Neoschoengastia vietnamensis Kaluz

Kaluz, Stanislav, Hung, Nguyen Manh, Capek, Miroslav & Literak, Ivan, 2016, Two new species and new records of chiggers (Acari: Leeuwenhoekiidae, Trombiculidae) from birds in Vietnam, Zootaxa 4061 (5), pp. 483-503 : 491-496

Neoschoengastia vietnamensis Kaluz sp. nov.

( Figs. 6–9 )

Type material examined. Holotype: Location A: larva from Turdus cardis ( Passeriformes : Turdidae ), 4 February 2010. Paratypes: Location A: larva from Niltava davidi ( Passeriformes : Muscicapidae ), 1 February 2010; 14 larvae from Larvivora sibilans ( Passeriformes : Muscicapidae ), 5 February 2010; 2 larvae from Turdus cardis Passeriformes : Turdidae ), 1 February 2010; 12 larvae from Turdus cardis , 4 February 2010; 1 larva from Pellorneum ruficeps ( Passeriformes : Pellorneidae ), 1 February 2010.

Type depositions. Holotype and 10 paratypes are deposited in SNM; 10 paratypes in IEBR VAST; 10 paratypes in BMNH.

Etymology. The name of the new species is derived from the name of the country where we found type material of this chigger.

Description. Larva (n=12). SIF = 7B.S-B-3-3111.A000; fsp = 7-7-7; fPp = B.B.bBB; Ga = B; Pc = 3; fSc = AL> PL> AM; SB//PL; fCx = 1.1.1; fSt = 2.2; fD = 2H+8.6.6.4.4.2 = 32; DS = 32; VS = 28; NDV = 60; Ip = 869 (852–902).

Idiosoma ( Figs. 6 , 7 ). Scutum nearly as wide as long, bearing AM, AL, PL setae and distally expanded (rounded) sensilla (20 long, 18 wide). Posterior part of scutum partially submerged beneath the cuticular striae of dorsum. Posterior striae create concentric pattern in each of lateral halves of scutum. Anterior margin of scutum sinuous with “shoulders”, lateral margins conical with small medial protrusion. Scutal puncta spread and cover anterior and lateral parts of scutum. Scutal ridge present connecting both bases of sensilla. Rounded eyes (2 + 2) in ocular plate, anterior eye larger than posterior. Humeral setae 57 (54–61) long, dorsal setae 46 (43–51) long, arranged in regular rows, the posteriad rows varying in position of setae. Scutal measurements: AW 47 (46–49); PW 64 (63–67); SB 39 (36–42); ASB 19 (17–23); PSB 26 (20–29); SD 45 (37–51); P-PL 8 (6–10); AP 31 (29–34); AM 46 (43–51); AL 70 (62–78); PL 54 (51–59); S 20/18; fSc = AL> PL> AM. Sternal area with two pairs of sternal setae (fSt = 2.2), fCx = 1.1.1. Ventral side with 28 irregularly arranged ciliated setae. Lengths of ventral setae vary, increase from anterior 29 (26–32) to median 32 (29–36) and posterior 39 (36–43).

Gnathosoma ( Fig. 8 ). Galeala barbed (Ga = B). Palps 71 (67–82) long, palpotibial claw 21 (18–23) long with 3 deeply indented prongs. Chelicera anteriorly with tricuspid cap.

Legs ( Fig. 9 ). With pretarsus, claws and normal empodia. All setae on legs ciliated, slender. Specialized setae on leg segments—Leg I: Tarsus—S1 17, f1 3, nude pretarsala 11 (PT´= N), ciliated ST 32 and nude pST 20, 2 tibialae (anterior 20 and posterior 18), microtibiala 3, 3 genualae—anterior 17, median 23 and posterior 20, microgenuala 3; Leg II: Tarsus—nude pretarsala 11 (PT´´= N), S2 15, f2 3, 2 tibialae—anterior 16, posterior 16, genuala 17; Leg III: mastitarsala 56 (A-type; by Vercammen-Grandjean 1968) with 3–4 cilia, tibiala 17 and genuala 18. Number of barbed setae on leg segments (leg formula from coxa to tarsus): Leg I: 1-1- 1-5-4-8-20; Leg II: 1-1- 2 -4-3-5-16; Leg III: 1-1- 2 -3-3-5-14. Length of tarsi I–III: I—82 (80–83), II—65 (63–69), III—81 (78–84). Width of tarsi I–III: I—18 (17–20); II—17 (16–18); III—17 (16–17). Leg length: pa = 308 (301–320); pm = 264 (258– 274); pp = 297 (285–305); Ip = 869 (848–902).

Differential diagnosis. The new species is very morphologically close to Neoschoengastia posekanyi Wharton and Hardcastle, 1946 but differs by having Ga = B; AW 47 (46–49); PW 64 (63–67); SB 39 (36–42). Moreover, tarsus III bears A-type (branched in base) mastisetae and striae on the posterior part of the scutum are concentric. N. posekanyi differs from new species in having Ga = N; AW 75; PW 80; SB 47 and tarsus III with nude mastisetae. In this species parallel striae on the scutum are posteriorly horizontal. Another species close to the newly described species is Neoschoengastia heynemani Nadchatram and Upham,1966 . N. heynemani differs from Neoschoengastia vietnamensis sp. nov. by SIF = 7B.S-N-3-3111.0000, Ga = N, fPp = B.N.NNB, clavate but narrow apical part of sensillum and by lacking mastisetae on the tarsus III. Other differences are in the scutal formula (fSc: PL ≥ 2AM> AL) and length of leg III (pp. 263–270). On the contrary, Neoschoengastia vietnamensis sp. nov. has SIF = 7B.S-B-3-3111.A000; Ga = B, and fPp = B.B.NbB. The newly described species has also apically broad rounded sensilla, longer leg III (pp = 285–305) and fSc: PL> AM> AL, where PL is little longer than AM.

Figures

FIGURE 6. Neoschoengastia vietnamensis sp. nov. (holotype) — idiosoma dorsal. Scale bar: 100 µm.

FIGURE 7. Neoschoengastia vietnamensis sp. nov. (holotype) — idiosoma ventral. Scale bar: 100 µm.

FIGURE 8. Neoschoengastia vietnamensis sp. nov. (paratype) — gnathosoma (left—ventral, right—dorsal). Scale bar: 100 µm.

FIGURE 9. Neoschoengastia vietnamensis sp. nov. (paratype) — legs I – III (dots—bases of setae; filled dots—upper side; empty dots—bottom side. Numbers—lengths of solenidia and famuli. Scale bar: 100 µm.