Microtrombicula mapuche, 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 : 12-14

Microtrombicula mapuche sp. nov.

(Fig. 7)

Diagnosis. SIF = 6B-N-3-2111.1000; fsp = 7.7.7; fCx = 1.1.1; fSt = 2.2; fPp = B/B/BNB; fSc: PL = AL = AM; Ip = 619–652; fD = 2H-8-6-6-4-2; DS = 26–30; VS = 18–23; NDV = 46–51. Standard measurements of holotype: AW 59, PW 78, SB 26, ASB 20, PSB 23, SD 43, P-PL 25, AP 19, AM 18, AL 22, PL 20, S 46, H 25, D min 18, D max 23, V min 18, V max 22, pa 223, pm 185, pp 218, Ip 626, DS 28, VS 21, NDV 49, TaIIIL 54, TaIIIW 13, m-t 0.317. Standard measurements of type series given in Table 2 .

Description (larva). IDIOSOMA. Eyes 2 + 2, on ocular plate, anterior larger. One pair of humeral setae, 24– 28 short dorsal idiosomal setae with 3 longitudinal rows of rather long barbs, fD = 2H-8-6-6-4-2, with a little variation; 4 sternal setae; 18–23 ventral setae; total number of idiosomal setae excluding coxal and sternal 46–51.

GNATHOSOMA. Cheliceral blade with tricuspid cap; cheliceral base with dense puncta in proximal part; gnathobase with dense puncta in posterior part and few puncta in anterior part, with 1 pair of branched setae; galeala nude; palpal claw with 3 prongs; seta on palpal femur branched; seta on palpal genu with few (at least 1) branches; dorsal palpal tibial seta with few branches, lateral palpal tibial setae nude, ventral palpal tibial seta branched; palpal tarsus with 6 branched setae and basal tarsala.

SCUTUM. Clearly pentagonal, with acute posterior margin, moderately covered by puncta; AM base posterior to level of ALs; SB at level or slightly posterior to level of PLs (P-PL—PSB = 0–4); PL = AL = AM; flagelliform sensilla with 8–12 short branches in distal half.

LEGS. All 7-segmented, with 1 pair of claws and claw-like empodium. Leg I: coxa with 1 non-specialized branched seta (1B); trochanter 1B; basifemur 1B; telofemur 5B; genu 3B, 2 genualae, microgenuala; tibia 8B, 2 tibialae, microtibiala; tarsus 22B, tarsala 12 long, microtarsala distal 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 thin, 12 long, microtarsala proximal to tarsala, pretarsala. Leg III: coxa 1B; trochanter 1B; basifemur 2B; telofemur 3B; genu 3B, genuala; tibia 6B, tibiala; tarsus 14B, mastitarsala nude or with 1 cilium.

Host. Liolaemus chillanensis Müller and Hellmich.

Type material. Holotype larva ( ZIN collection No. 7702, T-Tr.-69) ex Liolaemus chillanensis No. 9, CHILE: Biobío Región, Nevados de Chillán Mts, tourist camp Waldorf (36°51′41″ S, 71°26′45″ W), altitude 1930 m a.s.l., 11 January 2006, coll. D. González-Acuña; 3 larvae paratypes (7700, 7701, 7703) with same data; 10 larvae paratypes (7718–7727) ex L. chillanensis Nos. 13 and 14, 10 January 2007, other data same.

Etymology. The species is named after the Mapuche people, an ethnic group of indigenous inhabitants of south-central Chile.

Remarks. The new species is similar to Microtrombicula phyllodactyli Webb and Loomis, 1970 and M. guaurabensis Daniel and Stekolnikov, 2006 , but differs from both these species in fPp = B/B/BNB vs. B/B/NNB, fD = 2H-8-6-6-4-2 vs. 2H-6-6-6-4-2-(2), 2 genualae I vs. 3, wider scutum (AW = 53–59 vs. 45–51, PW = 70–78 vs. 59–66, SB = 23–28 vs. 17–21), and in longer legs (Ip = 619–652 vs. 508–556 in M. phyllodactyli and 569–612 in M. guaurabensis ).

FIGURE 7. Microtrombicula mapuche sp. nov. A, scutum and eyes (holotype); B, arrangement of dorsal idiosomal setae; C, arrangement of ventral idiosomal setae; D, dorsal aspect of gnathosoma (cheliceral blade is lost); E, cheliceral blade; F, ventral aspect of gnathosoma; G, tarsus, tibia, and genu of leg I; H, tarsus, tibia, and genu of leg II; I, tarsus, tibia, and genu of leg III; J, dorsal idiosomal seta of 1st row (holotype); K, preanal ventral idiosomal seta (holotype). Scale bars: 50 Μm (A, G, H, I), 100 Μm (B, C), 20 Μm (D–F, J, K).

Tables

TABLE 2. Standard measurements of Microtrombicula mapuche sp. nov.

Variable	Range	Mean	Sample size
AW	53–59	56	9
PW	70–78	74	9
SB	23–28	25	9
ASB	20–23	22	9
PSB	22–26	23	9
SD	42–48	45	9
P-PL	24–28	26	9
AP	17–21	19	9
AM	16–20	19	9
AL	18–22	20	9
PL	18–22	20	9
S	44–48	46	7
H	22–25	23	9
D min	16–20	18	9
D max	20–25	23	9
V min	16–18	17	3
V max	20–22	21	3
pa	223–234	229	6
pm	176–198	191	6
pp	214–225	220	6
Ip	619–652	639	6
DS	26–30	28	9
VS	18–23	21	9
NDV	46–51	49	9
TaIIIL	52–58	55	9
TaIIIW	12–13	13	9
m-t	0.241–0.317	0.275	9