Shop Forum More Submit  Join Login
About Traditional Art / Professional Brian ChooMale/Australia Group :iconprehistory-alive: Prehistory-Alive
Bringing prehistory back to life
Recent Activity
Deviant for 6 Years
Needs Core Membership
Statistics 76 Deviations 665 Comments 85,038 Pageviews
×

Newest Deviations

Dromornis planei (the former Bullockornis) by Gogosardina Dromornis planei (the former Bullockornis) :icongogosardina:Gogosardina 120 27 Ligulalepis toombsi by Gogosardina Ligulalepis toombsi :icongogosardina:Gogosardina 180 7 Hongyu chowi by Gogosardina Hongyu chowi :icongogosardina:Gogosardina 186 8 Sparalepis tingi by Gogosardina Sparalepis tingi :icongogosardina:Gogosardina 175 11 The Leviathan of Beaumaris by Gogosardina The Leviathan of Beaumaris :icongogosardina:Gogosardina 292 43 Moythomasia lineata by Gogosardina Moythomasia lineata :icongogosardina:Gogosardina 147 11 Yi qi. Dragon of the Daohugou by Gogosardina Yi qi. Dragon of the Daohugou :icongogosardina:Gogosardina 313 67 Microbrachius dicki = Sex in the Devonian by Gogosardina Microbrachius dicki = Sex in the Devonian :icongogosardina:Gogosardina 134 30 Megamastax - the first vertebrate apex predator by Gogosardina Megamastax - the first vertebrate apex predator :icongogosardina:Gogosardina 316 31 TSoSC#4 = Lariosaurus goes for a stroll by Gogosardina TSoSC#4 = Lariosaurus goes for a stroll :icongogosardina:Gogosardina 311 37 Chengjiang Biota - the dawn of the vertebrates by Gogosardina Chengjiang Biota - the dawn of the vertebrates :icongogosardina:Gogosardina 209 22 Elephant bird = The Kiwi's lost cousin by Gogosardina Elephant bird = The Kiwi's lost cousin :icongogosardina:Gogosardina 149 24 Entelognathus #4: Study of a weird fish by Gogosardina Entelognathus #4: Study of a weird fish :icongogosardina:Gogosardina 101 6 Entelognathus #3: Shaking the tree by Gogosardina Entelognathus #3: Shaking the tree :icongogosardina:Gogosardina 60 8 Entelognathus #2: Evo from the fish's mouth by Gogosardina Entelognathus #2: Evo from the fish's mouth :icongogosardina:Gogosardina 59 8 Entelognathus #1: In the Silurian seas of Yunnan by Gogosardina Entelognathus #1: In the Silurian seas of Yunnan :icongogosardina:Gogosardina 205 37

Activity


Dromornis planei (the former Bullockornis)

acrylics, digital & photography, 2015 &2018

ca.13 million years ago, mid-Miocene, Bullock Creek, Northern Territory, Australia

At the onset of the breeding season, two Dromornis planei drakes warily size each other up. The closer bird utters a booming warning call while the other male examines his rival’s brightly coloured bill, a reliable indicator of health and strength.

Dromornis planei is the bird formerly known as Bullockornis the Demon Duck of Doom. As it turns out, these magnificent 2.5m tall birds were neither ducks nor the bringers of doom.

Mihirungs (Dromornithidae) were once considered to be giant flightless members of the waterfowl clade Anseriformes. Recent analyses have revealed that they belong to an extinct radiation of stem-Galloanserae, basal to both waterfowl and the Galliformes.

A popular 1990s hypothesis presented these birds as hypercarnivores, which used their enormous beaks to slice up their prey. Subsequent research has failed to support this model and these animals were probably herbivores or generalist omnivores. Arguments against the “duck of doom" model include = 

* Absence of a hooked bill or sharp talons for tearing meat.
* The bill, while deep, is also extremely thin with limited attachment areas for biting musculature.
Small eyes that face to the sides of the head.
High relative abundance to potential prey. Large mihirungs are often the most abundant big animals in their fossil assemblage.

Multiple phylogenetic analyses have resolved Bullockornis as being deeply nested within Dromornis as the sister-taxon of D.stirtoni. The mid-Miocene D.planei (= Bullockornis) is so similar to the late Miocene D. stirtoni that the two are likely an example of anagensis within a single population over time. “Bullockornis” differs from D. stirtoni in having stockier, shorter legs while the bones in the back of the skull are a bit less squished together. Together, this pair clusters with later D. australis, the type species from the early Pliocene, and the Oligocene-Miocene D. murrayi, the oldest member of the genus.

So what did Dromornis use its gigantic bill for? Recent research by Warren Handley and Trevor Worthy at Flinders Uni has shown the uppermost parts of the upper bills of many specimens are both roughened and highly porous, pitted with numerous blood vessels. It is possible that this surface acted as an anchor for a soft-tissue structure, so with Worthy's guidance I've reconstructed a greatly enlarged cere covering most of the upper mandible, similar to that of the modern Cape Barren Goose (Cereopsis). So perhaps the remarkable bills of Dromornis evolved to maximise a brightly coloured display surface.

   

 

 

 

 

Loading...
Ligulalepis toombsi
2017. acrylics, pencil, digital and photography.

ca.400 million years ago, Early Devonian (Emsian), Burrunjuck area, New South Wales, Australia (Taemas Limestone)

Illustration for = Alice M Clement, Benedict King, Sam Giles, Brian Choo, Per E Ahlberg, Gavin C Young, John A Long (2018) Neurocranial anatomy of an enigmatic Early Devonian fish sheds light on early osteichthyan evolution. eLIFE DOI: 10.7554/eLife.34349

A pair of sardine-sized fishes (Ligualepis cf.toombsi) cruise over a shallow coastal reef off the shores of far-eastern Gondwana.

Ligulalepis
lived from the latter part of the Silurian to the Early Devonian Period. It was originally described on the basis of isolated scales, initially from the Early Devonian (Emsian) of New South Wales (L. toombsi) and subsequently in the Silurian (Ludlow) of Yunnan, China (L. yunnanensis). The scales were rhombic in shape and similar to those found in Devonian ray-finned fishes. Unsurprisingly, it was long considered to be an early-model actinopterygian.

In 2000, a partial braincase and skull roof from the Taemas Limestone of NSW (where the original type scales were found) was tentatively assigned to this genus and displayed a very odd combination of characters. So odd that Ligulalepis has bounced around the cladograms as a stem-gnathostome (basal jawed fish), a stem-osteicthyan (basal bony fish), a stem-actinopterygian (primitive ray-finned fish), or even a stem-sarcopterygian (primitive lobe-finned fish).

In 2016, PhD student Ben King made a phenomenal discovery at Taemas = a second skull (ANU V3628) in much better condition than the original. A bunch of us from Flinders University, Uppsala University and Oxford examined both these skulls with the benefit of micro-CT scanning and have provided a detailed description of this ancient fish. Ligualepis is resolved as a stem-osteichthyan, representing a form that branched off before the divergence of the ray-finned and lobe-finned fishes. It is the most basal bony fish known from a decent 3-dimensionally preserved braincase.

While Ligualalepis was a bony fish, it's skull contained a suite of characters more typical of other vertebrate groups. For example, it had =
*an eyestalk, an archaic character present in placoderms and chrondrichthyans but long thought to be absent in bony fishes.  
*a median hypophysial vein linking the pituitary vein to the hypophyseal chamber, a configuration also found in early placoderms.
*a labyrinth region (in the otic capsule) similar to early sharks and acanthodians, but entirely different from those of other bony fishes.

With our greater understanding of this and other ancient fishes, we are closing in on the default settings for all the jawed vertebrates.

Note that these reconstructions are largely hypothetical. At present all we have of this fish are disarticulated skulls, scales, fin-rays and possibly a lower jaw. It is probable, but not 100% certain, that the excellent skulls go with the type scales. No other fish fossils from the Taemas Limestone (placoderms, acanthodians and sarcopterygians) possesses the distinctive linear ornament found on the scales and skulls attributed to Ligualepis.
Loading...
Hongyu chowi
2014+2017, acrylics on card, digital & photography

c.370,000,000, Late Devonian (Famennian), Ningxia, China (Zhongning Formation)

Illustration for Min Zhu, Per E. Ahlberg, Wen-Jin Zhao, and Lian-Tao Jia (2017) A Devonian tetrapod-like fish reveals substantial parallelism in stem tetrapod evolution. Nature Ecology & Evolutiondoi:10.1038/s41559-017-0293-5

A Late Devonian riverbed on the North China microcontinent, Hongyu erupts from the sand to snack on some passing Ningxialepis. The spiny armor of these small antiarchs is of little use against snapping jaws of this voracious ambush predator.

ANIMALS IN SCENE
Hongyu chowi = Tetrapodomorph sarcopterygian, 1.5 m long. A large and very unusual lobe-finned fish known from a single well preserved specimen comprising a partial skull (unfortunately missing most of the snout), pectoral girdle and vertebrae.

The anatomy throws a spanner into tetrapodomorph phylogeny as it presents of mosaic of supposedly basal and derived characters. For example, the robust shoulder girdle, broad flattened head and the contact between the supratemporal and extratemporal bones are characteristic of rhizodonts, forms that are considered close to the base of the tetrapodomorph radiation.

On the other hand, Hongyu has a truncated hyomandibular, big plate-like scapulacoracoids and a cleithrum that lacks a ventral lamina. These are characters seen in early tetrapods and tetrapod-like elpistostegalians such as Tiktaalik. Another odd feature, not mentioned in the paper, is the absence of a bony gill cover in the holotype. The the bones may have originally been present and become lost before preservation, but this seems odd given that the delicate gill arches are still in articulation. If Hongyu truly lacked a bony operculum (as I have reconstructed here), then this is yet another tetrapod-like character.

Not surprisingly, this new fish doesn't neatly fit anywhere in the established phylogenetic models. My gut feeling is that this is an unusual basal tetrapodomorph that has independently acquired tetrapod-like characters due to anatomical specialisation as a benthic ambush predator. Then again, perhaps this discovery means that rhizodonts are closer to the origin of tetrapods than we have previously recognised. 

Ningxialepis spinosa = small antiarch placoderm, 20 cm long. Jiangxilepid antiarch with serrated edges to the pectoral fins and a tall median dorsal spine.

Remigolepis major = large antiarch placoderm, 1.2 m long. Of the half-dozen or so species of Remigolepis present in the Zhongning Formation, R. major was the largest, exceeding 1 metre in length.
Loading...
We made this holoscape with pics we downloaded off Google images - spared no expense.

scontent-b-sjc.xx.fbcdn.net/hp…

deviantID

Gogosardina's Profile Picture
Gogosardina
Brian Choo
Artist | Professional | Traditional Art
Australia
An Australian vertebrate palaeontologist. I mainly work on Silurian-Devonian fishes, especially basal actinopterygians.
Interests

Comments


Add a Comment:
 
:iconashleyxbrooke:
AshleyxBrooke Featured By Owner May 30, 2018  Hobbyist Photographer
Hey there! :la:

Nice art :wow:  If you're ever looking to share your work with other people, live, you should check out #ThumbHub on dAmn (Did you know we had a chat system!? A lot of people don't :( ) We get a lot of great artists popping in to share their work and it varies from Traditional art, to photography, to poetry :) Also a great place to gain more exposure for your art AND to make some new friends xx


Hope to see you there some time :heart:

:gummybear:
Reply
:icongwfb5:
gwfb5 Featured By Owner Nov 21, 2017
Happy Birthday!
Reply
:iconwilly276:
Willy276 Featured By Owner Nov 21, 2017
Happy Birthday!
Reply
:iconevodolka:
Evodolka Featured By Owner Nov 21, 2017  Hobbyist General Artist
happy birthay
Reply
:iconbraindroppings1:
Braindroppings1 Featured By Owner Nov 21, 2017  Hobbyist Traditional Artist
Happy birthday!
Reply
Add a Comment: