Cheladonta neda Schluger, Grochovskaja, Ngu, Hoe and Tung, 1960

Antonovskaia, Anastasia A. & Stekolnikov, Alexandr A., 2021, Redescriptions of ten chigger mite species (Acariformes: Trombiculidae) from Vietnam, Zootaxa 4969 (1), pp. 1-53 : 19-23

Cheladonta neda Schluger, Grochovskaja, Ngu, Hoe and Tung, 1960

( Figs. 8C, D , 12–14 )

Cheladonta neda Schluger, Grochovskaja, Ngu, Hoe and Tung, 1960a: 190 , fig. 11.

Schoutedenichia (Schoutedenichia) neda: Vercammen-Grandjean 1965b: 101 ; 1968: 96.

Cheladonta (Cheladonta) neda: Lakshana 1973: 21 ; Chau et al. 2007: 151, fig. 73.

Diagnosis. SIF = 4B-N-3-2110.0000; fsp = 7.7.7; fCx = 1.1.1; fSt = 2.2; fPp = B/b/BbB; fSc: PL ≥ AM> AL; Ip = 473–531; fD = 4H-8-4-8-6-2-2; DS = 31–35; V = 27–31; NDV = 61–66. Eyes 2 + 2. Cheliceral blade with dorsal serration. Standard measurements of type series given in Table 5 .

Description (larva) [based on lectotype, 4 paralectotypes, and 1 additional specimen]. IDIOSOMA ( Figs. 8C, D , 12 ). Eyes 2 + 2; 31–35 barbed dorsal idiosomal setae including two pairs of humeral setae; 4 sternal setae; 27–31 ventral setae; NDV = 61–66.

GNATHOSOMA ( Fig. 13A, B ). Cheliceral blade with tricuspid cap and dorsal serration; cheliceral base with few puncta; gnathobase with sparse puncta and 1 pair of branched setae; galeala nude; palpal claw with 3 prongs; seta on palpal femur branched; seta on palpal genu with 1 branch; dorsal and ventral palpal tibial setae branched, lateral palpal tibial seta with one branch; palpal tarsus with 4 branched setae and tarsala.

SCUTUM ( Fig. 8C ). Nearly rectangular, wider than long, with almost straight posterior margin, moderately covered with small puncta, with 1 AM, 1 pair of ALs and 1 pair of PLs; PLs longer than ALs; sensilla claviform, covered with spikes; sensillum bases situated anterior to level of PLs (PSB – P-PL = 5–9 µm).

LEGS ( Fig. 13C–E ).All 7-segmented, with 1 pair of claws and claw-like empodium. Leg I: coxa with 1 branched seta (1B); trochanter 1B; basifemur 1B; telofemur 5B; genu 4B, 2 genualae, microgenuala; tibia 8B, 2 tibialae, microtibiala; tarsus 22B, tarsala, microtarsala proximal to tarsala, subterminala, parasubterminala, pretarsala. Leg II: coxa 1B; trochanter 1B; basifemur 2B; telofemur 4B; genu 3B, genuala; tibia 6B, 2 tibialae; tarsus 16B, tarsala, microtarsala at level of tarsala, pretarsala. Leg III: coxa 1B; trochanter 1B; basifemur 1B; telofemur 3B; genu 3B, genuala; tibia 6B; tarsus 14B.

Hosts. Leopoldamys edwardsi (= Rattus edwardsi camphaensis D. Tien (nomen nudum )) ( Schluger et al. 1960a), Menetes berdmorei , Tupaia glis ( Lakshana 1973) , Maxomys surifer (this study).

Distribution. Thailand ( Lakshana 1973), Vietnam.

Type material examined ( Fig. 14 ). Lectotype (here designated): larva ZMMU Tdt-3283 (specimen 5) ex Leopoldamys edwardsi No 595, Vietnam, Nghe An Province, Phu Quy , 13 September 1956, coll. I.M. Grochovskaja. Paralectotypes: two larvae, ZMMU Tdt-3283 (specimen 2), ZMMU Tdt-3282 (specimen 4), same collection data as for lectotype ; one larva ZMMU Tdt-3277 (specimen 3) ex Leopoldamys edwardsi No 27, Vietnam, Quang Ninh Province, Ha Long (= Hon Gai ), 1 February 1956, coll. I.M. Grochovskaja ; one larva ZMMU Tdt-3284 (specimen 3) ex Leopoldamys edwardsi No 555, Vietnam, Nghe An Province, Phu Quy , 9 September 1956, coll. I.M. Grochovskaja.

Additional material examined. One larva ZMMU XM14.63k1 (specimen 11) ex Maxomys surifer No CT-63, Vietnam, Dong Nai Province, Dong Nai National Reserve (Cat Tien), 11°24′42.65″N, 107°23′8.58″E, 11 November 2014, coll. Yu. V. Lopatina.

Remarks. The serrated cheliceral blade and shape of scutum (significantly wider than long, with the distance between sensillum bases almost equal to the distance from sensillum base to the lateral scutal margin) confirm that this species belongs to the genus Cheladonta Lipovsky, Crossley and Loomis, 1955 , contrary to the opinion of Vercammen-Grandjean (1968).

According to the original description, C. neda is similar to C. micheneri Lipovsky, Crossley and Loomis, 1955 and differs in “significantly lesser body size, number of dorsal setae, feathered setae on femur and tibia of palps and other characters” ( Schluger et al. 1960a). Actually, C. neda is most similar to C. brevipalpis (André, 1946) described from a gerbil in Tunisia ( Vercammen-Grandjean & André 1967) and differs from the latter by the presence of a 3- pronged palpal claw vs. 4-pronged, two pairs of eyes vs. one pair, shorter legs (Ip = 473–531 vs. 577–613), slightly smaller scutum ( PW = 49–55 and SD = 29–31 vs. 60–64 and 34–35, respectively), and shorter scutal setae (AL = 10–12 and PL = 21–24 vs. 19 and 26–30, respectively). Cheladonta neda is also similar to C. gouldi Lakshana, 1969 and differs from it by the presence of branched dorsal and lateral palpal tibial setae (fPp = B/b/BbB vs. B/B/ NNB), presence of tibiala III, a lesser number of idiosomal setae (DS = 31–35 and V = 27–31 vs. 40–46 and 40, respectively), narrower scutum ( AW = 42–48 and PW = 49–55 vs. 52–55 and 68–72, respectively), shorter setae ( AM = 17–23, AL = 10–12, PL = 21–24, and H = 22–27 vs. 25–27, 20–23, 33–36, and 34, respectively), and by shorter legs (Ip = 473–531 vs. 632) ( Lakshana 1969).

Figures

FIGURE 8. Walchia dismina (Schluger, Grochovskaja, Ngu, Hoe and Tung, 1960), paralectotype ZMMU Tdt-3252 (specimen 2). A, dorsal aspect of idiosoma; B, ventral aspect of idiosoma. Cheladonta neda Schluger, Grochovskaja, Ngu, Hoe and Tung, 1960, additional material ZMMU XM14.63k1 (specimen 11). C, dorsal aspect of body; D, ventral aspect of body. Scale bars: 100 μm.

FIGURE 12. Cheladonta neda Schluger, Grochovskaja, Ngu, Hoe and Tung, 1960. A, arrangement of dorsal idiosomal setae of lectotype; B, arrangement of ventral idiosomal setae of lectotype; C, dorsal idiosomal seta of 1st row of additional material ZMMU XM14.63k1 (specimen 11); D, preanal seta of additional material ZMMU XM14.63k1 (specimen 11). Scale bars: 100 μm (A, B), 20 μm (C, D).

FIGURE 13. Cheladonta neda Schluger, Grochovskaja, Ngu, Hoe and Tung, 1960, additional material ZMMU XM14.63k1 (specimen 11). A, ventral aspect of gnathosoma; B, dorsal aspect of gnathosoma; C, leg I (trochanter–tarsus); D, leg II (trochanter–tarsus); E, leg III (trochanter–tarsus). Scale bars: 20 μm (A, B), 50 μm (C–E).

FIGURE 14. Type specimens of Cheladonta neda Schluger, Grochovskaja, Ngu, Hoe and Tung, 1960 on slides.

Tables

TABLE 5. Standard measurements (µm) and numbers of setae of Cheladonta neda (n = 6).

	Range	Mean	Lectotype
AW	42–48	45	46
PW	49–55	53	53
SB	17–21	19	21
ASB	15–19	16	16
PSB	13–16	14	15
SD	29–31	30	31
P-PL	5–10	7	10
AP	20–22	21	20
AM	17–23	20	21
AL	10–12	11	10
PL	21–24	23	24
H	22–27	25	27
D min	13–32	19	32
D max	22–26	24	25
V min	11–13	12	12
V max	17–20	18	18
pa	164–195	182	179
pm	141–162	152	141
pp	164–184	174	184
Ip	473–531	508	504
DS	31–35	34	34
V	27–31	29	31
NDV	61–66	63	65