Demodex midae, Tokiwa & Ueda & Watanabe & Chou & Ozaki, 2024

Tokiwa, Toshihiro, Ueda, Kengo, Watanabe, Nagi, Chou, Shyun & Ozaki, Kiyokazu, 2024, A new species of Demodex (Acari: Demodecidae) from the skin of golden-handed tamarins, Saguinus midas (Primates: Cebidae), International Journal for Parasitology: Parasites and Wildlife 23, pp. 100920-100920 : 100920-

Genus Demodex Owen, 1853

Demodex midae n. sp.

Male (n = 9 and a holotype) ( Fig. 3A–F ): Slender body, highly elongated; body length [Holotype = 146.5] 154.3 ± 6.9 (139.0–160.9); body length to width ratio [4.4] 5.1 ± 0.5 (4.4–5.9). Gnathosoma trapezoidal in outline; [16.2] 17.1 ± 0.9 (16.0–19.2) long and [20.4] 19.5 ± 1.2 (16.8–20.8) wide. Terminal-free segment of palp with two large, conical spines and 2 min, conical spines ( Fig. 3A and C ). Supracoxal spines (setae elc.p) ( Fig. 3B and D ), ca. [2.2] 2.3 (2.1–3.3) long, spaced [11.8] 11.6 ± 0.3 (11.0–12.0) apart; each spine bends in the midline. Subgnathosomal setae (setae n) [ Fig. 3A ] as faint dots lateral to the central margin of the horseshoe-shaped pharyngeal bulb and spaced

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[3.5] 3.7 ± 0.4 (3.2–4.3) apart. Podosoma rectangular; [50.4] 51.6 ± 0.7 (50.4–52.5) long and [33.1] 30.4 ± 2.7 (25.4–33.5) wide; four pairs of five segmented short legs, with coxa integrated into ventral idiosomal wall; small interspaces separate epimeral plates (coxal fields) in the midline and aligned; pair coxa I triangular, and pairs II, III and VI trapezoidal. Tibiotarsus of each leg with a pair of forked claws ( Fig. 3E ), c.a. [2.0] (1.8–2.1), with large spur, and two knobs. Tarsus I and II, each with a minute dorsal solenidion. Aedeagus tubular ( Fig. 3F ), [8.5] 8.5 ± 0.7 (8.0–9.9) long, pointed apically with bulbous apical; genital opening on the dorsum at the level of the posterior margin of coxa I. Prodosal tubercles arranged in trapezoidal: interspace of first pairs [16.9] 16.8 ± 1.3 (15.0–19.5) long, of second pair [12.9] 15.4 ± 2.5 (12.0–19.8) long, distance between pairs [9.1] 8.5 ± 0.7 (7.8–9.5). Opisthosoma tubular, gradually tapered toward the end; [79.9] 85.5 ± 5.7 (73.0–91.0) long, represents [55%] 54% (52–57%) of the body. Opisthosoma distinctly annulated; annulations along its entire length on the dorsal side, but along its the posterior three-quarters to four-fifths on ventral side. Opisthosomal organs are absent.

Female (n = 14) ( Fig. 3G ): Slender body, highly elongated; body length 166.5 ± 21.3 (136.9–210.7); body length to width ratio 5.7 ± 1.1 (4.2–8.0). Gnathosoma as in male; 17.4 ± 1.4 (15.2–20.1) long and 20.2 ± 1.5 (16.5–22.1) width. Supracoxal setae (setae elc.p) as in male; spaced 12.1 ± 0.5 (11.6–12.7) apart. Subgnathosomal setae (setae n) as in male; spaced 4.7 ± 0.4 (4.2–5.2). Podosoma as in male; 52.6 ± 3.8 (43.3–58.9) long and 29.5 ± 2.9 (24.8–33.5). Prodorsal tubercles arranged tetrazoidal: interspace of fast pairs 20.2 ± 0.4 (19.7–20.7) long, of second pairs 22.5 ± 0.8 (21.4–23.6) long. Vulva a longitudinal slit, 4.7 ± 0.4 (4.2–5.2) long, anterior limit commences just behind the median confluence of coxal plates IV. Opisthosoma as in male; 96.3 ± 19.5 (67.3–133.2) long, constitutes 57% (48–65%) of body length. Opisthosoma distinctly annulated; annulations along its entire length on the dorsal side, but along its the posterior two-thirds on ventral side. The pore of the linear opisthosomal organ, located in the posterior part of the opisthosoma, is long anterior to the opisthosomal terminus.

Egg (n = 15) ( Fig. 3H ): Spindle-shaped with asymmetry in the major axis and bluntly rounded ends; 77.5 ± 3.1 (72.7–83.6) long and 24.0 ± 1.2 (21.3–25.2) wide. The chorion smooth; without operculum.

Type host: Saguinus midas L., 1758 (Primates: Cebidae ).

Habitat: Hair follicles on the face of the host. Other body parts were not examined.

Etymology: The specific epithet “ midae ” is adopted from the specific name of the type host.

Material deposited: The slides containing holotype male ( MPM Coll. No. 25276) and paratypes ( MPM Coll. No. 25277) were deposited in the Meguro Parasitological Museum , Meguro , Tokyo, Japan. Representative sequences were deposited in the DNA Data Bank of Japan (18S: accession nos. LC796752; 16S: accession no. LC796753) .

ZooBank registration number: 7B16AD86-C203-45FE-B70C- B95BAA8022DB.

Remarks: Demodex midae n. sp. from golden-handed tamarins is morphologically most similar to D. macaci from the rhesus monkey ( Macaca mulatta ) ( Karjala et al., 2005). However, total length of female and aedeagus of male of D. midae n. sp. are shorter than those of D. macaci ( Table 3). Demodex midae n. sp. has two large and two small spines on the palp, while D. macaci has four small spines. Male genital opening on the dorsum at the level of the posterior margin of legs I in D. midae n. sp., while in D. macaci it on anterior margin of legs II.

Figures

Fig. 3. Demodex midae n. sp. (A) Holotype male, ventral view. (B) Holotype male, dorsal view. (C) Spines on the right palpus, male, ventral view. (D) Supracoxal spine, male, dorsal view, arrows indicate the orientation of the left spine as a view on the gnathosoma. (E) Claw on the leg of tarsi, male. (F) Aedeagus. (G) Female, ventral view. (H) Egg. ae: aedeagus, op: opisthosomal organ, sg: subgnathosomal setae (setae n), sc: supracoxal spine (setae elc.p), vu: vulva. Scale bars = 20 μm (A, B, G, H) and 1 μm (C–F).