Review of the genus Myrmozercon Berlese (Acari: Laelapidae), with description of a new species from Iran
Author
Joharchi, Omid
Author
Babaeian, Esmaeil
Author
Seeman, Owen D.
text
Zootaxa
2015
3955
4
549
560
journal article
10.11646/zootaxa.3955.4.6
18afdd21-843f-40f1-8b03-f845e10768d4
1175-5326
241204
E544637B-924B-4A0A-A1D6-DDA5DEE9B2B4
Myrmozercon hunteri
sp. nov.
(
Figs 1–10
)
Specimens examined.
Holotype
, female,
Iran
, Alborz province, Savojbolagh, Khoznan, 36˚71' N, 50˚32' E, alt.
1595 m
,
15 August 2013
,
O
. Joharchi coll., clinging to the abdomen of soldiers of
Myrmica
sp. (
Formicidae
) (in JAZM).
Paratype
, one female, same data as
holotype
(in YIAU). (Host ants are also in YIAU).
Diagnosis
. Dorsal shield reticulate, with 27–33 pairs setae, length 83–103; some dorsocentral setae in
j -J
series lacking; posterior margin of shield rounded, not truncated; soft cuticle posterior to shield hypertrichous. Sternal shield essentially normal, posterior margin eroded slightly; setae
st4
present; genital shield elongate, reticulate, bearing setae
st5
only; metapodal shields absent; anal shield triangular, without anterolateral extensions. Palp setal count (trochanter to tibia)
1-5-6-12
; subcapitular groove with 11 rows of denticles, with 10–15 denticles per row; palp coxal seta present. Chelicerae with movable digit membranous, edentate, and fixed digit reduced, thin, edentate. Legs long, leg I longer (
1280–1283
) than all other legs (leg II 711–720; leg III 975–994; leg IV
1100– 1114
); setal counts (coxa to tibia) for legs I–IV:
2-5-14-13-10
,
2-5-11-11-10
,
2-5-7-11
-10,
1
-5-7-11-10; many leg setae spatulate.
Description.
Female. Dorsal idiosoma (
Fig. 1
). Length 890 (900), width 830 (835). Dorsal shield length 840 (846), width 703 (710), broadly oval, reticulate; shield tapers gradually to a broad point, not covering entire idiosoma, leaving unsclerotised cuticle surrounding dorsal shield; dorsal shield with at least 27 pairs of setae (lateral margins capturing six additional setae on left-hand side in
holotype
), setae long (83–103), almost all setae distinctly serrate in apical third, except
j1
,
z1
smooth. Pronotal part of dorsal shield holotrichous or slightly hypotrichous, setae in
z
- and
s
-series displaced laterally or lacking; opisthonotal part of dorsal shield hypotrichous, lacking anterior
J
-setae, setae in
Z
and
S
series lacking or displaced laterally; soft cuticle of opisthosoma hypertrichous. Muscle insertions prominent as desclerotised circular patches. Shield with 11 pairs of pore-like structures; lyrifissures near base of
j1
large and slit-like.
Ventral idiosoma
(
Fig. 2
). Tritosternum with short, broad, free base 30 (32) long and paired smooth, strap-like laciniae 152 (155) long (
Fig. 2
). Pre-sternal shields absent. Sternal shield length 149 (153), narrowest between coxae II 195 (198), widest between coxae II and III 343 (347), with biconvex anterior margin; posterior margin irregularly concave; shield bearing three pairs of small pointed setae (
st1
16,
st2
15,
st3
15) and two pairs of lyrifissures, lyrifissures
iv1
adjacent to setae
st1
, lyrifissures
iv2
between
st2
and
st3
; surface with indistinct linear ornamentation and weak transverse lines near anterior margin, central area smooth. Metasternal platelets absent, metasternal setae
st4
16 (17) and metasternal pores
iv3
located in soft cuticle; endopodal plates II/III fused to sternal shield, endopodal plates III/IV elongate, narrow, and free. Genital shield broad, rounded posteriorly, extending almost to anal shield; surface reticulate; genital setae
st5
14 (15) (right side on soft skin in
holotype
); length 398 (408), maximum width 250 (257) at level of setae
st5
; shield flanked by two pairs of irregular platelets. Paragenital pores absent. Anal shield subtriangular, length 92 (98), width 164 (173), its anterior half with lineate ornamentation; bearing longer post-anal seta 58 (60), and a pair of para-anal setae 48 (50); all anal setae blunt, thickened. Anal pores absent, cribrum a narrow band without discernible rows. Opisthogastric cuticle hypertrichous, anal shield flanked by a pair of long narrow platelets 74 (79), all pores absent. Peritreme short, extending from coxa IV to anterior margin of coxa III. Lyrifissure near stigmata and post-stigmatal plate and pores absent.
Gnathosoma
. Subcapitular groove with 14 rows of denticles, 10 to 15 very fine denticles per row, denticles more distinct in central rows and indistinct in anterior and posterior rows (
Fig. 3
). Hypostome with three pairs of setae, internal posterior hypostomal setae
h3
longest; surface of subcapitulum ornamented with transverse and curved lines (
Fig. 3
). Palp coxal setae two-tined. Epistome triangular, smooth, with pointed apex (
Fig. 4
). Palp setal counts: trochanter 1, femur 5, genu 6, tibia 12; all palp setae pointed; palp apotele two-tined (
Fig. 5
), dorsodistal edge of palp femur with low swelling. Chelicera hyaline, fixed digit of chelicera reduced and edentate, pilus dentilis absent, cheliceral seta fine, prostrate (
Fig. 6
); movable digit edentate, arthrodial membrane with a rounded flap and a few short filaments (
Fig. 6
). Corniculi short, broad, weakly sclerotised. Internal malae separate (pushed to left side on illustration), fine and pointed, smooth, although
paratype
with few denticles. Lateral malae arms absent (
Fig. 3
).
Legs
. Legs (
Figs 7–10
). Length of leg
I 1280
(1283), leg II 711 (720), leg III 975 (994), leg
IV 1100
(1114). Setal counts for legs I–IV (coxa to tibia):
2-5-14-13-10
,
2-5-11-11-10
,
2-5-7-11
-10,
1
-5-8-11-10. Chaetotaxy (both sides examined): Leg I: coxa 0 0/1 0/1 0, trochanter 1 0/1 0/2 1, femur 2 3/2 3/2 2, genu 2 3/2 3/1 2, tibia 2 2/2 1/1 2 (
Figure. 7
). Leg II: coxa 0 0/1 0/1 0, trochanter 1 0/1 0/2 1, femur 2 3/1 2/2 1, genu 2 2/1 3/1 2, tibia 2 2/1 2/1 2 (
Fig. 8
). Leg III: coxa 0 0/1 0/1 0, trochanter 1 0/1 0/2 1, femur 2 2/0 1/1 1, genu 2 3/1 2/1 2, tibia 2 3/1 1/1 2 (
Fig. 9
). Leg IV: coxa 0 0/1 0/0 0, trochanter 1 0/1 0/2 1, femur 1 2/2 2/1 0, genu 2 2/1 3/1 2, tibia 2 1/1 3/1 2; almost all setae with club-like tip. Tarsi II-IV with 18 setae 3 3/2 3/2 3 + mv, md. All pre-tarsi with a pair of thin claws and a membranous ambulacrum.
Etymology.
This species is named in honour of Preston E. Hunter, who did important early work on these mites.
Notes
. The new species is unique within
Myrmozercon
because of its numerous club-tipped leg setae and its leg setal count, especially leg I. Leg setation varies considerably within the genus, but if femur and genu I have 13– 16 setae, then tibia I usually has 13–16 setae. The new species has 14 and 13 setae on femur and genu I, respectively, but only 10 setae on tibia I. The only species that shares a similar leg setal count is
M
.
iainkayi
which has 13 and 12 setae on femur and genu I, respectively, but 10 setae on tibia I.
The presence of 14 setae on tibia I is only known in three other species:
Myrmozercon burwelli
Shaw & Seeman, 2009
,
M
.
flexuosa
(
Michael, 1891
)
and some specimens of
M
.
rotundiscutum
Rosario & Hunter, 1988
, which has 13 or 14 setae. However, these are not the same setae, emphasising the importance of providing full setation. In
M
.
burwelli
and
M
.
flexuosa
, these species have two
pd
and three
pv
setae (i.e. 2 3/2 2/3 2) while
M
.
rotundiscutum
and the new species has three
pd
and two
pv
setae (i.e. 2 3/2 3/2 2).
In all other features the new species is closest to
M
.
rotundiscutum
in having very long legs I, lacking some of the
J
-series setae, being hypertrichous around the idiosomal margins, sharing a similar-shaped genital shield, and a similar body size. It is distinguished from this species by its palp and leg setal counts, simple palp coxal seta, and acuminate leg setae.