A New Stubby Species of Demodectic Mite (Acari: Demodicidae) From the Domestic Dog (Canidae)

A New Stubby Species of Demodectic Mite (Acari: Demodicidae) From the Domestic Dog (Canidae) Abstract A new species of Demodex was detected in the earwax of a dog with otitis externa in Saitama Prefecture, Japan, in July 2010. The opisthosoma length of the mite was slightly shorter than 1/2 of its body length, which was different from the other species in domestic dogs, D. canis and D. injai, but was similar to the form of mites termed “short-bodied species”, including D. cornei. However, the stubby external form was morphologically different from those of “short-bodied species”, excluding a case without a species description reported from Greece. Among known species, the mite was similar to D. equi and D. acutipes. Canis familiaris, Demodex, new species, morphology Introduction Demodectic mites parasitize most mammals immediately after birth (Fuss 1933, Greve and Gaafar 1966, Nutting 1975, Ravera et al. 2013), and are considered to be essentially apathogenic, but may occasionally cause severe dermatitis (Elston 2010, Lacey et al. 2011). Demodectic mites are highly host-specific, and multiple species have been reported in some mammalian host species (Nutting 1976). As demodectic mites parasitizing dogs, D. canis Leydig, 1859 and D. injaiDesch and Hillier, 2003, have been described as independent species. In addition to these species, several demodectic mites with short opisthosoma, termed “short-bodied species”, including D. cornei, have been reported without sufficient morphological descriptions according to the ICZN guidelines or specimen deposition for later comparisons (Mason 1993; Chen 1995; Chesney 1999; Saridomichelakis et al. 1999; Tamura et al. 2001; Alvarez et al. 2007; Oliveira 2007; Izdebska 2010; Sakulploy and Sangvaranond 2010; Rejas et al. 2011; Sivajothi et al. 2013, 2015). We found a mite with a shorter opisthosoma in earwax, and compared it with previously reported dog-derived demodectic mites and morphologically similar D. equi Railliet, 1895, and D. acutipesBukva and Preisler, 1988. Materials and Methods Mites were collected from a 7-year-old female Chihuahua that exhibited pruritus of the ears and systemic hair thinning (Ohmi et al. 2011). The dog had no particular previous medical history or underlying disease, including endocrine disease. Deep skin scrapings from the alopecic area and earwax were examined in mineral oil preparations. Mites were detected nine times in independent earwax examinations; however, only a few mites were detected in the third and fourth deep skin scratch examinations simultaneously performed with earwax examinations (Ohmi et al. 2011). Some of the earwax was collected with a swab at the clinic in Saitama Prefecture, Japan (35.807°N/139.717°E) in July 2010, and preserved in 70% ethanol before mounting in Hoyer’s medium on microslides. Observations were made using a differential interference microscope at 400× (Olympus BX-50, Olympus Corporation, Tokyo, Japan), and measurements were conducted using a calibrated ocular micrometer. The description of the species adopted the nomenclature commonly used for superfamily Cheyletoidea, family Demodicidae, and genus Demodex (Nutting 1976, Bochkov 2009). Nomenclature This paper and the nomenclatural act it contains have been registered in Zoobank (www.zoobank.org), 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:E879EE31-10D2-4541-9051-1C37307B9DE6 Demodex cyonis sp. nov. (Figs. 1–16) Fig. 1. View largeDownload slide Photograph of in-hospital oil preparation of male Demodex cyonis sp. nov. Fig. 1. View largeDownload slide Photograph of in-hospital oil preparation of male Demodex cyonis sp. nov. Figs. 2–16. View largeDownload slide Line drawing of Demodex cyonis sp. nov. based on mounted and flattened specimens—Holotype male, dorsal (2) and ventral view (3). Allotype female, dorsal (4) and ventral (5) view. Egg (6). Holotype male gnathosoma, dorsal (7) and ventral (8) view. Allotype female gnathosoma, dorsal (9) and ventral (10) view. Arrangement of opisthosomal organ of allotype (11) and paratype (12–16) female (arrow heads mean openings on opisthosomal ventral surface). Figs. 2–16. View largeDownload slide Line drawing of Demodex cyonis sp. nov. based on mounted and flattened specimens—Holotype male, dorsal (2) and ventral view (3). Allotype female, dorsal (4) and ventral (5) view. Egg (6). Holotype male gnathosoma, dorsal (7) and ventral (8) view. Allotype female gnathosoma, dorsal (9) and ventral (10) view. Arrangement of opisthosomal organ of allotype (11) and paratype (12–16) female (arrow heads mean openings on opisthosomal ventral surface). (urn:lsid:zoobank.org:act:7515B53C-3509-44F7-BAD2-21FB8DFA08DF) Measurements of holotype or allotype in brackets [], followed by the mean and the standard deviation of the mean of the type series including holotype or allotype in each sex, and the range in parentheses (). Male Body length [167.5] 169.38 ± 13.89 (143.8–185.0) µm (n = 8, includes Holotype) (Figs. 2 and 3). Gnathosoma trapezoidal in outline; [22.5] 23.0 ± 1.28 (21.5–25.0) µm long and [27.5] 26.9 ± 2.59 (22.5–30.0) µm wide. Terminal free segment of palp with a minute spine and two relatively large spines on dorsum. Supracoxal spines spaced [13.8] 14.4 ± 1.47 (12.5–17.5) µm apart; each spine as peg-like flexed to midline (Fig. 7). Subgnathosomal setae anterolateral to horseshoe-shaped pharyngeal bulb and spaced [5.0] 5.2 ± 0.35 (5.0–5.8) µm apart (Fig. 8). Podosoma [67.5] 70.2 ± 3.63 (66.3–77.5) µm long and [51.3] 50.9 ± 4.05 (45.0–57.5) µm wide. Spacing of legs along podosoma uniform. Epimeral plate margins meet along midline; posterior margins of leg IV indistinct. Each terminal free segment with pair of claws and two small spines; each claw bifid distally with posteriorly directed spur midway along claw shaft. Claws on a pointed leaf-like base. Small solenidion on dorsum of tarsus of legs I and II. A slit-like dorsal genital aperture at level between leg I and II. Sclerotized aedeagus [27.5] 25.5 ± 2.40 (22.5–30.0) µm long. Two pairs of dorsal podosomal tubercles associated with genital opening; anterior pair even with genital opening and spaced [29.0] 28.3 ± 1.15 (26.3–30.0) µm apart, and the second pair at level of leg II and spaced [27.5] 26.7 ± 0.65 (26.3–27.5) µm apart. Pair of small third dorsal tubercles at level of leg IV. All tubercles roughly circular in outline. Dorsum of podosoma with fingerprint-like pattern of cuticular striations, except in vicinity of genital opening and first and second tubercles (Fig. 2). Opisthosoma [82.5] 81.9 ± 10.22 (62.5–92.5) µm long and [36.3] 38.5 ± 4.93 (32.5–45.0) µm wide; tapering gradually to blunt point. Cuticle with numerous annuli; annulation extending forward onto dorsum of podosoma. Opisthosomal organ narrow tube [17.5] 16.6 ± 1.98 (13.8–20.0) µm long extending forward from flared ventral opening [20.0], 17.03 ± 6.68 (7.5–30.0) µm from opisthosomal terminus (Fig. 3). Female Body length [172.5] 168.8 ± 12.02 (152.5–187.5) µm (n = 6, includes allotype) (Figs. 4, 5, 9–16). Gnathosoma [23.8] 22.4 ± 1.31 (20.0–23.8) µm long and [27.5] 27.7 ± 2.0 (25.0–30.0) µm wide. Dorsal spine arrangement on terminal free segment of palp as in male. Supracoxal spines spaced [15.0] 15.3 ± 1.89 (11.9–17.0) µm apart; each spine as in male (Fig. 9). Subgnathosomal setae as in male and spaced [5.8] 5.0 ± 0.73 (3.8–5.8) µm apart (Fig. 10). Podosoma [77.5] 76.3 ± 10.43 (67.5–96.26) µm long and [50.0] 51.7 ± 4.92 (45.0–60.0) µm wide. Leg structure and spacing, and coxal plates as in male. Large podonotal shield extending from podosoma anterior edge to level of leg III; no finger print-like inscriptions (Fig. 4). The dorsal tubercles absent. Opisthosoma [78.8] 74.9 ± 9.96 (61.3–90.8) µm long and [42.5] 40.6 ± 2.93 (35.0–42.5) µm wide with rounded terminus. Annulation on cuticle as in male. Vulva as longitudinal slit, [5.0] 4.5 ± 0.87 (3.0–5.0) µm long just behind confluence of posterior margins of coxal plates IV (Fig. 5). Opisthosomal organ as lateral pair of blind triangular-like pouches fused on short side [10.0] 7.8 ± 3.01 (5.0–12.5) µm long arising from single ventral opening [15.0] 10.2 ± 4.06 (5.0–15.0) µm from opisthosomal terminus (Figs. 5 and 11). Arrangement of opisthosomal organ varied depending on specimen preparations (Figs. 11–16). Egg Ovoid, 73.8 and 75.0 µm long and 35.0 and 37.5 µm wide. The chorion smooth; without operculum (n = 2) (Fig. 6). Larva No larva in the specimen. Nymph Three broken deutonymphs in the same specimens near adults, no details for description. Type Materials Holotype male (MPM Coll. No. 21315), allotype female (MPM Coll. No. 21316), and paratypes on slides with multiple mites (MPM Coll. No. 21317) are deposited in the Meguro Parasitological Museum (Shimomeguro, Meguro-ku, Tokyo, Japan). In addition, serial digital photographs of holotype and allotype are also deposited as “phototype (Duszynski, 1999)” (MPM Coll. No. 21318) for better discussion in the future because Hoyer’s medium-mounted specimens used to be flattened and over transparent with the lapse of time. Infestation and Location in the Host The domestic dog Canis familiaris Linnaeus, 1758. Generally, it parasitizes the external auditory canal, but the parasitic region expands on the skin surface throughout the body in severe infestation. Etymology The specific epithet cyonis is from the Greek language word, κύων [kýon], meaning domestic dog, which in Greek would be the first observed host animal by Saridomichelakis et al. (1999). Diagnosis Meristic data are presented as the rounded mean of all males (eight individuals) or females (six individuals) of D. cyonis, and of other species in their descriptions for comparisons. D. cyonis is the most similar to D. equi Railliet, 1895 (sensuBennison, 1943 and Hirst, 1919) of the horse, and D. acutipesBukva and Preisler, 1988, according to Izdebska and Fryderyk, 2012, of the red deer. The following differences distinguish these species from D. cyonis (Table 1): Table 1. Body size of Demodex cyonis sp. nov. and related species Species  reporter  Sex  No.  Body lengtha  Gnathosoma lengtha  Gnathosoma widtha  Podosoma lengtha  Podosoma widtha  Opisthosoma lengtha  Opisthosoma widtha  Aedeagus lengtha  D. cyonis sp. nov.    Male  8  169.4 ± 13.89 (143.8–185.0)  23.0 ± 1.28 (21.5–25.0)  26.9 ± 2.59 (22.5–30.0)  70.2 ± 3.63 (66.3–77.5)  50.9 ± 4.05 (45.0–57.5)  81.9 ± 10.22 (62.5–92.5)  38.5 ± 4.93 (32.5–45.0)  25.5 ± 2.40 (22.5–30.0)  Female  6  168.8 ± 12.02 (152.5–187.5)  22.4 ± 1.31 (20.0–23.8)  27.7 ± 2.00 (25.0–30.0)  76.3 ± 10.43 (67.5–96.3)  51.7 ± 4.92 (45.0–60.0)  74.9 ± 9.96 (61.3–90.8)  40.6 ± 2.93 (35.0–42.5)    D. equi  Hirst 1919  Male  3  (190–204)  (34–37)  (44–47)    (62–68)  (74–84)  (50–60)  25  Female  11  (200–232)  (35–40)  (46–55)    (65–70)  (78–102)  (60–63)    D. equi  Bennison 1943  Male  9  (179–207)  (37–41)  (42–46)  (118–126)b    (60–84)    (25–26)  Female  9  (217–236)  (32–34)  (45–50)  (118–132)b    (88–103)      D. acutipes  Bukva & Preisler 1988  Male  20  192.0 ± 10.8  24.7 ± 1.5  35.4 ± 1.7  75.9 ± 2.2  53.7 ± 3.8  91.8 ± 9.8  45.1 ± 2.9  23.1 ± 0.8  Female  20  220.2 ± 9.5  27.7 ± 1.2  40.0 ± 2.1  87.1 ± 2.8  105.3 ± 7.4  105.3 ± 7.4  53.4 ± 3.0    D. acutipes  Izdebska & Fryderyk 2012  Male  7  187.2 ± 6.8 (172.5–192.2)  23.3 ± 2.3 (20.1–25.0)  30.7 ± 4.5 (25.0–35.5)  82.7 ± 4.6 (76.1–87.5)  57.7 ± 6.4 (50.2–65.0)  80.8 ± 10.2 (67.5–92.1)  45.9 ± 2.3 (44.8–51.9)  21.9 ± 0.4 (21.6–22.8)  Female  20  196.6 ± 21.2 (165.2–225.9)  27.6 ± 2.0 (25.0–30.5)  35.1 ± 3.0 (30.5–40.2)  76.2 ± 9.0 (60.2–87.0)  56.7 ± 5.2 (50.0–65.9)  92.7 ± 16.4 (65.9–115.0)  50.5 ± 3.0 (45.9–54.5)    D. canis  Nutting & Desch 1978  Male  10  168.7 ± 5.3  20.4 ± 1.9  22.0 ± 1.9  55.8 ± 5.2  32.9 ± 3.3  91.6 ± 3.9  29.2 ± 1.5  20.0 ± 1.6  Female  17  224.3 ± 18.3  24.0 ± 2.0  22.6 ± 2.9  63.9 ± 3.7  36.9 ± 1.9  135.9 ± 17.7  32.2 ± 1.8    D. injai  Desch & Hillier 2003  Male  20  361.3 ± 43.9 (306–451)  22.1 ± 0.7 (21–24)  28.0 ± 1.7 (25–32)  87.0 ± 3.6 (82–93)  44.3 ± 2.5 (41–47)  253.3 ± 42.3 (198–340)  35.6 ± 2.9 (31–40)  27.6 ± 1.2 (24–29)  Female  20  334.1 ± 28.9 (270–390)  23.4 ± 1.1 (22–25)  29.4 ± 1.2 (28–31)  85.4 ± 2.9 (78–88)  46.5 ± 1.2 (28–31(sic))  225.4 ± 29.1 (162–279)  37.6 ± 1.5 (35–41)    Short-bodied species in dogs   D. sp.  Chesney 1999  Femalec  39  122.6 ± 12.0 (90–148)  19.0 ± 2.6    56.3 ± 8.0    47.2 ± 9.2       D. sp.  Saridomichelakis et al. 1999      165 ± 19 (145–200)          80 ± 18 (67–117)       D. sp.  Tamura et al. 2001  Femalec  50  139 ± 21.6 (14–18)  (21.4–25.7)    82.9 ± 13.0    56.4 ± 10.3  31.5 ± 6.2     D. sp.  Alvarez et al. 2007  Femalec  30  108        25d         D. sp.  Oliveira et al. 2007  Femalec    135.5 ± 6.3 (120.0–145.0)  24.5 ± 0.6 (22.5–25.0)    57.0 ± 3.8 (50.0–65.0)    51.0 ± 5.0 (40.0–60.0)       D. cornei  Sakulploy & Sangvaranond 2010  Male and Femalee  30  156.9 ± 11.12 (132.5–187.5)  23.5 ± 1.9 (17.5–25.0)    60.0 ± 2.5 (55.0–62.5)  39.1 ± 2.3 (32.5–42.5)  59.3 ± 9.7 (62.5–102.5)       D. cornei  Izdebska 2010  Male  30  121 (93–135)        35d (33–40)  47.19      Female  30  137 (125–165)        38d (35–40)  57.54       D. sp.  Rejas et al. 2011  Femalec  15  139.3 ± 10.4 (120–155)  21.9 ± 2.2 (18–25)  20.6 ± 2.3 (18–28)  61.2 ± 4.6 (52–68)  32.7 ± 7.1 (21–44)  56.2 ± 8.4 (48–69)  29.9 ± 2.6 (26–35)    D. cornei  Sivajothi et al. 2013  Male and Femalee  320  137.2 ± 22.8(96–164)  19.3±0.1(18–20)    61.6 ± 0.6 (58–65)  38.3 ± 0.2 (21–44)  58.6 ± 1.6 (46–72)      D. cornei  Sivajothi et al. 2015  Male and Femalee  26  132.2 ± 14.6(96–152)  19.1±0.1(18–20)    61.1 ± 0.3(59–64)    61.5 ± 2.4 (49–76)      Species  reporter  Sex  No.  Body lengtha  Gnathosoma lengtha  Gnathosoma widtha  Podosoma lengtha  Podosoma widtha  Opisthosoma lengtha  Opisthosoma widtha  Aedeagus lengtha  D. cyonis sp. nov.    Male  8  169.4 ± 13.89 (143.8–185.0)  23.0 ± 1.28 (21.5–25.0)  26.9 ± 2.59 (22.5–30.0)  70.2 ± 3.63 (66.3–77.5)  50.9 ± 4.05 (45.0–57.5)  81.9 ± 10.22 (62.5–92.5)  38.5 ± 4.93 (32.5–45.0)  25.5 ± 2.40 (22.5–30.0)  Female  6  168.8 ± 12.02 (152.5–187.5)  22.4 ± 1.31 (20.0–23.8)  27.7 ± 2.00 (25.0–30.0)  76.3 ± 10.43 (67.5–96.3)  51.7 ± 4.92 (45.0–60.0)  74.9 ± 9.96 (61.3–90.8)  40.6 ± 2.93 (35.0–42.5)    D. equi  Hirst 1919  Male  3  (190–204)  (34–37)  (44–47)    (62–68)  (74–84)  (50–60)  25  Female  11  (200–232)  (35–40)  (46–55)    (65–70)  (78–102)  (60–63)    D. equi  Bennison 1943  Male  9  (179–207)  (37–41)  (42–46)  (118–126)b    (60–84)    (25–26)  Female  9  (217–236)  (32–34)  (45–50)  (118–132)b    (88–103)      D. acutipes  Bukva & Preisler 1988  Male  20  192.0 ± 10.8  24.7 ± 1.5  35.4 ± 1.7  75.9 ± 2.2  53.7 ± 3.8  91.8 ± 9.8  45.1 ± 2.9  23.1 ± 0.8  Female  20  220.2 ± 9.5  27.7 ± 1.2  40.0 ± 2.1  87.1 ± 2.8  105.3 ± 7.4  105.3 ± 7.4  53.4 ± 3.0    D. acutipes  Izdebska & Fryderyk 2012  Male  7  187.2 ± 6.8 (172.5–192.2)  23.3 ± 2.3 (20.1–25.0)  30.7 ± 4.5 (25.0–35.5)  82.7 ± 4.6 (76.1–87.5)  57.7 ± 6.4 (50.2–65.0)  80.8 ± 10.2 (67.5–92.1)  45.9 ± 2.3 (44.8–51.9)  21.9 ± 0.4 (21.6–22.8)  Female  20  196.6 ± 21.2 (165.2–225.9)  27.6 ± 2.0 (25.0–30.5)  35.1 ± 3.0 (30.5–40.2)  76.2 ± 9.0 (60.2–87.0)  56.7 ± 5.2 (50.0–65.9)  92.7 ± 16.4 (65.9–115.0)  50.5 ± 3.0 (45.9–54.5)    D. canis  Nutting & Desch 1978  Male  10  168.7 ± 5.3  20.4 ± 1.9  22.0 ± 1.9  55.8 ± 5.2  32.9 ± 3.3  91.6 ± 3.9  29.2 ± 1.5  20.0 ± 1.6  Female  17  224.3 ± 18.3  24.0 ± 2.0  22.6 ± 2.9  63.9 ± 3.7  36.9 ± 1.9  135.9 ± 17.7  32.2 ± 1.8    D. injai  Desch & Hillier 2003  Male  20  361.3 ± 43.9 (306–451)  22.1 ± 0.7 (21–24)  28.0 ± 1.7 (25–32)  87.0 ± 3.6 (82–93)  44.3 ± 2.5 (41–47)  253.3 ± 42.3 (198–340)  35.6 ± 2.9 (31–40)  27.6 ± 1.2 (24–29)  Female  20  334.1 ± 28.9 (270–390)  23.4 ± 1.1 (22–25)  29.4 ± 1.2 (28–31)  85.4 ± 2.9 (78–88)  46.5 ± 1.2 (28–31(sic))  225.4 ± 29.1 (162–279)  37.6 ± 1.5 (35–41)    Short-bodied species in dogs   D. sp.  Chesney 1999  Femalec  39  122.6 ± 12.0 (90–148)  19.0 ± 2.6    56.3 ± 8.0    47.2 ± 9.2       D. sp.  Saridomichelakis et al. 1999      165 ± 19 (145–200)          80 ± 18 (67–117)       D. sp.  Tamura et al. 2001  Femalec  50  139 ± 21.6 (14–18)  (21.4–25.7)    82.9 ± 13.0    56.4 ± 10.3  31.5 ± 6.2     D. sp.  Alvarez et al. 2007  Femalec  30  108        25d         D. sp.  Oliveira et al. 2007  Femalec    135.5 ± 6.3 (120.0–145.0)  24.5 ± 0.6 (22.5–25.0)    57.0 ± 3.8 (50.0–65.0)    51.0 ± 5.0 (40.0–60.0)       D. cornei  Sakulploy & Sangvaranond 2010  Male and Femalee  30  156.9 ± 11.12 (132.5–187.5)  23.5 ± 1.9 (17.5–25.0)    60.0 ± 2.5 (55.0–62.5)  39.1 ± 2.3 (32.5–42.5)  59.3 ± 9.7 (62.5–102.5)       D. cornei  Izdebska 2010  Male  30  121 (93–135)        35d (33–40)  47.19      Female  30  137 (125–165)        38d (35–40)  57.54       D. sp.  Rejas et al. 2011  Femalec  15  139.3 ± 10.4 (120–155)  21.9 ± 2.2 (18–25)  20.6 ± 2.3 (18–28)  61.2 ± 4.6 (52–68)  32.7 ± 7.1 (21–44)  56.2 ± 8.4 (48–69)  29.9 ± 2.6 (26–35)    D. cornei  Sivajothi et al. 2013  Male and Femalee  320  137.2 ± 22.8(96–164)  19.3±0.1(18–20)    61.6 ± 0.6 (58–65)  38.3 ± 0.2 (21–44)  58.6 ± 1.6 (46–72)      D. cornei  Sivajothi et al. 2015  Male and Femalee  26  132.2 ± 14.6(96–152)  19.1±0.1(18–20)    61.1 ± 0.3(59–64)    61.5 ± 2.4 (49–76)      Blank spaces mean no-description in the repot. Sic, quoted as it is from the original description. aMean ± standard deviation (range) in µm. bThe authors expressed as “length of capitulum + thorax” correspond to “gnathosoma length” + “podosoma length” in their report. cDescribed female only. dThe authors expressed as “body width” in their report. eThe authors measured mites of both sexes in a lump. View Large A large podonotal shield is present in the females of D. cyonis (Fig. 3); the podonotal shield is absent in the females of D. equi and D. acutipes. The length and width of gnathosoma of the females of D. cyonis (maximum values, 24 and 30, respectively) were shorter than those of females of D. equi (minimum values, 32 and 45, respectively) and D. acutipes (minimum values, 25 and 31, respectively). The following differences distinguish D. cyonis and D. canis Leydig, 1859 (redescription, Nutting and Desch, 1978) (Table 1). The opisthosomal organ of D. cyonis males is a narrow tube extending forward; the opisthosomal organ is absent in D. canis males. The opisthosomal organ of D. cyonis females is a pair of elongated triangle-like pouches; the opisthosomal organ of D. canis females is a single finger-like extension backward. The average distance between the first pair of tubercles around the genital opening of the male dorsal podosoma is 28.3 µm and that of the second pair of tubercles is 26.7 µm in D. cyonis; those of D. canis are both 20 µm. The podosoma length of D. cyonis males is more than 1.2-fold longer than that of D. canis males. The ratio of the average opisthosoma length to the average body length of D. cyonis is less than half (male 0.48, female 0.44), whereas that in D. canis is more than half (male 0.54, female 0.61). The widths of the gnathosoma, podosome, and opisthosoma of both sexes of D. cyonis are 1.2- to 1.5-fold larger than those of D. canis; both sexes of D. cyonis are stubbier in shape than D. canis. The following differences distinguish D. cyonis and D. injaiDesch and Hillier, 2003 (Table 1). Although the opisthosomal organs of the males of both species are a narrow tube extending forward, the average length for D. cyonis is 16.56 µm and that for D. injai is 98.9 µm. The opisthosomal organ of D. cyonis females is a lateral pair of triangular pouches arising from a single ventral opening, whereas that of D. injai is a finger-like extension backward. The body lengths of both sexes of D. cyonis are approximately half of D. injai. The ratios of the average opisthosoma length to average body length of both sexes of D. cyonis are less than half, whereas those in D. injai are more than two-thirds (male 0.70, female 0.67). Discussion The mite was distinguished from the morphologically similar species, D. equi and D. acutipes, and from the known species in dogs, D. canis and D. injai, based on the characteristics described in “Diagnosis”. Since the morphological characteristics of “short-bodied species” from dogs including D. cornei in 10 previous studies were not described in detail, excluding body and opisthosoma lengths (Table 1), detailed comparisons with D. cyonis were difficult. However, mean body lengths ranged between 108 μm (minimum in Alvarez et al. 2007) and 139.3 μm (maximum in Tamura et al. 2001), which appeared to be smaller than that (168.75 μm) of female D. cyonis, excluding the 165-µm mite reported by Saridomichelakis et al. (1999) and 156.9-μm mite reported by Sakulploy and Sangvaranond (2010) (Table 1). In addition, mean podosoma lengths ranged between 56.3 (minimum in Chesney 1999) and 61.6 (maximum in Sivajothi et al. 2013) μm, which appeared to be smaller than that (76.3 μm) of female D. cyonis, excluding the approximately 85-μm mite (according to our calculation) reported by Saridomichelakis et al. (1999) and 82.9-μm mite reported by Tamura et al. (2001) (Table 1). Furthermore, although the values measured were not presented in the studies, morphologies read from photographs and schematic diagrams of the mites in those studies, and the gnathosoma, podosoma, and opisthosoma widths estimated from body lengths may be equivalent to D. canis, excluding those reported by Saridomichelakis et al. (1999). Therefore, “short-bodied species” and D. cyonis may be differentiated based on the criteria of the widths of the body parts of D. canis, excluding the opisthosoma length and its ratio to body length. In addition, a band-like plate, observed dorsally between podosoma and opisthosoma in some studies on “short-bodied species” including D. cornei (Izdebska 2010, Izdebska and Fryderyk 2011, Rejas et al. 2011, Tamura et al. 2001), was absent in D. cyonis. As described above, D. cyonis may be distinguishable from all previously reported “short-bodied species”, including D. cornei (Chesney 1999; Tater and Patterson 2008; Izdebska 2010; Sakulploy 2010; Sivajothi et al. 2013, 2015), except for that described by Saridomichelakis et al. (1999). Saridomichelakis et al. (1999) reported body and opisthosoma lengths only and provided photographs of the ventral side; however, they were consistent with those of D. cyonis, suggesting that the mite species observed was identical to D. cyonis. Most stages of the life cycle of D. cyonis, including eggs, were detected in earwax, and mites were only detected in the ear in periods other than the peak infestation period, suggesting that the original habitat site of this species was the surface of the external auditory canal; however, the parasitic region transiently expands over the skin when parasitism aggravates. In the two cases reported by Saridomichelakis et al. (1999), the parasitic region was the systemic skin surface; however, these dogs had hyper-adrenocorticism and hypothyroidism, respectively, suggesting aggravation due to reduced immunity. If the species reported was identical to D. cyonis, reduced immunity in the hosts may have led to the expansion of the parasitic region from the ear to the body surface and induced generalized demodicosis. D. cyonis may be detected by careful observations of the earwax of dogs. Version of Record, first published online January 4, 2018 with fixed content and layout in compliance with Art. 8.1.3.2 ICZN. References Cited Alvarez, L., Medina O. C., García M. E., and García H.. 2007. First report of an unclassified Demodex mite causing demodicosis in a Venezuelan dog. Ann. Trop. Med. Parasitol . 101: 529– 532. Google Scholar CrossRef Search ADS PubMed  Bennison, J. C. 1943. Demodicosis of horses with particular reference to equine members of the genus Demodex. J. R. Army Vet. Corps  14: 34– 49, 66–73. Bochkov, A. V. 2009. A review of mites of the Parvorder Eleutherengona (Acariformes: Prostigmata) - permanent parasites of mammals. Acarina  Supp. 1, 1– 149. Bukva, V., and Preisler J.. 1988. Observations on the morphology of the hair follicle mites (Acari: Demodicidae) from Cervus elaphus L., 1758 including description of Demodex acutipes sp. n. Folia Parasitol. (Praha) . 35: 67– 75. Google Scholar PubMed  Chen, C. 1995. A short-tailed demodectic mite and Demodex canis infestation in a Chihuahua dog. Vet. Dermatol . 6: 227– 229. Google Scholar CrossRef Search ADS   Chesney, C. J. 1999. Short form of Demodex species mite in the dog: occurrence and measurements. J. Small Anim. Pract . 40: 58– 61. Google Scholar CrossRef Search ADS PubMed  Desch, C. E., and Hillier A.. 2003. Demodex injai: a new species of hair follicle mite (Acari: Demodecidae) from the domestic dog (Canidae). J. Med. Entomol . 40: 146– 149. Google Scholar CrossRef Search ADS PubMed  Duszynski, D. W. 1999. Revisiting the code: clarifying name-bearing types for photomicrographs of protozoa. J. Parasitol . 85: 769– 770. Google Scholar CrossRef Search ADS PubMed  Elston, D. M. 2010. Demodex mites: facts and controversies. Clin. Dermatol . 28: 502– 504. Google Scholar CrossRef Search ADS PubMed  Fuss, F. 1933. La vie parasitaire due Demodex folliculorum hominis. Ann. Dermatol. Syphiligr. (Paris) Sér . 74: 1053– 1062. Greve, J. H., and Gaafar S. M.. 1966. Natural transmission of Demodex canis in dogs. J. Am. Vet. Med. Assoc . 148: 1043– 1045. Google Scholar PubMed  Hirst, S. 1919. Studies on Acari. No. 1. The genus Demodex, Owen . British Museum (Natural History), London, United Kingdom. Izdebska, J. N. 2010. Demodex sp. (Acari, Demodecidae) and demodecosis in dogs: characteristics, symptoms, occurrence. Bull. Vet. Inst. Pulawy  54: 335– 338. Izdebska, J. N., and Fryderyk S.. 2011. Diversity of three species of the genus Demodex (Acari, Demodecidae) parasitizing dogs in Poland. Polish J. Env. Stud . 20: 565– 569. Izdebska, J. N., and Fryderyk S.. 2012. Demodex acutipes Bukva et Preisler, 1988 (Acari, Demodecidae)–a rare parasite of red deer (Cervus elaphus L.). Ann. Parasitol . 58: 161– 166. Google Scholar PubMed  Lacey, N., Ní Raghallaigh S., and Powell F. C.. 2011. Demodex mites–commensals, parasites or mutualistic organisms? Dermatology . 222: 128– 130. Google Scholar CrossRef Search ADS PubMed  Mason, K. V. 1993. A new species of Demodex mite with D. canis causing canine demodecosis: a case report. Vet. Dermatol . 4: 37. Google Scholar CrossRef Search ADS   Nutting, W. B. 1975. Hair follicle mites (Demodex spp.) in New Zealand. N. Z. J. Zool . 2: 219– 222. Google Scholar CrossRef Search ADS   Nutting, W. B. 1976. Hair follicle mites (Demodex spp.) of medical and veterinary concern. Cornell Vet . 66: 214– 231. Google Scholar PubMed  Nutting, W. B., and Desch C. E.. 1978. Demodex canis: redescription and reevaluation. Cornell Vet . 68: 139– 149. Google Scholar PubMed  Ohmi, A., Kiwaki A., Seki A., Taira Y., Itagaki H., Nagata K., Morita T., and Imai S.. 2011. Otitis externa and dermatitis associated with small demodectic mites in a dog, p. 98. In Proceedings, 14th Annual Congress of the Japanese Society of Veterinary Dermatology, 11–13 March 2011, Yokohama, Japan (In Japanese). Oliveira, A., Leitão J. P., Grácio A. J. S., and Fonseca I. P.. 2007. Short-tailed forms of Demodex in the dog - first description in Portugal. Revista Portuguesa de Clências Veterinárias  102: 249– 252 (In Portuguese). Rejas, L. J., Reyero D. R., and Baños D. N.. 2011. First report of canine demodicosis by short-bodied Demodex mite (Acari: Demodecidae) in Spain. Experiencia Clínica  70: 219– 224. Ravera, I., Altet L., Francino O., Sánchez A., Roldán W., Villanueva S., Bardagí M., and Ferrer L.. 2013. Small Demodex populations colonize most parts of the skin of healthy dogs. Vet. Dermatol . 24: 168– 72.e37. Google Scholar CrossRef Search ADS PubMed  Sakulploy, R., and Sangvaranond A.. 2010. Canine Demodicosis caused by Demodex canis and short opisthosomal Demodex cornei in Shi Tzu dog from Bangkok Metropolitan Thailand. Kasetsart Veterinarians  20: 27– 35. Saridomichelakis, M., Koutinas A., Papadogiannakis E., Papazachariadou M., Liapi M., and Trakas D.. 1999. Adult-onset demodicosis in two dogs due to Demodex canis and a short-tailed demodectic mite. J. Small Anim. Pract . 40: 529– 532. Google Scholar CrossRef Search ADS PubMed  Sivajothi, S., Reddy B. S., Kumari K. N., and Rayulu V. C.. 2013. Morphometry of Demodex canis and Demodex cornei in dogs with demodicosis in India. Int. J. Vet. Health Sci. Res . 1: 6– 8. Sivajothi, S., Sudhakara Reddy B., and Rayulu V. C.. 2015. Demodicosis caused by Demodex canis and Demodex cornei in dogs. J. Parasit. Dis . 39: 673– 676. Google Scholar CrossRef Search ADS PubMed  Tamura, Y., Kawamura Y., Inoue I., and Ishino S.. 2001. Scanning electron microscopy description of a new species of Demodex canis spp. Vet. Dermatol . 12: 275– 278. Google Scholar CrossRef Search ADS PubMed  Tater, K. C., and Patterson, A. P. 2008. Canine and feline demodicosis. Vet. Med . 103: 444– 461. © The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of Medical Entomology Oxford University Press

A New Stubby Species of Demodectic Mite (Acari: Demodicidae) From the Domestic Dog (Canidae)

Loading next page...
 
/lp/ou_press/a-new-stubby-species-of-demodectic-mite-acari-demodicidae-from-the-VONAZ0Nv6f
Publisher
Oxford University Press
Copyright
© The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
ISSN
0022-2585
eISSN
1938-2928
D.O.I.
10.1093/jme/tjx226
Publisher site
See Article on Publisher Site

Abstract

Abstract A new species of Demodex was detected in the earwax of a dog with otitis externa in Saitama Prefecture, Japan, in July 2010. The opisthosoma length of the mite was slightly shorter than 1/2 of its body length, which was different from the other species in domestic dogs, D. canis and D. injai, but was similar to the form of mites termed “short-bodied species”, including D. cornei. However, the stubby external form was morphologically different from those of “short-bodied species”, excluding a case without a species description reported from Greece. Among known species, the mite was similar to D. equi and D. acutipes. Canis familiaris, Demodex, new species, morphology Introduction Demodectic mites parasitize most mammals immediately after birth (Fuss 1933, Greve and Gaafar 1966, Nutting 1975, Ravera et al. 2013), and are considered to be essentially apathogenic, but may occasionally cause severe dermatitis (Elston 2010, Lacey et al. 2011). Demodectic mites are highly host-specific, and multiple species have been reported in some mammalian host species (Nutting 1976). As demodectic mites parasitizing dogs, D. canis Leydig, 1859 and D. injaiDesch and Hillier, 2003, have been described as independent species. In addition to these species, several demodectic mites with short opisthosoma, termed “short-bodied species”, including D. cornei, have been reported without sufficient morphological descriptions according to the ICZN guidelines or specimen deposition for later comparisons (Mason 1993; Chen 1995; Chesney 1999; Saridomichelakis et al. 1999; Tamura et al. 2001; Alvarez et al. 2007; Oliveira 2007; Izdebska 2010; Sakulploy and Sangvaranond 2010; Rejas et al. 2011; Sivajothi et al. 2013, 2015). We found a mite with a shorter opisthosoma in earwax, and compared it with previously reported dog-derived demodectic mites and morphologically similar D. equi Railliet, 1895, and D. acutipesBukva and Preisler, 1988. Materials and Methods Mites were collected from a 7-year-old female Chihuahua that exhibited pruritus of the ears and systemic hair thinning (Ohmi et al. 2011). The dog had no particular previous medical history or underlying disease, including endocrine disease. Deep skin scrapings from the alopecic area and earwax were examined in mineral oil preparations. Mites were detected nine times in independent earwax examinations; however, only a few mites were detected in the third and fourth deep skin scratch examinations simultaneously performed with earwax examinations (Ohmi et al. 2011). Some of the earwax was collected with a swab at the clinic in Saitama Prefecture, Japan (35.807°N/139.717°E) in July 2010, and preserved in 70% ethanol before mounting in Hoyer’s medium on microslides. Observations were made using a differential interference microscope at 400× (Olympus BX-50, Olympus Corporation, Tokyo, Japan), and measurements were conducted using a calibrated ocular micrometer. The description of the species adopted the nomenclature commonly used for superfamily Cheyletoidea, family Demodicidae, and genus Demodex (Nutting 1976, Bochkov 2009). Nomenclature This paper and the nomenclatural act it contains have been registered in Zoobank (www.zoobank.org), 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:E879EE31-10D2-4541-9051-1C37307B9DE6 Demodex cyonis sp. nov. (Figs. 1–16) Fig. 1. View largeDownload slide Photograph of in-hospital oil preparation of male Demodex cyonis sp. nov. Fig. 1. View largeDownload slide Photograph of in-hospital oil preparation of male Demodex cyonis sp. nov. Figs. 2–16. View largeDownload slide Line drawing of Demodex cyonis sp. nov. based on mounted and flattened specimens—Holotype male, dorsal (2) and ventral view (3). Allotype female, dorsal (4) and ventral (5) view. Egg (6). Holotype male gnathosoma, dorsal (7) and ventral (8) view. Allotype female gnathosoma, dorsal (9) and ventral (10) view. Arrangement of opisthosomal organ of allotype (11) and paratype (12–16) female (arrow heads mean openings on opisthosomal ventral surface). Figs. 2–16. View largeDownload slide Line drawing of Demodex cyonis sp. nov. based on mounted and flattened specimens—Holotype male, dorsal (2) and ventral view (3). Allotype female, dorsal (4) and ventral (5) view. Egg (6). Holotype male gnathosoma, dorsal (7) and ventral (8) view. Allotype female gnathosoma, dorsal (9) and ventral (10) view. Arrangement of opisthosomal organ of allotype (11) and paratype (12–16) female (arrow heads mean openings on opisthosomal ventral surface). (urn:lsid:zoobank.org:act:7515B53C-3509-44F7-BAD2-21FB8DFA08DF) Measurements of holotype or allotype in brackets [], followed by the mean and the standard deviation of the mean of the type series including holotype or allotype in each sex, and the range in parentheses (). Male Body length [167.5] 169.38 ± 13.89 (143.8–185.0) µm (n = 8, includes Holotype) (Figs. 2 and 3). Gnathosoma trapezoidal in outline; [22.5] 23.0 ± 1.28 (21.5–25.0) µm long and [27.5] 26.9 ± 2.59 (22.5–30.0) µm wide. Terminal free segment of palp with a minute spine and two relatively large spines on dorsum. Supracoxal spines spaced [13.8] 14.4 ± 1.47 (12.5–17.5) µm apart; each spine as peg-like flexed to midline (Fig. 7). Subgnathosomal setae anterolateral to horseshoe-shaped pharyngeal bulb and spaced [5.0] 5.2 ± 0.35 (5.0–5.8) µm apart (Fig. 8). Podosoma [67.5] 70.2 ± 3.63 (66.3–77.5) µm long and [51.3] 50.9 ± 4.05 (45.0–57.5) µm wide. Spacing of legs along podosoma uniform. Epimeral plate margins meet along midline; posterior margins of leg IV indistinct. Each terminal free segment with pair of claws and two small spines; each claw bifid distally with posteriorly directed spur midway along claw shaft. Claws on a pointed leaf-like base. Small solenidion on dorsum of tarsus of legs I and II. A slit-like dorsal genital aperture at level between leg I and II. Sclerotized aedeagus [27.5] 25.5 ± 2.40 (22.5–30.0) µm long. Two pairs of dorsal podosomal tubercles associated with genital opening; anterior pair even with genital opening and spaced [29.0] 28.3 ± 1.15 (26.3–30.0) µm apart, and the second pair at level of leg II and spaced [27.5] 26.7 ± 0.65 (26.3–27.5) µm apart. Pair of small third dorsal tubercles at level of leg IV. All tubercles roughly circular in outline. Dorsum of podosoma with fingerprint-like pattern of cuticular striations, except in vicinity of genital opening and first and second tubercles (Fig. 2). Opisthosoma [82.5] 81.9 ± 10.22 (62.5–92.5) µm long and [36.3] 38.5 ± 4.93 (32.5–45.0) µm wide; tapering gradually to blunt point. Cuticle with numerous annuli; annulation extending forward onto dorsum of podosoma. Opisthosomal organ narrow tube [17.5] 16.6 ± 1.98 (13.8–20.0) µm long extending forward from flared ventral opening [20.0], 17.03 ± 6.68 (7.5–30.0) µm from opisthosomal terminus (Fig. 3). Female Body length [172.5] 168.8 ± 12.02 (152.5–187.5) µm (n = 6, includes allotype) (Figs. 4, 5, 9–16). Gnathosoma [23.8] 22.4 ± 1.31 (20.0–23.8) µm long and [27.5] 27.7 ± 2.0 (25.0–30.0) µm wide. Dorsal spine arrangement on terminal free segment of palp as in male. Supracoxal spines spaced [15.0] 15.3 ± 1.89 (11.9–17.0) µm apart; each spine as in male (Fig. 9). Subgnathosomal setae as in male and spaced [5.8] 5.0 ± 0.73 (3.8–5.8) µm apart (Fig. 10). Podosoma [77.5] 76.3 ± 10.43 (67.5–96.26) µm long and [50.0] 51.7 ± 4.92 (45.0–60.0) µm wide. Leg structure and spacing, and coxal plates as in male. Large podonotal shield extending from podosoma anterior edge to level of leg III; no finger print-like inscriptions (Fig. 4). The dorsal tubercles absent. Opisthosoma [78.8] 74.9 ± 9.96 (61.3–90.8) µm long and [42.5] 40.6 ± 2.93 (35.0–42.5) µm wide with rounded terminus. Annulation on cuticle as in male. Vulva as longitudinal slit, [5.0] 4.5 ± 0.87 (3.0–5.0) µm long just behind confluence of posterior margins of coxal plates IV (Fig. 5). Opisthosomal organ as lateral pair of blind triangular-like pouches fused on short side [10.0] 7.8 ± 3.01 (5.0–12.5) µm long arising from single ventral opening [15.0] 10.2 ± 4.06 (5.0–15.0) µm from opisthosomal terminus (Figs. 5 and 11). Arrangement of opisthosomal organ varied depending on specimen preparations (Figs. 11–16). Egg Ovoid, 73.8 and 75.0 µm long and 35.0 and 37.5 µm wide. The chorion smooth; without operculum (n = 2) (Fig. 6). Larva No larva in the specimen. Nymph Three broken deutonymphs in the same specimens near adults, no details for description. Type Materials Holotype male (MPM Coll. No. 21315), allotype female (MPM Coll. No. 21316), and paratypes on slides with multiple mites (MPM Coll. No. 21317) are deposited in the Meguro Parasitological Museum (Shimomeguro, Meguro-ku, Tokyo, Japan). In addition, serial digital photographs of holotype and allotype are also deposited as “phototype (Duszynski, 1999)” (MPM Coll. No. 21318) for better discussion in the future because Hoyer’s medium-mounted specimens used to be flattened and over transparent with the lapse of time. Infestation and Location in the Host The domestic dog Canis familiaris Linnaeus, 1758. Generally, it parasitizes the external auditory canal, but the parasitic region expands on the skin surface throughout the body in severe infestation. Etymology The specific epithet cyonis is from the Greek language word, κύων [kýon], meaning domestic dog, which in Greek would be the first observed host animal by Saridomichelakis et al. (1999). Diagnosis Meristic data are presented as the rounded mean of all males (eight individuals) or females (six individuals) of D. cyonis, and of other species in their descriptions for comparisons. D. cyonis is the most similar to D. equi Railliet, 1895 (sensuBennison, 1943 and Hirst, 1919) of the horse, and D. acutipesBukva and Preisler, 1988, according to Izdebska and Fryderyk, 2012, of the red deer. The following differences distinguish these species from D. cyonis (Table 1): Table 1. Body size of Demodex cyonis sp. nov. and related species Species  reporter  Sex  No.  Body lengtha  Gnathosoma lengtha  Gnathosoma widtha  Podosoma lengtha  Podosoma widtha  Opisthosoma lengtha  Opisthosoma widtha  Aedeagus lengtha  D. cyonis sp. nov.    Male  8  169.4 ± 13.89 (143.8–185.0)  23.0 ± 1.28 (21.5–25.0)  26.9 ± 2.59 (22.5–30.0)  70.2 ± 3.63 (66.3–77.5)  50.9 ± 4.05 (45.0–57.5)  81.9 ± 10.22 (62.5–92.5)  38.5 ± 4.93 (32.5–45.0)  25.5 ± 2.40 (22.5–30.0)  Female  6  168.8 ± 12.02 (152.5–187.5)  22.4 ± 1.31 (20.0–23.8)  27.7 ± 2.00 (25.0–30.0)  76.3 ± 10.43 (67.5–96.3)  51.7 ± 4.92 (45.0–60.0)  74.9 ± 9.96 (61.3–90.8)  40.6 ± 2.93 (35.0–42.5)    D. equi  Hirst 1919  Male  3  (190–204)  (34–37)  (44–47)    (62–68)  (74–84)  (50–60)  25  Female  11  (200–232)  (35–40)  (46–55)    (65–70)  (78–102)  (60–63)    D. equi  Bennison 1943  Male  9  (179–207)  (37–41)  (42–46)  (118–126)b    (60–84)    (25–26)  Female  9  (217–236)  (32–34)  (45–50)  (118–132)b    (88–103)      D. acutipes  Bukva & Preisler 1988  Male  20  192.0 ± 10.8  24.7 ± 1.5  35.4 ± 1.7  75.9 ± 2.2  53.7 ± 3.8  91.8 ± 9.8  45.1 ± 2.9  23.1 ± 0.8  Female  20  220.2 ± 9.5  27.7 ± 1.2  40.0 ± 2.1  87.1 ± 2.8  105.3 ± 7.4  105.3 ± 7.4  53.4 ± 3.0    D. acutipes  Izdebska & Fryderyk 2012  Male  7  187.2 ± 6.8 (172.5–192.2)  23.3 ± 2.3 (20.1–25.0)  30.7 ± 4.5 (25.0–35.5)  82.7 ± 4.6 (76.1–87.5)  57.7 ± 6.4 (50.2–65.0)  80.8 ± 10.2 (67.5–92.1)  45.9 ± 2.3 (44.8–51.9)  21.9 ± 0.4 (21.6–22.8)  Female  20  196.6 ± 21.2 (165.2–225.9)  27.6 ± 2.0 (25.0–30.5)  35.1 ± 3.0 (30.5–40.2)  76.2 ± 9.0 (60.2–87.0)  56.7 ± 5.2 (50.0–65.9)  92.7 ± 16.4 (65.9–115.0)  50.5 ± 3.0 (45.9–54.5)    D. canis  Nutting & Desch 1978  Male  10  168.7 ± 5.3  20.4 ± 1.9  22.0 ± 1.9  55.8 ± 5.2  32.9 ± 3.3  91.6 ± 3.9  29.2 ± 1.5  20.0 ± 1.6  Female  17  224.3 ± 18.3  24.0 ± 2.0  22.6 ± 2.9  63.9 ± 3.7  36.9 ± 1.9  135.9 ± 17.7  32.2 ± 1.8    D. injai  Desch & Hillier 2003  Male  20  361.3 ± 43.9 (306–451)  22.1 ± 0.7 (21–24)  28.0 ± 1.7 (25–32)  87.0 ± 3.6 (82–93)  44.3 ± 2.5 (41–47)  253.3 ± 42.3 (198–340)  35.6 ± 2.9 (31–40)  27.6 ± 1.2 (24–29)  Female  20  334.1 ± 28.9 (270–390)  23.4 ± 1.1 (22–25)  29.4 ± 1.2 (28–31)  85.4 ± 2.9 (78–88)  46.5 ± 1.2 (28–31(sic))  225.4 ± 29.1 (162–279)  37.6 ± 1.5 (35–41)    Short-bodied species in dogs   D. sp.  Chesney 1999  Femalec  39  122.6 ± 12.0 (90–148)  19.0 ± 2.6    56.3 ± 8.0    47.2 ± 9.2       D. sp.  Saridomichelakis et al. 1999      165 ± 19 (145–200)          80 ± 18 (67–117)       D. sp.  Tamura et al. 2001  Femalec  50  139 ± 21.6 (14–18)  (21.4–25.7)    82.9 ± 13.0    56.4 ± 10.3  31.5 ± 6.2     D. sp.  Alvarez et al. 2007  Femalec  30  108        25d         D. sp.  Oliveira et al. 2007  Femalec    135.5 ± 6.3 (120.0–145.0)  24.5 ± 0.6 (22.5–25.0)    57.0 ± 3.8 (50.0–65.0)    51.0 ± 5.0 (40.0–60.0)       D. cornei  Sakulploy & Sangvaranond 2010  Male and Femalee  30  156.9 ± 11.12 (132.5–187.5)  23.5 ± 1.9 (17.5–25.0)    60.0 ± 2.5 (55.0–62.5)  39.1 ± 2.3 (32.5–42.5)  59.3 ± 9.7 (62.5–102.5)       D. cornei  Izdebska 2010  Male  30  121 (93–135)        35d (33–40)  47.19      Female  30  137 (125–165)        38d (35–40)  57.54       D. sp.  Rejas et al. 2011  Femalec  15  139.3 ± 10.4 (120–155)  21.9 ± 2.2 (18–25)  20.6 ± 2.3 (18–28)  61.2 ± 4.6 (52–68)  32.7 ± 7.1 (21–44)  56.2 ± 8.4 (48–69)  29.9 ± 2.6 (26–35)    D. cornei  Sivajothi et al. 2013  Male and Femalee  320  137.2 ± 22.8(96–164)  19.3±0.1(18–20)    61.6 ± 0.6 (58–65)  38.3 ± 0.2 (21–44)  58.6 ± 1.6 (46–72)      D. cornei  Sivajothi et al. 2015  Male and Femalee  26  132.2 ± 14.6(96–152)  19.1±0.1(18–20)    61.1 ± 0.3(59–64)    61.5 ± 2.4 (49–76)      Species  reporter  Sex  No.  Body lengtha  Gnathosoma lengtha  Gnathosoma widtha  Podosoma lengtha  Podosoma widtha  Opisthosoma lengtha  Opisthosoma widtha  Aedeagus lengtha  D. cyonis sp. nov.    Male  8  169.4 ± 13.89 (143.8–185.0)  23.0 ± 1.28 (21.5–25.0)  26.9 ± 2.59 (22.5–30.0)  70.2 ± 3.63 (66.3–77.5)  50.9 ± 4.05 (45.0–57.5)  81.9 ± 10.22 (62.5–92.5)  38.5 ± 4.93 (32.5–45.0)  25.5 ± 2.40 (22.5–30.0)  Female  6  168.8 ± 12.02 (152.5–187.5)  22.4 ± 1.31 (20.0–23.8)  27.7 ± 2.00 (25.0–30.0)  76.3 ± 10.43 (67.5–96.3)  51.7 ± 4.92 (45.0–60.0)  74.9 ± 9.96 (61.3–90.8)  40.6 ± 2.93 (35.0–42.5)    D. equi  Hirst 1919  Male  3  (190–204)  (34–37)  (44–47)    (62–68)  (74–84)  (50–60)  25  Female  11  (200–232)  (35–40)  (46–55)    (65–70)  (78–102)  (60–63)    D. equi  Bennison 1943  Male  9  (179–207)  (37–41)  (42–46)  (118–126)b    (60–84)    (25–26)  Female  9  (217–236)  (32–34)  (45–50)  (118–132)b    (88–103)      D. acutipes  Bukva & Preisler 1988  Male  20  192.0 ± 10.8  24.7 ± 1.5  35.4 ± 1.7  75.9 ± 2.2  53.7 ± 3.8  91.8 ± 9.8  45.1 ± 2.9  23.1 ± 0.8  Female  20  220.2 ± 9.5  27.7 ± 1.2  40.0 ± 2.1  87.1 ± 2.8  105.3 ± 7.4  105.3 ± 7.4  53.4 ± 3.0    D. acutipes  Izdebska & Fryderyk 2012  Male  7  187.2 ± 6.8 (172.5–192.2)  23.3 ± 2.3 (20.1–25.0)  30.7 ± 4.5 (25.0–35.5)  82.7 ± 4.6 (76.1–87.5)  57.7 ± 6.4 (50.2–65.0)  80.8 ± 10.2 (67.5–92.1)  45.9 ± 2.3 (44.8–51.9)  21.9 ± 0.4 (21.6–22.8)  Female  20  196.6 ± 21.2 (165.2–225.9)  27.6 ± 2.0 (25.0–30.5)  35.1 ± 3.0 (30.5–40.2)  76.2 ± 9.0 (60.2–87.0)  56.7 ± 5.2 (50.0–65.9)  92.7 ± 16.4 (65.9–115.0)  50.5 ± 3.0 (45.9–54.5)    D. canis  Nutting & Desch 1978  Male  10  168.7 ± 5.3  20.4 ± 1.9  22.0 ± 1.9  55.8 ± 5.2  32.9 ± 3.3  91.6 ± 3.9  29.2 ± 1.5  20.0 ± 1.6  Female  17  224.3 ± 18.3  24.0 ± 2.0  22.6 ± 2.9  63.9 ± 3.7  36.9 ± 1.9  135.9 ± 17.7  32.2 ± 1.8    D. injai  Desch & Hillier 2003  Male  20  361.3 ± 43.9 (306–451)  22.1 ± 0.7 (21–24)  28.0 ± 1.7 (25–32)  87.0 ± 3.6 (82–93)  44.3 ± 2.5 (41–47)  253.3 ± 42.3 (198–340)  35.6 ± 2.9 (31–40)  27.6 ± 1.2 (24–29)  Female  20  334.1 ± 28.9 (270–390)  23.4 ± 1.1 (22–25)  29.4 ± 1.2 (28–31)  85.4 ± 2.9 (78–88)  46.5 ± 1.2 (28–31(sic))  225.4 ± 29.1 (162–279)  37.6 ± 1.5 (35–41)    Short-bodied species in dogs   D. sp.  Chesney 1999  Femalec  39  122.6 ± 12.0 (90–148)  19.0 ± 2.6    56.3 ± 8.0    47.2 ± 9.2       D. sp.  Saridomichelakis et al. 1999      165 ± 19 (145–200)          80 ± 18 (67–117)       D. sp.  Tamura et al. 2001  Femalec  50  139 ± 21.6 (14–18)  (21.4–25.7)    82.9 ± 13.0    56.4 ± 10.3  31.5 ± 6.2     D. sp.  Alvarez et al. 2007  Femalec  30  108        25d         D. sp.  Oliveira et al. 2007  Femalec    135.5 ± 6.3 (120.0–145.0)  24.5 ± 0.6 (22.5–25.0)    57.0 ± 3.8 (50.0–65.0)    51.0 ± 5.0 (40.0–60.0)       D. cornei  Sakulploy & Sangvaranond 2010  Male and Femalee  30  156.9 ± 11.12 (132.5–187.5)  23.5 ± 1.9 (17.5–25.0)    60.0 ± 2.5 (55.0–62.5)  39.1 ± 2.3 (32.5–42.5)  59.3 ± 9.7 (62.5–102.5)       D. cornei  Izdebska 2010  Male  30  121 (93–135)        35d (33–40)  47.19      Female  30  137 (125–165)        38d (35–40)  57.54       D. sp.  Rejas et al. 2011  Femalec  15  139.3 ± 10.4 (120–155)  21.9 ± 2.2 (18–25)  20.6 ± 2.3 (18–28)  61.2 ± 4.6 (52–68)  32.7 ± 7.1 (21–44)  56.2 ± 8.4 (48–69)  29.9 ± 2.6 (26–35)    D. cornei  Sivajothi et al. 2013  Male and Femalee  320  137.2 ± 22.8(96–164)  19.3±0.1(18–20)    61.6 ± 0.6 (58–65)  38.3 ± 0.2 (21–44)  58.6 ± 1.6 (46–72)      D. cornei  Sivajothi et al. 2015  Male and Femalee  26  132.2 ± 14.6(96–152)  19.1±0.1(18–20)    61.1 ± 0.3(59–64)    61.5 ± 2.4 (49–76)      Blank spaces mean no-description in the repot. Sic, quoted as it is from the original description. aMean ± standard deviation (range) in µm. bThe authors expressed as “length of capitulum + thorax” correspond to “gnathosoma length” + “podosoma length” in their report. cDescribed female only. dThe authors expressed as “body width” in their report. eThe authors measured mites of both sexes in a lump. View Large A large podonotal shield is present in the females of D. cyonis (Fig. 3); the podonotal shield is absent in the females of D. equi and D. acutipes. The length and width of gnathosoma of the females of D. cyonis (maximum values, 24 and 30, respectively) were shorter than those of females of D. equi (minimum values, 32 and 45, respectively) and D. acutipes (minimum values, 25 and 31, respectively). The following differences distinguish D. cyonis and D. canis Leydig, 1859 (redescription, Nutting and Desch, 1978) (Table 1). The opisthosomal organ of D. cyonis males is a narrow tube extending forward; the opisthosomal organ is absent in D. canis males. The opisthosomal organ of D. cyonis females is a pair of elongated triangle-like pouches; the opisthosomal organ of D. canis females is a single finger-like extension backward. The average distance between the first pair of tubercles around the genital opening of the male dorsal podosoma is 28.3 µm and that of the second pair of tubercles is 26.7 µm in D. cyonis; those of D. canis are both 20 µm. The podosoma length of D. cyonis males is more than 1.2-fold longer than that of D. canis males. The ratio of the average opisthosoma length to the average body length of D. cyonis is less than half (male 0.48, female 0.44), whereas that in D. canis is more than half (male 0.54, female 0.61). The widths of the gnathosoma, podosome, and opisthosoma of both sexes of D. cyonis are 1.2- to 1.5-fold larger than those of D. canis; both sexes of D. cyonis are stubbier in shape than D. canis. The following differences distinguish D. cyonis and D. injaiDesch and Hillier, 2003 (Table 1). Although the opisthosomal organs of the males of both species are a narrow tube extending forward, the average length for D. cyonis is 16.56 µm and that for D. injai is 98.9 µm. The opisthosomal organ of D. cyonis females is a lateral pair of triangular pouches arising from a single ventral opening, whereas that of D. injai is a finger-like extension backward. The body lengths of both sexes of D. cyonis are approximately half of D. injai. The ratios of the average opisthosoma length to average body length of both sexes of D. cyonis are less than half, whereas those in D. injai are more than two-thirds (male 0.70, female 0.67). Discussion The mite was distinguished from the morphologically similar species, D. equi and D. acutipes, and from the known species in dogs, D. canis and D. injai, based on the characteristics described in “Diagnosis”. Since the morphological characteristics of “short-bodied species” from dogs including D. cornei in 10 previous studies were not described in detail, excluding body and opisthosoma lengths (Table 1), detailed comparisons with D. cyonis were difficult. However, mean body lengths ranged between 108 μm (minimum in Alvarez et al. 2007) and 139.3 μm (maximum in Tamura et al. 2001), which appeared to be smaller than that (168.75 μm) of female D. cyonis, excluding the 165-µm mite reported by Saridomichelakis et al. (1999) and 156.9-μm mite reported by Sakulploy and Sangvaranond (2010) (Table 1). In addition, mean podosoma lengths ranged between 56.3 (minimum in Chesney 1999) and 61.6 (maximum in Sivajothi et al. 2013) μm, which appeared to be smaller than that (76.3 μm) of female D. cyonis, excluding the approximately 85-μm mite (according to our calculation) reported by Saridomichelakis et al. (1999) and 82.9-μm mite reported by Tamura et al. (2001) (Table 1). Furthermore, although the values measured were not presented in the studies, morphologies read from photographs and schematic diagrams of the mites in those studies, and the gnathosoma, podosoma, and opisthosoma widths estimated from body lengths may be equivalent to D. canis, excluding those reported by Saridomichelakis et al. (1999). Therefore, “short-bodied species” and D. cyonis may be differentiated based on the criteria of the widths of the body parts of D. canis, excluding the opisthosoma length and its ratio to body length. In addition, a band-like plate, observed dorsally between podosoma and opisthosoma in some studies on “short-bodied species” including D. cornei (Izdebska 2010, Izdebska and Fryderyk 2011, Rejas et al. 2011, Tamura et al. 2001), was absent in D. cyonis. As described above, D. cyonis may be distinguishable from all previously reported “short-bodied species”, including D. cornei (Chesney 1999; Tater and Patterson 2008; Izdebska 2010; Sakulploy 2010; Sivajothi et al. 2013, 2015), except for that described by Saridomichelakis et al. (1999). Saridomichelakis et al. (1999) reported body and opisthosoma lengths only and provided photographs of the ventral side; however, they were consistent with those of D. cyonis, suggesting that the mite species observed was identical to D. cyonis. Most stages of the life cycle of D. cyonis, including eggs, were detected in earwax, and mites were only detected in the ear in periods other than the peak infestation period, suggesting that the original habitat site of this species was the surface of the external auditory canal; however, the parasitic region transiently expands over the skin when parasitism aggravates. In the two cases reported by Saridomichelakis et al. (1999), the parasitic region was the systemic skin surface; however, these dogs had hyper-adrenocorticism and hypothyroidism, respectively, suggesting aggravation due to reduced immunity. If the species reported was identical to D. cyonis, reduced immunity in the hosts may have led to the expansion of the parasitic region from the ear to the body surface and induced generalized demodicosis. D. cyonis may be detected by careful observations of the earwax of dogs. Version of Record, first published online January 4, 2018 with fixed content and layout in compliance with Art. 8.1.3.2 ICZN. References Cited Alvarez, L., Medina O. C., García M. E., and García H.. 2007. First report of an unclassified Demodex mite causing demodicosis in a Venezuelan dog. Ann. Trop. Med. Parasitol . 101: 529– 532. Google Scholar CrossRef Search ADS PubMed  Bennison, J. C. 1943. Demodicosis of horses with particular reference to equine members of the genus Demodex. J. R. Army Vet. Corps  14: 34– 49, 66–73. Bochkov, A. V. 2009. A review of mites of the Parvorder Eleutherengona (Acariformes: Prostigmata) - permanent parasites of mammals. Acarina  Supp. 1, 1– 149. Bukva, V., and Preisler J.. 1988. Observations on the morphology of the hair follicle mites (Acari: Demodicidae) from Cervus elaphus L., 1758 including description of Demodex acutipes sp. n. Folia Parasitol. (Praha) . 35: 67– 75. Google Scholar PubMed  Chen, C. 1995. A short-tailed demodectic mite and Demodex canis infestation in a Chihuahua dog. Vet. Dermatol . 6: 227– 229. Google Scholar CrossRef Search ADS   Chesney, C. J. 1999. Short form of Demodex species mite in the dog: occurrence and measurements. J. Small Anim. Pract . 40: 58– 61. Google Scholar CrossRef Search ADS PubMed  Desch, C. E., and Hillier A.. 2003. Demodex injai: a new species of hair follicle mite (Acari: Demodecidae) from the domestic dog (Canidae). J. Med. Entomol . 40: 146– 149. Google Scholar CrossRef Search ADS PubMed  Duszynski, D. W. 1999. Revisiting the code: clarifying name-bearing types for photomicrographs of protozoa. J. Parasitol . 85: 769– 770. Google Scholar CrossRef Search ADS PubMed  Elston, D. M. 2010. Demodex mites: facts and controversies. Clin. Dermatol . 28: 502– 504. Google Scholar CrossRef Search ADS PubMed  Fuss, F. 1933. La vie parasitaire due Demodex folliculorum hominis. Ann. Dermatol. Syphiligr. (Paris) Sér . 74: 1053– 1062. Greve, J. H., and Gaafar S. M.. 1966. Natural transmission of Demodex canis in dogs. J. Am. Vet. Med. Assoc . 148: 1043– 1045. Google Scholar PubMed  Hirst, S. 1919. Studies on Acari. No. 1. The genus Demodex, Owen . British Museum (Natural History), London, United Kingdom. Izdebska, J. N. 2010. Demodex sp. (Acari, Demodecidae) and demodecosis in dogs: characteristics, symptoms, occurrence. Bull. Vet. Inst. Pulawy  54: 335– 338. Izdebska, J. N., and Fryderyk S.. 2011. Diversity of three species of the genus Demodex (Acari, Demodecidae) parasitizing dogs in Poland. Polish J. Env. Stud . 20: 565– 569. Izdebska, J. N., and Fryderyk S.. 2012. Demodex acutipes Bukva et Preisler, 1988 (Acari, Demodecidae)–a rare parasite of red deer (Cervus elaphus L.). Ann. Parasitol . 58: 161– 166. Google Scholar PubMed  Lacey, N., Ní Raghallaigh S., and Powell F. C.. 2011. Demodex mites–commensals, parasites or mutualistic organisms? Dermatology . 222: 128– 130. Google Scholar CrossRef Search ADS PubMed  Mason, K. V. 1993. A new species of Demodex mite with D. canis causing canine demodecosis: a case report. Vet. Dermatol . 4: 37. Google Scholar CrossRef Search ADS   Nutting, W. B. 1975. Hair follicle mites (Demodex spp.) in New Zealand. N. Z. J. Zool . 2: 219– 222. Google Scholar CrossRef Search ADS   Nutting, W. B. 1976. Hair follicle mites (Demodex spp.) of medical and veterinary concern. Cornell Vet . 66: 214– 231. Google Scholar PubMed  Nutting, W. B., and Desch C. E.. 1978. Demodex canis: redescription and reevaluation. Cornell Vet . 68: 139– 149. Google Scholar PubMed  Ohmi, A., Kiwaki A., Seki A., Taira Y., Itagaki H., Nagata K., Morita T., and Imai S.. 2011. Otitis externa and dermatitis associated with small demodectic mites in a dog, p. 98. In Proceedings, 14th Annual Congress of the Japanese Society of Veterinary Dermatology, 11–13 March 2011, Yokohama, Japan (In Japanese). Oliveira, A., Leitão J. P., Grácio A. J. S., and Fonseca I. P.. 2007. Short-tailed forms of Demodex in the dog - first description in Portugal. Revista Portuguesa de Clências Veterinárias  102: 249– 252 (In Portuguese). Rejas, L. J., Reyero D. R., and Baños D. N.. 2011. First report of canine demodicosis by short-bodied Demodex mite (Acari: Demodecidae) in Spain. Experiencia Clínica  70: 219– 224. Ravera, I., Altet L., Francino O., Sánchez A., Roldán W., Villanueva S., Bardagí M., and Ferrer L.. 2013. Small Demodex populations colonize most parts of the skin of healthy dogs. Vet. Dermatol . 24: 168– 72.e37. Google Scholar CrossRef Search ADS PubMed  Sakulploy, R., and Sangvaranond A.. 2010. Canine Demodicosis caused by Demodex canis and short opisthosomal Demodex cornei in Shi Tzu dog from Bangkok Metropolitan Thailand. Kasetsart Veterinarians  20: 27– 35. Saridomichelakis, M., Koutinas A., Papadogiannakis E., Papazachariadou M., Liapi M., and Trakas D.. 1999. Adult-onset demodicosis in two dogs due to Demodex canis and a short-tailed demodectic mite. J. Small Anim. Pract . 40: 529– 532. Google Scholar CrossRef Search ADS PubMed  Sivajothi, S., Reddy B. S., Kumari K. N., and Rayulu V. C.. 2013. Morphometry of Demodex canis and Demodex cornei in dogs with demodicosis in India. Int. J. Vet. Health Sci. Res . 1: 6– 8. Sivajothi, S., Sudhakara Reddy B., and Rayulu V. C.. 2015. Demodicosis caused by Demodex canis and Demodex cornei in dogs. J. Parasit. Dis . 39: 673– 676. Google Scholar CrossRef Search ADS PubMed  Tamura, Y., Kawamura Y., Inoue I., and Ishino S.. 2001. Scanning electron microscopy description of a new species of Demodex canis spp. Vet. Dermatol . 12: 275– 278. Google Scholar CrossRef Search ADS PubMed  Tater, K. C., and Patterson, A. P. 2008. Canine and feline demodicosis. Vet. Med . 103: 444– 461. © The Author(s) 2018. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Journal

Journal of Medical EntomologyOxford University Press

Published: Mar 1, 2018

There are no references for this article.

You’re reading a free preview. Subscribe to read the entire article.


DeepDyve is your
personal research library

It’s your single place to instantly
discover and read the research
that matters to you.

Enjoy affordable access to
over 18 million articles from more than
15,000 peer-reviewed journals.

All for just $49/month

Explore the DeepDyve Library

Search

Query the DeepDyve database, plus search all of PubMed and Google Scholar seamlessly

Organize

Save any article or search result from DeepDyve, PubMed, and Google Scholar... all in one place.

Access

Get unlimited, online access to over 18 million full-text articles from more than 15,000 scientific journals.

Your journals are on DeepDyve

Read from thousands of the leading scholarly journals from SpringerNature, Elsevier, Wiley-Blackwell, Oxford University Press and more.

All the latest content is available, no embargo periods.

See the journals in your area

DeepDyve

Freelancer

DeepDyve

Pro

Price

FREE

$49/month
$360/year

Save searches from
Google Scholar,
PubMed

Create lists to
organize your research

Export lists, citations

Read DeepDyve articles

Abstract access only

Unlimited access to over
18 million full-text articles

Print

20 pages / month

PDF Discount

20% off