ore

JHR TTS I 39-| 50 (2020) JOURNAL OF A peer-reviewed open-access journal
doi: 10.3897/jhr.77.52797 RESEARCH ARTICLE (ME Hymenoptera

http://jhr.pensoft.net The Insertional Society of ymenoptersts. RESEARCH

Potter wasps of the genus Labus (Hymenoptera,
Vespidae, Eumeninae) from Vietnam,
with description of two new species

Lien Thi Phuong Neuyen!”, James M. Carpenter?

I Lnsect Ecology Department, Institute of Ecology and Biological Resources, Vietnam Academy of Science and
Technology, 18 Hoang Quoc Viet Road, Nghia Do, Cau Giay, Hanoi, Vietnam 2. Graduate school of Science
and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, Nghia Do, Cau
Giay, Hanoi, Vietnam 3 Division of Invertebrate Zoology, American Museum of Natural History, Central Park
West at 79th Street, New York, NY 10024, USA

Corresponding author: Lien Thi Phuong Nguyen (phuonglientit@gmail.com)

Academic editor: Michael Ohl | Received 1 April 2020 | Accepted 9 June 2020 | Published 29 June 2020
http.//zo0bank.org/D4E29762-COD 5-46 BB-BC32-F197161B0556

Citation: Nguyen LTP, Carpenter JM (2020) Potter wasps of the genus Labus (Hymenoptera, Vespidae, Eumeninae)
from Vietnam, with description of two new species. Journal of Hymenoptera Research 77: 139-150. https://doi.
org/10.3897/jhr.77.52797

Abstract

Taxonomy of the potter wasps of the genus Labus from Vietnam is reviewed, with six species recorded.
Of them, one species previously identified as L. clypeatus van der Vecht, 1935 is described as new, namely
L. angulus, sp. nov. Another new species, Labus obtusus sp. nov., is also described. In addition, a key to all

species of the genus occurring in Vietnam is given.

Keywords

Labus, solitary wasps, new species, Vietnam

Introduction

The genus Labus was created by de Saussure (1867), and Bingham (1897) subsequently
designated Labus spiniger as type. Up to now, the genus contains 16 species, all distrib-
uted in the Oriental region (van der Vecht 1935; Giordani Soika 1960, 1973, 1986,
1991; Gusenleitner 1988; Girish Kumar et al. 2014; and Li and Carpenter 2018).

Copyright L.T.P. Nguyen, J.M. Carpenter. This is an open access article distributed under the terms of the Creative Commons Attribution License
(CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

140 L.T-P Nguyen & J.M. Carpenter / Journal of Hymenoptera Research 77: 139-150 (2020)

Nguyen et al. (2014) recorded the genus and two species, Labus clypeatus van der
Vecht, 1935 and Labus lofuensis Giordani Soika, 1973 from Vietnam. Careful examina-
tion of the specimens of the first taxon show that it is not Labus clypeatus but a new spe-
cies close to it, which shares the character of propodeum posteriorly on each side without
a tooth above the apical spine, but it has apical teeth of the clypeus sharper and frontal
ocellus larger. Recently, Li and Carpenter (2018) recorded two other species from Viet-
nam, namely Labus amoenus van der Vecht, 1935 and Labus pusillus van der Vecht, 1963.

In this paper, based on specimens deposited in the Institute of Ecology and Biolog-
ical Resources (IEBR), two new species of the genus Labus from Vietnam are described
and figured. A key to all species occurring in Vietnam is also presented.

Material and methods

All material including the holotype of the new species is deposited in the Institute of
Ecology and Biological Resources (IEBR), Hanoi, Vietnam. The adult morphological
and color characters were observed using pinned and dried specimens under a stereo-
scopic microscope. Measurements of body parts were made with an ocular micrometer
attached to the microscope. “Body length” indicates the length of head, mesosoma
and the first two metasomal segments combined. Terminology follows Carpenter and
Cumming (1985) and Yamane (1990). Photographic images were made with a Nikon
SMZ 800N Digital Stereo Microscope, using Helicon Focus 7 software; the plates
were edited with Photoshop CS6.

In the descriptions of adult morphology, the following abbreviations are used: The
abbreviations F, S and T refer to numbered flagellomeres, metasomal sterna and meta-
somal terga, respectively; IED-c and ISD-c refers to collectors of the Insect Ecology
Department and Insect Systematic Department, IEBR.

Taxonomic accounts

Genus Labus de Saussure, 1867

Labus de Saussure, 1867, Reise Novara, Zool. 2 (1), Hym: 3, genus.

Type species. Labus spiniger de Saussure, 1867, by subsequent designation of Bing-
ham 1897: 348.

Labus angulus Nguyen & Carpenter, sp. nov.
http://zoobank.org/88E70FB5-4FAE-42E6-8962-D224179CD050
Figs 1-7

Labus clypeatus van der Vecht, 1935: Nguyen et al. 2014: 11, misidentification.

Genus Labus from Vietnam 141

Material examined. Holotype, female, Vietnam: Dien Bien, 21°56'16.7"N,
102°52'58"E, alt. 500 m, 22 Jul. 2009, Nguyen TPL, Pham HP & Kojima J leg.,
deposited in IEBR.

Dianosis. ‘This species can be distinguished from all other congeners by the fol-
lowing combination of characters: Propodeum with posterior excavation not margined
above; metasomal segment I long and slender, swollen part slightly longer than half the
total length of the petiole; TI in dorsal view more than 9 times as long as wide at base;
TI with thick lamella, about 1.16 times as long as wide in dorsal view; female frontal
fovea much larger than anterior ocellus, oval.

Description. Female (Fig. 7). Holotype: Body length 7.2 mm; fore wing
length 6.2 mm.

Head in frontal view subcircular, about 1.1 times as wide as high (Fig. 1). Head
with frontal fovea much larger than anterior ocellus, oval, with distinct border (Fig. 2).
Gena almost as wide as eye; occipital carina complete, present along entire length of
the gena. Inner eye margins strongly convergent ventrally, in frontal view nearly 1.45
times further apart from each other at vertex than at clypeus (Fig. 1). Clypeus in lateral
view prominently convex at basal half, then slightly depressed and bent backward to
apical margin; in frontal view about 1.18 times as wide as high (Fig. 1), with basal
margin slightly convex medially and distinctly separated from antennal sockets; apical
margin emarginated medially, forming a sharp tooth on each side (Fig. 1); width of the
emargination about 1/4 width of clypeus between inner eye margin. Mandible with
four prominent teeth. Antennal scape about 4.4 times as long as its maximum width,
curved; FI about 1.26 times longer than wide, FII-II longer than wide, FIV—IX wider
than long, terminal flagellomere bullet-shaped, as long as its basal width.

Mesosoma longer than wide in dorsal view (Fig. 3). Pronotal carina raised, prono-
tal corner strongly produced to form long and sharp projection (Fig. 2). Mesoscutum
weakly convex, 1.2 times as long as wide between tegulae. Scutellum weakly convex,
in lateral view at the same level as mesoscutum. Metanotum with a short, tooth-like,
sharp tubercle in the middle. Propodeum (Fig. 4) excavated in the middle apically,
with posterior excavation not margined above, with a distinct median longitudinal
furrow, rounded between posterior and lateral surfaces.

Metasomal segment I much narrower than segment II, swollen part slightly longer
than half of the length of the petiole (0.56 times as long as the total length of the peti-
ole) (Fig. 5). TI in dorsal view about 9.35 times as long as wide at base, and 3.45 times
as long as wide at apex (Fig. 5); TH with thick lamella, about 1.16 times as long as wide
in dorsal view; SII in lateral view almost straight from base to one-third, and slightly
convex then straight to apical margin (Fig. 6).

Body covered with short, silver hairs except lower part of propodeum with dense
long silver hairs.

Clypeus with dense, coarse punctures in the middle area, punctures sparser and
smaller at sides, each puncture bearing a silver bristle. Frons densely covered with very
coarse punctures, border between punctures with minute punctures and raised to form
reticulations. Vertex and gena with punctures similar to those on frons. Pronotum
with punctures coarser than punctures on vertex and gena. Mesoscutum densely and

142 L.T-P Nguyen & J.M. Carpenter / Journal of Hymenoptera Research 77: 139-150 (2020)

i ( y
Wi yd gee
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h
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NG

WW |

ia
ee

Vy. ‘i

Figures |-7. Labus angulus sp.nov., holotype, female | head, frontal view 2 head, dorsal-frontal view
3 mesosoma, dorsal view 4 propodeum, posterior view 5 TI, dorsal view 6 matasomal segments, lateral

view 7 habitus. Scale bars: 0.5 mm.

coarsely covered with punctures similar to those on pronotum, punctures on scutellum
dense, coarse and equal than those on mesoscutum, punctures on metanotum smaller.
Mesepisternum with punctures similar to those on pronotum posterodorsally, minute

Genus Labus from Vietnam 143

punctures anteroventrally; border between posterodorsal and anteroventral parts in-
distinct. Dorsal metapleuron with long striae, ventral metapleuron with short striae
at inner side, and with sparse shallow punctures. Propodeum with sparse and strong
punctures on dorsal and posterior parts, punctures on lateral parts sparser and shal-
lower. TI densely covered with strongly rugose punctures on basal half, with sparse and
strong punctures on apical half, TH with sparse and small punctures.

Colour. Body black; following parts orange-yellow: an arcuate transverse band at
basal margin of clypeus, large spot on each side of pronotum, two transverse spots on
scutellum, spot on apical spine, outer side of tegulae and parategulae, apical band of TI
and II. Spot near apical margin of metasomal segment I brown. Legs black; following
parts orange-yellow: spot at apical margin of fore and middle femur, fore tibia entirely
and outer part of middle tibia.

Male. Unknown.

Distribution. North Vietnam.

Remarks. ‘This species comes close to Labus clypeatus van der Vecht in having the
propodeum with posterior excavation not margined above, and pronotum with long
and sharp projection at the lateral corners, but it is different from the latter by the fe-
male head with frontal fovea much larger than anterior ocellus, oval (head with frontal
fovea small, slightly larger than anterior ocellus, round in L. clypeatus), female clypeus
with sharper teeth, and swollen part of the petiole longer than half the total length of
the petiole (swollen part shorter than half the total length of the petiole in L. clypeatus).

Etymology. The specific name refers to the very sharp and long projecting lateral
angle of the pronotum.

Labus obtusus Nguyen & Carpenter, sp. nov.
http://zoobank.org/ DC8AE56E-26EE-450E-8947-75D001ED3B39
Figs 8-14

Material examined. Holotype, male, Vietnam: Bidoup Nui Ba NP, Da Chais, Lac
Duong, Lam Dong, 12°08'403"N, 108°38'56.3"E, alt. 1428 m, 4 Jun. 2013, Nguyen
TPL leg., deposited in IEBR. Paratype: 1 male, same data as holotype.

Dianosis. ‘This species can be distinguished from all other congeners by following
combination of characters: Propodeum with posterior excavation not margined above;
metasomal segment | with swollen part longer than half the total length of the petiole;
TI in dorsal view slightly less than 9 times as long as wide at base; TII in dorsal view
almost as wide as long.

Description. Male (Fig. 14). Body length 6.9—7.1 mm (holotype 6.9 mm); fore
wing length 5.9-6.1 mm (holotype 5.9 mm).

Head in frontal view subcircular, about 1.2 times as wide as high (Fig. 8). Head
without frontal fovea. Gena slightly narrower than eye; occipital carina complete, pre-
sent along entire length of the gena. Inner eye margins strongly convergent ventrally;
in frontal view nearly 1.6 times further apart from each other at vertex than at clypeus
(Fig. 8). Clypeus in lateral view prominently convex at basal half, then straight to api-

144 L. TP Nguyen & ].M. Carpenter / Journal of Hymenoptera Research 77: 139-150 (2020)

cal margin; in frontal view nearly as wide as long (Fig. 8), with basal margin slightly
convex medially and distinctly separated from antennal sockets; apical margin emar-
ginated medially, forming a sharp tooth on each lateral side (Fig. 8); width of the
emargination less than 1/4 width of clypeus between inner eye margin. Mandible with
four prominent teeth. Antennal scape about 4.2 times as long as its maximum width,
curved; FI about 1.8 times longer than wide, FII-II longer than wide, FIV — VUI
wider than long, FXI nearly 1.2 times as long as wide, FX small, FXI thin, slightly
curved, and long, slightly more than 5 times as long as wide (Fig. 9).

Mesosoma \onger than wide in dorsal view (Fig. 10). Pronotal carina raised, pro-
notal corner slightly produced to form short and blunt projection (Fig. 10). Mesos-
cutum weakly convex, 1.1 times as long as wide between tegulae. Scutellum weakly
convex, in lateral view at the same level as mesoscutum. Metanotum with a short,
tooth-like, blunt tubercle in the middle. Propodeum (Fig. 11) excavated in the middle
apically, with posterior excavation not margined above, with a distinct median longi-
tudinal furrow except the middle part with short transverse striation, border between
posterior and lateral surfaces rounded.

Metasomal segment I much narrower than segment II, swollen part slightly longer
than half of the length of the petiole (0.55 times as long as the total length of the peti-
ole) (Fig. 12). TI in dorsal view about 8.8 times as long as wide at base, and 3.1 times
as long as wide at apex (Fig. 12); TH with thick lamella, almost as wide as long in dorsal
view; SII in lateral view almost straight to one-third from base, then slightly convex
and straight to apical margin (Fig. 13).

Body covered with short, silver hairs except clypeus, mandible and lower part of
propodeum with dense long silver hairs.

Clypeus with sparse and shallow punctures in the middle area, almost smooth at
sides. Frons densely covered with very coarse punctures, border between punctures
not raised. Vertex and gena with punctures similar to those on frons. Pronotum
with punctures coarser than punctures on vertex and gena, spaces between punc-
tures raised to form reticulation. Mesoscutum densely and coarsely covered with
flat-bottomed punctures, punctures on scutellum dense, coarse and equal to those
on mesoscutum, punctures on metanotum smaller. Mesepisternum with punctures
similar to those on pronotum posterodorsally, minute punctures anteroventrally;
border between posterodorsal and anteroventral parts indistinct. Dorsal metapleu-
ron with some long striae, ventral metapleuron with short striae at inner side, and
with some sparse shallow punctures. Propodeum with sparse and strong punctures
on dorsal and posterior parts, punctures on lateral parts sparser and shallower. TI
densely covered with strongly rugose punctures on basal half, with sparse and strong
punctures on apical half, TI with sparse and small punctures.

Colour. Body black; following parts yellow: clypeus except black apical margin, large
spot on each side of pronotum, two transverse spots on scutellum, spot on apical spine,
outer side of tegulae and parategulae; apical band of TI, II and SII. Legs black; following
parts yellow: spot at apical margin of middle femur and hind tibia, middle tibia entirely.

Female. Unknown.

Distribution. South Vietnam.

Genus Labus from Vietnam 145

13

Figures 8-14. Labus obtusus sp. nov., holotype male 8 head, frontal view 9 right antenna 10 meso-

soma, dorsal view I | propodeum, posterior view 12 TI, dorsal view 13 metasomal segments, lateral view

14 habitus. Scale bars: 0.5 mm.

Remarks. ‘This species comes close to Labus angulus sp. nov. in having the swollen
part of metasomal segment I longer than half of the total length of the petiole, and
propodeum with posterior excavation not margined above, but it is different from the
latter in having the pronotum with short and blunt projections at lateral corners (pro-
notum with long and sharp projections at lateral corners in L. angulus).

146 L. TP Nguyen & J.M. Carpenter / Journal of Hymenoptera Research 77: 139-150 (2020)

Etymology. The specific name refers to the obtuse lateral projections at the corners
of the pronotum.

Labus amoenus van der Vecht, 1935
Figs 15, 16

Labus amoenus van der Vecht, 1935, Treubia 15: 159, 161 (key), 162, fig. la—f, male,
female — “West-Java: ... Buitenzorg” (holotype male Leiden).

Notes. This species has been recorded from Vietnam (Ha Giang province in the north-
ern part of the country) by Li and Carpenter (2018). In our study, the species has been
newly recorded from a central province, Quang Nam.

Material examined. ViETNAM: Quang Nam: | male, Phuoc My, Phuoc son, 450—
500m, 26 May 2006; 1 male, Phuoc Son, Phuoc Hiep, 300m, 30 Jul. 2004, ISD-c.
INDONESIA: West Java: 1 female, Buitenzorg Djasinga, 6.vi.1937, M.A. Lieftinck
leg.; 1 male, Tjibarangbang Djasinga, 15.xi.2016, E.v.d.Vecht B leg.

Distribution. India: Meghalaya; Laos; Malaysia; Singapore; Indonesia: Java, Su-
matra (including Bangka); Vietnam; China.

Labus clypeatus van der Vecht, 1935
Figs 17, 18

Labus clypeatus van der Vecht, 1935, Treubia 15: 162 (key), 166, male, female, fig. 1 1-m
— “Middle-Java: ... Semarang” (holotype male Leiden).

Material examined. VietNam: Dak Lak: 1 female, Krong Buk, Pong Giang, Buon
Ho, 12°56'56.9"N, 108°16'33.8"E, alt. 706 m, 23 Jul. 2012, Nguyen TPL leg.

Distribution. Vietnam; Indonesia: Java.

Labus lofuensis Giordani Soika, 1986
Figs 19, 20

Labus lofuensis Giordani Soika, 1973, Boll. Mus. Civ. Stor. Nat. Venezia 24: 99, male,
female — “China: Lofu Mount” (holotype male London).

Notes. This species has been recorded from Vietnam (Bac Giang province) by Nguyen
et al. (2014). In our study, the species has been newly recorded from several other prov-
inces in the northern part such as Bac Kan, Lang Son, Hanoi, Hai Phong.

Material examined. VirTNAM: Bac Kan: 2 females, Kim Hy NP, Vu Muon,
Bach Thong, 22°15'51"N, 105°58'42"E, 5.viii.2012, Kojima J, Nugroho H &

Genus Labus from Vietnam 147

Figures 15-20. 15, 16 Zabus amoenus: \5 female head, frontal view 16 male head, frontal view
17, 18 Labus clypeatus, female: 17 head, frontal view 18 habitus 19, 20 Labus lofuensis: 19 female head,

frontal view 20 male head, frontal view. Scale bar: 0.5 mm.

148 L. TP Nguyen & ].M. Carpenter / Journal of Hymenoptera Research 77: 139-150 (2020)

IED-c; Lang Son: 3 females, Na Sen, Hoang Dong, 31.x.2014, 21°51'42"N,
106°43'54"E, Nguyen DD, Nguyen LTP & Nguyen PM; 8 males, Na Sen, Hoang
Dong, 31.x.2014, 21°51'42"N, 106°43'54"E, Nguyen DD, Nguyen TPL & Neguy-
en PM; Ha Noi: 1 male, Van Hoa, Ba Vi, Ba Vi NP, 3.vi.2001, Nguyen TPL; Bac
Giang: 2 females, Khe Dan, Tuan Dao, Son Dong, 4.vii.2010, Tran DD; 2 male,
Khe Dan, Tuan Dao, Son Dong, 4.vii.2010, Tran DD; 1 male, Yen Tu NR, Son
Dong, 150 m, 2.viii.2010, Pham HP; 1 male, Thanh Son, Son Dong, 7.vii.2010,
Tran DD; Hai Phong: 1 female, Cat Ba NP, 11.vi.2006; 1 female, Xuan Dam, Cat
Ba, 27.iv.2013, Nguyen DD.
Distribution. China: Guangdong, Macau, Hainan; Vietnam.

Labus pusillus van der Vecht, 1963

Labus pusillus van der Vecht, 1963, Zool. Verh., Leiden 60: 6, fig. 1b, c, female, male
— “Deiyannewela, Kandy, Ceylon” (holotype female Basel).

Notes. This species has been recorded from Vietnam (Nghe An province) by Li and
Carpenter (2018).

Material examined. No specimen is available for our study.

Distribution. Sri Lanka; India: Andhra Pradesh, Assam, Goa, Himachal Pradesh,
Karnataka, Kerala, Maharashtra, Meghalaya, Mizoram, Pondicherry, Sikkim, Tamil
Nadu, Uttarakhand, West Bengal; Nepal; Bhutan; Vietnam; China.

Key to species of Labus de Saussure, 1867 from Vietnam

The characters used are applicable to both sexes unless the sex is specified. The char-
acters are taken from the specimens of two new described species in this paper, L.
clypeatus (female) and L. amoenus (male) from Vietnam, L. amoenus (female) from

Indonesia, and from the description of L. pusillus following van der Vecht (1963).

1 Propodeum with posterior excavation not margined above ........ cesses 2
Propodeum with posterior excavation margined above... .eeeeeeeeeeseeeeeeee 2
2, TI with the total length much more than 9 times as long as wide at base,
pronotum with long and sharp projection at the lateral corners ..............0... 3
- TI with the total length less than 9 times as long as wide at base, pronotum
with shorter and blunter projection at the lateral corners... eeeeeeeeeees A
3 Metasoma segment I with swollen part less than half of the total length of the

petiole, head with frontal fovea slightly larger than anterior ocellus, round,
DOPE rao t CIS CINEES ce. Fe wait eestanterete eens nese L. clypeatus van der Vech
Metasoma segment I with swollen part slightly more than half of the total
length of the petiole, head with frontal fovea much larger than anterior ocel-
Leis Oval GE CORCISTHNCE ua Bes bctonstunt pues ibeonetcat Heda iaaeeb ete L. angulus sp. nov.

Genus Labus from Vietnam 149

4 TI in dorsal view less than 7 times as long as wide at base; basal half cover
with slightly rugose punctures. Male clypeus with slightly convex basal mar-
PINs APICAl TSCUINGAALP cveuccnreveconvesncont toacertorrevsevers L. pusillus van der Vecht
= TI in dorsal view more than 8 times as long as wide at base; basal half cover
with strongly rugose punctures. Male clypeus with strong convex basal mar-
gins -dpicalteeth bl tunter sean. .cotsese orbs csotgestonetcegt et done ee L. obtusus sp. nov.
5 Female head with frontal fovea deep, distinctly defined, and round; punc-
tures on apical half of petiole and TII stronger and denser; the yellow part of
scutellum not divergent, transverse and without roundly projecting posterior
angles (or projection very weak)... eee L. lofuensis Giordani Soika
= Female head with frontal fovea shallower, not distinctly defined, and oval;
punctures on apical half of petiole and TII weaker and sparser; the yellow part
of scutellum with slightly divergent sides and roundly prominent projecting
POSLEPLOT ANIC IES 4h. x. eoen sata bushels diets sasoneabtedtioabe L. amoenus van der Vecht

Acknowledgements

We thank Hari Nugroho for sending the Labus specimens from Indonesia. ‘The present
study was supported by a grant from the Vietnam National Foundation for Science

and Technology Development (NAFOSTED: no. 106.05-2018.303).

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