Review Article |
Corresponding author: Sergei I. Golovatch ( sgolovatch@yandex.ru ) Corresponding author: Somsak Panha ( somsak.pan@chula.ac.th ) Academic editor: Pavel Stoev
© 2018 Natdanai Likhitrakarn, Sergei I. Golovatch, Ruttapon Srisonchai, Franck Brehier, Aung Lin, Chirasak Sutcharit, Somsak Panha.
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:
Likhitrakarn N, Golovatch SI, Srisonchai R, Brehier F, Lin A, Sutcharit C, Panha S (2018) Two new species of the millipede family Cambalopsidae from Myanmar (Diplopoda, Spirostreptida). ZooKeys 760: 55-71. https://doi.org/10.3897/zookeys.760.24837
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Two new species of cave-dwelling millipedes are described from Myanmar, one each in the genera Plusioglyphiulus Silvestri, 1923 and Trachyjulus Peters, 1864. Plusioglyphiulus digitiformis sp. n. joins the small peculiar group of congeners from Thailand which is characterized by such plesiomorphies as the tergal crests on the collum and following metaterga being transversely divided into two, not three parts, as in species of the genus Glyphiulus Gervais, 1847. However, this new species differs by the 3-segmented telopodites of ♂ legs 1, the anterior gonopodal coxosternum showing higher and nearly straight apicomesal processes and very evident apicolateral teeth, as well as the higher and acuminate paramedian coxal processes of the posterior gonopods, the latter’s telopodites demonstrating an apical fovea bearing a group of microsetae at the bottom. Trachyjulus bifidus sp. n. is primarily distinguished by the telopodites of their anterior gonopods being strikingly and deeply bifid. A key to the five species of Cambalopsidae currently known to occur in Myanmar is presented, and a map showing their distributions given.
diplopod, key, map, Myanmar, new species, Plusioglyphiulus , Trachyjulus
Myanmar is globally recognized as a highly important hotspot of biodiversity, supporting a great number of species and abundant forest resources (
Cambalopsidae is the largest family in the suborder Cambalidea, order Spirostreptida, and it currently contains > 100 species in 7–8 genera, all in Southeast Asia and Indo-Australia, up to central China in the north and Borneo in the east (
After more than 120 years of complete inactivity in this respect, the present paper puts on record another two new species of Cambalopsidae from Myanmar. It also provides a key to all five species of this family in that country, as well as a map showing their distributions. The two new species described below are also the first to come from caves in Myanmar.
The material was collected in Myanmar in 2015–2016 by Somsak Panha and members of the Animal Systematics Research Unit, Chulalongkorn University, as well as by a French collecting team headed by Louis Deharveng, of the Muséum National d’Histoire Naturelle, Paris, France. Photographs of live animals were taken in the laboratory using a Nikon 700D digital camera with a Nikon AF-S VR 105 mm macro lens. Specimens were preserved in 75% ethanol, and morphological observations made under an Olympus SZX7 stereo microscope.
Scanning electron micrographs (SEM) were taken applying a JEOL, JSM-5410 LV microscope, and the material returned to alcohol upon examination. Pictures of the gonopods of the holotypes were taken in the laboratory and assembled using “CellD” automontage software of the Olympus Soft Imaging Solution package. The key below is primarily based on the descriptions by
The collecting sites were located by GPS using the WGS84 datum.
The carinotaxic formulae in the descriptions follow those in
♂ (
7 ♂, 18 ♀ (
4 ♂, 14 ♀ (
To emphasize the finger-shaped apicomesal coxoternal processes (acp) of the anterior gonopodal coxosternum; adjective.
This new species is apparently most similar to P. antiquior Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2011, from a cave in Kanchanaburi Province, Thailand (
Length of holotype ca. 18 mm; adult paratypes 12–27 (♂) or 13–29 mm (♀); midbody segments circular in cross-section (Fig.
Colouration of live animals light red-brown (Fig.
Adult body with 46p+3a+T (holotype); paratypes with 37–60p+1–4a+T (♂) or 36–66p+1–4a+T (♀). Eye patches transversely ovoid, with 3+(1–2) blackish, rather flat ommatidia in 1–2 longitudinal rows. Antennae short and clavate (Figs
In width, collum = midbody rings (close to 13th to 15th) > head = ring 4 > 10 > 9 > 8 > 7 > 6 > 4 = 5 > 2 > 3; body abruptly tapering towards telson on a few posteriormost rings (Fig.
Plusioglyphiulus digitiformis sp. n., A–C, F, H–J, L, M ♀ paratype from Parpant area D, E, G, K, N–P ♂ paratype from Parpant area. A, B anterior part of body, lateral and dorsal views, respectively C collum and body ring 2, dorsal view D head, ventral view E anterior part of antenna, lateral view F second body crest, dorsal view G bacilliform sensilla on antennomere 5, lateral view H, I midbody rings, lateral and dorsal views, respectively J porostele, lateral view K cross-section of a midbody segment L midbody crests, dorsal view M midbody prozona, dorsal view N–P posterior part of body, lateral, dorsal and ventral views, respectively.
Collum with 6+6 longitudinal crests starting from anterior edge, carinotaxic formula of collum, 1+2p+3+4p/t+5p/t+pp+/ma (Fig.
Following metaterga similarly strongly crested (Figs
Tegument delicately alveolate-areolate (Fig.
Limbus extremely finely and more or less regularly denticulate.
Epiproct (Fig.
Ventral flaps behind gonopod aperture on ♂ segment 7 barely distinguishable as low swellings, forming no marked transverse ridge.
Legs nearly as long as body diameter (Fig.
♂ legs 1 with an unusually short, central hook and relatively strongly reduced, 3-segmented telopodites (Figs
Plusioglyphiulus digitiformis sp. n., ♂ paratype from Parpant area. A, B ♂ legs 1, caudal and anterior views, respectively C claw of ♂ leg 1, anterior view D ♂ legs 2, caudal view E, F ♂ legs 3, anterior and caudal views, respectively G, H anterior gonopods, anterior and caudal views, respectively I microsetae on top of coxal processes of anterior gonopods, caudal view K, L posterior gonopods, caudal and anterior views, respectively J tip of telopodite of posterior gonopod, caudal view M setose lobe on telopodite of posterior gonopod, anterior view.
♂ legs 2 clearly enlarged, with high and large coxae; telopodites hirsute on anterior face; penes broad, oblong-subtrapeziform, fused at base, each with 3–4 strong setae distolaterally (Figs
♂ legs 3 modified in having coxae especially slender and elongate, but with somewhat shortened telopodites (Figs
Anterior gonopods (Figs
Posterior gonopods (Figs
Plusioglyphiulus digitiformis sp. n., A, B ♂ paratype from Mondawa Gu Cave C–H ♂ paratype from Parpent Cave n°2. A antenna, lateral view B gnathochilarium, ventral view C legs 1, anterior view D legs 2, caudal view E legs 3, caudal view F midbody leg, anterior view G anterior gonopods, caudal view H, I posterior gonopods, caudal and anterior views, respectively. Abbreviations: acp apiconmesal coxoternal process bcp basolateral coxosternal process te telopodites ap anterior coxal processes cp caual coxal processes pp paramedian coxal processes. Scale bars: 0.2 mm.
The genus Plusioglyphiulus Silvestri, 1923 has recently been reviewed (
Most species of this genus show particularly enlarged colla with the tergal crests both on the collum and following segments being clearly divided transversely into three parts. Only two species, P. antiquior and P. panhai Golovatch, Geoffroy, Mauriès & VandenSpiegel, 2011, both from caves in Thailand and both found quite close to the frontier to Myanmar, are remarkable in still showing the pattern of carinotaxy observed in the genus Glyphiulus Gervais, 1847 (
In particular, while their gonopods are relatively complex and unequivocally the same as in typical Plusioglyphiulus, the carinotaxic pattern is simple and typical of Glyphiulus, i.e., the crests on their colla and following metaterga are divided transversely into two, not three, parts. In this respect, P. digitiformis sp. n. clearly joins the above duet, showing the closest similarities, both morphologically and geographically, to P. antiquior.
Non-type material shows all characters of the type series, but their localities lie very far from the others (ca. 470 km) (Fig.
Interestingly, the famous Burmese amber, 99–100 Mya, appears to contain a typical Plusioglyphiulus yet to be described (Wesener in litt.). This is evidence both of the very old age of this genus and its long presence in situ.
♂ (
3 ♂, 1 ♀, 3 juv. (
To emphasize the strongly bifid telopodites of the anterior gonopods; adjective.
Differs from other Trachyjulus species based primarily on the following combination characters: the strongly elongated and bifid telopodites (te) of the anterior gonopods, coupled with the absence of flagella and the presence of deeply bipartite posterior gonopods, in which the telopodites (te) are much shorter than the massive, paramedian, coxal processes (cp).
Length of holotype ca. 19 mm; adult paratypes 13–30 (♂) or 12–25 mm (♀); midbody segments circular in cross-section (Fig.
Trachyjulus bifidus sp. n., A–C ♀ paratype from Linno Gu n°1 Cave D–U ♂ paratype from Linno Gu n°1 Cave. A, B anterior part of body, lateral and dorsal views, respectively C collum and body ring 2, dorsal view D, E head, anterior and ventral views F anterior part of antenna, ventral view G bacilliform sensilla on antennomere 5, lateral view H tip of antenna I base of antennomere 5, lateral view J, K, O midbody rings, lateral, dorsal and ventral views, respectively L midbody ring, dorsal view M midbody prozona, dorsal view N cross-section of a midbody ring P claws of midbody legs Q midbody porostele, dorsal view R–U, posterior part of body, lateral, dorsal and ventral views, respectively.
Coloration of adults in alcohol light grey-brown to dark castaneous brown, without a clear-cut pattern. Head, antennae and venter light yellowish to brownish. Ommatidia brown to blackish.
Adult body with 45p+4a+T (holotype); paratypes with 39–70p+2–4a +T (♂) or 40–60p+2–6a+T (♀). Eye patches transversely ovoid, with 3(4)+3(1) blackish, rather flat ommatidia in 1–2 longitudinal rows. Antennae short and clavate (Figs
In width, collum = midbody rings (close to 6th to 8th) > head = ring 2 > 8–10 > 7 > 6 > 5 > 3 = 4; body abruptly tapering towards telson on a few posteriormost rings (Fig.
Collum (Fig.
Tegument smooth (Fig.
Epiproct (Fig.
Ventral flaps behind gonopod aperture on ♂ segment 7 evident swellings, forming a marked transverse ridge.
Legs nearly as long as body diameter (Fig.
♂ legs 1 highly characteristic (Figs
Trachyjulus bifidus sp. n., ♂ paratype from Linno Gu n°1 Cave. A, B legs 1, anterior and caudal views, respectively C leg 2, caudal view D penes, caudal view E legs 3, caudal view F, G anterior gonopods, anterior and caudal views, respectively H tip of telopodite of anterior gonopod, caudal view I, J posterior gonopods, anterior and caudal views, respectively K right posterior gonopod, caudal view.
Trachyjulus bifidus sp. n., ♂ holotype from San Gu Cave. A antenna, lateral view B gnathochilarium, ventral view C legs 1, anterior view D legs 2, caudal view E legs 3, caudal view F posterior gonopods, caudal view G H anterior gonopods, anterior and caudal views, respectively. Abbreviations: cp coxal processes te telopodites acp anterior coxosternal process pcp posterior coxoternal process. Scale bars: 0.2 mm.
Distribution of two new cambalopsid species. Key: □ Plusioglyphiulus digitiformis sp. n., Jatwet Gu and Kyauk Khaung Cave ■ Plusioglyphiulus digitiformis sp. n., Mondawa Gu Cave △ Plusioglyphiulus digitiformis sp. n., Cave in Parpant area ● Plusioglyphiulus digitiformis sp. n., Parpent Cave n°1 and Parpent Cave n°2 ◊ Plusioglyphiulus digitiformis sp. n., Saddan Sin Gu Cave and Nathack Gu Cave ○ Trachyjulus bifidus sp. n., San Gu Cave, Yae Gu Cave, Linno Gu n°1 Cave and Thin Bow Gu Cave.
♂ legs 2 slightly reduced, but coxa and femur hypertrophied (Figs
♂ legs 3 slightly reduced, modified in having coxae especially slender and elongate (Figs
Anterior gonopods (Figs
Posterior gonopods (Figs
The genus Trachyjulus Peters, 1864 is currently known to comprise 31 species ranging from Nepal, India, and Sri Lanka in the west, through Bangladesh and Myanmar to Vietnam, Thailand, Malay Peninsula, Singapore, and Indonesia (Sumatra and Java) in the east (
Based on the pigmented body and eye patches, and like most if not all other cave-dwelling congeners known to date, T. bifidus sp. n. seems to be hardly more than a troglophile.
No special key to relevant genera involved seems to be needed, as the one given below to Myanmar species contains the necessary information.
1 | Collum smooth, without strong longitudinal crests (Fig. |
2 |
– | Collum with strong longitudinal crests (Fig. |
3 |
2 | Each telopodite (te) of anterior gonopods with a small birdhead-shaped process at tip, coxosternal process slender and undivided | Trachyjulus calvus (Pocock, 1893) |
– | Telopodites (te) of anterior gonopods divided into two strongly curved finger-shaped processes (Figs |
Trachyjulus bifidus sp. n. |
3 | ♂ legs 1 with 3-segmented telopodites (Figs |
Plusioglyphiulus digitiformis sp. n. |
– | ♂ legs 1 with 5-segmented telopodites | 4 |
4 | Carinotaxy of collum: anterior transverse and posterior transverse rows consisting of 10 and 9 crests, respectively | Podoglyphiulus doriae (Pocock, 1893) |
– | Carinotaxy of collum: anterior transverse and posterior transverse rows consisting of 6 and 5 crests, respectively | Podoglyphiulus feae (Pocock, 1893) |
There are 94 millipede species currently known to occur in Myanmar, including both new ones described above. The new material comes from some of the 27 caves located within a radius of ca. 70 km around the town of Kalaw, Shan State, northeastern Myanmar (
This project was partly funded through grants received from the Office of the Royal Development Projects Board (RDPB), while most of the financial support was obtained from TRF Strategic Basic Research BDG 6080011 (2017–2019) to CS and NL, and TRF Senior Research Scholar RTA 5880002 (2015–2018) and BDC-PG2-160012 to SP. We thank the members of the Animal Systematics Research Unit for their invaluable assistance in the field.
We are most grateful to all reviewers who have provided constructive criticism and thus considerably improved our paper.