Sphaeropoeus honbaensis, Semenyuk & Golovatch & Wesener, 2020

Semenyuk, Irina, Golovatch, Sergei I. & Wesener, Thomas, 2020, Some new or poorly-known Zephroniidae (Diplopoda, Sphaerotheriida) from Vietnam, ZooKeys 930, pp. 37-60 : 37

Sphaeropoeus honbaensis sp. nov. Figs 2F-H , 3E , 8

Material examined.

Holotype ♂ (ZMUM Rd 4644), Vietnam, Khanh Hoa Prov., Hon Ba Nature Reserve, 12°07'N, 108°56'E, 1550 m a.s.l., mixed mossy tropical forest on mountain ridge, on forest floor, night time, VI.2018, I.I. Semenyuk leg. Paratypes 2 ♂ (ZMUM Rd 4633), 1 ♂ (ZFMK MYR8943), same locality as holotype. 1 ♀ (ZMUM Rd 4645), same locality, 1450 m a.s.l., mixed tropical forest on mountain slope, in leaf litter, day time, VI.2018, I.I. Semenyuk leg.

Diagnosis.

Sphaeropoeus honbaensis sp. nov. differs from all other known continental species of the genus in the presence of very few (<30) apical cones on the ♂ antenna (usually at least>70, often>120). The anterior telopod also shows a very short, almost completely reduced telopoditomere 4, a character only shared with S. bidoupensis sp. nov. Sphaeropoeus honbaensis sp. nov. differs from S. bidoupensis sp. nov. in the lack of a spine in the inner area of the large telopoditomere 3 (vs. present in S. bidoupensis sp. nov.), in the endotergum, where the distances between the cuticular impressions are wider than the diameter (vs. slightly narrower than diameter in S. bidoupensis sp. nov.), the ♂ anal shield being weakly bell-shaped (vs. well-rounded in S. bidoupensis sp. nov.), and in leg structure, with leg-pair 3 lacking an apical spine (vs. present in S. bidoupensis sp. nov.), the prefemur lacking a dentate mesal margin (vs. present in S. bidoupensis sp. nov.), and the coxa process being strongly developed and well-rounded (vs. weakly developed and partly sharp in S. bidoupensis sp. nov.).

Description.

Measurements: holotype ♂ ca. 27 mm long, 12.1 mm (2nd), up to 12.2 mm (7th) wide, 7.8 mm (2nd) up to 15.1 mm height (8th the highest); ♂ paratypes 8-11 mm wide. Paratype ♀ ca. 29 mm long, 13.1 mm (2nd), up to 13.3 mm (7th) wide, 7.8 mm (2nd) up to 8.4 mm height (7th the highest). Coloration: both in vivo and in vitro, after>1.5 years of preservation in ethanol, similar, in life uniformly dark violet brown to violet blackish with vague infuscate bands near caudal margin (Fig. 2F-H ), in alcohol dark brown to brown, in places marbled, only dorsalmost part of anal shield sometimes lighter centrally, light brown. Antennae orange. Legs mostly grey- or olive-brown, but tarsi yellow-brown. Tegument mosly dull to poorly shining. Head: eyes with ca. 65 ocelli. Antennae short (Fig. 8A ), protruding beyond centre of head. Antennomeres 1-5 with few longer setae, 6th densely pubescent. Antennomere 6 towards disc with single row of sensilla basiconica. Antennomere 6 slightly swollen in ♂, cylindrical in ♀, twice as long as, but only slightly wider than, antennomeres 1-5. ♂ with 26/27, ♀ with 22/24 apical cones. Palpi of gnathochilarium located in a single field. Collum: completely covered with long setae, like the tergites. Thoracic shield: with wide and shallow grooves, 3 or 4 weak crests present at posterior corner. Tergites: surface covered with longer setae, most innervating in small pits. Midbody paratergite tips projecting posteriorly (Fig. 10 ). Anal shield: well-rounded in ♀, weakly bell-shaped in ♂. In both sexes completely covered with longer setae. Locking carina long, twice as long as width of last laterotergite, located close to margin. Endotergum: inner section lacking any spines or setae. Middle area with a single row of large, sparse, elliptical, cuticular impressions. Distance between impressions greater than their diameter. Apically, two rows of long marginal bristles, tips of longest setae clearly protruding beyond tergal margin (Fig. 3E ). Bristles not smooth, but with numerous small spinicles. Stigmatic plates: first well-rounded, triangular. Laterotergites : first with a slightly projecting, well-rounded process. Laterotergites 2 and following not extended, well-rounded. Legs: first with 2 or 3, second with 3 or 4, third with 8 ventral and lacking an apical spine. Leg-pairs 4-21 each with 10-12 ventral spines and a single apical spine. Coxa process visible, well-rounded (Fig. 8B ). Femur 1.7, tarsus 5.2 × as long as wide. Femur with a very long ridge (Fig. 8B ). Mesal margin of femur completely extended into 12-14 teeth, lateral margin of prefemur, juxtaposed to coxal process, slightly extended into 2-4 teeth (Fig. 8B ). Female sexual characters: vulva large, covering 2/3 coxa, a conspicuous operculum extending to basal half of prefemur (Fig. 8H ). Operculum massive, larger than bursa, wider than prefemur, apically rounded, mesal margin very slightly projecting and slightly higher than remaining operculum. Subanal plate: large and wide, triangular. Male gonopore: opening covered with a single, apically membranous plate. Anterior telopod (Fig. 8E-G ): four podomeres, first three of equal length regardless of the processes, podomere 4 rudimentary, conical. Telopoditomere 2 with a strong, curved process overreaching telopoditomere 4. Telopoditomere 3 posteriorly with a longer process juxtaposed to apex process of telopoditomere 2, clearly protruding above telopoditomere 4, as well as process of telopoditomere 2. Telopoditomere 4 conical, with two spines. Posterior telopod (Fig. 8C, D ): Podomeres 3 and 4 slightly longer than process of podomere 2. Podomere 4 short, conical, with two spines, slightly curved towards immovable finger. Podomere 3 slender, 4.2 times longer than wide. Its excavate inner margin with a membranous lobe and a single spine, posterior aspect with ca. 12 small crenulated teeth. Immovable finger slender, apically tapering, tip curved towards movable finger. Membranous area apically with a large membranous lobe. Podomeres 1-3 in anterior and posterior views with few setae. Podomere 4 in both aspects glabrous.

Etymology.

To emphasize the provenance from the Hon Ba Nature Reserve, adjective.

Remarks.

During the expedition, more than ten males of this species were recorded, all walking on the forest floor in the night, mainly on the mountain ridge. Only one adult female was found despite special searching efforts: it was hidden in leaf litter, which is typical of sphaerotheriidans. The female was encountered in a forest at an elevation considerably lower than the where abundant males were observed. Although confusing, this may be accounted for by high population abundance at the onset of a season. During the expedition, it was raining almost every day, the temperature in the daytime above leaf litter averaging 20 °C and dropping down to 17.5 °C (minimum 16.8 °C) at night. Fog was very often seen on the top of the mountain. No juveniles were recorded.

Figures

Figure 2. Live Sphaeropoeus bidoupensis sp. nov. (A-E) and Sphaeropoeus honbaensis sp. nov. (F-H) in the field A enrolled male (left) and female (right) B adult, ventral view C adult and its excrements in a " living room " in leaf litter D early instar juvenile enrolled in its " living room ", with surrounding dead leaves eaten and excrement used to shape the room E enrolled middle-sized instar juvenile F-H adult, enrolled and walking, respectively. Pictures taken not to scale.

Figure 3. Endoterga of midbody segments, SEM micrographs. A Sphaerobelum bicorne Attems, 1938, ♂ (ZFMK) B Sphaerobelum pumatense sp. nov., ♂ holotype C Sphaeropoeus maculatus (Verhoeff, 1924), ♂ lectotype D Sphaeropoeus bidoupensis sp. nov., ♂ holotype E Sphaeropoeus honbaensis sp. nov., ♂ holotype. Scale bars: 0.2 mm.

Figure 8. Sphaeropoeus honbaensis sp. nov., ♂ holotype (A-G) and ♀ paratype (H). A Left antenna, B left leg 9, anterior view C, D left posterior telopod, posterior and anterior views, respectively E-G left anterior telopod, anterior, posterior and lateral views, respectively H left coxa and prefemur 2 with vulva, posterior view. Scale bars: 1.0 mm, G drawn not to scale.

Figure 10. Habitus photograph of the lectotype (HNHM 2858 / 1) of Sphaeropoeus maculatus (Verhoeff, 1924), lateral view, and a distribution map of all other relevant zephroniid species in Vietnam. A Sphaerobelum bicorne Attems, 1938 (new record) B Sphaerobelum bicorne Attems, 1938 (old record) C Sphaerobelum pumatense sp. nov. D Sphaeropoeus manca (Attems, 1936) E Sphaeropoeus maculatus (Verhoeff, 1924) F Sphaeropoeus honbaensis sp. nov. G Sphaeropoeus bidoupensis sp. nov.