Herpetacarus (Abonnencia) longispinus ( Radford, 1948 )

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 : 11-14

Herpetacarus (Abonnencia) longispinus ( Radford, 1948)

( Figs. 5A, B , 6 )

Ascoschoengastia longispina Radford, 1948: 219 , figs. 13–14.

Euschoengastia longispina : Wharton & Fuller 1952: 78; Zumpt 1961: 162.

Herpetacarus (Abonnencia) longispina : Vercammen-Grandjean 1965b: 87; 1966: 643, pl. O, 3.

Herpetacarus (Abonnencia) longispinus : Stekolnikov 2018: 61 .

Ascoschoengastia rhabdomyia Lawrence, 1951a: 116 , fig. 16, c, syn. nov.

Euschoengastia rhabdomyia : Wharton & Fuller 1952: 81; Zumpt 1961: 162.

Herpetacarus (Herpetacarus) rhabdomys : Vercammen-Grandjean 1965b: 86; Stekolnikov 2018: 68 .

Herpetacarus (Herpetacarus) rhabdomiya : Vercammen-Grandjean 1966: 640, pl. F, 5.

Diagnosis. SIF = 7B-N-3-2111.1100; fPp = B/B/NNB; PL ≥ AL >> AM; fD = 2H-8-6-6-6+(2–8); DS = 30–34; V = 21–24; NDV = 53–55; scutum telostigmal, with bow-shaped posterior margin; sensilla subglobose; sensillary bases anterior to level of PLs; Ip = 731–820. Standard measurements are given in Table 3 .

Redescription (holotype and 1 topotypic specimen of H. longispinus and 8 non-type specimens of A. rhabdomyia ). IDIOSOMA ( Figs. 5A, B , 6A–F ). Eyes 2 + 2, in ocular plate; 30–34 dorsal idiosomal setae, including one pair of humeral setae, moderately covered with thin barbs, 8 setae in 1 st posthumeral row (C excluding humeral setae), by 6 setae in next three rows plus 2–8 caudal setae; 4 sternal setae; 21–24 ventral setae; NDV = 53–55.

GNATHOSOMA ( Fig. 6G, H ). Cheliceral blade with tricuspid cap and dorsal tooth; cheliceral base, gnathobase, palpal femur and genu with puncta; gnathobase with 1 pair of branched gnathocoxal (tritorostral) setae; galeal (deutorostral) seta nude; palpal claw with three prongs; setae on palpal femur and genu branched; dorsal and lateral setae on palpal tibia nude; ventral palpal tibial seta branched; palpal tarsus with 7 branched setae and tarsala (ω).

SCUTUM ( Figs. 5A, B , 6C, D ). Nearly trapezoidal, telostigmal, moderately covered with small puncta, anterior scutal margin sinuous, lateral margins slightly concave, posterior margin slightly projected, bow-shaped; ALs and PLs situated in projected angles of scutum; AM posterior to level of ALs; sensillary (trichobothrial) bases anterior to level of PLs (PSB – P-PL = 3–8); all scutal setae uniform with dorsal idiosomal setae; PL ≥ AL >> AM; sensilla (trichobothria) subglobose, covered with small setules.

LEGS ( Fig. 6I–K ). All 7-segmented, with 1 pair of claws and claw-like empodium. Leg I: coxa with 1 branched seta (1B); trochanter 1B; basifemur 1B; telofemur 5B; genu 4B, 2 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 1B; trochanter 1B; basifemur 2B; telofemur 3B; genu 3B, genuala (σ); tibia 6B, 2 tibialae (φ); tarsus 16B, tarsala (ω), microtarsala (ε) behind tarsala, pretarsala (ζ). Leg III: coxa 1B; trochanter 1B; basifemur 2B; telofemur 3B; genu 3B, genuala (σ); tibia 5B, tibiala (φ), mastitibiala; tarsus 14B, mastitarsala.

Distribution and hosts. This species was described from Glen Craig, Grahamstown (currently Makhanda, Eastern Cape), South Africa, ex Aethomys namaquensis (A. Smith) (syn. Thallomys namaquensis grahami Roberts ) ( Rodentia : Muridae ). Ascoschoengastia rhabdomyia was described from Champagne Castle, Drakensberg Mts., Natal, South Africa, ex Rhabdomys pumilio ( Rodentia : Muridae ) and Procavia capensis capensis (Pallas) (syn. P. c. natalensis Roberts ) ( Hyracoidea : Procaviidae ).

Material examined. Holotype larva of Ascoschoengastia longispina, NHM 1948 -2-3-31, ex Thallomys n. grahami, Grahamstown, Glen Craig, 24 May 1939, Dr. G. Theiler ( Fig. 1 , 11 ). Topotypic larva of A. longispina , labeled as Euschoengastia longispina (Radford) , ZIN 14503, ex Thallomys n. grahami, Grahamstown, Glen Craig, 24 May 1939, G. Theiler ( Fig. 1 , 12 ). Eight non-type specimens, larvae of A. rhabdomyia on two slides (NM 5387 and 5388), ex P. c. natalensis, P’Maritzburg (Pietermaritzburg, KwaZulu-Natal Prov.) , February 1951, collector unknown ( Fig. 1 , 13 ).

Remarks. As in the case of H. alticolus, Vercammen-Grandjean (1965b , 1966) followed by Stekolnikov (2018) included H. rabdomyia in the subgenus Herpetacarus (Herpetacarus) without examination of any material. However, the absence of palpal subterminala (ζ) shows that this species should belong to the subgenus Herpetacarus (Abonnencia) .

The examined specimens of A. rhabdomyia differ from the holotype of A. longispina only in a slightly lesser size ( Table 3 ). Thus, identity of these two species is indubitable and I regard A. rhabdomyia as a synonym of H. longispinus .

This species is similar to Herpetacarus (Abonnencia) aethomys (Radford, 1942) and differs from it in nude dorsal palpal tibial seta vs. branched (fPp = B/B/NNB vs. B/B/BNB), bow-shaped posterior scutal margin vs. evenly arquate, shorter scutum (PSB = 16–20 vs. 25; SD = 41–45 vs. 56), and in a slightly higher number of idiosomal setae (NDV = 53–57 vs. 50) ( Vercammen-Grandjean 1966).

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 5. Herpetacarus (Abonnencia) longispinus (Radford, 1948), holotype (A), Ascoschoengastia rhabdomyia Lawrence, 1951, specimen NM 5387, left on the slide (B), Riedlinia (Trombigastia) cadei (Vercammen-Grandjean and Brennan, 1957), specimen NM 6544/3 (C). Dorsal aspect of idiosoma. Scale bars: 50 µm.

FIGURE 6. Ascoschoengastia rhabdomyia Lawrence, 1951, specimen NM 5387, third from right on the slide. A, dorsal aspect of idiosoma; B, arrangement of ventral idiosomal setae; C, scutum and eyes (sensilla missing); D, sensillum; E, dorsal idiosomal seta; F, preanal idiosomal seta; G, dorsal aspect of gnathosoma; H, ventral aspect of gnathosoma; I, leg I, trochanter–tarsus; J, leg II, trochanter–tarsus; K, leg III, trochanter–tarsus. Abbreviations as in Figs. 3 and 4. Scale bars: 100 µm (A, B), 50 µm (C, D), 20 µm (E, F), 20 µm (G, H), 50 µm (I–K).

FIGURE 11. Schoengastia scincicola Lawrence, 1949, holotype (C, E–G), paratype NM 4870/2 (A, B, D, J–L), specimen NM 4870/3 (H, I). A, dorsal aspect of idiosoma; B, arrangement of ventral idiosomal setae; C, scutum and eyes (setules of sensillum invisible); D, sensillum; E, dorsal idiosomal seta; F, preanal idiosomal seta; G, cheliceral blades and galeal (deutorostral) seta; H, ventral aspect of gnathosoma (gnathocoxa split, cheliceral blades missing, galeal seta invisible, terminal seta on palpal tarsus broken); I, dorsal aspect of gnathosoma; J, leg I, trochanter–tarsus; K, leg II, trochanter–tarsus; L, leg III, trochanter–tarsus. Abbreviations as in Fig. 9. Scale bars: 100 µm (A, B), 50 µm (C, D), 20 µm (E, F), 20 µm (G–I), 50 µm (J–L).

FIGURE 12. Schoengastia monticola Lawrence, 1949, holotype. A, dorsal aspect of idiosoma; B, scutum. Scale bars: 50 µm.

FIGURE 13. Schoengastia monticola Lawrence, 1949, holotype. A, dorsal aspect of idiosoma; B, arrangement of ventral idiosomal setae; C, scutum and eyes; D, humeral seta; E, preanal seta; F, G, dorsal idiosomal setae. Abbreviations as in Fig. 2. Scale bars: 100 µm (A, B), 50 µm (C), 20 µm (D–G).