| Eastmanosteus Temporal range: Middle Devonian |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Placodermi |
| Order: | Arthrodira |
| Suborder: | Dinichthyoidea |
| Family: | Dinichthyidae |
| Genus: | Eastmanosteus |
| Type species | |
| Eastmanosteus pustulosus (Eastman 1897) |
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Eastmanosteus ("Eastman's bone shield") is a fossil genus of dinichthyid placoderms. It was closely related to the giant Dunkleosteus, but differed from that genus 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.[1]
Species of Eastmanosteus had powerful jaws with sharp cutting edges and were likely active predators. Fossils have been found in many parts of the world in marine sediments dating from the Middle to Late Devonian. They were medium-to-large fish, with specimens E. pustulosus and E. licharevi approaching a total length of 3 metres. Complete exoskeletons with soft-tissue traces of E. calliaspis from Australia make this one of the best known dinichthyids.
From the Frasnian Gogo Formation of northwestern Western Australia. This is the best known member of the genus with many articulated skulls and trunk armours in museum collections.[2] Evidence of muscle fibres, circulatory structures and nerve tissue have been preserved representing some of the oldest known gnathostome soft tissue.[3] The largest known skull is 272mm in length suggesting a total size of roughly 1.5m. It was one of the largest fish in the Gogo assemblage.[4]
A poorly known species from Russia, originally described from an isolated nuchal plate from the Frasnian of Timman with additional material from the Famennian of Lipetsk.[5]
A medium sized species from the Eifelian of south-central Manitoba, Canada. One of the earliest and most completely known members of the genus.[6]
Based on a single almost complete head shield from the Late Devonian of New York State, USA. Has previously been assigned to Dinicthys and Dunkleosteus.[7]
This is the type species and was originally placed in the genus Dinichthys. It was a large and widely distributed form, with fossil material from the Middle-Late Devonian of the USA (Wisconsin, Iowa, Michigan, New York State) and the Frasnian of Poland.[8]
Originally assigned to Dunkleosteus. From the Middle Devonian of Yunnan Province, China.[9]
An undescribed species based on relatively well preserved material from the Frasnian of Kerman, East Iran.[10]
Morocco, and the USA. Most of these are either indeterminate dinichthyids or are now placed in different genera.[11]
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