Strumigenys yamanei, 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 : 123-125

Strumigenys yamanei sp. nov.

urn:lsid:zoobank.org:act:041DBC07-AF41-4A33-A8E3-6ABAA882DE0F

Fig. 41 ; Tables 2 , 6

Diagnosis

Strumigenys yamanei sp. nov. can be distinguished from other species in the S. leptothrix -group by a combination of the following characters: clypeal and mandibular dorsum with small appressed obovate setae; cephalic dorsum relatively weakly reticulate-rugulose, fainter around vertex; in profile view, long erect setae present on cephalic dorsum, promesonotal dorsum, petiolar node, disc of postpetiole and gaster; mesosoma, front coxa and femur mostly 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 Seiki Yamane in recognition of his remarkable work on ants and other Hymenoptera in Asia, and his kindness in sending us specimens that led to the recognition of this new species. The name was created by adding the singular Latin genitive case suffix -i to the last name of a male person.

Type material

Holotype worker ( Fig. 41 )

TAIWAN • Chiayi, Alishan, Shuisheliao ; 1200 m a.s.l.; 4 Jul. 2017; Sk. Yamane leg.; hand collection; NMNS ANTWEB1010901 (collection code KUM TW17 -SKY-21).

Paratype workers

TAIWAN • 2 workers;same collection data as for holotype; KUM ANTWEB1010900 , ANTWEB1010902 (collection code KUM TW17 -SKY-21) .

Measurements

Holotype worker

TL 2.9, HL 0.67, HW 0.45, MandL 0.08, SL 0.33, EL 0.086, PW 0.27, ML 0.74, PL 0.33, PH 0.16, DPW 0.16, PPL 0.17, GL 0.90, CI 67, MI 12, SI 74, OI 19, LPI 48, DPI 48.

Paratype workers

TL 2.9–3.0, HL 0.71, HW 0.47, MandL 0.09–0.10, SL 0.36–0.37, EL 0.090 –0.101, PW 0.27–0.29, ML 0.75–0.76, PL 0.34–0.36, PH 0.15–0.16, DPW 0.16, PPL 0.19–0.21, GL 0.83–0.86, CI 67, MI 12–14, SI 76–78, OI 19–21, LPI 44–45, DPI 45–48 (n =2).

Worker description

HEAD. In full-face view, occipital margin broadly, shallowly concave; occipital corners well developed; occipital carina present; dorsolateral margin of head broadly convex, lateral margin of occipital lobe and upper scrobe margin not forming blunt angle. Clypeus slightly broader than long, around 1.1–1.2 times as long, roughly resembling inverted diamond; anterolateral angles of clypeus roughly semicircular. 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 broadly convex; propodeum more or less flat transversely, anterior part of propodeum with small bump; pronotum not marginated dorsolaterally. In dorsal view, lateral margins of pronotum evenly convex. In profile view, propodeal spines elongated-triangular, subtended on each side by broad lamella with concave posterior margin that broadens slightly basally into small rounded convex propodeal lobe. Metapleural gland bulla well developed.

METASOMA. In profile view, petiolar peduncle not grading evenly into node; petiolar node with differentiated anterior face, but short and inconspicuous; petiolar node with broadly convex posterior face; petiolar peduncle about as long as (or slightly longer than) node. In dorsal view, petiolar node slightly longer than broad, around 1.1 times as long; disc of postpetiole broader than long, around 1.5–1.6 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; in dorsal view, processes present along lateral and posterior margins of petiolar node, and surrounding disc of postpetiole, thicker along lateral margins than on anterior or posterior margins.

PILOSITY. Surface of antennae (except for apical antennomere) with appressed stout to acicular setae; progressively finer setae densely covering apical antennomere; clypeal and mandibular dorsum densely covered with small obovate setae; masticatory margins each with row of medially-directed fine setae; except for a few subspatulate setae close to posterior clypeal margin, appressed seta absents on rest of cephalic dorsum. Leading edge of scapes with decumbent setae. In full-face view, dorsolateral margin of head with numerous laterally-projecting setae. Pronotal humeral seta long and stout. In profile view, long erect setae present on cephalic dorsum, promesonotal dorsum, petiolar node, disc of postpetiole and dorsal surface of gaster; shorter suberect setae present on gastral sternites; ventral surface of head with appressed to decumbent setae. Hairwheel present at mesopleural excavation. Surfaces of middle and hind femora, tibiae and basitarsi with long stout erect setae.

SCULPTURE. Clypeal and mandibular dorsum smooth and shining; cephalic dorsum mostly smooth and shining, relatively weakly vertically reticulate-rugulose on the cephalic dorsum, fainter around vertex and stronger along periphery, especially towards posterior clypeal margin; surface of antennal scrobe, antenna and legs (except front coxa and femur) densely areolate. Front coxa and femur mostly smooth and shining, with relatively weak areolate close to trochanter. Mesosoma and disc of postpetiole mostly smooth and shining, with very weak longitudinal rugulae on the dorsum of mesonotum and propodeum. Dorsum of petiolar node transversely reticulate-rugulose. Basigastral costulae short, around one fifth in length of first gastral tergite; rest of gaster smooth and shining.

Comments

Strumigenys yamanei sp. nov. is a member of the S. leptothrix -group and shares all its characters ( Bolton 2000), and very likely belongs to the leptothrix -complex. The type specimens all have fully-closed mandibles and the view is obscured by setae along the inner margin of the mandible, making an accurate assessment of the dentition difficult. Placing the specimen against backlight suggests the presence of a principal dental row of around 7 teeth, followed by a series of small teeth and denticles, terminating in a small apical tooth.

Strumigenys yamanei sp. nov. can be distinguished from all other SEA species of the same species group by its unique combination of clypeus and mandibles covered with appressed obovate setae, a cephalic dorsum with numerous long erect setae, a pronotum that is not marginated, propodeal spines present and subtended by broad lamellae ( Table 6 ). In contrast, other species that have long suberect to erect setae only on the cephalic dorsum ( S. jacobsoni , S. leptothrix , S. medusa , S. scylla , S. stheno and S. strummeri sp. nov.) lack appressed obovate setae on the clypeus, or do not have a smooth, unsculptured pronotal dorsum.

Geographic range

Taiwan.

Ecology

Collected in forest at elevation of 1200 m.

Figures

Fig. 41. Holotype worker (ANTWEB1010901) of Strumigenys yamanei sp. nov. A. Full-face view. B. Profile view. C. Dorsal view.