The terrestrial Isopoda (Crustacea, Oniscidea) of Rapa Nui (Easter Island), with descriptions of two new species

Abstract

Nine species of terrestrial isopods are reported for the Polynesian island of Rapa Nui (Easter Island) based upon museum materials and recent collections from field sampling. Most of these animals are non-native species, but two are new to science: Styloniscus manuvaka sp. n. and Hawaiioscia rapui sp. n. Of these, the former is believed to be a Polynesian endemic as it has been recorded from Rapa Iti, Austral Islands, while the latter is identified as a Rapa Nui island endemic. Both of these new species are considered ‘disturbance relicts’ and appear restricted to the cave environment on Rapa Nui. A short key to all the oniscidean species presently recorded from Rapa Nui is provided. We also offered conservation and management recommendations for the two new isopod species.

Capturing arthropod diversity in complex cave systems

“…For the six RAPA morphospecies, half were detected by both PT and visual search techniques and half using only visual search techniques. Of these, the new Polynesian endemic species, Styloniscus manuvaka , Taiti & Wynne, ; was detected using TS only, while the new island endemic, Hawaiioscia rapui Taiti & Wynne, ; was detected using both PT and OC (Taiti & Wynne, ). Both cave‐restricted PARA isopod morphospecies were detected using DIS within each cave's deep zone.…”

“…Moss gardens at both ELMA (Northup & Welbourn, ) and select Oregon caves (Benedict, ) were identified as relict habitats of the Last Glacial Maximum and may support once widespread species now restricted to this environment. On Rapa Nui, sampling fern‐moss gardens resulted in the discovery of at least eight new species (Bernard, Soto‐Adames, & Wynne, ; Mockford & Wynne, ; Taiti & Wynne, ). These animals represent endemic relict species of a severely environmentally degraded island ecosystem and thus should be considered critically important to conservation and management (Wynne et al., ).…”

“…Moss gardens at both ELMA (Northup & Welbourn, 1997) and select Oregon caves (Benedict, 1979) were identified as relict habitats of the Last Glacial Maximum and may support once widespread species now restricted to this environment. On Rapa Nui, sampling fern-moss gardens resulted in the discovery of at least eight new species (Bernard, Soto-Adames, & Wynne, 2015;Mockford & Wynne, 2013;Taiti & Wynne, 2015).…”

“…Of note, two RAPA collembolans, representing undescribed endemic species, were detected with only DIS within fern-moss gardens (Bernard et al, 2015). For Diptera Taiti & Wynne, 2015; was detected using both PT and OC (Taiti & Wynne, 2015). Both cave-restricted PARA isopod morphospecies were detected using DIS within each cave's deep zone.…”

A new species of Trichorhina Budde-Lund, 1908 (Isopoda: Oniscidea: Platyarthridae) from Paraná caves, southern Brazil

“…Until 2004, approximately 300 species of troglobiotic terrestrial isopods (Oniscidea) were known worldwide, mostly described from caves in the northern hemisphere (Taiti, 2004). Biospeleological surveys conducted in the last decades in Australia, Asia and South America have partly modifi ed this scenario and to date 331 troglobiotic Oniscidea species are known (Taiti and Gruber, 2008;Taiti and Xue, 2012;Tabacaru and Giurginca, 2013;Campos-Filho et al, 2014;Taiti 2014;Souza et al, 2015;Taiti and Wynne, 2015). Th is number is certainly not exhaustive, since a large amount of material has been recently collected and many new taxa are still waiting formal descriptions.…”