Research Article |
Corresponding author: Thomas Wesener ( twesener@uni-bonn.de ) Academic editor: Zoltan Korsós
© 2020 Irina Semenyuk, Sergei I. Golovatch, Thomas Wesener.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Semenyuk I, Golovatch SI, Wesener T (2020) Some new or poorly-known Zephroniidae (Diplopoda, Sphaerotheriida) from Vietnam. In: Korsós Z, Dányi L (Eds) Proceedings of the 18th International Congress of Myriapodology, Budapest, Hungary. ZooKeys 930: 37-60. https://doi.org/10.3897/zookeys.930.47742
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Three new species of the giant pill-millipede family Zephroniidae are described from southern Vietnam: Sphaerobelum pumatense sp. nov., Sphaeropoeus honbaensis sp. nov. and Sphaeropoeus bidoupensis sp. nov. Two species, Sphaerobelum bicorne Attems, 1938 and Sphaeropoeus maculatus (Verhoeff, 1924), are redescribed, the former from new material, the latter from type material with lectotype designation. A new transfer is proposed: Zephronia manca Attems, 1936, to the genus Sphaeropoeus Brandt, 1833, giving the new combination, Sphaeropoeus manca (Attems, 1936) comb. nov.
biological observations, giant pill-millipede, Sphaerobelum, Sphaeropoeus, taxonomy
The giant pill-millipede fauna (order Sphaerotheriida) of Southeast Asia is dominated by members of the family Zephroniidae (
The present paper puts on record another three new zephroniid species from Vietnam, provides redescriptions of two previously described species, and establishes a new combination.
Field work of author IS was conducted in accordance with Agreement 37/HD for the scientific cooperation between the Joint Russian-Vietnamese Tropical Centre and the Bidoup Nui Ba National Park and Hon Ba Nature Reserve, according to Agreement 1700/UBND.VX for the Pu Mat National Park, and to Agreement 308/SNgV-LS for the Song Thanh National Park. The Animal Care and Use Protocol Review No. 1723018 was strictly followed.
Material was collected in the Bidoup Nui Ba National Park during three field trips: 5–16 January, 12–21 June and 22–27 November 2018. The field work in the Hon Ba Nature Reserve was carried out from 23–29 June 2018, that in the Pu Mat National Park from 11–24 April 2018, while that in the Song Thanh National Park was from 23 April to 11 May 2019. Millipedes were obtained in forest or rural habitats by hand-sorting the leaf litter, visual spotting on open places, and through the examination of spaces under logs and stones. Collecting was performed in daylight, as well as at night. Ecological and behavioral data were recorded while collecting. Pictures of living animals were taken with a Panasonic DMC-TZ80 - LUMIX Digital Camera. Animals were preserved in 75% ethanol.
For illustrations, the 9th legs and both anterior and posterior telopods were removed from males with forceps. Female vulvae were dissected from leg-pair 2 on one side of the body (not dissected in one species). Antennae were examined for all species where females were available, and male antennae were illustrated without removing the head. An Olympus SZ61 stereo microscope was used for observation and capturing images for the line drawings; sketches were scanned with a CanoScan Lide 60 scanner and then edited with Corel Photo-Paint X5 software. The terminology of morphological characters follows
Left antennae, endoterga and terga were dissected. The samples were cleaned and dehydrated via an ethanol series (2× 96%, 3× 100%) prior to mounting on aluminum SEM stubs. The samples were coated with gold for 240 seconds in a sputter coater. SEM images were then taken using a Supra VR 300VP (Carl Zeiss AG, Oberkochen, Germany) scanning electron microscope utilizing SmartSEM V05.00 software based at the
Class Diplopoda de Blainville in Gervais, 1844
Order Sphaerotheriida Brandt, 1833
Family Zephroniidae Gray in Jones, 1843
See
Sphaerobelum bicorne
Attems, 1938: 200;
1 ♂, 1 ♀ (
Sphaerobelum bicorne belongs to the group of congeners in which the mesal margin of the femur is extended into several teeth. Sphaerobelum bicorne shares only with S. bolavensis Wesener, 2019, from Laos (
Body length
: ♂ length ca. 40.9 mm, width of thoracic shield 21.3 mm, of tergite 8, 21.9 mm (= broadest), height of thoracic shield, 12.1 mm, of tergite 8, 13.3 mm (= highest); ♀ length ca. 42.7 mm, width of thoracic shield, 23.5 mm, of tergite 7, 24.3 mm (= broadest), height of thoracic shield 11.9 mm, of tergite 8, 15.1 mm (= highest). ZMUM adults 18 (♂) to 23 mm wide (♀). Coloration: both in vivo and in vitro, after several months of preservation in ethanol, uniformly black to blackish, shining. Head and collum also black. Antennae orange, legs in life mainly blackish as well (Fig.
Live Sphaerobelum pumatense sp. nov. (A–C) and Sphaerobelum bicorne Attems, 1938 (D–H) in the field A–C adult, enrolled, ventral view and walking, respectively D–F adults, ventral view, and enrolled, respectively G, H juvenile, enrolled and unrolling, respectively. Pictures taken not to scale.
In the field, these millipedes were found in a very wide range of habitats, from 700 to 1200 m a.s.l., including extremely humid forest on river banks and in valleys with abundant Cyathea sp. tree ferns, on sandy soils and in sparse leaf litter; on hill slopes covered with rich broadleaved tropical forest and a thick leaf litter layer; as well as on very dry ridges and interfluves with broadleaved forest with admixtures of coniferous trees, and in open places colonized by Dicranopteris sp. ferns and Melastoma sp. bushes. A similar number of males and females were recorded during the expedition (30 adult individuals in total). Two-thirds of the females were hidden in leaf litter inside their “living chambers”, the remaining were spotted walking on the forest floor. All males were likewise walking on the forest floor, most probably searching for mates. The few recorded juveniles of both sexes were hidden in leaf litter. During the expedition, the day temperature on the leaf litter surface averaged 24 °C, compared to 19 °C in the night, with occasional nights when the temperature dropped down to 17.5 °C. Heavy, but rather short showers took place almost every day, quite often also with fogs in the evening. The abundance of the millipedes did not change drastically under rains, only slightly decreasing on non-rainy days in open habitats.
According to local knowledge, April is the driest month in the Park, while the rest of the year is extremely humid. Surprisingly, we noticed the lack of Diplopoda during the expedition with very little millipede activity, but S. bicorne was abundant at different age stadia. It may be a strategy for avoiding competition with other millipede species, as Sphaerobelum is a quite robust and well-protected diplopod capable of surviving difficult conditions.
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.
Holotype
♂ (ZMUM Rd 4647), Vietnam, Nghe An Prov., Pu Mat National Park, 18°56'N, 104°38'E, 200 m a.s.l., mixed tropical forest on steep slopes, on forest floor, daytime, IV.2018, I.I. Semenyuk leg. Paratypes 1 ♂, 1 ♀ (ZMUM Rd 4632), 1 ♂, 2 ♀ (ZMUM Rd 4648), 1 ♂, 1 ♀ (
Sphaerobelum pumatense sp. nov. belongs to the group of congeners in which the mesal margin of the femur is extended into several teeth (Fig.
Endoterga of midbody segments, SEM micrographs. A Sphaerobelum bicorne Attems, 1938, ♂ (
Body length
: holotype ♂ length ca. 27.2 mm, width of thoracic shield 15.61 mm, of tergite 7 (= broadest), 15.5 mm, height of thoracic shield, 7.9 mm, of tergite 7 (= highest), 8.2 mm; ♀ length ca. 34.8 mm, width of thoracic shield, 17.2 mm, of tergite 7, 17.9 mm (= broadest), height of thoracic shield, 9.5 mm, of tergite 7, 9.9 mm (= highest). Width of paratypes 14–17 (♂) or 15–17 mm (♀). Coloration: both in vivo and in vitro, after >1.5 years of preservation in ethanol, similar, uniformly dark blackish brown, dark chestnut, dark grey-brown or dark reddish brown, in alcohol with posterior margin usually dark brown, paratergite depressions, groove of thoracic shield and legs dark olive to olive-brown, but several basal podomeres and distal halves of tarsi considerably lighter, orange. Antennae blackish to dark brown, but antennomeres 5 and 6 lighter, light brown to nearly orange. Tegument mosly dull to poorly shining (Fig.
To emphasize the provenance from the Pu Mat National Park, adjective.
In the field, the weather was fluctuating between very dry and hot days and several rainy days, with day temperature above the leaf litter averaging 24 °C, and night temperature averaging 21 °C, not dropping below 18.5 °C. Sphaerobelum pumatense were quite rare in any weather conditions. The millipedes were found in forests ranging from 150 m to 400 m a.s.l., the forest canopy appeared to have been free of this species. Females were mostly hidden in leaf litter in small patches of litter on very steep slopes (60–70°), forming “living rooms”, choosing places with water oozing from beneath shale so that the leaf litter was constantly wet. Males were found mainly on the forest floor at night. No juveniles were seen.
Sphaerobelum bicorne Attems, 1938, ♂ (A–G) and ♀ (H) from Song Thanh National Park. A, B Right posterior telopod, anterior and posterior views, respectively C, D right anterior telopod, posterior and anterior views, respectively E telopoditomeres 2 and 3 of right anterior telopod, lateral view F left leg 9, anterior view G left antenna H left coxa and prefemur 2 with vulva, posterior view. Scale bars: 1.0 mm, E drawn not to scale.
See
Remarks. A large gap between the tarsal claw and apical spine as observed in the three species of Sphaeropoeus studied here, as well as in the two (including the type species S. hercules Brandt, 1833) redescribed recently (
Zephronia manca
Attems, 1936: 169;
♂ and ♀,
Vietnam: D’Ran, Lam Dong Prov., near Dalat; Peak Lang Biang, Lam Dong Prov., S. Annam. India: Dhobie Jhora, Kurseong, eastern Himalayas (
Sphaerobelum pumatense sp. nov., ♂ holotype (A–G) and ♀ paratype (H). A, B Left posterior telopod, anterior and posterior views, respectively C–E left anterior telopod, anterior, lateral and posterior views, respectively F left leg 9, anterior view G left antenna H left coxa and prefemur 2 with vulva, posterior view. Scale bars: 1.0 mm, D drawn not to scale.
The drawings of the telopods, as well as the extremely enlarged operculum of the ♀ vulva as depicted in the original description (
Tonkinobelum maculatum Verhoeff, 1924: 62;
Sphaeropoeus maculatus―
Lectotype ♂ (HNMB 2858/1), designated here to fix the name for future studies and to avoid taxonomic confusion. Vietnam, ‘Tonkin’, Mau Son (= Mau Son Mountains, Lang Son Province), H. Fruhstorfer leg.
Measurements
: ca. 58 mm long, 23.1 mm (2nd), up to 23.9 mm (8th) wide, 13.5 mm (2nd) up to 15.1 mm height (8th the highest). Coloration: apparently faded after more than 90 years in ethanol. Head, collum and appendages dark green, remaining tergites castaneous brown. Head: eyes with >70 ocelli. Antennae very short, protruding up to centre of head. Antennomeres 1–5 with few longer setae, 6th densely pubescent. Antennomere 6 towards disc with a single row of sensilla basiconica. Antennomere 6 strongly axe-shaped, twice as wide as antennomeres 1–5. ♂ with >140 apical cones. Palpi of gnathochilarium located in a single field. Collum: glabrous except for anterior edges. Thoracic shield: with wide and deep grooves, 3 or 4 weak crests present at posterior corner. Tergites: surface glabrous and smooth except for paratergite depressions. Midbody paratergite tips projecting posteriorly. Anal shield: well-rounded, glabrous. Locking carinae rudimentary, very short, located close to last laterotergite. Endotergum: inner section lacking any spines or setae. Middle area lacking discernible cuticular impressions. Apically, 3–4 very dense rows of short marginal bristles, tips of longest setae barely protruding beyond midpoint towards tergal margin (Fig.
Verhoeff described the species based on four syntypes. Only one syntype could be relocated; the others may be considered as likely lost. As the sole available syntype is a mature ♂ in very good condition, this specimen has been designated as the lectotype. ♀ unknown.
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 ♂ (
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.
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.).
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.
Sphaeropoeus bidoupensis sp. nov., ♂ holotype (A–H) and ♀ paratype (I). A, B Left posterior telopod, posterior and anterior views, respectively C–F left anterior telopod, posterior, sublateral, lateral and anterior views, respectively G left leg 9, anterior view H left antenna I left coxa and prefemur 2 with vulva, posterior view. Scale bars: 1.0 mm, D drawn not to scale.
To emphasize the provenance from the Hon Ba Nature Reserve, adjective.
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.
Holotype
♂ (ZMUM Rd 4646), Vietnam, Lam Dong Prov., Bidoup Nui Ba National Park, 12°10'N, 108°41'E, 1500 m a.s.l., mixed tropical forest on hills, in leaf litter, daytime, VI.2018, I.I. Semenyuk leg. Paratypes 1 ♂, 2 ♀ (ZMUM Rd 4634), 1 ♂ (
Sphaeropoeus bidoupensis sp. nov. differs from almost all other known continental species of the genus in the anterior telopod showing a very short, almost completely reduced telopoditomere 4, a character only shared with S. honbaensis sp. nov. Sphaeropoeus bidoupensis sp. nov. differs from S. honbaensis sp. nov. in the presence of a spine in the inner area of the large telopoditomere 3 (vs. absent in S. honbaensis sp. nov.), in the endotergum, where the distances between the cuticular impressions are slightly smaller than the diameter (vs. wider than diameter in S. honbaensis sp. nov.), the ♂ anal shield being well-rounded (weakly bell-shaped in S. honbaensis sp. nov.), and in leg structure, with leg-pair 3 having an apical spine (vs. absent in S. honbaensis sp. nov.), the prefemur showing a dentate mesal margin (vs. smooth in S. honbaensis sp. nov.), and the coxa process being weakly developed and partly sharp (vs. strongly developed and well-rounded in S. honbaensis sp. nov.).
Measurements
: holotype ♂ ca. 24 mm long, 11.2 mm (2nd), up to 12.3 mm (7th) wide, 7.1 mm high (2nd the highest). Paratype ♀ (
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.
To emphasize the provenance from the Bidoup Nui Ba National Park, adjective.
This new species was very abundant in the Park area and could be found almost throughout the year. In January, juveniles lived under logs, but no adults were recorded. The daytime temperature above the leaf litter averaged 17 °C, dropping down to 14 °C (minimum 12.5 °C) at night; rains were quite abundant. In June, juveniles colonized decaying wood, leaf litter, suspended soils in Asplenium sp. ferns, and spaces under logs. Adults lived in leaf litter and the suspended soil of ferns, only occasionally and only males walking openly on the forest floor. Juveniles and some adults were often recorded hiding inside their “living chambers” (Fig.
Sphaeropoeus bidoupensis sp. nov. seems only to occur in forests at about 1500 m a.s.l.. This was a riparian, very wet, broadleaved forest with abundant Asplenium sp. ferns on tree trunks starting from the ground level and a thick leaf litter layer on the floor, as well as a forest with dominating Fagaceae trees mixed with several coniferous species on slopes, the leaf litter layer being thick and to a significant proportion formed by coniferous needles. The species was not located in the adjacent mossy elfin forest up to 2000 m a.s.l. with a much cooler and wet weather.
Zephroniidae in Vietnam, currently amounting to seven species of Sphaerobelum, five species in Zephronia, four in Sphaeropoeus, three in Prionobelum and one species in Cryxus, are distributed in the north as well as the south of the country (Fig.
Our contribution reinforces the impression that Vietnam, together with the adjacent parts of Laos, represents one of the main hotspots of zephroniid/sphaerotheriidan diversity not only in Indochina, but also in the entire Southeast Asia. Despite the considerable recent progress achieved in the study of Sphaerotheriida in Indochina (
We wish to express our cordial thanks to the Vietnamese and Russian colleagues who supported and helped IS during her field trips to the different national parks or nature reserves concerned. Both Zoltan Korsós and Eszter Ágnes Lazányi-Bacsó (HNHM) very kindly arranged the type of Sphaeropoeus maculatus on loan. We are also very grateful to Thorsten Klug (