Janiosteus

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Janiosteus
Temporal range: Middle Devonian: Givetian, 387.7–382.7  Ma
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Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Placodermi
Order: Arthrodira
Suborder: Brachythoraci
Clade: Eubrachythoraci
Clade: Pachyosteomorphi
Superfamily: Dunkleosteoidea
Family: Panxiosteidae
Genus: Janiosteus
Ivanov, 1988
Type species
Janiosteus timanicus
Ivanov, 1989

Janiosteus is an extinct monospecific genus of placoderm arthrodire from the Middle Devonian: Late Givetian stage found in Timan, Russia.

Phylogeny

Janiosteus is a member of Panxiosteidae. In the 2010 Carr & Hlavin phylogenetic study, Panxiosteidae was recognized as the sister taxon to the family Dunkleosteidae, which together comprised the superfamily Dunkleosteoidea (one of the three major clades of Eubrachythoraci). [1] The phylogeny of Janiosteus within Panxiosteidae is shown in the cladogram below from the 2013 Zhu & Zhu study: [2]

Eubrachythoraci
Coccosteomorphi

Coccosteus cuspidatus

Harrytoombsia elegans

Mcnamaraspis kaprios

Incisoscutoidea

Compagopiscis croucheri

Incisoscutum ritchiei

Incisoscutum sarahae

Camuropiscidae

Latocamurus coulthardi

Camuropiscis laidlawi

Rolfosteus canningensis

Tubonasus lennardensis

Fallacosteus turneri

Aspinothoracidi

Dinichthys herzeri

Hadrosteus rapax

Gorgonichthys clarki

Heintzichthys gouldii

Selenosteidae

Stenosteus angustopectus

Gymnotrachelus hydei

Rhinosteus parvulus

Pachyosteus bulla

Dunkleosteoidea

Westralichthys uwagedensis

Protitanichthys rockportensis

Panxiosteidae

Panxiosteus ocullus

Janiosteus timanicus

Plourdosteus canadensis

Dunkleosteidae

Eastmanosteus calliaspis

Xiangshuiosteus wui

Eastmanosteus pustulosus

Kiangyousteus yohii

Golshanichthys asiatica

Dunkleosteus amblyodoratus

Dunkleosteus terrelli

Dunkleosteus raveri

Pachyosteomorphi

However, the subsequent 2016 Zhu et al. study using a larger morphological dataset recovered Panxiosteidae well outside of Dunkleosteoidea, instead within Coccosteomorphi and then Coccosteoidea as the sister group of Coccosteidae, as shown in the cladogram below: [3]

Eubrachythoraci
Coccosteomorphi
Coccosteoidea
Coccosteidae

Millerosteus minor

Coccosteus cuspidatus

Dickosteus threiplandi

Watsonosteus fletti

Protitanichthys rockportensis

Panxiosteidae

Plourdosteus canadensis

Panxiosteus ocullus

Janiosteus timanicus

Incisoscutoidea

Harrytoombsia elegans

Torosteus tuberculatus

Torosteus pulchellus

Mcnamaraspis kaprios

Compagopiscis croucheri

Trematosteus fontanellus

Camuropiscidae

Incisoscutum ritchiei

Incisoscutum sarahae

Rolfosteus canningensis

Tubonasus lennardensis

Fallacosteus turneri

Camuropiscis laidlawi

Latocamurus coulthardi

Pachyosteomorphi

Rhachiosteus pterygiatus

Dunkleosteoidea

Eastmanosteus calliaspis

Eastmanosteus pustulosus

Kiangyousteus yohii

Golshanichthys asiatica

Westralichthys uwagedensis

Dunkleosteus raveri

Dunkleosteus terrelli

Dunkleosteus amblyodoratus

Heterostiidae

Heterosteus ingens

Yinosteus major

Aspinothoracidi

Tapinosteus heintzi

Bullerichthys fascidens

Kendrickichthys cavernosus

Bruntonichthys multidens

Dinichthys herzeri

Hadrosteus rapax

Gorgonichthys clarki

Selenosteidae

Heintzichthys gouldii

Pachyosteus bulla

Gymnotrachelus hydei

Stenosteus angustopectus

Brachyosteus dietrichi

Melanosteus occitanus

Rhinosteus parvulus

Related Research Articles

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

Dinichthys is an extinct monospecific genus of giant, marine arthrodire placoderm from the Late Devonian, comparable in size, shape, and ecological role to the better-known Dunkleosteus. Fossils were recovered from the Ohio Shale Formation along the Olentangy River in Delaware County, Ohio.

Coccosteina Extinct order of fishes

Coccosteina is an extinct infraorder of placoderms, armored fish most diverse during the Devonian. However, the term is no longer in use, as modern cladistical methods have produced alternative phylogenetic trees of Brachythoraci with new subdivisions.

Dunkleosteidae 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>Eastmanosteus</i>

Eastmanosteus is a fossil genus of dunkleosteid placoderms. It was closely related to the giant Dunkleosteus, but differed from that genus in size, in possessing a distinctive tuberculated bone ornament, a differently shaped nuchal plate and a more zig-zagging course of the sutures of the skull roof.

<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.

<i>Mcnamaraspis</i>

Mcnamaraspis is an extinct monospecific genus of arthrodire placoderm that inhabited the ancient reef system of north Western Australia during the Frasnian epoch of the Late Devonian period. The type specimen was found and described by John A. Long from the Gogo Formation near Fitzroy Crossing. This fossil fish showed new anatomical features in arthrodires, like the well-preserved annular (ring-shaped) cartilages of the snout, previously inferred to be present by Erik Stensiö of Sweden. It is occasionally referred to as "The Gogo Fish" after the locale the holotype was excavated from.

Aspinothoracidi Extinct clade of fishes

Aspinothoracidi is a clade of placoderms, extinct armored fish most diverse during the Devonian. The gigantic apex predator Dinichthys, is the best-known member of this group. Many other genera, such as the infamous Dunkleosteus, were previously thought to be close relatives of Dinichthys and were grouped together in the family Dinichthyidae, though more recent studies have restricted that family to only its type species.

<i>Fallacosteus</i> Species of extinct placoderm

Fallacosteus is an extinct monospecific genus of arthrodire placoderm from the Early Frasnian stage of the Late Devonian period, found at the Gogo Formation of Kimberley, Western Australia. As with almost all other camuropiscids, F. turneri had an elongated snout that may have enhanced its hydrodynamic streamlining.

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

Xiangshuiosteus wui is an extinct monospecific genus of brachythoracid arthrodire placoderm from the Late Emsian stage of the Early Devonian epoch, discovered in Wuding County of Yunnan province, China. It has recently been reassessed as a dunkleosteid.

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

Kiangyousteus is an extinct monotypic genus of dunkleosteid from the Middle Devonian: Givetian aged Guanwu Formation in the Sichuan province of south-western China. The type species, Kiangyousteus yohii, was the first known arthrodire from Asia.

Dunkleosteoidea Extinct superfamily of fishes

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

Eubrachythoraci Extinct suborder of fishes

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 long-distance swimmers, leading to their widespread distribution beginning from at least the Middle Devonian period.

Pachyosteomorphi Extinct suborder of fishes

Pachyosteomorphi is an extinct clade of arthrodire placoderms within the Eubrachythoraci, armored fish most diverse during the Devonian. Most are considered to be pelagic long-distance swimmers, leading to their widespread distribution beginning from at least the Middle Devonian period.

Compagopiscis is an extinct genus of placoderm known from the Gogo Formation. It lived in the Upper Devonian of Western Australia. Compagopiscis is one of the earliest known vertebrates to have teeth. The genus is monotypic, with its only species being Compagopiscis croucheri.

Golshanichthys is an extinct monospecific genus of dunkleosteid from the Late Devonian: Frasnian stage from Kerman, Iran.

Westralichthys is an extinct monospecific genus of dunkleosteoid from the Late Devonian: Middle Famennian stage from Western Australia.

Panxiosteidae Extinct family of fishes

Panxiosteidae is an extinct family of arthrodire placoderms that lived during the Devonian period.

Panxiosteus is an extinct monospecific genus of placoderm arthrodire from the Middle Devonian: Givetian stage of Yunnan province, China.

Coccosteomorphi Extinct suborder of fishes

Coccosteomorphi is an extinct clade of arthrodire placoderms within the Eubrachythoraci, armored fish most diverse during the Devonian. Most are considered to be pelagic long-distance swimmers, leading to their widespread distribution beginning from at least the Middle Devonian period.

Torosteus is an extinct genus of arthrodire placoderm from the Early Frasnian stage of the Late Devonian period. Fossils are found in the Kimberley region of Australia.

References

  1. Carr, R.K.; Hlavin, W.J. (2010). "Two new species of Dunkleosteus Lehman, 1956, from the Ohio Shale Formation (USA, Famennian) and the Kettle Point Formation (Canada, Upper Devonian), and a cladistic analysis of the Eubrachythoraci (Placodermi, Arthrodira)". Zoological Journal of the Linnean Society . 159 (1): 195–222. doi: 10.1111/j.1096-3642.2009.00578.x .
  2. You-An Zhu; Min Zhu (2013). "A redescription of Kiangyousteus yohii (Arthrodira: Eubrachythoraci) from the Middle Devonian of China, with remarks on the systematics of the Eubrachythoraci". Zoological Journal of the Linnean Society . 169 (4): 798–819. doi: 10.1111/zoj12089 .
  3. Zhu, You-An; Zhu, Min; Wang, Jun-Qing (1 April 2016). "Redescription of Yinostius major (Arthrodira: Heterostiidae) from the Lower Devonian of China, and the interrelationships of Brachythoraci". Zoological Journal of the Linnean Society . 176 (4): 806–834. doi: 10.1111/zoj.12356 . ISSN   0024-4082.