Acariform mites (Acariformes) - permanent symbionts of Hapalomysdelacouri Thomas (Rodentia, Muridae) in Vietnam.

Two new species of parasitic acariform mites (Acariformes) are described from the Delacour's marmoset rat Hapalomysdelacouri Thomas (Rodentia: Muridae) in Vietnam: Afrolistrophorus (Afrolistrophorus) hapalomyssp. n. (Listrophoridae) and Radfordia (Radfordia) mirabilissp. n. (Myobiidae). Based on morphological evidences, we show that species of both mite genera associated with Hapalomys Blyth do not demonstrate clear phylogenetic links with respective congeners from rodents of the closest genus Chiropodomys Peters (Rodentia: Muridae).

Introduction

Marmoset rats of the genus PageBreak Blyth (: : ) are medium-sized arboreal from Southeast Asia, with highly patchy distributions throughout their range from southern China to the Malay Peninsula. The genus consists of two species, Thomas and Blyth (Musser 1972, Musser and Carleton 2005). Little is known about the life history of marmoset rats because of paucity of museum materials available for study. Parasitic mites of marmoset rats have never been reported.

Several specimens of the Delacour’s marmoset rat were collected in southern Vietnam during the mammalogical surveys carried out by the Joint Vietnamese-Russian Tropical Research and Technological Centre (Abramov et al. 2012). In this paper, we describe two new mite species belonging to the families and () collected from this host. Mites of both families are represented by permanent and highly specialized mono- or stenoxenous ectoparasites inhabiting the fur () and skin () of mammals (Bochkov 2009, 2010).

Material and methods

In the field, the trapped hosts were individually wrapped in cheesecloth to prevent falling-out of ectoparasites and preserved in 70% ethanol. In the laboratory conditions, mites were collected from ethanol preserved hosts with fine forceps under dissection microscope and mounted in Hoyer’s medium. Specimens were studied using a Leica microscope under phase contrast and Nomarsky (DIC) optics. Drawings were made with a camera lucida, and measurements were taken using a calibrated ocular micrometer. In the descriptions below, the idiosomal setation of listrophorid mites follows Griffiths et al. (1990) with modifications by Norton (1998) concerning coxal setae; the leg setation follows Grandjean (1939a). The idiosomal setation of myobiid mites follows Grandjean (1939b) as interpreted by Bochkov et al. (2008). All measurements are in micrometres (μm), provided for paratypes in parentheses, and were taken as follow: body length = the total length from the anterior extremity of the prescapular shield in listrophorids or the palpal extremites in myobiids to the posterior border of the body; body width = width at the level of setae se in listrophorids and setae c2 in myobiids; length of dorsal shields(listrophorids) = maximum length, measured along the median line of the shields; length of opisthosoma (listrophorids) = length from the posterior margins of trochanter IV insertions to the posterior border of the opisthosoma; length of the posterior legs (listrophorids) = length from the most basal point of the trochanter to the apex of the tarsus, excluding pretarsus; tarsal length was measured without pretarsus. Host systematics follows Musser and Carleton (2005).

Abbreviations of institutions:

UMMZ;

University of Michigan Museum of Zoology, Ann Arbor, USA

ZISP.

Zoological Institute of the Russian Academy of Sciences, St. Petersburg, Russia

Systematics

Family Megnin & Trouessart Genus Fain Subgenus Fain

Bochkov & Abramov sp. n.

http://zoobank.org/8AADCBF1-40F9-4A00-9DB6-6ACDEFC2F49B

Figs 1 , 2

Figure 1.

sp. n., male holotype, A dorsal view B ventral view C tarsus III in ventral view D tarsus IV ventral view. Scale bars: A and B = 50 μm; C and D = 25 μm.

Figure 2.

sp. n., female, A lateral view B opisthosoma in dorsal view C ovipore D tibia and tarsus III in ventral view. Scale bars: A and B = 100 μm; C and D = 50 μm.

Type material.

Male holotype (ZISP L-T-9, AVB 10-0803-012), 7 male and 12 female paratypes (ZISP AVB 10-0803-012, 1-19) from Thomas (: ) [fur], VIETNAM: Binh Phuoc Province, Bu Gia Map National Park, 13 km NE Bu Gia Map Village, 540 m a.l.s., 12°11'37"N, 107°12'21"E, 13 January 2010, coll. A.V. Abramov (ZISP 99485). Mites removed by A.V. Bochkov.

Type deposition.

Holotype and 17 paratypes deposited in ZISP, one female and one male paratypes in UMMZ.

Description.

Male (holotype; paratypes = 7; Fig. 1). Body 360 long (350–385), 105 wide (100–110). Prescapular shield 110 long (105–110) with distinct median process. Postscapular shield 62 long (62-65), covered by 8-10 transverse markings; 2 anterior markings interrupted in median part. Median apodeme present. Hysteronotal shield 155 long (150–160), completely covered by few distinct striae from anterior margin to level of setal bases e2; these striae transverse in anterior one third of shield, oblique in middle, and almost longitudinal in posterior one third. Supranal concavity completely sclerotized. Shortest distance between postscapular and hysteronotal shields 10 (10–25). Setae h2 155 long (140–160); membranous setae h3 well developed, about 35 wide, slightly overlapping, without ribs. Terminal cleft 30 long (30–37). Opisthosomal lobes about 20 maximum wide. Cuticle between coxal fields II not striated. Coxal apodemes III fused to each other. Aedeagus about 45 long. Diameter of adanal suckers about 8. Legs III and IV about 75 and 90 long, respectively. Tarsus III without dorso-subapical projection. Tarsi III 20 long (20–23) and tarsi IV 25 long (25–30). All setae of tarsi III and IV shorter than respective segments, excluding pretarsi; setae d III and d IV spur-like, setae e IV microspines. Solenidia ω1 I, II 12–15 long, ω3 I about 25 long, φ I, II 40–45 long.

Female (ranges for 10 paratypes, Fig. 2). Body 425–440 long, 100–115 wide. Prescapular shield 110–120 long. Anterior margin of prescapular shield with distinct median process. Postscapular shield about 75 long, covered by 7-9 transverse markings. Median apodeme present. Idiosomal surface between postscapular and hysteronotal shields with 3–4 transverse lines. Hysteronotal shield 70–80 long, crossed by 8–11 oblique striae, 3 posterior striae very short, situated medially. Hysteronotum posterior to hysteronotal shield with 18–20 transverse striae, sclerotized, but less than this shield properly. Opisthosoma about 180 long. Posterior end of opisthonotum without lateral sclerotized patches. Cuticle between coxal fields II not striated. Opisthogaster without scales or verrucae. Setae h2 short, about 8 long, subequal in length to other opisthosomal setae. Setae ps1, ps2, and 4b absent. Legs III and IV subequal, 65–70 long. Setae d III and d IV about 2 times shorter than respective tarsi, excluding pretarsus. Solenidia ω1 I, II about 12 long, ω3 I about 24 long, φ I, II about 8 long.

Etymology.

The species name is derived from the generic name of the host and is a noun in apposition.

Differential diagnosis.

This new species belongs to the “apodemi” species group, which includes twelve species parasitizing mostly Eurasian murines (). All species in this group have a median process on the anterior margin of the prescapular shield. In males, apodemes III are fused to each other; in females, the cuticle between coxal fields II is without distinct striations, setae ps1 and ps2 are either present or absent, setae h2 are not longer than other opisthosomal setae (Bochkov and OConnor 2006; Bochkov et al. 2011). Among species of the “apodemi” group, the new species is close to Bochkov et al., 2011 from Jenkins et al. (: ) (Bochkov et al. 2011). In both species, the postscapular shield is distinctly developed and possesses several transverse markings and lacks a median sclerotized band; seta d III is much shorter than the respective tarsus (excluding the pretarsus); in males, the hysteronotal shield is ornamented in posterior part, setae h3 are strongly widened and slightly overlap each other; in females, setae 4b, ps1 and ps2 are absent, the ventral side of opisthosoma has no verrucae or scales. sp. n. differs from by the following characters. In both sexes of , the postscapular and hysteronotal shields are covered by a few markings or striae (less than 15), setae d IV of tarsi IV are at least twice as short as the respective segment; in males, the supranal concavity is completely sclerotized, tarsi IV are without projections; in females, most striae of the hysteronotal shield are oblique, the posterior end of the opisthonotum is devoid of the lateral sclerotized patches. In both sexes of , the postscapular and hysteronotal shields are covered by numerous markings or striae (more than 20), setae d IV of tarsi IV are subequal or longer than the respective segment; in males, the supranal concavity is not sclerotized, tarsi IV have a distinct subapical projection; in females, striae of the hysteronotal shield are relatively straight, the posterior end of the opisthonotum has a pair of the lateral sclerotized patches.

Family Megnin Genus Ewing Subgenus Ewing

Bochkov & Abramov sp. n.

http://zoobank.org/0B4528B8-9C9B-4C20-8FF3-558911D7363F

Fig. 3

Figure 3.

sp. n., female holotype, A dorsal view B ventral view C vulva. Scale bars: A and B = 100 μm; C = 50 μm.

Female holotype (ZISP My-T-37, AVB 10-0803-012) and 1 female paratype (ZISP AVB 10-0803-012) from Thomas (: ) [skin], VIETNAM: Binh Phuoc Province, Bu Gia Map National Park, 13 km NE Bu Gia Map Village, 540 m a.l.s., 12°11'37"N, 107°12'21"E, 13 January 2010, coll. A.V. Abramov (ZISP 99485). Mites removed by A.V. Bochkov.

Holotype and single paratype deposited in ZISP.

Female (holotype, 1 paratype). Body 435 long (410), 245 wide (230). Body 1.8 times longer than wide. Setae PageBreakvi, ve, d1, and d2 10–12 wide at base; si and se2 about 7 wide at base; c1 and c2 about 5 wide at base, e1, e2, and f2 about 3 wide at base. Apices of setae si reaching level of setal bases d1, apices of setae se reaching level of setal bases c2. Approximate distances between bases of setae: vi–vi 25, si–si 22, c1–c1 17, c1–c2 50, d1–d1 15, d2–d2 50, c1–d1 52, d1–d2 17. Setal bases f1 situated close to e2 than to e1, distance e1–f1 about 50, f1–e2 about 13. Setae f2 situated at lateral margins of idiosoma. Lengths of setae: vi 75 (70), ve 90 (93), si 115 (110), se 87 (85), c1 63 (75), c2 125 (115) – all distinctly longitudinally striated; d1 115 (117) and d2 about 125, membranous, without striae, e1 about 27, e2 about 75, f1 about 60, f2 about 15, h1 about 12, h2 310 (315), ps1 and ps2 about 11, ps3 (hook-like) about 15, g1 about 6, g2 about 8, 1a, 2a 25–28, 3a about 80, and 4a about 75, ag1 and ag3 8–11, ag2 about 12. Setae 3a and 4a slightly thickened. Apical segment of leg I without ventral projection. Setation for legs II-IV (solenidia in parentheses): tarsi 7(1)-6-6, tibiae 6-6-6, genua 7 (1)-6-5, femora 5-3-3, trochanters 3-3-3, coxae 4-2-2.

This epithet refers the unusual external morphology of this species – mirabilis (Latin, wonderful).

The subgenus is separated onto two species groups, “” (setation of coxae II-IV 3-2-2) and “lancearia” (3-1-2) (Bochkov and Fain 2003; Bochkov 2009). The new species distinctly differs from all known species of both groups by the setation of coxae II-IV(4-2-2), position of setae f2 on the lateral margins of the opisthosoma (vs. distant from the lateral margins in all other species) and the bases of f1 and e2 which are situated close to each other (vs. distant in all other species). Therefore, we establish for this new species a new species group mirabilis.

Discussion

The phylogenetic position of is still unclear because of the scarcity of museum specimens. Usually the genus is placed within division of the large muroid subfamily (Musser and Carleton 2005). Other authors suggested a close link between and (Misonne 1969; Musser and Newcomb 1983; Chaimanee 1998; Musser and Carleton 2005). The both mite species from described herein strongly differ from the respective congeners described from rodents of the genus Peters (Fain 1970, 1976; Bochkov and Fain 2003). Fain, 1970 described from Thomas and sp. n. belongs to the same species group “apodemi” but in the limits of this group they strongly differ from each other by the ornamentation of the dorsal shields in both sexes. Fain, 1976 described from (Blyth) is the typical representative of the species group “” (Bochkov and Fain 2003), whereas sp. n. is a sole representative of a separate species group and morphology strongly different from all other representatives of this subgenus (see description). Based on morphological evidences, we conclude that species of both mite genera associated with Blyth do not demonstrate clear phylogenetic links with respective congeners from rodents of the closest genus .