Dunkleosteidae

Dunkleosteidae Temporal range: Late Emsian to Late Famennian, ~
Dunkleosteus terrelli skull, Queensland Museum
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	†Placodermi
Order:	†Arthrodira
Suborder:	†Brachythoraci
Clade:	†Eubrachythoraci
Clade:	†Pachyosteomorphi
Superfamily:	†Dunkleosteoidea
Family:	†Dunkleosteidae Stensiö, 1963
Type species
Dinichthys terrelli Newberry, 1873
Genera
Dunkleosteus Eastmanosteus Golshanichthys Heterosteus Kiangyousteus Xiangshuiosteus?

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.

Phylogeny

While members of Dunkleosteidae were previously thought to be close relatives of the genus Dinichthys (when they were not synonymized as each other) and grouped together in the family Dinichthyidae, more recent phylogenetic studies have shown that the two taxa represent two very distinct clades within Arthrodira. Dunkleosteidae was then established as the sister taxon to the family Panxiosteidae, which together comprised the superfamily Dunkleosteoidea (one of the three major clades of Eubrachythoraci). Dunkleosteidae was thus cladistically defined as including the type genus Dunkleosteus and all other genera in Dunkleosteoidea more closely related to Dunkleosteus than to Panxiosteus.

The phylogeny of Dunkleosteidae from the 2013 Zhu & Zhu study is shown in the cladogram below:

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, leaving the status of Dunkleosteidae as a clade grouping separate from Dunkleosteoidea in doubt, as shown in the cladogram below:

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

Genera

Dunkleosteus

Restoration of D. terrelli

The type genus, Dunkleosteus, is known from Late Frasnian and Famennian-aged marine strata from Europe, Morocco, and North America. The best known species, D. terrelli, is famous as the "world's first vertebrate apex predator," and is estimated to be up to 6 m (20 ft) in length: other species, however, such as D. raveri, are estimated to be 1 m (3.3 ft) in length.

Eastmanosteus

Eastmanosteous is a diverse genus of medium to somewhat large predatory arthrodires very similar in anatomy to the species of Dunkleosteus. Eastmanosteus differs from Dunkleosteus in having a unique tubercle-ornamentation on the dermal surfaces of the plates, a distinctively shaped nuchal plate, and sutures that are more zigzagging. The best studied species, E. calliaspis may not be of this genus due to its recently appreciated relationship to the Emsian-aged genus Xiangshuiosteus.

Golshanichthys

Fossils of Golshanichthys are found in Frasnian-aged marine strata near Kerman, Iran.

Heterosteus

Heterosteus is from the middle Devonian, found in Europe and Greenland. It is one of the larger members of the family, with an estimated body length of up to 6 metres (20 ft).

Kiangyousteus

Kiangyousteus yohii

This Middle Devonian genus represents the first arthrodire described from China. Fossils are known from the Late Givetian to Early Frasnian-aged Guanwu Formation in Sichuan province.

Xiangshuiosteus

Xiangshuiosteus was originally described as an arthrodire incertae sedis of the Late Emsian with anatomical features suggestive of both buchanosteids and coccosteids. With the reappraisal of Kiangyousteus, it is now thought to be a dunkleosteid most closely related to Eastmanosteus calliaspis.