First fossil darkling beetles assemblage (Coleoptera: Tenebrionidae) from the late Pleistocene of Buenos Aires, Argentina

RAMÍREZ, L.C., R. CARRARA, V.A. SILVESTRO Y G.E. FLORES

Mendoza

Simposio; IV International Tenebrionoidea Symposium; 2015

Late Pleistocene outcrops exposed inBuenos Aires province, Argentina, represent one of the most informative sourcesfor paleoecological studies on South American fauna and flora. Several proxieswere utilized for the study of pleistocene environmental conditions in thePampas, but only a few were based on paleoentomological data. The aim of thisstudy is to present the first record of three species of darkling beetles fromthe Late Pleistocene of Buenos Aires province, and to provide newpaleoenvironmental. The sediments containing fossil insects correspond to theGuerrero Member of the Luján Formation and where dated between 12,100 ± 100 14CBP and 13,400 ± 200 14C BP. During the extraction and concentration of fossilinsects we avoid the kerosene flotation and the sieving in order to maintainthe material suitable for radiocarbon dating andprevent breakage. We identified specimens of Nyctelia picipes (Billberg), Epipedonotacristallisata (Lacordaire) (Pimeliinae: Nycteliini) and Scotobius pilularius Germar(Tenebrioninae: Scotobiini). By analyzing theparticularenvironmental requirements of these species and the use of the MCR method, wecould infer values of temperature and other relevant climatic aspects. This association couldshow us the first pulses of post-glacial climate recovery and the replacementby the insect fauna that currently inhabit the area. This study is one of the firstapproaches to the quaternary paleoentomology of Argentina, and highlights thepotential of paleoentomological information, when evaluated in combination withprevious knowledge on global climate conditions after the last glacial maximum.