Eremulus southafricanensis, Ermilov & Hugo-Coetzee, 2012

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 : 564-566

Eremulus southafricanensis sp. n.

Fig. 4

Etymology: Named after the country of origin, South Africa.

Diagnosis: This species is distinguished from others by the following combination of characteristics: body size 514–547×282–325; rostrum weakly protruding anteriorly; transcostula present; prodorsal setae smooth; interlamellar setae similar in length to rostral and lamellar setae; sensilli flagelliform, ciliate; 11 pairs of notogastral setae, thin basally and widened medially, smooth; setae lp directed laterally, h 1 directed postero-medially; setae lm inserted below the level of insertions of h 3; aggenital setae branched; adanal setae ad 1 and ad 2 longer than ad 3; epimeral setae 1c long and setiform.

Description:

Measurements. Body length 530 (holotype, female), 514–547 (mean 528, 12 paratypes); body width 303 (holotype, female), 282–325 (mean 301, 12 paratypes).

Integument ( Fig. 4A ). Body yellow-grey-brownish. Body and legs covered by secretion granules (diameter up to 2 µm). Prodorsum with foveolae. Foveolate band on notogaster with numerous foveolae. Foveolate band anterior to genital plates present.A small concave region is present between rows of notogastral setae c and la.

Prodorsum ( Fig. 4A, C ). Rostrum weakly protruding anteriorly. Costulae long, narrow, straight. Transcostula present.All prodorsal setae setiform, smooth, inserted on tubercles. Rostral, lamellar and interlamellar setae similar in length (57–65), exobothridial setae shorter (32–41). Rostral setae inserted in lateral position on prodorsum. Sensilli (168–176) flagelliform, covered by short cilia. Bothridial margins with teeth (visible under high magnification).

Notogaster ( Fig. 4A, D ). Anterior border straight. One pair of humeral condyles and cristae present, but they are not very obvious. Eleven pairs of notogastral setae (p 3 inserted in margino-ventral position) of medium size, approximately similar in length (57–69; only p 1 and p 2 a little longer, 69–77; and p 3 a little shorter, 53–57), thin basally and widened medially, curved in basal part, smooth. Setae lp always directed laterally and h 1 always directed postero­medially. Setae lm inserted behind the level of insertions of h 3. Opisthonotal gland opening and lyrifissures located in arrangement typical for genus, but poorly visible.

Anogenital region ( Fig. 4B ). Six pairs of genital and three pairs of aggenital setae with two to five branches. Setae g 1 setiform, not branched or with one short cilium. Two pairs of anal (24–32) and three pairs of adanal (ad 1 and ad 2, 57–69; ad 3, 36–49) smooth, setiform setae. Adanal setae ad 3 distant from anal plates. Lyrifissures iad located in arrangement typical for genus.

Epimeral region. Similar to that of E. spindleformis sp. n. Shape and number of apodemes and epimeral borders typical for genus. Epimeral setal formula 3–1–3–3. Setae 1c long (57–69), setiform and smooth; all other setae with two to four branches. Two pairs of strongly developed tubercles, Sa and Sp present on epimeral region.

Gnathosoma . Similar to that of E. spindleformis sp. n. Subcapitulum longer than wide: 135–143×82–90. Hypostomal setae of different morphology: h branched, longest branch 41–49; m (41–49) setiform, curved in basal part, slightly barbed; a (32–36) setiform and smooth. Adoral setae absent on lips. Palp (length 65–69) with setation 0–2–1–3–8(+1ω). Palpal setae (except tarsus) slightly barbed; solenidion thickened, pressed to palptarsus. Chelicera (135–143) with small tooth on dorsal side. Cheliceral setae long, setiform and barbed; cha (32–36) longer than chb (24). 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 for 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.

Holotype: ♀ SOUTH AFRICA: Limpopo: Lenyenye , 23°03'S 30°22'E, in dry loam soil with decomposed leaf litter under indigenous trees, 31.viii.1982, C.M. Engelbrecht ( NMBA 2344.12.1).

Paratypes: 12, same data as for holotype (5 NMBA, 4 SZMN, 3 PC) .

Remarks: E. southafricanensis sp. n. is clearly distinguishable from the other known species of this genus by the specific orientation of two pairs of notogastral setae (lp directed laterally and h 1 directed postero-medially).

Figures

Fig. 4. Eremulus southafricanensis sp. n.: (A) dorsal view, legs not shown; (B) ano-aggenital region; (C) medio-distal part of sensillus; (D) notogastral seta la. Scale bars A, B = 100 μm; C, D = 20 μm.