Strumigenys liuweii, 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 : 80-83

Strumigenys liuweii sp. nov.

urn:lsid:zoobank.org:act:0D103932-48C3-47A3-A6B3-793A76F62781

Fig. 27 ; Tables 2 , 8

Diagnosis

Strumigenys liuweii sp. nov. can be distinguished from other species in the S. godeffroyi -group by a combination of the following characters: mandible slightly tapered distally; apicoscrobal seta and pronotal humeral seta flagellate; pronotum and dorsum of petiolar node fully sculptured; pleurae, side of propodeum and disc of postpetiole mostly smooth and shining; propodeal spines subtended by broad lamellae; petiolar node with differentiated anterior face, not claviform; gastral tergites covered with erect or looped flagellate setae; dorsal surface of femur without any erect seta; hind tibiae and basitarsi without any long projecting flagellate seta; HL 0.71–0.73, MI 42–43, SI 97–100.

Etymology

The species is named after Liuwei Wang, Chase, who helped us collected important material from Hainan Province, China, including this new species. 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. 27 )

MAINLAND CHINA • Hainan Province, Bawangling , BWLP11; 19.09188° N, 109.20321° E; 4 Jul. 2016; L. Wang leg.; Winkler, 4 corners; primary forest; LKCNHM ANTWEB1011876 (collection code IBBL HNA-00916).

Paratype worker

MAINLAND CHINA • 1 worker; same collection data as for holotype; HKBM ANTWEB1011875 (collection code IBBL HNA-00916) .

Measurements

Holotype worker

TL 3.0, HL 0.73, HW 0.48, MandL 0.31, SL 0.47, EL 0.053, PW 0.27, ML 0.77, PL 0.28, PH 0.14, DPW 0.13, PPL 0.15, GL 0.72, CI 66, MI 42, SI 97, OI 11, LPI 50, DPI 44.

Paratype worker

TL 2.9, HL 0.71, HW 0.47, MandL 0.30, SL 0.47, EL 0.049, PW 0.26, ML 0.73, PL 0.31, PH 0.15, DPW 0.12, PPL 0.17, GL 0.72, CI 66, MI 43, SI 100, OI 10, LPI 48, DPI 39 (n=1).

Worker description

HEAD. In full-face view, occipital margin deeply concave; occipital corners well developed; preocular lamina wide; anterior clypeal margin mostly transverse. Scapes subcylindrical, marginated but not converging anteriorly to form thin lamella at leading edge; apical antennomere unconstricted basally. Mandible curvilinear but slightly tapered distally; elongated preapical tooth located close to apicodorsal tooth; preapical tooth distinctly longer than width of mandible at point where tooth arises; apicodorsal tooth markedly longer than apicoventral tooth. In profile view, eye with 2–3 ommatidia in diameter.

MESOSOMA. In profile view, promesonotal dorsum broadly convex, propodeum more or less flat transversely; pronotum not marginated dorsolaterally. In dorsal view, lateral margins of pronotum broadly convex. Propodeal teeth short and triangular, subtended on each side by broad lamella with mostly transverse posterior margin that narrowed slightly basally into rounded convex propodeal lobe. Metapleural gland bulla well developed.

METASOMA. In profile view, petiole not claviform; petiolar node with anterior face, differentiated from peduncle, petiolar peduncle about as long as node. In dorsal view, petiolar node about as broad as long; disc of postpetiole broader than long, around 1.7–1.8 times as long. Areolate processes (spongiform tissues) present on both petiole and postpetiole; ventral lobes of petiole and postpetiole extensive; lateral lobe of petiole merely a flap at posterolateral angle of node in profile; anterior face of node with remnant of process; in dorsal view, processes present along lateral and posterior margins of petiolar node, and surrounding the disc of postpetiole, thicker along lateral and posterior margins than on anterior margin.

PILOSITY. In full-face view, apicoscrobal seta flagellate; laterally-projecting seta other than apicoscrobal seta along dorsolateral margin of head absent or abraded. Antennae and mandibles covered with short appressed simple setae; dorsolateral margin of head, lateral clypeal margins, leading and trailing edges of scape with decumbent stout setae; those on edges of scape apically directed; anterior clypeal margin with medially directed acicular setae. Pronotal humeral seta long and flagellate. In profile view, cephalic dorsum, promesonotal dorsum, dorsum of petiolar node and disc of postpetiole with simple appressed to decumbent ground pilosity; petiolar node and disc of postpetiole also with long suberect to erect flagellate setae against ground pilosity; gastral tergites with numerous long erect or looped flagellate setae; ventral surface of head with short decumbent setae; gastral sternites with short suberect simple setae. Hairwheel present at mesopleural excavation. Dorsal and ventral surfaces of femur without any erect seta against ground pilosity of appressed setae; surfaces of middle and hind tibiae or basitarsi without any projecting flagellate seta.

SCULPTURE. Surface of head (including antennal scrobe), antennae, side of pronotum, mesosomal dorsum, petiolar node and legs densely areolate; mandible with sparse weak punctate sculpture and weakly areolate basally, but otherwise mostly smooth; pleurae, side of propodeum and disc of postpetiole mostly smooth and shining, with vestiges of sculpture around margins. Basigastral costulae short, around one fifth in length of first gastral tergite; rest of gaster smooth and shining.

Comments

Strumigenys liuweii sp. nov. is a member of the S. godeffroyi -group and shares all its characters ( Bolton 2000), and most likely belongs to the rofocala -complex of Subgroup B. It is possible that the lack of projecting flagellate setae on the tibiae and basitarsi in known specimens of S. liuweii (of which there are only two) is due to abrasion, hence it is also compared with species from Subgroup A of the S. godeffroyi -group below, focusing on other morphological characters. It can be confidently stated that S. liuweii does not belong to the signeae -complex of Subgroup B due to its flagellate pronotal humeral seta; it also does not belong to the mjoebergi -complex of Subgroup A due to its smooth side of the propodeum; it is unlikely to belong to the godeffroyi -complex of Subgroup A as it does not have an extensive lateral lobe of petiole.

Besides Strumigenys liuweii sp. nov., there are nine other species in the smythiesii -complex of Subgroup A that either also have a flagellate apicoscrobal seta ( S. datryx , S. ekasura , S. fellowesi sp. nov., S. habropilosa Bolton, 2000 , S. hypoturba Bolton, 2000 , S. panaulax , S. smythiesii and S. trada ) or uncertain ( S. choii Lyu, 2007 ). For S. liuweii , its pronotal dorsum is sculptured (unlike S. choii , S. fellowesi or S. smythiesii ); the dorsum of the petiolar node is sculptured (unlike S. choii , S. datryx or S. smythiesii ); the disc of the postpetiole is smooth and shining (unlike S. ekasura or S. panaulax ); the pilosity on the gaster is long and flagellate, erect or looped (instead of predominantly simple as in S. hypoturba or S. trada ). Strumigenys liuweii lacks the characteristic spatulatiform pilosity on the cephalic dorsum of S. choii , S. fellowesi or S. hypoturba . Strumigenys liuweii has a considerably longer scape (SI 97–100) than S. datryx , S. ekasura or S. panaulax (SI 68–83), and longer mandibles (MI 42–43) than S. habropilosa (MI 34). Strumigenys liuweii (HL 0.71–0.73, ML 0.73–0.77) is also a larger species than S. habropilosa (HL 0.62, ML 0.62) or S. hypoturba (HL 0.64, ML 0.69).

Strumigenys liuweii sp. nov. can be distinguished from other members of the rofocala -complex of Subgroup B ( S. baal Bolton, 2000 , S. edaragona Bolton, 2000 , S. frivola Bolton, 2000 and S. rofocala Bolton, 2000 ) by the following characters ( Table 8 ): disc of postpetiole is mostly smooth and shining (instead of sculptured as in S. frivola ); the apical antennomere is not constricted basally (unlike S. edaragona ); the side of the propodeum is mostly smooth and shining (unlike S. baal ); the mandibles are tapered slightly apically (unlike S. edaragona , S. frivola or S. rofocala ). Strumigenys liuweii (TL 2.9–3.0) is also a much larger species than S. rofocala (TL 1.8–1.9).

Geographic range

Mainland China (Hainan).

Ecology

Collected in primary forest.

Figures

Fig. 27. Holotype worker (ANTWEB1011876) of Strumigenys liuweii sp. nov. A. Full-face view. B. Profile view. C. Dorsal view.