Microtrombicula (Microtrombicula) zumpti Vercammen-Grandjean, 1965

Stekolnikov, Alexandr A., 2024, Revision of South African chiggers (Acariformes: Trombiculidae) originated from the collection of R. F. Lawrence, with redescriptions of nine species, Zootaxa 5493 (1), pp. 1-35 : 29-31

Microtrombicula (Microtrombicula) zumpti Vercammen-Grandjean, 1965

( Figs. 15C , 17 )

Microtrombicula (Microtrombicula) zumpti Vercammen-Grandjean, 1965a: 112 , pl. ZZ.

Microtrombicula zumpti : Vercammen-Grandjean 1965b: 45; Stekolnikov 2018: 176 .

Diagnosis. SIF = 6B-N-2-3111.1000; fPp = B/B/BN(B)B; AM = PL> AL; fD = 2H-[4-4]-6-4-4(6)+(4–8); DS = 30–32; V = 36–38; NDV = 68; scutum nearly quadrate, verrucose (scrobiculate), with weakly projected angulate posterior margin and anterolateral shoulders; sensillary bases far anterior to level of PLs; sensilla nude; posterior sternal setae and coxal setae II nude; Ip = 709–736. Standard measurements are given in Table 7 .

Redescription (two non-type specimens). IDIOSOMA ( Fig. 17A–H ). Eyes not observed; 30–32 dorsal idiosomal setae, including one pair of humeral setae, covered with small barbs, 8 setae in 1 st posthumeral row (C excluding humeral setae), 2 setae next to marginal shifted posteriad, 6 setae in 2 nd row (D), four setae in 3 rd row (E), four or six setae in 4 th row (F) plus 4–8 caudal setae; in specimen NM 5871/1 fD = 2H-[4-4]-6-4-4-4-4, in NM 5871/2 fD = 2H-[4-4]-6-4-6-2-2; 4 sternal setae, anterior pair with two branches, posterior pair nude; 36–38 ventral setae; NDV = 68.

GNATHOSOMA ( Fig. 17M, N ). Cheliceral blade with tricuspid cap and prominent dorsal tooth; cheliceral base and palpal femur with puncta, gnathobase with sparse puncta and one pair of branched gnathocoxal (tritorostral) setae; galeal (deutorostral) seta nude; palpal claw with two prongs; setae on palpal femur and genu branched; dorsal and ventral setae on palpal tibia branched; lateral palpal tibial seta nude; palpal tarsus with 6 non-specialized setae (dorsal seta thick, heavily branched, two ventral setae nude, other three setae branched) and tarsala (ω).

SCUTUM ( Figs. 15C , 17C ). Nearly quadrate, verrucose (scrobiculate), with weakly projected angulate posterior margin and anterolateral shoulders, anterior and lateral scutal margins almost straight, slightly concave; AM far anterior to level of ALs; sensillary (trichobothrial) bases far anterior to level of PLs (PSB – P-PL = 13); scutal setae uniform with dorsal idiosomal setae; AM = PL> AL; sensilla (trichobothria) flagelliform, nude.

LEGS ( Fig. 17O–Q ). All 7-segmented, with 1 pair of claws and claw-like empodium. Leg I: coxa with one seta bearing two branches (1B); trochanter 1B; basifemur 1B; telofemur 5B; genu 4B, 3 genualae (σ), microgenuala (κ); tibia 8B, 2 tibialae (φ), microtibiala (κ); tarsus 22B, tarsala (ω), microtarsala (ε) distal to tarsala, subterminala (ζ), parasubterminala (z), pretarsala (ζ). Leg II: coxa with one seta bearing one cilium or nude; trochanter 1B; basifemur 2B; telofemur 4B; genu 3B, genuala (σ); tibia 6B, 2 tibialae (φ); tarsus 16B, tarsala (ω), microtarsala (ε) behind tarsala, pretarsala (ζ). Leg III: coxa with one seta bearing two branches; trochanter 1B; basifemur 2B; telofemur 3B; genu 3B, genuala (σ); tibia 6B, tibiala (φ); tarsus 13B, mastitarsala.

Distribution and hosts. This species was described from Dargle, South Africa (KwaZulu-Natal Prov.), ex Procavia capensis . Here I report it ex Hystrix africaeaustralis Peters ( Rodentia : Hystricidae ) for the first time.

Material examined. Two larvae, NM 5871/1 and NM 5871/2, L:7256, ex ears of H. africaeaustralis, Matatiele, Natal , South Africa, 7 February 1956, coll. Lawrence, prepared by Vercammen-Grandjean ( Fig. 1 , 27) .

Remarks. This species was described from a single specimen (holotype) originally deposited in MRAC. I did not find the holotype neither in this museum ( Stekolnikov 2018), nor in the personal collection of Vercammen-Grandjean (Stekolnikov 2019). Its original description included only a brief diagnosis (diagnostic formulas), measurements, and the drawings of gnathosoma, scutum, idiosomal and coxal setae, tarsalae I and II, tarsus and tibia of leg III. The new material differs from the original description in fPp = B/B/BNB vs. B/B/BBB, sensilla nude vs. ciliated ( Vercammen-Grandjean 1965a, pl. ZZ, 9), shorter scutal setae (AM 37–39 vs. 46, AL 25–26 vs. 30, and PL 37–38 vs. 48), and less projected posterior scutal margin (PSB 27 vs. 32; see also pl. ZZ, 9 in the original description). Taking into account a small total number of specimens and a suboptimal quality of slides, I estimate these differences as insufficient to describe a new species.

Figures

FIGURE 1. Slide labels. 1, Microtrombicula homopholis, holotype; 2, Hypotrombidium subquadratum, holotype; 3, Willmannium natalense, lectotype; 4, W. natalense, paralectotype 1; 5, M. nivaria, paratype; 6, Herpetacarus (Abonnencia) alticolus, holotype; 7, H. (A.) alticolus, paratype; 8, H. (A.) alticolus, slide with topotypic specimens; 9, H. (A.) africanus, holotype; 10, H. (A.) africanus, topotypic specimen (ZIN label is on the opposite side); 11, H. (A.) longispinus, holotype; 12, H. (A.) longispinus, topotypic specimen (ZIN label is on the opposite side); 13, Ascoschoengastia rhabdomyia, slide NM 5387; 14, Riedlinia (Trombigastia) cadei, specimen NM 6544/3 (pencil inscription “/3” is mine; my identification label is on the opposite side); 15, Schoengastia pseudocordyli, slide NM 4939/1 (pencil inscriptions are mine; my identification label is on the opposite side); 16, S. scincicola, holotype; 17, S. scincicola, paratype NM 4870/2; 18, S. scincicola, paratype NHM 1957-8-12-35; 19, S. scincicola, non-type specimen (renounced paratype) NM 4870/3; 20, S. monticola, holotype; 21, S. monticola, paratype NHM 1957-8-12-34; 22, S. monticola, non-type specimen (renounced paratype) NM 4827; 23, S. monticola, specimen NM 4810/1 (pencil inscription “/1” is mine; my identification label is on the opposite side); 24, S. gerrhosauri, paratype NHM 1957-8- 12-36; 25, S. mabuyana, paratype NM 26422; 26, S. mabuyana, paratype NM 26423; 27, Microtrombicula (Microtrombicula) zumpti, specimen NM 5871/1 (pencil inscriptions are mine; my identification label is on the opposite side); 28, Neotrombicula (Anamasticula) rhodesiana, holotype.

FIGURE 15. Schoengastia gerrhosauri Lawrence, 1949, paratype NHM 1957-8-12-36 (A), Schoengastia mabuyana Lawrence, 1949, paratype NM 26422 (B), Microtrombicula (Microtrombicula) zumpti Vercammen-Grandjean, 1965, specimen NM 5871/1 (C), Neotrombicula (Anamasticula) rhodesiana (Lawrence, 1949), holotype (D). Dorsal aspect of idiosoma (A, B), scutum (C, D). Scale bars: 50 µm.

FIGURE 17. Microtrombicula (Microtrombicula) zumpti Vercammen-Grandjean, 1965, specimens NM 5871/2 (A, B) and 5871/1 (C–Q). A, dorsal aspect of idiosoma; B, arrangement of ventral idiosomal setae; C, scutum (eyes invisible); D, humeral seta; E, dorsal idiosomal seta; F, preanal seta; G, anterior sternal seta; H, posterior sternal seta; I, coxal seta I; J, K, coxal setae II; L, coxal seta III; M, dorsal aspect of gnathosoma; N, ventral aspect of gnathosoma; O, leg I, trochanter–tarsus; P, leg II, trochanter–tarsus; Q, leg III, trochanter–tarsus.Abbreviations as in Fig. 9. Scale bars: 100 µm (A, B), 50 µm (C), 20 µm (D–L), 20 µm (M, N), 50 µm (O–Q).