Discoppia (Cylindroppia) cylindrica ( Pérez-Íñigo, 1965 )

ErmilovK, Sergey G. & MakarovaK, Olga L., 2023, Contribution to the knowledge of the oribatid mite genus Discoppia (Acari, Oribatida, Oppiidae), Acarologia 63 (3), pp. 757-769 : 760-765

publication ID	https://doi.org/ 10.24349/131f-vr0l
publication LSID	lsid:zoobank.org:pub:6B244B1D-D506-40AB-A69B-AF81458861A7
persistent identifier	https://treatment.plazi.org/id/0C367A58-FFB9-3263-6FA2-F94CFB0AF9EF
treatment provided by	Felipe
scientific name	Discoppia (Cylindroppia) cylindrica ( Pérez-Íñigo, 1965 )
status

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Discoppia (Cylindroppia) cylindrica ( Pérez-Íñigo, 1965) View in CoL

( Figures 2–4 View Figure 2 View Figure 3 View Figure 4 )

Material — Point 1: 127 specimens (all females): Russia, northeastern Caucasus, Dagestan Republic, 20 km N from Makhachkala City, vicinity of Shushiya village, sandy sea beach, slope of small dune, under Convolvulus persicus L. (layer 25–30 cm); 43.164938°N, 47.483112°E ;

04.XI.2022 (leg. O.L. Makarova and K. V. Makarov) ( Fig. 1b View Figure 1 ). Point 2: 104 specimens

(all females): the same data, but about 10–15 meters distant from Point 1; 43.164902°N, 47.483042°E ( Fig. 1c View Figure 1 ). All specimens (in 70% solution of ethanol with a drop of glycerol)

are deposited in the collection of the Tyumen State University Museum of Zoology, Tyumen, Russia.

Description — Measurements – Body length: 176–199 (n=100); body width: 67–90 (n=100).

Integument ( Fig. 3a View Figure 3 ) – Body color light yellowish to light brownish. Body surface with dense cuticular microgranules (visible in dissected specimens under high magnification) which well visible between bothridium and acetabula II and III. Dorsal side sometimes covered by sparse cerotegumental microgranules.

Prodorsum ( Figs 2a View Figure 2 , 3a View Figure 3 ) – Rostrum rounded. Rostral (15), lamellar (9–11) and interlamellar (9–11) setae branched; exobothridial seta (26–30) setiform, barbed, often pressed to prodorsal surface and therefore poorly observed in dorsal aspect; bothridial seta (19–22) with unilaterally dilated, nearly disk-like head bearing about 10–12 long ciliae ( Fig. 3c View Figure 3 ). One pair of muscle sigilla well visible, located close and anteriorly to interlamellar setae. Slight transverse ridge located between insertions of interlamellar setae.

Notogaster ( Figs 2a View Figure 2 , 3a, 3b View Figure 3 ) – All notogastral setae (13–15) branched; number of ciliae variable, from one to four ( Fig. 3d View Figure 3 ). Lyrifissures ia, im, ip, ih, and ips comparatively long, well visible.

Gnathosoma ( Figs 3e– 3g View Figure 3 ) – Subcapitulum size: 45–49 × 35–37; all subcapitular setae (9) setiform, slightly roughened; both adoral setae (2) setiform, smooth. Palp length: 24–26; setation: 0–2–1–3–8(+ω); tarsal seta l″ absent; solenidion long (2/3 of tarsus length); postpalpal seta (2) spiniform. Chelicera length: 45–49; setae (cha: 17–19; chb: 9–11) setiform, barbed.

Epimeral region ( Figs 2b View Figure 2 , 3a View Figure 3 ) – Epimeral border IV straight. Epimeral setae 1 (b, 3b, 3c, 4c:

9; others: 7) setiform, slightly roughened.

Anogenital region ( Figs 2b View Figure 2 , 3a, 3b, 3h View Figure 3 ) – Genital (7), aggenital (9–11), anal (9), and adanal (11–13) setae setiform, slightly roughened. Adanal lyrifissure short, distinct. Ovipositor ( Fig. 3h View Figure 3 ) elongated (39–45 × 11–13), blades (13–15) shorter than length of distal section (beyond middle fold; 26–30); setae of all blades (ψ 1, τ 1: 13; ψ 2, τ a, τ c: 11) rod-like, smooth; first blade with four setae, second and third blades with three setae only b absent (τ); coronal setae absent.

Legs ( Figs 4a–4d View Figure 4 ) – Claw of each leg with slight barb on dorsal side. Porose area on all segments not observed. Formulas of leg setation and solenidia: I (1–5–2–4–20) [1–2–2], II (1–5–2–4–16) [1–1–2], III (2–3–1–3–11) [1–1–0], IV (1–2–2–3–10) [0–1–0]; homology of setae and solenidia indicated in Table 1. Setae p′ and p″ setiform on tarsus I versus very short, spiniform on tarsi II–IV; famulus short, rod-like, located laterally to solenidion ω 1 ; seta s eupathidial on tarsus I; setae a′, a″, it′, and it″ absent on tarsus III, a′ and a″ absent on tarsus IV; many setae on segments branched; solenidia 1 ωand ω 2 on tarsi I and II, φ 2 on tibia I, φ on tibiae

II and III, and σ on genua II and III short or medium-sized, slightly or distinctly bacilliform; solenidia φ 1 on tibia I, σ on genu I and φ on tibia IV long, subflagellate.

Remarks — Based on our supplementary description and on the available data (e.g., Pérez-Íñigo 1971; Subías and Rodríguez 1986) about adult D. (C.) cylindrica , we propose the following diagnostic morphological traits for this species: body length: 176–225; rostrum rounded; rostral, lamellar, interlamellar, and notogastral setae branched; exobothridial seta setiform, barbed; bothridial seta with unilaterally dilated, nearly disk-like head; epimeral border IV straight; epimeral and anogenital setae setiform, slightly roughened; leg a′ setae, a″,

it′, and it″ absent on tarsus III, a′ and a″ absent on tarsus IV; many leg setae branched.

Taxonomical proposals

1. Oppia bifidus was described by Bayoumi and Al-Khalifa (1985). The distinctive traits of the species are morphologically variable (branches of rostral and notogastral setae; barbulation of bothridial seta) or were not correct (presence of costulae), therefore, Subías (2004) rightly synonymized it with D. (C.) cylindrica cylindrica . However, later, Subías (2022) changed his opinion and synonymized O. bifidus with D. (C.) casuarina . Discoppia (C.) cylindrica and D. (C.) casuarina are morphologically very similar differing only by the morphology of head of the bothridial seta (unilaterally dilated, nearly disk-like versus elongate fusiform). Oppia bifidus has unilaterally dilated, nearly disk-like head of bothridial seta ( Bayoumi and Al-Khalifa 1985), therefore, we maintain the initial synonymy ( O. bifidus with D. (C.) cylindrica ) of Subías in 2004.

2. Subías (2004, 2022) considered the species Oppia agricola Fujikawa, 1982 as a junior synonym of D. (C.) cylindrica . However, all morphological traits of O. agricola clearly correspond to the generic diagnosis of Microppia Balogh, 1983 ( Balogh 1983 ; Subías and Shtanchaeva 2023); for example, this species has one pair of small sclerotized tubercles running from dorsosejugal scissure to basal part of prodorsum (versus absent in Discoppia ) and differing localization of notogastral seta lm to la (medially versus mostly posteriorly in Discoppia ). Therefore, we: 1) do not support the synonymy proposed by Subías (2004), 2) propose a transfer of O. agricola in Microppia : Microppia agricola ( Fujikawa, 1982) n. comb.

3. Subías (2004, 2022) included the species Oppia tenuis Hammer, 1958 in D. (Cylindroppia). However, some important morphological traits of this species clearly do not correspond to the generic diagnosis of Discoppia ; for example, O. tenius has differing localization of notogastral seta lm to la (medially versus mostly posteriorly in Discoppia ) and seta c (distanced from humeral region versus in humeral region). Therefore, we do not support the placement of O. tenuis in Discoppia . The problem is that O. tenuis was described briefly by Hammer (1958), and its ventral side, containing important diagnostic characters (e.g., epimeral formula; number of genital setae; localization of adanal setae and adanal lyrifissure), is completely unknown, therefore, an objectively correct placement of O. tenuis in any known oppiid genus seems almost impossible at the moment.

4. Discoppia (Cylindroppia) cylindrica rostroincisa was described by Subías and Rodríguez (1986). This subspecies differs from D. (C.) cylindrica cylindrica only by one morphological trait (rostrum incised medially versus rounded). The morphology of the rostrum is not variable in specimens of the same oppiid species and is widely used in taxonomy of the family at the species and generic levels. Therefore, in our opinion, this difference is sufficient to support the insularity of Discoppia rostroincisa on species level, and we propose a species status (instead of the existing subspecies status) for this species: Discoppia (Cylindroppia) rostroincisa Subías and Rodríguez, 1986 n. stat.