Eremulus flagellifer Berlese, 1908

Ermilov, Sergey G. & Hugo-Coetzee, Elizabeth A., 2012, Oribatid mites of the genus Eremulus Berlese, 1908 (Acari: Oribatida: Eremulidae) from South Africa, African Invertebrates 53 (2), pp. 559-559 : 566-568

Eremulus flagellifer Berlese, 1908

Fig. 5

Diagnosis: This species is distinguished from others by the following combination of character states: body size 262–282×135–149; rostrum weakly protruding anteriorly; transcostula absent; prodorsal setae smooth; interlamellar setae shorter than rostral and lamellar setae; sensilli flagelliform, ciliate; 11 pairs of notogastral setae, medium size, setiform, with slightly curved tips, smooth; setae lm inserted slightly anterior to level of insertions of h 3; aggenital setae branched; adanal setae ad 1 little longer than ad 2 and ad 3; epimeral setae 1c long, setiform.

Description:

Measurements. Body length 262–282 (mean 272); body width 135–149 (mean 139).

Integument ( Fig. 5A ). Body yellow-grey-brownish. Body and legs covered by secretion granules (diameter up to 1 µm). Posterior part of prodorsum and band on notogaster with few foveolae. Foveolate band over genital plates present. A small concave region present between rows of notogastral setae c and la.

Prodorsum ( Fig. 5A, C ). Rostrum weakly protruding anteriorly. Costulae long, narrow, almost straight. Transcostula absent, but rudimentary sites present. Rostral (28–32), lamellar (28–32), interlamellar (18–22) and exobothridial (8) smooth, setiform setae, inserted on tubercles. Rostral setae inserted in dorso-lateral position on prodorsum. Sensilli (65–73) flagelliform, covered by short cilia. Bothridial margins with teeth (visible under high magnification).

Notogaster ( Fig. 5A, D ). Anterior border straight. One pair of inconspicuous humeral condyles and cristae present. Eleven pairs of notogastral setae (p 3 inserted in margino-ventral position) medium size, similar in length (24–32; only p 3 shorter, 16–20), setiform, with slightly curved tips, smooth. Setae lm inserted somewhat anterior to level of insertions of h 3. Opisthonotal gland opening and lyrifissures located in arrangement typical for genus, but poorly visible.

Anogenital region ( Fig. 5B ). Six pairs of genital and three pairs of aggenital setae with two to five branches. Two pairs of anal (10–12) and three pairs of adanal (ad 1, 16–20; ad 2 and ad 3, 12–16) smooth, setiform setae.Adanal setae ad 3 inserted close to anal plates. Lyrifissures iad located in typical arrangement for genus.

Epimeral region. Similar to E. spindleformis sp. n. Shape and number of the apodemes and epimeral borders typical for the genus. Epimeral setal formula 3–1–3–3. Seta 1c long (24–28), setiform, smooth or with one short cilium in basal part; all other setae with two to five branches. Two pairs of tubercles Sa and Sp present on epimeral region.

Gnathosoma . Similar to that of E. spindleformis sp. n. Subcapitulum longer than wide: 65–69×45–49. Hypostomal setae of different morphology: h branched, longest branch 20–22; m (20–22) setiform, curved in basal part, slightly barbed; a (12–14) setiform and smooth.Adoral setae absent on lips. Palp (length 69–73) with setation 0–2–1–3–8(+1ω). Palpal setae (except tarsus) slightly barbed; solenidion thickened, pressed to palptarsus. Chelicera (36–41) with very small tooth on dorsal side. Cheliceral setae long, setiform and barbed; cha (20–24) slightly longer than chb (12–16). Tragardh’s organ long, narrow, with thin distal part, blunt-ended.

Legs. Similar to those of E. spindleformis sp. n. Legs with one simple claw. Formulae of leg setation and solenidia: I (1–5–3–4–20) [1–2–2], II (1–5–3–4–16) [1–1–2], III (2–3–1–3–15) [1–1–0], IV (1–3–2–4–12) [0–1–0]; homology of setae and solenidia indicated in Table 1. Setae smooth or slightly barbed unilaterally. Famulus short, setiform, inserted very close to solenidion ω 2.

Material examined: 30 specimens: SOUTH AFRICA: KwaZulu­Natal: Royal Natal National Park, 28°36'S 29°05'E, in humid soil and decomposed plant material, 14.xii.1982, C.M. Engelbrecht (NMBA 2905.15). Distribution: This species was known from the Palaearctic, Nearctic, sub­Antarctic regions, north-eastern part of the Oriental region, Australia and the Republic of Congo. Remarks: The characters of the specimens of E. flagellifer from South Africa are very close morphologically to the supplementary descriptions of this species (for example by Berlese 1908, 1910; Csiszár & Jeleva 1962; Hammer 1966; Mahunka & Mahunka-Papp 1995). However, E. flagellifer differs slightly from the specimens from other countries and geographical regions in respect of its smaller body size (smaller than 300 µm in South African specimens versus larger than 300 µm in the others), and localization of notogastral setae lm (inserted a little anterior to the level of setae h 3 in South African specimens versus insertion obviously anterior to the level of setae h 3 in the other specimens).

Figures

Fig.5. Eremulus flagellifer: (A) dorsal view, legs not shown; (B) ano-aggenital region;(C) medio-distal part of sensillus; (D) notogastral seta la. Scale bars A, B = 50 μm; C, D = 10 μm.