Liz and Gary Doyle's 8mm "mainland thylacine" film, Wilpena Pound (1973)

Few pieces of film carry as much weight in the hunt for the mainland thylacine. The Tasmanian tiger is the animal at the centre of it all, and this short clip from South Australia is the most widely shared film offered as evidence that thylacines survived on the mainland.

It is also one of the least examined. No museum. No wildlife agency. No university. The copies that circulate online are badly degraded. No published statement in the Doyles' own words has surfaced.

1973. Wilpena Pound, in the Flinders Ranges of northern South Australia. No day or month has ever been published.

Liz and Gary Doyle, a young married couple, were in their caravan. One account places them at the entrance to the Pound. An animal ran across the road in front of them. Liz filmed it through the caravan window.

About ten seconds of 8mm film. One description speaks of "an unknown quadruped" that "ran from right to left some distance in front of them." Film Threat called it "the silhouette image of an unidentified canine-type animal running across a road," with an outline that "clearly suggests it is not a fox or a feral dog."

The animal is yellow-brown and dog-shaped. It runs at speed. Some viewers see stripes on the rump, which one forum comment traced "from right behind the withers/shoulders to mid tail." In a few frames it might have large ears, though that may be the distortion of the copy. Others note a "kangaroo-like posture" in several frames. According to Where Light Meets Dark, this corner of the Flinders Ranges is also the setting of an Adnyamathanha Dreamtime story about the thylacine, a claim no other source has yet confirmed.

The main study came from Chris Rehberg of Where Light Meets Dark. His first analysis appeared in 2006, when nobody knew where the original film was. Rehberg set frames beside David Fleay's 1933 Hobart Zoo footage of a male thylacine. He pointed to four features: the proportion of the hind foot to the other bones of the leg, the proportion and posture of the tail, the shape of the hindquarters, and the depth of the neck and chest.

In 2017 Rehberg reached Liz Doyle. She confirmed she still has the original 8mm film. He followed with a backstory page and an analysis of enhanced footage. The Recently Extinct Species database calls his work "preliminary."

The debate is about identity, not honesty. No one has accused the Doyles of faking the film.

The leading ordinary explanation is a fox that has lost much of the fur on its tail, possibly to mange. The stripes may be pixelation from compression, not the animal's coat. Film Threat put it simply: "The blurry nature of the film makes it difficult to positively identify the animal as a thylacine." Even the posture cuts both ways, because "there is no known footage of a running thylacine."

Copies spread across YouTube, posted, Film Threat noted, "obviously without the permission of the couple." A fan produced a stabilised version. The T.R.U. Podcast devoted an episode to it. When a clip from the Adelaide Hills surfaced in 2016, the press reached back to the Doyle footage for background.

It should not be confused with the film Rev. Harold Doyle shot at Beaumaris Zoo in Hobart in 1930. Same surname. A different film, a different era.

The original still sits with Liz Doyle. It is said to be clearer than anything online. No new scan has been published.