Strumigenys doydeei, 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 : 42-46

Strumigenys doydeei sp. nov.

urn:lsid:zoobank.org:act:D7B231A9-7917-4DAA-ADD7-507635F5054D

Figs 13–15 ; Tables 2 , 6

Diagnosis

Strumigenys doydeei sp. nov. can be distinguished from other species in the S. leptothrix -group by a combination of the following characters: cephalic dorsum with appressed plank-like to spatulate setae; without laterally-projecting seta (at most 1–2 at occipital corner); in profile view, cephalic dorsum without any standing seta; pronotum marginated dorsolaterally; propodeal spines subtended by broad lamellae; femora, tibiae and basitarsi with long erect setae.

Etymology

The species is named after Dr Puvadol Doydee for his support, kindness and hospitality during our journeys to Thailand. 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. 13 )

VIETNAM • Đắk Nông Province, Nam Nung Reserve, Site 58 ; 12.17344° N, 107.77545° E; 895 m a.s.l.; 10 Jun. 2018; IBBL members leg.; Winkler; rubber plantation; LKCNHM ANTWEB1010892 (collection code IBBL NN-S58-sp01).

Paratype workers

VIETNAM • 6 workers; same collection data as for holotype; HKBM ANTWEB1010893 to ANTWEB1010898 (collection code IBBL NN-S58-sp01) .

Paratype queen ( Fig. 14 )

VIETNAM • 1 alate queen; Đắk Nông Province , Nam Nung Reserve, Site 61; 12.17373° N, 107.76215° E; 905 m a.s.l.; 10 Jun. 2018; IBBL members leg.; Winkler; rubber plantation; LKCNHM ANTWEB1010899 (collection code IBBL NN-S61-sp16) .

Additional material examined

VIETNAM – Đắk Nông Province • 1 worker; Nam Nung Reserve , Site 61; 12.17373° N, 107.76215° E; 905 m a.s.l.; 10 Jun. 2018; IBBL members leg.; Winkler; IBBL • 14 workers; Nam Nung Reserve , Site 60; 12.17097° N, 107.7708° E; 912 m a.s.l.; 10 Jun. 2018; IBBL members leg.; Winkler; IBBL • 1 worker, 1 queen; Nam Nung Reserve , Site 62; 12.1731° N, 107.76395° E; 902 m a.s.l.; 10 Jun. 2018; IBBL members leg.; Winkler; IBBL .

Measurements

Holotype worker

TL 2.6, HL 0.65, HW 0.47, MandL 0.10, SL 0.33, EL 0.079, PW 0.25, ML 0.62, PL 0.32, PH 0.14, DPW 0.09, PPL 0.17, GL 0.72, CI 73, MI 16, SI 69, OI 17, LPI 43, DPI 28.

Paratype workers

TL 2.4–2.7, HL 0.60–0.65, HW 0.44–0.47, MandL 0.09–0.10, SL 0.30–0.32, EL 0.066 –0.076, PW 0.23– 0.27, ML 0.59–0.66, PL 0.29–0.37, PH 0.12–0.14, DPW 0.09–0.12, PPL 0.18–0.22, GL 0.65–0.75, CI 72–75, MI 13–16, SI 66–70, OI 15–17, LPI 38–47, DPI 29–32 (n=6).

Paratype queen

TL 3.1, HL 0.68, HW 0.54, MandL 0.15, SL 0.33, EL 0.136, PW 0.39, ML 0.85, PL 0.38, PH 0.18, DPW 0.12, PPL 0.20, GL 0.87, CI 79, MI 22, SI 62, OI 25, LPI 48, DPI 32 (n= 1).

Worker description

HEAD. In full-face view, occipital margin deeply concave; occipital corners well developed and bluntly angular; occipital carina broad. 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; basal lamellae low and broadly triangular, not fully visible at full closure. In profile view, eye with four ommatidia in diameter.

DENTITION ( Fig. 13B ). Principal dental row with eight alternating short triangular and long spiniform teeth (i.e., four consecutive pairs of teeth, each pair consists of short tooth followed by long tooth), second and third pairs subequal in size and longer than other pairs (short tooth of one pair compares with short tooth of another pair only, same for long tooth); followed by 3–4 small teeth and, at down curvature in anterior view, series of four minute denticles, terminating in small apical tooth. Total dental count of 16–17.

MESOSOMA. In profile view, mesosomal dorsum broadly convex; pronotum marginated dorsolaterally. In dorsal view, lateral margins of the pronotum evenly convex. In profile view, propodeal spines elongated-triangular, subtended on each side by broad lamella with deeply concave posterior margin that broadens basally into rounded convex propodeal lobe. 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 two times as long; disc of postpetiole slightly broader than long, around 1.1–1.2 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 anterior margin.

PILOSITY. In full-face view, cephalic dorsum with appressed spatulatiform setae, ranging from plank-like setae near occipital margin to spatulate setae near posterior clypeal margin; clypeal dorsum covered with short spatulate to elliptic setae; mandibular dorsum covered with small oblanceolate setae; masticatory margins each with row of medially-directed fine setae. Head without any laterally-projecting seta, at most 1–2 at the occipital corner; decumbent setae present along dorsolateral margin of head, those along lateral margin of occipital lobe overlap with one another. Surface of scape covered with appressed subspatulate setae; funiculus (except for apical antennomere) covered with appressed acicular setae; progressively finer setae densely covering apical antennomere. In dorsal view, promesonotal dorsum sparsely with appressed subspatulate setae; posteriorly-directed decumbent setae present along lateral margins; petiolar node and disc of postpetiole sparsely with appressed setae. Pronotal humeral seta straight and stout, longer than other setae on pronotal dorsum. In profile view, cephalic dorsum without any erect seta; erect stout setae present on mesonotal dorsum as three pairs, on petiole, on disc of postpetiole, and all over gastral tergites; ventral surface of head with decumbent setae; gastral sternites sparsely with suberect to decumbent setae. Hairwheel present at mesopleural excavation. 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 densely areolate-rugulose; surface of antennal scrobe, antenna and legs densely areolate. Promesonotal dorsum predominantly densely areolate, with weak longitudinal rugulae and long, weak, longitudinal median striation; propodeal dorsum and dorsum of petiolar node densely areolate-rugulose. Side of pronotum mostly smooth and shining, weakly areolate-rugulose around margins; pleurae and side of propodeum densely areolate-rugulose. Disc of postpetiole smooth and shining. Basigastral costulae short, around one fifth in length of first gastral tergite; rest of gaster smooth and shining.

Queen description

Similar in all points to worker caste except for reproductive caste morphological characters (presence of 3 ocelli, enlarged eyes and thorax), and following: center of anepisternum and katepisternum each with patch of surface smooth and shining; promesonotal dorsum in profile densely covered with decumbent to appressed setae; petiolar node higher than in worker caste.

Comments

Strumigenys doydeei sp. nov. is a member of elegantula -complex in the S. leptothrix -group and shares all its characters ( Bolton 2000).

Aside from Strumigenys doydeei sp. nov., there are five other SEA species from the same species group ( S. decumbens sp. nov., S. japonica , S. megaera , S. rongi sp. nov. and S. scolopax ) that share the following characters: cephalic dorsum covered with appressed spatulatiform (elliptic, plank-like, linear, subspatulate, spatulate, oblanceolate, obovate or ovate) setae only, head without laterally-projecting seta in full-face view (at most limited to 1–2 at occipital corner for S. doydeei ) ( Table 6 ). Unlike the three existing species and S. rongi , for S. decumbens and S. doydeei the propodeal spines are subtended by broad lamellae (instead of narrow lamellae or carinae).

Strumigenys doydeei sp. nov. shares a very similar cephalic pilosity with S. decumbens sp. nov., though unlike S. decumbens , these appressed setae are generally more consistent in shape across the cephalic dorsum (instead of markedly transit from spatulate to plank-like setae towards the occipital margin). Strumigenys doydeei also has laterally-projecting setae on the middle and hind femora, tibiae and tarsi (instead of decumbent to appressed setae only as in S. decumbens ). See comments under S. intermedia sp. nov. for a detailed comparison between the newly described species and the existing species from S. leptothrix -group.

Specimens from Yunnan Province of mainland China (CASENT0715042–CASENT0715045) ( Fig. 15D– F ) and Chaiyaphum Province of Thailand (CASENT0285186) ( Fig. 15A–C ) that were previously reported as S. ailaoshana and S. elegantula , respectively, are now re-identified as S. cf. doydeei instead based on specimen photos. The Yunnan specimen has narrower setae on its antennae than specimens from elsewhere (acicular vs subspatulate), no other morphological difference is observed. The Thai specimen appears to be smaller than the specimens from Vietnam. With the records from Yunnan Province of mainland China, central Thailand and southern Vietnam, this species is likely widely distributed within the Indochinese Peninsula. Future records in Cambodia and Laos seem likely.

Geographic range

Mainland China (Yunnan), Thailand (Chaiyaphum), Vietnam (Đắk Nông).

Ecology

Collected in rubber plantations at elevations from 895 to 912 m.

Figures

Fig. 13. Type specimens ofStrumigenys doydeei sp. nov.A, C–D. Holotype worker (ANTWEB1010892). B. Paratype worker (ANTWEB1010897). A. Full-face view. B. Mandible close-up. C. Profile view. D. Dorsal view.

Fig. 14. Paratype queen (ANTWEB1010899) of Strumigenys doydeei sp. nov. A. Full-face view. B. Profile view. C. Dorsal view.

Fig. 15. Workers of Strumigenys cf. doydeei sp. nov. in full-face, profile and dorsal views. A–C. Worker from Thailand (CASENT0285186, taken by Cong Liu). D–F. Worker from Yunnan, mainland China (CASENT0715043, taken by Takumi Uchima, Environmental Science Section, OIST).