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Belgian Journal of Entomology 70: 1–29 (2018) ISSN: 2295-0214
www.srbe-kbve.be
urn:lsid:zoobank.org:pub:4069A87E-2CC7-4097-873E-0E21580EDF8E
Belgian Journal of Entomology
Two new stick insect genera from Vietnam,
Nuichua gen. nov. and Pterohirasea gen. nov. with two new species
(Phasmida: Diapheromeridae: Necrosciinae)
Joachim BRESSEEL¹ & Jérôme CONSTANT²
1,2 Royal Belgian Institute of Natural Sciences, O.D. Phylogeny and Taxonomy, Entomology, Vautier street 29,
B-1000 Brussels, Belgium
1 E-mail:joachimbresseel@gmail.com (corresponding author)
urn:lsid:zoobank.org:author:3C4EF358-9716-46F0-8575-26BE1EDE4349
2 E-mail: jerome.constant@naturalsciences.be
urn:lsid:zoobank.org:author:6E6072A1-9415-4C8D-8E60-2504444DB290
Published: Brussels, April 26, 2018
2
Citation: BRESSEEL J. & CONSTANT J., 2018 - Two new stick insect genera from Vietnam, Nuichua gen. nov. and
Pterohirasea gen. nov. with two new species (Phasmida: Diapheromeridae: Necrosciinae). Belgian Journal of
Entomology, 70: 1–29.
ISSN: 1374-5514 (Print Edition)
ISSN: 2295-0214 (Online Edition)
The Belgian Journal of Entomology is published by the Royal
Belgian Society of Entomology, a non-profit association
established on April 9, 1855.
Head office: Vautier street 29, B-1000 Brussels.
The publications of the Society are partly sponsored by the University Foundation of
Belgium.
In compliance with Article 8.6 of the ICZN, printed versions of all papers are deposited in the
following libraries:
- Royal Library of Belgium, Boulevard de l’Empereur 4, B-1000 Brussels.
- Library of the Royal Belgian Institute of Natural Sciences, Vautier street 29, B-1000
Brussels.
- American Museum of Natural History Library, Central Park West at 79th street, New York,
NY 10024-5192, USA.
- Central library of the Museum national d’Histoire naturelle, rue Geoffroy Saint-
Hilaire 38, F-75005 Paris, France.
- Library of the Muséum d’Histoire naturelle de Genève, route de Malagnou 1, CH-1208
Genève, Suisse.
- Zoological Record, Thomson Reuters, Publication Processing, 1500 Spring Garden Street,
Fourth Floor, Philadelphia PA 19130, USA.
Front cover: Left: Nuichua rabayae sp. nov., female in Nui Chua National Park, Vietnam, on 7.VIII.2014; right:
Pterohirasea nigrolineata sp. nov., male in Bach Ma National Park, Vietnam, 12.VII.2011 (photographs by
J. Constant).
Belgian Journal of Entomology, 70: 1–29 (2018)
3
Two new stick insect genera from Vietnam,
Nuichua gen. nov. and Pterohirasea gen. nov. with two new species
(Phasmida: Diapheromeridae: Necrosciinae)
Joachim BRESSEEL¹ & Jérôme CONSTANT²
1,2 Royal Belgian Institute of Natural Sciences, O.D. Phylogeny and Taxonomy, Entomology, Vautier street 29,
B-1000 Brussels, Belgium.
1 E-mail:joachimbresseel@gmail.com (corresponding author)
urn:lsid:zoobank.org:author:3C4EF358-9716-46F0-8575-26BE1EDE4349
2 E-mail: jerome.constant@naturalsciences.be
urn:lsid:zoobank.org:author:6E6072A1-9415-4C8D-8E60-2504444DB290
Abstract
Two new genera of stick insects are described from Vietnam. The new genus Nuichua gen.
nov. is described to accommodate one new species, N. rabaeyae sp. nov. from Nui Chua
National Park in southern Central Vietnam and the new genus Pterohirasea gen. nov. is
described to accommodate P. nigrolineata sp. nov. from coastal mountains of Central
Vietnam. The new taxa are described from males, females, nymphs and eggs. Comprehensive
illustrations, data on biology and captive rearing and a distribution map are provided. Male
genitalia inflation was conducted in N. rabaeyae sp. nov., based on the technique used for
caterpillars. Unusual mating behaviour of adult males with subadult females is reported in
N. rabaeyae sp. nov. The relevance of a resurrection of the tribe Neohiraseini Hennemann &
Conle, 2008 is discussed, as well as the importance of the presence of specialised sensory
areas on the prosternum and profurcasternum for classification. A hypothesis based on sexual
selection to explain the strong sexual dimorphism in size in N. rabaeyae sp. nov. is proposed.
Keywords: Phasmatodea, Necrosciini, Neohirasea, Oxyartes, vomer, sensory organs,
evolution
Introduction
The stick insect subfamily Necrosciinae Brunner von Wattenwyl, 1893 currently contains
about 700 species distributed in tropical and subtropical regions of Australasia, with one
species also present in Madagascar but probably introduced on that island (BRADLER et al.,
2014; BROCK et al., 2018; CLIQUENNOIS, 2012). The tribe Neohiraseini Hennemann & Conle,
2008 was recently synonymised under the Necrosciini Brunner von Wattenwyl, 1893 by
BRADLER et al. (2014). Twenty one genera of Necrosciinae have currently been recorded from
Vietnam, which contain 58 species (BROCK et al., 2018).
The identification of stick insect material collected in the framework of the Global Taxonomic
Initiative project “A step further in the entomodiversity of Vietnam” (2010– ) allowed us to
discover two undescribed species of Necrosciinae that could not be attributed to any existing
genus. Furthermore, the two species, although obviously rather closely related, represent two
distinct genera.
The first genus is here described as Nuichua gen. nov. to include a new species that was
collected in Nui Chua National Park (Ninh Thuan Province) along the coast of southern
Central Vietnam. The park covers about 24,500 ha and ranges from sea level to 1,039m on
Mount Nui Chua. It also protects a marine area with several beaches where different species
BRESSEEL J. & CONSTANT J. New Vietnamese stick insects: Nuichua and Pterohirasea (Phasmida: Necrosciinae)
4
of sea turtles have their nesting grounds. The higher portion (400m+) of the park is covered in
evergreen tropical rainforest, while the lower portion is used for agricultural purposes by local
tribes or has vegetation dominated by thorny trees and bushes. This latter habitat is generated
by a hot and dry microclimate and is completely different compared to most areas in Vietnam.
This isolates the rainforests on the mountain of Nui Chua N.P. from other rainforest areas.
The second genus, Pterohirasea gen. nov., is described to accommodate a new species from
moderately high altitude evergreen tropical rainforest in three mountainous or hilly areas
along the coast of Central Vietnam: Bach Ma National Park, Phong Dien VNMN station and
Ba Na-Nui Chua Nature Reserve. Older additional specimens from the same area were found
in the collections of the MNHN.
Both species were reared in captivity, allowing the documentation of nymphal stages and of
interesting mating behaviour in the genus Nuichua gen. nov.
The present paper aims to describe the new taxa from their male, female, nymphs and eggs,
and to provide corresponding comprehensive illustrations, biological data and a distribution
map.
Material and methods
The specimens of the treated taxa are nocturnal and were collected at night with the help of
light-weight and water-proof head torches: Petzl MYO RXP. The females were kept alive in a
mesh pop up cage (exo terra explorarium™) for producing eggs. First generation hatchlings
were reared to adulthood by the authors, Mrs Kristien Rabaey, Mr Rob Simoens and later
generations by Dr Bruno Kneubühler and Mr Tim Bollens. The wild caught specimens were
euthanized by etylacetate fumes, then stored in airtight plastic “zip”-bags in wood chips (used
in rodent cages) and sprinkled with etylacetate (EtOAc) to prevent rotting, mould and to keep
the specimens flexible. The bags were frozen on arrival and the specimens mounted later on.
For each picture of collection specimens, a number of photographs were taken with a Canon
700D camera equipped with a Sigma 50 mm Macro lens (adult specimens) or a Tamron
90 mm Macro lens (eggs), stacked with CombineZ software and optimized with Adobe
Photoshop CS3. Observations were done with a Leica MZ8 stereo-microscope. Measurements
were done with an electronic calliper. The distribution map was produced with SimpleMappr
(SHORTHOUSE, 2010).
The inflation of the phallus was done following the method used by lepidopterists for the
caterpillar inflation (HAMMOND, 1960) with the terminal part of the abdomen of a freshly
euthanized specimen.
The nomenclature for the morphological characters follows BRAGG (2001); the egg
morphology follows that of CLARK SELLICK (1997; 1998). The description of the colouration
is based on live specimens.
Acronyms used for the collections:
NHMW = Naturhistorisches Museum, Vienna, Austria.
RBINS = Royal Belgian Institute of Natural Sciences, Brussels, Belgium.
VNMN = Vietnam National Museum of Nature, Hanoi, Vietnam.
Abbreviations:
N.P.: National Park
HT: holotype
PT: paratype
Belgian Journal of Entomology 70: 1–29 (2018)
5
Taxonomy
Family Phasmatidae Gray, 1835
Subfamily Necrosciinae Brunner von Wattenwyl, 1893
Tribe Necrosciini Brunner von Wattenwyl, 1893
Genus Nuichua gen. nov.
urn:lsid:zoobank.org:act:7DDA14D6-B84E-4EA1-9574-B92EAF59CD42
Type species: Nuichua rabaeyae sp. nov. by present designation and monotypy.
ETYMOLOGY. The genus name is derived from the beautiful Nui Chua National Park in
southeast Vietnam. The gender is feminine.
DIAGNOSIS
Differing from all other known genera of Necrosciinae Brunner von Wattenwyl, 1893 by the
following combination of characters:
1) Relatively broad with all abdominal terga less than two times longer than wide and smooth
(Figs 1 A, 3 A).
2) Head with few dark tubercles, otherwise smooth (Fig. 5 I).
3) Thorax and abdominal terga smooth (Figs 1 A, 3 A).
4) Tegmina absent and alae reduced to scales (Fig. 5 H, J).
5) Femora short, subapically armed with few minute spines on the outer ventral carinae,
mesofemora swollen (Figs 1 B, 3 B).
6) Female praeopercular organ present (Fig. 3 F).
7) Vomer well developed and notched apically with two acute terminal hooks (Fig. 1 F).
8) Subgenital plate in females spoon shaped, tapering posteriorly, not reaching apex of
abdomen (Fig. 3 F–G).
9) Eggs slightly oval. Micropylar plate rounded, with a mediolongitudinal carina (Fig. 5 K–
N).
DESCRIPTION
MALE AND FEMALE (Figs 1, 3)
Head: longer than wide, with an irregular amount of distinct black granules dorsally and on
the genae; area between granules smooth. Dorsal surface slightly flattened with distinct
mediolongitudinal groove. Vertex rounded, posterolaterally with a shallow impression or
groove. Eyes circular and strongly projecting hemispherically. Antennae distinctly projecting
over front legs. Scapus slightly flattened dorsoventrally and oval in cross-section. Pedicellus
short, knob like and round in cross-section.
Thorax: pronotum slightly shorter than head; anterior margin strongly incurved with
anterolateral angles extended and rounded apically; posterior portion with lateral margins
parallel-sided. Mediolongitudinal groove starting anteriorly, not reaching posterior edge.
Centrally with a short transverse impression not reaching lateral margins; posterior margin
rounded. Mesonotum smooth and parallel-sided. Metanotum smooth and laterally with
anterolateral angles slightly extended and rounded apically. Pro-, meso- and metasterna
smooth.
Wings: tegmina absent; alae reduced to small but distinct whitish scale-like remnants.
Legs: femora relatively short, profemora compressed and curved basally. Carinae present,
antero- and posteroventral carinae armed with few minute saw-like teeth subapically.
BRESSEEL J. & CONSTANT J. New Vietnamese stick insects: Nuichua and Pterohirasea (Phasmida: Necrosciinae)
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Mesofemora laterally swollen; carinae and armature as in profemora. Metafemora as
mesofemora. Protibiae rectangular in cross-section; carinae with small setae. Probasitarsus
longer than all following tarsomeres combined. Meso- and metatibiae as protibiae. Meso and
metatarsi with claws small when compared to body size; tarsomeres with a small
posteromedian extension; ventrally with posterior portion smooth and strongly notched.
Abdomen: median segment shorter than metanotum, smooth and trapezoidal. All abdominal
terga less than two times longer than wide and smooth. Anal segment in females broad and
apically gently rounded; abdominal sternum VII with praeopercular organ present; subgenital
plate not reaching apex of abdomen, spoon-shaped and tapering posteriorly; posterior portion
with a definite median longitudinal carina. Males with tergum X apically notched. Outer
margin of inner portion of tergum X swollen and armed with several short, black spines.
Posterolateral angles rounded. Poculum not reaching base of vomer; apex broad and slightly
rounded, almost straight. Vomer well developed, represented as a broad triangular sclerite,
strongly notched posteriorly and with two apices. Apices blackish and tapering towards the
posterior. Other abdominal sterna smooth with a small posteromedian black marking.
EGG (Fig. 5 K–N)
Capsule oval; colouration cream with black markings; cream areas on capsule surface covered
with minute whitish granules. Polar area black. Operculum convex. Micropylar plate
positioned almost centrally on capsule, slightly displaced towards the polar area and oval.
Micropylar cup black and distinct, followed anteriorly by a definite mediolongitudinal carina,
and posteriorly by an elongated, black median line.
DISTRIBUTION. Southern Central Vietnam (Fig. 8).
Nuichua rabaeyae sp. nov.
urn:lsid:zoobank.org:act:36511ECA-1B3E-4CD1-AB6E-A102A4A368FC
Figs 1–8
ETYMOLOGY. The species is named after Mrs Kristien Rabaey in acknowledgement for
breeding the F1 generation of this species after the authors’ material (except one male) was
lost in an accidental domestic fire.
TYPE MATERIAL. VIETNAM: holotype ♂ (Fig. 1): Ninh Thuan prov., Nui Chua N. P.,
11°42’N 109°09’E, 3-9.VII.2014, night coll. Leg. J. Constant & J. Bresseel, GTI project
I.G.:32.779 (RBINS).
Paratypes [25♂♂, 27♀♀]: 18♂♂, 20♀♀: ex breeding J. Bresseel, 2015, origin: Vietnam,
Ninh Thuan prov., Nui Chua N.P., 11°42’N 109°09’E, 3-9.VII.2014, night coll. Leg. J.
Constant & J. Bresseel, GTI project, I.G.: 32.779 (14♂♂, 16♀♀: RBINS; 3♂♂, 3♀♀:
VNMN; 1♂, 1♀: NHMW); 1♂: ex breeding Bruno Kneubühler, origin: Vietnam, Ninh Thuan
prov., Nui Chua N. P., 11°42’N 109°09’E, 3-9.VII.2014, night coll. Leg. J. Constant & J.
Bresseel, GTI project, I.G.: 32.779, DNA 16-65 BK (RBINS); 1♂: idem, DNA 16-45 BK
(RBINS); 1♀: idem, DNA 16-64 BK (RBINS); 1♀: idem, DNA 16-44 BK (RBINS); 5♂♂,
5♀♀: ex breeding F. Hennemann, 2016, origin: Vietnam, Ninh Thuan prov., Nui Chua N.P.,
11°42’N 109°09’E, 3-9.VII.2014, night coll. Leg. J. Constant & J. Bresseel, GTI project
(Coll. Frank Hennemann, No’s FH 0899-1 to -10).
ADDITIONAL MATERIAL. VIETNAM: 150 eggs: ex breeding J. Bresseel, 2015, Origin:
Vietnam, Ninh Thuan prov., Nui Chua N. P., 11°42’N 109°09’E, 3-9.VII.2014, night coll.,
leg. J. Constant & J. Bresseel, GTI project, I.G.: 32.779 (100 eggs: RBINS; 50 eggs: VNMN).
Belgian Journal of Entomology 70: 1–29 (2018)
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Fig. 1. Nuichua rabaeyae sp. nov., holotype ♂. A, habitus, dorsal view. B, habitus, lateral view. C, habitus,
ventral view. D, head and thorax, dorsal view. E, terminalia, dorsal view. F, terminalia, ventral view. G, head
and thorax, lateral view. H, terminalia, lateral view.
BRESSEEL J. & CONSTANT J. New Vietnamese stick insects: Nuichua and Pterohirasea (Phasmida: Necrosciinae)
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Fig. 2. Nuichua rabaeyae sp. nov., ♂ genitalia. A, dorsal view. B, left lateral view. C, right lateral view.
D, posterior view. E, ventral view. F, anteroventral view.
Belgian Journal of Entomology 70: 1–29 (2018)
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DESCRIPTION
MALE (Figs 1–2, 5 A–B, E–G, 6 A, C, 7)
Measurements: see table 1.
Body: (Fig. 1 A–C) head, scapus and pedicellus greyish blue with black granules. Pro-, meso
and metanotum mahogany red with a mediolongitudinal greyish blue marking, marking
widening near the posterior margin of each segment. Abdominal terga as metanotum, but with
black markings posteriorly. Legs with coxae coloured as head; femora grass green, slightly
darkening distally. Other portions of legs grass green.
Head: (Fig. 1 D, G) longer than wide and mainly smooth, apart from few distinct granules
posteriorly and on genae. Dorsal surface slightly flattened with distinct mediolongitudinal
groove. Vertex rounded, posterolaterally also with a groove. Eyes circular and strongly
projecting hemispherically. Antennae distinctly projecting over front legs. Scapus slightly
flattened dorsoventrally and oval in cross-section. Pedicellus short, knob-like and round in
cross-section.
Thorax: (Fig. 1 D, G) pronotum slightly shorter than head; anterior margin strongly incurved
with anterolateral angles extended and apically rounded; posterior portion with lateral margins
parallel-sided. Median longitudinal groove starting anteriorly, not reaching posterior edge.
Centrally with a short transverse impression not reaching lateral edges. Posterior margin
rounded. Mesonotum longer than mesofemora, smooth and parallel-sided. Metanotum
smooth, longer than head. Anterolateral angles as in pronotum, but not as strongly
pronounced. Pro-, meso- and metasterna smooth.
Wings: (Figs 1 G, 5 H) tegmina absent; alae reduced, scale-like and whitish.
Legs: (Fig. 1 A–C) profemora slightly longer than mesonotum; compressed and curved
basally. Dorsal carinae present, but unarmed; all ventral carinae present. Antero- and
posteroventral carinae armed with three to four minute saw-like teeth subapically.
Mesofemora distinctly shorter than mesonotum and slightly swollen laterally; carinae and
armature as in profemora. Metafemora about as long as profemora, armature as in
mesofemora. Protibiae slightly longer than profemora, rectangular in cross-section with outer
ventral and dorsal carinae developed; carinae with small setae. Probasitarsus longer than all
following tarsomeres combined. Mesotibiae about as long as mesofemora; carinae as in
protibiae. Metatibiae slightly longer than metafemora. All carinae present, but unarmed with
medioventral carina raised and laterally flattened. Meso- and metatarsi with claws small when
compared to body size; tarsomeres with a small posteromedian extension ventrally with
posterior portion smooth and deeply notched.
Abdomen: (Fig. 1 A–C, E–F, H) median segment longer than wide, shorter than metanotum,
smooth and trapezoidal. All abdominal terga with indistinct median line, less than two times
longer than wide and smooth. Terga II–VI about the same, or slightly decreasing in length;
tergum VII distinctly shorter than VI; VII about as wide as long; VIII distinctly wider than
long; VII and VIII with posterolateral angles expanded and rounded; tergum X about as long
and wide as IX and with a mediolongitudinal line, apically notched with outer rim slightly
setose. Outer margin of inner portion of tergum X swollen and armed with several short, black
spines. Posterolateral angles rounded. Poculum slightly rounded, not reaching base of vomer;
apex broad and slightly rounded, almost straight. Cerci reaching about apex of abdomen, with
apices knob-like, slightly incurving and distinctly setose. Vomer well developed, represented
as a broad triangular sclerite, strongly notched posteriorly and with two terminal hooks;
apices blackish and tapering towards the posterior. Other abdominal sterna smooth with a
small black posteromedian marking.
BRESSEEL J. & CONSTANT J. New Vietnamese stick insects: Nuichua and Pterohirasea (Phasmida: Necrosciinae)
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Fig. 3. Nuichua rabaeyae sp. nov., paratype ♀. A, habitus, dorsal view. B, habitus, lateral view. C, habitus,
ventral view. D, head and thorax, dorsal view. E, terminalia, dorsal view. F, terminalia, ventral view.
G, terminalia, lateral view. H, head and thorax, lateral view.
Belgian Journal of Entomology 70: 1–29 (2018)
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Fig. 4. Nuichua rabaeyae sp. nov., nymphs. A–B, second instar. C–D, third instar. E–F, fourth instar.
BRESSEEL J. & CONSTANT J. New Vietnamese stick insects: Nuichua and Pterohirasea (Phasmida: Necrosciinae)
12
Genitalia: (Fig. 2) phallus entirely membranous; when inflated, strongly curved dorsally with
distal portion more strongly swollen and bearing a medioventral round opening; one
posteroventral inflated hump and one apicolateral inflated hump on right side.
FEMALE (Figs 3, 5 B, E–G, I–J, 6 B–C, 7)
Measurements: see table 1.
Body: (Figs 3 A–C, 6 B–C) coloured more or less like male, but less contrasted. Head and
mediolongitudinal dorsal marking on body with a greenish tinge.
Head: (Figs 3 D, H, 5 I) longer than wide, with an irregular amount of distinct black tubercles
dorsally and on genae; area between granules smooth. Dorsal surface slightly flattened with
distinct mediolongitudinal groove. Posteriorly of groove, a distinct black triangular marking.
Vertex rounded, posterolaterally with a shallow impression. Eyes circular and strongly
projecting hemispherically. Antennae distinctly projecting over front legs. Scapus slightly
flattened dorsoventrally and oval in cross-section. Pedicellus short, knob-like and round in
cross-section.
Thorax: (Fig. 3 D, H) pronotum slightly shorter than head; anterior margin strongly incurved
with anterolateral angles extended and apically rounded; posterior portion with lateral margins
parallel-sided. Mediolongitudinal groove starting anteriorly, not reaching posterior edge.
Centrally with a short transverse impression not reaching lateral edges; posterior margin
rounded. Mesonotum about as long as median segment and terga II–IV combined, smooth and
parallel-sided. Metanotum smooth. Pro-, meso- and metasterna smooth.
Wings: (Figs 3 H, 5 J) tegmina absent; alae small, whitish and scale-like.
Legs: (Fig. 3 A–C) profemora shorter than mesonotum, compressed and curved basally;
dorsal carinae present, but unarmed; all ventral carinae present; antero- and posteroventral
carinae armed with three minute saw-like teeth subapically. Mesofemora about 2/3 as long as
mesonotum and distinctly swollen laterally; carinae and armature as in profemora.
Metafemora about as long as profemora, with armature as in mesofemora, but with four
spines subapically on outer ventral carinae. Protibiae slightly longer than profemora,
rectangular in cross-section with all carinae developed; carinae with small setae. Probasitarsus
longer than all following tarsomeres combined. Mesotibiae about as long as mesofemora, with
carinae as in protibiae. Metatibiae slightly longer than metafemora. Meso- and metatarsi with
claws small when compared to body size; tarsomeres with a small posteromedian extension,
ventrally with posterior portion smooth and strongly notched.
Abdomen: (Fig. 3 A–C, E–G) median segment about as wide as long, shorter than metanotum,
smooth and trapezoidal. All abdominal terga smooth and less than two times longer than
wide. Terga II–V slightly increasing in length; terga VI and VII decreasing in length; tergum
VII about as wide as long; VIII slightly wider than long; IX about as long and wide as X,
rounded posteriorly. Anal segment broad and apically gently rounded. Abdominal sternum
VII with praeopercular organ represented by a carina followed by a single, dorsoventrally
flattened spine. Subgenital plate just not reaching halfway along anal segment, spoon-shaped
and tapering posteriorly; posterior portion with a definite median longitudinal carina. Other
abdominal sterna smooth with a small posteromedian black marking.
NYMPH (Figs 4, 5 C–D)
Newly hatched nymphs mostly mottled pale yellowish brown and black. Head reddish brown
with yellowish granules. Antennae black and white. Profemora coloured as head. Meso- and
metafemora with a greenish tinge in basal half, a whitish ring in middle, and distal portion
black.
Belgian Journal of Entomology 70: 1–29 (2018)
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Fig. 5. Nuichua rabaeyae sp. nov., captive reared, from Nui Chua N.P. (photographs by B. Kneubühler). A, ♂
lateral view. B, mating pair dorsal view. C–D, newly hatched nymph. C, dorsal view. D, lateral view. E, mating
pair lateral view. F. abdomen ♀ with adult ♂ mating. G, apices of abdomen mating pair. H, ♂ metanotum and
median segment; arrow indicates scale-like wings. I, ♀ head and pronotum. J, ♀ metanotum and median
segment; arrow indicates scale-like wings. K–N, eggs. K, lateral view. L, operculum. M, dorsal view. N, polar
area.
BRESSEEL J. & CONSTANT J. New Vietnamese stick insects: Nuichua and Pterohirasea (Phasmida: Necrosciinae)
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Fig. 6. Nuichua rabaeyae sp. nov. A–B, wild specimens (photographs by J. Constant). A, ♂, Nui Chua N.P.,
8.VIII.2014. B, ♀, Nui Chua N.P., 7.VIII.2014. C, adult pair, captive reared (photograph by M. Duytschaever).
Belgian Journal of Entomology 70: 1–29 (2018)
15
Fig. 7. Nuichua rabaeyae sp. nov., male mating with subadult moulting female. A, adult male showing mating
behaviour with subadult female starting her final moult. B, detail of male with subadult female. C, female in
final phase of moulting with male still attached to exuvia. D, adult female drying after final moult with male still
attached to exuvia. E, detail of male attached to exuvia. F, male moving to female after drying process. G, male
attached to adult female.
BRESSEEL J. & CONSTANT J. New Vietnamese stick insects: Nuichua and Pterohirasea (Phasmida: Necrosciinae)
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EGG (Fig. 5 K–N)
Measurements (in mm). Length: 2.7; width: 1.9; height: 2.2.
Capsule oval, colouration cream with black markings; cream areas on capsule surface covered
with minute whitish granules. Polar area black. Black marking on polar area tapering towards
and reaching micropylar plate. Operculum convex; central portion cream coloured with outer
margin black; cream coloured area covered with minute white granules except centrally.
Micropylar plate positioned almost centrally on capsule but very slightly displaced towards
polar area; oval, slightly darker than capsule; surface smooth, except for outer margin with
minute whitish granules. Micropylar cup black and distinct, followed anteriorly by a definite
mediolongitudinal carina and posteriorly by an elongated, black median line covered with
minute black granules and reaching polar area.
BIOLOGY.
The species was collected in secondary evergreen rainforest, at low altitude (400m). The
specimens were found foraging on low vegetation and bushes (Fig. 6 A–B).
The species is easy to rear in captivity and accepts a wide variety of alternative foodplants
including Hypericum spp. (Hypericaceae), Hedera helix L. (Araliaceae) and different species
of Rubus spp. (Rosaceae). Eggs are dropped to the ground and have a relatively short
incubation time (2–4 months). Nymphs can react hectically when disturbed, but older nymphs
often feign dead. Males mature 4 to 6 weeks earlier than females and are considerably smaller
in size than the latter, reaching only about half their length. As soon as they are adult, males
already occupy the larger female nymphs and stay with the same female for the rest of their
life. Subadult females moult with males still attached to the old skin (Fig. 7 A–E). Once the
moulting process is completed, the male moves from the old skin to the freshly moulted adult
female (Fig. 7 F–G). When a lone male comes close to an occupied female or even when two
mating males come close to one another, they become agitated and instantly try to fend off the
contender with their legs (B. Kneubühler pers. comm., IV.2016).
Table 1. Measurements [mm] of Nuichua rabaeyae gen. et sp. nov.
Length of HT ♂ PT ♂♂ PT ♀♀
Body 60.6 53.7–65.2 98.6–113.6
Head 4.5 3.5–4.1 7.1–7.9
Pronotum 3.8 3.1–3.9 6.3–6.9
Mesonotum 15.2 12.4–15.0 24.0–28.1
Metanotum 4.8 4.3–5.1 7.3–8.9
Median segment 3.2 3.2–3.6 5.6–6.4
Profemora 16.3 13.7–17.1 20.9–25.8
Mesofemora 12.1 10.2–11.9 15.9–19.5
Metafemora 15.6 13.8–16.5 20.7–26.5
Protibiae 18.5 14.7–18.8 22.6–27.4
Mesotibiae 12.3 10.3–12.5 16.3–19.0
Metatibiae 18.8 15.6–18.9 23.7–29.1
DISTRIBUTION. Southern Central Vietnam, Ninh Thuan Province (Fig. 8).
Belgian Journal of Entomology 70: 1–29 (2018)
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Fig. 8. Nuichua rabaeyae sp. nov. and Pterohirasea nigrolineata sp. nov., distribution map.
BRESSEEL J. & CONSTANT J. New Vietnamese stick insects: Nuichua and Pterohirasea (Phasmida: Necrosciinae)
18
Genus Pterohirasea gen. nov.
urn:lsid:zoobank.org:act:A2F38FB4-B0A0-4E2E-8769-A4FFCE554D18
Type species: Pterohirasea nigrolineata sp. nov. by present designation and monotypy.
ETYMOLOGY. The genus name is the combination of ptero-, from the Greek word pteron
meaning wing, and -hirasea, the ending of Neohirasea Rehn, 1904, illustrating the close
relationship between the two genera.
DIAGNOSIS
The genus is closely related to Nuichua gen. nov. but can be distinguished by the following
characters:
1) Comparatively longer legs; legs completely unarmed and mesofemora not swollen (Figs
10A–C, 12 A–C).
2) Posternum with rough paired, almost circular sensory areas (Fig. 9).
3) Tegmina absent; small alae present (Figs 10 D, G, 12 D, H, 13 H, L).
4) Poculum strongly rounded with outer margin curving downwards (Fig. 10 F, H–I).
5) Vomer with basal portion very broad, flattened and almost semicircular; posterior portion
tapering, strongly upcurving and with two blunt terminal hooks (Fig. 11).
6) Subgenital plate in females slightly projecting over apex of abdomen (Fig. 12 E–G).
DESCRIPTION
MALE AND FEMALE (Figs 10, 12)
Head: longer than wide and mainly smooth, except few distinct, pale granules dorsally and on
genae. Dorsal surface slightly flattened with distinct mediolongitudinal groove. Vertex
rounded, posterolaterally also with a groove. Eyes circular and strongly projecting
hemispherically followed by a broad dark postocular line. Antennae distinctly projecting over
front legs. Scapus slightly flattened dorsoventrally and oval in cross-section. Pedicellus short,
knob-like and round in cross-section.
Thorax: pronotum slightly shorter than head with few pale granules. Anterior margin strongly
incurved with anterolateral angles extended and apically rounded. Base of anterolateral
extensions with a minute pseudoforamen. Median longitudinal groove starting anteriorly, not
reaching posterior edge. Centrally with a short transverse impression not reaching lateral
edges. Posterior margin rounded. Mesonotum with few pale granules and parallel-sided.
Metanotum with few pale granules, slightly longer than median segment, subapically with a
small hump, followed by a short transverse furrow medially. Prosternum with anterior margin
straight, widening toward the posterior; posterior margin concave. Posternum with rough,
paired, almost circular sensory organs; longitudinally divided by a median furrow.
Wings: tegmina absent. Alae small, reduced, not reaching median segment; costal area
blackish with reddish margin; anal area bright red.
Legs: profemora compressed and curved basally. All carinae present and unarmed;
medioventral carina indistinct. Meso- and metafemora with carinae and armature as in
profemora (female) or ventral carinae indistinct (male). Protibiae subrectangular in cross-
section with outer ventral and dorsal carinae developed. Meso- and metatibiae with carinae as
in protibiae, with medioventral carinae present but indistinct. Meso- and metatarsi with claws
small when compared to body size; tarsomeres with a small posteromedian extension.
Abdomen: median segment longer than wide, slightly trapezoidal and subapically with a
small, black transverse hump medially. All abdominal terga less than two times longer than
wide (males) or transverse (females), with few pale granules. Terga II–IX with a small
Belgian Journal of Entomology 70: 1–29 (2018)
19
posteromedian hump. Males with anal segment shorter than IX, tectiform with
mediolongitudinal carina; slightly concave apically with outer margin slightly setose; ventral
portion of outer margin of anal segment slightly swollen and armed with several black
tubercles; posterolateral angles rounded. Poculum rounded; posterior margin flattened with
outer rim curving downwards; reaching about base of vomer. Cerci reaching about apex of
abdomen, laterally flattened with apices rounded, slightly incurving and distinctly setose.
Vomer well developed and large; basal portion broad, flattened and almost semicircular;
posterior portion tapering, strongly upcurving and notched apically, forming two blunt apices.
Apices blackish and tapering towards the posterior. Females with anal segment about as long
as tergum IX, tectiform with mediolongitudinal carina and broadly rounded apically;
abdominal sternum VII with definite praeopercular organ; broadened at base, later tapering
and resulting in a single spine. Subgenital plate reaching about apex of abdomen; laterally
flattened basally, later spoon-shaped and tapering posteriorly; posterior portion with a definite
median longitudinal carina.
EGG (Fig. 13 O–Q).
Capsule oval, brownish with darker markings and a reticulate structure; reticulum on capsule
surface covered with minute stalked granules. Polar area with dark marking. Operculum oval
and convex; coloured as capsule with several mushroom-shaped, stalked granules, more
densely grouped in the central portion. Micropylar plate positioned almost centrally on
capsule, slightly displaced towards polar area and almost circular. Micropylar cup black and
distinct, followed anteriorly by a definite mediolongitudinal carina.
DISTRIBUTION. Central Vietnam.
Pterohirasea nigrolineata sp. nov.
urn:lsid:zoobank.org:act:08146329-89F9-4C44-AD0D-6A120A5BEC84
Figs 8–14
ETYMOLOGY. The species name is derived from niger (adj., Latin) meaning black, and
lineatus (adj., Latin) meaning striped. It refers to the black longitudinal stripe marking the
body of the species.
TYPE MATERIAL. VIETNAM: holotype ♂ (Fig. 10): C Vietnam, Bach Ma N. P., 16°12’N
107°52’E, 12–17.VII.2011, leg. J. Constant & J. Bresseel, I.G.: 31.933 (RBINS).
Paratypes [20♂♂, 20♀♀, 4♀♀ penultimate stage, 2 nymphs]: 1♂, 3♀♀, 4♀♀ nymphs
penultimate stage: C Vietnam, Bach Ma N. P., 16°12’N 107°52’E, 12–17.VII.2011, leg. J.
Constant & J. Bresseel, I.G.: 31.933 (2♀♀, 2♀♀ nymphs penultimate stage: RBINS; 1♂, 1♀,
2♀♀ nymphs penultimate stage: VNMN); 1♂, 2♀♀: Vietnam, Thua Thiên-Huê Prov., Phong
Dien near VNMN station, 16°35’12”N 107°20’31’’E, 8-9.IV.2017, leg. J. Constant & J.
Bresseel, I.G.: 33.447 (RBINS); 1♂ Vietnam, Thua Thiên-Huê Prov., Bach Ma N.P., 16°12’N
107°52’E 10-16.IV.2017, leg. J. Constant & J. Bresseel, I.G.: 33.447 (RBINS); 15♂♂, 15♀♀:
ex breeding Tim Bollens 2018, origin: Vietnam, Thua Thiên-Huê Prov., Phong Dien near
VNMN station, 16°35’12”N 107°20’31’’E, 8-9.IV.2017, leg. J. Constant & J. Bresseel, I.G.:
33.447 (11♂♂, 11♀♀: RBINS; 4♂♂, 4♀♀: VNMN); 3♂♂: Annam, Lién Chién près
Tourane, 0 à 1000 M d’alt., Mme Poilane, 1923 (MNHN).
NOTE
Tourane is the older name of Da Nang, hence the location name “Lién Chién” is most
probably a misspelling of Liên Chiểu (coordinates: 16°07′26″N 108°07′4″E)
BRESSEEL J. & CONSTANT J. New Vietnamese stick insects: Nuichua and Pterohirasea (Phasmida: Necrosciinae)
20
Fig. 9. Pterohirasea nigrolineata sp. nov., prosternal sensory organs.
ADDITIONAL MATERIAL. VIETNAM: 75 eggs: ex breeding J. Bresseel, 2017, origin: Vietnam,
Thua Thiên-Huê Prov., Phong Dien near VNMN station, 16°35’12”N 107°20’31”E, 8-
9.IV.2017, leg. J. Constant & J. Bresseel, I.G.: 33.447 (50 eggs: RBINS; 25 eggs: VNMN).
ADDITIONAL DATA. VIETNAM: several nymphs (not collected): Da Nang Province, Ba Na-
Nui Chua Nat. Res., 16°00’N 108°01’E, 16-19.VII.2017, J. Constant & J. Bresseel.
DESCRIPTION
MALE (Figs 10–11, 13 C–I, 14 A–C)
Measurements: see table 2.
Body: (Fig. 10 A–C) head orange- to dark brown with paler granules; broad black postocular
line and a dark marking dorsally. Antennae black with white rings. Pro-, meso and metanotum
orange- to dark brown with paler granules and a broad black mediolongitudinal line. Median
segment and abdominal terga II–VII brown with a broad, black longitudinal line; sometimes
present on all segment excluding anal segment. Terga II–IX with a pale marking
anterolaterally. Legs orange- to dark brown. Coxae with a yellowish marking posteriorly,
femora and tibiae with minute pale markings. Meso- and metapleura with a definite yellow
marking. Thoracical and abdominal sterna cream to light brown with posteromedian black
marking.
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Fig. 10. Pterohirasea nigrolineata sp. nov., holotype ♂. A, habitus, dorsal view. B, habitus, lateral view.
C, habitus, ventral view. D, head and thorax, dorsal view. E, terminalia, dorsal view. F, terminalia ventral view.
G, head and thorax, lateral view. H, terminalia, ventral view. I, terminalia, lateral view.
BRESSEEL J. & CONSTANT J. New Vietnamese stick insects: Nuichua and Pterohirasea (Phasmida: Necrosciinae)
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Fig. 11. Pterohirasea nigrolineata sp. nov., ♂ vomer. A, ventral view. B, detail of apex. C, lateral view.
Head: (Figs 10 D, G, 14 C) longer than wide and mainly smooth, with few distinct, pale
granules dorsally and on genae; dorsal surface slightly flattened with distinct
mediolongitudinal groove. Vertex rounded, posterolaterally also with a groove. Between eyes,
a small raised area; anteriorly of raised area a shallow indention. Eyes circular and strongly
projecting hemispherically. Antennae distinctly projecting over front legs. Scapus slightly
flattened dorsoventrally and oval in cross-section. Pedicellus short, knob like and round in
cross-section.
Thorax: (Figs 10 D, G, 13 H, 14 C) pronotum slightly shorter than head with few pale
granules; anterior margin strongly incurved with anterolateral angles extended and apically
rounded. Base of anterolateral extensions with a minute peudoforamen. Posterior portion
slightly widening towards posterior margin. Median longitudinal groove starting anteriorly,
not reaching posterior edge. Centrally with a short transverse impression not reaching lateral
edges. Posterior margin rounded. Mesonotum about as long as mesofemora, with few pale
granules and parallel-sided. Metanotum with few pale granules, slightly longer than median
segment, subapically with a small hump followed by a short transverse median furrow.
Prosternum with anterior margin straight, widening towards the posterior; posterior margin
concave. Prosternum with rough paired, almost circular sensory organs; longitudinally
divided by a median furrow (Fig. 9). Mesosternum with few, minute pale tubercles laterally.
Meso- and metasternum with a small, black elevation posteriorly.
Wings: (Figs 10 D, G, 13 H, 14 C) tegmina absent. Alae small, not reaching median segment;
costal area blackish with inner margin reddish; anal area bright red.
Legs: (Fig. 10 A–C) profemora slightly longer than pro- and mesonotum combined;
compressed and curved basally; outer dorsal and ventral carinae present and unarmed;
medioventral carina indistinct. Mesofemora about as long as mesonotum; ventral carinae
indistinct. Metafemora slightly longer than profemora, armature as in mesofemora. Protibiae
slightly longer than head, pro- and mesonotum combined; subrectangular in cross-section
with outer ventral and dorsal carinae developed; carinae with small setae. Probasitarsus longer
than all following tarsomeres combined. Mesotibiae slightly longer than mesofemora; carinae
as in protibiae, with medioventral carinae present, but indistinct. Metatibiae distincly longer
than metafemora; carinae as in mesotibiae. Meso- and metatarsi with claws small when
compared to body size; tarsomeres with a small posteromedian extension.
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Fig. 12. Pterohirasea nigrolineata sp. nov., paratype ♀. A, habitus, dorsal view. B, habitus, lateral view.
C, habitus, ventral view. D, head and thorax, dorsal view. E, terminalia, dorsal view. F, terminalia, ventral view.
G, terminalia, lateral view. H, head and thorax, lateral view.
BRESSEEL J. & CONSTANT J. New Vietnamese stick insects: Nuichua and Pterohirasea (Phasmida: Necrosciinae)
24
Abdomen: (Figs 10 A–C, E–F, H–I, 13 I) median segment longer than wide, slightly
trapezoidal and subapically with a black transverse hump medially. All abdominal terga less
than two times longer than wide with few pale granules. Terga II–IX with a minute
posteromedian hump; tergum II slightly longer than median segment; III–V about the same
length; tergum VII distinctly shorter than V, widening towards the posterior; VIII distinctly
wider than long, widening posteriorly with a mediolongitudinal carina; tergum IX slightly
shorter than VIII and tectiform; tergum X shorter than IX with mediolongitudinal carina;
slightly concave apically with outer margin slightly setose. Ventral portion of outer margin of
anal segment slightly swollen and with several black tubercles. Posterolateral angles rounded.
Poculum rounded; posterior margin flattened with outer rim curving downwards; reaching
about base of vomer. Cerci reaching about apex of abdomen, laterally flattened with apices
rounded, slightly incurving and distinctly setose. Vomer well developed and large; basal
portion broad, flattened and almost semicircular; posterior portion tapering, strongly
upcurving and notched apically, forming two apices; apices blackish and tapering towards a
fairly blunt apex (Fig. 11).
FEMALE (Figs 12, 13 J–N, 14 D–F)
Measurements: see table 2.
Body: (Fig. 12 A–C) colouration as in male, distinctly paler ventrally.
Head: (Figs 12 D, H, 14 D) longer than wide and mainly smooth, with few distinct granules
dorsally and on genae. Dorsal surface slightly flattened with distinct mediolongitudinal
groove. Vertex rounded, posterolaterally also with a short groove. Eyes circular and strongly
projecting hemispherically. Antennae distinctly projecting over front legs. Scapus slightly
flattened dorsoventrally and oval in cross-section. Pedicellus short, knob-like and round in
cross-section.
Thorax: (Figs 12 D, H, 13 L, 14 D) pronotum slightly shorter than head, slightly widening
towards the posterior and sparsely granulose. Anterior margin strongly incurved with
anterolateral angles extended and apically rounded. Base of anterolateral extensions with a
minute peudoforamen. Median longitudinal groove starting anteriorly, not reaching posterior
edge. Centrally with a short transverse impression not reaching lateral edges. Posterior margin
rounded. Mesonotum distinctly longer than mesofemora, with scattered pale granules and
parallel-sided. Metanotum with few pale granules, slightly longer than median segment,
subapically with a median small hump, followed by a short transverse furrow. Prosternum
with anterior margin straight, widening towards the posterior; posterior margin concave.
Posternum with rough paired, almost circular sensory organs; longitudinally divided by a
median furrow. Meso- and metasternum smooth.
Wings: (Figs 12 D, H, 13 L) tegmina absent. Alae small, not reaching median segment; costal
area blackish with inner margin reddish; anal area bright red.
Legs: (Fig. 12 A–C) profemora shorter than mesonotum and half the pronotum combined;
compressed and curved basally; all carinae present and unarmed; medioventral carina
indistinct. Mesofemora shorter than mesonotum; ventral carinae indistinct. Metafemora
slightly longer than profemora and unarmed. Protibiae slightly longer than profemora;
subrectangular in cross-section and with outer ventral and dorsal carinae developed; carinae
with small setae. Probasitarsus about as long as the following three tarsomeres combined.
Mesotibiae about as long as mesofemora, with carinae as in protibiae, but with medioventral
carinae present. Metatibiae distinctly longer than protibiae; carinae as in mesotibiae. Claws
small when compared to body size; tarsomeres with a small posteromedian extension.
Abdomen: (Figs 12 A–C, E–G, 13 M–N) median segment wider than long, slightly trapezoidal
and subapically with a faint transverse hump medially. All abdominal terga transverse with
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25
few minute granules. Terga II–IX with faint median hump subapically, median hump more
definite in terga VI–IX; tergum II about as long as median segment; III–VI about the same
length; tergum VII slightly shorter than VI, trapezoidal, widening towards the posterior and
with a small lobe dorsolaterally; VIII about the same length as VII, trapezoidal and narrowing
towards the posterior; tergum IX distinctly shorter than VIII and tectiform. Anal segment
about the same length as tergum IX, tectiform with mediolongitudinal carina and truncate
apically. Abdominal sternum VII with definite praeopercular organ. Praeopercular organ
broad at base, later tapering and resulting in a single spine. Subgenital plate reaching about
apex of abdomen; apical half spoon-shaped and tapering posteriorly; posterior portion with a
definite median longitudinal carina. Other abdominal sterna smooth with a small black
marking posteromedially.
NYMPH (Figs 13 A–B, 14 G)
Head orange with black postocular line. Antennae black and white. Body olivaceous brown
with minute white spots; abdominal terga with anterolateral white markings; legs coloured as
body with apical portion of femora orange and trochanters and coxae white.
EGG (Fig. 13 O–Q)
Measurements (in mm). Length: 3.2; width: 2.2; height: 2.6.
Capsule oval, coloured brownish with darker markings and a reticulum; reticulum on capsule
surface covered with minute stalked, cream granules. Polar area with dark marking; marking
tapering towards and reaching and continuing on micropylar plate. Operculum oval and
convex; coloured as capsule with several mushroom-like, stalked granules, more densely
grouped in central portion. Micropylar plate positioned almost centrally on capsule, slightly
displaced towards the polar area; almost circular, slightly darker than capsule; surface smooth;
outer margin with few, minute whitish granules. Micropylar cup black and distinct, followed
anteriorly by a definite mediolongitudinal carina.
BIOLOGY. Adults (Fig. 14 A–F) and nymphs (Fig. 14 G) were collected in tropical evergreen
rainforest (Fig. 14 H), at low to medium altitude (250–800 m). The specimens were observed
on lower vegetation. In captivity, eggs are dropped to the ground and a wide variety of
alternative foodplants including Hypericum spp. (Hypericaceae) and different species of
Rubus spp. (Rosaceae) were accepted.
When disturbed, they open their wings to show the bright red part of the alae as a defensive
behaviour (Fig. 13 G–H).
Table 2. Measurements [mm] of Pterohirasea nigrolineata gen. et sp. nov.
Length of HT ♂ PT ♂♂ PT ♀♀
Body 51.4 62.4–67.0 68.2–81.4
Head 4.0 4.5–4.7 5.3–6.8
Pronotum 4.3 4.5–5.0 5.8–6.2
Mesonotum 11.5 13.5–15.4 15.0–18.3
Metanotum 3.3 4.0–4.6 4.0–5.2
Median segment 3.1 3.5–3.8 3.7–4.6
Profemora 15.1 18.0–18.6 16.2–21.3
Mesofemora 11.9 14.1 12.9–16.2
Metafemora 16.6 20.3–21.7 18.6–24.4
Protibiae 19.0 20.7–22.5 17.8–22.8
Mesotibiae 14.0 15.9–16.7 13.6–18.6
Metatibiae 21.8 24.7–27.3 21.6–28.1
DISTRIBUTION. Central Vietnam, provinces of Thua Thien-Hue and Da Nang (Fig. 8).
BRESSEEL J. & CONSTANT J. New Vietnamese stick insects: Nuichua and Pterohirasea (Phasmida: Necrosciinae)
26
Fig. 13. Pterohirasea nigrolineata sp. nov. A–N, captive reared, from Phong Dien VNMN Station (photographs
by J. Constant). A–B, nymph. C, ♂, dorsal view. D, ♂, lateral view. E, ♂, head and thorax. F, ♂, dorsal view.
G, ♂, lateral view. H, ♂, head and thorax. I, ♂, abdomen ventral view. J, ♀, dorsal view. K, ♀, lateral view.
L, ♀, head and thorax dorsal view. M, ♀, abdomen ventral view. N, ♀, terminalia dorsal view. O, newborn
nymph (photograph by T. Bollens). P–R, egg. P, lateral view. Q, dorsal view. R, operculum.
Belgian Journal of Entomology 70: 1–29 (2018)
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Fig. 14. Pterohirasea nigrolineata sp. nov., wild specimens and habitat in Bach Ma N.P. (photographs A–G by
J. Constant, H by H.T. Pham). A–C, ♂, 12.VII.2011. D–F, ♀, 17.VII.2011. G, subadult nymph, 12.VII.2011.
H, habitat in Bach Ma N.P, 12.VII.2011.
BRESSEEL J. & CONSTANT J. New Vietnamese stick insects: Nuichua and Pterohirasea (Phasmida: Necrosciinae)
28
Discussion
Together with the new taxa described herein, the total number of Necrosciinae in Vietnam
now reaches 23 genera and 60 species. The two new genera are closely related and share a
number of characters e.g. relatively stout body; subgenital plate in females relatively flat,
more or less spoon-shaped with a longitudinal median carina in apical half; eggs with capsule
more or less round to oval, capitulum rounded to conical, micropylar plate bearing a
mediolongitudinal ridge; no specialised egg laying method with eggs dropped to the ground;
males with a distinct, often specialised vomer. These common characters of both genera, also
place them close to Oxyartes Stål, 1875, Neohirasea Rehn, 1904 and a number of genera that
were grouped in the tribe Neohiraseini Hennemann & Conle, 2008 by HENNEMANN & CONLE
(2008) and HO et al. (2014). The latter tribe was originally included in the subfamily
Lonchodinae following the generic classification at that time. Based on molecular analysis,
BRADLER et al. (2014) transferred Neohirasea to the subfamily Necrosciinae, which
comprises only the tribe Necrosciini. Consequently, the tribe Neohiraseini automatically
became a junior synonym of Necrosciini. However, the morphological characters as listed
above, as well as the phylogenetic trees provided by BRADLER et al. (2014) support a
consistent clade within the Necrosciinae which includes the Neohiraseini sensu HENNEMANN
& CONLE (2008) + Oxyartes and some further closely related taxa (e.g. Phaenopharos Kirby,
1904, Paramenexenus Redtenbacker, 1908, Phamartes Bresseel & Constant, 2013 and
Pseudoparamenexenus Ho, 2016). Further study integrating molecular data of more taxa,
morphological characters of adults and eggs and behavioural data needs to be conducted to
assess the relevance of the resurrection of the tribe Neohiraseini within the Necrosciinae.
The presence of rough sensory areas on the prosternum and profurcasternum was considered
an autapomorphy of Heteropterygidae by HENNEMANN et al. (2016). A similar structure has
been observed for the first time in Necrosciinae, in Pterohirasea gen. nov. Further
examination of putatively closely related genera, e.g. Neohirasea, Andropromachus,
Spinohirasea and Brockphasma has shown that this character cannot be considered an
autapomorphy of Neohiraseini sensu HENNEMANN & CONLE (2008) as it is not present in all
genera and can even be present or absent in different species of the same genus as observed in
Neohirasea. Additional study of those structures appears necessary to clarify their function
and their relevance as a taxonomically useful character within Necrosciinae.
The sexual dimorphism in terms of size observed in Nuichua rabaeyae sp. nov. with the
males being almost 50% shorter than females, is very strong compared to that in Pterohirasea
nigrolineata sp. nov., with males only about 15% shorter than females. A hypothesis for this
sexual dimorphism may be related to sexual selection in connection with the behaviour
consisting, for the males reaching adulthood as first, to mate with and keep subadult females.
This process may have induced the selection of the fastest growing males, i.e. those reaching
maturity with the smallest size. This hypothesis is further supported by the fact that the male
remains attached to the same female for all his life.
Acknowledgments
We thank Dr Hong Thai Pham (VNMN) and Mr Vu Tru Hoang (Institute of Ecology and Biological Resources,
Hanoi, Vietnam) for all their help and friendship during the collecting trips; Mr. Olivier Gengoux and Mrs.
Daphné Lê (Beersel, Belgium) for their help and company in the field in Nui Chua N.P.; Dr Bruno Kneubühler
(Lucerne, Switzerland) and Mrs Mieke Duytschaever (Essen, Belgium) for sharing their excellent pictures and
observations; Mr Tim Bollens (Herselt, Belgium), Mrs Kristien Rabaey and Mr Rob Simoens (Veurne, Belgium)
for their help in captive rearing the species and providing additional study material; Mr Ludovic Nicolas (SRBE)
for mounting numerous specimens we brought back from the field; the authorities of the sampled areas in
Belgian Journal of Entomology 70: 1–29 (2018)
29
Vietnam who supported our studies; Dr Patrick Grootaert, Dr Yves Samyn and Dr Marie-Lucie Susini (RBINS)
for their permanent support to our projects in Vietnam; Mr Oskar Conle (Duisburg, Germany) and Mr Frank
Hennemann (Freinsheim, Germany) for their valuable comments, which greatly improved our work; Dr Douglas
Yanega (University of California, Riverside, U.S.A.) for his advice on higher nomenclature; Mr Gontran Sonet
for his expertise in the interpretation of molecular data based phylogenies. This paper is a result of the project “A
step further in the Entomodiversity of Vietnam” supported through a grant issued by the capacity building
Programme of the Belgian Global Taxonomic Initiative National Focal Point that runs under the CEBioS
programme with financial support from the Belgian Directorate-General for Development Cooperation (DGD).
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