The soggy boots of the team slide backwards in the black mud as they struggle up towards the ridge line separating the forest edge from one of the last unexplored places on Earth.

The rain is an incessant barrage of watery bullets firing down through the tree canopy. Thunder crashes. Tangles of vines and spider webs make for a Hollywood movie scene of truly impenetrable jungle.

Near the front of the seven hikers is a Welshman carrying a billhook, a backpack almost the same size as him, and what appears to all intents and purposes to be a briefcase. The slope is so steep that the heavy briefcase clatters against the ground at every step, so he swings it in front of him – clonk – like a ship using an anchor to warp out of harbour against the green, vertical tide. He takes two steps up and swings the case up the hill again. Clonk.

On this wet March day in Mozambique, Professor Julian Bayliss, naturalist, explorer, fellow of the Royal Geographical and Royal Entomological societies, is heading deep into the green heart of the Mabu forest for the first time. The forest, also known as the “Google forest” after the way he “discovered” it using Google Earth in 2005, has more recently been called “the butterfly forest”, after the butterflies that congregate around the summit of Mount Mabu at certain times of year. Many of the species since identified here carry Bayliss’s name. These include Nadzikambia baylissi, the sleek little chameleon with the prehensile tail, and Cymothoe baylissi, the graceful forest gliding butterfly, both of which exist only here within the largest rainforest in southern Africa.

“One other thing we have discovered on this trip,” shouts Bayliss, with a huge grin over the sound of yet another downpour on another day on another seemingly unending hillside ascent, “Mabu is not flat.”

The scientific discovery of Mount Mabu was a huge breakthrough. Working with Kew Royal Botanic Gardens, the Mozambique government’s institute for agricultural research (IIAM) and the Darwin Initiative, Bayliss was sitting at his laptop looking at Google Earth in 2005, when he wondered whether mountains in Mozambique might also harbour some of the species he was uncovering in nearby Malawi. So he and a Malawian botanist named Hassam Patel decided to take a look.

As reported by the Observer, over the years Bayliss and the Kew Gardens team have since identified three new species of snake, eight species of butterfly, a bat, a crab, two chameleons and many plants, as well as a trove of rare birds that are critically endangered.

However, no one has ever journeyed into the heart of the forest until now. Previous discoveries came from the forest base camp, the peak and a small satellite camp, all on the lower eastern edge. To explore Mabu’s secrets further, an expedition has been undertaken this month by the international scientific and environmental reporting initiative Alliance Earth.

The Alliance Earth team’s objectives were to create a 3D map, uncover new species, check on the health of the forest, publish an ethno-botanical study, seek out potential non-timber forest products, produce a feature documentary and film a 360-degree virtual reality experience for museums and science centres around the world, so everyone can explore the mountain’s mysteries.

Alliance Earth’s 360-degree look at the ‘Google forest’. Copyright: Jeffrey Barbee/Alliance Earth

“This is a new species of Dipsadoboa,” Bayliss says, holding the poisonous tree snake with a twinge of obvious concern. As it writhes, he holds it farther away from his torso. “This is currently undescribed, it doesn’t have a name yet.” Stretching out imploringly, the snake tries to reach the perceived safety of my video camera. “To find an actual new species of snake is extremely exciting, and very rare.” He has now found three new snakes in Mabu’s forest.

According to Bayliss, on this trip the team have identified at least one new butterfly species, and quite possibly more, once genetic testing confirms them. They have also found a Caecilian, one of the rarest animals on Earth, which is sort of a cross between a reptile and amphibian, and may be a new type of its kind.

But these precious finds aren’t the only new discoveries that have him excited. Under a huge tree he airs his wet boots, squeezing his socks dry before putting them on again. “Yesterday was great. We discovered a new waterfall, which is fantastic. We’ve never been here before, and because it’s the rainy season the water was just crashing through the rocks.”

More discoveries have come daily, such as the “valley of giants”, an open canyon with a central raised ridge surrounded by the largest grouping of big trees yet found. Their vast trunks stretch upwards like a cathedral, blending into the green nave of leaves hundreds of metres above. These waterfalls, huge trees, deep canyons, and riverside camping spots are important geographical discoveries that Bayliss hopes will help bring tourists here.

At times the forest guides are clearly as perplexed about directions as the team, looping round in ever-widening circles in search of a way across the maze of folded valleys, often climbing up and down one punishing ridge after another in order to make headway.

Bayliss holds what is possibly yet another previously unidentified species of butterfly. Photograph: Jeffrey Barbee

Senior hunter turned guide Ofélio Cavalião, 41, and his son Bartolomeo, 26, joined the expedition one morning before breakfast, hiking from their home many kilometres away. They heard through the grapevine that Bayliss had returned and so tracked him down. Cavalião and Bayliss have worked together on every visit he has made to Mabu’s forest. The local hunter and famous scientist have developed a friendship and deep respect for one another.

Once Cavalião arrived, the team started to push deeper into the most unexplored parts of the eastern forest, following the tops of the ridges and making better time.

Guides such as Cavalião have an intimate knowledge of the area, making the outside “discovery” of Mabu a purely scientific designation. According to him, the local people have benefited from the forest for generations. It even saved their lives during the back-to-back conflicts that started in 1964 with the war of independence against Portugal, before segueing into the civil war that finally ended in 1992.

His friend, 38-year-old guide Ernesto André, agrees. He grew up in the forest, sheltered from the ravages of war, with dozens of other people in small forest camps. Not far into the undergrowth, holes the size of unfilled graves are clearly man-made. Standing in one, André explains that these sheltered whole families and were the only way to hide the sounds of crying children from the Portuguese soldiers who tried to hunt them down.

On a remote ridge line with another potential new butterfly in his net, Bayliss talks about the future of the mountain. “Every new discovery helps make the case for the mountain to be officially protected,” he says.

But time is of the essence. The team finds the forest intact, yet still not officially protected. A recent report in the Guardian told how, despite a two-year ban on timber exports, corruption and organised crime are still stripping Mozambique of forests such as this. According to the independent Environmental Investigation Agency, as much as $130m worth of hardwoods are stolen from Mozambique annually. Much of it is sent to China.

Ecologically aware visitors could help build a tourism industry here that protects the forest and benefits the community in a sustainable way, while safeguarding the incredible biodiversity, according to Justiça Ambiental, the Mozambican environmental justice group that has been working at Mabu since 2009 to create and implement an eco-tourism plan for the mountain.

Mount Mabu expedition 2017. Produced by Alliance Earth. Edited and written by Jeffrey Barbee. Camera Jeffrey Barbee and Julian Bayliss. Copyright: Jeffrey Barbee/Alliance Earth

The group’s forestry specialist, Rene Machoco, explains that its vision is for Mabu to be legally designated as a community conservation area.

André says that before Justiça Ambiental came, his community didn’t think the forest was particularly valuable, “but then it was explained and we knew the truth. The forest is life and the forest is wealth”.

Tourism is only one way to help people like Ernesto benefit from their home. Expedition team member Ana Alecia Lyman is a non-timber forest products specialist based in Mozambique who runs Bio Óleos de Miombo. “Non-timber forest products, such as honey or mushrooms, can be sustainably derived from the landscape to generate income in rural communities without jeopardising local biodiversity,” she says.

After seeing the forest first-hand, she is enthusiastic and feels that the more people who are engaged in these sustainable value chains, the more local investment there can be in the health of the forest.

Under the tree canopy, Bayliss is hunting an elusive butterfly that finally flutters and rests on the leafy forest floor in a scattered beam of sunlight. Butterflies use solar energy to fly. Their wing veins are usually dark in order to channel energy from the sun to engage their muscles. This is why when they are seen slowly folding their wings while perched in the sunlight, they are getting ready to take to the air. But the shy brown butterfly with the spotted wing markings is no match for the speedy scientist from Wales. A deft swing loops the net shut, “I think I got it!”

“This is probably a new species,” he says, looking through the net and walking over to a sunny spot. Extracting it gently he examines the wing spots. “This is probably the one we have been looking for.” He looks closer. With a breathless voice he breaks with his usual understatement. “This is very exciting – this is the first time I have ever seen this butterfly.”

What else awaits discovery in the remote forest of Mabu’s basin? Potential answers to that question sit snugly in Bayliss’s anchor-like briefcase: motion-sensitive video cameras, the first ever to be deployed at Mabu. Encased in steel boxes and strapped to trees, the four high-definition cameras will be left running at secret locations deep in the foliage for two years.

Having finished securing the last camera above a stream, Bayliss washes his hands in the clear water among the mossy rocks, looking satisfied. “Every time we come to Mabu we discover something new. Who knows what we will find next?”

The question hangs in the air as he turns around and starts back on the long hike to base camp with his butterfly net in hand, his briefcase empty, and his wet boots squishing merrily.

Alliance Earth paid for Jeffrey Barbee’s transport and accommodation.