Paratopula bauhinia Luo & Guénard, 2016

Ying Y. Luo & Benoit Guénard, 2016, Descriptions of a new species and the gyne in the rarely collected arboreal genera Paratopula and Rotastruma (Hymenopytera: Formicidae) from Hong Kong, with a discussion on their ecology, Asian Myrmecology 8, pp. 1-16 : 4-8

Paratopula bauhinia Luo & Guénard , sp. nov.

PTL Petiole Length. Maximum diagonal length of petiole, measured in lateral view, from most anteroventral point of the peduncle, at or below the propodeal lobe, to most posterodorsal point at the junction with helcial tergite.

PTH Petiole Height. Maximum height of petiole, measured in lateral view from the highest (median) point of the node, orthogonally to the ventral outline of the node.

PTW Petiole Width. Maximum width of the petiole in dorsal view.

PPL Postpetiole Length. Maximum length of postpetiole, measured in lateral view.

PPH Postpetiole Height. Maximum height of postpetiole, measured in lateral view from the highest point of the node.

PPW Postpetiole Width. Maximum width of the postpetiole in dorsal view.

CI Cephalic Index. Calculated as: HW / HL ×100.

SI Scape Index. Calculated as: SL / HW ×100.

MaI Mandibular Index. Calculated as: MaL / HW ×100.

PI Petiolar Index. Calculated as: PTW / PTL ×I100

PPI Postpetiolar Index. Calculated as: PPW / PPL × 100

Abbreviations of the type depositories are as fol-

lows:

SBSHKU Insect Biodiversity and Biogeography

Laboratory, School of Biological Sciences, The

University of Hong Kong, Hong Kong SAR.

Holotype. A worker collected from HONG KONG, Lung Fu Shan Country Park, N 22.281056 E 114.137985, elevation 147m, collected by hand at approximately 20:30 h, 30.ix.2015 (Ying Y. LUO), label “ANTWEB1009012” deposited in SBSHKU.

Paratypes. Two workers collected from HONG KONG, Lung Fu Shan Country Park. One worker found at N 22.278592 E 114.13817 (approximately 275m away from where the holotype was found), elevation 272m, collected by hand at approximately 21:00 h, 06.i.2016 (Gordon YONG), label “ANTWEB1009013” deposited in SBSHKU. The second was collected near the location of the other paratype, at N 22.279139 E114.136755, elevation 273m, hand collected at approximately 21:00 h, 21.iv.2016 (Ying Y. LUO), label “ANTWEB1009014” deposited at SBSHKU.

Worker description

Holotype. HL 1.34 mm; HW 1.13 mm; MaL 0.68 mm; SL 0.92 mm; EL 0.29 mm; WL 1.90 mm; PNW 0.84 mm; PNH 0.66 mm; MW 0.45 mm; SPL 0.50 mm; PTL 0.84 mm; PTW 0.45 mm; PTH 0.44 mm; TL 6.40 mm; PPL 0.50 mm; PPW 0.56 mm; PPH 0.48 mm; CI 84; SI 81; MaI 61; PI 54; PPI 112

Paratype s (n=2). HL 1.29-1.31 mm; HW 1.08- 1.10 mm; MaL 0.60-0.65 mm; SL 0.90-0.92 mm; EL 0.26-0.30 mm; WL 1.73-1.84 mm; PNW 0.75- 0.78 mm; PNH 0.58-0.60 mm; MW 0.41-0.42 mm; SPL 0.47 mm; PTL 0.78-0.82 mm; PTW 0.39-0.41 mm; PTH 0.35-0.41 mm; TL 6.21-6.78 mm; PPL 0.44-0.45 mm; PPW 0.52-0.54 mm; PPH 0.43-0.45 mm; CI 84-86; SI 84; MaI 56 -60; PI 50; PPI 116-123

Head. In full face view, head longer than broad (CI 84-86), rectangular in shape (Figure 1). Occipital margin with median portion slightly concave. Posterior corners of head rounded. Sides of head straight and parallel. Eyes oval-shaped, in the longest dimension with a dozen ommatidia and located roughly anterior to the midpoint of the head. Antennal insertion covered by frontal lobes. Frontal carinae extending from the frontal lobes and nearly reaching the posterior margin of head; roughly as long as the scape. Parallel lines of faintly reticulate rugae present between the frontal carinae. Anterior clypeal margin convex with anteromedian portion slightly concave. Mandibles short relative to head (MaI 56 -61).

Mandibles large and triangular, with masticatory margin armed with 10 teeth (Figure 2). Apical tooth large and acute followed by smaller triangular teeth decreasing in size progressively. Mandibles with fine appressed hairs, with a few decumbent hairs present on the apical margin of mandibles and oriented ventrally. Antenna with 12 segments and terminated by an incrassate 3-segmented club. In profile view, scape slightly bent and slightly increasing in diameter from base to apex. In full face view, antennal scapes not reaching the occipital margin (SI 81-84).

Mesosoma. In profile view, promesonotum slightly convex (Figure 3). In dorsal view, pronotal humeri round in appearance, pronotum broad- er than long with its anteromedian portion convex and progressively rounded (Figure 4). Promesonotal suture clearly visible in profile view but indistinct in dorsal view. Metanotal groove conspicuous in profile and dorsal view. In profile view, metanotal groove deeper than half of length of the longest hair present on the dorsal surface of the propodeum. In profile view, propodeal declivity forming a 120° angle with the dorsal surface of propodeum. Propodeal spines straight and well developed, not extending beyond the propodeal lobes. When viewed dorsally, propodeal spines are rounded blunt in appearance, and not tapering. Propodeal spiracle opening conspicuous and round in shape. Propodeal lobes developed and broadly rounded.

Metasoma. In profile, peduncle of petiole long, ventrally with a small denticle near base. In profile, petiole node roughly trapezoidal in shape, and dorsum of postpetiole broadly convex. Anterior 2/3 of subpostpetiolar process margin convex when viewed in profile. In dorsal view, petiole roughly oval in shape (Figure 5), longer than broad (PI 50-54). Postpetiole broader than long (PPI 112-123), more narrow at the anterior edge than the posterior edge, roughly trapezoidal in shape. Gaster not sculptured (smooth), with short hairs present. First gastral tergite large, covering 2/3 of the gaster with longitudinal striae at the base.

Sculpture. Cuticle thick, strongly sculptured on all surfaces except the antenna, legs, peduncle of petiole and gaster. Frons with parallel, faintly reticulate rugae.

Pubescence. All dorsal surfaces (except peduncle) with short, erect, acute hairs, gold in colour. Hairs on first gastral tergite and dorsal surfaces of the head, mesosoma and metasoma acute and almost spearlike in appearance. Subpostpetiolar process with a few thin erect hairs. Antenna covered in short appressed hairs, with additional short sub-erect hairs present.

Colouration. Body relatively uniform in golden-brown colour, legs lighter in colouration. Apical portion of mandibles with darker reddish coloration.

Castes. Female and male caste unknown.

Etymology

This species is named after the genus of the tree species Bauhinia blakeana Dunn, also known as the Hong Kong Orchid Tree, an emblem of Hong Kong. The flower of Bauhinia blakeana appears on the Hong Kong flag, and is commonly known by Hong Kong inhabitants as the “ Bauhinia ”, which refers to the type locality of the new Paratopula species described. It also indirectly refers to the suspected arboreal habits of the new species. The name is a noun and is thus invariant.

Distribution

This species is known only from the type localities, both located in Lung Fu Shan Country Park, on Hong Kong Island in Hong Kong.

Ecology

The holotype specimen of P. bauhinia was found foraging in sparse leaf litter on a man-made concrete structure raised at about 1.8m above ground level (see Figure 6), and located under the tree species Syzygium jambos Alston and Litsea monopetala Persoon. The surrounding habitat is the edge of a young secondary forest close to a well-used hiking trail in Lung Fu Shan Country Park, Hong Kong. It was found at approximately 20:30 h.

Both paratype specimens were found approximately 275m further up the trail, on a railing adjacent to the concrete hiking trail (see Figure 6). This part of the trail is surrounded by a monoculture plantation of the tree Lophostemon confertus Wilson & Waterh. They were both found at approximately 21:00h at three months interval.

Remarks

Two other species of Paratopula have been recorded in China: P. zhengi and P. ceylonica , but P. bauhinia is morphologically distinct from these two species. The propodeal spines of P. bauhinia are distinct to those of P. zhengi and P. ceylonica ; in P. bauhinia the propodeal spines are straight and apically truncate, while the propodeal spines of P. zhengi are described as “slender and acute, slightly curved upwards apically” (Figure 2 in Xu & Xu 2011). In P. ceylonica , the propodeal spines are described as being “straight to very feebly down curved” ( Bolton 1988) in profile view - examination of the type specimen (CASENT0908985) on Antweb.org, confirms this. The hairs on the dorsum of P. zhengi are also described as “short blunt erect hairs”, but in P. bauhinia the hairs are apically acute. Additionally, the postpetiole of P. ceylonica is squarish in appearance (see Figure 5 in Bolton 1988) in dorsal view, whereas in P. bauhinia the postpetiole is broader than long, appearing roughly trapezoidal.

Paratopula bauhinia differs from P. catocha in that P. bauhinia has a trapezoidal shaped postpetiole when viewed dorsally, whereas P. catocha has a round shaped postpetiole when viewed dorsally (see Figure 4 in Bolton 1998). Paratopula catocha is described to only have 8-9 teeth ( Bolton 1988), while P. bauhinia has 10 teeth. Additionally, P. catocha has been recorded only from Sulawesi (antmaps.org) and thus its presence in Hong Kong seems rather unlikely.

When comparing P. bauhinia and P. demeta , the most conspicuous differences can be observed in the dorsal view. In dorsal view the median portion of the anterior margin of the pronotum is angular in P. demeta , whereas in P. bauhinia the margin in broadly rounded. Paratopula demeta also has angular pronotal humeri, but P. bauhinia has rounded pronotal humeri (Figure 8). Additionally, the pubescence of P. bauhinia differs to P. demeta , in P. bauhinia the hairs are apically acute while in P. demeta the hairs are apically truncated.

In Eguchi et al. (2011) there is mention of an unidentified Paratopula worker (labelled as Paratopula sp, eg-1) found in Nam Cat Tien, Vietnam. While it is difficult to conclude what species this specimen may be, it is distinct from P. bauhinia in that it has 9 teeth, and based on the pictures the propodeal spines appear to be much longer than P. bauhinia ; extending beyond the propodeal lobes (see Figure 112 and text in Eguchi et al. 2011). Hairs of Paratopula sp. eg-1 are also described as “short and blunt apically” ( Eguchi et al. 2011), while the hairs of P. bauhinia are apically acute.

Paratopula bauhinia is distinct from other species of Paratopula in that no other species is described as having the following combination of features: 10 teeth on the masticatory margin of the mandibles, apically acute hairs, a rounded median portion of the anterior margin of the pronotum, a broader than long postpetiole and straight, blunt propodeal spines. These features, combined with other characteristics establishes P. bauhinia as a unique species within this genus.