Zephronia laotica, Wesener, 2019

Wesener, Thomas, 2019, First records of giant pill-millipedes from Laos (Diplopoda, Sphaerotheriida, Zephroniidae), Zootaxa 4563 (2), pp. 201-248 : 205-209

Zephronia laotica new species

Figures 2–4 .

Material examined: Type specimens. 1 M holotype (ZFMK MYR3502) from Laos, Champasak Province, east of Mekong, Garden of Erawan Riverside Hotel (N 15°6'27.0", E 105°49'14.3"), leg. Siegfried Huber, 10–15.xi.2012. 1 F paratype (ZFMK MYR8098), same data as holotype.

Diagnosis. Zephronia laotica n. sp. belongs to the Zephronia sensu stricto group based on the position of the organ of Tömösváry, located next to the aberrant ocelli, not inside the antennal groove (Semeyuk et al. 2018). Zephronia sensu stricto encompasses: Z. ovalis Gray, 1832 ; Z. konkakinhensis Semenyuk et al., 2018 ; Z. montis Semenyuk et al. 2018 from Vietnam; Z. siamensis Hirst, 1907 , the only species of the genus known from Thailand; and Z. dawydoffi Attems, 1953 , the only giant pill-millipede species known from Cambodia. Zephronia laotica n. sp. differs from Z. konkakinhensis and Z. montis in the walking legs that lack strong teeth on the femur, and Z. ovalis which has weak teeth at the mesal margin of the femur ( Fig. 3B ). Zephronia laotica n. sp. differs from Z. ovalis , Z. siamensis and Z. dawydoffi also in the differently shaped telopoditomeres 3 and 4 of the anterior telopods, the elongation of telopoditomere 3 and the small size of telopoditomere 4 are unique ( Figs 4 B–D), a different bright green colour of the tergites ( Fig. 2A ), leg 3 lacking an apical spine, and the presence of two locking carinae on each side of the anal shield.

Description. Based on holotype male and paratype female. Measurements: Holotype male. Body length = 15.6 mm. Width, of thoracic shield = 6.7 mm, of tergite 7 = 7.2 mm (= broadest). Height, of thoracic shield = 4.2 mm, of tergite 7 = 4.3 mm (= highest). Female: body length = ca 14.1 mm. Width, of thoracic shield = 6.1mm, of tergite 7 = 6.9 mm (= broadest). Height, of thoracic shield = 3.8 mm, of tergite 7 = 4.2 mm (= highest). Coloration: in preserved specimens, head and collum green. Tergites bright green, posterior half light brown. Antennae and legs green ( Fig. 2A ).

Head: wide and short. Eyes with>75 ocelli. Aberrant ocellus located inside antennal groove. Antennae short, with rounded joints, extending posteriorly to leg-pair 3. Sizes of antennomeres 1=2=3=4=5<<6. Antennomere 6 densely pubescent, with a few sensilla basiconica surrounding apical disc. Shape sexually dimorphic: in female cylindrical, in male laterally flattened, axe-shaped. Male apical disc with 61/65 apical sensory cones, that of female with 32/34 apical cones. Organ of Tömösváry located at a projected brim close to the ocelli at margin of antennal groove. Gnathochilarium: structure typical of the order. Sensory cones of palpi all located in single field. Mandibles not examined.

Stigmatic plates: first stigmatic plate triangular, apex broadly rounded, slightly curved towards coxa 1 ( Fig. 3A ). Laterotergites: first laterotergite tip weakly extended, pointed process. Second laterotergite with even shorter process, well-rounded apex. Collum: glabrous, except for margins which have a few isolated and long setae. Thoracic shield: surface as in tergites. Shallow grooves filled with numerous long setae, no keels. Tergites: surface shiny, glabrous, weakly coriaceous. Tips of paratergites of midbody tergites straight ( Fig. 2A ). Endotergum: inner section with few longer setae. Middle area with a single row of dense round, shallow, cuticular impressions; distance between impressions slightly smaller than their diameter. Apically, 1–2 dense rows of short marginal bristles, the longest just protruding above tergal margin. Bristles not smooth, but with numerous small spicules. Anal shield: slightly sexually dimorphic, in female large and well-rounded, in male more rectangular, in both sexes glabrous. Surface similar to that of tergites. Underside with two locking carinae; first short, as long as those of tergites, second as long as first, but much weaker. Legs: leg-pair 1 with 1 or 2 ventral spines, leg-pair 2 with 4, leg-pair 3 with 6. First three leg-pairs without an apical spine. Leg-pairs 4–21 with 7–9 ventral spines and 3–5 apical spines. In leg-pair 9, femur 1.5 times, tarsus 3.5 times longer than wide ( Fig. 3B ). All podomeres setose. Coxa with a large, well-rounded process. Coxal process absent on leg-pair 1 ( Fig. 3A ) and 2 ( Figs 3C , 4A ).

Female sexual characters: vulva small, covering 1/2 of coxa, located at mesal margin, extending mesally to basal third of prefemur length ( Fig. 3C ). Operculum rounded. Subanal plate: large, tall, triangular, with a wellrounded tip ( Fig. 3D ).

Male sexual characters: gonopore covered with a single, undivided, triangular, sclerotized plate ( Fig. 4A ). Anterior telopods ( Figs 4 B–D): first telopoditomere rectangular, slightly longer than wide. Telopoditomere 2 large, as long as telopoditomeres 3 and 4 combined. Process of telopoditomere 2 located posteriorly, but partly visible laterally in anterior view. Process of telopoditomere 2 wide, broader than telopoditomeres 3 and 4. Process of telopoditomere 2 wide, visible mesally in anterior view. Process of telopoditomere 2 tapering apically, wellrounded, protruding as high as basal part of telopoditomere 4. Telopoditomere 3 slender, 1.5 longer than wide, twice as long as telopoditomere 4. Telopoditomere 4 very short, in posterior aspect without any teeth, but with two prominent spines. All podomeres covered with long sparse setae, except for central part of telopoditomere 1 and posterior surfaces of 3 and 4. Posterior telopods ( Figs 4E, F ): first telopoditomere stout and narrow, twice as wide as long. Immovable finger (process of telopoditomere 2) as long as movable finger and consisting of telopoditomeres 3 and 4. Immovable finger wide, 1.9X longer than wide, weakly tapering apically, not curved. Margin towards movable finger genus-characteristic: with two large, triangular, membranous lobes, a spine, and several rows of circular sclerotized spots. Telopoditomere 3 elongated, typical of the genus: twice as long as telopoditomere 4. Margin near immovable finger with a large membranous lobe and a single long and slender spine, posterior surface with a row of 11 crenulate and sclerotized teeth. Telopoditomere 4 slender, only 2/3 as wide as telopoditomere 3, 2X longer than wide, slightly tapering apically. Telopoditomere 4 with at inner margin two long spines and a single membranous lobe. Entire telopod with few setae, mostly at margins at on anterior side of telopoditomere 2.

Derivatio nominis: laotica, noun in apposition, after Laos, as this is the first Zephronia known from this country.

Figures

FIGURE 2. Distribution map and habitus photograph of Zephronia species, Z. laotica n. sp.

FIGURE 3. Zephronia laotica n. sp., A, B: male holotype (ZFMK MYR3502); C, D: female paratype (ZFMK MYR8098); A: coxa of first left leg with first stigmatic plate; B: 9th right leg; C: coxa and prefemur of second left leg with vulva; D: subanal plate. Abbreviations: Cx = coxa; O = operculum of vulva; Pre = prefemur; St-Pl = stigmatic plate. Scale bars = 1 mm.

FIGURE 4. Zephronia laotica n. sp., male holotype (ZFMK MYR3502); A: coxa of second left leg with gonopore; B: left anterior telopod, anterior view; C: left anterior telopod, posterior view; D: left anterior telopod, lateral view; E: right posterior telopod, anterior view; F: right posterior telopod, posterior view. Abbreviations: Syn-Cx = syncoxite. Scale bars = 1 mm.