''Bissektipelta'' (meaning " Bissekty shield") is a genus of ankylosaurine thyreophoran

dinosaurs Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

that lived in

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

during the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

in what is now the

Bissekty Formation The Bissekty Formation (sometimes referred to as Bissekt) is a formation (geology), geologic formation and Lagerstätte which outcrop, crops out in the Kyzyl Kum desert of Uzbekistan, and dates to the Late Cretaceous Period (geology), Period. Laid ...

Uzbekistan , image_flag = Flag of Uzbekistan.svg , image_coat = Emblem of Uzbekistan.svg , symbol_type = Emblem of Uzbekistan, Emblem , national_anthem = "State Anthem of Uzbekistan, State Anthem of the Republ ...

. ''Bissektipelta'' is a

monospecific In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

genus, containing only the type species ''B. archibaldi''.

History of discovery

In September 1998, the joint Uzbek-Russian-British-American-Project excavated the

braincase In human anatomy, the neurocranium, also known as the braincase, brainpan, brain-pan, or brainbox, is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calv ...

of an ankylosaur. In

2002 The effects of the September 11 attacks of the previous year had a significant impact on the affairs of 2002. The war on terror was a major political focus. Without settled international law, several nations engaged in anti-terror operation ...

, Alexandr Averianov, based on this find, named a second species of the genus '' Amtosaurus'': ''Amtosaurus archibaldi''. The specific name honours James David Archibald, leading the URBAC (Uzbekistan, Russia, Britain, America, & Canada) project that performed the excavation. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

specimen, ZIN PH 1/6, was collected from the

, dating from the late

Turonian The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...

- Coniacian, of Dzharakuduk. It consists of a well-preserved, fully ossified braincase with a partial skull roof, along with isolated teeth and

osteoderms Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of Extant taxon, extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, Temnospondyli, ...

. In

2004 2004 was designated as an International Year of Rice by the United Nations, and the International Year to Commemorate the Struggle Against Slavery and Its Abolition (by UNESCO). Events January * January 3 – Flash Airlines Flight 60 ...

, Jolyon Parish and Paul Barrett concluded that the

type species In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...

of ''Amtosaurus'', ''Amtosaurus magnus'', was a ''

nomen dubium In binomial nomenclature, a ''nomen dubium'' (Latin for "doubtful name", plural ''nomina dubia'') is a scientific name that is of unknown or doubtful application. Zoology In case of a ''nomen dubium,'' it may be impossible to determine whether a ...

'', a dubious name. This implied that no other species could be validly referred to the genus ''Amtosaurus''. ''A. archibaldi'' should be reassigned to a new

taxon In biology, a taxon (back-formation from ''taxonomy''; : 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 name and ...

. They renamed the genus as ''Bissektipelta'' with the generic name combining a reference to the geological formation with a

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''pelta'' (meaning small shield), which is derived from the

Greek Greek may refer to: Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group *Greek language, a branch of the Indo-European language family **Proto-Greek language, the assumed last common ancestor of all kno ...

''peltè'' (meaning shield). The type species is the original ''A. archibaldi'' but the

new combination In Taxonomy (biology), biological taxonomy, a combinatio nova (abbreviated comb. nov. or n. comb.) refers to the formal renaming of an organism's scientific name when it is transferred to a different genus, reclassified within a different specie ...

is ''Bissektipelta archibaldi''. Two additional specimens were referred to by Kuzmin and colleagues in

2020 The year 2020 was heavily defined by the COVID-19 pandemic, which led to global Social impact of the COVID-19 pandemic, social and Economic impact of the COVID-19 pandemic, economic disruption, mass cancellations and postponements of even ...

. These consist of ZIN PH 281/16, a smaller but well-preserved partial braincase with open sutures between some bones and ZIN PH 2329/16, another braincase similar in size to the holotype that is slightly damaged and mixed up within the sediment layer.

Description

Parish & Barrett indicated some distinguishing traits of ''Bissektipelta''. One of these is an

autapomorphy In phylogenetics, an autapomorphy is a distinctive feature, known as a Synapomorphy, 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 (cladistics), outgroup taxa, not ...

, a unique derived character. On the top skull roof grooves are present, together forming a truncated "Y" and separating three polygonal areas of flat remodelled bone tissue. These grooves reflected the position of skull osteoderms. Averianov had in 2002 proposed three traits in which ''A. archibaldi'' differed from ''A. magnus''. Its braincase has three exits for the '' Nervus hypoglossus'' (

cranial nerve Cranial nerves are the nerves that emerge directly from the brain (including the brainstem), of which there are conventionally considered twelve pairs. Cranial nerves relay information between the brain and parts of the body, primarily to and f ...

XII) instead of two. It also has a more limited angle of 90° between the ventral surfaces of the basioccipital and the basisphenoid, and more caudally, to the rear, situated basipterygoid processes. In 2004, these were no longer considered unique traits but the triple exits were seen as rare.

Classification

When described in 2002, Averianov placed ''A. archibaldi'' in the

Ankylosauridae 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 ...

. Parish & Barrett thought such precision was unwarranted and placed the newly ''Bissektipelta'' in a more general

Ankylosauria Ankylosauria is a group of herbivorous dinosaurs of the clade 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 ...

. However, Victoria M. Arbour and Philip J. Currie affirmed the position within the Ankylosauridae. Based on numerous cranial traits, Kuzmin and colleagues have placed ''Bissektipelta'' within the advanced Ankylosaurinae in a basal position and confirmed its valid taxonomic status.

Paleobiology

2019 This was the year in which the first known human case of COVID-19 was documented, preceding COVID-19 pandemic, the pandemic which was declared by the World Health Organization the following year. Up to that point, 2019 had been described as ...

, Alifanov and Saveliev redescribed the braincase noting that ''Bissektipelta'' had a well-developed olfaction, poor hearing and eyesight, good taste sensitivity, omnivorous diet and the unusual ability for filter-feeding. Also, the brain structure of ''Bissektipelta'' is rather primitive compared with other ankylosaur species. In 2020, Ivan Kuzmin and colleagues described and examined the braincase specimens of ''Bissektipelta'' in extensive detail. They performed a 3D reconstruction of the endocast of the brain cavity using

CT scans A computed tomography scan (CT scan), formerly called computed axial tomography scan (CAT scan), is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers or ...

and they revealed that a considerable part of the brain of ''Bissektipelta'' was occupied by

olfactory bulbs The olfactory bulb (Latin: ''bulbus olfactorius'') is a grey matter, neural structure of the vertebrate forebrain involved in olfaction, the sense of odor, smell. It sends olfactory information to be further processed in the amygdala, the orbitof ...

, confirming that ''Bissektipelta'' had an extremely developed

sense of smell The sense of smell, or olfaction, is the special sense through which smells (or odors) are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste. In humans, it ...

. The numerous small vascular canals around the skull roof, the lateral wall of the brain case and cranial vessels form a complex network around the brain which allowed the redistribution of the blood flow and physiological mechanisms for heat exchange in order to cool-down the brain and maintain optimal temperatures. In addition, the length of the cochlear ducts in the

inner ear The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the ...

suggests that ''Bissektipelta'', and many other ankylosaurs, were adapted for

low frequency Low frequency (LF) is the ITU designation for radio frequencies (RF) in the range of 30–300 kHz. Since its wavelengths range from 10–1 km, respectively, it is also known as the kilometre band or kilometre waves. LF radio waves ...

-hearing within 100 Hz and 3000 Hz. The elongated cochlear ducts in the more advanced ankylosaurines seem to indicate that these traits were adapted for enhanced hearing at lower frequencies.

References

{{Taxonbar, from=Q138923 Ankylosauridae Dinosaur genera Turonian dinosaurs Fossil taxa described in 2004 Bissekty Formation Dinosaurs of Uzbekistan

History of discovery

Description

Classification

Paleobiology

See also

References