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- Aug 13, 2015
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Hi! This is my first post on these forums. I've been reading FT since the early 1990s and it's long been my favourite magazine, so I was honoured to recently get a short article published in FT, about the Queensland marsupial tiger/yarri. I was limited for space, so had to considerably cut down the article for publication - it's a work in progress, possibly part of a larger book one day. It's certainly hard to do justice towards summarising the topic in such a small space, especially because it branches out beyond Queensland with connections to ABCs, thylacines, thylacoleos, giant quolls and the like.
Largely, my article was required to fall back on summarising and discussing the various animals - known and unknown - that may account for sightings in the yarri complex, which has already been done to varying extents by other authors. I had intended to end up focusing more on my own injection to the mix, namely possible extant quadrupedal carnivorous kangaroos, but had to cut this back by editorial request. For the sake of interest, below is the relevant section before being pruned for publication -
"That last point hardly lends credibility to my new suggestion that the cryptids encountered in some sightings might represent a living descendant of the powerful-toothed giant rat kangaroo or ‘Riversleigh killer kangaroo’, Ekaltadeta ima. This carnivorous or omnivorous animal is known only from a few Miocene fossils from northern Queensland, and would have been around the size of a large wallaby. Unlike a wallaby, however, it appears to have been a quadruped, running on all fours with relatively long, strong forearms, shorter back legs and a broad, sturdy head. Photos of the lower jaw bones have drawn obvious attention to the dangerous-looking javelin-tipped, tusk-like lower front teeth, which look like the stabbing weapons of a dedicated killer to most people. However, teeth of this relative size or smaller are not uncommon in vegetarian or omnivorous diprotodontid marsupials and are generally obscured by the lips and cheeks of the animal. In the case of modern kangaroos, they are smaller, have a blunter chisel tip and are used to nip off grass shoots and other vegetation. The teeth that have convinced many palaeontologists of E. ima’s largely carnivorous diet are instead found further back - the large serrated carnassial premolars [13, 14, 15]. There is (to the non-specialist eye) some very broad similarity here to the dental layout of the marsupial lion, which has distinctly elongated, bolt cutter-like premolars, with pincer-like paired incisors at the front. Indeed, the point that first drew me to consider an Ekaltadeta-like animal for inclusion in the yarri mystery was the realisation that from some distance, such an animal could look similar to a marsupial lion, albeit smaller and perhaps unlikely to be tackling any prey larger than a possum or rock wallaby.
E. ima was not the only large toothsome, quadrupedal kangaroo to have existed in prehistory – it’s just received most of the press. Balbaroo fangaroo and Nambaroo gillespieae (both known from the Riversleigh site) had large curved canine teeth in their upper jaws, which may have looked fearsome but were probably for display or sparring purposes according to palaeontologists [12]. The related group of giant rat kangaroos (propleopine kangaroos), of which E. ima is the oldest known species, branched out from the late Miocene to the Pleistocene, giving rise to E. jamiemulvaneyi (late Miocene), Jackmahoneya toxoniensis (Pliocene), Propleopus oscillans, P. chillagoensis and P. wellingtonensis (all Pleistocene). E. jamiemulvaneyi was nearly one and a half times the size of E. ima. P. oscillans, the best known Propleopus species, was probably the least carnivorous propleopine but was also one of the largest, around the size of a grey kangaroo. Mostly found in more southerly parts of the country, fossil remains have also been found in s.e. Queensland. Conversely, the similar-sized Queensland species P. chillagoensis is thought to have been the most specialised carnivore of the lot, though still omnivorous to some extent. Less is known of P. wellingtonensis, from New South Wales [16, 17]. Could an unknown descendant of these giant rat kangaroos have survived to modern times in the wilds of Queensland?
If these animals or their unknown descendants had bands of dark stripes (which are observed on a number of other small, living marsupials) and a bushy tail, they could easily fit some sightings. Some reports do mention kangaroo-like hind legs, but this is an observation that has sometimes been made of thylacines as well, despite its falsity (the resemblance is rather due to the tail and the manner in which it joins the hindquarters). I will be the first to admit that my giant rat kangaroo hypothesis is a very unlikely one, due to the great age of the only known remains, and lack of any known large intermediary descendants from post-Pleistocene times. Yet for the sake of considering all possible candidates we must include even remote possibilities, as with the thylacoleonids, until proven otherwise.
Although most other ancient kangaroos are believed to have been predominantly herbivores, they may not have been unthreatening to humans, if ancient myth is to be believed. A story recorded from people indigenous to the Lachlan River area (New South Wales) relates how their ancestors once had to contend with marauding groups of giant kangaroos, which sometimes chased down people and “without mercy crushed their victims with their powerful arms”. These kangaroos were eventually overcome by the shamanically-inspired use of fire to drive them over cliffs [18]. If such events really did occur in the distant past, the animal responsible could well have been the giant short-faced kangaroo, Procoptodon goliah, which stood more than 2.5m tall, and had large arms and clawed paws which were probably more than capable of crushing and tearing an adult human to death. Although not mentioned in the story, the feet and their large clawed toes would also have been lethal; modern kangaroos spar with each other, and defend themselves at close range, by grappling with their paws, balancing on the tail and kicking out with both feet, which can easily disembowel or at least seriously wound. Nevertheless, there is no indication in this story of kangaroos biting or eating the people they had killed, and the teeth of P. goliah are not those of a carnivore. Regardless, even modern kangaroos and wallabies will sometimes eat meat given the chance (ie. if meat is left out for the taking); they are not known to kill large animals for that purpose, but might occasionally eat a small lizard, for example. Perhaps these proud giants saw the similarly tall, bipedal humans as resource-competitors, invaders of territory, and a threat to be dispatched? They certainly had the size to do something about it."
Largely, my article was required to fall back on summarising and discussing the various animals - known and unknown - that may account for sightings in the yarri complex, which has already been done to varying extents by other authors. I had intended to end up focusing more on my own injection to the mix, namely possible extant quadrupedal carnivorous kangaroos, but had to cut this back by editorial request. For the sake of interest, below is the relevant section before being pruned for publication -
"That last point hardly lends credibility to my new suggestion that the cryptids encountered in some sightings might represent a living descendant of the powerful-toothed giant rat kangaroo or ‘Riversleigh killer kangaroo’, Ekaltadeta ima. This carnivorous or omnivorous animal is known only from a few Miocene fossils from northern Queensland, and would have been around the size of a large wallaby. Unlike a wallaby, however, it appears to have been a quadruped, running on all fours with relatively long, strong forearms, shorter back legs and a broad, sturdy head. Photos of the lower jaw bones have drawn obvious attention to the dangerous-looking javelin-tipped, tusk-like lower front teeth, which look like the stabbing weapons of a dedicated killer to most people. However, teeth of this relative size or smaller are not uncommon in vegetarian or omnivorous diprotodontid marsupials and are generally obscured by the lips and cheeks of the animal. In the case of modern kangaroos, they are smaller, have a blunter chisel tip and are used to nip off grass shoots and other vegetation. The teeth that have convinced many palaeontologists of E. ima’s largely carnivorous diet are instead found further back - the large serrated carnassial premolars [13, 14, 15]. There is (to the non-specialist eye) some very broad similarity here to the dental layout of the marsupial lion, which has distinctly elongated, bolt cutter-like premolars, with pincer-like paired incisors at the front. Indeed, the point that first drew me to consider an Ekaltadeta-like animal for inclusion in the yarri mystery was the realisation that from some distance, such an animal could look similar to a marsupial lion, albeit smaller and perhaps unlikely to be tackling any prey larger than a possum or rock wallaby.
E. ima was not the only large toothsome, quadrupedal kangaroo to have existed in prehistory – it’s just received most of the press. Balbaroo fangaroo and Nambaroo gillespieae (both known from the Riversleigh site) had large curved canine teeth in their upper jaws, which may have looked fearsome but were probably for display or sparring purposes according to palaeontologists [12]. The related group of giant rat kangaroos (propleopine kangaroos), of which E. ima is the oldest known species, branched out from the late Miocene to the Pleistocene, giving rise to E. jamiemulvaneyi (late Miocene), Jackmahoneya toxoniensis (Pliocene), Propleopus oscillans, P. chillagoensis and P. wellingtonensis (all Pleistocene). E. jamiemulvaneyi was nearly one and a half times the size of E. ima. P. oscillans, the best known Propleopus species, was probably the least carnivorous propleopine but was also one of the largest, around the size of a grey kangaroo. Mostly found in more southerly parts of the country, fossil remains have also been found in s.e. Queensland. Conversely, the similar-sized Queensland species P. chillagoensis is thought to have been the most specialised carnivore of the lot, though still omnivorous to some extent. Less is known of P. wellingtonensis, from New South Wales [16, 17]. Could an unknown descendant of these giant rat kangaroos have survived to modern times in the wilds of Queensland?
If these animals or their unknown descendants had bands of dark stripes (which are observed on a number of other small, living marsupials) and a bushy tail, they could easily fit some sightings. Some reports do mention kangaroo-like hind legs, but this is an observation that has sometimes been made of thylacines as well, despite its falsity (the resemblance is rather due to the tail and the manner in which it joins the hindquarters). I will be the first to admit that my giant rat kangaroo hypothesis is a very unlikely one, due to the great age of the only known remains, and lack of any known large intermediary descendants from post-Pleistocene times. Yet for the sake of considering all possible candidates we must include even remote possibilities, as with the thylacoleonids, until proven otherwise.
Although most other ancient kangaroos are believed to have been predominantly herbivores, they may not have been unthreatening to humans, if ancient myth is to be believed. A story recorded from people indigenous to the Lachlan River area (New South Wales) relates how their ancestors once had to contend with marauding groups of giant kangaroos, which sometimes chased down people and “without mercy crushed their victims with their powerful arms”. These kangaroos were eventually overcome by the shamanically-inspired use of fire to drive them over cliffs [18]. If such events really did occur in the distant past, the animal responsible could well have been the giant short-faced kangaroo, Procoptodon goliah, which stood more than 2.5m tall, and had large arms and clawed paws which were probably more than capable of crushing and tearing an adult human to death. Although not mentioned in the story, the feet and their large clawed toes would also have been lethal; modern kangaroos spar with each other, and defend themselves at close range, by grappling with their paws, balancing on the tail and kicking out with both feet, which can easily disembowel or at least seriously wound. Nevertheless, there is no indication in this story of kangaroos biting or eating the people they had killed, and the teeth of P. goliah are not those of a carnivore. Regardless, even modern kangaroos and wallabies will sometimes eat meat given the chance (ie. if meat is left out for the taking); they are not known to kill large animals for that purpose, but might occasionally eat a small lizard, for example. Perhaps these proud giants saw the similarly tall, bipedal humans as resource-competitors, invaders of territory, and a threat to be dispatched? They certainly had the size to do something about it."
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