''Boreopricea'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of archosauromorph

reptile Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocepha ...

from the

Early Triassic The Early Triassic is the first of three epochs of the Triassic Period of the geologic timescale. It spans the time between 251.9 Ma and Ma (million years ago). Rocks from this epoch are collectively known as the Lower Triassic Series, which ...

arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

. It is known from a fairly complete skeleton discovered in a borehole on Kolguyev Island, though damage to the specimen and loss of certain bones has complicated study of the genus. ''Boreopricea'' shared many similarities with various other archosauromorphs, making its classification controversial. Various studies have considered it a close relative of '' Prolacerta'', tanystropheids, both, or neither. ''Boreopricea'' is unique among early archosauromorphs due to possessing contact between the

jugal The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species. Anatomy ...

and

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 ancestra ...

bones at the rear half of the skull.

History

''Boreopricea funerea'' was named and described by

Soviet The Union of Soviet Socialist Republics. (USSR), commonly known as the Soviet Union, was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 until Dissolution of the Soviet ...

paleontologist L. P. Tatarinov in 1978. It was primarily based on a fairly complete skull and skeleton collected in 1972 from a

borehole A borehole is a narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water ( drilled water well and tube well), other liquids (such as petr ...

at Kolguyev Island in the

Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five oceanic divisions. It spans an area of approximately and is the coldest of the world's oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, ...

. This

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, PIN 3708/1, included bones from most of the body, apart from the hip area, the tip of the snout, and various miscellaneous missing fragments. During Tatarinov's preparation, the bones were removed from a slab of rock and glued onto a large piece of

card stock Card stock, also called cover stock and pasteboard, is paper that is thicker and more durable than normal writing and printing paper, but thinner and more flexible than other forms of paperboard. Card stock is often used for business cards, ...

, positioned as they originally were in the rock. Tatarinov also mentioned a second specimen, PIN 3708/2, which was a portion of the snout. However, this specimen could not be found by subsequent studies and is now considered lost. The rock layers preserving ''Boreopricea'' fossils hail from the Ustmylian Gorizont, the most recent portion of the Vetlugian Supergorizont. The Ustmylian Gorizont is a regional biochronological zone which corresponds to the early

Olenekian In the geologic timescale, the Olenekian is an age (geology), age in the Early Triassic epoch (geology), epoch; in chronostratigraphy, it is a stage (stratigraphy), stage in the Lower Triassic series (stratigraphy), series. It spans the time betw ...

stage of the

. The genus was redescribed in 1997 by

University of Bristol The University of Bristol is a public university, public research university in Bristol, England. It received its royal charter in 1909, although it can trace its roots to a Merchant Venturers' school founded in 1595 and University College, Br ...

paleontologists

Michael Benton Michael James Benton (born 8 April 1956) is a British palaeontologist, and professor of vertebrate paleontology, vertebrate palaeontology in the School of Earth Sciences at the University of Bristol. His published work has mostly concentrated on ...

and Jackie Allen. They found that the specimen had been damaged during storage, as the skull was crushed and certain bones were missing (i.e. parts of the shoulder) or placed into odd positions (i.e. the hand). A plaster cast of the skull prior to its crushing was utilized for their description of the skull, but some areas, such as the

palate The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly sep ...

and braincase, eluded restudy. Further study of the specimen was undertaken as part of

Martin Ezcurra Martin may refer to: Places Antarctica * Martin Peninsula, Marie Byrd Land * Port Martin, Adelie Land * Point Martin, South Orkney Islands Europe * Martin, Croatia, a village * Martin, Slovakia, a city * Martín del Río, Aragón, Spain * M ...

's 2016 study on archosauromorph systematics.

Description

''Boreopricea'' would have had a sprawling posture and a generalized lizard-like body shape, though with a longer neck than most modern lizards. Benton & Allen (1997) estimated that ''Boreopricea'' had a total (snout tip to tail tip) length of 44.0 centimeters (17.3 inches), with a 2.9 cm (1.1 inch) skull and 23.0 cm (9.1 inch) inch tail, although these estimates are uncertain considering that the tip of the snout and large portions of the backbone are missing.

Skull

The skull had a broad snout, large

orbits In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an physical body, object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an satellite, artificia ...

(eye sockets), and two temporal fenestrae (holes at the back of the skull) like other

diapsid Diapsids ("two arches") are a clade of sauropsids, distinguished from more primitive eureptiles by the presence of two holes, known as temporal fenestrae, in each side of their skulls. The earliest traditionally identified diapsids, the araeosc ...

reptiles. Bones which lie at the top edge of the head, such as the

nasal Nasal is an adjective referring to the nose, part of human or animal anatomy. It may also be shorthand for the following uses in combination: * With reference to the human nose: ** Nasal administration, a method of pharmaceutical drug delivery * ...

and

frontal bone In the human skull, the frontal bone or sincipital bone is an unpaired bone which consists of two portions.'' Gray's Anatomy'' (1918) These are the vertically oriented squamous part, and the horizontally oriented orbital part, making up the bo ...

s, were rectangular. The

parietal bone The parietal bones ( ) are two bones in the skull which, when joined at a fibrous joint known as a cranial suture, form the sides and roof of the neurocranium. In humans, each bone is roughly quadrilateral in form, and has two surfaces, four bord ...

s are incomplete, but preserved portions contact the frontals along a straight edge without a parietal foramen (a hole in the skull, present in many reptiles, which houses the

pineal gland The pineal gland (also known as the pineal body or epiphysis cerebri) is a small endocrine gland in the brain of most vertebrates. It produces melatonin, a serotonin-derived hormone, which modulates sleep, sleep patterns following the diurnal c ...

). The

(cheek bone) was unusually shaped. It lacked a posterior process (lower rear prong), which meant that the lower temporal fenestra was open from below. Conversely, the ascending process (upper rear prong) was elongated, stretching above the lower temporal fenestra to contact the

squamosal bone 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 ...

at the rear of the skull. This jugal-squamosal contact (unique to ''Boreopricea'' among early archosauromorphs) effectively barricades the

postorbital bone The ''postorbital'' is one of the bones in vertebrate skulls which forms a portion of the dermal skull roof and, sometimes, a ring about the orbit. Generally, it is located behind the postfrontal and posteriorly to the orbital fenestra. In some ...

from the edge of the lower temporal fenestra. The lower jaw was long and slender. Teeth, when preserved, were conical, sharply pointed, and slightly curved.

Postcranial skeleton

The neck was somewhat elongated. A sequence of five cervical (neck) vertebrae were preserved, probably the third to seventh vertebrae in the backbone. They were longer and narrower towards the skull and shorter and wider towards the shoulder. The later cervical and dorsal (torso) vertebrae had two rib facets on each side: a large, outwards-projecting facet which was triangular in cross section, and a smaller, circular facet which barely projects at all. The upwards-projecting neural spines of the vertebrae were low. Cervicals had narrow neural spines while dorsals had neural spines which gradually expanded into teardrop-shaped structures when seen from above. These expansions on the neural spines have been termed mammillary processes. The caudal (tail) vertebrae were numerous; they were broader towards the base of the tail and much thinner towards the tip. The

scapula The scapula (: scapulae or scapulas), also known as the shoulder blade, is the bone that connects the humerus (upper arm bone) with the clavicle (collar bone). Like their connected bones, the scapulae are paired, with each scapula on either side ...

(shoulder blade) was very thin when seen head-on but large and boxy when seen from the side. Other shoulder bones, including a bony sternum, were described by Tatarinov (1978) but are now lost. The

humerus The humerus (; : humeri) 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 (bone), radius and ulna, and consists of three sections. The humeral upper extrem ...

(upper arm bone) had a shape like a heavily twisted hourglass, with the long axis of the portion near the shoulder offset at a right angle from that of the portion near the elbow. The

ulna The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...

and

radius In classical geometry, a radius (: radii or radiuses) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The radius of a regular polygon is th ...

(lower arm bones) were thin, curved rods like those of most other reptiles. Metacarpal III (the third bone of the hand) was as long as if not longer than metacarpal IV (the fourth bone of the hand), as with tanystropheids. Hindlimb bones are overall fairly typical in structure, although the

femur The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg. The Femo ...

(thigh bone) was broader than in most reptiles. The ankle was formed by four tightly-connected bones: the centrale,

astragalus Astragalus may refer to: * ''Astragalus'' (plant), a large genus of herbs and small shrubs *Astragalus (bone) The talus (; Latin for ankle or ankle bone; : tali), talus bone, astragalus (), or ankle bone is one of the group of foot bones known ...

calcaneum In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel; : calcanei or calcanea) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is t ...

, and distal tarsal IV. Although the astragalus and calcaneum were the most prominent bones in the ankle, all of the ankle bones were similar in size. ''Boreopricea'' also lacked a hole along the contact between the astragalus and calcaneum and the second

phalanx The phalanx (: phalanxes or phalanges) was a rectangular mass military formation, usually composed entirely of heavy infantry armed with spears, pikes, sarissas, or similar polearms tightly packed together. The term is particularly used t ...

(toe bone) of the fifth toe was long, both traits shared by tanystropheids. Metatarsal V (the fifth bone of the foot) was hook-shaped, as with various other archosauromorphs.

Classification

When first described in 1978, ''Boreopricea'' was considered to be a "prolacertiform" reptile, meaning that its closest relatives were believed to be other long-necked lizard-like creatures such as '' Prolacerta'' and '' Macrocnemus''. At this time, it was uncertain whether "prolacertiforms" were truly ancestral to modern

lizard Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...

s, or alternatively closer to

archosaur Archosauria () or archosaurs () is a clade of diapsid sauropsid tetrapods, with birds and crocodilians being the only extant taxon, extant representatives. Although broadly classified as reptiles, which traditionally exclude birds, the cladistics ...

s such as

crocodilia Crocodilia () is an order of semiaquatic, predatory reptiles that are known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorph pseudosuchia ...

ns and

dinosaur 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 ...

s. In the 1980s,

cladistics Cladistics ( ; from Ancient Greek 'branch') is an approach to Taxonomy (biology), biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesiz ...

helped to clarify some aspects of reptile classification, and analyses by

Jacques Gauthier Jacques Armand Gauthier (born June 7, 1948, in New York City) is an American vertebrate paleontologist, comparative morphologist, and systematist, and one of the founders of the use of cladistics in biology. Life and career Gauthier is the ...

, and Susan Evans found substantial evidence that "prolacertiforms" were

archosauromorphs Archosauromorpha (Greek language, Greek for "ruling lizard forms") is a clade of diapsid reptiles containing all reptiles more closely related to archosaurs (such as crocodilians and dinosaurs, including birds) than to Lepidosauria, lepidosaurs ( ...

(closer to archosaurs) rather than lepidosauromorphs (closer to lizards). Some of these analyses featured or mentioned ''Boreopricea''. Benton (1985) noted that ''Boreopricea'' was probably a prolacertid, but differed from ''Prolacerta'' due to the shape of its

and

bones. Evans (1988) placed ''Boreopricea'' as an intermediate branch between ''Prolacerta'', which was closer to the base of the "prolacertiform" group, and ''Macrocnemus'', which was closer to the most derived and bizarre "prolacertiforms", the tanystropheids. The classification of ''Boreopricea'' and "prolacertiforms" in general was given further scrutiny in 1997. Benton & Allen's redescription of the genus involved a phylogenetic analysis which found that ''Boreopricea'' was the

sister taxon 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 ...

to ''Prolacerta'', at least when superfluous and unstable data was cleared. ''Macrocnemus'' was not found to be close to either taxon; instead it was placed closer to the tanystropheids. Nour-Eddine Jalil performed a very similar study that year, as part of his description of the African "prolacertiform" ''

Jesairosaurus ''Jesairosaurus'' is an extinct genus of early archosauromorph reptile known from the Illizi Province of Algeria. It is known from a single species, ''Jesairosaurus lehmani''. Although a potential relative of the long-necked tanystropheids, thi ...

''. In contrast to Benton & Allen, Jalil's study placed ''Boreopricea'' deep within Tanystropheidae and unrelated to ''Prolacerta''. Some traits of ''Boreopricea'', such as a reduced posterior process of the jugal, were shared by both ''Prolacerta'' and tanystropheids. ''Boreopricea'' shared certain adaptations of the hands and feet with only tanystropheids, yet the shape of its scapula was closer to that of ''Prolacerta''. A landmark study by David Dilkes in 1998 found that ''Prolacerta'' was more closely related to

archosauriforms Archosauriformes (Greek for 'ruling lizards', and Latin for 'form') is a clade of diapsid reptiles encompassing archosaurs and some of their close relatives. It was defined by Jacques Gauthier (1994) as the clade stemming from the last common anc ...

rather than tanystropheids, dissolving the concept of a

monophyletic In biological cladistics for the classification of organisms, monophyly is the condition of a taxonomic grouping being a clade – that is, a grouping of organisms which meets these criteria: # the grouping contains its own most recent co ...

"Prolacertiformes" (i.e. a group where ''Prolacerta'' and tanystropheids had a common ancestor to the exception of archosaurs). ''Boreopricea'' would not be analyzed under this new framework until 2016, when it was restudied by

. Ezcurra did not consider ''Boreopricea'' close to tanystropheids, instead he found that it was an archosauriform relative, nearly as close as ''Prolacerta''. Some features visible in ''Boreopricea'' which justify this placement include the presence of mammillary processes and a heavily twisted humerus. Ezcurra also named a new group, Crocopoda, which includes all archosauromorphs closer to archosaurs than to tanystropheids. ''Boreopricea'' was part of this new grouping, which also included

rhynchosaur Rhynchosaurs are a group of extinct herbivorous Triassic archosauromorph reptiles, belonging to the order Rhynchosauria. Members of the group are distinguished by their triangular skulls and elongated, beak like premaxillary bones. Rhynchosaurs ...

s, allokotosaurs,

, and various other archosauriform-like reptiles, such as ''Prolacerta''. The following cladogram is based on Ezcurra's 2016 study. A 2017 study by Adam Pritchard &

Sterling Nesbitt Sterling Nesbitt (born March 25, 1982, in Mesa, Arizona) is an American paleontologist best known for his work on the origin and early evolutionary patterns of archosaurs. He is currently an associate professor at Virginia Tech in the Departme ...

slightly shifted the position of ''Boreopricea'', placing it closer to allokotosaurs rather than ''Prolacerta'' and archosauriforms.

Paleoecology

Ustmylian (or Ustmylskian) layers of Russian

biostratigraphy 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 Biology ...

record a lakeside environment filled with animals recovering and diversifying after the Permian-Triassic extinction event, the greatest mass extinction in the history of the earth. The most common fossils at this time and place were freshwater amphibians such as '' Wetlugasaurus malachovi'', '' Vladlenosaurus alexeyevi'', '' Vyborosaurus mirus'', and '' Angusaurus''. On land, the small omnivore niche was filled by a diverse assortment of endemic procolophonids, including '' Timanophon raridentatus'', '' Orenburgia bruma'', and '' Lestanshoria massiva''. The large predator niche was probably filled by early

such as '' Chasmatosuchus magnus'' and '' Tsylmosuchus jakovlevi''. These layers also preserved fossils of '' Scharschengia'', which may be one of the earliest

rhynchocephalia Rhynchocephalia (; ) is an order of lizard-like reptiles that includes only one living species, the tuatara (''Sphenodon punctatus'') of New Zealand. Despite its current lack of diversity, during the Mesozoic rhynchocephalians were a speciose g ...

ns (

tuatara The tuatara (''Sphenodon punctatus'') is a species of reptile endemic to New Zealand. Despite its close resemblance to lizards, it is actually the only extant member of a distinct lineage, the previously highly diverse order Rhynchocephal ...

relatives). ''Boreopricea funerea'' probably filled a small carnivore niche alongside mammal-like

therocephalia Therocephalia is an extinct clade of therapsids (mammals and their close extinct relatives) from the Permian and Triassic periods. The therocephalians ("beast-heads") are named after their large skulls, which, along with the structure of their te ...

ns as well as '' Microcnemus efremovi'', a reptile which was similar to and probably closely related to it.

References

{{Taxonbar, from=Q62959066 Archosauromorpha Prehistoric reptile genera Olenekian genera Early Triassic reptiles of Europe Triassic Russia Fossils of Russia Fossil taxa described in 1978