ASIAN MYRMECOLOGY Volume 8, 1 – 16, 2016
ISSN 1985-1944 © Ying Y. Luo and Benoit Guénard

DOI: 10.20362/am.008016

Descriptions of a new species and the gyne in the rarely collectedarboreal genera Paratopula and Rotastruma (Hymenoptera:
Formicidae) from Hong Kong, with a discussion on their ecology
Ying Y. Luo and Benoit Guénard*
School of Biological Sciences, The University of Hong Kong, Pok Fu Lam
Road, Hong Kong
Corresponding author: zeroben@gmail.com*

ABSTRACT. Despite its relatively large size among the Myrmicinae of theIndomalayan region, collection events of Paratopula Wheeler are rare. Here
we discuss the discovery of Paratopula in Hong Kong and present Paratopula
bauhinia sp. nov as a new species. This addition brings the number of globallydescribed species for the genus to twelve species, four of which are known only
from the reproductive caste. Paratopula bauhinia sp. nov. can be distinguishedfrom previously described species by the combination of the following features:
10 teeth on the masticatory margin of mandibles, apically acute hairs, a rounded
median portion of the anterior margin of the pronotum, postpetiole broader thanlong, and straight, blunt propodeal spines. A revised key for the eight species ofParatopula known from the worker caste is provided. Additionally, the female
caste of Rotastruma stenoceps Bolton is described for the first time. The rarityof these two genera are also discussed on the basis of their potentially nocturnal
and arboreal habits.
Keywords: Paratopula bauhinia, Rotastruma stenoceps, Myrmicinae, Hong
Kong, arboreal, nocturnal, rarity
INTRODUCTION
Paratopula Wheeler is a rare genus of ants, whosetype species, P. ceylonica (Emery, 1901), wasfirst described as part of the genus Atopomyrmex
by Emery (1901), and later erected as Paratopulaby Wheeler (1919). In 1988, Bolton revised thegenus, bringing the total number of Paratopula
species at the time to nine, with four species
known only from the reproductive caste P. andamensis Forel, P. longispina Stitz, P.
oculata Smith and P. sumatrensis Forel, with P.
andamensis described only from the male caste.
Since then, two additional species have been
described, P. intermedia Sheela & Narendran(1998) from Kerala (India) and P. zhengi Xu &Xu (2011) from Xizang (China). The discovery

1 - 16 - AM8 - Descriptions of a new species and the gyne.indd 1of P. bauhinia sp. nov. from Hong Kong brings
the total number of Paratopula species to twelve.
The ecology of Paratopula remains
enigmatic due to the rarity of collection events.
In the past, three species (P. demeta Bolton
1988; P. intermedia Sheela & Narendran 1998;
P. zhengi Xu & Xu 2011) were described on
the basis of a single worker specimen only. The
rarity of Paratopula collection translates into
an absence of knowledge on the ecology of thegenus, although the genus is thought to possess
an arboreal or sub-arboreal lifestyle (Bolton
1988; Eguchi et al. 2011).
The distribution of Paratopula isrestricted to the Indomalayan biogeographic
region, with a patchy and largely incomplete
distribution ranging from Pakistan to the West

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2Ying Y. Luo & Benoit Guénard

and the Philippines to the East and from Shanghai
to Sulawesi along a North-South axis (antmaps.
org) (Janicki et al. 2016). Paratopula diversity
peaks in Borneo with five species recorded, mostother regions include a single species recordedwith the exception of the Philippines and thePeninsular Malaysia, both with three species
recorded (antmaps.org).
Rotastruma is another rarely collectedarboreal genus belonging to the same clade
as Paratopula (Ward et al. 2015). This small
genus contains only two species which exhibit alimited distribution in the Indomalayan region.
Rotastruma recava Bolton 1991 is known from
Borneo and the Malaysian Peninsula, and R.
stenoceps Bolton 1991 is reported from China(Hubei, Hunan, Guangdong, Yunnan) (antmaps.
org). The latter was described in 1991 from
Guangdong (China) on the basis of the worker
caste, with virtually no information reported
on its ecology since its original description.
Recently, during attempts to collect additional
Paratopula specimens, a single queen identified
as Rotastruma stenoceps was collected. Here, we
describe the queen of R. stenoceps from Hong
Kong, found less than 200 kilometres South East
from the site of the holotype (Bolton 1991).
We present the first record of the genus
Paratopula in Hong Kong, which also represents
a new species, P. bauhinia. A revised key to theglobal species of Paratopula based on worker
caste is provided. A description of the female casteof Rotastruma stenoceps is also included. Finally,
we address potential reasons why Paratopula andRotastruma are so scarcely collected.
MATERIAL AND METHODS
Materials and specimens examined
The type specimens for this study were handcollected, and have been deposited in the
University of Hong Kong collection, locatedwithin the School of Biological Sciences.
To confirm the new Paratopula species
and to prepare a revised species key, we referred
to previous Paratopula publications: Bolton(1988), Sheela & Narendran (1998) and Xu & Xu
(2011). Images of the holotype specimens from the1 - 16 - AM8 - Descriptions of a new species and the gyne.indd 2

genus were also examined on AntWeb.org whenavailable, for P. ankistra (CASENT0901741),
P. catocha (CASENT0901743), P. ceylonica(CASENT0908985), P. demeta (CASENT0901742)
and P. macta (CASENT0901740). New digital
images of the holotype of P. zhengi were provided
to us thanks to Dr. Zheng Hui Xu (Southwest
Forestry University, Yunnan).
For R. stenoceps, we referred to the
only available publication on the taxonomy ofRotastruma, Bolton (1991), and compared our
specimen to a worker specimen of R. stenoceps
collected in Hong Kong, which was identified
using the original description and images of theholotype on AntWeb.org (CASENT0901994).
Terminology
Worker morphological terminology follows
Bolton (2004). Queen morphological terminology
follows Serna & Mackay (2010).
Methods
The specimens were imaged with an incorporated
Leica DFC450 digital camera mounted on a
Leica M205C dissecting microscope through the
Leica Application Suite V4 software. A total of
25 to 45 images were taken per view and were
processed. For each measurement, specimens
were imaged in the optimum position to take themeasurement. Measurements of specimens weretaken in mm (accurate to 0.001mm) and rounded
to the nearest 0.01mm for presentation, using the
Measure Tools function of the Leica Application
Suite V4 software on specimen images. Images
were collated using Adobe Photoshop ver. CS6.
The following measurements andindices follow Bolton (1988), Longino (2013)
and Fischer et al (2014). The abbreviations used
are as follows:
HW

Head Width. Maximum width of head in
full-face view excluding the eyes.

HL

Head Length. Maximum length of headfrom the anterior median clypeal margin
to the median posterior margin of the
cephalic capsule measured along the
midline as a straight line.

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Fig. 1. Full face view of P. bauhinia sp. n. (holotype). Note the abundant setae on the scape.

Fig. 2. Full face view focusing on the mandibles of P. bauhinia sp. n. (holotype).

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4Ying Y. Luo & Benoit Guénard

MaL Mandible Length. Maximum length ofmandible from the anterolateral marginof clypeus at outer side of mandibularinsertion to mandibular apex.

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

SL

PTW Petiole Width. Maximum width of thepetiole in dorsal view.

Scape Length. Maximum measurable
length of scape, from the proximal pointof scape shaft, not including the condyle,to the distal end of scape.

EL

Eye Length. Maximum diameter of eye
measured in lateral view.

TL

Total Length. Maximum length of
specimen measured from the tip of themandibles to the tip of the last abdominal
segment, not including sting. Due to theposition of the specimen, total length
was measured as the sum of head length+ thorax, petiole and postpetiole length +gaster length.

WL

Weber’s Length of Mesosoma. Maximum
diagonal distance in lateral view, frombase of anterior slope of pronotum to theposterior margin of the metapleural lobe.

PNH Pronotum Height. Maximum heightof pronotum, measured in profile fromthe posterior base of the lateral sides ofpronotum, where procoxa is attached, tothe highest point of the pronotum.
PNW Pronotal Width. Maximum width of
pronotum measured in dorsal view.
MW Mesonotal Width. Maximum width of themesonotum measured in dorsal view.
SPL Propopodeal spine length. Measured fromthe tip of the propodeal spine to the closest
point on the outer rim of the propodeal
spiracle.
PTL Petiole Length. Maximum diagonal lengthof petiole, measured in lateral view, frommost anteroventral point of the peduncle,
at or below the propodeal lobe, to most
posterodorsal point at the junction withhelcial tergite.

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PPL Postpetiole Length. Maximum length of
postpetiole, measured in lateral view.
PPH Postpetiole Height. Maximum height of
postpetiole, measured in lateral view fromthe 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 follows:
SBSHKU Insect Biodiversity and Biogeography
Laboratory, School of Biological Sciences, The
University of Hong Kong, Hong Kong SAR.
RESULTS
Description of new species
Paratopula bauhinia Luo & Guénard, sp. nov.
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.

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Fig. 3. Profile view of P. bauhinia sp. n. (holotype).

Fig. 4. Dorsal view of P. bauhinia sp. n. (holotype).

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6Ying Y. Luo & Benoit Guénard

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 theholotype was found), elevation 272m, collectedby 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, handcollected 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
Paratypes (n=2). HL 1.29-1.31 mm; HW 1.081.10 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 0.750.78 mm; PNH 0.58-0.60 mm; MW 0.41-0.42mm; SPL 0.47 mm; PTL 0.78-0.82 mm; PTW
0.39-0.41 mm; PTH 0.35-0.41 mm; TL 6.21-6.78mm; 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 ofhead straight and parallel. Eyes oval-shaped, inthe 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 marginof head; roughly as long as the scape. Parallellines 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

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margin armed with 10 teeth (Figure 2). Apicaltooth 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 ofmandibles 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 frombase 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 broader 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 lengthof the longest hair present on the dorsal surface ofthe propodeum. In profile view, propodeal declivity forming a 120° angle with the dorsal surface
of propodeum. Propodeal spines straight and welldeveloped, not extending beyond the propodeal
lobes. When viewed dorsally, propodeal spines
are rounded blunt in appearance, and not tapering. Propodeal spiracle opening conspicuous andround in shape. Propodeal lobes developed andbroadly 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 thanlong (PPI 112-123), more narrow at the anterioredge than the posterior edge, roughly trapezoidal
in shape. Gaster not sculptured (smooth), withshort 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 ofpetiole and gaster. Frons with parallel, faintly reticulate rugae.

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Fig. 5. View of the petiole and postpetiole of P. bauhinia sp. n. in dorsal view (holotype).

Pubescence. All dorsal surfaces (except peduncle) with short, erect, acute hairs, gold in colour.
Hairs on first gastral tergite and dorsal surfacesof the head, mesosoma and metasoma acute andalmost 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 HongKong. The flower of Bauhinia blakeana appearson the Hong Kong flag, and is commonly known
by Hong Kong inhabitants as the “Bauhinia”,

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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 foundforaging in sparse leaf litter on a man-madeconcrete structure raised at about 1.8m above
ground level (see Figure 6), and located under thetree species Syzygium jambos Alston and Litsea
monopetala Persoon. The surrounding habitat isthe edge of a young secondary forest close to awell-used hiking trail in Lung Fu Shan Country
Park, Hong Kong. It was found at approximately
20:30 h.

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8Ying Y. Luo & Benoit Guénard

Both paratype specimens were foundapproximately 275m further up the trail, on arailing adjacent to the concrete hiking trail (seeFigure 6). This part of the trail is surrounded bya monoculture plantation of the tree Lophostemon
confertus Wilson & Waterh. They were both foundat approximately 21:00h at three months interval.
Remarks
Two other species of Paratopula have beenrecorded in China: P. zhengi and P. ceylonica,
but P. bauhinia is morphologically distinct
from these two species. The propodeal spinesof 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 - examinationof the type specimen (CASENT0908985) on
Antweb.org, confirms this. The hairs on thedorsum of P. zhengi are also described as “shortblunt erect hairs”, but in P. bauhinia the hairs areapically 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 whenviewed dorsally (see Figure 4 in Bolton 1998).
Paratopula catocha is described to only have 8-9teeth (Bolton 1988), while P. bauhinia has 10teeth. 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 canbe observed in the dorsal view. In dorsal viewthe median portion of the anterior margin of
the pronotum is angular in P. demeta, whereasin P. bauhinia the margin in broadly rounded.
Paratopula demeta also has angular pronotal
humeri, but P. bauhinia has rounded pronotal

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humeri (Figure 8). Additionally, the pubescenceof P. bauhinia differs to P. demeta, in P. bauhinia
the hairs are apically acute while in P. demeta thehairs are apically truncated.
In Eguchi et al. (2011) there is mentionof 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 fromP. bauhinia in that it has 9 teeth, and based on
the pictures the propodeal spines appear to bemuch longer than P. bauhinia; extending beyond
the propodeal lobes (see Figure 112 and text inEguchi 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 fromother species of Paratopula in that no other species
is described as having the following combinationof features: 10 teeth on the masticatory marginof the mandibles, apically acute hairs, a rounded
median portion of the anterior margin of the
pronotum, a broader than long postpetiole andstraight, blunt propodeal spines. These features,combined with other characteristics establishes P.
bauhinia as a unique species within this genus.
Synoptic species list of global Paratopula species
Paratopula andamensis Forel, 1903 (AndamanIs.) – known from male only
Paratopula ankistra Bolton, 1988 (Brunei)
Paratopula catocha Bolton, 1988 (Sulawesi)
Paratopula ceylonica Emery, 1901 (Bangladesh,
India, Myanmar, Pakistan, Sri Lanka, Taiwan)
Paratopula demeta Bolton, 1988 (Indonesia, E.
Malaysia)
Paratopula longispina Stitz, 1938 (E. Malaysia)– known from female only
Paratopula macta Bolton, 1988
Malaysia, Philippines, Thailand)(Brunei,

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Fig. 6. Locations specimens for P. bauhinia sp. n. were collected for A) the holotype and B) the two paratypes.
Arrows indicates exact location of P. bauhinia sp. n. collection.

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10Ying Y. Luo & Benoit Guénard

Paratopula oculata Smith, 1857 (Borneo, W.
Malaysia, Singapore) – known from male andfemale only
Paratopula sumatrensis Forel 1913 (Philippines,
Sumatra) - known from female only
Paratopula intermedia Sheela & Narendran,1998 (India)
Paratopula zhengi Xu & Xu, 2011 (Xizang, China)
Paratopula bauhinia sp. nov. (Hong Kong)
Updated key to global Paratopula species
The key to global Paratopula species is modified
and updated based on the keys and species
descriptions provided in Bolton (1988), Sheela &Narendran (2008) and Xu & Xu (2011).
1a) Dorsal surfaces of middle and hind tibiae
with short stout erect to suberect hairs and shortdecumbent to appressed pubescence (see Figure 2
in Bolton 1988) (Borneo: Brunei & E. Malaysia,
Philippines, Thailand) ............... P. macta Bolton3b) In dorsal view, pronotal humeri not angular inappearance. Median portion of the anterior margin of the pronotum round. (Figure 8b) ............ 44a) In dorsal view, postpetiole round or squarish
in shape (Figure 9a). Propodeal spines straight - ifcurved they are slightly curved downwards. .....54b) In dorsal view, postpetiole broader than longor longer than broad, not round or squarish (Figure 9b). Propodeal spines straight- if curved they
are slightly curved upward . .............................. 65a) In dorsal view, postpetiole more nearly globular (see Figure 4 in Bolton 1988). In profile view,propodeal spines straight. Postpetiole in profile
with tergite relatively long low and shallowly
convex. Sternite of postpetiole elongate and narrow in profile (Indonesia: Sulawesi).....................
................................................ P. catocha Bolton

1b) Dorsal surfaces of middle and hind tibiae
lacking standing hairs, at most with short decumbent to appressed pubescence............................ 25b) In dorsal view, postpetiole squarish (see Figure 5 in Bolton 1988). In profile view, propodeal
spines straight to feebly down curved. Postpetiole
in profile view with tergite relatively short andmore strongly convex. Sternite of postpetiole
short and deep in profile. (Bangladesh, China, India, Myanmar, Pakistan, Sri Lanka, Taiwan)........
............................................ P. ceylonica (Emery)2a) In profile view, propodeal spines long stout,
downcurved along their length. Propodeal lobes
sharply hooked upwards apically, their apices
directed vertically (see Figure 1 in Bolton 1988)(Borneo: Brunei) .................... P. ankistra Bolton6a) In dorsal view, postpetiole longer than broad(see Figure 4 in Sheela & Narendran 2011). In
full face view frontal carinae indistinct behindfrontal lobes. Propodeal lobes angulated apically.
(India) .......... P. intermedia Sheela & Narendran2b) In profile view, propodeal spines either
straight or weakly curved. Propodeal lobes not
sharply hooked, if hooked, only slightly so........36b) In dorsal view, postpetiole broader than long
(Figure 5), trapezoidal in shape. In full face view
frontal carinae fine and continuous, about as longas scapes. Propodeal lobes truncated apically ...73a) In dorsal view, pronotal humeri angulate. Median portion of the anterior margin of the pronotum angular (Figure 8a) (Indonesia, E. Malaysia)................................................. P. demeta Bolton

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Xu & Xu 2011). In dorsal view, propodeal spines
tapering to a point (Figure 7a). Mandibles with
9 teeth. Dorsum of body with short, blunt hairs(China).................................. P. zhengi Xu & Xu

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Fig. 7. A dorsal view comparison of the propodeal spines in A) P. zhengi (from pers. comm., holotype, photographedby Zheng Hui Xu). Propodeal spines taper B) P. bauhinia (holotype). Propodeal spines rounded.

Fig. 8. A dorsal view comparison of the anterior margin the pronotum in A) P. demeta (from AntWeb 2016,
CASENT0901742, photographed by Will Ericson), pronotal humeri and the median portion of anterior marginof the pronotum angular. B) P. catocha (from AntWeb 2016 CASENT0901743, photographed by Ryan Perry).
Pronotal humeri and the median portion of anterior margin of the pronotum round.

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12Ying Y. Luo & Benoit Guénard

7b) In profile view, propodeal spines straight. In
dorsal view, propodeal spines not tapering andround at the tip (Figure 7b). Mandibles with 10
teeth. Dorsum of body with apically acute hairs.
(Hong Kong) ....................... P. bauhinia sp. nov
Description of female caste
Rotastruma stenoceps Bolton
Material examined. An individual collected in
HONG KONG, Lung Fu Shan Country Park, at N
22.279139 E 114.136755, elevation 273m, handcollected at approximately 21:00 h, 21.iv.2016(Ying Y. LUO), label “ANTWEB1009015”
deposited at SBSHKU.
Female description
Material examined. HL 0.72 mm; HW 0.85 mm;
MaL 0.41 mm; SL 0.59 mm; EL 0.25 mm; WL
1.21 mm; PNW 0.62 mm; PNH 0.48 mm; MW
0.56 mm; SPL 0.31 mm; PTL 0.61 mm; PTW
0.28 mm; PTH 0.31 mm; TL 4.33 mm; PPL 0.31mm; PPW 0.28 mm; PPH 0.30 mm; CI 85; SI 81;
MaI 56; PI 46; PPI 118
Head. In full face view, head rectangular inshape, slightly wider than long (CI 85). Posterior margin of head straight and posterior cornersof head rounded as in worker (see figure 15 in
Bolton 1991). Sides of head straight and parallel.
Eyes large, in the longest dimension with a dozen
ommatidia. Median ocellus level with the posterior margin of the compound eye. Frontal carinae
extending to the occipital margin. Mandibles triangular, masticatory region of mandibles with 6
teeth. Antenna with 12 segments and terminatedwith a 3-segmented club.
Mesosoma. In profile view, dorsum of mesonotum broadly rounded. Propodeal spiracle roundand near the anterior margin of the metapleuralgland bulla. Wing scars clearly visible. Propodeal
spines slightly downcurved, almost straight, apically acute, and marginally extending beyond the
propodeal lobes. In dorsal view, mesosoma longer than wide, with anterior margin longer thanthe posterior margin.

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Metasoma. In profile view, petiole pendunculate with an ill-defined node, postpetiole roughlysquare in shape. A small denticle is present on
the ventral side of the penducle, located near the
propodeum. In dorsal view, petiole rectangularin shape, and postpetiole trapzedoidal in shape,with anterior margin of postpetiole shorter thanthe posterior margin. No sting visible.
Sculpture. Cuticle thick, all surfaces except for
the antenna, legs, penduncle and gaster sculptured. Frons with distinct parallel lines of sculpture. In profile view, sides of mesosoma laterally
costate. In dorsal view, scutum and scutellum laterally costate, petiole and postpetiole rugose torugose-reticulate. Ventral sides of peduncle conspicuously smooth First gastral tergite smooth,with some short basigastral costulae.
Pubescence. All dorsal surfaces of head, mesosoma and metasoma with short sub-erect, apically acute hairs, gold in colour. Antenna with
abundant hair, oriented to the apex. Coxa, femur
and tibia covered in short suberect hairs, oriented
towards the tarsus. Subpostpetiolar process witha few thin erect hairs.
Colouration. Whole body a uniform goldenbrown colour, mandibles slightly darker in colouration. Gaster darker, light-brown.
Castes. For worker description refer to Bolton(1991). Male caste is unknown.
Distribution
Rotastruma stenoceps is known from Hong Kongand the following Chinese provinces: Guangdong, Hubei, Hunan and Yunnan.
Ecology
Very little is known of the ecology ofRotastruma. The specimen was found walking
on a railing adjacent to a hiking trail at approximate 21:00 h. The surrounding area of the hiking
trail is a monoculture plantation of the tree Lophostemon confertus Wilson & Waterh. Whether
or not R. stenoceps is actually nocturnal is unknown at this point because the female may have
performed a nuptial flight earlier in the day andcould have been looking for a suitable location tostart a colony.

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Descriptions of a new species and the gyne in the rarely collectedarboreal genera Paratopula and Rotastruma

13

Fig. 9. A dorsal view comparison of the postpetiole in A) P. ceylonica with globular-shaped postpetiole (from
AntWeb 2016, CASENT0908985, photographed by Zach Lieberman), B) P. bauhinia (holotype) with roughly
trapezoidal-shaped postpetiole, and anterior margin shorter than the posterior margin.

Remarks
Previously, two worker specimens of R. stenoceps were found in Hong Kong in past studies,both with features as described by Bolton (1991).
In general, the morphology of the queen
is similar to the worker, as discussed by Bolton(1991), unless otherwise stated.

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This specimen is distinct from R. recava
and is similar to R. stenoceps due to the following
features: lack of concave occipital margin, sidesof head with projecting hairs, relatively straightpropodeal spines and propodeal spiracle near themetapleural gland bulla.

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14Ying Y. Luo & Benoit GuénardDISCUSSION
Paratopula bauhinia represents the first record ofthis genus in Hong Kong and only the third recordof this genus for China (others are from Shanghai
and Xizang). All specimens were found in Lung
Fu Shan Country Park, a protected country park
located close to the highly urbanized city centreof Hong Kong Island. The holotype worker was
found foraging in shallow leaf litter on a manmade structure in a highly disturbed young secondary forest, along a hiking trail (Figure 6). Thisparticular part of the trail has abandoned construction work; trash and glass litter the ground.
The paratypes were found further up the trail,
where the trail is more developed, on a railing(Figure 6). This part of the trail is located withina monoculture plantation and has thus experienced important disturbance in the past. While P.
bauhinia has been collected from only two sites,
the level of disturbance of these sites has lead us
to conclude that this species is not a mature forest
specialist but could be a species associated withyoung or disturbed forested habitats.
Despite Paratopula’s relatively large
size (it is the largest Myrmicinae known from
Hong Kong), it is still rarely collected. Previous
Paratopula specimens had been collected either
on or near trees; which suggests an arboreal or
sub-arboreal lifestyle (Bolton 1988, Eguchi et al.
2011). Rotastruma is also thought to be arboreal,
as nests of R. recava have been collected neartrees or from dead twigs (Bolton 1991). The collection times for all the specimens in this study
were at night, approximately 2 to 3 hours aftersunset. The collection of these species at night, on
raised man-made structures, suggests they may
forage near the ground nocturnally, potentially tolimit competition with dominant species more active during daytime.
Our collection events suggest that Paratopula is crepuscular or nocturnal in behaviour.
This is also the first collection event for the genus
Rotastruma for our research team (previous specimens found in Hong Kong have been caught byother research groups), although whether or not it
is nocturnal remains unknown (we haven’t seen
any R. stenoceps workers active at night) and our
discovery of the dealate queen may just be dueto the timing of the nuptial flight for the species.

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Their presumed nocturnal ecology is supportedby the absence of Paratopula and Rotastruma
specimens from diurnal sampling despite an intensive sampling program conducted in Hong
Kong over the past year which utilizes multiple
approaches (hand collection, baiting, pitfall traps
and Winkler extractors).
Collection during diurnal hours versus
nocturnal hours can cause separate communities
to be sampled, which has been illustrated intropical and subtropical regions (Tavares etal. 2008) and in hot and arid regions (Briese &Macauley 1980; Cros et al. 1997). Similarly,
individual taxa considered as rare could also be
nocturnal in behaviour, such as the rare arboreal
myrmicine genus Peronomyrmex (Shattuck 2006)or the once elusive Nothomyrmecia macrops
Clark which evaded collection for 46 years andwas finally rediscovered when researchers did anight time survey and discovered that N. macrops
is an exclusively nocturnal scavenger (Taylor
1978). Thus, in order to have a complete species
inventory, we recommend including nocturnal
sampling to maximize the collection of potential
nocturnal specialist species, especially withintropical and subtropical regions that possess richand ecologically complex ant communities.
Proposed explanations for why someant genera are so rarely collected include small
population size, habitat specificity, samplingdifficulties and inconspicuous nature (Espadaler& Lopez-Soria 1991, Brandão et al. 2008).
However, the discovery of Paratopula andRotastruma in such a disturbed habitat suggeststhat habitat-specificity may not be an issue anddue to the relatively large size of Paratopula itcannot be considered inconspicuous. Therefore
small colony size, cryptic behaviour and theunderutilisation of arboreal collection techniques
may be the reasons for the rarity of collection
events for Paratopula. Brandão et al. (2008)highlighted that very little of the life history of
rarely collected ants is known, so it is difficult
to determine which collection method is the mosteffective to use.
The discovery of Paratopula andRotastruma in Hong Kong was not unexpected;
other species of Paratopula have been recorded in
the region, in Shanghai and Taiwan (antmaps.org).
This emphasizes the possibility of discovering

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Descriptions of a new species and the gyne in the rarely collectedarboreal genera Paratopula and Rotastruma

15

Fig. 10. Specimen of R. stenoceps Bolton examined in A) profile view. B) dorsal view. C) full face view.

new records of Paratopula and Rotastruma inother provinces in China, especially since China
is regarded as an under sampled region for ant
biodiversity (Guénard & Dunn 2012). The
description of this new species from Hong Kongraises the possibility that previous identificationsof P. ceylonica from South East China could
be erroneous and re-examination of previously
collected specimens could confirm this.
The discovery of a new species of therarely collected ant genus Paratopula in Hong
Kong is further evidence that our knowledgeof the ant community in the region is still1 - 16 - AM8 - Descriptions of a new species and the gyne.indd 15

incomplete. Collection using underutilisedarboreal techniques and nocturnal sampling could
yield additional ant species records for the region.
ACKNOWLEDGEMENTS
The authors would like to thank Dr. Zheng Hui
XU for providing us with new images of theP. zhengi holotype and allowing us to use theimages, Gordon Yong for collecting and sharing
his specimen, Laura Wong for identifying thetrees near the site where the type specimens were

09-Dec-16 3:02:57 PM

16Ying Y. Luo & Benoit Guénard

found and Lily Ng for helping in imaging thespecimens. We are also very grateful to the tworeviewers, Sandor Csősz and Georg Fischer, fortheir very valuable comments on the manuscript.
Additionally we would like to thank Roger Lee,
Toby Tsang, Briony Mamo and Brian Worthington
for their input on the manuscript. This work was
supported by the Seed Funding Programme for
Basic Research for New Staff from the Universityof Hong Kong.
REFERENCES
antmaps.org, 2016. Available from https://antmaps.
org/. Accessed on January 31st 2016
Antcat.org, 2016. Available from https://antcat.org/.
Accessed on January 31st 2016
Bolton B., 1988. A review of Paratopula Wheeler, aforgotten genus of Myrmicine ants (Hym.,
Formicidae).
Entomologist’s
Monthly
Magazine, 125 – 143.
Bolton B., 1991. New myrmicine ant genera from theOriental Region (Hymenoptera: Formicidae).
Systematic Entomology, 16, 1 – 13.
Bolton B., 2004. Identification guide to the ant generaof the world. Cambridge, Mass.: Harvard
University Press, 222 pp.
Brandão C.R., Feitosa R.M., Schmidt F.A. & Solar
R.R.A., 2008. Rediscovery of the putatively
extinct ant species Simopelta minima(Brandão) (Hymenoptera, Formicidae), witha discussion on rarity and conservation statusof ant species. Revista Brasileira de Entomologia, 52, 480–483.
Briese D.T., & Macauley B.J., 1980. Temporal
structure of an ant community in semi-arid
Australia. Australian Journal of Ecology
5(2): 121 – 134.
Cros S., Cerdá X., & Retana J., 1997. Spatial and temporal variations in the activity patterns ofMediterranean ant communities. Ecoscience
4(3): 269 – 278.
Eguchi K., Bui T. V., & Yamane S., 2011. Generic synopsis of the Formicidae of Vietnam (Insecta:
Hymenoptera), part I — Myrmicinae andPseudomyrmecinae. Zootaxa 2878: 1 – 61.
Emery, C., 1901. Ameisen gesammelt in Ceylon con
Dr. W. Horn, 1899, Dt. Ent. Z., 113 – 122.

Espadaler X., & Lopez-Soria L., 1991. Rareness ofcertain Mediterranean ant species: fact or
artifact? Ins. Soc. 38:365 – 377.
Fischer G., Azorsa F., Fisher B., 2014. The ant
genus Carebara Westwood (Hymenoptera,
Formicidae):synonymisationofPheidologeton Mayr under Carebara,
establishment and revision of the C. polita
species group. Zookeys 438: 57 – 112.
Guénard B., & Dunn R., 2012. A checklist of the antsof China. Zootaxa 3558: 1 – 77.
Janicki, J. H., Narula, N. Ziegler, M. Guénard B. &Economo. E. P. Visualizing and interactingwith large-volume biodiversity data using
client-server web mapping applications: The
design and implementation of antmaps.org.
Ecological Informatics 32: 185 – 193.
Longino, J. T., 2003. The Crematogaster (Hymenoptera, Formicidae, Myrmicinae) of Costa
Rica. Zootaxa 151: 1 – 150
Serna, F., & Mackay, W., 2010. A descriptive morphology of the ant genus Procryptocerus (Hymenoptera: Formicidae). Journal of Insect Science, 10: 111.
Shattuck S.O., 2006. A third species in the rare Australian ant genus Peronomyrmex Viehmeyer(Hymenoptera: Formicidae). Zootaxa 1194:
49 – 55.
Sheela S., & Narendran T. C., 1998. A new species of
the genus Paratopula Wheeler from India,
Geobias new Reports, 17 (1): 23 – 26.
Tavares A.A., Bispo P.C., & Zanzini, A.C., 2008.
Effect of collect time on communities of
epigaeic ants (Hymenoptera: Formicidae) inareas of Eucalyptus cloeziana and Cerrado.
Neotropical Entomology 37(2): 126 – 130.
Taylor R.W., 1978. Nothomyrmecia macrops: A Living
Fossil Ant rediscovered. Science 201: 979 –985.
Ward P. S., Brady S. G., Fisher B. L., & Schultz T. R.,
2015. The evolution of myrmicine ants: phylogeny and biogeography of a hyperdiverse
ant clade (Hymenoptera: Formicidae). Systematic Entomology, 40(1): 61 – 81.
Wheeler W. M., 1919. The ants of Borneo Bull. Mus.
comp. Zool. Harv. 63: 43 – 147.
Xu Z.H., & Xu G. L., 2011. A new species of thegenus Paratopula Wheeler (Hymenoptera,
Formicidae). Acta Zootaxonomica, 36 (3):595 – 597.

ASIAN MYRMECOLOGY
A Journal of the International Network for the Study of Asian Ants
Communicating Editor: Francisco Hita Garcia

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