The ''

Gomphotherium ''Gomphotherium'' (; "nail beast" for its double set of straight tusks) is an extinct genus of gomphothere proboscidean from the Neogene of Eurasia, Africa and North America. It is the most diverse genus of gompothere, with over a dozen valid sp ...

land bridge'' was a

land bridge In biogeography, a land bridge is an isthmus or wider land connection between otherwise separate areas, over which animals and plants are able to cross and colonize new lands. A land bridge can be created by marine regression, in which sea le ...

that connected

Eurasia Eurasia ( , ) is a continental area on Earth, comprising all of Europe and Asia. According to some geographers, Physical geography, physiographically, Eurasia is a single supercontinent. The concept of Europe and Asia as distinct continents d ...

to Afro-Arabia between approximately 19 Mya (million years ago) and 15 Mya.

Significance

Passage of fauna between

and the Arabian Plate and thus Africa was largely hindered before the

Early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...

, as animals could not cross the open Tethyan seaway. However, during the mid-

Burdigalian The Burdigalian is, in the geologic timescale, an age (geology), age or stage (stratigraphy), stage in the early Miocene. It spans the time between 20.43 ± 0.05 annum, Ma and 15.97 ± 0.05 Ma (million years ago). Preceded by the Aquitanian (sta ...

, the

tectonic plate Plate tectonics (, ) is the scientific theory that the Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of , an idea developed durin ...

s of Afro-Arabia and Eurasia collided, creating a terrestrial

isthmus An isthmus (; : isthmuses or isthmi) is a narrow piece of land connecting two larger areas across an expanse of water by which they are otherwise separated. A tombolo is an isthmus that consists of a spit or bar, and a strait is the sea count ...

connecting the two landmasses. This faunal exchange that resulted is known as the Proboscidean Datum Event. The land bridge allowed the elephantine

gomphothere Gomphotheres are an extinct group of proboscideans related to modern elephants. First appearing in Africa during the Oligocene, they dispersed into Eurasia and North America during the Miocene and arrived in South America during the Pleistocene a ...

s and other

proboscideans Proboscidea (; , ) is a taxonomic order of afrotherian mammals containing one living family (Elephantidae) and several extinct families. First described by J. Illiger in 1811, it encompasses the elephants and their close relatives. Three liv ...

to migrate out of Africa and into Eurasia. It is believed that the connection between the Mediterranean and Indian oceans was temporarily re-established during the

Langhian The Langhian is, in the ICS geologic timescale, an age or stage in the middle Miocene Epoch/Series. It spans the time between 15.97 ± 0.05 Ma and 13.65 ± 0.05 Ma (million years ago) during the Middle Miocene.GeoWhen (2007) The Langhian was ...

stage of the Middle Miocene, before reclosing, and has remained closed to present day.

References

Historical geography Miocene {{Asia-hist-stub