Our smallest frog find

IT was the ultimate discovery in the Land of the Unexpected – in some of the highest mountains in Papua New Guinea a scientific expedition has found one of the smallest creatures in the world.
The world was notified of the discovery two weeks ago and the rest is history although the enormity of the discovery has not quite sunk into the minds PNG authorities and the ordinary Papua New Guinean.
Field work by researcher Fred Kraus, pictured above left, from Bishop Museum, Honolulu, Hawaii, aided by the National Museum and Art Gallery in Port Moresby, has found the world’s smallest frogs in the mountains of Milne Bay province.
This also makes them the world’s smallest tetrapods (non-fish vertebrates).
The frogs belong to the genus Paedophryne, all of whose species are extremely small, with adults of the two new species – named Paedophryne dekot and Paedophryne verrucosa – only 8mm to 9mm in length.
The study was published two weeks ago in the open access journal ZooKeys.
Kraus told The National by email last week that the expedition on which these two frog species (both at equally diminutive size) were discovered worked in the saddle area between Mt Dayman and Mt Suckling, Milne Bay province, in March and April. (see map)
“Our two camps were located at 950m and 1,850m elevation,” he said, adding that they had hoped to work two additional camps at higher elevations, where they would expect to find more undiscovered frog species, but logistical difficulties prevented them from doing so. 
“Realistically, we need to get dropped off near the top of Mt Suckling in a helicopter to work those areas and then walk out, but we had no luck finding any to rent at a price I could afford because the helicopter companies were all working the LNG project or other mine sites at pretty full capacity.” 
But Kraus would like to get back there, if possible. And Bulisa Iova from the National Museum and Art Gallery in Port Moresby agrees, saying that this was what the landowners said following the successful expedition.
Both acknowledged the local hospitality, especially landowner leader Elliot Gagomin “who so generously allowed us to work on his land and who organised the logistics for this expedition.”
Given the importance of the latest finds, Iova says he, as the government representative on the trip, had given a detailed report to the National Museum management with anticipation of a similar detailed report from Kraus and the Bishop Museum.
Going by Iova’s account, the expedition started in Port Moresby where he and Kraus flew to Milne Bay administrative capital Alotau to organise logistics and supplies. Then it was a two-hour dinghy ride north to Rabaraba district where they met the main party of guides and porters assembled by Gagomin as well as villagers who wanted to be part of history.
The westward trek inland, to the proposed site at Biniguna, at the foot of Mt Suckling took two days through unmarked village tracks and over raging streams. The first camp was home to the weary travellers as they plotted their assault on the summit.
Iova says they moved uphill the following week, camped overnight and then progressed to the second site at 1,800m which served as base for Kraus and his team for the next two weeks.
Kraus said his previous research had led to the discovery of Paedophryne in 2002 from nearby areas, but the genus was not formally described until last year (Kraus 2010, also in Zookeys).
The two species described earlier were larger, attaining sizes of 10mm-11mm, but the genus still represents the most miniaturised group of tetrapods in the world.
“Miniaturisation occurs in many frog genera around the world,” said the author, “but New Guinea seems particularly well represented, with species in seven genera exhibiting the phenomenon,” he wrote in Zookeys.
“Although most frog genera have only a few diminutive representatives mixed among larger relatives, Paedophryne is unique in that all species are minute.” The four known species all inhabit small ranges in the mountains of southeastern New Guinea or adjacent, offshore islands. Their closest relatives remain unclear.
“The members of this genus have reduced digit sizes that would not allow them to climb well; all inhabit leaf litter, and their reduced digits may be a corollary of a reduced body size required for inhabiting leaf litter and moss.
“Habitation in leaf litter and moss is common in miniaturised frogs and may reflect their exploitation of novel food sources in that habitat. The frogs’ small body sizes have also reduced the egg complements that females carry to only two, although it is not yet known whether both eggs are laid simultaneously or at staged intervals.”
How long these frogs remain the world’s smallest and safe in their natural habitat depends on the state, through the department of environment and conservation, ensuring that flora and fauna in the area stay protected from exploitation by logging and mineral exploration interests.
The National reported last week that an overseas mining company has been granted licence to explore for nickel just north of Mt Suckling in the Cape Nelson area of Milne Bay while in the Rabaraba district at least two companies have licences to explore for gold.
Iova was made of aware of these developments on Wednesday. “If these people continue and intensify their explorations into these pristine forests these new discoveries will be destroyed,” he lamented.