Research Article |
Corresponding author: Piyatida Pimvichai ( piyatida_pimvichai@yahoo.com ) Academic editor: Pavel Stoev
© 2022 Piyatida Pimvichai, Henrik Enghoff, Thierry Backeljau.
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:
Pimvichai P, Enghoff H, Backeljau T (2022) Redescription of the giant Southeast Asian millipede Spirobolus macrurus Pocock, 1893 and its assignment to the new genus Macrurobolus gen. nov. (Diplopoda, Spirobolida, Pachybolidae). ZooKeys 1087: 1-18. https://doi.org/10.3897/zookeys.1087.71280
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A new genus of the millipede family Pachybolidae from Southeast Asia is described: Macrurobolus gen. nov., with Spirobolus macrurus Pocock, 1893 as type species. This latter species is DNA barcoded (COI) and redescribed based on male morphological characters, which hitherto were unknown. The new genus differs from other pachybolid genera by having (1) the preanal ring process long and protruding beyond the anal valves and (2) the anterior gonopod telopodite distally abruptly narrowed, forming an extremely long, slender, elevated process curved caudad. Given that Macrurobolus gen. nov. is a monotypic genus, it is aphyletic and thus requires further taxonomic revision.
Aphyly, Myanmar, taxonomy, Thailand
Spirobolus macrurus Pocock, 1893 is, with its length of up to 110 mm and diameter of up to 10 mm, the largest pachybolid millipede in SE Asia, but despite its large size, the species is still poorly known. Its original description was based on a single female specimen from Kawkareet, Tenasserim, Myanmar, and did not include the genital parts. Yet,
In the present paper we redescribe and barcode Spirobolus macrurus based on an old male specimen discovered in the collections of the Natural History Museum of Denmark, Copenhagen, and new live material, including an adult male specimen, collected during recent fieldwork in Thailand. As a result we also create the new genus Macrurobolous gen. nov. to accommodate Spirobolus macrurus, so that this species will be referred to as Macrurobolus macrurus comb. nov.
Live specimens were hand collected and preserved in 70% ethanol for morphological study or placed in a freezer at –20 °C for DNA analysis. Specimens were also examined from the following collections:
This research was conducted under the approval of the Animal Care and Use regulations (numbers U1-07304-2560 and IACUC-MSU-037/2019) of the Thai government.
Gonopods were photographed with a digital camera manipulated via the program Helicon Remote (v. 3.1.1.w). The Zerene Stacker Pro software was used for image-stacking. Drawings were made using a stereomicroscope. Samples for scanning electron microscopy (SEM) were air-dried directly from alcohol and sputter-coated for 250 s with gold. SEM micrographs were taken with an environmental scanning electron microscope (ESEM)-FEI Quanta 200. Voucher specimens were deposited in the collections of
Total genomic DNA was extracted from legs of a male specimen of Macrurobolus macrurus, comb. nov. from Wat Tham Inthanin, Mae Sot District, Tak Province, Thailand (
Specimens from which the COI gene fragment was sequenced.
Voucher code | Locality | COI | |
---|---|---|---|
Genus Apeuthes | |||
A. maculatus Amc | NHMW-Inv. No.2395 | South Annam, Vietnam | MF187404 |
A. maculatus Am26 |
|
Nha Trang, Bao Dai Villas Hotel, in garden, Vietnam | MZ567159 |
A. fimbriatus BMP |
|
Bach Ma Peak, Da Nang, Vietnam | MZ567160 |
A. longeligulatus TPP |
|
Tham Phet Po Thong, Klong Hard, Sa Kaeo, Thailand | MZ567161 |
A. pollex SMR |
|
Sra Morakot, Klongthom, Krabi, Thailand | MZ567162 |
A. pollex SML |
|
Koh 8, Similan islands, Phang-Nga, Thailand | MZ567163 |
A. pollex WTS |
|
Tham Sue Temple, Muang, Krabi, Thailand | MZ567164 |
?A. spininavis ABB |
|
Air Banun, Perak, Malaysia | MZ567165 |
Genus Atopochetus | |||
A. anaticeps SVL |
|
Srivilai temple, Chalermprakiet, Saraburi, Thailand | MF187405 |
A. dollfusii DOL | NHM | Cochinchina, Vietnam | MF187412 |
A. helix SPT |
|
Suan Pa Thong Pha Phum, Kanchanaburi, Thailand | MF187416 |
A. moulmeinensis TAK |
|
km 87, Tha Song Yang, Tak, Thailand | MF187417 |
A. setiferus HPT |
|
Hub Pa Tard, Lan-Sak, Uthaithani, Thailand | MF187419 |
A. spinimargo Ton27 |
|
Koh Yo, Songkhla, Thailand | MF187423 |
A. truncatus SML |
|
Koh 8, Similan islands, Phang-Nga, Thailand | MF187424 |
A. uncinatus KMR |
|
Khao Mar Rong, Bangsapan, Prachuapkhirikhan, Thailand | MF187425 |
A. weseneri Tos29 |
|
Supar Royal Beach Hotel, Khanom, Nakhonsrithammarat, Thailand | MF187431 |
Genus Aulacobolus | |||
A. uncopygus Auc | NHMW-Inv. No.2375 | Nilgiris, South India, India | MF187433 |
Genus Benoitolus | |||
B. birgitae BBG |
|
Chiang Dao, Chiang-Mai, Thailand | MT328992 |
Genus Coxobolellus | |||
C. albiceps Stpw |
|
Tham Pha Tub, Muang District, Nan Province, Thailand (green individual) | MT328994 |
C. compactogonus SKR |
|
Sakaerat Environmental Research Station, Wang Nam Khiao District, Nakhon Ratchasima Province, Thailand | MT328998 |
C. fuscus HKK |
|
Kroeng Krawia waterfall, Sangkhla Buri District, Kanchanaburi Province, Thailand | MT328999 |
C. nodosus SPW |
|
Chao Por Phawo Shrine, Mae Sot District, Tak Province, Thailand | MT329000 |
C. serratus KKL |
|
Khao Kalok, Pran Buri District, Prachuap Khiri Khan Province, Thailand | MT329001 |
C. simplex TNP |
|
Tham Pha Pha Ngam, Mae Prik District, Lampang Province, Thailand | MT329002 |
C. tenebris TPL |
|
Wat Tham Phrom Lok Khao Yai, Sai Yok District, Kanchanaburi Province, Thailand | MT329004 |
C. tigris TYE |
|
Tham Yai I, Pathio District, Chumphon Province, Thailand | MT329006 |
C. transversalis Stpg |
|
Tham Pha Tub, Muang District, Nan Province, Thailand | MT329007 |
C. valvatus BRC |
|
Tham Borichinda, Chom Thong District, Chiang-Mai Province, Thailand | MT329008 |
Genus Leptogoniulus | |||
L. sorornus BTN |
|
Botanical Garden, Penang, Malaysia | MF187434 |
Genus Litostrophus | |||
L. chamaeleon PPT |
|
Phu Pha terb, Mukdahan, Thailand | MF187436 |
L. saraburensis PKS |
|
Phukhae Botanical Garden, Saraburi, Thailand | MF187438 |
L. segregatus Ls19 |
|
Koh Kut, Trad, Thailand | MF187440 |
Genus Macrurobolus gen. nov. | |||
M. macrurus comb. nov. |
|
Wat Tham Inthanin, Mae Sot District, Tak Province, Thailand | MZ905519 |
Genus Madabolus | |||
M. maximus Mm4 |
|
de Toliara Province, Parc National de Bermaraha, South Bank of Manambolo River, Near Tombeau Vazimba, Madagascar | MF187441 |
Genus Narceus | |||
N. annularis | NC_003343.1 | ||
Genus Parabolus | |||
P. dimorphus Pd34 |
|
Dar es Salaam, Tanzania | MF187442 |
Genus Paraspirobolus | |||
P. lucifugus | AB608779.1 | ||
Genus Pelmatojulus | |||
P. tigrinus Pt2 |
|
Southern part of the Comoé N.P., 30 km north of Kakpin, Côte d’Ivoire | MF187443 |
P. togoensis Pto6 |
|
Biakpa, Ghana | MF187444 |
Genus Pseudospirobolellus | |||
P. avernus GPG |
|
Gua Pulai, Gua Musang, Kelantan, Malaysia | MT329011 |
Pseudospirobolellus sp. KCS |
|
Koh Chuang, Sattahip, Chonburi, Thailand | MT329012 |
Genus Rhinocricus | |||
R. parcus Rp49 |
|
Puerto Rico, Usa | MF187449 |
Genus Trachelomegalus | |||
Trachelomgalus sp. Tr54 |
|
Borneo Sabah, Malaysia | MF187445 |
Genus Trigoniulus | |||
T. corallinus Tco15 |
|
Vientiane, Laos | MF187446 |
Outgroup | |||
Genus Anurostreptus | |||
A. barthelemyae Tlb |
|
Thale-Ban N.P., Khuan-Don, Satun, Thailand | KC519469 |
Genus Chonecambala | |||
C. crassicauda Ttp |
|
Ton-Tong waterfall, Pua, Nan, Thailand | KC519467 |
Genus Thyropygus | |||
T. allevatus Bb |
|
BangBan, Ayutthaya, Thailand | KC519479 |
The COI data included 48 specimens, representing 17 genera and 40 nominal species of ingroup taxa (Table
CodonCode Aligner (v. 4.0.4, CodonCode Corporation) was used to assemble the forward and reverse sequences and to check for errors and ambiguities. Sequences were checked with the Basic Local Alignment Search Tool (BLAST) provided by NCBI and compared with reference sequences in GenBank. Next, sequences were aligned using MUSCLE (v. 3.6, see http://www.drive5.com/muscle;
Phylogenetic trees were constructed using maximum likelihood (ML), Bayesian inference (BI), and neighbor-joining (NJ). The shape parameter of the gamma distribution, based on 16 rate categories, was estimated using maximum-likelihood analysis. ML trees were inferred with RAxML (v. 8.2.12, see http://www.phylo.org/index.php/tools/raxmlhpc2_tgb.html;
For ML and NJ trees we consider branches with bootstrap values (BV) of ≥ 70% to be well supported (
The uncorrected p-distance between the sequences ranged from 0.03 to 0.25 (Tables
Estimates of COI sequence divergences (uncorrected p-distances) within and among Pachybolidae species and related taxa (rounded to two decimals).
1 | Macrurobolus macrurus comb. nov. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 |
2 | Apeuthes longeligulatus TPP | 0.18 | ||||||||||||||||||||||||||
3 | ?Apeuthes spininavis ABB | 0.18 | 0.14 | |||||||||||||||||||||||||
4 | Apeuthes fimbriatus BMP1 | 0.21 | 0.15 | 0.16 | ||||||||||||||||||||||||
5 | Apeuthes pollex SML | 0.18 | 0.14 | 0.15 | 0.15 | |||||||||||||||||||||||
6 | Apeuthes pollex SMR | 0.18 | 0.14 | 0.14 | 0.15 | 0.06 | ||||||||||||||||||||||
7 | Apeuthes pollex WTS | 0.18 | 0.15 | 0.15 | 0.15 | 0.04 | 0.07 | |||||||||||||||||||||
8 | Apeuthes maculatus Amc | 0.17 | 0.11 | 0.12 | 0.14 | 0.11 | 0.11 | 0.11 | ||||||||||||||||||||
9 | Apeuthes maculatus Am26 | 0.18 | 0.13 | 0.14 | 0.15 | 0.13 | 0.13 | 0.13 | 0.03 | |||||||||||||||||||
10 | Atopochetus anaticeps SVL | 0.16 | 0.20 | 0.19 | 0.23 | 0.18 | 0.18 | 0.19 | 0.19 | 0.20 | ||||||||||||||||||
11 | Atopochetus dollfusii DOL | 0.14 | 0.19 | 0.20 | 0.22 | 0.19 | 0.19 | 0.20 | 0.20 | 0.21 | 0.11 | |||||||||||||||||
12 | Atopochetus helix SPT | 0.15 | 0.23 | 0.19 | 0.22 | 0.20 | 0.21 | 0.20 | 0.21 | 0.22 | 0.14 | 0.13 | ||||||||||||||||
13 | Atopochetus moulmeinensis TAK | 0.17 | 0.22 | 0.22 | 0.23 | 0.22 | 0.23 | 0.23 | 0.22 | 0.23 | 0.14 | 0.12 | 0.15 | |||||||||||||||
14 | Atopochetus setiferus HPT | 0.14 | 0.20 | 0.20 | 0.22 | 0.18 | 0.18 | 0.19 | 0.19 | 0.20 | 0.08 | 0.09 | 0.14 | 0.13 | ||||||||||||||
15 | Atopochetus spinimargo Ton27 | 0.17 | 0.22 | 0.22 | 0.22 | 0.21 | 0.20 | 0.20 | 0.22 | 0.22 | 0.15 | 0.14 | 0.14 | 0.16 | 0.14 | |||||||||||||
16 | Atopochetus truncatus SML | 0.15 | 0.20 | 0.20 | 0.22 | 0.20 | 0.19 | 0.21 | 0.19 | 0.21 | 0.13 | 0.10 | 0.12 | 0.14 | 0.12 | 0.14 | ||||||||||||
17 | Atopochetus uncinatus KMR | 0.16 | 0.21 | 0.20 | 0.21 | 0.19 | 0.20 | 0.20 | 0.20 | 0.22 | 0.13 | 0.14 | 0.14 | 0.15 | 0.13 | 0.15 | 0.13 | |||||||||||
18 | Atopochetus weseneri Tos29 | 0.16 | 0.21 | 0.20 | 0.21 | 0.21 | 0.20 | 0.22 | 0.20 | 0.21 | 0.14 | 0.12 | 0.14 | 0.13 | 0.12 | 0.16 | 0.10 | 0.13 | ||||||||||
19 | Aulacobolus uncopygus Auc | 0.17 | 0.17 | 0.18 | 0.20 | 0.16 | 0.17 | 0.17 | 0.17 | 0.18 | 0.18 | 0.18 | 0.20 | 0.21 | 0.19 | 0.22 | 0.19 | 0.20 | 0.22 | |||||||||
20 | Coxobolellus albiceps Stpw | 0.21 | 0.18 | 0.21 | 0.20 | 0.18 | 0.17 | 0.18 | 0.18 | 0.19 | 0.20 | 0.22 | 0.22 | 0.24 | 0.22 | 0.23 | 0.21 | 0.21 | 0.22 | 0.18 | ||||||||
21 | Coxobolellus compactogonus SKR | 0.23 | 0.18 | 0.19 | 0.21 | 0.19 | 0.18 | 0.19 | 0.19 | 0.21 | 0.21 | 0.21 | 0.22 | 0.24 | 0.21 | 0.23 | 0.21 | 0.21 | 0.22 | 0.19 | 0.14 | |||||||
22 | Coxobolellus fuscus HKK | 0.22 | 0.19 | 0.20 | 0.20 | 0.17 | 0.18 | 0.18 | 0.20 | 0.21 | 0.20 | 0.22 | 0.22 | 0.24 | 0.20 | 0.23 | 0.23 | 0.20 | 0.23 | 0.19 | 0.12 | 0.13 | ||||||
23 | Coxobolellus nodosus SPW | 0.21 | 0.18 | 0.20 | 0.22 | 0.18 | 0.19 | 0.19 | 0.20 | 0.20 | 0.21 | 0.20 | 0.21 | 0.24 | 0.21 | 0.23 | 0.22 | 0.22 | 0.23 | 0.18 | 0.11 | 0.13 | 0.11 | |||||
24 | Coxobolellus serratus KKL | 0.21 | 0.18 | 0.20 | 0.20 | 0.18 | 0.18 | 0.18 | 0.18 | 0.20 | 0.20 | 0.21 | 0.22 | 0.23 | 0.20 | 0.23 | 0.21 | 0.22 | 0.22 | 0.19 | 0.13 | 0.14 | 0.12 | 0.13 | ||||
25 | Coxobolellus simplex TNP | 0.20 | 0.18 | 0.18 | 0.20 | 0.18 | 0.18 | 0.18 | 0.19 | 0.20 | 0.21 | 0.22 | 0.21 | 0.23 | 0.22 | 0.23 | 0.23 | 0.23 | 0.22 | 0.20 | 0.13 | 0.12 | 0.12 | 0.12 | 0.11 | |||
26 | Coxobolellus tenebris TPL | 0.22 | 0.19 | 0.18 | 0.21 | 0.18 | 0.18 | 0.18 | 0.18 | 0.20 | 0.21 | 0.22 | 0.23 | 0.25 | 0.22 | 0.24 | 0.23 | 0.23 | 0.23 | 0.19 | 0.13 | 0.10 | 0.12 | 0.12 | 0.14 | 0.11 | ||
27 | Coxobolellus tigris TYE | 0.23 | 0.19 | 0.21 | 0.22 | 0.20 | 0.20 | 0.20 | 0.20 | 0.20 | 0.19 | 0.22 | 0.22 | 0.25 | 0.21 | 0.24 | 0.22 | 0.22 | 0.22 | 0.21 | 0.13 | 0.14 | 0.12 | 0.13 | 0.12 | 0.13 | 0.15 | |
28 | Coxobolellus transversalis Stpg | 0.21 | 0.18 | 0.20 | 0.21 | 0.18 | 0.18 | 0.19 | 0.18 | 0.19 | 0.20 | 0.20 | 0.20 | 0.23 | 0.21 | 0.21 | 0.20 | 0.22 | 0.22 | 0.18 | 0.08 | 0.15 | 0.12 | 0.11 | 0.12 | 0.12 | 0.14 | 0.13 |
29 | Coxobolellus valvatus BRC | 0.21 | 0.17 | 0.19 | 0.20 | 0.16 | 0.16 | 0.17 | 0.17 | 0.18 | 0.20 | 0.21 | 0.20 | 0.24 | 0.20 | 0.23 | 0.22 | 0.22 | 0.22 | 0.17 | 0.10 | 0.13 | 0.11 | 0.07 | 0.13 | 0.12 | 0.12 | 0.13 |
30 | Paraspirobolus lucifugus | 0.25 | 0.25 | 0.22 | 0.23 | 0.22 | 0.22 | 0.22 | 0.22 | 0.23 | 0.23 | 0.23 | 0.23 | 0.23 | 0.23 | 0.23 | 0.23 | 0.23 | 0.24 | 0.24 | 0.24 | 0.23 | 0.23 | 0.24 | 0.25 | 0.25 | 0.24 | 0.24 |
31 | Leptogoniulus sorornus BTN | 0.18 | 0.16 | 0.14 | 0.16 | 0.14 | 0.14 | 0.15 | 0.13 | 0.14 | 0.18 | 0.18 | 0.19 | 0.21 | 0.19 | 0.20 | 0.19 | 0.22 | 0.22 | 0.17 | 0.21 | 0.20 | 0.20 | 0.19 | 0.19 | 0.18 | 0.20 | 0.20 |
32 | Litostrophus chamaeleon PPT | 0.14 | 0.20 | 0.19 | 0.20 | 0.18 | 0.18 | 0.20 | 0.18 | 0.19 | 0.17 | 0.16 | 0.15 | 0.18 | 0.16 | 0.18 | 0.15 | 0.17 | 0.17 | 0.19 | 0.20 | 0.21 | 0.20 | 0.20 | 0.20 | 0.21 | 0.21 | 0.20 |
33 | Litostrophus saraburensis PKS | 0.11 | 0.18 | 0.18 | 0.20 | 0.18 | 0.17 | 0.18 | 0.16 | 0.17 | 0.16 | 0.15 | 0.15 | 0.17 | 0.15 | 0.16 | 0.14 | 0.16 | 0.18 | 0.18 | 0.18 | 0.20 | 0.19 | 0.19 | 0.20 | 0.20 | 0.20 | 0.20 |
34 | Litostrophus segregatus Ls19 | 0.13 | 0.19 | 0.19 | 0.20 | 0.18 | 0.18 | 0.19 | 0.18 | 0.20 | 0.13 | 0.13 | 0.15 | 0.16 | 0.13 | 0.15 | 0.14 | 0.14 | 0.17 | 0.18 | 0.21 | 0.21 | 0.21 | 0.21 | 0.20 | 0.22 | 0.21 | 0.21 |
35 | Madabolus maximus Mm4 | 0.19 | 0.20 | 0.18 | 0.20 | 0.19 | 0.19 | 0.20 | 0.20 | 0.21 | 0.21 | 0.20 | 0.19 | 0.22 | 0.22 | 0.21 | 0.20 | 0.20 | 0.22 | 0.18 | 0.20 | 0.23 | 0.22 | 0.21 | 0.22 | 0.22 | 0.24 | 0.22 |
36 | Narceus annularis | 0.20 | 0.21 | 0.20 | 0.20 | 0.21 | 0.21 | 0.21 | 0.21 | 0.22 | 0.23 | 0.20 | 0.21 | 0.22 | 0.21 | 0.20 | 0.20 | 0.21 | 0.21 | 0.20 | 0.22 | 0.23 | 0.21 | 0.23 | 0.22 | 0.22 | 0.23 | 0.22 |
37 | Parabolus dimorphus Pd34 | 0.20 | 0.21 | 0.21 | 0.22 | 0.19 | 0.19 | 0.19 | 0.20 | 0.21 | 0.18 | 0.20 | 0.19 | 0.22 | 0.18 | 0.20 | 0.21 | 0.19 | 0.21 | 0.19 | 0.18 | 0.22 | 0.19 | 0.18 | 0.20 | 0.20 | 0.20 | 0.17 |
38 | Pelmatojulus tigrinus Pt2 | 0.18 | 0.18 | 0.18 | 0.19 | 0.18 | 0.17 | 0.19 | 0.17 | 0.18 | 0.22 | 0.22 | 0.20 | 0.23 | 0.22 | 0.23 | 0.22 | 0.22 | 0.22 | 0.16 | 0.20 | 0.20 | 0.20 | 0.21 | 0.22 | 0.22 | 0.22 | 0.20 |
39 | Pelmatojulus togoensis Pto6 | 0.21 | 0.19 | 0.20 | 0.18 | 0.18 | 0.17 | 0.17 | 0.18 | 0.20 | 0.21 | 0.22 | 0.22 | 0.22 | 0.20 | 0.20 | 0.21 | 0.20 | 0.21 | 0.17 | 0.19 | 0.20 | 0.20 | 0.19 | 0.19 | 0.21 | 0.20 | 0.20 |
40 | Pseudospirobolellus avernus GPG | 0.21 | 0.21 | 0.19 | 0.23 | 0.19 | 0.20 | 0.20 | 0.20 | 0.22 | 0.21 | 0.22 | 0.22 | 0.23 | 0.21 | 0.23 | 0.22 | 0.23 | 0.23 | 0.20 | 0.20 | 0.21 | 0.20 | 0.21 | 0.20 | 0.21 | 0.21 | 0.20 |
41 | Pseudospirobolellus sp. KCS | 0.23 | 0.22 | 0.22 | 0.22 | 0.22 | 0.22 | 0.21 | 0.23 | 0.23 | 0.23 | 0.23 | 0.21 | 0.23 | 0.23 | 0.22 | 0.22 | 0.23 | 0.23 | 0.22 | 0.22 | 0.22 | 0.21 | 0.21 | 0.22 | 0.22 | 0.23 | 0.22 |
42 | Rhinocricus parcus Rp49 | 0.24 | 0.24 | 0.23 | 0.23 | 0.23 | 0.23 | 0.22 | 0.23 | 0.24 | 0.24 | 0.21 | 0.22 | 0.22 | 0.24 | 0.21 | 0.23 | 0.22 | 0.23 | 0.22 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.25 | 0.24 |
43 | Trachelomegalus sp. Tr54 | 0.19 | 0.20 | 0.19 | 0.20 | 0.19 | 0.19 | 0.20 | 0.20 | 0.22 | 0.19 | 0.18 | 0.17 | 0.20 | 0.19 | 0.18 | 0.18 | 0.18 | 0.18 | 0.20 | 0.21 | 0.22 | 0.24 | 0.23 | 0.22 | 0.22 | 0.23 | 0.24 |
44 | Trigoniulus corallinus Tco15 | 0.18 | 0.15 | 0.14 | 0.13 | 0.13 | 0.13 | 0.14 | 0.12 | 0.12 | 0.18 | 0.19 | 0.20 | 0.23 | 0.19 | 0.20 | 0.20 | 0.21 | 0.21 | 0.17 | 0.18 | 0.18 | 0.17 | 0.18 | 0.19 | 0.17 | 0.18 | 0.17 |
45 | Anurostreptus barthelemyae Tlb | 0.23 | 0.21 | 0.21 | 0.22 | 0.20 | 0.20 | 0.19 | 0.21 | 0.22 | 0.22 | 0.22 | 0.23 | 0.24 | 0.23 | 0.22 | 0.24 | 0.23 | 0.24 | 0.20 | 0.19 | 0.21 | 0.19 | 0.19 | 0.20 | 0.19 | 0.20 | 0.19 |
46 | Chonecambala crassicauda | 0.24 | 0.23 | 0.22 | 0.21 | 0.22 | 0.22 | 0.21 | 0.21 | 0.23 | 0.24 | 0.24 | 0.24 | 0.23 | 0.24 | 0.23 | 0.24 | 0.22 | 0.24 | 0.22 | 0.23 | 0.23 | 0.22 | 0.23 | 0.22 | 0.22 | 0.23 | 0.22 |
47 | Thyropygus allevatus Bb | 0.21 | 0.21 | 0.21 | 0.21 | 0.20 | 0.21 | 0.20 | 0.21 | 0.22 | 0.21 | 0.21 | 0.22 | 0.23 | 0.23 | 0.23 | 0.22 | 0.21 | 0.24 | 0.20 | 0.20 | 0.19 | 0.20 | 0.20 | 0.19 | 0.19 | 0.20 | 0.19 |
1 | Macrurobolus macrurus comb. nov. | 28 | 29 | 30 | 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 |
2 | Apeuthes longeligulatus TPP | |||||||||||||||||||
3 | ?Apeuthes spininavis ABB | |||||||||||||||||||
4 | Apeuthes fimbriatus BMP1 | |||||||||||||||||||
5 | Apeuthes pollex SML | |||||||||||||||||||
6 | Apeuthes pollex SMR | |||||||||||||||||||
7 | Apeuthes pollex WTS | |||||||||||||||||||
8 | Apeuthes maculatus Amc | |||||||||||||||||||
9 | Apeuthes maculatus Am26 | |||||||||||||||||||
10 | Atopochetus anaticeps SVL | |||||||||||||||||||
11 | Atopochetus dollfusii DOL | |||||||||||||||||||
12 | Atopochetus helix SPT | |||||||||||||||||||
13 | Atopochetus moulmeinensis TAK | |||||||||||||||||||
14 | Atopochetus setiferus HPT | |||||||||||||||||||
15 | Atopochetus spinimargo Ton27 | |||||||||||||||||||
16 | Atopochetus truncatus SML | |||||||||||||||||||
17 | Atopochetus uncinatus KMR | |||||||||||||||||||
18 | Atopochetus weseneri Tos29 | |||||||||||||||||||
19 | Aulacobolus uncopygus Auc | |||||||||||||||||||
20 | Coxobolellus albiceps Stpw | |||||||||||||||||||
21 | Coxobolellus compactogonus SKR | |||||||||||||||||||
22 | Coxobolellus fuscus HKK | |||||||||||||||||||
23 | Coxobolellus nodosus SPW | |||||||||||||||||||
24 | Coxobolellus serratus KKL | |||||||||||||||||||
25 | Coxobolellus simplex TNP | |||||||||||||||||||
26 | Coxobolellus tenebris TPL | |||||||||||||||||||
27 | Coxobolellus tigris TYE | |||||||||||||||||||
28 | Coxobolellus transversalis Stpg | |||||||||||||||||||
29 | Coxobolellus valvatus BRC | 0.11 | ||||||||||||||||||
30 | Paraspirobolus lucifugus | 0.24 | 0.23 | |||||||||||||||||
31 | Leptogoniulus sorornus BTN | 0.19 | 0.19 | 0.24 | ||||||||||||||||
32 | Litostrophus chamaeleon PPT | 0.21 | 0.20 | 0.24 | 0.18 | |||||||||||||||
33 | Litostrophus saraburensis PKS | 0.18 | 0.19 | 0.24 | 0.18 | 0.11 | ||||||||||||||
34 | Litostrophus segregatus Ls19 | 0.20 | 0.20 | 0.25 | 0.18 | 0.11 | 0.09 | |||||||||||||
35 | Madabolus maximus Mm4 | 0.21 | 0.20 | 0.24 | 0.20 | 0.19 | 0.18 | 0.20 | ||||||||||||
36 | Narceus annularis | 0.22 | 0.22 | 0.21 | 0.21 | 0.20 | 0.20 | 0.21 | 0.20 | |||||||||||
37 | Parabolus dimorphus Pd34 | 0.19 | 0.18 | 0.25 | 0.21 | 0.19 | 0.18 | 0.20 | 0.17 | 0.20 | ||||||||||
38 | Pelmatojulus tigrinus Pt2 | 0.21 | 0.19 | 0.24 | 0.19 | 0.20 | 0.20 | 0.20 | 0.18 | 0.19 | 0.19 | |||||||||
39 | Pelmatojulus togoensis Pto6 | 0.20 | 0.18 | 0.25 | 0.18 | 0.18 | 0.18 | 0.19 | 0.19 | 0.20 | 0.18 | 0.17 | ||||||||
40 | Pseudospirobolellus avernus GPG | 0.20 | 0.21 | 0.22 | 0.19 | 0.23 | 0.21 | 0.21 | 0.21 | 0.22 | 0.23 | 0.20 | 0.21 | |||||||
41 | Pseudospirobolellus sp. KCS | 0.22 | 0.22 | 0.22 | 0.21 | 0.23 | 0.22 | 0.22 | 0.24 | 0.22 | 0.21 | 0.22 | 0.22 | 0.14 | ||||||
42 | Rhinocricus parcus Rp49 | 0.25 | 0.24 | 0.22 | 0.22 | 0.22 | 0.23 | 0.23 | 0.22 | 0.20 | 0.23 | 0.21 | 0.22 | 0.22 | 0.21 | |||||
43 | Trachelomegalus sp. Tr54 | 0.22 | 0.23 | 0.24 | 0.21 | 0.18 | 0.17 | 0.15 | 0.21 | 0.21 | 0.21 | 0.19 | 0.21 | 0.22 | 0.20 | 0.22 | ||||
44 | Trigoniulus corallinus Tco15 | 0.17 | 0.16 | 0.23 | 0.14 | 0.18 | 0.16 | 0.17 | 0.18 | 0.20 | 0.19 | 0.18 | 0.17 | 0.23 | 0.22 | 0.23 | 0.20 | |||
45 | Anurostreptus barthelemyae Tlb | 0.19 | 0.18 | 0.23 | 0.22 | 0.21 | 0.20 | 0.22 | 0.22 | 0.21 | 0.21 | 0.21 | 0.20 | 0.22 | 0.21 | 0.23 | 0.23 | 0.19 | ||
46 | Chonecambala crassicauda | 0.22 | 0.21 | 0.23 | 0.21 | 0.23 | 0.22 | 0.24 | 0.24 | 0.23 | 0.21 | 0.22 | 0.24 | 0.23 | 0.23 | 0.23 | 0.22 | 0.22 | 0.19 | |
47 | Thyropygus allevatus Bb | 0.20 | 0.19 | 0.22 | 0.20 | 0.21 | 0.20 | 0.22 | 0.21 | 0.20 | 0.21 | 0.23 | 0.21 | 0.22 | 0.22 | 0.21 | 0.24 | 0.20 | 0.15 | 0.20 |
PartitionFinder indicated that the best substitution model for BI analysis was GTR+ G. The ML, BI, and NJ trees were congruent with respect to some of the well-supported branches (by visual inspection of the branching pattern). Yet, in several instances BI provided good support for branches that were not well-supported by both ML and NJ (e.g., the Litostrophus + Benoitolus clade or the Coxobolellus + Pseudospirobolellus clade).
In the phylogenetic trees (Fig.
Phylogenetic relationships of pachybolid and several other spirobolidan millipede species based on maximum likelihood analysis (ML) of a 660 bp COI gene fragment. Numbers at nodes indicate branch support based on bootstrapping (ML) / posterior probabilities (BI) / bootstrapping (NJ). Scale bar: 0.3 substitutions/site. # indicates branches with < 50% ML and NJ bootstrap support or < 0.95 posterior probability, - indicates non-supported branches. The coloured areas mark the Pseudospirobolellidae (minus Benoitolus) (purple), Trigoniulinae (red), and non-trigoniuline Pachybolidae (plus Benoitolus) (yellow).
Irrespective of the in- or exclusion of Benoitolus, Macrurobolus macrurus comb. nov. is nested within a clade comprising Litostrophus and Atopochetus. Yet, this clade is poorly supported by ML, well supported (but just so) by NJ, and convincingly well supported by BI. The position of M. macrurus comb. nov. within this clade, however, is poorly supported by the three methods.
Order SPIROBOLIDA Bollman, 1893
Suborder TRIGONIULIDEA Attems, 1909
A genus of Pachybolidae characterised by the following combination of characters: preanal ring with long process protruding beyond anal valves; the anterior gonopod telopodite distally abruptly narrowed, forming an extremely long, slender, elevated process curved caudad.
The generic name is a combination of the name of the type species and “-bolus”, the ending of many pachybolid genus names.
Macrurobolus macrurus (Pocock, 1893) comb. nov.
Spirobolus macrurus
Tonkinbolus macrurus:
Atopochetus macrurus:
Macrurobolus macrurus
The original description was based exclusively on a female from “Kawkareet” (Tenasserim), Myanmar (see Distribution section for information on this locality).
Thailand, 1 ♂, 3 ♀♀; Tak Province, Mae Sot District, Wat Tham Inthanin; 16°45'59"N, 98°40'21"E; 660 m a.s.l.; 27 July 2016; P. Pimvichai, T. Backeljau and P. Prasankok leg. (
Adult male with 51 podous rings, no apodous rings. Length ca 11 cm, diameter ca 9.0 mm. Adult females with 48–51 podous rings, no apodous rings. Length ca 10–11 cm, diameter ca 10.0–10.4 mm.
Head capsule smooth, area below antennal sockets with wrinkles (Fig.
External morphology of a male Macrurobolus macrurus comb. nov. from Wat Tham Inthanin, Thailand,
Collum smooth, with a marginal furrow along lateral part of anterior margin; lateral lobes narrowly rounded, extending as far ventrad as the ventral margin of body ring 2.
Body rings 2–5 ventrally concave, hence with distinct ventrolateral “corners”. Body rings very smooth, parallel-sided in dorsal view. Prozona smooth. ‘Tergo-pleural’ suture visible on pro- and mesozona; mesozona ventrally with fine oblique striae, dorsally punctate; metazona ventrally with fine longitudinal striae, otherwise smooth. “Pleural” parts of rings with fine oblique striae. Sterna transversely striate. Ozopores from ring 6, situated in mesozona, ca 1/2 pore diameter in front of metazona (mentioned as “the repugnatorial pores situated in front of the transverse sulcus” by
Telson smooth; preanal ring with slightly concave dorsal profile, with thick and long process protruding beyond anal valves (Fig.
Legs (Fig.
Colour. Living animal reddish brown except for grey pro- and mesozona (Fig.
Male sexual characters. Tarsus from third to before the last 4 body rings with large ventral soft pad occupying entire ventral surface. Body ring 7 entirely fused ventrally, no trace of a suture. Tip of anterior gonopods visible when the animal is stretched out (not when it is rolled up).
Anterior gonopods (Fig.
Male (A–F, H–L) and female (G) genital parts of Macrurobolus macrurus comb. nov. (specimens from Wat Tham Inthanin, Thailand,
Posterior gonopods (Fig.
Female vulvae (Fig.
The GenBank accession number of the COI barcode of the Thai specimen is MZ905519 (voucher code
. Found under leaf litter.
This specimen is labelled as “ex typ” in the
Tak Province, Thailand; Kawkareet (Tenasserim) and Meetan, Myanmar (Fig.
The male specimen of Spirobolus macrurus from Meetan in
The new male specimen from Thailand and the old specimen from Myanmar share the long preanal ring process with the female type specimen, which is a remarkable character for a pachybolid, since most pachybolid genera (except Aulacobolus Pocock, 1903 and Trachelomegalus Silvestri, 1896) have a short preanal ring process. So, in this respect, Macrurobolus gen. nov. is clearly differentiated from most other pachybolid genera, including Atopochetus and Litostrophus, the two genera with which Macrurobolus gen. nov. appears the be most closely related in our phylogenetic tree (Fig.
The interpretation of Macrurobolus as a separate genus is somehow in line with the COI tree (Fig.
Estimates of COI mean sequence divergences within (on diagonal) and among (below diagonal) pachybolid and pseudospirobolellid genera (range in parentheses) (data based on
1 | 2 | 3 | 4 | 5 | |
1. Apeuthes | 14 (11–16) | ||||
2. Atopochetus | 21 (18–23) | 13 (8–16) | |||
3. Coxobolellus | 19 (16–22) | 22 (19–25) | 12 (7–15) | ||
4. Litostrophus | 19 (16–20) | 16 (13–18) | 20 (18–22) | 11 (9–11) | |
5. Pseudospirobolellus | 21 (19–23) | 22 (21–23) | 21 (20–23) | 22 (21–23) | 14 |
6. Macrurobolus macrurus comb. nov. | 18 (18–21) | 15 (14–17) | 21 (20–23) | 13 (11–14) | 22 (21–23) |
In conclusion, this study suggests that
This research was funded by the Thailand Science Research and Innovation (TSRI) together with Mahasarakham University as a TRF Research Career Development Grant (2019–2022; RSA6280051) (to P. Pimvichai). Additional funding came from the Royal Belgian Institute of Natural Sciences (RBINS). We thank, Pongpun Prasankok for assistance in collecting material. We are indebted to Julien Cillis (RBINS) for help with SEM photographs, to Yves Barette (RBINS) for help with gonopod photographs and to Thita Krutchuen for the excellent drawings. Last but not least, we thank Thomas Wesener (Bonn) and Sergei Golovatch (Moscow) for their helpful reviews of this paper.
Redescription of the giant SE Asian millipede Spirobolus macrurus Pocock, 1893 and its assignment to the new genus Macrurobolus gen. nov. (Diplopoda, Spirobolida, Pachybolidae)
Data type: Jpg file.
Explanation note: Phylogenetic relationships of pachybolid and several other spirobolidan millipede species (excluding Benoitolus birgitae) based on maximum likelihood analysis (ML) of a 660 bp COI gene fragment.
Table S2
Data type: Xlsx file.
Explanation note: Estimates of COI sequence divergences (uncorrected p-distances) within and among Pachybolidae species and related taxa.