AMQ abs Palombo SACCOM 177-180.pub Available online http://amq.aiqua.it ISSN (online): 2279-7335 Alpine and Mediterranean Quaternary, Vol. 31 (QUATERNARY: Past, Present, Future - AIQUA Conference, Florence, 13-14/06/2018), 177 - 180 TWENTY YEARS LATER: REFLECTIONS ON THE AURELIAN EUROPEAN LAND MAMMAL AGE Maria Rita Palombo IGAG-CNR, c/o Dipartimento di Scienze della Terra, Università di Roma “Sapienza”, Roma, Italy Corresponding author: M.R. Palombo ABSTRACT: In 1997, some Italian palaeontologists proposed a new biochronological assessment for selected Italian Late Pliocene- Quaternary terrestrial mammal, mollusc and ostracod species. In particular, they proposed a new Land Mammal Age (Aurelian LMA), emphasising the relevance of the taxonomical and functional turnover that characterised the post-Galerian fauna (“extinction of some Galerian forms” and the first appearance of “taxa which constitute the core of the modern mammal fauna”). During the following dec- ades, the discovery of several Middle Pleistocene European Local Faunal Assemblages (LFAs) led to a continuous increasing of data and knowledge on the taxonomical status and the chronological range of several large mammal taxa, and new radiometric/absolute dates and magnetostratigraphical information provided substantial evidence, for a new chronological assessment of a number of Euro- pean LFAs. This note aims to present a synthetic overview of the most significant new evidence and some reflections on the transition from the Galerian to the Aurelian ELMA, and the significance of the Aurelian as European Land Mammal Age. KEYWORDS: Biochronology, biochronological units, large mammals, middle Pleistocene 1. INTRODUCTION: THE FACT OF THE MATTER The Biochronological Units (BUs) known as Land Mammal Ages (North, NALMA, and South American, SALMA, European, ELMA, and Asian, ALMA) were initially developed in the first half of the last century in an attempt to chronologically order the North American Cenozoic mammalian assemblages (Wood et al., 1941). Since that time, LMAs have been largely, but diversely/ ambiguously used by palaeontologists, and are still loosely defined. The requirements they have to fulfil, indeed, have never been discussed in any stratigraphi- cal code (see Lindsay, 2003, pages 213, 220), and the criteria required to create a BU are vague and remain unaddressed. According to Tedford (1970, page 602), for instance, a BU (a biological entity equivalent to a discrete natural association of fossil species) could be regarded as non-overlapping and "ecologically adjusted groups of animals with specific geographical limits and chronological range", while Lindsay (2003, page 222) defined more explicitly a LMA as “a relatively short inter- val of geologic time that can be recognised and distin- guished from earlier and later such units (in a given region or province) by a characterizing assemblage of mammals”. The first/last historical appearance (FHA/LHA) (palaeobiological events inferred on the basis of the sum of known, palaeobiological data provided by the fossil record derived from strata from the focal geo- graphical region), the peculiar taxonomical composition and ecological structure of the mammalian fauna (which make a BU different from the earlier and later ones re- corded in the same geographical area), are the key factors to consider to correctly identify a BU, whichever its chronological range should be. The known lowest and highest stratigraphical occurrence of a taxon in a given geographical area (stratigraphical datum), how- ever, does not necessarily correspond to its first and last appearance in the time (palaeobiological datum). The finding of a taxon, regarded as a biological chrostrati- graphical marker of a BU (sensu Lindsay, 2003) in strati- graphical levels significantly older/younger than those previously providing its fossil record may, for instance, substantially change the chronological extent of the BU to which it belongs, without changing its theoretical defi- nition. This in turn implies a new assessment and defini- tion of the BUs directly preceding/succeeding in time the focal one. In addition, increasing palaeontological and stratigraphical data might allow to better discriminating bioevents, on the one hand highlighting, the gradual transition between successive BUs, but, on the other, blurring a clear identification of the BUs. As a result, any biochronological scheme, and the definition and temporal extension of a BU, even if dependable, are open to change because depending on the available data,. This note aims to present the main evidence sug- gesting to revise the definition of the Aurelian BU (as provided at the time it was proposed by Gliozzi et al., 1997) and its significance as ELMA, and some prelimi- nary reflections on the issues related to the transition from the Galerian to the Aurelian ELMA. A more exhaus- tive discussion will be provided elsewhere. 2. THE AURELIAN BIOCHRONOLOGICAL UNIT: A REAPPRAISAL The Aurelian BU was introduced in 1997 in the con- text of a new biochronological assessment proposed by a team of Italian palaeontologists for selected Italian Late Pliocene-Quaternary terrestrial mammal, mollusc and ostracod species (Gliozzi et al., 1997, page 372). The Italian researchers recommended the new Aurelian Land https://doi.org/10.26382/AIQUA.2018.AIQUAconference Mammal Age (LMA) for the late Middle-Late Pleisto- cene mammalian fauna, i.e. from Marine Isotopic Stage (MIS) 10 to MIS 2, emphasising the relevance of the taxonomical and functional turnover characterising the transition from the Galerian to the post-Galerian fauna (“extinction of some Galerian forms, such as the megacerine cervids of the Megaceroides (recte Praemegaceros) verticornis group, Megaloceros savini and the more archaic elaphine deer”, and the first ap- pearance of “taxa which constitute the core of the mod- ern mammal fauna”) (Gliozzi et al., 1997, page 372). The characterisation of the new LAM was mainly based on the taxonomical composition of some Italian local faunal assemblages (LFAs) found in “deposits, which date to the late Middle Pleistocene and the Late Pleisto- cene” (Gliozzi et al., 1997, page 372). The FHA of Canis lupus, Ursus spelaeus and Magaloceros giganteus (mentioned as regards to their FHA in the oldest Aurelian Faunal Unit) were the bio- events chosen by Gliozzi et al. (1997) to identify the beginning of the Aurelian BU, but what about the time of the FHA of these taxa in Europe? New evidence dates back the C. lupus presence to MIS 14(?) – MIS 13 (Galería GII, Atapuerca, Spain) (Rodriguez et al., 2011; Álvarez-Posada et al., 2018). A small wolf, Canis lupus lunellensis, was already reported from Lunel Viel (France), a site dating to about 400- 350 ka (Brugal and Boudadi-Maligne, 2011 and references therein), and the modern wolf is also recorded, together with M. gi- ganteus, during MIS 11 in some European LFAs, for instance, in Britain (Stewart, 2008 and references therein). The time of the lowest stratigraphical occur- rence in Europe of U. spelaeus cannot firmly be estab- lished due to some confusing taxonomical treatments of some specimens (most lacking sound taxonomical diag- nostic features), likely belonging to one or the other species of the cave bear lineage known in the Middle Pleistocene: Ursus deningeri and its putative descen- dant U. spelaeus. In Schreve’s opinion (Schreve, 2001, page 1694), for instance, in the “Swanscombe mammal assemblage-zone” (MIS 11) “the early Middle Pleisto- cene form Ursus deningeri Reichenau” was “superseded by the more advanced form Ursus spelaeus”. The Den- inger’ bear, conversely, has been reported even from significantly younger LFAs, such as Orgnac 3 levels 7-3 (France) (e.g. Sam, 2009). The available data, moreover, indicate that some among the large mammals commonly found in the Aurelian LFAs were already present either in the post- Jaramillo Early Pleistocene (e.g. Palaeoloxodon antiquus, Crocuta crocuta, Lynx pardinus, Sus scrofa), or in the early Middle Pleistocene (MIS 19 - MIS 12) (e.g. Ursus arctos, Ursus thibetanus, Vulpes vulpes, Cuon alpinus, Felis silvestris, Stephanorhinus hemi- toechus, Bos primigenius, Dama clactoniana, Bison priscus, Bos primigenius, maybe Rupicapra pyrenaica), or at least during MIS 11(e.g. Hippopotamus ex gr. H. amphibius, modern roe deer Capreolus capreolus, M. giganteus), suggesting to predate the beginning of the Aurelian BU (Fig.1, 2). Assuming that the hypothesis could be correct, the question arises about the time of the transition from the Galerian to the Aurelian BU. According to Gliozzi et al. (1997, page 372), the late Galerian fauna, to which only the Fontana Ranuccio F.U. was referred, “is characterised by the total disap- pearance of typical Villafranchian taxa with the excep- tion of Homotherium” and by the presence of “the red Fig. 1 - Chronological range of selected Middle and Late Pleistocene European Proboscideans, Primates, and Carnivora. 178 Palombo M.R. deer subspecies Cervus elaphus eostephanoceros. As regards to the “Villafranchian” large predators, new data indicate that the saber-toothed cat was still present during MIS 3 (Reumer et al., 2003), and Panthera gom- baszoegensis in deposits correlated to MIS 9 or MIS 10 (Marciszak, 2014). It is worth noting, that Fontana Ranuccio LFA (Anagni Basin, central Italy), regarded by Gliozzi et al. (1997) as one of the most representative late Galerian site and epitome of the homonymous F.U., was at that time dated to 0.458 Ma (MIS 12). The age of most of the European LFAs successively corre- lated to the Fontana Ranuccio LFA or ascribed to the homonymous F.U. fall in the chronological range of MIS 13 and MIS 12. Recently, Pereira et al. (2018) obtained a 40Ar/39Ar age of 408±10 ka for the archaeological level (unit FR4) of Fontana Ranuccio, roughly corresponding to MIS 11 climatic optimum, in some agreement with the fauna ecological structure. According to the new date, the LFA would fall in the extended chronological range of the Aurelian BU, together with other roughly coeval LFAs from the same geographic area already regarded as “Aurelian” (e.g. Isoletta, Lademagne). Al- though this fact could not substantially affect the defini- tion of the “late Galerian”, the question about the signifi- cance of C. e. eostephanoceros as a biological chros- tratigraphical marker remains unsolved. In the Gaudo San Nicola LFA, a site chronologically and geographi- cally close to Fontana Ranuccio, indeed, Sala et al. (2014) claimed the presence of the archaic Cervus eluphus acoronatus subspecies, considering C. e. eostephanoceros a young synonymous of the former. All in all, the available data evidence the gradual, progressive transition from a ELMA to the successive one during the late Early and Middle Pleistocene, as well as the complexity in properly detecting and defining such ELMAs. 3. REMARKS The sum of evidence highlights the gradual modifi- cation of the structure of the mammalian palaeocommu- nities, leading to the configuration of the Aurelian ones (e.g. Palombo, 2017), and, in turn, the difficulty to prop- erly define discrete LMAs succeeding each other during a short geological time. The original LMA concept, in- deed, implicitly implies a long persistence in time and a wide geographical extent for each unit, given that the mean duration of a large mammal Cenozoic species is about 3 Ma (see Prothero, 2014 as regards to the North American mammals). Therefore, the shorter the time slice is, the more difficult to properly define a LMA could be. Any analysis performed on short geological time periods, for instance, may sometimes force researchers to consider taxa at a low taxonomical rank, thereby in- creasing the risk of disagreements in the taxonomies applied by the authors. Additional drawbacks may con- cern the need of a particularly detailed chronology, in contrast with a proportionally low number of LFAs with firm chronological constrains. An alternative approach may be to focus more on the detection of "ecologically adjusted groups of animals with specific geographical limits and chronological range" than merely on FHA/LHA bioevents. Following this line of reasoning, taking into account: i) the climatic and environmental changes (e.g. the increase in sum- mer temperatures, and average forest expansion during interglacial phases) that occurred since MIS 11; ii) its peculiarity with respect to the previous Middle Pleisto- cene interglacials (higher level than present-day sea related to the collapse of Greenland and West Antarc- tica ice sheets, greenhouse gas-driven climate warming pattern of insolation variability matching the Holocene one) (e.g. Oliveira et al., 2016 and references therein), iii) the number of FHA reported at that time (Figs. 1, 2), 179 Reflections on the Aurelian ELMA Fig. 2 - Chronological range of selected Middle and Late Pleistocene European Perissodactyla and Cetartiodactyla. iv) the Functional Diversity characterising the large mammal fauna since MIS 11 (Palombo, 2016), the hy- pothesis to chronologically extend the Aurelian BU to include MIS 11 seems to be the most reasonable. As a result, the definition and biochronological significance of the “late Galerian” fauna, which according to Gliozzi et al. (1997) only includes the “Fontana Ranuccio Faunal Unit”, has to be reconsidered. REFERENCES Álvarez-Posada C., Parés J.M., Cuenca-Bescós G., Van der Made J., Rosell J., Bermúdez de Castro J.M.B., Carbonell E. (2018) - A post-Jaramillo age for the artefact-bearing layer TD4 (Gran Dolina, Atapuerca): New paleomagnetic evidence. Qua- ternary Geochronology, 45, 1-8. Brugal J.P., Boudadi-Maligne M. (2011) - Quaternary small to large canids in Europe: taxonomic status and biochronological contribution. Quaternary International, 243(1),171-182. García-Medrano P., Cáceres I., Ollé A., Carbonell, E. (2017) - The occupational pattern of the Galería site (Atapuerca, Spain): A technological perspec- tive. Quaternary International, 433, pp. 363-378. Gliozzi E., Abbazi L., Ambrosetti P., Argenti, P., Azzaroli A., Caloi L., Capasso Barbato L., Di Stefano G., Esu D., Ficcarelli G., Girotti O., Kotsakis T., Masini F., Mazza P., Mezzabotta C., Palombo M.R., Petronio C., Rook L., Sala B., Sardella R., Zanalda E., Torre D. (1997) - Biochronology of selected Mammals, Molluscs, Ostracods from the Middle Pliocene to the Late Pleistocene in Italy. The state of the art. Rivista Italiana di Paleontolo- gia e Stratigrafia, 103 (3), 369-388. Lindsay E.H. (2003) - Chapter 10: Chronostratigraphy, Biochronology, Datum Events, Land Mammal Ages, Stage of Evolution, and Appearance Event Ordination. Bulletin of the American Museum of Natural History, 212-230. Marciszak A. (2014) - Presence of Panthera gombaszoegensis (Kretzoi, 1938) in the late Mid- dle Pleistocene of Biśnik Cave, Poland, with an overview of Eurasian jaguar size variability. Qua- ternary International, 326, 105-113. Oliveira D., Desprat S., Rodrigues T., Naughton F., Hodell D., Trigo R., Rufino M., Lopes C., Abrantes F., Goni, M.F.S. (2016) - The complexity of millen- nial-scale variability in southwestern Europe dur- ing MIS 11. Quaternary Research, 86(3), 373-387. Palombo M.R. (2017) - Discrete dispersal bioevents of large mammals in Southern Europe in the post- Olduvai Early Pleistocene: A critical overview. Quaternary International, 431, 3-19. Palombo M.R. (2016) - To what extent could functional diversity be a useful tool in inferring ecosystem responses to past climate changes? Quaternary International, 413, 15-31. Pereira A., Nomade S., Moncel M.H., Voinchet P., Bahain J.J., Biddittu I., Falguères C., Giaccio B., Manzi G., Parenti F., Scardia G. (2018) - Inte- grated geochronology of Acheulian sites from the southern Latium (central Italy): Insights on human- environment interaction and the technological innovations during the MIS 11-MIS 10 period. Quaternary Science Reviews, 187, 112-129. Prothero D.R. (2014) - Species longevity in North American fossil mammals. Integrative zoology, 9 (4), 383-393. Reumer J.W., Rook L., Van Der Borg K., Post K., Mol D., De Vos J. (2003) - Late Pleistocene survival of the saber-toothed cat Homotherium in Northwest- ern Europe. Journal of Vertebrate Paleontology, 23(1), 260-262. Sala B. BoulbesN., Moigne A-M., Thun Hohenstein U. (2014) - In: Muttillo B., Lembo G. Peretto, C. (Eds), L'insediamento a bifacciali di Guado San Nicola, Monteroduni, Molise, Italia. Annali Univ Ferrara, Museologia Scient. Nat., 10(1a), 1-160. Sam Y. (2009) - Etude paléontologique, archéozoologi- que et taphonomique des grands mammifères du site Pléistocène moyen d’Orgnac 3 (Ardèche, France) PhD dissertation, University of Perpignan, France. Schreve D. (2001) - Differentiation of the British late Middle Pleistocene interglacials: the evidence from mammalian biostratigraphy. Quaternary Sci- ence Reviews, 20(16-17), 1693-1705. Stewart J.R. (2008) - The progressive effect of the indi- vidualistic response of species to Quaternary cli- mate change: an analysis of British mammalian faunas. Quaternary Science Reviews, 27(27-28), 2499-2508. Tedford R.H. (1970) - Principles and practices of mam- malian geochronology in North America. In Pro- ceedings of the North American Paleontological Convention, 1 (Part F), 666-703. Wood 2nd H.E., Chaney R.W., Clark J., Colbert E.H., Jepsen G.L., Reeside Jr J.B., Stock C. and Com- mittee (1941) - Nomenclature and correlation of the North American continental Tertiary. Bulletin of the Geological Society of America, 52(1), 1-48. 180 Palombo M.R. Ms. received: May 2, 2018 Final text received: May 14, 2018