Neocarus entrerios, 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 : 512-515

Neocarus entrerios n. sp.

Zoobank: 19D08729-13CF-4DC3-8EDF-9BFED58D6B9E

Figures 5 D–F, 8B, 9–13

Diagnosis — Palp genu without p - type setae, tarsus with 6 pairs of foliate setae with four rounded lobes each and 20 ch - type sensilla. Sexual dimorphism in setation of prodorsal shield distinct. Sternal setae St2 and St3 with attenuate tips. Pregenital area in males area with 6–10 stout, ribbed setae with relatively blunt tips, in genital area with 8–10 thinner, ribbed and tapering, setae. Females lacking pregenital setae, in genital area with 6–12 ribbed and tapering setae. Ovipositor lacking terminal sensilla, but with a very distinct pair of internal papillate hooks.

Description — Based on 4 females and 3 males. Immatures unknown.

Gnathosoma

Chelicera ( Figure 9A ). Basal segment in adults with 1 seta, fixed digit with 3, one of which (ch1”) distinctly larger. Seta cht on basal segment of male chelicera shorter than seta ch1’’ on fixed digit. Setae ch2’, ch2’’ and cht in males simple, with an attenuated tip. One large, somewhat blunt, ventral denticle on movable digit in all adults. Axial scale-like processes on movable digit in both adults absent.

Subcapitulum ( Figure 9B ). 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 6–7 median and subcapitular vm (, lvm, ldm, vp, lvp) setae. Seta vm1 on the male subcapitulum present. Lateral lips with distinct canals (ogl1 and ogl2).

Palp ( Figure 10 ). Trochanter with 3–4 ribbed, tapering setae (= r - type); femur with 4–9 (6–9 in F; 3–6 in M) papilliform (= p - type) and 13 r - type setae; genu with 0 p - type and 43 r - type setae; tibia with 21 long, lightly serrate and pointed setae, 38 r - type setae, and 2 long, thin, and smooth sensilla. Tibia and genu ventrally with a small indistinct gland. Tibia and tarsus partially fused. Tarsus with 6 foliate (d - type), 10 v, 20 ch, and 10–12 sm sensilla, plus

3 solenidia (= s - type sensilla). Foliate setae each with 4 lobes and rounded, not filiform, tips. Modified sm3 - type sensilla on male palp tarsus absent. Lyrifissures iα and iπ distinct. Pretarsus in shape of a pair of well-developed sessile claws.

Idiosoma

Color: Violet-blue with the usual banding pattern. Color observed for alcohol preserved specimens only.

Dorsum. Prodorsal shield with two pairs of lateral eyes. One pair of prodorsal lyrifissures present. Setation in females and males consisting of, respectively, 186–204 and 218–242 setae. Sexual dimorphism in anterior portion of prodorsal shield (between anterior margin and lyrifissures) distinct, with a dense grouping of 56–62 setae in males ( Figure 11A ) vs. 22– 24 in females ( Figure 11B ). Setal density in anterior area of females similar to that on the remaining shield. All setae somewhat rounded in appearance and “puffed-up” ( Figure 11 , detail). Dorsal idiosoma between the prodorsal shield and the preanal segment without setae, but with numerous lyrifissures arranged in transverse rows. Setation preanal segment limited to 1 dorsal, and 2 ventro-lateral setae. Anal valves with 12–16 stout, ribbed setae (14–16 in females; 12–16 in males).

Sternitogenital region ( Figure 12 ). Sternal verrucae in adults each with 2–3 large pointed, and 1 composite (St1) setae. Setae St1 subequal in size to St5. Setae St2 and St 3 in females and males barbed, tapering to a fine tip. Remaining sternal region with 4–6 pairs of stout, ribbed setae with blunt tips. Pregenital capsules each with 1 long, tapering seta (St5) and 6–8 (female) or 5–6 (male) stout, ribbed setae. Pregenital and genital areas in female with, respectively, 0 and 6–12 smooth, tapering setae with rounded tip ( Figure 5D ), male with, respectively, 6–10 stout, ribbed, and relatively blunt-tipped setae and 8–10 ribbed and tapering setae ( Figure 5 E–F). Ovipositor without terminal setiform sensilla, but ventrally with a pair of papillate, retrorse spines connected to a papillate ridge ( Figure 13A , arrow). More dorsally two sets of sclerotized ridges, with the middle one connecting to form a W-shaped structure ( Figure 13B , arrow). Male genital valves rectangular or curved, not triangular.

100 µm.

Figures

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 9 Neocarus entreriosn. sp. A – partial chelicera, male (MACN-AR 28895/3); B – subcapitulum, female (MACN-AR 41735, holotype). Scale bar 100 µm.

Figure 10 Neocarus entreriosn. sp., palp tarsus, female (MACN-AR 41735, holotype): A – axial (left); B – antiaxial (right) view. Scale bar

Figure 11 Neocarus entreriosn. sp., prodorsal region: A – male (MACN-AR 28895/2); B – female (MACN-AR 28895/5). Inset: detail prodorsal setae. Scale bar 100 µm.

Figure 12 Neocarus entreriosn. sp., sternitogenital area: A – female (MACN-AR 41735); B – male (MACN-AR 28895/3). Scale bars 100 µm.

Figure 13 Neocarus entreriosn. sp., female, ovipositor: A – ventral view, composite drawing of several specimens (arrow indicates papillate, retrorse spine); B – stacked image (MACN-AR 28895/4) (arrow indicates the sclerotized W-shaped structure). Scale bar 100 µm.