Research Article |
Corresponding author: Duc-Anh Nguyen ( ducanh410@yahoo.com ) Academic editor: Robert Mesibov
© 2016 Duc-Anh Nguyen, Kuem-Hee Jang, Ui-Wook Hwang.
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:
Nguyen AD, Jang K-H, Hwang U-W (2016) The first record of the millipede genus Streptogonopus Attems, 1914 from Vietnam, with description of a new species (Diplopoda, Polydesmida, Paradoxosomatidae). ZooKeys 601: 111-118. https://doi.org/10.3897/zookeys.601.9165
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This paper describes a new species of the millipede genus Streptogonopus Attems, 1914, S. montanus sp. n. from Vietnam, the first record of Streptogonopus in Vietnam. The new species is characterised by the solenophore completely sheathing the solenomere, both coiled twice, and the solenophore with a small spine at its middle. The species was found at ca. 1,800–2,100 m on Ngoc Linh Mountain. This first record for the genus in the Indochina peninsula has expanded its distributional range to the easternmost part of Southeast Asian mainland. An identification key to Streptogonopus species is also provided.
Millipede, Paradoxosomatidae , first record, new species, Vietnam
The genus Streptogonopus Attems, 1914 was created for three species, Strongylosoma contortipes Attems, 1898, Strongylosoma jerdani Pocock, 1892 and Strongylosoma phipsoni Pocock, 1892 (
Currently, the genus Streptogonopus Attems, 1914 comprises only five valid species: S. neglectus from Eritrea; S. phipsoni from India, Pakistan, Bangladesh and Nepal; S. jerdani, S. nitens, both from India; S. degerboelae, from Thailand. This work provides the first record of the genus in Vietnam with the description of a new species.
Material examined was collected from the Ngoc Linh Mountain, the second highest mountain in Vietnam (ca. 2,600 m a.s.l.). All material was preserved in ethanol 80% and is housed in the Institute of Ecology and Biological Resources (IEBR), Vietnam Academy of Science and Technology, Hanoi, Vietnam.
Gonopods were removed for morphological examination. Only the left gonopod of holotype was coated with gold for scanning electron microscopy (SEM) using an ABT 32 scanning electron microscope. Line drawings were made using an Olympus microscope SZX10. Digital images were taken using a camera Infinity3 Lumenera attached to a Leica M205C stereomicroscope and stacked using the software I-Solutions.
Streptogonopus
Attems, 1914: 219;
Strongylosoma contortipes Attems, 1898, by original designation.
The genus can be separated into two small groups based on the absence or presence of paraterga. The former group contains S. jerdani and S. degerboelae, the latter comprises S. neglectus, S. phipsoni, and S. nitens.
Holotype: 1 male (IEBR-Myr 131H) Vietnam, Kon Tum Prov., Ngoc Linh Mts. (107°58'30"E; 15°04'09"N), primary forest, 1,900 m a.s.l., pitfall traps, 29 March – 4 April 2006, leg. Nguyen A.D.
Paratypes: 1 female (IEBR-Myr 131P) same data as holotype; 1 male (IEBR-Myr 145) same locality, but 1,900–2,100 m a.s.l., 21 March–9 April 2006; 2 males, 1 juvenile (IEBR-Myr 132) same locality, but 1,800 m a.s.l., pitfall traps, 20–26 March 2006, all leg. Nguyen A.D.
This species is recognised by the gonopod femorite grooved mesally, slightly curved and expanded distally, without processes; solenophore and solenomere coiled twice, equal in length. Solenophore with a small spine at ½ its length.
“montanus”, an adjective to emphasise that the species has been found in a mountainous region.
Length 26.7–28.2 mm (male) and 30 mm (female). Width of midbody pro- and metazonae 2.3–2.5 mm (male), 2.8 mm (female) and 2.7–2.9 mm (male), 3.1 mm (female), respectively.
Coloration (Fig.
Streptogonopus montanus sp. n., holotype; anterior segments, lateral view (A), dorsal view (B), ventral view (C); posterior segments, dorsal view (D), ventral view (E); telson, ventral view (F); sternal processes between coxae of legpair 4, subventral view (G). Scale bar = 1 mm. For abbreviations see text.
Head subequal to collum in width; clypeolabrum modestly setose. Epicranial suture distinct. Antennae slender and long, reaching the end of segment 4 when stretched posteriorly. Antennomere 2=3=4=5=6>1>7 in length.
Collum (Fig.
In width, segment 3<4<2=5–16, thereafter gradually tapering towards telson (Figs
Paraterga (pa) (Fig.
Epiproct (ep) (Fig.
Sterna (Figs
Legs (Figs
Gonopods relatively simple (Figs
This new species could be assigned to the second group characterised by modestly developed paraterga. However, it differs from three its congeners, S. neglectus, S. phipsoni, and S. nitens in solenomere and solenophore being equal in length and strongly coiled twice and the solenophore having a small spine at its middle.
(based on the keys compiled by
1 | Paraterga strongly reduced, even totally missing | 2 |
– | Paraterga poorly to modestly developed | 3 |
2 | Body coloration yellowish. Body surface wrinkled and dull. India | S. jerdani |
– | Body coloration marble brown. Body surface smooth and somewhat shining. Thailand | S. degerboelae |
3 | Midbody width large, more than 2 mm. Asia | 4 |
– | Midbody width small, less than 2 mm. Africa (Eritrea) | S. neglectus |
4 | Solenophore and solenomere strongly coiled twice; solenophore with a small spine at its middle. Vietnam | S. montanus sp. n. |
– | Solenophore and solenomere not coiled twice; solenophore without a small spine at its middle. South Asia | 5 |
5 | Pleurosternal carinae caudally sharp and dentiform | S. phipsoni |
– | Pleurosternal carinae caudally rounded and lobiform | S. nitens |
The genus is known to occur in Eritrea, India, Pakistan, Bangladesh, Nepal and Thailand (
The new species was found at a high elevation (ca. 1,800–2,100 m a.s.l.) on Ngoc Linh Mountain (Kon Tum Province), the second highest mountain, in Vietnam and is thus unlikely to be an introduction due to human activities. The relatively few records for the genus indicates that there are likely to be more Streptogonopus species awaiting discovery in Indochina and its adjacent regions.
Being located in the Burmese-Indochinese Biodiversity Hotspot (
The first author thanks the Vietnamese-Russian Joint Tropical Center (Vietnam Ministry of Defense) for organizing the field surveys in Ngoc Linh Mountain, and Dr. Nicholas Porch (Deakin University, Australia) for kindly correcting and improving the English. This research is funded by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under grant number 106-NN.05-2015.22, and the National Research Foundation of Korea for the fellowship to Korea granted to A.D. Nguyen. Two reviewers are acknowledged for their invaluable comments which improved the paper.