''Wladysagitta'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of osteostracan

jawless fish Agnatha (; ) or jawless fish is a paraphyletic infraphylum of animals in the subphylum Vertebrata of the phylum Chordata, characterized by the lack of jaws. The group consists of both extant taxon, living (Cyclostomi, cyclostomes such as hagfish ...

that existed during the lower Devonian period of what is now

Podolia Podolia or Podillia is a historic region in Eastern Europe located in the west-central and southwestern parts of Ukraine and northeastern Moldova (i.e. northern Transnistria). Podolia is bordered by the Dniester River and Boh River. It features ...

Ukraine Ukraine is a country in Eastern Europe. It is the List of European countries by area, second-largest country in Europe after Russia, which Russia–Ukraine border, borders it to the east and northeast. Ukraine also borders Belarus to the nor ...

. This taxon was named in honor of Polish paleontologist Dr. Władysław Zych (1899–1981), and from the Latin sagitta, meaning arrow, which is in reference to the arrow-like shape of its skull.Voichyshyn, Victor. (2006). New osteostracans from the Lower Devonian terrigenous deposits of Podolia, Ukraine. Acta Palaeontologica Polonica. 51.

Description

''Wladysagitta'', like other osteostracans, possesses very advanced features for an agnathan; namely, an armored headshield with complicated cranial anatomy, paired fins and rows of plated scales. It is remarkable among osteostracans for possessing a rostral process, a beaklike structure unusual for this class, which usually possesses blunted, horseshoe-shaped headshields. It is also distinct for being ornamented by a number of unusually prominent, thornlike tubercles on its headshield as preserved in some specimens. Like its relatives, its flat, spade-like head, dorsally orientated eye sockets and lack of jaws indicate that it was probably a

benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ...

, bottom-feeding animal, and given its taxonomic placement, it likely made its home in marine environments. ''Wladysagitta'' is relatively small in size compared to other osteostracans. The headshield of the holotype is around long and approximately the same in width, though slightly larger specimens do exist. Wladysagitta janvieri

Species

This genus includes only two described species: ''W. janvieri'' and ''W. acutirostris''. The type species, ''W. janvieri'', is comparatively larger, broader and has a more pronounced rostral structure, whereas ''W. acutirostris'' is slightly smaller, narrower and has a more blunted headshield shape. The two species have similar headshield curvatures and, due to the poorly preserved rostral process of ''W. acutirostris'', the differences between them are still somewhat unclear.

References

{{Taxonbar, from=Q107210134 Osteostraci genera