Rob Gess with portions of Hyneria udlezinye in the rocks that were saved from roadworks.Credit: Rob Gess
A giant species of prehistoric lobe-finned fish, new to science, has been described in a study published in PLOS ONE.
The lobe-finned fish, about three-metres long, referred to as ‘one who eats others’, is a giant killer with fanged jaws whose presence in prehistoric Southern Africa dates back 360 million years.
“Hyneria udlezinye is the biggest prehistoric bony fish ever described from southern Africa,” says palaeontologist Rob Gess, of the Albany Museum in Makhanda, South Africa.
“Udlezinye, meaning ‘one who eats others’ is a Xhosa word, the indigenous language widely spoken in the Eastern Cape.” Its description was pieced together from individual bones from a number of individual fish fossils found over the course of more than three decades. These come from shale rock excavated from a road cutting at a farm, outside the town of Makhanda in South Africa's Eastern Cape province.
Gess, an expert on animals and plants spanning the Devonian period, 420 to 359 million years ago, described the new species with lobe-finned fish expert, Per Ahlberg from Uppsala University, Sweden.
The discovery of a closely related species of Hyneria, this time from Gondwana, strengthens the belief that all giant Tristichopterids originated in the supercontinent of Gondwana, only later migrating to the northern supercontinent of Euramerica.
“Hyneria udlezinye represents an important missing piece of the puzzle,” said Gess. It is the first Tristichopterid to be discovered in such a high paleoaltitude, within the ancient southern polar region. All other species so far found were in zones located around the equator in prehistoric times.
Hyneria udlezinye (centre) reconstructed within the Waterloo Farm ecosystem. From a painting by Maggie Newman based on research by Rob Gess.Credit: Maggie Newman
"We now believe that giant Tristichopterids were probably found around the world. Our previous impression was influenced by the lack of Late Devonian fossil sites from outside the tropics," explained Gess. "In fact, the rocks containing fossils at Waterloo Farm provide our only comprehensive record of an entire ecosystem from within polar regions during the Late Devonian era."
The first fossils at Waterloo Farm were discovered when road works started around Makhanda in the mid 1980s. At the time, Gess was at high school in the town. He has since spent most of his career as a palaeontologist working with fossils from the site. When further roadworks put the ancient fossil records in jeopardy, the South African roads agency assisted Gess in moving 30 tonnes of rock in 1999, and a further 70 tonnes in 2008, to his backyard in Bathurst, 40 kilometers away,
Since then, Gess has patiently chipped through 25% of the rock and has discovered remains of approximately 60 kinds of plants and animals . Only two of these were known to science.
Hyneria udlezinye is the 26th species to be formally described and named. Among those fossils of 11 fish species, including strange-looking armour-plated ones, spiny finned sharks, sharks, lungfish and an extinct coelacanth species. Gess also uncovered the fossilized remains of the oldest bloodsucking, jawless lamprey fish yet known, bone impressions of stem tetrapods, the earliest four-legged animals found in what today is Africa, and the tail and pincer of an ancient scorpion. The latter is the oldest remains of a land-living animal yet discovered from the supercontinent of Gondwana.
“These finds are all mixed in with many kinds of plants, waterweeds and seaweeds,” notes Gess.
Pieces of a puzzle There was no big reveal in the discovery of Hyneria udlezinye, Gess said
“There wasn't a wondrous moment where I opened a rock and there it all was. It is the result of a 37-year quest and the collecting of clues over decades, academic study, international collaboration and intricate and rigorous scientific detective work.”
It started with the discovery of some fossilized fish scales in 1985, then bits of skull and shoulder girdle in the 1990s, followed by major pieces in 1999 and a steady trickle thereafter.
“The most recently collected clue, a partial set of lower jaw bones turned up last year whilst my PhD student, Ryan Nel, was helping me to split rocks.”
Scientific reconstruction of the head and shoulder girdle of Hyneria udlezinye, as illustrated in the paper by Gess and Ahlberg.Credit: Rob Gess
Reconstructing the head and shoulder girdle became a meticulous scientific jigsaw puzzle when Gess and Ahlberg had to match pieces from different sized individuals based on their shape, the alignment of sensory canals (with which fish detect movement in water) and the overlap area on the bones, that show how and where they locked into adjacent bones.
“We don’t have one complete fish but have managed to accurately reconstruct almost the entire head and shoulder girdle of this fish species. We do have remains of other parts of the body, but these were also disarticulated by the time that they were fossilized. For the back portion of the reconstruction, we relied on closely related fish of the same age from Australia,” Gess explained.
Curiously the teeth of the fish were less well preserved than the bones; they tend to be black rather than silvery in colour against the dark shale rock.
Gess says Hyneria udlezinye is not the biggest species of fish found in shale rock from Waterloo farm, though it is the biggest bony fish.
“Being an estuarine lagoon the site was influenced by both the river that ran into it, and the sea into which it opened, at least for part of the year. Hyneria udlezinye would have come from the river.”
