Strumigenys scutica, 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 : 109-113

Strumigenys scutica sp. nov.

urn:lsid:zoobank.org:act:0ACFC95E-EF4B-4EDE-AD25-433C2F272749

Fig. 37 ; Tables 2 , 10

Diagnosis

Strumigenys scutica sp. nov. can be distinguished from other species in the S. godeffroyi -group by a combination of the following characters: apicoscrobal seta short and stout; pronotal humeral seta simple; pronotum and dorsum of petiolar node fully sculptured, side of pronotum sometimes with small smooth patch; 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 with flagellant setae, erect or looped; dorsal surface of femur without any erect seta; hind tibiae and basitarsi without any projecting flagellate seta; MI 44–49, SI 80–88.

Etymology

The species is named after the presence of flagellate setae on its gaster. The epithet ‘ scutica ’ is the nominative singular of the Latin noun ‘ scutica ’ (meaning ‘lash’).

Type material

Holotype worker ( Fig. 37 )

MAINLAND CHINA • Hainan Province, Bawangling , BWLP12; 19.09324° N, 109.20006° E; 4 Jul. 2016; L. Wang leg.; Winkler, 12 random; primary forest; LKCNHM ANTWEB1011923 (collection code IBBL HNA-00953).

Paratype workers

CHINA • 13 workers;same collection data as for holotype;HKBMANTWEB1011881,ANTWEB1011918 to ANTWEB1011922, ANTWEB1011924 to ANTWEB1011930 (collection code IBBL HNA-00953) .

Additional material examined

MAINLAND CHINA – Hainan Province • 1 worker; Bawangling, BWLP11; 19.09188° N, 109.20321° E; 4 Jul. 2016; L. Wang leg.; Winkler , 12 random; IBBL ANTWEB1011884 • 2 workers; Bawangling, BWLP5; 19.09396° N, 109.20101° E; 1 Jul. 2016; L. Wang leg.; Winkler , 12 random; IBBL ANTWEB1011882 , ANTWEB1011917 • 1 worker; Bawangling, BWLP8; 19.09125° N, 109.20155° E; 3 Jul. 2016; L. Wang leg.; Winkler , 12 random; IBBL ANTWEB1011883 .

Measurements

Holotype worker

TL 2.8, HL 0.69, HW 0.48, MandL 0.32, SL 0.41, EL 0.071, PW 0.26, ML 0.72, PL 0.29, PH 0.13, DPW 0.12, PPL 0.18, GL 0.62, CI 70, MI 46, SI 84, OI 15, LPI 44, DPI 40.

Paratype workers

TL 2.7–2.9, HL 0.67–0.76, HW 0.46–0.53, MandL 0.31–0.35, SL 0.38–0.44, EL 0.060 –0.071, PW 0.23– 0.27, ML 0.69–0.74, PL 0.25–0.32, PH 0.12–0.15, DPW 0.11–0.13, PPL 0.16–0.19, GL 0.55–0.64, CI 68–72, MI 44–49, SI 80–88, OI 12–15, LPI 42–53, DPI 39–45 (n=13).

Worker description

HEAD. In full-face view, occipital margin evenly, deeply concave; occipital corners well developed; preocular lamina wide; anterior clypeal margin very broadly, shallowly concave. Scapes subcylindrical, marginated but not converging anteriorly to form thin lamella at leading edge; apical antennomere unconstricted basally. Mandible curvilinear and long, with spiniform preapical tooth located close to apicodorsal tooth; width of mandible fairly constant from basal portion to where preapical tooth first arose; 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 three 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 evenly convex. Propodeal teeth present but inconspicuous, subtended on each side by broad lamella with broadly convex posterior margin narrowing 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 1.2–1.4 times as long. Areolate processes (spongiform tissues) present on both petiole and postpetiole; ventral lobes of petiole and postpetiole extensive; lateral lobe of petiole merely a flap at posterolateral angle of node in profile view; anterior face of the node with inconspicuous strip; 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 anterior margin.

PILOSITY. In full-face view, cephalic dorsum sparsely with appressed seta; apicoscrobal seta short and stout, sometimes truncated; around 3–4 shorter setae present posterior to it on lateral margin of occipital lobe. Antennae and mandibles covered with short appressed simple setae; upper scrobe margin, lateral clypeal margin and leading trailing edge of scape with decumbent stout to shoehorn-shaped setae; those on edges of scape apically-directed; anterior clypeal margin with medially-directed acicular setae. Pronotal humeral seta simple, sometimes slightly curved. In profile view, cephalic dorsum, mesosomal dorsum, dorsum of petiolar node and disc of postpetiole with simple erect simple setae; those on cephalic dorsum denser than on rest of body; petiolar node and disc of postpetiole also with posteriorly-directed decumbent simple setae; gastral tergites sparsely with long flagellant setae, erect or looped (fragile, sometimes partially abraded and appear as hooked or apically-curved simple 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 and 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; mandibles 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 (anepisternum sometimes also sculptured), with vestiges of sculpture around margins. Basigastral costulae short, around one fourth in length of first gastral tergite; rest of gaster smooth and shining.

Comments

Strumigenys scutica sp. nov. is a member of Subgroup B in the S. godeffroyi -group and shares all its characters ( Bolton 2000), but cannot be further assigned to any existing species complex within the group. It can be confidently stated that S. scutica does not belong to the rofocala -complex, for its pronotal humeral seta is simple (instead of long and flagellate). Strumigenys scutica has flagellate setae on the gastral tergites, which conflicts with the current diagnosis of the signeae -complex.

Aside from Strumigenys scutica sp. nov., there are ten other species from the signeae -complex ( S. ahares Bolton, 2000 , S. forficata Brown, 1959 , S. izepara Bolton, 2000 , S. mailei Wilson & Taylor, 1967 , S. praefecta Bolton, 2000 , S. signeae Forel, 1905 , S. sublaminata Brown, 1959 , S. uichancoi Brown, 1957 , S. valefor Bolton, 2000 and S. virgila Bolton, 2000 ) that also have their side of the propodeum at least partially smooth and shining ( Table 10 ). For S. scutica , its mandible is curvilinear, narrow and without carina on the inner margin (unlike S. ahares , S. forficata or S. signeae , for the first two species have non-curvilinear mandibles, while the latter two species have carina on the inner margin of the mandible); a pronotal humeral seta is present (unlike in S. forficata or S. praefecta ); the pronotum is sculptured (unlike in S. forficata , S. izepara or S. uichancoi ); the propodeal lamella is broad (instead of narrow lamella as in S. izepara , or just a narrow carina as in S. mailei or S. praefecta ); the lateral lobe of the petiole is small in profile view (instead of large and extensive as in S. virgila ). Strumigenys scutica lacks the characteristic spatulatiform pilosity on the cephalic dorsum of S. sublaminata , or remiform setae on the mesonotum of S. valefor . Strumigenys scutica also has a relatively longer mandible (MI 44–49) than S. forficata (MI 35) or S. virgila (MI 36–38), and longer scape (SI 80–88) than S. izepara (SI 67) or S. sublaminata (SI 62–69).

Geographic range

Mainland China (Hainan).

Ecology

Collected in primary forest.

Figures

Fig. 37. Holotype worker (ANTWEB1011923) of Strumigenys scutica sp. nov. A. Full-face view. B. Profile view. C. Dorsal view.