Over a million spiral horned antelopes – the Scimitar-horned oryx once galloped across vast areas of Northern Africa.

It was one of several other species of antelope which lived in the Sahara desert and nearby Sahelian grassland areas.

By the 1990s the oxyx had disappeared. It was extensively hunted, while at the same time its habitat dwindled.

Though they are fully protected, the same fate is looking likely for its close cousin, the Saharan Addax antelope.

In March 2016 conservationists performed extensive surveys to assess the status of this species. An aerial team covered over 3,300 km while a ground team scoured over 700 km of known Addax habitats. In 18 hours of flying none were spotted.

It was only after the ground team followed 10km of antelope track that they caught trail of one small group.

In a devastating discovery, they came across three lonely and nervous looking individuals. They may be the last remaining ones in the wild.

"We are witnessing in real time the extinction of this iconic and once plentiful species," says Jean-Christophe Vié, of the IUCN Global Species Programme

"Without immediate intervention, the Addax will lose its battle for survival in the face of illegal, uncontrolled poaching and the loss of its habitat."

In 2010 the species was already listed at critically endangered in the wild, but surveys suggested there were still 200 remaining.

However, Addax habitats have since been affected by intense political upheaval, namely the Libyan conflict of 2011, where armed militia entered into known Addax areas. Niger's oil industry has also caused a significant disturbance.

Other animals in the region are also under threat for similar reasons, including cheetahs, Dama gazelles and the Slender horned gazelle.

Vié and colleagues now recommend a set of "emergency measures to help save the Addax from imminent extinction".

These include keeping this one last population safe by using armed soldiers to prevent poaching.

Increased protection of those that live in the Termit and Tin-Toumma National Nature Reserve in eastern Niger is also being proposed, as it is home to about 300.

Another lifeline may be to reintroduce captive Addax species. Fortunately many healthy captive Abbex antelope remain.

But it will be a difficult task to prevent this species from being lost forever, as David Mallon of the IUCN antelope specialist group explains:

"We are gravely conserved about this unfolding wildlife disaster in the desert. This species is simply unable to cope with the current levels of disturbance and illegal killing. Without urgent coordinated action at all levels we will very soon witness its demise.