Research Article |
Corresponding author: Natdanai Likhitrakarn ( kongerrrr@hotmail.com ) Academic editor: Pavel Stoev
© 2021 Ruttapon Srisonchai, Chirasak Sutcharit, Natdanai Likhitrakarn.
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:
Srisonchai R, Sutcharit C, Likhitrakarn N (2021) The giant pill-millipede genus Zephronia Gray, 1832 from Thailand, with a redescription of Z. siamensis Hirst, 1907 and descriptions of three new species (Diplopoda, Sphaerotheriida, Zephroniidae). ZooKeys 1067: 19-56. https://doi.org/10.3897/zookeys.1067.72369
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Material of the giant pill-millipede genus Zephronia Gray, 1832 recently collected from Thailand contains three new species: Zephronia enghoffi sp. nov., Zephronia golovatchi sp. nov., and Zephronia panhai sp. nov. The first Zephronia species recorded for Thailand, Z. siamensis Hirst, 1907, is also redescribed based on new specimens collected both from the type locality in Chonburi Province and from neighboring areas. Morphological characters of all new species, Z. phrain Likhitrakarn & Golovatch, 2021, and Z. siamensis are illustrated, and a distribution map of the confirmed Zephronia species occurring in Thailand is also provided.
Diplopods, key, map, Southeast Asia, taxonomy
One of the remarkable diplopod groups, the giant pill-millipede genus Zephronia Gray, 1832 is one of the most speciose not only in the family Zephroniidae, but also in the entire order Sphaerotheriida. It currently contains 44 described species ranging from the Himalayas of India in the west, to mainland Southeast Asia in the east (
The millipedes were collected by active search in daytime during the field trips in Thailand. All material was collected by ASRU (Animal Systematics Research Unit) members. Live specimens of both sexes were photographed with a Nikon D700 camera equipped with a AF-S VR Micro-Nikkor 105 mm lens. Specimens were then euthanized based on the methods of AVMA guidelines for the euthanasia of animals (
All morphological characters were analyzed under a NIKON SMZ-445 stereo microscope. For Scanning Electron Microscopy (SEM), the specimens were mounted on aluminum stubs, coated with pure gold and studied using a JOEL JSM-6610LV scanning electron microscope. The descriptions are applied to both males and females. Species delimitation and morphological descriptions were based on
All material of each species is referred to each species description. The holotypes are deposited in the Chulalongkorn University Museum of Zoology (
cp cuticular impression
cr-T crenulated teeth
cx coxa
is inner section
ML membranous lobe
ms middle section
o operculum of vulva
ot outer section
pm posterior margin
pre prefemur
sp sclerotized process
st-pl stigmatic plate
syn-cx syncoxite
ASRU Animal Systematics Research Unit, Chulalongkorn University, Thailand
a.s.l. above sea-level
ca. about, around, circa
CUMZ Chulalongkorn University Museum of Zoology, Thailand
Koh the Thai word for “island”
NHMD Natural History Museum of Denmark, University of Copenhagen, Denmark
Wat the Thai word for “temple”
ZMUM Zoological Museum, State University of Moscow, Russia.
See the details in species descriptions by
Subfamily Zephroniinae Gray, 1843
Tribe Zephroniini Jeekel, 2001
See complete and recently updated diagnoses in
1. Zephronia siamensis Hirst, 1907 2. Zephronia lannaensis Likhitrakarn & Golovatch, 2021 3. Zephronia phrain Likhitrakarn & Golovatch, 2021 4. Zephronia viridisoma Rosenmejer & Wesener, 2021 5. Zephronia enghoffi sp. nov. 6. Zephronia golovatchi sp. nov. 7. Zephronia panhai sp. nov.
Zephronia cf. viridescens Attems, 1936.
Zephronia siamensis
Hirst, 1907: 218;
Zephronia cf. siamensis
–
Thailand – Chonburi Province • 2 ♂♂ 17 ♀♀; Sichang District, Koh Sichang; 13°9'3.8"N, 100°48'56"E; 7 m a.s.l.; 14 November 2020; R. Srisonchai, N. Likhitrakarn, P. Jirapatrasilp leg.; • 2 ♀♀; same collection data; NHMD • 2 ♀♀; same collection data; ZMUM • 3 ♀♀; same Province, Mueang District, Grand Cayon Chonburi; 12°31'23"N, 100°57'18"E; 7 m a.s.l.; 2 August 2019; ASRU members leg.; • 1 ♀; same Province, Sattahip District, Koh Chuang; 12°31'23"N, 100°57'18"E; 7 m a.s.l.; 8 August 2013; R. Srisonchai, P. Jirapatrasilp leg.; • 2 ♀♀; same Province, Bo Thong District, Wat Tham Khao Cha-ang-on; 13°12'31.7"N, 101°39'5.7"E; 128 m a.s.l.; 4 July 2016; R. Srisonchai, P. Tongkerd leg.; • 1 ♀; Rayong Province, Mueang District, Koh Samet; 12°34'22.6"N, 101°27'52.6"E; 128 m a.s.l.; 12 January 2010; ASRU members leg.
Kosichang and Chantaboon, Siam (
A member of Zephronia s. s. in which the position of Tömösváry’s organ located next to the aberrant ommatidia, not inside the antennal groove. Adult body length relatively small, usually ca. 20 mm, < 26.5 mm, tip of subanal plate concave, process of telopoditomere 2 of anterior telopod rather short and strongly curved distally, and process of telopoditomere 2 of anterior telopod shorter than the combination of telopoditomeres 3 and 4. Similar in these respects to Z. laotica Wesener, 2019 and Z. dawydoffi Attems, 1953. Differs from these two species by showing a body length > 16.7 mm, live specimens with unique dark green, tergites with two yellow-brown patches located in anterior half of tergites, surface of tergites with conspicuous setae, femur of leg extended with conspicuous teeth, and telopoditomere 4 of anterior telopods posteriorly with a row of conspicuous crenulated teeth (cr-T).
Body size : Male: body length 15.0–26.5 mm. Width of thoracic shield 9.0–12.5 mm, of tergite 8 9.5–11.4 mm. Height of thoracic shield 5.2–6.4 mm, of tergite 7, 6.1–7.4 mm. Female: body length 15–23.0 mm. Width of thoracic shield ca. 12.1 mm, of tergite 8 ca. 12.8 mm. Height of thoracic shield ca. 7.3 mm, of tergite 7 ca. 8.2 mm.
Color
(Fig.
Head : Trapezoid, anterior part of head clothed with numerous long setae, posterior part sparsely punctate; anterior margin of labrum with a single tooth. Each eye with 75–92 ommatidia. Aberrant ocellus located inside antennal groove.
Antennae
(Fig.
Tömösváry’s organ : Located separately at a small, projected brim between ommatidia and antennal socket.
Gnathochilarium : Ventral surface with setae, other structures typical of the order. Palpi with sensory cones arranged in clusters. Mandibles not dissected.
Stigmatic plates
(Fig.
Laterotergites : 1 and 2 with a broad and well-rounded projection.
Collum : With glabrous surface, sparsely setose with very long setae, except for anterior and posterior margins which are densely setose.
Thoracic shield : Surface with tiny setae as on tergites. Shallow grooves filled with numerous long setae, no keels.
Tergites
(Fig.
Endotergum
(Figs
Anal shield : Sexually dimorphic, in female large and well-rounded, in male slightly more rectangular, in both sexes glabrous. Surface similar to that of tergites. Inner surface (underside) with a single, long, black locking carina half as long as width of last laterotergite.
Legs
(Fig.
Subanal plate
(Fig.
Male sexual characters
(Fig.
Anterior telopods
(Fig.
Posterior telopods
(Fig.
Female sexual characters
(Fig.
(Figs
The live coloration of adults is generally dark green with two yellowish brown patches in the anterior half of tergites, this being quite unique for this species.
Almost 114 years since the original description, a redescription of Z. siamensis Hirst, 1907 has been made in this study based on the newly collected specimens from Koh Srichang (Srichang Island), here regarded as strict topotypes.
Considerable variation has been found in body size of the specimen described by
Zephronia lannaensis
Likhitrakarn & Golovatch, 2021 in
This species has been found to occur only in Chiang Mai Province. (Thailand, Chiang Mai Province, Doi Saket District, Huai Hong Khrai Royal Development Study Centre, 445 m a.s.l., 18°52'"N, 99°13'"E). All specimens were collected from dry dipterocarp forest (Likhitrakaen et al. 2021).
Based on specimens described by
Zephronia phrain
Likhitrakarn & Golovatch, 2021 in
Thailand – Tak Province • 2 ♂♂ 2 ♀♀; Mae Sot District, Phawor Shrine; 16°46'16.8"N, 98°41'13"E; 694 m a.s.l.; October 2016; S. Panha, R. Srisonchai, C. Sutcharit, W. Siriwut leg.
Body length : Length in male 29.0–31.0 mm (holotype 33.5 mm), female 30.0–33.0 mm; head 5.5 mm; thoracic shield 5.5–6.0 mm; anal shield 9.5–10.5 mm.
Body width : Width in male 16.5 mm (holotype 18.2 mm), female 16.5–17.0 mm; head 8.0–9.0 mm; thoracic shield 15.0–16.0 mm; anal shield 14.0–15.5 mm.
Body height : Height in male 10.0 mm (holotype 11.2 mm), female 10.0–11.0 mm; thoracic shield 9.0–10.5 mm; tergite 9.5–11.0 mm.
Color
(Fig.
Tergites
(Fig.
Legs
(Fig.
Subanal plate
(Fig.
Head, antenna, Tömösváry’s organ, gnathochilarium, stigmatic plates, laterotergites, collum, thoracic shield, endotergum, anal shield, male sexual characters, anterior telopods, posterior telopods, and female sexual characters: Same as the original description in
(Figs
Based on observations of live specimens in the field, two color patterns were found, dark green in type specimens and brown/dark brown in the others from Tak Province (Fig.
A species described by
Based on material described by
Zephronia viridisoma
Rosenmejer & Wesener, 2021 in
The type locality is in Thailand (Nakhon Si Thammarat Province, Sichon District, Khao Lark Waterfall, 9°03'"N, 99°47'"E). Khao Lark Waterfall = Khao Lak = near Si Khit Waterfall. The material was collected from a dense jungle in limestone areas (
Only nine specimens have been collected and all were found to appear in a small area. This species can be regarded as endemic to southern Thailand.
Holotype : Thailand – Khon Kaen Province • ♂; Tham Phaya Nakharat; 16°48'52"N, 101°57'16"E; 528 m a.s.l.; 21 July 2020; R. Srisonchai, C. Sutcharit leg.; CUMZ-Zeph0005. Paratypes: Thailand – Khon Kaen Province • 4 ♂♂ 3 ♀♀; same locality as holotype; CUMZ-Zeph0006 • 2 ♀♀; same Province, Chum Pae District, Tham Poo Lup; 16°49'45.4"N, 101°59'7.6"E; 346 m a.s.l.; 10 October 2014; R. Srisonchai, C. Sutcharit leg.; CUMZ-Zeph0006. Further specimens, not paratypes: Thailand – Loei Province • 1 ♂ 2 ♀♀; Wang Saphung District, Pak Puan Arboretum; 17°21'20"N, 101°44'59"E; 316 m a.s.l.; 10 October 2014; R. Srisonchai, C. Sutcharit leg.; CUMZ-Zeph0006.
This species is named after Henrik Enghoff from Natural History Museum of Denmark, University of Copenhagen, Denmark, the Danish myriapodologist who initiated an important research step on millipede studies for Thailand.
A member of Zephronia s. s. in which the position of Tömösváry’s organ located next to the aberrant ommatidia, not inside the antennal groove. Adult body length medium, > 29 mm, usually ca. 32 mm, up to 36 mm; body brown or dark brown, inner surface (underside) of anal shield with a single locking carina on each side, and leg-pair 2 of male coxa with a long membranous lobe at mesal margin. Similar in these respects to Z. golovatchi sp. nov., but differs from this species by the following combination of characters; antenna short, leg-pair 2 of female coxa apico-mesally with large and conspicuous coxal ridge, operculum of vulva regularly rounded and narrow in posterior view, mesal margin of operculum tapering apically, central margin (tip) of subanal plate shallowly concave, process of telopoditomere 2 of anterior telopod quite long and equal in length to the combination of telopoditomeres 3+4, and immovable finger telopoditomere 2 of posterior telopod (process of telopoditomere 2) equal in length to movable finger (consisting of telopoditomeres 3 and 4).
Body length : Length in male 29.0–33.0 mm (holotype 31.0 mm), female 30.0–36.0 mm; head 4.5–5.5 mm; thoracic shield 5.5–7.0 mm; anal shield 11.0–11.5 mm.
Body width : Width in male 16.0–18.5 mm (holotype 18.0 mm), female 16.0–19.0 mm; head 9.0–10.0 mm; thoracic shield 16.0–18.0 mm; anal shield 14.0–17.0 mm.
Body height : Height in male 10.0–12.0 mm (holotype 11.0 mm), female 10.0–13.0 mm; thoracic shield 10.0–12.0 mm; tergite 10.0–13.0 mm.
Color
(Fig.
Head : Wide and stout, subtrapeziform; anterior part of head with dense and long setae; central part of head glabrous; posterior part of head with dense and short setae. Labrum with a single tooth at anterior margin. Each eye with 90–100 ommatidia. Aberrant ocellus located near antennal groove (at upper part of groove).
Zephronia siamensis A–C male D, E female (CUMZ-Zeph0013) A right antenna, ventral view B the ninth left leg, posterior view C first coxae with stigmatic plates, posterior view D coxae of second legs with gonopores, posterior view E coxae and prefemur of second legs with vulvae, posterior view F subanal plate, ventral view. Abbreviations: cx = coxa, o = operculum, pre = prefemur, syn-cx = syncoxite, St-Pl = stigmatic plate.
Antenna
(Fig.
Zephronia siamensis A–C left anterior telopod, anterior, posterior and sublateral views, respectively D, E Left and right posterior telopods, posterior view F Posterior telopod, anterior view. Abbreviations: cr-T = crenulated teeth, cx = coxa, ML = membranous lobe, sp = sclerotized process, syn-cx = syncoxite.
Tömösváry’s organ : Separated from ommatidium, located on a brim between ommatidia and antennal socket, smaller in diameter than an individual ommatidium.
Gnathochilarium : Ventral surface with setae, other structures typical of the order. Mandibles not dissected.
Zephronia phrain A–D male specimen from Phawor Shrine, Tak Province E, F female A right antenna, ventral view B the ninth left leg, posterior view C first coxae with stigmatic plates, posterior view D coxae of second legs with gonopores, posterior view E coxae and prefemur of second legs with vulvae, posterior view F subanal plate, ventral view. Abbreviations: cx = coxa, o = operculum, pre = prefemur, syn-cx = syncoxite, st-pl = stigmatic plate.
Stigmatic plates
(Fig.
Zephronia phrain, male specimen from Phawor Shrine, Tak Province A telopods, anterior view B anterior telopod, anterior view C posterior telopod, posterior view D right anterior and posterior telopods, ventral view. Abbreviations: cr-T = crenulated teeth, cx = coxa, ML = membranous lobe, syn-cx = syncoxite.
Laterotergites : Laterotergite 1 narrow, projecting into a sharp tip. Laterotergite 2 larger than laterotergite 1, tip weakly extended, with a round projection.
Collum : Surface glabrous, except for anterior margins near rim with isolated and long setae.
Thoracic shield : Surface as those of tergites, covered with small setae, each seta located in a tiny pit; shallow groove wide anterolaterally, with very long setae.
Tergites
(Fig.
Endotergum
(Figs
Anal shield : Sexually dimorphic, in female very large and strongly rounded, in male slightly more rectangular. Outer surface covered by tiny and dense setae locating in small pits, similar to those of tergites. Inner surface (underside) covered by long setae; with a single, black, and long locking carina, half as long as length of last laterotergite.
Legs
(Fig.
Zephronia enghoffi sp. nov. A–D male holotype (CUMZ-Zeph0005) E, F female paratypes (CUMZ-Zeph0006) A right antenna, ventral view B the ninth left leg, posterior view C First coxae with stigmatic plates, posterior view D coxae of second legs with gonopores, posterior view E coxae and prefemur of second legs with vulvae, posterior view F subanal plate, ventral view. Abbreviations: cx = coxa, o = operculum, pre = prefemur, syn-cx = syncoxite, st-pl = stigmatic plate.
Subanal plate
(Fig.
Male sexual characters
(Fig.
Anterior telopods
(Fig.
Zephronia enghoffi sp. nov., male holotype (CUMZ-Zeph0005) A telopods, anterior view B anterior telopod, anterior view C posterior telopod, posterior view D right anterior and posterior telopods, ventral view. Abbreviations: cr-T = crenuations/teeth, cx = coxa, ML = membranous lobe, sp = sclerotized process, syn-cx = syncoxite.
Posterior telopods
(Fig.
Female sexual characters
(Fig.
(Figs
Remarks. With regard to the morphological characters of coxae 2 in both male and female, this species exhibits the remarkable shape in which the male has a very long membranous lobe (Fig.
Holotype : Thailand – Nakhon Ratchasima Province • ♂; Pak Chong District, Khao Yai National Park, Khao Luk Chang; 14°31'49.6"N, 101°21'32"E; 410 m a.s.l.; 26 April 2009; N. Likhitrakarn, C. Sutcharit, W. Siriwut leg.; CUMZ-Zeph0007. Paratypes: Thailand – Nakhon Ratchasima Province • 1 ♂ 4 ♀♀; same locality as holotype; CUMZ-Zeph0008.
The species is named for our highly esteemed colleague Sergei I. Golovatch (Zoological Museum, State University of Moscow, Russia), one of the most productive millipede taxonomists, who encouraged all new and young myriapodologists in Thailand.
Adult body length medium to large > 29 mm, usually 35 mm, up to 37 mm; body brown or dark brown, marginal bristles of endotergum extending over posterior margin, inner surface (underside) of anal shield with a single locking carina on each side, and leg-pair 2 of male coxa with membranous lobe at mesal margin. Similar in these respects to Z. enghoffi sp. nov., but differs from this species by the following combination of characters: antenna long; operculum of vulva regularly rounded and broad in posterior view; mesal margin of operculum not tapering apically; central margin (tip) of subanal plate divided by a conspicuous mesal constriction, process of telopoditomere 2 of anterior telopods shorter than telopoditomere 3; telopoditomere 3 of anterior telopods with 2 or 3 crenulated teeth; immovable finger telopoditomere 2 of posterior telopod (process of telopoditomere 2) shorter than movable finger (consisting of telopoditomeres 3 and 4).
Body length : Length in male 35.0–36.5 mm (holotype 35.0 mm), female 35.0–37.0 mm; head 5.5–7.5 mm; thoracic shield 5.0–6.0 mm; anal shield 10.5–11.5 mm.
Body width : Width in male 19.0–21.0 mm (holotype 20.0 mm), female 19.0–22.0 mm; head 10.0–11.0 mm; thoracic shield 17.5–20.5 mm; anal shield 16.0–18.5 mm.
Body height : Height in male ca 11.0 mm (holotype 11.0 mm), female 11.0–12.0 mm; thoracic shield 9.0–10.5 mm; tergite 10.0–11.5 mm.
Color
(Fig.
Head : Wide and stout, subtrapeziform; anterior part of head with dense and long setae; central part of head with sparse and long setae; posterior part of head with dense and short setae. Labrum with a single tooth at anterior margin. Each eye with ca. 90–100 ommatidia. Aberrant ocellus located inside antennal groove (at upper part of groove).
Antenna
(Fig.
Zephronia golovatchi sp. nov. A–D male holotype (CUMZ-Zeph0007) E, F female paratypes (CUMZ-Zeph0008) A right antenna, ventral view B the ninth left leg, posterior view C first coxae with stigmatic plates, posterior view D coxae of second legs with gonopores, posterior view E coxae and prefemur of second legs with vulvae, posterior view F subanal plate, ventral view. Abbreviations: cx = coxa, o = operculum, pre = prefemur, syn-cx = syncoxite, st-pl = stigmatic plate.
Tömösváry’s organ : Not distinctly separated from ommatidium, located closely to anterior margin of ommatidia, equal in size to an individual ommatidium.
Gnathochilarium : Ventral surface with setae, other structures typical of the order. Mandibles not dissected.
Stigmatic plates
(Fig.
Laterotergites : Laterotergite 1 narrow, projecting into a sharp tip. Laterotergite 2 broader than laterotergite 1, tip slightly extended, with round projection.
Collum : Surface glabrous, except for anterior margins near rim with isolated and long setae.
Thoracic shield : Surface as those of tergites, covered with inconspicuous and small setae, each seta located in tiny pits; shallow groove wide anterolaterally, with very long setae.
Tergites
(Fig.
Endotergum
(Figs
Anal shield : Sexually dimorphic, in female very large and weakly bell-shaped, in male slightly bell-shaped. Outer surface pubescent, similar to those of tergites; setae small and very short locating in tiny pits; anterior margin densely setose, posterior margin sparsely setose. Inner surface (underside) covered by setae; with a single, black, very long, locking carina, ca. 1/3 as long as length of last laterotergite.
Legs
(Fig.
Subanal plate
(Fig.
Male sexual characters
(Fig.
Anterior telopods
(Fig.
Zephronia golovatchi sp. nov., male holotype (CUMZ-Zeph0007) A telopods, anterior view B anterior telopod, anterior view C posterior telopod, posterior view D right anterior and posterior telopods, ventral view. Abbreviations: cr-T = crenulated teeth, cx = coxa, ML = membranous lobe, syn-cx = syncoxite.
Posterior telopods
(Fig.
Female sexual characters
(Fig.
(Fig.
This species has thin membranous lobe on male coxae 2 (Fig.
Holotype : Thailand • ♂; Phetchaburi Province, Tha Yang District, Wat Khao Khachiu; 12°57'42.7"N, 99°54'49.9"E; 22 m a.s.l.; 17 August 2019; R. Srisonchai, C. Sutcharit, W. Siriwut leg.; CUMZ-Zeph0009. Paratypes: Thailand – Phetchaburi Province • 8 ♂♂ 6 ♀♀; same locality as holotype; CUMZ-Zeph0010 • 1 ♂; same data as holotype; NHMD • 1 ♂; same data as holotype; ZMUM • 1 ♂; same data as holotype; ZRC. Further specimens, not paratypes: Thailand – Phetchaburi Province • 3 ♂♂ 2 ♀♀; Khao Yoi District, Wat Puangmali (Wat Tham Khao Ego); 13°18'45.3"N, 99°47'5.1"E; 22 m a.s.l.; 8 September 2016; R. Srisonchai, C. Sutcharit, W. Siriwut leg.; CUMZ-Zeph0010 • 1 ♂ 2 ♀♀; Rachaburi Province, Pak Tho District, Wat Buri Ratchawanaram; 13°22'45"N, 99°47'6"E, 26 m a.s.l.; 14 November 2019; R. Srisonchai, C. Sutcharit, W. Siriwut leg.; CUMZ-Zeph0010 • 2 ♂♂ 4 ♀♀; Kanchaburi Province, Mueang District, Wat Tham Mangkorn Thong; 13°59'8.2"N, 99°31'2.9"E; 46 m a.s.l.; 3 September 2017; R. Srisonchai, C. Sutcharit, W. Siriwut leg.; CUMZ-Zeph0010.
The species name recognizes the great professor and a long-time mentor to the authors, Somsak Panha (Chulalongkorn University Museum of Zoology, Thailand).
Differs from all congeners by the combination of the following characters; grey body color, adult body length ca. 21 mm, tergites covered by conspicuous setae, long setae on tergites extending over the posterior margin (Figs
Body length : Length in male 19.0–22.0 mm (holotype 20.0 mm), female 20.0–23.0 mm; head 4.0 mm; thoracic shield 4.0–4.5 mm; anal shield 6.0–7.5 mm.
Body width : Width in male 10.0–11.5 mm (holotype 10.0 mm), female 10.0–12.0 mm; head 6.0–7.0 mm; thoracic shield 10.0–11.0 mm; anal shield 9.5–10.5 mm.
Body height : Height in male 7.0–7.5 mm (holotype 7.0 mm), female 7.0–7.5 mm; thoracic shield 6.0–7.0 mm; tergite 6.5–7.5 mm.
Color
(Fig.
Head : Wide and stout, subtrapeziform; anterior part of head with dense and long setae; central part of head with sparse and long setae; posterior part of head with dense and short setae. Labrum with a single tooth at anterior margin. Each eye with ca. 70 ommatidia. Aberrant ocellus located near antennal groove (at upper part of groove).
Antenna
(Fig.
Zephronia panhai sp. nov. A–D male holotype (CUMZ-Zeph0009) E, F female paratypes (CUMZ-Zeph0010) A right antenna, ventral view B the ninth left leg, posterior view C first coxae with stigmatic plates, posterior view D coxae of second legs with gonopores, posterior view E coxae and prefemur of second legs with vulvae, posterior view F subanal plate, ventral view. Abbreviations: cx = coxa, o = operculum, pre = prefemur, syn-cx = syncoxite, st-pl = stigmatic plate.
Tömösváry’s organ : Separated from ommatidia, located on a brim between ommatidia and antennal socket, smaller in diameter than an individual ocellus.
Gnathochilarium : Ventral surface with setae, other structures typical of the order. Mandibles not dissected.
Stigmatic plates
(Fig.
Laterotergites : Laterotergites 1 and 2 narrow, projecting to a sharp tip.
Collum : Surface with very long setae in both anterior and posterior margins, setae located in pits.
Thoracic shield : Surface as those of tergites, covered with tiny setae; shallow groove with long setae, slightly broad at anterolateral margin.
Tergites
(Fig.
Endotergum
(Figs
Anal shield : Sexually dimorphic, in female weakly bell-shaped, in male strongly bell-shaped. Outer surface pubescent, setae small and very short, similar to those of tergites. Inner surface (underside) covered by setae; with a single locking carina, half as long as length of last laterotergite.
Legs
(Fig.
Subanal plate
(Fig.
Male sexual characters
(Fig.
Anterior telopods (Fig.
. Zephronia panhai sp. nov., male holotype (CUMZ-Zeph0009) A telopods, anterior view B anterior telopod, anterior view C posterior telopod, posterior view D right anterior and posterior telopods, ventral view. Abbreviations: cr-T = crenulated teeth, cx = coxa, ML = membranous lobe, sp = sclerotized process, syn-cx = syncoxite.
Posterior telopods
(Fig.
Female sexual characters
(Fig.
(Fig.
At the field collecting site, grey living specimens blended in perfectly with the brownish grey rock or leaf litter, making it difficult to find the animals. All specimens were infested by tiny, engorged, white, phoretic deutonymphs of an unidentified mite. The mite can often be found especially on the ventral part of the body such as antennal sockets and coxae, and could easily be discerned. The distribution of Z. viridescens from Dawei, Myanmar (Tavoy, Lower Burma – Moti Ram), is quite close to where the new species is distributed. However, Z. panhai sp. nov. differs from it by having a shorter body length ca. 21 mm (vs. longer, ca. 32 mm) and telopoditomeres 3 and 4 of anterior telopod distinctly separated (vs. indistinctly separated).
Zephronia viridescens
Attems, 1936: 180;
Zephronia cf. viridescens
–
Originally, this species was reported from Tavoy, Lower Burma (Moti Ram) by
Although ecological studies by
1 | Entire body grey (Fig. |
Z. panhai sp. nov. |
– | Body brown or green or partly green (not grey) (Figs |
2 |
2 | Second coxa in male with conspicuous membranous lobe (Figs |
3 |
– | Second coxa in male without membranous lobe, inconspicuous (Figs |
4 |
3 | Female vulval operculum regularly rounded, narrow in posterior view (Fig. |
Z. enghoffi sp. nov. |
– | Female vulval operculum regularly rounded, margin straight and wide (Fig. |
Z. golovatchi sp. nov. |
4 | Process of telopoditomere 2 of anterior telopod long, almost equal in length to the combination of telopoditomeres 3 and 4 (Fig. |
Z. phrain Likhitrakarn & Golovatch, 2021 |
– | Process of telopoditomere 2 of anterior telopod short, subequal in length to telopoditomere 3 (Fig. |
5 |
5 | Surface of tergites glabrous. Endoterga: tip of the longest bristles extended beyond posterior margin or extending over posterior margin. Female vulva with a large and pointed operculum, conspicuously protruded | Z. viridisoma Rosenmejer & Wesener, 2021 |
– | Surface of tergites with setae or hairy (Fig. |
6 |
6 | Body green or partly green (Fig. |
Z. siamensis Hirst, 1907 |
– | Entire body brown. Tergites without color patch on middle part of anterior half, all brown. Endoterga: posterior margin flat; middle section without a row cuticular impressions, inconspicuous | Z. lannaensis Likhitrakarn & Golovatch, 2021 |
The exploration of the millipede fauna in Thailand has uncovered a hitherto unknown diversity among the genus Zephronia. With the three new species described herein, the Thai giant pill-millipede genus Zephronia currently contains seven species that promote the number in the genus to 47 species in total. Considering the recorded species of Zephronia in Thailand, all can be found in small distribution area, although two of them (Z. panhai sp. nov. and Z. siamensis) have been shown to have somewhat wider ranges. However, they still occupy less than approximately 300 km2 along the mountain ranges in the North and also gulf of Thailand in the East (Fig.
SEM of endoterga of body ring 7, all from ventral views A, B Zephronia siamensis Hirst, 1907 C, D Zephronia enghoffi sp. nov. E, F Zephronia golovatchi sp. nov. G, H Zephronia panhai sp. nov. Abbreviations: cp = cuticular impression, ms = middle section, is = inner section, os = outer section, pm = posterior margin.
Known distribution of Zephronia spp. in Thailand. Red triangle = Zephronia lannaensis; green circle = Zephronia phrain; blue triangle = Zephronia enghoffi sp. nov.; sky blue square = Zephronia golovatchi sp. nov.; purple circle = Zephronia panhai sp. nov.; yellow diamond = Zephronia siamensis Hirst, 1907; orange square = Zephronia viridisoma.
The species boundaries of Zephronia have been mostly based on several morphological features (
As the two recognized groups of Zephronia have been proposed based on the location of Tömösváry’s organ (
The preceding records of the genus, without regarding the three newly described species, were recorded only from northern and eastern parts of Thailand. The central and southern areas of Thailand, which are the intermediate zone between the Malay Peninsula and the upper region of mainland Southeast Asia, had no records of the genus so far. Our finding of these three species fills the gaps in the distribution and confirms the genus Zephronia across Thailand. Further collecting in unexplored areas in several parts of mainland Southeast Asia, especially Cambodia, Laos, and Thailand, will probably reveal many new, remarkable species.
The authors would like to thank the National Park Departments, the Plant Genetic Conservation Project under the Initiative of Her Royal Highness Maha Chakri Sirindhorn and Center of Excellence on Biodiversity for the permission and enable us for the field trips in several restricted/remote areas. This research project was financially supported by the young researcher development project of Khon Kaen University and the Academic Affairs Promotion Fund, Faculty of Science, Khon Kean University, Fiscal year 2021 (RAAPF) for RS, and also partially supported by the TRF Strategic Basic Research BDG 6080011 (2017–2019) to CS and NL. We also thank the members of the Animal Systematics Research Unit for kind help in the field collecting. Special thanks go to Ting Hui Ng (ZRC) for English revision. The very useful comments that beneficially improved the manuscript from the referees are gratefully acknowledged.