The Pabdeh Formation is a

Late Eocene The Priabonian is, in the International Commission on Stratigraphy, ICS's geologic timescale, the latest age (geology), age or the upper stage (stratigraphy), stage of the Eocene epoch (geology), Epoch or series (stratigraphy), Series. It spans ...

Early Oligocene The Rupelian is, in the geologic timescale, the older of two age (geology), ages or the lower of two stage (stratigraphy), stages of the Oligocene epoch (geology), Epoch/series (stratigraphy), Series. It spans the time between . It is preceded b ...

-aged geological formation in

Iran Iran, officially the Islamic Republic of Iran (IRI) and also known as Persia, is a country in West Asia. It borders Iraq to the west, Turkey, Azerbaijan, and Armenia to the northwest, the Caspian Sea to the north, Turkmenistan to the nort ...

. It outcrops along the

Zagros Mountains The Zagros Mountains are a mountain range in Iran, northern Iraq, and southeastern Turkey. The mountain range has a total length of . The Zagros range begins in northwestern Iran and roughly follows Iran's western border while covering much of s ...

. It was deposited in a deepwater environment in the upper

bathyal zone The bathypelagic zone or bathyal zone (from Greek βαθύς (bathýs), deep) is the part of the open ocean that extends from a depth of below the ocean surface. It lies between the mesopelagic above and the abyssopelagic below. The bathypela ...

of the Paratethys Sea, with these abyssal sediments being lifted high above sea level from the uplift of the

Zagros fold and thrust belt The Zagros fold and thrust belt (Zagros FTB) is an approximately long zone of deformed crustal rocks, formed in the foreland of the collision between the Arabian plate and the Eurasian plate. It is host to one of the world's largest petroleum ...

as part of the Alpide orogeny. A high number of fossil fishes are known from this formation, the majority of which appear to have pelagic and deepwater affinities. These are mostly known from two localities near

Elam Elam () was an ancient civilization centered in the far west and southwest of Iran, stretching from the lowlands of what is now Khuzestan and Ilam Province as well as a small part of modern-day southern Iraq. The modern name ''Elam'' stems fr ...

and Istehbanat. The age of these localities have been disputed, and have previously been considered to be Early Oligocene, but are now generally thought to be middle to late Eocene in age, most likely

Priabonian The Priabonian is, in the ICS's geologic timescale, the latest age or the upper stage of the Eocene Epoch or Series. It spans the time between . The Priabonian is preceded by the Bartonian and is followed by the Rupelian, the lowest stage ...

. Some fossils of migratory insects (a locust and ant alates), as well as fish and birds, are also known from presumed early Oligocene-aged strata near Babaheidar.

Paleobiota

Cartilaginous fishes

Bony fishes

Based primarily on Arambourg (1967), with taxonomic changes made where necessary:

Birds

Arthropods

Crustaceans

Based on Garassino, Bahrami, Yazdi & Vega (2014):

Insecta

{, class="wikitable" align="center" width="100%" !Genus !Species !Locality !Notes !Images , - ,

Acrididae Acrididae are the predominant family of grasshoppers, comprising some 10,000 of the 11,000 species of the entire suborder Caelifera. The Acrididae are best known because all locusts (swarming grasshoppers) are of the Acrididae. The subfamily Oedi ...

indet. , , rowspan="2" , Babaheidar , A

short-horned grasshopper Grasshoppers are a group of insects belonging to the suborder Caelifera. They are amongst what are possibly the most ancient living groups of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago. Grassh ...

of uncertain affinities, potentially in a migratory

locust Locusts (derived from the Latin ''locusta'', locust or lobster) are various species of short-horned grasshoppers in the family Acrididae that have a swarming phase. These insects are usually solitary, but under certain circumstances they b ...

-like phase.{{Cite journal , last1=Mirzaie Ataabadi , first1=Majid , last2=Bahrami , first2=Ali , last3=Yazdi , first3=Mehdi , last4=Nel , first4=André , date=2019-05-28 , title=A locust witness of a trans-oceanic Oligocene migration between Arabia and Iran (Orthoptera: Acrididae) , url=https://www.tandfonline.com/doi/full/10.1080/08912963.2017.1378651 , journal=Historical Biology , language=en , volume=31 , issue=5 , pages=574–580 , doi=10.1080/08912963.2017.1378651 , issn=0891-2963 , , - , Formicidae indet. , , A potentially

myrmicine Myrmicinae is a subfamily of ants, with about 140 extant genera; their distribution is cosmopolitan. The pupae lack cocoons. Some species retain a functional sting. The petioles of Myrmicinae consist of two nodes. The nests are permanent and ...

ant Ants are Eusociality, eusocial insects of the Family (biology), family Formicidae and, along with the related wasps and bees, belong to the Taxonomy (biology), order Hymenoptera. Ants evolved from Vespoidea, vespoid wasp ancestors in the Cre ...

of uncertain affinities, migratory alates. ,

References

Geologic formations of Iran Zagros Mountains Priabonian Stage Rupelian Stage Open marine deposits Deep marine deposits Paleontology in Iran