Strumigenys zhenghuii, Tang & Guénard, 2023

Tang, Kit Lam & Guénard, Benoit, 2023, Further additions to the knowledge of Strumigenys (Formicidae: Myrmicinae) within South East Asia, with the descriptions of 20 new species, European Journal of Taxonomy 907, pp. 1-144 : 129-132

Strumigenys zhenghuii sp. nov.

urn:lsid:zoobank.org:act:5B0E49AF-B3AC-44A0-A66E-6C3C85E276E7

Fig. 44 ; Tables 2 , 6

Diagnosis

Strumigenys zhenghuii sp. nov. can be distinguished from other species in the S. leptothrix -group by a combination of the following characters: cephalic dorsum with appressed subspatulate to linear setae; in profile view, erect setae present sporadically across cephalic dorsum, not restricted to area between highest point of vertex and th occipital margin; pronotum marginated dorsolaterally; side of mesosoma completely smooth and shining; in profile view, propodeal spines subtended by broad lamellae; femora, tibiae and basitarsi with long erect setae.

Etymology

The species is named after Dr Zhenghui Xu in recognition of his remarkable work on ants in China. The name was created by adding the singular Latin genitive case suffix -i to the given name of a male person.

Type material

Holotype worker ( Fig. 44 )

MAINLAND CHINA • Yunnan Province, Jinghong ; 7–12 Aug. 2006; S. Onoda leg.; SWFC ANTWEB1010905 .

Paratype worker

MAINLAND CHINA • 1 worker; same collection data as for holotype; KUM ANTWEB1010906 .

Measurements

Holotype worker

TL 3.1, HL 0.78, HW 0.59, MandL 0.12, SL 0.35, EL 0.089, PW 0.31, ML 0.78, PL 0.34, PH 0.16, DPW 0.13, PPL 0.21, GL 0.82, CI 76, MI 16, SI 58, OI 15, LPI 47, DPI 38.

Paratype worker

TL 3.2, HL 0.78, HW 0.62, MandL 0.13, SL 0.37, EL 0.082, PW 0.32, ML 0.82, PL 0.38, PH 0.16, DPW 0.14, PPL 0.21, GL 0.83, CI 79, MI 17, SI 59, OI 13, LPI 42, DPI 36 (n= 1).

Worker description

HEAD. In full-face view, occipital margin deeply, broadly concave; occipital corners well developed and bluntly angular; occipital carina present. Clypeus broader than long, around 1.3–1.4 times as long, roughly resembling inverted diamond. Scapes subcylindrical, marginated but not converging anteriorly to form thin lamella at leading edge. Mandibles in full-face view triangular; masticatory margins engaged across entire length, without diastema or gap between mandibles. In profile view, eye with four ommatidia in diameter.

MESOSOMA. In profile view, promesonotal dorsum weakly convex, propodeum more or less flat transversely; pronotum marginated dorsolaterally. In dorsal view, anterior margin and lateral margins of pronotum converged into blunt angle; lateral margins mostly straight and subparallel in anterior portion, converge posteriorly to meet lateral margins of mesonotum. In profile view, propodeal spines elongated-triangular, subtended on each side by broad lamella with concave posterior margin broadening basally into rounded convex propodeal lobe ( Fig. 44B ). Metapleural gland bulla well developed.

METASOMA. In profile view, petiolar peduncle grading evenly into node, and about as long as (or slightly shorter than) node. In dorsal view, petiolar node longer than broad, around 1.5–1.6 times as long; disc of postpetiole broader than long, around 1.2–1.4 times as long. Areolate processes (spongiform tissues) present on both petiole and postpetiole; ventral lobes of petiole and postpetiole extensive; lateral lobe of petiole forming moderately extensive flap at posterolateral angle of node in profile; in dorsal view, processes present along lateral and posterior margins of petiolar node, and surrounding disc of postpetiole, thicker along lateral and posterior margins than on the anterior margin.

PILOSITY. In full-face view, cephalic dorsum with appressed setae, ranging from subspatulate setae near occipital margin to linear setae near posterior clypeal margin; clypeal dorsum covered with linear to narrowly elliptic setae; mandibular dorsum covered with small oblanceolate setae; masticatory margins each with row of medially-directed fine setae. Surface of scape and funiculus (except for apical antennomere) covered with appressed acicular setae; progressively finer setae densely covering apical antennomere. Lateral margin of occipital lobe with around five laterally-projecting setae; dorsolateral margin of head and leading edge of scape with decumbent setae. In dorsal view, promesonotal dorsum sparsely with appressed subspatulate setae; posteriorly-directed decumbent setae present along lateral margins. Pronotal humeral seta long, straight and stout. In profile view, erect setae present sporadically across cephalic dorsum, not restricted to area between highest point of vertex and occipital margin; suberect to erect setae also present on mesonotal dorsum in three pairs, on petiole in two pairs, on disc of postpetiole in one pair and all over gastral tergites; similar but suberect setae also present on gastral sternites; ventral surface of head with decumbent setae. Hairwheel present at mesopleural excavation and well developed. Surfaces of middle and hind femora, tibiae and basitarsi with long stout erect setae.

SCULPTURE. Cephalic dorsum, clypeal dorsum and ventral surface of head sparsely reticulate-rugulose, with spaces between rugulae weakly areolate-rugulose; surface of antennal scrobe, antenna and legs (except first coxa) densely areolate; first coxa mostly densely areolate with smooth patch of surface. Mesosomal dorsum predominantly, relatively weakly areolate, with weak longitudinal rugulae and long, weak, longitudinal median striation; dorsum of petiolar node transversely areolate-rugulose; side of mesosoma smooth and shining. Disc of postpetiole mostly smooth and shining. Basigastral costulae short, around one third in length of first gastral tergite; rest of gaster smooth and shining.

Comments

Strumigenys zhenghuii sp. nov. is a member of the S. leptothrix -group and shares all its characters ( Bolton 2000), and very likely belongs to the elegantula -complex. The type specimens all have closed mandibles and the view is obscured by setae along the inner margin of mandible, making an accurate assessment of the dentition difficult. Placing the specimen against backlight suggests the presence of a principal dental row of around 8 teeth, alternating between short and long teeth, followed by around 4 smaller teeth and 4 denticles, terminating in a small apical tooth.

Aside from Strumigenys zhenghuii sp. nov., there are six other SEA species from the same species group ( S. ailaoshana , S. delicata sp. nov., S. densissima sp. nov., S. elegantula , S. intermedia sp. nov. and S. nankunshana ) that share the following characters: both appressed and erect setae present on the cephalic dorsum, pronotum marginate dorsolaterally, propodeal spines present and subtended by broad lamellae ( Table 6 ). For S. zhenghuii , its pronotum dorsum is areolate-rugulose (instead of predominantly longitudinally-striated as in S. ailaoshana , or predominantly transversely-striated as in S. nankunshana ); erect setae are present sporadically across the cephalic dorsum (instead of only restricted to the area between the highest point of the vertex and the occipital margin as in S. ailaoshana , S. densissima , S. elegantula or S. nankunshana ); the appressed setae on the cephalic dorsum are subspatulate to linear (instead of fine setae as in S. delicata ). Unlike all of the above six species, the side of the mesosoma is completely smooth and shining (instead of partially to fully sculptured). Strumigenys zhenghuii (CI 76– 79) also has a proportionally wider head than the abovementioned species (CI 68–74). See comments under S. intermedia for a detailed comparison between the newly described species and the existing species from S. leptothrix -group.

Geographic range

Mainland China (Yunnan).

Ecology

Collected in forest. No other information available.

Figures

Fig. 44. Type specimens of Strumigenys zhenghuii sp. nov. A, C–D. Holotype worker (ANTWEB 1010905). B. Paratype worker (ANTWEB1010906). A. Full-face view. B. Mesosoma close-up in profile view. C. Profile view. D. Dorsal view.