Zetorchella robertbecki, Ermilov & Subias & Shtanchaeva & Friedrich, 2021

Ermilov, Sergey G., Subias, Luis S., Shtanchaeva, Umukusum Ya. & Friedrich, Stefan, 2021, New faunistical and taxonomic data on oribatid mites (Acari: Oribatida) of Ethiopia, with description of two new species of the superfamily Oripodoidea, Acarologia 61 (3), pp. 591-601 : 597-600

Zetorchella robertbecki n. sp.

Zoobank: 30E6D357-50A5-4D87-8780-82FCE151785A

( Figures 4 , 5 )

Diagnosis — Adult. Body size: 481–614 × 348–464. Genital plate striate; anal plate foveate-reticulate. Rostral and lamellar setae long, setiform, barbed; interlamellar seta long, thickened, heavily barbed; le longest. Bothridial seta long, clavate, barbed. With 10 pairs of comparatively short, phylliform, heavily barbed notogastral setae. Epimeral and anogenital setae setiform, barbed. With two pairs of adanal setae. Leg tarsus I with 19 setae l ″ (absent).

Description of adult — Measurements – Body length: 498 (holotype: male), 481–614 (27 paratypes: 14 males and 13 females); body width: 381 (holotype), 348–464 (27 paratypes). No difference between males and females in body size.

Integument ( Figs 4 a-c, 5a) – Body color brown. Body surface densely microgranulate. Subcapitular mentum, epimeres I, II, anal plate, anterior part of prodorsum, and podosomal region between bothridium and acetabula III, IV foveate-reticulate. Interlamellar region slightly and partially foveate. Notogaster, anogenital region and epimeres III, IV sparsely foveolate (poorly visible). Genital plate longitudinally striate.

Prodorsum ( Figs 4a, 4c ) – Rostrum rounded. Lamella about 1/2 length of prodorsum. Translamella lineate. Sublamella about 1/2 length of lamella. Sublamellar porose area oval

(6 × 4), located ventral to sublamella. Tutorium long, similar to lamella in length, ridge-like, distinctly not reaching rostral margin. Rostral (77–86), lamellar (98–106) and exobothridial (41–45) setae setiform, barbed; ex thinnest. Interlamellar seta (73–82) thickened, heavily barbed. Bothridial seta (69–77) clavate, barbed, with long stalk and short head. Dorsosejugal porose area not observed.

Notogaster ( Figs 4a, 4c ) – Anterior notogastral margin slightly convex medially. Humeral process small, tubercle-like. Ten pairs of notogastral setae (41–45) phylliform (dilated mediodistally), heavily barbed. Five pairs of porose areas rounded (4). Opisthonotal gland opening and all lyrifissures distinct.

Gnathosoma ( Figs 5 a-d) – Subcapitulum size: 114–123 × 98–102. Subcapitular setae (a and h: 24–28; m: 32–36) setiform, barbed. Adoral seta (12) setiform, barbed. Palp (77–82)

with setation 0–2–1–3–9(+ω). Postpalpal seta (8) spiniform, roughened. Chelicera (123–131) with two setiform, barbed setae cha (: 41–45; chb: 24–28).

Epimeral and lateral podosomal regions ( Figs 4b, 4c ) – Epimeral setal formula: 3–1–3–3. Setae (1a, 1c, 2a, 3a: 16–20; 3c, 4c: 26–41; others: 24–32) setiform, barbed. Circumpedal carina long, strong. Discidium subtriangular.

Anogenital region ( Figs 4b, 4c ) – Six pairs of genital (16–20), one pair of aggenital (16–20), two pairs of anal (16–20), and two pairs of adanal (24–32) setae setiform, barbed. Adanal lyrifissure located close and parallel to anal plate. Marginal porose area absent.

Legs ( Figs 5 e-h) – Tridactylous. Median claw distinctly thicker than lateral claws, all slightly barbed on dorsal side; each lateral claw with small tooth ventrodistally. Tibia I with small dorsodistal apophysis bearing solenidia 1 φand φ 2. Dorsal porose area on tarsi I, II, dorsoparaxial porose area on femora I–IV and on trochanters III, IV, proximoventral porose area on tarsi I–IV, and distoventral porose area on tibiae I–IV well observed; proximoventral and distoventral porose areas often divided into two parts. Formulas of leg setation and solenidia: I (1–5–3–4–19) [1–2–2], II (1–5–2–4–15) [1–1–2], III (2–3–1–3–15) [1–1–0], IV (1–2–2–3–12) [0–1–0]; homology of setae and solenidia indicated in Table 1. Famulus on tarsus I short, erect, slightly swollen distally, inserted between solenidion 2 ωand seta ft”. Seta

s on tarsus I eupathidial, located before setae a’ and a”. Solenidion ω 1 on tarsi I, ω 1 and ω 2 on tarsus II and σ on genu III bacilliform, other solenidia setiform.

Type deposition — The holotype is deposited in the collection of the ZSM ; three paratypes are deposited in the collection of the SMNH ; 24 paratypes are deposited in the collection of the TSUMZ.

Etymology — The specific name is dedicated to our friend and colleague, the coleopterologist Robert Beck (Munich, Germany) for his more than generous provision of all necessary facilities during this field trip.

Remarks – In having phylliform notogastral and thickened interlamellar setae, Zetorchella robertbecki n. sp. is morphologically most similar to Zetorchella rugosa ( Mahunka, 1992)

from Senegal (see Mahunka 1992), however, the new species differs from the latter by the presence of long bothridial seta (versus short), setiform lamellar seta (versus thickened), the same length of setae p 1, p 2 to other notogastral setae (versus distinctly shorter), striate genital plate (versus not striate), and foveate-reticulate anal plate (versus not foveate-reticulate).

From the Afrotropical species, Z. robertbecki n. sp. is morphologically similar also to Z. cotedivoirensis Ermilov, 2019 (see Ermilov and N’Dri 2019) and Z. pedestris Berlese, 1916

(see Berlese 1916a ; Balogh 1960 – as Caloppia papillata Balogh, 1958 ; Mahunka 1991) in having phylliform dorsal notogastral setae, however, the new species differs from the former by the presence of 10 pairs of notogastral setae p (3 present) including well-developed phylliform

p 2 (versus nine pairs, p 3 absent, p 2 short, setiform), thickened interlamellar seta (versus phylliform), striate genital plate (versus not striate), and foveate-reticulate anal plate (versus not foveate-reticulate), and the absence of specific cerotegumental tuberculate pattern on the notogaster (versus present) and strong sinuous ridges forming partially unclear polygonal pattern on the ventral plate (versus present); from the latter by the presence of long bothridial seta (versus short), thickened interlamellar seta (versus phylliform), striate genital plate (versus not striate), and foveate-reticulate anal plate (versus not foveate-reticulate).

Figures

Figure 4 Zetorchella robertbeckin. sp., adult: a – dorsal view (legs omitted); b – ventral view (gnathosoma and legs omitted); c – lateral view (gnathosoma and legs omitted). Scale bar 100 μm.

Figure 5 Zetorchella robertbeckin. sp., adult: a – subcapitulum, ventral view; b – lip with adoral setae, right, ventral view; c – palp, left, paraxial view; d – chelicera, left, paraxial view; e – leg I, right, antiaxial view; f – leg II, without trochanter and tarsus, right, antiaxial view; g – leg III, without tarsus, left, antiaxial view; h – leg IV, left, antiaxial view. Scale bar 20 μm (a, b; c; d), 50 μm (e-h).