Eutrombicula pacae ( Floch and Fauran, 1957 )

Stekolnikov, Alexandr A., Capek, Miroslav & Literák, Ivan, 2022, New species and records of chiggers (Acariformes: Trombiculidae) from birds of the Neotropics, Zootaxa 5141 (6), pp. 501-552 : 525-527

Eutrombicula pacae ( Floch and Fauran, 1957)

( Figs. 16–18 )

Trombicula (Eutrombicula) pacae Floch and Fauran, 1957: 1 , fig. 1.

Eutrombicula pacae: Brennan & Reed 1974: 710 ; Loomis & Wrenn 1984: 158; Stekolnikov et al. 2007: 65.

Diagnosis. SIF = 7BS-N-2-3111.1000; fsp = 7.7.7; fCx = 1.1.1; fSt = 2.2; fPp = B/B(N)/NNN; fSc: PL ≥ AM> AL; Ip = 764–810; fD = 2H-6-6-4-2-2(2-4-2); DS = 22; V = 14–15; NDV = 36–37. Inner prong of palpal claw twice as short as outer prong and located medially on the latter; scutal and dorsal idiosomal setae moderately barbed; scutum nearly trapezoidal, with small dense puncta, without transverse striae; sensilla (trichobothria) with ca. 7 branches in distal part; sensillary bases anterior to level of PL (PSB—P-PL = 6–9 µm). Standard measurements of examined specimens given in Table 7 .

Redescription (larva) (based on 7 specimens). IDIOSOMA ( Figs. 16 , 17A–E ). Eyes 2 + 2; 22 dorsal idiosomal setae, including one pair of humeral setae, moderately covered with barbs, by 6 setae in 1 st and 2 nd (D) posthumeral rows, 4 setae in 3 rd (E) row, by 2 setae in 4 th (F) and 5 th (H) rows (setae in last 3 rows can be also counted as 2-4-2); 4 sternal setae; 14–15 ventral setae; NDV = 36–37.

GNATHOSOMA ( Fig. 17F, G ). Cheliceral blade with tricuspid cap; cheliceral base with small dense puncta basally and more sparse puncta of different size in distal part; gnathobase with small dense puncta, transverse striae, and 1 pair of branched gnathocoxal (tritorostral) setae; galeal (deutorostral) seta nude; palpal claw with 2 prongs, inner prong twice as short as outer prong and located medially on the latter; palpal femur with puncta and branched seta; palpal genu with puncta and branched (5 of examined specimens) or nude (2 of examined specimens) seta; palpal tibia with three nude setae; palpal tarsus with 7 branched setae, nude subterminala (ζ) and basal tarsala (ω).

SCUTUM ( Figs. 16C , 17A ). Nearly trapezoidal, densely covered with small puncta, without transverse striae, with small anterolateral shoulders, anterior scutal margin sinuous, lateral margins concave, posterior margin broadly rounded; AM at level of AL, sensillary (trichobothrial) bases anterior to level of PL (PSB—P-PL = 6–9 µm); all scutal setae uniform with dorsal idiosomal setae; PL ≥ AM> AL; flagelliform sensilla (trichobothria), with ca. 7 branches in distal half.

LEGS ( Fig. 18 ). 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, 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 1B; trochanter 1B; basifemur 2B; telofemur 4B; genu 3B, genuala; tibia 6B, 2 tibialae (φ); tarsus 16B, tarsala (ω), microtarsala (ε) proximal to tarsala, pretarsala (ζ). Leg III: coxa 1B; trochanter 1B; basifemur 2B; telofemur 3B; genu 3B, genuala; tibia 6B, tibiala; tarsus 14B, mastitarsala.

Distribution. French Guiana, Venezuela, Surinam, and Costa Rica ( Stekolnikov et al. 2007).

Hosts . Mammalia: Cuniculus paca (L.) (= Agouti paca ) ( Rodentia : Cuniculidae ), Dasyprocta leporina (L.) ( Rodentia : Dasyproctidae ), Proechimys guyannensis (É. Geoffroy) (= P. cayennensis ), P. semispinosus (Tomes) ( Rodentia : Echimyidae ), Rhipidomys sp. ( Rodentia : Cricetidae ), Caluromys philander (L.), Marmosops fuscatus (Thomas) (= Marmosa fuscata ), Marmosa robinsoni Bangs ( Didelphimorphia : Didelphidae ), Artibeus lituratus (Olfers) , Carollia brevicauda (Schinz) ( Chiroptera : Phyllostomidae ); Aves: Formicarius analis ( Passeriformes : Formicariidae ), Henicorhina leucosticta pittieri ( Passeriformes : Troglodytidae ), Turdus leucomelas Vieillot ( Passeriformes : Turdidae ) ( Stekolnikov et al. 2007).

New host records: Gymnopithys bicolor and Momotus lessonii .

Material examined. Ten larvae ( ZIN 9261–9270) ex F. analis No LT 157, 2 larvae ( ZIN 9249, 9251) ex G. bicolor No LT 131, 2 larvae ( ZIN 9291, 9294) ex H. leucosticta No LT 182, 3 larvae ( ZIN 9226, 9227, 9235) ex M. lessonii No LT 108, COSTA RICA: Cordillera de Talamanсa, Las Tablas, 20–22 August 2010.

Remarks. The most characteristic traits of this species, in addition to fD = B/B(N)/NNN, are a large distance between caudal setae ( Fig. 17D ), the blunt posterior end of idiosoma ( Floch & Fauran 1957, fig. I, 3; compare with Fig. 16A in the present paper), and the presence of two additional ventral caudal setae laterally ( Fig. 17E ; fV = 6-2- 2-4 vs. 6-2-2- 2 in the drawings of all species described above). It is worth to notice that these setae are also present in the form described by Bassini-Silva et al. (2019) as E. tinami (fV = 6-2-2-4-2).

Figures

FIGURE 16. Eutrombicula pacae (Floch and Fauran, 1957), specimen ZIN 9235 (sensilla lost).A—general view, B—dorsal aspect of idiosoma, C—scutum, D—ventral aspect of idiosoma. Scale bars: 100 µm (A), 50 µm (B–D).

FIGURE 17. Eutrombicula pacae (Floch and Fauran, 1957).A—scutum and eyes (specimen ZIN 7219—right), B—dorsal idiosomal seta (specimen ZIN 9226), C—ventral idiosomal seta (specimen ZIN 9226), D—dorsal aspect of idiosoma (specimen ZIN 9249), E—ventral aspect of idiosoma (specimen ZIN 9249), F—dorsal aspect of gnathosoma (specimen ZIN 9226), G—ventral aspect of gnathosoma (specimen ZIN 9226).Abbreviations as in Fig. 2. Scale bars: 50 µm (A), 20 µm (B, C, F, G), 100 µm (D, E).

FIGURE 18. Eutrombicula pacae (Floch and Fauran, 1957), specimen ZIN 9226.A—leg I (trochanter–tarsus), B—leg II (trochanter– tarsus), C—leg III (trochanter–tarsus).Abbreviations as in Fig. 3.