Short Communication |
Corresponding author: Sihang Zhang ( eva@ynu.edu.cn ) Academic editor: Pavel Stoev
© 2024 Zhenfei Wu, Sihang Zhang, Fuxue Qin, Peiyun Cong.
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:
Wu Z, Zhang S, Qin F, Cong P (2024) A new epigean species of Trichopeltis Pocock, 1894 from southwest China (Diplopoda, Polydesmida, Cryptodesmidae). ZooKeys 1216: 17-26. https://doi.org/10.3897/zookeys.1216.128080
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A new species of Cryptodesmidae, Trichopeltis jiyue sp. nov., is described from the Ailaoshan National Nature Reserve in Yunnan Province, southwest China. The new species is distinguished from its congeners by the gonopodal coxae with two conspicuous wing-like processes, the relatively long, stout setae on the gonopodal coxae, gonopodal telopodites glabrous and four-branched, and the acropodite curved caudolaterad. The new species is the second record of an epigean species of genus Trichopeltis Pocock, 1894 in China. An updated key is provided to all 14 presently known species.
Key, millipedes, taxonomy, Yunnan
The Polydesmida is one of the most diverse orders of Diplopoda (millipedes), containing about 5000 species in 30 families (
The Cryptodesmidae Karsch, 1880 is a relatively small family of Polydesmida comprising approximately 40 genera and 130 species (
Trichopeltis Pocock, 1894 is one of the tropical or subtropical genera of Asian Cryptodesmidae. Currently, this genus encompasses 13 species, mainly documented in Indonesia, Myanmar, Laos, Vietnam, Cambodia, southern China, and the Himalayas (
In this paper, we describe a new epigean species of Trichopeltis from southwest China and update the key to all known species in this genus. This new species represents the second record of an epigean species of Trichopeltis in China.
All specimens were collected from the Ailaoshan National Nature Reserve (24°32'N, 101°01'E, 2476 m above mean sea level) in Yunnan Province, southwest China. Yunnan Province is well known for its high biodiversity (
The live photographs were taken in the habitats of the described species using a SONY DSC-RX1R camera. All specimens were further studied and photographed with a Nikon SMZ25 stereomicroscope and Nikon DS-Ri2 microscope camera within the laboratory. Scanning electron microscope (SEM) images were taken with a FEI Quanta FEG 650 with gold coating. All figures are prepared with Affinity Photo v. 2 and Affinity Designer v. 2. The terminology used here follows that of
Order Polydesmida Leach, 1815
Family Cryptodesmidae Karsch, 1880
Genus Trichopeltis Pocock, 1894
Holotype : • ♂ (YNU-MD 0151), China, Yunnan Province, Pu’er City, Jingdong Yi Autonomous County, 24°54'78"N, 101°03'58"E, 2450 m elev., 4.X.2021, leg. Peiyun Cong, Sihang Zhang, Zhenfei Wu & Fuxue Qin. Paratypes: • 4 ♂, 9 ♀ (YNU-MD 0152-165) same location as the holotype.
Jiyue (Chinese spelling) alludes to the bright white appearance when the animal emerges from the leaf mold, like the moon appearing from behind a dark rain cloud.
Trichopeltis is characterized by the relatively long and stout setae on the gonopodal coxae, with the posterior part having two conspicuous wing-like processes (cxp); gonopodal telopodites glabrous and four-branched; and the acropodite curved caudolaterad. The living animal is uniformly bright white.
Length of ♂ ca 17.2–17.8 mm, paratype ♀ ca 17.0–17.4 mm, width of midbody pro- and metazonae 2.2–2.4 mm and 5.3–5.4 mm (♂), 2.2–2.5 mm and 5.1–5.4 mm (♀), respectively.
Coloration
of tergites uniformly bright white (Fig.
Adults body with 20 segments, collum plus 17 podous and 1 apodous tergites, plus 1 telson. In width, head << collum < segment 2 < 3 < 4 < 5 < 6 < 7-17, thereafter body tapered towards telson.
Head
sparsely pilose, epicranial suture present (Fig.
SEM images of Trichopeltis jiyue sp. nov., ♂ holotype A head, dorsal view B collum and the second segment, dorsal view C segments 6–9, dorsal view D cross-section of segment 5, caudal view E antenna disc coeloconic sensilla, plan view F telson and anal, ventral view G limbus of segment 5, subventral view H claw of leg, subventral view I paraterga of segment 6, ventral view. Scale bars: 1 mm (A–D); 50 μm (E, H); 20 μm (G); 500 μm (F, I).
Collum
completely covering the head from above, inverted subtrapeziform, regularly convex at peripheric margin, caudal margin slightly concave (Fig.
Prozona of segments following collum finely shagreened, metazona densely tuberculate and setose; fore and caudolateral margins of collum, anterolateral, lateral and caudal margins of following paraterga of segments besides telson with obvious dentiform-lobulate lobules, smallest at mid-dorsal region and slightly larger bidirectionally at caudal margins of paraterga.
Dorsum
convex, postcollum paraterga flat, very broad and long, narrowly rounded laterally, axial line absent. Metatergal segments 2–16 with four or five irregular transverse rows of similarly small, spherical, setigerous tubercles. Tubercles decreasingly extend to paraterga, but each of the latter only with three or four irregular rows of similar tubercles (Fig.
Paraterga
very strongly developed (Fig.
Sterna
sparsely setose; axial line present; tergite stricture divided into pro- and metazone parts. Limbus, with a row of tongue-shaped lobules, microdenticulate apically (Fig.
Telson
(Fig.
Legs
(Fig.
Gonopods
complex (Figs
Gonopodal characters of Trichopeltis jiyue sp. nov., ♂ holotype, paratype. A, C right gonopod, sublateral and subfrontal views B left gonopod, subcaudal view D right gonopod, ventral view, coxite and telopodite divided by a notch E enlargement of box-E of A, prefemur sheet micro-setose on the surface F gonopod, ventral view from above G enlargement of box-G of A, corolliform solenomere H seminal groove I box-I of C, tripartite apical process. Abbreviations: p1, p2, p3, p4 = processes of telopodite; cp = corolliform pulvillus; cxp = coxa process; ms = microsetae; sg = seminal groove; tap = tripartite apical process; ca = cannula; cx = coxa; te = telopodite; n = notch. Scale bars: 500 μm (A–D, F); 50 μm (E, G); 100 μm (H, I).
The specimens were found on a stoney roadside, which some researchers usually walk around. As compared with virgin forests, the surroundings were relatively densely populated. However, the environment is undeveloped, and it the new species seemed abundant.
Modified after
1 | Tegument unpigmented, pallid to light yellowish; cavernicolous species | 2 |
– | Tegument clearly pigmented, bright white, red- or grey-brown to blackish; epigean species | 7 |
2 | Central parts of metaterga with 2–4 irregular, transverse rows of setigerous tubercles; gonopodal coxite as usual, at most with only few setae | 3 |
– | Central parts of metaterga with 5–6 irregular transverse rows of setigerous tubercles; gonopodal coxite unusually densely setose on lateral side; Yunnan, China | 6 |
3 | Paraterga declivous; tergal setae very long, about half as long as body diameter; gonopodal telopodite clearly twisted. Guizhou, China |
T. latellai |
– | Paraterga clearly upturned; tergal setae much shorter; gonopodal telopodite untwisted | 4 |
4 | Gonopodal telopodite with a hairy pulvillus; coxite short and squarish, without seta; central parts of metaterga with 4 irregular, transverse rows of setigerous tubercles. Guangxi, China | T. liangfengdong Liu & Wynne, 2019 |
– | Gonopodal telopodite without pulvillus | 5 |
5 | Central parts of metaterga with 2–3 subregular, transverse rows of setigerous tubercles; acropodite strongly condensed, tripartite | T. reflexus Liu, Golovatch & Tian, 2017 |
– | Central parts of metaterga with 3–4 irregular transverse rows of setigerous tubercles; Telopodite only slightly curved caudad, vaguely tripartite. Laos | T. cavernicola Golovatch, 2016 |
6 | Tergal setae long; gonopods relatively simple | T. bellus Liu, Golovatch & Tian, 2017 |
– | Tergal setae short; gonopods rather complex | 12 |
7 | Central parts of metaterga with 4–6 irregular, transverse rows of setigerous tubercles | 8 |
– | Central parts of metaterga with 2–3 irregular, transverse rows of setigerous tubercles | 11 |
8 | Gonopodal telopodite with evident branches | 13 |
– | Gonopodal telopodite without long branches | 9 |
9 | Central parts of metaterga with 4–5 subregular, transverse rows of setigerous tubercles; gonopodal telopodite with a conspicuous accessory seminal chamber and a pulvillus but devoid of denticles laterally or mesally. Laos | T. muratovi Golovatch & VandenSpiegel, 2017 |
– | Central parts of metaterga with 5–6 subregular, transverse rows of setigerous tubercles; gonopodal telopodite without accessory seminal chamber but with a pulvillus, also abundantly denticulate either laterally or mesally | 10 |
10 | Gonopodal telopodite abundantly denticulate on lateral face. Vietnam, Laos, and Cambodia and possibly endemic to the Indochina Peninsula | T. kometis Attems, 1938 |
– | Gonopodal telopodite abundantly denticulate on mesal face. Sumatra, Indonesia | T. bicolor Pocock, 1894 |
11 | Frontal margin of paraterga abundantly lobulated. Solenomere lobe-shaped, tip nearly pointed | T. feae Pocock, 1895 |
– | Frontal margin of paraterga entire, not lobulated. Solenomere axe-shaped, tip pointed | T. watsoni Pocock, 1895 |
12 | Each coxa with a conspicuous, high, curved, laterally densely setose process |
T. sutchariti |
– | Each coxa with a small process without setae | T. intricatus Liu, Golovatch & Tian, 2017 |
13 | Clearly 3-branched; solenomere long and slender | T. doriae Pocock, 1895 |
– | Clearly 4-branched; with two conspicuous wing-like process (wp) basal, one pan-shaped lobe on the inner side; acropodite reverse caudally against femorite, unfolded into sheet form. Yunnan, China | T. jiyue sp. nov. |
The Cryptodesmidae comprises about 40 genera. The new species can be assigned to the genus Trichopeltis Pocock, 1894 based on the lobulated and tuberculate-setose tergites, subcordiform gonopod aperture, four-branched telopodite, and coxa divided by a notch.
Amongst all known 14 species of Trichopeltis, T. jiyue sp. nov. is most similar to T. kometis Attems, 1938 (Golovatch & Akkari, 2016), T. doriae Pocock, 1895, T. intricatus Liu, Golovatch & Tian, 2017, T. sutchariti
The gonopodal telopodite of T. jiyue sp. nov. clearly differs from that of T. doriae in having four branches, in contrast to the gonopodal telopodite of T. doriae which bears three branches; also, it differs from T. muratovi in the telopodite, which has a conspicuous accessory seminal chamber, in contrast to the gonopodal telopodite of T. jiyue sp. nov., which is without a conspicuous accessory seminal chamber; furthermore, the gonopodal surface of the new species is relatively smooth, with dense microsetae, and differs from that of the abundantly denticulate gonopodal surface of T. kometis and T. bicolor Pocock, 1894.
Trichopeltis intricatus and T. sutchariti were also found in Yunnan Province, China. Compared to T. jiyue sp. nov., the body size of T. jiyue sp. nov. is much larger; the length of the adult is over 17 mm, the pro- and metazonae are over 2 and 5 mm long, respectively, which is much longer than T. intricatus. T. intricatus is relatively short, ca 10 mm long, with the width of midbody pro- and metazonae 1.5 and 2.5 mm, respectively. Furthermore, the tuberculations on the collum have up to 12 or 13 irregular, transverse rows, which is more differ than the eight to nine irregular, transverse rows of T. sutchariti. The characters of the gonopod reveal many obvious interspecific differences.
Trichopeltis jiyue sp. nov. is described from Ailaoshan National Nature Reserve in Yunnan Province, southwest China. It represents the second record of an epigean species of the genus Trichopeltis in China. An updated identification key (modified from
We thank Canchen Liao and Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences for providing us scientific research field. We appreciate the valuable comments and useful suggestions on our manuscript from the associate editor and the reviewers. Last but not least, we extend our deep gratitude to Professors Sergei Golovatch, Natdanai Likhitrakarn, and Pavel Stoev for invaluable constructive feedback, and to Dr. Christopher Glasby and Dr. Robert Forsyth for polishing and revising the English of the manuscript.
The authors have declared that no competing interests exist.
No ethical statement was reported.
This work is supported by the Yunling Scholar funding and a joint grant of YNU-Yunnan Government (202201BF070001-016).
Data curation: FQ. Writing - original draft: ZW. Writing - review and editing: SZ, PC.
Zhenfei Wu https://orcid.org/0009-0004-5586-6511
Sihang Zhang https://orcid.org/0000-0002-8230-6892
Fuxue Qin https://orcid.org/0009-0001-1140-3927
Peiyun Cong https://orcid.org/0000-0001-9910-6478
All of the data that support the findings of this study are available in the main text.