Hyracarus maximus Stekolnikov, 2025

Hyracarus maximus Stekolnikov , sp. nov.

( Figs. 1A–C View FIGURE 1 , 2–4 View FIGURE 2 View FIGURE 3 View FIGURE 4 )

Diagnosis. SIF = 7B-B-3-2111.2110; fPp = B/B/BBB; fD = [(5–7)-8(9)]-(8–10)-(8–10)-(8–12)+(15–30), DS = 54–73, V = 52–67, Hv = 3–6, NDV = 118–140; Ip = 1132–1226; scutum pentagonal, with angulate posterior margin; nasus expanded in medial part, with rounded end; sensillary bases at level of PLs (PSB–P-PL from –5 to 4, mean 0); PL> AL = AM; sensilla with very small, poorly visible cilia; cheliceral blade with dorsal tooth and row of 11–12 ventral denticles; parasubterminala ( z) branched. Unspecialized setae (leg I, II, III): femur 6, 6, 5; tibia 9, 6, 6; tarsus 32, 17, 17. Measurements are given in Table 1.

Description of larva. IDIOSOMA ( Figs. 1A, B View FIGURE 1 , 2 View FIGURE 2 ). Eyes 2 + 2, on ocular plate; 54–73 barbed dorsal idiosomal setae; distribution by anterior rows—13–15 C, 8–10 D, 8–10 E, 8–12 F, 1 st row double, two marginal setae of 2 nd row shifted anteriad, marginal setae of 1 st and 2 nd rows (humeral setae) longest; two sternal setae between coxae III; 52–67 ventral setae; 3–6 humeroventral setae between coxae II and III laterally; NDV = 118–140; stigmata and tracheae absent.

GNATHOSOMA ( Fig. 3 View FIGURE 3 ). Cheliceral blade with one dorsal tooth and ventrolateral row of 11–12 denticles; cheliceral base with small dense puncta in proximal part; gnathobase (infracapitulum) with small dense puncta, bears one pair of branched tritorostral setae; galeal (deutorostral) seta heavily ciliated; palpal claw (odontus) with three prongs; palpal femur with small puncta; palpal femoral seta branched; palpal genual seta with few branches; palpal tibia with heavily ciliated distally dorsal seta, lateral seta bearing few branches, and branched ventral seta; palpal tarsus with seven unspecialized setae (six branched ventral and one dorsal bearing very small, poorly visible cilia) and tarsala ( ω).

SCUTUM ( Figs. 1A View FIGURE 1 , 2C, D View FIGURE 2 ). With small dense puncta, pentagonal, with angulate posterior margin; nasus expanded in medial part, with rounded end; AM situated at level of ALs, sensillary (trichobothrial) bases at level of PLs (PSB–P-PL from –5 to 4, mean 0); PL> AL = AM; all scutal setae barbed similarly to dorsal idiosomal setae; sensilla (trichobothria) flagelliform, look nude, but very small, poorly visible cilia can be observed at highest magnification.

LEGS ( Fig. 4 View FIGURE 4 ). All six-segmented (with undivided femur), with one pair of claws and claw-like empodium, onychotriches absent. Sensory setae: Leg I: 2 genualae ( σ), microgenuala ( κ), 2 tibialae ( φ) in tandem, distal rod-like, striated, proximal setiform, microtibiala ( κ) near distal tibiala, tarsala ( ω), famulus ( ε) distal to tarsala, subterminala ( ζ), branched parasubterminala ( z), pretarsala ( ζ). Leg II: genuala ( σ), microgenuala ( κ) distal to genuala, 2 tibialae ( φ) in tandem, tarsala ( ω), famulus ( ε) behind tarsala, pretarsala ( ζ). Leg III: genuala ( σ), tibiala ( φ). Unspecialized setae (leg I, II, III): coxa 2, 1, 1; trochanter 1, 1, 1; femur 6, 6, 5; genu 4, 4, 4; tibia 9, 6, 6; tarsus 32, 17, 17. Ventral setae feathered, dorsal setae branched, bearing few cilia or nude. Numbers of nude setae: Leg I: tarsus 1, tibia 1 (bearing few cilia basally); Leg III: tarsus 2, tibia 1 (bearing few cilia basally), genu 1 (bearing few cilia basally).

Type material. Holotype: larva ( ZIN 18397 View Materials ), ex Micaelamys namaquensis ( No. ObMn 12), South Africa, Western Cape, Ouberg Private Nature Reserve, near Montagu, Succulent Karoo , 6 November 2023, coll. Alyssa Little. Paratypes: 20 larvae ( ZIN 18372 View Materials , 18375 View Materials , 18379–18381 View Materials , 18387–18393 View Materials , 18400 View Materials , 18401 View Materials , 18403 View Materials , 18413–18417 View Materials ), ex M. namaquensis (Nos ObMn02, 8, 12, 13, 15, 19), same locality, date, and collector ; five larvae ( ZIN 18483– 18485 View Materials , 18487 View Materials , and 18489) ex Rhabdomys pumilio (Nos. ObRp4 and ObRp6), same locality, 7 November 2023, coll. Lola Singo.

Etymology. The specific epithet refers to the size of the new species, maximal among the known species of Hyracarus .

Differential diagnosis. The new species is similar to Hyracarus mutabilis (Vercammen-Grandjean and Brennan, 1957) and differs from it in much longer legs (Ip = 1132–1226 vs. 715) and higher number of teeth on the cheliceral blade (11–12 vs. 7). In the drawing from the original description of H. mutabilis , the cilia on sensilla looks much longer than in H. maximus sp. nov., but direct comparison is required to confirm that this is a real difference.