A new jewel-like species of the pill-millipede genus Verhoeff, 1924 (Diplopoda, Sphaerotheriida, Zephroniidae) from Thailand.

A new species of the giant pill millipede genus is described: from the northeastern part of Thailand. Species delimitation is based on morphological characters and COI sequence data. The new species can be clearly discriminated from congeners by its greenish-blue body color, the face mask-like appearance of the thoracic and anal shields jointly when rolled up, and the combination of the following four characters: (1) the coxa of the second leg laterally with a sharp and long process, (2) the tarsi of legs 4-21 with 6-7 ventral spines, (3) the anterior telopods consisting of four conspicuous telopoditomeres, and (4) the immovable, slender (not strongly humped) and distally curved finger of the posterior telopods without a membranous spot.

Two new millipede species of the genus Pimvichai, Enghoff, Panha & Backeljau, 2020 (Diplopoda, Spirobolida, Pseudospirobolellidae).

Two new millipede species of the genus Pimvichai, Enghoff, Panha & Backeljau, 2020 from Thailand are described: from Loei Province and from Uttaradit Province. The descriptions are based on gonopod morphology and two mitochondrial gene fragments (COI and 16S rRNA). The phylogenetic mtDNA analysis assigned the two new species unequivocally to the consistently well-supported clade, in which they form a fifth subclade that was well supported by maximum likelihood analysis of 16S rRNA, though neither by Bayesian inference nor by COI.

Redescription of the giant Southeast Asian millipede Pocock, 1893 and its assignment to the new genus gen. nov. (Diplopoda, Spirobolida, Pachybolidae).

A new genus of the millipede family Pachybolidae from Southeast Asia is described: , with Pocock, 1893 as type species. This latter species is DNA barcoded (COI) and redescribed based on male morphological characters, which hitherto were unknown. The new genus differs from other pachybolid genera by having (1) the preanal ring process long and protruding beyond the anal valves and (2) the anterior gonopod telopodite distally abruptly narrowed, forming an extremely long, slender, elevated process curved caudad.

Molecular phylogeny of the Thyropygus allevatus group of giant millipedes and some closely related groups.

Giant cylindrical millipedes of the family Harpagophoridae, especially species of the genus Thyropygus, are broadly distributed in Thailand and nearby countries. They show a great deal of variation in body size, color patterns and gonopodal characters. Phylogenetic analyses of 26 nominate species from six genera in the subfamilies Harpagophorinae and Rhynchoproctinae, as well as nine new morphotypes (regarded as new species), were performed with the DNA sequences from two mitochondrial gene fragments (16S rRNA and COI).