Tuesday, August 31, 2021

[Diplopoda • 2021] Sphaerobelum aesculus & Zephronia viridisoma • Integrative Description of New Giant Pill-Millipedes (Diplopoda, Sphaerotheriida, Zephroniidae) from southern Thailand


 Sphaerobelum aesculus Zephronia viridisoma
Rosenmejer & Wesener

in Rosenmejer, Enghoff, Moritz & Wesener, 2021.

ABSTRACT
Two new species of giant pill-millipedes, Zephronia viridisoma Rosenmejer & Wesener sp. nov. and Sphaerobelum aesculus Rosenmejer & Wesener sp. nov., are described based on museum samples from southern Thailand. Zephronia viridisoma sp. nov. comes from Khao Lak, while the type locality of S. aesculus sp. nov. is on Phuket Island. Both species are described integratively, combining light microscopy, scanning electron microscopy, multi-layer photography, micro-CT scans and genetic barcoding. Genetic barcoding was successfully conducted for holotypes of both new species, which could be added to a dataset of all published sequences of the family Zephroniidae, including all described species from Thailand, Laos and Cambodia up to 2020. Genetic barcoding of the COI gene revealed another female of S. aesculus sp. nov., 160 km east of the type locality. Both new species are genetically distant from all other Zephroniidae from Thailand and surrounding countries, showing uncorrected p-distances of 16.8–23.1%. A virtual cybertype of a paratype of Z. viridisoma sp. nov. was created and made publically accessible.

Keywords: cybertype, CT Scan, DNA Barcoding, biodiversity, soil fauna


Class Diplopoda de Blainville in Gervais, 1844
Order Sphaerotheriida Brandt, 1833

Family Zephroniidae Gray, 1843
Remarks: See Wesener (2016a) for a catalogue of the family.


Map of Thailand, collection localities and habitus photographs:
Sphaerobelum aesculus sp. nov., ♀ (NHMD 621694);
Zephronia viridisoma sp. nov., paratype, ♀ (ZFMK MYR8787).
Scale bars = 1 cm.


Genus Sphaerobelum Verhoeff, 1924
Type species: Sphaerobelum clavigerum Verhoeff, 1924, from Vietnam.

Other taxa included: 18 species including the one described below
 (Semenyuk et al. 2018, 2020; Wesener 2019; Zhao et al.2020).

Distribution: Vietnam, Thailand, Laos, China.

Sphaerobelum aesculus Rosenmejer & Wesener sp. nov.

Diagnosis: Differs from all other species of the genus Sphaerobelum in the shape of the posterior telopod, where there is a swelling at the tip of the immovable finger, but the swelling does not extend above the margin (Fig. 5B arrow). Such a swelling is currently unknown from any other giant pill-millipede species.

Derivatio nominis: Named after the horse chestnut tree Aesculus hippocastanum L., for the resemblance of the rolled-up female to a horse chestnut. Noun in apposition.

Distribution: If the female from Khao Luang (Fig. 2A) is indeed conspecific with the male holotype, the species appears to have a wide area of distribution stretching from Phuket Island at least 160 km to the east (Fig. 2). Unpublished data from a larger inventory project (see, e.g., Wesener et al. 2021) of giant pill-millipedes in the surroundings of Krabi, half way between Phuket Island and Khao Luang, did not recover this species among the numerous specimens, hinting at a patchy distribution and specific microhabitat requirements of S. aesculus sp. nov.


Genus Zephronia Gray, 1832
Type species: Zephronia ovalis Gray, 1832.

Other taxa included: 44 species, including the one described below 
(Wesener 2016a, 2019; Semenyuk et al. 2018, 2020).

Distribution: NE India, Nepal, Myanmar, with a few species also in SE Asia.


Zephronia viridisoma Rosenmejer & Wesener sp. nov. 

Diagnosis: Posterior telopod typical for the genus, not differing from those of other Zephronia species. Small (25–28 mm long) green species (Fig. 2B), surface appearing glabrous, dull, with a single medium sized locking carina at the anal shield and a strongly projecting pleurite 1 (Fig. 9A). One of the few Zephroniaspecies with just a single apical spine on the legs (Fig. 9B), differing in this character from all other described Thai Zephronia species which have 2–5 apical tarsal spines. Male antennomere 6 swollen (Fig. 7A) but not axe-shaped, with < 50 apical cones. Endotergum with three dense rows of long marginal setae (Fig. 6B). Palpi of gnathochilarium with sensory cones arranged in clusters (Fig. 8C–D). Anterior telopod podomere 3 with an elevated process at posterior side carrying sclerotized teeth. Podomere 4 short and narrow.

Derivatio nominis: Named after the overall green colour of living individuals of the species, noun in apposition.


Trine Rosenmejer, Henrik Enghoff, Leif Moritz and Thomas Wesener. 2021. Integrative Description of New Giant Pill-Millipedes from southern Thailand (Diplopoda, Sphaerotheriida, Zephroniidae). European Journal of Taxonomy. 762(1); 108–132. DOI: 10.5852/ejt.2021.762.1457