Gordius chiashanus

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Chiu M, Huang C, Wu W, Lin Z, Chen H, Shiao S (2020) A new millipede-parasitizing horsehair worm, Gordius chiashanus sp. nov., at medium altitudes in Taiwan (Nematomorpha, Gordiida). ZooKeys 941 : 25–48, doi. Versioned wiki page: 2020-06-16, version 184077, https://species-id.net/w/index.php?title=Gordius_chiashanus&oldid=184077 , contributors (alphabetical order): Pensoft Publishers.

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BibTeX:

@article{Chiu2020ZooKeys941,
author = {Chiu, Ming-Chung AND Huang, Chin-Gi AND Wu, Wen-Jer AND Lin, Zhao-Hui AND Chen, Hsuan-Wien AND Shiao, Shiuh-Feng},
journal = {ZooKeys},
publisher = {Pensoft Publishers},
title = {A new millipede-parasitizing horsehair worm, Gordius chiashanus sp. nov., at medium altitudes in Taiwan (Nematomorpha, Gordiida)},
year = {2020},
volume = {941},
issue = {},
pages = {25--48},
doi = {10.3897/zookeys.941.49100},
url = {https://zookeys.pensoft.net/articles.php?id=49100},
note = {Versioned wiki page: 2020-06-16, version 184077, https://species-id.net/w/index.php?title=Gordius_chiashanus&oldid=184077 , contributors (alphabetical order): Pensoft Publishers.}

}

RIS/ Endnote:

TY - JOUR
T1 - A new millipede-parasitizing horsehair worm, Gordius chiashanus sp. nov., at medium altitudes in Taiwan (Nematomorpha, Gordiida)
A1 - Chiu M
A1 - Huang C
A1 - Wu W
A1 - Lin Z
A1 - Chen H
A1 - Shiao S
Y1 - 2020
JF - ZooKeys
JA -
VL - 941
IS -
UR - http://dx.doi.org/10.3897/zookeys.941.49100
SP - 25
EP - 48
PB - Pensoft Publishers
M1 - Versioned wiki page: 2020-06-16, version 184077, https://species-id.net/w/index.php?title=Gordius_chiashanus&oldid=184077 , contributors (alphabetical order): Pensoft Publishers.

M3 - doi:10.3897/zookeys.941.49100

Wikipedia/ Citizendium:

<ref name="Chiu2020ZooKeys941">{{Citation
| author = Chiu M, Huang C, Wu W, Lin Z, Chen H, Shiao S
| title = A new millipede-parasitizing horsehair worm, Gordius chiashanus sp. nov., at medium altitudes in Taiwan (Nematomorpha, Gordiida)
| journal = ZooKeys
| year = 2020
| volume = 941
| issue =
| pages = 25--48
| pmid =
| publisher = Pensoft Publishers
| doi = 10.3897/zookeys.941.49100
| url = https://zookeys.pensoft.net/articles.php?id=49100
| pmc =
| accessdate = 2020-10-20

}} Versioned wiki page: 2020-06-16, version 184077, https://species-id.net/w/index.php?title=Gordius_chiashanus&oldid=184077 , contributors (alphabetical order): Pensoft Publishers.</ref>

See also the citation download page at the journal.


Taxonavigation

Ordo: Gordea
Familia: Gordiidae
Genus: Gordius

Name

Gordius chiashanus Chiu sp. nov.Wikispecies linkZooBank linkPensoft Profile

Type locality

Dinghu (23°29'29.10"N, 120°43'19.00"E), Alishan township, Chiayi county, Taiwan (holotype). Paratypes were collected from Dasyueshan (Heping district, Taichung city), Xitou (Lugu township, Nantou county), Shihjhuo, Fenqihu (Zhuqi township, Chiayi county), Dinghu (Alishan township, Chiayi county), and Hongshi forest road (Haituan township, Taitung county). Table 1 presents detailed information of the locality.

Type material

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 1).

Table 1. Gordius chiashanus sp. nov. specimen information.
Collection date GenBank no. Locality Longitude and latitude Collector Depository Sex Status Length (mm)
20-XI-2017 MN784831 1 Dasyueshan (Heping, Taichung, Taiwan) 24°14'47.90"N, 120°56'06.80"E Ta-Chih Chen NMNS M Free-living adult 430
26-XI-2008 MN784832 Hongshi trail (Haituan, Taitung, Taiwan) 23°04'14.50"N, 121°07'58.30"E Po-Yen Chen NMNS M Free-living adult 744
22-I-2008 MN784841 Shihjhuo (Zhuqi, Chiayi, Taiwan) 23°29'01.70"N, 120°42'05.90"E Yu-Hsuan Tsai NMNS M Free-living adult 860
9-II-2007 MN784833 Shihjhuo (Zhuqi, Chiayi, Taiwan) 23°29'01.70"N, 120°42'05.90"E Yu-Hsuan Tsai NMNS F Free-living adult 707
8-XII-2017 MN784819 Dinghu (Alishan, Chiayi, Taiwan) 23°29'29.10"N, 120°43'19.00"E Ming-Chung Chiu LBM M Free-living adult 771
8-XII-2017 MN784820 Dinghu (Alishan, Chiayi, Taiwan) 23°29'29.10"N, 120°43'19.00"E Ming-Chung Chiu NMNS M Free-living adult 734
8-XII-2017 MN784821 Dinghu (Alishan, Chiayi, Taiwan) 23°29'29.10"N, 120°43'19.00"E Ming-Chung Chiu NMNS M Free-living adult 726
17-XII-2013 MN784822 Fenqihu (Zhuqi, Chiayi, Taiwan) 23°30'12.70"N, 120°41'36.00"E Hua-Te Fang LBM M Free-living adult 803
17-XII-2013 MN784823 Fenqihu (Zhuqi, Chiayi, Taiwan) 23°30'12.70"N, 120°41'36.00"E Hua-Te Fang LBM M Free-living adult 756
17-XII-2013 MN784824 Fenqihu (Zhuqi, Chiayi, Taiwan) 23°30'12.70"N, 120°41'36.00"E Hua-Te Fang NMNS M Free-living adult 594
17-XII-2013 MN784825 Fenqihu (Zhuqi, Chiayi, Taiwan) 23°30'12.70"N, 120°41'36.00"E Hua-Te Fang NMNS M Free-living adult 383
17-XII-2013 MN784826 Fenqihu (Zhuqi, Chiayi, Taiwan) 23°30'12.70"N, 120°41'36.00"E Hua-Te Fang NMNS M Free-living adult 676
17-XII-2013 MN784827 Fenqihu (Zhuqi, Chiayi, Taiwan) 23°30'12.70"N, 120°41'36.00"E Hua-Te Fang NMNS M Free-living adult 474
18-XII-2017 MN784828 Fenqihu (Zhuqi, Chiayi, Taiwan) 23°30'12.70"N, 120°41'36.00"E Ming-Chung Chiu NMNS M Free-living adult 749
18-XII-2017 MN784829 Fenqihu (Zhuqi, Chiayi, Taiwan) 23°30'12.70"N, 120°41'36.00"E Ming-Chung Chiu NMNS F Free-living adult 666
18-XII-2017 MN784830 Fenqihu (Zhuqi, Chiayi, Taiwan) 23°30'12.70"N, 120°41'36.00"E Ming-Chung Chiu NMNS F Free-living adult 717
18-XII-2016 MN784816 Xitou (Lugu, Nantou, Taiwan) 23°40'21.30"N, 120°47'27.50"E Ming-Chung Chiu LBM M Free-living adult 498
18-XII-2016 MN784817 Xitou (Lugu, Nantou, Taiwan) 23°40'21.30"N, 120°47'27.50"E Ming-Chung Chiu NMNS M Free-living adult 403
18-XII-2016 MN784818 Xitou (Lugu, Nantou, Taiwan) 23°40'21.30"N, 120°47'27.50"E Ming-Chung Chiu LBM F Free-living adult 549
9-II-2008 MN784842 Xitou (Lugu, Nantou, Taiwan) 23°40'21.30"N, 120°47'27.50"E Ming-Chung Chiu NMNS M Free-living adult 572
10-XII-2011 MN784840 Xitou (Lugu, Nantou, Taiwan) 23°40'21.30"N, 120°47'27.50"E Ming-Chung Chiu NMNS M Free-living adult 502
17-III-2019 MN784839 Xitou (Lugu, Nantou, Taiwan) 23°40'21.30"N, 120°47'27.50"E Zhao-Hui Lin NMNS - Dead worm in host -
23-VII-2018 MN784834 Shihjhuo (Zhuqi, Chiayi, Taiwan) 23°29'01.70"N, 120°42'05.90"E Yu-Wei Li NMNS - Immature worm 660
28-VII-2018 MN784835 Shihjhuo (Zhuqi, Chiayi, Taiwan) 23°28'22.60"N, 120°41'42.80"E Yu-Wei Li NMNS - Immature worm 894
28-VII-2018 MN784836 Shihjhuo (Zhuqi, Chiayi, Taiwan) 23°28'22.60"N, 120°41'42.80"E Yu-Wei Li NMNS - Immature worm 420
28-VII-2018 MN784837 Shihjhuo (Zhuqi, Chiayi, Taiwan) 23°28'22.60"N, 120°41'42.80"E Yu-Wei Li NMNS - Immature worm 442
28-VII-2018 MN784838 Shihjhuo (Zhuqi, Chiayi, Taiwan) 23°28'22.60"N, 120°41'42.80"E Yu-Wei Li NMNS - Immature worm 426

Type hosts

Spirobolus sp. nov. (Hsu and Chang, unpublished) (Diplopoda: Spirobolidae) (Fig. 5E, F)

Etymology

The specific name is the combination of chia, referring to the place (Chiayi county) where the first sample was found, and shan, referring to the Chinese word for “mountains.” The word chia is also in memory of our friend, Chia-Chih Lin, who died in an accident in a field experiment.

Description

Male adults (N = 11) (Figs 1–3, 5). Body length 627.94 ± 154.75 (383–860) mm, width (widest, after dehydration) 1.30 ± 0.31 (0.81–2.06) mm, light to dark brown, smooth, and covered with mucus-like structure (viscous liquid on live worms with rainbow-like reflection (Fig. 5C, Suppl. material 1: Video S1), and created haze that surrounded the body surface in hot water (Fig. 5A). 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. 1A). Under SEM, surface of anterior end appeared smooth (Fig. 1B) or wrinkled (Fig. 1C) on the tip of one sample; scattered short bristles (11.24 ± 6.57 (4.92–22.24) µm in length) scattered except on tip in most samples (Fig. 1B, D).
Cuticle in mid-body ornamented with a dorsal and a ventral dark pigment line; white spots scattered across entire body surface (Figs 3C, D, 5A). Under SEM, cuticle surface appeared smooth (Fig. 3A) with a few scattered short or cone-like bristles (6.75 ± 2.37 (2.31–10.34) µm in length) (Fig. 3A, B).
Posterior end divided into two tail lobes (Fig. 2A, B), each lobe 855.24 ± 100.89 (658.39–994.88) µm long and 458.55 ± 76.52 (365.95–643.00) µm wide with length-to-width ratio of 1.89 ± 0.26 (1.49–2.42). Inner side of lobe tips white (Fig. 2A). Under SEM, inner side of tail lobes concave in some samples; cuticle surface smooth, but one sample exhibited flat areoles on inner side of lobe tips; short bristles scattered across the surface and concentrated in most samples on lobe tips (Fig. 2C) and on inner side of lobe tips forming a bristle field (322.67 ± 99.34 (187.60–412.75) µm long and 71.82 ± 35.49 (44.81–114.54) µm wide) on each of tail lobe posterior to tips of postcloacal crescent (Fig. 2D). Postcloacal crescent (Fig. 2A, B) 718.61 ± 118.77 (536.14–984.34) µm long and 86.7 ±15.62 (54.73–118.65) µm wide and located on ventral side near base of tail lobes. Crescent generally semicircular or slightly angled, but a few samples exhibited a straightened form of crescent. Branches of postcloacal crescent usually ended at tail lobes. Cloacal opening circular (40.5 ± 21.87 (27.41–56.14) µm) and anterior to postcloacal crescent (Fig. 2A, B). Wall inside cloacal opening exhibited areoles (Fig. 2E); no circumcloacal spine or bristles observed in region next to cloacal opening. Female adults (N = 4) (Figs 4, 5). Body length 659.75 ± 77.06 (549–717) mm, width (widest, after dehydration) 1.54 ± 0.54 (1.00–2.03) mm, light to dark brown, smooth, and covered with mucus-like structure. White spots scattered on surface but relatively less obvious than those of male adults (Fig. 4F, G). Anterior end columnar and spherical. Anterior tip white (white cap) with a dark-brown collar and exhibited a vertical white stripe on the ventral side (Fig. 4A). Under SEM, surface of anterior end smooth and exhibited scattered short bristles (16.75 ± 4.60 (13.39–23.56) µm in length) except at tip (Fig. 4B). Cuticle in mid-body ornamented with a dorsal and a ventral dark pigment line (Fig. 4G). Under SEM, cuticle surface smooth with a few short or cone-like bristles (7.24 ± 2.01 (4.94–9.99) µm in length) scattered. Posterior end columnar and rounded at tip (Fig. 4E) and did not exhibit scattered bristles (Fig. 4D). Cloacal opening on terminal end (Fig. 4C, D) circular and 36.56 ± 23.23 (24.68–48.45) µm in diameter. Eggs (N = 12) (Fig. 6C–E). Egg strings (Fig. 6E) 7.41 ± 3.46 (3.78–13.70) mm in length and 1.13 ± 0.12 (0.86–1.25) mm in width; white or light yellow in color, deposited in water as short pieces not adhering to substrate. Eggs round, 54.16 ± 242 2.89 (49.88–58.61) µm in diameter. Developing embryo surrounded by an inner membrane (Fig. 6C, D) separated by a distinct space from outer egg shell 14.35 ± 1.41 (12.43–17.33) µm).
Living larvae (N = 10) (Fig. 6B). Eggs developed for approximately 49 days. Hatched larvae remained near egg strings or moved inside eggshells. Under light microscopy, living larvae appeared cylindrical with a single posterior spine. Preseptum length 32.33 ± 4.53 (27.06–40.04) µm, and the width 18.04 ± 0.86 (16.70–19.12) µm. Postseptum length 83.05 ± 8.31 (66.50–92.66) µm, width 15.05 ± 0.73 (14.21–16.10) µm; proboscis length 14.94 ± 1.99 (12.35–18.48) µm, width 4.11 ± 0.85 (2.77–5.34) µm; pseudointestine length 60.60 ± 5.40 (54.99–70.12) µm, width 11.66 ± 1.42 (8.84–13.56) µm, unequally subdivided, elongated oval with a depression in anterior end (Fig. 6B).
Larvae treated with hot water (N = 2) (Fig. 6A). Larvae treated with hot water similar in morphology but larger than living larvae. Preseptum length 44.57 ± 0.13 (44.48–44.66) µm, width 17.96 ± 0.16 (17.85–18.08) µm. Postseptum length 118.23 ± 1.91 (116.88–119.58) µm, width 15.36 ± 0.68 (14.88–15.84) µm. Proboscis length 12.63 ± 1.18 (11.80–13.47) µm, width 3.26 ± 0.05 (3.23–3.30) µm; pseudointestine length 77.99 ± 5.22 (74.30–81.68) µm, width 13.99 ± 0.81 (13.41–14.56) µm (Fig. 6A).
Field-collected cysts (N = 5) (Fig. 6F–H) . Larvae in cysts unfolded (N = 4) (Fig. 6F) or exhibited a postseptum folded twice (N = 1) (Fig. 6G, H). Unfolded larvae morphologically similar to larvae but larger in size; preseptum length was 60.18 ± 6.72 (50.40–65.18) µm, width 20.87 ± 0.52 (20.28–21.33) µm; postseptum length 127.33 ± 20.05 (105.10–146.05) µm, width 19.82 ± 2.27 (17.61–22.91) µm; proboscis length 15.46 ± 1.67 (13.84–17.56) µm, width 4.10 ± 0.68 (3.09–4.52) µm; pseudointestine not visible (Fig. 6F). Folded larva (length 34.97 µm, width 30.47 µm) fold twice and surrounded by a clear cyst wall, 47.86 µm in total length and 42.40 µm in total width; proboscis length 15.57 µm, width 5.09 µm (Fig. 6G); a single posterior spine visible after treatment with a solution of 5% KOH (Fig. 6H).

Table 2. List of COI sequences obtained from GenBank for phylogenetic analyses in this study.
Accession number Species/clade Reference
Gordius/Acutogordius
KM382317 G. cf. robustus (Clade 8) Hanelt et al. 2015[1]
KM382316 ‘’ Hanelt et al. 2015[1]
KM382315 ‘’ Hanelt et al. 2015[1]
KM382314 ‘’ Hanelt et al. 2015[1]
KM382313 ‘’ Hanelt et al. 2015[1]
KM382312 ‘’ Hanelt et al. 2015[1]
KM382311 ‘’ Hanelt et al. 2015[1]
KM382310 G. terrestris Hanelt et al. 2015[1], Anaya et al. 2019[2]
KM382309 ‘’ Hanelt et al. 2015[1], Anaya et al. 2019[2]
KM382308 ‘’ Hanelt et al. 2015[1], Anaya et al. 2019[2]
KM382307 ‘’ Hanelt et al. 2015[1], Anaya et al. 2019[2]
KM382306 G. cf. robustus (Clade 6) Hanelt et al. 2015[1]
KM382305 ‘’ Hanelt et al. 2015[1]
KM382304 ‘’ Hanelt et al. 2015[1]
KM382303 ‘’ Hanelt et al. 2015[1]
KM382302 ‘’ Hanelt et al. 2015[1]
KM382301 ‘’ Hanelt et al. 2015[1]
KM382300 ‘’ Hanelt et al. 2015[1]
KM382299 ‘’ Hanelt et al. 2015[1]
KM382297 G. cf. robustus (Clade 5) Hanelt et al. 2015[1]
KM382296 ‘’ Hanelt et al. 2015[1]
KM382295 ‘’ Hanelt et al. 2015[1]
KM382294 G. cf. robustus (Clade 4) Hanelt et al. 2015[1]
KM382293 ‘’ Hanelt et al. 2015[1]
KM382292 ‘’ Hanelt et al. 2015[1]
KM382291 ‘’ Hanelt et al. 2015[1]
KM382290 ‘’ Hanelt et al. 2015[1]
KM382289 G. cf. robustus (Clade 3) Hanelt et al. 2015[1]
KM382288 ‘’ Hanelt et al. 2015[1]
KM382287 ‘’ Hanelt et al. 2015[1]
KM382286 ‘’ Hanelt et al. 2015[1]
KM382285 ‘’ Hanelt et al. 2015[1]
KM382284 ‘’ Hanelt et al. 2015[1]
KM382283 G. cf. robustus (Clade 2) Hanelt et al. 2015[1]
KM382282 ‘’ Hanelt et al. 2015[1]
KM382281 G. cf. robustus (Clade 1) Hanelt et al. 2015[1]
KM382280 ‘’ Hanelt et al. 2015[1]
KM382279 ‘’ Hanelt et al. 2015[1]
KM382278 ‘’ Hanelt et al. 2015[1]
KM382277 ‘’ Hanelt et al. 2015[1]
KM382318 G. attoni Hanelt et al. 2015[1]
KM382319 ‘’ Hanelt et al. 2015[1]
KM382320 G. balticus Hanelt et al. 2015[1]
KM382321 Gordius sp. N178 Hanelt et al. 2015[1]
KM382322 Gordius sp. N183 Hanelt et al. 2015[1]
KM382323 Gordius sp. N297B Hanelt et al. 2015[1]
KM382324 Gordius sp. N357 Hanelt et al. 2015[1]
AB647235 Gordius sp. KW-2011-A Sato et al. 2012[3]
AB647237 Gordius sp. KW-2011-B Sato et al. 2012[3]
AB647241 Gordius sp. KW-2011-D Sato et al. 2012[3]
KY172751 Gordius sp. Tobias et al. 2017[4] Tobias et al. 2017[4]
KY172750 ‘’ Tobias et al. 2017[4]
KY172752 ‘’ Tobias et al. 2017[4]
KY172759 ‘’ Tobias et al. 2017[4]
KY172765 ‘’ Tobias et al. 2017[4]
KY172770* ‘’ Tobias et al. 2017[4]
KY172777 ‘’ Tobias et al. 2017[4]
KY172749 ‘’ Tobias et al. 2017[4]
KY172792 ‘’ Tobias et al. 2017[4]
KY172789 ‘’ Tobias et al. 2017[4]
KY172791 ‘’ Tobias et al. 2017[4]
KY172799 ‘’ Tobias et al. 2017[4]
KY172801 ‘’ Tobias et al. 2017[4]
KY172802 ‘’ Tobias et al. 2017[4]
KY172804 ‘’ Tobias et al. 2017[4]
KY172753 G. paranensis (Clade2) Tobias et al. 2017[4]
KY172754 ‘’ Tobias et al. 2017[4]
KY172755 ‘’ Tobias et al. 2017[4]
KY172756 ‘’ Tobias et al. 2017[4]
KY172776 ‘’ Tobias et al. 2017[4]
KY172782 ‘’ Tobias et al. 2017[4]
KY172813 ‘’ Tobias et al. 2017[4]
KY172811 G. paranensis (Clade1) Tobias et al. 2017[4]
KY172812 ‘’ Tobias et al. 2017[4]
KX591948 Acutogordius taiwanensis Chiu et al. 2017[5]
KX591947 ‘’ Chiu et al. 2017[5]
KX591946 ‘’ Chiu et al. 2017[5]
KX591945 ‘’ Chiu et al. 2017[5]
KX591944 ‘’ Chiu et al. 2017[5]
KX591943 ‘’ Chiu et al. 2017[5]
KX591942 ‘’ Chiu et al. 2017[5]
KX591941 ‘’ Chiu et al. 2017[5]
KX591940 ‘’ Chiu et al. 2017[5]
KX591939 ‘’ Chiu et al. 2017[5]
KX591938 ‘’ Chiu et al. 2017[5]
KX591937 ‘’ Chiu et al. 2017[5]
KX591936 ‘’ Chiu et al. 2017[5]
KX591935 ‘’ Chiu et al. 2017[5]
KX591934 ‘’ Chiu et al. 2017[5]
KX591933 ‘’ Chiu et al. 2017[5]
KX591932 ‘’ Chiu et al. 2017[5]
KX591931 ‘’ Chiu et al. 2017[5]
KX591930 ‘’ Chiu et al. 2017[5]
KX591929 ‘’ Chiu et al. 2017[5]
KX591928 ‘’ Chiu et al. 2017[5]
KX591927 ‘’ Chiu et al. 2017[5]
KX591926 ‘’ Chiu et al. 2017[5]
KX591925 ‘’ Chiu et al. 2017[5]
KX591924 ‘’ Chiu et al. 2017[5]
KX591923 ‘’ Chiu et al. 2017[5]
KX591922 ‘’ Chiu et al. 2017[5]
MF983649 Myanmar nematomorph
Out group
HM044105 Chordodes formosanus Chiu et al. 2011[6]
HM044124 ‘’ Chiu et al. 2011[6]
KY172780 Euchordodes nigromaculatus Tobias et al. 2017[4]
KY172803 ‘’ Tobias et al. 2017[4]
KY172747 Parachordodes diblastus Tobias et al. 2017[4]
KY172778 ‘’ Tobias et al. 2017[4]

Phylogeny

The partial COI sequences of the 18 free-living adults contained 15 haplotypes with 392 invariable sites, nine singletons, and 21 parsimoniously informative sites. The genetic distance among them was 0.0024 within the range of 0.0000–0.0510. The three living adults and six worms inside the hosts were considered conspecific with the 18 free-living adults because of their small genetic distances (0.0000–0.0719). The mean interspecific genetic distances between Gordius chiashanus sp. nov. and other Gordius species or clades were in the range of 0.2320–0.4242, and that between Gordius chiashanus sp. nov. and Acutogordius taiwanensis was 0.3648 (Table 3). In addition to short genetic distances, the conspecific status of the 18 free-living adults was also supported because all the samples were located in a single clade, as indicated by a high bootstrap value. No subgroup was detected because the polytomic topology exhibited low bootstrap values and short genetic distances. The Gordius species/clades in the present result were consistent with the results of Hanelt et al. (2015)[1] and Tobias et al. (2017)[4], despite slight differences in the relative relationships among species, which might be attributable to the differences in models used or the shorter sequence adopted in previous studies. The clade of A. taiwanensis was located within that of the Gordius species, and it did not behave as a sister group (Fig. 7).

Reproductive season

Free-living adult worms frequently aggregate and mate on wet ground (Fig. 5B, C) after rain or fog, and they are sometimes found in water or soil (Fig. 5D). They suddenly emerge in early December, and their number decreases within 1–2 months (Fig. 8). During the reproductive season, no infected host was found. The seasonality and pattern of Gordius chiashanus sp. nov. differed from the graph constructed using data from C. formosanus (Chiu et al. 2016[7]).

Diagnosis and comments

The 21 free-living Gordius adults and six juvenile worms from round-backed millipedes were judged as belonging to the same species in accordance with the results that they all were located in the same clade in the phylogenetic tree and had low genetic distances (Fig. 7, Table 3). These samples were regarded as a new species, Gordius chiashanus sp. nov., on the basis of their distribution patterns of bristles on the male tail and presence of a vertical white stripe on the anterior ventral side and areoles on the inside wall of the cloacal opening.

Table 3. Intra- and interspecific mean COI genetic distances of Gordius/Acutogordius species or clades under K2P model.
Species/Clade 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
1 Gordius chiashanus sp. nov. 0.024
2 G. cf. robustus (Clade1) 0.285 0.009
3 G. cf. robustus (Clade2) 0.312 0.217 0.015
4 G. cf. robustus (Clade3) 0.293 0.297 0.275 0.007
5 G. cf. robustus (Clade4) 0.308 0.208 0.249 0.157 0.012
6 G. cf. robustus (Clade5) 0.272 0.165 0.211 0.227 0.222 0.003
7 G. cf. robustus (Clade6) 0.293 0.257 0.251 0.255 0.228 0.259 0.006
8 G. terrestris 0.232 0.209 0.265 0.250 0.230 0.222 0.238 0.020
9 G. cf. robustus (Clade8) 0.265 0.203 0.307 0.338 0.253 0.244 0.251 0.122 0.026
10 G. attoni 0.277 0.229 0.288 0.337 0.274 0.238 0.289 0.231 0.249 0.010
11 G. balticus 0.316 0.260 0.298 0.288 0.269 0.274 0.304 0.264 0.323 0.337
12 Gordius sp. N178 0.352 0.260 0.313 0.370 0.289 0.340 0.330 0.256 0.290 0.271 0.323
13 Gordius sp. N183 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 Gordius sp. N297B 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 Gordius sp. N357 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 Gordius sp. KW-2011-A 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 Gordius sp. KW-2011-B 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 Gordius sp. KW-2011-D 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 G. paranensis (Clade1) 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 0.049
20 G. paranensis (Clade2) 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 0.010
21 Gordius sp. Tobias et al. 2017[4] 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 0.012
22 Acutogordius taiwanensis 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 0.002
The concentration of bristles and spines on the male tail lobes has been previously described in species from the Palaearctic (Spiridonov 1984[8]; Schmidt-Rhaesa 2010[9]) and Nearctic realms (Anaya et al. 2019[2]). In Gordius chiashanus sp. nov., this dense patch of bristles is a stable characteristic that was detected in all samples. The distribution pattern was similar to that of G. helveticus (Schmidt-Rhaesa 2010[9]) because the bristles exhibited a progressively broader distribution instead of being concentrated along the row of the ventral border, such as in G. karwendeli Schmidt-Rhaesa, 2010 (Schmidt-Rhaesa 2010[9]) and G. terrestris (Anaya et al. 2019[2]), or in a circular patch of concentrated spines, such as in G. spiridonovi Schmidt-Rhaesa, 2010 (Spiridonov 1984[8]).

Although the distribution pattern of the bristles is similar to that of G. helveticus, G chiashanus sp. nov. is morphologically distinct because of the presence of stout bristles on the mid-body, a vertical white stripe on the anterior ventral side, and areoles on the inside wall of the cloacal opening. The vertical white stripe on the anterior ventral side can be easily observed by the naked eye, but it has rarely been mentioned thus far. The presence of a white stripe was previously reported in the terrestrial hairworm, G. terrestris (Anaya et al. 2019[2]), which exhibits a broad white patch; however, the patch is likely to be the intensive aggregation of white spots in Gordius chiashanus sp. nov. The presence of areoles on the inside wall of the cloacal opening has only been reported in an unknown Gordius (Schmidt-Rhaesa 2012[10], fig. 3.2.2). Although cloacal openings are usually covered by contamination in many Gordius species, as was the case in most of our samples, the areole on the inside wall of cloacal opening might not be a general characteristic of the genus Gordius because it is absent in at least some species (e.g., G. serratus Schmidt-Rhaesa, 2010, G. terrestris, G. spiridonovi) (Schmidt-Rhaesa 2010[9]; Schmidt-Rhaesa and Prous 2010[11]; Anaya et al. 2019[2]).

Original Description

  • Chiu, M; Huang, C; Wu, W; Lin, Z; Chen, H; Shiao, S; 2020: A new millipede-parasitizing horsehair worm, Gordius chiashanus sp. nov., at medium altitudes in Taiwan (Nematomorpha, Gordiida) ZooKeys, 941: 25-48. doi

Images

Other References

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