Morelacarus camanchaca, Stekolnikov, Alexandr A. & González-Acuña, Daniel, 2015

Stekolnikov, Alexandr A. & González-Acuña, Daniel, 2015, A review of Chilean chiggers (Acari: Trombiculidae), with the description of a new genus and ten new species, Zootaxa 3964 (1), pp. 1-43 : 35-37

Morelacarus camanchaca sp. nov.

(Figs. 21, 22)

Diagnosis. SIF = 5B-B-3-2000.1000; fsp = 6.6.6; fCx = 2.1.1; fSt = 0.2; fPp = B/B/ BNN; fSc: PL = AL = AM; Ip = 617–630; fD = 2H-[6-4]-6-8-8(6)-4; DS = 36–38; VS = 19–22; NDV = 57–60. Standard measurements of type series given in Table 8 .

Description (larva). IDIOSOMA. Eyes 2 + 2, on ocular plate. One pair of humeral setae and 34–36 dorsal idiosomal setae covered with moderate barbs, arranged [6-4]-6-8-8(6)-4; 2 sternal setae between leg coxae III; 19– 22 ventral setae; total number of idiosomal setae excluding coxal and sternal 57–60; stigmae present between gnathocoxa and leg coxae I; tracheae poorly visible, traced up to posterior one-third of idiosoma.

GNATHOSOMA. Cheliceral blade with dorsal row of 4–5 teeth and 2 ventral teeth; gnathobase with few puncta, bears 1 pair of branched setae; palps without puncta; galeala branched; palpal claw with 3 prongs; setae on palpal femur and genu branched; dorsal palpal tibial seta branched; lateral and ventral palpal tibial setae nude; palpal tarsus with 5 branched setae and basal tarsala.

SCUTUM. Nearly subpentagonal, with nasus, few puncta, rounded posterior margin, 2 AM, 2 AL, and 2 PL setae; AM base at level of ALs; SB slightly posterior or at level of PLs (P-PL—PSB = 0–4); PL = AL = AM; flagelliform sensilla with 12–14 branches in distal half.

LEGS. All 6-segmented, with 1 pair of claws and claw-like empodium. Onychotriches present (1 cilium on each claw). Leg I: coxa with 2 non-specialized branched setae (2B); trochanter 1B; femur 6B; genu 4B, 2 genualae, microgenuala; tibia 8B, 2 tibialae, microtibiala; tarsus 24B, tarsala 6 long, microtarsala proximal to tarsala, pretarsala. Leg II: coxa 1B; trochanter 1B; femur 5B; genu 4B, microgenuala; tibia 6B, 2 tibialae; tarsus 17B, tarsala thin, 16 long, microtarsala distal to tarsala, pretarsala. Leg III: coxa 1B; trochanter 1B; femur 4B; genu 4B; tibia 6B; tarsus 14B, mastitarsala with 2–3 cilia in proximal half.

Host. Liolaemus platei Werner.

Type material. Holotype larva ( ZIN collection No. 8458, T-Tr.-75) ex L. platei No. IV 136 (27), CHILE: Coquimbo Region, Limarí Province, Fray Jorge National Park, 16 March 2011, coll. D. González-Acuña; 2 paratypes larvae (Nos. 8455 and 8457) with same data.

Etymology. “ Camanchaca ” is a Spanish word derived from the Aymaran “kamanchaka” (darkness), which means specific cloud banks characteristic for the region of Fray Jorge National Park.

FIGURE 21. Morelacarus camanchaca sp. nov. A, scutum and eyes (holotype); B, dorsal idiosomal seta of 1st row (holotype); C, preanal ventral idiosomal seta (holotype); D, dorsal aspect of gnathosoma; E, ventral aspect of gnathosoma; F, tarsus, tibia, and genu of leg I (holotype); G, tarsus, tibia, and genu of leg II (holotype); H, tarsus, tibia, and genu of leg III (holotype). Scale bars: 50 Μm (A, F–H), 20 Μm (B–E).

Remarks. The new species is similar to Morelacarus jorgei sp. nov. and differs from it in the presence of nude lateral and ventral palpal tibial setae (fPp = B/B/ BNN vs. B/B/BBB in M. jorgei ), presence of mastitarsala on leg tarsus III, lesser number of idiosomal setae (fD = 2H-[6-4]-6-8-8(6)-4 vs. [8-4]-6-8-8-4-2, DS = 36–38 vs. 42, VS = 19–22 vs. 23–29, and NDV = 57–60 vs. 65–71 in M. jorgei ), in shorter PLs and dorsal idiosomal setae (PL = 21 vs. 27–28, H = 23–24 vs. 30–32, and D max = 21–25 vs. 27–29), PL = AL = AM vs. PL> AL> AM, and in slightly more numerous branches of sensilla (12–14 vs. 8–10).

All above differences (except the last one) can be summarized as a lesser “hirsuteness” (i.e. lesser number of setae or branches of setae, or lesser length of setae) in M. camanchaca , as compared with M. jorgei . Thus, mastitarsala in M. camanchaca is homologous to an unspecialized tactile seta in M. jorgei , from which it differs in the lesser number of cilia and thin, whip-like distal part. Therefore, M. camanchaca could be an intraspecific form of M. jorgei ; its status should be clarified using more extensive material and possibly molecular methods.

The whole sample of Morelacarus collected in the Fray Jorge National Park, except 9 specimens of M. jorgei and 3 specimens of M. camanchaca , includes 6 unidentified specimens of poor quality ex L. platei No. IV 136 (27).