JHR 77: 203-211 (2020) gee, JOURNAL OF Se veret pesca
doi: |0.3897/jhr.77.53323 RESEARCH ARTICLE ME Hymenoptera

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

A new species of genus Rhinotorus Forster
(Ichneumonidae, Ctenopelmatinae) parasitizing
Pristiphora erichsonii (Hymenoptera, Tenthredinidae)
and a key to Eastern Palaearctic species

Tao Li', Shu-Ping Sun', Mao-Ling Sheng!

| General Station of Forest and Grassland Pest Management, National Forestry and Grassland Administration,
58 Huanghe North Street, Shenyang 110034, China

Corresponding author: Mao-Ling Sheng (shengmaoling@163.com)

Academic editor: Gavin Broad | Received 17 April 2020 | Accepted 15 May 2020 | Published 29 June 2020
http://zoobank.org/2A131A72-D5A2-436C-BFEC-764ED43807CB

Citation: Li T, Sun S-P, Sheng M-L (2020) A new species of genus Rhinotorus Forster (Ichneumonidae, Ctenopelmatinae)
parasitizing Pristiphora erichsonii (Hymenoptera, Tenthredinidae) and a key to Eastern Palaearctic species. Journal of

Hymenoptera Research 77: 203-211. https://doi.org/10.3897/jhr.77.53323

Abstract

A new species of Ctenopelmatinae, Rhinotorus nigrus Sheng, Li & Sun, sp. nov. reared from cocoons of
Pristiphora erichsonii (Hartig) in Jilin Province, China, is described and illustrated. A key to Eastern Pal-
aearctic species of Rhinotorus is provided.

Keywords

Key, new species, Rhinotorus, Mesoleiini, taxonomy

Introduction

The larch sawfly, Pristiphora erichsonii (Hartig) (Hymenoptera, Tenthredinidae), has
been a significant pest of Larix spp. in China and other countries (Xiao 1992; Zhou
et al. 1995). It is distributed in the Palaearctic and Nearctic regions (Coppel and Leius
1955; Wong 1974; Richmond et al. 1975; Taeger et al. 2018). Parasitoids of this sawfly
include Diptera and Hymenoptera (Muldrew 1967; Zinnert 1969; Pschorn-Walcher

Copyright Tao Li et al. 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.

204 Tao Li et al. / Journal of Hymenoptera Research 77: 203-211 (2020)

and Zinnert 1971; Drooz 1975; Richmond et al. 1975; Drooz and Thompson 1986).
The parasitism rates of Olesicampe nematorum (Tschek) for P erichsonii about 61%
to 87% (Muldrew 1967), and the parasitism rate of Olesicampe benefactor Hinz for P
erichsonii reached over 90% in Minnesota (Kulman et al. 1974). In China, there are
about 16 species of parasitoids of this sawfly (Sheng and Chen 2001; Li et al. 2014;
Yang et al. 2015). The parasitism rates of parasitoids range from 15.9% to 31.5%
(Li et al. 2014). Parasitoids are playing an important role in terminating larch sawfly
outbreaks. In the present research a new parasitoid of Pristiphora erichsonii (Hatrtig),
belonging to the genus Rhinotorus Forster, 1869, was found.

Rhinotorus Forster (Hymenoptera, Ichneumonidae, Ctenopelmatinae) comprises
15 species (Reshchikov 2016; Yu et al. 2016), of which three are from the Eastern
Palaearctic Region (also found in the Western Palaearctic) (Meyer 1936; Townes et al.
1965; Reshchikov 2016), 14 from the Western Palaearctic (Reshchikov 2016), and one
from the Nearctic Region (Yu et al. 2016).

The species of Rhinotorus Forster were revised by Reshchikov (2016). Prior to the
present study the genus has not been recorded in China, nor from the Oriental Region.

The diagnostic characters of Rhinotorus were described by Townes (1970) and ex-
panded upon by Reshchikov (2016).

Nineteen host species of Rhinotorus from ten genera of Tenthredinidae have been
recorded, 17 of them belong to subfamily Nematinae (Yu et al., 2016). In the present
research parasitism of the genus Rhinotorus Forster, 1869 Pristiphora erichsonii (Hartig)
is recorded for the first time.

Material and methods

Institutional abbreviations

GSFGPM General Station of Forest and Grassland Pest Management, National For-
estry and Grassland Administration, P. R. China;

NHMUK_ Natural History Museum, London, United Kingdom;

ZISP Zoological Institute of the Russian Academy of Sciences, St. Petersburg,
Russia.

Specimen collection and rearing

Cocoons of sawflies were collected under naturally infested trees in Mt. Maoer, be-
longing to the branch of Mt. Changbai (42°50'N, 129°28’E, elevation 375 to 400 m),
Jilin Province. The forest stand is composed of mixed deciduous angiosperms mainly
Quercus mongolica Fischer ex Ledebour and shrubs, with evergreen conifers — Pinus ko-
raiensis Siebold et Zuccarini, P tabuliformis Carr., and with deciduous conifers — Larix
gmelinii (Rupr.) Kuzen., L. kaempferi (Lamb.) Carr., L. principis-rupprechtii Mayr. The
detail methods according to Li et al. (2014).

A new species of genus Rhinotorus Forster 205

Images were taken using a Leica M205A stereo microscope with LAS Montage

MultiFocus. Morphological terminology is mostly based on Broad et al. (2018). Type
specimens are deposited in the Insect Museum, GSFGPM.

Taxonomy

Rhinotorus Forster, 1869

Rhinotorus Forster, 1869: 211. Type-species: Spudaea longicornis Schmiedeknecht.

Key to the Eastern Palaearctic species of Rhinotorus

1

Third metasomal tergite without impression, granulate and impunctate. Coxae
yellowish red. Hind tibia black basally and apically and whitish centrally. All ter-
gites black. — Transpalaearctic species, in East: Yakutsk, Kamchatka (Meyer 1936;
Townes et al. 1965; Reshchikov 2016) 0... Rh. umbrarum (Holmgren)
Third metasomal tergite with distinct transverse impression, distinctly punctate.
Coxae black. Hind tibia black in apical 0.3 or more with base usually yellowish
brownish. Tergites black or some of them reddish .0..... eee eee ceeeeseeseeeeeeeeeeeeees 2
Median longitudinal carinae of propodeum (Fig. 7) from anterior margin to pos-
terior transverse carina parallel; area petiolaris with strong median longitudinal
carina. Antennal flagellomeres (Fig. 1) and hind femur (Fig. 1) black. — Eastern
Palacarctic part of China ..26...85.0..0.he-nume Rh. nigrus Sheng, Li & Sun, sp. nov.
Median longitudinal carinae of propodeum from anterior margin to posterior
transverse carina evidently convergent or divergent posteriorly; area petiola-
ris without distinct median longitudinal carina. Antennal flagellomeres brown.
Pelitacleheniar bt: LOW DUS MPEG 8 ster ea MRA scat aoe Ae Stiloria tat ad oto cn canted nn Rocce 3
Median longitudinal carinae of propodeum from anterior margin to posterior
transverse carina convergent posteriorly. Scutellum black. Metasomal tergites
almost entirely black. — Transpalaearctic species, in East: Yakutsk (Reshchikov
1.10) 4 CP RI UR A vdes AOE 12 et ne ie bop ae Rh. compactor (Thunberg)
Median longitudinal carinae of propodeum from anterior margin to posterior
transverse carina divergent posteriorly. Scutellum yellow. Metasomal tergites 2
to 4 reddish brown. — Transpalaearctic species, in East: Kamchatka (Reshchikov
010 Cy Laceeavrene ire meer teeore Wake Real or ADA N Rae he STO Rh. leucostomus (Gravenhorst)

Rhinotorus nigrus Sheng, Li & Sun, sp. nov.
http://zoobank.org/CF23EC1 D-BA28-4317-BD9D-5CFBAD9BA84A
Figures 1—9

Etymology. The specific name is derived from the entirely black mesosoma and metasoma.

206 Tao Li et al. / Journal of Hymenoptera Research 77: 203-211 (2020)

Figures 1-9. Rhinotorus nigrus Sheng, Li & Sun, sp. nov. Holotype, female | habitus and host’s cocoon,

lateral view 2 head, anterior view 3 head, lateral view 4 head, dorsal view 5 head, dorsoanterior view 6 mes-

osoma, lateral view 7 propodeum 8 metasoma, dorsal view 9 apical portion of metasoma, lateral view.

207

A new species of genus Rhinotorus Forster

=9. Continued.

Figures

208 Tao Li et al. / Journal of Hymenoptera Research 77: 203-211 (2020)

Material examined. Holotype, female, reared from cocoon of Pristiphora erich-
sonii (Hartig) in Mt. Maoer, Yanji, Jilin Province, China by Tao Li on 24 May 2009.
Paratypes: 3 females, same data as holotype except 25 May—5 June 2009.

Diagnosis. Postocellar line as long as ocular-ocellar line. Area petiolaris of propo-
deum high (Fig. 7) with strong median longitudinal carina and irregular oblique longi-
tudinal wrinkles. First and second tergites (Fig. 8) with distinct subposterior transverse
depressions. First tergite approximately 0.8 x as long as posterior width. Head except
clypeus, mesosoma, metasoma (Fig. 8), and hind leg (Fig. 1) black, except that basal
0.3 of hind tibia brownish and its spurs white.

Description. Body length 6.0—7.0 mm. Fore wing length 6.0-6.5 mm.

Head. Inner orbits parallel. Face (Fig. 2) approximately 1.9 x as wide as long,
slightly evenly convex, lateral portion shagreened, upper-median portion with distinct
punctures; lower-median portion with indistinct punctures; upper margin with me-
dian small tubercle. Clypeus approximately 2.4 x as wide as long, smooth, shiny, with
sparse shallow indistinct punctures, apical median portion convex; median section of
apical margin distinctly depressed. Basal portion of mandible with dense indistinct
punctures; upper tooth sharper and slightly longer than lower tooth. Malar area and
vertex (Fig. 4) shagreened. Malar space approximately 0.5 x as long as basal width
of mandible. Postocellar line approximately same length as ocular-ocellar line. Gena
(Fig. 3) with fine punctures. Frons (Fig. 5) slightly convex medially, with dense fine
punctures. Antenna with 31 flagellomeres; ratio of length from first to fifth flagellom-
eres approximately: 6.5:4.0:3.5:3.5:3.0. Occipital carina reaching hypostomal carina
slightly above base of mandible.

Mesosoma. Along anterior margin of pronotum (Fig. 6) with dense fine punctures;
lateral concavity with weak oblique transverse wrinkles; upper-posterior portion with
dense fine punctures. Mesoscutum, scutellum and postscutellm with fine punctures.
Notauli reaching beyond middle. Scutoscutellar groove almost shiny. Mesopleuron
(Fig. 6) slightly shagreened, upper-median portion with fine transverse wrinkles; spec-
ulum shiny, smooth. Upper end of epicnemial carina approximately reaching to 0.6
distance to subtegular ridge. Metapleuron evenly convex, with dense punctures; lower
posterior portion with oblique wrinkles. Ratio of length of hind tarsomeres from first
to fifth approximately: 10.0:5.0:3.5:2.0:2.5. Wings hyaline. Fore wing with vein Icu-a
slightly distal to M&RS. Postnervulus intercepted at lower 0.4. Hind wing vein 1-cu ap-
proximately 1.5 x as long as cu-a. Propodeum (Fig. 7) with complete strong median lon-
gitudinal and posterior transverse carinae; median longitudinal carinae almost parallel;
between median longitudinal carinae and area petiolaris shiny, remain areae with dense
distinct punctures; area petiolaris with strong median longitudinal carina and irregular
oblique longitudinal wrinkles. Propodeal spiracle small, circular, located at basal 0.25.

Metasoma. First three tergites (Fig. 8) with dense punctures. Subposterior por-
tions of first and second tergites with weak transverse depressions. First tergite ap-
proximately 0.8 x as long as posterior width, with irregular short wrinkles; dorsal me-
dian carina reaching to 0.6 length of first tergite; dorsolateral and ventrolateral carinae

A new species of genus Rhinotorus Forster 209

complete; postpetiole strongly convex; spiracle small, circular, convex, located approxi-
mately at anterior 0.4 of first tergite. Second and third tergites (Fig. 8) approximately
0.5 x as long as posterior width. Fourth and subsequent tergites with relatively sparse
fine punctures. Ovipositor sheath (Fig. 9) approximately 2.3 x as long as its maximum
width, from middle evenly narrowed posteriorly.

Colouration (Fig. 1). Black, except for following: clypeus, maxillary palpi, labial
palpi, malar area, upper-posterior corners of pronotum, tegulae yellowish brown; man-
dible except base and teeth, fore and middle femora, tibiae and tarsi, apexes and bases
of hind femora red brown; ventro-basal portions of hind tibiae brownish yellow; an-
tennae, pterostigma and veins brownish black. Second and third metasomal sternites
black brown.

Male. Unknown.

Distribution. China (Jilin).

Host. Pristiphora erichsonii (Hartig).

Differential diagnosis

The new species is similar to Rh. jussilai Reshchikov, 2016, but can easily be distin-
guished from it by the following combinations of characters: occipital carina reaching
hypostomal carina slightly above base of mandible; area petiolaris of propodeum with
strong median longitudinal carina; hind femur black. Rhinotorus jussilai: occipital ca-
rina reaching hypostomal carina distinctly above base of mandible; area petiolaris of
propodeum without median longitudinal carina; hind femur brownish red.

Discussion

The new species is the only species of R/inotorus recorded in the southeastern part of the
Eastern Palearctic Region. The genus is not recorded in this part of Russia, in Korea and
Japan. Nevertheless in the collections from the boreal and oriental part of China there
are unidentified species of this genus. R/inotorus need in further taxonomical research.

Acknowledgements

The authors are deeply grateful to Drs Gavin R. Broad (NHMUK) and Dmitry R.
Kasparyan (ZISP) for their help in the study on the genus and reviewing the manu-
script. This research was supported by the National Natural Science Foundation of
China (NSFC, No. 31110103062, No. 31501887) and by key project of Science-
technology basic condition platform from The Ministry of Science and Technology of
the People’s Republic of China (Grant No. 2005DKA21402).

210 Tao Li et al. / Journal of Hymenoptera Research 77: 203-211 (2020)

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