A new genus and three new species of the subfamily Phygadeuontinae (Hymenoptera: Ichneumonidae) from northern Vietnam

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Eu opean Jou nal o Taxonomy 1026: 236–249
h ps://doi.o g/10.5852/ej .2025.1026.3119
eu opeanjou nalo axonomy.eu
ISSN 2118-9773
2025 · Pham N.T. & Cao N.T.
This wo k is licensed unde a C ea i e Commons A ibu ion License (CC BY 4.0)
Recei ed: 20 May 2025 • Accep ed: 16 Sep embe 2025 • Published: 21 No embe 2025
Topic edi o : Tony Robilla d • Sec ion edi o : Ga in B oad • Desk edi o : Lize h Alonso
Resea ch a icle
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A new genus and h ee new species o he sub amily Phygadeuon inae
(Hymenop e a: Ichneumonidae) om no he n Vie nam
Nhi Thi PHAM1,*  & Nga Thi Quynh CAO2 
1,2 Ins i u e o Biology, Vie nam Academy o Science and Technology, 18 Hoang Quoc Vie ,
Hanoi, Vie nam.
* Co esponding au ho : [email p o ec ed]
2 Email: cqnga1[email p o ec ed]
Abs ac . A new Da win wasp genus, Longipec us gen. no ., is desc ibed om no he n Vie nam o
include h ee new species Longipec us hagiangensis gen. e sp. no ., Longipec us planus gen. e sp. no .,
and Longipec us yagi gen. e sp. no . Mo phologically, he new genus Longipec us di e s om o he
phygadeuon ine gene a by he combina ion o he globula head, he long mesosoma, he long no auli,
hesho  i s  e gi e,and helongi udinalw inkleson he i s andsecond e gi es.
Key wo ds. Da win wasp, pa asi oid, axonomy.
Pham N.T. & Cao N.T.Q. 2025. A new genus and h ee new species o he sub amily Phygadeuon inae
(Hymenop e a: Ichneumonidae) om no he n Vie nam. Eu opean Jou nal o Taxonomy 1026: 236–249.
h ps://doi.o g/10.5852/ej .2025.1026.3119
In oduc ion
The sub amily Phygadeuon inae Fö s e , 1869 consis s o 125 gene a wi h nea ly 2000 species wo ldwide
(Yu e al. 2016; San os 2017; Pham e al. 2019; Reshchiko e al. 2019; Pham e al. 2020; Wa anabe
2021; Pham e al. 2024; Lima & Fe nandes 2024). This sub amily is mos di e se in empe a e egions
and can be dis inguished om he closely ela ed C yp inae by usually smalle body size, o ewing
c oss- ein 2m-cu usually dis inc ly incli ous wi h wo bullae, and he s e naulus ending abo e he en o-
pos e io co ne o he mesopleu on (San os 2017).
Membe s o Phygadeuon inae pa asi ize small cocoons o cocoon-like s uc u es. Cocoons o many
holome abolous insec g oups ha e been eco ded as hos s o phygadeuon ine species such as
Lepidop e a, Hymenop e a, Coleop e a, Dip e a, as well as egg sacs o spide s. Some species a e also
eco ded as seconda y pa asi oids (Townes 1970; Wahl & Sha ke 1993). Since he seminal wo k o
Townes (1970), no less han 20 gene a and mo e han 650 species ha e been desc ibed as new wi hin
his sub amily, o which wo gene a and 84 species we e disco e ed om he O ien al egion (Yu e al.
2016; Pham e al. 2019, 2020, 2024; Reshchiko e al. 2019; Wa anabe 2021; Lima & Fe nandes 2024).
Tha means axonomic s udies o Phygadeuon inae, pa icula ly in he O ien al egions, a e emendously
PHAM N.T. & CAO N.T.Q., Longipec us, a new genus o Ichneumonidae om Vie nam
237
sca ceandin aluable.Thiswo kaims odesc ibeanewgenuso Phygadeuon inae, he i s  o  he
O ien al egion since he disco e y o he genus Ca ini yla Sheng & Sun, 2010, and o p opose h ee
new species on he basis o specimens om no he n Vie nam.
Ma e ial and me hods
Thousands o ichneumonid wasps we e collec ed in no he n Vie nam om 2013 o 2024 by Malaise
aps and sweep ne s, howe e , e y ew specimens a e used in his s udy due o hei sca ci y in ou
scien i iccollec ion;Theya edeposi eda  heIns i u eo Biology(IB),Vie namAcademyo Science
and Technology, Hanoi, Vie nam.
Mo phological e minology ollows B oad e al. (2018). Pho og aphs we e aken wi h a Nikon SMZ800N
M80 s e eo mic oscope and an Olympus SZX 16 s e eo mic oscope, and subsequen ly s acked wi h
Helicon Focus.
Abb e ia ions used in ex
F1, F2, F3, ...Fn = Flagellome e 1s , 2nd, 3 d, ...n
T1, T2, T3, ...Tn = Me asomal e gi e 1, 2, 3, ...n
Resul s
Taxonomy
Class Insec a Linnaeus, 1758
O de Hymenop e a Linnaeus, 1758
Supe amily Ichneumonoidea La eille, 1802
Family Ichneumonidae La eille, 1802
Sub amily Phygadeuon inae Fö s e , 1869
Genus Longipec us gen. no .
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Diagnosis
Head globula ; occipi al ca ina widely sepa a ed om pos e io ocelli, en ally mee ing hypos omal
ca ina abou 0.6–1.0 × basal mandibula wid h om base o mandible; mesosoma elonga e and do so-
en ally comp essed, 0.7–0.8 × as long as me asoma, wi h no auli dis inc on an e io 0.5–0.7 o
mesoscu um; mesopleu on wi h epis e nal sc obe connec ed o mesopleu al u ow by a g oo e; pos e io
anse e se ca ina o mesos e num sho and -shaped; p opodeum wi h a ea pe iola is sepa a ed om
a easupe omediawhen hela e de ined; i s  e gi esho ,abou 0.4–0.7× as long as second e gi e,
wi h en ola e alca inacomple e; i s andsecond e gi eswi hlongi udinalw inkles;me asomal
e gi es 2 and 3 wi h la e o e gi e sepa a ed by dis inc su u e; o iposi o ela i ely slende .
E ymology
The name o he new genus is de i ed om he La in wo ds ‘longus’, meaning ‘long’, and ‘pec us’,
meaning ‘ ho ax’, e e ing o i s long ho ax. Gende : masculine.
Type species
Longipec us yagi gen. e sp. no .
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Desc ip ion
Head globula . Occipi al ca ina hickened, comple e and widely sepa a ed om pos e io ocelli, en ally
mee ing hypos omal ca ina abou 0.6–1.0 × basal mandibula wid h om base o mandible. Face as
high as wide o highe han wide. Clypeal su u e indis inc . Mandible sho , 2.0–2.5 × as long as median
wid h, weakly o dis inc ly na owed owa ds apex, ee h sha p. Maxilla y palp long o mode a ely long,
eachingan e io  ocen e pa o mesopleu on.Basal lagellome eslongandna ow,F17.0–11.0×
as long as wide. Mesosoma 0.7–0.8 × as long as me asoma. P ono um 0.3–0.4 × as long as mesosoma,
epomia absen o p esen as a sho s ub, do so-medially o p ono um, jus behind p ono al colla wi hou
o wi h weak median ca ina. Mesoscu um 1.2–1.9 × as long as maximum wid h. No auli dis inc on
an e io 0.5–0.7 o mesoscu um. Scu ellum weakly o mode a ely con ex, la e al ca ina p esen basally.
Mesopleu on wi h epicnemial ca ina p esen en ally o do sally, s e naulus p esen o absen , epis e nal
sc obe connec ed o mesopleu al u ow by a g oo e. Pos e io ans e se ca ina o mesos e num
sho and -shaped. P opodeum g adually sloping in la e al iew, a ea pe iola is sepa a ed om a ea
supe omediawhen hela e de ined,p opodealspi aclesmalland ound.T1sho ,0.4–0.7× as long as
T2, polished, do sola e al and en ola e al ca inae dis inc . T1–T2 wi h longi udinal w inkles. T2–T3
wi h la e o e gi es sepa a ed by dis inc su u es. O iposi o hin, s aigh , lowe al e wi h ee h apically.
O iposi o shea h 0.18–0.38 × as long as hind ibia leng h. Legs long, hind emu 5.3–6.2 × as long as
wide, hind a sus longe han hind ibia, hind basi a sus nea ly 0.5 × as long as hind a sus. Fo e wing
leng h 3.5–5.1 mm, ein 3 s-m absen , ein 2m-cu incli ous, wi h wo bullae.
Key o species o Longipec us gen. no .
1. Mesosoma ex emely elonga e, 0.8 × as long as me asoma (Fig. 6); p ono um 0.4 × as long as
mesosoma (Fig. 7E); p opodeum wi h densely ans e se s ia ions do sally (excep smoo h
pos e io ly), a ea supe omedia absen , pos e io ans e se ca ina o ming a c es (Fig. 7H);
o e wing smoky medially (Figs 6, 7G) …………………………………L. yagi gen. e . sp. no .
– Mesosoma less elonga e, abou 0.7 × as long as me asoma (Figs 1, 3); p ono um 0.3 × as long
asmesosoma(Figs2E,4E);p opodeumpunc a e oma ,a easupe omediaweaklyde inedo 
open la e ally, pos e io ans e se ca ina no mal; o e wing hyaline (Figs 2G, 4G) ………….2
2. An enna wi h no mally cylind ical lagellome es; s e naulus dis inc , eaching hind ma gin
o mesopleu on (Fig. 2E); p opodeum ma , a ea supe omedia weakly de ined (Fig. 2H);
o iposi o shea h 0.33–0.38 × as long as hind ibia leng h…...L. hagiangensis gen. e . sp. no .
–An ennawi hpos e io  lagellome es hickenedand la ened en ally;s e naulusindis inc 
(Fig. 4E); p opodeum punc a e, a ea supe omedia open la e ally (Fig. 4H); o iposi o shea h
0.18–0.19 × as long as hind ibia leng h ………................................ L. planus gen. e . sp. no .
Longipec us hagiangensis gen. e sp. no .
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Figs 1–2
Diagnosis
S e naulusdis inc , eachinghindma gino mesopleu on;a easupe omediaweaklyde ined;o iposi o 
shea h 0.33–0.38 × as long as hind ibia.
E ymology
Thespeci icname e e s oi s ypelocali y,HaGiangP o ince.
PHAM N.T. & CAO N.T.Q., Longipec us, a new genus o Ichneumonidae om Vie nam
239
Type ma e ial
Holo ype
VIETNAM•♀;HaGiangP o ince,QuanBadis ic ,TungVaicommune;23°03ʹ18ʺN,104°50ʹ44ʺE;
1340 m a.s.l.; 26 Ma .–14 Ap . 2024; N.T. Pham leg.; Malaise ap; IB.
Pa a ypes
VIETNAM•1♀;CaoBangP o ince,PhiaOac-PhiaDenNa ionalPa k;8–18May2013;T.H.
Phamleg.;Malaise ap;IB.•2♀♀;HaGiangP o ince,MeoVacdis ic ,ChiSan;23°09.53ʹN,
105°25.023ʹE;1149ma.s.l.;1Ap .–31May2024;N.T.PhamandN.T.Q.Caoleg;Malaise ap; IB.
Desc ip ion
Female
Head. Face 1.0 × as wide as high, g anula e, wi h se ae. Clypeal su u e indis inc . Clypeus 2.0 × as wide
as high, polished, spa sely punc a e, wi h se ae, en al ma gin weakly imp essed. Mandible sho and
s ou , 2.4 × as long as median wid h, weakly na owed owa ds apex, ee h sha p, uppe oo h longe
han lowe oo h. Mala space g anula e, 0.7 × as wide as mandibula basal wid h (Fig. 2A). Gena ma ,
wi h se ae. F ons and e ex ma , wi h se ae. Pos e o-ocella dis ance 1.2 × ocula -ocella dis ance, 0.8 ×
medianocellusdiame e (Fig.2B).An ennawi h32 lagellome es,F17.0×aslongaswide,1.1×as
long as F2. Occipi al ca ina comple e, en ally mee ing hypos omal ca ina abou 0.6 × basal mandibula
wid h om base o mandible.
Fig. 1. Longipec us hagiangensisgen.e sp.no .,holo ype,♀ (IB), habi us, la e al iew Scale ba = 1 mm.
Eu opean Jou nal o Taxonomy 1026: 236–249 (2025)
240
Fig. 2. Longipec us hagiangensisgen.e sp.no .,holo ype,♀ (IB). A. Head, on al iew. B. Head,
do sal iew. C. Head, la e al iew. D. Mesono um. E. Mesosoma, la e al iew. F. Me asomal e gi es.
G. Wings. H. P opodeum. K. O iposi o . Scale ba s: A–F, K = 0.2 mm; G = 0.5 mm.

PHAM N.T. & CAO N.T.Q., Longipec us, a new genus o Ichneumonidae om Vie nam
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MesosoMa. 0.7 × as long as me asoma (Fig. 1). P ono um 0.3 × as long as mesosoma, ma do sally,
pos e io co ne punc os ia e, wi h se ae, medially s ongly imp essed, subpolished, wi h s ia ions.
Epomia absen (Fig. 2E). Mesoscu um 1.4 × as long as i s maximum wid h, g anula e. No auli p esen on
an e io 0.5o mesoscu um.Scu ellummode a elyweaklycon ex, inelyg anula e,excep impunc a e
pos e io ly, la e al ca ina p esen basally (Fig. 2D). Mesopleu on ma , punc a e, wi h se ae; epicnemial
ca ina dis inc on en al 0.7 o mesopleu on. S e naulus dis inc , eaching hind ma gin o mesopleu on,
dis inc ly do sal o lowe pos e io . Me apleu on ma . Jux acoxal ca ina comple e (Fig. 2E). P opodeum
g aduallyslopinginla e al iew,ma ,excep a eape iola issmoo h.A easupe omediaweaklyde ined,
sepa a ed om a ea pe iola is (Fig. 2H). Spi acle small, ound.
Wings. Fo e wing leng h ca 3.6 mm, ein 1cu-a pos u cal o M&RS, cu ed, ein 3 s-m absen , ein
2 s-m sligh ly longe han leng h o M be ween 2 s-m and 2m-cu, leng h o CU be ween 1m-cu&M and
2cu-a 1.1 × leng h o 2cu-a. Hind wing wi h dis al abscissa o CU p esen , leng h o CU be ween M and
cu-a 1.3 × leng h o cu-a.
Legs. Hind coxa ma . Hind emu 5.6 × as long as i s maximum wid h, 0.8 × as long as hind ibia leng h.
Hind a sus 1.2 × hind ibia. Hind basi a sus 0.48 × as long as a sus.
Me asoMa. T1 and T2 subpolished, wi h longi udinal w inkles, T3 ma , wi h longi udinal w inkles
onan e io 0.75,T4onwa ds inelypunc a e.T12.5× as long as pos e io wid h, en ola e al ca ina
dis inc ; spi acle small, ound. T2 1.5 × as long as T1, 2.9 × as long as an e io wid h, 1.5 × as long as
pos e io wid h (Fig. 2F). O iposi o hin, s aigh , lowe al e wi h ee h apically (Fig. 2K); o iposi o
shea h 0.33 × as long as hind ibia.
CoLou . Black wi h eddish b own ma kings. Head black, scape en ally and mandible eddish b own,
palpi yellow. T2–T5 eddish b own apically, T6 onwa d eddish b own. Fo e and mid legs eddish b own,
excep coxae, ochan e s, ochan elli yellow. Hind leg la gely black excep ochan e and ochan ellus
yellow. Wings hyaline, wing eins b own.
Va ia ion
Pa a ypes wi h mala space om 0.6–0.8 × as long as mandibula basal wid h, mandible 2.0–2.5 × as
long as median wid h, hind emu a ies om 5.3–5.6 × as long as wide, 0.85–0.9× as long as hind ibia,
T1 2.3–2.5 × as long as pos e io wid h, T2 2.7–2.8 × an e io wid h, 1.4 × pos e io wid h, o iposi o
shea h 0.35–0.38 × hind ibia leng h. Pa a ype collec ed om Cao Bang P o ince has pos e o-ocella
dis ance 1.3 × ocula -ocella dis ance, 1.0 × median ocellus diame e , o e wing 3.8 mm long, leng h o
hind wing ein CU be ween M and cu-a 0.9 × leng h o cu-a.
Male
Unknown.
Dis ibu ion
Cu en ly known only om e e g een mon ane o es s in Ha Giang and Cao Bang p o inces, no heas e n
Vie nam.
Eu opean Jou nal o Taxonomy 1026: 236–249 (2025)
242
Longipec us planus gen. e sp. no .
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Figs 3–5
Diagnosis
An ennawi hF9onwa ds hickenedand la ened en ally;s e naulusindis inc ;a easupe omediaopen
la e ally; o iposi o shea h 0.18–0.19× as long as hind ibia.
E ymology
Thespeci icname‘planus’isaLa inadjec i emeaning‘ la ’, e e ing oi sdis ally la enedan enna.
Type ma e ial
Holo ype
VIETNAM•♀;CaoBangP o ince,PhiaOac-PhiaDenNa ionalPa k;22°36ʹ12ʺN,105°53ʹ10ʺE;
980 m a.s.l.; 30 Ap . 2022; D.D. T an leg.; Malaise ap; IB.
Pa a ypes
VIETNAM•1♀;HoaBinhP o ince,MaiChaudis ic ,HangKiacommune;1400ma.s.l.;10Oc .
2019;LongD.K.leg.;sweepne ;IB•1♂;SonLaP o ince,ThuanChaudis ic ,CoMacommune;
21°19ʹ2.2ʺN,103°35ʹ14.1ʺE; 1,591 m a.s. l.; 27 Ap .–2 May 2016; T.V. Hoang and B.V. Nguyen leg.;
Malaise ap; IB.
Fig. 3. Longipec us planus gen.e sp.no .,holo ype,♀(IB),habi us,la e al iew.Scaleba =1mm.
PHAM N.T. & CAO N.T.Q., Longipec us, a new genus o Ichneumonidae om Vie nam
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Fig. 4. Longipec us planus gen.e sp.no .,holo ype,♀(IB).A. Head, on al iew. B. Head, do sal
iew. C. Head, la e al iew. D. Mesono um. E. Mesosoma, la e al iew. F. Me asomal e gi es. G. Wings.
H. P opodeum. K. O iposi o . Scale ba s: A–E, H–K = 0.2 mm; F–G= 0.5 mm.
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244
Desc ip ion
Female
Head. Face 0.8 × as wide as high, g anula e, wi h se ae. Clypeal su u e indis inc . Clypeus 1.7 × as wide
as high, simila sculp u es as ace, en al ma gin weakly imp essed. Mandible sho , 2.5 × as long
as median wid h, g adually na owed owa ds apex, ee h sha p, uppe oo h longe han lowe oo h.
Mala space inelyg anula e,0.4×aswideasmandibula basalwid h(Fig.4A).Gena, onsand e ex
inelyg anula e,wi hse ae.Pos e o-ocella dis ance0.9×ocula -ocella dis ance,0.8×medianocellus
diame e (Fig.4B).An ennawi h26 lagellome es,F19.0×aslongaswide,1.2×aslongasF2, en al
sideo F9onwa ds la enedand hickened.Occipi alca inacomple e, en allymee inghypos omal
ca ina abou 1.0 × basal mandibula wid h om base o mandible.
MesosoMa.0.7×aslongasme asoma(Fig.3).P ono um0.3×aslongasmesosoma,polished, inely
g anula e an e io ly and pos e io ly, medially s ongly imp essed, smoo h. Epomia sho (Fig. 4E).
Mesoscu um 1.5 × as long as i s maximum wid h, g anula e. No auli p esen on an e io 2/3 o
mesoscu um.Scu ellummode a elycon ex, inelyg anula e,excep impunc a epos e io ly,la e al
ca inap esen basally(Fig.4D).Mesopleu on inelyg anula e,wi hse ae;epicnemialca inadis inc 
on en al0.7o mesopleu on.S e naulusindis inc .Me apleu on inelyg anula e.Jux acoxalca ina
absen (Fig. 4E). P opodeum g adually sloping in la e al iew, punc a e do sally, smoo h a le el o a ea
supe omediaanda eape iola is.A easupe omediaopenla e ally.A eape iola isde ined(Fig.4H).
Spi acle small, ound.
Wings. Fo e wing leng h ca 4.1 mm, ein 1cu-a in e s i ial o M&RS, weakly cu ed en ally, ein
3 s-m absen , ein 2 s-m sligh ly longe han leng h o M be ween 2 s-m and 2m-cu, leng h o CU
Fig. 5. Longipec us planusgen.e sp.no .,pa a ype,♂(IB). A. Habi us, la e al iew. B. Head, on al
iew. C. Head, do sal iew. D. P opodeum. E. Mesoscu um. Scale ba s: A = 1 mm; B–E = 0.2 mm.