Museum: Seeking cave crabs of Bali

As a museum curator, I've done field work in lots of places, but this was the first time I'd had to wear a purple sash.

The sash and sarong were hired for 5,000 rupiah (about 50c) from a shop by the main road on the island of Nusa Penida, near Bali, Indonesia. I was about to venture into a cave to look for endangered crabs, but because the cave is also a popular Hindu temple you have to be properly attired.

The Giri Putri temple used to be just a smallish hole on a hillside; you have to crouch, clamber, and shuffle to enter it, before the ceiling rises and you're in one of several large caves. Today, there are steps, buildings, white-clad priests praying, and a visitor's book.

Back in 1993 Australian biologist Tony Whitten explored Giri Putri, and was struck by the number of crabs scuttling about on the cave floor. He collected some, and they turned out to be not one, but two new species, dubbed Karstarma emdi and K. balicum.

Freshwater crabs like these can be found in several cave systems in south-east Asia. They have long legs for feeling their way about in total darkness. Isolation and time leads to speciation, and the two species in Giri Putri seem to be found nowhere else but this small cave.

Unfortunately, they're under threat. Giri Putri is now a busy temple with artificial lighting everywhere, large fans to keep the air moving, lots of concrete and tiled floor and rows of benches and altars.

Whitten noted that in every visit he made there were fewer crabs, and in the hour I spent searching with a headlamp in the dark corners of the cave I didn't see any at all. I asked one priest if the crabs were there. He told me "sometimes".

The International Union for Conservation of Nature is pushing for better monitoring of the crab population, and the temple authorities seem keen to work to minimise human impact, so here's hoping.

There's plenty of other life in Giri Putri, though. I kept disturbing bats which zipped here in there in silence, sometimes an inch from my face, reminding me that I didn't get a rabies vaccination before coming to Bali. The walls of the cave were crawling with invertebrates, including large Periplaneta cockroaches, camel crickets that looked just like the cave wētā back in New Zealand and good-sized whipscorpions.

Back home, I uploaded the photos I'd taken with my phone to NatureWatch, and asked Mark Harvey at the Western Australian Museum what he thought. Mark identified them as tailless whipscorpions in the family Phrynidae, probably the genus Phrynus.

This was interesting, because almost all species of Phrynus are found in the New World, through Mexico and Central America. The sole exception is a species Mark himself named and described, Phrynus exsul from the island of Flores, Indonesia, thousands of kilometres away from its closest relatives.

Only one problem: Bali is 400 km away from Flores. So either these whipscorpions are Phrynus exsul and a new record far west of where they were first observed, or they're an undescribed species of Phrynus.

Whipscorpions are not especially inconspicuous. Giri Putri is right by the main road, and a popular tourist destination. Nusa Penida is a short ferry ride from Bali, which has millions of tourists a year. And it seems that in over 20 years nobody has thought to collect one of these critters, take it to an expert, and find out if it's an undescribed species or not.

This is the plight of the tropics in miniature: stuffed full of biodiversity which is disappearing faster than we can discover and put names to it.

*Mike Dickison is curator of natural history at the Whanganui Regional Museum. This is his 50th and final Chronicle column, as he leaves Whanganui soon to become New Zealand Wikipedian at Large.