Thylacine-Thylacinus cynocephalus

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Thylacine-Thylacinus cynocephalus


A pair of thylacines in a zoo in Washington D.C., c. 1906.

Temporal range: Pliocene-Holocene (4Ma-1936 CE)

Scientific classification

Life
Domain: Eukaryota
(unranked): Unikonta
(unranked): Opisthokonta
(unranked): Holozoa
(unranked): Filozoa
Kingdom: Animalia
Phylum: Chordata
Subkingdom: Eumetazoa
(unranked): Bilateria
Superphylum: Deuterostomia
Phylum: Chordata
Infraphylum: Gnathostomata
Clade: Eugnathostomata
Clade: Teleostomi
Superclass: Tetrapoda
Clade: Reptiliomorpha
Clade: Amniota
Clade: Synapsida
Clade: Eupelycosauria
Clade: Sphenacodontia
Clade: Sphenacodontoidea
Order: Therapsida
Suborder: Cynodontia
Clade: Prozostrodontia
Clade: Mammaliaformes
Class: Mammalia
Legion: Cladotheria
Sublegion: Zatheria
Infralegion: Tribosphenida
Subclass: Theria
Clade: Metatheria
Infraclass: Marsupialia
Superorder: Australidelphia
Order: Dasyuromorphia
Family: †Thylacinidae
Genus: †Thylacinus
Species: †T. cynocephalus

Description:

The thylacine (T. cynocephalus; "dog-headed pouched one") or Tasmanian tiger or wolf was a species of predatory marsupial of the extinct family Thylacinidae that lived in Australia, Tasmania, and New Guinea. It was the largest predatory marsupial (as well as the only thylacinid) that survived into the modern era until its extinction within said period. T. cynocephalus first appeared around 4 million years ago[1], and went extinct 1936 CE.

In a way, thylacines and canids are an example of convergent evolution; this is blatantly clear to anyone who physically compares thylacines and canids at first glance, as they share the same basic superficial bauplan. Richard Dawkins notes, "They are easy to tell from a true dog because of the stripes on the back but the skeleton is harder to distinguish. Zoology students at Oxford had to identify 100 zoological specimens as part of the final exam. Word soon got around that, if ever a 'dog' skull was given, it was safe to identify it as Thylacinus on the grounds that anything as obvious as a dog skull had to be a catch. Then one year the examiners, to their credit, double bluffed and put in a real dog skull. The easiest way to tell the difference is by the two prominent holes in the palate bone, which are characteristic of marsupials generally."[2]

Another obvious and well-known feature of the thylacine was the color/pattern of its integument; the thylacine had stripes on the back and rear portion of its body (earning the name "Tasmanian tiger") while the fur was otherwise yellow-brown. Thylacines were 1-1.3 meters long in total body length with the tail being 50-65 centimeters. Furthermore, shoulder height would have been ~60 centimeters and body weights would have been in the range of 20-30 kilograms.[3] Males tended to be larger than females.[4] Life expectancy in the wild was ~5-7 years.[5]

Notwithstanding claims of thylacines having maximum jaw gapes of 120°, this is apparently an exaggeration; their maximum jaw gapes couldn't get any higher than 80°.[6] The aforementioned canids share a similar skull morphology to the thylacine (as said earlier, they are convergent). However, there were some clear differences upon closer inspection. For example, the thylacine's dental formula is 4.1.3.4/3.1.3.4; by contrast a red fox's (Vulpes vulpes) dental formula is 3.1.3.3/3.1.3.3 while that of a grey wolf's (Canis lupus) is 3.1.3.3/3.1.4.3.[7] Likewise, palatal vacuities were present in the skull of the thylacine, the nares were more flared than rectangular (as in placental carnivores), etc.[8]

T. cynocephalus possessed seven cervical, thirteen thoracic, six lumbar, two sacral, and twenty-five caudal vertebrae. The clavicles were narrow, curved, and small (~5cm), which seemingly was one adaptation to cursoriality. Its epipubic bones were yet another feature that was reduced.[9]

Diet and hunting:

Like tigers and wolves from which the animal got two of its names from, it was an apex predator. Prey included the long-nosed potoroo (Potorous tridactylus), eastern bettong (Bettongia gaimardi), eastern barred bandicoot (Perameles gunnii), short-beaked echidna (Tachyglossus aculeatus), red-necked wallaby (Macropus rufogriseus), eastern grey kangaroo (Macropus giganteus), common wombat (Vombatus ursinus), Tasmanian pademelon (Thylogale billardierii), and domesticated sheep (Ovis aries).[10] It's been suggested that smaller and more nimble prey would have served as the primary prey of the smaller and more agile females while larger quarry would have been preferable for males. This means that a) prey selection was more diverse with both genders of a single species being specialized for one type of prey and b) intraspecific competition would have been more suppressed when prey was limited.[11] According to Wroe et al. (2005), the thylacine had a rather high bite force quotient.[11][12] The bite force quotient was higher in predators that preyed on larger animals (eg. wolves, African wild dogs, and dingoes). These examples also hunt cooperatively to bring larger prey down and it's been suggested the thylacine would have been intermediate between solitary and pack hunting, being rather fox or jackal-like for small quarry and wolf-like when pack hunting.[11] A 2011 study conducted by Marie Attard et al. concluded that the jaw apparatus of the thylacine was weak to the extent that it would have been specialized in smaller prey (incidentally using this as a possible explanation of its extinction).[13][14] However, as the Thylacine Museum notes, this is in direct contradiction to contemporary accounts claiming that the thylacine indeed hunted sheep and published descriptions of a generalist diet; if Attard et al.'s findings are correct, a few facts regarding sheep must be taken into consideration. Judging from accounts written at the time, thylacines were most threatening during the lambing season; the average body mass for Merino lambs (the breed of choice for early British settlers in Tasmania) up to 90 days old is much smaller than the body mass of an adult, nearly 30 kg thylacine (though, lambs that are 90 days old are not much smaller than this), making them easy prey for even a flimsy-jawed predator. Secondly, when sheep are chased, they will eventually lie down. Dogs have been recorded taking advantage of this idiosyncrasy by easily slaughtering sheep that lie down and do nothing to retaliate; thylacines could have done the same and experienced little to no physical resistance, making any structural weakness of its feeding apparatus irrelevant.[13] Figuierido & Janis (2011) found that T. cynocephalus's elbow joint morphology was most similar to that of ambush predators such as felids than to cursorial ones such as canids[15] although its forelimbs seemed otherwise ill-suited for grappling quarry with the forelimbs. This fact, coupled with a study conducted by the very same authors of the 2011 study three years later, suggests the thylacine was, in actuality, a generalized type of predator that wasn't particularly adapted to either cursorial or ambush hunting.[16]

Extinction:

Thylacines went extinct on the Australian mainland ~3-2k years ago.[17][18] Prowse et al. (2014) found that the introduction of dingoes on Australia during this time could indeed have had some negative impact on the thylacine and Tasmanian devil populations, but the shift in climate coupled with the population growth and technological advancement of humans in Australia seems to have contributed the most to the extinction of the two indigenous marsupial predators in the mainland.[19][20] Although the majority of Australian megafaunal mammals (>90%) went extinct thousands of years earlier in the Pleistocene, the thylacine and grey kangaroo survived and wouldn't disappear from the mainland until later on.[21] Likewise, the last Australian thylacines apparently had a limited genetic diversity.[22] Letnic et al. (2012) even proposed that direct killing by dingoes in agonistic confrontations could have been a way for dingoes to contribute to thylacine extinction on the mainland. Dingoes and male thylacines were similar in size to each other, but females were significantly smaller. Because of this, plus how predators often kill smaller predators and limit their populations, it was proposed that dingoes killing smaller female thylacines could have contributed to extinction, although it was admitted that attributing the extinction to a sole factor is problematic.[23]

The thylacine was attributed to the deaths of domestic sheep in Tasmania, and so bounties were placed on it.[24][25] Hunting, competition with introduced wild dogs, habitat loss, apprehension of animals for zoos[26][27], and a distemper-like disease[28] all contributed to the rarity of the thylacine in Tasmania. On Tuesday, May 6, 1930, Wilfred Batty killed the last recorded wild thylacine (attacking his poultry) in Mawbanna.[29] On September 7, 1936, the last known thylacine (now commonly referred to as "Benjamin"[30]) died in the Beaumaris Zoo.[31] The thylacine wasn't declared extinct until half a century subsequent to "Benjamin's" death due to a 50 year criteria for the declaration of an animal's extinction (which incidentally no longer exists).[31] Sightings on both the mainland and Tasmania have occurred since "Benjamin's" death, but none are confirmed.[32] The thylacine is now a subject of cloning and de-extinction.[33]

References:

[1] web.archive.org/web/20090602070740/http://www.amonline.net.au/thylacine/08.htm
[2] Richard Dawkins (2004). The Ancestor's Tale.
[3] Sally Bryant & Jean Jackson (1999). Tasmania's Threatened Fauna Handbook pg. 190-193.
[4] "Character displacement in Australian dasyurid carnivores: size relationships and prey size patterns" (Jones, 1997).
[5] www.parks.tas.gov.au/index.aspx?base=4765
[6] www.naturalworlds.org/thylacine/biology/anatomy/external/external_anatomy_2.htm
[7] www.naturalworlds.org/thylacine/biology/anatomy/skullandskeleton/dentition/dentition_1.htm
[8] www.naturalworlds.org/thylacine/biology/anatomy/skullandskeleton/skull/skull_1.htm
[9] www.naturalworlds.org/thylacine/biology/anatomy/skullandskeleton/skeleton/skeleton_1.htm
[10]
www.naturalworlds.org/thylacine/biology/behaviour/behaviour_1.htm
[11]
www.naturalworlds.org/thylacine/biology/behaviour/behaviour_2.htm
[12] "Bite club: comparative bite force in big biting mammals and the prediction of predatory behavior in fossil taxa" (Wroe et al., 2005).
[13]
www.naturalworlds.org/thylacine/biology/behaviour/behaviour_4.htm
[14] "Skull mechanics and implications for feeding behaviour in a large marsupial carnivore guild: the thylacine, Tasmanian devil and spotted-tailed quoll" (Attard et al., 2011).
[15] "The predatory behaviour of the thylacine: Tasmanian tiger or marsupial wolf?" (Figuierido & Janis, 2011).
[16] "Forelimb anatomy and the discrimination of the predatory behavior of carnivorous mammals: The thylacine as a case study" (Figuierido & Janis, 2014).
[17] www.naturalworlds.org/thylacine/introducing/whatis/what_is_a_thylacine_1.htm
[18] Paddle (2000). pp. 23-24.
[19] www.australiangeographic.com.au/news/2013/09/dingoes-cleared-of-mainland-extinctions/
[20] "An ecological regime shift resulting from disrupted predator–prey interactions in Holocene Australia" (Prowse et al., 2014).
[21] "Timing and dynamics of Late Pleistocene mammal extinctions in southwestern Australia" (Prideaux et al., 2010).
[22] "Limited Genetic Diversity Preceded Extinction of the Tasmanian Tiger" (Menzies et al., 2012).
[23] "Could Direct Killing by Larger Dingoes Have Caused the Extinction of the Thylacine from Mainland Australia?" (Letnic et al., 2012).
[24] www.parks.tas.gov.au/index.aspx?base=4765
[25] www.naturalworlds.org/thylacine/history/persecution/persecution_1.htm
[26] "Canine Revolution: The Social and Environmental Impact of the Introduction of the Dog to Tasmania" (Boyce, 2006).
[27] www.naturalworlds.org/thylacine/history/extvssurv/extinction_vs_survival_5.htm
[28] www.naturalworlds.org/thylacine/history/extvssurv/extinction_vs_survival_2.htm
[29] www.naturalworlds.org/thylacine/history/persecution/persecution_10.htm
[30] www.naturalworlds.org/thylacine/captivity/Benjamin/Benjamin_1.htm
[31] www.naturalworlds.org/thylacine/history/extvssurv/extinction_vs_survival_1.htm
[32] www.arkive.org/thylacine/thylacinus-cynocephalus/video-00.html
[33] www.naturalworlds.org/thylacine/mrp/cloning/cloning_1.htm

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^A documentary regarding its biology and details on its extinction.

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The predatory behaviour of the thylacine: Tasmanian tiger or marsupial wolf?

Abstract

The extinct thylacine (Thylacinus cynocephalus) and the extant grey wolf (Canis lupus) are textbook examples of convergence between marsupials and placentals. Craniodental studies confirm the thylacine's carnivorous diet, but little attention has been paid to its postcranial skeleton, which would confirm or refute rare eyewitness reports of a more ambushing predatory mode than the pack-hunting pursuit mode of wolves and other large canids. Here we show that thylacines had the elbow morphology typical of an ambush predator, and propose that the ‘Tasmanian tiger’ vernacular name might be more apt than the ‘marsupial wolf’. The ‘niche overlap hypothesis’ with dingoes (Canis lupus dingo) as a main cause of thylacine extinction in mainland Australia is discussed in the light of this new information.

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Tasmanian Tiger No Match For Dingo



The wily dingo out-competed the much larger marsupial thylacine by being better built anatomically to resist the "mechanical stresses" associated with killing large prey, say Australian scientists. Despite being armed with a more powerful and efficient bite and having larger energy needs than the dingo, the thylacine was restricted to eating relatively small prey while the dingo's stronger head and neck anatomy allowed it to subdue large prey as well. Earlier studies had given ambiguous results regarding the size of prey favoured by the thylacine, and had suggested that changes in mainland Aboriginal culture may have driven its extinction 3,000 years ago in mainland Australia. This new conclusion, published today in Proceedings B of the Royal Society, is based on sophisticated computer simulations revealing bite forces and stress patterns applying to dingo and thylacine skull specimens. A team led by UNSW palaeontologist Stephen Wroe, along with Karen Moreno (UNSW) and University of Newcastle colleagues, Colin McHenry and Philip Clausen, conducted the research. The simulations illustrate mechanical stresses and strains applying to the skull, jaw, teeth and cranial muscles of both animals across a range of biting, tearing and shaking motions that simulate the impact of controlling and killing a struggling prey. Engineers use the same methodology -- known as finite element analysis -- to predict distortion and "failure" in load-bearing materials, such as metal in the body and wings of an airplane.
The researchers applied this technique to test the hypothesis that the dingo would have substantially overlapped with the thylacine regarding its choice of favourite prey. Their results demonstrated considerable similarity between the two species, but also informative differences. "The thylacine has a greater bite force than the dingo but its skull becomes more stressed than the dingo under conditions that simulate the influence of struggling prey," says Dr Wroe, who believes the bigger marsupial took downsized, relatively small prey despite its big energy requirements. "If the thylacine had been better able to hunt large prey, such as adult kangaroos and emus, as well as smaller species, then it would have faced less competition from the smaller dingo," says Dr Wroe. As well, the dingo may have enjoyed a competitive edge by having a social structure that enabled it to hunt in packs, whereas the thylacine was a lone hunter. The findings add to a complex picture of how and why the thylacine became extinct after millions of years of successful survival in Australia. Its extinction on the continent's mainland has also been linked to climate change and a shift in Aboriginal land-use patterns about the same time as the introduction of the dingo. The unique carnivore then persisted only on the island of Tasmania -- which was free of dingoes -- until the arrival of European settlers, who persecuted it believing it to be a wolf-like creature that killed sheep. Kept as pets, exported to zoos, killed by farmers and hunters, the pre-European thylacine population of around 5,000 was also pressured by government bounties: records reveal that 2,000 bounties were paid in the period the period 1888-1912. Like the dingo, the settlers competed with the thylacine's food base by hunting small animals and reducing their numbers through ecological and environmental impacts. The last known individual died in a Tasmanian zoo in 1936. "As a large dedicated flesh eater reliant on relatively small prey, the thylacine may have been particularly vulnerable, not only to food competition with the dingo -- but also to the destructive influence of the first Europeans in Australia", Dr Wroe says.

Source (hyperlink)

Be cautious of the above however.

www.naturalworlds.org/thylacine/biology/behaviour/behaviour_3.htm
www.naturalworlds.org/thylacine/biology/behaviour/behaviour_4.htm

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Some footage of "Benjamin" that I thought would be interesting.

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Reconstruction of the Cortical Maps of the Tasmanian Tiger and Comparison to the Tasmanian Devil
Gregory S. Berns, Ken W. S. Ashwell

The last known Tasmanian tiger (Thylacinus cynocephalus)–aka the thylacine–died in 1936. Because its natural behavior was never scientifically documented, we are left to infer aspects of its behavior from museum specimens and historical recollections of bushmen. Recent advances in brain imaging have made it possible to scan postmortem specimens of a wide range of animals, even more than a decade old. Any thylacine brain, however, would be more than 100 years old. Here, we show that it is possible to reconstruct white matter tracts in two thylacine brains. For functional interpretation, we compare to the white matter reconstructions of the brains of two Tasmanian devils (Sarcophilus harrisii). We reconstructed the cortical projection zones of the basal ganglia and major thalamic nuclei. The basal ganglia reconstruction showed a more modularized pattern in the cortex of the thylacine, while the devil cortex was dominated by the putamen. Similarly, the thalamic projections had a more orderly topography in the thylacine than the devil. These results are consistent with theories of brain evolution suggesting that larger brains are more modularized. Functionally, the thylacine’s brain may have had relatively more cortex devoted to planning and decision-making, which would be consistent with a predatory ecological niche versus the scavenging niche of the devil.

journals.plos.org/plosone/article?id=10.1371/journal.pone.0168993

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It looks like we've confirmed Benjamin's gender (the subject of debate) well before I even made this profile. Detailed analysis of a frame showing the underside of the endling (where the scrotum would be visible if it were male) shows that...Benjamin is a fitting name.

publications.rzsnsw.org.au/doi/pdf/10.7882/AZ.2011.047

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A photograph of a living thylacine taken in the 19th century by Frank Haes was rediscovered and published in a paper in 2016. It is now not only the oldest known photograph of a thylacine (previously it was an 1869 photo of a dead trophy specimen), but also the only known photograph of a living thylacine from the 19th century.

publications.rzsnsw.org.au/doi/pdf/10.7882/AZ.2016.022

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May 3, 2015 5:03:21 GMT 5 Infinity Blade said:

Some footage of "Benjamin" that I thought would be interesting.

Some new footage, surprisingly.

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Did the thylacine violate the costs of carnivory? Probably not: royalsocietypublishing.org/doi/10.1098/rspb.2020.1537

This study estimates the thylacine to have been typically smaller than thought. Previous average size estimates most commonly assumed 29.5 kg, but a sample of 93 adult specimens indicates an average size of 19.7 kg for males, and 13.7 kg for females. This is below the 21 kg body mass threshold for mammalian carnivores, from which they have to switch from feeding on small prey to large prey. The thylacine, therefore, was not special in this regard.

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This is just a preprint, but still interesting.

Extinction of the Thylacine

Abstract

The Thylacine (Thylacinus cynocephalus), or ‘Tasmanian tiger’, is an icon of recent extinctions, but the timing of its final demise is shrouded in controversy. Extirpated from mainland Australia in the mid-Holocene, the large island of Tasmania became the species’ final stronghold. Following European settlement, the Thylacine was heavily persecuted and pushed to the margins of its range. The last captive animal died in 1936, but numerous sightings were reported thereafter. Here we collate and characterize the type, quality, and uncertainty of over a thousand unique sighting records of Thylacines since 1910. We use this novel and unique curated database to underpin a detailed reconstruction and mapping of the species’ spatio-temporal distributional dynamics, to pinpoint refugia of late survival and estimate the bioregional patterns of extirpation. Contrary to expectations, the inferred extinction window is wide and relatively recent, spanning from the 1980s to the present day, with extinction most likely in the late 1990s or early 2000s. While improbable, these aggregate data and modelling suggest some chance of ongoing persistence in the remote wilderness of the island. Although our findings for this iconic species hold intrinsic value, our new spatio-temporal mapping of extirpation patterns is also applicable more generally, to support the conservation prioritization and search efforts for other rare taxa of uncertain status.

Significance statement Like the Dodo and Passenger Pigeon before it, the Thylacine has become an iconic symbol of human-caused extinction. Even today, reports of the Thylacine’s possible ongoing survival in remote regions of Tasmania are newsworthy and continue to capture the public’s imagination, with much debate over whether the extinction event has yet occurred and if so, when? We show, using a unique and robust spatio-temporal mapping and modelling approach, underpinned by the world’s first sightings database (from 1910-present day), that the Thylacine likely persisted until the late 20th century, with some possibility of ongoing survival.

www.biorxiv.org/content/10.1101/2021.01.18.427214v1

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Functional ecological convergence between the thylacine and small prey-focused canids

Background
Morphological convergence is a fundamental aspect of evolution, allowing for inference of the biology and ecology of extinct species by comparison with the form and function of living species as analogues. The thylacine (Thylacinus cynocephalus), the iconic recently extinct marsupial, is considered a classic example of convergent evolution with the distantly related placental wolf or dog, though almost nothing is actually known regarding its ecology. This lack of data leads to questions regarding the degree of convergence with, and the similarity of, the functional ecology of the thylacine and the wolf/dog. Here, we examined the cranium of the thylacine using 3D geometric morphometrics and two quantitative tests of convergence to more precisely determine convergent analogues, within a phylogenetically informed dataset of 56 comparative species across 12 families of marsupial and placental faunivorous mammals. Using this dataset, we investigated patterns of correlation between cranial shape and diet, phylogeny, and relative prey size across these terrestrial faunivores.

Results
We find a correlation between cranial, facial, and neurocranial shape and the ratio of prey-to-predator body mass, though neurocranial shape may not correlate with prey size within marsupials. The thylacine was found to group with predators that routinely take prey smaller than 45% of their own body mass, not with predators that take subequal-sized or larger prey. Both convergence tests find significant levels of convergence between the thylacine and the African jackals and South American ‘foxes’, with lesser support for the coyote and red fox. We find little support for convergence between the thylacine and the wolf or dog.

Conclusions
Our study finds little support for a wolf/dog-like functional ecology in the thylacine, with it instead being most similar to mid-sized canids such as African jackals and South American ‘foxes’ that mainly take prey less than half their size. This work suggests that concepts of convergence should extend beyond superficial similarity, and broader comparisons can lead to false interpretations of functional ecology. The thylacine was a predator of small to mid-sized prey, not a big-game specialist like the placental wolf.

bmcecolevol.biomedcentral.com/articles/10.1186/s12862-021-01788-8

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Melbourne Uni to resurrect Tasmanian Tiger after $5 million gift


A graphical representation of the internal structure of Tasmanian tiger joeys. Image: TIGGR Lab.

The University of Melbourne says its "one step closer" to bringing the extinct Tasmanian Tiger back to life following a $5 million philanthropic gift.

The funding will allow the university to establish a "world-class research lab for de-extinction and marsupial conservation science". Specifically, the funds will establish the Thylacine Integrated Genetic Restoration Research - or "TIGRR" - Lab.

One of the aims of the lab is to, ultimately, develop technologies that could achieve de-extinction of the thylacine - commonly known as the Tasmanian tiger - as well as "provide crucial tools for threatened species conservation".

The project will be led by Professor Andrew Pask from the university's School of BioSciences.

"While our ultimate goal is to bring back the thylacine, we will immediately apply our advances to conservation science, particularly our work with stem cells, gene editing and surrogacy, to assist with breeding programs to prevent other marsupials from suffering the same fate as the Tassie tiger," he said.

The species was once widespread across Australia but the last known Tasmanian Tiger died in captivity in 1936. According to Professor Pask, the research will investigate whether marsupial stem cells could be used make an embryo which could then be successfully transferred into a host surrogate uterus, such as a dunnart or Tasmanian devil.

The sizable donation came from the Wilson Family Trust. Mr Russell Wilson said the story of the thylacine and its unceremonious exit from this world really touched his family.

"We came across Professor Pask's incredible work, believe it or not, via some YouTube clips on him talking about his research and passion for the thylacine and Australian marsupials. We realise that we are on the verge of a great breakthrough in science through improvements in technology and its application to the genome," Mr Wilson said.

"The benefits of this open research will be wide and varied."

www.examiner.com.au/story/7641095/melbourne-university-establishes-lab-to-resurrect-tasmanian-tiger/

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Skin of apparently the last known thylacine recovered.


www.theguardian.com/australia-news/2022/dec/05/tasmanian-tiger-remains-of-the-last-known-thylacine-unearthed-in-museum?CMP=Share_iOSApp_Other

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Resolving when (and where) the Thylacine went extinct

Like the Dodo and Passenger Pigeon before it, the predatory marsupial Thylacine (Thylacinus cynocephalus), or ‘Tasmanian tiger’, has become an iconic symbol of anthropogenic extinction. The last captive animal died in 1936, but even today reports of the Thylacine's possible ongoing survival in remote regions of Tasmania are newsworthy and capture the public's imagination. Extirpated from mainland Australia in the mid-Holocene, the island of Tasmania became the species' final stronghold. Following European settlement in the 1800s, the Thylacine was relentlessly persecuted and pushed to the margins of its range, although many sightings were reported thereafter—even well beyond the 1930s. To gain a new depth of insight into the extinction of the Thylacine, we assembled an exhaustive database of 1237 observational records from Tasmania (from 1910 onwards), quantified their uncertainty, and charted the patterns these revealed. We also developed a new method to visualize the species' 20th-century spatio-temporal dynamics, to map potential post-bounty refugia and pinpoint the most-likely location of the final persisting subpopulation. A direct reading of the high-quality records (confirmed kills and captures, in combination with sightings by past Thylacine hunters and trappers, wildlife professionals and experienced bushmen) implies a most-likely extinction date within four decades following the last capture (i.e., 1940s to 1970s). However, uncertainty modelling of the entire sighting record, where each observation is assigned a probability and the whole dataset is then subject to a sensitivity analysis, suggests that extinction might have been as recent as the late 1980s to early 2000s, with a small chance of persistence in the remote south-western wilderness areas. Beyond the intrinsically fascinating problem of reconstructing the final fate of the Thylacine, the new spatio-temporal mapping of extirpation developed herein would also be useful for conservation prioritization and search efforts for other rare taxa of uncertain status.

www.sciencedirect.com/science/article/abs/pii/S0048969723014948