ASIAN MYRMECOLOGY Volume 10, e010001, 2018ISSN 1985-1944 | eISSN: 2462-2362 © Chi-Man Leong, Seiki Yamane
and Benoit Guénard

DOI: 10.20362/am.010001

Lost in the city: discovery of the rare ant genus Leptanilla(Hymenoptera: Formicidae) in Macau with description of
Leptanilla macauensis sp. nov.
Chi-Man Leong1, Seiki Yamane2 and Benoit Guénard3*
Department of Entomology, National Taiwan University,
No. 1, Roosevelt Road, Section 4, Taipei, 106 Taiwan
2
Kagoshima University Museum, Kôrimoto 1-21-30,
Kagoshima-shi, 890-0065 Japan3
School of Biological Sciences, University of Hong Kong, Kadoorie
Biological Sciences Building, Pok Fu Lam Road, Hong Kong SAR, China
1

Corresponding author: bguenard@hku.hk*

ABSTRACT. The rare ant genus Leptanilla was discovered in Macau SAR,
China for the first time, which represents the second record for this genus
in southeastern China. Through the detailed examination, the new species
Leptanilla macauensis sp. nov. described here has unique character conditions
particularly in the structure of the clypeus and subpetiolar process. Moreover,the discovery of L. macauensis sp. nov. within an island of vegetation
surrounded by a dense urbanized matrix illustrates future possibilities forthe discovery of new species in South East Asia, including within heavily
disturbed environments.
Keywords: Leptanillinae, Leptanilla, Macao, new species, urbanized habitat
INTRODUCTION
The ant genus Leptanilla Emery, 1870 consistsof 46 species globally (AntCat 2017). This genus
belongs to the subfamily Leptanillinae, whichis considered as one of the early ant lineages(Brady et al. 2006), and Leptanilla is characterized among Leptanillinae by the presence of a
distinct postpetiole, subtriangular mandible with
3 to 5 teeth, exposed antennal insertion close to
the anterior margin of clypeus, pronotum and mesonotum completely separated by promesonotal
suture, and slender body shape (Bolton 1990),
with peculiar subterranean life history (Brady
et al. 2006). Masuko (1989, 1990) documented
the feeding habits of L. japonica Baroni Urbani,
1977, with workers being specialized predatorsof geophilomorph centipedes, while the queen
feeds on hemolymph produced by larvae from

specialized duct organs. The cryptobiotic andsubterranean habits of Leptanilla ants limits thecollection of the worker and queen castes (Baroni Urbani 1977; Bolton 1990; Wong & Guénard
2016), with the use of specific subterranean sampling methods increasing the capture of Leptanillinae workers (Man et al. 2017, Wong & Guénard
2017).
In the Oriental region, 17 species of
Leptanilla have been recorded so far (antmaps.
org 2017; Guénard et al. 2017). However, both
the diversity and distribution of Leptanilla species are probably underestimated as shown by
their patchy distribution in Asia and the recent records of new species or records collected throughthe use of leaf litter or subterranean sampling
methods (Wong & Guénard 2016). For instance,
Wong and Guénard (2016) used subterranean
traps and Winkler extractors, and discovered a

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Chi-Man Leong, Seiki Yamane & Benoit Guénard

new species, L. hypodracos, in Singapore and recorded a species L. cf. japonica from Hong Kong.
However, until recently, these collecting methods
have been seldom used in China (Liu et al. 2015;
Man et al. 2017). Leptanilla species are generallycollected from forested habitats, including within
secondary forests (Masuko 1989, Wong & Guénard 2016, Man et al. 2017).
In the present study, a new species,
Leptanilla macauensis sp. nov., is describedbased on workers recently collected using a Winkler extractor in a highly urbanized site on a small
hill of Macau SAR, southeastern China. It canbe distinguished from other Asian species by a
combination of character conditions, particularly
found in the structure of the clypeus and subpetiolar process. In addition, the updated key to the
Oriental and Sino-Japanese species of Leptanillais provided.
MATERIALS & METHODSThe holotype (worker) and three paratype workers were point-mounted, and used for morphological examination; one paratype worker ispreserved in a vial within 95% ethanol. Typespecimens are deposited in the following institutions/collections.
CAS

California Academy of Sciences, San
Francisco, CA, USA
SBSHKU Insect Biodiversity and Biogeography
Laboratory, School of Biological Sciences, the University of Hong Kong,
Hong Kong SAR
SKYC
Sk. Yamane collection, Kagoshima
Prefecture, Japan
Terminology
The morphological terminology follows Baroni
Urbani (1977) and Bolton (1990).
Measurements and indices definitions
are described below and presented in Figure 1.
HL

Head length. Maximum length of head in
full-face view, measured from mid-point ofanterior clypeal margin to mid-point of line
across the posteriormost points of head.

HW

Head width. Maximum width of head in
full-face view.

MaL Mandible length. Maximum length ofmandible in full-face view, measured fromposterolateral base to apex of mandible.
SL

Scape length. Maximum length of scapeexcluding basal neck and condyle.

PnW Pronotal width. Maximum width of pronotum in dorsal view.
PnH

Pronotal length. Maximum length of pronotum in dorsal view, measured between
anterior and posterior margins.

MW Mesonotal width. Maximum width of mesonotum in dorsal view.
PtL

Petiole length. Maximum length of petiole
in dorsal view.

PtW

Petiole width. Maximum width of petiole
in dorsal view.

PtH

Petiole height. Maximum height of petiole in lateral view, measured from dorsalmost point of node to ventralmost pointof sternite.

PpL

Postpetiole length. Maximum length of
postpetiole in dorsal view (excluding helcium).

PpW Postpetiole width. Maximum width of
postpetiole in dorsal view.
PpH

Postpetiole height. Maximum height of
postpetiole in lateral view, measured fromdorsalmost point of node to ventralmost
point of sternite.

WL

Weber’s Length of mesosoma, measured
from the point between cervical shield andpronotum to posteroventral point of propodeum.

Discovery of the rare ant genus Leptanilla

3

Fig. 1. Measurements of the Leptanilla worker caste: A: body, lateral view; B: body, dorsal view; C: head, fullface view. Abbreviations are shown in the section of Materials and Methods.

Fig. 2. Holotype worker-LCM00039 L. macauensis sp. nov., head in full-face view.

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TL

Chi-Man Leong, Seiki Yamane & Benoit Guénard

Total length. Total length = HL + ML (mesosoma length, measured from anteriormost point of pronotum to posteriormost
point of propodeum) + PtL + PpL + GL
(gastral length, excluding sting).

CI

Cephalic Index. (HW ÷ HL) × 100

SI

Scape Index. (SL ÷ HW) × 100

MaI

Mandibular Index. (MaL ÷ HW) × 100

PI

Petiolar Index. (PtW ÷ PtL) × 100

PHI

Petiolar Height Index. (PtW ÷ PtH) × 100

PPI

Postpetiolar Index. (PpW ÷ PpL) × 100

PPHI Postpetiolar Height Index. (PpW ÷ PpH) × 100
All specimens were examined understereomicroscopes (Leica M205C; Leica Z16
APO, Wetzlar, Germany; Nikon SMZ18, Japan),and photographed using digital cameras (Leica
DFC450 or DFC490, Wetzlar, Germany), with a
total of 25 to 30 images per view taken, then postprocessed by the software Helicon Focus 6.3.5(Helicon Soft., Kharkiv, Ukraine) or Leica Application Suite V4 software. SEM images weretaken by a scanning electron microscope (JSEM5600, JEOL); specimens were sputter-coated using a sputter coater (SPI Module). Finally, thepictures were typeset by Photoshop CC (Adobe®
Photoshop® software). The measurements ofspecimens were firstly accurate to 0.001 mm andsecondarily rounded to the nearest 0.01 mm by thesoftware ImageJ (Schindelin et al. 2012). In addition to comparing other Leptanilla species from
Oceania, Oriental and Sino-Japanese regions,images of types of Leptanilla species (L. butteli
CASENT0901484, L. escheri CASENT0907607,
L. japonica CASENT0902775, L. lamellata ANTWEB1008004, L. oceanica CASENT0911452,
L. taiwanensis CASENT0902777, L. tanakai
CASENT0911453, L. thai CASENT0911455,
L. havilandi CASENT0907032, L. yunnanensis
CASENT0235340) were examined when available in Antweb.org (2017); the specimens (L.
clypeata, L. hypodracos MW150615-1.2); andthe original descriptions.

TAXONOMY
Leptanilla macauensis Leong, Yamane & Guénard, sp. nov.
http://zoobank.org/DCE005C4-CF69-4A3FA94F-DB0F47C17FD6(Figs. 2, 5, and 7: holotype (worker), Figs. 3, 4, 6,
8, and 9: paratype workers)
Leptanilla sp. mo01: Leong et al. 2017: 12
Holotype. Worker, Macau SAR, Ilha VerdeHill, 22.21191˚N, 113.53778˚E, 21 m elevation,
25.I.2017, Winkler extractor set up for sevendays, leg. C. M. Leong, specimen ID and depository: “CML20170125a, LCM00039” in SBSHKU.
Paratypes. Four workers from the same
Winkler extractor sample as the holotype,“CML20170125a, LCM00003” in SKYC,“CML20170125a, LCM00001” in CAS,
“CML20170125a, LCM00002” in SBSHKU,“CML20170125a, LCM00040 in SBSHKU (keptin 95% alcohol; head separated with the mesosoma and bited on a minor of Pheidole megacephala).
Measurements (mm) and indices. Holotype(worker): HL: 0.25; HW: 0.18; MaL: 0.09; SL:
0.10; PnW: 0.13; PnH: 0.12; MW: 0.10; PtL:
0.09; PtW: 0.07; PtH: 0.09; PpL: 0.07; PpW:
0.08; PpH: 0.10; WL: 0.32; TL: 1.12; CI: 72, SI:
49, MaI: 55, PI: 84, PHI: 78, PPI: 118, PPHI: 80.
Paratype workers (n=3): HL: 0.25–0.26; HW:
0.18–0.19; MaL: 0.10–0.11; SL: 0.09–0.11; PnW:
0.12–0.13; PnH: 0.09–0.11; MW: 0.10–0.11; PtL:
0.08; PtW: 0.07; PtH: 0.09; PpL: 0.07; PpW:
0.08; PpH: 0.10; WL: 0.31–0.33; TL: 1.12–1.14;
CI: 72–74, SI: 49–56, MaI: 51–56, PI: 84–88,
PHI: 78–81, PPI: 118–124, PPHI: 80–86.
Description of worker. Head. In full-face view(Fig. 2), head rectangular, distinctly longer thanbroad (CI: 72–74), with moderately concave posterior margin and weakly convex lateral margin,
with posterolateral corners rounded. Clypeus(Fig. 3) not posteriorly separating from frons; anteromedian portion of clypeus forming a roundly raised disc of which anteromedian margin isDiscovery of the rare ant genus Leptanilla

Fig. 3. Paratype worker-LCM00002 L. macauensis sp. nov., clypeus (the arrows indicate the clypeal lobes).

Fig. 4. Paratype worker-LCM00001 L. macauensis sp. nov., clypeus (the arrows indicate the extensions).

5

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Chi-Man Leong, Seiki Yamane & Benoit Guénard

armed with a pair of triangular extensions (Fig.
4); the disc separated from antennal socket bydeep furrow: three short anterior lobes extended
from clypeus, clearly differentiated from raised
disc; the median lobe separated by distinct gap
from lateral lobes (Fig. 3). Eyes absent. Masticatory margin of mandible (Fig. 4) with a totalof three distinct teeth; basal tooth strong andupward-directed; preapical tooth almost as large
as basal tooth; apical tooth very strong. Antenna
12-segmented; scape rather short and widest at its
middle portion, not reaching mid-length of head;pedicel cone-shaped, distinctly narrowed toward
base; each of 3rd to 11th segments very short, distinctly broader than long; 12th segment almost
twice as long as broad, 2.7 times as long as eachof 10th and 11th segments.
Mesosoma. Mesosoma with promesonotal suture deeply incised, without metanotal groove,with dorsum in lateral view flat but interrupted
by promesonotal suture. Pronotal neck in dorsal
view gradually narrowed anteriad, with weakly
convex anterior margin; pronotal disc (pronotum
excluding the neck) in dorsal view almost as longas broad, with weakly convex anterior margin,
roundly convex lateral margin, and weakly convex posterior margin; posterolateral corner of thedisc produced posteriad (Fig. 6A). Propleuron inlateral view (Fig. 7) triangular in shape. Mesonotum in dorsal view with round anterolateral cornerand straight lateral margin. Metapleuron clearly
separated from mesopleuron by distinctly incised
suture, with a deep pit at upper most point, but
not demarcated from lateral face of propodeum;
metapleural gland orifice large and oval (Fig. 8).
Metasoma. Petiolar node (abdominal segment II)
in dorsal view (Fig. 5) rectangular, clearly longer than broad (PI: 84–88), with weakly concave
straight anterior, moderately convex posterior,and convex lateral margins; petiolar node in lateral view (Fig. 7) with steep and slightly convex
anterior and posterior margins, and with roundly
convex dorsal margin; petiolar spiracle locatedclose to anterior margin of tergite; ventral marginof sternite convex, with shallow median indentation; subpetiolar process poorly developed as asmall and hook-like spine (Fig. 9). Postpetiolar
node (abdominal segment III) in dorsal view sub-circular, broader than long (PPI: 118–124), withalmost straight anterior margin and weakly convex posterior margin, in lateral view sub-round
dorsally; sternite large, bulging ventrally, notclearly differentiated from tergite, but postpetiole
with anterior incision; spiracle located behind theincision. Abdominal segment IV (gastral segmentI) in dorsal view slightly longer than broad, narrowed anteriad; anterior margin widely concave
and notched; lateral margin convex.
Sculpture. Body extensively smooth and shinning; punctation generally sparse and superficial.
Head superficially punctate, with smooth interspace; disc of clypeus smooth; mandible deeply
punctate on outer surface; antenna densely punctate, with interspaces smooth. Pronotal neck with
about 10 transverse striae (Fig. 6A); anteromost
section of mesonotum bearing some strong andtransverse striae; upper half of mesopleuron,
metapleuron and lateral face of propodeum withsuperficial punctuation; lower half of mesopleuron reticulate-striate; area around metapleuralgland orifice nearly transversely striate; petiolar
node superficially punctate on its dorsum; lower
half of the node and pre- and poststernite of petiole reticulate-punctate; postpetiolar node superficially punctuate on dorsum; pre- and poststerniteof postpetiole transversely striate; gastral tergites
almost smooth, at most with sparse and superficial punctation.
Pilosity. Head including mandible with dense
hairs, with some portions glabrous (Fig. 6C,
condition can be variable among specimens); antenna with dense short erect and suberect hairs.
Hair condition on mesosoma heterogeneous; pronotum with dense short hairs mixed with sparser,
longer hairs; mesonotum, and dorsa of propodeum and waist with most hairs relatively longand often slanting, with reduced pilosity of shorthairs; venter of waist with sparse, relatively long
hairs. Gastral tergites with dense suberect hairs
and few short decumbent hairs; sternites withsparely distributed and long suberect hairs. Foreleg with a few decumbent hairs on outer surfaceof femur, and scattered hairs on tibia; basitarsus
with about 10 thick and suberect hairs on ventral
surface (Fig. 6D). Mid- and hind legs with dense
decumbent hairs on femora (more hairs on outer

Discovery of the rare ant genus Leptanilla

7

Fig. 5. Holotype worker-LCM00039 L. macauensis sp. nov. in dorsal view.

Fig. 6. Paratype worker-LCM00001 L. macauensis sp. nov., A: mesosoma, dorsal view; B: petiole and postpetiole, dorsal view; C: head, lateral view; D: basitarsus, lateral view (the arrow indicate the basitarsus of foreleg).

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Chi-Man Leong, Seiki Yamane & Benoit Guénard

Fig. 7. Holotype worker-LCM00039 L. macauensis sp. nov. in lateral view.

Fig. 8. Paratype worker-LCM00001 L. macauensis sp. nov. mesosoma in lateral view.

face), and extremely dense hairs on tibiae.

Distribution. Macau SAR, China.

Coloration. Body yellowish brown; antennae
and legs lighter.

Diagnosis of worker. Leptanilla macauensis sp.
nov. can be easily distinguished from other species in the Oceanian, Oriental and Sino-Japaneseregions (Holt et al. 2013) by a combination of
the following characteristics: clypeus posteriorly

Entomology. The specific epithet is given after
the type locality (Macau).

Discovery of the rare ant genus Leptanilla

not demarcated from frons; clypeal margin witha distinct median lobe and two developed laterallobes; a total of 3 distinct teeth present on masticatory margin of mandible; metanotal groove
absent; subpetiolar process forming a small andhook-like spine. Moreover, basitarsus of forelegwith about 10 thick and erect hairs on the ventral

9surface, whereas basitarsus of foreleg with densely comb-like hairs in L. morimotoi, which is similar in some aspects to the new species. Furthermore, L. macauensis sp. nov. is relatively small
compared with other congeners from the Oriental
and Sino-Japanese regions based on average headwidth (Figure 10).

Fig. 9. Paratype worker-LCM00001 L. macauensis sp. nov. Petiole and postpetiole, lateral view.

Fig. 10. Average head width of twenty one Leptanilla species from the Oriental and Sino-Japanese regions; redcolor point represents L. macauensis sp. nov. and bars mean the range of head width when available (Data shownin appendix 1).

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Chi-Man Leong, Seiki Yamane & Benoit Guénard

Remark. Leptanilla macauensis sp. nov. wascollected with a Winkler extractor from the upper layer of soil consisting of fine sand, soil andleaf litter. It should be noted that within the same
sample a geophilomorph centipede and two ant
species (Pheidole megacephala, and Tapinoma
indicum) were also collected. The sampling site
was located near the stairs set on hillside in Ilha
Verde Hill (Fig. 11A), which had a small secondary forest of about 4.3 ha in area. Moreover, thehill was surrounded by highly urbanized areas,
isolated as an island, which is thought to be difficult for the permanently wingless Leptanillaqueen to colonize (see Bolton 1990). Historically,
the Ilha Verde Hill was a small island (based on
the historical map of 1912; Fig. 11B), however,
due to the expansion of reclamation area, became
connected to the Macau Peninsula, and since1986 the urbanization has constantly reduced
the size of natural areas. Although the speciesof Leptanilla are often collected from relatively
good forests (Wong & Guénard 2016; e.g. L. hypodracos), the case for L. macauensis sp. nov.
suggests that some Leptanilla species can survive
in small fragments of forest habitats surrounded
by intense urbanization. Moreover, the results
are consistent with previous studies in that thesmall forest/natural area might provide a niche
for maintaining ant diversity within an urban matrix (Menke et al. 2011; Guénard et al. 2015), andalso that peculiar collecting methods might provide an insight into how to discover cryptobiotic
ants (Wong & Guénard 2017).
So far, only two records of Leptanilla
have been found in southeastern China. Regarding the first record, Leptanilla sp. cf. japonica
from Hong Kong (CASENT0914941, Antweb.
org 2017), L. macauensis sp. nov. can be distinguished from Leptanilla sp. cf. japonica by the
combination of the following conditions; posterior margin of head concave in the former but almost straight in the latter; distinct median clypeal
lobe present in the former but absent in the latter;
propodeal dorsum glabrous in the former but with
distinct hairs in the latter; and body larger in theformer (HL: 0.25–0.26 mm, HW: 0.18–0.19 mm;n=4) than in the latter (HL: 0.19 mm, HW: 0.13mm; n=1).

Updated worker key to Leptanilla species fromthe Oriental and Sino-Japanese regions:This key is modified from the keys to the Oriental
species constructed by Bharti and Kumar (2012),
and Wong and Guénard (2016). To extend the
key to include the Sino-Japanese species as wellas the Oriental species (total 21 spp.) and prepare
the scatter chart (Figure 10), previous publications
were additionally consulted (Yasumatsu 1960;
Baroni Urbani 1977; Tang et al. 1992; Ito et al.
2001; Xu 2002; Xu & Zhang 2002; Terayama2013). In some critical cases, we use measurements and indices as a useful discriminating character, considering a large interspecific variation inbody size as suggested by Baroni Urbani (1977).
1) Masticatory margin of mandible with 2 teeth....
............................................................................... 2- Masticatory margin of mandible with 3 teeth or
more.................................................................... 32) Anterolateral lobes of clypeus present. 3rd antennal segment with a distinct basal peduncle.
Dorsal view of petiolar node with arched anterior
margin. Promesonotal suture narrow....................
................................. L. kebunraya Yamane & Ito- Anterolateral lobes of clypeus absent. 3rd antennal segment without distinct basal peduncle.
Dorsal view of petiolar node rectangular. Promesonotal suture wide....................... L. butteli Forel
3) Masticatory margin of mandible with 4 teeth...
............................................................................4- Masticatory margin of mandible with 3 teeth.....
............................................................................54) Full face view of 3rd abdominal tergum
strongly narrow in its anterior part (posterior
margin more than two times as wide as anterior
margin, and distinctly longer than its width (seeFig. 33 in Baroni-Urbani, 1977). The basal toothof masticatory margin of mandible distinct..........
......................................L. tanakai Baroni Urbani

Discovery of the rare ant genus Leptanilla

11

Fig. 11. A: Type locality of L. macauensis sp. nov. (red arrow; Ilha Verde Hill, Macau) and the right map shows
Ilha Verde Hill with the sampling site for Winkler extractor (from Google Map 2017); B: Type locality (red arrow; Ilha Verde Hill, Macau) in 1912 (from David Rumsey Map Collection 2017); the red rectangular of left map
shows the location of right map.

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Chi-Man Leong, Seiki Yamane & Benoit Guénard

- Full face view of 3rd abdominal tergum weakly
narrow in its anterior part (posterior margin almost one half times as wide as anterior margin,
and as long as its width (see Fig. 32 in BaroniUrbani, 1977). The basal tooth of masticatory
margin of mandible very small and difficult todistinguish...................L. japonica Baroni Urbani5) Metanotal groove present............................... 6- Metanotal groove absent................................... 76) In full-face view head approximately rectangular. Clypeus not protruding, with anterior marginroundly convex. In profile view dorsum of petiole
almost straight. In dorsal view postpetiolar nodemuch wider than petiolar node. Smaller species;
HW: ca. 0.180 mm................................................
............................L. hunanensis Tang, Li & Chen
- In full-face view head distinctly narrowed anteriorly. Clypeus protruding, with anterior margin concave. In profile view dorsum of petiole
roundly convex. In dorsal view postpetiolar nodeas wide as petiolar node. Larger species; HW: ca.
0.370 mm...............L. kunmingensis Xu & Zhang
7) Anterior margin of clypeus more or lessstraight or weakly to strongly convex................. 8- Anterior margin of clypeus medially incised, bilobed.................................................................. 148) Clypeus not protruding anteriorly, and withstraight or weakly convex anterior clypeal lobe
(Fig. 12A)............................................................9- Clypeus slightly or strongly protruding anteriorly, and with distinctly convex anterior clypeal
lobe (Fig. 12B, C)............................................. 129) Ventral margin of petiolar sternite in lateralview without well developed projection...............
......................................L. kubotai Baroni Urbani- Ventral margin of petiolar sternite in lateralview with well developed and convex projection..........................................................................10

10) Petiolar node distinctly wider than long
(PI ≥ 138)......................................................... 11- Petiolar node distinctly longer than wide (PI ≤ca. 81).............................L. morimotoi Yasumatsu
11) Postpetiolar node wider than long (PPI =163–171). Larger species; HW: ca. 0.235 mm......
................................................ L. yunnanensis Xu- Postpetiolar node almost as long as wide (PPI =88). Smaller species; HW: ca. 0.140 mm..............
..................................... L. okinawensis Terayama
12) Larger species, with petiole longer than 0.13
mm ........................... L. besucheti Baroni Urbani- Smaller species, with petiole shorter than
0.10 mm........................................................... 1313) Ventral margin of petiolar sternite with triangular projection. Subpetiolar process absent. PPI= 122–138; CI ≥ 82; PI = 111–125.......................
.................................. L. buddhista Baroni Urbani- Ventral margin of petiolar sternite with sub-circular projection. Subpetiolar process present as asmall and hook like spine. PPI = 80–86; CI ≤ 74;
PI = 117–124.....................L. macauensis sp. nov.
14) Petiole in dorsal view with sharp and protruding anterolateral corners, with well concave anterior margin (Fig. 13E, F)...................................15- Petiole in dorsal view with blunt and non-protruding anterolateral corners, with slightly concave to convex anterior margin (Fig. 13 A, B, C,
D)......................................................................16
15) Petiolar node almost twice as long as wide (PI= 60). Postpetiolar node almost as wide as long
(PPI = 90) (Fig. 13F) Propodeal dorsum and declivity in lateral view meeting at an angular corner. Masticatory margin of mandibles with a long
and well-defined basal tooth.................................
..........................L. hypodracos Wong & GuénardDiscovery of the rare ant genus Leptanilla

13

Fig. 12. Clypeus (worker) A: L. yunnanensis-CASENT0902777; B: holotype of L. macauensis sp. nov.; C: L.
hypodracos (from Wong & Guénard 2016) (the arrow indicates the anterior clypeal lobe).

Fig. 13. Petiole in dorsal view (worker) A: L. havilandi-CASENT0907032; B: L. taiwanensis-CASENT0902777;
C: L. oceanica-CASENT0911452; D: L. escheri-CASENT0907607; E: L. hypodracos (from Wong & Guénard
2016); F: L. clypeata (from Wong & Guénard 2016) (the arrow indicates the posterior margin of petiolar node).

Fig. 14. Clypeus (worker) A: L. taiwanensis-CASENT0902777; B: L. havilandi-CASENT0907032; C: L. escheriCASENT0907607 (the dotted line indicates the anterior clypeal margin).

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Chi-Man Leong, Seiki Yamane & Benoit Guénard

Fig. 15. Full-face view of head (worker) A: L. thai-CASENT0911455; B: L. havilandi-CASENT0907032; C: L.
oceanica-CASENT0911452 (the arrow indicates the posterior margin of head).

- Petiolar node almost as long as wide (PI = 82–
100). Postpetiolar node distinctly wider than long
(PPI = 133–137) (Fig. 13E). Propodeal dorsum
and declivity in lateral view meeting at a rather
rounded corner. Masticatory margin of mandibles
without a long and well-defined basal tooth.........
.....................................L. clypeata Yamane & Ito
16) Anterior margin of clypeal disc almost as
high as the lower level of antennal insertion (Fig.
14A), with shallowly notched anterior lobe..........
.........L. taiwanensis Ogata, Terayama & Masuko- Anterior margin of clypeal disc almost highly
exceeding the lower level of antennal insertion(Fig. 14B, C), with distinctly bilobed anterior
lobe.................................................................... 1717) Posterior margin of head deeply concave infull-face view (Fig. 15C)...................................18- Posterior margin of head almost straight in fullface view (Fig. 15A, B)..................................... 1918) Petiolar node rectangular with slightly concave anterior margin in dorsal view; anterior
distinctly shorter than posterior margin. Smaller
species; HW: ca. 0.155 mm..................................
................................... L. oceanica Baroni Urbani- Petiolar node square with straight anterior margin in dorsal view; anterior margin as long as posterior margin. Larger species; HW: ca. 0.29 mm..
............................... L. lamellata Bharti & Kumar
19) Petiole sternite in lateral view distinctly protruding, with ventral margin bluntly angulate.......
..........................................................................20- Petiole sternite in lateral view indistinctly protruding, with ventral margin almost straight.........
........................................... L. thai Baroni Urbani20) Masticatory margin of mandible with a totalof 3 teeth; basal tooth short and not well-defined.
Anterolateral corners of petiole roundly convex
in dorsal view (Fig. 13A). HW: ca. 0.245 mm......
................................................. L. havilandi Forel- Masticatory margin of mandible with a total of
4 teeth; basal tooth long and well-defined. Anterolateral corners of petiole forming a small andsharp angle in dorsal view (Fig. 13D). HW: ca.
0.280 mm..............................................................
................................................... L. escheri Kutter

Discovery of the rare ant genus Leptanilla

ACKNOWLEDGMENTS
We first thanks Dr. Shiuh-Feng Shiao (National
Taiwan University, Taiwan) and Dr. Chung-Chi
Lin (National Changhua University of Education,
Taiwan) for providing materials and supports,
and extending to Dr. Zheng-Hui Xu (Southwest Forestry College, China) and Mr. Hao Ran(Guangxi Normal University, China) who gave
us useful literatures. We would like to also thankDr. Mamoru Terayama (The University of Tokyo,
Japan), Dr. Katsuyuki Eguchi (Tokyo Metropolitan University, Japan) and an anonymous referee
for their valuable suggestions on an earlier version of the manuscript. Lastly, first author CML
extend his thanks to my friends, my high schoolclassmates (Kwong Tai Middle School, Macau
SAR) and my family for providing support andtheir assistance for survey in Macau.
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ASIAN MYRMECOLOGY
A Journal of the International Network for the Study of Asian Ants
Communicating Editor: Katsuyuki Eguchi

APPENDIX
Appendix 1. The head width of twenty one Leptanilla species from the Oriental and Sino-Japaneseregions with associated reference.
Species

Average (mm)Range (mm)Reference

L. okinawensis

0.140

0.14

Terayama 2013

L. oceanica

0.155

0.15–0.16

Baroni Urbani 1977

L. hunanensis

0.180

0.18

Tang et al. 1992

L. macauensis sp. nov.

0.185

0.18–0.19

Present study

L. japonica

0.195

0.19–0.20

Baroni Urbani 1977

L. morimotoi

0.200

0.20

Yasumatsu 1960

L. kebunraya

0.220

0.22

Ito et al. 2001

L. tanakai

0.220

0.21–0.23

Baroni Urbani 1977

L. buddhista

0.235

0.23–0.24

Baroni Urbani 1977

L. butteli

0.235

0.23–0.24

Baroni Urbani 1977

L. yunnanensis

0.235

0.23–0.24

Xu 2002

L. besucheti

0.245

0.24–0.25

Baroni Urbani 1977

L. havilandi

0.245

0.24–0.25

Baroni Urbani 1977

L. taiwanensis

0.245

0.24–0.25

Ogata et al. 1995

L. hypodracos

0.270

0.27

Wong & Guénard 2016

L. kubotai

0.270

0.26–0.28

Baroni Urbani 1977

L. thai

0.270

0.27

Baroni Urbani 1977

L. escheri

0.280

0.27–0.29

Baroni Urbani 1977;
Bharti & Kumar 2012

L. lamellata

0.290

0.28–0.30

Bharti & Kumar 2012

L. clypeata

0.310

0.31

Ito et al. 2001

L. kunmingensis

0.370

0.37

Xu & Zhang 2002