Proschoengastia antarctica Stekolnikov & González-Acuña, 2015, sp. nov.

Proschoengastia antarctica sp. nov.

(Figs. 16–18)

Diagnosis. SIF = 7B-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 = 2H-[(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 = 2H-[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 1st 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 (1B); trochanter 1B; basifemur 1B; telofemur 5B; genu 4B, 1 genuala, microgenuala; tibia 8B, 2 tibialae, microtibiala; tarsus 22B, tarsala 15 long, microtarsala slightly 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, 14 long, microtarsala near tarsala, pretarsala. Leg III: coxa 1B; trochanter 1B; basifemur 2B; telofemur 3B; genu 3B, genuala; tibia 6B, tibiala; tarsus 15B.

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 (f1) anterior to tarsala (S1) vs. posterior, f2 near to S2 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).