Boreopricea is an extinct genus of archosauromorph reptile from the Early Triassic of arctic Russia.[1] 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,[1][2] tanystropheids,[3] both,[4] or neither.[5] Boreopricea is unique among early archosauromorphs due to possessing contact between the jugal and squamosal bones at the rear half of the skull.[1]
Boreopricea funerea was named and described by Soviet paleontologist L. P. Tatarinov in 1978. It was primarily based on a fairly complete skull and skeleton collected in 1972 from a borehole at Kolguyev Island in the Arctic Ocean. This holotype 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, 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.[1] 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 stage of the Early Triassic.[6][7]
The genus was redescribed in 1997 by University of Bristol paleontologists Michael Benton 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 and braincase, eluded restudy.[1] Further study of the specimen was undertaken as part of Martin Ezcurra's 2016 study on archosauromorph systematics.[2]
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.[1]
The skull had a broad snout, large orbits (eye sockets), and two temporal fenestrae (holes at the back of the skull) like other diapsid reptiles. Bones which lie at the top edge of the head, such as the nasal and frontal bones, were rectangular. The parietal bones 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 jugal (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 at the rear of the skull. This jugal-squamosal contact (unique to Boreopricea among early archosauromorphs) effectively barricades the postorbital bone 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.[1]