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Equus cf. tabeti. (A) Skull in lateral view; (B) Skull in ventral view; (C) Upper tooth row in occlusal view.
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We report here ecological and morphological characterization of the main Old World Equus in North America, Asia, Europe, and Africa, by comparing the studied fossil forms with the living Equus grevyi zebra. Equus simplicidens from North America, Equus livenzovenzis, Equus stenonis, and Equus stehlini from Italy, Equus sivalensis from India, Equus c...
Citations
... ; https://doi.org/10.1101/2024.04.24.590946 doi: bioRxiv preprint non centromeric termini could represent relics of ancestral inactivated centromeres suggesting that this species might be closer to the common ancestor than asses and other zebras. Indeed, Equus grevyi is the only extant member of the subgenus Dolichohippus and, according to paleontological, ecological and morphological evidence, is considered closer to the Eurasian ancestor than the other zebras, which are grouped in the subgenus Hippotigris (63,64). ...
Background
While CENP-A is the epigenetic determinant of the centromeric function, the role of CENP-B, the sole centromeric protein binding a specific DNA sequence (CENP-B-box), remains elusive. In the few mammalian species analyzed so far, the CENP-B box is contained in the major satellite repeat that is present at all centromeres. We previously demonstrated that, in the genus Equus, whose species underwent rapid and recent evolution, numerous centromeres lack any satellite repeat.
Results
In four Equus species, CENP-B is expressed but does not bind the satellite-free and the majority of satellite-based centromeres while it is localized at several ancestral now inactive centromeres. Centromeres lacking CENP-B are functional and recruit normal amounts of CENP-A and CENP-C. The absence of CENP-B is related to the lack of CENP-B boxes rather than to peculiar features of the protein itself. CENP-B boxes are comprised in a previously undescribed repeat which is not the major satellite bound by CENP-A. Comparative sequence analysis suggested that this satellite was centromeric in the equid ancestor, lost centromeric function during evolution and gave rise to a shorter CENP-A bound repeat not containing the CENP-B box but being enriched in dyad symmetries.
Conclusions
We propose that the uncoupling between CENP-B and CENP-A may have played a role in the extensive evolutionary reshuffling of equid centromeres. This study provides new insights into the complexity of centromere organization in a largely biodiverse world where the majority of mammalian species still have to be studied.
... The dispersal of the monodactyl equids into Eurasia at the onset of the Early Pleistocene has usually been considered one of the main events marking turnover of Late Pliocene-Early Pleistocene Eurasian faunas, and the beginning of the Quaternary, 2.58 Ma (Lindsey et al. 1980;Azzaroli, 1983Azzaroli, , 1990Azzaroli, , 1992Azzaroli, , 2000Azzaroli, , 2003Forsten, 1997;Alberdi et al., 1997Alberdi et al., , 2001Alberdi et al., , 1998Eisenmann, , 2006Eisenmann, , 2022aEisenmann, , 2022bRook and Martínez-Navarro, 2010;Kahlke et al., 2011;Bernor et al., 2018Bernor et al., , 2019Bernor et al., , 2021Rook et al., 2019;Cirilli et al., 2021aCirilli et al., , 2021bCirilli et al., , 2021cCirilli et al., , 2022Cirilli et al., , 2023aCirilli et al., , 2023bCirilli, 2022;Bartolini-Lucenti et al., 2022a, 2022b. This biochronological event is known as the Equus Datum (or Equus Event) (Lindsay et al., 1980;Bernor et al., 2019;Rook et al., 2019;Cirilli et al., 2021bCirilli et al., , 2022. ...
... The dispersal of the monodactyl equids into Eurasia at the onset of the Early Pleistocene has usually been considered one of the main events marking turnover of Late Pliocene-Early Pleistocene Eurasian faunas, and the beginning of the Quaternary, 2.58 Ma (Lindsey et al. 1980;Azzaroli, 1983Azzaroli, , 1990Azzaroli, , 1992Azzaroli, , 2000Azzaroli, , 2003Forsten, 1997;Alberdi et al., 1997Alberdi et al., , 2001Alberdi et al., , 1998Eisenmann, , 2006Eisenmann, , 2022aEisenmann, , 2022bRook and Martínez-Navarro, 2010;Kahlke et al., 2011;Bernor et al., 2018Bernor et al., , 2019Bernor et al., , 2021Rook et al., 2019;Cirilli et al., 2021aCirilli et al., , 2021bCirilli et al., , 2021cCirilli et al., , 2022Cirilli et al., , 2023aCirilli et al., , 2023bCirilli, 2022;Bartolini-Lucenti et al., 2022a, 2022b. This biochronological event is known as the Equus Datum (or Equus Event) (Lindsay et al., 1980;Bernor et al., 2019;Rook et al., 2019;Cirilli et al., 2021bCirilli et al., , 2022. ...
... On the other hand, the fossil record of the European Late Pliocene -Early Pleistocene equids is well depicted (see among others Koufos, 1992, Koufos et al., 1997, 2022Alberdi et al., 1997Alberdi et al., , 1998Eisenmann, , 2006Alberdi and Palombo 2013;Bernor et al., 2018Bernor et al., , 2019Bernor et al., , 2021Boulbes and Van Asperen, 2019;Gkeme et al., 2021;Cirilli et al., 2020aCirilli et al., , 2020bCirilli et al., , 2021aCirilli et al., , 2021bCirilli et al., , 2021cCirilli et al., , 2022Cirilli et al., , 2023aCirilli et al., , 2023bCirilli, 2022). Recent research has established Equus livenzovensis as the first occurring member of the genus in Europe at ca. 2.6 Ma (Alberdi et al., 1997(Alberdi et al., , 1998(Alberdi et al., , 2001Bernor et al., 2018Bernor et al., , 2019Bernor et al., , 2021Cirilli et al., 2021aCirilli et al., , 2021bCirilli et al., , 2021cCirilli et al., , 2022. ...
Despite its description at the end of the XIX Century, the alpha-taxonomy, paleobiogeography and biochronology of Equus major remains obscure and ill-defined, leaving a gap of knowledge in the evolutionary history of the Eurasian Palearctic Early Pleistocene Equus species. In this contribution, we describe the Early Pleistocene E. major samples from Pardines and Senèze, providing a comparison by multivariate and statistical analyses with the Early and Middle Pleistocene European stenonid fossil Equus species. Moreover, we explore the paleoecology of E. major by mesowear and body mass estimates, comparing its palaeobiogeographic distribution with European paleoclimatic conditions during the Early Pleistocene. Our outcomes help to clarify the fossil record of E. major, leading to our interpretation that it was the largest Early Pleistocene Equus in Europe, it had a browse-dominated to mixed-feeding diet and was well adapted to humid and forested parts of Europe during the earliest Pleistocene. Eventually, the comparison of our paleoclimatic map with the European fossil record provides new insights in understanding their distribution in time and space during the Early Pleistocene, allowing to clarify details surrounding the Equus Datum in Western Eurasia.
... The taxonomy, phylogenetic relationships and chronological distribution of Equus species recorded in different Middle Pleistocene southern European local faunal assemblages (LFAs) are still a highly debated topic (see, e.g. Palombo and Alberdi 2017;Bernor et al. 2019;Boulbes and van Asperen 2019;Cirilli et al. 2022;Eisenmann 2022). The equids most frequently reported in Europe during the early Middle Pleistocene are Equus altidens and Equus suessenbornensis, which some authors (cfr. ...
... Data on body mass obtained from Alberdi et al. (1995), Nowak (1999, Eisenmann (2000), Ernest (2003), Shoemaker and Clauset (2014), Cantalapiedra et al. (2017), Zedda et al. (2020), Nacarino-Meneses and Orlandi-Oliveras (2021) and Saarinen et al. (2021). Body mass of Equus sivalensis was estimated using the data published in Bernor et al. (2019) and the equations provided by Alberdi et al. (1995) family by several authors (Shoemaker & Clauset, 2014;Cantalapiedra et al., 2017, see also Chap. 2 ...
... Data on body mass obtained from Alberdi et al. (1995), Nowak (1999), Eisenmann (2000), Ernest (2003), Shoemaker and Clauset (2014), Cantalapiedra et al. (2017), Zedda et al. (2020), Nacarino-Meneses and Orlandi-Oliveras (2021) and Saarinen et al. (2021). Body mass of Equus sivalensis was estimated using the data published in Bernor et al. (2019) and the equations provided by Alberdi et al. (1995). Black colour depicts extinct taxa, while grey colour indicates extant species. ...
... The distribution of stenonoid and caballoid horses during the Pleistocene of Asia was not restricted to China. In the Indian subcontinent, the large stenonoid Equus sivalensis (400 kg, own estimation based on data from Bernor et al., 2019;Fig. 5.2d) from the Siwalik hills (India) was a common taxon in the Early Pleistocene (2.6-0.6 Ma) . ...
Body size plays a central role in the biology, physiology, and ecology of organisms. It further represents a main characteristic of the evolutionary history of horses, as these animals experienced multiple changes in body size since their first appearance in the Eocene. The traditional view considering equids as a paradigm of body size increase over time (i.e., Cope’s rule) is now demonstrated to be out of date, as both dwarfing and gigantism processes have been shown in multiple lineages. The only extant genus of horses, the genus Equus, itself experienced significant variations in body size during the Pleistocene. Generally, extinct true horses and zebra-like equids decreased in size during their evolution in Eurasia and Africa while they increased in body size in North America. Equid body size trends have been related to changes in climate, habitat and resources and, more recently, to variations in key life history traits. Extant wild Equus have a mass of between 200 and 400 kg and do not generally show much sexual dimorphism in body mass. Domesticated equids also present a wide range of sizes that, in the case of horse breeds, result from mutations in only a few genes.
... The earliest records of Equus in Eurasia seem to occur in the Lower Pleistocene, at the Gauss-Matuyama paleomagnetic boundary Cirilli et al., 2021aCirilli et al., , b, c, 2022Rook et al., 2019;Sun & Deng, 2019). Given this concurrent appearance, the Plio-Pleistocene boundary at 2.58 Ma, the "Equus Datum" in Eurasia is conventionally referred to this boundary (Azzaroli, 1989;Bernor et al., 2019;Lindsay et al., 1980;Rook et al., 2019;Sun & Deng, 2019). Herein, we report a specimen of Equus from the Siwalik Group in India found just below the Gauss-Matuyama boundary, and therefore making it slightly older than 2.58 Ma. ...
... The Himalayan Foreland Basin which preserves the Mio-Pleistocene Siwalik Group and co-eval deposits (Flynn et al., , 2016, along with younger Quaternary sediments from peninsular India (Chauhan, 2008) have produced an extensive record of both three-toed and one-toed horses (Azzaroli, 1982;Badam, 1979;Bernor et al., 2019;Bernor & Hussain, 1985;Gaur & Chopra, 1984;Hooijer, 1951;Hopwood, 1936;Hussain, 1971;Jukar et al., 2018Jukar et al., , 2019Lydekker, 1882;MacFadden & Woodburne, 1982;Nanda, 2015;Rook et al., 2019;Sahni & Khan, 1961a, 1961bWolf et al., 2013). It is generally believed that Equus first appears in the Upper Siwalik Pinjor Formation (and equivalent sediments), and has been used as a biostratigraphic marker to divide the Upper Siwalik fauna into the Equus-bearing Pleistocene Pinjor Formation, and older Pliocene sediments without Equus (Nanda, 2002;Sahni & Khan, 1964). ...
Fossil horses are ubiquitous members of late Neogene and Quaternary ecosystems in Eurasia and Africa. ThegenusEquusis conventionally thought to be a Pleistocene immigrant into Eurasia from North America, and the concurrentappearance of these monodactyl equids in Eurasia around 2.58 Ma is accepted as theEquusDatum. Here, we report on aspecimen ofEquusfound near the village of Jhil, from the latest Pliocene of the Upper Siwaliks of India. The specimenwas recovered from sediments that are lithologically equivalent to the Upper Pliocene Saketi Formation, and have beendated paleomagnetically to lie just below the Gauss–Matuyama boundary, therefore, the latest Pliocene. Our comparativework shows that the anatomy of Jhil specimen is consistent with the Early Pleistocene Siwalik horse,Equus sivalensis. Ourfinding extends the temporal distribution of this species into the latest Pliocene, and adds to our understanding of thevariation in this species of horse. We also argue that along with potential latest Pliocene occurrences ofEquusfromEurope, and accounting for the Signor–Lipps effect, theEquusDatum should be revised as a latest Pliocene event.
... While Eisenmann (2004) described some specimens of E. stenonis from Saint Vallier, ca. 2.2 Ma which was regarded as its oldest occurrence in Europe (Bernor et al., 2019) and it is probably contemporary to Xinyaozi specimen. ...
Abundant mammalian fossils were uncovered during the field exploration for Nihewan beds at the beginning of the 1980s along Xinyaozi Ravine at Nangaoya Township of Tianzhen County, Shanxi Province in North China. But most equid material was not yet described except that of Equus stenonis. Six forms of Nihewanian equids were confirmed from the Xinyaozi specimens in the present study, five of which were described for the first time. They include four stenonids such as Equus sanmeniensis, E. teilhardi, E. huanghoensis and E. stenonis, and two hipparionines such as Hipparion (Proboscidipparion) sinense and H. (Plesiohiparrion) shanxiense. The diversification of stenonids in the Early Pleistocene was significant in North China with four taxa in Xinyaozi alone. The persistence of Neogene relics such as hipparionines was still present in the Early Pleistocene with two hipparionine taxa in Xinyaozi. Equus sanmeniensis and H. (Proboscidipparion) sinense were two representative equids not only coexisted in the Early Pleistocene but also widely distributed in China. The diversity of equids also implies the diversified vegetation on which they depended. The hypsodont dentitions and well developed cement, as well as completely molarized premolars of Xinyaozi equids indicate their abrasive diet mostly on monocotyledonous and grassland habitats with considerable scales enough to nourish six taxa of equids.
... The Pliocene and Early Pleistocene three-toed horses of Western Eurasia (India, Caucasus, Anatolia, Balkans, Eastern and Central Europe, Italian and Iberian Peninsulas and England) have been studied since the second half of the 19th Century, with multiple genera, species and subspecies assignments (Gervais, 1859;Dep eret, 1890;Stehlin, 1904;Hern andez-Pacheco, 1921;Gromova, 1952;Villalta Comella, 1952;Pirlot, 1956;Kretzoi, 1954;Rǎdulescu and Samson, 1967;Macarovici, 1967;Forsten, 1968Forsten, , 1984Forsten, , 1997Forsten, , 2001Forsten, , 2002Koenigswald, 1970;Crusafont and Sondaar, 1971;Vekua, 1972;Eisenmann and Brunet, 1973;Alberdi, 1974Alberdi, , 1986Koufos, 1982Koufos, , 2017Bernor and Lipscomb, 1991;Alberdi and Aymar, 1995;Bernor et al., 1996Bernor et al., , 2019Bernor et al., , 2021Eisenmann and Sondaar, 1998;Alberdi and Alcal a, 1999;Zouhri and Bensalmia, 2005;Montoya et al., 2006;Bernor and Sen, 2017;Rook et al., 2017;Athanassiou, 2018;Jukar et al., 2019;Cirilli et al., 2021a). These studies accumulated significant information about the geographic and chronologic occurrence of European Plio-Pleistocene hipparionin horses, although issues concerning their taxonomy, evolution, paleobiogeography and biochronology still remain unresolved. ...
... supporting an age of the site close to the Plio-Pleistocene boundary. The Equus Datum has been identified as an important Old World biochronological event, coinciding with the lower boundary of the Pleistocene at 2.58 Ma, defining the base of MNQ16b (Lindsay et al., 1980;Azzaroli, 1983;Alberdi et al., 1998;Bernor et al., 2018Bernor et al., , 2019Cirilli et al., 2021aCirilli et al., , 2021bCirilli et al., , 2021cCirilli et al., , 2022. Equus livenzovensis co-occurs with Pl. rocinantis at Roca-Neyra, however it is represented only by three mandibular cheek teeth (Cirilli et al., 2021a), whereas most of the equid remains are of Pl. rocinantis (Stehlin, 1904). ...
The Pliocene and Early Pleistocene three-toed horses of Western Eurasia (Caucasus, Anatolia, Balkans, Eastern and Central Europe, Italian and Iberian Peninsulas and England) have been studied since the second half of the 19th Century, leading to different interpretations of their taxonomy and evolution. Herein we provide a revision of the taxa from these countries, based principally on the large equid samples from the localities of Villarroya (Iberian Peninsula) and Kvabebi (Georgia). The equid samples from these two localities are compared to a large suite of Old World hipparions from Late Miocene to Early Pleistocene, to identify the diverse genera and species occurring in the Pliocene and Early Pleis-tocene from the Caucasus to the Iberian Peninsula. Moreover, we provide a revised interpretation of their taxonomy, chronology, paleobiogeography and evolutionary history. During the Plio-Pleistocene, we recognize the presence of three genera and six species (Cremohipparion sp., Proboscidipparion heintzi, Proboscidipparion crassum, Plesiohipparion longipes, "Plesiohipparion" fissurae and Plesiohipparion roci-nantis) with a different distribution in time and space for these lineages in the Pliocene and Early Pleistocene.
... The alpha taxonomy of the faunal assemblage was comprehensively described in a monograph by Vekua (1995). Since then, further descriptions and revisions of the mammalian taxonomic assignments have been made by several paleontologists (Bukhsianidze, 2005(Bukhsianidze, , 2016Bukhsianidze and Vekua, 2006;Furio et al., 2010;Hemmer et al., 2010Hemmer et al., , 2011Vekua et al., 2010a;Blain et al., 2014;Bernor et al., 2019Bernor et al., , 2021Cappellini et al., 2019;Medin et al., 2019;Bartolini-Lucenti et al., 2020. We follow their work for specific identifications. ...
There are many hypotheses regarding influences on the early hominin biogeographic spread into Eurasia; among them is increased meat-eating. Dmanisi in Georgia is one of the rare Early Pleistocene sites in Eurasia, and here we present primary information and analysis of the medium and large mammal taphonomy, contributing information about site formation and the hominins' interaction with the fauna. Nearly 85% of the specimens come from the B1 stratum. Relative abundances of mammal families demonstrate some bias toward carnivores, especially Canis borjgali, and diverse Felidae species. Bones display little weathering. Post-depositional surface modifications and matrix obscure many bone surfaces, but carnivore tooth marking is the most common bone surface modification from the nutritive taphonomic phase. Tooth pits are large, in the size range of those made by modern Crocuta crocuta and Panthera leo. Breakage variables indicate most breaks occurred while the bones were still fresh, many by carnivore consumption. Fairly even limb bone representation of herbivores suggests carcasses were introduced to the site nearly whole. Hominin tool marks are present in low frequencies, but they suggest a variety of behaviors. These marks are found on Equus, Palaeotragus, Bison, large cervids, Pseudodama, Canis, and Mammuthus. Some were made by filleting proximal limb segments, and so are likely indicative of early access to carcasses, while other marks suggest scavenging. The Homo taphonomic variables resemble the rest of the taphonomic signatures from the site with little weathering, a slightly higher percentage of their bones are whole, but only a few have probable carnivore damage. The assemblage characteristics are compared to modern actualistic and experimental assemblages, and it is concluded that Dmanisi presents a palimpsest of hyena denning, felid activity, hominin meat-eating and likely natural deaths.
... A very large cranium, lacking its posterior part but otherwise very well preserved, was found in member 1 of the Olorgesailie Formation, Kenya inside the Acheulean levels circa 1 Ma old [77]. This specimen (Figure 50), KNM-OG (Kenya National Museums, OG: Olorgesailie, Nairobi, Kenya) 22833, was referred to E. oldowayensis [12]. The holotype of this species was lost during the war; the paratype-a lower incisive region-is inadequate, as pointed out by Bernor et al. [12]. ...
... This specimen (Figure 50), KNM-OG (Kenya National Museums, OG: Olorgesailie, Nairobi, Kenya) 22833, was referred to E. oldowayensis [12]. The holotype of this species was lost during the war; the paratype-a lower incisive region-is inadequate, as pointed out by Bernor et al. [12]. The neotype chosen by Churcher and Hooijer [78] is a mandible whose precise provenance is unfortunately not known. ...
... The age of the Algerian E. (Quagga) mauritanicus is about 700 ka [76] or 800 ka [69]. The cranium referred to E. oldowayensis [12] was found in member 1 of the Olorgesailie Formation, Kenya inside Acheulean levels circa 1 Ma old [77]. ...
Discussion of the phylogenetic relations between Plesippus, Allohippus, and Equus. Descriptions and illustrations of 30 Equid extant and fossil species younger than 2 Ma. Particular attention is given to slender forms with short protocones usually referred to ‘Equus altidens’ from Süssenborn and Untermassfeld (Germany), Akhalkalaki and Dmanisi (Georgia), Pirro (Italy), Venta Micena (Spain) and Aïn Hanech (Algeria). Occurrence of Asinine features in fossil taxa from Africa, Greece, Mongolia, and North-Eastern Siberia. Supplementary materials include additional discussions and photographs of fossils in particular from Süssenborn (especially those referred to E. altidens and E. marxi by Reichenau) and from Dmanisi from where a new species is described.
... It is a large species of stenonine horse found in the Siwaliks of the Indian Subcontinent, ranging from the Potwar Plateau in the west to the Nepal Siwaliks in the east. The exact temporal distribution is unknown; however, based on paleomagnetic dating of the Pinjor Formation where the species was found, it likely ranges in age from 2.6 to 0.6 Ma [176,184]. However, some potentially older occurrences from just below the Gauss-Matuyama boundary (>2.6 Ma) have also been reported [185,186]. ...
... E. sivalensis [189]. A set of postcranial remains, including metapodials, astragali and phalanges, which were formerly tentatively referred to as "Hippotherium" antelopinum, are now believed to belong to this small species of Equus [138,184]. Based on specimens collected from the Mangla-Samwal Anticline and the Pabbi Hills in Pakistan, this species likely ranges in age from ~2.2 to 1.2 Ma [176]. Geographically, it ranges from the Pabbi Hills to the river Yamuna in the east. ...
... The Pliocene and Pleistocene are characterized by the persistence of Cremohipparion, and the dispersion of Proboscidipparion and Plesiohipparion [7], represented by five species. The Equus Datum is represented by the oldest species, Equus livenzovensis, at ca. 2.6 Ma in Russia, Italy, France and Spain [176], which led to the Equus stenonis' evolution and to the radiation of the African fossil species [10,13,184,192]. At the present time, we recognize 13 species in the genus Equus during the Pleistocene. ...
Studies of horse evolution arose during the middle of the 19th century, and several hypotheses have been proposed for their taxonomy, paleobiogeography, paleoecology and evolution. The present contribution represents a collaboration of 19 multinational experts with the goal of providing an updated summary of Pliocene and Pleistocene North, Central and South American, Eurasian and African horses. At the present time, we recognize 114 valid species across these continents, plus 4 North African species in need of further investigation. Our biochronology and biogeography sections integrate Equinae taxonomic records with their chronologic and geographic ranges recognizing regional biochronologic frameworks. The paleoecology section provides insights into paleobotany and diet utilizing both the mesowear and light microscopic methods, along with calculation of body masses. We provide a temporal sequence of maps that render paleoclimatic conditions across these continents integrated with Equinae occurrences. These records reveal a succession of extinctions of primitive lineages and the rise and diversification of more modern taxa. Two recent morphological-based cladistic analyses are presented here as competing hypotheses, with reference to molecular-based phylogenies. Our contribution represents a state-of-the art understanding of Plio-Pleistocene Equus evolution, their biochronologic and biogeographic background and paleoecological and paleoclimatic contexts.
