''Edenopteron'' is a genus of large tristichopterid fish from the

Late Devonian The Devonian ( ) is a geologic period and system of the Paleozoic era during the Phanerozoic eon, spanning 60.3 million years from the end of the preceding Silurian period at million years ago ( Ma), to the beginning of the succeeding ...

(

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

) of what is now southeastern

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. 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 on the coast of

New South Wales New South Wales (commonly abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east coast of :Australia. It borders Queensland to the north, Victoria (state), Victoria to the south, and South ...

in 2008. The generic name is a combination of the name Eden and ''pteron'', meaning wing or fin in

Greek Greek may refer to: 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 of all kno ...

. The specific name honors Dr. Keith Crook of the

Australian National University The Australian National University (ANU) is a public university, public research university and member of the Group of Eight (Australian universities), Group of Eight, located in Canberra, the capital of Australia. Its main campus in Acton, A ...

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 (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

consists of numerous semi-articulated remains, including an incomplete

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

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 sep ...

, 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, fin rays (lepidotrichia) ...

, 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 o ...

, 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 Ancient Greek ἔνδον, éndon = "within", "inner" + σκελετός, skeletos = "skeleton") is a structural frame (skeleton) — usually composed of mineralized tissue — on the inside of an animal, overlaid by soft ...

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 t ...

. The

orbits In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an physical body, object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an satellite, artificia ...

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

dentary In jawed vertebrates, the mandible (from the Latin ''mandibula'', 'for chewing'), lower jaw, or jawbone is a bone that makes up the lowerand typically more mobilecomponent of the mouth (the upper jaw being known as the maxilla). The jawbone ...

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 mammals 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 ha ...

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

Eusthenodon ''Eusthenodon'' (Greek for “strong-tooth” – ''eusthenes''- meaning “strong”, -''odon'' meaning “tooth”) is an extinct genus of marine tristichopterid tetrapodomorphs from the Devonian, Late Devonian period, ranging between 365 and 3 ...

'', ''

Langlieria ''Langlieria'' is a genus of prehistoric sarcopterygian (lobe-finned "fish"), from the end of the Devonian period (Famennian). It was discovered in Belgium and Pennsylvania Pennsylvania, officially the Commonwealth of Pennsylvania, is a ...

'', ''

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 sma ...

''), the body length of ''Edenopteron'' is estimated at 2.9—3.2 m (9.5—10.5 ft), while study in 2023 estimates length up to . 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 1 ...

: "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, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia, Zealandia, Arabia, and the ...

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) of Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland ...

'' and ''

'', including paired

vomer The vomer (; ) 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 maxillary bones. The vomer forms ...

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 Tristichopteridae Prehistoric lobe-finned fish genera Late Devonian sarcopterygians Devonian sarcopterygians of Australia Paleontology in New South Wales Fossil taxa described in 2013