Tadzhikosuchus is an extinct genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of crocodylomorph

Crocodylomorpha

The Crocodylomorpha are an important group of archosaurs that include the crocodilians and their extinct relatives.During Mesozoic and early Tertiary times the Crocodylomorpha were far more diverse than they are now. Triassic forms were small, lightly built, active terrestrial animals. These were...

 that may have been a crocodylid eusuchia

Eusuchia

Eusuchia is a clade of crocodylomorphs that first appears in the Early Cretaceous with Hylaeochampsa. All living crocodilian species are eusuchians, as are many extinct forms.-Description:...

n. To date it is mostly known from partial dentaries that show it to have been very similar to Diplocynodon

Diplocynodon

Diplocynodon is an extinct genus of alligatoroid that lived during the Paleocene to middle Miocene 49 million years ago in Europe. It looked very similar to the modern caiman in that it was small and had bony armour scutes covering its neck, back, belly, and tail...

, if not the same genus. The two are differentiated by subtle differences in tooth position and tooth socket shape, and by differences in stratigraphy

Stratigraphy

Stratigraphy, a branch of geology, studies rock layers and layering . It is primarily used in the study of sedimentary and layered volcanic rocks....

 (Diplocynodon was a Tertiary

Tertiary

The Tertiary is a deprecated term for a geologic period 65 million to 2.6 million years ago. The Tertiary covered the time span between the superseded Secondary period and the Quaternary...

 genus). Three species have been named: the type species

Type species

In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...

 T. macrodentis from the lower Santonian

Santonian

The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous epoch or Upper Cretaceous series. It spans the time between 85.8 ± 0.7 mya and 83.5 ± 0.7 mya...

-age Upper Cretaceous Yalovach Svita of Kansai, in the Fergana Basin

Fergana Valley

The Fergana Valley or Farghana Valley is a region in Central Asia spreading across eastern Uzbekistan, Kyrgyzstan and Tajikistan. Divided across three subdivisions of the former Soviet Union, the valley is ethnically diverse, and in the early 21st century was the scene of ethnic conflict...

 of Tajikistan

Tajikistan

Tajikistan , officially the Republic of Tajikistan , is a mountainous landlocked country in Central Asia. Afghanistan borders it to the south, Uzbekistan to the west, Kyrgyzstan to the north, and China to the east....

, as described by Efimov in 1982; T. neutralis from the same location, by Efimov in 1988; and T. kizylkumensis from Turonian

Turonian

The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous epoch, or a stage in the Upper Cretaceous series. It spans the time between 93.5 ± 0.8 Ma and 89.3 ± 1 Ma...

-age rocks of the Upper Cretaceous Bissekty Formation

Bissekty Formation

The Bissekty Formation is situated in the Kyzyl Kum desert of Uzbekistan, and dates from the late Cretaceous Period. Laid down in the early the Turonian to Coniacian stages, it is dated to about 90-85 ma .The Bissekty Formation is characterised by a mix of marine, brackish, freshwater, and...

 of Dzharakhuduk, Uzbekistan

Uzbekistan

Uzbekistan , officially the Republic of Uzbekistan is a doubly landlocked country in Central Asia and one of the six independent Turkic states. It shares borders with Kazakhstan to the west and to the north, Kyrgyzstan and Tajikistan to the east, and Afghanistan and Turkmenistan to the south....

, by Nesov and colleagues in 1989. However, a 2000 review by Glenn Storrs and Mikhail Efimov could not differentiate between the species based on their type material

Holotype

A holotype is a single physical example of an organism, known to have been used when the species was formally described. It is either the single such physical example or one of several such, but explicitly designated as the holotype...

, and recommended using T. macrodentis for the specimens of all three species. They also could not determine how Tadzhikosuchus and the contemporaneous Zhyrasuchus

Zhyrasuchus

Zhyrasuchus is an extinct genus of crocodylomorph that may have been a crocodylid eusuchian, but is only known from scanty material including a frontal . Its fossils were found in the Coniacian-age Upper Cretaceous Bissekty Formation of Dzharakhuduk, Uzbekistan. Zhyrasuchus was described in 1989...

were related, or even if they were synonyms, due to the poor fossils available. The name of the Tadzhikosuchus is derived from the Russian spelling of the name of the former Soviet

Soviet Union

The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

republic of Tajikistan.