Last updated

Temporal range: Famennian
Titanichthys clarkii reconstruction.png
Rendered reconstruction of Titanichthys clarkii
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Placodermi
Order: Arthrodira
Suborder: Brachythoraci
Superfamily: Dinichthyloidea
Family: Titanichthyidae
Dean, 1901
Genus: Titanichthys
Newberry, 1885
Type species
Titanichthys agassizi
Newberry, 1885
  • T. agassiziNewberry, 1887
  • T. clarkiNewberry, 1887
  • T. attenuatusWright in Claypole, 1893
  • T. hussakofiHay, 1930
  • T. termieriLehman, 1954
  • T. ?koslowskiiKulczycki, 1957

Claypole, 1894

Titanichthys is an extinct genus of giant, aberrant marine placoderm from shallow seas of the Late Devonian of Morocco, Eastern North America, and possibly Europe. [1] Many of the species approached Dunkleosteus in size and build. Unlike its relative, however, the various species of Titanichthys had small, ineffective-looking mouth-plates that lacked a sharp cutting edge. It is assumed that Titanichthys was a filter feeder that used its capacious mouth to swallow or inhale schools of small, anchovy-like fish, or possibly krill-like zooplankton, and that the mouth-plates retained the prey while allowing the water to escape as it closed its mouth. A study has since confirmed this assumption as its jaws are functionally closer to that of filter feeders like baleen whales and basking sharks, and it appears to have developed from benthic durophagists that became pelagic suspension feeders. This would make it the first (known) large-sized vertebrate filter feeder. [2] Titanichthys was estimated to have reached a length of 7–7.6 m (23–25 ft), [3] [4] [5] but Engelman (2023) suggested that Titanichthys was comparable in size to Dunkleosteus, likely measuring about or just over 4.1 metres (13.5 ft) in length. [6]



Titanichthys is thought to have been a basal aspinothoracid, closest related to Bungartius and Tafilalichthys. [7]

Rhachiosteus pterygiatus

Tapinosteus heintzi

Trematosteus fontanellus

Bruntonichthys multidens

Kendrickichthys cavernosus

Bullerichthys fascidens

Dinichthys herzeri

Hadrosteus rapax


Gorgonichthys clarki

Heintzichthys gouldii



Tafilalichthys lavocati

Bungartius perissus


Titanichthys agassizi

Titanichthys cf. clarki


The genus shows a great diversity in the Famennian-aged Cleveland Shale, though species are also found in similarly aged strata in Morocco and possibly the Holy Cross Mountains in Poland. [1]

T. agassizi

This is the type species, from the Cleveland Shale. Its infrognathals are strongly recurved medially, and is elongated with a spatula-like process at the anterior end. The headshield averages about 60 cm (24 in) in length. [1]

T. attenuatus

This Cleveland Shale species is based on an infragnathal bone more than 36 cm (14 in) in length. May possibly be a synonym of T. agassizi. [8]

T. clarkii

This Cleveland Shale species has infragnathals that are not as recurved as T. agassizi's. The cranial roof is comparatively narrower and more rounded. It is the largest known species in the genus, and possibly one of the largest Devonian vertebrates known. The head is about 90 cm (35 in) in length. [8]

Fossil head shield of Titanichthys clarkii Titanichthys.jpg
Fossil head shield of Titanichthys clarkii

T. hussakofi

This Cleveland Shale species is known from a badly preserved, incomplete infragnathal. It was originally described by Claypole as "Brontichthys clarki" in 1894. [8] As "Brontichthys" is a junior synonym of Titanichthys, it should not be confused with another, similarly-named arthrodire, Bruntonichthys of Dunkleosteidae.

T. rectus

This Cleveland Shale species has an infragnathal as large as that of T. clarkii, though T. rectus' infragnathal is much straighter, and does not have a spatula-like process on its anterior end. [8]

T. kozlowskii

This species placement within the genus is in doubt. It is based on incomplete nuchal and central plates found in Upper Famennian-aged marine strata of the Holy Cross Mountains in Poland. [8]

T. termieri

This species is found in Lower Famennian-aged marine strata of Tafilalet, Southern Morocco. The fossil material of this species strongly suggests it is as large as the Cleveland Shale' T. clarkii. [8] The average combined length of the head and trunk shields for T. termieri is estimated to be 200 cm (79 in) [8] When the first fossils of T. termieri were found by geologist Henri Termier, the specimens were originally placed within the genus Gorgonichthys - that is, after Termier was able to convince his colleagues that the bone scraps were of a placoderm, and not a dinosaur. [9]

Related Research Articles

<span class="mw-page-title-main">Placodermi</span> Class of fishes (fossil)

Placodermi is a class of armoured prehistoric fish, known from fossils, which lived from the Silurian to the end of the Devonian period. Their head and thorax were covered by articulated armoured plates and the rest of the body was scaled or naked, depending on the species. Placoderms were among the first jawed fish; their jaws likely evolved from the first of their gill arches.

<i>Dunkleosteus</i> Genus of extinct fishes

Dunkleosteus is an extinct genus of large arthrodire ("jointed-neck") fish that existed during the Late Devonian period, about 382–358 million years ago. It was a pelagic fish inhabiting open waters, and one of the first apex predators of any ecosystem.

<i>Groenlandaspis</i> Genus of fishes (fossil)

Groenlandaspis is an extinct genus of arthrodire from the Late Devonian. Fossils of the different species are found in late Devonian strata in all continents except eastern Asia. The generic name commemorates the fact that the first specimens of the type species were found in Greenland.


Coccosteus is an extinct genus of arthrodire placoderm from the Devonian period. Its fossils have been found throughout Europe and North America. The majority of these have been found in freshwater sediments, though such a large range suggests that they may have been able to enter saltwater. It was a small placoderm, with Coccosteus cuspidatus measuring 29.6–43.9 cm (11.7–17.3 in) long.

<i>Dinichthys</i> Extinct genus of placoderm fish

Dinichthys is an extinct monospecific genus of large marine arthrodire placoderm from the Late Devonian measuring around 3 metres (9.8 ft) long. Fossils were recovered from the Ohio Shale Formation along the Olentangy River in Delaware County, Ohio.

<span class="mw-page-title-main">Dunkleosteidae</span> Extinct family of fishes

Dunkleosteidae is an extinct family of arthrodire placoderms that lived during the Devonian period. The gigantic apex predator Dunkleosteus terrelli is the best known member of this group.

<i>Holonema</i> Extinct genus of fishes

Holonema is an extinct genus of relatively large, barrel-shaped arthrodire placoderms that were found in oceans throughout the world from the Mid to Late Devonian, when the last species perished in the Frasnian-Fammian extinction event. Most species of the genus are known from fragments of their armor, but the Gogo Reef species, H. westolli, is known from whole, articulated specimens.

<i>Gorgonichthys</i> Genus of fishes (fossil)

Gorgonichthys is extinct monospecific genus of large arthrodire placoderm. Fossils are found in the Upper Famennian Cleveland Shales of Late Devonian in Ohio. The type species is Gorgonichthys clarki.

<i>Holdenius</i> Extinct genus of fishes

Holdenius is an extinct genus of arthrodire placoderm fish which lived during the Late Devonian period.

<i>Plourdosteus</i> Extinct genus of fishes

Plourdosteus is an extinct genus of placoderm arthrodire which was relatively widespread in Euramerica during the Givetian to Frasnian ages of the Devonian. It was a small placoderm, with P. canadensis measuring 37.5–51.4 cm (14.8–20.2 in) long.

<span class="mw-page-title-main">Hadrosteidae</span>

Hadrosteidae is a family of arthrodire placoderms from the Late Devonian. It was originally erected for the late Frasnian Hadrosteus, from the Kellwasserkalk facies. Later, the family was subjectively subsumed into Dinichthyidae due to Hadrosteus' anatomical similarities with Dunkleosteus and Dinichthys. In 1967, Obruchev placed the enigmatic arthrodire incertae sedisDiplognathus, from the Eastern American Famennian, within Hadrosteidae, on the basis of how the two genera have similar denticle ("teeth") patterns of the inferognathals, though, Denison (1978) contests this placement. With the redefining of Dinichthyidae as a monotypic family for Dinichthys, and only a few other genera placed within Dunkleosteidae, Hadrosteidae is now seen as a valid family again.

<i>Stenosteus</i> Genus of fishes (fossil)

Stenosteus is an extinct monospecific genus of medium-sized selenosteid arthrodire placoderms of the Late Devonian period known from the Upper Famennian Cleveland Shale of Ohio. Estimated skull lengths range from 6 to 9 centimeters Most fossils of Stenosteus have been scraps of armor and portions of tooth-plates suggestive of Selenosteus. In 1996, enough material of a new species, S. angustopectus, was recovered to allow a reconstruction of armor that resembles that of Selenosteus.

<i>Gymnotrachelus</i> Genus of fishes (fossil)

Gymnotrachelus is an extinct monospecific genus of large selenosteid arthrodire placoderm of the Late Devonian known from the Late Famennian Cleveland Shale of Ohio. The type species Gymnotrachelus hydei was originally reconstructed as physically resembling Selenosteus, with slightly smaller orbits. Later specimens led to a reappraisal, and now G. hydei is thought to have a more gar-like or barracuda-like build.


Diplognathus is a genus of arthrodire placoderm from the Late Famennian Cleveland Shale of Late Devonian Ohio, known only from incomplete fragments of jaws and skulls. What fragments are known suggest that the living animals were large-eyed piscivores with weak, but widely gaping jaws. D. mirabilis is thought to be fairly large, with infragnathals up to 45 centimeters in length. The second species, D. larfargei, was much smaller, with inferognathals averaging about 4 centimeters in length.

<span class="mw-page-title-main">Homostiidae</span>

Homostiidae is a family of flattened arthrodire placoderms from the Early to Middle Devonian. Fossils appear in various strata in Europe, Russia, Morocco, Australia, Canada and Greenland.


Heterosteus is an extinct genus of heterosteid placoderm of the Middle Devonian known from remains discovered in Europe and Greenland. According to Denison, 1978, Heterosteus might have been planktivorous, along with Homosteus, and Titanichthys.

<i>Africanaspis</i> Extinct genus of placoderm from Late Devonian South Africa

Africanaspis is an extinct genus of groenlandaspidid placoderm known from two species, Africanaspis doryssa, named in 1997 from fossils discovered in South Africa and Africanaspis edmountaini, named from fossils described from South Africa during 2017. A. edmountaini is only known from juvenile specimens. Both species are known from the Witpoort Formation. A. doryssa is estimated to have been 23–24.5 cm (9.1–9.6 in) long.

<i>Millerosteus</i> Extinct genus of placoderm fish of the Devonian period

Millerosteus is an extinct genus of coccosteid arthrodire placoderm from the Early Givetian stage of the Middle Devonian period. Fossils are found in the Orkneys and Caithness, Scotland. It was a small placoderm with an body length of 14 cm (5.5 in). Millerosteus is one of the few arthrodires known from specimens preserving the entire skeleton.


Watsonosteus is an extinct genus of coccosteid arthrodire placoderm from the Late Givetian stage of the Middle Devonian period. Fossils are found in the Orkney Islands, Scotland. It was a small placoderm with an total body length of 57 cm (22 in), with the largest individuals reaching lengths of 1 m (39 in). It is one of the few arthrodires for which complete body fossils are known.

<i>Amazichthys</i> Extinct genus of armored fish

Amazichthys is an extinct genus of selenosteid arthrodire from the Middle Famennian of the Late Devonian of the Anti-Atlas Mountains of Morocco. It contains a single species, Amazichthys trinajsticae. It is one of a few example of placoderm known from whole body shape, including cartilaginous axial and fin elements.


  1. 1 2 3 Denison, Robert (1978). Placodermi Volume 2 of Handbook of Paleoichthyology'. Stuttgart New York: Gustav Fischer Verlag. p. 100. ISBN   978-0-89574-027-4.
  2. Coatham, Samuel J.; Vinther, Jakob; Rayfield, Emily J.; Klug, Christian (2020). "Was the Devonian placoderm Titanichthys a suspension feeder?". Royal Society Open Science. 7 (5): 200–272. Bibcode:2020RSOS....700272C. doi:10.1098/rsos.200272. PMC   7277245 . PMID   32537223.
  3. Bulletin 70. Ohio. Division of Geological Survey. 1996. p. 290. Retrieved 2022-08-28.
  4. Charlie Underwood, Martha Richter, Zerina Johanson (2019). Evolution and Development of Fishes. Cambridge University Press. p. 13. ISBN   9781107179448 . Retrieved 1 September 2022.{{cite book}}: CS1 maint: multiple names: authors list (link)
  5. Bashford Dean (1895). Fishes, Living and Fossil: An Outline of Their Forms and Probable Relationships. Macmillan and Company. p. 130. Retrieved 2022-08-28.
  6. Engelman, Russell K. (2023). "A Devonian Fish Tale: A New Method of Body Length Estimation Suggests Much Smaller Sizes for Dunkleosteus terrelli (Placodermi: Arthrodira)". Diversity. 15 (3). 318. doi: 10.3390/d15030318 .
  7. Boyle, James; Ryan, Michael J. (March 2017). "New information on Titanichthys (Placodermi, Arthrodira) from the Cleveland Shale (Upper Devonian) of Ohio, USA". Journal of Paleontology. 91 (2): 318–336. doi: 10.1017/jpa.2016.136 . ISSN   0022-3360. S2CID   132831650.
  8. 1 2 3 4 5 6 7 Denison, Robert (1978). Placodermi Volume 2 of Handbook of Paleoichthyology'. Stuttgart New York: Gustav Fischer Verlag. p. 101. ISBN   978-0-89574-027-4.
  9. See Janvier (1998) p.323 for details.


Further reading