First record of the “small cave bear” in Bulgaria and the taxonomic status of bears of the Ursus savini Andrews – Ursus rossicus Borissiak group

Abstract

<jats:title>Abstract</jats:title> <jats:p>The discovery of rich, well preserved skull material in the latest Middle Pleistocene deposits of Mishin Kamik cave (N-W Bulgaria) presents an opportunity for a new analysis of the taxonomy and the phylogeny of the so called “small cave bears”. Not all the small cave bears known would have necessarily had a common origin, the size decrease could be related in a number of cases to a parallelism. The bear from Mishin Kamik is identical with “<jats:italic>Ursus rossicus</jats:italic>” B<jats:sc>orissiak</jats:sc> from Krasnodar (S. Russia). Both these samples must be referred to <jats:italic>U. savini</jats:italic> A<jats:sc>ndrews</jats:sc> from Bacton near Cromer (England). The specimens from Krasnodar and Mishin Kamik could be classified as <jats:italic>U. sa. rossicus</jats:italic>, a late form of the species. This species may have affinities with some Middle Pleistocene Siberian forms. <jats:italic>U. savini</jats:italic> is a small but very robust spelaeoid bear which is more advanced in a number of features than <jats:italic>U. deningeri</jats:italic>. In several aspects it attained the evolutional adaptations of the cave bears of the <jats:italic>U. spelaeus-U. ingressus</jats:italic> group and represents an independent lineage of spelaeoid bears. The Mishin Kamik population was adapted to a mosaic landscape of forests and open areas in hilly terrain. This bear had well developed grazing adaptations but had weak motor abilities.</jats:p>

Morphometry of upper cheek teeth of cave bears (Carnivora, Ursidae)

“…Another species, U. rossicus Borissiak, 1930 (including subspecies U. r. uralensis Vereshchagin, 1973), represents the smallest cave bear in the Middle and Late Pleistocene of eastern Europe, the Urals and western Siberia (Vereschagin & Baryshnikov ; Spassov et al . ). Baryshnikov () integrated it with U. savini Andrew, 1922, from the Middle Pleistocene of England (Forest Bed), whereas Spassov et al.…”

“…Baryshnikov () integrated it with U. savini Andrew, 1922, from the Middle Pleistocene of England (Forest Bed), whereas Spassov et al. () suggested recently distinguishing between U. savini (including rossicus ) and U. uralensis . According to mitochondrial evidence, U. rossicus occupies the basal position in the lineage of ‘ingressus’ (Stiller et al.…”

“…; Spassov et al. ), and several ‘early’ cave and brown bears from European localities dated to the early Middle Pleistocene. Those are scheduled to be considered separately later, after a review of the lower cheek teeth.…”

Morphometry of lower cheek teeth of cave bears (Carnivora, Ursidae) and general remarks on the dentition variability

“…The small cave bear, U. rossicus Borissiak, 1930 (including subspecies U. r. uralensis Vereshchagin, 1973), is represented in the Middle and Late Pleistocene of eastern Europe, the Urals, western Siberia, and Altai Mountains (Vereshchagin & Baryshnikov ; Spassov et al . ). Baryshnikov () integrates it with U. savini Andrew, 1922, from the Middle Pleistocene of England (Forest Bed), whereas Spassov et al .…”

“…Baryshnikov () integrates it with U. savini Andrew, 1922, from the Middle Pleistocene of England (Forest Bed), whereas Spassov et al . () recently suggested the distinction between U. savini (including rossicus ) and U. uralensis . According to mitochondrial evidence, it occupies the basal position in the lineage of ‘ingressus’ (Stiller et al .…”