Tityosteus

Tityosteus Temporal range: Emsian PreꞒ Ꞓ O S D C P T J K Pg N
Artist's reconstruction of T. rieversi
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	†Placodermi
Order:	†Arthrodira
Suborder:	†Brachythoraci
Family:	†Homostiidae
Genus:	†Tityosteus Gross, 1960
Species:	†T. rieversi
Binomial name
†Tityosteus rieversi 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.[1] It attained a length of 2.5 meters.[2]

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.[1] 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 2.5 m (8.2 feet). 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.[1]

T. rieversi with a caudal fin 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,[1][3] or possessing fine denticles, like Antineosteus.[1] It has been suggested that Tityosteus probably was similar to the whale shark, in size, and habitat.[1]

Phylogeny

Tityosteus is part of the clade Migmatocephala, with other homostiids.

This cladogram is based on "FISH FROM THE EMSIAN OF ARAGÓN".[1]

	Taemasosteus
	Tityosteus Antineosteus Homostius

	Migmatocephala Eubrachythoraci

References

1. Mark-Kurik, E.; Carls, P. (2004). "Tityosteus, a marine fish (Arthrodira, Homostiidae) from the Emsian of Aragón, Spain, and its distribution" (PDF). Spanish Journal of Palaeontology. 19 (2). S2CID 218464633. Retrieved 2023-01-14.
2. Denison, Robert Howland (1978). Placodermi. München [Germany]. ISBN 978-0-89574-027-4.
3. Coatham, Samuel J.; Vinther, Jakob; Rayfield, Emily J.; Klug, Christian (2020-05-20). "Was the Devonian placoderm Titanichthys a suspension feeder?". Royal Society Open Science. 7 (5): 200272. Bibcode:2020RSOS....700272C. doi:10.1098/rsos.200272. PMC 7277245. PMID 32537223.