Eutrombicula talamancensis Stekolnikov, 2022

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 : 505-509

Eutrombicula talamancensis Stekolnikov sp. nov.

( Figs. 1–3 )

Diagnosis. SIF = 7BS-N-2-3111.1000; fsp = 7.7.7; fCx = 1.1.1; fSt = 2.2; fPp = B/N/NNN; fSc: PL> AM> AL; Ip = 839–947; fD = 2H-6-6-(4–8)-2-(2–4); DS = 22–26; V = 12–17; NDV = 34–40. Inner prong of palpal claw twice as short as outer prong and located medially on the latter; scutal and dorsal idiosomal setae covered with barbs of moderate size; scutum nearly trapezoidal, with small dense puncta and poorly visible transverse striae; sensilla (trichobothria) with ca. 7 branches in distal part; sensillary bases anterior to level of PL (PSB—P-PL = 6–11 µm). Standard measurements of type series given in Table 2 .

Description (larva) (based on holotype and 15 paratypes). IDIOSOMA ( Figs. 1 , 2A–G ). Eyes 2 + 2; 22–26 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, 6 or 8 setae in 3 rd (E) row, by 2 setae in next two rows, sometimes with 1–2 additional setae, arrangement of setae in holotype 2H-6-6-4-2-2; 4 sternal setae; 12–17 ventral setae; NDV = 34–40.

GNATHOSOMA ( Fig. 2H, I ). Cheliceral blade with tricuspid cap; cheliceral base, gnathobase, palpal femur, genu, and tibia with small puncta; gnathobase with 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; seta on palpal femur branched; setae on palpal genu and tibia nude; palpal tarsus with 7 branched setae, nude subterminala (ζ) and basal tarsala (ω).

SCUTUM ( Figs. 1C , 2A ). Nearly trapezoidal, densely covered with small puncta, with transverse striae (sometimes poorly visible), with anterolateral shoulders, anterior scutal margin sinuous, lateral margins concave, posterior margin almost straight in middle part and obliquely cut at edges; AM at level of AL, sensillary (trichobothrial) bases anterior to level of PL (PSB—P-PL = 6–11 µm); all scutal setae uniform with dorsal idiosomal setae; PL> AM> AL; flagelliform sensilla (trichobothria), with ca. 7 branches in distal part.

LEGS ( Fig. 3 ). All 7-segmented, with 1 pair of claws and claw-like empodium. Coxae with indistinct striae along segments and dense small puncta. 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.

Hosts. Attila spadiceus , Catharus frantzii , Dendrocincla homochroa , Dendrocolaptes picumnus , Glyphorynchus spirurus , Gymnopithys bicolor , Henicorhina leucosticta , Leptotila verreauxi , Momotus lessonii , Thripadectes rufobrunneus .

Type material. Holotype larva ( ZIN 9254 ) ex A. spadiceus No LT 147, COSTA RICA: Cordillera de Talamanсa, Las Tablas, 21 August 2010 . Paratypes: 1 larva ( ZIN 9255 ) with same data ; 60 larvae (interval of numbers: ZIN 9202–9293 ): ex D. homochroa No LT 186 (10 larvae), G. spirurus Nos LT 001, LT040, and LT167 (30 larvae), G. bicolor Nos LT 097, LT129, LT131, LT152, and LT156 (12 larvae), H. leucosticta No LT 182 (2 larvae), and M. lessonii No LT 108 (6 larvae), Cordillera de Talamanсa, Las Tablas, 18–21 August 2010 .

Additional material. 57 larvae (interval of numbers: ZIN 9323–9572 ): ex C. frantzii No T 330 (5 larvae), D. picumnus No T284 (8 larvae), G. spirurus Nos. T 016, T145 , T217 , T250 , and T317 (41 larvae), T. rufobrunneus No T 184 (3 larvae), COSTA RICA: Tapanti National. Park, Sector Tapanti , 31 July–11 August 2009 ; 1 larva ( ZIN 9602 ) ex L. verreauxi No R 019, COSTA RICA: Rincón de la Vieja National Park , 16 August 2009 .

Localization on hosts. In ears and around vent ( D. picumnus No T 284, G. spirurus No T 250), around vent ( G. spirurus Nos T 016, T 217, T 317).

Etymology. The species epithet talamancensis refers to the Cordillera de Talamanca mountain range where the type locality is situated.

Differential diagnosis. Eutrombicula talamancensis sp. nov. is similar to Eutrombicula costaricensis Stekolnikov, Literák, Čapek and Havlíček, 2007 and differs from it by the presence of nude palpal genual and ventral palpal tibial setae (fPp = B/N/NNN vs. B/B/NNB), greater number of idiosomal setae (DS = 22–26 and NDV = 34–40 vs. 19–21 and 31–33, respectively), longer leg tarsus III (TaIIIL = 76–84 vs. 68–74), and the presence of transverse striae on the scutum. The new species is also similar to E. tinami and differs from it by fPp = B/N/NNN vs. B/B/NNB, shorter scutum (PSB = 24–31, SD = 49–61, and AP = 26–32 vs. 35, 64, and 38, respectively), shorter AM (39–52 vs. 56), and shorter AL (35–44 vs. 48). The presence or absence of transverse striae on the scutum was not indicated in descriptions of E. tinami by previous researchers ( Oudemans 1910, 1912; Fuller 1952).

Eutrombicula tinami was recently redescribed by Bassini-Silva et al. (2019) using a new material from Brazil. Their measurements somewhat deviate from those taken by Fuller (1952) from the type series. The most noticeable differences are lesser SB (21–29 vs. 45), longer scutum (ASB = 44–49 vs. 29 and SD = 74–85 vs. 64), and shorter AM (43–46 vs. 56–59). Although the recent redescription did not consider the sculpture of scutum, the transverse striae are clearly visible on the SEM photograph given in that work ( Bassini-Silva et al. 2019: fig. 5C). Eutrombicula talamancensis sp. nov. differs from the form of E. tinami described by Bassini-Silva et al. (2019) by fPp = B/N/NNN vs. B/B/NNB, greater SB (40–47 vs. 21–29), shorter scutum (ASB = 25–32, SD = 49–61, and AP = 26–32 vs. 44–49, 74–85, and 33–36, respectively), shorter AL (35–44 vs. 46–55), and shorter legs (TaIIIL = 76–84 vs. 89–97; total lengths of legs are incomparable with our data, since these authors measured legs without coxae).

Figures

FIGURE 1. Eutrombicula talamancensis sp. nov., holotype (one sensillum 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 2. Eutrombicula talamancensis sp. nov. A—scutum and eyes (paratype ZIN 9234; transverse striae invisible), B—dorsal idiosomal seta (paratype ZIN 9246), C—ventral idiosomal seta (paratype ZIN 9246), D—ventral aspect of idi- osoma (paratype ZIN 9246), E—dorsal aspect of idiosoma (paratype ZIN 9246); F—dorsal aspect of idiosoma (paratype ZIN 9273), G—dorsal aspect of idiosoma (paratype ZIN 9210), H—ventral aspect of gnathosoma (holotype), I—dorsal aspect of gnathosoma (holotype). Abbreviations: AL—anterolateral scutal seta, AM—anteromedian scutal seta, Cb—cheliceral base, Cs—cheliceral blade, cxI—leg coxa I, cxII—leg coxa II, cxIII—leg coxa III, Ga—galeal (deutorostral) seta, gns—gnathocoxal (tritorostral) seta, H—humeral seta, ic—infracapitulum (gnathobase, gnathocoxa), PC—palpal claw (odontus), PF—palpal femur, PG—palpal genu, PL—posterolateral scutal seta, PTa—palpal tarsus, PTi—palpal tibia, S—sensillum (trichobothrium), S0—palpal tarsala (ω), sta—anterior sternal setae, stp—posterior sternal setae, V—ventral idiosomal setae, u—uropore (anus). Scale bars: 50 µm (A), 20 µm (B, C, H, I), 100 µm (D–G).

FIGURE 3. Eutrombicula talamancensis sp. nov., paratype ZIN 9246. A—leg I (trochanter–tarsus), B—leg II (trochanter–tar- sus), C—leg III (trochanter–tarsus).Abbreviations: f1—microtarsala I (ε), f2—microtarsala II (ε), ga—genuala I (σ), gm—genuala II (σ), gp—genuala III (σ), µga—microgenuala I (κ), µta—microtibiala I (κ), Mt—mastitarsala, pST—parasubterminala (z), PT’—pretarsala I (ζ), PT”—pretarsala II (ζ), S1—leg tarsala I (ω), S2—leg tarsala II (ω), ST—subterminala (ζ), ta—tibiala I (φ), tm—tibiala II (φ), tp—tibiala III (φ).