Lorillatum attapinum ( Schluger, Grochovskaja, Ngu, Hoe and Tung, 1963 )

Stekolnikov, Alexandr A. & Antonovskaia, Anastasia A., 2021, Re-descriptions of eight chigger mite species (Acariformes: Trombiculidae) of the Leptotrombidium generic complex from Vietnam, Zootaxa 5057 (3), pp. 329-363 : 353-357

Lorillatum attapinum ( Schluger, Grochovskaja, Ngu, Hoe and Tung, 1963)

( Figs. 17–19 )

Trombicula attapina Schluger, Grochovskaja, Ngu, Hoe and Tung, 1963: 692 , figs. 8–15.

Lorillatum attapinum: Vercammen-Grandjean & Langston 1976: 947 ; Kudryashova 2004: 14; Stekolnikov 2021: 131 . Lorillatum attapina: Chau et al. 2007: 71 , figs. 33, 34.

Diagnosis. SIF = 7B-B-3-2111.0201; fsp = 7.7.7; fCx = 1.1.1; fSt = 2.2; fPp = B/N/NNb; fSc: PL> AM> AL; Ip = 924–1056; fD = 2H-[8-(1–3)]-10-10+18; DS = 51–56; V = 34–40; NDV = 87–91. Standard measurements of type series given in Table 7 .

Description (larva) (based on lectotype and 4 paralectotypes, fD recorded in one specimen). IDIOSOMA ( Figs. 17A , 18B–G ). Eyes 2 + 2; 51–56 barbed dorsal idiosomal setae, including one pair of humeral setae, 1 st posthumeral row (C except humeral setae) double, with 8 anterior and 3 posterior setae, 2 nd row (D) and 3 rd row (E) with 10 setae each plus 18 setae with unclear distribution by rows; 4 sternal setae; 34–40 ventral setae; NDV = 87–91.

GNATHOSOMA ( Fig. 19A, B ). Cheliceral blade with tricuspid cap; gnathobase densely covered with small puncta and bears 1 pair of branched gnathocoxal (tritorostral) setae; cheliceral base and palpal femur sparsely covered with puncta, palpal genu with few puncta; galeal (deutorostral) seta branched; palpal claw with 3 prongs; seta on palpal femur with few branches, seta on palpal genu nude, dorsal and lateral palpal tibial setae nude, ventral palpal tibial seta with one branch; palpal tarsus with 7 branched setae and tarsala (ω).

SCUTUM ( Figs. 17 , 18A ). Rectangular, densely covered with small puncta, with prominent anterolateral shoulders anterior to AL, anterior scutal margin concave, posterior margin bilobate; AM at level of AL, sensillary (trichobothrial) bases slightly anterior to level of PL (PSB – P-PL = 1–3 µm); all scutal setae barbed similarly to dorsal idiosomal setae; PL very long, pointed; PL> AM> AL; flagelliform sensilla (trichobothria) with one branch or nude.

LEGS ( Fig. 19C–J ).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 23B, tarsala (ω), microtarsala (ε) distal to tarsala, subterminala (ζ), parasubterminala (z), pretarsala (ζ). Leg II: coxa 1B; trochanter 1B; basifemur 2B; telofemur 4B; genu 3B, genuala; tibia 6B, 2 tibialae (φ); tarsus 16B, tarsala (ω) II shorter and slender than tarsala I, microtarsala (ε) posterior to tarsala, pretarsala (ζ). Leg III: coxa 1B; trochanter 1B; basifemur 2B; telofemur 2B and one very long flagelliform seta with few cilia in basal part; genu 3B, genuala; tibia 4B and two long flagelliform setae, nude or with few cilia, tibiala; tarsus 15B.

Distribution and hosts. This species was described from North Vietnam, Ha Giang Province, ex Crocidura sp. [= Crocidura leucrura (nomen nudum? lapsus calami?)] ( Schluger et al. 1963).

Type material examined. Lectotype larva ( ZMMU Tdt-3141, specimen 4, designated here) ex Crocidura sp. No 218, VIETNAM: Ha Giang Province, Ha Giang, 25 May 1956, coll. I.M. Grochovskaja. Three paralectotypes larvae ( ZMMU Tdt-3141, specimen 5; ZMMU Tdt-3140, specimens 1, 5) with same data as lectotype; one paralectotype larva ( ZMMU Tdt-3142, specimen 1) ex Crocidura sp. No 247, 1 June 1956, other data same as for lectotype.

Remarks. The genus Lorillatum includes 11 species distributed in Southeast and East Asia (Vercammen- Grandjean & Langston 1976; Li et al. 1997; Stekolnikov 2021). Lorillatum attapinum differs from all other species by the absence of palpal subterminala (ζ). Vercammen-Grandjean & Langston (1976), who did not see any material on this species, indicated the presence of the palpal subterminala in the diagnosis of L. attapinum obviously by a mistake. On the contrary, these authors did not notice the subterminala in L. mastigophorum ( Nadchatram, 1963) , as evident from their description and figures, although this seta is present according to the original description ( Nadchatram 1963). Lorillatum attapinum differs from L. mastigophorum , in addition to the absence of palpal subterminala, by the presence of one mastifemorala and two mastitibialae, vs. one mastifemorala, one mastigenuala, one mastitibiala, and one mastitarsala. However, stability of these characters is not evident, since the level of ciliation of mastisetae can vary at least in L. attapinum . Thus, Schluger et al. (1963) reported on the presence of one mastifemorala, one mastigenuala, and one mastitibiala in this species, but did not mention mastitarsala. Measurements and numbers of idiosomal setae in these species are very similar.

Lorillatum attapinum also shares its fPp = B/N/NNB(N) with L. kianjoei (Nadchatram and Traub, 1964) and L. panitae (Nadchatram and Traub, 1964) , but differs from L. kianjoei in having the greater number of idiosomal setae (DS = 51–56 and fD = 2H-[8-2]-10-… vs. 42–45 and 2H-8-8-…) and the presence of at most one mastigenuala vs. two, and from L. panitae in having shorter legs (Ip = 924–1056 vs. 1248), lesser number of idiosomal setae (two humeral setae vs. four, fD = 2H-[8-2]-10-… vs. 4H-[10-2]-13-…, NDV = 87–91 vs. 112), and rounded anterolateral shoulders of scutum vs. sharply angulate.

Figures

FIGURE 17. Lorillatum attapinum (Schluger, Grochovskaja, Ngu, Hoe and Tung, 1963). A, dorsal aspect of idiosoma in paralectotype ZMMU Tdt-3140, specimen 1 (left sensillum lost); B, scutum of lectotype. Scale bars: 50 μm.

FIGURE 18. Lorillatum attapinum (Schluger, Grochovskaja, Ngu, Hoe and Tung, 1963). A, scutum of paralectotype ZMMU Tdt-3141, specimen 1; B, humeral seta (C antero-marginal) of paralectotype ZMMU Tdt-3141, specimen 1; C, dorsal idiosomal seta of paralectotype ZMMU Tdt-3141, specimen 1; D, postanal seta of paralectotype ZMMU Tdt-3141, specimen 1; E, preanal seta of paralectotype ZMMU Tdt-3141, specimen 1; F, arrangement of dorsal idiosomal setae in paralectotype ZMMU Tdt- 3142, specimen 1; G, ventral aspect of idiosoma in paralectotype ZMMU Tdt-3142, specimen 1. Abbreviations as in Fig. 2. Scale bars: 50 μm (A–E), 100 μm (F, G).

FIGURE 19. Lorillatum attapinum (Schluger, Grochovskaja, Ngu, Hoe and Tung, 1963), lectotype. A, ventral aspect of gnathosoma (gnathocoxal seta detached); B, dorsal aspect of gnathosoma; C, leg I (genu–tarsus); D, leg I (trochanter–telofemur); E, leg II (trochanter–tarsus); F, leg III (genu–tarsus); G, leg III (trochanter–telofemur). Abbreviations as in Fig. 2. Scale bars: 50 μm (A, B), 50 μm (C–G).