The first record of the spider genus Coreodrassus Paik 1984 (Araneae: Gnaphosidae) for Mongolia with description of a new species

Abstract

A new species of ground spider, Coreodrassus boldgivi sp. nov., is diagnosed, illustrated and described based on a male specimen. The genus Coreodrassus itself is also recorded for Mongolia for the first time. The holotype was found in a woodland habitat within the semi-desert zone in Dornogovi Aimag, southeastern Mongolia. The new species is related to C. lancearius (Simon 1893) and differs from it by the shape of the male palp.

Full text

Introduction
The family Gnaphosidae Banks 1892 is an exceptionally
large group, comprising 2442 species placed in 146 genera
(World Spider Catalog 2022). Currently, more than 85 spe-
cies of ground spiders from 15 genera have been recorded
in Mongolia (World Spider Catalog 2022). Gnaphosids are
distributed throughout the most of the drylands on earth, but
their diversity is higher within temperate zone (Zhang &
Zhu 2008). Among gnaphosids, Coreodrassus Paik 1984 is
a small, Central and East Asian genus, currently comprising
only four described species (World Spider Catalog 2022).
The genus was rst established in 1984 by a Korean arach-
nologist Kap Yong Paik (1984) and was then considered to
be monotypic. However, two additional species were de-
scribed in subsequent years from Kazakhstan (Ponomarev &
Tsvetkov 2006) and China (Zhang & Zhu 2008), respective-
ly. Finally in 2019, the species Drassus interlisus O. Pick-
ard-Cambridge 1885 was transferred to Coreodrassus by
Marusik and Omelko (2019). No species of Coreodrassus
has been known from Mongolia until now. While examin-
ing spider materials recently collected by the senior author
from Southeastern Mongolia, we found a male specimen of
this genus that belonged to an undescribed species. Herein,
a detailed description and diagnosis of this new species are
provided, representing the first record of the genus from
Mongolia.
Material and methods
The collected specimen was stored in a vial with 70 per-
cent ethanol. A dissected palp was stored in a separate vial
with labels. The holotype was examined and deposited in
the Laboratory of Ecology and Evolutionary Synthesis, Na-
tional University of Mongolia, Ulaanbaatar, Mongolia. The
specimen was photographed using Leica DFC450 C micro-
scope camera with c-mount interface with a 5 Megapixel
CCD sensor. Digital images were montaged using Leica
Application Suite V4. To make the internal structure of the
palp visible for examination, we cleared it in lactic acid,
which can dissolve soft tissues without damaging the harder,
chitinous parts. The images were taken after the palp had
been fully dried. Eye sizes were measured as the maximum
diameter in dorsal view. Abbreviations: ALE, anterior lateral
eyes; AME, anterior median eyes; d, dorsal; Fe, femur; Mt,
metatarsus; p, prolateral; Pa, patella; PLE, posterior lateral
eyes; PME, posterior median eyes; r, retrolateral; Ti, tibia;
v, ventral; NUM, National University of Mongolia. All mea-
surements are given in millimeters.
Taxonomy
Coreodrassus boldgivi sp. nov.
Figs. 1–2
Type material. Holotype ♂ (NUM), Mongolia, Dor-
nogovi Aimag, Khövsgöl Sum, N 43°35’52.69”, E
109°15’36.71”, September 18, 2022, N. Jugdernamjil & J.
Ochirkhuyag.
Etymology. The specific epithet is an eponym in honor
of Professor Bazartseren Boldgiv (Ulaanbaatar) for his sig-
nificant contributions and dedication for the promotion of
natural sciences in Mongolia.
Diagnosis. The new species is similar to Coreodrassus
The rst record of the spider genus Coreodrassus Paik 1984 (Araneae: Gnaphosidae)
for Mongolia with description of a new species
Ochirkhuyag Jargalsaikhan1, 2 *, Alexander A. Fomichev3, 4 & Jugdernamjil Nergui1
1Wildlife Science Conservation Center of Mongolia, Ulaanbaatar, Mongolia
2Department of Biology, School of Arts and Science, National University of Mongolia, Ulaanbaatar, Mongolia
E-mail: ochirkhuyag0504@gmail.com
3Altai State University Lenina Pr., 61, Barnaul, RF-656049, Russia.
4Tomsk State University, Lenina Pr., 36, Tomsk, RF-634050, Russia.
*Correponding author
Abstract — A new species of ground spider, Coreodrassus boldgivi sp. nov., is diagnosed, illustrated and de-
scribed based on a male specimen. The genus Coreodrassus itself is also recorded for Mongolia for the rst
time. The holotype was found in a woodland habitat within the semi-desert zone in Dornogovi Aimag, south-
eastern Mongolia. The new species is related to C. lancearius (Simon 1893) and diers from it by the shape of
the male palp.
Key words ― Aranei, biodiversity, Central Asia, Gobi Desert, ground spiders
Acta Arachnologica, 72 (1): 59–62, June 20, 2023

O. Jargalsaikhan, A. A. Fomichev & J. Nergui
lancearius (Simon 1893), which is widespread in Eastern
Palaearctic. Both species have a pointed and unforked ret-
rolateral patellar apophysis (RPA). The male of the new
species can be distinguished from that of C. lancearius by
dorsal branch of retolateral tibial apophysis (dRTA) not
crossing with a ventral branch of retrolateral tibial apoph-
ysis (vRTA) from any side of view (vs. crossing dorsal and
ventral branches) and by the embolus (E) with well-devel-
oped triangular ridge (vs. smooth) (cf. Fig. 2 and gs. 4–6 in
Zhang & Zhu 2008).
Description. Male. Body 8.17 long. Carapace: 4.19 long,
2.90 wide, 1.26 height. Abdomen: 4.41 long, 2.68 wide. Eye
sizes and interdistances: AME 0.25, ALE 0.19, PME 0.22,
PLE 0.17, AME–AME 0.18, AME–ALE 0.01, PME–PME
0.02, PME–PLE 2.23, ALE–PLE 0.12. Clypeus height 0.17.
Length of chelicera 1.89. Leg spination: I: Fe d1, p1; II: Fe
Table 1. Leg measurements.
femur patella tibia metatarsus tarsus total
I3.03 1.51 2.54 1.80 1.31 10.19
II 2.58 1.31 2.02 1.80 1.31 6.44
Ⅲ2.31 1.01 1.40 1.94 1.20 7.86
IV 2.80 1.41 2.34 2.85 1.46 10.87
Fig. 1. Habitus (A–C) and cephalic part (D–E) of Coreodrassus boldgivi sp. nov. A, E – dorsal; B – ventral; C – lateral; D – anterior. Scale bars:
1mm.
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Acta Arachnologica, 72 (1), June 2023 ⒸArachnological Society of Japan

First record of Coreodrassus for Mongolia
Fig. 2. Male palp (A–D), bulb (E–H), cymbium (I–J) and palpal patella and tibia (K–L) of Coreodrassus boldgivi sp. nov. A, I – ventral; B, E, J –
dorsal; C, H, K – retrolateral, D, F – prolateral; G – anterior. Abbreviations: C – conductor, CM – cymbium, dRTA – dorsal branch of retrolateral
tibial apophysis, vRTA – ventral branch of retrolateral tibial apophysis, E – embolus, MA – median apophysis, RPA – retrolateral patellar apohy-
sis, ST – subtegulum, T – tegulum. Scale bars: A–D = 0.5 mm; E–L = 0.3 mm.
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O. Jargalsaikhan, A. A. Fomichev & J. Nergui
d2, r1; Mt v2; III: Fe d2, p1, r1; Pa p1, r1; Ti d2, p2, r2, v6;
Mt d2, p4, r4, v6; IV: Fe d3; Pa p1; Ti p3, r2, v6; Mt d6, p3,
r4, v7. Leg formula: 4132.
The male palp is shown in Fig. 2. Patella swollen, twice
longer than tibia. Retrolateral patellar apophysis (RPA) is
unforked, with its distal part bent at an angle of 90 degrees.
The dorsal branch of retrolateral tibial apophysis (dRTA) di-
rected dorso-posterioriarly. The ventral branch of retrolateral
tibial apophysis (vRTA) directed anteriorly. Cymbium 3.7
times longer than tibia, bearing triangular retrolateral pro-
trusion. Subtegulum (ST) shifted prolaterally. Tegulum (T)
convex. Sperm duct (SD) poorly visible. Median apophysis
(MA) hook shaped, twice shorter than embolus. Conductor
(C) small, translucent. Embolus (E) large, almost straight,
with triangular ridge anteriorly.
Female unknown.
Distribution. Known from the type locality only.
Acknowledgments
We are truly grateful to Otgonbayar Tsend, Khurelsukh Dulmaa,
Ochirkhand Erdenebayar, Bayarmaa Chuluunbat, Tseveenmyadag
Natsagdorj, and Nyambayar Batbayar for their support with sam-
ple collection during eld trips. We would like to thank Dr. Yuri M.
Marusik (Magadan, Russia) for constructive comments and Dr. Ba-
zartseren Boldgiv for proong the English. Ochirkhuyag Jargalsaikhan
was aided by the Taylor Family-Asia Foundation Endowed Chair in
Ecology and Conservation Biology. Moreover, Ochirkhuyag Jargal-
saikhan and Jugdernamjil Nergui were supported by Wildlife Science
and Conservation Center of Mongolia.
References
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Received January 16, 2023 / Accepted April 20, 2023
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Acta Arachnologica, 72 (1), June 2023 ⒸArachnological Society of Japan