Myopias suwannaphaki, Jaitrong & Wiwatwitaya & Yamane, 2020

Jaitrong, Weeyawat, Wiwatwitaya, Decha & Yamane, Seiki, 2020, Three new species of the ant genus Myopias Roger, 1861 (Hymenoptera: Formicidae: Ponerinae) from Borneo, Raffles Bulletin of Zoology 68, pp. 608-618 : 614-615

Myopias suwannaphaki , new species

( Figs. 4 , 5 )

Types. Holotype: worker (BOR-JWY-16, UMS), East Malaysia, Borneo, Sabah, Maliau Basin , buffer zone, leaf litter, 270–300 m alt., 19 November 2011, coll. Sk. Yamane, SB 11-SKY-39 . Paratypes: seven workers (BOR-JWY-17

to BOR-JWY-23, SKYC), and two workers (BOR-JWY-24 and BOR-JWY-25, THNHM), same data as holotype ; two dealate gynes (BOR-JWY-26, THNHM; and BOR-JWY-27, SKYC), same data as holotype .

Non-type material examined. Two workers, East Malaysia, Borneo , Sabah, Kinabalu Park , Poring (600 m alt.), 10 November 1996 , coll. T. Kikuta; one worker, Danum Valley , 28 August 1995, coll. H. Okido.

Worker Description ( Fig. 4 )

Measurements. Holotype: TL 2.90, HL 0.59, HW 0.48, SL 0.40, ED 0.03, ML 0.36, PW 0.40, MSL 0.83, PL 0.23, PH 0.33, DPW 0.30; CI 81, SI 83, OI 7, MI 61, LPI 143, DPI 129. Paratypes (n = 5): TL 2.87–2.94, HL 0.56–0.63, HW 0.40–0.46, SL 0.36–0.40, ED 0.03–0.07, ML 0.33–0.40, PW 0.33–0.40, MSL 0.79–0.83, PL 0.23–0.26, PH 0.30–0.33, DPW 0.26–0.30; CI 67–78, SI 79–100, OI 7–14, MI 56–71, LPI 125–143, DPI 100–114.

Head. In full-face view, head clearly longer than broad (CI = 79–81) (longer than broad even excluding median clypeal lobe), subrectangular with sides weakly convex and posterior margin weakly concave; posterolateral corner of head bluntly angulate. Frontal lobe short, almost as long as median clypeal lobe, slightly translucent. Median longitudinal frontal sulcus deep, extending slightly beyond ⅓ of head length. Median clypeal lobe narrow, clearly longer than broad, slightly broader anteriorly, its anterior margin weakly convex. Mandible robustly linear and subfalcate, relatively short, in profile view down-curved; masticatory margin with three teeth, i.e., large basal tooth, large prebasal tooth, and sharp apical tooth; basal margin entire. Eye very small, with ca. 4–5 ommatidia. Antennal scape robust and gradually widened toward apex to approximate width of frontal lobe, not reaching posterior margin of head; antennal segment II longer than broad and longer than each of segments III–VIII; segments III–VIII each shorter than broad; four apical segments forming a club.

Mesosoma. Stout, in profile, with weakly convex dorsal outline; mesonotum higher anteriorly than posteriorly, slightly higher than pronotum and propodeum; promesonotal suture distinct; metanotal groove indistinct or absent; mesopleuron clearly demarcated from metapleuron and mesonotum by shallow simple grooves; groove separating upper and lower portions of mesopleuron vestigial or absent; metapleuron not demarcated from lateral face of propodeum; pronotum in dorsal view slightly broader than mesonotum and propodeum; mesonotum about ⅔ length of pronotum. Propodeum in profile with almost straight dorsal outline, sloping gradually to propodeal junction; junction obtusely angulate; posterior declivity more or less flat.

Metasoma. Petiole in profile view subrectangular and sessile, higher than long, its anterior face vertical, dorsal and posterior faces weakly convex; in dorsal view, petiolar node trapezoidal, slightly broader than long (DPI 100–129), broader posteriorly; subpetiolar process well developed, subtriangular, with apex truncate and directed downward; its anterior margin convex, while posterior margin almost straight and distinctively longer than the former. Gastral segments I to V elongate; in dorsal view, segment I slightly narrower than II. Sting long, sharp and upcurved.

Body extensively smooth and shiny; dorsum of head finely punctate; antennal scape and lateral face of propodeum at least partly striate; antennal club densely microsculptured and mat. Pilosity comparatively sparse; dorsa of head, mesosoma, and metasoma with sparse standing hairs mixed with dense shorter hairs; tip of metasoma with dense standing hairs; outer faces of tibiae with sparse suberect hairs and dense appressed hairs. Body entirely reddish brown to yellowish brown, mandibles and antennal scape darker than elsewhere.

Dealate gyne description ( Fig. 5 )

Measurements. Paratypes (n = 2): TL 3.04–3.07, HL 0.66–0.69, HW 0.50, SL 0.40–0.43, ED 0.10–0.13, ML 0.36, PW 0.40, MSL 0.89–0.92, PL 0.23–0.26, PH 0.33–0.36,

DPW 0.30–0.33, CI 71–75, SI 80–87, OI 20–27, MI 52–55, LPI 125–157, DPI 113–143.

Similar to the worker in structure, sculpture, pilosity, and colouration, with the following conditions that should be noted: body clearly larger; head in full-face view rectangular, with parallel sides and straight posterior margin; punctation on dorsum of head stronger than in the worker; eye large, almost as long as apical segment of antenna; distance between eye and mandibular base much shorter than eye length; median ocellus as large as lateral ocellus; pronotum in dorsal view much broader than long; mesoscutum in dorsal view trapezoidal, broader anteriorly with anterior margin roundly convex, margined laterally with carinae that are rather strong in posterior half; in profile, its anterior portion slightly bulged and flattened caudad; parapsidal lines indistinct; mesoscutellum oblong, clearly broader than long; metanotum very short; metanotopropodeal sulcus deeply impressed; dorsal outline of propodeum almost straight; propodeal junction nearly right-angled; striation around propodeal spiracle stronger than in the worker; petiole much shorter than high compared with the worker; gaster relatively larger than in the worker.

In one gyne entire body reddish brown, in the other mesosoma and petiole much paler than head and gaster; antenna and legs yellowish brown; area along posterior margin of pronotum dark brown.

Etymology. The specific name is dedicated to Mr. Kriangkrai Suwannaphak, who is a leading specialist in entomological sciences in Thailand and helped and inspired many young biologists.

Habitat. Edge of secondary forest.

Distribution. Borneo (Sabah).

Remarks. Myopias suwannaphaki , new species, is similar to Myopias bidens ( Emery, 1900) ; M. breviloba (Wheeler, W.M., 1919) ; M. chapmani Willey & Brown, 1983 ; M. darioi Probst & Boudinot, 2015 ; M. delta Willey & Brown, 1983 ; M. emeryi ( Forel, 1913) ; M. julivora Willey & Brown, 1983 ; M. luoba Xu, Z. & Liu, 2012 ; M. mayri (Donisthorpe, 1932) ; M. minima Jaitrong, Tasen & Guénard, 2018 ; and M. tenuis ( Emery, 1900) in the following features: 1) body entirely smooth and shiny, and reddish to yellowish brown; 2) mesosoma with almost flat or weakly convex dorsal outline in profile view, with weak metanotal groove; 3) subpetiolar process subtriangular. Myopias suwannaphaki is most similar to M. chapmani , M. darioi , and M. tenuis in having a long and narrow median clypeal lobe with its anterior margin convex. However, M. suwannaphaki is easily separated from M. darioi by the size of eye in the worker caste (eye larger in M. suwannaphaki , with ca. 4–5 ommatidia; present but indistinct in M. darioi ) and mandibular dentition (masticatory margin with three teeth in M. suwannaphaki ; four teeth in M. darioi ). Myopias suwannaphaki is separated from M. chapmani by a shorter antennal scape, not reaching posterior margin of head in M. suwannaphaki (extending beyond posterior margin of head in M. chapmani ), and the propodeum being extensively smooth and shiny in M. suwannaphaki (entirely reticulate in M. chapmani ). Myopias suwannaphaki can be distinguished from M. tenuis by indistinct metanotal groove (sometimes even absent) in M. suwannaphaki (distinct in M. tenuis ), and the petiolar node shorter than broad in M. suwannaphaki (as long as or slightly longer than broad in M. tenuis ). Two specimens (CASENT0179634 and CASENT0179634-D01; images available on AntWeb), collected from Malaysia, Sabah, Maliau Basin, 4°49′49″N, 116°54′1″E, 21 November 2007, by Noel Tawatao (NT163) from litter in a rainforest with a Winkler bag, have been identified as Myopias my01. Images of these specimens agree well with the worker of M. suwannaphaki in having a long and narrow median clypeal lobe, with its anterior margin convex. Thus, these specimens (ANTWEB CASENT0179634 and CASENT0179634-D01) can be conspecific with M. suwannaphaki .

Figures

Fig. 4. Myopias suwannaphaki, new species, worker (holotype, BOR-JWY-16, UMS). A, body in profile view; B, head in full-face view; C, body in dorsal view.

Fig. 5. Myopias suwannaphaki, new species, dealate gyne (paratype, BOR-JWY-26, THNHM). A, body in profile view; B, head in fullface view; C, body in dorsal view.