Research Article |
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Corresponding author: Xu Wang ( wangxu0322@ahnu.edu.cn ) Corresponding author: Zhisheng Zhang ( zhangzs327@qq.com ) Corresponding author: Huayan Chen ( chen.4084@osu.edu ) Academic editor: Jonah M. Ulmer
© 2025 Yuanhan Yang, Fang Li, Yixin Huang, Xu Wang, Zhisheng Zhang, Huayan Chen.
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:
Yang Y, Li F, Huang Y, Wang X, Zhang Z, Chen H (2025) Description of two new species of Conostigmus Dahlbom, 1858 (Hymenoptera, Megaspilidae) from Yintiaoling Nature Reserve, Chongqing, China. ZooKeys 1255: 379-394. https://doi.org/10.3897/zookeys.1255.154710
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Two new species of Conostigmus Dahlbom, 1858, C. rotundus Yang & Wang, sp. nov. and C. clayulatus Yang & Wang, sp. nov. are described from the Yintiaoling Nature Reserve, Chongqing, China. The 28S rDNA sequences of the new species were generated to associate the female and male of the same species.
28S rDNA, Ceraphronoidea, identification key, morphology, parasitoid wasps, taxonomy
Megaspilidae belongs to Ceraphronoidea of Hymenoptera. It is widely distributed throughout the world except for the polar regions (
Considering that sexual dimorphism is common in Conostigmus, it is difficult to match male and female individuals of the same species by morphological identification alone. Molecular identification is necessary to associate both sexes of the same species.
In the present paper, we describe two new species of Conostigmus, C. rotundus Yang & Wang, sp. nov., and C. clayulatus Yang & Wang, sp. nov. from Chongqing, China, bringing the Chinese species number of Conostigmus up to ten (
The specimens in this study were collected from sweep-net and yellow pan traps. Specimens were deposited in the
Insect Collection of Anhui Normal University (
All voucher specimens were then observed and dried in the air. The specimens were photographed using a Leica M205A stereo microscope and a Leica DFC-500 digital camera. Image stacking was performed with Leica Microsystems CMS GmbH. To facilitate the preparation of male genitalia for morphological study, apical metasomal segments were dissected from specimens and subjected to a graded chemical processing protocol: first incubated in 35% H2O2 for 24 h, then transferred to 5% acetic acid for 24 h of further treatment, followed by a 1-h rinse in distilled water. After post-processing, the segments were transferred to a glycerin microdroplet on a concavity slide, and subsequent microdissection was performed in glycerin using #5 fine forceps and #2 insect pins as dissecting instruments. Measurements are given in microns. Morphological terminology follows the Hymenoptera Anatomy Ontology (
| F1, F2, ..., F9 | Flagellum 1, 2, ..., F9. |
|---|---|
| LOL | Lateral ocellar length, shortest distance between inner margins of median and lateral ocelli. |
| OOL | Ocular ocellar length, minimum distance between a posterior ocellus to the eye margin. |
| POL | Posterior ocellar length, shortest distance between inner margins of posterior ocelli. |
| HH | Head height, lateral. |
| EHf | Eye height, anterior view. |
| HL | Head length. |
| HW | Head width. |
| IOS | Interorbital space. |
| AseW | Anterior mesoscutal width. |
| PscW | Posterior mesoscutal width. |
According to previous studies, sexual dimorphism is prevalent in Conostigmus (
| Species | Sex | GenBank accession No. | Reference |
|---|---|---|---|
| D. carpenteri | male | MZ340592 | Wang et al. (2021) |
| female | MZ340590 | Wang et al. (2021) | |
| D. laticeps | male | MZ340593 | Wang et al. (2021) |
| female | MZ340624 | Wang et al. (2021) | |
| D. bellus | male | MZ344975 | Wang et al. (2021) |
| female | MZ344976 | Wang et al. (2021) | |
| D. anisodontus | male | MZ344977 | Wang et al. (2021) |
| female | MZ344978 | Wang et al. (2021) | |
| D. lui | male | OR120392 | Li et al. (2023) |
| female | OR120391 | Li et al. (2023) | |
| C. xui | male | SAMN44283636 | this study |
| C. nankunensis | male | SAMN44283637 | this study |
| C. ampullaceus | male | SAMN44283638 | this study |
| female | SAMN44283639 | this study | |
| C. rotundus sp. nov. | male | SAMN44283640 | this study |
| female | SAMN44283641 | this study | |
| C. clayulatus sp. nov. | male | SAMN44283642 | this study |
| female | PQ686133 | this study |
The genetic distances were calculated under the Kimura 2-parameter (K2P) model in MEGA X (
Conostigmus Dahlbom, 1858: 291.
Dichogmus Thomson, 1858: 287.
Eumegaspilus Ashmead, 1888: 48.
Eumegalospilus: Schulz, 1906: 152.
Conostigmoides Dodd, 1914: 88.
Ecnomothorax Dessart & Masner, 1965: 276.
Dolichoceraphron Hellén, 1966: 15.
Szelenyides Dessart, 1974: 43.
| 1 | Mesosoma distinctly elongate, length more than 2.0 × maximum width | C. ampullaceus Dessert, 1997 |
| – | Mesosoma moderately narrow, length 2.0 × or less than maximum width | 2 |
| 2 | Facial pit absent | 3 |
| – | Facial pit present | 6 |
| 3 | Anteromedian projection of metanoto-propodeo-metapecto-mesopectal complex present | 4 |
| – | Anteromedian projection of metanoto-propodeo-metapecto-mesopectal complex absent | 5 |
| 4 | Sternaulus extending to 2/3 length of mesopleuron | C. asperatus Wang & Zhu, 2025 |
| – | Sternaulus extending to 4/5 length of mesopleuron; facial sulcus present | C. clayulatus Yang & Wang, sp. nov. |
| 5 | Harpe shorter than gonostipes | C. nankunensis Qian & Wang, 2024 |
| – | Harpe longer than gonostipes | C. abdominalis Boheman, 1832 |
| 6 | Flagellomere 1 (F1) longer than scape | C. longus Wang & Zhu, 2025 |
| – | Flagellomere 1 (F1) shorter than or equal in length to scape | 7 |
| 7 | Body length (excluding antennae) ≥ 2.0 mm | 8 |
| – | Body length (excluding antennae) < 2.0 mm | 10 |
| 8 | Basal gastral carinae length ≥ 1/3 of syntergum length | 9 |
| – | Basal gastral carinae length < 1/3 of syntergum length; harpe longer than gonostipes | C. xui Cui & Wang, 2023 |
| 9 | F1 subequal to scape; head and mesosoma reddish brown | C. electrinus Wang & Chen, 2024 |
| – | F1 shorter than scape; head and mesosoma black | C. villosus Dessert, 1997 |
| 10 | Preoccipital furrow present and extends into the ocellar triangle | C. acutus Wang & Chen, 2024 |
| – | Preoccipital furrow present but does not extend into the ocellar triangle | 11 |
| 11 | Scutellum as long as wide; dorsal margin of S9 straight | C. rotundus Yang & Wang, sp. nov. |
| – | Scutellum longer than wide; dorsal margin of S9 protruded | C. quadripetalus Wang & Chen, 2024 |
The new species can be distinguished from other Conostigmus species by the following characters: facial sulcus absent; sternaulus present, elongate and reaching 4/5 of mesopleuron length; scutellum as long as wide; harpe simple, not bilobed, distal margin of harpe straight, and pointed laterally; and S9 bowl shaped, concave tip.
Holotype. ♂, China • Chongqing Municipality, Wuxi County, Yintiaoling Nature Reserve, Mt. Guanshan, 31°31'5.65"N, 109°42'59.07"E, alt. 1978 m, 22 July 2024, F. Li, W. J. Zhao, Y. C. Li leg. (CQWX-2402-0701-29). Paratypes. 1♂1♀, China • Chongqing Municipality, Wuxi County, Yintiaoling Nature Reserve, Mt. Guanshan, 31°31'5.65"N, 109°42'59.07"E, alt. 1978 m, 22 July 2024, F. Li, W. J. Zhao, Y. C. Li leg. (CQWX-2402-0701-28/32).
Male: Body length 1.4–1.6 mm (N = 2).
Coloration
(Fig.
Head
(Fig.
Antennae
(Fig.
Mesosoma
(Fig.
Wing
(Fig.
Metasoma
(Fig.
Male genitalia
(Fig.
Female (Fig.
This new species is similar to C. acutus Wang & Cui, 2024 in body length, preoccipital lunula, preoccipital furrow and lateral propodeal carina but can be distinguished by the almost circular scutellum (subcircular, subequal in length and width, more distinct than that in C. acutus); and the harpe straight apically and distal margin pointed in lateral view (harpe outward apically and distal margin beveled in lateral view). And this new species is similar to C. quadripetalus Wang & Chen, 2024 in the preoccipital lunula, preoccipital furrow, syntergum and harpe shape, but can be distinguished by body length (a longer body length than C. quadripetalus); S9 shape (male S9 shape of C. quadripetalus convex in distal margin but concave in C. rotundus); and HH: HL (a higher head height than C. quadripetalus).
China (Chongqing).
Consistent with the genus name, the species name is a Latin masculine adjective meaning “rounded”, referring to the nearly round scutellum of this species.
The new species can be distinguished from other Conostigmus species by the following characters: facial sulcus present and extends from the median ocellus to the intertorular carina; sternaulus present, elongate and reaching 3/4 of mesopleuron length; harpe with numerous long and slender apical setae and sparse lateral setae; and S9 cup-shaped with a straight tip bearing six setal patches at the end.
Holotype. ♂, China • Chongqing Municipality, Wuxi County, Yintiaoling Nature Reserve, Cotton Hill, 31°30'38.35"N, 109°42'4.54"E, alt. 2188 m, 22 July 2024, F. Li, W. J. Zhao, Y. C. Li leg. (CQWX-2402-0707-18). Paratypes. 1♂, China • Chongqing Municipality, Wuxi County, Yintiaoling Nature Reserve, Mt. Guanshan, 31°32'12.43"N, 109°41'58.38"E, alt. 2155 m, 21 July 2024, F. Li, W. J. Zhao, Y. C. Li leg. (CQWX-2402-0702-13). 1♀, China • Chongqing Municipality, Wuxi County, Yintiaoling Nature Reserve, Cotton Hill, 31°30'38.35"N, 109°42'4.54"E, alt. 2188 m, 22 July 2024, F. Li, W. J. Zhao, Y. C. Li leg. (CQWX-2402-0707-20).
Male: Body length 2.1–2.2 mm (N = 2).
Coloration
(Fig.
Head
(Fig.
Antennae
(Fig.
Mesosoma
(Fig.
Wing
(Fig.
Metasoma
(Fig.
Male genitalia
(Fig.
Female (Fig.
This new species is similar to C. bipunctatus Kieffer, 1907 in body length, axillular carinae, lateral propodeal carinae, but can be distinguished by the shorter, rod-shaped harpe (inverted U-shape in C. bipunctatus).
China (Chongqing).
Consistent with the genus name, the species name is a Latin masculine adjective meaning “clubbed”, referring to the small club-shaped harpe of the male genitalia in this species.
In this study, we obtained eight 28S rDNA sequences of five Conostigmus species. The genetic distances between C. rotundus Yang & Wang, sp. nov. and each of the other four Conostigmus species from China ranged from 0.003 to 0.020, and the genetic distances between C. clayulatus Yang & Wang, sp. nov. and each of the other four Conostigmus species from China ranged from 0.015 to 0.026 (Table
Genetic distance of 28S of ten Conostigmus and Dendrocerus species from China.
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1. Dendrocerus carpenteri, male | ||||||||||||||||||
| 2. Dendrocerus carpenteri, female | 0.000 | |||||||||||||||||
| 3. Dendrocerus laticeps, male | 0.007 | 0.007 | ||||||||||||||||
| 4. Dendrocerus laticeps, female | 0.007 | 0.007 | 0.000 | |||||||||||||||
| 5. Dendrocerus bellus, male | 0.029 | 0.029 | 0.022 | 0.022 | ||||||||||||||
| 6. Dendrocerus bellus, female | 0.029 | 0.029 | 0.022 | 0.022 | 0.000 | |||||||||||||
| 7. Dendrocerus anisodontus, male | 0.012 | 0.012 | 0.005 | 0.005 | 0.024 | 0.024 | ||||||||||||
| 8. Dendrocerus anisodontus, female | 0.012 | 0.012 | 0.005 | 0.005 | 0.024 | 0.024 | 0.000 | |||||||||||
| 9. Dendrocerus lui, male | 0.029 | 0.029 | 0.022 | 0.022 | 0.041 | 0.041 | 0.020 | 0.020 | ||||||||||
| 10. Dendrocerus lui, female | 0.029 | 0.029 | 0.022 | 0.022 | 0.041 | 0.041 | 0.020 | 0.020 | 0.000 | |||||||||
| 11. Conostigmus xui, male | 0.084 | 0.084 | 0.079 | 0.079 | 0.079 | 0.079 | 0.083 | 0.083 | 0.084 | 0.084 | ||||||||
| 12. Conostigmus nankunensis, male | 0.095 | 0.095 | 0.092 | 0.092 | 0.088 | 0.088 | 0.092 | 0.092 | 0.094 | 0.094 | 0.019 | |||||||
| 13. Conostigmus ampullaceus, male | 0.086 | 0.086 | 0.081 | 0.081 | 0.081 | 0.081 | 0.084 | 0.084 | 0.086 | 0.086 | 0.002 | 0.017 | ||||||
| 14. Conostigmus ampullaceus, female | 0.086 | 0.086 | 0.081 | 0.081 | 0.081 | 0.081 | 0.084 | 0.084 | 0.086 | 0.086 | 0.002 | 0.017 | 0.000 | |||||
| 15. Conostigmus rotundus, male | 0.090 | 0.090 | 0.084 | 0.084 | 0.084 | 0.084 | 0.088 | 0.088 | 0.090 | 0.090 | 0.005 | 0.020 | 0.003 | 0.003 | ||||
| 16. Conostigmus rotundus, female | 0.090 | 0.090 | 0.084 | 0.084 | 0.084 | 0.084 | 0.088 | 0.088 | 0.090 | 0.090 | 0.005 | 0.020 | 0.003 | 0.003 | 0.000 | |||
| 17. Conostigmus clayulatus, male | 0.099 | 0.099 | 0.094 | 0.094 | 0.094 | 0.094 | 0.097 | 0.097 | 0.099 | 0.099 | 0.017 | 0.026 | 0.015 | 0.015 | 0.019 | 0.019 | ||
| 18. Conostigmus clayulatus, female | 0.099 | 0.099 | 0.094 | 0.094 | 0.094 | 0.094 | 0.097 | 0.097 | 0.099 | 0.099 | 0.017 | 0.026 | 0.015 | 0.015 | 0.019 | 0.019 | 0.000 |
We reconstructed a maximum-likelihood tree (ML tree) using 28S rDNA sequences from 12 species, including two Ceraphron species as outgroups, five species of Conostigmus, and five species of Dendrocerus as ingroups. The results of ML tree showed that C. xui diverged first, as the sister to the rest species. This clade was followed by C. ampullaceus. The topology was as (C. xui + (C. ampullaceus +(C. clayulatus + (C. rotundus + (C. nankunensis + D. lui Li & Wang, 2023))))) (Fig.
The 28S rDNA sequences showed that the female and male of the same Conostigmus sepcies are genetically identical, which was consistent with the results of morphological identification, which implies that the 28S sequence can be used for matching male and female specimens of the same Conostigmus species.
Although the 28S sequences contained insufficient phylogenetic signal to reliably reconstruct overall relationships, they nonetheless support the assignment of C. rotundus Yang & Wang, sp. nov. and C. clayulatus Yang & Wang, sp. nov. to the genus Conostigmus.
The authors have declared that no competing interests exist.
No ethical statement was reported.
No use of AI was reported.
This work was supported by the National Natural Science Foundation of China (Grant Nos. 32100352, 32100355), the Key Program of the National Natural Science Foundation of China (Grant No. 32330013), the Key Laboratory of Zoological Systematics, Evolution (Grant No. 2008DP173354), the Anhui Provincial Peak Discipline of Ecology Project (No. 2025GFXK062) and the Fund on survey of invertebrates from Yintiaoling Nature Reserve (CQS21C00739, CQS24C00333).
All authors have contributed equally.
Yuanhan Yang https://orcid.org/0009-0009-5964-5835
Fang Li https://orcid.org/0009-0004-9269-7200
Yixin Huang https://orcid.org/0000-0002-7885-321X
Xu Wang https://orcid.org/0000-0001-6465-4052
Zhisheng Zhang https://orcid.org/0000-0002-9304-1789
Huayan Chen https://orcid.org/0000-0002-0382-1635
All of the data that support the findings of this study are available in the main text.