''Edenopteron'' is a genus of large

tristichopterid Tristichopterids (Tristichopteridae) were a diverse and successful group of tetrapodomorph fishes living throughout the Middle and Late Devonian. They first appeared in the Eifelian stage of the Middle Devonian. Within the group sizes ranged from ...

fish from the

Late Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...

(

Famennian The Famennian is the latter of two faunal stages in the Late Devonian Epoch. The most recent estimate for its duration estimates that it lasted from around 371.1 million years ago to 359.3 million years ago. An earlier 2012 estimate, still used ...

) of what is now southeastern Australia. It is known from a single specimen of a single species, ''E. keithcrooki'', described in 2013.

Discovery

Skull and shoulder-girdle restorations of Tristichopterids

''Edenopteron keithcrooki'' is known from remains excavated from the Worange Point Formation, near the town of

Eden Eden may refer to: * Garden of Eden, the "garden of God" described in the Book of Genesis Places and jurisdictions Canada * Eden, Ontario * Eden High School Middle East * Eden, Lebanon, a city and former bishopric * Camp Eden, Iraq O ...

on the coast of

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

in 2008. The

species name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bo ...

is a combination of the name Eden and ''pteron'', meaning wing or fin in

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

. The specific name honors Dr.

Keith Crook Keith Alan Waterhouse Crook (3 August 1933 - 18 February 2020) was an Australian geologist and Clarke Medalist. Education Keith Crook attended Newington College (1944-1949) and the University of Sydney from whence he graduated as a Bachelor of ...

of the

Australian National University The Australian National University (ANU) is a public research university located in Canberra, the capital of Australia. Its main campus in Acton encompasses seven teaching and research colleges, in addition to several national academies and ...

for his discovery of several fossil sites in New South Wales and his key role in helping to map the geology around Eden.

Description

The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

consists of numerous semi-articulated remains, including an incomplete

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, t ...

roof, snout,

palate The palate () is the roof of the mouth in humans and other mammals. It separates the oral cavity from the nasal cavity. A similar structure is found in crocodilians, but in most other tetrapods, the oral and nasal cavities are not truly s ...

, cheeks, lower jaws and associated

dermal bones A dermal bone or investing bone or membrane bone is a bony structure derived from intramembranous ossification forming components of the vertebrate skeleton including much of the skull, jaws, gill covers, shoulder girdle and fin spines rays ( lepi ...

, a left

shoulder girdle The shoulder girdle or pectoral girdle is the set of bones in the appendicular skeleton which connects to the arm on each side. In humans it consists of the clavicle and scapula; in those species with three bones in the shoulder, it consists ...

, and assorted

scales Scale or scales may refer to: Mathematics * Scale (descriptive set theory), an object defined on a set of points * Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original * Scale factor, a number ...

. Reconstructions suggest a skull length of 30 cm (12 in) and lower jaw length of about 48 cm (19 in). The

endoskeleton An endoskeleton (From Greek ἔνδον, éndon = "within", "inner" + σκελετός, skeletos = "skeleton") is an internal support structure of an animal, composed of mineralized tissue. Overview An endoskeleton is a skeleton that is on the ...

shows a large or complete lack of

ossification Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in ...

. The

orbits In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as a ...

(eye-sockets) are somewhat triangular rather than oval-shaped. ''Edenopteron'' possessed

dentary In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone ...

fangs and

premaxillary The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...

tusks, which are presumed to be

derived trait In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to have ...

s for other large tristichopterids. By comparison to body size ratios of other tristichopterid fishes (e.g. ''

Eusthenodon ''Eusthenodon'' (Greek for “strong-tooth” – ''eustheno''- meaning “strength”, -''odon'' meaning “tooth”) is an extinct genus of tristichopterid tetrapodomorphs from the Late Devonian period, ranging between 383 and 359 million yea ...

'', '' Langlieria'', ''

Mandageria ''Mandageria fairfaxi'' (Pronunciation: Man-daj-ee-ree-a fair-fax-i) is an extinct lobe-finned fish that lived during the Late Devonian period (Frasnian – Famennian). It is related to the much larger ''Hyneria''; although ''Mandageria'' was sm ...

''), the body length of ''Edenopteron'' is estimated at 2.9—3.2 m (9.5—10.5 ft). Additional fossil material may be described in the future: according to lead researcher Gavin Young, quoted in the

Canberra Times ''The Canberra Times'' is a daily newspaper in Canberra, Australia, which is published by Australian Community Media. It was founded in 1926, and has changed ownership and format several times. History ''The Canberra Times'' was launched in ...

: "We know that part of the pectoral girdle is still in the rock, so if we can lift up a few more blocks, we might find that the body is actually preserved in the rock."

Classification

''Edenopteron'' is assigned to the

Gondwanan Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...

tristichopterid subfamily Mandageriinae due to similarities shared with ''

Cabonnichthys ''Cabonnichthys'' ("Burns' Cabonne fish") is an extinct genus of tristichopterid fish that lived in the Late Devonian period (Famennian The Famennian is the latter of two faunal stages in the Late Devonian Epoch. The most recent estimate fo ...

'' and ''

'', including paired

vomer The vomer (; lat, vomer, lit=ploughshare) is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxil ...

s in the palate, submandibular bones overlapping ventral jaw margin, and scales ornamented with widely-spaced grooves.

References

External links

Local dig uncovers new species of ancient fish
ANU Media Release
Fang the fish shocks researchers
''The Australian'' {{Taxonbar, from=Q15720781 Tristichopterids Prehistoric lobe-finned fish genera Late Devonian animals Late Devonian fish Prehistoric fish of Australia Paleontology in New South Wales Fossil taxa described in 2013