Scheloribates (Scheloribates) triangulus Ermilov, 2024

Ermilov, Sergey G., Rybalov, Leonid B. & Kuzmicheva, Evgeniya A., 2024, New Scheloribates (Acari, Oribatida, Scheloribatidae) from Ethiopia, Zootaxa 5492 (2), pp. 176-190 : 183-185

Scheloribates (Scheloribates) triangulus Ermilov sp. nov.

( Figs 5 , 6 )

Material. Holotype (male) and four paratypes (one male and three females): Southeastern Ethiopia, Oromia Region, Bale Zone, Bale Mountains National Park , 6°48′40.7″N, 39°51′07.7″E, 4050 m a.s.l., Sanetti Plateau , Afroalpine community, predominance of cushion-shaped shrubs of Helichrysum citrispinum and H. splendidum , co-dominance of Festuca richardii , Pentaschistis pictigluma , Agrostis quinqueseta , and Alchemilla haumannii , litter, 16.XI.2014 (E. Kuzmicheva).

The holotype is deposited in the collection of the Senckenberg Museum of Natural History, Görlitz, Germany; four paratypes are in the collection of the Tyumen State University Museum of Zoology , Tyumen, Russia. All specimens are preserved in a solution of 70% ethanol with a drop of glycerol.

Diagnosis. Body large, length: 900–1005. Notogaster comparatively broad. Rostrum slightly protruding, rounded. Prolamella developed partially (only mediodistal part present); translamella represented by two short lines near lamellae. Rostral, lamellar and interlamellar setae long, setiform, barbed; in ˃ le ˃ ro; bothridial seta long, lanceolate, barbed. All notogastral setae represented by alveoli. Circumpedal carina long. Anal and adanal setae medium-sized, setiform, thin, roughened. Ventrobasal tubercle of leg tibiae I, II absent; femora II–IV triangular ventrodistally; tarsus I with 19 setae (l” absent; v’ present); genu II with three setae (v’ present).

Description of adult. Measurements. Body length: 945 (holotype), 900 (male paratype), 990–1005 (female paratypes); body width (level of pteromorph): 750 (holotype), 750 (male paratype), 780–825 (female paratypes); width of ventral plate: 675 (holotype), 660 (male paratype), 690–720 (female paratypes).

Integument. Body color brown to dark brown. Surface densely microfoveolate (visible only under high magnification in dissected specimens; ×1000); podosomal region and lateral part of prodorsum partially with dense microgranulate cerotegument.

Prodorsum ( Figs 5A, C ). Rostrum slightly protruding, rounded. Lamella about 1/2 length of prodorsum; mediodistal part of prolamella developed only; translamella represented by two short lines near lamellae; sublamella and lateral keel-shaped ridge distinct; sublamellar porose area (15–19 × 9–11) oval. Rostral (112–131), lamellar (221–232) and interlamellar (273–281) setae setiform, barbed; bothridial seta (123–135) with lanceolate, barbed head, directed posterolaterad; bothridial stalk slightly longer than head; exobothridial seta (41–56) setiform, thin, roughened. Dorsosejugal porose area oval, poorly visible.

Notogaster ( Figs 5A, C ). Anterior notogastral margin nearly straight or slightly convex medially. Notogaster comparatively broad. Pteromorph large, broadly rounded laterally, its anterior margin straight (perpendicular to longitudinal axis of body in dorsal aspect). Ten pairs of notogastral setae represented by alveoli. Four pairs of saccules with small opening and drop-like channel. Opisthonotal gland opening and all lyrifissures (except ia) distinct.

Gnathosoma ( Fig. 5B ). Generally, similar to S. (S.) flexibilis . Subcapitulum size: 176–184 × 127–135; subcapitular setae (a, m: 37–41; h: 71–75) setiform, roughened; m thinner than a and h; both adoral setae (19) setiform, barbed. Palp length: 112–116; postpalpal seta (9) spiniform, roughened. Chelicera length: 187–206; setae (cha: 64–67; chb: 45–49) setiform, barbed.

Epimeral and lateral podosomal regions ( Figs 5B, C ). Epimeral formula: 3–1–3–3; all setae (1a, 2a, 3a: 26–37; 1b, 3b, 3c: 56–71; others: 34–45) setiform, thin, roughened. Humeral porose areas Am and Ah not observable. Pedotectum II rounded laterally in ventral aspect. Discidium broadly rounded. Circumpedal carina long, directed to pedotectum II.

Anogenital region ( Figs 5B, C ). Genital (g 1: 41–45; g 2 – g 4: 34–37), aggenital (26–37), anal (41–49), and adanal (67–82) setae setiform, thin, roughened.Adanal lyrifissure distinct, close and parallel to anal plate. Marginal porose area band-like.

Legs ( Figs 6A–D ). Median claw thick; lateral claws thin, with small tubercle distoventrally; all claws slightly barbed on dorsal side. Ventrobasal tubercle of tibiae I, II absent. Femora II–IV triangular ventrodistally. Proximoventral porose area on tarsi I–IV, distoventral porose area on tibiae I–IV, dorsoparaxial porose area on femora I–IV and on trochanters III, IV distinct. Formulas of leg setation and solenidia: I (1–5–3–4–19) [1–2–2], II (1–5–3–4–15) [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 . Seta s on tarsus I setiform (not eupathidial), barbed, located between (a) and (pv).

Remarks. The new species is similar to S. (S.) monosetosus from Ethiopia (see above) in the presence of large body size, lanceolate bothridial seta and medium-sized anal and adanal setae, but differs from the latter by having triangular ventrodistal part of the leg femora II–IV (versus rounded), the presence (versus of absence) of seta v’ on the leg genu II, the length of the prolamella (only mediodistal part developed versus complete), and the presence of the notogastral seta p 1 as alveolus (versus needleform seta).

Etymology. The specific epithet triangulus refers to triangular ventrodistal process on the leg femur II.

Figures

FIGURE 5. Scheloribates (Scheloribates) triangulus Ermilov sp. nov., adult: A—dorsal view (legs omitted); B—ventral view (legs omitted); C—right lateral view (gnathosoma and legs omitted). Scale bar 200 μm.

FIGURE 6. Scheloribates (Scheloribates) triangulus Ermilov sp. nov., adult: A—leg I, right, antiaxial view; B—leg II, right, antiaxial view; C—leg III, left, antiaxial view; D—leg IV, left, antiaxial view. Scale bar 100 μm.