Tityosteus

{{Speciesbox

| fossil_range = {{Geological range| Emsian}}

| image = Tityosteus rieversi.jpg

| image_caption = Artist's reconstruction of T. rieversi

| parent_authority = Gross, 1960

| genus = Tityosteus

| species = rieversi

| authority = Gross, 1960

}}

Tityosteus is an extinct genus of homostiid arthrodire from the Early Emsian of the Early Devonian, with fossils known from Germany, the Ibero-Armorican Trough, and southern Siberia.{{Cite journal|last1=Mark-Kurik |first1=E. |last2=Carls |first2=P. |date=2004 |title=Tityosteus, a marine fish (Arthrodira, Homostiidae) from the Emsian of Aragón, Spain, and its distribution.|journal=Spanish Journal of Palaeontology|volume=19|number=2|page=|url=http://sepaleontologia.es/revista/anteriores/REP19_2004/NUM_2/REP2004_19_2_02.pdf |access-date=2023-01-14 |s2cid=218464633 |language=en}} It attained a length of 2.5 meters.{{Cite book |last=Denison |first=Robert Howland |url=https://books.google.com/books?id=syALAQAAIAAJ&q=2.5+ |title=Placodermi |date=1978 |publisher=München [Germany] |isbn=978-0-89574-027-4 |language=en}}

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 {{Convert|2.5|m|ft|abbr=in}}. 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 arthrodire), being from similar facies as Tityosteus (Eifelian of Aragón, Spain), it may have been pelagic, and able to cross open waters.

File:Tityosteus rieversi as a pelagic filter feeder.jpeg capable of efficient open-ocean crossing, whilst being a filter feeder, as suggested for homostiids.]]

Diet

While the inferognathals of Tityosteus have not been found, they could be either "toothless", like Homosteus, which has been suggested to be planktivorous,{{Cite journal |last1=Coatham |first1=Samuel J. |last2=Vinther |first2=Jakob |last3=Rayfield |first3=Emily J. |last4=Klug |first4=Christian |date=2020-05-20 |title=Was the Devonian placoderm Titanichthys a suspension feeder? |journal=Royal Society Open Science |volume=7 |issue=5 |pages=200272 |doi=10.1098/rsos.200272 |pmc=7277245 |pmid=32537223|bibcode=2020RSOS....700272C }} or possessing fine denticles, like Antineosteus. It has been suggested that Tityosteus probably was similar to the whale shark, in size, and habitat.