BIODIVERSITY/ENTOMOLOGY - Name of new harvestman species pays tribute to Lord of the Rings character

Iandumoema smeagol is the third species of its genus to be described and 
the first without eyes (photo: Maria Elina Bichuette)

PETER MOON

A group of Brazilian researchers have gained unusual international media attention for their work in naming a new species of harvestman after one of the most important characters in J.R.R. Tolkien’s novels The Hobbit and The Lord of the Rings trilogy.

A scientific article describing the recently discovered obscure arachnid was published in the journal ZooKeys on November 18, and the story was immediately reported by several widely read newspapers and magazines, including the Washington Post, USA Today, Time, National Geographic, and New Scientist, among others.

Approximately a thousand species of harvestman are known to live in Brazil, and over 6,000 species are found worldwide. A dozen live in underground environments. Iandumoema smeagol is the third species of the genus to be described and the first without eyes. The others are also Brazilian and troglobitic (exclusively cave dwelling): I. uai Pinto-da-Rocha 1996 and I. setimapocu Hara & Pinto-da-Rocha 2008, both of which occur in Minas Gerais.

Sméagol is the name of a hobbit in Tolkien's novels who becomes a pale, slimy cave-dweller who is renamed Gollum after falling under the influence of a powerful ring. He uses the ring to commit crimes and is banished by his people. He finally takes refuge in a deep cave. Far from the light and the outside world, he dwells underground for over 400 years. The ring’s malign spell twists his body and mind. He develops huge eyes to see in the dark, unlike I. smeagol, which is blind.

“I love Tolkien. I devoured his books before I saw the movies. I’ve always wanted to name an animal for one of his characters,” saidMaria Elina Bichuette, a professor affiliated with the Underground Research Laboratory at the Federal University of São Carlos (UFSCar).

It was her team that discovered I. smeagol at the bottom of a cave called Toca do Geraldo in northern Minas Gerais. “It’s highly modified and specialized,” she said. “When we decided to describe it, I asked Ricardo what he thought of naming it for Sméagol, and he agreed on the spot.”

Ricardo Pinto-da-Rocha is a professor at the University of São Paulo’s Bioscience Institute (IB-USP) and a specialist in harvestmen, having described over 120 species.

“Opiliones, popularly called daddy longlegs or harvestmen, are arthropods of the arachnid class,” he said. “They’re relatives of spiders, but they aren’t spiders. This is important because people often think they are,” said Pinto-da-Rocha, who in the recently published article acknowledges funding received from FAPESP as part of a Thematic Project under the aegis of FAPESP’s BIOTA Program and the US National Science Foundation’s Dimensions of Biodiversity Program, which are collaborating on research in Brazil’s Atlantic rainforest.

“Among other things, the spider’s abdomen is separate from the rest of its body, whereas the harvestman’s is fused,” he said.

Toca do Geraldo

Some of the key features of the newly described species are that it is eyeless and nearly without pigmentation. Additionally, the second of its four pairs of legs are very long, measuring 2.5 centimeters, whereas the body is only 0.5-cm-long.

“It doesn’t use the second pair for locomotion. They’re sensory appendices, like antennae, with which it explores the environment and feels its way around. The hairs can sense the movement of air in the cave. These legs are very important to it,” said Pinto-da-Rocha.

The story behind the discovery of I. smeagol began in 2013, when Bichuette, who has been studying caves for some 20 years, began supervising Masters student Rafael da Fonseca-Ferreira, the other author of the article published in ZooKeys.

They were prospecting cave fauna in the Monjolos area near Serra do Espinhaço, which has a dry season and a rainy season with transitional vegetation between the cerrado and caatinga biomes.

“One day, we saw a man working in a field and asked him if he knew of any nearby caves,” Bichuette said. “His name was Geraldo. He told us about a cave to which he referred as a toca, which means ‘hole’ or ‘lair’, so we called it Toca do Geraldo in his honor. We were the first speleologists to explore it. It was unknown to science until then.”

The entrance to the cave is a long narrow crevice approximately 12-m-long and only 80-cm-wide. After wriggling through this fissure, the speleologists had to crawl down a long tunnel, which eventually opened out into a vast hall more than 100-m in length and 50-m in height, cluttered with fallen rocks and carpeted with leaves swept into the cave by surface runoff during the rainy season.

The decomposing leaves serve as food for the animals that live in the cave. A certain amount of light filters through from the outside world. They crossed the hall and continued along another tunnel until they came to an underground river deep in the dark interior. That was where they found the blind harvestman I. smeagol.

“The fauna is richly diverse. We identified several spiders, snails, mites, and springtails, as well as vertebrates, such as toads and colonies of bats, whose guano or droppings are an important source of food in the cave,” Bichuette said.

Harvestmen are solitary and omnivorous. “We counted 14 individuals all told. They all lived in isolation from each other. I saw one feeding on the remains of a dead animal,” she recalled.

I. smeagol’s habitat is very humid, consisting mostly of cave walls and the clay deposited on the banks of the underground river. “We don’t yet know how or when the species ended up in the cave and evolved to become eyeless,” Bichuette said.

The closest relatives in the same genus are harvestmen, which live aboveground in humid forest areas, inhabiting tree bark, hollow trunks, bromeliads, and the layer of leaves on the forest floor. They are nocturnal animals.

No other species of harvestman was found in the vicinity of Toca do Geraldo. “It’s a very dry area. No harvestmen are known to live outside the cave,” Pinto-da-Rocha said.

A plausible explanation for this absence could be that the ancestors of I. smeagol inhabited the area in the distant past when it was more humid. As the climate became drier, the harvestmen that lived above ground disappeared, leaving the population of cave dwellers isolated. “They probably evolved a long time ago, when the area was humid,” he suggested.

A small number of harvestmen of the same species were found in Lapa do Santo Antônio, a cave located 4.6 km away from Toca do Geraldo. “This suggests there may be a connection between the two caves,” Bichuette said. “So far, we’ve explored about 1.5 km of Toca do Geraldo and noticed that the underground river continues farther, indicating a larger habitat for the species.”

Fieldwork to study the habits and populations of I. smeagol is ongoing. “We’re monitoring these two caves and mapping other caves in the area. These animals are very fragile and rare. They need to be studied, and their habitat must be protected. Otherwise, extinction is a real threat for the species,” she said.

The team is now preparing descriptions of other new species that live in the “lost” ecosystem of Toca do Geraldo.

The article published in ZooKeys, “A new highly specialized cave harvestman from Brazil and the first blind species of the genus:Iandumoema smeagol sp. n. (Arachnida, Opiliones, Gonyleptidae)” (doi: 10.3897/zookeys.537.6073), by Ricardo Pinto-da-Rocha, Rafael Fonseca-Ferreira and Maria Elina Bichuette, can be read at http://zookeys.pensoft.net/articles.php?id=6073.

Originally published at Agência Fapesp