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SYSTEMATICS
A New Genus and Two New Species of the Family
Pygmephoridae (Acari: Heterostigmata) Associated with
Beetles (Insecta: Coleoptera)
V. RAHIMINEJAD,
1
H. HAJIQANBAR,
1,2
A. A. KHAUSTOV,
3
AND A. A. TALEBI
1
Ann. Entomol. Soc. Am. 108(5): 893–901 (2015); DOI: 10.1093/aesa/sav073
Published online September 11, 2015
ABSTRACT Metapygmephorellus Rahiminejad, Hajiqanbar & Khaustov gen. nov. (Acari: Prostigmata:
Pygmephoridae) (type species Metapygmephorellus colydius Rahiminejad & Hajiqanbar sp. nov.) is de-
scribed and illustrated based on females phoretic on Colydium elongatum (F., 1787) and Dorcus paralle-
lipipedus (L., 1758) (Coleoptera: Zopheridae and Lucanidae), respectively, which were collected from
the forests in northern Iran. Another new species, Metapygmephorellus orientalis Khaustov sp. nov., col-
lected from the bark beetle Hylurgops interstitialis Chapuis, 1875 (Col.: Curculionidae), from Far East
Russia is also described. Pygmephorellus brachycercus Cross & Moser, 1971 is transferred to Metapyg-
mephorellus gen. nov. A key to species of the genus Metapygmephorellus is provided.
KEY WORDS mite, phoresy, subcortical, Iran, Russia
Symbiotic relationships with insects are typical in many
Heterostigmata (Acari: Trombidiformes: Prostigmata) in-
clusive of pygmephorid mites, which are often phoretic
(Kaliszewski et al. 1995). To date, the Pygmephoridae
Cross, 1965 encompasses 28 genera and more than 300
species distributed worldwide (Zhang et al. 2011, Khaus-
tov 2015). All of pygmephorid mites are probably fungiv-
orous (Khaustov 2008b) and inhabit soil, forest litter, and
nests of small mammals and insects (Walter et al. 2009).
Many pygmephorid mites utilize ephemeral resources,
such as dung or nest. Females of such genera are char-
acterized by phoretic associations with diverse groups of
insects, especially Coleoptera, Hymenoptera, and Dip-
tera (Kaliszewski et al. 1995, Walter et al. 2009). The
most specialized pygmephorid mites are phoretic on var-
ious beetles such as dung beetles (hosts of the genera
Pediculaster Vitzthum, 1931; Geotrupophorus Mahunka,
1970; Pygmephorellus Cross & Moser, 1971; Spatulapho-
rus Rack, 1993; and Pseudopygmephorellus Khaustov,
2008), scolytid and cerambycid beetles (hosts of the gen-
era Elattoma Mahunka, 1969 and Microdispodides Vitz-
thum, 1914) (Khaustov 2008a, Rahiminejad et al. 2011).
During a study of heterostigmatic mites phoretic on
subcortical insects, a new genus and two new species of
Pygmephoridae were revealed in Iran and Far East
Russia. Cross and Moser (1971) described Pygmephor-
ellus brachycercus Cross & Moser, 1971 collected from
inner surface of pine bark in USA. In this paper we
consider P. brachycercus as another member of the ge-
nus Metapygmephorellus gen. nov.
The purpose of this paper is to describe a new genus
and two new species of the family Pygmephoridae and
provide a key to species of the newly described genus
Metapygmephorellus gen. nov.
Material and Methods
The Mite specimens, after detachment from host
beetles, were cleared in lactophenol and mounted in
Hoyer’s medium. The morphology of the mites was
studied by a light microscope with phase contrast
(Olympus BX51, Tokyo, Japan) and DIC contrast (Axio
Imager.A2, Carl Zeiss, Germany). The terminology of
idiosoma and legs follows that of Lindquist (1986);the
nomenclature of subcapitular setae and the designation
of cheliceral setae follow that of Grandjean (1944,
1947), respectively. The classification system of Pygme-
phoroidea follows that of Khaustov (2004, 2008b). All
measurements in the description are given in microme-
ters (lm) for the holotype and (when available) five
paratypes (in parentheses). For leg chaetotaxy, the
number of solenidia is given in parentheses. Details of
geographical position were recorded using a global po-
sitioning system (GPS model: eTrex).
Nomenclature. This paper and the nomenclatural
acts it contains have been registered in Zoobank (www.
zoobank.com), the official register of the International
Commission on Zoological Nomenclature. The LSID
(Life Science Identifier) number of the publication is:
urn:lsid:zoobank.org:pub:91A64777-FC48-4B8F-
B9EF-3DB2371AF0D0.
Systematics
Family Pygmephoridae Cross, 1965
Genus Metapygmephorellus Rahiminejad, Hajiqan-
bar & Khaustov gen. nov.
1
Department of Entomology, Faculty of Agriculture, Tarbiat Mod-
ares University, 14115-336, Tehran, Iran.
2
Corresponding author, e-mail: hajiqanbar@modares.ac.ir.
3
Tyumen State University, Tyumen, 625003 Russia.
V
C
The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America.
All rights reserved. For Permissions, please email: journals.permissions@oup.com
Type species: Metapygmephorellus colydius Rahimi-
nejad & Hajiqanbar sp. nov.
(urn:lsid:zoobank.org:act:A660B55F-6103-4289-
A3F1-27805B009A42)
Diagnosis of Adult Female
Adult females of the new genus are characterized by
following character states. Gnathosomal capsule dor-
sally with two pairs of setae (cha, chb), dorsolateral
postpalpal setae (pp), and ventrally with vestiges of sub-
capitular setae n only. Posterior part of prodorsal shield
covering anterior part of tergite C. Coxal fields I with
three pairs of setae (1a,1b,1c), seta 1b bifurcate; coxal
fields II with two pairs of setae 2a and 2c. Posterior
margin of posterior sternal plate tripartite. Leg I four-
segmented, with large sedentary claw on massive tibio-
tarsus; genu I with four or three setae; genu II with
two setae (l
0
and v
0
); seta d of femur I hooked.
Gnathosoma. Spherical in shape; dorsally with
two pairs of cheliceral setae cha, chb, dorsolateral post-
palpal setae (pp) and palpal dFe, dGe, ventrally with
one pair of pits (vestiges of subcapitular setae n), sub-
capitular setae m absent. Palps ventrally with relatively
small accessory setigenous structure and tiny soleni-
dion. Pharyngeal system difficult to discern, pump 1
smallest, pump 2 largest and striated, pump 3 oval-
shaped.
Idiosoma. Dorsal shields strongly sclerotized and
punctate. Prodorsal shield with one pair of single-
chambered oval stigmata, three pairs of simple setae
(v
1
, v
2
, sc
2
), and one pair of capitate trichobothria.
Opisthosomal setation complete, three pairs of round
cupuli (ia, im,andih) on tergites D, EF, and H,
respectively. Ventral apodemes 1 (ap1) and 2 (ap2)
joined with prosternal apodeme (appr), sejugal apo-
deme (apsej) thickened and joined with appr, apo-
demes 3 weak and diffuse, apodemes 4 reaching to
base of trochanter III, poststernal apodeme (appo)
short, apodeme 5 absent; posterior border of postster-
nal plate tripartite. Coxal fields I with three pairs of
setae 1a,1b,and1c,seta1b bifurcate; Coxal fields II
with two pairs of setae 2a and 2b; Coxal fields III with
three pairs of setae 3a,3b, and 3c; coxal fields IV with
three pairs of setae 4a,4b,and4c; pseudanal segment
with three pairs of setae (ps
1
, ps
2
,andps
3
); genital
sclerites weakly sclerotized, usually represented by oval
posterior genital sclerite. Tiny anterior genital sclerite
sometimes evident.
Legs. Legs I four-segmented, tibiotarsus (TiTa) with
one thick and stout claw. Legs II–IV: five-segmented,
with pair of simple claws and small empodium. Legs
chaeto- and solenidiotaxy given in Table 1.
Male, Larva, and Non-phoretic Female
unknown.
Etymology. The generic name refers to some simi-
larities with the genera Pygmephorellus and Pseudo-
pygmephorellus, and somewhat more derivative
characters than these two genera (“Meta” meaning
“after" þ Pygmephorellus).
Differential Diagnosis. Adult females of the new
genus are similar to genera Pygmephorellus Cross &
Moser, 1971 and Pseudopygmephorellus Khaustov,
2008 by the following characters. Gnathosomal capsule
dorsally with two pairs of setae; prodorsal shield with
three pairs of unmodified setae and one pair of capitate
trichobothria. Stigmata oval or round. Coxal fields I
with three pairs of setae, coxal fields II with two pairs
of setae, legs I four-segmented, with large sedentary
claw on massive tibiotarsus; seta d on femur I hooked.
The new genus differs from Pygmephorellus and Pseu-
dopygmephorellus by the absence of subcapitular setae
m (present in Pygmephorellus and Pseudopygmephorel-
lus), posterior margin of posterior sternal plate tripar-
tite (entire in Pygmephorellus and Pseudopygm
ephorellus), seta 1b bifurcate (not bifurcate in Pygme-
phorellus and Pseudopygmephorellus). The new genus
differs from Pygmephorellus by absence of setae l
00
on
genu II (present in Pygmephorellus).
Species Included. The new genus includes three
species: Metapygmephorellus colydius Rahiminejad &
Hajiqanbar sp. nov. (type species), M. orientalis Khaus-
tov sp. nov., and M. brachycercus (Cross & Moser,
1971)comb.nov.
Distribution and Habitat. All known species of
this new genus are associated with subcortical beetles.
M. colydius Rahiminejad & Hajiqanbar sp. nov. col-
lected from Colydium elongatum (F., 1787) and Dorcus
parallelipipedus (L., 1758) (Coleoptera: Zopheridae
and Lucanidae) in Iran; M. orientalis Khaustov sp. nov.
collected from the bark beetle Hylurgops interstitialis
Chapuis, 1875 (Col.: Curculionidae) from Far East
Russia, and M. brachycercus (Cross & Moser, 1971)
comb. nov. known from USA (Louisiana) where it was
collected under the bark of Pinus palustris infected
with Ips calligraphus (Germar, 1824), and the tenebrio-
nid beetle Corticeus glaber (LeConte, 1878), a subcort-
ical associate of pine bark beetles (Cross and Moser
1971).
Metapygmephorellus colydius Rahiminejad &
Hajiqanbar sp. nov.
(urn:lsid:zoobank.org:act:B30BFD64-EE82-4FC4-
8D7F-BAA3C2E28E50)
Diagnosis. The new species is distinguished by the
following character states: genu I with four setae; setae
c
1
and d not reaching to posterior borders of tergites C
and D, respectively; seta h
2
half as long as h
1
;setaeps
1-
3
pointed; seta 4a blunt-ended; setae pl
00
on tarsi II and
III modified, spine-like.
Adult Female. (Figs. 1–7). Length of idiosoma 193
(160–196), width 83 (81–97).
Gnathosoma: Length of gnathosomal capsule 22
(17–24), width 24 (18–28); cheliceral setae cha 6(5–8),
chb 5 (5–7), palpal dFe 4(4–6),dGe 4(3–7);pharyng-
eal system (Fig. 3) with three pumps, pump 1 smallest,
pump 2 largest and striated, pump 3 oval-shaped, diffi-
cult to discern.
Idiosomal dorsum (Fig. 1): Body oval, all tergites
well-sclerotized and punctate. Prodorsal shield with
smooth trichobothria. All dorsal setae smooth and
blunt-ended, except pointed c
2
.Setac
2
nearly two
times longer and placed on same transverse line with
894 A
NNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 108, no. 5
c
1
, seta c
1
not extending to posterior border of tergite
C, posterior border of tergite C slightly concave; setae
d not extending to posterior border of tergite D.
Lengths of dorsal setae: v
1
16 (15–19), v
2
15 (15–17),
sc
2
31 (25–35), c
1
18 (16–19), c
2
33 (28–35), d 21 (16–
21), e 14 (13–16), f 25 (22–27), h
1
24 (21–24), h
2
15
(12–15). Distances between dorsal setae: v
1
- v
1
9(8–
14), v
2
- v
2
16 (15–20), sc
2
-sc
2
15 (13–19), c
1
-c
1
25 (23–
26), c
1
-c
2
17 (11–22), d-d 33 (27–33), e-f 6 (5–8), f-f 32
(31–36), h
1
-h
1
21 (18–24), h
1
-h
2
8 (7–9).
Idiosomal venter (Fig. 2): All ventral plates smooth;
all ventral setae smooth. Posterior margin of aggenital
plate rounded. Lengths of ventral setae: 1a 10 (9–13),
1b 16 (14–18), 1c 15 (13–18), 2a 12 (10–14), 2c 19 (17–
21), 3a 11 (9–12), 3b 12 (10–13), 3c 19 (18–22), 4a 10
(7–11), 4b 12 (9–14), 4c 15 (12–17), ps
1
11 (8–13), ps
2
12 (9–13), ps
3
18 (14–21). Setae 2a,3b,3c,4a,and4c
needle-like. Anterior genital sclerite triangular, posterior
genital sclerite small, oval. Setae ps
1
-ps
3
blunt-ended.
Legs (Figs. 4–7): Leg I (Fig. 4). Thicker and longer
than other legs. Setal formula (number of solenidia in
parenthesis): Tr1–Fe4–Ge4–TiTa17 (þx
1
, x
2
, u
1
, u
2
).
Tibiotarsus I with thick and robust claw, with seven
blunt-ended eupathidial setae (p
0
, p
00
, tc
0
, tc
00
, ft
0
and
ft
00
), and eupathidium k placed near solenidion u
2
,sole-
nidion x
1
5(4–5),x
2
3(2–4),u
1
6 (5–6) and u
2
4(3–
4), all finger-shaped except x
2
, baculiform; genu
with seta v
00
shorter than others; femur with setae l
0
needle-like and shorter than others, seta d hook-like;
trochanter with one seta v
0
same form as l
0
on femur.
Leg II (Fig. 5). Setal formula: Tr1–Fe3–Ge2–
Ti4(þu)–Ta6(þx). Tarsus with sickle-like simple claws
Table 1. Leg chaeto- and solenidiotaxy of the genus Metapygmephorellus gen. nov. (adult phoretic females)
Segment Leg I Leg II Leg III Leg IV
No. of
setae
Name of
setae
No. of
setae
Name of
setae
No. of
setae
Name of
setae
No. of
setae
Name of
setae
Trochanter 1 v
0
1 v
0
1 v
0
1 v
0
Femur 4 l
0
, l
00
, d, v
00
3 l
0
, d, v
00
2 d, v
0
2 d, v
0
Genu 4 or 3 l
0
, l
00
, v
0
, v
00
2 l
0
, v
0
2 l
0
, v
0
1 v
0
Tibia 17(4) d, l
0
, l
00
, v
0
, v
00
, k, u
1
, u
2
4(1) d, l
0
, v
0
, v
00
u 4(1) d, l
0
, v
0
, v
00
, u 4(1) d, l
0
, v
0
, v
00
, u
Tarsus pl
0
, pl
00
, pv
0
, pv
00
, s, tc
0
,
tc
00
, p
0
, p
00
, ft
0
, ft
00
x
1
,
x
2
6(1) pl
00
, pv
0
, pv
00
, tc
0
,
tc
00
, u
0
, x
6 pl
00
, pv
0
, pv
00
, tc
0
,
tc
00
, u
0
6 pl
00
, pv
0
, pv
00
, tc
0
,
tc
00
, u
0
Figs. 1–3. Metapygmephorellus colydius Rahiminejad and Hajiqanbar sp. nov., female. (1) Body in dorsal view; (2) Body
in ventral view. Scale bar 50 mm. (3) Pharynx. Scale bar 20 mm.
September 2015 RAHIMINEJAD ET AL.: A NEW GENUS OF THE PYGMEPHORIDAE—2 NEW SPECIES 895
and empodium. Solenidion x 6 (5–6) finger-shaped,
seta pl
00
modified, spine-like, seta tc
0
longest on tarsus;
tibia with solenidion u 4 (2–5) finger-shaped, seta v
00
longer than others; genu with two setae l
0
and v
0
,setav
0
robust and barbed; femur with setae d, v
0
and l
0
,setad
barbed, seta l
0
needle-like; trochanter with seta v
0
shorter than v
0
on femur.
Leg III (Fig. 6). Setal formula: Tr1–Fe2–Ge2–
Ti4(þu)–Ta6. Tarsus with seta pl
00
modified, spine-
like, seta pv
00
and tc
0
subequal; tibia with solenidion u 4
(2–4) finger-shaped, seta v
00
longest on tibia; genu with
seta l
0
longer than v
0
; femur divided into basi- and
telofemur, telofemur with seta d longer than seta v
0
;
trochanter with seta v
0
, longer than seta v
0
on femur.
Leg IV (Fig. 7). Setal formula: Tr1–Fe2–Ge1–
Ti4(þu)–Ta6. Seta tc
0
whip-like and longest seta on the
legs; tibia with solenidion u 2 (1–2) finger-shaped; seta
v
0
longer than others; genu with one seta v
0
;femurdiv-
ided into basi- and telofemur, setae d and v
0
,barbed;
trochanter with seta v
0
as long as v
0
on femur.
Male and Larva. Unknown.
Type, Host, and Locality Data. Female holotype
(VR-20130609-1), Gorgan, Golestan province, northern
Iran, phoretic on Colydium elongatum (F.) (Coleoptera:
Tenebrionoidea: Zopheridae) attached to ventral
surface, captured by light trap from Alangdareh forest,
36.46
N, 54.27
E, altitude 450 m.a.s.l., 9-VI-2013,
coll. V. Rahiminejad; paratypes: 30 females, same data
as holotype; 10 females, northern Iran, Mazandaran
province, phoretic on Dorcus parallelipipedus (L.,
1758) (Coleoptera: Scarabaeoidea: Lucanidae), col-
lected directly by forceps from a rotten stump in
Abbas-Abad forests, 36
37
0
N, 51
06
0
E, alt. 401 m.
a.s.l., 19-VII-2014, coll. A. Katlav.
Type Depositories. Theholotypeisdepositedin
the Acarological Collection, Department of Entomol-
ogy, Faculty of Agriculture, Tarbiat Modares University,
Tehran, Iran and paratypes are deposited in the follow-
ing collections: U.S. National Museum of Natural His-
tory, Washington D.C., U.S.A.; Tyumen State
University, Tyumen, Russia; and Acarological Collec-
tion, Zoological Museum, College of Agriculture, Uni-
versity of Tehran, Karaj, Iran.
Etymology. The species epithet refers to the
generic name of one of the host beetles (Colydium).
Differential Diagnosis. The new species is most
similar to M. brachycercus (Cross & Moser, 1971)
comb. nov. by the presence of four setae on genu I but
differs by setae c
1
and f on the same longitudinal level
(setae f further apart than setae c
1
in M. brachycercus);
Figs. 4–5. Metapygmephorellus colydius Rahiminejad and Hajiqanbar sp. nov., female: (4) Leg I in dorsal view; (5) Leg II
in dorsal view. Scale bar 20 mm.
896 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 108, no. 5
setae e and f not reaching to posterior margin of the
body (setae e and f protruding beyond posterior margin
of the body in M. brachycercus); setae f and h
1
subeq-
ual (seta f shorter than h
1
in M. brachycercus); seta h
2
half as long as h
1
(seta h
2
longer than half of h
1
in M.
brachycercus); seta 1c about 1.5 times longer than 1a
(seta 1a and 1c subequal in M. brachycercus); seta ps
2
longer than ps
1
(seta ps
2
as long as ps
1
in M. brachycer-
cus); and seta 3c longer than 4b (setae 3c and 4b sub-
equal in M. brachycercus).
Metapygmephorellus orientalis Khaustov sp. nov.
(urn:lsid:zoobank.org:act:FC540221-3EC3-45FC-
910F-D406EB8CFE1C)
Diagnosis. The new species has the following char-
acter states: genu I with three setae; setae c
1
and d
extending to posterior border of tergites C and D,
respectively; seta h
2
longer than half of h
1
;setaeps
1-3
blunt-ended; seta pl
00
on tarsi II and III simple and
pointed.
Adult Female. (Figs. 8–13). Length of idiosoma
176, width 114.
Gnathosoma: Length of gnathosomal capsule 19,
width 21.
Spherical in shape; setae cha 11 pointed, chb 9
blunt-ended, palpal dFe 5 blunt-ended, dGe 9pointed,
postpalpal setae 4 needle-like. Pharyngeal system tri-
partite, difficult to discern.
Idiosomal dorsum (Fig. 8): Body elliptic, all tergites
punctate; stigmata oval; prodorsal shield with barbed
trichobothria. All dorsal setae weakly barbed and blunt-
ended, except pointed setae c
1
and h
2
. Posterior border
of tergite C slightly concave. Setae d extending to pos-
terior border of tergite. Cupules not evident. Lengths
of dorsal setae: v
1
21, v
2
25, sc
2
36, c
1
30, c
2
46, d 29, e
25, f 44, h
1
41, h
2
33. Distances between dorsal setae:
v
1
-v
1
11, v
2
-v
2
25, sc
2
-sc
2
27, c
1
-c
1
46, c
1
-c
2
15, d-d 53,
e-f 10, f-f 42, h
1
-h
1
21, h
1
-h
2
14.
Idiosomal venter (Fig. 9): Apodemes 1 and 2 strongly
developed and joined with appr. All ventral plates
smooth. All ventral setae smooth. Apodemes 3 weakly
developed. Apodemes 5 absent. Posterior margin of
aggenital plate rounded with short tongue-like elonga-
tion. Lengths of ventral setae: 1a 16, 1b 18, 1c 17, 2a
11, 2c 21, 3a 15, 3b 12, 3c 15, 4a 12, 4b 17, 4c 17, ps
1
5, ps
2
11, ps
3
24. Seta 2a,3a,3b, ps
1
-ps
3
blunt-ended.
Figs. 6–7. Metapygmephorellus colydius Rahiminejad and Hajiqanbar sp. nov., female: (6) Leg III in dorsal view; (7) Leg
IV in dorsal view. Scale bar 20 mm.
September 2015 RAHIMINEJAD ET AL.: A NEW GENUS OF THE PYGMEPHORIDAE—2 NEW SPECIES 897
Anterior genital sclerite very small, difficult to discern,
posterior genital sclerite oval.
Legs (Figs. 10–13): Leg chaetotaxy similar with that
of M. colydius Rahiminejad and Hajiqanbar sp. nov.,
but genu I with 3 setae (v
00
absent).
Leg I (Fig. 10). Thicker than other legs. Solenidia x
1
7, x
2
5, u
1
6, u
2
5, all finger-shaped except baculiform
u
2
; femur with setae v
00
longer than others, seta d
hook-like; seta v
0
of trochanter shortest on leg I.
Leg II (Fig. 11). Tarsus with sickle-like simple claws
and empodium. Solenidion x 5 finger-shaped, seta u
0
shortest on tarsus; tibia with solenidion u 4finger-
shaped; seta d of femur weakly barbed; trochanter with
seta v
0
longer than l
0
of femur.
Leg III (Fig. 12). Tarsus with seta u
0
shortest on leg;
tibia with solenidion u 3finger-shaped,setav
00
longest
on tibia; genu with seta v
0
longer than l
0
; femur divided
into basi- and telofemur, seta d of femur longer than
seta v
0
; trochanter with seta v
0
, longer than seta v
0
of
femur.
Leg IV (Fig. 13). Setae pv
0
barbed and shorter than
tc
00
; tibia with solenidion u 2finger-shaped;setav
0
barbed; seta v
0
of genu weakly barbed; femur divided
into basi- and telofemur, seta d of femur barbed and
longer than v
0
; trochanter with seta v
0
as long as v
0
of
femur.
Male and larva. Unknown.
Type, Host, and Locality Data. Female holotype:
slide MM280890, Russia, Primorsky Krai, Pidan moun-
tain, on the bark beetle Hylurgops interstitialis Cha-
puis, 1875 (Col.: Curculionidae: Scolytinae) under the
bark of Pinus koraiensis, 28-VIII-1990, coll. M.Y.
Mandelshtam.
Type Depositories. Theholotypeisdepositedin
the Tyumen State University Museum of Zoology, Tyu-
men, Russia.
Etymology. The name of a new species refers to
distribution at Far East region.
Differential Diagnosis. The new species can be
distinguished from two other species of the genus by
genu I with three setae (genu I with four setae in M.
colydius and M. brachycercus); seta pl
00
on tarsi II and
III simple and pointed (seta pl
00
on tarsi II and III
modified, spine-like in M. colydius and M. brachycer-
cus); setae c
1
and d extending to posterior border of
tergite C and D, respectively (setae c
1
and d not reach-
ing to posterior border of tergite C and D, respectively
in M. colydius and M. brachycercus); setae ps
1-3
blunt
ended (setae ps
1-3
pointed in M. colydius and M. bra-
chycercus). Also the new species can be separated from
M. brachycercus by setae c
1
and f on the same longitu-
dinal level (setae f further apart than setae c
1
in
Figs 8–9. Metapygmephorellus orientalis Khaustov sp. nov., female. (8) Body in dorsal view; (9) Body in ventral view.
Scale bar 50 mm.
898 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 108, no. 5
M. brachycercus); setae f and h
1
subequal (seta f
shorter than h
1
in M. brachycercus); seta ps
2
longer
than ps
1
(seta ps
2
as long as ps
1
in M. brachycercus).
Moreover, the new species differs from M. colydius by
seta f protruding beyond posterior margin of the body
(seta f not reaching to posterior margin of the body in
M. colydius); seta h
2
longer than half of h
1
(seta h
2
half
as long as h
1
in M. colydius); setae 1c and 1a subequal
(seta 1c about 1.5 times longer than 1a in M. colydius);
setae 3c and 4b subequal (seta 3c longer than 4b in M.
colydius).
Discussion
The newly described genus is characterized by sev-
eral apomorphic characters: subcapitular setae m
absent; two pairs of setae on coxisternal plate II (setae
2b absent); two setae on genu II (seta l
00
absent); seta d
on femur I hook-like; setae 1b bifurcate; tripartite pos-
terior margin of poststernal plate. The absence of sub-
capitular setae is a unique character which not
recorded in other genera of pygmephoroid mites. Pres-
ence of only two setae on genu II (l
00
absent) is
known in other pygmephorid genera such as
Pseudopygmephorellus,someNeositeroptes,and
Ultrasiteroptes. Also, hook-like seta d on femur I could
be found in most pygmephorid genera with four-
segmented leg I, such as Pseudopygmephorellus
Khaustov, 2008; Pygmephorellus Cross & Moser, 1971;
Parapediculaster Khaustov, 2015; Elattoma Mahunka,
1969; Brasilopsis Mahunka, 1975; Luciaphorus
Mahunka, 1981; Pygmephorus Kramer, 1877; Mesopo-
tamiophorus Sevastianov & Zahida Al Douri, 1991; and
Microdispodides Vitzthum, 1914. Smooth and bifur-
cated seta 1b represented in some early-derivative pyg-
mephorid genera: Siteroptes Amerling, 1861;
Parasiteroptes Livshits, Mitrofanov and Sharonov, 1986;
Sevastianoviella Livshits, Mitrofanov and Sharonov,
1986; Neositeroptes Livshits, Mitrofanov & Sharonov,
1986; Krczaldania Sasa, 1961; Ultrasiteroptes Livshits,
Mitrofanov & Sharonov, 1986; and Parapediculaster
Khaustov, 2015.InsomePygmephorus Kramer, 1877
setae 1b also bifurcate, but always distinctly barbed;
similar condition of seta 1b alsoknowninsomeneo-
pygmephorid mites (Kerdabania Khaustov, 2009; Pseu-
dopygmephorus Cross, 1965; Petalomium Cross, 1965).
Among the pygmephorid mites, the tripartite posterior
margin of the poststernal plate is known only in
Figs. 10–11. Metapygmephorellus orientalis Khaustov sp. nov., female: (10) Leg I in dorsal view; (11) Leg II in dorsal
view. Scale bar 20 mm.
September 2015 RAHIMINEJAD ET AL.: A NEW GENUS OF THE PYGMEPHORIDAE—2 NEW SPECIES 899
Pediculaster Vitzthum, 1931, Metasiteroptes Cross,
1965, and Mesopotamiophorus Sevastianov & Zahida
Al Douri, 1991, but character states for the poststernal
plate are unknown for many pygmephorid genera. A
similar partitioning in poststernal plate is found in Elat-
toma, but the posterior margin of poststernal plate is
divided into two parts overlapping each other, indicat-
ing this character state is convergent.
The new genus is also well separated ecologically.
Species of Metapygmephorellus inhabit subcortical gal-
leries of various beetles. Among pygmephorid mites
similar habitats have species from the genera Elattoma
Mahunka, 1969, Microdispodides Vitzthum, 1914, and
some Pediculaster Vitzthum, 1931 (Smiley and Moser
1976, 1984; Rahiminejad et al. 2011), but they clearly
differ from Metapygmephorellus Rahiminejad, Haji-
qanbar & Khaustov gen. nov. morphologically. Mem-
bers of the most morphologically similar genera
Pygmephorellus Cross & Moser, 1971 and Pseudopyg-
mephorellus Khaustov, 2008 are associated with dung
beetles or inhabit soil (Khaustov 2007, 2008a; Katlav
et al. 2015).
Key to Species of the Genus Metapygmephorellus
Rahiminejad, Hajiqanbar & Khaustov gen. nov.
(females)
1- Genu I with four setae; seta pl
00
on tarsi II and III
modified, spine-like; setae c
1
and d not reaching to
posterior border of tergites C and D, respectively;
setae ps
1-3
pointed ................................................... 2
– Genu I with three setae; seta pl
00
on tarsi II and III
simple and pointed; setae c
1
and d extending to pos-
terior border of tergites C and D, respectively; setae
ps
1-3
blunt ended .... M. orientalis Khaustov sp. nov.
Figs. 12–13. Metapygmephorellus orientalis Khaustov sp. nov., female: (12) Leg III in dorsal view; (13) Leg IV in dorsal
view. Scale bar 20 mm.
900 ANNALS OF THE ENTOMOLOGICAL SOCIETY OF AMERICA Vol. 108, no. 5
2- Setae f and h
1
subequal; seta 1c about 1.5 times lon-
ger than 1a; seta 3c longer than 4b; seta ps
2
longer
than ps
1
.....M. colydius Rahiminejad & Hajiqanbar
sp. nov.
– Seta f shorter than h
1
; setae 1c and 1a subequal;
setae 3c and 4b subequal; seta ps
2
as long as ps
1
.. M.
brachycercus (Cross & Moser, 1971) comb. nov.
Acknowledgments
We thank Dr. M.Y. Mandelshtam (St.-Petersburg, Russia)
for materials of mites from bark beetles and for identification
of bark beetles, and Dr. Alexander G. Kirejtshuk (Zoological
Institute, Academy of Sciences, St. Petersburg, Russia) for
identification of the host zopherid beetle. We express our sin-
cere thanks to Alihan Katlav for collecting parts of material.
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Received 30 April 2015; accepted 6 July 2015.
September 2015 RAHIMINEJAD ET AL.: A NEW GENUS OF THE PYGMEPHORIDAE—2 NEW SPECIES 901