Four new species of the millipede genus Eutrichodesmus Silvestri, 1910 from Laos, including two with reduced ozopores (Diplopoda, Polydesmida, Haplodesmidae).

Weixin Liu,Sergei Golovatch,Thomas Wesener

doi:10.3897/zookeys.660.11780

Abstract

Laos has large areas of primary forest with a largely unexplored fauna. This is evidenced by millipedes, class Diplopoda, with fewer than 60 species being recorded from the country. In the widespread Southeast Asian “Star Millipede” genus Eutrichodesmus Silvestri, 1910 (family Haplodesmidae), only two of 49 recorded species have been found in Laos. Four new species of Star Millipedes are here described from caves in Laos: Eutrichodesmus steineri Liu & Wesener, sp. n., Eutrichodesmus deporatus Liu & Wesener, sp. n., Eutrichodesmus paraster Liu & Wesener, sp. n. and Eutrichodesmus parvus Liu & Wesener, sp. n.. A fifth species, for which only a female is available, remains unnamed. The defensive glands (ozopores) are found to be strongly or entirely suppressed in two of the new species, Eutrichodesmus deporatus Liu & Wesener, sp. n. and Eutrichodesmus paraster Liu & Wesener, sp. n., both troglobionts, which is new to the family. All of the Star Millipedes were collected during Northern Lao-European Cave Project faunal surveys conducted by the Senckenberg Museum, Frankfurt. A key to the six species of Eutrichodesmus currently known to occur in Laos is provided.

Highlights

The documenting of biodiversity and the subsequent taxonomic descriptions of undescribed species have been highlighted as one of the most urgent research programmes of our planet, as indicated by the declaration of the “United Nations Decade on Biodiversity”, as well as the signing of the UN “Convention on Biological Diversity” by numerous countries (e.g., Wheeler 2008; Padial et al 2010; Popescu 2015)
The very large amount of still undescribed biodiversity in Laos is especially evident in arthropods, including the large, ecologically important, mostly sylvicolous and mesophilous millipedes, class Diplopoda
Since the bulk of global millipede diversity is confined to tropical forest, which is a rapidly shrinking biome, and because diplopods are poor dispersers that are largely confined to forests and woodlands, and are prone to strongly localized endemism (e.g. Wesener 2009; Car and Harvey 2014; Enghoff 2015), the problem of documenting millipede faunas is increasingly acute (Golovatch and Kime 2009)

Summary

Introduction

The documenting of biodiversity and the subsequent taxonomic descriptions of undescribed species have been highlighted as one of the most urgent research programmes of our planet, as indicated by the declaration of the “United Nations Decade on Biodiversity”, as well as the signing of the UN “Convention on Biological Diversity” by numerous countries (e.g., Wheeler 2008; Padial et al 2010; Popescu 2015). Wesener 2009; Car and Harvey 2014; Enghoff 2015), the problem of documenting millipede faunas is increasingly acute (Golovatch and Kime 2009) These localized occurrences make millipede species important subjects for biogeographic studies (Stoev and Enghoff 2003; Wesener et al 2010; Wesener et al 2011), and put them at risk of local extinction from human activities such as forest destruction or large-scale mining operations (Wesener and Wägele 2007; Iniesta et al 2012). Laos is situated more or less north-centrally within the distribution range of the genus, but only two Laotian species have been named so far: E. multilobatus Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2009, and E. nadan Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2016 Both are highly localized endemics found in caves and are presumed troglobites (Golovatch et al 2009a, 2016a). For the first time in the family we report strongly or completely suppressed ozopores, which is unusual because all previously described Eutrichodesmus seem to show normal pore formulae: 5, 7, 9, 10, 12, 13, 15–19

Material and methods

Discussion