Otopheidomenis zalelestes Treat, 1955

Prasad, Vikram, 2020, Redescription of females of Otopheidomenis zalelestes Treat, 1955 (Acari: Otopheidomenidae) including details of the leg chaetotaxy, sigilla, and spermatheca, Persian Journal of Acarology 9 (2), pp. 95-128 : 97-98

Otopheidomenis zalelestes Treat, 1955 ( Figs. 1–42 , Tables 1–8)

Female

Idiosoma – Dorsum ( Figs. 1–5 , 25–27 , Tables 1, 2) – Dorsal shield oval, concave laterally in middle, almost totally covered with scale-like patterns, partially cleaved (CLE) bilaterally anterior to sigilla 'sg' partially dividing it into podonotal shield (POS) having a few lateral folds (FOL) and opisthonotal shield (OPS) with several folds. Podonotal shield longer (260–281) than opisthonotal shield (203–212) but width of former (POS) less (264–287) than the latter (299–302). Dorsal idiosoma with 16 pairs of setae of which podonotal shield with 9 pairs of setae (j1, j3, j5, j6, z2, z4, z5, s4, s6); opisthonotal shield with 5 pairs of setae (J2, J5, Z3, Z4, Z5); and 2 pairs of setae (r3 and r5) on lateral integument. Setae s6 and Z5 located on margin of shield. All setae short (11–27) except minute J5 (4–6) and long Z5 (52–60). None of setae with any serrations. Transverse distance between s6-s6 largest (256–260) followed by s4-s4 (243–258) and least between j5-j5 (16–21) indicating that pair of setae j5 are located closest to each other than any other pair of setae on the dorsal shield. Vertical distance between z5-Z3 largest (232–254) followed by J2-J5 (139–149). Different sigilla barely seen in low magnification except for sg medial to the lateral cleavage ( Fig. 1 ) in female # 1 but many like saIII, saIV, saV, saVI, sg on the podonotal shield ( Figs. 25 , 27 ) and saIX, saX, saXI, saXII, saXIII and saXIV on the opisthonotal shield ( Fig. 26 ) seen clearly in high magnifications in females # 1 and 2. Thus, examination of different specimens in high magnifications is necessary if to study and identify the sigilla. Anterior ends of peritremes extending between j3 and z2. Different measurements as given in Tables 1 and 2.

Venter ( Figs. 6–8 , 28–30 , Table 3) – Paired tritosternal lacinae absent and only single, half-moon shaped tritosternal base (TRB) present. Sternal shield (SS) smooth, flying bat-wing shaped, much wider than long, both anterior ends narrowly pointed and extending on anteromedial borders of coxae II, flat or slightly concave anteromedially, concave posterolateral to ST1, irregularly strait or slightly concave posteromedially in between setae ST2, concave laterally between coxae II, smooth, and with 2 pairs of setae (ST1 and ST2) located on margin of shield appearing as they are off the sternal shield. Seta ST3 on integument or on tiny plate. Seta ST4 absent. Transverse distance between setal pair ST1-ST1 much less (49–53 = 51) than ST2-ST2 (81–92 = 87) and ST3-ST3 (110–129 = 119) and vertical distance between ST1-ST2 (46–56 = 52) much more than ST2-ST3 (32–42 = 39). Tip of seta ST1 almost touching base of ST2 and this touching or passing base of seta ST3. Genital shield round around both corners and posteriorly, concave laterally near seta ST5 which is located on integument. Transverse distance between ST5-ST5 97–106 = 101. Anal shield smooth, preanal setae absent, with pair of paraanal and single postanal seta surrounding anus, cribrum lightly present. Opisthosomal setae ZV1 and ZV2 on integument anterior to and JV5 lateral to anal shield. All ventral setae, similar to dorsal setae, smooth and without serrations. Different measurements given in Table 3.

Gnathosoma ( Figs. 9–12 , Table 4) – Dorsal gnathosoma with tectum being round and smooth anteriorly, not greatly elongate but shallow, length (in middle) 16 and width 44. Movable digit of chelicera wide posteriorly, narrow anteriorly, with 5 tiny teeth in distal half and no teeth in posterior half of segment; fixed digit atrophied and very much reduced to a stubby growth. Corniculi elongate, not harpoon-shaped seen in Phytoseiidae . Ventral gnathosoma with pair of capitular setae, 3 pairs of hypostomal setae and capitular gutter with 10–12 denticular rows, each having a few to several tiny anteriorly projected membranous growth giving serrate appearance. Palp tarsus with bifurcate apotele. Number of setae (dorsal, ventral and lateral) on palp segments as: Trochanter = 0, Femur = 6, Genu = 6 and Tibia = 12+ (setae on tarsus not studied, having a round thumb-like structure with several tiny setae on it).

Legs ( Figs. 13–24 , 34–42 , Table 5) – Details of legs I-IV, including chaetotaxy of genua I-IV and tibiae I-IV, are given in Figs. 14–24 , 33, 34 and Table 5. If the leg segments are rotated anteriorly (or posteriorly), commonly seen in Hoyer's mounted specimens, less vertical distance is seen anteriorly and more distance is seen posteriorly if measured from midline of the bases of setae ad1- ad2 and pd1-pd2 ( Fig. 13 , genu I). In this case of genu, setae ad1 and ad2 appear closer to the anterior border (shown with short dark arrow) and setae pd1 and pd2 appear way anterior to the posterior margin of the segment (shown with long dark arrow). In case of genu IV which has 7 setae on it, similar to genu III and pv1 is absent (al1, ad1, ad2, av1; pd1, pd2 and pl1 = 7), a 'ghost seta' is present in one specimen ( Fig. 20 ) giving total count of setae as '8' in place of '7' setae. Tarsus I has numerous setae and not studied as difficult to count. Similar to tarsus IV, each tarsus II and III ( Table 5) has 18 short and simple setae (al1, al2, al3, pl1, pl2, pl3, ad1, ad2, ad3, pd1, pd2, pd3, av1, av2, pv1, pv2, md and mv). However, 4 of these setae (ad2, ad3, pd2 and pd3) on tarsus IV are large, greatly thickened and modified as macrosetae (MS). It should be noted that each tarsus II-IV has well defined three regions having fixed number of setae: (a) Basitarsus (BTA) proximal to lyrifissure of basitarsus having 4 setae (al3, pl3, ad3, pd3); (b) Proximal distitarsus (PDTA), proximal to lyrifissure of PDTA having five setae (al2, pl2, ad2, pd2 and mv); and (c) Distal distitarsus (DDTA), distal to PDTA and proximal to pretarsus having 9 setae (al1, pl1, ad1, pd1, av1, av2, pv1, pv2 and md). While lyrifissure of basitarsus is present all around the segment, the lyrifissure of proximal distitarsus is not present all around the segment.

Figures

Figure 1. Otopheidomenis zalelestes Treat, 1955 (VP collection) – Idiosoma (ID) in low magnification with 16 pairs of setae of which 14 pairs (j1, j3, j5, j6, J2, J5, z2, z4, z5, Z3, Z4, Z5, s4, s6) on dorsal shield (DS) and 2 pairs (r3 and r5) on integument. A lateral cleavage (CLE) partially dividing podonotal shield (POS) with 9 pairs of setae from opisthonotal shield (OPS) with 5 pairs of setae where seta s6 present laterally and sigilla sg present medially. Several folds (FOL) also seen (Treat slide # 2, female # 1, photo # 5 - Fig. 1, 200×).

Figures 2–3. Otopheidomenis zalelestes Treat, 1955 (VP collection) in high magnification – 1. Idiosoma setae j1, j3, j5, z2, z4, z5, and s4 on podonotal shield and r3 on integument; 2. Opisthonotal shield with setae J5, Z3, Z4 and Z5. Setae j6, J2, s6 and r5 are not photographed. Anterior end of peritreme (PER) extends between setae j3 and z2 (Treat slide # 1, female # 1, photo # 10 - Fig. 2 and photo # 11 - Fig. 3, 400×).

Figures 4–5. Otopheidomenis zalelestes Treat, 1955 (VP collection) in high magnification – 4. Left anteromedial idiosoma with setae j5, j6, z4, z5, s4, s6 on podonotal shield and r3 and r5 on integument; 5. Posteromedial idiosoma with setae j6, J2, and s6. Elongate sigilla sg seen medial to lateral cleavage (Treat slide # 1, female # 1, photo # 14 - Fig. 5 and photo # 13 - Fig. 6, 400×).

Figure 6. Otopheidomenis zalelestes Treat, 1955 (VP collection) – Ventral view of idiosoma in low magnification with tiny tritosternal base (TRB) without laciniae, wing-shaped sternal shield (SS), setae ST1-ST3, genital shield (GS) with seta ST5, metapodal shield (MPS) and opisthosomal setae ZV1 and ZV2. Anal shield and seta JV5 not photographed (Treat slide # 2, female # 1, photo # 7 - Fig. 6, 200×).

Figures 7–8. Otopheidomenis zalelestes Treat, 1955 (VP collection) – Ventral idiosoma in high magnification with tiny moon-shaped tritosternal base (TRB) without laciniae is concave anteriorly and convex posteriorly. 7. Wing-shaped sternal shield (SS) with setae ST1 and ST2 on it and ST3 on integument; 8. Anal shield (AS), and opisthosomal setae ZV1 and ZV2 (Treat slide # 1, female # 1, photo # 15 - Fig. 7 and photo # 17 - Fig. 8, 400×).

Figures 9–10. Otopheidomenis zalelestes Treat, 1955 (VP collection) – Dorsal (Fig. 9) and ventral (Fig. 10) gnathosoma in high magnifications with movable digits (MD), pair of capitular setae (CAP), and 3 pairs of hypostomal setae (HY1-HY3). Top insets, left and right, enlarged movable digits (MD) with 5 denticles (DEN) on each (Treat slide # 1, female # 1, photo # 19 - Fig. 9 and photo # 20 - Fig. 10, 400×).

Figures 11–12. Otopheidomenis zalelestes Treat, 1955 (VP collection) – Dorsal (Fig. 11) and ventral (Fig. 12) palps in high magnifications with associated setae on: TR (Trochanter) = without setae, FE (Femur) = with 6 setae, GE (Genu) = with 6 setae, TI (Tibia) = with 12 setae, and TA (Tarsus) = with many setae and bifurcate apotele, APO (Treat slide # 1, female # 1, photo # 21 - Fig. 11 and photo # 22 - Fig. 12, 400×).

Figures 13–14. Otopheidomenis zalelestes Treat, 1955 (VP collection) – Genu and tibia of left leg I in dorsal (Fig. 13) and ventral (Fig. 14) views with associated setae in high magnifications [GE: 5 + 3 = 8 setae; TI: 5 + 3 = 8 setae]. Note anterior rotation of genu and tibia due to which setae ad1 and ad2 have moved close to anterior margin (Treat slide # 1, female # 1, Fig. 13 - photo # 23 and Fig. 14 - photo # 24, 400×).

Figures 15–16. Otopheidomenis zalelestes Treat, 1955 (VP collection) – Genu and tibia of left leg II in dorsal (Fig. 15) and ventral (Fig. 16) views with associated setae in high magnifications. Note absence of setae av1 and pv1 on genu II and absence of ad2 on tibia II. Thus, Ge II = 6 setae (5 + 1) and Ti II = 7 setae (4 + 3) (Treat slide # 1, female # 1, Fig. 15 - photo # 25 and Fig. 16 - photo # 26, 400×).

Figures 17–18. Otopheidomenis zalelestes Treat, 1955 (VP collection) – Genu and tibia of left leg III in dorsal (Fig. 17) and ventral (Fig. 18) views with associated setae in high magnifications. Note absence of seta pv1 on genu III and absence of seta ad2 on tibia III. Thus, Ge III = 7 setae (5 + 2) and Ti III = 7 setae (4 + 3) (Treat slide # 1, female # 1, Fig. 17 - photo # 27 and Fig. 18 - photo # 28, 400×).

Figures 19–20. Otopheidomenis zalelestes Treat, 1955 (VP collection) – Genu and tibia of left leg IV in dorsal (Fig. 19) and ventral (Fig. 20) views with associated setae in high magnifications [GE: 4 + 3 = 7 setae; TI: 3 + 4 = 7 setae]. Note a ghost seta (in rectangular box) on genu IV not included in this count (Treat slide # 1, female # 1, Fig. 19 - photo # 29 and Fig. 20 - photo # 30, 400×).

Figures 21–22. Otopheidomenis zalelestes Treat, 1955 (VP collection) – Tarsus of left leg III in dorsal (Fig. 21) and ventral (Fig. 22) views with associated setae [BTA: 4 setae (ad3, pd3, al3, pl3, proximal to LYRF-BTA); P-DTA: 5 setae (ad2, pd2, al2, pl2, mv around LYRF-PDTA); and D-DTA: 9 setae (ad1, pd1, al1, pl1, av1, av2, pv1, pv2, md); Tarsus III = 18 setae] (Treat slide # 1, female # 1, Fig. 21 - photo # 39 and Fig. 22 - photo # 40, 400×).

Figures 23–24. Otopheidomenis zalelestes Treat, 1955 (VP collection) – Tarsus of left leg IV in dorsal (Fig. 23) and ventral (Fig. 24) views with associated setae [BTA: 4 setae (MS-ad3, MS-pd3, al3, pl3, proximal to LYRF-BTA); P-DTA: 5 setae (MS-ad2, MS-pd2, al2, pl2, mv around LYRF-PDTA); and D-DTA: 9 setae (ad1, pd1, al1, pl1, av1, av2, pv1, pv2, md); Tarsus IV = 18 setae] (Treat slide # 1, female # 1, Fig. 23 - photo # 41 and Fig. 24 - photo # 42, 400×).

Figure 25. Otopheidomenis zalelestes Treat, 1955 (VP collection) – Anterior dorsal shield showing different sigilla on the podonotal shield. Note left lateral cleavage (CLE) which ends anterior to sigilla sg anterior to which many sigilla are present but only some (saIV, saV, saVI, and ss) are clearly seen (Treat slide # 2, female # 1, photo # 3, 200×).

Figure 26. Otopheidomenis zalelestes Treat, 1955 (VP collection) – Posterior dorsal shield showing different sigilla on the opisthonotal shield. Note left lateral cleavage (CLE) which ends anterior to sigilla sg and posterior to which 4 sigilla (saIX, saX, saXI, and saXII) are present. Sigilla saXIII and saXIV between setae Z4 and Z5 are barely seen (Treat slide # 2, female # 1, photo # 3, 200×).

Figures 27–30. Otopheidomenis zalelestes Treat, 1955 (VP collection) – 27. Some sigilla of anterior dorsal shield right to setae j5 and z5 (Treat slide # 2, female # 2, photo # 13, 400×); 28–29. Sternal shield and genital shield (Treat slide # 2, female # 1, photos # 11 and 12, 400×); 30. Anal shield (Treat slide # 2, female # 2, photo # 18, 400×).

Figures 31–37. Otopheidomenis zalelestes Treat, 1955 (OSAL 0104319) – 31–32. Tubular insemination system in female (L-SPER = left spermatheca; R-SPER = right spermatheca) without showing central vesicular sacculus: Fig. 31 (top, photo # 22) - Right; Fig. 32 (bottom, photo # 24) (Left and right, both figures in 400×); 33–37. Chaetotaxy of left legs I-IV: 33. Genu and tibia I (photo # 24); 34. Genu and tibia II (photo # 26); 35. Genu and tibia III (photo # 28- 1); 36. Genu and tibia IV (photo # 30); 37. Tarsus IV (photo # 42). Note setae ad2, ad3, pd2, and pd3 being the 4 macrosetae [BTA = basitarsus, GOS = ghost seta on genu IV, DDTA = distal distitarsus, LYRFIS-BTA = lyrifissure of BTA, LYRFIS-PDTA = lyrifissure of PDTA, MS = macroseta, PDTA = proximal distitarsus, PRT = pretarsus] (Treat slide # 1, female # 1, 400×).

Figures 38–42. Otopheidomenis zalelestes Treat, 1955 – Chaetotaxy of legs I-IV: 38. Genu and tibia I (photo # 24); 39. Genu and tibia II (photo # 26); 40. Genu and tibia III (photo # 28-1); 41. Genu and tibia IV (photo # 30); 42. Tarsus IV (photo # 42). Note setae ad2, ad3, pd2, and pd3 being the 4 macrosetae [BTA = basitarsus, GOS = ghost seta on genu IV, DDTA = distal distitarsus, LYRFIS-BTA = lyrifissure of BTA, LYRFIS-PDTA = lyrifissure of PDTA, MS = macroseta, PDTA = proximal distitarsus, PRT = pretarsus] (Treat slide # 1, female # 1, 400×).