Varshets and Slivnitsa – new localities of Villafranchian vertebrate fauna from Bulgaria (taxonomic composition, biostratigraphy and climatochronology)

Abstract

Two recently discovered rich Bulgarian localities have been studied and described as localities of Villafranchian fauna - Varshets and Slivnitsa. They represent two faunistic complexes immediately succeeding one another in time. Varshets is a Late Pliocene locality. After its fauna it ought to be referred to the biochronological zone MNQ 17, that may be subdivided into two successive subzones. It seems that the fauna of this locality is earlier than that of the marker locality St.-Vallier. The fauna of Varshets numbers more than 100 taxa of vertebrates, including 18 species of Macromammalia. The faunistic complex presupposes a mosaic landscape of open spaces and forests or an open ("park") type of forests. After the climato-stratographic subdivision, the fauna falls at SCT12, or even more probably, at the beginning of SCT11. The locality of Slivnitsa refers to the the very end of the Pliocene and the Late Villafranchian. The fauna consisting of 19 species of Macromammalia too, times it to the beginning of the zone MNQ 18, which probably ought to be also divided into subzones – MNQ18a = Seneze Unit (Final Pliocene) and MNQ18b = Olivola Unit (probably Earliest Pleistocene). The time of this fauna corresponds to the intermediate cooling during the Beregovka warming that falls on the superclimatheme SCT10. The predominance of Bovidae, that are typical of the open spaces, indicates more aridic climate than Varshets. Slivnitsa and Seneze are the earliest localities where the first migration wave of Canis s.str. has appeared from the east. This wave having been spread in most regions of Europe at the beginning of the Pleistocene. It seems that Slivnitsa is also the earliest locality reflecting the appearance of the genus Panthera on the continent.

The Villafranchian Mammalia fauna and its investigation in Europe, on the Balkans and in Bulgaria

“…This event comes chronologically quite later than the time of appearance of C. etruscus s. str. Procamptoceras has already been found in MNQ17 (Duvemois & Guerin, 1989); the elaboration of Varshets revealed the fact, that Megalovis had also inhabited Europe yet in MNQ17 (Spassov, Cregut-Bonnoure, in preparation;Spassov, 1997). We have to note once again that SenezejSlivnitsa are still showing some features of Pliocene lo~alities: Pachycrocuta brevirostris has not yet appeared in Seneze, while Nyctereutes is still present there; the evolution stage of Microtinae of Slivnitsa corresponds to that of the Pliocene's end (V. Popov, Institute of Zoology, Sofia, personal communication).…”

“…Obviously, the geological methods of investigation are not able to reveal the climatic changes going on simultaneously with the corresponding change of the faunas' appearance during the Plio-Pleistocene transition. Considering this suggestion, one must put the beginning of the Late Villafranchian in the end of the Pliocene {Tchernov, Guerin, 1986;Spassov, 1997). We can conclude, further on, that the Neogene/Quaternary and the Middle/Late Villafranchian boundaries do not entirely conform with each other, although being united by reflecting climatic changes: the proper geological boundaries can be outlined as far as the natural-climatic changes are already well expressed.…”

“…Seneze, Slivnitsa) which seemingly belong to the Pliocene end (cf. Boeuf, 1997;Spassov, 1997), reveal a clear similarity between their mammalian megafauna and that of the beginning of Pleistocene. If not after the composition as a whole, this similarity could be traced at least after the general appearance of corresponding faunas.…”

“…This wave has been established in most places of Europe at the beginning of Pleistocene. Slivnitsa is, probably, also the oldest locality to demonstrate the invasion of the Panthera genus on the continent (Spassov, 1997).…”