Epidamaeus globifer ( Ewing, 1913 )

Norton, Roy A. & Ermilov, Sergey G., 2021, Redescriptions of North American Epidamaeus (Acari, Oribatida, Damaeidae) species proposed by N. Banks, H. E. Ewing, A. P. Jacot, and J. W. Wilson, Zootaxa 5021 (1), pp. 1-65 : 29-37

Epidamaeus globifer ( Ewing, 1913)

( Figs 12–17 )

Damaeus globifer Ewing, 1913, p. 120

Belba globifer ( Ewing, 1913) ; Wilson (1936, p. 260)

Epidamaeus globifer ( Ewing, 1913) ; Marshall et al. (1987, p. 140)

Damaeus (Epidamaeus) globifer ( Ewing, 1913) ; Subías (2004, p. 79)

Diagnosis

Epidamaeus species with total length of adult 752–879. Cerotegument comprised of very thick, loose layer of filamentous excrescences; exuvial scalps usually present on notogaster. Propodolateral apophysis and postbothridial enantiophysis absent. Bothridial seta straight, barbed, gradually tapered to acicular tip; seta in relatively large, barbed. Notogaster with spina adnata triangular, barely reaching edge of notogaster; setae of c -, l - and h -series acicular, smooth, slightly arched, radially directed. Parastigmatic enantiophysis dimorphic: Sa horn-like, Sp short, Enantiophyses L, E2, V and M absent; discidium narrow, fang-shaped. Seta ad 3 close to anal plate. Leg IV approximately equal to body length; femur IV slightly longer (1.1–1.3) than trochanter IV. Juveniles with famulus minute, non-emergent from sunken pit; seta d of genua I–III minute in larva, normally formed in nymphs.

Adult

Dimensions. Total length and maximum width (n = 8 females, 4 males) 752–879 × 461–564; males usually smaller (752–776) than females (763–879).

Integument. Color of preserved specimens medium brown. Cerotegument excrescences filamentous with dustlike surface particles, forming thick layer on legs and body ( Fig. 13A, C–E ), often with adherent fungal spores (sometimes abundant) but usually without noticeable organic debris; cerotegument absent or partially present on setae. Procuticle almost entirely smooth; proximal region of trochanters III, IV microtuberculate. With full stack of juvenile exuvial scalps, those of females often with attached eggs or eggshells (up to 12 observed; Fig. 13B ).

Prodorsum ( Fig. 12A, B ). Body wall anterior to acetabulum I nearly transverse in dorsal view; that of acetabulum II oblique, broadly rounded. Propodolateral apophysis and enantiophyses B, D, L absent. With well-defined, steplike transverse contour anterior to setal pair le, and another anterior to each bothridium. Bothridium with projecting part funnel-shaped, with weak vertical banding. Bothridial seta (up to 184) nearly straight, directed dorsolaterally; acicular, gradually tapered to point but tip usually broken; with minute barbs in distal 2/3. Setae ro (86–94) and le (102–114) finely attenuate, weakly barbed in proximal half, curved anteromediad, le slightly thicker than ro; in relatively large (135–151), straight, acicular, barbed, usually directed posterolaterad; ex (77–90) attenuate, weakly barbed; vestige exv present, immediately posterior to ex, separated by about its diameter.

Notogaster ( Fig. 12A–C ). Nearly circular in outline, about 1.1 times longer than broad; uniformly curved, hemispherical with maximum height in middle ( Fig. 13A ). Spina adnata of medium length (41–45), barely extending to notogastral margin, directed slightly anterolaterad; triangular in dorsal view, sometimes distally forked ( Fig. 13A , insert) or with small lateral tooth; pair widely spaced, mutual distance greater than that of setal pair in. Setae of c -, l - and h -series directed radially, inserted in curved row such that mutual distance of lyrifissure im about 1.4 times that of lm in dorsal view; c 1, c 2 (94–102), la, lm, lp, h 1, h 2, h 3 (110–135) dark, acicular, slightly bowed, usually smooth. Setae of p -row finely attenuate, barbed proximally; p 1 (69–73) slightly thicker than p 2 (69–73), p 3 (57–65) thinnest. Setae of p row dimorphic: p 1 (77–90) similar to dorsal setae; p 2 and p 3 (69–86) attenuate, weakly barbed, without noticeable pigment, curved laterad. Lyrifissures ia, im, ip, ih, ips, opisthonotal gland opening (gla), and circumgastric sigillar band all distinct in transmitted light.

Coxisternum and lateral podosoma ( Fig. 12B, D ). Tectum of podocephalic fossa normally developed, without lateral tooth-like projection. Coxisternal pit (cp) of epimere I, shallow, with vaguely defined margins. Enantiophyses E2, V and M absent. Parastigmatic enantiophysis dimorphic: tubercle Sa horn-like, slightly curved posterolaterad, Sp short, conical, directed perpendicularly to Sa. Epimeral setae attenuate, weakly barbed, relatively long (1b, 3b, 3c, 77–86; others 61–89), none inserted on noticeable tubercle; 3c about equidistant from tubercle Sp and acetabulum III. Discidium narrow, elongated, fang-shaped, slightly curved posteriad.

Anogenital region ( Fig. 12D ). Genital (61–69), aggenital (61–69), anal (69–82), and adanal (69–82) setae attenuate, weakly barbed. Seta ad 3 inserted close to anal aperture, nearly aligned between ad 2 and ag. Lyrifissure iad diagonally oriented, immediately anterior to ad 2; ian anterolateral to seta an 2, minute, length about equal to setal alveolus diameter. Medial edge of anal plate with usual narrow longitudinal band, sharply demarcated by carina.

Gnathosoma ( Fig. 14 ). Subcapitulum longer than wide (147–159 × 106–118). Subcapitular setae (a, 28–32; m, h, 53–61) attenuate, barbed. Adoral setae (16) acuminate, thin, smooth. Palp (131–139) with typical setation: 0–2–1–3–9(+ω). Solenidion baculiform, appressed to surface. Postpalpal seta (8) spiniform, smooth. Chelicera (147–159) typical of family; attenuate seta cha (41–49) barbed throughout, chb (28–32) barbed unilaterally in distal half.

Legs ( Figs 13D , 15A –D ). Relative lengths (I to IV) 1.0: 0.8: 0.9: 1.1; leg IV approximately equal to body length. Femur IV slightly longer (1.1–1.3) than trochanter IV; approximate length of all leg segments shown in Table 1. Proximal stalk of femur IV shorter (~ 0.7) than distal bulb. Claws smooth; without proximoventral tooth. Formulas of leg setation and solenidia: I (1–7–4–4–20) [1–2–2], II (1–6–4–4–17) [1–1–2], III (2–4–3–3–17) [1–1– 0], IV (1–4–3–3–13) [0–1–0]. Notably: proximal accessory pair (v) present on tarsi I–III but only vʹ present on IV (v 2 ʹ and v 2 ʺ absent); v 2 ʺ present on femur I, absent from II; seta vʺ absent from femur III. Setae d and l of femora not unusually enlarged; d of genua barbed, to attenuate, ~1.5 times longer than respective coupled solenidia. Solenidion φ 1 on tibia I flagellate, φ on tibia IV slightly shorter (subflagellate), others tapered but blunt (‘ceratiform’), erect or curved distally. Famulus of tarsus I acicular, erect. Shapes and relative sizes of other setae shown in Fig. 15 .

Juveniles ( Figs 16 , 17 )

Dimensions. Total length of LA 282, 298 (n = 2), PN 365–398 (n = 4), DN 498–531 (n = 3), TN 630–697 (n = 3). Maximum width of LA 166, 174, PN 232–240, DN 282–315, TN 381–431.

Integument. Color of body yellowish to light brown. Cerotegument comprising thick layer of tuberculate excrescences. Body setae usually without cerotegument.

enlargements of: seta h 1, lower left; exobothridial region, upper right; forked spina adnata, lower right); B—enlargement from A, showing egg shells attached to exuvial scalps; C (SEM)—cerotegument from notogaster; D—legs I–IV from dissected specimen; E—leg I, distal region of tibia and proximal half of tarsus. Scale bars 2 μm (C), 20 μm (E), 50 μm (B, D), 100 μm

(A).

Prodorsum. About 2/3 length of gastronotum in larva, 1/ 2 in nymphs. Rostrum rounded. Setae ro (LA, 36–41; PN, 49–57; DN, 61–65; TN, 73–82), le (LA, 45–53; PN, 61–69; DN, 73–82; TN, 90–102) and ex (LA, 32–36; PN, 45–49; DN, 53–61; TN, 65–73) attenuate, weakly barbed, inserted on small tubercles; seta in similar in larva (36–41), but in nymphs short (PN, 20–24; DN, 24–28; TN, 32–41), bacilliform, truncate distally, smooth. Bothridial setae long, barbed, attenuate to subflagellate (all with broken tip, unmeasurable).

Gastronotic region. Posteriorly rather truncate in larva ( Fig. 16A ); more rounded in nymphs ( Fig. 17D ), with small protruding pygidial sclerite. Gastronotic setation normal; setal form heterogeneous, larger setae darkly pigmented, all barbed and probably attenuate to subflagellate (most broken and not measurable). In larva, based on setal remnants and size of tubercles, setae with following size relationships: dp, lp ˃ c 1, c 2, da, h 1 ˃ dm ˃ c 3, la, lm, h 2 ˃ h 3. In PN c 1, c 2, la, lm, lp, h 1 ˃ h 3 ˃ h 2 ˃ p 1 ˃ c 3, p 2, p 3; in DN and TN c 1, c 2, la, lm, lp, h 1, h 3 ˃ h 2, p 1 ˃ c 3, p 2 ˃ p 3. All cupules and opisthonotal gland openings distinct and with normal ontogeny. Attachment cornicle k of nymphs elongated, with slight S-bend, positioned between setal pair h 3. ( Fig. 17B, D ).

Venter ( Figs 16A , 17A, C, E ). Setal ontogeny and cupular development normal; seta h 3 small, but well-formed in larva. Except for larval 1c (formed as typical scale covering Claparède’s organ) epimeral setae attenuate, weakly barbed, sized as follows: LA, 12–16; PN, 1b, 3b, 20–24, others 16; DN, 1b, 24–28, others 20; TN 1b, 45–53, others 24–32. Genital (PN, 16; DN, 20; TN, 24–32), aggenital (DN, 20; TN, 24–32), adanal (DN, 24–28; TN, 28–36), and anal (TN, 24–32) setae attenuate, weakly barbed.

Gnathosoma ( Fig. 16D, E ). Subcapitulum longer than wide (LA, 61–65 × 69–73; PN, 73–82 × 82; DN, 90 × 90; TN, 114 × 114). Subcapitular setae (LA: a, 12–16; h, m, 16–20; PN: a, 16; h, m, 20; DN: a, 20–28; h, m, 28–32; TN: a, 32; h, m, 41) attenuate, weakly barbed. Adoral setae (LA, 6; PN, 8; DN, 10; TN 14–16) acuminate, thin, smooth. Palps (LA, 61; PN, 69; DN, 82–90; TN, 110) with typical setation, 0–1–1–3–9(+ω) in larvae and 0–2–1–3–9(+ω) in nymphs. Solenidion baculiform, appressed to surface. Postpalpal setae (LA and PN, 4; DN, 6; TN, 8) spiniform, smooth. Chelicerae (LA, 61–65; PN, 73; DN, 86; TN, 114) with cha (LA, 16–20; PN, 20; DN, 26–28; TN, 32) attenuate, barbed, chb (LA, 12–16; PN, 16; DN, 20; TN, 24) unilaterally ciliate in distal half.

φ 1 incomplete, shown in Fig. 18E ); B—femur, genu and tibia of right leg II, abaxial view; C—left leg III, without tarsus, abaxial view; D—left leg IV, abaxial view. Scale bar 50 μm.

Legs ( Fig. 16F–H ). Claws as in adult. Complement of setae and solenidia: LA, I (0–2–3–4–16) [1–1–1], II (0–2–3–4–13) [1–1–1], III (0–2–2–3–13) [1–1–0]; PN, I (0–2–3–4–16) [1–1–2], II (0–2–3–4–13) [1–1–1], III (1– 2–2–3–13) [1–1–0], IV (0–0–0–0–7) [0–0–0]; DN, I (1–4–4–5–16) [1–2–2], II (1–4–4–4–13) [1–1–2], III (2–3–3– 4–13) [1–1–0], IV (0–2–2–3–12) [0–1–0]; TN, I (1–4–4–5–18) [1–2–2], II (1–4–4–5–15) [1–1–2], III (2–3–3–4–15) [1–1–0], IV (1–3–3–4–12) [0–1–0]. Ontogeny of setae and solenidia as in E. michaeli (Table 4) except as follows: seta v 1 ʺ on femur I delayed to adult; seta vʹ of genu IV tritonymphal; seta lʺ of tibia II larval; seta vʹ of tarsus IV does not appear. Setal pair (p) appears eupathidial on tarsus I in all instars, seta s normal in all juvenile instars (becoming eupathidial in adult). Famulus of tarsus I minute, sunken in sclerotized cup in all juvenile instars; with short, compact internal root. Seta d minute on all genua of larva (see enlargement in Fig. 16F, G ); in nymphs d always distinctly longer than coupled solenidion σ.

Figures

FIGURE 12. Epidamaeus globifer (Ewing, 1913), adult: A—dorsal view (legs not shown); B—anterior half of body, right lateral view (gnathosoma and legs not shown); C—posterior region of body, right lateral view); D—ventral view (legs not shown). Scale bar 100 μm.

FIGURE 13. Epidamaeus globifer (Ewing, 1913), light and SEM photographs of adult: A—habitus, lateral view (inserts =

FIGURE 14. Epidamaeus globifer (Ewing, 1913), adult: A—subcapitulum, ventral view (palps not shown); B—right palp, abaxial view; C—left chelicera, adaxial view. Scale bar 50 μm.

FIGURE 15. Epidamaeus globifer (Ewing, 1913), adult: A—right leg I, without trochanter, abaxial view (flagellate solenidion

FIGURE 16. Epidamaeus globifer (Ewing, 1913), larva: A—dorsal view (legs not shown); B—lateral view (gnathosoma and legs except trochanters I–III not shown); C—ventral view (anterior third and legs not shown); D—subcapitulum, with left palp; E—right chelicera, abaxial view; F—right leg I, abaxial view; G—right leg II, abaxial view (* indicates anomalous appearance of tibial seta lʹ, see R15); H—left leg III, abaxial view. Scale bars 20 μm (D, E), 50 μm (A–C, F–H). Numerous setae broken in A–C.

FIGURE 17. Epidamaeus globifer (Ewing, 1913), nymphs: A—protonymph, ventral view (anterior third and legs not shown); B—protonymphal exuvial scalp; C—deutonymph, ventral view (anterior third and legs not shown); D—tritonymph, dorsal view (legs not shown; exuvial scalps removed); E—same, ventral view (anterior third and legs not shown). Scale bars 50 μm (A, B), 100 μm (C–E). Numerous setae broken.

FIGURE 18. Epidamaeus florida (Wilson, 1936), adult:A—dorsal view (legs not shown except trochanters I); B—anterior half of body, right lateral view (gnathosoma and legs not shown) C—posterior region of body, right lateral view; D— ventral view (legs represented only by trochanters). Scale bar 50 μm.