Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 June 2022 | 14(6): 21296–21301
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
https://doi.org/10.11609/jott.7902.14.6.21296-21301
#7902 | Received 28 February 2022 | Final
received 07 April 2022 | Finally accepted 15 May 2022
Authentic report of the emesine bug Gardena melinarthrum
Dohrn, 1860 (Hemiptera: Heteroptera:
Reduviidae) from India
Sangamesh R. Hiremath
1, Santana Saikia 2 & Hemant V. Ghate
3
1 Department of Agriculture, Karunya Institute of Technology and Sciences, Karunya Nagar, Coimbatore, Tamil Nadu 641114, India.
2 Department of Zoology, Cotton
University, Panbazar, Guwahati, Assam 781001, India.
3 Post Graduate Research Centre,
Department of Zoology, Modern College of Arts, Science & Commerce (Autonomus), Shivajinagar, Pune, Maharashtra 411005, India.
1 sangu3711@gmail.com, 2 santanasaikia7@gmail.com,
3 hemantghate@gmail.com (corresponding author)
Editor: Anonymity
requested. Date of publication:
26 June 2022 (online & print)
Citation: Hiremath,
S.R., S. Saikia & H.V. Ghate
(2022). Authentic report of the emesine bug Gardena melinarthrum
Dohrn, 1860 (Hemiptera: Heteroptera:
Reduviidae) from India. Journal of Threatened Taxa 14(6): 21296–21301. https://doi.org/10.11609/jott.7902.14.6.21296-21301
Copyright: © Hiremath
et al. 2022. Creative Commons Attribution
4.0 International License. JoTT allows unrestricted use, reproduction, and
distribution of this article in any medium by providing adequate credit to the
author(s) and the source of publication.
Funding: Self-funded.
Competing interests: The authors
declare no competing interests.
Acknowledgements: Ms. Santana Saikia
thanks Dr. Anjana Singha Naorem for guidance. Hemant Ghate is
indebted to Dr. Dávid Rédei
(National Chung Hsing University, Taiwan) for
literature and continuous support and to the authorities of Modern College for
facilities and encouragement. We thank Ms. Sayali Sheth for the preparation of the Images.
Abstract: An emesine
bug, Gardena melinarthrum Dohrn,
1860, is reported from two areas in India—Kerala and Assam. Both, macropterous
and apterous forms are found in India. This is the
first illustrated report of this assassin bug from India.
Keywords: Assam, assassin bug, Emesinae, Emesini, Kerala,
species distribution.
Two macropterous males collected
from Kerala and one apterous female of thread-legged
bug (Emesinae), collected from Assam (Guwahati), were
identified as Gardena melinarthrum Dohrn, 1860 based on the identification keys in Wygodzinsky (1966). Gardena melinarthrum
is the type species of the genus Gardena Dohrn,
1860 by monotypy (Capriles
1990). Wygodzinsky (1966) provided the taxonomic
account with numerous line drawings of the diagnostic characters, along with
information on the distribution of the species. Capriles
(1990) also listed this species and its synonyms.
Dohrn (1860) described Gardena melinarthrum from an apterous
specimen collected in Ceylon (=Sri Lanka). McAtee & Malloch (1926) reported
the species from the Philippines by describing a new form as Gardena melinarthrum var. femoralis
McAtee & Malloch, 1926 and simultaneously also synonymized Dohrn’s another species, Gardena semperi
Dohrn, 1863 as a winged male of G. melinarthrum. Wygodzinsky
(1966) illustrated brachypterous form known from other localities (e.g.,
Taiwan, Philippines, Java, Australia) and synonymized G. m. femoralis with G. melinarthrum.
Ishikawa (2005) provided a brief redescription,
supplemented with photographs of the species (including macropterous form, from
Japan), along with illustrations of diagnostic characters, distribution records
and synonyms; according to this paper, G. melinarthrum
is distributed in Japan, Taiwan, China, Sri Lanka, the Philippines, Indonesia,
Malaysia, and Australia. Recently, Rédei & Tsai
(2010) have also provided information on diagnosis and distribution of this
species. None of the above cited papers mention India as a locality for this
species. Though original descriptions of the species are available (Dohrn 1860), the whereabouts of the type material collected
from Sri Lanka remain unknown, as per Wygodzinsky
(1966).
Wygodzinsky (1966) provided a detailed
description of the genus Gardena as well as of the tribe Emesini to which it belongs; he further divided this genus into four species
groups, the melinarthrum, brevicollis,
longimana, and pipara
groups, based on morphology of fore legs (especially the extent of
spineless portion of fore femur) and the characters of male genitalia. Gardena
melinarthrum obviously belongs to the
nominotypical group. Members of the melinarthrum
group show a length variation from 18.5 mm to 25.0 mm (Wygodzinsky
1966).
Ambrose (2006) published a
checklist of Reduviidae of India but did not include
this species; subsequently, Mukherjee & Saha
(2017) published a paper claiming that they were presenting the first record of
G. melinarthrum from West Bengal, India.
However, Mukherjee & Saha (2017) mentioned the
size of their apterous specimens to be: male 10 mm and female 15.37
mm. Based on the body size alone it appears that the specimens reported by
Mukherjee & Saha (2017) belong to another
species. In addition, the fore tibia in G. melinarthrum
is less than half the length of fore femur, while, Mukherjee & Saha’s image (their Fig. 3) shows a much longer fore tibia
(the lengths provided by the authors are: fore femur 2.80 mm and fore tibia
1.68 mm (implying that the tibia is longer than half length of femur); in
addition, the first long spine of posteroventral
series of fore femur also seems closer to the base of femur (unlike what is
observed in true G. melinarthrum). In any
case, male genitalia of the specimen reported by Mukherjee & Saha (2017) must be studied to resolve the identity issue;
hence, till such a time the previous record of G. melinarthrum
from West Bengal, India must be considered doubtful. Thus, it is imperative to
state that there is no reliable previous record of G. melinarthrum from India, although the finding of a
Sri Lankan species in India is always likely, as mentioned earlier (Sarode et al. 2018).
In this work we are presenting
morphological details along with the illustrations of macropterous male (based
on two specimens), and one apterous form. Since
diagnostic characters of the genus as well this species, along with
illustrations are already provided by the earlier authors cited above, we are
only giving photographic illustrations and relevant characters as a brief redescription here.
Reduviidae, Emesinae,
Emesini.
Gardena Dohrn,
1860
Gardena melinarthrum Dohrn,
1860, p. 214.
Gardena semperi Dohrn,
1863, p. 64
Gardena melinarthrum var. femoralis
McAtee & Malloch, 1925, p. 136.
Winged form from Kerala:
Colouration and vestiture:
Overall colour reddish brown in dorsal aspect, posterior lobe of
pronotum and distal half of abdomen darker (Image 1A,B; Image 2A). Head dark
brown, slightly darker ventrally and covered by short, grey adpressed
setae all over, a distinct shining ‘V’ mark in front of transverse sulcus is
devoid of setae; all antennal segments dark brown, III and IV antennomeres
appearing pale because of dense grey setae. First two antennomeres with long,
erect but sparsely distributed grey setae. Eyes black; labium pale brown (Image
2B,C). Overall legs brown; fore coxae slightly darker than fore femora. In fore
femora spiniform processes of postero-ventral
series with pale bases and black spines while antero-ventral series consists of
thin black setae. Mid and hind femora brown but blackish-brown sub apically,
apex cream. Mid and hind tibiae brown but with basal cream area followed by
dark brown area. Tarsal segments dark brown and hairy. Both mid and hind femora
as well as tibia covered with fine, greyish microchaetae
with only a few macrochaetae. Fore and hind wings pale brown; prosternum pale
brown, meso and metasternum
dark brown to black (Image 3D; Image 4 A,B). Mid and hind coxae and trochanters
dark brown, shining due to sparse setae. Meso and
meta sternum are dull because of dense cover of grey setae. Prosternum also has
moderately dense cover of very fine setae, hence there is mild shining (Image
3D). Fore legs more setose
than mid and hind legs.
Dorsally, abdomen dark brown
along entire length, all abdominal tergites finely sculptured, with fine setae.
Abdomen ventrally dark brown to black, sub shining from fifth segment to pygophore, whereas segments two to four dull; setae on pygophore slightly longer. Spiracles slightly elevated,
their rims shining. Connexivum of moderate width,
pale brown in anterior half and dark brown in posterior half.
Structure: Head elongate, fusiform, anteocular slightly longer than postocular
(without neck). Eyes globular, of moderate size, occupying one third of head
length, lower margin of eye not reaching ventral margin of head; transverse
sulcus more or less straight not passing beyond posterior margin of eye. Anteocular part with distinct, short, median sulcus that
ends at tip of ‘V’ like shining area. Antenniferrous
tubercles situated nearly in middle of anteocular
area. Clypeus and mandibular plates slightly sloping. Labium bent between
visible segments I and II, visible segment I very short, visible segment III
longest. Postocular part of head distinctly narrowed
in to neck (Image 2B,C; Image 4A).
Thorax with long pronotum;
anterior lobe of pronotum much longer than posterior lobe and distinctly
narrowed posteriorly, with a median shallow longitudinal depression, its
surface sparsely granular (Image 1B, Image 2A; Image 3A); posterior lobe
situated at an angle and about twice as wide as middle of anterior lobe,
distinctly rugulose, sub shining, with humeral angles
slightly elevated and button-like (Image 3B). Scutellum and metanotum
without spines. Prosternum with its posterior margin round. Mesosternum
rectangular, with a slight depression in distal part. Metasternum
narrower than mesosternum, with an indistinct carina
in between coxae (Image 3D; Image 4B).
Fore and hind wings short, reaching only posterior border of fourth
abdominal segment (Image 1). Both wings narrow and elongate; forewing with
typical venation (Image 3C).
Fore legs extremely slender,
coxae more than half as long as femur, while tibia less than half as long as
femur (Image 4C). Femur with postero-ventral series of spines that begins at about one
third length of femur from base, first femoral spiniform
process about 0.27 mm long (including basal tubercle) and its distance from
base of femur 2.75 mm (i.e., the first spine is situated at about 10 times the
length of the first spiniform process itself) (Image
5A). There are 12 long spiniform processes each with
pale base and black spine. Extreme apical region there with only small black
denticles; antero-ventral series composed of very fine setae without any
conspicuous base. Fore tibia with long setae underneath, interspersed with
short black and blunt denticles (Image 5B). Hind femora passing tip of abdomen
(see Image 1A).
Abdomen narrow, parallel sided; connexivum narrow. Seventh tergite narrowed posteriorly,
tongue shaped, set at an angle from body and nearly covering pygophore from dorsal side; eighth sternite
partly visible laterally (Image 5C). Pygophore
(detached) cup like, laterally slightly compressed, with distinct
posterosuperior spine and two moderately broad parameres,
visible laterally on each side (Image 6A,B). Parameres
as in Image 6E. Phallus symmetrical, with short but stout articulatory
apparatus, basal plate struts fused into a sclerite. Phallotheca
with moderately sclerotized areas ventrolaterally
(Image 6C); endosoma with two elongate processes
bearing numerous spiny projections (Image 6D).
Material examined: Two winged males from Kerala and
one apterous female from Guwahati, Assam. Preserved
at Modern College at present.
Measurements (in mm): Males from Kerala (leg. S. Hiremath, 10 May 2018, loc. Vellayani)
(n = 2): total body length 24.0/23.0. Total length of head 1.75/1.75, length of
anteocular part 0.50/0.45, of postocular
part 0.50/0.50, eye diameter 0.37/0.37. Antenna: length of segment I 14.0/14.0,
of segment II 11.5/11.4, of segment III 0.50/0.50, of segment IV 2.70/NA.
Labium: Length of visible segment I 0.18/0.20, of visible segment II 0.56/0.55,
of visible segment III 1.1/1.0. Length of anterior lobe of pronotum 3.13/3.15,
of posterior lobe 2.0/2.0. Length of fore coxa 4.5/4.5, of fore femur 7.0/6.95,
of fore tibia 3.4/3.20, of fore tarsus 0.60/0.50; of mid coxa 0.60/0.60, of mid
femur 15.0/15.0, of mid tibia 21.0/20.0, of mid tarsus with claw 0.50/0.50; of
hind coxa 0.60 /0.58, hind femur 25.0/- hind tibia -/-, hind tarsus with claw
-/-. Forewing 10.0/10.0.
Apterous female: The apterous
female from Assam (leg. S. Saikia, Morigaon District, 17 March 2020) is 25 mm in length. Other
measurements are quite comparable to that of macropterous male given above, as
seen from the Image 7A. The specimen was damaged in transit so genitalia
preparation was not possible and so those photographs are not included. Close
up of anterior half (Image 7B) again shows elongate head, bent labium and
slender fore legs. Note the distance of first femoral spiniform
process from the base which is a diagnostic character.
General morphology, except for
thoracic region, is similar to winged form; pronotum is longer than meso and meta notum put together; posterior lobe of
pronotum very short, not covering mesonotum. The fore
legs are very slender, the femoral posteroventral
series of spiniform setae starts away from the base
(at one third length) of the femur itself, fore tibia are slightly less than
one-half length of fore femur. Fore femur has preapical pale spot (mentioned in
var. femoralis by McAtee & Malloch 1926),
which is absent in winged form.
Discussion
Gardena melinarthrum is evidently a widely
distributed species. Wygodzinsky (1966) gives
distribution as “Oriental and Australian regions, from Ceylon (Sri Lanka; type
locality) to Formosa (Taiwan) and Australia”. Its presence in India is
therefore not surprising, even then, it has not been authentically documented
before, with a series of illustrations of the diagnostic characters, as we have
done here. It has already been pointed out that the report of this species by
Mukherjee & Saha (2017) is likely to be a
misidentification; it is clear from the measurements given by them, as well as
the image that shows posteroventral series of spines
beginning before one third length of the femur itself (i.e., the first process
is closer to the base than is known for G. melinarthrum).
These aspects were previously discussed while reporting Gardena brevicollis Stål, 1871 from
India (Sarode et al. 2018). The apterous
form which we have from Assam is about 25 mm and shows all the diagnostic
characters of G. melinarthrum. It is
interesting, at this juncture, to note that this species has not been reported
from Sri Lanka in more than 150 years, i.e., since its original description by Dohrn (Ranasinghe & Ghate
2022).
Wygodzinsky (1966) illustrated diagnostic
features of this species, however, a redescription
was not provided. Ishikawa (2005) presented an excellent comparative account of
five species of Gardena that occur in Japan, two of those being new
species; he also included diagnostic characters and details of the male and
female genitalia and revised the key to the Japanese species of Gardena
(the key includes G. melinarthrum, G. muscicapa (Bergroth, 1906)
and G. brevicollis, that occur in India).
Ambrose (2006) had listed only Gardena
muscicapa to be present in India; with the
present report, and the already reported G. brevicollis
(Sarode et al. 2018), the number of Gardena
species known from India becomes three.
Much remains to be done about the
Indian Emesinae and more thorough surveys need be
conducted to know about the distribution and biology of the existing species
and to check for possibilities of new species or new records.
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