What Does the “Elephant-<i>Equus</i>” Event Mean Today? Reflections on Mammal Dispersal Events around the Pliocene-Pleistocene Boundary and the Flexible Ambiguity of Biochronology
The dispersal of primitive elephantines and monodactyl equids in Eurasia has long been regarded as representative of a substantial turnover in mammal faunas, denoting the spread of open environments linked to the onset of cold and dry conditions in the Northern Hemisphere. During the 1980s, this eve...
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| Format: | Article |
| Language: | English |
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MDPI AG
2023-02-01
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| Series: | Quaternary |
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| Online Access: | https://www.mdpi.com/2571-550X/6/1/16 |
| _version_ | 1797609281561821184 |
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| author | Alessio Iannucci Raffaele Sardella |
| author_facet | Alessio Iannucci Raffaele Sardella |
| author_sort | Alessio Iannucci |
| collection | DOAJ |
| description | The dispersal of primitive elephantines and monodactyl equids in Eurasia has long been regarded as representative of a substantial turnover in mammal faunas, denoting the spread of open environments linked to the onset of cold and dry conditions in the Northern Hemisphere. During the 1980s, this event was named the “Elephant-<i>Equus</i> event” and it was correlated with the Gauss-Matuyama reversal, today corresponding to the Pliocene-Pleistocene transition and the beginning of the Quaternary, dated at ~2.6 Ma. Therefore, the Elephant-<i>Equus</i> event became a concept of prominent biochronological and paleoecological significance, especially in western Europe. Yet, uncertainties surrounding the taxonomy and chronology of early “elephant” and “<i>Equus</i>”, as well as conceptual differences in adopting (or understanding) the Elephant-<i>Equus</i> event as an intercontinental dispersal event or as a stratigraphic datum, engendered ambiguity and debate. Here, we provide a succinct review of the Elephant-<i>Equus</i> event, considering separately the available evidence on the “elephant” and the “<i>Equus</i>”. Elephantines dispersed out of Africa during the Pliocene (Piacenzian). Their earliest calibrated occurrences from eastern Europe date at ~3.2 Ma and they are usually referred to <i>Mammuthus rumanus</i>, although the allocation of several samples to this species is tentative. Available dating constraints for other localities do not resolve whether the dispersal of <i>Mammuthus</i> was synchronous across Eurasia, but this possibility cannot be ruled out. The spread of <i>Mammuthus</i> was part of an intercontinental faunal exchange between Africa and Eurasia that occurred during the Piacenzian, but in this scenario, <i>Mammuthus</i> is quite unique in being the only genus of African origin dispersing to western Eurasia. The arrival of monodactyl equids from North America coincides with the Pliocene-Pleistocene transition, with several occurrences dated or calibrated at ~2.6 Ma and no compelling evidence prior to this age. In Europe, early monodactyl equids are often aligned to <i>Equus livenzovensis</i>, but the material from the type locality of this species is chronologically time-averaged and taxonomically heterogeneous, and western European samples are seldom abundant or informative. Regardless, this does not diminish the biochronological significance of the “<i>Equus</i> event”. Indeed, while the term “Elephant-<i>Equus</i> event” should no longer be used, as the appearance of elephantines in the European fossil record markedly precedes that of monodactyl equids, we endorse the use of the “<i>Equus</i> event” as a valid alternative to refer to the intercontinental dispersal event that characterizes the middle Villafranchian faunal turnover, epitomized by but not limited to monodactyl equids. |
| first_indexed | 2024-03-11T05:58:21Z |
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| id | doaj.art-7dccb412d8d74791bce367038581353f |
| institution | Directory Open Access Journal |
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| language | English |
| last_indexed | 2024-03-11T05:58:21Z |
| publishDate | 2023-02-01 |
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| series | Quaternary |
| spelling | doaj.art-7dccb412d8d74791bce367038581353f2023-11-17T13:35:02ZengMDPI AGQuaternary2571-550X2023-02-01611610.3390/quat6010016What Does the “Elephant-<i>Equus</i>” Event Mean Today? Reflections on Mammal Dispersal Events around the Pliocene-Pleistocene Boundary and the Flexible Ambiguity of BiochronologyAlessio Iannucci0Raffaele Sardella1Dipartimento di Scienze della Terra (PaleoFactory Lab.), Sapienza Università di Roma, P.le Aldo Moro 5, I-00185 Roma, ItalyDipartimento di Scienze della Terra (PaleoFactory Lab.), Sapienza Università di Roma, P.le Aldo Moro 5, I-00185 Roma, ItalyThe dispersal of primitive elephantines and monodactyl equids in Eurasia has long been regarded as representative of a substantial turnover in mammal faunas, denoting the spread of open environments linked to the onset of cold and dry conditions in the Northern Hemisphere. During the 1980s, this event was named the “Elephant-<i>Equus</i> event” and it was correlated with the Gauss-Matuyama reversal, today corresponding to the Pliocene-Pleistocene transition and the beginning of the Quaternary, dated at ~2.6 Ma. Therefore, the Elephant-<i>Equus</i> event became a concept of prominent biochronological and paleoecological significance, especially in western Europe. Yet, uncertainties surrounding the taxonomy and chronology of early “elephant” and “<i>Equus</i>”, as well as conceptual differences in adopting (or understanding) the Elephant-<i>Equus</i> event as an intercontinental dispersal event or as a stratigraphic datum, engendered ambiguity and debate. Here, we provide a succinct review of the Elephant-<i>Equus</i> event, considering separately the available evidence on the “elephant” and the “<i>Equus</i>”. Elephantines dispersed out of Africa during the Pliocene (Piacenzian). Their earliest calibrated occurrences from eastern Europe date at ~3.2 Ma and they are usually referred to <i>Mammuthus rumanus</i>, although the allocation of several samples to this species is tentative. Available dating constraints for other localities do not resolve whether the dispersal of <i>Mammuthus</i> was synchronous across Eurasia, but this possibility cannot be ruled out. The spread of <i>Mammuthus</i> was part of an intercontinental faunal exchange between Africa and Eurasia that occurred during the Piacenzian, but in this scenario, <i>Mammuthus</i> is quite unique in being the only genus of African origin dispersing to western Eurasia. The arrival of monodactyl equids from North America coincides with the Pliocene-Pleistocene transition, with several occurrences dated or calibrated at ~2.6 Ma and no compelling evidence prior to this age. In Europe, early monodactyl equids are often aligned to <i>Equus livenzovensis</i>, but the material from the type locality of this species is chronologically time-averaged and taxonomically heterogeneous, and western European samples are seldom abundant or informative. Regardless, this does not diminish the biochronological significance of the “<i>Equus</i> event”. Indeed, while the term “Elephant-<i>Equus</i> event” should no longer be used, as the appearance of elephantines in the European fossil record markedly precedes that of monodactyl equids, we endorse the use of the “<i>Equus</i> event” as a valid alternative to refer to the intercontinental dispersal event that characterizes the middle Villafranchian faunal turnover, epitomized by but not limited to monodactyl equids.https://www.mdpi.com/2571-550X/6/1/16biochronologybioeventdispersal event<i>Equus</i> DatumGauss-Matuyama reversalfaunal turnover |
| spellingShingle | Alessio Iannucci Raffaele Sardella What Does the “Elephant-<i>Equus</i>” Event Mean Today? Reflections on Mammal Dispersal Events around the Pliocene-Pleistocene Boundary and the Flexible Ambiguity of Biochronology Quaternary biochronology bioevent dispersal event <i>Equus</i> Datum Gauss-Matuyama reversal faunal turnover |
| title | What Does the “Elephant-<i>Equus</i>” Event Mean Today? Reflections on Mammal Dispersal Events around the Pliocene-Pleistocene Boundary and the Flexible Ambiguity of Biochronology |
| title_full | What Does the “Elephant-<i>Equus</i>” Event Mean Today? Reflections on Mammal Dispersal Events around the Pliocene-Pleistocene Boundary and the Flexible Ambiguity of Biochronology |
| title_fullStr | What Does the “Elephant-<i>Equus</i>” Event Mean Today? Reflections on Mammal Dispersal Events around the Pliocene-Pleistocene Boundary and the Flexible Ambiguity of Biochronology |
| title_full_unstemmed | What Does the “Elephant-<i>Equus</i>” Event Mean Today? Reflections on Mammal Dispersal Events around the Pliocene-Pleistocene Boundary and the Flexible Ambiguity of Biochronology |
| title_short | What Does the “Elephant-<i>Equus</i>” Event Mean Today? Reflections on Mammal Dispersal Events around the Pliocene-Pleistocene Boundary and the Flexible Ambiguity of Biochronology |
| title_sort | what does the elephant i equus i event mean today reflections on mammal dispersal events around the pliocene pleistocene boundary and the flexible ambiguity of biochronology |
| topic | biochronology bioevent dispersal event <i>Equus</i> Datum Gauss-Matuyama reversal faunal turnover |
| url | https://www.mdpi.com/2571-550X/6/1/16 |
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