''Janusiscus schultzei'' is an extinct gnathostome vertebrate dating from the

Early Devonian The Early Devonian is the first of three epochs comprising the Devonian period, corresponding to the Lower Devonian series. It lasted from and began with the Lochkovian Stage , which was followed by the Pragian from and then by the Emsian, whi ...

period in

Siberia Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part o ...

, approximately 415 million years ago. It may be the sister group of the last common ancestor of

Chondrichthyes Chondrichthyes (; ) is a class that contains the cartilaginous fishes that have skeletons primarily composed of cartilage. They can be contrasted with the Osteichthyes or ''bony fishes'', which have skeletons primarily composed of bone tissu ...

(cartilaginous fish) or

Osteichthyes Osteichthyes (), popularly referred to as the bony fish, is a diverse superclass of fish that have skeletons primarily composed of bone tissue. They can be contrasted with the Chondrichthyes, which have skeletons primarily composed of cartila ...

(bony fish). This makes ''J. schultzei'' a sister species to all living jawed vertebrates. The species name is in honor of

Hans-Peter Schultze Hans-Peter Schultze (born 13 August 1937 in Swinemünde, Poland) is a German-American paleoichthyologist.Lebensdaten nach ''American Men and Women of Science'', Thomson Gale 2004 He has described the following taxon: *'' Luckeus abudda'' Young ...

; the genus named after

Janus In ancient Roman religion and myth, Janus ( ; la, Ianvs ) is the god of beginnings, gates, transitions, time, duality, doorways, passages, frames, and endings. He is usually depicted as having two faces. The month of January is named for Janu ...

, the Roman god of duality.

Taxonomy

The following cladogram is simplified from Giles ''et al.'', 2015:

References

External links

Ancient fossil may rewrite fish family tree
Viviane Callier. Jan. 12, 2015, 1:45 PM Prehistoric fish genera Fossil taxa described in 2015 Fossils of Russia Early Devonian animals Enigmatic vertebrate taxa {{Devonian-animal-stub