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Research Article
DNA barcoding for molecular identification of the genus Oxyscelio (Hymenoptera, Scelionidae) from southern China, with descriptions of five new species
expand article infoWen-hui Mo‡, Hua-yan Chen§, Hong Pang§, Jing-xian Liu|
‡ South China Agricultural University, Guangzhou, China
§ Sun Yat-sen University, Guangzhou, China
| South China Agricultural University, Guangdong, China

Corresponding author: Hua-yan Chen ( huayanc@scbg.ac.cn )

Academic editor: Elijah Talamas
© 2021 Wen-hui Mo, Hua-yan Chen, Hong Pang, Jing-xian Liu.
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: Mo W-h, Chen H-y, Pang H, Liu J-x (2021) DNA barcoding for molecular identification of the genus Oxyscelio (Hymenoptera, Scelionidae) from southern China, with descriptions of five new species. In: Lahey Z, Talamas E (Eds) Advances in the Systematics of Platygastroidea III. Journal of Hymenoptera Research 87: 613-633. https://doi.org/10.3897/jhr.87.71912
ZooBank: urn:lsid:zoobank.org:pub:CACE04D1-17FF-46DE-84CB-A8302CF3EE8E
Open Access

Abstract

Species of the genus Oxyscelio Kieffer are egg parasitoids of Orthoptera. The genus is relatively diverse in China, with 34 described species. Some species of the genus are extremely morphologically similar and difficult to identify, especially in males. In this study, DNA barcoding based on sequences of the COI gene was used to discriminate Oxyscelio species from southern China. In total, 49 COI sequences belonging to 22 morphospecies were obtained. The COI sequences worked well for the identification of all the studied species, with intraspecific genetic distances ranging between 0 and 4.3%, while interspecific distances ranged between 7.1% and 19%. Based on both morphological and molecular analyses, five species are described as new: O. amalocarina Mo & Chen, sp. nov., O. apheles Mo & Chen, sp. nov., O. latheticus Mo & Chen, sp. nov., O. stenos Mo & Chen, sp. nov., and O. striae Mo & Chen, sp. nov.

Keywords

Egg parasitoid, integrated taxonomy, molecular species delimitation, Platygastroidea

Introduction

Oxyscelio Kieffer is a large genus of parasitoids attacking the eggs of Orthoptera (Kononova and Fursov 2007), with 186 species having been described from the Indo-Malayan, Palearctic, Australian, Pacific and African regions (Burks et al. 2013a, 2013b, 2016; Mo et al. 2020). Species of the genus are easily recognized by the following combination of characters: submarginal vein of forewing distant from wing margin, marginal vein very short, postmarginal vein absent or very short, vertex rounded posteriorly, metascutellum distinct and usually excavate dorsally, and many species have a pronounced frontal depression on the head which is often rimmed by a carina (Burks et al. 2013a). However, some species within the genus are extremely similar morphologically and difficult to identify. In fact, some similar species were suspected to be the same species with different body sizes (Burks et al. 2013a). In addition, some males are even more difficult to separate and could not be associated with the females of the same species (Burks et al. 2013a). These issues could be tackled by DNA barcoding (the partial sequencing of the mitochondrial gene cytochrome c oxidase 1, COI), which has become an important species identification tool for insects (Hebert et al. 2003a, b). Recently, the Chinese Oxyscelio fauna has been reviewed by Mo et al. (2020) and 34 species were recorded, most of which occur in southern China. In this study, we aim to test the morphological species delimitation of Oxyscelio species from southern China using DNA barcoding methods.

Materials and methods

Insect sampling and identification

This work is based on specimens of Oxyscelio collected by sweep net and mostly Malaise traps (MT) set up in provinces of southern China. Specimens were identified using the keys of Mo et al. (2020). Abbreviations and morphological terms used in text: A1, A2, ... A12: antennomere 1, 2, … 12; T1, T2, ... T7: metasomal tergite 1, 2, ... 7; S1, S2, ... S7: metasomal sternite 1, 2, … 7. Morphological terminology otherwise generally follows Burks et al. (2013a) except two terms that are discussed below. The definition of epomial corner used by Burks et al. (2013a) was not clearly stated and refers to where the epomial carina meets the transverse pronotal carina. The corner is weak or strong as a result of the development of the anterior part of the transverse pronotal carina. Therefore, we here describe the development of the anterior part of the transverse pronotal carina instead of the epomial corner. Most Oxyscelio species usually have one carina on the middle of the gena, which was termed as ‘middle genal carina’ by Burks et al. (2013a). It seems that Burks et al. (2013a) referred this carina as ‘middle genal carina’ because they erroneously treated the ventral part of the occipital carina as ‘posterior genal carina’. Therefore, we here refer the carina or carinae present on the gena as genal carina or genal carinae.

All the studied specimens are deposited in the Museum of Biology at Sun Yat-sen University, Guangzhou, China (SYSBM). Multifocal images were made using a Nikon SMZ25 microscope with a Nikon DS-Ri 2 digital camera system. Images were then post-processed with Adobe Photoshop CS6 Extended.

DNA extraction, amplification, and sequencing

In total, 49 specimens of 22 morphospecies were used for DNA barcoding analysis (see Table 1). Both female and male specimens were selected for each species when such specimens were available. Genomic DNA was extracted from entire specimens using a DNeasy Blood & Tissue Kit (QIAGEN, Inc.), following a nondestructive DNA extraction protocol as described in Taekul et al. (2014). Following DNA extraction, the “barcode” region of the mitochondrial cytochrome oxidase subunit 1 (COI) was amplified using the LCO1490/HCO2198 primer pair (Folmer et al. 1994). Polymerase chain reactions (PCRs) were performed using Tks Gflex DNA Polymerase (Takara), and conducted in a T100 Thermal Cycler (Bio-Rad). Thermocycling conditions were: an initial denaturing step at 94 °C for 5 min, followed by 35 cycles of 94 °C for 30 s, 50 °C for 30 s, 72 °C for 30 s and an additional extension at 72 °C for 5 min. Amplicons were directly sequenced in both directions with forward and reverse primers on an Applied Biosystems (ABI) 3730XL by Guangzhou Tianyi Huiyuan Gene Technology Co., Ltd. (Guangzhou, China). Chromatograms were assembled with Geneious 11.0.3. All sequences generated from this study are deposited in GenBank (accession numbers see Table 1).

Table 1.
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List of sequenced taxa and accession numbers.

Code Species Sex Locality GenBank accession number
M205 O. amalocarina sp. nov. female Hunan, 29°56'N, 110°46'E MZ539945
M242 O. apheles sp. nov. female Yunnan, 21°44.49'N, 100°26.89'E MZ539946
M182 O. arcus female Hainan, 19°4'44.68"N, 109°24'4.74"E MZ539947
M194 O. arcus female Guangdong, 23°10'49.87"N, 113°21'21.33"E MZ539948
M201 O. arcus female Guangdong, 23°9'46.54"N, 112°32'42.9"E MZ539949
M271 O. arcus female Guangxi, 25°21'42.94"N, 110°22'49.9"E MZ539950
M212 O. brevidentis male Yunnan, 21°44.761'N, 100°25.959'E MZ539951
M213 O. brevidentis female Yunnan, 21°44.761'N, 100°25.959'E MZ539952
M241 O. brevidentis male Yunnan, 21°44.498'N, 100°26.889'E MZ539953
M190 O. convergens female Hainan, 19°10'23.28"N, 109°43'40.79"E MZ539954
M193 O. convergens male Hainan, 19°10'23.28"N, 109°43'40.79"E MZ539955
M195 O. convergens female Guangdong, 22°31'53.35"N, 114°36'4.1"E MZ539956
M197 O. convergens female Guangdong, 22°54'26.09"N, 114°13'13.47"E MZ539957
M198 O. convergens male Guangdong, 22°54'26.09"N, 114°13'13.47"E MZ539958
M203 O. convergens male Guangdong, 23°9'45.81"N, 112°32'42.2"E MZ539959
M204 O. convergens male Hainan, 19°4'20.77"N, 109°22'28.2"E MZ539960
M237 O. convergens female Zhejiang, 27°48'45"N, 119°50'28"E MZ539961
M238 O. convergens male Zhejiang, 27°48'45"N, 119°50'28"E MZ539962
M177 O. crebritas female Guangdong, 23°37.287'N, 113°51.267'E MZ539963
M186 O. crebritas female Hainan, 19°10'22.14"N, 109°43'10.34"E MZ539964
M199 O. crebritas male Guangdong, 22°54'26.09"N, 114°13'13.47"E MZ539965
M222 O. doumao female Yunnan, 21°44.745'N, 100°26.07'E MZ539966
M180 O. excavates male Hainan, 18°41'N, 108°49'E MZ539967
M220 O. granorum male Yunnan, 21°44.745'N, 100°26.07'E MZ539968
M223 O. granorum male Yunnan, 21°44.745'N, 100°26.07'E MZ539969
M226 O. granorum female Yunnan, 21°44.912'N, 100°26.647'E MZ539970
M268 O. intermedietas female Yunnan, 21°36'54"N, 101°35'2"E MZ539971
M269 O. jugi male Yunnan, 21°36'54"N, 101°35'2"E MZ539972
M233 O. kramatos female Guangdong, 24°43'N, 114°14'E MZ539973
M184 O. kiefferi female Hainan, 19°4'44.68"N, 109°24'4.74"E MZ539974
M210 O. labis female Yunan, 21°44.761'N, 100°25.959'E MZ539975
M211 O. labis male Yunan, 21°44.761'N, 100°25.959'E MZ539976
M225 O. labis male Yunnan, 21°45.061'N, 100°21.661'E MZ539977
M185 O. latinubbin female Hainan, 19°4'43.32"N, 109°23'38.74"E MZ539978
M206 O. latheticus sp. nov. female Hunan, 29°56'N, 110°46'E MZ539979
M232 O. latheticus sp. nov. female Guangdong, 24°43'N, 114°14'E MZ539980
M183 O. nubbin female Hainan, 19°4'44.68"N, 109°24'4.74"E MZ539981
M187 O. nubbin female Hainan, 19°10'22.14"N, 109°43'10.34"E MZ539982
M188 O. nubbin male Hainan, 19°10'22.14"N, 109°43'10.34"E MZ539983
M192 O. nubbin female Hainan, 19°30'56.91"N, 109°29'29.28"E MZ539984
M179 O. nullicarina male Hainan, 18°41'N, 108°49'E MZ539985
M231 O. nullicarina female Yunnan, 22°52'53.09"N, 104°5'50.98"E MZ539986
M216 O. ogive female Yunnan, 21°44.746'N, 100°26'E MZ539987
M219 O. ogive female Yunnan, 21°44.745'N, 100°26.07'E MZ539988
M239 O. stenos sp. nov. female Yunnan, 23°14'11.18"N, 104°6'3.44"E MZ539989
M215 O. striae sp. nov. female Yunnan, 21°44.746'N, 100°26'E MZ539990
M275 O. striae sp. nov. female Yunnan, 21°44.746'N, 100°26'E MZ539991
M278 O. striae sp. nov. female Yunnan, 21°44.746'N, 100°26'E MZ539992
M229 O. striarum female Yunnan, 21°91.613'N, 101°27.118'E MZ539993

Sequence analysis and molecular species delimitation

All sequences were blasted in BOLD (Barcode of Life Database, http://www.barcodinglife.org/index.php/IDS_OpenIdEngine) and GenBank. Sequences were aligned using MAFFT v7.470 by the G-INS-I strategy (Katoh and Standley 2013). Genetic Kimura-2 parameter (K2P) distances within and between species were calculated in MEGA 7 with pairwise deletion for gaps (Kumar et al. 2016). The aligned sequences were then analyzed using RAxML as implemented in Geneious 11.0.3 under the GTRGAMMA evolutionary model to generate a maximum likelihood (ML) tree. The COI sequences of Probaryconus rufipes (Kieffer, 1908) (MF583546) and Scelio striatus Priesner, 1951 (MF583556) (Hymenoptera, Scelionidae) were selected as outgroups based on the phylogenetic topologies recovered by Chen et al. (2021).

Results

This study generated 49 COI sequences with an average of 660 bp. Voucher specimens of these 49 sequences were subjected to further morphological examination and 22 species were recognized, of which five are described as new. There are only two COI sequences of Oxyscelio spp. in the BOLD and GenBank databases and the blast results of the sequences generated in this study returned no matching sequences. Genetic distances of the 49 sequences are in Suppl. material 1: Table S1. Intraspecific distances of the COI sequences generally are less than 3%, with two exceptions: O. crebritas and O. convergens. Oxyscelio crebritas has two haplogroups and the distance between the two haplogroups is 4.3%. Oxyscelio convergens also has two haplogroups and the distance between the two haplogroups is 3.9%. However, the two haplogroups of these two species are both clustered together on the ML tree (Figure 1), respectively. Interspecific distances range between 7.1% and 19%. Overall, the morphology-based delimitations of species are generally highly supported, as shown in Figure 1, indicating that DNA barcoding is well suited to help resolve species limits.

Figure 1. 

Maximum likelihood tree demonstrating the clustering of Oxyscelio COI barcodes. Bootstraps values of 50 and above are indicated.

Species treatment

Oxyscelio amalocarina Mo & Chen, sp. nov.

http://zoobank.org/B1EA6947-3B08-41B1-BDD5-3E21D7BB8A44
Figure 2

Description

Female. Body length 3.65 mm (n = 1).

Radicle color: same color as scape. Scape color: yellowish. A4: longer than broad. A5: longer than broad. Antennal club in female: formed, segments compact.

Figure 2. 

Oxyscelio amalocarina Mo & Chen, sp. nov., holotype, female (SCAU 3049046) A dorsal habitus B lateral habitus C head and mesosoma, dorsal view D head and mesosoma, lateral view E head, anterior view F antenna G metasoma, dorsal view H metasoma, ventral view.

Interantennal process: not elongate. Median longitudinal elevation in frontal depression: absent. Frontal depression: flat. Frontal depression sculpture: with 3–5 complete transverse carinae below submedian carina. Submedian carina: rather weak, only upper portion developed. Submedian carina medially: without peak. Concavity across dorsal part of frontal depression: absent. Depression extending ventrally from median ocellus: absent. Upper frons: not hood-like. Malar area near antennal foramen: without carina or expansion. Facial striae: present. Smooth strip along posterior side of malar sulcus: present, broad throughout its length. Genal carina: absent. Major sculpture of gena anteriorly: punctate. Major sculpture of gena posteriorly: rugose; punctate. Microsculpture of gena anteroventrally: absent. Microsculpture of gena posteroventrally: absent. Median carina extending posteriorly from hyperoccipital carina: absent. Hyperoccipital carina: indicated by rugae. Lateral connection between hyperoccipital and occipital carinae: absent. Area between vertex and occipital carina: foveate. Occipital carina medially: absent. Lateral corners of occipital carina: sharp and protruding.

Lateral pronotal area: without bulge projecting towards anterior pit. Transverse pronotal carina: absent anteriorly. Netrion surface anteriorly: not inflected. Mesoscutum anteriorly: steep. Mesoscutal median carina: present and complete. Longitudinal carina between median carina and notauli: absent. Major sculpture of medial mesoscutum anteriorly: foveate; rugose. Major sculpture of medial mesoscutum posteriorly: foveate. Microsculpture of medial mesoscutum anteriorly: granulate. Microsculpture of medial mesoscutum posteriorly: absent. Major sculpture of mesoscutellum: foveate. Microsculpture of mesoscutellum medially: absent. Microsculpture of mesoscutellum laterally: absent. Mesoscutellar apex: straight. Setae along anterior limit of femoral depression: arising from rows of foveae. Number of carinae crossing speculum above femoral depression: 3. Number of carinae crossing femoral depression: more than 5. Mesepimeral sulcus pits: more than 5. Metascutellum dorsally: concave. Metascutellar sculpture dorsally: areolate. Median carina of metascutellum: absent. Metascutellar setae: with many dorsal setae. Metascutellar apex: weakly emarginate. Metapleuron above ventral metapleural area: crossed by carinae. Metasomal depression setae: not visible. Lateral propodeal carinae anteromedially: strongly diverging. Anterior areoles of metasomal depression: not visible. Anterior longitudinal carinae in metasomal depression: not visible. Lateral propodeal areas: separated medially. Postmarginal vein: absent. Fore wing apex: reaching apex of T5.

T1 midlobe: obscured by other raised sculpture. T1: with anterior bulge. T2: with straight longitudinal striae. T6: longer than broad. Metasomal apex: rounded. Major sculpture of T6: punctate. Microsculpture of T6: absent. S2: with longitudinal rugae. S5: with longitudinal striae. S6: punctate.

Male. Unknown.

Diagnosis

Female: A4 and A5 longer than broad. Frontal depression flat. Submedian carina of frons weak, only upper portion developed. Gena without middle carina. Occipital carina absent medially. Metascutellum areolate, with many dorsal setae. T1 with anterior bulge. The above diagnostic characters make O. amalocarina unique and can be easily separated from other species of Oxyscelio.

Etymology

The name amalocarina refers to the weak submedian carina of this species. The epithet is used as a noun in apposition.

Material examined

Holotype , female: China: Hunan, Mt. Hupingshan, 29°56'N, 110°46'E, 9.VIII.2009, Ya-li Tang, SCAU 3049046 (deposited in SYSBM).

Distribution

China (Hunan).

The key to females of the Chinese Oxyscelio published by Mo et al. (2020) could be updated to accommodate O. amalocarina by replacing couplet 6 as follows

6 Mesosoma and metasoma black (Fig. 2A); mesoscutum foveate posteriorly (Fig. 2C) 6'
– Mesosoma and metasoma yellowish; mesoscutum transversely rugose posteriorly Oxyscelio nullicarina Mo & Chen
6' Upper frons not hood-like (Fig. 2E); T1 with anterior bulge (Fig. 2G) Oxyscelio amalocarina Mo & Chen, sp. nov.
– Upper frons hood-like; T1 without anterior bulge Oxyscelio doumao Burks

Oxyscelio apheles Mo & Chen, sp. nov.

http://zoobank.org/E44FFEC7-ABC5-46D1-B4A7-C4F9B264BDAC
Figure 3

Description

Female. Body length 3.08 mm (n = 1).

Radicle color: same color as scape. Scape color: dark brown. A4: as long as broad. A5: broader than long. Antennal club in female: formed, segments compact.

Figure 3. 

Oxyscelio apheles Mo & Chen, sp. nov., holotype, female (SCAU 3049046) A dorsal habitus B lateral habitus C head and mesosoma, dorsal view D head and mesosoma, lateral view E head, anterior view F Antenna G metasoma, dorsal view H metasoma, ventral view.

Interantennal process: not elongate. Median longitudinal elevation in frontal depression: absent. Frontal depression: concave. Frontal depression sculpture: with 3 broadly interrupted transverse carinae below submedian carina. Submedian carina: strong, formed by a sharp raised carina. Submedian carina medially: with sharp peak. Concavity across dorsal part of frontal depression: absent. Depression extending ventrally from median ocellus: absent. Upper frons: not hood-like. Malar area near antennal foramen: without carina or expansion. Facial striae: present. Smooth strip along posterior side of malar sulcus: absent or not consistently broad. Genal carina: present. Direction of genal carina dorsally: parallel to eye margin. Major sculpture of gena anteriorly: smooth with scattered punctures. Major sculpture of gena posteriorly: rugulose with scattered punctures. Microsculpture of gena anteroventrally: absent. Microsculpture of gena posteroventrally: absent. Median carina extending posteriorly from hyperoccipital carina: absent. Hyperoccipital carina: indicated by rugae. Lateral connection between hyperoccipital and occipital carinae: absent. Area between vertex and occipital carina: foveate. Occipital carina medially: uniformly rounded. Lateral corners of occipital carina: protruding.

Lateral pronotal area: without bulge projecting towards anterior pit. Transverse pronotal carina: present anteriorly and forming a corner with epomial carina. Netrion surface anteriorly: not inflected. Mesoscutum anteriorly: steep. Mesoscutal median carina: present and complete. Longitudinal carina between median carina and notauli: absent. Major sculpture of medial mesoscutum anteriorly: punctate. Major sculpture of medial mesoscutum posteriorly: punctate. Microsculpture of medial mesoscutum anteriorly: granulate. Microsculpture of medial mesoscutum posteriorly: absent. Major sculpture of mesoscutellum: punctate. Microsculpture of mesoscutellum medially: absent. Microsculpture of mesoscutellum laterally: absent. Mesoscutellar apex: convex or straight. Setae along anterior limit of femoral depression: arising from rows of foveae. Number of carinae crossing speculum above femoral depression: 3. Number of carinae crossing femoral depression: more than 5. Mesepimeral sulcus pits: more than 5. Metascutellum dorsally: concave. Metascutellar sculpture dorsally: smooth. Median carina of metascutellum: absent. Metascutellar setae: absent. Metascutellar apex: straight. Metapleuron above ventral metapleural area: crossed by carinae. Metasomal depression setae: absent. Lateral propodeal carinae anteromedially: weakly diverging. Anterior areoles of metasomal depression: absent. Anterior longitudinal carinae in metasomal depression: absent. Lateral propodeal areas: separated medially. Postmarginal vein: absent. Fore wing apex: reaching beyond T6.

T1 midlobe: with 6 longitudinal carinae. T1: without anterior bulge. T2: with straight longitudinal striae or rugae. T6: broader than long. Metasomal apex: rounded. Major sculpture of T6: punctate. Microsculpture of T6: absent. S2: with longitudinal rugae. S5: with longitudinal striae. S6: punctate rugose.

Male. Unknown.

Diagnosis

Female: A4 as long as broad, A5 broader than long. Frons without elevation between antennal foramen and eye. Upper frons not hood-like. Hyperoccipital carina indicated by rugae. Medial mesoscutum punctate posteriorly. Metascutellum without dorsal setae, mooth. T1 with 6 longitudinal carinae. Oxyscelio apheles is similar to O. vittae Burks but can be separated from the latter by the following characters: radicle, scape and coxae blackish, metapleuron above ventral metapleural area crossed by carinae.

Etymology

The name apheles refers to the smooth metascutellum of this species. The epithet is used as a noun in apposition.

Material examined

Holotype , female: China: Yunnan, Xishuangbanna, Menghai, Bulangshan Village, 1659 m, Area B1, forest, 21°44.498'N, 100°26.889'E, 28.VI–19.VII.2019, Li Ma, SCAU 3049083 (deposited in SYSBM).

Distribution

China (Yunnan).

The key to females of the Chinese Oxyscelio published by Mo et al. (2020) could be updated to accommodate O. apheles by replacing couplet 23 as follows

23 Genal carina strong, with two strong carinae below; postmarginal vein present Oxyscelio labis Burks
– Genal carina weakly indicated, without carinae below; postmarginal vein absent 23'
23' Submedian carina with sharp peak medially (Fig. 3E); radicle and scape dark brown (Fig. 3F) Oxyscelio apheles Mo & Chen, sp. nov.
– Submedian carina without sharp peak medially; radicle and scape yellowish Oxyscelio naraws Burks

Oxyscelio latheticus Mo & Chen, sp. nov.

http://zoobank.org/681C9A5A-7E92-42EA-B71B-9A9B5096D693
Figure 4

Description

Female. Body length 2.9–2.93 mm (n = 2).

Radicle color: same color as scape. Scape color: yellowish. A4: broader than long. A5: broader than long. Antennal club in female: formed, segments compact.

Figure 4. 

Oxyscelio latheticus Mo & Chen, sp. nov., holotype, female (SCAU 3049073) A dorsal habitus B lateral habitus C head and mesosoma, dorsal view D head and mesosoma, lateral view E head, anterior view F antenna G metasoma, dorsal view H metasoma, ventral view.

Interantennal process: not elongate. Median longitudinal elevation in frontal depression: absent. Frontal depression: concave. Frontal depression sculpture: with 3 broadly interrupted transverse carinae below submedian carina. Submedian carina: strong, formed by a sharp raised carina. Submedian carina medially: without peak. Concavity across dorsal part of frontal depression: absent. Depression extending ventrally from median ocellus: absent. Upper frons: hood-like. Malar area near antennal foramen: without carina or expansion. Facial striae: present. Smooth strip along posterior side of malar sulcus: absent or not consistently broad. Genal carina: present. Direction of genal carina dorsally: parallel to eye margin. Major sculpture of gena anteriorly: rugose; foveate. Major sculpture of gena posteriorly: rugose; foveate. Microsculpture of gena anteroventrally: absent. Microsculpture of gena posteroventrally: absent. Median carina extending posteriorly from hyperoccipital carina: present. Hyperoccipital carina: complete, extending ventrally around outer orbit of compound eye. Lateral connection between hyperoccipital and occipital carinae: absent. Area between vertex and occipital carina: irregularly rugose. Occipital carina medially: uniformly rounded. Lateral corners of occipital carina: not protruding.

Lateral pronotal area: without bulge projecting towards anterior pit. Transverse pronotal carina: present anteriorly and forming a corner with epomial carina. Netrion surface anteriorly: not inflected. Mesoscutum anteriorly: steep. Mesoscutal median carina: present and complete. Longitudinal carina between median carina and notauli: absent. Major sculpture of medial mesoscutum anteriorly: foveate; rugose. Major sculpture of medial mesoscutum posteriorly: foveate. Microsculpture of medial mesoscutum anteriorly: granulate. Microsculpture of medial mesoscutum posteriorly: granulate. Major sculpture of mesoscutellum: foveate; longitudinally rugose. Microsculpture of mesoscutellum medially: granulate. Microsculpture of mesoscutellum laterally: granulate. Mesoscutellar apex: convex or straight. Setae along anterior limit of femoral depression: arising from rows of foveae. Number of carinae crossing speculum above femoral depression: 4. Number of carinae crossing femoral depression: more than 5. Mesepimeral sulcus pits: more than 5. Metascutellum dorsally: concave. Metascutellar sculpture dorsally: foveate. Median carina of metascutellum: absent. Metascutellar setae: absent. Metascutellar apex: straight. Metapleuron above ventral metapleural area: crossed by carinae. Metasomal depression setae: absent. Lateral propodeal carinae anteromedially: strongly diverging. Anterior areoles of metasomal depression: absent. Anterior longitudinal carinae in metasomal depression: absent. Lateral propodeal areas: separated medially. Postmarginal vein: present. Fore wing apex: reaching beyond T6.

T1 midlobe: with 4 longitudinal carinae. T1: without anterior bulge. T2: with straight longitudinal striae. T6: broader than long. Metasomal apex: rounded. Major sculpture of T6: punctate. Microsculpture of T6: granulate. S2: with longitudinal rugae. S5: with longitudinal rugae. S6: punctate rugose.

Male. Unknown.

Diagnosis

Female: A4 and A5 broader than long. Frons without elevation between antennal foramen and eye. Hyperoccipital carina present, extending ventrally around outer orbit of compound eye. Medial mesoscutum foveate. Metascutellum without dorsal setae. T1 with 4 longitudinal carinae. Oxyscelio latheticus is extremely similar to O. convergens but can be distinguished from the latter by the following characters: A4 and A5 broader than long in O. latheticus (longer than broad in O. convergens); metascutellar apex straight and the lateral carina of metascutellum blunt, while in O. convergens, metascutellar apex emarginated and the lateral carina of metascutellum forming an acute tooth.

Etymology

The name latheticus refers to the fact that this species is extremely similar to O. convergens and could be overlooked. The epithet is used as a noun in apposition.

Material examined

Holotype , female: China: Guangdong, Mt. Chebaling, 24°43'N, 114°14'E, 22–28.II.2008, Zai-fu Xu, SCAU 3049073 (deposited in SYSBM). Paratype: Hunan, Mt. Hupingshan, 29°56'N 110°46'E, 9.VII.2009, Ya-li Tang, SCAU 3049047 (SYSBM)

Distribution

China (Hunan, Guangdong).

The key to females of the Chinese Oxyscelio published by Mo et al. (2020) could be updated to accommodate O. latheticus by replacing couplet 10 as follows

10 Mesosoma and metasoma yellowish 10'
– Mesosoma and metasoma entirely black 11
10' A5 broader than long (Fig. 4F); metascutellar apex straight and the lateral carina of metascutellum blunt (Fig. 4C) Oxyscelio latheticus Mo & Chen, sp. nov.
– A5 longer than broad; metascutellar apex emarginated and the lateral carina of metascutellum forming an acute tooth Oxyscelio convergens Burks

Oxyscelio stenos Mo & Chen, sp. nov.

http://zoobank.org/0CA2EB89-BE13-44FB-95D8-C9F5036BBA89
Figure 5

Description

Female. Body length 2.83 mm (n = 1).

Radicle color: darker than scape. Scape color: yellowish. A4: broader than long. A5: broader than long. Antennal club in female: formed, segments compact.

Figure 5. 

Oxyscelio stenos Mo & Chen, sp. nov., holotype, female (SCAU 3049080) A dorsal habitus B lateral habitus C head and mesosoma, dorsal view D head and mesosoma, lateral view E head, anterior view F antenna G metasoma, dorsal view H metasoma, ventral view.

Interantennal process: not elongate. Median longitudinal elevation in frontal depression: present. Frontal depression: concave. Frontal depression sculpture: with 3 broadly interrupted transverse carinae below submedian carina. Submedian carina: strong, formed by a sharp raised carina. Submedian carina medially: with sharp peak. Concavity across dorsal part of frontal depression: absent. Depression extending ventrally from median ocellus: absent. Upper frons: not hood-like. Malar area near antennal foramen: without carina or expansion. Facial striae: present. Smooth strip along posterior side of malar sulcus: absent or not consistently broad. Genal carina: present. Direction of genal carina dorsally: parallel to eye margin. Major sculpture of gena anteriorly: rugose; foveate. Major sculpture of gena posteriorly: rugose; foveate. Microsculpture of gena anteroventrally: absent. Microsculpture of gena posteroventrally: granulate. Median carina extending posteriorly from hyperoccipital carina: present. Hyperoccipital carina: complete, continuous with anterior genal carina. Lateral connection between hyperoccipital and occipital carinae: present. Area between vertex and occipital carina: irregularly rugose. Occipital carina medially: convex, with a sharp median peak. Lateral corners of occipital carina: sharp and protruding.

Lateral pronotal area: without bulge projecting towards anterior pit. Transverse pronotal carina: present anteriorly and forming a corner with epomial carina. Netrion surface anteriorly: not inflected. Mesoscutum anteriorly: steep. Mesoscutal median carina: present and complete. Longitudinal carina between median carina and notauli: absent. Major sculpture of medial mesoscutum anteriorly: punctate; rugose. Major sculpture of medial mesoscutum posteriorly: punctate. Microsculpture of medial mesoscutum anteriorly: granulate. Microsculpture of medial mesoscutum posteriorly: absent. Major sculpture of mesoscutellum: punctate; longitudinally rugose. Microsculpture of mesoscutellum medially: absent. Microsculpture of mesoscutellum laterally: absent. Mesoscutellar apex: straight. Setae along anterior limit of femoral depression: arising from rows of foveae. Number of carinae crossing speculum above femoral depression: 2. Number of carinae crossing femoral depression: more than 5. Mesepimeral sulcus pits: more than 5. Metascutellum dorsally: concave. Metascutellar sculpture dorsally: foveate. Median carina of metascutellum: absent. Metascutellar setae: absent. Metascutellar apex: straight. Metapleuron above ventral metapleural area: foveate. Metasomal depression setae: absent. Lateral propodeal carinae anteromedially: strongly diverging. Anterior areoles of metasomal depression: present. Anterior longitudinal carinae in metasomal depression: present. Lateral propodeal areas: separated medially. Postmarginal vein: absent. Fore wing apex: reaching beyond apex of T6.

T1 midlobe: with 4 longitudinal carinae. T1: without anterior bulge. T2: with straight longitudinal striae. T6: broader than long. Metasomal apex: rounded. Major sculpture of T6: punctate. Microsculpture of T6: absent. S2: with longitudinal rugae. S5: with longitudinal striae. S6: punctate.

Male. Unknown.

Diagnosis

Female: A4 and A5 broader than long. Frontal depression with median longitudinal elevation. Frons without elevation between antennal foramen and eye. Hyperoccipital carina present, extending ventrally around outer orbit of compound eye. Medial mesoscutum punctate. Metascutellum without dorsal setae. T1 with 4 longitudinal carinae. Oxyscelio stenos is similar to O. ogive and O. striae but can be separated from the latter two species by the narrow metascutellum and the median longitudinal elevation on frontal depression (see the updated key below).

Etymology

The name stenos refers to the narrow metascutellum of this species. The epithet is used as a noun in apposition.

Material examined

Holotype , female: China: Yunnan, Wenshan City, Pingba Town, 1793 m, 23.23644°N, 104.100955°E, 31.VIII-22.IX.2009, Malaise trap, SCAU 3049080 (deposited in SYSBM).

Distribution

China (Yunnan).

Oxyscelio striae Mo & Chen, sp. nov.

http://zoobank.org/D27BEA28-9CBF-49BD-8C06-1D80A5E28FFE
Figures 6

Description

Female. Body length 2.86–3.0 mm (n = 3).

Radicle color: darker than scape. Scape color: yellowish. A4: broader than long. A5: broader than long. Antennal club in female: formed, segments compact.

Figure 6. 

Oxyscelio striae Mo & Chen, sp. nov., holotype, female (SCAU 3048667) A dorsal habitus B lateral habitus C head and mesosoma, dorsal view D head and mesosoma, lateral view E head, anterior view F antenna G metasoma, dorsal view H metasoma, ventral view.

Interantennal process: not elongate. Median longitudinal elevation in frontal depression: absent. Frontal depression: concave. Frontal depression sculpture: with 3 broadly interrupted transverse carinae below submedian carina. Submedian carina: strong, formed by a sharp raised carina. Submedian carina medially: with sharp peak. Concavity across dorsal part of frontal depression: absent. Depression extending ventrally from median ocellus: absent. Upper frons: not hood-like. Malar area near antennal foramen: without carina or expansion. Facial striae: present. Smooth strip along posterior side of malar sulcus: absent. Genal carina: present. Direction of genal carina dorsally: parallel to eye margin. Major sculpture of gena anteriorly: foveate above genal carina, striate behind genal carina. Major sculpture of gena posteriorly: rugose. Microsculpture of gena anteroventrally: absent. Microsculpture of gena posteroventrally: granulate. Median carina extending posteriorly from hyperoccipital carina: present. Hyperoccipital carina: complete, extending ventrally around outer orbit of compound eye. Lateral connection between hyperoccipital and occipital carinae: present. Area between vertex and occipital carina: rugose; foveate. Occipital carina medially: convex, with a sharp median peak. Lateral corners of occipital carina: sharp and protruding.

Lateral pronotal area: without bulge projecting towards anterior pit. Transverse pronotal carina: present anteriorly and forming a corner with epomial carina. Netrion surface anteriorly: not inflected. Mesoscutum anteriorly: steep. Mesoscutal median carina: present and complete. Longitudinal carina between median carina and notauli: absent. Major sculpture of medial mesoscutum anteriorly: punctate; rugose. Major sculpture of medial mesoscutum posteriorly: punctate. Microsculpture of medial mesoscutum anteriorly: granulate. Microsculpture of medial mesoscutum posteriorly: granulate. Major sculpture of mesoscutellum: foveate; longitudinally rugose. Microsculpture of mesoscutellum medially: absent. Microsculpture of mesoscutellum laterally: absent. Mesoscutellar apex: straight. Setae along anterior limit of femoral depression: arising from rows of foveae. Number of carinae crossing speculum above femoral depression: 3. Number of carinae crossing femoral depression: more than 5. Mesepimeral sulcus pits: more than 5. Metascutellum dorsally: concave. Metascutellar sculpture dorsally: rugose. Median carina of metascutellum: absent. Metascutellar setae: absent. Metascutellar apex: convex. Metapleuron above ventral metapleural area: rugose. Metasomal depression setae: absent. Lateral propodeal carinae anteromedially: strongly diverging. Anterior areoles of metasomal depression: present. Anterior longitudinal carinae in metasomal depression: absent. Lateral propodeal areas: separated medially. Postmarginal vein: absent. Fore wing apex: reaching beyond T5.

T1 midlobe: with 4 longitudinal carinae. T1: without anterior bulge. T2: with straight longitudinal striae. T6: broader than long. Metasomal apex: rounded. Major sculpture of T6: punctate. Microsculpture of T6: absent. S2: with longitudinal rugae. S5: with longitudinal striae. S6: punctate.

Male. Unknown.

Diagnosis

Female: A4 and A5 broader than long. Frons without elevation between antennal foramen and eye. Gena with 3 striae below genal carina. Hyperoccipital carina present, extending ventrally around outer orbit of compound eye. Medial mesoscutum punctate. Metascutellum without dorsal setae. T1 with 4 longitudinal carinae. Oxyscelio striae is similar to O. ogive but can be separated from the latter by the darker radicle (yellowish in O. ogive), rugose metascutellum (smooth in O. ogive).

Etymology

The name striae refers to the striate gena of this species. The epithet is used as a noun in apposition.

Material examined

Holotype , female: China: Yunnan, Xishuangbanna, Menghai, Bulangshan Village, 1610 m, Area D, grass, 21°44.761'N, 100°26'E, 28.V–28.VI.2019, Li Ma, Malaise trap, SCAU 3048667 (deposited in SYSBM). Paratypes: (2 females) China: 1 female, same data as holotype, SCAU 3048664 (SYSBM); 1 female, same data as holotype, except 20.VI–20.VII.2018, SCAU 3049056 (SYSBM).

Distribution

China (Yunnan).

The key to females of the Chinese Oxyscelio published by Mo et al. (2020) could be updated to accommodate O. stenos and O. striae by replacing couplet 22 as follows

22 Mesoscutellum with a strong median carina 22'
– Mesoscutellum without a strong median carina 23
22' Frontal depression with median longitudinal elevation (Fig. 5E); genal carina without adjacent striae (Fig. 5D) Oxyscelio stenos Mo & Chen, sp. nov.
– Frontal depression without median longitudinal elevation; genal carina with adjacent striae 22"
22" Radicle yellowish; metascutellum smooth dorsally Oxyscelio ogive Burks
– Radicle dark brown (Fig. 6F); metascutellum rugose dorsally (Fig. 6C) Oxyscelio striae Mo & Chen, sp. nov.

Discussion

In the last few years, DNA barcode-based approaches have become increasingly popular for the identification of Scelionidae, especially for economically important genera such as Trissolcus Ashmead, Telenomus Haliday and Gryon Haliday (Liao et al. 2019; Talamas et al. 2019; Chen et al. 2020). These approaches not only provide evidence of species boundaries that supplement morphological identifications, but also become invaluable means of confirmation in some cases (Talamas et al. 2019). In this study, we provide COI sequences for 22 species of Oxyscelio, comprising more than half of all the species of the genus known from China. Our results indicate that the use of DNA barcoding for the identification of Oxyscelio species is promising. For example, Burks et al. (2013a) noted that O. intermedietas might be a small-bodied relative of O. granorum, but both species were treated as new species based on several subtle differences. Our molecular data support the treatment of O. intermedietas and O. granorum as distinct species (Burks et al. 2013a; Suppl. material 1: Table S1; Figure 1). The new species, O. latheticus, is another similar case. Oxyscelio latheticus is extremely similar to O. convergens and only differs from the latter by subtle differences, including the shapes of A4, A5 and the metascutellum; however, the COI sequences provide strong evidence that these are different species, with a 12.8% maximum interspecific genetic distance between the two species. This example indicates that DNA barcoding is also useful in discovering new species, especially in taxa suspected of harboring cryptic species, such as platygastroid wasps.

Acknowledgements

We are grateful to Drs. Li Ma (Yunnan Agricultural University), Shixiao Luo (South China Botanical Garden) and Chengjin Yan (Wenzhou Vocational College of Science and Technology) for providing fresh specimens for DNA analysis. This study is supported in part by the National Natural Science Foundation of China (31900346), the Natural Science Foundation of Guangdong Province (2019A1515010588) and the Wencheng County’s Second Phase of Innovation and Entrepreneurship Seed Fund in 2019 (2019NKY09).

References

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Supplementary material

Supplementary material 1 

Table S1. Genetic distances between COI sequences of Oxyscelio from southern China

Wen-hui Mo, Hua-yan Chen, Hong Pang, Jing-xian Liu

Data type: Doc file

Explanation note: Pairwise distances of 49 COI sequences of 22 Oxyscelio species.

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.
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