Dracopelta zbyszewskii, the Portuguese Dragon Knight

I feel that even though the blog is named Dracopelta, there was no proper explanation or introduction as to why I chose this name. So, this post is exactly about this enigmatic taxon and the namesake of the blog.

Dracopelta zbyszewskii is a poorly known taxon of ankylosaur from the Late Jurassic of Portugal. It was named in 1980 by Peter Galton and its genus name comes from the Latin “draco” for dragon and from the Greek “peltē” for small shield. The exact positioning of D. zbyszewskii within Ankylosauria is problematic, with authors considering it either an nodosaurid (Galton, 1980, 1983; Coombs & Maryańska, 1990), a polacanthid incertae sedis (Pereda-Superbiola et al., 2005, and reference therein), Ankylosauria incertae sedis (Pereda-Superbiola et al., 2005) or even nomen dubium (Carpenter, 2001).

It was discovered in the 60’s during the construction of a road near the coastal village of Ribamar, in the municipality of Torres Vedras, Portugal. Georges Zbyszewski, a prominent French geologist and paleontologist who worked for decades in the Geological Services of Portugal and in honor of whom the species was named, was responsible for the excavation and preparation of the specimen in Lisbon (Pereda-Superbiola et al., 2005). Only in 1980 was the specimen described for the first time, by Peter Galton (Galton 1980). At the time, the author identified the type locality only as Ribamar. However, there are two localities with this name in Western Portugal, about 25 km from each other: Ribamar, in Lourinhã, and Ribamar, in Ericeira (Pereda-Superbiola et al., 2005, Fig. 1 therein). For 25 years, the type locality was the former. In 2005, Pereda-Superbiola and colleagues readdressed the issue by describing additional holotype material, articulated autopodial remains, and identifying the type locality as Ribamar from Ericeira, more to the South than previously thought.

The holotype (Fig. 1) is a partial ribcage with 13 dorsal vertebrae and five different types of dermal armor (Galton, 1980) and an incomplete autopodium with three metapodials and digits II, III and IV (Pereda-Superbiola et al., 2005). Based on the anatomy of the vertebrae and ribs, the presence of different types of dermal plates, consisting of very small isolated flat scutes, small medial paired circular plates with raised centers and rims, very long anterolateral plates, narrow nonprojecting overlapping dorsolateral plates and overlapping laterally projecting lateral plates, and ossified tendons, and later with the additional autopodium material, D. zbyszewskii was ascribed to Ankylosauria incertae sedis (Pereda-Superbiola et al., 2005). Additional material is needed to properly assess the validity of the taxon and its exact phylogenetic position.

 

Figure 1: Holotype of Dracopelta zbysewskii (IGM 5787). Photo by João Russo.

One of the most fascinating aspects of D. zbyszewskii is its age. It comes from the Late Jurassic of Portugal, close to the top of the Lourinhã formation. The Lourinhã formation is a continental fluvial depositional sequence of Late Kimmeridgian to latest Tithonian-earliest Berriasian? in age. Therefore, the occurrence of this taxon is particularly relevant since for the Late Jurassic there are three known ankylosaur taxa, Mymoorapelta maysi Kirkland & Carpenter 1994 and Gargoyleosaurus parkinorum Carpenter, Miles & Cloward 1998, from the Upper Jurassic Morrison Formation, in the USA, and D. zbyszewskii being the third. The relationships between these taxa and other basal members of the Ankylosauria may provide a valuable insight into the origin and evolution of the group as well as a clarification of the systematic position of D. zbyszewskii and “polacanthid” (sensu latum) ankylosaurs.

My research aims to clarify these points and bring D. zbyszewskii and its basal counterparts to a new light while establishing a proper, more in depth take on the phylogeny of the basal members of the Ankylosauridae and understanding the timing of the split between different groups within Ankylosauria and the evolution of the group.

Carpenter, K., Miles, C., and K. Cloward. 1998. Skull of a Jurassic ankylosaur (Dinosauria). Nature, 393: 782-783.

Carpenter, K. 2001. Phylogenetic analysis of the Ankylosauria; 455-483 in K. Carpenter (Ed.), The Armored Dinosaurs; Indiana University Press, Bloomington & Indianapolis, USA.

Coombs, W. P., and T. Maryańska. 1990. Ankylosauria; 456-483 in D. B. Weishampel, P. Dodson, and H. Osmólska (Eds.), The Dinosauria, University of California Press, Berkeley, USA.

Galton, P. M. 1980. Partial skeleton of Dracopelta zbyszewskii n. gen. and n. sp., an ankylosaurian dinosaur from the Upper Jurassic of Portugal. Geobios 13: 825-837.

Galton, P. M. 1983. Armored dinosaurs (Ornitischia: Ankylosauria) from the Middle and Upper Jurassic of Europe. Palaeontographica A, 182: 1-25.

Kirkland, J. I., and K. Carpenter. 1994. North America's first pre-Cretaceous ankylosaur (Dinosauria) from the Upper Jurassic Morrison Formation of Western Colorado. Brigham Young University Geology Studies, 40: 25-42.

Pereda-Superbiola, X., Dantas, P., Galton, P. M., and J. L. Sanz. 2005. Autopodium of the holotype of Dracopelta zbyszewskii (Dinosauria, Ankylosauria) and its type horizon and locality (Upper Jurassic: Tithonian, western Portugal). Neues Jahrbuch für Geologie und Paläontologie-Abhandlungen, 235(2): 175-196.