Redescription of Dermacentor everestianus Hirst (Acari: Ixodidae), a Parasite of
Mammals in Mountains of China and Nepal with Synonymization of D. abaensis
Teng and D. birulai Olenev
Author(s): Dmitry A. Apanaskevich, Wei Duan, Maria A. Apanaskevich, Natalia A. Filippova, and Jun
Chen
Source: Journal of Parasitology, 100(3):268-278. 2014.
Published By: American Society of Parasitologists
DOI: http://dx.doi.org/10.1645/13-369.1
URL: http://www.bioone.org/doi/full/10.1645/13-369.1
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J. Parasitol., 100(3), 2014, pp. 268–278
Ó American Society of Parasitologists 2014
REDESCRIPTION OF DERMACENTOR EVERESTIANUS HIRST (ACARI: IXODIDAE), A
PARASITE OF MAMMALS IN MOUNTAINS OF CHINA AND NEPAL WITH SYNONYMIZATION
OF D. ABAENSIS TENG AND D. BIRULAI OLENEV
Dmitry A. Apanaskevich, Wei Duan*, Maria A. Apanaskevich, Natalia A. Filippova†, and Jun Chen*
United States National Tick Collection, the James H. Oliver Jr. Institute for Coastal Plain Science, Georgia Southern University, Statesboro, Georgia 304608056. Correspondence should be sent to: [email protected]
ABSTRACT: Examination of extensive Dermacentor Koch, 1844 holdings stored in several major tick collections allowed us to reevaluate the taxonomic content of Dermacentor everestianus Hirst, 1926 and redescribe all of its parasitic stages in detail for the first
time. Examination of the type specimens of Dermacentor abaensis Teng, 1963, a species treated as valid by most workers, and
Dermacentor birulai Olenev, 1927, a species some recent authors considered as valid, led us to the conclusion that they are junior
synonyms of D. everestianus. The relation of D. everestianus with some other species in the genus is questionable and warrants further
studies. From possibly sympatric Dermacentor species, the adults of D. everestianus can be distinguished by the following combination
of characters: intensive ivory colored ornamentation of conscutum and scutum, absence of brown patches on lateral fields of
conscutum in the male, long and narrow dorsal prolongation of spiracular plates, short cornua, short dorsal spur on trochanter I, and
absence of large ventral spur on distal ends of genua and tibiae II–IV. Nymphs of D. everestianus can be distinguished by numerous
setae on alloscutum (.48 pairs), large spiracular plates with their longitudinal diameter exceeding that of sclerotized ring around anal
valves, moderate lateral projections of basis capituli with blunt apices situated slightly posterior to the midlength of basis capituli
dorsally, relatively large auriculae, relatively short, narrowly rounded at apices spurs on coxae I with internal spur being shorter than
external and moderate triangular spur on coxae IV; while larvae can surprisingly easily be distinguished from those of other species
found in the region by greatly elongated posterior portion of scutum where eyes are situated just posterior to the midlength of scutum.
So far, D. everestianus is found only in China and Nepal, where the adults were collected from domestic and wild ungulates while the
immature stages were recorded from lagomorphs and rodents.
The systematics of Palearctic Dermacentor Koch, 1844 species
is still debatable in a number of aspects. Many species remain
insufficiently described and poorly represented in collections. As a
result, identification of adults causes many problems while
identification of the immature stages is often very difficult or
impossible. Three rare and taxonomically controversial Dermacentor species, namely Dermacentor everestianus Hirst, 1926,
Dermacentor birulai Olenev, 1927 and Dermacentor abaensis
Teng, 1963, were described from the Tibet region of China.
Dermacentor everestianus was briefly described from a single
male collected in Tinki Dzong (Tibet, China) (Hirst, 1926).
Schulze (1943) redescribed the male of this species, based on few
specimens from Kamba ba tsi (Tibet, China), and described the
female for the first time. He also provided illustrations of both
sexes for the first time. Arthur (1960) redescribed and illustrated
both sexes of D. everestianus, again based on the holotype male
and a few additional specimens from Rongbuk and Dochin in
Tibet (China). The next redescription of the adults was provided
by Teng (1978) and Teng and Jiang (1991) based on original
material from Tibet. Despite multiple but rather schematic
redescriptions of D. everestianus adults, this species still remained
quite poorly defined. The immature stages remained unknown.
The second species, D. birulai, was described from males and
females collected in Sichuan (China) (Olenev, 1927). This species
was later redescribed and illustrated by Olenev (1929). Arthur
(1960), Teng (1978), Teng and Jiang (1991), and Camicas et al.
(1998) considered this species to be a junior synonym of D.
everestianus. However, Filippova (1997) and Kolonin (2009)
treated D. birulai as a valid species. The immature stages remained
unknown.
Finally the third species, D. abaensis, was described from adults
collected in Maerkang Xian ( ¼ Barkam Xian), Aba Zangzu and
Qiangzu Autonomous Region, Sichuan (China) (Teng, 1963).
Larva and nymph of this species were described later (Jiang, 1984;
Jiang and Li, 1989; Teng and Jiang, 1991). This species was
treated as valid in all recent lists of species and in the literature
(Guglielmone et al., 2010). However, in the NAMRU translation
(T 446) of Teng’s publication Harry Hoogstraal provided a
footnote where he stated that D. abaensis is D. everestianus. This
synonymization was also stated in Robbins and Robbins (2003).
Kolonin (2009) pointed out that D. abaensis resembles D. birulai
very much and possibly should be treated as a junior synonym of
the latter species.
Thus, up to now the situation was as follows: D. everestianus is
a well-accepted species, partially because the specimens of this
species are represented in several world natural history collections
and various independent workers did studies on it; D. birulai is
known only from the type series and it seems that no one critically
re-examined them; D. abaensis is present mostly in Chinese
collections and the existing descriptions are not sufficient to firmly
support its validity.
After examination of the type specimens of all 3 taxa, as well as
of extensive material identified as D. everestianus and D. abaensis
in the United States National Tick Collection (USNTC), the
Institute of Zoology of the Chinese Academy of Science (IZCAS),
the Zoological Institute of the Russian Academy of Sciences
(ZIRAS), and the Natural History Museum (London), we came
to the conclusion that D. birulai and D. abaensis should be treated
as junior synonyms of D. everestianus. The male, female, nymph,
and larva of this species are redescribed in detail here and data on
its geographic distribution and host–parasite relationships are
provided. We hope that this work will stimulate further
investigation of this rare Dermacentor species of the mountainous
regions in Central Asia.
Received 10 August 2013; revised 31 December 2013; accepted 13
January 2014.
* Key Laboratory of Zoological Systematics and Evolution, Institute
of Zoology, Chinese Academy of Sciences, Beijing 100101, P. R.
China.
† Zoological Institute, Russian Academy of Sciences, St Petersburg
199034, Russia.
DOI: 10.1645/13-369.1
268
APANASKEVICH ET AL.—DERMACENTOR EVERESTIANUS
MATERIALS AND METHODS
The material examined is summarized in Table I. Field-collected and
laboratory-reared ticks were available for study. Larvae have been
associated with the adults based on laboratory-reared specimens and
previous description; nymphs were associated with the adults through
previous description and indirect evidence such as hosts, geographic data,
and morphological comparison with all species known in the region. The
specimens that were examined are deposited in the USNTC (Georgia
Southern University, Statesboro, Georgia), the IZCAS (Beijing, China),
the ZIRAS (St. Petersburg, Russia), and the Natural History Museum
(London, U.K.).
The immature stages were mounted on glass slides and examined under
a light microscope (Olympus BX41, Olympus Corporation, Tokyo,
Japan). All stages were also studied by means of a stereoscopic microscope
(Olympus SZX16, Olympus Corporation) and a scanning electron
microscope (JOEL JSM6610LV, JOEL Ltd., Tokyo, Japan). The
nomenclature of the brown patches on the conscutum of the male and
the scutum of the female is that of Filippova (1997) while the
nomenclature of larval setae is that of Clifford and Anastos (1960). Host
nomenclature is that of Wilson and Reeder (2005). Measurements for the
male and female are given in millimeters and those for the various features
of the nymph and larva in micrometers. The measurements are presented
as follows: minimum–maximum (mean 6 standard deviation, n ¼ number
of specimens measured). All illustrations have been drawn by D. A.
Apanaskevich and colored and edited by M. A. Apanaskevich.
Redescription
Dermacentor everestianus Hirst, 1926
(Figs. 1–4)
Male (Figs. 1A, 2A–F, 3A–F): Conscutum (Figs. 1A, 2A–F): narrowly
oval, widest posterior to mid-length; distance from scapular apices to
posterior margin of conscutum 2.55–4.46 (3.75 6 0.35; n ¼ 157),
maximum width 1.67–2.65 (2.25 6 0.20; n ¼ 157), ratio length to width
1.45–1.83 (1.66 6 0.06; n ¼ 157). Coloration: extensive pale ivory-colored
ornamentation covering most of conscutum. Light- to dark-brown
background arranged as follows: 1 pair of narrow patches around eyes
(ocular patches); 6 pairs of narrow patches in festoonal grooves (festoonal
patches); 5 pairs of lateral patches (anteriorly narrow cervical patches in
the cervical grooves, then follow 2 pairs of patches: externally anterior
marginal and internally anterior submarginal, then posterior marginal and
after this posterior submarginal in the paramedian areas), 1 pair of round
patches in the center of conscutum (foveal patches), and 1 central patch in
the posteromedian area (posteromedian patch). Anterior marginal,
anterior submarginal, posterior marginal, posterior submarginal, and
posteromedian patches vary from narrow to elongatedly oval; in rare cases
anterior and posterior marginal patches can be fused; all patches may have
hazy coloration around or sometimes inside the patches; marginal grooves
often also brown, especially in their posterior part; pseudoscutum and
cervical grooves lateral to cervical patches with numerous small irregular
patches giving them often a speckled or hazy appearance; in darker
specimens small patches lateral to cervical patches may form diffuse
paracervical patches; lateral fields without patches. Cervical grooves
shallow; a pair of very shallow central depressions and a second posterior
pair that correspond to paramedian grooves; lateral grooves superficial
but often distinct because of the dark punctations aligning them; 11
distinct festoons; median festoon usually slightly narrower than paramedian festoons. Small to medium-sized brown punctations dense, evenly
distributed over scutum, in many specimens brown coloration surrounds
each punctation. Eyes (Fig. 1A): oval, very slightly convex, at anterior 1/5
of conscutal length. Setae relatively sparse and short. Spiracular plates
(Fig. 3A): positioned on ventral surface in unengorged specimens, suboval,
greatest diameter in anteroposterior plane; perforated portion of dorsal
prolongation long and narrow, tapering to its apex; dorsal prolongation
with narrow, non-perforated portion anteriorly which may have small
ivory-colored spot; perforations small and fairly numerous. Sclerotized
plaques on festoons ventrally extensively ornate. Gnathosoma (Figs. 1A,
3B, C): length from palpal apices to cornual apices dorsally 0.55–0.80
(0.71 6 0.05; n ¼ 157), width of basis capituli 0.36–0.55 (0.45 6 0.03; n ¼
157), ratio length to width 1.43–1.94 (1.57 6 0.08; n ¼ 157). Basis capituli
(Figs. 1A, 3B, C): dorsally subrectangular; posterior margin nearly
straight or slightly concave; length 0.24–0.41 (0.34 6 0.03; n ¼ 157), ratio
269
width to length 1.13–1.60 (1.34 6 0.08; n ¼ 157); cornua broad, relatively
short, equivalent to a proportion of 3.25–13.33 (5.61 6 1.54; n ¼ 157) of
length of basis capituli; basis capituli dorsally with whitish enameling.
Basis capituli ventrally subrectangular; posterior margin convex. Palpi
(Figs. 1A, 3B, C): short, broad; length dorsally (I–III segments) 0.31–0.43
(0.37 6 0.02; n ¼ 157), width 0.19–0.29 (0.24 6 0.02; n ¼ 157), ratio length
to width 1.36–2.12 (1.56 6 0.11; n ¼ 157), length of segments in
descending order: 2, 3, 1, 4; segment I well-developed ventrally; segment II
narrower at base and thereafter widening without clear denticle at
posterior margin dorsally; segment III subrectangular with broadly
rounded apex; segments II and III with whitish enameling on dorsal
surfaces. Hypostome (Fig. 3C): club-shaped; dental formula 3/3. Legs
(Fig. 1A): of medium length, moderately robust; with extensive whitish
enameling mostly on dorsal and lateral aspects. Coxae (Fig. 3D, E): coxa I
with long, triangular, closely spaced internal and external spurs with
tapering or narrowly rounded apices; external spur usually slightly longer
(but may be nearly equal to or slightly shorter) than internal; both spurs of
coxa I directed slightly posterolaterally; coxae II and III each with larger
narrow triangular external spur with tapering apex and smaller broadly
oval internal spur; coxa IV with larger narrow triangular external spur
with tapering apex; coxa IV enlarged, ratio length to width 1.23–2.10 (1.66
6 0.13; n ¼ 145); coxae with or without enameling. Trochanter I (Fig. 3F)
with moderate, broadly triangular dorsal spur with blunt apex. Genu IV
and Tibia IV (Fig. 1A) with 2 rows of short projections ventrally. Genu IV
length 0.65–0.87 (0.76 6 0.06; n ¼ 30), width 0.31–0.49 (0.41 6 0.04; n ¼
30), ratio length to width 1.67–2.11 (1.87 6 0.11; n ¼ 30).
Female (Figs. 1B, 2G–I, 3G–M): Idiosoma of unengorged specimens
(Fig. 1B): narrowly oval, widest slightly posterior to mid-length. Scutum
(Figs. 1B, 2G–I): long, length 1.37–2.12 (1.75 6 0.13; n ¼ 159), width 1.22–
1.77 (1.51 6 0.10; n ¼ 159), ratio length to width 0.98–1.31 (1.15 6 0.06; n ¼
159), margins in anterior half of scutum diverge posteriorly, thereafter
gradually converging to narrowly rounded posterior margin, posterolateral
angular projections usually prominent. Coloration: ornamentation extensive, major portion of scutal surface covered with ivory-colored enameling;
pair of narrow ocular patches, pair of narrow, brown, cervical patches
which extend from cervical pits to posterior 1/3 of scutal length; central field
and areas lateral to cervical field in cervical grooves with hazy coloration or
with small patches which sometimes may form small, irregularly shaped
anteromedian or paracervical patches (or both). Cervical grooves distinct,
shallow. Small to medium-sized brown punctations dense, evenly distributed over scutum. Eyes oval, very slightly convex, positioned at mid-length.
Alloscutum (Fig. 1B): as illustrated; 11 festoons. Setae of alloscutum
relatively short (~0.05), moderately dense. Genital aperture (Fig. 3G): at
level of coxae II, narrowly V-shaped and bordered laterally by semioval
sclerites; preatrial fold flat. Spiracular plates (Fig. 3H): suboval; positioned
on ventral surface in unengorged specimens; perforated portion of dorsal
prolongation long and narrow, tapering to its apex; dorsal prolongation
with narrow, non-perforated portion anteriorly which may have small
ivory-colored spot; perforations small and fairly numerous. Gnathosoma
(Figs. 1B, 3I, J): length from palpal apices to cornual apices dorsally 0.60–
0.85 (0.74 6 0.05; n ¼ 156), width of basis capituli 0.30–0.67 (0.58 6 0.04; n
¼ 157), ratio length to width 1.15–2.16 (1.28 6 0.09; n ¼ 156). Basis capituli
(Figs. 1B, 3I, J): dorsally subrectangular; posterior margin nearly straight;
length 0.24–0.36 (0.30 6 0.02; n ¼ 156), ratio width to length 1.14–2.38 (1.96
6 0.13; n ¼ 156); cornua very short, broad, comprising a 6.50–62.00 (16.90
6 10.86; n ¼ 137) proportion of length of basis capituli or often virtually
absent; basis capituli dorsally with whitish enameling. Porose areas large,
circular (sometimes oval), deeply sunken with clearly circumscribed borders,
separated by space less than their width. Basis capituli ventrally
subrectangular; with convex posterior margin. Palpi (Figs. 1B, 3I, J): short
and broad; length dorsally (I–III segments) 0.36–0.51 (0.44 6 0.03; n ¼ 157),
width 0.19–0.30 (0.25 6 0.02; n ¼ 156), ratio length to width 1.50–2.15 (1.80
6 0.12; n ¼ 156), length of segments in descending order: 2, 3, 1, 4; segment
I well developed ventrally; segment II narrower at base and thereafter
parallel-sided, without clear denticle at posterior margin dorsally; segment
III subrectangular with broadly rounded apex; segments II and III with
whitish enameling on dorsal surfaces. Hypostome (Fig. 3J): club-shaped;
dental formula 3/3. Legs (Fig. 1B): of medium length, slender, with
extensive whitish enameling mostly on dorsal and lateral aspects. Coxae
(Fig. 3K, L): coxa I with long, triangular, closely spaced internal and
external spurs with tapering or narrowly rounded apices; external spur
usually slightly longer (but may be nearly equal to or slightly shorter) than
internal; both spurs of coxa I directed slightly posterolaterally; coxae II and
270
THE JOURNAL OF PARASITOLOGY, VOL. 100, NO. 3, JUNE 2014
TABLE I. Dermacentor everestianus, material studied.
No. of ticks*
?
/
China
1
1
1
2
1
1
3
5
4
1
1
9
1
N
Host
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
sheep
horse
sheep
sheep
horse
sheep
sheep
yak
Domestic camel
2
6
Domestic yak
3
1
2
2
Moschus sp.
Domestic sheep
Domestic yak
Ochotona sp.
Ochotona sp.
Ochotona sp.
Ochotona sp.
Ochotona sp.
Ochotona sp.
Ochotona sp.
Ochotona erythrotis
Ochotona sp.
Ochotona sp.
Ochotona erythrotis
Ochotona sp.
10
14
1
4
1
6
7
10
7
2
2
4
1
1
1
Ground
1
Domestic yak
1
2
3
1
2
1
1
1
187
1
1
5
sp.
dzo
dzo
sheep
Ochotona sp.
35
37
3
Ochotona
Domestic
Domestic
Domestic
5
4
1
Date
Collector†
Accession no.‡
L
2
1
Locality; altitude (m)
48
Domestic sheep
Domestic sheep
Lepus sp.
Apodemus sylvaticus
1
1
1
2
~300
Domestic cattle
reared in lab
Gansu, Jonê Xian
Gansu, Lintan Xian; 3,200
Gansu, Lintan Xian
Gansu, Luqu Xian; 3,000
Gansu, Maqu Xian
Gansu, Têwo Xian
Gansu, Xiahe Xian
Qinghai, Huangnan Tibetan A.P.;
3,550
Qinghai, Huangnan Tibetan A.P.;
3,550
Qinghai, Huangnan Tibetan A.P.;
3,550
Qinghai, Huangnan Tibetan A.P.
Qinghai, Menyuan Hui A.C.
Qinghai, Zêkog Xian
Qinghai; 3,800
Qinghai; 3,600
Qinghai; 3,600
Qinghai; 3,500
Qinghai; 3,500
Qinghai; 3,500
Qinghai; 3,500
Qinghai; 2,940
Qinghai; 2,600
Qinghai
Qinghai
Qinghai
Sichuan, Er-chu River, Bana-Jun;
3,505
Sichuan, Yulun-chu River, BanaJun; 3,536–3,962
Sichuan, Daocheng Xian, Sumdo;
4,000
Sichuan, Daocheng Xian, Sumdo;
4,000
Sichuan, Litang, Maoyaba; 4,000
Sichuan, Maerkang Xian
Sichuan, Maerkang Xian
Sichuan, Qianning Xian
Sichuan, upper Re-chu River;
3,871
Sichuan, Sêrtar; 3,881
Sichuan; 3,700
Tibet, nr. Chamdo, Lun-tonk-do
Tibet, Gar Xian, Zhaxigang,
Luma; 4,800
Tibet, Kangma Xian; 4,700
Tibet, Kangma Xian; 4,700
Tibet, Lhünzê Xian; 4,200
Tibet, Nang, Qujiang, Jiaojie;
3,200
Tibet, Nyalam Xian,
Xixiabangma
Tibet, Tingri Xian; 4,300
Tibet, Tinki Dzong; 4,572
Tibet
17 April 1982
23 May 1982
13 May 1982
24 May 1985
14 May 1982
20 April 1982
April 1981
13 April 1964
L
17 June 1964
IZCAS
IZCAS
IZCAS
IZCAS, D-057-14
IZCAS
IZCAS
IZCAS
IZCAS
IZCAS
17 June 1964
L
IZCAS
June 1973
April 1958
17 June 1964
25 July 1964
25 July 1964
25 July 1964
5 August 1964
6 August 1964
8 August 1964
8 August 1964
3 June 1964
27 July 1964
4 August 1964
6 July 1964
7 August 1964
NIPB
PKK, ANK
IZCAS
IZCAS, D-047-01
IZCAS, D-019-03
IZCAS, D-020-03
IZCAS, D-020-02
IZCAS, D-019-01
IZCAS, D-019-12
IZCAS, D-019-02
IZCAS, D-020-11
IZCAS, D-019-07
IZCAS, Im84
IZCAS, D-020
IZCAS, D-020-08
IZCAS, Im82
IZCAS, D-020-06
ZIRAS 586
12 March 1901
PKK, ANK
ZIRAS 587
6 June 1982
C
IZCAS, D-059-05
6 June 1982
22 July 1983
9 May 1961
9 May 1961
1977
February 1901
4 June 1982
13 February 1901
21 April–2 May 1992
9 August 1974
6 November 1966
IZCAS
C
PKK, ANK
PKK, ANK
LT
7 April 1964
2 May 1924
1963
IZCAS, D-059-11
IZCAS, D-047-02
IZCAS
IZCAS
ZIRAS 585
IZCAS, Im107
IZCAS, D-060-14
ZIRAS 588
IZCAS, D-048-06
IZCAS,
IZCAS,
IZCAS,
IZCAS,
D-056-04
D-056-08
D-055-04
D-055-13
IZCAS, D-047-07
RWGH
RX
IZCAS, D-067-02
BM 1930.1.10.17
USNMENT 00714960
IZCAS, Im34
APANASKEVICH ET AL.—DERMACENTOR EVERESTIANUS
271
TABLE I. Continued.
No. of ticks*
Nepal
1
60
48
36
1
2
7
12
3
8
Host
21
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
Domestic
9
8
2
2
1
26
1
6
Domestic goat
Domestic dzo
Domestic goat
Pseudois nayaur
Naemorhedus goral
293
358
1
4
2
11
63
46
30
3
9
14
24
6
15
1
1
2
2
1
5
192
417
sheep
sheep
sheep
horse
cattle
cattle
cattle
horse
cattle
cattle
cattle
horse
cattle
goat
dzo
goat
goat
goat
Locality; altitude (m)
Mustang, Jomoson; 2,740
Mustang, Jomoson; 2,740
Mustang, Jomoson; 3,353
Mustang, Geling; 3,810
Mustang, Geling; 3,810
Mustang, Geling; 3,810
Mustang, Geling; 3,810
Mustang, Geling; 3,810
Mustang, Geling; 3,810
Mustang, Geling; 3,810
Mustang, Geling; 3,810
Mustang, Geling; 3,810
Mustang, Geling; 3,810
Mustang, Geling; 3,810
Mustang, Muktinath; 3,581
Mustang, Muktinath; 3,581
Mustang, Muktinath; 3,581
Mustang, Narsing Khola
(Chusang); 2,896
Mustang, Lho Mantang; 3,810
Mustang, Gyalin Goan; 3,658
Mustang, Gyalin Goan; 3,658
Dolpa, Dhorpatan; 2,728
25 mi. W of Dhaulagheri
mountain
Date
Collector†
Accession no.‡
5 February 1970
5 February 1970
9 February 1970
20 March 1970
23 March 1970
22 March 1970
18 May 1970
22 March 1970
2 June 1970
17 March 1970
19 March 1970
23 March 1970
17 March 1970
4 June 1970
3 March 1970
28 February 1970
27 February 1970
6 June 1970
RMM
RMM
RMM
MKL
MKL
MKL
MKL
MKL
MKL
MKL
MKL
MKL
MKL
MKL
MKL
MKL
MKL
MKL
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
00714033
00714386
00714345
00714079
00714928
00714215
00714686
00714986
00714267
00714500
00714814
00714643
00714339
00714578
00714128
00714141
00714966
00714949
28 May 1970
22 May 1970
22 May 1970
6 February 1969
October 1984
MKL
MKL
MKL
RMM
JWV
USNMENT
USNMENT
USNMENT
USNMENT
USNMENT
00714524
00714216
00714817
00714230
00714285
Total
* N–nymphs; L–larvae.
† ANK–A. N. Kaznakov; C–Cui; JWV–J. W. Vanderbeek; L–Lu; LT–Li Tiesheng; MKL–M. K. Lama; NIPB–Northwest Institute of Plateau Biology;
PKK–P. K. Kozlov; RMM–R. M. Mitchell; RWGH–R. W. G. Hingston; RX–Rongman Xu.
‡ BM–Natural History Museum (London); IZCAS–Institute of Zoology, Chinese Academy of Sciences (Beijing); USNMENT–U.S. National Tick
Collection (Statesboro); ZIRAS–Zoological Institute, Russian Academy of Sciences (St. Petersburg).
III each with larger triangular external spur with tapering apex and smaller
broadly arcuate internal spur; coxa IV with large triangular external spur
with tapering apex; coxae with or without enameling. Trochanter I (Fig.
3M) with short, broad, triangular dorsal spur with rounded apex. Genu IV
length 0.61–0.80 (0.71 6 0.05; n ¼ 30), width 0.25–0.35 (0.30 6 0.03; n ¼
30), ratio length to width 2.00–2.58 (2.34 6 0.13; n ¼ 30).
Nymph (Fig. 4A–F): Idiosoma: suboval, widest at level of posterior
margin of coxae IV. Scutum (Fig. 4A): length 530–615 (558 6 29; n ¼ 7),
width 530–590 (554 6 19; n ¼ 7), ratio length to width 0.95–1.04 (1.01 6
0.03; n ¼ 7); pentagonal, posterior margin broadly rounded, posterolateral
depressions very slight or indistinct, posterolateral angles indistinct;
cervical grooves distinct, moderate. Setae approximately 13–17 pairs,
length of setae in posterior portion of central field 55–62 (60 6 3; n ¼ 5).
Eyes suboval, slightly bulging, located on lateral margins of scutum in
posterior 1/2; length of scutum portion posterior to eyes 195–210 (203 6
6; n ¼ 7), ratio of scutum length to length of its portion posterior to eyes
2.65–2.93 (2.75 6 0.09; n ¼ 7). Number of pairs of dorsal setae on
alloscutum 48–57 (51; n ¼ 6); length of setae in anterolateral portion of
alloscutum 65–77 (70 6 4; n ¼ 7); setae in central rows length 47–59 (53 6
4; n ¼ 7); setae with denticles (Fig. 4B). Fovea with 3 or 4 (in 1 case 2
openings present on 1 of 2 fovea) openings. Three or 4 pairs of setae at the
level of coxae II ventrally (sometimes 2 or 5 setae present on 1 of its sides).
Spiracular plates (Fig. 4C): subcircular, large, longitudinal diameter of
spiracular plate larger than longitudinal diameter of sclerite around anal
valves; submarginal row of perforations complete. Gnathosoma (Fig. 4D,
E): length from palpal apices to posterior dorsal margin of basis capituli
250–310 (286 6 19; n ¼ 7), width at apices of dorsolateral projections 300–
327 (312 6 10; n ¼ 7); ratio length to width 0.83–0.97 (0.92 6 0.05; n ¼ 7).
Basis capituli (Fig. 4D, E): dorsally subhexagonal, with moderate and
bluntly pointed lateral projections; auriculae moderate, tapering or
narrowly blunt at apices ventrally; with 1 pair of ventral setae and 1
pair of posthypostomal setae. Palpi (Fig. 4D, E): elongate, length 180–205
(191 6 8; n ¼ 7), maximal width 62–70 (66 6 3, n ¼ 7), ratio length to
width 2.67–3.08 (2.90 6 0.16; n ¼ 7); segment I well developed ventrally,
cylindrical, clear suture between segments II and III, segment II the
longest, narrow proximally and gradually expanding distally, segment III
broadly rounded at apex; segment I with 1 ventral seta, segment II with 4
dorsal and 3 ventral setae, segment III with 5 dorsal and 2 ventral setae.
Hypostome (Fig. 4E): length from apex to the level of posthypostomal
setae 155–200 (169 6 15; n ¼ 7), width at narrowest portion 50–60 (53 6
3; n ¼ 7), ratio length to width 2.95–3.33 (3.17 6 0.12; n ¼ 7); club-shaped,
dental formula distal approximately 4 (3–6) rows 3/3, proximal
approximately 4 rows 2/2; 3/3 portion of hypostome comprises slightly
more than 1/2 of its total length (ratio avg. 2.4). Coxae (Fig. 4F): coxa I
with 2 relatively short, triangular posterior spurs with bluntly tapering
apices, internal spur slightly or considerably shorter than triangular
external spur; spurs on coxae II and III moderate, triangular; spur on coxa
IV triangular, small to moderate, sometimes poorly developed, not
protruding beyond coxae posterior margin; coxal ‘‘pores’’ (openings of
dermal glands or sensilla usually situated close to mid-lateral margin of
coxae) absent. Genu IV: length 215–240 (230 6 8; n ¼ 7), width 80–97 (87
6 9; n ¼ 3), ratio length to width 2.36–2.71 (2.58 6 0.19; n ¼ 3).
Larva (Fig. 4G–J): Idiosoma: suboval, widest at level of coxae III.
Scutum (Fig. 4G): length 270–355 (307 6 22; n ¼ 19), width 365–465 (398
6 29; n ¼ 20), ratio length to width 0.68–0.83 (0.77 6 0.03; n ¼ 19);
pentagonal, posterior margin broadly rounded with narrowly rounded
apex, posterolateral marginal depressions indistinct; cervical grooves as
faint, shallow depressions. Eyes suboval, slightly bulging, located on
lateral margins of scutum slightly posterior to scutum midlength; length of
scutum portion posterior to eyes 90–120 (102 6 7; n ¼ 19), ratio of scutum
length to length of its portion posterior to eyes 2.76–3.50 (3.02 6 0.15; n ¼
19). Setae 3 pairs, Sc2 27–41 (36 6 6; n ¼ 7), Sc3 32–47 (39 6 4; n ¼ 15).
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FIGURE 1. Dermacentor everestianus, dorsally. (A) Male (Nepal, Mustang, Jomoson, USNMENT 00714386). (B) Female (Nepal, Mustang, Geling,
USNMENT 00714686). Bars ¼ 1 mm.
APANASKEVICH ET AL.—DERMACENTOR EVERESTIANUS
273
FIGURE 2. Dermacentor everestianus, variations in the coloration of male conscutum and female scutum. Male: (A–C) Nepal, Mustang, Jomoson,
USNMENT 00714386. (D–F) China, Qinghai, Huangnan Tibetan Autonomous Prefecture, IZCAS. Female: (G–H) Nepal, Mustang, Jomoson,
USNMENT 00714386. (I) China, Qinghai, Huangnan Tibetan Autonomous Prefecture, IZCAS. Bars ¼ 1 mm.
Dorsal setae of alloscutum 10 pairs; 2 pairs of central dorsals, Cd1 27–39
(33 6 3; n ¼ 15), Cd2 24–32 (27 6 2; n ¼ 15); 8 pairs of marginal dorsals,
Md1 27–37 (32 6 3; n ¼ 13), Md8 21–25 (23 6 1; n ¼ 12). Ventral setae 14
pairs plus 1 pair on anal valves; 3 pairs of sternals, St1 48–68 (61 6 5; n ¼
19); 2 pairs of preanals, Pa1 44–63 (54 6 4; n ¼ 19), Pa2 40–56 (46 6 5; n ¼
13); 4 pairs of premarginals, Pm1 59–68 (63 6 3; n ¼ 14); 5 pairs of
marginal ventrals, Mv1 24–31 (27 6 2; n ¼ 16), Mv5 25–30 (27 6 2; n ¼
17). Gnathosoma (Fig. 4H, I): length from palpal apices to posterior
dorsal margin of basis capituli 135–200 (166 6 15; n ¼ 20), width at apices
of dorsolateral projections 162–204 (178 6 10; n ¼ 20); ratio length to
width 0.78–1.00 (0.93 6 0.05; n ¼ 20). Basis capituli (Fig. 4H, I): dorsally
hexagonal, with moderate and narrowly blunt lateral projections;
ventrally rectangular with poorly developed auriculae. Posthypostomal
setae 1 pair. Palpi (Fig. 4H, I): elongate, length 97–122 (105 6 9; n ¼ 20),
width 45–55 (50 6 2, n ¼ 20), ratio length to width 1.82–2.72 (2.13 6 0.24;
n ¼ 20); segment I well-developed, cylindrical, faint suture between
segments II and III medially, segment III with indistinct or broad fold-like
denticle ventrally; segment I without setae, segment II with 4 dorsal and 2
ventral setae, segment III with 5 dorsal and 1 ventral setae. Hypostome
(Fig. 4I): length from apex to the level of posthypostomal setae 82–112 (91
6 9; n ¼ 20), minimal width 25–31 (27 6 2; n ¼ 20), ratio length to width
3.00–3.60 (3.32 6 0.19; n ¼ 20); club-shaped, dental formula 2/2
throughout length, approximately 4 or 5 larger denticles in median files;
denticulated portion comprises more than 1/2 of hypostomal length.
Coxae (Fig. 4J): coxa I with moderate and triangular spur with tapering
apex, coxae II and III each with relatively large, triangular spur. Genu I:
length 115–140 (124 6 8; n ¼ 20), width 61–71 (64 6 2; n ¼ 18), ratio
length to width 1.80–2.24 (1.93 6 0.10; n ¼ 18).
Taxonomic summary
Holotype: Male, Tinki Dzong (~28818 0 N, 8885 0 E), Tibet, China, 4,572
m alt., 2.V.1924, R. W. G. Hingston; deposited in the Natural History
Museum, London, U.K. (BMNH 1930.1.10.14). We have examined it.
Synonyms: Dermacentor birulai Olenev, 1927; Dermacentor abaensis
Teng, 1963.
We have examined the type series of both species and confirmed their
synonymy with D. everestianus. Dermacentor birulai: Lectotype: male,
upper reaches of Re-chu, Blue River basin, Eastern Tibet, 3,871 m alt.,
II.1901, P. K. Kozlov and A. N. Kaznakov. Paralectotypes: female with
the same label data as for lectotype; male, Bana-Jun settlement, Julun-chu
River and valley of adjacent rivers, Blue River basin, Eastern Tibet, 3,536–
3,962 m alt., 12.III.1901, P. K. Kozlov and A. N. Kaznakov; male, Er-chu
River, Bana-Jun settlement, 3,505 m alt., P. K. Kozlov and A. N.
Kaznakov. Lectotype and paralectotype are deposited in the ZIRAS.
Dermacentor abaensis: Holotype: male, from domestic dzo (yak 3
domestic cattle), Maerkang Xian (¼ Barkam Xian), Aba Zangzu and
Qiangzu Autonomous Prefecture, Sichuan, China, 9.V.1961. Allotype
(female) and paratypes (male and 2 females) with the same label data as
for holotype. All deposited in the IZCAS. Whereabouts of the rest of the
paratypes (10 males and 7 females) are unknown. The vial containing the
holotype also has another apparently paratype male, thus making the
holotype undistinguishable from the rest of the type series.
Distribution and hosts: To date, D. everestianus is known only from
China (Gansu, Qinghai, Sichuan, and Tibet Provinces) and Nepal (Dolpa,
Mustang, and Solukhumbu Districts) (Fig. 5).
Examined adults of D. everestianus were collected from domestic
ungulates such as camel (species is not stated), cattle, dzo, goat, horse,
sheep, yak, and wild ungulates, namely Himalayan goral, Naemorhedus
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FIGURE 3. Dermacentor everestianus, adults. Male (Nepal, Mustang, Jomoson, USNMENT 00714386): (A) Spiracular plate. Bar ¼ 0.1 mm. Arrows
indicate orientation of spiracular plate (a–anterior; d–dorsal). (B) Gnathosoma dorsally. Bar ¼ 0.2 mm. (C) Gnathosoma ventrally. Bar ¼ 0.2 mm. (D)
Coxae. Bar ¼ 0.5 mm. (E) Coxa I. Bar ¼ 0.1 mm. (F) Trochanter I dorsally. Bar ¼ 0.1 mm. Female (Nepal, Mustang, Geling, USNMENT 00714686): (G)
Genital structures. Bar ¼ 0.1 mm. (H) Spiracular plate. Bar ¼ 0.1 mm. Arrows indicate orientation of spiracular plate (a–anterior; d–dorsal). (I)
Gnathosoma dorsally. Bar ¼ 0.2 mm. (J) Gnathosoma ventrally. Bar ¼ 0.2 mm. (K) Coxae. Bar ¼ 0.5 mm. (L) Coxa I. Bar ¼ 0.1 mm. (M) Trochanter I
dorsally. Bar ¼ 0.1 mm.
APANASKEVICH ET AL.—DERMACENTOR EVERESTIANUS
275
FIGURE 4. Dermacentor everestianus, immature stages. Nymph (China, Sichuan, Sêrtar, IZCAS): (A) Scutum. Bar ¼ 100 lm. (B) Setae of alloscutum.
Bar ¼ 50 lm. (C) Spiracular plate. Bar ¼ 50 lm. Arrows indicate orientation of spiracular plate (a–anterior; d–dorsal). (D) Gnathosoma dorsally. Bar ¼
100 lm. (E) Gnathosoma ventrally. Bar ¼ 100 lm. (F) Coxae. Bar ¼ 100 lm. Larva (China, Tibet, Lhünzê Xian, IZCAS): (G) Scutum. Bar ¼ 100 lm. (H)
Gnathosoma dorsally. Bar ¼ 50 lm. (I) Gnathosoma ventrally. Bar ¼ 50 lm. (J) Coxae. Bar ¼ 100 lm.
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THE JOURNAL OF PARASITOLOGY, VOL. 100, NO. 3, JUNE 2014
FIGURE 5. Dermacentor everestianus, map of geographical distribution. Star indicates the type locality and filled circles represent confirmed localities.
goral (Hardwicke), bharal, Pseudois nayaur (Hodgson), and musk deer,
Moschus sp. Nymphs and larvae were collected from hare, Lepus sp., and
pika, Ochotona sp. A nymph was also found on the long-tailed field
mouse, Apodemus sylvaticus (Linnaeus), while larvae also were collected
from Chinese red pika, Ochotona erythrotis (Büchner). Teng (1963) also
recorded one female (as D. abaensis) being collected from an Asian black
bear, Ursus thibetanus Cuvier. Hoogstraal et al. (1970) recorded a nymph
(as D. everestianus) collected from Apodemus sp. in Nepal. Mitchell (1979),
without indicating the stages collected, records D. everestianus from
woolly hare, Lepus oiostolus Hodgson in Nepal. Teng and Jiang (1991)
mentioned adults being recorded from an unidentified hare (as D.
everestianus) and Alpine musk deer, Moschus chrysogaster (Hodgson)
(as D. abaensis). These authors also stated that larvae and nymphs
parasitize rodents (as D. everestianus), the large-eared field mouse,
Apodemus latronum Thomas, and Moupin pika, Ochotona thibetana
(Milne-Edwards) (as D. abaensis). Based on studied material, most of the
adults were collected in the period from February to June and 1 collection
was made in October. Most of the larvae and nymphs were collected from
June to August with 1 collection taken in November.
Disease relationships: Rickettsia raoultii-like bacteria were isolated from
D. everestianus collected at Namuco Lake in Tibet (Wang et al., 2012).
Remarks
Relationships of D. everestianus with other Palearctic Dermacentor
species remain unknown. Possibly this species is more related to other
Dermacentor species living in the high mountains of Central Asia such as
Dermacentor raskemensis Pomerantzev, 1946, Dermacentor pavlovskyi
Olenev, 1927, and Dermacentor montanus Filippova & Panova, 1974.
Males of all of these species always have no patches of brown on lateral
fields (parts of conscutum between its lateral margin and marginal groove)
of the conscutum. From D. pavlovskyi and D. montanus, males and
females of D. everestianus can easily be distinguished by the absence of
very large spurs ventrally at distal ends of genua and tibiae II–IV; from
Dermacentor raskemensis, adults of D. everestianus can be easily
differentiated by very short dorsal cornua and spur on trochanters I.
From other potentially sympatric species, such as Dermacentor nuttalli
Olenev, 1929 and Dermacentor silvarum Olenev, 1931, D. everestianus
adults are distinguished by generally lighter coloration, coloration pattern,
and clearly defined long and narrow dorsal prolongation of the spiracular
plates. Because the differentiation of Dermacentor species based on their
immature stages remains poorly studied, we can only provide a tentative
diagnosis for the nymph and larva of D. everestianus. The nymph of D.
everestianus can be distinguished from those of other species found in the
region (D. nuttalli and potentially D. raskemensis and D. silvarum) by the
combination of the following characters: numerous setae on alloscutum
(.48 pairs) (,42 pairs in D. nuttalli and D. raskemensis), large spiracular
plates with their longitudinal diameter exceeding that of sclerotized ring
around anal valves (smaller spiracular plates in D. nuttalli and D.
raskemensis), moderate lateral projections of basis capituli with blunt
apices situated slightly posterior to basis capituli midlength dorsally
(longer and sharper lateral projections in D. silvarum), relatively short
spurs on coxae I with internal spur being considerably shorter than
external (longer and more subequal spurs in D. silvarum and often in D.
nuttalli), internal spur of coxae I triangular (broadly rounded in D.
raskemensis), and moderate triangular spur on coxae IV (small in D.
raskemensis). Larvae of D. everestianus, surprisingly, can easily be
distinguished from those of other species found in the region by the
greatly elongated posterior portion of scutum where the eyes are situated
just posterior to scutum midlength (slightly elongated posterior portion of
scutum in other species with eyes situated clearly in posterior third of
scutum).
DISCUSSION
Based on examination of the type specimens of D. everestianus,
D. birulai, and D. abaensis, as well as of numerous specimens of
all stages identified as D. everestianus and D. abaensis, we
conclude that D. birulai and D. abaensis should be treated as
junior synonyms of D. everestianus. Nevertheless, it has to be
APANASKEVICH ET AL.—DERMACENTOR EVERESTIANUS
noted that D. everestianus shows fairly clear geographical
morphological variability, which had its reflection in recognition
of D. birulai and D. abaensis in the past. Teng (1963) listed the
following characters which distinguish adults of D. abaensis from
D. everestianus: male has shorter and blunter spur on trochanter I,
punctations of conscutum denser and not uniform, longer and
more pronounced marginal groove on conscutum, and coxae I–IV
without enameling; female has wider basis capituli, porose areas
oval and oblique in position, punctations of various size on
scutum, and more long and robust spur on coxae IV. We carefully
examined all differential characters listed above and came to the
following conclusions.
Dorsal spur on trochanter I in male is relatively short and blunt
in both taxa. The length of this spur and degree of its bluntness is
slightly varied individually among both species. Based on this
character it is virtually impossible to differentiate males of D.
abaensis from those of D. everestianus.
We would only partially agree with Teng (1963) that males of
D. abaensis have denser punctations on conscutum in comparison
to those found in males of D. everestianus. Both taxa have
approximately equally punctated conscutum. However, it is true
that males of former D. abaensis often have slightly larger
punctations that may give it an appearance of a more-punctated
tick. Again this character also varies individually and generally
does not provide clear differentiation (compare Fig. 2C and 2D).
In fact, the punctation often is of the same size and uniformity but
the area of dark-brown background surrounding each punctation
is larger in D. abaensis, thus leading to the impression that this
tick is denser and less uniformly punctated. It also has to be noted
that the density and size of punctations often are variable
characters in many tick species, both individually and geographically. For instance, western populations of Hyalomma asiaticum
Schulze & Schlottke, 1929 have more-densely punctated conscutum in comparison to central or eastern populations in which
it may be absolutely smooth (Apanaskevich and Horak, 2010). In
the case of D. everestianus and D. abaensis there is no alternative
state of this character which would clearly differentiate males of
these 2 taxa based on punctations pattern. In fact, many
specimens cannot be distinguished by this character. We would
assume that the slight difference in size and density of the
punctations may be due to geographic variations.
The length of marginal groove in both D. everestianus and D.
abaensis is the same, but because D. abaensis often has larger
punctations or a larger darker area around punctations (or both)
aligning marginal grooves, the latter appear more pronounced.
Again, this character is variable and cannot be used to
discriminate these 2 taxa.
It is true that many males of D. everestianus have coxae I–IV
with enameling while males of D. abaensis have no ivory-colored
enameling on their coxae. We suppose that this character
generally is a reflection of total coloration (see below the
discussion on this character). Here we can only add that males
of D. everestianus without ornamentation on coxae can be found
regularly and, in contrast, some males of D. abaensis have slight
ornamentation on coxae.
Breadth of basis capituli in females of D. everestianus: 0.48–0.67
(0.59 6 0.04; n ¼ 122), ratio length of gnathosoma to basis
capituli width: 1.15–1.41 (1.27 6 0.05; n ¼ 121), ratio basis
capituli width to basis capituli length: 1.73–2.38 (1.96 6 0.10; n ¼
121). Breadth of basis capituli in females of D. abaensis: 0.30–0.67
277
(0.56 6 0.06; n ¼ 35), ratio length of gnathosoma to basis capituli
width: 1.18–1.36 (1.27 6 0.05; n ¼ 34), ratio basis capituli width to
basis capituli length: 1.77–2.20 (1.97 6 0.12; n ¼ 34). As can
clearly be seen, it would be impossible to distinguish D. abaensis
females from those of D. everestianus based on a character of
broader basis capituli.
More oval shape and oblique position of porose areas is an
individually variable character. Most of the specimens of both
taxa would have nearly round porose areas, although slightly oval
porose areas are not rare. This character cannot be used to
separate females of D. abaensis from those of D. everestianus.
Size difference in punctations of scutum is an individually or
geographically variable (or both) feature in D. everestianus, as
discussed above. As in the case of males, females of D. abaensis
may have slightly larger punctations in comparison with slightly
finer punctated D. everestianus.
It is difficult to estimate the robustness of the spur on coxae IV.
Based on our observations it is an individually variable character,
where some specimens will have a more slender and tapering spur;
and others will have a more broad and rounded spur. It cannot be
used to differentiate these 2 taxa.
In conclusion we can state that none of the characters proposed
by Teng (1963) to differentiate adults of D. abaensis from those of
D. everestianus can be used with confidence. Some of the proposed
characters, such as length and bluntness of dorsal spur of
trochanters I in male and robustness of spur on coxae IV in
female, are based on finer individual variations. But some
characters, such as slight variations in punctations and coloration,
may have geographical background.
In addition to Teng’s observations on the morphological
characters of formerly valid D. abaensis, we can add that the
adults of D. everestianus collected from the western part of its
range, i.e., along the Himalayans, are generally more lightly ivory
colored while adults from the eastern part of the range, i.e.,
eastern Tibet (¼ D. abaensis and D. birulai), have larger brown
patches on conscutum and scutum, thus making the tick darker in
appearance. Intensity of ivory enameling is generally individually
and geographically variable in many species of Dermacentor.
Thus, specimens of Dermacentor albipictus (Packard, 1869) from
Arizona have very much reduced ornamentation of conscutum
and are often entirely inornate while specimens from Montana
will mostly be very brightly ornate (Cooley 1938; our data).
Eastern European Dermacentor marginatus (Sulzer, 1776) is
considerably less ornate than the specimens of this species
collected in Asiatic part of its range (Filippova and Plaksina,
2005; our unpubl. data). Thus, it is not surprising that western
populations of D. everestianus are lighter colored in comparison
to those collected in eastern Tibet. Again, this is not absolute, i.e.,
darker specimens can be found in the west and lighter in the east.
We had very sparse material of larvae and nymphs and they
showed some slight differences in measurements between western
and eastern specimens. Larvae from eastern Tibet have slightly
shorter and broader palps and hypostome (16 larvae from
Qinghai and unknown locality in eastern Tibet: ratio length to
width of palps avg. 2.02 and ratio length to width of hypostome
avg. 3.27) in comparison with those from the Himalayans (4
larvae from Tibet: ratio length to width of palps avg. 2.55 and
ratio length to width of hypostome avg. 3.51). The number of
denticles in files on the hypostome is slightly different, namely
because nymphs of D. everestianus from Sichuan have 3–5 larger
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THE JOURNAL OF PARASITOLOGY, VOL. 100, NO. 3, JUNE 2014
denticles while the only nymph from Tibet has 5 or 6 larger
denticles in median files. Larvae collected in Qinghai mostly have
4 larger denticles while larvae collected in Tibet have 5 larger
denticles in median files. It would be plausible to assume that
these slight differences may reflect geographic variability in the
immature stages but, unfortunately, it is difficult to estimate their
importance due to very low sampling numbers. In any case, the
observed features are easily fit to the single species variations.
Summarizing Teng’s and our observations in all stages of D.
everestianus and the formerly valid D. abaensis, we can firmly
state that there is not even a single discrete character allowing us
to identify D. abaensis on any of its life stages with confidence. Its
discrimination is based on individually and geographically
variable characters such as coloration and punctations. More
importantly, we were unable to find any meaningful differences in
the immature stages that would have indicated species independency with certainty. On the opposite side, throughout its
distributional range all stages of D. everestianus possess a number
of very distinct morphological features allowing identification of
this species among any other Dermacentor.
We hope that this work will promote more-intensive collections
of D. everestianus, especially its immature stages, in the entire
region. This would provide more data for morphological and
molecular analysis of the intraspecific structure of this rare
Dermacentor species of mountainous regions.
ACKNOWLEDGMENTS
We express our sincere thanks to Dr. Janet Beccaloni (Natural History
Museum, London, U.K.) for making the holotype of Dermacentor
everestianus available for examination. The authors are in debt to Dr.
Gerrit Uilenberg for his careful editing of the manuscript. Dmitry A.
Apanaskevich’s part of this project was supported by Grant Number
R15AI096317 from the National Institute of Allergy and Infectious
Diseases. The content is the sole responsibility of the authors and does not
necessarily represent the official views of the National Institute of Allergy
and Infectious Diseases or the National Institutes of Health. Wei Duan’s
work was partially supported by NSFC program J1210002.
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