Herpetacarus (Herpetacarus) junkeri, Stekolnikov, 2018

Stekolnikov, Alexandr A., 2018, African chiggers (Acariformes: Trombiculidae) in the collection of Alex Fain, with a description of a new genus and three new species, Acarologia 58 (2), pp. 265-286 : 271-274

Herpetacarus (Herpetacarus) junkeri n. sp. ( Figures 1-2 )

Zoobank: 8CA6F6DB-F04A-4C6C-A063-7DE803AD3A4D

Diagnosis — SIF = 7BS-N-3-3111.0000; fsp = 7.7.7; fCx = 1.1.1; fSt = 2.2; fPp = B/N/NNN; fSc: PL> AM> AL; Ip = 885 – 943; fD = 2H-10(11)-10-6(7)-2-4-…; DS = 34 – 40; VS = 29 – 36; NDV = 69 – 71. Standard measurements of type series are given in Table 2.

Description (larva)

Idiosoma — Eyes not visible in all specimens examined. One pair of humeral setae, 32 – 38 dorsal idiosomal setae arranged 10(11)-10-6(7)-2-4-…, in holotype 10-10-6-2-4; four sternal setae; 29 – 36 ventral setae; total number of idiosomal setae excluding coxal and sternal 69 – 71. Humeral, caudal, ventral postanal, anterior sternal and coxal setae I-II with sparse long barbs; dorsal idiosomal setae with bulbous base and sparse long barbs; posterior sternal, preanal ventral and coxal setae III very short, with bulbous base, their barbs broken in all specimens examined.

Gnathosoma — Cheliceral blade with tricuspid cap; cheliceral base with one lateral and one dorsal angular projection; gnathobase with one pair of branched setae, series of transverse folds and sparse puncta (puncta not visible in holotype); galeal setae nude; palpal claw with 3 prongs; palpal femoral seta with few branches, palpal genual and tibial setae nude; palpal tarsus with 7 branched setae, nude subterminala, and basal tarsala.

Scutum — Nearly hexagonal, much wider than long, with concave anterior margin, with longitudinal cracks in all specimens examined, with small puncta, posterior margin almost straight medially; AM situated far posterior to level of ALs; SB situated posterior to level of PLs (P-PL – PSB = 2 – 5); PL> AM> AL; AM and ALs similar to caudal idiosomal setae, PLs similar to dorsal idiosomal setae, with bulbous base; sensilla slightly expanded, fusiform, 3 – 4 μm wide, covered by long barbs.

Legs — All legs 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, 3 genualae, microgenuala; tibia 8B, 2 tibialae, microtibiala; tarsus 21B, tarsala elongated (38 μm), extends far beyond the base of subterminala, 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 18 long, microtarsala behind tarsala, pretarsala. Leg III: coxa 1B; trochanter 1B; basifemur 2B; telofemur 3B; genu 3B, genuala; tibia 6B, tibiala; tarsus 15B.

Host — Boaedon fuliginosus (Boie) ( Squamata : Colubridae ).

Type material — larva holotype (IRSNB) under ventrolateral scales of B. fuliginosus, DR CONGO, Nord-Ubangi Province, Bosobolo, 4°11′23′′N, 19°53′00′′E, 2 Jul. 1955 (1956?), collected by A. Fain; 2 larvae paratypes with same data .

Etymology — The species named after Wilhelm Junker (1840-1892), a famous Russian explorer of Africa.

Differential diagnosis — The new species is similar to Herpetacarus (Herpetacarus) aspidelaps Vercammen-Grandjean, 1966 and differs from it in PLs having bulbous base and in larger number of idiosomal setae [fD = 2H-10(11)-10-6(7)-2-4-…, DS = 34 – 40, VS = 29 – 36, and NDV = 69 – 71 vs. fD = 2H-8-6-6-4-4, DS = 30, VS = 22, and NDV = 52 in H. aspidelaps]. Scutal measurements in the new species are also larger, but it could be caused by a deformation of scutum in all specimens examined, due to numerous small cracks. Shape of setae was not described for H. aspidelaps , but according to figures, at least setae on coxae III and ventral setae have bulbous bases in this species, while PLs are similar to ALs and AM.

The new species differs from another species having setae with bulbous bases, H. causicolus , in the absence of mastitarsala, less expanded sensilla (3 – 4 vs. 4 – 7 μm wide), different formula of dorsal idiosomal setae [fD = 2H-10(11)-10-6(7)-2-4-… vs. fD = 2H-8-8(6)-6-4-… in H. causicolus], PL> AM vs. AM>= PL, SB situated posterior to level of PLs vs. anterior to level of PLs (P-PL – PSB = 2 – 5 vs. PSB – P-PL = 2 – 4), longer setae (PL = 65 – 68, H = 65 – 69, Dmax = 62 – 65, and Vmax = 61 – 62 vs. 44 – 51, 52 – 59, 41 – 51, and 42 – 49, respectively), and in longer legs (Ip = 885 – 943 vs. 812 – 882).

Figures

Figure 1 Herpetacarus junkeri n. sp., larva: A – scutum; B – humeral seta; C – dorsal idiosomal seta ofnd2 row; D – ventral postanal idiosomal seta; E – ventral preanal idiosomal seta; F – anterior sternal seta; G – arrangement of dorsal idiosomal setae; H – arrangement of ventral idiosomal setae (excretore pore invisible). Scale bars: A – 50 μm; B-F – 20 μm; G-H – 200 μm.

Figure 2 Herpetacarus junkeri n. sp., larva: A – dorsal aspect of gnathosoma; B – ventral aspect of gnathosoma; C – cheliceral blade; D – tarsus, tibia, and genu of leg I; E – tarsus, tibia, and genu of leg II; F – tarsus, tibia, and genu of leg III. Scale bars: A-C – 20 μm; D-F – 50 μm.