The rediscovery of a “missing” New Guinea bat, and the value of collecting and documenting modern biodiversity.
Scientific museum specimens were often collected for one reason, and then used in studies that were not even imagined by the original field collector. This is easy to understand for collections made 100 years ago for taxonomic purposes and that are now used for studies of stable isotopes, ancient DNA, environmental toxicology, and evidence of global climate change. And these are just a few of the many modern high tech uses of museum specimens.
But recent work on bats in New Guinea has turned this around. Collections made for modern studies of logging impact have uncovered an important specimen valuable for basic taxonomy – and for recognizing a species that has not been definitively documented in over 120 years.
In a report just published in the Australian Museum Scientific Publications, a group of researchers from Australia’s University of Queensland were mist-netting in Central Province Papua New Guinea, as part of a larger study to investigate the impacts of logging and to compile a reference library of ultrasonic bat recordings. They had only a couple mist nets and harp traps set up in the forest, and they captured 42 specimens of 10 species, and the vast majority of captures were of a single species, the Common Blossom Bat. But there was one specimen that was unusual and the team could not identify it in the field.
The unknown specimen was collected and it took many months of research and the specimen being loaned to the Australian museum before it could be positively identified, based on a number of obscure characteristics. It turned out to be Thomas’s big eared bat, Pharotis imogene, previously known definitively from only one locality – Kamali village in Central Province, Papua New Guinea. This species is the only representative of its genus, Pharotis, and has the largest ears of any of the New Guinea big-eared bats.
Thomas' big-eared bat from near Oio Village, Photo Catherine Hughes
Because it had not been documented or collected in over 100 years, many people presumed it was extinct. But many regions of the world are biologically very poorly known and poorly documented. According to The Bats of Papua New Guinea by Frank Bonaccorso, “the species probably still exists, yet remains difficult to survey by routine collecting methods. Surveying with harp traps near potential roost trees or caves in the Kamali and Tuman River areas of Central Province may prove effective in the study of this species.” In fact, this study that used a single harp trap extended the known range by over 120 km to the east.
The harp trap used to collect the Pharotis specimen, set along a logging track in the Abau District, Central Province, Papua New Guinea
Bats are notoriously difficult to identify even by experts, especially in a place like Papua New Guinea where there is so much diversity. Although Pharotis is known from a small series of specimens (mostly collected in 1890), all are old and there is no preserved tissue available or barcode data available for comparison. Even the authors of the report found it quite difficult to figure out what they had, and they would never had been able to (or even persisted in trying) without the specimen in hand. This new modern specimen could be extremely valuable in documenting this species, developing new diagnostic tools such as DNA barcoding, and for creating better morphological keys.
Image of Thomas' big-eared bats from the field guide, The Bats of Papua New Guinea by Frank Bonaccorso
Sadly, most of the previously collected specimens of Pharotis have been lost. Luckily some early specimens were distributed to the American Museum, the Australian Museum and the British Museum of Natural History, but others were lost due to a flooded Italian museum and to poor collections management elsewhere.
This study highlights the value of museum specimens in modern research, and the importance of taking specimens in modern field studies. Ironically, these studies were undertaken to assess the impacts of selective logging. The biggest threat to lowland forest in PNG is due to habitat loss from logging, mining, and oil palm conversion. One of the few things that might slow habitat loss is the fact that one little poorly known female bat was recently collected there.