| Ursus dolinensis Gran Dolina bear | |
|---|---|
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Carnivora |
| Family: | Ursidae |
| Genus: | Ursus |
| Species: | †U. dolinensis |
| Binomial name | |
| †Ursus dolinensis García and Arsuaga, 2001[1] | |
Ursus dolinensis (theGran Dolina bear) is an extinctmammaliancarnivore species of theUrsidae family. Itsfossilized remains were unearthed from the lowest layers of thestratigraphic sequence at the archaeological andpaleontological site ofGran Dolina (alsoTrinchera Dolina, a section of theTrinchera del Ferrocaril, lit. Railroad trenches), that is a part of theAtapuerca Mountains complex in theBurgos province, northernSpain.[2] The species was described by Nuria García andJuan Luis Arsuaga in a 2001 publication.[1] Skeletal fossils, mainly cranial fragments were recovered from the sediment units TD 3 and in particular TD 4 (TD =Trinchera Dolina). Presence in these layers suggests a chronology in between 900,000 and 780,000 years ago, which falls into theCalabrian stage of the earlyPleistocene.
The species has been described as the most primitive of allcave bears, and smaller than ablack bear. It has a slender body comparable to brown bears (Ursus arctos) and noticeably gracile features of thecranial andmandibular bones, that to some extent resemble those ofUrsus arctos andUrsus etruscus. Yet its overall morphological characteristics suggest a kinship with the line of thespeleoid bears.[3] Finally García and Arsuaga have concluded thatUrsus dolinensis "is the ancestor ofUrsus savini and to be very close to the common ancestor ofUrsus arctos".[1]
Thetype specimen of the Gran Dolina bear is a 255 mm (10.04 in) long leftmandible fragment with theacronymAta96-TDW4-E9-1, that retains thecanine, apremolar 4, amolar 2 and thealveoli of the premolars P1, P2 and P3. Severalparatype fossils include an incomplete rightmandible, a right lower molar, another lower molar, two jaw fragments, onephalanx bone of the foot and ametatarsal bone.[4] The discovery of a completeUrsus dolinensis skull during the 2012 excavation campaign and its analysis has according to the campaign's co-directorsEudald Carbonell, J.M. Bermúdez and J.L. Arsuaga helped to better determine the species'phylogenetic position.[5]
Nuria García described more of the species' specificmorphology in a comparison with theUntermaßfeld bear at the18th International Senckenberg Conference inWeimar in 2004. She confirms the primitivebrown bear-like features and highlights detailed dental traits shared by the two species, such as a "slender horizontalramus with straight vertical profile; all teeth sides converge towards themidline". The fourth lowerpremolars are massive and elliptical shaped with a prominentprotoconid.[a] The first lower molars are slender, the second lower molars are rectangular shaped and without medial constrictions. The fourth upper premolars are triangular shaped with simple high pointedcusps. The first upper molars are quadrangular to rectangular-shaped without central constriction and finally, the second upper molars are large without torsion.[7]