Research Article |
Corresponding author: Qiong Zhou ( hainan@mail.hzau.edu.cn ) Academic editor: Alan Myers
© 2022 Kui Zhang, Jun Wang, Yihao Ge, Jishun Ma, Qiong Zhou.
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:
Zhang K, Wang J, Ge Y, Ma J, Zhou Q (2022) A new Gammarus species from Xinjiang Uygur Autonomous Region (China) with a key to Xinjiang freshwater gammarids (Crustacea, Amphipoda, Gammaridae). ZooKeys 1090: 129-147. https://doi.org/10.3897/zookeys.1090.78834
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A new species of the genus Gammarus Fabricius, 1775 is described and illustrated from Xinjiang Uygur Autonomous Region, China. Gammarus zhouqiongi sp. nov. is characterized by pereopods III–IV with long straight setae on posterior margins; inner ramus of uropod III more than twice as long as peduncle, reaching 0.7 times the length of outer ramus; inner ramus with plumose setae, and outer ramus with both plumose setae and long simple setae. Detailed morphological comparisons with related species are discussed. The K2P distances for each marker (CO1, 16S, 28S, and EF1α) of the new species differ from those of other Gammarus species in Xinjiang. Both phylogenetic trees based on separate (CO1, 16S, 28S, and EF1α) and combined (CO1+16S+28S+EF1α) markers show that the new species is an independent branch. A key to identify Gammarus species in Xinjiang is provided.
Amphipoda diversity, mitochondrial DNA, morphology, new species, nuclear DNA, taxonomy, Xinjiang
The genus Gammarus Fabricius, 1775 is distributed in Eurasia and North America, and is one of the genera with the highest species richness in freshwater amphipods (
During our field surveys in Xinjiang between 2012–2020, a new species was discovered based on morphological and molecular analyses. To further identify and understand the evolutionary origins of the new species, phylogenetic analyses of Gammarus in Xinjiang were performed. The distributions of endemic species of the genus Gammarus in Xinjiang are presented in Fig.
Distribution map of Gammarus species from Xinjiang (China). Type localities are shown for the species 1–8. 1 Gammarus brevipodus Hou & Li, 2004 2 G. zhouqiongi sp. nov. 3 G. decorosus Meng, Hou & Li, 2003 4 G. liuruiyui Zheng, Hou & Li, 2020 5 G. takesensis Hou & Li, 2004 6 G. tastiensis Hou, 2002 7 G. tianshan Zhao, Meng & Hou, 2017 8 G. simplex Zhao, Meng & Hou, 2017 (map data from GEBCO Compilation Group [2020]).
Specimens were collected from the streams and adjacent puddles with fine-meshed hand nets (500 μm). Samples were stored in 95% ethanol in the field, and then deposited at -80 °C for long-term preservation. Type specimens are lodged in the College of Fisheries, Huazhong Agricultural University, Wuhan (China).
All dissected appendages were examined and drawn using a Leica DM2500 compound microscope equipped with a drawing tube. The body length was measured from the base of the first antenna to the end of the telson while the specimens were kept straight. Terminology and taxonomic description referred to
We did not obtain samples of G. simplex during field surveys, and no relevant record was accessible in GenBank. Genomic DNA was extracted using the Animal Genomic DNA Kit (Tsingke Biotech, Beijing). K2P distances based on each marker were calculated in MEGA 6 (
Gene | Primer | Sequence (5'–3') | Reference |
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CO1 | LCO1490 | GGTCAACAAATCATAAAGATATTGG |
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HCO2198 | TAAACTTCAGGGTGACCAAAAAAT |
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LCO3 | TCNACHAAYCATAAAGAYATTGGTAC |
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16S | 16STf | GGTAWHYTRACYGTGCTAAG |
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16Sbr | CCGGTTTGAACTCAGATCATGT |
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28S | 28F | TTAGTAGGGGCGACCGAACAGGGAT |
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28R | GTCTTTCGCCCCTATGCCCAACTGA |
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EF1α | EF1αF | CACTACTGGTCATCTCATCTAC |
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EF1αR | ACTTCCAGGAGAGTCTCAAAC |
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We selected the best-fit models by Akaike information criterion (AICc) in PartitionFinder (
Taxon | Coordinates | CO1 | 16S | 28S | EF1α | Reference |
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Gammarus brevipodus | 43.28N, 84.28E | MW723045 | MW729654 | MW729697 | MW749858 | This study |
G. zhouqiongi1 | 46.76N, 84.42E | MW723044 | MW729651 | MW729694 | MW749855 | This study |
G. zhouqiongi2 | 48.08N, 86.35E | MW729649 | MW729692 | MW749853 | This study | |
G. decorosus | 43.80N, 87.60E | JF965875 | JF965684 | JF966031 |
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G. lacustris | 47.24N, 88.47E | MW717900 | MW729628 | MW729674 | MW749832 | This study |
G. liuruiyui | 40.88N, 78.19E | MK455899 | MK455898 |
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G. takesensis | 43.63N ,81.80E | MW723041 | MW729638 | MW729681 | MW749842 | This study |
G. tastiensis | 45.95N, 82.57E | MW723046 | MW729655 | MW729698 | MW749859 | This study |
G. tianshan | 43.1N, 81.1E | EF570327 | EF582873 | EF582971 |
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Jesogammarus debilis | 39.5N, 115.8E | EF570351 | EF582846 | EF582997 |
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J. hebeiensis | 40.4N, 115.9E | EF570352 | EF582847 | EF582998 |
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Rhipidogammarus rhipidiophorus | 40.28N, 9.63E | JF966114 |
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The values of K2P distances between Gammarus zhouqiongi sp. nov. and other Gammarus species in Xinjiang (G. simplex excluded) ranged between 16.6%–32.4% for CO1, 11.0%–39.3% for 16S, 1.2%–6.3% for 28S and 1.3%–9.6% for EF1α (Table
Species | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | ||
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CO1 (below diagonal)/16S (above diagonal) | 1 | Gammarus brevipodus | 0.393 | 0.281 | 0.321 | 0.336 | 0.329 | 0.343 | ||
2 | G. zhouqiongi1 | 0.324 | 0.248 | 0.239 | 0.110 | 0.144 | 0.210 | |||
3 | G. decorosus | 0.349 | 0.262 | 0.085 | 0.232 | 0.258 | 0.170 | |||
4 | G. lacustris | 0.389 | 0.297 | 0.215 | 0.231 | 0.282 | 0.196 | |||
5 | G. liuruiyui | 0.316 | 0.308 | 0.265 | 0.329 | |||||
6 | G. takesensis | 0.347 | 0.166 | 0.267 | 0.324 | 0.326 | 0.104 | 0.193 | ||
7 | G. tastiensis | 0.322 | 0.190 | 0.264 | 0.352 | 0.355 | 0.177 | 0.229 | ||
8 | G. tianshan | 0.359 | 0.288 | 0.301 | 0.327 | 0.316 | 0.313 | 0.282 | ||
28S (below diagonal)/EF1α (above diagonal) | 1 | G. brevipodus | 0.067 | 0.053 | 0.132 | 0.065 | 0.069 | 0.061 | ||
2 | G. zhouqiongi1 | 0.053 | 0.029 | 0.096 | 0.013 | 0.017 | 0.044 | |||
3 | G. decorosus | 0.044 | 0.037 | 0.098 | 0.031 | 0.031 | 0.022 | |||
4 | G. lacustris | 0.040 | 0.033 | 0.007 | 0.112 | 0.118 | 0.120 | |||
5 | G. liuruiyui | 0.053 | 0.063 | 0.052 | 0.051 | |||||
6 | G. takesensis | 0.058 | 0.017 | 0.042 | 0.038 | 0.071 | 0.011 | 0.039 | ||
7 | G. tastiensis | 0.049 | 0.012 | 0.039 | 0.033 | 0.066 | 0.014 | 0.042 | ||
8 | G. tianshan | 0.044 | 0.039 | 0.017 | 0.014 | 0.054 | 0.045 | 0.037 |
Gammarus pulex (Linnaeus, 1758).
Holotype : male (GAHBH-001), 14.9 mm, Habahe County (48.08°N, 86.35°E), altitude 528 m, Xinjiang Uygur Autonomous Region, China, October 16, 2020, collected by Kui Zhang. Paratypes: female (GAHBH-002), 12.3 mm; five males and three females (GAHBH003-010), same data as holotype. three males and two females (GAKLY001-005), Emin County (46.76°N, 84.42°E), altitude 991 m, Xinjiang Uygur Autonomous Region, China, July 12, 2015, collected by Jun Wang and Yihao Ge.
The specific name was to thank Professor Zhou for funding this study.
Peduncle articles IV–V of antenna II with clusters of short setae; merus to carpus of pereopod III with clusters of long setae that exceed the width of the underlying segment on posterior margins; epimeral plates III with subacute posterodistal corners; inner ramus of uropod III more than twice times as long as peduncle, reaching 0.7 times the length of outer ramus, both inner and outer margins of inner ramus and the inner margins of outer ramus with plumose setae, and outer margin of outer ramus with long simple setae.
(GAHBH-001), 14.9 mm.
Head. (Fig.
Gammarus zhouqiongi sp. nov., male holotype A head B antenna I C flagellar article of antenna I with aesthetasc D antenna II E calceoli of antenna II F upper lip G lower lip H left mandible I incisor and lacinia mobilis of right mandible J left maxilla I K distal part of palp article II of right maxilla I L maxilla II M maxilliped.
Antenna I (Fig.
Antenna II (Fig.
Upper lip (Fig.
Mandible (Fig.
Lower lip (Fig.
Maxilla I (Fig.
Maxilla II (Fig.
Maxilliped (Fig.
Pereon. Gnathopod I (Fig.
Gnathopod II (Fig.
Pereopod III (Fig.
Pereopod IV (Fig.
Pereopod V (Fig.
Pereopod VI (Fig.
Pereopod VII (Fig.
Coxal gills (Figs
Pleon. Epimeral plates (Fig.
Pleopods (Fig.
Urosome. Urosomites (Fig.
Uropods I–III (Fig.
Telson (Fig.
(GAHBH-002). 12.3 mm
Pereon
. Gnathopod I (Fig.
Gnathopod II (Fig.
Pereopods III–VII (Fig.
Gammarus zhouqiongi sp. nov., female paratype (GAHBH-002) A pereopod III B pereopod IV C pereopod V D pereopod VI E pereopod VII F oostegite of gnathopod II G oostegite of pereopod III H oostegite of pereopod IV I oostegite of pereopod V J dactylus of pereopod III K dactylus of pereopod IV L dactylus of pereopod V M dactylus of pereopod VI N dactylus of pereopod VII.
Oostegite (Fig.
Urosome
. Uropods I–III (Fig.
Telson (Fig.
This species was collected from streams and the adjacent small puddles, usually under big rocks.
The new species Gammarus zhouqiongi sp. nov. is similar to G. takesensis in pereopods III and IV with straight setae on posterior margin; epimeral plates III with subacute posterodistal corners; and inner ramus of uropod III about 0.7 times as long as outer ramus. It differs from G. takesensis (G. takesensis in parentheses) by accessory flagellum of antenna I with five articles (four articles); inner and outer margins of inner ramus and the inner margins of outer ramus of uropod III with long plumose setae (short plumose setae); posterodistal corner of basis of pereopod VII with spines and setae (only with setae).
Gammarus zhouqiongi sp. nov. is also similar to G. tastiensis in peduncle articles IV–V of antenna II with short setae; pereopods III and IV with long and straight setae on posterior margin; both inner and outer margins of inner ramus and the inner margins of outer ramus of uropod III with plumose setae, and outer margin of outer ramus of uropod III with simple setae. It can be distinguished from G. tastiensis by the following characters (G. tastiensis in parentheses): inner ramus of uropod III more than 2 times as long as peduncle (inner ramus uropod III less than 2 times as long as peduncle); pereopods III–V are slender (strong).
A comparison between Gammarus species in Xinjiang is presented in the following key.
1 | Eyes present | 2 |
– | Eyes absent | Gammarus liuruiyui |
2 | Uropod III inner ramus less than 0.6 times the length of outer ramus | 3 |
– | Uropod III inner ramus more than 0.6 times the length of outer ramus | 5 |
3 | Pereopod III–IV posterior margins and uropod III bearing sparse setae | G. brevipodus |
– | Pereopod III–IV posterior margins and uropod III bearing normally distributed setae | 4 |
4 | Peduncle articles IV–V of antenna II with long setae and epimeral plate III with blunt posterodistal corner | G. simplex |
– | Peduncle articles IV–V of antenna II with short setae and epimeral plate III with subacute posterodistal corner | G. tianshan |
5 | Uropod III outer ramus with plumose setae | 6 |
– | Uropod III outer ramus with simple setae | 7 |
6 | Telson bearing short setae and epimeral plate III with acute posterodistal corner | G. lacustris |
– | Telson bearing long setae and epimeral plate III with blunt posterodistal corner | G. decorosus |
7 | Posterodistal corner of basis of pereopod VII with setae | G. takesensis |
– | Posterodistal corner of basis of pereopod VII with spines | 8 |
8 | Pereopod V–VII are slender and inner ramus uropod III more than twice as long as peduncle of uropod III | G. zhouqiongi sp. nov. |
– | Pereopod V–VII are strong and inner ramus uropod III less than twice as long as peduncle of uropod III | G. tastiensis |
This work was supported by the Special Funds for the Foundation Work of Science and Technology (2012FY112700) and the Finance Special Fund of the Ministry of Agriculture and Rural Affairs (Fisheries Resources and Environment Survey in the Key Water Areas of Northwest China). We would greatly thank Dr Lili Wei and Guang Zhao for field sampling and Dr Shiming Wan for help in laboratory analyses.