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ZooKeys 320: 43–49, doi: 10.3897/zookeys.320.5147
A new species of Polypedilum (Uresipedilum) Oyewo & Sæther, 1998 from Zhejiang Province of Oriental China (Diptera, Chironomidae)
Xiaolong Lin 1,†, Xin Qi 2,‡, Ruilei Zhang 3,§, Xinhua Wang 1,|
1 College of Life Science, Nankai University, Tianjin 300071, China
2 College of Life Science, Taizhou University, Taizhou, Zhejiang 318000, China
3 College of Fisheries and Life Science, Shanghai Ocean University, Shanghai, 201306, China
† http://zoobank.org/AC3964DC-0709-4DCB-96AA-6EBEDFA04C07
‡ http://zoobank.org/C902B210-CE50-4C13-885B-CE172F2F633B
§ http://zoobank.org/779D0E50-116D-4C16-835B-6F2ABE0D1ED1
| http://zoobank.org/ACC3483B-5DD1-4F2D-88F7-1CE4C6458B68

Corresponding author: Xinhua Wang (xhwang@nankai.edu.cn)

Academic editor: V. Blagoderov

received 17 March 2013 | accepted 26 July 2013 | Published 31 July 2013


(C) 2013 Xiaolong Lin. This is an open access article distributed under the terms of the Creative Commons Attribution License 3.0 (CC-BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


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Citation: Lin X, Qi X, Zhang R, Wang X (2013) A new species of Polypedilum (Uresipedilum) Oyewo & Sæther, 1998 from Zhejiang Province of Oriental China (Diptera, Chironomidae). ZooKeys 320: 43–49. doi: 10.3897/zookeys.320.5147

Abstract

A new species of Polypedilum (Uresipedilum) Oyewo & Sæther, 1998, Polypedilum (Uresipedilum) minimum sp. n. is described as male. A key to adult males of the subgenus from China is presented.

Keywords

Chironomidae, Polypedilum (Uresipedilum) , key, new species, China

Introduction

Polypedilum is one of the largest chironomid genera containing about 440 described species. The larvae mostly occur in sediments, with a few species mining wood or grazing epilignic and epilithic surfaces (Cranston et al. 1989). At present, the genus Polypedilum comprises eight subgenera: Polypedilum Kieffer, 1912, Pentapedilum Kieffer, 1913, Kribionympha Kieffer, 1921, Tripedilum Kieffer, 1921, Tripodura Townes, 1945, Uresipedilum Oyewo & Sæther, 1998, Cerobregma Sæther & Sundal, 1999 and Probolum Andersen & Sæther 2010 (Sæther et al. 2010).

Sasa and Kikuchi (1995) proposed Uresipedilum for the Polypedilum convictum group sensu Niitsuma (1992), but they failed to designate the type species. Oyewo and Sæther (1998) validated the name by designating Polypedilum (Uresipedilum) convictum (Walker, 1856) as the type species. Zhang and Wang (2004) reviewed the subgenus on the basis of 14 species recorded in China. Sæther and Oyewo (2008) and Sæther et al. (2010) revised the subgenus around the world and transferred Polypedilum (Uresipedilum) bullum Zhang & Wang, 2004, Polypedilum (Uresipedilum) pedatum excelsius Townes, 1945 and Polypedilum (Uresipedilum) simantokeleum Sasa, Suzuki & Sakai, 1998 to the newly proposed subgenus Probolum. Up to date, Uresipedilum includes 46 known species.

The adult males of the subgenus Uresipedilum are separated from other subgenera by having the basal portion of the superior volsella much longer than wide, with an apicomedian projection without setae placed on the inner margin of the base and directed medially and without prominent inner projection; wing membrane without markings or setae and fore tibial scale nearly always without spur (Sæther et al. 2010).

Based on the material from Zhejiang Province of Oriental China, a new species is described and illustrated as male. A complemented key to adult males of Polypedilum (Uresipedilum) from China is presented.

Materials and methods

The morphological nomenclature follows Sæther (1980) and the abbreviations of structures measured follow Qi et al. (2012). The material examined was slide-mounted, following the procedure by Sæther (1969). The specimen examined in this study is deposited in the College of Life Science, Nankai University, China.

Taxonomy
Polypedilum (Uresipedilum) minimum sp. n.

http://zoobank.org/3237A70B-1254-4EB7-969B-6FD4ACC1883D

http://species-id.net/wiki/Polypedilum_minimum

Figures 1–7
Diagnosis.

The male adult can be distinguished from known species of the subgenus by the following combination of characters: low AR (0.27); frontal tubercles present; fore tibial scale rounded; anal point broad; superior volsella strongly projected posteriorly, pointed at apex, without microtrichium; high HV (4.90).

Description.

Male adult (n = 1). Total length 1.47 mm. Wing length 0.89 mm. Wing length/length of profemur 2.98.

Coloration. Head, legs and abdomen yellow. Thorax yellow with brown vittae, postnotum and preepisternum.

Head. AR 0.27. Antenna with 13 flagellomeres, ultimate flagellomere 93 μm long (Fig. 1). Frontal tubercles 38 μm long, 15 μm wide at base. Temporal setae 7, including 2 inner verticals, 4 outer verticals and 1 postorbital. Clypeus with 15 setae. Tentorium 70 μm long, 10 μm wide. Stipes 75 μm long, 10 μm wide. Palpomeres length (in μm): 18, 15, 38, 55, 103. L: 5th/3rd 2.73.

Figures 1–7.

Polypedilum (Uresipedilum) minimum sp. n. 1 Antenna. 2 Wing. 3 Thorax 4 Fore tibia scale 5 Dorsal view of hypopygium 6 Ventral view of hypopygium 7 Superior volsella.

Wing (Fig. 2). VR 1.54. Brachiolum with 1 seta, R with 11 setae, R1 with 6 setae, R4+5 with 15 setae. Squama with 6 setae.

Thorax (Fig. 3). Acrostichals 8; dorsocentrals 11; prealars 3. Scutellum with 4 setae.

Legs. Terminal scale (Fig. 4) of fore tibia rounded, 15 μm long, without spine. Spur of mid tibia 25 μm long, comb 10 μm long; unspurred comb 15 μm long. Spur of hind tibia 25 μm long, comb 10 μm long; unspurred comb 10 μm long. Apex of fore tibia 25 μm wide, of mid tibia 23 μm wide, of hind tibia 38 μm wide. Mid ta1 without sensilla chaetica. Lengths (in μm) and proportions of legs in Table 1.

Table 1.

Lengths (in μm) and proportions of legs of Polypedilum (Uresipedilum) minimum sp. n.

p1 p2 p3
fe 299 365 374
ti 215 251 308
ta1 317 165 194
ta2 143 75 120
ta3 115 60 115
ta4 85 38 65
ta5 40 38 50
LR 1.47 0.66 0.63
BV 2.17 3.70 2.50
SV 1.62 3.73 3.52
BR 3.60 4.33 5.14

Hypopygium (Figs 5–6). Tergite IX with 4 strong median setae. Laterosternite IX with 1 seta. Anal point broad, 18 μm long, with swollen, rounded apex. Phallapodeme 34 μm long; transverse sternapodeme 13 μm long. Gonocoxite 62 μm long, with 2 long setae. Superior volsella (Fig. 7) 16 μm long, with 3 basal inner setae and 1 strong apical seta, without microtrichium; apicomedial projection 17 μm long, pointed at apex. Inferior volsella 41 μm long, with 10 dorsal setae and 1 prominent apical seta. Gonostylus 30 μm long, apex blunt, with 3 setae along inner margin and 1 apical seta. HR 2.07. HV 4.90.

Type materials.

Holotype: adult male, China, Zhejiang Province: Jinhua City, Pan’an County, Dapanshan National Nature Reserve, 120.50°N, 29.00°E, 18.vii.2012, leg. Lin XL, sweep net.

Etymology.

From Latin minimum, little, referring to the small body length and antennal ratio.

Remarks.

The new species resembles Polypedilum (Uresipedilum) obtusum Townes, 1945, Polypedilum (Uresipedilum) aviceps Townes, 1945, Polypedilum (Uresipedilum) infundibulum Zhang & Wang, 2004, Polypedilum (Uresipedilum) surugense Niitsuma, 1992 and Polypedilum (Uresipedilum) paraviceps Niitsuma, 1992 in the general structure of hypopygium, but it can be separated by the superior volsella without microtrichium, which present in the latter species; the low antennal ratio (AR= 0.27), AR>1 in the latter species. The new species most resembles Polypedilum (Uresipedilum) breviplumosum Zhang & Wang, 2004 in the low antennal ratio (AR= 0.22–0.23), but it differs from the latter species by the following combination of characters in Table 2.

Table 2.

Differences between Polypedilum (Uresipedilum) minimum sp. n. and Polypedilum (Uresipedilum) breviplumosum Zhang & Wang, 2004

Polypedilum (Uresipedilum) minimum sp. n. Polypedilum (Uresipedilum) breviplumosum
TL 1.47 mm 2.24–2.57 mm
WL 0.89 mm 1.43–1.59 mm
Setae on squama 6 9–12
Anal point board slender
Superior volsella strongly projected posteriorly, bare, with 3 inner setae, pointed at apex rounded at apex, covered with microtrichia
Fore tibial scale rounded pointed
HR 2.07 1.25–1.40
HV 4.90 2.57–2.73

Female and immature stages unknown.

Key to adult males of Polypedilum (Uresipedilum) from China
1 Anal point semicircular 2
– Anal point triangular 5
2 Base of superior volsella without microtrichium 3
– Base of superior volsella with microtrichia 4
3 AR 1.25–1.48, superior volsella without inner seta Polypedilum (Uresipedilum) infundibulum Zhang & Wang, 2004
– AR 0.27, superior volsella with 3 inner setae Polypedilum (Uresipedilum) minimum sp. n.
4 Subapical tubercle of inferior volsella present Polypedilum (Uresipedilum) paraviceps Niitsuma, 1992
– Subapical tubercle of inferior volsella absent Polypedilum (Uresipedilum) surugense Niitsuma, 1992
5 AR about 0.2, frontal tubercles present Polypedilum (Uresipedilum) breviplumosum Zhang & Wang, 2004
– AR>0.8, frontal tubercles absent 6
6 Anal point with several lateral setae 7
– Anal point without lateral setae 8
7 Inner margin of superior volsella bulging Polypedilum (Uresipedilum) lateralum Zhang & Wang, 2004
– Inner margin of superior volsella medially constricted Polypedilum (Uresipedilum) dilatum Zhang & Wang, 2004
8 Inferior volsella with large ventral apical process Polypedilum (Uresipedilum) prominens Zhang & Wang, 2004
– Inferior volsella without large ventral apical process 9
9 Fore tibial scale rounded 10
– Fore tibial scale pointed 11
10 Base of superior volsella with 1–3 inner setae, projected posteriorly Polypedilum (Uresipedilum) convictum (Walker, 1856)
– Base of superior volsella with 4–5 inner setae, not projected posteriorly Polypedilum (Uresipedilum) crassiglobum Zhang & Wang, 2004
11 Base of superior volsella without seta Polypedilum (Uresipedilum) medium Zhang & Wang, 2004
– Base of superior volsella with several setae 12
12 Superior volsella with 2–5 apical setae Polypedilum (Uresipedilum) cultellatum Goetghebuer, 1931
– Superior volsella with 1 apical seta 13
13 Apicomedial projection of superior volsella much shorter than base Polypedilum (Uresipedilum) basilarum Zhang & Wang, 2004
– Apicomedial projection of superior volsella much longer than base Polypedilum (Uresipedilum) xuei Zhang & Wang, 2004
Acknowledgements

Financial support from the National Natural Science Foundation of China (NSFC, grant No. 31272284, 31201739, J1210005), the Zhejiang Provincial Natural Science Foundation of China (grant No. Y3100486), Fauna of China (FY120100) are acknowledged with thanks.

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