Biology:Dunkleosteidae

Short description: Extinct family of fishes

Dunkleosteidae Temporal range: Late Emsian to Late Famennian, ~393.3–358.9 Ma PreЄ Є O S D C P T J K Pg N
Dunkleosteus terrelli skull, Queensland Museum
Scientific classification
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.

References

Wikidata ☰ Q5315394 entry