Manus and Mussau are the northern most islands of Papua New Guinea. Their remote location means their forests, reefs, sea-grass beds and other important resources are largely unexplored.
Despite this pristine environment, both islands have experienced habitat destruction – particularly Mussau, which was heavily logged as recently as the 1990s.
Now a team of Wildlife Conservation Society (WCS) scientists has discovered that the islands are actually supporting a wealth of animals and plants including many that are thought to be new species.
The researchers will now seek to confirm their findings. Here are some of their discoveries:
Leaf-nosed bat (Hipposideros sp.)
Similar to the spurred roundleaf bat (Hipposideros calcaratus) but differing from H. calcaratus found on the Bismarck Archipelago and Manus island in its slightly larger body size, considerably wider nose leaf and much bigger ears.
Dr Richard Cuthbert, WCS Papua New Guinea director, said these variations suggest that the populations have different echolocation call frequencies, and are likely to differ in what and how they eat.
During the surveys – carried out with the permission of land owners and provincial and national authorities and funded by the Critical Ecosystem Partnership Fund – several small colonies of this species were located in caves formed in low limestone cliffs.
Flying fox (Pteropus sp.)
A member of the hypomelanus group, three specimens were collected on Emirau in 1944, but this is a very distinctive and brightly coloured individual.
The group is being revised by Kris Helgen from the National Museum of Natural History, US, and he will confirm this as a new species after comparison with the Mussau specimens.
Many small islands in Melanesia have endemic Pteropus species.
Forest dragon (Hypsilurus sp.)
This attractive dragon lizard has a very long tail that is more than three times the length of its body, and a low but distinct crest along the top of its neck.
It also has long feet and toes, which help it to climb trees to hide in their branches. The team say studies are ongoing but it appears likely that this species is new to science.
Bedstraw (Bikkia sp.)
Related to Bikkia tetrandra, a common Pacific species, but differing in the shape and size of the sepals, the flower bud, ovary and the small stature of the plants.
Its habitat on coastal limestone cliffs, exposed to constant salt spray, is also unique, as B. tetrandra, a much taller plant, occurs mostly away from the sea.
Pandanus palm (Pandanus sp.)
A miniature Pandanus species, growing no taller than 3m, with large pure white buds that turn into red succulent fruit favoured by birds and flying foxes.
It appears to be related to another species from mainland Papua New Guinea.
Tube-nosed bat (Nyctimene sp.)
This species and another on Manus – that has been previously collected – are both similar to the Umboi tube-nosed fruit bat (N. vizcaccia) of the Bismarck Archipelago.
The Manus population has previously been referred to as N. vizcaccia but the Mussau population has shorter ears and shorter-faced skulls with higher crowned teeth than those on Manus, making the researchers think it is distinct from vizcaccia.
Gecko (Gehyra sp.)
This huge gecko has a body length of at least 14cm and was found inside the mouth of a cave. The large pads on its fingers and toes allow it to climb tree trunks in the forest.
“A second individual seen on Manus island escaped by climbing more than 20m up a vertical trunk,” Dr Cuthbert said.
This new species is thought to be known only on Mussau and Manus islands.
Thrush (Zoothera sp.)
The Zoothera genus of thrushes has long been a source of taxonomic confusion, and in the New Guinea and Australian region four sub-species of the russet-tailed thrush have been recognised, including one on Mussau.
After comparison of the plumage pattern and colouration, body size and behaviour of the Mussau birds, the researchers suggest this individual should be considered a full species.
Frog (Cornufer sp.)
A ground-dwelling frog with short legs and extremely variable colour patterns on its back, suspected to be discovered for the first time.
It is a medium-sized frog, with males growing to about 4cm and females to about 7cm, that the research team found to be abundant across the island.
“The males' loud calls were a dominant feature of the soundscape around camp every evening,” Dr Cuthbert said.
Damselfly (Drepanosticta sp.)
A small, slender damselfly, which the researchers say is a new species found only in a series of streams between sea level and the summit of Mount Sabomu in the forests of southern Manus.
Vital for the whole region
“The species is extremely shy, perching for long periods in shady streamside vegetation and taking flight only when disturbed. It is almost certainly endemic to Manus island,” Dr Cuthbert said.
Despite the logging, researchers say pockets of good quality rainforest still exist on Mussau. The islanders also follow a strict Seventh Day Adventist vegetarian diet, which has helped make the island a sanctuary for many animals.
“This has resulted in large populations of coconut crabs, marine turtles and cave dwelling bats. We suspect that Mussau may be a vital source population for these species across much of Melanesia,” explains Dr Cuthbert.
“Keeping Mussau’s pristine marine environment and remaining forest is vital for the whole region.”
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