Materpiscis
Encyclopedia
Materpiscis is a genus
of ptyctodontid placoderm
(a class of extinct, superficially shark-like armored fishes) from the Late Devonian (about 380 million years ago) located at the Gogo Formation
of Western Australia
. Known from only one specimen, it is unique in having an unborn embryo
present inside Materpiscis, and with remarkable preservation of a mineralised placental feeding structure (umbilical cord
). This makes Materpiscis the oldest known vertebrate
to show viviparity
, or giving birth to live young.
by Lindsay Hatcher during the 2005 expedition to the Gogo led by John Long
of Museum Victoria
. Fossils from the Gogo Formation are preserved in limestone
nodules, so dilute acetic acid
is used to dissolve the surrounding limestone and reveal the fossil
.
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Examination of the tail section of the Materpiscis specimen led to the discovery of the partially ossified skeleton of a juvenile Materpiscis and the mineralised umbilical cord. The team published their findings in 2008.
Materpiscis would have been about 11 inches (28 cm) long and had powerful crushing tooth plates to grind up its prey, possibly hard shelled invertebrates like clams or corals.
The ptyctodontid fishes are the only group of placoderms to display sexual dimorphism
, where male
s have clasping organs and female
s have smooth pelvic fin bases. It had long been suspected that they reproduced using internal fertilisation, but finding fossilised embryos inside both Materpiscis and in a similar form also from Gogo, Austroptyctodus, proved the deduction was true.
Materpiscis attenboroughi was selected as one of "The Top 10 New Species" described in 2008 by The International Institute for Species Exploration at Arizona State University
and an international committee of taxonomists.
who first drew attention to the significance of the Gogo fish sites in his 1979 series Life on Earth.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of ptyctodontid placoderm
Placodermi
Placodermi is a class of armoured prehistoric fish, known from fossils, which lived from the late Silurian to the end of the Devonian Period. Their head and thorax were covered by articulated armoured plates and the rest of the body was scaled or naked, depending on the species. Placoderms were...
(a class of extinct, superficially shark-like armored fishes) from the Late Devonian (about 380 million years ago) located at the Gogo Formation
Gogo Formation
The Gogo Formation in the Kimberley region of Western Australia is a Lagerstätte that exhibits exceptional preservation of a Devonian reef community.- Sedimentology :...
of Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
. Known from only one specimen, it is unique in having an unborn embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
present inside Materpiscis, and with remarkable preservation of a mineralised placental feeding structure (umbilical cord
Umbilical cord
In placental mammals, the umbilical cord is the connecting cord from the developing embryo or fetus to the placenta...
). This makes Materpiscis the oldest known vertebrate
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...
to show viviparity
Vivipary
Vivipary has two different meanings. In animals, it means development of the embryo inside the body of the mother, eventually leading to live birth, as opposed to laying eggs...
, or giving birth to live young.
Discovery
The fossil specimen was found in the Kimberley area of northern Western AustraliaWestern Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
by Lindsay Hatcher during the 2005 expedition to the Gogo led by John Long
John A. Long (paleontologist)
John Albert Long is an Australian paleontologist who is currently the Vice President of Research and Collections at the Natural History Museum of Los Angeles County. He is also an author of popular science books. His main area of research is on the fossil fish of the Late Devonian Gogo Formation...
of Museum Victoria
Museum Victoria
Museum Victoria is an organisation which operates three major state-owned museums in Melbourne, Victoria, Australia; these are: the Melbourne Museum, the Immigration Museum and Scienceworks. It also manages the Royal Exhibition Building and a storage facility in Melbourne's City of Moreland.Museum...
. Fossils from the Gogo Formation are preserved in limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
nodules, so dilute acetic acid
Acetic acid
Acetic acid is an organic compound with the chemical formula CH3CO2H . It is a colourless liquid that when undiluted is also called glacial acetic acid. Acetic acid is the main component of vinegar , and has a distinctive sour taste and pungent smell...
is used to dissolve the surrounding limestone and reveal the fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
.
Anatomy and physiology
Materpiscis would have been about 11 inches (28 cm) long and had powerful crushing tooth plates to grind up its prey, possibly hard shelled invertebrates like clams or corals.
The ptyctodontid fishes are the only group of placoderms to display sexual dimorphism
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
, where male
Male
Male refers to the biological sex of an organism, or part of an organism, which produces small mobile gametes, called spermatozoa. Each spermatozoon can fuse with a larger female gamete or ovum, in the process of fertilization...
s have clasping organs and female
Female
Female is the sex of an organism, or a part of an organism, which produces non-mobile ova .- Defining characteristics :The ova are defined as the larger gametes in a heterogamous reproduction system, while the smaller, usually motile gamete, the spermatozoon, is produced by the male...
s have smooth pelvic fin bases. It had long been suspected that they reproduced using internal fertilisation, but finding fossilised embryos inside both Materpiscis and in a similar form also from Gogo, Austroptyctodus, proved the deduction was true.
Materpiscis attenboroughi was selected as one of "The Top 10 New Species" described in 2008 by The International Institute for Species Exploration at Arizona State University
Arizona State University
Arizona State University is a public research university located in the Phoenix Metropolitan Area of the State of Arizona...
and an international committee of taxonomists.
Etymology
The species was named Materpiscis attenboroughi in honour of David AttenboroughDavid Attenborough
Sir David Frederick Attenborough OM, CH, CVO, CBE, FRS, FZS, FSA is a British broadcaster and naturalist. His career as the face and voice of natural history programmes has endured for more than 50 years...
who first drew attention to the significance of the Gogo fish sites in his 1979 series Life on Earth.
In popular culture
- Materpiscis was featured in the second episode of Animal ArmageddonAnimal ArmageddonAnimal Armageddon is an American paleontology-based documentary television miniseries that originally aired from to on Animal Planet. All the prehistoric scenes are created 100% in Lightwave...
.
See also
Other important fossil fishes from the Devonian period:- GogonasusGogonasusGogonasus was a lobe-finned fish known from 3-dimensionally preserved 380 million-year-old fossils found from the Gogo Formation in Western Australia. It lived in the late Devonian period, on what was once a 1400 kilometre coral reef off the Kimberley coast surrounding the north-west of Australia...
, also discovered at the Gogo Formation - TiktaalikTiktaalikTiktaalik is a genus of extinct sarcopterygian from the late Devonian period, with many features akin to those of tetrapods . It is an example from several lines of ancient sarcopterygian "fish" developing adaptations to the oxygen-poor shallow-water habitats of its time, which led to the...
- EusthenopteronEusthenopteronEusthenopteron is a genus of prehistoric lobe-finned fish which has attained an iconic status from its close relationships to tetrapods. Early depictions of this animal show it emerging onto land, however paleontologists now widely agree that it was a strictly aquatic animal...
- PanderichthysPanderichthysPanderichthys is a 90–130 cm long fish from the Devonian period 397 million years ago, of Latvia. It is named after the german-baltic palaeontologist Christian Heinrich Pander. It has a large tetrapod-like head...
- OnychodusOnychodusOnychodus is a genus of prehistoric lobe-finned fish which lived during the Devonian period . It is one of the best known of the group of onychodontiform fishes. Scattered fossil bones of Onychodus were first discovered in 1857, in North America, and described by John Strong Newberry...