armatus Lull p. 242
1939Omosaurus armatus Kuhn p. 113
1951Omosaurus armatus Lapparent and Zbyszewski p. 1127
1957Omosaurus armatus Lapparent and Zbyszewski p. 48
1960Dacentrurus armatus Delair p. 87
1970Omosaurus armatus Swinton p. 241
1973Dacentrurus armatus Delair p. 5
1975Dacentrurus armatus Thulborn p. 89
1982Dacentrurus armatus Galton p. 145
1983Dacentrurus armatus Galton p. 11
1985Dacentrurus armatus Galton p. 213 figs. 2-14
1990Dacentrurus armatus Galton
1991Dacentrurus armatus Galton pp. 317-318
1993Dacentrurus armatus Olshevsky and Ford
1994Dacentrurus armatus Galton p. 257
1995Dacentrurus armatus Casanovas-Cladellas et al. p. 269
2000Dacentrurus armatus Sanz p. 292
2001Dacentrurus armatus Blows pp. 138-139
2001Dacentrurus armatus Carpenter et al. p. 73
2001Dacentrurus armatus Pereda Suberbiola and Galton p. 150
2003Dacentrurus armatus Pereda Suberbiola et al. p. 144
2003Dacentrurus armatus Ruiz-Omeñaca and Canudo p. 282
2005Dacentrurus armatus Pereda Suberbiola et al. p. 176
2006Dacentrurus armatus Escaso et al. p. 79
2006Dacentrurus armatus Mateus p. 231
2007Dacentrurus armatus Escaso et al. p. 158
2008Dacentrurus armatus Butler et al. p. 7
2008Dacentrurus armatus Cobos et al. p. 90
2008Dacentrurus armatus García-Ramos et al. p. 33
2008Dacentrurus armatus Maidment et al. p. 6
2008Dacentrurus armatus Naish and Martill p. 616
2008Dacentrurus armatus Suñer et al. p. 400
2009Miragaia longicollum Araújo et al. p. 3 fig. 2
2009Miragaia longicollum Mateus p. 144A
2009Miragaia longicollum Mateus et al.
2009Dacentrurus armatus Ortega et al. p. 48
2009Miragaia longicollum Ortega et al. p. 49
2009Dacentrurus armatus Pereda Suberbiola et al. p. 13
2010Dacentrurus armatus Company et al. p. 248
2010Miragaia longicollum Galton p. 190
2010Dacentrurus armatus Mateus and Milàn p. 253
2011Dacentrurus armatus Barrett and Maidment p. 404
2011Dacentrurus armatus Gaete et al. p. 179
2012Dacentrurus armatus Pascual et al. p. 306
2013Dacentrurus armatus Cobos and Gascó p. 18
2013Miragaia longicollum Ruiz-Omeñaca et al. p. 37
2014Dacentrurus armatus Cobos et al. p. 48
2014Dacentrurus armatus Ulansky p. 7
2014Miragaia longicollum Ulansky p. 7
2014Dacentrurus armatus Ulansky p. 13
2014Miragaia longicollum Ulansky p. 16
2015Dacentrurus armatus Saitta p. 2
2016Dacentrurus armatus Borinder et al. p. 64
2016Dacentrurus armatus Galton and Carpenter p. 200
2019Dacentrurus armatus Costa and Mateus p. 19
2019Miragaia longicollum Costa and Mateus p. 20
2019Dacentrurus armatus Mocho et al. p. 2
2020Dacentrurus armatus Maidment et al. p. 91
2020Miragaia longicollum Maidment et al. p. 92
2021Dacentrurus armatus Breeden et al. p. 21
2023Miragaia longicollum Manitkoon et al. p. 3
2024Miragaia longicollum Burigo and Mateus p. 4
2024Dacentrurus armatus Sánchez-Fenollosa et al. p. 2
2025Dacentrurus armatus Sánchez-Fenollosa and Cobos p. 170

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RankNameAuthor
kingdomAnimalia()
—Bilateria
—EubilateriaAx 1987
—Deuterostomia
phylumChordataHaeckel 1874
subphylumVertebrata
superclassGnathostomata
classOsteichthyes
subclassSarcopterygii()
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
—Tetrapoda
—Reptiliomorpha
—Anthracosauria
subclassAmphibiosauriaKuhn 1967
—Cotylosauria()
—Amniota
—Sauropsida
classReptilia
subclassEureptilia()
—Romeriida
—Diapsida()
—Archosauromorpha(Huene 1946)
RankNameAuthor
—Crocopoda
—ArchosauriformesGauthier 1986
—Eucrocopoda
—Archosauria()
informalAvemetatarsalia
—Ornithodira
—Dinosauromorpha
—Dinosauriformes
—Dinosauria()
—Ornithischia()
—ParapredentataNorman 2022
—SaphornithischiaMadzia et al. 2001
—PrionodontiaOwen 1874
—Genasauria
—Thyreophora()
superfamilyThyreophoroidea()
—Eurypoda
—Stegosauria()
familyStegosauridae
—Neostegosauria
subfamilyDacentrurinae()
genusDacentrurus
speciesarmatus()

If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

†Dacentrurus armatus Marsh 1877
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Invalid names: Miragaia longicollum Mateus et al. 2009 [synonym]
Diagnosis
ReferenceDiagnosis
P. M. Galton 1991Twelve cervical vertebrae, centra of posterior third of neck and of the dorsal series are massive so the maximum transverse width is greater than the maximum length; in dorsal vertebrae from posterior two-thirds of series, the solid pedicel-like region is short and the minimum angle between each transverse process and the neural splne is 55°. Sacrum consists of seven coossified centra with two dorsosacral vertebrae anteriorly. Centra of anterior caudal vertebrae are massive and the short neural splnes have massive rounded tops. Anterior process of ilium is short and broadens anteriorly; distal part of ischium tapers and is straight in lateral view. Ratio of maximum lengths of humerus to radius is 1 : 0.69, of humerus to ulna is 1 : 0.79, of femur to humerus is 1 : 0.68, and of femur to ilium is 1: 0.85. Dermal armor includes at least small plates with a thick base, two pair of stocky spines with an expanded base, and four pairs of long caudal spines with a small base (modified from GALTON, 1985).
S. C. R. Maidment et al. 2008Differs from all other stegosaurs in possessing dorsal vertebral centra that are wider transversely than they are long anteroposteriorly. The dorsal surface ofthe distal ischial shaft is straight,
O. Mateus et al. 2009 (Miragaia longicollum)Differs from other stegosaurs in the presence of the following autapomorphies: (i) anterior tip of the premaxilla is drawn into a point, (ii) anterolateral rim of the premaxilla projects ventrally, (iii) at least 17 cervical vertebrae, (iv) mid-cervical neural spines possess a notch at their base with an anterior projection dorsal to it, (v) mid and posterior cervical and anterior dorsal neural spines with transversely expanded apices, and (vi) paired, slightly outwardly convex, triangular cervical dermal plates with a notch and projection on the anterodorsal margin.
F. Costa and O. Mateus 2019Suggested revised diagnosis, modified from [9] with additional characters named herein. Differs from all other stegosaurs in possessing: (i) straight dorsal surface of the distal ischial shaft; (ii) anterior end of the prepubis expanded ventrally; (iii) apex of cervical neural spines expanded posteriorly; (iv) cervical transverse processes borne at mid height of the prezygapophyses.
F. Costa and O. Mateus 2019 (Miragaia longicollum)Modified from [22]: Differs from other stegosaurs in the presence of the following autapomorphies: (i) anterior tip of the premaxilla is drawn into a point; (ii) anterolateral rim of the premaxilla projects ventrally; (iii) at least 17 cervical vertebrae; (iv) spinopostzygapophyseal lamina extending anteriorly from the epipophyses, accompanied medially by a pair of lower parallel ridges, passing laterally on the neural spine and culminating on an anterior projection on the base of the neural spine with a notch ventral to it (revised autapomorphy from [22]); (v) mid and posterior cervical and anterior dorsal neural spines with trans- versely expanded apices; (vi) paired, slightly inwardly convex, triangular cervical dermal plates with a notch and projection on the posterodorsal margin (revised autapomorphy from [22]); (vii) cervical neural spines are positioned over the anterior half of the centrum and become progressively more anteriorly positioned passing posteriorly on the cervical series; (viii) cervical transverse processes more than half the axial length of the centrum in all but the anteriormost cervical vertebrae; (ix) outline in lateral view of cervical prezygapophyses round posteriorly and straight anteriorly with an anterodorsal notch; (x) closed proximodorsal canal on the ribs of the first caudal vertebra; (xi) progressively more posteriorly inclined neural spines of anterior caudal vertebrae, inclined at less than 45° to the horizontal between Cd8 and Cd11; (xii) neural spine reduced to one fifth the height and width from the 10th to the 12th caudal vertebra, vestigial further posteriorly in the vertebral series; (xiii) presence of longitudinal cord-like ridges in the femur shaft, two posteriorly and one anterolaterally positioned, with distal bifurcation.
S. Sánchez-Fenollosa and A. Cobos 2025D. armatus possesses the following autapomorphies (modified from Sánchez-Fenollosa et al. 2025): A premaxilla with (1) an anterior tip that drawn into a point; and (2) an anterolateral margin ventrally projected; a supraoccipital with (3) a posteroventrally orientation with an angle greater than 90° with the dorsal plane of the skull roof (new); a cervical series with (4) at least 17 cervical vertebrae; and (5) at least anterior and mid cervical ribs fused to the vertebrae; cervical vertebrae with (6) two spinopostzygapophyseal laminae that extend anterolaterally from the top of the postzygapophyses to both sides of the base of the neural spine and culminate on its anterior margin; mid and posterior cervical vertebrae with (7) neural spines positioned in the anterior half of the centrum; anterior caudal vertebrae with (8) short neural spines and expanded and rounded apices; an ilium with (9) a wide and short preacetabular process; and (10) a broad base of
the preacetabular process and a smooth curvature between the anterior margin of the sacral yoke and the dorsal margin of the preacetabular process; and a pubis with (11) a dorsoventrally expanded anterior end of the prepubis.