Neocarus misiones, Vázquez & Bernardi & Klompen, 2020

Vázquez, Maria Magdalena, Bernardi, Leopoldo Ferreira de Oliveira & Klompen, Hans, 2020, The family Opilioacaridae (Acari: Parasitiformes) in Argentina, with description of two new species, Acarologia 60 (3), pp. 505-519 : 508-511

Neocarus misiones n. sp.

Zoobank: 144FCF66-D9A1-4C22-AE7E-F45E462FD7B1

Figures 1–4 , 5 A–B, 6–7, 8A

Diagnosis — Palp genu with ~8 p - type setae, palp tarsus with 6 foliate setae with 4 rounded lobes each, and 15 ch - type sensilla. Sexual dimorphism in setation of prodorsal shield absent. Sternal setae st2 and st3 with attenuate tips. Pregenital region in male with 8–9 setae, mostly thick, ribbed and blunt, but a few lightly ribbed and tapering. Pregenital region in female without setae, genital region with 12–13 thick, lightly ribbed and barbed, tapering setae. Genital region in male with 7–9 barbed, lightly ribbed, tapering setae. Ovipositor without terminal sensilla but with three very distinct rounded terminal lobes and a bilobed membranous cover.

Description — Description based on 4 females and 4 males. Immatures not available.

Gnathosoma

Chelicera ( Figure 1A ). Basal segment in adults with 1 seta (cht), fixed digit with 3, one of those (ch1 ′) large, thick. Seta cht on basal segment of male chelicera shorter than seta ch1 ″ on fixed digit. Setae ch2 ′, ch2 ″ and cht in females and males simple, with an attenuated tip, lightly serrate. Number of the ventral denticles on movable digit in both female and male one ( Figure 1A , arrow). Axial scale-like processes on movable digit in both female and male absent.

Subcapitulum ( Figure 1B ). All four pairs of paralabial setae present: pl1 relatively large, conical, With ’ s organ (pl2) membranous and discoid with a biramous core; rutellum pl (3) with one row of 5 teeth, inserted dorso-lateral; pl4 small, inserted dorsal. With 4 circumbuccal (cb) and 8–11 median and subcapitular vm (, lvm, ldm, vp, lvp) setae. Seta vm1 on the male subcapitulum present. Setae vm1 plus one more lateral setal pair with blunt tips in both sexes, all other subcapitular setae with attenuate tips. Females generally with more subcapitular setae (10–11) than males (8–9). Lateral lips in all instars with distinct canals (ogl1 and ogl2).

Palp ( Figure 2 ). Trochanter with 4 large, ribbed, tapering setae (= r - type); femur with 9–13 papilliform (= p - type) and 15 r - type setae; genu with 8 p - type and 29 r - type setae; tibia with 30 long, lightly serrate and pointed setae, 27 r - type setae, and 2 long, thin, smooth sensilla. Tibia ventrally with one small indistinct gland; similar glands not observed for other palpal segments. Tibia and tarsus partially fused. Tarsus with 6 foliate d (- type), 8 v, 15 ch, and 9 sm sensilla, plus 3 solenidia (= s - type sensilla). Foliate sensilla each with 4 lobes with rounded, not filiform, tips. Modified sm3 - type sensilla on male palp tarsus absent. Lyrifissures iα and iπ (not drawn) present. Pretarsus in shape of a pair of well-developed, smooth, sessile claws.

Idiosoma

Color. Dark blue and violet stripes on both body and legs. Body often with brownish background reflecting ingested food.

Dorsum. Prodorsal shield in adults with 142(M)–164(F) setae (N=1 for both) and two pairs of lateral eyes. One pair of prodorsal lyrifissures present ( Fig 3A , grey arrow). Setae somewhat rounded and “puffed-up” ( Figure 3 , detail). Sexual dimorphism in setal shape or setal arrangement minimal (setae in female appear slightly larger). Dorsal idiosoma between the shield and the preanal segment without setae, but with numerous lyrifissures arranged in transverse rows. Setation of preanal segment limited to 1 dorsal, and 2 ventro-lateral setae. Anal valves with 10–16 setae each, with females showing higher numbers.

Sternitogenital region ( Figure 4 ). Sternal verrucae in adults each with 3–4 large, serrate and pointed, and 1 composite St (1) seta. Setae St1 subequal in size to St5. Setae St2 and St3 in females and males barbed, tapering to a fine tip. Remaining sternal region with 4–6 pairs of stout, ribbed, setae with rounded tips. Pregenital capsules each with 1 long, tapering seta (St5) and 4–6 stout, ribbed, blunt-tipped setae. Pregenital and genital areas in female with, respectively, 0 and 12–13 sturdy, lightly ribbed and barbed, tapering setae ( Figure 5A ). Male with 8–9 setae in pregenital region, mostly thick, ribbed and blunt, but a few lightly ribbed and tapering. Genital region 7–9 barbed, lightly ribbed, tapering setae ( Figure 5 B–C). Ovipositor ( Figure 6 ) without terminal setiform sensilla, but with three very distinct roundish terminal lobes. Without well sclerotized internal structures. Terminal area in one female (the only one where this area was fully visible) covered by a bilobed membrane/tectum ( Figure 6A , arrow). Male genital valves rectangular to curved, not triangular. Male glands well developed, both pairs of similar size ( Figure 7 ).

Legs

Length of legs I–IV in females, respectively, 3937–4200, 2185–2302, 2106–2367, and 3240–3390 (N=3), for males slightly shorter, respectively 3114–4162, 2025–2315, 2184, and 3065 (N=1–3). Ratio of legs I to idiosoma in female approximately 1.8–1.9, legs IV to idiosoma about 1.5–1.7. Eupathidium ζ1 on tarsus I inserted in dorsal sensory field; simple, without enlarged tip ( Figure 8A ). Smooth setae on tibia, genu and femur I absent in the male. Solenidion ω a on legs II positioned on acrotarsus; ω a on tarsi III–IV absent. Solenidion ω d on basitarsi II–IV inserted in apical portion, partially in a cup inside the segment. Tip of setae ld of ambulacra II–IV in male smooth and attenuate. Ventral portion of acrotarsi II–IV with 3 pairs of setae; lateral portion with 2 pairs distinctly lateral, plus 1 pair of ventro-lateral and one pair of dorso-lateral setae. Setae lv of acrotarsi II–IV with one, rarely two, small barbs. Papilliform setae on dorsal portion of the basitarsi II–III present; thin, smooth setae present in male, absent in female. Coronidia present on basitarsi II–IV in all adults, absent on tibiae and genua II–IV. The condition of the specimens (poor clearing) prevented making accurate counts of the smooth setae and coronidia.

Collection information — Type depository. Holotype female, MACN-AR 41730 (5 slides), MACN. Paratypes in OSAL (MACN-AR 4031/7) and MACN (all other).

Locality data. Holotype female, MACN-AR 41730 : Argentina, Misiones, Iguazu, Puerto Libertad , 173m, 25.9189°S 54.5818°W, Oct 1954, coll. Schiapelli and De Carlo, no data on habitat. Same collection data: one female, MACN-AR 28898 /3 (4 slides), one male MACN-AR 28898 /2 (3 slides). Same locality, Oct 1953, coll. De Carlo, Schiapelli, Viana and Galiano, ex area with palm trees: two females, MACN-AR 4031/5 (2 slides), MACN-AR 4031/6 (1 slide), two males, MACN-AR 4031/7, MACN-AR 4031/8 (1 slide each).

Etymology — The specific name is derived from the primary collection locality, Misiones province, Argentina.

Comparative notes — This comparison is limited to described Neocarus species from South America, with exception of N. ojasti Lehtinen, 1980 . The description of N. ojastii does not provide sufficient detail for an adequate comparison. Comparisons with N. platensis are based on the original description by Silvestri (1905), the re-description by Van der Hammen (1969) based on Brazilian material, and comments and notes by Marcel Santos de Araújo based on examination of the type series.

Neocarus misiones differs from N. coronatus Araújo et al., 2018 by the absence of distinct sexual differentiation in the setation of the prodorsal shield, and the presence of 6, rather than 4, d setae on the palp tarsus; from N. potiguar Bernardi et al., 2012 , N. proteus Bernardi et al., 2013 , and N. platensis by the absence, vs. presence, of pregenital setae in the female ( Hammen, 1969; Araújo, pers. comm.). It differs from N. caipora Bernardi et al., 2014 and N. spelaion Bernardi and Borges-Filho, 2018 by the different shape of the genital setae in the female (sturdy and ribbed vs. thin and smooth), and the presence of 4, rather than 3 lobes on the d setae on the palp tarsus ( N. caipora only).

Figures

Figure 1 Neocarus misionesn. sp., female (MACN-AR 4031/5). A – chelicera; B – subcapitulum. Scale bar 100 µm.

Figure 2 Neocarus misionesn. sp., female (MACN-AR 28898/3), palp, axial (left) and antiaxial (right) view: A – femur; B – genu; C, tibia; D, tarsus. Scale bars A–C: 100 µm, D: 50 µm.

Figure 3 Neocarus misionesn. sp., prodorsal region: A – female (MACN-AR 4031/6) (grey arrow indicates lyrifissure); B – male (MACN-AR 4031/7). Scale bar 100 µm. Inset: detail anterior prodorsal setae.

Figure 4 Neocarus misionesn. sp., sternitogenital area: A – female (MACN-AR 4031/5); B – male (MACN-AR 4031/8). Scale bar 100 µm.

Figure 5 Neocarusspp., details pregenital and genital setae.Neocarus misionesn. sp. A – genital setae female (MACN-AR 4031/6), B – genital and C – pregenital setae male (MACN-AR 28898/2); N. entrerios n. sp. D – genital setae female (MACN-AR 28895/6), E – genital and F – pregenital setae male (MACN-AR/3). Scale bar 25 µm.

Figure 6 Neocarus misionesn. sp., female (MACN-AR 41730, holotype), ovipositor: A – composite drawing of several specimens (arrow indicates bilobed tectum), B – stacked image (MACN-AR 4031/1). Scale bar 100 µm.

Figure 7 Neocarus misionesn. sp., male (MACN-AR 28895/2), glands. Scale bar 200 µm.

Figure 8 Neocarusspp., tip tarsus I: A – N. misiones n. sp., female (MACN-AR 4031/5); B – N. entrerios n. sp., female (MACN-AR 28895/5). Scale bar 50 µm.