Journal of Threatened Taxa |
www.threatenedtaxa.org | 26 March 2020 | 12(4): 15499–15502
ISSN 0974-7907 (Online) | ISSN 0974-7893
(Print)
doi: https://doi.org/10.11609/jott.5367.12.4.15499-15502
#5367 | Received 29 August 2019 | Final
received 08 February 2020 | Finally accepted 20 February 2020
Description of a new subspecies
of the genus Microcerotermes Silvestri, 1901 (Amitermitinae: Termitidae: Isoptera) and the first record of another termite species
from Meghalaya, India
Khirod Sankar
Das 1 & Sudipta Choudhury 2
1,2 Department
of Zoology, North Eastern Hill University, Shillong,
Meghalaya 973022, India.
1 khirodsankar@gmail.com,
2 sudiptapinku@gmail.com (corresponding author)
ZooBank: urn:lsid:zoobank.org:pub:AAF00A11-DE35-4663-9572-729AE91F19C0
Editor: R. Sundararaj, Institute of Wood Science & Technology,
Bengaluru, India. Date
of publication: 26 March 2020 (online & print)
Citation: Das, K.S. & S. Choudhury (2020). Description
of a new subspecies of the genus Microcerotermes
Silvestri, 1901 (Amitermitinae: Termitidae:
Isoptera) and the first record of another termite
species from Meghalaya, India. Journal
of Threatened Taxa 12(4): 15499–15502. https://doi.org/10.11609/jott.5367.12.4.154990-15502
Copyright: © Das & Choudhury 2020. 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: UGC-National
Fellowship for SC Students
(NFSC).
Competing interests: The authors declare no competing interests.
Acknowledgements: We would like to thank the head, department of
Zoology, NEHU, Shillong for all the necessary
facilities provided to carry out the research work. We are thankful to UGC for
providing fellowship under NFSC (vide-
F1-17.1/2017-18/RGNF-2017-18-SC-ASS-35335) to the first author. We are also
thankful to Rodeson Thangkhiew
and Graham Rani, Research scholars, department of Zoology, NEHU, for helping
with the sample collection.
Abbreviations: HL—Head length; HLM—Head length with mandible; HW—Head
width; LL—Labrum length; LW—Labrum
width; ML—Mandible length; PL—Pronotum length; PW—Pronotum width; PoL—Postmentum length; PoW—Postmentum width; PoWW—Postmentum width at waist;
Post L—Postclypeus length; Post W—Postclypeus
width; TBL—Total body length.
Microcerotermes is a cosmotropical
genus occurring in all the zoogeographical regions except Nearctic region with
around 148 living species (Chhotani 1997; Krishna et
al. 2013). In the Oriental region, this
genus is widely distributed in almost all the countries of the region and
equally well distributed in the Ethiopian region too (Chhotani
1997). According to Chhotani
(1997), the oriental region comprises 42 species under the genus Microcerotermes with 29 species from the Indian
region. The northeastern part of India,
which harbors 76 species of termites, comprises four species of the genus Microcerotermes out of which one is endemic
to the region (Bose 1999). But, from
Meghalaya, one of the states of northeastern India, there was no earlier report
of the genus. On the other hand, the
genus Reticulitermes is palaearctic in distribution which is extended in the colder
parts of Indian region with around 60 species in total. The Indian region comprises of five species
with two species reported from the state of Meghalaya (Bose 1999).
In
our recent study on the termite fauna of Megyalaya,
we identified the genus Microcerotermes for
the first time with the description of a new subspecies due to its
characteristic differences from the nominate species. The subterranean termite species Reticulitermes chinensis
is also a new record from the state and the morphometrics of which is also
revised here.
The
specimens studied were collected from different parts of Meghalaya and were
preserved in 80% alcohol. Measurements
of the specimens were done using Leica stereo zoom microscope S8AP0 and the
identification was done based on available literature and taxonomic keys (Roonwal & Chhotani 1989; Chhotani 1997). All
the samples studied are deposited in the national repository of the Zoological
Survey of India, North Eastern Regional Centre, Shillong,
Meghalaya.
Family:
Termitidae
Subfamily:
Amitermitinae
Microcerotermes labioangulatus
wahkdaitensis
ssp.
nov.
(Image
1 A–E)
urn:lsid:zoobank.org:act:F63C9179-D913-4F96-9F81-A434C0027635
Type
materials studied
Holotype:
Voucher No. IV/ISOP/ERS/4424, one ex. soldier, 22.ii.2019, Wahkdait
area, East Khasi Hills, Meghalaya, India, 25.2080N & 91.9900E,
388m, coll. Khirod Sankar Das & party.
Paratype:
Voucher No. IV/ISOP/ERS/4425, one ex. soldier and 24 exs.
workers, same information as in Holotype.
Other
materials studied: Voucher No. IV/ISOP/ERS/4426, 11 exs.
soldiers and three exs. workers, 24.iv.2019, Wahkdait area, East Khasi Hills, Meghalaya, India, 25.2080N
& 91.9890E, 388m, coll. Khirod Sankar Das & party.
Description
Soldier
(Image 1, A–C): Head-capsule yellowish-brown to deep brown; antennae yellowish-brown;
mandibles dark reddish-brown; body straw in color. Head sparsely and body moderately hairy. Head-capsule long, rectangular, sides almost
parallel. Antennae with 13 segments;
segment 3 shortest, 4 longer than 5 or sub equal to 5. Labrum pentagonal; antero-lateral corners
angulated and anterior margin somewhat pointed at middle; broader than long. Mandibles strongly curved like a scathye and apically pointed and incurved; mandible length
less than the half of the head-length; inner margin coarsely serrated in basal
half. Postmentum
club-shaped, a little narrowed at waist behind middle. Pronotum saddle-shaped.
Worker
(Image 1, D–E): Head-capsule and antennae yellowish; body paler than head. Head moderately and body densely hairy. Head-capsule subsquarish. Fontanelle indistinct. Antennae 13 segmented; segment 3 shortest, 5
longer than 4 or sub equal to 4. Postclypeus swollen, hairy; length a little more than half
of width. Pronotum saddle-shaped;
anterior margin with a distinct notch, posterior margin weakly emarginated.
Diagnosis:
The
morphometrics (Table 1) of this new subspecies is very close to that of the
species Microcerotermes labioangulatus
but shows striking differences in the taxonomic characters with high importance
(Chhotani 1997).
In this subspecies, the length of the mandible is less than the half of
the head length (without mandible) whereas in case of M. labioangulatus
the length of mandibles is more than the half of the head length. The mandible length and the head length
(without mandible) index is also less than that of the M. labioangulatus.
On the other hand, the antennal segments of soldiers have shown slight
differences as segment two is slightly longer than segment four and segment
four is subequal to or slightly longer than segment five whereas in M. labioangulatus, segment four is longer than segment
five. In case of workers too, segment
five is longer than or subequal to four whereas in M. labioangulatus,
segment four is longer than five. The
total body length of the smaller workers also found to be less than the lower
range of M. labioangulatus. Further, this subspecies also showed some
similarities in the structure of labrum and head with the soldiers of M. pakistanicus which is also reported from India. But, can be separated clearly based on the
differences of head length, mandible length, mandible and head length index, postmentum length, pronotum length and width of soldiers
and the total body length, pronotum length and width of the workers of both the
species (Chhotani 1997).
Etymology: This subspecies is named
after its type locality which is Wahkdait area near Pynursla, East Khasi Hills, Meghalaya.
Distribution: Wahkdait,
East Khasi Hills, Meghalaya, India.
Family:
Rhinotermitidae
Subfamily:
Heterotermitinae
Reticulitermes chinensis Snyder, 1923
Materials
examined-
Voucher No. IV/ISOP/ERS/4427, 23 exs. soldiers and 20
exs. workers, 25.vii.2019, NEHU Campus, Shillong, Meghalaya, India, 25.6130N &
91.9000E, 1,413m, coll. Khirod Sankar Das.
Description
Soldier
(Image 2, A–B): TBL 5.90-7.10 mm; head-capsule sub rectangular, longer than wide, length
1.83–2.27; HW 1.08–1.32 mm. Antennae
with 16, 17 or 18 segmented; segment 3 shortest in 16 and 17 segmented one and
segment 4 shortest in 18 segmented one.
Labrum oval, longer than broad, usually broadest near the base; sides
convex with hyaline margin and converging into thin and sharply pointed tip
having two long bristles. ML 0.95–1.22
mm; left mandible with 3–4 crenulations arid a basal projection. PoL 1.30–1.50; PoW 0.43–0.52; PoWW 0.12–0.15
mm. Pronotum flat, narrower than head;
length 0.50–0.55, width 0.82–0.95.
Workers:
Dimorphic: Worker minor: TBL 3.50–4.00 mm, HL 1.05–1.07, HW 1.17–1.22 mm. Antennae 15 segmented, segment 2 longer than
3, 4 shortest. Mandibles typically Reticulitermes-type. Pronotum flat, length 0.42–0.50 mm, width
0.77–0.85 mm (Adapted from Roonwal & Chhotani 1989).
Worker
major (Image 2, C–E): TBL 4.80–5.15 mm, HL 1.00–1.30, HW 1.07–1.45 mm. Antennae 16–18 segmented, segment 4 is
shortest in 16 and 18 segmented one and segment 3 is shortest in 17 segmented
one. Pronotum flat, length 0.42–0.50 mm and width 0.77–0.85 mm.
Redescription: The morphometrics of R. chinensis from the study area show variation in
comparison to the descriptions in available literature (Roonwal
& Chhotani 1989).
Variation among the individuals of R. chinensis
may be because of their inclined nature toward variation or because of the
climatic condition of the study area which is usually colder (Average maximum
temperature 120C in Winter and 250C in Summer). The HLM, HW/HL, and ML/HL index of the
soldier castes are provided here based on this study. Here, the upper ranges of the PL, PoL, and PoWW have been found
slightly more than the ranges reported earlier.
In case of the workers, the TBL, HL, HW were found to be greatly varied
than the range in available literature.
The antennae of the worker individuals also vary significantly which
were found to be 16, 17 or 18 segmented.
In case of 16 and 18 segmented one, segment 4 is shortest and in 17
segmented one, segment 3 is shortest. We
did not get workers with 15 segmented antenna from the study area. Based on the morphometrics of R. chinensis from the samples studied by us and the
descriptions by Roonwal & Chhotani
(1989), we designate the workers as worker major and worker minor and revise
the morphometrics for the species through this communication (Table 2).
Distribution:
China and
India (Arunachal Pradesh, Assam, and Meghalaya).
The
description of the new subspecies of the genus Microcerotermes
forms the first report of the genus from Meghalaya, India, which revealed
the probability of more new discoveries of termite species from the state. Furthermore, the revised morphometrics of Reticulitermes chinensis
will definitely help future workers in correct identification of the species
from the study area.
Table 1. Morphometrics (in mm) of soldiers (n=13) and
workers (n=27) of Microcerotermes labioangulatus wahkdaitensis ssp.
nov.
Characters |
Soldiers |
Workers |
|
Holotype |
Size ranges |
Size ranges |
|
TBL |
5.6 |
5.00–5.65 |
3.80–5.10 |
HLM |
2.55 |
2.45–2.75 |
– |
HL |
1.75 |
1.75--–1.85 |
0.85–1.05 |
HW |
1.00 |
1.00–1.10 |
0.88–1.13 |
HW/HL |
0.57 |
0.57–0.60 |
– |
ML |
0.80 |
0.75–0.95 |
– |
ML/HL |
0.48 |
0.40–0.54 |
– |
PL |
0.43 |
0.40–0.45 |
0.25–0.38 |
PW |
0.73 |
0.73 |
0.50–0.68 |
PoL |
1.00 |
1.00–1.10 |
– |
PoW |
0.33 |
0.30–0.35 |
– |
PoWW |
0.18 |
0.18 |
– |
LL |
0.25 |
0.18–0.25 |
– |
LW |
0.43 |
0.35–0.43 |
– |
Post L |
– |
– |
0.28–0.33 |
Post W |
– |
– |
0.43–0.55 |
Table 2. Revised morphometrics (in mm) of Reticulitermes chinensis
Snyder, 1923.
Reticulitermes chinensis Snyder, 1923 |
|||
Characters |
Soldiers (n=23) |
Workers minor |
Workers major (n=20) |
TBL |
5.90–6.70 |
3.50–4.00 |
4. 80–5.15 |
HLM |
2.85–3.15 |
– |
– |
HL |
1.90–2.15 |
1.05–1.07 |
1.00–1.30 |
HW |
1.10–1.20 |
1.17–1.22 |
1.07–1.45 |
HW/ HL |
0.52–0.60 |
– |
– |
ML |
0.95–1.05 |
– |
– |
ML/ HL |
0.47–0.51 |
– |
– |
PL |
0.55–0.60 |
0.42–0.50 |
0.42–0.45 |
PW |
0.90–0.95 |
0.77–0.85 |
0.77–0.85 |
PoL |
1.45–1.60 |
– |
– |
PoW |
0.45–0.50 |
– |
– |
PoWW |
0.18 |
– |
– |
Antennal segments |
16 or 17 or 18 segmented. In 16 and 17, 3rd or 4th is
shortest. In 18 segmented, 4th is shortest. |
15 segmented. 4th segment is shortest. |
16 or 17 or 18 segmented.In
16 and 18 Segmented, 4th is shortest. In 17 segmented, 3rd
segment is shortest. |
References
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