PBDB Taxon

Basic info	Taxonomic history	Classification	Included Taxa
Morphology	Ecology and taphonomy	External Literature Search	Age range and collections

Dyoplosaurus acutosquameus

Reptilia - Ankylosauridae

Taxonomy

Dyoplosaurus acutosquameus was named by Parks (1924). Its type specimen is ROM 784, a partial skeleton (fragmentary skull, complete caudal series of vertebrae including tail club, ribs, pelvis, hind limb including pes, osteoderms in situ), and it is a 3D body fossil. Its type locality is RTMP Quarry 2, Happy Jack Ferry, which is in a Campanian channel sandstone in the Dinosaur Park Formation of Canada.

It was synonymized subjectively with Euoplocephalus tutus by Coombs (1986), Carpenter (2001), Vickaryous et al. (2004), Ryan and Evans (2005), Currie (2005).

Year	Name and author
1924	Dyoplosaurus acutosquameus Parks p. 5 figs. Pl. 1-4
1927	Dyoplosaurus acutosquameus Huene p. 261
1930	Dioplosaurus acutosquameus Hay p. 236
1930	Dyoplosaurus acutosquameus Russell p. 146
1935	Dyoplosaurus acutosquameus Parks p. 194
1939	Dyoplosaurus acutosquameus Riabinin p. 25
1954	Dyoplosaurus acutosquameus Maleev
1956	Dyoplosaurus acutosquameus Maleev
1964	Dyoplosaurus acutosquameus Kuhn p. 46
1964	Dyoplosaurus acutosquameus Russell p. 13
1964	Dyoplosaurus acutosquameus Tatarinov p. 575
1965	Dyoplosaurus acutosquameous Simmons p. 70
1970	Dyoplosaurus acutosquameus Swinton p. 247
2000	Dyoplosaurus acutosquameus Ford p. 175
2009	Dyoplosaurus acutosquameus Arbour et al.
2011	Dyoplosaurus acutosquameus Burns and Sullivan p. 177
2011	Dyoplosaurus acutosquameus Carpenter et al. p. 5
2012	Dyoplosaurus acutosquameus Arbour et al. p. 55
2013	Dyoplosaurus acutosquameus Arbour and Currie p. 31
2013	Dyoplosaurus acutosquameus Kirkland et al. p. 7
2013	Dyoplosaurus acutosquameus Penkalski and Blows p. 180–181
2014	Dyoplosaurus acutosquameus Arbour et al. p. 2
2014	Dyoplosaurus acutosquameus Arbour et al. p. 633
2014	Dyoplosaurus acutosquameus Penkalski p. 617
2016	Dyoplosaurus acutosquameus Arbour and Currie p. 418
2017	Dyoplosaurus acutosquameus Arbour and Mallon p. 772
2018	Dyoplosaurus acutosquameus Penkalski p. 265

Reference	Diagnosis
V. M. Arbour and P. J. Currie 2013	Differs from Anodontosaurus lambei, Euoplocephalus tutus, and Scolosaurus cutleri in having anterolaterally-directed sacral ribs, in having triangular unguals in dorsal view, and in having a tail club knob that is longer than wide; differs from Scolosaurus cutleri in having a proportionately shorter postacetabular process of the ilium, and in having triangular osteoderms on the lateral sides of the anterior portion of the tail; differs from Ankylosaurus magniventris in having anteriorly-directed nares, and in lacking a continuous keel between the squamosal horn and supraorbitals.
V. M. Arbour and P. J. Currie 2016	Differs from Anodontosaurus lambei, Euoplocephalus tutus and Scolosaurus cutleri in having anterolaterally directed sacral ribs, in having triangular unguals in dorsal view and in having a tail club knob that is longer than wide; differs from Scolosaurus cutleri in having a proportionately shorter postacetabular process of the ilium, and in having triangular osteoderms on the lateral sides of the anterior portion of the tail.
P. Penkalski 2018	Moderate-sized (5 m) euoplocephalin with two sacrocaudals and a variably fused cd 1 (sc3); overall synsacral count 4-3-2; caudal neural spines blade-like and backswept; 90° angle between proximal caudal zygapophyseal surfaces; femur robust, with distinct head; pedal unguals triangular; small, elongate tail club with lateral keels. Differs from E. tutus in having poorly defined cranial scales in frontal region, a centrally domed skull roof in rostral view, confluent, rounded supraorbital bosses, seven synsacrals not ncluding sacrocaudals, moderately divergent ilia (<25°) and highly rugose, perforate armour.