Leptotrombidium pilosum cambodiensis, Antonovskaia & Morand & Stekolnikov, 2024

Antonovskaia, Anastasia A., Morand, Serge & Stekolnikov, Alexandr A., 2024, New species and new records of chigger mites (Acariformes, Trombiculidae) from Cambodia, Zootaxa 5406 (2), pp. 343-358 : 346-349

Leptotrombidium pilosum cambodiensis subsp. nov.

( Figs. 1C, D , 4 , 5 )

Diagnosis. SIF = 7B-B-3-2111.0000; fPp = B/B/BBB; fSc: AM ≥ PL> AL; SB/PL; fCx = 1.1.1; fSt = 2.2; Ip = 762–855; fD = (2–4)H-(9–17)-(9–10)-(7–10)-(4–7)-(2–4)-(1–3); DS = 38–49; V = 34–45; NDV = 76–89. Standard measurements are in Table 2.

Description (larva). IDIOSOMA ( Figs. 1C, D , 4B–G ). Eyes 2+2, on ocular plate; 38–49 moderately barbed dorsal idiosomal setae, including 2–4 humeral setae; 9–17 setae in 1 st post-humeral row (C excluding humeral setae), 9–10 setae in 2 nd row (D), 7–10 setae in 3 rd row (E), 4–7 setae in 4 th row (F); 4 sternal setae and 34–45 ventral setae; total number of idiosomal setae excluding coxal and sternal 76–89.

GNATHOSOMA (5A–C). Cheliceral blade with tricuspid cap; cheliceral base and palpal femur moderately covered with puncta; gnathobase with dense puncta and one pair of branched gnathocoxal (tritorostral) setae; galeal (deutorostral) seta heavily branched; palpal claw with three prongs; all setae on palps branched; palpal tarsus with seven branched setae and basal tarsala (ω).

SCUTUM (1D, 4A). Rectangular, moderately covered with puncta, with posterior margin rounded; AM base posterior to level of ALs; SB slightly anterior to level of PLs (PSB – P-PL= 2–5, mean 3); AM ≥ PL> AL; scutal setae barbed similarly to dorsal idiosomal setae; flagelliform sensilla (trichobothria) basally nude, with 7–11 cilia in middle part and 7–11 branches distally.

LEGS (5D–F).All 7-segmented, with pair of claws and claw-like empodium. Leg I: coxa with 1 non-specialized branched seta (1B); trochanter 1B; basifemur 1B; telofemur 5B; genu 4B, 2 genualae (σ), microgenuala (κ); tibia 8B, 2 tibialae (φ), microtibiala (κ); tarsus 22B, tarsala (ω) (18–19 long), microtarsala (famulus, ε) distal of tarsala, subterminala (ζ), parasubterminala (z), pretarsala (ζ). Leg II: coxa 1B; trochanter 1B; basifemur 2B; telofemur 4B; genu 3B, genuala (σ); tibia 6B, 2 tibialae (φ); tarsus 16B, tarsala (ω) (14–16 long), microtarsala (famulus, ε) behind tarsala, pretarsala (ζ). Leg III: coxa 1B; trochanter 1B; basifemur 2B; telofemur 2B; genu 3B, genuala (σ); tibia 5B, tibiala (φ); tarsus 15B.

Type material. Larval holotype ( ZIN 14241 , L-525) ex B. savilei No. C 0683, CAMBODIA, Mondulkiri Province, Keo Seima , 23 November 2009; nine larval paratypes ( ZIN 14194 , 14204 , 14208 , 14212 , 14213 , 14219 , 14223 , 14227 , 14251 ) with same data .

Etymology. The name of subspecies refers to the name of the country, Cambodia.

Differential diagnosis. The species Leptotrombidium pilosum Traub and Lakhana, 1966 is unique within the genus Leptotrombidium in having all palpal setae branched (fPp = B/B/BBB). The new subspecies differs from the nominative subspecies, L. pilosum pilosum , in the arrangement of dorsal idiosomal setae. The first post-humeral row is simple in the new subspecies and double in the nominative subspecies; 2 nd row consists of 9–10 setae vs. 6–8 in L. pilosum pilosum . The double 1 st row was interpreted by the authors of the original description ( Traub & Lakshana 1966) as merged 1 st and 2 nd rows. We do not agree with this homology, since the number and configuration of posterior rows in both subspecies of L. pilosum are the same and coincide with those in other species of Leptotrombidium .

Figures

FIGURE 1. Leptotrombidium mondulkiri sp. nov., holotype. A—anterior part of idiosoma, dorsal aspect; B—sternal area, ventral aspect. Leptotrombidium pilosum cambodiensis subsp. nov., paratype ZIN 14251. C—anterior part of idiosoma, dorsal aspect; D—sternal area. Scale bars: 100 µm.

FIGURE 4. Leptotrombidium pilosum cambodiensis subsp. nov., paratype ZIN 14199 (A–E), holotype (F, G). A—scutum; B—humeral seta; C—dorsal idiosomal seta; D—postanal seta; E—preanal seta; F—arrangement of dorsal idiosomal setae; G—arrangement of ventral idiosomal setae. Abbreviations as in Figure 2. Scale bars: 50 μm (A–E), 100 μm (F, G).

FIGURE 5. Leptotrombidium pilosum cambodiensis subsp. nov., paratype ZIN 14225 (A–C), paratype ZIN 14217 (D–F). A— ventral aspect of gnathosoma; B—dorsal aspect of gnathosoma; C—palpal claw; D—leg I; E—leg II; F—leg III. Abbreviations as in Figure 3. Scale bars: 20 µm (A–C), 100 µm (D–F).