©Verein zur Förderung der Paläontologie am Institut für Paläontologie, Geozentrum Wien Beitr. Paläont., 31:397-408, Wien 2009 The Late Miocene Mammal Faunas of the Mytilinii Basin, Samos Island, Greece: New Collection 16. Biochronology by George D. Koufos, Dimitris S. Kostopoulos & Theodora D. Vlachou*) K o u f o s , G.D., K o s t o p o u l o s , D.S. & V l a c h o u , Th.D. 2009. The Late Miocene Mammal Faunas of the Mytilinii Basin, Samos Island, Greece: New Collection. 16. Biochronology. — Beitr. Palaont., 31:397-408, Wien. Abstract Zuordnung der Säugetierfunde von Samos für lange Zeit. Zwei Interpretationen sind bekannt: bei der ersten handelt The limited correlation of the old collections to the fos- es sich um die Möglichkeit zweier Faunenvergesellschaf­ siliferous sites and to the local stratigraphy prevented safe tungen und die andere wäre eine homogene, isochrone dating of the Samos mammal fauna for a long time. Two Fauna. Neu aufgesammeltes Material und die detaillierte main approaches are known: that supporting the presence Studie dazu erlauben eine Trennung in drei aufeinander of two faunal assemblages and that of a single homogene­ folgende Faunenhorizonte (MLN, MYT, MTL), die vom ous and isochronous fauna. The collected new material, obersten Frühturolium bis zum späten Mittelturolium and its detailed study and comparison allow the separation reichen. Die Aufarbeitung der alten Sammlungen mit der of three chronologically succeeding faunal assemblages lokalen Stratigraphie und der Vergleich mit den Neufun­ MLN, MYT, M TL, ranging from the uppermost early den, sowie die Miteinbeziehung der magnetostratigraphi­ Turolian to late middle Turolian. The updated correla­ schen Ergebnisse der fossilen Mytilinii Formation führte tion of the old collections with the local stratigraphy and zu einer präzisen Datierung aller Fundstellen: a. Q5-? their comparison with the new collection, as well as the Limitzis, unterstes MN13, 6.9-6.7 Ma; b. Q l, QA, S3,4, magnetostratigraphic study of the fossiliferous Mytilinii Adrianos, M TL, MN12, ~7.1 Ma; c. Q3, S2,3, Potamies, Fm allow the precise dating of all fossil sites: a. Q5-? MYT, MN 12, ~7.3 Ma; d. Q2, Stefano, MLN, unterstes Limitzis, lowermost MN 13, 6.9-6.7 My; b. Ql, QA, MN12, ~7.5 Ma; e. Qx, Vryssoula, upper part of M N ll, S3,4, Adrianos, MTL, MN 12, ~7.1 My; c. Q3, S2,3, 8.0-7.6 Ma. Die Kombination der alten und neuen Daten Potamies, MYT, MN 12, ~7.3 My; d. Q2, Stefano, MLN, der turolischen Säugetierfundstelle von Samos erlaubt eine lowermost MN 12, ~7.5 My; e. Qx, Vryssoula, upper part Aufstellung von vier Evolutionsstadien und verwirft damit of MN 11, 8.0-7.6 My. The combination of old and new den alten „single fauna“-Ansatz. data concerning the Samos Turolian mammal faunas implies the establishment of four stages of evolution and Schlüsselworte: Obermiozän, Samos, Griechenland, refutes the “single fauna” approach. Säugetiere, Chronologie. Keywords: Late Miocene, Samos, Greece, Mammalia, Chronology. 1. Introduction The Late Miocene fossiliferous deposits of Samos Island, Zusammenfassung Greece, have been known since the second half of the 19th century, when Forsyth-Major discovered them and Die eingeschränkte Korrelation der alten Aufsammlun­ collected the first fossils. Then afterwards, several scien­ gen mit den Fossilfundstellen einerseits und der lokalen tists, as well as fossil collectors and dealers visited Samos Stratigraphie andrerseits verhinderte eine sichere zeitliche and gathered fossils for various museums and institutions (K o u f o s , this volume-a). There is a great number of pub­ lications concerning the Samos fauna, referreing either to Prof. George D. K o u f o s , Dr. Dimitris S. K o s t o p o u l o s 6c vertebrate paleontology or to chronology(M a j o r , 1888, MSc. Theodora D. V l a c h o u , Aristotle University of Thes­ 1891, 1894; A n d r e w s , 1896; S c h l o s s e r , 1899, 1906; saloniki, Department of Geology, Laboratory of Geology 8c O s b o r n , 1898; S t u d e r , 1911; A n d r e e , 1926; B r o w n , Paleontology, 54124 Thessaloniki, Greece, e-mail: koufos@ 1927; C o l b e r t , 1941; W e h r l i , 1941; v a n C o u v e r i n g & geo.auth.gr, [email protected]; [email protected] M i l l e r , 1971; G e n t r y , 1971; S o n d a a r , 1971; H e i s s ig , ©Verein zur Förderung der Paläontologie am Institut für Paläontologie, Geozentrum Wien 398 Beitr. Palaont., 31, Wien, 2009 1975; M e i s s n e r , 1979; B l a c k et al., 1980; S o l o u n i a s , Q l-6 = Quarryl-6, Samos, Greece 1981; K o u f o s S c M e l e n t i s , 1982,1984; W e i d m a n n et Qx = Quarry x, Samos, Greece al., 1984; S e n & V a l e t ; 1986; B e r n o r et al., 1996; and S = Stefano, Samos, Greece literature cited in these articles). In these studies, a great A = Adriano, Samos, greece number of fossils has been described, numerous species S2-4 = Solounias collection from Samos, Greece established and several opinions about the age of the Samos L = Limitzis site, Samos, Greece fauna have been proposed. Nevertheless, the absence of G = German quarries, Samos, Greece accurate locality descriptions from the old collections and the uncertainties about the local stratigraphy continued to plague biostratigraphic and age determinations and 2. Historical Overview left vague taxonomic definitions. Exceptions are Forsyth- Major’s collection in Lausanne (MGL) and B. Brown’s The Samos vertebrate fauna was considered equivalent collection at AM N H . Forsyth-Major marked the fossils to that of Pikermi for a long time as and was referred he collected as originating from ‘Stefano’, ‘Potamies’ and to as Pontian (Late Miocene/Early Pliocene), with the 'Adriano’, all referring to local place-names, whereas old-fashioned use of this term. A t first sight, the faunal Brown used a register code of seven “quarries’ (Qx, Ql-6), assemblages provided from these two Greek localities look corresponding to precise fossil sites. A first serious effort similar, but a thorough study indicates several differences. towards the relocation of the localities and their correlation The first serious efforts concerning age determination of with the various museum collections has been undertaken the Samos mammal fauna started in the 1970ies. At that by S o l o u n i a s (1981). The author combined personal field time v a n C o u v e r i n g & M i l l e r (1971), using Argon and laboratory observations with information from the Isotope Analysis, provided absolute radiometric datings available field books of B. Brown, the museum archives and for Samos Neogene volcanoclastic deposits, influencing the local people of Samos. But, as he realized, it is hard to various palaeontologists dealing with museum collec­ give a definite answer about the provenance of the entire tions to comment on the biochronological meaning of fossil collections as most of them were made by amateurs, the Samos fauna. sometimes including specimens purchased from villagers S o n d a a r (1971) studied the hipparion assemblage (mainly (K o u f o s , this volume-a). In the early 1970ies, absolute skulls and metapodials) of Samos, housed at AM NH, chronological methods were also used for the chronology and although he stated that “the phylogeny of the Samos of the Samos fauna, but again, due to the problems did Hipparion remains speculative” he realized that differ­ not result in a final solution as the correlation of the faunas ent Hipparion species from the various fossiliferous sites with the stratigraphic and sampling horizons remained might represent chronologically distinct assemblages questionable. (Table 1). The same author tried to check if there were W ith the aim to solve the Samos puzzle and its negative differences in other animal groups of the Samos fauna impact on European biochronology and mammalian sys- and he studied the aardwark Orycteropus gaudryi from the tematics, a team of palaeontologists from the Laboratory of Brown quarries (S o n d a a r , 1971). Comparing the length Geology and Palaeontology, University of Thessaloniki, led of the upper and lower molar row versus M 2 or m2, he by G.K., started a new series of excavations in 1993 (K o u ­ found that 0. gaudryi from Q5 is larger than that from f o s et al., 1997,2004). The main goal of this new campaign Q l-4 (S o n d a a r , 1971:figs. 4, 5). Thus, he supposed an was the relocation of the fossiliferous sites, their arrange­ age difference between the two faunas, accepting that the ment in a precise stratigraphic order, the collection of new size increase in this genus is an evolutionary trend, as the fossils and the dating of the faunas using biochronology recent 0. eriksoni is much bigger. G e n t r y (1971) arrived and magnetostratigraphy. The results of the first 12 years at a similar conclusion, studying “Pachy tragus” samples of this campaign are included in this volume. at AM N H from Q l-4 and Q5, whereas H e i s s ig (1975) distinguished four rhinocerotid assemblages on Samos and Abbreviations: later also indicated a time-distance between Q l-4 and Q5 AMNH = American Museum of Natural History, New York mammal faunas (Table 1).