The dirty dozen: taxonomical and taphonomical overview of a unique ankylosaurian (Dinosauria: Ornithischia) assemblage from the Santonian Iharkút locality, Hungary

Abstract

Ankylosaurian fossils are usually standard elements of Cretaceous continental vertebrate localities, however bone-yielding horizons including more than one individual are extremely rare. Here we present a unique assemblage of 12 partial articulated or associated ankylosaurian skeletons and thousands of isolated bones and teeth discovered from the Santonian Iharkút vertebrate locality, western Hungary. Collected from an area of 600 m 2 and from a single bone bed, this material is one of the richest ankylosaurian accumulation worldwide. The 12 skeletons are not monospecific but, mostly based on the pelvic armor composition, six of them are from Hungarosaurus, two are referred to Struthiosaurus and four can be assigned to Nodosauridae indet. Sedimentological and taphonomical examinations revealed a single mass mortality event as the cause of the death and accumulation of these quadruped animals that are described here. The ankylosaur assemblage from Iharkút suggests at least a temporarily gregarious behavior of these animals and also shows that Hungarosaurus and Struthiosaurus might lived in the same moist habitat or at least preferred relatively close environments.

A new early branching armored dinosaur from the Lower Jurassic of southwestern China

“…To our knowledge, asymmetrical co-ossified bipartite osteoderms are present in the cervical armor of Scelidosaurus , Hungarosaurus, and Struthiosaurus ( Bunzel, 1871 ; Seeley, 1881 ; Pereda-Suberbiola and Galton, 2001 ; Ősi, 2005 ; Ősi et al, 2019 ; Norman, 2020b ), the lateral pectoral armor of Edmontonia and in a possible Early Jurassic ankylosaur from India ( Ford, 2000 ; Galton, 2019 ). Therefore, these bipartite osteoderms were most likely from the cervical or pectoral region.…”

Living alone or moving in herds? A holistic approach highlights complexity in the social lifestyle of Cretaceous ankylosaurs

“…This MDA may not be monospecific, as skeletal parts of two different nodosaurid ankylosaurian taxa, Hungarosaurus and cf. Struthiosaurus, have been identified in this material (Ősi and Pereda-Suberbiola, 2017;Ősi et al, 2019). Even though the precise taxonomic composition of this assemblage is not yet fully understood, these two nodosaurids are closely related taxa (Ősi andMakádi, 2009, Thompson et al, 2012), and have similar size J o u r n a l P r e -p r o o f and ecological role.…”

“…By contrast, the Iharkút nodosaurid MDA was deposited in a subtropical environment that lacked prolonged drought periods (Botfalvai et al, 2016). The taphonomical history of their MDA was reconstructed as a mass drowning event (Botfalvai et al, 2015;Ősi et al, 2019), similar to that of wildebeest during the annual migrations through the Serengeti plains (e.g. Capaldo and Peters, 1995;Myers and Storrs, 2007;Chiba et al, 2015;Subalusky et al, 2017).…”

“…J o u r n a l P r e -p r o o f With more than thousand isolated bones, and at least twelve associated and/or articulated partial skeletons, the Late Cretaceous (Santonian) dinosaur locality at Iharkút, Hungary, provided the richest ankylosaur assemblage from Europe (Ősi et al, 2019). Taphonomical investigation of the vertebrate material from this locality showed that ankylosaurs were the most dominant dinosaurs at Iharkút with a minimum number of 21 individuals and with their remains representing more than 25% of the total bone assemblage discovered to date (Botfalvai et al, 2015;Ősi et al, 2019). The bone-bearing layers (site SZ-6) were deposited by ephemeral, high-density flash-flood events probably trigged by episodic heavy rainfalls (Botfalvai et al, 2016).…”

A magyarországi bauxitok kutatásának rövid története (1903-2020)

“…A begyűjtött leletanyag tu domá nyos feldolgozásának eredményeit számos hazai és nemzetkö zi folyóirat és könyv őrzi (pl. ŐSI 2005;ŐSI & MAKÁDI 2009;ŐSI 2012;BOTFALVAI et al 2015BOTFALVAI et al , 2016ŐSI et al 2019).…”