Kvabebi fossil site
ქვაბების ფაუნა (Georgian) | |
  Shown within Georgia  Kvabebi fossil site (Asia)  Kvabebi fossil site (Europe) | |
| Location | Mount Kvabebi, Iori Plateau |
|---|---|
| Region | Sighnaghi Municipality, Georgia |
| Coordinates | 41°27′28.5″N 45°42′43.4″E / 41.457917°N 45.712056°E |
| Type | Paleontological |
| History | |
| Periods | Miocene |
The Kvabebi fossil site (Georgian: ქვაბების ფაუნა) is a Pliocene paleontological locality in eastern Georgia's Iori Plateau, known for its rich vertebrate assemblage that is key to understanding of Eurasian biogeography and early human dispersal. Dated to around 3.07 million years ago (Ma), it preserves a mix of Eurasian taxa and Miocene relicts from the Greek-Iranian province — a Late Miocene Eurasian biome hosting extinct savanna species. Research since 2009 has refuted earlier hypotheses that Kvabebi represented an "African bridge" for early hominin dispersal, instead revealing it as a dead-end refuge for ancient lineages.
Location and discovery
[edit]Located at Mount Kvabebi on the southern edge of Georgia's Iori Plateau near the Magharo village, Signaghi Municipality, the Kvabebi fossil site was discovered in 1962 when geologist G. Avakov unearthed a lone vertebra. Between the 1960s and 1970s, the Georgian Academy of Sciences expeditions recovered over 800 vertebrate specimens from the Kura Basin's layered sediments — a trove later cataloged in A. Vekua's 1972 monograph. Renewed fieldwork in the 2000s by Georgian-Spanish teams reinterpreted the site with implications for understanding continental biogeography.[1]
Geological setting
[edit]At the base of Kvabebi's 170-meter-thick exposure lie marine mudstones studded with Caspian Sea mollusks like Avimactra and Cardium — relics of a time when the Paratethys Ocean flooded the region. Higher strata transition to continental sandstones, where two volcanic ash layers bracket the fossil bed at 40 meters depth. Here, disarticulated bones weathered by ancient rivers lie preserved, untouched by scavengers.[1]
Paleomagnetic analysis pinned these fossils to reverse Chron C2An.1r, dating them to around 3.07 million years ago. This places Kvabebi contemporaneous with Ethiopia's Hadar Formation and older than Europe's last Hipparion horse sites. Critical biochronological markers like the three-toed horse Hipparion rocinantis and early deer Eucladoceros confirm Kvabebi's role as a pre-Equus ecosystem.[1]
Fossil assemblage
[edit]The site yielded 138 individuals across more than 23 species. Dominant Eurasian taxa included elephant-like Anancus arvernensis, sabertooth cats (Homotherium) and hyenas (Chasmaportetes) as well as fleet-footed deer (Procapreolus and Pseudalces), alongside canids like the raccoon dog Nyctereutes megamastoides and the ancestral red fox Vulpes alopecoides. The so-called "African" species were giant hyraxes (Kvabebihyrax kachetikus), spiral-horned antelopes (Parastrepsiceros), and gazelles (Gazella postmitilini). Initially, these were interpreted by Vekua (1972) and Dennell & Roebroeks (2005)[2] as evidence of Pliocene migrations from Africa — a "faunal bridge" for later hominins.[1]
The renewed studies by Agustí and Vekua in the 2000s revealed that the site's "African-affinity" species — including the giant hyrax Kvabebihyrax — were not evidence of Pliocene migrations from Africa as previously thought. Instead, these taxa were relicts of Eurasia's extinct Greek-Iranian province — a vast Late Miocene (11–5 Ma) savanna-woodland biome stretching from Greece to Iran. Also, Rook et al identified Vulpes alopecoides as the earliest known occurrence of this fox in Europe, demonstrating niche partitioning with coexisting canids like Nyctereutes and Eucyon.[3] When aridification fragmented this ecosystem around 8–7 million years ago, species like hyraxes, antelopes, and specialized canids retreated to refuges.[1]
| Taxon | Common name / Description | NISP | MNI | Biogeographic affinity | Notes |
|---|---|---|---|---|---|
| Kvabebihyrax kachethicus | Giant hyrax (sheep-sized) | 11 | 5 | Greek-Iranian relict | Descendant of European Pilohyrax; last Eurasian hyrax |
| Hipparion rocinantis | Three-toed horse | 83 | 8 | Eurasian | Last hipparionine horse in W. Eurasia; pre-Equus |
| Ioribos aceros | Bovid (local Leptobos relative) | 234 | 28 | Eurasian | Dominant herbivore; endemic to Caucasus |
| Protoryx heinrichi | Spiral-horned antelope | 72 | 17 | Greek-Iranian relict | Pikermian biome survivor |
| Parasirepsiceros sokolovi | Spiral-horned antelope | 84 | 14 | Greek-Iranian relict | Greek-Iranian province endemic |
| Gazella postmitilini | Gazelle | 80 | 9 | Greek-Iranian relict | Convergent with African gazelles |
| Anancus arvernensis | Gomphothere elephant | 35 | 4 | Eurasian | Last European shovel-tusker |
| Homotherium davitashvili | Scimitar-toothed cat | 7 | 1 | Eurasian | Early Homotherium species |
| Stephanorhinus megarhinus | Woolly rhinoceros ancestor | 53 | 16 | Eurasian | Cold-adapted precursor |
| Puma pardoides | Eurasian puma | 2 | 1 | Greek-Iranian relict | Earliest puma in Eurasia |
| Chasmaportetes lunensis | Hunting hyena | 1 | 1 | Eurasian | Holarctic distribution |
| Propotamochoerus provincialis | Early suid (pig) | 37 | 8 | Eurasian | Wetland-adapted omnivore |
| Eucladoceros sp. | Bushy-antlered deer | 6 | 3 | Eurasian | Earliest cervid dispersal into Europe |
| Pseudalces sp. | Early elk/moose ancestor | 6 | 2 | Eurasian | Pre-Alces cervid |
| Nycterentes megamastoides | Raccoon dog | 70 | 9 | Eurasian | Opportunistic omnivore |
| Dinofelis abeli | Scimitar cat | 1 | 1 | Greek-Iranian relict | Last Eurasian representative |
| Oryx (Aegoryx) sp. | Beisa oryx-like antelope | 1 | 1 | Greek-Iranian relict | Desert-adapted survivor |
| TOTAL | 808 | 138 | |||
Key:
- NISP: Number of Identified Specimens
- MNI: Minimum Number of Individuals
Implications for human evolution
[edit]Kvabebi's ecosystem — dated to 3.07 Ma — exhibited under 25% faunal similarity to contemporary African sites like Hadar, confirming no functional biological corridor existed with Africa at that time. Furthermore, Kvabebi's relict species (e.g., Kvabebihyrax, Protoryx) are entirely absent at Dmanisi, indicating this fauna vanished by around 2.8 Ma — 1.2 million years before hominins arrived in Georgia's Dmanisi region (around 1.8 Ma).[1]
Thus, Kvabebi represents a dead-end refuge for Miocene survivors, not a "savanna bridge" for hominins. Early humans seem to have expanded not by tracking familiar habitats, but in response to Quaternary ice-age pulses that disrupted African environments.[1]
References
[edit]- ^ a b c d e f g h Agustí, J.; Vekua, A.; Oms, O.; Lordkipanidze, D.; Bukhsianidze, M.; Kiladze, G.; Rook, L. (2009). "The Pliocene-Pleistocene succession of Kvabebi (Georgia) and the background to the early human occupation of Southern Caucasus". Quaternary Science Reviews. 28 (27–28): 3275–3280. doi:10.1016/j.quascirev.2009.09.001.
- ^ Dennell, Robin; Roebroeks, Wil (2005). "An Asian perspective on early human dispersal from Africa". Nature. 438 (7071): 1099–1104. doi:10.1038/nature04259.
- ^ Rook, Lorenzo; Bartolini Lucenti, Saverio; Bukhsianidze, Maia; Lordkipanidze, David (2017). "The Kvabebi Canidae record revisited (late Pliocene, Sighnaghi, eastern Georgia)". Journal of Paleontology. 91 (6): 1258–1271. doi:10.1017/jpa.2017.73.