Beitr. Paläont., 31:157–187, Wien 2009 The Late Miocene Mammal Faunas of the Mytilinii Basin, Samos Island, Greece: New Collection 9. Rhinocerotidae by Ioannis X. Giaourtsakis*) Giaourtsakis, I.X., 2009. The Late Miocene Mammal Faunas of the Mytilinii Basin, Samos Island, Greece: New Collection. 9. Rhinocerotidae. — Beitr. Paläont., 31:157–187, Wien. Abstract Zusammenfassung The recent paleontological expeditions to the late Miocene Die jüngsten paläontologischen Forschungen in den fossiliferous localities of the Mytilinii Basin on Samos obermiozänen Fossilfundstellen des Mytilinii Beckens Island, Greece, have unearthed numerous rhinocerotid (Samos, Griechenland), haben zahlreiche Nashornreste remains that represent two species of horned rhinocer- erbracht, die zwei verschiedene horntragende Nashorn- oses, “Diceros” neumayri (Osborn, 1900) and Dihoplus arten beinhalten: “Diceros” neumayri (Osborn, 1900) und pikermiensis (Toula, 1906). The morphological differ- Dihoplus pikermiensis (Toula, 1906). Die morphologischen ences between the two species are discussed. The absence Unterschiede zwischen den zwei Arten werden bespro- of the hornless rhinoceros Chilotherium in our sample, chen. Das Fehlen des hornlosen Nashorns Chilotherium, which is known from previous Samos collections, is at- das aus früheren Ausgrabungen auf Samos bekannt ist, tributed to the limited material, particularly from the hängt möglicherweise mit dem begrenzten Fundmaterial stratigraphically older localities of Mytilinii-3 (MYT) zusammen, insbesondere aus den stratigraphisch älteren and Mytilinii-4 (MLN) of the Potamies ravine. In the Fundstellen Mytilinii-3 (MYT) und Mytilinii-4 (MLN) well-sampled localities of the younger Mytilinii-1 (MTL) der Potamies Schlucht. In den fossilreichen und strati- faunal assemblage of the Adrianos ravine, a significant graphisch jüngeren Fundstellen Mytilinii-1 (MTL) der interspecific dominance of Diceros“ ” neumayri over Diho- Andrianos Schlucht ist eine klare interspezifische Do- plus pikermiensis has been documented. The comparison of minanz von “Diceros” neumayri über Dihoplus pikermiensis the Samos rhinocerotids with other Turolian localities in dokumentiert worden. Der Vergleich der Nashornfauna Continental Greece and Western Asia indicates a closer von Samos mit anderen turolischen Fundstellen aus dem resemblance to the Asian ones, in particular from Ana- kontinentalen Griechenland und aus West-Asien zeigt tolia. The marked differences in the relative distribution eine stärkere Ähnlichkeit mit den asiatischen Fundstel- of rhinocerotid taxa among the Turolian localities of the len, insbesondere jenen aus Anatolien. Die markanten Eastern Mediterranean and adjacent regions are related Unterschiede in der relativen Verteilung der verschiedenen to environmentally-controlled provincial differences and Nashornarten in den turolischen Fundstellen im östlichen suggest the expansion of more open and arid habitats on Mittelmeerraum und in den benachbarten Regionen Samos and in Anatolia compared to Continental Greece hängen mit klimatischen provinziellen Unterschieden during this period of time. zusammen. Sie deuten die Verbreitung von offeneren und trockeneren Lebensräumen auf Samos und in Anatolien Keywords: Turolian, Samos, Greece, Mammalia, Peris- während des Turoliums an, im Vergleich zu den Fundstel- sodactyla, Rhinocerotidae, Systematics. len des kontinentalen Griechenlands. Schlüsselwörter: Turolium, Samos, Griechenland, Mam- malia, Perissodactyla, Rhinocerotidae, Systematik. *) Dipl.-Geol. Ioannis X. Giaourtsakis, Ludwig-Maximilians- 1. Introduction University of Munich, Department of Geo- and Environmen- tal Sciences, Section of Paleontology. Richard-Wagner-Str. The presence of fossil mammals on Samos Island has 10, D-80333 Munich, Germany. e-mail: i.giaourtsakis@lrz. been known since early historical times, as indicated by uni-muenchen.de surviving ancient Greek myths and artifacts (Solounias 158 Beitr. Paläont., 31, Wien, 2009 & Mayor, 2004; Koufos, this volume). The first docu- skulls from Samos were depicted and briefly described mented rhinocerotid fossils from Samos were part of a in short accounts on the Samos fauna accumulated in small collection collected by local villagers that was sold to various Museums (Drevermann, 1930; Leonardi, 1947; Italian travelers sometime between 1852 and 1866. These Melentis, 1968; Piccoli et al., 1975; Lehmann, 1984), specimens were deposited at the Geological Institute of or in general works (Thenius, 1955; Viret, 1958). Ger- the University of Padova and were reported much later aads (1988) presented a significant study on the horned by Leonardi (1947) and Piccoli et al. (1975). The first rhinoceros species from Pikermi and Samos, establishing systematic excavations on Samos were conducted during reliable criteria for distinguishing the cranial and dental the years 1885-1889 by the English physician and natural- remains of “Diceros” neumayri and Dihoplus pikermiensis. ist C. I. Forsyth Major, who was inspired by the ancient Giaourtsakis et al. (2006) refined the morphological myths (Forsyth-Major, 1888, 1891, 1994). In the catalog differences of their mandibles and deciduous dentitions, of his major findings,Forsyth-Major (1894) attributed and discussed their relative distribution and interspecific several rhinocerotid specimens to Rhinoceros pachygnathus dominance in Pikermi and on Samos. (here “Diceros” neumayri), a well-known species at that time In the present study, we describe the rhinocerotid mate- from the renowned locality of Pikermi (Wagner, 1848; rial collected during the recent paleontological expedi- Gaudry, 1863). Following the impressive discoveries of tions on Samos that were conducted under the direction Forsyth Major, a great number of expeditions was carried of Prof. G.D. Koufos, under the auspices of the “K. and out on Samos by a variety of fossil dealers and scientists M. Zimalis Foundation” and the Aegean Museum of during the next decades, spreading the amply recovered Natural History (Koufos, this volume). The studied material to numerous museums and institutional collec- material was unearthed from three localities, Mytilinii-4 tions across Europe and the USA (Solounias, 1981a, b; (MLN), Mytilinii-3 (MYT), and Mytilinii-1 (MTL). Koufos, this volume). The locality MLN is placed in the Potamies ravine and is The first detailed studies on the Samos rhinoceroses were dated to early Turolian (uppermost MN 11) at ~7.5 Ma. undertaken by Weber (1904, 1905), who described and The locality MYT is situated in the Potamies ravine and illustrated a remarkably rich collection hosted at that is dated to early middle Turolian (early MN 12) at ~7.3 time at the Paleontological Museum of Munich. In his Ma. The locality MTL is located in Adrianos ravine and first contribution, Weber (1904) studied the remains consists of several fossiliferous sites; the rhinocerotids have of the horned rhinoceroses (subfamily Rhinocerotinae). been traced in the sites MTLA, MTLB, MTLD dated Apart from the dominant Rhinoceros pachygnathus (here to the uppermost middle Turolian (MN 12) at ~7.1 Ma. “Diceros” neumayri), Weber also recognized the presence Further, the specimens from the 1963 expedition by Prof. of a second horned rhinoceros species on Samos, which J.K. Melentis in Adrianos ravine (Melentis, 1968) are he referred to Rhinoceros schleiermacheri (here attributed to also included in the present study. Melentis’ excavation Dihoplus pikermiensis). In his second contribution, Weber site coincides with Mytilinii-1A (MTLA), but to avoid (1905) documented the presence of two additional horn- confusion, the specimens of this collection are referred to less rhinoceros species (subfamily Aceratherinae), which by the prefix PMMS before their code number (Koufos, he attributed to the new species Aceratherium schlosseri this volume). A detailed account on the geological and and Aceratherium samium. Later on, both hornless species stratigraphical setting of the different fossiliferous sites of were properly included by Ringström (1924) in his newly Samos is provided by Kostopoulos et al. (this volume) created genus Chilotherium. Unfortunately, the entire rhi- and Koufos et al. (this volume-a). nocerid material from Samos at Munich was destroyed by a heavy bombing during the Second World War. A second systematic study was undertaken by Andreé (1921), who 2. Material and Methods examined the Samos rhinocerotid collection at the Paleon- tological Museum of Münster. Andreé (1921) recognized The rhinocerotid material described in the present article the four species previously documented by Weber (1904, is stored in the collections of the Natural History Mu- 1905), and created two additional hornless rhinoceros spe- seum of the Aegean, Mytilinii, Samos (NHMA). Cranial cies, Aceratherium wegneri and Aceratherium angustifrons. and mandibular measurements follow Guérin (1980), However, their specific identity is doubtful. The rather including a few additional measurements. Anatomical well-preserved type cranium with associated mandible of conventions follow Getty (1975) and Baron (1999), also Aceratherium wegneri evidently belongs to Weber’s Chi- considering the recommendations of NAV (2005). Dental lotherium schlosseri, as first suggested by Heissig (1975a, measurements and terminology follow Peter (2002), but b). The incomplete and transversally compressed type width measurements include the mesial (Wm), as well as cranium of Aceratherium angustifrons may either belong the distal (Wd) width of each