Corresponding author: Shiuh-Feng Shiao (
Academic editor: A. Schmidt-Rhaesa
Chiu M-C, Huang C-G, Wu W-J, Lin Z-H, Chen H-W, Shiao S-F (2020) A new millipede-parasitizing horsehair worm,
In addition to the two previously described species of horsehair worm (
The definitive hosts of
Free-living adults of
Horsehair worm samples were identified visually and collected from the ground. In total, 21 free-living adults (17 male and 4 female adults) were collected for morphological examination and DNA sequencing (detailed information provided in Table
Genomic DNA from a 1-cm mid-body section of each worm was extracted using an ALS Tissue Genomic DNA Extraction Kit (Pharmigene, Kaohsiung, Taiwan). The partial cytochrome c oxidase subunit I (
In addition to sequencing three free-living adult worms and six immature worms recovered from millipede hosts (242–457 high-quality base pairs), we obtained high-quality CO1 sequences (>500 base pairs) from 18 adult free-living individuals to be used in our phylogenetic analysis and estimates of intraspecific genetic distances. Pairwise distance matrices of
Seasonal occurrence of free-living adults was estimated by counting (and removing) free-living adults (living or dead) on the ground in Dinghu, Alishan township, Chiayi county, Taiwan (
Dinghu (
Partial bodies of the holotype and allotype were deposited at the National Museum of Natural Science, Taichung, Taiwan. Paratypes were deposited at the National Museum of Natural Science, Taichung, Taiwan and Lake Biwa Museum, Shiga, Japan (Table
Collection date | GenBank no. | Locality | Longitude and latitude | Collector | Depository | Sex | Status | Length (mm) |
---|---|---|---|---|---|---|---|---|
20-XI-2017 |
|
Dasyueshan (Heping, Taichung, Taiwan) |
|
Ta-Chih Chen | NMNS | M | Free-living adult | 430 |
26-XI-2008 |
|
Hongshi trail (Haituan, Taitung, Taiwan) |
|
Po-Yen Chen | NMNS | M | Free-living adult | 744 |
22-I-2008 |
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Shihjhuo (Zhuqi, Chiayi, Taiwan) |
|
Yu-Hsuan Tsai | NMNS | M | Free-living adult | 860 |
9-II-2007 |
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Shihjhuo (Zhuqi, Chiayi, Taiwan) |
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Yu-Hsuan Tsai | NMNS | F | Free-living adult | 707 |
8-XII-2017 |
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Dinghu (Alishan, Chiayi, Taiwan) |
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Ming-Chung Chiu | LBM | M | Free-living adult | 771 |
8-XII-2017 |
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Dinghu (Alishan, Chiayi, Taiwan) |
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Ming-Chung Chiu | NMNS | M | Free-living adult | 734 |
8-XII-2017 |
|
Dinghu (Alishan, Chiayi, Taiwan) |
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Ming-Chung Chiu | NMNS | M | Free-living adult | 726 |
17-XII-2013 |
|
Fenqihu (Zhuqi, Chiayi, Taiwan) |
|
Hua-Te Fang | LBM | M | Free-living adult | 803 |
17-XII-2013 |
|
Fenqihu (Zhuqi, Chiayi, Taiwan) |
|
Hua-Te Fang | LBM | M | Free-living adult | 756 |
17-XII-2013 |
|
Fenqihu (Zhuqi, Chiayi, Taiwan) |
|
Hua-Te Fang | NMNS | M | Free-living adult | 594 |
17-XII-2013 |
|
Fenqihu (Zhuqi, Chiayi, Taiwan) |
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Hua-Te Fang | NMNS | M | Free-living adult | 383 |
17-XII-2013 |
|
Fenqihu (Zhuqi, Chiayi, Taiwan) |
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Hua-Te Fang | NMNS | M | Free-living adult | 676 |
17-XII-2013 |
|
Fenqihu (Zhuqi, Chiayi, Taiwan) |
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Hua-Te Fang | NMNS | M | Free-living adult | 474 |
18-XII-2017 |
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Fenqihu (Zhuqi, Chiayi, Taiwan) |
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Ming-Chung Chiu | NMNS | M | Free-living adult | 749 |
18-XII-2017 |
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Fenqihu (Zhuqi, Chiayi, Taiwan) |
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Ming-Chung Chiu | NMNS | F | Free-living adult | 666 |
18-XII-2017 |
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Fenqihu (Zhuqi, Chiayi, Taiwan) |
|
Ming-Chung Chiu | NMNS | F | Free-living adult | 717 |
18-XII-2016 |
|
Xitou (Lugu, Nantou, Taiwan) |
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Ming-Chung Chiu | LBM | M | Free-living adult | 498 |
18-XII-2016 |
|
Xitou (Lugu, Nantou, Taiwan) |
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Ming-Chung Chiu | NMNS | M | Free-living adult | 403 |
18-XII-2016 |
|
Xitou (Lugu, Nantou, Taiwan) |
|
Ming-Chung Chiu | LBM | F | Free-living adult | 549 |
9-II-2008 |
|
Xitou (Lugu, Nantou, Taiwan) |
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Ming-Chung Chiu | NMNS | M | Free-living adult | 572 |
10-XII-2011 |
|
Xitou (Lugu, Nantou, Taiwan) |
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Ming-Chung Chiu | NMNS | M | Free-living adult | 502 |
17-III-2019 |
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Xitou (Lugu, Nantou, Taiwan) |
|
Zhao-Hui Lin | NMNS | - | Dead worm in host | - |
23-VII-2018 |
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Shihjhuo (Zhuqi, Chiayi, Taiwan) |
|
Yu-Wei Li | NMNS | - | Immature worm | 660 |
28-VII-2018 |
|
Shihjhuo (Zhuqi, Chiayi, Taiwan) |
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Yu-Wei Li | NMNS | - | Immature worm | 894 |
28-VII-2018 |
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Shihjhuo (Zhuqi, Chiayi, Taiwan) |
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Yu-Wei Li | NMNS | - | Immature worm | 420 |
28-VII-2018 |
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Shihjhuo (Zhuqi, Chiayi, Taiwan) |
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Yu-Wei Li | NMNS | - | Immature worm | 442 |
28-VII-2018 |
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Shihjhuo (Zhuqi, Chiayi, Taiwan) |
|
Yu-Wei Li | NMNS | - | Immature worm | 426 |
LBM: Lake Biwa Museum; NMNS: National Museum of Natural Science. 1 Holotype.
The specific name is the combination of
Anterior end of male
Anterior end columnar and spherical; anterior tip white (white cap) with a dark -brown collar and a vertical white stripe on the ventral side (Fig.
Cuticle in mid-body ornamented with a dorsal and a ventral dark pigment line; white spots scattered across entire body surface (Figs
Posterior end divided into two tail lobes (Fig.
Posterior end of male
Mid-body of male
Female
Field observation of
Immature stages of
List of
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Myanmar nematomorph | |
Out group | ||
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*
The partial
Phylogenetic relationship of
Free-living adult worms frequently aggregate and mate on wet ground (Fig.
The 21 free-living
Intra- and interspecific mean
Species/Clade | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | |
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1 |
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2 | 0.285 |
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3 | 0.312 | 0.217 |
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4 | 0.293 | 0.297 | 0.275 |
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5 | 0.308 | 0.208 | 0.249 | 0.157 |
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6 | 0.272 | 0.165 | 0.211 | 0.227 | 0.222 |
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7 | 0.293 | 0.257 | 0.251 | 0.255 | 0.228 | 0.259 |
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8 |
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0.232 | 0.209 | 0.265 | 0.250 | 0.230 | 0.222 | 0.238 |
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9 | 0.265 | 0.203 | 0.307 | 0.338 | 0.253 | 0.244 | 0.251 | 0.122 |
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10 |
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0.277 | 0.229 | 0.288 | 0.337 | 0.274 | 0.238 | 0.289 | 0.231 | 0.249 |
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11 |
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0.316 | 0.260 | 0.298 | 0.288 | 0.269 | 0.274 | 0.304 | 0.264 | 0.323 | 0.337 | – | |||||||||||
12 | 0.352 | 0.260 | 0.313 | 0.370 | 0.289 | 0.340 | 0.330 | 0.256 | 0.290 | 0.271 | 0.323 | – | |||||||||||
13 | 0.329 | 0.302 | 0.290 | 0.373 | 0.317 | 0.344 | 0.365 | 0.294 | 0.336 | 0.277 | 0.301 | 0.246 | – | ||||||||||
14 | 0.424 | 0.416 | 0.462 | 0.547 | 0.441 | 0.443 | 0.478 | 0.375 | 0.412 | 0.348 | 0.455 | 0.343 | 0.414 | – | |||||||||
15 | 0.332 | 0.366 | 0.387 | 0.420 | 0.376 | 0.396 | 0.302 | 0.357 | 0.359 | 0.379 | 0.439 | 0.375 | 0.434 | 0.441 | – | ||||||||
16 | 0.384 | 0.325 | 0.327 | 0.453 | 0.371 | 0.336 | 0.345 | 0.347 | 0.348 | 0.331 | 0.376 | 0.332 | 0.376 | 0.372 | 0.424 | – | |||||||
17 | 0.334 | 0.375 | 0.365 | 0.370 | 0.334 | 0.407 | 0.364 | 0.302 | 0.363 | 0.333 | 0.380 | 0.323 | 0.358 | 0.333 | 0.308 | 0.290 | – | ||||||
18 | 0.375 | 0.300 | 0.344 | 0.393 | 0.373 | 0.294 | 0.388 | 0.388 | 0.367 | 0.369 | 0.405 | 0.384 | 0.390 | 0.374 | 0.403 | 0.312 | 0.301 | – | |||||
19 | 0.369 | 0.405 | 0.381 | 0.450 | 0.381 | 0.410 | 0.359 | 0.373 | 0.395 | 0.409 | 0.398 | 0.408 | 0.466 | 0.426 | 0.453 | 0.415 | 0.386 | 0.440 |
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20 | 0.337 | 0.348 | 0.391 | 0.436 | 0.384 | 0.372 | 0.368 | 0.333 | 0.368 | 0.345 | 0.339 | 0.334 | 0.385 | 0.324 | 0.404 | 0.357 | 0.327 | 0.344 | 0.377 |
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21 | 0.335 | 0.283 | 0.293 | 0.436 | 0.355 | 0.311 | 0.366 | 0.287 | 0.337 | 0.347 | 0.358 | 0.254 | 0.308 | 0.343 | 0.353 | 0.304 | 0.335 | 0.321 | 0.354 | 0.337 |
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22 |
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0.365 | 0.343 | 0.327 | 0.401 | 0.386 | 0.368 | 0.345 | 0.322 | 0.375 | 0.304 | 0.336 | 0.270 | 0.210 | 0.462 | 0.469 | 0.432 | 0.376 | 0.366 | 0.435 | 0.389 | 0.311 |
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-Indicates a single haplotype whose intraspecific distance could not be calculated.
The concentration of bristles and spines on the male tail lobes has been previously described in species from the Palaearctic (
Although the distribution pattern of the bristles is similar to that of
Seasonal occurrence of free-living adults of
In this study, the female adult oviposited in the water. The cysts found in the aquatic paratenic hosts and the eggs developing in water also suggest the life cycle of
We deeply appreciate the assistance provided by Hua-Te Fang, Po-Yen Chen, Yu-Hsuan Tsai, Ta-Chih Chen, and Yu-Wei Li during sample collection, Wei-Chun Chien during
Video S1
multimedia
Free-living adult of
Fasta 2
molecular data