Ethiovertex africanus ( Evans, 1953 )

ErmilovK, Sergey G., RybalovK, Leonid B. & SharapovK, Denis V., 2024, Ontogenetic instars ofEthiovertex africanus (Evans, 1953) (Acari, Oribatida, Scutoverticidae), Acarologia 64 (2), pp. 525-541 : 527-538

Ethiovertex africanus ( Evans, 1953)

( Figures 1–11 )

Supplementary description of adult — Measurements – Body length: 570–615 (males), 600–660 (females); notogaster width: 330–360 (males), 345–390 (females).

Integument ( Figs 1b , 3c , 9a–d , 10a ) – Body dark brown. Surface of body and legs slightly densely microtuberculate (well visible in dissected specimens under high magnification, ×1000), covered by thin layer of blocky cerotegument including dense microgranulate components and dirt; cerotegumental microgranules frequently forming club-shaped and ridge-like structures; interlamellar region with two slightly oblique ridges and some mediobasal ridges; humeral region of notogaster narrowly depressed and bordered by long, oblique ridge; dorsal part of notogaster with indistinct ridges and depressions in light microscope, but well observable in SEM; medioposterior part of subcapitular mentum with some transverse and oblique ridges; lateral side of body and ventral plate with some ridges.

Prodorsum ( Figs 1b , 2a, c , 3b , 9a–d , 10a ) – Rostrum broadly rounded (but it seems truncated in dorsal aspect), forming rostral “visor″. Lamella about 2/3 length of prodorsum, view; c – subcapitulum, ventral view; d – right lip with adoral setae, ventral view; e – palp, left, paraxial view; f – left, paraxial, antiaxial view.

Scale bars 100 μm (a), 50 μm (b–d, f), 20 μm (e).

with long (about 1/2 length of lamella), broad cusp having anteromedial triangular process (but sometimes it seems rounded in dorsal aspect); translamella present, thin. Rostral (41–49) and lamellar (52–60) setae rod-like, roughened, curved; bothridial seta (41–49) erect, with short stalk and globular, barbed head; stalk and head slightly differing in length; interlamellar and exobothridial setae and their alveoli absent.

Notogaster ( Figs 1b , 2a, c , 3a , 9a–d ) – Anterior margin distinct, convex medially. Humeral process broadly rounded, slightly developed. Lenticulus not observable. Ten pairs of notogastral setae (11–15) spiniform, roughened. Opisthonotal gland opening and all lyrifissures well visible.

Gnathosoma ( Figs 2b , 3c–f ) – Subcapitulum size: 142–150 × 94–105; mentum with anterior tectum; setae (a, h 26–34; m 30–37) rod-like, roughened; a and m slightly curved, h straight;

both adoral setae (22) rod-like, roughened. Palp length 94–101; postpalpal seta (5) spiniform, smooth. Chelicera length 146–154; setae cha (37–39; chb 34–37) setiform, barbed.

Epimeral and lateral podosomal regions ( Figs 2b, c , 9c, d ) – Epimeral setal formula:

3–1–2–2; all setae (3b 17–22; others 11–15) spiniform, roughened.

Anogenital region ( Figs 2b, c , 3a , 9c, d ) – Anogenital formula: 6–1–2–3; genital, aggenital, anal, and adanal setae g (1 22–30; others 13–17) spiniform, roughened. Adanal lyrifissure distinct.

Legs ( Figs 4a–d , 9c, d , 10a ) – Median claw thick, lateral claws thin, all slightly barbed on dorsal side. Femora I and II with dorsolateral (paraxial) brachytrachea; trochanters III, IV with dorsolateral (paraxial), femora III, IV with dorsolateral (paraxial) and tibiae I–IV with distoventral saccule. Femora II–IV with ventral ridge; femora III, IV, tibiae I–IV and tarsi I–IV with dorsal ridge; genua I–IV with lateral (antiaxial) ridge. Formulas of leg setation and

); d

solenidia: I (1–4–3–4–15) [1–2–2], II (1–4–3–4–13) [1–1–2], III (2–3–1–3–13) [1–1–0], IV

(1–2–2–3–12) [0–1–0]; homology of setae and solenidia indicated in Table 1 ; solenidia 1 φof tibia I and φ on tibia II long, subflagellate; other solenidia short, rod-like; seta s of tarsus I thorn-like, roughened (not eupathidial), located between paired setae a and pv ; setae it′ and it″

absent on all tarsi.

Description of juvenile instars — Measurements – Total length of: larva 270–300, protonymph 360–420, deutonymph 435–495, tritonymph 525–545. Total width of: larva 150–165, protonymph 194–225, deutonymph 240–270, tritonymph 330–360.

Integument ( Figs 1c , 5a–d , 6a–g , 10b–d , 11a ) – Body colorless or grayish to light brown. Surface of body indistinctly porose (visible under high magnification in dissected specimens), partially covered by thin layer of dense microgranulate cerotegument; additionally, gastronotum, anogenital and epimeral regions folded.

Prodorsum ( Figs 1c , 5a–d , 6e–g , 10c, d , 11b, c ) – Relatively short, about 1/2 (in larva) or 1/3 (in nymphal instars) length of gastronotic region. Rostrum broadly rounded (illusorily seems truncated in dorsal aspect). Prodorsum with lateral ledge in larva. Dorsal side of prodorsum with one pair of dorsolateral carinae fused by transverse carina (most likely, being vestigial lamellae and translamella); basal part with semi-quadrangular ridge-like structure. Rostral seta (LA, PN 22–26; DN 26–30; TN 30–34) setiform, slightly barbed, inserted on small tubercle; lamellar, interlamellar and exobothridial setae (LA, PN 7–11; DN 7–11; TN 13–15) spiniform, roughened; bothridial seta (LA, PN 30–34, DN 30–37, TN 34–41) erect, with short stalk and globular, barbed head; stalk shorter than head.

Gastronotic region ( Figs 1c , 5a–g , 6a–g , 10c, d , 11d–g ) – Larva with 12, nymphal instars with 15 pairs of spiniform (except setiform, erect, slightly barbed h 2 in LA; some setae modified,

with cylindrical mediobasal part and needleform distal part), roughened setae. Lengths of gastronotic setae: LA: h 2 19–26, others 9–15; PN, DN 11–15; TN 15–19. Opisthonotal gland opening and all cupules (except ip not observable) poorly visible.

Gnathosoma ( Figs 5h–j ) – Subcapitulum size: LA 56–64 × 64–67, PN 75–82 × 75–82, DN

90–97 × 90–97, TN 109–116 × 109–116; anterior part of mentum with transverse ridge; length of subcapitular setae a, m: LA 15–19; PN, DN 15; TN 22; length of subcapitular seta h: LA 11–15, PN 11, DN 11–15, TN 15–19; length of adoral seta: LA 7–11; PN, DN 7; TN 11; a, m and adoral setae setiform, slightly barbed; h with cylindrical mediobasal part and needleform distal part. Palp length: LA 56–67; PN 64–71; DN 67–75; TN 79–82; palp formula in all instars: 0–2–1–3–9(+ω); solenidion distally connected with tubercle bearing eupathidium; length of postpalpal seta: LA, PN, DN, TN 7; seta spiniform, roughened. Chelicera length: LA 64–67, PN 82–86, DN 97–105, TN 120–131; length of setae cha and chb: LA 19–22; PN, DN 22–26; TN 26–30; length of seta chb: LA 15, PN 19, DN 20–22, TN 26; both setae setiform, barbed.

Epimeral and lateral podosomal regions ( Figs 6a–g ) – Setal formulas for epimeres: LA 3–1–2 (1c as typical scale covering Claparède’s organ); PN 3–1–2–1; DN, TN 3–1–2–2; length of setae: LA, PN, DN 9–13; TN 15–19; all setae spiniform, roughened (sometimes some setae modified, represented by cylindrical mediobasal part and needleform distal part).

Anogenital region ( Figs 6a–e ) – Ontogeny of genital, aggenital, anal, and adanal setal formulas, larva to tritonymph: 0–1–3–5, 0–0–1–1, 0–0–0–2, 0–0–2–2, respectively; all setae

(PN, DN 9–13, TN 15–19) spiniform, roughened; paraproctal setae absent. Adanal cupule distinct; anal cupule not observable.

Legs ( Figs 7a–d , 8a–d , 10c, d , 11h, i ) – Claw of each leg slightly barbed on dorsal side. Femora I–IV with distoventral saccule. Formulas of leg setation and solenidia: larva

I (0–2–3–4–16) [1–1–1], II (0–2–3–3–13) [1–1–1], III (0–2–2–2–13) [1–1–0]; protonymph I (0–2–3–4–16) [1–1–2], II (0–2–3–3–13) [1–1–1], III (0–2–2–2–13) [1–1–0], IV (0–0–0–0–7)

[0–0–0]; deutonymph I (0–4–3–4–16) [1–2–2], II (0–4–3–4–13) [1–1–2], III (1–3–2–3–13)

f 1 ; f – notogastral seta f 2 ; g – notogastral seta f 1 ; h – notogastral seta d and solenidion on genua and tibia of leg III; i – dorsoanterior apophysis on tibia of leg I. Magnification: 10 × 100.

[1–1–0], IV (0–2–2–2–12) [0–1–0]; tritonymph I (1–4–4–5–16) [1–2–2], II (1–4–4–5–13) [1–

1–2], III (2–3–2–4–13) [1–1–0], IV (1–2–2–4–12) [0–1–0]; homologies of setae and solenidia indicated in Table 1.

Figures

Figure 1 Ethiovertex africanus (Evans, 1953): a – photo of locality and habitat; b – microscope image of adult, dorsal view; c – microscope image of tritonymph, dorsal view. Magnification (b, c): 10 × 40.

Figure 2 Ethiovertex africanus (Evans, 1953), adult: a – dorsal view (legs omitted); b – ventral view (legs omitted); c – right lateral view (gnathosoma and legs omitted). Scale bar 100 μm.

Figure 3 Figure 3Ethiovertex africanus (Evans, 1953), adult (c–f: dissected): a – posterior view; b – anterior part of prodorsum, anterior

Figure 4 Ethiovertex africanus (Evans, 1953), dissected 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 50 μm.

Figure 5 Ethiovertex africanus (Evans, 1953), juvenile instars (e–j: from dissected specimen): a – larva, dorsal view (part of right half of body omitted); b – protonymph, dorsal view (part of right half of body omitted); c – deutonymph, dorsal view (part of right half of body omitted – tritonymph, dorsal view (part of right half of body omitted); e – larval notogastral setah1; f – larval notogastral setah2 ; g – larval epimeral seta 1a; h – larval subcapitulum, ventral view; i – larval palp, right, antiaxial view; j – larval chelicera, left, paraxial view. Scale bars 100 μm (b–d), 50 μm (a), 20 μm (h, j), 10 μm (e–g, i).

Figure 6 Ethiovertex africanus (Evans, 1953), juvenile instars: a, b, c, d – epimeral and anogenital regions (legs and part of right half of body omitted) in larva, proto-, deuto-, and tritonymph, respectively; e – larva, lateral view (gnathosoma and legs except basal parts omitted); f, g – anterior part of body of proto- and tritonymph, respectively, right lateral view (gnathosoma and legs except some trochanters omitted). Scale bars 100 μm (b–d, g), 50 μm (a, e, f), 20 μm (h, j).

Figure 7 Ethiovertex africanus (Evans, 1953), dissected legs of larva (a–c) and protonymph (d): 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 20 μm.

Figure 8 Ethiovertex africanus (Evans, 1953), dissected legs of tritonymph (d): a – leg I (trochanter omitted), right, antiaxial view; b – leg II (trochanter omitted), right, antiaxial view; c – leg III, left, antiaxial view; d – leg IV, left, antiaxial view. Scale bar 50 μm.

Figure 9 Ethiovertex africanus (Evans, 1953), adult, SEM micrographs: a – dorsal view; b – dorsolateral view; c – right lateral view; d – right ventrolateral view.

Figure 10 Ethiovertex africanus (Evans, 1953), adult (a), larva (b, c) and protonymph (d). SEM micrographs: a – anterior view; b – cerotegument in mediocentral part of prodorsum; c – larva, dorsal view; d – protonymph, dorsal view.

Figure 11 Ethiovertex africanus (Evans, 1953), dissected larva (a–f), protonymph (g, h) and deutonymph (i), microscope images: a – cerotegument on dorsolateral part of prodorsum; b – rostral seta; c – interlamellar and bothridial seta; d – notogastral setaec1 andc2 ; e – notogastral seta