Research Article |
Corresponding author: Somsak Panha ( somsak.pan@chula.ac.th ) Academic editor: Dragan Antić
© 2021 Natdanai Likhitrakarn, Sergei I. Golovatch, Ruttapon Srisonchai, 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, Panha S (2021) Two new species of the millipede genus Tylopus Jeekel, 1968 from Shan State, Myanmar (Diplopoda, Polydesmida, Paradoxosomatidae). ZooKeys 1040: 167-185. https://doi.org/10.3897/zookeys.1040.66209
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The predominantly Indochinese to southern Chinese millipede genus Tylopus presently comprises 76 described species, including two new, T. monticola sp. nov. and T. sutchariti sp. nov., both described and illustrated based on material from a limestone mountain in Taunggyi District, Shan State, Myanmar. Both new species have been found to occur syntopically near limestone caves and are assumed to be narrowly endemic to the Taunggyi Mountains, southwestern Shan State, Myanmar. A key to all six Tylopus species known to occur in Myanmar is provided, and their distributions are also mapped.
Key, map, Paradoxosomatinae, Sulciferini, taxonomy, Tylopus monticola sp. nov., Tylopus sutchariti sp. nov.
The predominantly Indochinese to southern Chinese millipede genus Tylopus Jeekel, 1968, has long been recognized as one of the most speciose and widespread not only within the family Paradoxosomatidae, but also in the entire class Diplopoda (
Myanmar forms part of the Indo-Burma biodiversity hotspot (
Four Tylopus species, all endemic, have been found in Myanmar. The first two species of Tylopus to be revealed from that country were Tylopus doriae (Pocock, 1895) and T. silvestris (Pocock, 1895), both described by
The present paper puts on record two new species of Tylopus collected from a limestone mountain in the Taunggyi District, southwestern Shan State, Myanmar. A key to and updated distributions of all six species of Tylopus currently known to occur in Myanmar are also provided.
New material was collected in Myanmar, especially in limestone mountain areas, with the support of Fauna & Flora International (FFI) in 2015–2017, collaborating with the Animal Systematics Research Unit (ASRU), Chulalongkorn University. The collecting activities took place under the limestone conservation projects which aim to protect biodiversity in limestone habitats (
Live animals were photographed 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 were carried out in the laboratory using an Olympus stereo microscope. Scanning electron micrographs (SEM) of gonopods coated with gold were taken using a JEOL, JSM–5410 LV microscope, returned to alcohol after SEM examination. Digital images of the specimens were taken in the laboratory and assembled using the “CellD” automontage software of the Olympus Soft Imaging Solution GmbH package. In addition, line drawings of gonopod characters were also prepared. Both holotypes, as well as most of the paratypes are housed in the Museum of Zoology, Chulalongkorn University (CUMZ), Bangkok, Thailand; some paratypes are donated to the collection of the Zoological Museum, State University of Moscow (ZMUM), Russia, as indicated in the text.
Collecting sites were located by GPS using the WGS84 datum. The distribution maps of all Tylopus species recorded from Myanmar were executed using QGIS 3.18.0 (
In the synonymy sections, D stands for the original description and/or subsequent descriptive notes, K for the appearance in a key, L for the appearance in a species list, and M for a mention.
Terminology concerning gonopodal and somatic structures mostly follows
Subfamily Paradoxosomatinae Daday, 1889
Tribe Sulciferini Attems, 1898
Tylopus brehieri Golovatch, VandenSpiegel & Semenyuk, 2016: 335 (D).
Shan State, Kyauk Khaung (= Stone Cave) (
Orthomorpha doriae Pocock, 1895: 823 (D).
Orthomorpha Doriae (sic!) – Attems, 1898: 339 (L, K).
Orthomorpha (Kalorthomorpha) doriae – Attems, 1936: 204 (L).
Orthomorpha (Orthomorpha) doriae – Attems, 1937: 80 (D, K).
Orthomorpha doriae – Weidner, 1960: 85 (L).
Agnesia doriae – Jeekel, 1965: 100 (D, K).
Tylopus doriae
– Jeekel, 1968: 60 (M);
Yado, 1000–1400 m; Bia-Po, 1000–1200 m, Meteleo, 900–1200; Puepoli, 900–1200 m (
Also found in Doi Suthep National Park (1400–1500 m), Chiang Mai Province, Thailand (
Tylopus punctus Likhitrakarn, Golovatch & Panha, 2016: 29 (D).
Mintaingbin Forest Camp, ca 35 km north of Aungban, Chan State, 20°55'20"N, 96°33'60"E, ca 1300 m a.s.l. (
Orthomorpha silvestris Pocock, 1895: 824 (D).
Orthomorpha silvestris – Attems, 1914: 238 (L); 1936: 205 (L); 1937: 94 (L).
Agnesia silvestris – Jeekel, 1965: 104 (D, K).
Tylopus silvestris
–
Village of Thao (Carin Ghecu, 1200–1400 m) (
Holotype: Myanmar – Shan State • ♂; Taunggyi District, near Montawa Cave; elev. 1204 m; 20°45'15.9"N, 97°01'03.4"E; 21 Sep. 2016; J. Sutcharit, R. Srisonchai leg.; CUMZ. Paratypes: Myanmar – Shan State • 3 ♀♀; same collection data as holotype; CUMZ • 1 ♀; same collection data as holotype; ZMUM • 3 ♀♀; near Aye Say Tee Cave; elev. 1583 m; 20°47'29.5"N, 97°03'01.6"E; 21 Sep. 2016; J. Sutcharit, R. Srisonchai leg.; CUMZ • 1 ♂; Parpant area, outside the cave; elev. 1159 m; 20°15'03.7"N, 97°14'23.9"E; 23 Sep. 2016; J. Sutcharit, R. Srisonchai leg.; CUMZ • 1 ♂; same collection data as previous; ZMUM.
Using the latest key to Tylopus species (
Length of holotype ca 30 mm; adult paratypes 29–31 (♂) or 32–35 mm (♀), width of midbody pro- and metazonae of holotype, 2.4 and 3.6 mm; adult paratypes 2.4–2.5 and 3.4–3.7 mm (♂) or 2.9–3.5 and 3.7–4.5 mm (♀), respectively.
Colouration of live animals dark brown (Fig.
Clypeolabral region and vertex sparsely setose, epicranial suture distinct. Antennae short (Figs
Tylopus monticola sp. nov., ♂ holotype (CUMZ) A, B anterior part of body, dorsal and lateral views, respectively C, D segments 10 and 11, dorsal and lateral views, respectively E–G posterior part of body, lateral, subdorsal and subventral views, respectively H, I sternal cones between coxae 4, subcaudal and sublateral views, respectively.
Tegument rather smooth and shining, prozonae very finely shagreened, metaterga mainly smooth, but often rugulose; surface below paraterga finely microgranulate (Fig.
Paraterga strongly developed (Fig.
Sterna densely setose, without modifications (Fig.
Gonopods (Figs
To emphasize the habitats where this new species was discovered; “monticola” meaning a mountain-dweller or a highlander; noun in apposition.
Tylopus monticola sp. nov., ♂ holotype (CUMZ) A, B left gonopod, mesal and lateral views, respectively C leg of segment 10. Abbreviations: g mesal groove/hollow of femorite, h short and stout process of femorite, l apicolateral lobe of femorite, z serrate process of femorite. Scale bars: 0.5 mm.
The species was found quite far away (about 120 air-km) from the type locality of the most similar species, T. rugosus Golovatch & Enghoff, 1993 (Fig.
Holotype: Myanmar – Shan State • ♂; Taunggyi District, near Montawa Cave; elev. 1204 m; 20°45'15.9"N, 97°01'03.4"E; 21 Sep. 2016; R. Srisonchai leg.; CUMZ. Paratype: Myanmar – Shan State • 1 ♀; same collection data as holotype; CUMZ.
This new species comes to a dead end in couplet 5 in the latest key to Tylopus species (
Tylopus sutchariti sp. nov., ♂ holotype (CUMZ) A, B anterior part of body, dorsal and lateral views, respectively C, D segments 10 and 11, dorsal and lateral views, respectively E–G posterior part of body, lateral, subdorsal and subventral views, respectively H, I sternal cones between coxae 4, subcaudal and sublateral views, respectively.
Length 24.1 (♂) or 22.5 mm (♀), width of midbody pro- and metazona 1.8 and 2.7 mm (♂) or 2.2 and 2.6 mm (♀), respectively.
Colouration of live animals dark brown (Fig.
Clypeolabral region and vertex sparsely setose, epicranial suture distinct. Antennae short (Figs
Tegument rather smooth and shining, prozonae very finely shagreened, metaterga smooth and finely rugulose; surface below paraterga finely microgranulate (Fig.
Paraterga strongly developed (Fig.
Sterna densely setose, without modifications (Fig.
Gonopods (Figs
To honour Dr. Chirasak Sutcharit, Professor at the Department of Biology of the Chulalongkorn University, Bangkok, who participated in collecting the type series.
Tylopus sutchariti sp. nov., ♂ holotype (CUMZ) A, B left gonopod, mesal and lateral views, respectively C leg of segment 10. Abbreviations: g mesal groove/hollow of femorite, h short and triangular process of femorite, l apicolateral lobe of femorite, m dorsoapical lobe of femorite, sl tip of solenomere, sph solenophore, z short and simple process of femorite. Scale bars: 0.5 mm.
Gonopod structure of Tylopus rugosus Golovatch & Enghoff, 1993, ♂ holotype, left gonopod A–C mesal, lateral and dorsal views, respectively. Abbreviations: h strong hook-shaped process of femorite, l apicolateral lobe of femorite, z serrate process of femorite. Scale bar: 0.5 mm (after
Both new species described here have been found to occur syntopically (Fig.
Distributions of Tylopus species recorded from Myanmar. Pink circle: T. brehieri Golovatch, VandenSpiegel & Semenyuk, 2016; Red Asterisk: T. punctus Likhitrakarn, Golovatch & Panha, 2016; Yellow inverted triangle: T. monticola sp. nov.; Blue square: T. sutchariti sp. nov. and T. monticola sp. nov.; Orange diamond: T. silvestris (Pocock, 1895); Green triangle: T. doriae (Pocock, 1895).
1 | All ♂ prefemora normal, not bulged laterally | 2 | |
– | Most ♂ prefemora clearly swollen laterally (Figs |
3 | |
2 | Body smaller: width up to 2.1–2.5 mm. Midbody paratergal corner very narrowly rounded and not protruding caudad past rear margin. Gonopod process h small and pointed | Tylopus punctus Likhitrakarn, Golovatch & Panha, 2016 | |
– | Body larger: width 3.0 mm. Midbody paratergal corner nearly pointed and protruding caudad past rear margin. Gonopod process h absent | T. silvestris (Pocock, 1895) | |
3 | Paratergal calluses with only one incision. Gonopod postfemoral lobe l much longer than broad; area basal to l delimited by a distinct cingulum (Figs |
4 | |
– | Paratergal calluses with two incisions. Gonopod postfemoral lobe l either as long as broad or longer; no cingulum basal to l (Figs |
5 | |
4 | Sternal lobe between ♂ coxae 4 deeply notched (Fig. |
T. sutchariti sp. nov. | |
– | Sternal lobe between ♂ coxae 4 prominent and subquadrate. Gonopod process h absent, while apicolateral lobe (l) subtriangular with an apically rugose and denticulate margin | T. brehieri Golovatch, VandenSpiegel & Semenyuk, 2016 | |
5 | Gonopod process z large and long, protruding beyond apicolateral lobe (l) (Figs |
T. monticola sp. nov. | |
– | Gonopod process z smaller and not protruding beyond apicolateral lobe (l) (Fig. |
T. rugosus Golovatch & Enghoff, 1993 |
Of a total of 76 species of Tylopus presently known globally, including two new described above, most of the diversity (31 species, or >41%) comes from Thailand, followed by Vietnam (21 species), Laos (12 species), southern China (8 species) and Myanmar (6 species). Almost all Tylopus species appear to be confined to montane woodlands exceeding 500 m in elevation (
The genus Tylopus seems to be particularly similar to two genera of the large and mostly Asian tribe Sulciferini, viz. Oxidus Cook, 1911 and Hedinomorpha Verhoeff, 1934. All three share the presence of a unique gonopodal apicolateral lobe (l) separated from the femorite by a more or less distinct, basal, (sub)transverse sulcus.
In addition to putting on record two new, presumably narrowly endemic species of Tylopus from the Taunggyi Mountains, southwestern Shan State, Myanmar, and thus bringing the number of Tylopus spp. of Myanmar to a total of six, we map their distributions (Fig.
This project was funded through grants received from TRF Strategic Basic Research BDG 6080011 (2017–2019) to CS and NL, and Center of Excellence on Biodiversity (BDC-PG4-163008) to SP. We thank the members of the Animal Systematics Research Unit for their invaluable assistance in the field. One of us (SIG) was partly supported by the Presidium of the Russian Academy of Sciences, Program No. 41 “Biodiversity of Natural Systems and Biological Resources of Russia”. We are most grateful to Henrik Enghoff (Denmark), Piyatida Pimvichai (Thailand) and Dragan Antić (Serbia), the reviewers who have provided constructive criticism and thus considerably improved our paper.