Research Article |
Corresponding author: Fuming Shi ( shif_m@126.com ) Corresponding author: Shanyi Zhou ( syzhou@mailbox.gxnu.edu.cn ) Academic editor: Michael Ohl
© 2017 Zhilin Chen, John E. Lattke, Fuming Shi, Shanyi 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:
Chen Z, Lattke JE, Shi F, Zhou Z (2017) Three new species of the genus Gnamptogenys (Hymenoptera, Formicidae) from southern China with a key to the known Chinese species. Journal of Hymenoptera Research 54: 93-112. https://doi.org/10.3897/jhr.54.10816
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Three new species of the genus Gnamptogenys Roger, 1863 are described from southern China: Gnamptogenys dentihumera Chen, Lattke & Zhou, sp. n., Gnamptogenys nanlingensis Chen, Lattke & Zhou, sp. n. and Gnamptogenys quadrutinodules Chen, Lattke & Zhou, sp. n. A distribution map and an identification key to workers for the known species of China are provided.
Formicidae , Ectatomminae , Gnamptogenys , new species, key, distribution map, southern China
Gnamptogenys Roger, 1863 is the most diverse ant genus in the subfamily Ectatomminae, which is distributed throughout the tropical region except for the African and Malagasy areas (
The first described species of the genus, G. bicolor (
In this study, three new species of this genus are described from southern China. These three new species are fortunately easily distinguished from the already described species. A key to all known Chinese species and a map of distribution data are provided in this article.
This study is based on specimens deposited in the Insect Collection of Guangxi Normal University, China. The examination of the specimens was carried out with a Leica M205A stereomicroscope. High-quality multifocused montage images were captured with a Leica DFC 450 digital imaging system. GPS coordinates were recorded from labels, references or estimated from Google Earth (http://earth.google.com/). Map was constructed using the software package ArcGIS version 10.2. All measurements are in millimeters. Standard measurements and indices are mostly as defined by
CI Cephalic Index = HW × 100 / HL.
DPI Dorsal Petiole Index = DPW × 100 / PL.
DPW Dorsal Petiole Width: maximum width of petiole in dorsal view.
ED Eye Diameter: maximum diameter of eye.
HL Head Length: straight-line length of head in perfect full-face view, measured from the mid-point of the anterior clypeal margin to the midpoint of the posterior margin. In species where one or both of these margins are concave, the measurement is taken from the mid-point of a transverse line that spans the apices of the projecting portions.
HW Head Width: maximum width of head in full-face view, excluding the eyes.
LPI Lateral Petiole Index = PH × 100 / PL.
MSL Mesosoma Length: diagonal length of the mesosoma in lateral view, measured from the point at which the pronotum meets the cervical shield to the posterior basal angle of the metapleuron.
PH Petiole Height: height of petiole measured in lateral view from the apex of the ventral process (subpetiolar) vertically to a line intersecting the dorsalmost point of the node.
PL Petiole Length: length of petiole measured in lateral view from the anterior process to the posteriormost point of the tergite, where it surrounds the gastral articulation.
PW Pronotal Width: maximum width of pronotum measured in dorsal view.
SI Scape Index = SL × 100 / HW.
SL Scape Length: straight-line length of the antennal scape, excluding the basal constriction or neck.
TL Total Length: total outstretched length of the individual, from the mandibular apex to the gastral apex.
Holotype. Worker. CHINA: Guangxi, Huanjiang County, Jiuwan Mountain, 25°11'00"N, 108°36'57"E, 925m, 8.VIII.2015, leg. Zhilin Chen, No. G150067. Paratypes. 12 workers and 1 queen, data the same as holotype. [1 worker holotype, 8 workers pratypes and 1 queen paratype specimens are deposited in the Insect Collection, Guangxi Normal University, Guilin, China (GXNU); 2 workers paratypes will be deposited in the Insect Collection, Southwest Forestry University, Kunming, Yunnan Province, China (SWFU); 2 workers paratypes will be deposited in the Institute of Zoology, Chinese Academy of Sciences, Beijing, China (IZCAS)].
(Figs
In lateral view occipital lamella of head forming a blunt triangular denticle. Dorsum of mesosoma strongly convex, promesonotal suture slightly impressed. Propodeum with short triangular denticle; propodeal declivity weakly concave close to tooth then relatively straight. Petiole roughly trapezoidal, about 2.1 times higher than long, dorsal and anterior margins weakly convex, posterior margin straight, subpetiolar process broadly triangular. Sting extruding.
In dorsal view anterolateral margin of pronotum with strong constriction, forming pointed denticle on humeral area. Metanotal groove ambiguously evident, evidenced by a change in sculpturing. Petiolar anterior corner rounded, lateral margin weakly convex in dorsal view.
Mandibular dorsum and clypeus with longitudinal fine striae; cephalic dorsum mostly longitudinally rugulose-foveolate; side of pronotum, propodeum, petiole and third abdominal tergite and sternite rugulose-foveolate; posteromediand pronotum and mesonotum with longitudinal striae; propleuron irregularly rugulose; meso- and metapleuron longitudinally striate; fourth abdominal tergite finely irregularly rugulose, sternite rugulae denser than on tergite. Propodeal declivity transversely striate. Head, mesosoma, petiole, and gaster with abundant suberect hairs and sparse decumbent pubescence. Scape and tibiae with sparse sub-decumbent hairs and dense decumbent pubescence. Body color black; mandible, antenna and leg reddish-brown.
(n = 12). TL 4.56–4.65, HL 1.43–1.45, HW 1.20–1.23, CI 83–85, SL 1.03–1.05, SI 84–87, ED 0.13–0.15, PW 0.94–0.95, MSL 1.70–1.72, PL 0.40–0.43, PH 0.93–0.96, DPW 0.56–0.58, LPI 230–233, DPI 137–143. General appearance as in holotype, with some specimens reddish brown to yellowish brown in color. We believe they are callow workers.
(Figs
In lateral view occipital lamella of head forming blunt point. Dorsum of mesosoma convex. Promesonotal suture obvious. Petiole relatively thin, anterior margin convex, posterior margin straight, dorsal and anterior margin with no obvious boundary, subpetiolar process broadly triangular. Sting extruding.
In dorsal view anterior margin of pronotum rounded; metanotal groove distinct. Metanotum oval, very narrow, bordered by mesoscutellum and propodeum. Petiole anterior weakly rounded.
Forewing and hindwing of queen shown in Figs
Mandibular dorsum, anterolateral cephalic surface and middle part of clypeus with fine longitudinal striae. Head, pronotum, propodeum and petiole coarsely rugulose; middle part of mesonotum longitudinally striate; propleuron irregularly rugulose; mesopleuron and metapleuron longitudinally rugulose; in lateral view, third abdominal tergite with semicircular rugulae; fourth abdominal tergite with fine short rugulae; propodeal declivity transversely striate. Head, mesosoma, petiole, and gaster with abundant sub-erect hairs and sparse decumbent pubescence; scape and tibiae with sparse sub-decumbent hairs and dense decumbent pubescence. Whole body reddish-brown.
Unknown.
This species was found nesting in deadwood of a branch on the ground in a subtropical evergreen broad-leaved forest, at the altitude of 925 m. All ants came from the same nest.
This species is named from the Latin words “dent” (denticle) and “humer” (humeral), referring to the pronotum humeral area forming a pair of pointed denticles.
The workers of G. dentihumera are similar to workers of G. panda, but G. dentihumera can be distinguished from the latter by propodeum with short triangular denticle and triangular subpetiolar process. The workers of G. dentihumera also resemble G. sinensis, but differ from the latter by the occipital lamella of head shaped as a blunt triangular denticle, and the pronotal humeral denticle of the workers of G. dentihumera is short, pointing laterally, unsurpassing the anterior margin of pronotum.
Holotype. worker. CHINA: Guangdong, Nanling National Nature Reserve, 24°54'38"N, 113°01'23"E, 1075m, 15.V.2015, leg. Zhilin Chen, No. G150025. Paratypes. 4 workers, data the same as holotype. [1 worker holotype and 2 workers paratype specimens are deposited in the Insect Collection, Guangxi Normal University, Guilin, China (GXNU); 1 worker paratype will be deposited in the Insect Collection, Southwest Forestry University, Kunming, Yunnan Province, China (SWFU); 1 worker paratype will be deposited in the Institute of Zoology, Chinese Academy of Sciences, Beijing, China (IZCAS)]
(Figs
In lateral view posterior corner of head with small narrow, non-translucent lamella. Dorsum of mesosoma strongly convex. Promesonotal suture obvious. Propodeum without denticle, posterodorsal corner rounded. Petiole roughly trapezoid, about 2.25 times higher than long, dorsal margin weakly convex, anterior and posterior margin straight; subpetiolar process broadly triangular. Sting extruding.
In dorsal view pronotal humeral angle well-developed but not protuberant; lateral margin of pronotum almost straight, anterior margin convex, posterior margin concave. Metanotal groove inconspicuous. Petiole anterior corner rounded, posterior corner blunt.
Mandible and clypeus with longitudinally fine striae; head, side of mesonotum, petiole and third abdominal tergite rugulose-foveolate; middle part of mesonotum with five longitudinal striae; pronotum, propleuron and propodeum irregularly rugulose; fourth abdominal tergite finely rugulose-punctate, sternite densely coarsely punctate; propodeal declivity with 7–8 transverse striae. Head, mesosoma, petiolar node and gaster with abundant sub-erect hairs and sparse decumbent pubescence; mandible with decumbent hairs; scape and tibiae with sparse sub-decumbent hairs and dense decumbent pubescence. Body color black; mandible, antenna, and leg reddish-brown.
(n = 3). TL 5.30–5.37, HL 1.62–1.66, HW 1.44–1.46, CI 86–88, SL 1.21–1.24, SI 82–85, ED 0.14–0.15, PW 1.20–1.22, MSL 2.10–2.13, PL 0.43–0.44, PH 1.03–1.05, DPW 0.63–0.66, LPI 237–239, DPI 148–151. As holotype.
Unknown.
This species nests in deadwood of ranch on ground in subtropical evergreen broad-leaved forest, at the altitude of 1075 m.
This species is named after its type-locality, “Nanling” National Nature Reserve of Guangdong Province, China.
The workers of Gnamptogenys nanlingensis are easily distinguished from other Gnamptogenys by a combination of the following characters: large (HW≥1.44mm); pronotal humeral angle well-developed, but not forming denticle or spine; lateral margin of pronotum strongly convex, posterior margin concave; propodeum without denticle, posterodorsal corner rounded; pronotum, propleuron and propodeum, with strongly and irregularly rugulose; fourth abdominal tergite finely rugulose-punctate.
The workers of G. nanlingensis are morphologically similar to G. sichuanensis. However, in G. nanlingensis the subpetiolar process is triangular or cuneiform, while in G. sichuanensis the subpetiolar process is polygonal, with the anteroventral corner bluntly angular, the ventral margin concave, and the posteroventral corner rounded. G. nanlingensis has a narrow and inconspicuous occipital cephalic lamella, while the cephalic lamella of G. sichuanensis is well developed, but thin and almost translucent lamella. The fourth abdominal sternite in G. nanlingensis is reticulate-rugose, while in G. sichuanensis it istransversely striate.
Holotype worker. CHINA: Jianxi, Guangfeng County, Tongbo Mountain, 28°05'35"N, 118°14'20"E, 1026m, 2.IX.2012, leg. Chunwen Lu, No. G120081. Paratypes. 2 workers, 1 male and 1 queen, data the same as holotype. [The holotype and paratypes are deposited in the Insect Collection, Guangxi Normal University, Guilin, China (GXNU)].
(Figs
In lateral view occipital lamella of head narrow and inconspicuous; dorsum of mesosoma moderately convex; promesonotal suture obvious. Propodeum with short triangular denticle; propodeal declivity longitudinally weakly concave, laterally with margin. Petiole roughly sub-quadrate, about 1.7 times higher than long, anterior corner slightly rounded, posterior corner bluntly angulate, dorsal and anterior margin weakly convex, posterior margin straight. Subpetiolar process subquadrate. Sting extruding.
In dorsal view humeral angle rounded; promesonotal suture visible; metanotal groove absent. In dorsal view petiolar node with approximate semicircular anterolateral margin, anterior margin convex and separated from lateral margin by weak blunt angle, lateral margin weakly convergent posteriorly, each margin weakly convex; posterior margin weakly concave; node about 1.5 times as long as broad; anterior petiolar corner rounded, posterior corner blunt.
Mandibular dorsum and clypeus with longitudinal fine striate; space between frontal carinae with four longitudinal striae, rest of head partly rugulose-foveolate; pronotum, propodeum, petiole and anterior two-thirds of third abdominal tergite rugulose-foveolate; middle part of mesonotum with four longitudinal striae; propleuron, mesopleuron and metapleuron irregularly rugulose; dorsum of fourth abdominal tergite smooth, sides with fine short rugulae; propodeal declivity reticulate-rugose. Head, mesosoma, petiole, and gaster with abundant sub-erect hairs. Scape and tibiae with sparse sub-decumbent hairs. Head, mesosoma and petiole black-brown; mandible, antenna, gaster and legs reddish-brown.
(n = 2). TL 4.18–4.23, HL 1.02–1.06, HW 0.84–0.87, CI 80–83, SL 0.71–0.74, SI 82–85, ED 0.08–0.09, PW 0.70–0.73, MSL 1.30–1032, PL 0.23–0.26, PH 0.61–0.63, DPW 0.48–0.51, LPI 243–245, DPI 198–202. As the holotype.
(Figs
In lateral view occipital lamella of head narrow and inconspicuous. Dorsum of mesosoma moderately convex. Promesonotal suture obvious; propodeum with short triangular denticle; propodeal declivity weakly concave. In lateral view petiole trapezoid, anterior corner slight rounded, posterior corner angulate, dorsal margin weakly convex, anterior and posterior margins straight. Subpetiolar process sub-quadrate. Sting extruding.
In dorsal view pronotal anterolateral corner rounded. Metanotal groove distinct. Petiole relatively thick, anterior margin slightly convex.
Forewing and hindwing of queen as shown in Figs
Mandible dorsum, gena and clypeus with longitudinal fine striae; head, pronotum, propodeum, propleuron and petiole coarsely rugulose; mesonotum with longitudinal striae; mesopleuron and metapleuron longitudinally rugulose; third abdominal tergite rugulose-punctate; fourth abdominal tergite with scattered piligerous punctures; declivity transversely striate. Head, mesosoma, petiolar node and gaster with abundant sub-erect hairs; scape and tibiae with sparse sub-decumbent hairs and dense decumbent pubescence. Whole body reddish-brown.
(Figs
In lateral view posterior carinae of head conspicuous. Mesoscutellum higher than mesoscutum; mesopleural oblique furrow distinctly wide. Propodeal lobe bluntly triangular; dorsum of propodeum as long as declivity, posterodorsal corner inconspicuous. Petiole elongated oval; subpetiolar process shaped as rounded translucent lamella.
In dorsal view mesosoma spindle-shaped. Parapsidal sulcus and notaulus present, notaulus conspicuous. Metanotum small, not reaching to the lateral margins. Petiole trapezoidal, anterior margin slightly convex, posterior margin straight, anterior corners rounded.
Forewing and hindwing of male as shown in Figs
Mandibular dorsum and declivity of propodeum longitudinally finely striate; head, metapleuron and petiole irregularly finely rugulose; pronotum, propleuron, mesopleuron smooth; anterior margin of first gastral tergite with short striae; declivity longitudinally striate. Head and mesosoma with abundant sub-erect hairs, petiole and gaster sparse sub-decumbent hairs and decumbent pubescence; scape and tibiae with sparse sub-decumbent hairs and dense decumbent pubescence. Whole body black-brown.
The specimens were found nesting under a stone in broadleaf forest and conifer mixed forest at the altitude of 1026 m.
This species is named from the Latin words “quadrat” (quadrate) and “nodules” (petiole), referring to its nearly square petiole.
The workers of G. quadrutinodules are distinguished from workers of other species of Gnamptogenys by the combination of the following characters: small eye, with 5 ommatidia along the maximum diameter; occipital lamella of head of head narrow and inconspicuous; petiole with anterior corner slight rounded and posterior corner bluntly angulate, node roughly sub-quadrate with dorsal and anterior margins weakly convex, posterior margin straight. Subpetiolar process sub-quadrate.
The workers of G. quadrutinodules are quite similar to those of G. coccina Zhou, 2001 and G. taivanensis (Wheeler, 1929). G. quadrutinodules can be distinguished from G. taivanensis by the rough rugose-punctate sculpturing of abdominal tergite III vs the diminished sculpturing on G. quadrutinodules, the shape of subpetiolar process seems different in the two species and the general color pattern for the workers also seems different. The distribution range of G. quadrutinodules may be sympatric with that of G. coccina (Map. 1). Most of the specimens of G. coccina were collected from sub-tropical forests of Guangxi Zhuang Autonomous Region, China, and once recorded from Hubei province by Wang et al. (2009). So far the location of G. quadrutinodules, Jiangxi province, was not found the distribution of G. coccina. But Jiangxi, Guangxi and Hubei Provices compose triangle-distributed. So the G. coccina is likely to exist in Jiangxi, and which is impossible through distribution range to roughly distinguish G. quadrutinodules from G. coccina. So far G. coccina has not been found in sympatry with G. quadrutinodules but the present records suggest the likely presence of G. coccina in Jiangxi Province so assuming allopatry as as a rough sorting criteria for the two species is probably not a good idea.
However, the worker of G. quadrutinodules is distinguished from workers of G. coccina by the following characters: Promesonotal suture ambiguous; 3–7 flagellar segments broader than long; in lateral view petiole roughly sub-quadrate, in dorsal view petiole broader than long; subpetiolar process sub-quadrate.
1 | Petiolar node in lateral view low and rounded, the anterior margin curving continuously onto the dorsal margin (Fig. |
2 |
– | Petiolar node in lateral view erect, with distinct anterior and posterior margins and a well-defined dorsal margin (Fig. |
3 |
2 | Body bicolor: head and gaster black, mesosoma orange-ferruginous; subpetiolar process polygonal to triangular with an anteroventral denticle (Fig. |
G. bicolor (Emery) |
– | Body unicolor: head, mesosoma and gaster orange-ferruginous; subpetiolar process sub-quadrate (Fig. |
G. binghamii (Forel) |
3 | In lateral view occipital lamella of head forming a blunt triangular denticle (Fig. |
4 |
– | In lateral view occipital lamella of head absent; if present, only forming a convex posterior margin, never angular (Fig. |
5 |
4 | In lateral view propodeum with short triangular denticle; subpetiolar process triangular (Fig. |
G. dentihumera Chen, Lattke & Zhou, sp. n. |
– | In lateral view propodeum without denticle, posterodorsal corner rounded; subpetiolar process polygonal, anteroventral corner bluntly angular, ventral margin straight, posteroventral corner acute (Fig. |
G. panda (Brown) |
5 | In dorsal view pronotum with a stout denticle on each humeral area (Fig. |
G. sinensis Wu & Xiao |
– | In dorsal view pronotum without denticle (33B). | 6 |
6 | In lateral view propodeum without denticle, posterodorsal corner rounded (Fig. |
7 |
– | In lateral view propodeum with denticle (Fig. |
8 |
7 | In lateral view subpetiolar process triangular or cuneiform (35A); occipital lamella narrow and inconspicuous (Fig. |
G. nanlingensis Chen, Lattke & Zhou, sp. n. |
– | In lateral view subpetiolar process polygonal, anteroventral corner angular, ventral margin concave, posteroventral corner rounded (Fig. |
G. sichuanensis Lattke |
8 | Eye medium-sized, with 7 ommatidia on maximum diameter; declivity transversely striate | G. taivanensis Wheeler |
– | Eye small-sized, with 5 ommatidia on maximum diameter; declivity irregularly rugose | 9 |
9 | In lateral view petiolar node roughly subquadrate; subpetiolar process subquadrate (Fig. |
G. quadrutinodules Chen, Lattke & Zhou, sp. n. |
– | In lateral view petiolar node roughly trapezoidal; subpetiolar process polygonal, anteroventral corner corner acute, ventral margin straight, posteroventral bluntly angular (Fig. |
G. coccina Zhou |
We are most thankful to Dr. Himender Bharti and Dr. Michael Ohl, whose suggestions helped to significantly improve the manuscript. We are grateful to Chunwen Lu (Guangxi Normal University, China) for collecting the type specimens of G. quadrutinodules. This study was supported by the National Natural Science Foundation of China (No. 31372248 & 31672343), the Ministry of Science and Technology of China (No. 2015FY210300) and Natural Science Foundation of Guangxi (No. 2016GXNSFBA380024).