Leptogenys zhoui, Chen & Chen & Xu & Fu & Fu, 2024

Chen, Chao, Chen, Zhilin, Xu, Zhenghui, Fu, Qishan & Fu, Liwen, 2024, Two new ant species of the genus Leptogenys (Hymenoptera, Formicidae) from Hainan, China, with a key to the known Chinese species, ZooKeys 1195, pp. 199-217 : 199

Leptogenys zhoui sp. nov.

Figs 2 , 4A-D

Type material.

Holotype: worker, China: Hainan Province, Baisha County, Nanmeiling forest park, Yaqiong sub-station, 19.144167°N, 109.349167°E, 700m, 2.VIII.2022, Chao Chen leg. The holotype specimen is deposited in Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences (KIZCAS), Kunming, Yunnan Province, China, Reg. No. KIZ20220196 (unique specimen identifiers). Paratypes: 2 workers, data the same as holotype. One paratype worker is deposited in GXNU. No. KIZ20220197 (unique specimen identifiers); 1 paratype worker is deposited in the Insect Collection, Southwest Forestry University (SWFU), Kunming, Yunnan Province, China. No. KIZ20220198 (unique specimen identifiers)

Description.

Holotype worker (Fig. 4 ): HL 0.91, HLL 0.75, HLA 0.17, HW 0.81, ML 0.49, CML 0.12, CI 89, SL 0.68, SI 84, ED 0.10, PrL 0.69, PrH 0.49, PrW 0.61, WL 1.53, TL 4.4, PL 0.26, PH 0.46, DPW 0.35, LPI 174, PDPI 135.

Head in full-face view slightly wider anteriorly than posteriorly with straight posterior margins and narrowly rounded posterior corners. Lateral margins exhibit a subtle convexity. Mandibles display parallel inner and outer margins, with masticatory margin adorned with three or four teeth. Anterior portion of clypeus concave medially, while dentate protrusions emerge on both sides. Short frontal ridge extends slightly beyond upper end of eyes, and well-developed frontal lobes cover antennal sockets. 12-segmented antennae boast thickened funiculus towards the end, with scape reaching just to posterior head corner. Eyes, of medium size, have maximum diameter ~ 2/3 that of scape and located at 1/5 in front of lateral cephalic margin (HLL 0.75, HLA 0.17).

In lateral view, promesonotum slightly raised, with distinct promesonotal suture and metanotal groove absent. Promesonotum pleural suture and meso-metathoracic pleural suture evident, terminating at metathoracic spiracle. Dorsum of propodeum appears nearly straight, maintaining same horizontal plane as promesonotum, with slightly convex declivity. Length of dorsum of propodeum is ~ 1.5 × that of declivity, with curved transition from slope at back. Petiolar node carries a roughly trapezoidal shape, with weakly convex anterior margin and straight posterior margin, with convex dorsal margins. Well-developed subpetiolar process features a rounded anterior corner. Gaster adopts an approximately cylindrical form, with sting extruding.

In dorsal view, promesonotal suture distinct, while metanotal groove absent. Pronotum anteriorly a round shape, lateral margins convex. Mesonotum trapezoidal, wider in front and narrowing towards back. Propodeum square, with slightly convex lateral margins. Petiolar node dorsum semicircular, with round front and transverse posterior margin, ~ 1.8 × wider than its length (PL 0.26, PH 0.46).

Mandibles exhibit sparse pits along inner edge, while both sides of clypeus display longitudinal striae. Funiculus appears densely punctate, while remainder of body smooth and shiny. Erect or suberect hairs abundant abaxially on body, with only funiculus adorned with dense decumbent pubescence. Body reddish brown.

Paratype worker: HL 0.89-0.90, HLL 0.74-0.75, HLA 0.17, HW 0.81-0.83, ML 0.47-0.50, CML 0.11-0.12, CI 91, SL 0.67-0.68, SI 82, ED 0.10, PrL 0.62, PrH 0.46-0.47, PrW 0.60-0.61, WL 1.42-1.48, TL 4.1-4.2, PL 0.26, PH 0.43-0.45, DPW 0.34-0.37, LPI 165-172, PDPI 131-140 (n = 2). Similar to holotype worker.

Queen and male. Unknown.

Comparative notes.

The new species is compared against species within the L. crassicornis species group, characterized by a square head, a smooth appearance, mandibles with a dentate masticatory margin, and short antennae. The new species exhibits the closest resemblance to Leptogenys crassicornis Emery, 1895 (Fig. 5A-C ). In full-face view of the new species, sparse pits adorn the inner edge of the mandibles, while the middle part of the anterior clypeus displays a concave feature and forms dentate protrusions on both sides. The eyes are of moderate size, with a maximum diameter of ~ 2/3 of the maximum diameter of the scape. In lateral view, the petiolar node is moderately thick and ~ 1/2 the height (PL 0.26, PH 0.46), while the dorsum of the propodeum appears nearly straight and aligns with the promesonotum in the same horizontal plane. Furthermore, the body, abaxially, exhibits a profusion of erect or suberect hairs. Conversely, in L. crassicornis , 'the inner edge of the mandible lacks pits or has only one or two pits in full-face view. The anterior aspect of the clypeus is rounded, and the eyes are smaller, with a maximum diameter of ~ 1/2 of the maximum diameter of the scape. In lateral view, the petiolar node appears thick and ~ 4/5 of the height (PL 0.33, PH 0.41), while the dorsum of the promesonotum is higher than the propodeum. Additionally, the body, abaxially, bears sparse erect or suberect hairs and decumbent pubescence.

The new species bears resemblance to Leptogenys myops (Emery, 1887) (Fig. 6A-C ). In the new species, body size is relatively large (TL> 4 mm); in full-face view, the anterior clypeal margin is fringed with two or three peg-like setae medially; the antennal scape reaches just to the posterior head corner; the eyes are relatively large (ED 0.1 mm); the dorsum of the propodeum appears nearly straight and aligns with the promesonotum in the same horizontal plane. Furthermore, the body, abaxially, exhibits a profusion of erect or suberect hairs. Conversely, in L. myops , the body size is relatively small (TL <4 mm); in full-face view, the anterior clypeal margin is not fringed medially; the antennal scape does not reach the posterior head corner; the eyes are relatively small (ED 0.07 mm); the metanotal groove divides the dorsal outline of the mesosoma into two distinct convexities in lateral view; body, abaxially, bears sparse erect or suberect hairs and decumbent pubescence.

Etymology.

The newly discovered species is named in honor of Professor Shanyi Zhou of Guangxi Normal University, in commemoration of his exceptional contributions to the field of ant taxonomy in China. The name zhoui was created by adding the singular Latin genitive case suffix -i to the last name of a male person. The name is unchangeable.

Figures

Figure 2. Distribution of the two new species of Leptogenys in Hainan, China. The gradients of the map indicate the topography.

Figure 4. Leptogenys zhoui sp. nov. worker A body in lateral view B body in dorsal view C head in full-face view D mandibles in full-face view.

Figure 5. Leptogenys crassicornis worker (from AntWeb 2023, CASENT 0281924, photographer: Shannon Hartman) A body in lateral view B body in dorsal view C head in full-face view.

Figure 6. Leptogenys myops worker (from AntWeb 2023, CASENT 0281925, photographer: Shannon Hartman) A body in lateral view B body in dorsal view C head in full-face view.