Three new species of cave Troglopedetes (Collembola, Paronellidae, Troglopedetinae) from Thailand, with a key to the Thai species

Katthaleeya Surakhamhaeng,Louis Deharveng,Sopark Jantarit

doi:10.3897/subtbiol.40.73143

Abstract

Thailand is today the richest country for the genus Troglopedetes Joseph, 1872, with 17 species described from the country. In this study three troglomorphic new species are described from caves in the western region. They are T. spectabilissp. nov. and T. rungsimaesp. nov. from Kanchanaburi province and T. takensissp. nov., from Tak province. The three new species share elongated antennae and have the same number of central mac on Th. III and Abd. IV. However, they differ from one another by the combination of: presence of eyes, antennal length, claw morphology, central head macrochaetotaxy and internal row of dental spines. Troglopedetes spectabilissp. nov. is remarkably different from its congeners by its extreme long appendages, especially the antennae (ratio antenna: head = 5.5). In the second part of the paper the arrangment of antennal chaetotaxy and the diversity of its phaneres is analyzed in the three new species, homologized and compared with those of two other species described from Thailand (T. meridionalis and T. kae). A total of 22 types of chaetae have now been recognized among the species. A new type of S-chaetae for the genus was discovered in this study. There are 5 types of ordinary chaetae, 15 types of S-chaetae, the subapical organite of Ant. IV and scales. A total of 1,107 to 2,183 antennal chaetae on each side were observed, which includes 308–485 S-chaetae, 687–1,402 ordinary chaetae, 72–295 scales and a subapical organite.

Highlights

The genus Troglopedetes Joseph, 1872 is widespread in Thailand in both edaphic and subterranean environments, in the western and northern regions of the country (Deharveng 1987; Jantarit et al 2020)
Two species were recently described from southern Thailand (T. meridionalis Jantarit, Surakhamhaeng & Deharveng, 2020 and T. kae Jantarit, Surakhamhaeng & Deharveng, 2020), and these were the first records of the genus from the south of the Kra Isthmus, a major zoogeographical boundary in this region (Jantarit et al 2020)
It is similar to T. dispersus Deharveng & Gers, 1993, in the absence of eyes, and the dorsal macrochaetotaxy of the central head. It differs from it by its longer antennae, outer maxillary lobe chaetotaxy (1 vs 2), chaetae on lateral flap of the ventral tube (8+8 versus 7+7), and higher ratio of dens: mucro (9.1 vs 8.5). We found another morphotype with a different claw morphology

Summary

Introduction

The genus Troglopedetes Joseph, 1872 is widespread in Thailand in both edaphic and subterranean environments, in the western and northern regions of the country (Deharveng 1987; Jantarit et al 2020). Ventral chaetotaxy of head densely covered with oval scales (57–67 μm long), postlabial chaetae along the linea ventralis as ciliated mes anteriorly and 3 ciliated chaetae laterally, one mac and an oblique line of 5–6 mes posteriorly on each side (Fig. 8G). Distal row with 7–9 subequal ciliated mes and a dorso-apical tenent hair thin, pointed on all tita; a ventro-distal strong smooth erected chaeta present on Tita III (Fig. 10A).

Results

Conclusion