(Figs. 16–18)
Diagnosis. SIF = 7 B-N- 3 -1111.0000; fsp = 7.7.7; fCx = 1.1.1; fSt = 2.2; fPp = B/B/BNB; fSc: PL> AL >> AM; Ip = 972–1051; fD = 2 H-[(10–16)-(11–21)]-[(10–17)-(5–11)]-(9–16)-…; DS = 73–96; VS = 45–55; NDV = 118–148. Standard measurements of type series given in Table 6.
Description (larva). IDIOSOMA. Eyes 2 + 2, on ocular plate. One pair of humeral setae, 73–96 dorsal idiosomal setae covered with moderate barbs, with variable arrangement by rows, first 2 rows double, first row in some specimens appears triple, in holotype fD = 2 H-[12-18]-[10 - 9]- 12-13 - 4; 4 sternal setae; 45–55 ventral setae; total number of idiosomal setae excluding coxal and sternal 118–148.
GNATHOSOMA. Cheliceral blade with tricuspid cap; gnathobase densely covered with puncta and bears 1 pair of branched setae; palpal femur with sparse puncta; galeala nude; palpal claw with 3 prongs; seta on palpal femur branched; seta on palpal genu with 1 or 2 branches; dorsal and ventral palpal tibial setae branched; lateral palpal tibial seta nude; palpal tarsus with 7 branched setae and basal tarsala.
SCUTUM. Nearly hexagonal, densely covered with small puncta; AM base clearly posterior to level of ALs; SB at level or slightly posterior to level of PLs (P-PL—PSB = 0–5); PL> AL >> AM; sensilla clavate, densely covered with large barbs on one side and with few barbs on other side.
FIGURE 16. Proschoengastia antarctica sp. nov. A, scutum and eyes; B, arrangement of dorsal idiosomal setae; C, arrangement of ventral idiosomal setae; D, dorsal idiosomal seta of 1 st row; E, preanal ventral idiosomal seta. Scale bars: 50 Μm (A), 100 Μm (B, C); 20 Μm (D, E).
LEGS. All 7 -segmented, with 1 pair of claws and claw-like empodium. Leg I: coxa with 1 non-specialized branched seta (1 B); trochanter 1 B; basifemur 1 B; telofemur 5 B; genu 4 B, 1 genuala, microgenuala; tibia 8 B, 2 tibialae, microtibiala; tarsus 22 B, tarsala 15 long, microtarsala slightly distal to tarsala, subterminala, parasubterminala, pretarsala. Leg II: coxa 1 B; trochanter 1 B; basifemur 2 B; telofemur 4 B; genu 3 B, genuala; tibia 6 B, 2 tibialae; tarsus 16 B, tarsala thin, 14 long, microtarsala near tarsala, pretarsala. Leg III: coxa 1 B; trochanter 1 B; basifemur 2 B; telofemur 3 B; genu 3 B, genuala; tibia 6 B, tibiala; tarsus 15 B.
Host. Neovison vison (Schreber).
Type material. Holotype larva (ZIN collection No. 8483, T-Tr.- 73) ex Neovison vison No. 21, CHILE: Region of Magallanes and Antártica Chilena, Antártica Chilena Province, Navarino Island, 26 February 2011, coll. José Cabello; 11 paratypes larvae (Nos. 8479–8490) with same data.
Etymology. The species epithet refers to the Province of Chilean Antarctica (Antártica Chilena), where the type locality is situated, and indicates that this species is found closer to the continent of Antarctica than all other chiggers.
Remarks. The new species is similar to Proschoengastia macrochaeta and differs from it in microtarsala (f 1) anterior to tarsala (S 1) vs. posterior, f 2 near to S 2 vs. posterior, in slightly lesser scutum (AW = 77–86 vs. 88, PW = 104–113 vs. 121, and PSB = 20–23 vs. 25), shorter scutal setae (AM = 40–49 vs. 67, AL = 81–101 vs. 130, and PL = 88–103 vs. 108), and in much more numerous idiosomal setae (DS = 73–96 vs. 42 and VS = 45–55 vs. 34).