Кешік Бор кезеңінің Анкилозавр тұқымдасы - Таларурус

Ankylosaurid dinosaur genus from the Late Cretaceous

Talarurus (,/t//æ//l//ə/'/r//ʊər//ə//s/ TALəROORəs; meaning "basket tail" or "wicker tail") is a genus of ankylosaurid dinosaur that lived in Asia during the Late Cretaceous period, about 96 million to 89 million years ago. The first remains of Talarurus were discovered in 1948 and later described by the Russian paleontologist Evgeny Maleev with the type species T. plicatospineus. It is known from multiple yet sparse specimens, making it one of the most well known ankylosaurines, along with Pinacosaurus. Elements from the specimens consists of various bones from the body; five skulls have been discovered and assigned to the genus, although the first two were very fragmented. It was a medium sized, heavily built, ground dwelling, quadrupedal herbivore, that could grow up to long and weighed about , nearly a ton. Like other ankylosaurs it had heavy armour and a club on its tail, limiting its speed. Talarurus is classified as a member of the Ankylosauria, in the Ankylosaurinae, a group of derived ankylosaurs. Talarurus is known from the Bayan Shireh Formation, being likely niche partitioned with Tsagantegia, as indicated by its muzzle, which has a rectangular shape specialized for grazing. These represent the oldest known ankylosaurines from Asia, although they are not very closely related to each other. It appears that the closest relative of Talarurus was Nodocephalosaurus, an ankylosaurin with similar facial osteoderms. Most of the skeletal mounts of Talarurus are outdated by numerous issues, such as the ribs pointing downward instead of to the sides, as in most ankylosaurs; an inaccurate skull cast which is mainly based on related species and not on the available skull material; very splayed arms and legs; four digits on the feet, which in reality only had three as indicated by related ankylosaurines. All of these mistakes were made by anatomical misunderstandings since ankylosaurs were not fully known at that time, also, Talarurus is not known from a complete skeleton.

Talarurus remains have been discovered in the southeastern parts of the Gobi Desert in what is now Mongolia. The holotype specimen PIN 557 91 was discovered in 1948 by the Joint Soviet Mongolian Paleontological Expedition, and unearthed from sandy, red calcareous claystone at the Baynshire locality of the Bayan Shireh Formation. Talarurus was described and named by the Russian paleontologist Evgeny Maleev in 1952. Specimen PIN 557, the original holotype designated by Maleev, included a fragmentary skull with the posterior part of the skull roof, including the occipital region and the basicranium, numerous vertebrae, several ribs, a scapulocoracoid, a humerus, a radius, an ulna, a nearly complete manus, a partial ilium, an ischium, a femur, a tibia, a fibula, a nearly complete pes, and assorted armor and scutes. The generic name, Talarurus, is derived from the Greek τάλαρος ("tálaros", meaning basket or wicker cage) and οὐρά ("ourā́", meaning rear or tail), in a reference to the club end of the tail which bears resemblance to a wicker basket, and the length of the tail which consists of interlaced bony struts, reminiscent of the weave that is employed when making wicker baskets. The specific name, "plicatospineus", is derived from the Latin plicātus (meaning folded) and spīneus (meaning thorny or spiny), in a reference to the numerous osteoderms that gave form to its armor in life. In fact it consisted of fragmentary remains of six individuals discovered at the site. In 1977, Teresa Maryańska chose PIN 557 91, a posterior rear of the skull, as the holotype, given the irregularities of the combined individuals. Also, she renamed Syrmosaurus disparoserratus into a second species: Talarurus disparoserratus. However, in 1987, this was remade into the separate genus Maleevus. Since 2006, in the context of the Korea Mongolia Joint International Dinosaur Project, numerous additional specimens have been referred to Talarurus, found at the Baynshire and Shine Us Khuduk localities. These in 2014 were still undescribed. These specimens were described on detail in 2019, consisting of three medium preserved skulls with additional anatomical and ecological data for Talarurus. This new material is now permanently housed at the Institute of Paleontology and Geology of the Mongolian Academy of Sciences.

Initially, Maleev described Talarurus as having four digits on the foot. however, Holtz estimated it around Like other ankylosaurids, it had a wide rostrum (beak), a formidable osteoderms running across its body, forming an extensive armor, and the famous tail club. Its limbs were robust and short, supporting a wide and rounded belly. Due to the partial preservation of the specimens, the exact osteoderm arrangement is unknown, however, some have been unearthed. The preserved osteoderms are very sparse, consisting of some cervical halfrings and spine shaped body osteoderms. The osteoderms are strongly robust, most spine shaped osteoderms measured in height. Maryańska demonstrated that it differed from Euoplocephalus, citing the shape of the skull, the morphology of the palate, and the presence of four pedal digits. However, Arbour in 2014 recovered trees in which Talarurus was more closely related to North American forms than to Asian ankylosaurids. In some of these Talarurus was the sister species of Nodocephalosaurus. According to Park et al. 2019, Talarurus filled the niche of a grazer herbivore, whereas Tsagantegia, another ankylosaurid from the formation, filled the niche of a browser herbivore. For instance, Talarurus had a broad and rectangular snout (or beak), useful for low vegetation, while the one in Tsagantegia is more elongated and shovel shaped, useful for high vegetation. In order to illustrate this differentiation strategy, they compared the ankylosaurids to the extant African white and black rhinoceros: the white rhinoceros is equipped with a broad and rectangular snout, specialized for grazing. The black rhinoceros in the other hand, has a pointed snout for browsing. With these anatomical features and example, it is clear that these taxa were niche partitioned. Found in Late Cretaceous localities such as Baynshire and Bayshin Tsav, taxa that were contemporaneous with Talarurus in the Upper Bayan Shireh included a diverse dinosaur fauna, such as the large dromaeosaurid Achillobator, the therizinosaurids Erlikosaurus and Segnosaurus, the small and likely immature ceratopsid Graciliceratops, the small hadrosauroid Gobihadros, Based on the caliche, fluvial and lacustrine sedimentation, the Bayan Shireh Formation was a large semiarid terrain with meanders and lakes, along with the strong presence of angiosperm and gymnosperm plants all over the zone. According to some biostratigraphic occurrences within Asiatic formations, there was a likely correlation between the Iren Dabasu Formation and the Bayan Shireh Formation.