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''Talarurus'' ( ; meaning "basket tail" or "wicker tail") is a genus of
ankylosaurid Ankylosauridae () is a family of armored dinosaurs within Ankylosauria, and is the sister group to Nodosauridae. The oldest known Ankylosaurids date to around 122 million years ago and went extinct 66 million years ago during the Cretaceous–Pal ...
dinosaur that lived in
Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...
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 Evgeny Aleksandrovich Maleev (, ; 25 February 1915 – 12 April 1966) was a Soviet and Russian paleontologist who did most of his research on reptiles and Asian fossils, such as the naming of the ankylosaur '' Talarurus'' and theropods '' Tar ...
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 ''Pinacosaurus'' (meaning "Plank lizard") is a genus of ankylosaurid thyreophoran dinosaur that lived in Asia during the Late Cretaceous (Santonian-Campanian, roughly 75 million to 71 million years ago), mainly in Mongolia and China. The first ...
''. 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 Quadrupedalism is a form of locomotion where four limbs are used to bear weight and move around. An animal or machine that usually maintains a four-legged posture and moves using all four limbs is said to be a quadruped (from Latin ''quattuor ...
herbivore A herbivore is an animal anatomically and physiologically adapted to eating plant material, for example foliage or marine algae, for the main component of its diet. As a result of their plant diet, herbivorous animals typically have mouthp ...
, that could grow up to long and weighed about , nearly a ton. Like other ankylosaurs it had heavy
armour Armour (British English) or armor (American English; see spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, especially direct contact weapons or projectiles during combat, or fr ...
and a
club Club may refer to: Arts, entertainment, and media * ''Club'' (magazine) * Club, a ''Yie Ar Kung-Fu'' character * Clubs (suit), a suit of playing cards * Club music * "Club", by Kelsea Ballerini from the album ''kelsea'' Brands and enterprises ...
on its tail, limiting its speed. ''Talarurus'' is classified as a member of the
Ankylosauria Ankylosauria is a group of herbivorous dinosaurs of the order Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms, similar to turtles. Ankylosaurs were bulky quadrupeds, with short, powerful limbs. ...
, in the
Ankylosaurinae Ankylosaurinae is a subfamily of ankylosaurid dinosaurs, existing from the Early Cretaceous about 105 million years ago until the end of the Late Cretaceous, about 66 mya. Many genera are included in the clade, such as ''Ankylosaurus'', ''Pinacos ...
, a group of derived ankyosaurs. ''Talarurus'' is known from the Bayan Shireh Formation, being likely niche partitioned with ''
Tsagantegia ''Tsagantegia'' (; meaning Tsagan Teg) is a genus of medium-sized ankylosaurid thyreophoran dinosaur that lived in Asia during the Late Cretaceous period. The genus is monotypic, including only the type species, ''T. longicranialis''. The specime ...
'', 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 ''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-n ...
'', 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.


History of discovery

''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 Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone, slate, and shale. Most of the particles of which the stone is composed are less than and are too sma ...
at the Baynshire locality of the Bayan Shireh Formation. ''Talarurus'' was described and named by the
Russia Russia (, , ), or the Russian Federation, is a transcontinental country spanning Eastern Europe and Northern Asia. It is the largest country in the world, with its internationally recognised territory covering , and encompassing one-eight ...
n
paleontologist Paleontology (), also spelled palaeontology or palæontology, is the scientific study of life that existed prior to, and sometimes including, the start of the Holocene epoch (roughly 11,700 years before present). It includes the study of foss ...
Evgeny Maleev Evgeny Aleksandrovich Maleev (, ; 25 February 1915 – 12 April 1966) was a Soviet and Russian paleontologist who did most of his research on reptiles and Asian fossils, such as the naming of the ankylosaur '' Talarurus'' and theropods '' Tar ...
in
1952 Events January–February * January 26 – Black Saturday in Egypt: Rioters burn Cairo's central business district, targeting British and upper-class Egyptian businesses. * February 6 ** Princess Elizabeth, Duchess of Edinburgh, becomes ...
. 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 The occipital bone () is a cranial dermal bone and the main bone of the occiput (back and lower part of the skull). It is trapezoidal in shape and curved on itself like a shallow dish. The occipital bone overlies the occipital lobes of the cere ...
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 Armour (British English) or armor (American English; see spelling differences) is a covering used to protect an object, individual, or vehicle from physical injury or damage, especially direct contact weapons or projectiles during combat, or fr ...
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 ''Maleevus'' (named in honour of Evgeny Maleev) is an extinct genus of herbivorous ankylosaurid dinosaur from the late Cretaceous, around 90 million years ago (possibly 98-83 Ma), of Mongolia. Discovery and naming Between 1946 and 1949, Soviet-M ...
''. Elements of all these specimens were combined into a skeletal mount exhibited at the Orlov Museum. Although very complete, in several aspects the mount is strongly inaccurate. The type and only valid
species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...
known today is ''Talarurus plicatospineus''. ''Talarurus'' is now known from at least a dozen individual specimens from various localities. Specimen PIN 3780/1 was collected from terrestrial sediments at the Bayshin-Tsav locality of the Bayan Shireh Formation, by a joint Soviet-Mongolian Paleontological Expedition in 1975 and is now reposited at the Paleontological Institute, Russian Academy of Sciences, in Moscow. This material was assigned to ''Talarurus'' and is also considered to date from the Turonian stage of the Cretaceous. This specimen consists of the top of a skull and a fragmentary skeleton. 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. Another specimen referred to this genus from the Bayshin Tsav locality is composed of an (undescribed) incomplete skull with cranial roof, occipital part and braincase. A second undescribed specimen, collected at the Baga Tarjach locality, consists of a fragment of a maxilla with eight teeth. Arbour have listed many of the referred and additional material for ''Talarurus''. Even more additional material has been found. In 2007 during the Korea-Mongolia International Dinosaur Expedition, specimens MPC-D 100/1354, MPC-D 100/1355, and MPC-D 100/1356 were collected from the eastern part of the Gobi Desert, at the Bayn Shire locality in the Bayan Shireh Formation. These specimens were described on detail in
2019 File:2019 collage v1.png, From top left, clockwise: Hong Kong protests turn to widespread riots and civil disobedience; House of Representatives votes to adopt articles of impeachment against Donald Trump; CRISPR gene editing first used to experim ...
, 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.


Description

Initially, Maleev described ''Talarurus'' as having four digits on the foot. However, the foot was not found in articulation; the mounted foot is a composite, and three is the more likely number as all other known ankylosaurids show three toes; earlier reports that ''
Pinacosaurus ''Pinacosaurus'' (meaning "Plank lizard") is a genus of ankylosaurid thyreophoran dinosaur that lived in Asia during the Late Cretaceous (Santonian-Campanian, roughly 75 million to 71 million years ago), mainly in Mongolia and China. The first ...
'' also possessed four are incorrect. Another presumed characteristics: the osteoderms had a furrowed ornamentation, making a specially formidable armor, with each plate adorned with additional pleated spines. These were also based on a misunderstanding. These were segments of the halfrings protecting the neck, with their typical low keels. The mount has the further peculiarity that it shows ''Talarurus'' as built like a
hippopotamus The hippopotamus ( ; : hippopotamuses or hippopotami; ''Hippopotamus amphibius''), also called the hippo, common hippopotamus, or river hippopotamus, is a large semiaquatic mammal native to sub-Saharan Africa. It is one of only two extant ...
, with a barrel-shaped thorax, not with the characteristic ankylosaurid low and wide body type, and the forelimbs are strongly splayed. This was caused by an incorrect positioning of the ribs as if they were appending instead of sticking out sideways; this mistake also prevented a mounting of the wide upper pelvic elements.


Size and distinguishing traits

''Talarurus'' was a medium sized ankylosaur,
Thomas Holtz Thomas Richard Holtz Jr. (born September 13, 1965) is an American vertebrate palaeontologist, author, and principal lecturer at the University of Maryland's Department of Geology. He has published extensively on the phylogeny, morphology, ecomor ...
and Gregory S. Paul estimated its length at , Paul gave a weight of , however, Holtz estimated it around . Like other ankylosaurids, it had a wide
rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ships * R ...
(beak), a formidable osteoderms running across its body, forming an extensive armor, and the famous
tail club In zoology, a club is a bony mass at the end of the tail of some dinosaurs and of some mammals, most notably the ankylosaurids and the glyptodonts, as well as meiolaniid turtles. It is thought that this was a form of defensive armour or weapon th ...
. Its limbs were robust and short, supporting a wide and rounded belly. Diagnoses provided by Maleev 1956 and Tumanova 1987, were of limited utility as they largely listed traits shared with many other ankylosaurids.
Arbour Arbor(s) or Arbour(s) may refer to: Arts and entertainment * ''Arbor'' (installation), a 2013 public artwork in Indianapolis, Indiana, US * Arbor, a counterweight-carrying device found in theater fly systems * ''The Arbor'', a 1980 play by Andr ...
also noted that the foot in fact had three toes. She established a single
autapomorphy In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to ...
: on the frontals, at the middle skull roof, a raised V- shaped region is present. Also she determined that ''Talarurus'' differed from all known ankylosaurids with the exception of the American ''Nodocephalosaurus'' in the possession of caputegulae on the frontals and nasals, that are cone-shaped with a circular base. However, according to Parks et al. 2019, ''Talarurus'' can be distinguished based on diverse rostral characteristics, such as the prominent internarial caputegula, elongated caputegulae, the numerous caputegulae surrounding the nasal area, conical/polygonal-shaped caputegulae, among others.


Skull

The skull of ''Talarurus'' measured about in total length. The holotype, PIN 557-91, is based only on a posterior skull roof, which features tubercle-like caputegulae (facial osteoderms or armor tiles) that resemble those of ''
Nodocephalosaurus ''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-n ...
''. As noted by Arbour and Currie, the skull roof of PIN 3780/1 appears to have slightly different caputegulae (head osteoderms or armour tiles), and that it was unclear if this represents a taxonomic issue. Nevertheless, all the referred skulls share the same patterns of caputegulae (although little variation among individuals is observable) and therefore referable to the genus. The most complete skull is MPC-D 100/1354. It nicely preserves the maxillary rostrum, which is broad and semi-rectangular in shape and fused, no
teeth A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tea ...
are found in this zone; probably useful on flat surfaces. As expected, the caputegulae are poligon to tubercle-shaped, with some being present on the nasal area. Each maxilla preserves 23
alveoli Alveolus (; pl. alveoli, adj. alveolar) is a general anatomical term for a concave cavity or pit. Uses in anatomy and zoology * Pulmonary alveolus, an air sac in the lungs ** Alveolar cell or pneumocyte ** Alveolar duct ** Alveolar macrophage * M ...
, however, the teeth were not preserved. Most of the caputegulae present in the top of the head are hexagonal in shape, in the holotype PIN 557-91 some are triangular. The orbitals are strongly armored with some osteoderms behind them. In MPC-D 100/1355 and MPC-D 100/1356 the
squamosal The squamosal is a skull bone found in most reptiles, amphibians, and birds. In fishes, it is also called the pterotic bone. In most tetrapods, the squamosal and quadratojugal bones form the cheek series of the skull. The bone forms an ancestral co ...
and
quadratojugal The quadratojugal is a skull bone present in many vertebrates, including some living reptiles and amphibians. Anatomy and function In animals with a quadratojugal bone, it is typically found connected to the jugal (cheek) bone from the front and ...
horns are thick and triangular, with the squamosals being more rounded. Usually, the lower jaw remains of ''Talarurus'' do not preserve, however, MPC-D 100/1355 was found in association with a right
dentary In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...
, very fragmented though.


Postcranial skeleton

Most of the postcranial remains are known from fragmentary individuals. Based on the PIN 557 specimens, the ribs are strongly curved and thickened, having a length ranging between . The vertebral area is partially missing, preserving some cervicals, dorsals, caudals and the sacrum. The cervical vertebrae are amphicoelous (concave on both sides) with thickened centra (body), the
neural arches The spinal column, a defining synapomorphy shared by nearly all vertebrates,Hagfish are believed to have secondarily lost their spinal column is a moderately flexible series of vertebrae (singular vertebra), each constituting a characteristic i ...
are slightly higher. The dorsals have high, wide centra, and they are also amphicoelous with very elongated and robustly built neural arches; some are broken. More complete than the previous sections, the sacrum consists of 4 presacrals, 4 sacrals, and the first caudal vertebra, these vertebrae are fused together, with some ribs attached. Their size gradually increases from backward to forwards. Some isolated caudal vertebrae are present, they seem to indicate that the tail consisted of approximately 25 to 30 caudals. The anteriormost caudals have somewhat elongated neural arches and centra, the
chevrons Chevron (often relating to V-shaped patterns) may refer to: Science and technology * Chevron (aerospace), sawtooth patterns on some jet engines * Chevron (anatomy), a bone * '' Eulithis testata'', a moth * Chevron (geology), a fold in rock l ...
are fused and triangle-shaped. In contrast, the posteriormost caudals have very flattened chevrons and neural arches. Due to the partial preservation of the specimens, the exact
osteoderm Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinct amp ...
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. MPC-D 100/1355 was found in association with a partial halfring, as well as other body elements. Only the left manus is preserved, it is virtually complete preserving five digits, only lacking some unguals and phalanges. The preserved left pes is very unique; it was described as having four digits, this statement however, was proved to be a product of the initial skeleton mount and three digits is more accurate/likely, as seen in related ankylosaurines. In general terms, both manus and pes
metatarsals The metatarsal bones, or metatarsus, are a group of five long bones in the foot, located between the tarsal bones of the hind- and mid-foot and the phalanges of the toes. Lacking individual names, the metatarsal bones are numbered from the me ...
are strongly robust and stocky. The
shoulder girdle The shoulder girdle or pectoral girdle is the set of bones in the appendicular skeleton which connects to the arm on each side. In humans it consists of the clavicle and scapula; in those species with three bones in the shoulder, it consists of ...
is represented by a scapulocoracoid that measures about long,
humerus The humerus (; ) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of a round ...
, radius and
ulna The ulna (''pl''. ulnae or ulnas) is a long bone found in the forearm that stretches from the elbow to the smallest finger, and when in anatomical position, is found on the medial side of the forearm. That is, the ulna is on the same side of t ...
, these elements are very robust compared to other postcrania and they pertain to the left arm. The left scapulocoracoid is very robust with a well developed insertion for the humerus ( glenoid), although the scapular blade is somewhat shortened in length. The humerus is very wide at the ends and thickened measuring long; it shows some resemblance to that of '' Ankylosaurus''. Although fragmentary, the pelvic girdle is represented by a partial and flattened ilium with the ischium. Hindlimb elements include the right femur and left tibia. The preserved femur is straight and strongly robust, the greater trochanter is fused with the lesser trochanter; it measures long. The tibia however, is more shortened but greatly wide, it has a total length of . In addition, a fibula was also preserved, it has a length of . Overall, the fibula is more straight and thin compared to the femur and tibia, its distal end is more wide than the proximal end.


Classification

Ankylosaurid phylogenetic relations are hard to determine because many taxa are only partially known, the exact armour configuration has rarely been preserved, fused osteoderms obscure many details of the skull and the Ankylosauridae are conservative in their postcranial skeleton, showing little variation in their vertebrae, pelves and limbs. Previously it was assumed that as one of the oldest known ankylosaurids, ''Talarurus'' possessed some basal characters that are shared with
nodosaurids Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous period in what is now North America, South America, Europe, and Asia. Description Nodosaurids, like their close relatives the ankylosaurids, we ...
but were later lost in more advanced ankylosaurs, such as the presence of four toes. However, the presumed "primitive" traits proved to be largely artefacts of the initial skeletal restoration. Recent phylogenetic analysis provides evidence for an assignment of ''Talarurus'' to the
Ankylosaurinae Ankylosaurinae is a subfamily of ankylosaurid dinosaurs, existing from the Early Cretaceous about 105 million years ago until the end of the Late Cretaceous, about 66 mya. Many genera are included in the clade, such as ''Ankylosaurus'', ''Pinacos ...
, a derived ankylosaurid group. This can be reconciled with its relatively old geological age by the possibility that the Ankylosauridae as a whole appeared much earlier during the
Early Jurassic The Early Jurassic Epoch (in chronostratigraphy corresponding to the Lower Jurassic Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-Jurassic extinction event, 201.3 Ma&nb ...
, which must have been true if they were the sister group of the Nodosauridae in the sense proposed by Coombs in 1978; i.e. if all polacanthines were nodosaurids. ''Talarurus'' was assigned to the Syrmosauridae (now known as Ankylosauridae) by Maleev in its original description in 1952. Walter Preston Coombs suggested that it was the same dinosaur as '' Euoplocephalus'' although subsequent study did not support this assertion. 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. Vickaryous et al. 2004 note the presence of two distinct ankylosaurid clades during the Late Cretaceous, one consisting of North American
taxa In biology, a taxon (back-formation from ''taxonomy''; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit. Although neither is required, a taxon is usually known by a particular nam ...
and the other restricted to Asian taxa. 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 In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...
of ''Nodocephalosaurus''.


Paleobiology

The 2007 specimen skulls have brought new insights into the neurocranial capacities and dietary habits of ''Talarurus'', specifically the specimen MPC-D 100/1354, which is a well-preserved, almost complete cranium. MPC-D 100/1354 was described in extensive detail along with a very complete skull of '' Tarchia'' by Paulina-Carabajal et al. 2017. They noted that
ankylosaurids Ankylosauridae () is a family of armored dinosaurs within Ankylosauria, and is the sister group to Nodosauridae. The oldest known Ankylosaurids date to around 122 million years ago and went extinct 66 million years ago during the Cretaceous–Pal ...
had well-developed gaze stabilization and auditive senses, differing from
nodosaurids Nodosauridae is a family of ankylosaurian dinosaurs, from the Late Jurassic to the Late Cretaceous period in what is now North America, South America, Europe, and Asia. Description Nodosaurids, like their close relatives the ankylosaurids, we ...
, by examining the endocranial region of the selected specimens. The presence of the flocculus was first reported in ''Talarurus'' by Maryańska and later in other related ankylosaurids, however, this lobe seems to be absent or reduced in nodosaurids. The flocculus is relatively large on most ankylosaurids. Another neuroanatomical character is the elongated lagena, which is prominent in '' Euoplocephalus'', ''Tarchia'' and ''Talarurus''. This anatomical feature indicates that ankylosaurids had a large range of
sound perception Psychoacoustics is the branch of psychophysics involving the scientific study of sound perception and audiology—how humans perceive various sounds. More specifically, it is the branch of science studying the psychological responses associated wit ...
, especially for low frequencies. In addition to these findings, the preserved
rostrum Rostrum may refer to: * Any kind of a platform for a speaker: **dais **pulpit * Rostrum (anatomy), a beak, or anatomical structure resembling a beak, as in the mouthparts of many sucking insects * Rostrum (ship), a form of bow on naval ships * R ...
in MPC-D 100/1354 is broad, almost rectangular in shape and somewhat stocky. The wide rostrum of ''Talarurus'' probably worked with efficiency on low vegetation at flat terrain. Evidence seems to indicate that ''Talarurus'' had a grazer feeding-method.


Paleoenvironment

The fossil remains of ''Talarurus'' have been found in the sediments of Bayan Shireh Formation, which are thought to date from the Cenomanian to
Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya (million years ago) and 83.6 ± 0.7 mya. T ...
stages Stage or stages may refer to: Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly British theatre newspaper * St ...
of the Late Cretaceous period, about 96 million to 89 million years ago. According to Park et al. 2019, ''Talarurus'' filled the niche of a
grazer Grazer may refer to: *grazer, an animal that grazes *Grazer, a native or inhabitant of Graz *GRAZER, the shoegaze band GRAZER Astronomy * Earth Grazer, Earth-grazing fireball that enters the Earth's atmosphere and leaves again * Mercury grazer, ...
herbivore, whereas ''
Tsagantegia ''Tsagantegia'' (; meaning Tsagan Teg) is a genus of medium-sized ankylosaurid thyreophoran dinosaur that lived in Asia during the Late Cretaceous period. The genus is monotypic, including only the type species, ''T. longicranialis''. The specime ...
'', 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 Black is a color which results from the absence or complete absorption of visible light. It is an achromatic color, without hue, like white and grey. It is often used symbolically or figuratively to represent darkness. Black and white have of ...
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. Another case of niche partitioning can be observed on the therizinosaurids ''Erlikosaurus'' and ''Segnosaurus'', taxa that were also discovered in the formation. 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 ''Achillobator'' ( ; meaning "Achilles hero") is a genus of large dromaeosaurid dinosaurs that lived in Asia during the Late Cretaceous period about 96 million to 89 million years ago in what is now the Bayan Shireh Formation. The genus is curren ...
'', the therizinosaurids ''
Erlikosaurus ''Erlikosaurus'' (meaning " Erlik's lizard") is a genus of therizinosaurid that lived in Asia during the Late Cretaceous period. The fossils, a skull and some post-cranial fragments, were found in the Bayan Shireh Formation of Mongolia in 1972, ...
'' and '' Segnosaurus'', the ornithomimosaur ''
Garudimimus ''Garudimimus'' (meaning "Garuda mimic") is a genus of ornithomimosaur that lived in Asia during the Late Cretaceous. The genus is known from a single specimen found in 1981 by a Soviet-Mongolian paleontological expedition in the Bayan Shireh Fo ...
'', the small and likely immature ceratopsid ''
Graciliceratops ''Graciliceratops'' (meaning "slender horn") is a genus of neoceratopsian dinosaurs that lived in Asia during the Late Cretaceous period. Discovery and naming The holotype, ZPAL MgD-I/156, was discovered at the Bayan Shireh Formation in Mongoli ...
'', the small hadrosauroid '' Gobihadros'', and its ecological counterpart, ''
Tsagantegia ''Tsagantegia'' (; meaning Tsagan Teg) is a genus of medium-sized ankylosaurid thyreophoran dinosaur that lived in Asia during the Late Cretaceous period. The genus is monotypic, including only the type species, ''T. longicranialis''. The specime ...
''. Based on the
caliche Caliche () is a sedimentary rock, a hardened natural cement of calcium carbonate that binds other materials—such as gravel, sand, clay, and silt. It occurs worldwide, in aridisol and mollisol soil orders—generally in arid or semiarid regions ...
, fluvial and
lacustrine A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...
sedimentation, the Bayan Shireh Formation was a large
semiarid A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi-ar ...
terrain with
meanders A meander is one of a series of regular sinuous curves in the channel of a river or other watercourse. It is produced as a watercourse erodes the sediments of an outer, concave bank (cut bank) and deposits sediments on an inner, convex bank ...
and lakes, along with the strong presence of
angiosperm Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...
and gymnosperm plants all over the zone. According to some
biostratigraphic Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock strata by using the fossil assemblages contained within them.Hine, Robert. “Biostratigraphy.” ''Oxford Reference: Dictionary of Bi ...
occurrences within Asiatic formations, there was a likely correlation between the
Iren Dabasu Formation The Iren Dabasu Formation (also known as Erlian Formation) is a Late Cretaceous geologic formation in the Iren Nor region of Inner Mongolia. Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the ...
and the Bayan Shireh Formation.


See also

*
Timeline of ankylosaur research This timeline of ankylosaur research is a chronological listing of events in the history of paleontology focused on the ankylosaurs, quadrupedal herbivorous dinosaurs who were protected by a covering bony plates and spikes and sometimes by a club ...


References


External links

* {{Taxonbar, from=Q131940 Ankylosaurids Late Cretaceous dinosaurs of Asia Fossil taxa described in 1952 Taxa named by Evgeny Maleev Ornithischian genera