''Tityosteus'' is an extinct genus of homostiid

arthrodire Arthrodira (Greek for "jointed neck") is an Order (biology), order of extinct armored, jawed fishes of the class Placodermi that flourished in the Devonian period before their sudden extinction, surviving for about 50 million years and penetratin ...

from the Early Emsian of the

Early Devonian The Early Devonian is the first of three Epoch (geology), epochs comprising the Devonian period, corresponding to the Lower Devonian Series (stratigraphy), series. It lasted from and began with the Lochkovian Stage , which was followed by the Pr ...

, with fossils known from

Germany Germany, officially the Federal Republic of Germany, is a country in Central Europe. It lies between the Baltic Sea and the North Sea to the north and the Alps to the south. Its sixteen States of Germany, constituent states have a total popu ...

, the Ibero-Armorican Trough, and southern

Siberia Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states ...

. It attained a length of 2.5 meters.

Description

''Tityosteus'' has only an 11 cm right marginal plate known, and margin ends and parts, in addition to the central plate overlap area being broken. However, Denison, 1978 said that it had a nuchal, attaining a length of 25 cm. The book also estimates T. rieversi of reaching lengths of . According to "Tityosteus, A MARINE FISH (ARTHRODIRA, HOMOSTIIDAE) FROM THE EMSIAN OF ARAGÓN, SPAIN, AND ITS DISTRIBUTION", given Tityosteus's distribution, and Carolowilhelma (a

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

), being from similar facies as Tityosteus (

Eifelian The Eifelian is the first of two faunal stages in the Middle Devonian Epoch. It lasted from 393.3 ± 1.2 million years ago to 387.7 ± 0.8 million years ago. It was preceded by the Emsian Stage and followed by the Givetian Stage. North American ...

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), it may have been

, and able to cross open waters. Tityosteus rieversi as a pelagic filter feeder

Diet

While the inferognathals of ''Tityosteus'' have not been found, they could be either "toothless", like ''

Homosteus ''Homosteus'' (also commonly spelled ''Homostius'') is a genus of flattened arthrodire placoderm from the Middle Devonian. Fossils are found primarily in Eifelian-epoch aged strata of Europe, Canada, Greenland, and Estonia. All of the species h ...

'', which has been suggested to be

planktivorous A planktivore is an aquatic organism that feeds on planktonic food, including zooplankton and phytoplankton. Planktivorous organisms encompass a range of some of the planet's smallest to largest multicellular animals in both the present day and i ...

, or possessing fine denticles, like ''

Antineosteus References {{Arthrodira, state=E. {{Taxonbar, from=Q21416371 Homostiidae Arthrodire genera Placoderms of Africa Placoderms of Europe ...

''. It has been suggested that ''Tityosteus'' probably was similar to the

whale shark The whale shark (''Rhincodon typus'') is a slow-moving, filter feeder, filter-feeding carpet shark and the largest known Extant taxon, extant fish species. The largest confirmed individual had a length of . The whale shark holds many records for ...

, in size, and habitat.

Phylogeny

''Tityosteus'' is part of the clade

Migmatocephala Migmatocephala is a clade of placoderm fish within the suborder Brachythoraci. Migmatocephala includes the homostiids Taemasosteus?, '' Tityosteus'', ''Antineosteus'', '' Atlantidosteus'', and '' Homosteus''. Phylogeny The cladogram A ...

, with other homostiids. This cladogram is based on "FISH FROM THE EMSIAN OF ARAGÓN". {{Clade, style={{Clade , 1=''

Taemasosteus ''Taemasosteus'' is an extinct genus of arthrodire placoderm. Its fossils have been found in Emsian-aged marine strata in New South Wales, Australia. It contains two species, ''T. novaustrocambricus'', and ''T. maclartiensis''. The genus (and a ...

'' , 2={{Clade , 1=''Tityosteus'' , 2={{Clade , 1=''

Antineosteus References {{Arthrodira, state=E. {{Taxonbar, from=Q21416371 Homostiidae Arthrodire genera Placoderms of Africa Placoderms of Europe ...

'' , 2='' Homostius'' {{Clade, style=, 1={{Clade , 1=''

'' , label2=

Eubrachythoraci Eubrachythoraci is an extinct clade of arthrodire placoderms within the suborder Brachythoraci, armored fish most diverse during the Devonian. Most are considered to be pelagic (open ocean) long-distance swimmers, leading to their widespread dis ...

, 2={{Clade

References

{{Reflist {{Arthrodira, A. {{Taxonbar, from=Q116199597 Fossil taxa described in 1960 Devonian Europe Emsian genera Arthrodire genera Arthrodires Placoderms of Europe Placoderms of Asia