Research Article |
Corresponding author: Yufeng Yang ( tyyf@jnu.edu.cn ) Academic editor: Yasen Mutafchiev
© 2020 Yue Zeng, Nan Wei, Qing Wang, Nataliia S. Iakovenko, Ying Li, Yufeng Yang.
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:
Zeng Y, Wei N, Wang Q, Iakovenko NS, Li Y, Yang Y (2020) Bdelloid rotifers (Rotifera, Bdelloidea) of China: diversity and new records. ZooKeys 941: 1-23. https://doi.org/10.3897/zookeys.941.50465
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Bdelloid rotifers are a group of microscopic invertebrates known for their obligate parthenogenesis and exceptional resistance to extreme environments. Their diversity and distributions are poorly studied in Asia, especially in China. In order to better understand the species distribution and diversity of bdelloid rotifers in China, a scientific surveys of habitats was conducted with 61 samples (both terrestrial and aquatic habitats) from 11 provinces and regions of China, ranging from tropics to subtropics with a specific focus on poorly sampled areas (Oriental) during September 2017 to October 2018. A total of 59 morphospecies (including subspecies) were found, of which, thirty-nine morphospecies (including one genus) are new records for China, almost doubling the number of previous records. Four rare morphospecies (Adineta cf. acuticornis Haigh, A. beysunae Örstan, Habrotrocha ligula loxoglotta De Koning and H. serpens Donner) are depicted and redescribed, and an updated checklist of Chinese bdelloids with their location and ecological information is presented. This study provides new data from a large region of China, enriching the knowledge of bdelloid biodiversity, and their global biogeography.
bdelloids, biogeography, morphospecies, Oriental region, taxonomy
Bdelloid rotifers are microscopic invertebrates that constitute a subclass Bdelloidea of the phylum Rotifera, known for their peculiar obligate parthenogenesis (
Analysis of Bdelloidea taxonomy characteristics is problematic because only observation of living and active specimens allows appropriate identification of species. That is why it has not been widely carried out. Furthermore, there are no readily available reagents that can be used to anesthetize them and preserve their bodies fully extended (Örstan and Plewka 2017). Untill recently, only about 460 bdelloid species have been described worldwidely (
In China, only 48 bdelloid morphospecies have been reported (
Species | Habitats | EL (m) | WT (°C) | AT (°C) | pH | Distribution and references |
---|---|---|---|---|---|---|
Adineta gracilis Janson, 1893 | Moss | 800–1400 | – | – | – | GD (l) |
A. oculata (Milne, 1886) | Moss | 800–1800 | – | – | – | GD (l) |
A. vaga (Davis, 1873) | Moss and stream | 0–1750 m | 16–18 | 26–28 | 5 | GD (f, l), TB (g, h) |
Dissotrocha aculeata (Ehrenberg, 1832) | Pond, river and bog | 0–3650 | 20 | 20 | 6 | IM (b), HB, SD, ZJ, SC, XJ (e) TB (h), GD (l) |
D. macrostyla (Ehrenberg, 1832) | Pond and bog | 0–3030 | 17–20 | 13.5 | 6 | JS (d), TB (h), HA (i) |
D. macrostyla tuberculata (Gosse, 1886) | Puddle on the roadside | – | 20 | – | 7.6 | HA(k) |
Habrotrocha angusticollis angusticollis (Murray, 1905) | Sphagnum, river, lake branch channel and puddle with aquatic plant | 0–4750 | 14–30 | 21–25.5 | 6–8.5 | ZJ (e), TB (h), HA (i, k), GD (l) |
H. angusticollis attenuata (Murray, 1906) | Moss | – | – | – | – | GD (f) |
H. ampulla (Murray, 1911) | River with macrophyte | – | 20 | – | 6.32 | HA (i) |
H. collaris (Ehrenberg, 1832) | Bog, stream, lake and moss | 800–3800 | 12–19.5 | 15–25 | 6–7 | TB (h), GD (l) |
H. constricta (Dujardin, 1841) | – | – | – | – | – | HA (j) |
H. elegans (Milne, 1886) | Lake | 3658 | 13 | 15 | 7 | TB (h) |
*H. flexicollis Bartoš, 1963 | Moss | – | – | – | – | GD (f) |
H. fusca (Bryce, 1894) | Moss | – | – | – | – | GD (f) |
H. insignis Bryce, 1915 | Moss | – | – | – | – | GD (f) |
H. modesta Bartoš, 1963 | Moss | – | – | – | – | GD (f) |
H. munda Bryce,1913 | Bog | 4200 | 16.5 | 13.5 | 6 | TB (h) |
H. perforata (Murray, 1906) | Moss | – | – | – | – | GD (f) |
H. pulchra (Murray, 1905) | Spring with attachment from meadow, stone and soil, puddle from glacier | 5700 | 17 | 11 | 8 | TB (g, h) |
H. pusilla (Bryce, 1893) | Puddle from spring and wet moss on stone | 830–2400 | 30 | 25 | 6 | TB (h) |
H. thienemanni Hauer, 1924 | Puddle with aquatic plant and moss, glacier | 830–5550 | 13–30 | 15–25 | 5–7 | TB (g, h) |
H. tridens (Milne, 1886) | Moss | 600–1900 | – | – | – | GD (l) |
Otostephanos cf. donneri (Bartoš, 1959) | Aquatic ecosystem | – | – | – | – | YN (j) |
Macrotrachela bullata (Murray, 1906) | Stream with algae or moss | 1668–4150 | 10–18 | 19–28 | 5–6 | TB (g, h) |
M. ehrenbergii (Janson, 1893) | Moss | 4500 | – | – | – | TB (h) |
M. insolita De Koning, 1947 | Moss | 1000–1200 | – | – | – | GD (l) |
M. multispinosa Thompson, 1892 | Attachments on aquatic plants, bogs and moss from grass lands | 3300 | 16 | 17 | 6 | TB (h) |
M. musculosa (Miline, 1886) | Springs and wet moss | 4150–4500 | 6 | 11–19 | 6 | TB (h) |
M. plicata (Bryce, 1892) | Puddles | 4400–4500 | 12–14 | 10–14 | 7 | TB (h) |
M. papillosa Thompson, 1892 | Moss | – | – | – | – | GD (f) |
M. punctata (Murray, 1911) | Attachment from stone and wet grass | 3800–3850 | 12 | 19 | 7 | TB (h) |
M. quadrlcornlfera Milne, 1886 | Moss | 0–1900 | – | – | – | GD (l) |
Mniobia tentans Donner, 1949 | Stream with algae or moss | 1668–1750 | 16–18 | 25–28 | 5 | TB (g, h) |
Philodina citrina Ehrenberg, 1832 | Rice field, puddle, shallow and wet moss | 600–4350 | 12–27 | 10–28 | 6–7 | TB(c, h), GD (l) |
P. erythrophthalma Ehrenberg, 1830 | Pond, pool and stream with algae | 0–3370 | 9 | 12 | 7 | HB (e), TB (c, h) |
P. megalotrocha Ehrenberg, 1832 | Lake with macrophyte, pond, water reservoir and rice field | – | 20–26 | – | 6–8 | HB, SH, JS, ZJ (e) HA(i, k) |
P. nemoralis Bryce, 1903 | Rice field, bog and moss | 2000–2400 | 36 | 29 | 5 | TB (h) |
P. roseola Ehrenberg, 1832 | River, pond, marsh and moss | 0–3100 | – | – | – | IM (b) TB(c), HB, SH, JS, ZJ, HA (e) GD (l) |
P. vorax (Janson, 1893) | Stream, spring and puddle from river or glacier | 2400–5500 | 7–17 | – | 6–8 | TB (g, h) |
*Pleuretra similis Bartoš, 1963 | Moss | – | – | – | – | GD (f) |
Rotaria citrina (Ehrenberg, 1838) | Rice field and pool | 0–2400 | 13–28 | – | 6 | HB (e), TB (h) |
R. macroceros (Gosse, 1851) | Yangtze River, lake and moss | – | 25 | – | 6 | AH (a), HB (e), GD (l), HA(i, k) |
R. macrura (Ehrenberg, 1832) | River | – | – | – | – | IM (b) |
R. neptunia (Ehrenberg, 1830) | Pond, rice field and puddle | 0–3650 | 18–26 | – | 6–8.7 | AH (a), SH, JS, ZJ, HB, BJ, HL, LN, GS, HN, GD, GX, YN, SC (e), HA (i, k), TB (h) |
R. rotatoria (Pallas, 1766) | Pond and rice field | 0–830 | 20–26 | – | 6–8.7 | AH (a), IM (b), SH, HB (e), TB (h), HA (i, k) |
R. sordida (Western, 1893) | Moss; polluted lake | – | 21 | – | 7.1 | GD (f), HA(i, k) |
R. tardigrada (Ehrenberg,1830) | Lake, polluted river and puddle | 0–3658 | 18–25 | – | 6–7 | AH (a), HA (i, k), HL, SH, GS, JS (e) TB (h) |
R. tridens (Montet, 1915) | Bog, wet moss pool and attachment from stone | 2900–4550 | – | 15–18 | 6 | TB (c, h) |
A total of 61 samples was collected during the period from September 2017 to October 2018 in 11 provinces and regions of China across its subtropical and tropical zones at altitudes from 0–2850 m above sea level from four types of terrestrial habitat (soil, mosses, leaf litter and lichens) and four types of aquatic habitat (plankton, benthos, periphyton and dew) in fresh or brackish waters (Fig.
Locality codes | Locality | Sampling date | Habitat | GPS coordinates | Elevation (m) |
---|---|---|---|---|---|
GD1 | Chaozhou | 18.08.2017 | Moss on concrete | 23°58'15.13"N, 116°38'12.14"E | 1136 |
GD2 | Chaozhou | 18.08.2017 | Moss on bark | 23°58'14.93"N, 116°38'12.08E | 1139 |
GD3 | Chaozhou | 18.08.2017 | Moss on rock | 23°58'14.99"N, 116°38'12.11"E | 1138 |
GD4 | Chaozhou | 18.08.2017 | Moss on soil | 23°58'15.02"N, 116°38'12.09"E | 1138 |
GD5 | Chaozhou | 18.08.2017 | Moss on rock | 23°55'59.37"N, 116°36'59.84"E | 436 |
GD6 | Guangzhou | 05.11.2017 | Dry moss on bark | 23°06'35.11"N, 113°14'21.20"E | 10 |
GD7 | Guangzhou | 20.09.2017 | Lotus pond | 23°07'54.80"N, 113°20'39.44"E | 16 |
GD8 | Guangzhou | 05.11.2017 | Lotus pond | 23°07'54.80"N, 113°20'39.44"E | 16 |
GD9 | Guangzhou | 25.10.2018 | Lotus pond | 23°07'54.80"N, 113°20'39.44"E | 16 |
GD10 | Guangzhou | 11.06.2018 | Moss on concrete | 23°08'1.29"N, 113°20'38.81"E | 15 |
GD11 | Guangzhou | 11.06.2018 | Soil | 23°07'51.89"N, 113°20'37.45"E | 18 |
GD12 | Haiou island | 28.10.2017 | Water hyacinth root in brackish water | 22°58'23.36"N, 113°30'40.95"E | 4 |
GD13 | Guangzhou | 13.06.2018 | Bamboo leaf litter | 23°18'4.12"N, 113°26'23.21"E | 214 |
GD14 | Guangzhou | 13.06.2018 | Bamboo leaf litter | 23°18'18.99"N, 113°26'56.14"E | 152 |
GD15 | Guangzhou | 20.06.2017 | Bottom of lotic water | 23°18'0.59"N, 113°26'27.47"E | 226 |
GD16 | Guangzhou | 26.10.2018 | Urban river | 23°03'29.0"N, 113°24' 26.6"E | 0.75 |
GD17 | Nanao island | 22.04.2018 | Puddle | 23°25'44.88"N, 117°01'49.56"E | 108 |
GD18 | Nanao island | 09.01.2018 | Gracilaria lichenoides in brackish pond | 23°27‘18.13“N, 117°7'31.35"E | 170 |
GD19 | Nanao island | 22.04.2018 | Lotic water | 23°26'38.29"N, 117°05'22.94"E | 124 |
GD20 | Qingyuan | 12.05.2018 | Moss on concrete | 24°36'46.73"N, 112°35'57.02"E | 237 |
GD21 | Qingyuan | 12.05.2018 | Moss on concrete | 24°36'40.72"N, 112°35'50.11"E | 143 |
GD22 | Qingyuan | 12.05.2018 | Moss on soil | 24°36'40.44"N, 112°36'9.26"E | 142 |
GD23 | Qingyuan | 12.05.2018 | Moss on bark | 24°36'41.29"N, 112°36'9.26"E | 175 |
GD24 | Qiao island | 29.10.2017 | Bottom of brackish pool in mangrove | 23°27'32.41"N, 117°06'3.59"E | 53 |
GD25 | Nanao island | 18.11.2018 | Leaf litter | 22°25'42.45"N, 113°37'51.53"E | 137 |
GD26 | Nanao island | 18.11.2018 | Leaf litter | 23°27‘18.13“N, 117°7'31.35"E | 9 |
GS1 | Lanzhou | 07.06.2018 | Wet moss near pond | 36°08'25.56"N, 103°41'41.18"E | 1615 |
GZ1 | Guiyang | 24.08.2017 | Moss on rock | 26°36'1.75"N, 106°41'10.39"E | 1213 |
GZ2 | Guiyang | 24.08.2017 | Moss on rock | 26°05'52.74"N, 105°52'55.89"E | 1170 |
HN1 | Changde | 20.06.2017 | Moss on rock | 29°3'10.0"N, 111°40'13"E | 31 |
HN2 | Changde | 15.09.2017 | Moss on rock | 29°3'10.0"N, 111°40'13"E | 31 |
HN3 | Changde | 11.12.2017 | Moss on rock | 29°3'10.0"N, 111°40'13"E | 31 |
HN4 | Changde | 12.03.2018 | Moss on rock | 29°3'10.0"N, 111°40'13"E | 31 |
HN5 | Changde | 11.12.2017 | Aquatic plant | 29°02'23.49"N, 111°42'33.35"E | 35 |
HN6 | Changde | 12.12.2017 | Lemna minor in river | 29°7'20.0"N, 111°39'49"E | 57 |
HN7 | Changde | 15.09.2017 | Water sample from a pond | 29°3'10"N, 111°40'13.0"E | 30 |
HN8 | Changde | 12.03.2018 | Moss on soil | 29°03'13.78"N, 111°40'12.69"E | 31 |
HN9 | Changde | 11.12.2017 | Lotus pond | 29°03'3.68"N, 111°39'57.93"E | 35 |
JS1 | Nanjing | 15.08.2018 | Bamboo leaf litter | 32°3'28.63"N, 118°45'27.47"E | 39 |
JS2 | Nanjing | 15.08.2018 | Moss with leaf litter | 32°3'28.19"N, 118°45'24.52"E | 34 |
NX1 | Yinchuan | 02.07.2018 | Moss from dessert (32 °C of soil surface) | 38°33'45.38"N, 106°32'0.37"E | 1128 |
NX2 | Yinchuan | 01.07.2018 | Extremely dry Juniperus litter | 38°29'22"N, 106°12'1"E | 1109 |
QH1 | Qinghai lake | 09.06.2018 | Wet moss on bark | 36°47'46.11"N, 101°06'18.99"E | 2850 |
SC1 | Wawu mountain | 23.08.2017 | Wet moss on bark | 29°40'15.26"N, 102°56'53.92"E | 2105 |
SC2 | Wawu mountain | 23.08.2017 | Wet moss on bark | 29°40'10.36"N, 102°56'53.92"E | 2105 |
SC3 | Wawu mountain | 23.08.2017 | Wet moss on bark | 29°40'10.36"N, 102°56'53.92"E | 2100 |
SH1 | Chongming island | 29.12.2017 | Aquatic plants in brackish water | 31°31'9.5"N, 121°56'4.3"E | 3 |
SH2 | Chongming island | 29.12.2017 | Moss on soil in brackish marsh | 31°29'54"N, 121°55'20.7"E | 3 |
SH3 | Chongming island | 29.12.2017 | Reed root in brackish water | 31°30'43.9"N, 121°57'27.9"E | 3 |
SH4 | Chongming island | 29.12.2017 | Aquatic plants in brackish water | 31°31'2.9"N, 121°55'3.1"E | 2 |
YN1 | Kunming | 01.06.2018 | Moss on concrete | 25°3'20.5"N, 102°42'8.6"E | 1889 |
YN2 | Kunming | 01.06.2018 | Moss on soil | 25°3‘2.2"N, 102°42'5.1"E | 1908 |
YN3 | Kunming | 01.06.2018 | Moss on concrete | 25°3‘6.1"N, 102°42'5.41"E | 1900 |
YN4 | Kunming | 01.06.2018 | Lichens on bark | 25°8'0.2"N, 102°39'40.6"E | 1900 |
YN5 | Kunming | 01.06.2018 | Moss on rock | 24°57'59.4"N, 102°39'35"E | 1888 |
YN6 | Kunming | 11.10.2018 | Lichens on rock | 24°57'49.1"N, 102°37'44.6"E | 2150 |
YN7 | Kunming | 11.10.2018 | Leaf litter | 24°57'53.2"N, 102°37'44.6"E | 2143 |
YN8 | Kunming | 11.10.2018 | Dew on leaves | 24°57'55.5"N, 102°37'44.3"E | 2136 |
ZJ1 | Hangzhou | 19.11.2017 | Dry moss on Torreya grandis’ bark | 30°21'42.0"N, 119°34'28"E | 305 |
ZJ2 | Ningbo | 03.11.2018 | Bamboo leaf litter, | 29°52'40.3"N, 121°33'15.55"E | 37 |
ZJ3 | Zhoushan | 03.11.2018 | Leaf litter | – | – |
Based on the definition of boundary between the Palearctic and Oriental biogeographic regions in China (
Samples from terrestrial habitats were placed into firmly closed paper envelopes, then dried at room temperature and stored in the envelopes for several weeks or months. Planktonic samples were obtained by filtering 1 to 5 liters of water through a plankton net with a mesh size 30 µm. Benthic ones were collected by scraping the bottom of water bodies with a 500 ml plastic bottle. Periphytic rotifers were obtained by shaking or scraping aquatic plants, then preserved in plastic bottles.
Samples from aquatic habitats were concentrated by a nylon net of 30 μm mesh size, then examined in lab immediately without fixating or anesthetization. Rotifers from mosses, lichens and leaf litter were extracted by washing the substrate with distilled water following the method of Peters (1993). Soil rotifers were extracted by the method of wet-sieving and centrifugation in a sugar gradient (Freckman 1993).
Rotifers isolated from waters were transferred into a Petri dish and sorted under a dark field dissecting microscope (SZX10, Olympus, Japan) with a magnification of 64×. Selected specimens were placed onto glass slides by using micropipettes, then examined alive under a microscope (BX51, Olympus, Japan) with magnification of ×200–400. All living specimens were recorded and photographed using a digital camera (Truechrome Metrics, China) with the software of TCapture. Photos and digital screenshots from videos were used for species identification and illustrations.
Species were identified by both external morphology and anatomy using the keys of
All rotifers were measured from screenshots of digital videos after
BW body width (when creeping)
CW corona width
FL foot length
FW foot width
HL head length
HW head width
MinNW minimal neck width
MxNW maximal neck width
NL neck length
TL total length
TrL trunk and rump length
RaL ramus length
RkW rake width
RL rump length
RW rump width
SL spur length
SSW spur pseudosegment width
TrW trophi width
Fifty-nine morphospecies (including three subspecies) were identified in this survey (Table
Bdelloid rotifers found in this study with their updated biogeographic distribution after
Species | Locality codes | Biogeographic regions |
---|---|---|
* Adineta cf. acuticornis Haigh, 1967 | GD6, YN5–6, SC2 | AUS, ORI# |
* A. barbata Janson, 1893 | GD10, 14, JS1, ZJ2 | AFR, ANT, AUS, NEA, NEO, PAL, ORI# |
* A. bartosi Wulfert, 1960 | GZ2 | PAL, ORI# |
* A. beysunae Örstan, 2018 | GD13–14, 25–26, YN7–8, JS1 | NEA, ORI# |
* A. cuneata Milne, 1916 | GD1–2, SC2, JS2, YN6–7 | AFR, AUS, NEA, PAL, ORI# |
A. gracilis Janson, 1893 | HN2, QH1, JS1 | AFR, ANT, AUS, NEA, ORI, PAL |
A. oculata (Milne, 1886) | GD7, YN3, HN1 | NEO, PAL, ORI# |
* A. ricciae Segers & Shiel, 2005 | GD23, HN4 | AUS, ORI# |
* A. steineri Bartoš, 1951 | GD13 | ANT, AUS, NEA, NEO, PAL, ORI# |
A. vaga (Davis, 1873) | GZ2, HN2–4, ZJ2, YN1,7, GD5,7,13–14, 20–21,23 | AFR, ANT, AUS, NEA, NEO, ORI, PAL |
Dissotrocha macrostyla (Ehrenberg, 1838) | HN6 | AFR, AUS, NEA, NEO, ORI, PAL |
* Habrotrocha bidens (Gosse, 1851) | ZJ1 | AFR, AUS, NEA, NEO, ORI, PAL |
* H. cf. spicula Bryce, 1913 | GD2 | AFR, AUS, ORI, PAL |
H. constricta (Dujardin, 1841) | HN2 | AFR, ANT, AUS, NEA, NEO, PAC, PAL, ORI# |
H. insignis Bryce, 1915 | GD3 | AUS, PAL, ORI# |
* H. ligula loxoglotta De Koning, 1947 | YN5 | PAL, ORI# |
* H. rosa Donner, 1949 | GD25 | AFR, AUS, NEA, NEO, PAL, ORI# |
* H. serpens Donner, 1949 | GD6 | AFR, AUS, PAL, ORI# |
* Otostephanos regalis Milne, 1916 | GD13 | AFR, PAL, ORI# |
* Scepanotrocha semitecta Donner, 1951 | SC1 | NEO, PAL, ORI# |
Macrotrachela bullata (Murray, 1906) | GD3–4, GZ2 | AFR, ORI, PAL |
M. ehrenbergii (Janson, 1893) | HN7, GZ1 | AFR, AUS, NEA, NEO, ORI, PAC, PAL |
* M. habita (Bryce, 1894) | GD6, 11,20, 22–23, YN1–3, GZ1 | AFR, ANT, AUS, NEA, NEO, ORI, PAL |
* M. hewitti (Murray, 1911) | SH1 | AFR, PAL, ORI# |
* M. inermis Donner, 1965 | YN4 | PAL, ORI# |
M. insolita De Koning, 1947 | GD2, HN8 | ANT, AUS, NEA, NEO, PAL, ORI# |
* M. latior Doner, 1951 | YN7 | PAL, ORI# |
* M. libera Donner, 1949 | HN4 | PAL, ORI# |
M. multispinosa multispinosa Thompson, 1892 | GD6 | AFR, AUS, NEA, NEO, ORI, PAL |
* M. multispinosa brevispinosa (Murray, 1908) | YN5 | AFR, AUS, NEO, ORI, PAL |
* M. nana (Bryce, 1912) | QH1 | AFR, AUS, NEA, NEO, PAL |
M. plicata (Bryce, 1892) | SC2–3 | AFR, AUS, NEA, PAL, ORI# |
* M. quadricornifera quadricorniferoides De Koning, 1929 | JS1, 2 | AFR, ANT, NEO, ORI, PAL |
* M. quadricornifera scutellata Schulte, 1954 | GD13 | AUS, PAL, ORI# |
* M. timida Milne, 1916 | SC1–3, YN7 | AFR, AUS, PAL, ORI# |
* Philodina acuticornis Murray, 1902 | GD20–21, JS1, ZJ2 | AFR, AUS, NEA, NEO, PAL, ORI# |
* P. cf. indica Murray, 1906 | YN4 | NEA, PAL, ORI# |
* P. cf. proterva Milne, 1916 | GD5, YN1, 6, ZJ2 | AFR, AUS, NEA, PAL, ORI# |
* P. childi Milne, 1916 | GD14, YN7 | PAL, ORI# |
* P. duplicalcar (De Koning, 1947) | NX2 | PAL |
P. megalotrocha Ehrenberg, 1832 | HN5–6, 9, GD9, 12 | AFR, AUS, NEA, NEO, ORI, PAL |
* P. cf. parvicalcar De Koning, 1947 | SH2, GD25 | PAL, ORI# |
* P. plena (Bryce, 1894) | QH1, YN7 | AFR, ANT, AUS, NEA, NEO, PAL, ORI# |
* P. rapida Milne, 1916 | YN7 | AFR, NEO, PAL, ORI# |
P. roseola Ehrenberg, 1832 | GD19 | AFR, AUS, NEA, NEO, PAL, ORI# |
* P. rugosa Bryce, 1903 | GD20–21 | AFR, AUS, NEA, NEO, PAL, ORI# |
* P. tenuicalcar De Koning, 1947 | NX1 | PAL |
* P. tranquilla Wulfert, 1942 | HN2, GS1 | AUS, PAL, ORI# |
P. vorax (Janson, 1893) | HN2 | AFR, AUS, NEA, NEO, ORI, PAL |
* Pleuretra africana Murray, 1911 | YN2, 6 | AFR, NEO, ORI# |
* P. brycei (Weber, 1898) | GD15, 23 | AFR, AUS, NEA, NEO, PAL, ORI# |
Rotaria citrina (Ehrenberg, 1838) | GD16 | AFR, AUS, NEA, PAL, ORI# |
* R. laticeps Wulfert, 1942 | GD15, 24 | AUS, PAL, ORI# |
R. neptunia Ehrenberg, 1830 | GD16–17 | AFR, AUS, NEA, NEO, ORI, PAL |
* R. neptunoida Harring, 1913 | GD16–17, 19 | AFR, AUS, NEA, ORI, PAL |
R. rotatoria (Pallas, 1766) | HN5, GD8, 18, SH1, 3 | AFR, AUS, NEA, NEO, ORI, PAL |
R. sordida (Western, 1893) | HN2, 8, YN2–3, GD13–14,26, JS1 | AFR, AUS, NEA, NEO, ORI, PAL |
R. tardigrada (Ehrenberg, 1830) | HN9 | AFR, AUS, NEA, NEO, ORI, PAL |
R. tridens (Montet, 1915) | HN6, 9, GD9, 12 | AUS, NEA, NEO, PAL, ORI# |
During our survey, five collected bdelloids have a general resemblance to known species, but also showed some dissimilar traits from previously described taxa, and they were qualified with ‘cf.’ and await further analysis. One of these doubtful species, reported as H. cf. spicula Bryce, which showed a upturned dorsal protrusion. Philodina cf. indica Murray, P. cf. proterva Milne and P. cf. parvicalcar showed relative wide range of variations in their head proportion, which need further analyses.
Among these new records, some species are very rare, and few were first found out of their type localities or habitats, e.g., Adineta beysunae Örstan and Habrotrocha ligula loxoglotta De Koning; some new morphological characteristics were observed and need to be added to the original descriptions, e.g., Adineta cf. acuticornis Haigh and Habrotrocha serpens Donner, which are redescribed and illustrated in the next section.
Species richness of bdelliods recorded between 1908 and 2018 in different provinces of China is presented in Figure
Phylum Rotifera Cuvier, 1817
Class Eurotatoria De Ridder, 1957
Order Adinetida Melone & Ricci, 1995
Family Adinetidae Melone & Ricci, 1995
Genus Adineta Hudson & Gosse, 1886
Eight specimens found in mosses and two specimens found in lichens, from tropical (GD 6) and subtropical (YN 5–6, SC 2) zones (Table
Body transparent and colorless, with smooth skin. No eyespots. Rostrum rather long when animal creeps and stretches out, distal rostral pseudosegment semi-circular and flattened. Rostral lamella divided into two broad sickles-like lobes, immobile, laterally elongated, no trace of cilia under the present microscope image. Small oval head, HW 63–90% of HL and 11–16% of TL, HL 15–18% of TL. Five rectangular denticles in each rake.
Neck width not distinct from head and trunk. The width of the first two pseudosegments of neck approximately equal to HW, the second neck pseudosegment much wider and swollen than the first one. Antenna of two pseudosegments, with length 56–64% of the bearing pseudosegment width. Trunk oval, BW 15–22% of TL. Rump conical, TrL 54–67% of TL. The stomach lumen very narrow and Z-shaped (Fig.
Foot slim and short, of four pseudosegments. Spurs long, the inner edge of the spurs almost parallel to the straight outer edge for two-thirds of its length, then a small bulge followed by a contraction and tapers to a sharp point (Fig.
The detailed measurements are summarized in Table
Comparison the body dimensions of Adineta acuticornis between Chinese specimens and the original description.
Measurements | Chinese specimens | Original description |
TL | 166–266 (227±33) | 210 |
BW | 30–61 (44±10) | |
HL | 30–45 (40±5) | |
HW | 25–37 (30±4) | 30 |
NL | 15–34 (25±6) | |
MinNW | 16–31 (25±4) | |
MxNW | 22–42 (31±6) | |
RL | 20–44 (30±9) | |
RW | 22–38 (25±7) | |
FL | 21–32 (28±4) | |
FW | 11–16 (13±2) | |
SL | 11–13 (12±1) | 12 |
SSW | 6–8 (7±1) | 9 |
RaL | 9–12 (10±1) | |
TrW | 5–6 (5±1) | 7.5 |
Rake | 5–5 | |
TL/SL | 14.4–21.6 (18.3±3.4) | 17.5 |
TL/HW | 6.6–8.6 (7.5±0.8) | 7 |
Rostral lamella | immobile | immobile |
Antenna | 1/2 MNW | half neck width |
Foot segments | 4 | 4 |
Stomach lumen | one loop | two loops |
Habitats | lichen and moss | damp moss on soil |
Adineta acuticornis has not been found since its original description by
A distinct characteristic differentiating this morphospecies from Adineta vaga Davis is its wide and rostral lamellae which are slightly wider than the anterior head, while the rostral lamellae of A. vaga are narrower than the anterior head. It differs from Adineta glauca Wulfert by its spur shape, which is short and has a flat base, while A. glauca spur with a swollen base. This morphospecies differs from Adineta longicornis Murray by its spur shape which has bulge, while A. longicornis spur is slender and acute (
The general morphology of the Chinese specimen conforms to the description of the New Zealand population, except the position of the spur contraction is closer to the tip (the contraction is in the middle of the spur in Haigh’s description) and the stomach lumen do not have distinct two loops as Haigh’s description. A comparison with
Numerous specimens found in leaf litter from three provinces (GD13–14, 25–26, YN7, JS1) across tropical and subtropical zones. One specimen found in dew on leaves from Southwest of China (YN8) (Table
Body angulate, large and transparent. Sometimes the organs in the trunk show brown coloration. No eyespots. Rostral lamella flat and widened, with two lateral triangular auricular protrusions holding long rostral setae under them (the number of stiff under each could not be counted under microscope). Setae length varies from 11 to 30 μm. Head trapezoid, rather large and long, HW 80–110% of HLb, HLb 17–22% of TL, HW 13–20% of TL. Numbers of U-gaps denticles on rakes: 9–9 (N = 3), 10–10 (N = 4).
Neck distinct from head, the first two pseudosegments of neck narrower than HW. Trunk oval. Posterior end of the first rump pseudosegment with a pair of lateral angular knobs.
Foot of five pseudosegments with two pairs of lateral knobs on its first two pseudosegments, FL 14–22% of TL. Spurs long and sturdy, with short interspace, SL 6–8% of TL, 172–284% of SSW. Three short unsegmented toes. Ventral toe longer than two dorsal toes. Dental formula 2/2.
TL 289±40 μm, HLb 49±5 μm, HW 45±4 μm, FL 49±8 μm, SL 20±1 μm, SSW 10±1 μm, RkW (N = 2, with 9–9 denticles; N = 4, with 10–10 denticles) 21±1 μm, RaL (N = 14) 15.9±2 μm, TrW 7.3±1 μm.
This is the second report of this morphospecies since its original description by
Family Habrotrochidae Harring, 1913
Genus Habrotrocha Ehrenberg, 1838
Five specimens found in mosses on rock from Southwest China (YN5) (Table
Body slender and transparent, integument smooth. Rostrum long and strongly bent ventrally. Rostral lamellae divided into two semi-circular lobes and wider than the anterior rim of rostrum. Head similar to hexagon, HW 89% of HL. Corona slightly narrower than collar, with papillae clearly seen in the middle of each trochus, CW 97% of HW. Trochal discs separated by a narrow, V-shaped sulcus, in which a cylindrical ligula bends obliquely to the dorsal side (Fig.
Trunk slender and cylindrical, TrL 59–67% of TL. Rump conical, with both pseudosegments somewhat swollen and strong arched up dorsally and roofing the foot, the posterior rim of the second pseudosegment creased, RL 8–10% of TL.
Foot short with three pseudosegments, FL 6–8% of TL. Bulbous spurs short and triangular shape, with distinct tips and wide interspace, base swollen. The width of interspace 114% of SL, 97% of the swollen width. Three stout unsegmented toes of the same length. Trophi small, dental formula 3/3.
TL 186±43 μm, NL 27±3 μm, TrL 119±37 μm, RL 156±2 μm, RW 22±7, FL 12±2 μm, SL 4±2 μm, RaL 13±1 μm, TrW 5.6±0.5 μm.
Habrotrocha ligula loxoglotta was originally described from Holland (De Koning 1947), later reported from beech-oak needle-litter in Germany, from dry mosses in France (
Five specimens found in dry mosses on bark from southern China (GD6) (Table
Body extremely slender (BW is only about 6% of TL), long and cylindrical, integument transparent and smooth. Rostrum rather long, with two pseudosegments. The first pseudosegment circular and slightly bigger than the second one which often contracted (Fig.
Neck slender. Throat very short, pharyngeal tube long, undulating before the mastax. Dorsal antenna slender, with two segments, its length 86% of the antennal pseudosegment width. Trunk slender, the two lateral sides of trunk almost parallel when animal fully extended, the last trunk segment often strongly contracted. Rump conical, with both pseudosegments swollen, arched up dorsally and roofing the foot, RL 12% of TL.
Foot very short, of four pseudosegments, FL 5% of TL. Spurs triangular and have swollen base, each with curved inner margins and a very small interspace. SL 63% of SSW. Three short unsegmented and of approximately equal length toes (Fig.
The detailed measurements are summarized in Table
Comparison the body dimensions of Habrotrocha serpens between Chinese specimens and the original description from
Measurements | Chinese specimens |
|
|
TL | 213 | 193–273 | 200 |
BW | 18.7 | 17 | |
HL | 42 | ||
HW | 18.4 | ||
CW | 19.7 | ||
NL | 31.2 | ||
MinNW | 17.8 | ||
MxNW | 19.2 | ||
RL | 26.6 | ||
RW | 20 | ||
FL | 12 | ||
FW | 9.9 | ||
SL | 3.4 | ||
SSW | 5.4 | ||
RaL | 14 | 12.7 | 14.8 |
TrW | 5.9 | ||
TL/BW | 11.4 | 11.8 |
The general morphology of our sample conforms with the description of the Austrian population except that the rostrum is not always fully expanded to/exceeding the upper lip in a feeding position. It may because of the second pseudosegment of rostrum often contracted. Additionally, we observed three approximately equal-lengthed toes which were not clear in
This morphospecies was first described from soil from Austria by
Only 48 species were recorded in eleven studies conducted in China between 1908 and 2018 (Table
Due to a lack of insufficient taxonomic and diversity research in China, species richness is extremely uneven in different provinces of China. More morphospecies were recorded in the Tibetan Plateau (27 morphospecies) and Guangdong Province (22 morphospecies) with more samples collected (
The high dispersal potential of bdelloids has supposedly led to their generally cosmopolitan distribution (
With study extending to more ecological habitats, some morphospecies were found in a broader range of habitats. We observed five brackish water morphospecies: Rotaria rotatoria Pallas, R. laticeps Wulfert, R. tridens Montet, Philodina megalotrocha Ehrenberg and Macrotrachela hewitti Murray. They were found among aquatic plants or brackish temporary puddle with sediment in mangrove. Noticeably, R. rotatoria was abundant and dominated in Gracilaria lichenoides (a red alga) culture ponds, possibly because G. lichenoides could provide suitable habitats. These ecological differences seem to represent different ecological niches, which may hide some interesting phenomena of separated evolutionary lineages. For example, Adineta vaga, which occurs in the multiple types of habitats, has a large amount of cryptic diversity (
More than half of the recorded morphospecies from this study (some presumed cosmopolitan) are new records for the Oriental region as well as for South Asia. As there are still considerable gaps in faunistic studies in the Oriental region, we do not yet have sufficient faunistic data to determine the true distributions of bdelloids. Our findings highlight the need for further taxonomic studies on bdelloids in Asia. Furthermore, asexual bdelloids have evolved independently in spite of being effectively sympatric, indicating that they may adapt to different ecological niches, thus the type of habitat is a key player for microscopic species diversity and evolution (Birky et al. 2005). Applications of molecular phylogeny for identification of bdelloid species would be invaluable in uncovering the actual systematic status of some euryoecious or variable morphospecies so that we may better understand the true distribution of bdelloid species.
We gratefully acknowledge Prof. Larry Liddle (Long Island University, USA), Dr. Xuejia He (Research Center for Harmful Algae and Aquatic Environment, Jinan University), Dr. Thomas Mesaglio (University of New South Wale, Australia), Dr. Xiao Ma (South China Sea Institute of Oceanology, Chinese Academy of Sciences) and Prof. Zhili He (University of Oklahoma) for their comments on the manuscript and the linguistic help. We also thank Dr. Zhiwei Liu (Jinan University) for helping on the map of the sampling localities. This research was supported by National Natural Science Foundation of China (41673080, 31601840).