Atopomelus megalotis, Bochkov, Andre V., Abramov, Alexei V. & Hugot, Jean-Pierre, 2011

Bochkov, Andre V., Abramov, Alexei V. & Hugot, Jean-Pierre, 2011, Five new species of fur mites (Acariformes: Sarcoptoidea) from small mammals in Laos, Zootaxa 2980, pp. 1-22 : 6-7

Atopomelus megalotis sp. n.

( Figs. 3–5, 12 A)

MALE (holotype, Figs. 3, 4 and 12 A). Body, 600 long (440–620 in 10 paratypes), 160 wide (160–220). Prescapular shield 120–140 long; postscapular shield 180–210 long, completely covered by transverse lines; hysteronotal shield 140–170 long, trapeziform, covered by tubercles in anterior third, pair of round weakly sclerotized patches near bases of setae d2 present. Opisthonotal surface behind hysteronotal shield tuberculate. Lateral unsclerotized parts of idiosoma between levels of legs II and III insertions covered by scales. Aedeagus about 4 times shorter than femur III. Opisthogaster posterior to level of ps3 setae covered by scales. Length of idiosomal setae: si 40–55, se 45–80, c2 60–65, c 3 30–35, cp 110–160, d1 50–80, d2 50–340, e1 180–220, h 1 8–10, h2 50–60, h3 180–230; length of setae e2 and f2 highly variable, 20–200 and 30–100, respectively. Leg III and IV 210–320 and 470–560 long, respectively. Trochanter IV with ventral and dorsal spurs, ventral spur fang-like shape, 48–57 long, with single apex ( Fig. 12 A); dorsal spur well developed, slightly shorter than ventral spur, situated in basal part of this segment. Femur and genu IV together 180–190 long, femur with 1 ventral spur, 5–10 long. Tibiotarsi III and IV without pretarsus, 70–90 and 185–200 long, respectively. Tarsus IV with single pointed apex. Seta d III subequal in length to respective tibiotarsus, excluding pretarsus.

FEMALE (10 paratypes, Fig. 5 ). Body 600–665 long, 150–170 wide. Prescapular shield 100–120 long; postscapular shield well developed, 80–100 long, covered by scale-like pattern, with posterior median incision 20–25 long. Hysteronotum covered medially by triangular scales; length and width of these scales subequal. Genital papillae contiguous. Genital valves separated from each other, each bearing setae 4b and g. Sclerotized areas of coxae IV fused in posterior part, and setae 4a situated on unpaired sclerotized plate. Basal cap of spermatheca globosely inflated. Legs III and IV 120–140 long; tibiotarsi III and IV, excluding pretarsus, 50–60 long. Setae d III and IV subequal in length to respective tibiotarsi, excluding pretarsi.

Type material. Male holotype (T-At-ZISP AVB 09-0805-008), 7 male and 8 female paratypes (ZISP-At AVB 09-0805-006, # 1-15) from Hylomys megalotis Jenkins and Robinson ( Erinaceomorpha : Erinaceidae ), 14 November 2008, coll. A. Abramov, A. Tikhonov (field number #AA, AT 85); 2 male and 3 female paratypes (ZISP-At AVB 09-0805-002, #1-5), same locality, 9 November 2008 (#AA AT 23); 1 male paratype (ZISP-At AVB 09-0805- 0 10, #1), same data (#AA AT 10); 2 male and 3 female paratypes (ZISP-At AVB 09-0805-005, #1-5), same locality, 13 November 2008 (#AA AT 57); 3 male and 1 female paratypes (ZISP-At AVB 09-0805-006, #1-4), same data (#AA AT 56); 1 male and 1 female paratypes (ZISP-At AVB 09-0805-001, #1-2), same locality, 14 November 2008 (#AA AT 72); 1 male and 2 female paratypes (ZISP-At AVB 09-0805-004, #1-3), same data (#AA AT 70); 3 male paratypes (ZISP-At AVB 09-0805-007, #1-3), same data (#AA AT 71); 1 female paratype (ZISP-At AVB 09-0805- 009), same locality, 15 November 2008 (#AA AT 87); 1 male paratype (ZISP-At AVB 09-0805-003), same locality, 16 November 2008 (#AA AT 103). Numerous immature mite specimens from all these records are preserved in alcohol.

Type deposition. Holotype and most part of paratypes—ZISP, 1 male and 1 female paratypes—in UMMZ, 1 male and 1 female paratypes—MNHN, 1 male and 1 female paratypes—IRSNB.

Differential diagnosis. This new species belongs to the locusta group including three species. In males of this group, the postscapular shield has transverse lines, the opisthonotum posterior to the hysteronotal shield bears tubercles, and trochanter IV bears a dorsal spur; in females, the hysteronotum is covered medially by the triangular scales which are not longer than wide, the genital papillae are contiguous, and the basal cap of the spermatheca is inflated (Bochkov et al. 2005). Among members of this group, the new species is very close to Atopomelus locusta Trouessart from Neotetracus sinensis Trouessart and Hylomys suillus Muller from China, Vietnam, Laos, and Malaysia (Bochkov et al. 2005). In males of both mite species, the aedeagus is 3–4 times shorter than femur III, seta d III is subequal in length to the respective tibiotarsus, the dorsal and ventral spurs of trochanter IV are subequal, the hysteronotal shield is ornamented, the dorsal spur of trochanter IV situates basally, and femurogenu IV bears a single ventral spur; in females, setae d III and IV are subequal in the length to the respective tibiotarsi, the genital valves are separated from each other, and the distal part of the spermatheca is globose. These species differ from each other by the following feature. In males of Atopomelus megalotis sp. n., the ventral spur of trochanter IV is 48–57 long, fang-like ( Fig. 12 A), the opisthogaster anterior to level of setae ps3 is devoid of scales; in females, the width and length of the median scales of the hysteronotum is subequal. In males of A. locusta , the ventral spur of trochanter IV is 27–30 long, spade-like ( Fig. 12 B), the opisthogaster anterior to level of setae ps3 bears scales; in females, the median scales of the hysteronotum are distinctly wider than their length.

Etymology. The specific epithet derives from the specific name of the host and is a noun in apposition.

Remarks. It is interesting that newly described A. megalotis is morphologically very close to A. locusta parasitizing the two gymnure species, Neotetracus sinensis and Hylomys suillus (Bochkov et al. 2005) . Neotetracus sinensis is also parasitized by one more Atopomelus species, A. priapus Bochkov et al. The presence of two so closely related species A. locusta and A. megalotis on N. sinensis and H. megalotis , respectively, could be explained by phylogenetic links between these hosts or by the transfer of their parasites from one host species to another with the following speciation. Hylomys megalotis is a very peculiar host and its phylogenetic relationships are not yet clear; therefore, it was only temporarily placed in the genus Hylomys ( Jenkins & Robinson 2002) . However, there are no data supporting its sister grouping with N. sinensis . On another hand, the ranges of these hosts, at least in the present time, are distant from each other and, therefore, the hypothesis suggesting host switching between them is highly improbable. We believe that N. sinensis is the initial host only for A. priapus . Ranges of H. suillus and N. sinensis are partially overlapping which makes the transfer of A. locusta from H. suillus to N. sinensis feasible. Whereas H. megalotis , probably, received mites directly from H. suillus (ranges of these hosts are also overlapping) or A. megalotis and A. locusta originated from the common ancestor, which parasitized ancestor of the genus Hylomys . This hypothesis not only explains the presence of two Atopomelus spp. on N. sinensis (each gymnure species being associated with one species from this genus, only) but also gives evidence for sister relationships between A. locusta and A. megalotis .

Figures

FIGURE 4. Atopomelus megalotis sp. n., male holotype in ventral view.

FIGURE 5. Atopomelus megalotis sp. n., female: A—Propodonotum in ventral view; B—Posterior end of idiosoma in lateral view; C—Median scales of hysterosoma; D—Vulva; E—Posterior part of coxal fields IV; F—Distal part of spermatheca; G— Tarsus III in ventral view. Scale bars: 100 μm = A, B; 50 μm = D, E; 25 μm = C, F, G.

FIGURE 12. A—Ventral spur of male trochanter IV of Atopomelus megalotis sp. n.; B—Same, Atopomelus locusta Trouessart; C— Hylomys megalotis Jenkins and Robinson (photo by Alexei V. Abramov); D— Laonastes aenigmamus Jenkins et al. at the hands of Alexei V. Abramov (photo by Alexey N. Tikhonov); E— Menetes berdmorei (Blyth) (photo by Alexei V. Abramov).