Opamyrma hungvuong

Opamyrma hungvuong
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Hymenoptera
Family:	Formicidae
Subfamily:	Leptanillinae
Genus:	Opamyrma
Species:	O. hungvuong
Binomial name
	Opamyrma hungvuong; Yamane, Bui & Eguchi, 2008 Specimen Label

Opamyrma hungvuong, the only species known from the genus, feeds on selected geophilomorph (Mecistocephalus sp.), lithobiomorph (Lithobius sp.) and juvenile scolopendromorph centipedes (Scolopocryptops sp.). Not only workers but also alate and dealate queens aggressively attack centipedes. However, they failed to hunt linotaeniid geophilomorph centipedes (Strigamia sp.), being quickly killed probably due to the chemical defense of the centipede. Workers and dealate queens show eager (apparently hemolymph) licking behavior on paralyzed Mecistocephalus centipede. Additional observations by Yamada et al. (2023) indicate that O. hungvuong is well-adapted for preying on certain active centipedes, although their exact prey repertoire and degree of prey specialization remain uncertain.

Photo Gallery

Yamada et al., 2023, Fig. 1. Habitat and the collecting site of Opamyrma hungvuong. (A) workers of O. hungvuong photographed on excavated soil, colony EG20230318-783; (B) evergreen forest on the mountain slope in Pu Hoat Nature Reserve (Nghe An, Vietnam) where the two colonies and the solitary dealate queen were collected; (C) excavated spot where the colony AKY21iii23-312 was collected; (D) known locality records of O. hungvuong (the present new record is indicated by a star; the type locality is indicated by a square).
Yamada et al., 2023, Fig. 3. Scenes of centipede hunting by Opamyrma hungvuong. (A, B) attacks against the Mecistocephalus geophilomorph centipede; in B, two workers are clinging to the antennae of the centipede by their mandibles and stinging or attempting to sting on the prey’s head venter (see also the alate queen connecting to the prey only via sting); (C, D) attacks against the juvenile Scolopocryptops scolopendromorph centipede; in C, three workers are grasping the centipede’s legs by mandibles and one worker stinging on the prey’s body; in D, a worker is attempting to sting the centipede’s head while clinging to the prey’s antenna.
Yamada et al., 2023, Fig. 4. Finishing scenes of solitary centipede hunting by the dealate queen of Opamyrma hungvuong (prey: juvenile Scolopocryptops), in order of time sequence (A–C); the dealate queen grasped the centipede’s antennal base by mandibles (A) and then stung the head venter while continuously holding the prey’s antenna (B, C).
Yamada et al., 2023, Fig. 5. Licking behavior of Opamyrma hungvuong workers and dealate queens on the paralyzed Mecistocephalus geophilomorph centipede. (A) workers and dealate queens licking on the pleural membranes of the centipede (black arrows); (B) worker licking on the prey’s pleural membrane in lateral view; (C) dealate queen licking the prey’s leg; (D, E) wound melanizations on the prey’s pleural membranes (indicated by red circles; E is a zoom-in view of the area indicated by the non-broken circle in D).

Identification

Yamane et al. (2008) - Opamyrma is similar to Apomyrma with several shared characteristics: the outer face of the labrum bears peglike teeth; the frontal lobe is absent; the antennal socket is directed almost dorsad; the sternite of the petiole is reduced to a small posteroventral sclerite, bounded by the conspicuous tergo-sternal sutures; and the third abdominal segment above the helcium has a free anterior face.

The features which separate Opamyrma from Apomyrma (see Brown et al 1971; Bolton 1990, 2003 for characterization of Apomyrma) are: preoccipital carina complete, almost encircling the head slightly before its posterior margin; clypeus posteriorly margined with a distinct continuous carina; petiole without a distinct anterior peduncle; abdominal segment III longer than IV, V and VI; segment VII longest among the segments III–VII; anteriormost part of abdominal sternite III produced anteriad to the same level as the anteriormost part of tergite III; segment IV with differentiated presternite.

pxGriebenow (2024), Figure 34. Abdominal segments II–III of female Leptanillinae, profile view. Abdominal tergite II outlined in red; anterior of abdominal segment III outlined in blue. A, Opamyrma hungvuong (AKY05vii17-06) (Yamada et al. 2020: fig. 1C), worker. B, Protanilla gengma (CASENT0179564), worker. C, Protanilla id01 (MCZENT00728282), gyne. Scale bars: 0.5 mm (A); 0.2 mm (B, C).
Griebenow (2024), Figure 38. Exemplars of male wing venation across the Leptanillinae, diagrammatic B, C are typological generalizations of male wing venation in the clades that they represent. A, Opamyrma hungvuong. B, Protanilla. C, Leptanilla najaphalla species group. D, Leptanilla javana. Abbreviation: pts = pterostigma.

Keys including this Species

Keys to Leptanillinae

Distribution

Central Vietnam.

Latitudinal Distribution Pattern

Latitudinal Range: 18.51666667° to 18.51666667°.


North Temperate	North Subtropical	Tropical	South Subtropical	South Temperate

Source: AntMaps

Distribution based on Regional Taxon Lists

Oriental Region: Vietnam (type locality).
Palaearctic Region: China.

Distribution based on AntMaps

Distribution based on AntWeb specimens

Check data from AntWeb

Countries Occupied

Number of countries occupied by this species based on AntWiki Regional Taxon Lists. In general, fewer countries occupied indicates a narrower range, while more countries indicates a more widespread species.

Estimated Abundance

Relative abundance based on number of AntMaps records per species (this species within the purple bar). Fewer records (to the left) indicates a less abundant/encountered species while more records (to the right) indicates more abundant/encountered species.

Biology

Castes

Photo Gallery

Opamyrma hungvuong worker (1–3) and queen (4–6) (Specimen No. G160941, from Chen, Z.-L., Shi F.-M. et al., 2017.)

Images from AntWeb


Holotype of Opamyrma hungvuong. Worker. Specimen code casent0178347. Photographer April Nobile, uploaded by California Academy of Sciences.

Nomenclature

The following information is derived from Barry Bolton's Online Catalogue of the Ants of the World.

hungvuong. Opamyrma hungvuong Yamane, Bui & Eguchi, 2008: 57, figs. 1-12 (w.) VIETNAM.

Unless otherwise noted the text for the remainder of this section is reported from the publication that includes the original description.

Description

Worker

Measurements and indices (holotype and paratype; those for paratype shown in parentheses). Head length (as measured from the anterior margin of clypeus to the posterior margin of head in full-face view) 0.73 mm (0.71); head width (maximum width of head in full-face view) 0.55 mm (0.55); cephalic index (head width/head length x 100) 75 (77); scape length (length of antennal scape excluding the basal condylar bulb) 0.38 mm (0.38); scape index (scape length/head width x 100) 69 (69); mesosomal length (as measured from the anterior margin of pronotum to the posterior margin of propodeum in profile) 1.12 mm (1.12); hind femur length (maximum length of hind femur) 0.50 mm (0.49); hind femur index (hind femur length/head width) 91 (89).

Head long, almost rectangular, with slightly convex lateral margins and almost straight posterior margin in full-face view; in profile flattened dorsoventrally. Median part of clypeus with anterior margin weakly and broadly concave. Mandible slender, strongly curved at the apical end of trulleum (this can be clearly observed when the mandibles are opened); basal two-thirds almost parallel-sided in outer view (Fig. 5), with long but bluntly tapered apical tooth followed by a trapezoidal lobe (probably fusion of two preapical teeth: “mtl” in Fig. 3) and three inconspicuous teeth. Antennal scape (segment I) flattened dorsoventrally, narrowed toward base; segment II bead-like, in frontal view strongly narrowed at base (“as-II” in Fig. 2); segment III slightly longer than broad and narrowed basally; segments IV and V almost as long as broad; segments VI–XI broader than long; apical segment longer than broad and bluntly pointed at apex.

Pronotum longer than broad in dorsal view, with slightly convex dorsal face that merges into lateral face roundly; anterior slope short and steep. Remaining portion of mesosoma slightly narrower than pronotum and almost parallel-sided in dorsal view; nota and pleura roundly continuous; mesopleuron separated from metapleuron by a sulcus; lower portion of metapleuron defined posteriorly by a narrow furrow; propodeum with rather flat dorsum and steep posterior face.

Femur and tibia of fore leg broader than those of mid- and hind legs; relatively broad gap present between mid- and hind coxae.

Petiole seen from above much longer than broad, slightly narrowed posteriad, and laterally weakly convex, in profile much longer than high, weakly converging posteriad.

Gaster with a long and up-curved sting.

Whole body only weakly sculptured and moderately shining; mandible with sparse large punctures which generally bear setae; dorsum of head superficially punctate; clypeus with posterior portion almost unsculptured and shining; mesosoma more weakly sculptured than dorsum of head, with posteroventral portion of its side irregularly sculptured; petiole and gaster almost smooth and shining.

Head with dense short hairs that are erect or suberect; mandible when closed with lower margin bearing relatively long and sparse standing hairs; antennal scape with sparse erect hairs in addition to denser short pubescence; hairs on funiculus generally short, especially on apical segments; mesosoma and petiole dorsally with sparser standing hairs; erect hairs on tibiae and tarsi shorter than those on femora; gastral terga dorsally with standing hairs that are denser than those on mesosoma; gastral sterna each with isolated erect hairs.

Whole body light brown, with antennae and legs slightly yellowish.

Type Material

Holotype (worker): 21 Feb. 2000, Rao An, Son Kim II Commune (18°31'N; 105°27'E), Huong Son District, Ha Tinh Province, northern part of Central Vietnam, leg. T.V. Bui (Entomological Collection of the Institute of Ecology and Biological Resources). Paratype: 1 worker, same data as in the holotype (KMNH).

Etymology

The specific name hungvuong derives from the legendary king Hung Vuong who founded the first Vietnamese state Van Lang.

References