Жоғалған бассүйекді динозавр - Nodocephalosaurus

Extinct genus of dinosaurs

Nodocephalosaurus (meaning "knob headed lizard") is a monospecific genus of ankylosaurid dinosaur from New Mexico that lived during the Late Cretaceous (late Campanian to early Maastrichtian stage, 73.49 to 73.04 Ma) in what is now the De na zin member of the Kirtland Formation. The type and only species, Nodocephalosaurus kirtlandensis, is known only from a partial skull. It is closely related and shares similar cranial anatomy to Akainacephalus. In 2006, Robert M. Sullivan and Denver W. Fowler referred four additional specimens: SMPVP 1957, two cranial osteoderms; SMP VP 1870, a left cervical spine; SMP VP 1149, the seventh or eighth caudal vertebrae; and SMP VP 1743, the first caudal vertebra. The specimens were referred to Nodocephalosaurus as, at the time, it was the only named ankylosaurid from the Kirtland Formation. These three additional specimens were referred to the genus based on the similar surface texture to the holotype specimen.

In 2016, Gregory S. Paul gave Nodocephalosaurus an estimated length of 4.5 metres (15 feet) and a weight of 1.5 tonnes (3,306 lbs). Thompson et al. (2012) found Nodocephalosaurus to be sister taxon to a clade containing Talarurus, Tianzhenosaurus, Tarchia and Saichania, while Arbour & Currie (2015) found it to be sister taxon to Talarurus, Zheng et al. (2018), and Rivera Sylva et al. (2018). The results of an analysis by Arbour & Currie (2015) are reproduced below.

Nodocephalosaurus is known from the De na zin member of the Kirtland Formation which has been dated to the upper most Campanian to lower most Maastrichtian stage, 73.49 ± 0.25 to 73.04 ± 0.25 Ma, and may be a taxon unique to the Willow Wash local fauna. The Kirtland Formation lies on the western margin of the Western Interior Seaway and represents a floodplain that was abundant with ferns, conifers and flowering plants. Based on the abundance of angiosperms with leaves that have entire or nearly entire margins and drip points, the Kirtland Formation may have had a warm temperate to subtropical climate. Nodocepahlosaurus coexisted with the saurolophine hadrosaurids Anasazisaurus, Kritosaurus and Naashoibitosaurus, the chasmosaurine ceratopsid Pentaceratops, the pachycephalosaurid Sphaerotholus, the ankylosaurine ankylosaurid Ziapelta, and an indeterminate ornithomimid. Non dinosaur taxa contemporaneous with Nodocephalosaurus include an indeterminate choristodere, Brachychampsa and Leidyosuchus, the turtles Basilemys, Denazinemys, Neurankylus, Plastomenus and Thescelus, and the fishes Melvius and Myledaphus.