Zephronia erawani Bhansali &Wesener, 2022

Bhansali, Sneha & Wesener, Thomas, 2022, New Thai giant pill-millipede species, with new genetic barcoding data (Diplopoda Sphaerotheriida, Zephroniidae), Zootaxa 5105 (3), pp. 357-380 : 370-374

Zephronia erawani Bhansali &Wesener , new species

Figures 2A, 12, 13, 14.

Diagnosis. The position of the organ of Tömösváry at the brim and not in the antennal groove identifies this species as a member of the Zephronia senso-stricto group with which it also aligns weakly genetically. The sensory cones on the palpi of the gnathochilarium are arranged in a single field, not in separate clusters and the body is covered in a dense coat of golden setae like in several other Thai Zephronia . The greyish-brown color resembles those of Z. chrysomallos sp. nov. and Z. panhai . The male second leg mesal coxal margin is extended into a membranous process ( Fig. 13B arrow), a character shared only with Z. golovatchi and Z. enghoffi . Z. erawani sp. nov. differs from both Z. golovatchi and Z. enghoffi in the shorter marginal bristles of the endotergum which end well before the margin, while the bristles are projecting above the two in both other species.

Z. erawani sp. nov. differs genetically in the COI barcoding fragment from Z. panhai by a p-distance of 11.6%, from Z. chrysomallos sp. nov. by a p-distance of 11.9% and from Z. lannaensis by 12.6–13.3% (Sup. file 1).

Derivatio nominis. Named after the type locality, the Erawan waterfalls. Erawan is a mythological elephant, similar to the Hindi Airavata. Noun in apposition.

Material examined (total: 1 ♂)

Holotype:

THAILAND: 1 ♂, NHMD K56-9, Kanchanaburi Province, Si Sawat District, 50 km W of Kanchanaburi, Erawan Waterfall , [probably: 14°21'31.32"N, 99° 8'26.23"E, 377 m], 6.VI.1990, leg. A. R. Rasmussen & B. Helwigh.

Description (based on holotype)

Size. Length: 31.4 mm. Width of thoracic shield 14.8 mm, of widest segment (6) 16.5 mm. Height of thoracic shield 9.3 mm, of highest segment (6) 9.8 mm.

Colour. Faded after 30 years in 75% ethanol. Collum medium brown, head and legs with traces of green. Antenna green. Tergites and anal shield pale greyish-brown, darker brown towards posterior margin. Thoracic shield-like tergite with darker groove and margins. Anal shield colour like tergite.

Head. Number of ommatidia 95. Tömösváry organ placed on the rim of antennal groove. Antennae short, not reaching to center of head ( Fig. 12A–D). Antennomere lengths: 1>2=3=4=5<<6. Antennomer 6 laterally flattened, apically widened, axe-shaped, carrying 91/96 apical cones.

Epipharynx. Not dissected.

Gnathochilarium ( Fig. 12D). Gnathochilarium palpi with the sensory cones arranged in single field.

Mandible. Not dissected.

Collum. Numerous setae, distributed towards margins, few setae in central region.

Thoracic shield. Thoracic shield grooves shallow and wide with 2 or 3 weak ledges ( Fig. 12A, B).

First stigmatic plate. Smaller than coxa, rounded apex.

Tergites. Tergites covered in short, dense setae visible at higher magnification, with dull orange skin-like surface. Paratergite tips weakly projecting backwards ( Fig. 12A, B).

Pleurites ( Fig. 12C). Pleurite 1 projecting, tip well-rounded. Pleurite 2 well-rounded, weakly projecting.

Endotergum. With a regular flat margin. Outer zone with three dense rows of irregular marginal setae, not extending beyond posterior margin, but reaching 4/5 of the outer area. Middle section with cuticular impressions. Inner area without setae.

Legs. Ventral spines on leg 1 2/2, at 2 4 /4, at 3 7/7. Leg 3 with single apical spine. Mid-body legs with 2 or 3 apical and 8–10 ventral spines ( Fig. 13A). Inner margin of femur with 14 small triangular teeth, concentrated at apical half, but not excavated. Femur 1.7, tarsus 3.6 times longer than wide.

Anal shield. Bell-shaped and like tergites covered with short dense setae visible at higher magnification. Underside with single black locking carina of medium length, located close to pleurite ( Fig. 12C).

Male gonopore. Located directly on mesal margin of coxa 2, covered posteriorly by a single semicircular sclerotized plate. Membrane rising mesally into a projection ( Fig. 13B).

Anterior telopods ( Fig. 13C–E). Syncoxite with few setae. Podomere 1 rectangular, as long as wide. Numerous setae, mainly at median margins. Podomere 2 slightly narrower than podomere 1. Process massive, well-rounded, apically slightly tapering, relatively short and wide ( Fig. 13D, E). Process visible protruding and exceeding podomere 3 in anterior view ( Fig. 13D). Podomere 3 cylindrical, with a black spot at the anterior margin visible in posterior view. Podomere 4 partially fused to podomere 3, suture can be seen in anterior view ( Fig. 13C), while it is completely fused in posterior, lateral and mesal views. Podomere 4 small, narrowing at the apex. Meso-anterior margin with one spine and a black spot at apex visible in posterior and lateral view.

Posterior telopods ( Fig. 14). Syncoxite inner horns (not drawn): apex well rounded, apically diverging. Podomere 1 with short setae distributed in median and lateral margin, median margin glabrous. Podomere 2 with long and wide immovable finger, 2.5 times longer than wide. Podomere 2 with numerous setae visible in anterior view, almost entirely glabrous in posterior view. Immovable finger slightly narrow anteriorly and straight. Apical process with sclerotized round spots in anterior view ( Fig. 14A, arrow). Membrane toward podomere 3 with a two-tipped membranous lobe. Podomere 3 setose in anterior view, with more setae concentrated medially. With row of 15 large, crenulated teeth on posterior side ( Fig. 14B, arrow). Large membranous ledge on podomere 3 with single spine present basal region. Podomere 4 glabrous on both sides, slightly curved towards immovable finger. Membranous lobe with 2 long spines. Immovable finger shorter than movable finger.

Distribution

Z. erawani sp. nov. is currently only known from the type locality ( Fig. 2A) and might be microendemic, as are other, closely related species in nearby forests.