Pleistocene fauna on Trlica hill near Pljevlja (Montenegro)

The town of Pljevlja and its beautiful natural scenery are of great scientific interest for both the concealed and recovered evidences of a turbulent history. Those ancient, millions of years old, are natural products in the form of different rocks and minerals, metallic and nonmetallic ores and coal, and the evidences of cultural or historical past are the witness of the life continuity from the Mesolithic to the present time. A period in the local natural history was, however, obscured until recently. It covers the beginning of the period of becomming cool on Northern part of the Earth.

Rocks formed in the Quaternary have been largely eroded, mainly reduced to alluvial deposits in river valleys or diluvial beds on mountain slopes. Fossil organisms in these rocks are very sporadic and few in number. On Trlica hill though, near Pljevlja, a small part of the history has been preserved: a cavern formed by karstic erosion in Triassic limestone is filled with Quaternary sediments bearing abundant bones and teeth of fossil mammals.

The cavern was found when the Pljevlja-Prijepolje road was built, but, unfortunetely, a large part of the fossil material was destroyed. The cavern locality was partly explored in 1988 and again in 1990.

Physical setting and importance of the locality

The Trlica locality on the namesake hill, lies 2.5 km from Pljevlja on the left side of the Pljevlja-Prijepolje road. Fossil fauna found in this locality is dated to upper Lower to lower Middle Pleistocene, the only locality of this age in Yugoslavia, which gives it a particular biostratigraphical importance for the Quaternary system of this country.

A principal characteristic of the fauna found on Trlica hill is the diversity of large mammals, artiodactyl and perissodactyl ungulates, and carnivores. So far thirteen mammal species have been identified, representing ten different families and five genera: Rodentia (rodents): Arvicolidae (voles) - Dolomys dalmatinus Kormos, Hystricidae (porcupines) - Hystrix sp.; Carnivora: Canidae (dogs) - Canis sp.; Ursidae (bears) - Ursus sp.; Hyaenidae (hyenas) – Pachycrocuta brevirostris Aymard; Proboscidae (proboscids): Elefantidae indet. (elephants), Perissodactyla (perissodactyl ungulates); Equidae (horses) – Equus stenonis Cocchi; Rhinocerotidae (rhinoceroses) – Dicerorhinus etruscus Falconer; Artiodactyla (artiodactyl ungulates); Cervidae (deers) - Megacerini indet. ? Cervus sp.; Bovidae (oxen) - Bison cf. schoetensacki Freudenberg; Megalovis sp., Caprinae indet.

The presence of rhinoceros of the perissodactyl ungulate mammals is significant because it had a relatively rapid evolution in the Quaternary and certain paleoecological sensitivity. Most abundant in this locality are representatives of artiodactyl ungulates, the ruminants. The largest ruminant found is Bison cf. schoetensacki Freudenberg, unknown in Jugoslavia. Also found on Trlica are remnants of two species of the Caprinae subfamily which includes sheep, goats and congenial animals. One of these is as big as the presentday sheep. The other is very big compared with members of the same subfamily, without a direct recent descendent, but resembling the musk ox in size and general appearance of the head. The latter belongs to the family Megalovis (giant sheep), characteristic of the earliest Quaternary, that was not found earlier in Yugoslavia.

Geological age of the fauna

The Quaternary age of the mammal fauna from Trlica is supported by the presence of Equus and Bison which mark the beginning of the Quaternary. The Lower Quaternary is also confirmed by the species existent in the Villafranchian, primarily a single Bovidae species - Megalovis sp. - known so far only from a Villafranchian locality, and the species that continued to exist in the Lower Pleistocene until the ?great Gnz/Mindel interglaciation, viz. Equus stenonis, Dicerorhinus etruscus Pachycrocuta brevirostris (Kurten, 1968). In contrast, the species Bison schoetensacki appeared in Europe after the Gnz/Mindel interglaciation (Gromova, 1965; Freudenberg, 1914) to which the only arvicolide found in this locality is associated.

The lower Quaternary mammal fauna of Montenegro and Serbia is almost unknown; there are not accurate stratigraphical data for the few found fossils. Pachycrocuta brevirostris, Megalovis sp., B.shoetensacki, D.dalmatinus and D.etruscus were not known among the fossil fauna of Yugoslavia.

The motif of the project

The Trlica locality is directly threatened by atmospheric precipitations, as some deposits with valuable fossil remains are yearly eroded. Unchecked, this trend will lead to the disappearance of this evidence of our ancient history.

This is the reason why it has been decided to resume excavation this summer, which will be headed by Dr. Vesna Dimitrijevic and with the cooperation of Jugoslav Zic and colleagues of the Museum of Natural History and Nature Conservation Institute of Podgorica. The continuation of the excavation is planned for the next summer. Fossil material will be assembled, treated, and given to the Museum of Natural History of Podgorica for its paleontological collection.

If the planned excavation proves successful, the National Committee of Geo-heritage Yugoslavia will insist on including the locality in one of its Inventory categories. The available information already qualifies it, like Prebreza in Serbia, as a site of national, or even Balkan, importance.

References:

Dimitrijevic V. 1990: Prvi rezultati istrazivanja sisarske faune iz Trlice kod Pljevalja.- XII kongres geologa Jugoslavije, knj. I stratigrafija, sedimentologija, paleontologija, Ohrid.
Dimitrijevic V. 1991: Otkrice, istrazivanje i znacaj fosilne faune sisara na brdu Trlica kod Pljevalja. - Ekoloski casopis «Biserka» br. 1., Pljevlja.

V. Dimitrijevic, J.Zic, D.Mijovic