Spinibdella thori (Meyer & Ryke)

Theron, Elizabeth Omukunda Pieter D & Ueckermann, E A, 2012, Spinibdella Thor (Acari: Bdellidae) from southern Africa: descriptions of five new species and the redescription of S. thori (Meyer & Ryke), Zootaxa 3304, pp. 1-24 : 18-22

Spinibdella thori (Meyer & Ryke)

Figs 45–52

Bdella thori Meyer & Ryke, 1959: 375

Description. Female (n = 171) Dimensions: color in life is cream. Length including gnathosoma 567–852; width 210–355; length of gnathosoma 172–212; length of chelicera 153–206; length of DHS 11–19; length of palp segments: I 9–12; II + III 122–143; IV 15–21; V 27–38; des 160–227; ves 86–143; length of legs: I 199–300; II 186–298; III 223–377; IV 286–458; length of setae: vi 100–120; ve 36–42; sci 94–105; sce 36–42, c1 38–46; c2 42–54; d 35–46; e 41–48; f1 43–56; f2 39–50; h1 51–71; h2 51–69; distance: vi– vi 38–52; first interspace (c1 to d) 63–86.

Gnathosoma ( Figs 45–47 ). Chelicerae have a pair of setae each and fine longitudinal striations. Proximal seta 1.6 times distal one. Both movable and fixed chelae straight but former longer as shown in figure 45. Palp ( Fig. 46 ) extends beyond hypostome. Palp chaetotaxy as follows from trochanter to tibiotarsus, 0-8(9)-1-4-4 sts, 1 ω, des, ves. Gnathosomal base has strong fine transverse striations as shown in figure 47, while hypostome has two pairs of strong ventral setae, one pair of DHS setae and weak longitudinal striations. Two pairs of adoral setae resent on the lips.

Dorsum ( Fig. 48 ). Simple naso median eye posterior to naso. Two pairs of trichobothria on prodorsum. Setae ve slightly curved and simple while sce are straight and thicker than ve. Center of prodorsum has fine, continuous, transverse striations. Two pairs of detectable eyes separated by oblique to longitudinal striations and a distance equal to the diameter of smaller posterior pair. All setae simple, sejugal groove conspicuous as shown in figure 48.

Venter ( Fig. 49 ). Ventral setae simple and blunt. Thirty four aggenital setae, first pair between coxa IV. Ten pairs of equal genital setae linearly arranged, nine on one plate and 11 on another. Three pairs of genital discs, proximal pair largest, two pairs arranged in first ½ of vestibule and third small pair in the distal ½. Three pairs of anal setae present. Ovipositor with 18 setae as shown in figure 49.

Legs ( Figs 50–51 ). Legs shorter than idiosoma. Genua I–III have duplex setae medially. Tibiae I have two attenuate solenidia, one of which is blunt and reduced, an attenuate peg and trichobothrium in distal half ( Fig. 50 ). Tibiae II with a deeply recessed blunt solenidion distally ( Fig. 51 ). Tibia III has an attenuate solenidion in distal position. Tarsi I have one attenuate and two blunt solenidia, former proximally and later distally. Tarsi II have a simple peg in addition to two blunt solenidia. Claws shorter than pretarsi and rayed. Leg chaetotaxy as follows: coxae I–IV 10-8 (6)-6(8)-6 sts; trochanters I–IV 1-1 -2-1 sts; basifemora I–IV 10 (11)-8(9-11)-8-3 sts; telofemora I–IV 7 (6-9)-8(6)-5(4)-6 sts; genua I–IV 6 sts 1duplex -6 sts, 1duplex -6 sts 1duplex – 7 sts; tibiae I–IV 14 (11–13) sts, 2φ, 1ĸ, 1tr -14(11–13) sts, 1φ -14 (11–14) sts, 1φ -15(13–14) sts, 1tr; tarsi I–IV 28 (28–31) sts, 3ω -28 (28–31) sts, 2ω, 1 ĸ -25(24) sts, 1tr -27 sts, 1tr.

Male (n = 2). ( Fig. 52 ). Dimensions: length including gnathosoma 463–493; length of gnathosoma 157–168; width 162–172; length of chelicerae 139–141; length of palp segments: I 10–12; II + III 105–107; IV 17; V 29; des 153–155; ves 96–107; length of legs: I 201–214; II 172–182; III 222–225; IV 280–283; length of setae: DHS vi broken off; 13; ve 29–31; sce 31; c 1 29–31; c 2 31–33; d 27; e 29; f1 33, f2 32; h1, 42; h2 43; distance: vi– vi 38; first interspace (c1 to d) 48–54. Except for small size and difference in genital area, males are similar to females. Amphioid sclerites characteristic of this species as seen in figure 52.

Tritonymph (n = 50). Dimensions: Total length including gnathosoma 412–657; width 172–229; length of gnathosoma 145–212; length of chelicerae 134–172; DHS 10–15; length of palp segments: I 10–12; II + III 92 –130; IV 10–19; V 25–33; des 139–191; ves 78–115; length of legs: I 170–230; II 167–216; III 251–265; IV 228–336; length of setae: vi 92 –103; ve 29–34; sci 94–107; sce 31–36; c 1 29–38; c2 38–48; d 29–37; e 34–38; f1 36–41; f2 36–42; h1 43–52; h2 44–47; distance vi– vi 33–44; first interspace (c1 to d) 50–71.

This developmental stage has seven pairs of blunt, equal aggenital setae, first pair between coxae IV, unpaired setae anterior to genital plate. Five pairs of blunt genital setae arranged linearly on genital plates. Three pairs of genital discs occur in vestibule; two pairs in anterior half and one pair in posterior half. Two pairs of anal setae ventrally. Palp chaetotaxy differs from that of female in that palp basifemora bear 7 setae. Leg chaetotaxy as follows: coxae I–IV 8-6 -6-4 sts; trochanters I–IV 1-1 -2-1 sts; basifemora I–IV 7-7 -6-3 sts; telofemora I–IV 5-4 -4-4 sts; genua I–IV 4 sts, 1duplex -4 sts, 1duplex -4 sts 1duplex -4 sts; tibiae I–IV 8 sts, 2φ, 1ĸ, 1tr -8 sts, 1φ - 8 sts, 1φ - 8(9) sts, 1tr; tarsi I–IV 23 sts, 3ω-23 sts, 2ω, 1 ĸ -21 sts, 1tr -20 sts, 1tr.

Deutonymph (n = 32). Dimensions: Length including gnathosoma 359–610; width 196–248; length of gnathosoma 124–152; length of chelicerae 105–138; length of DHS 10–13; length of palp segments: I 10; II + III 82 –105; IV 13–15; V 23–29; des 117–145; ves 54–82; length of legs: I 116–204; II 149–160; III 182–239; IV 201–273; length of setae: vi 86 –115; ve 29–33; sce 29–39; c 1 29–33; c2 36–40; d 24–31; e 28–29; f1 32–35; f 2 30–39; h1 42–45; h2 39–41; distance: vi– vi 25–29; first interspace (c1 to d) 48–57.

This ontogenetic stage has 15 equal blunt aggenital setae, first pair between coxae IV, unpaired seta anterior to genital plates. It has one pair of blunt genital setae and two pairs of genital discs. Two pairs of anal setae occur ventrally. Palp chaetotaxy differs from that of female by palp basifemora having five setae. Leg chaetotaxy follows: coxae I–IV 6-4 -5-2 sts; trochanter I–IV 1-1 -2-1 sts; basifemora I–IV 5-5 -4-1 sts; telofemora I–IV 5-4 -4-4 sts; genua I–IV 4 sts, 1duplex -4 sts, 1duplex -4 sts, 1duplex -4 sts; tibiae I–IV 6 sts, 2φ, 1ĸ, 1tr -5 sts; 1φ-6 sts, 1φ-7 sts, 1tr; tarsi I–IV 19 sts, 3ω-20 sts, 2ω, 1 ĸ -21 sts, 1tr - 17 sts, 1tr.

Protonymph (n = 34). Dimensions: length including gnathosoma 410–468; width 159–220; length of gnathosoma 114–137; length of chelicerae 103–125; length of palp segments: I 6; II + III 75 –86; IV 12–15; V 23–25; des 105–136; ves 54–67; DHS 8–12; length of legs: I 130–182; II 133–172; III 174–229; IV 162–203; length of setae: vi 76 –118; ve 23–29; sci 88–95; sce 23–29; c 1 23–32; c2 34–44; d 22–25; e 25–26; f 1 30–33; f 2 27–30; h1 40–42; h 2 38–30; distance: vi– vi 23–28; first interspace (c1 to d) 38–48.

This stage has eight aggenital setae, first pair between coxae IV, genital setae absent and has one pair of genital discs. Anal plate bordered by two pairs of anal setae ventrally. Palp basifemora differ from that of female by having two setae. Leg chaetotaxy differs from that of female as follows: coxae I–IV 3 bts, 1 sts -2-3-0 sts; trochanter I–IV, 1-1-1-0 sts; basifemora I–IV 2-2 -1-0 sts; telofemora I–IV 5-3 -5-0 sts; genua I–IV 4 sts, 1 duplex -4 sts, 1duplex -4 sts, 1duplex-0 sts, tibiae I–IV 4 sts, 2φ, 1ĸ, 1tr -5 sts, 1φ -5 sts, 1φ -1 sts; tarsi I–IV 16 sts, 2ω-16 sts, 2ω, 1 ĸ – 16 sts, 1tr -7 sts.

Larva (n = 17). Dimensions: Length including gnathosoma 254–308; width 105–147; length of gnathosoma 90–115; length of chelicerae 84–105; DHS 6; length of palp segments: I 6; II + III 57 –65; IV 12–13; V 17–19; des 67–92; ves 38–46; length of legs: I 105–109; II 92 –103; III 115–168; length of setae: v i 71 –76; ve 19–25; sci 99; sce 19–29; c 1 21–23; c 2 29–34; d 19–23; e 17–23; f 1 21–25; f 2 18–22; h 1 31–38; h2 34–49; distance vi– vi 17–19; first interspace (c1 to d) 23–36.

This stage is characterized by three pairs of legs and undeveloped genital region. Two pairs of anal setae present. Femora not subdivided. Palp femur has two setae, trochanter without setae. Leg chaetotaxy differs from that of female as follows: coxae I–III 2-1 -2 sts; trochanter, I–III 0-0-0 sts; femora I–III 6-6 -5 sts; genua I–III 4 sts 1duplex -4 sts, 1duplex -4 sts, 1duplex; tibiae I–III 5 sts, 2φ, 1ĸ -5 sts, 1ĸ-7 sts, 1φ; tarsi I–III 13 sts, 2ω-15 sts, 1ω, 1 ĸ -11 sts, 1tr.

Material examined. SOUTH AFRICA, Eastern Cape Province: Holotype female, Bathurst, from an unidentified bush, 6 June 1956, Coll. P. Graham; North West Province: 22 females, 3 tritonymphs, one deutonymph and 2 larvae, Boskop Dam, Potchefstroom, from debris under Acacia karroo , 11 January 1996 to 1 November 1996, Coll. J. van der Schyff; 5 females, 1 deutonymph and 1one tritonymph, North-West University Campus, Potchefstroom, in soil, 5 November 1962, Coll. G.C. Loots; 27 females, 2 tritonymphs, 6 deutonymphs, 3 protonymphs and 2 larvae, North-West University Campus, Potchefstroom, from debris under A. karroo Hayne , ( Fabaceae ), 22 July 1970 and 10 October 1970, Coll. J den Heyer; 5 female, 4 tritonymphs, 1 deutonymph, 1 protonymph and 1 larva, North-West University Campus, Potchefstroom, from litter under Dombeya rotundifolia (Hochst.) Planch. (Sterculiaceae) , 10 November 1970 and 19 March 1971, Coll. J. den Heyer; 3 females, 2 tritonymphs and 3 protonymphs, North-West University Campus, Potchefstroom, from debris under Euphorbia L. sp. ( Euphorbiaceae ), 9 April 1971, Coll. J den Heyer; 1 female, Bodenstein, Coligny, from debris under Salix sp., 3 March 1973, Coll. J. den Heyer; 1 female, 2 deutonymphs, 3 protonymphs and 1 larva, North-West University Campus, from soil, 15 January 1974, Coll. J. den Heyer; 2 females, 1 tritonymph, 1 deutonymph and 1 larva, Bodenstein, Coligny, from litter under Salix L. ( Salicaceae ) sp., 20 January 1974, Coll. J. den Heyer; 3 females, Zeerust, from soil, 9 February 1997, Coll. M. Erasmus; 3 females, 3 deutonymphs and 1 larva, Boskop Dam, from debris under A. karroo Hayne , ( Fabaceae ), 19 February 1997, Coll. P.D. Theron; 7 females, 1 tritonymph, 3 protonymphs and 1 larva, Boskop Dam, from debris under A. karroo Hayne , ( Fabaceae ), 6 November 1998, Coll. E.N. Omukunda; 23 females, 7 tritonymphs, 2 deutonymphs and 3 protonymphs, Boskop Dam, from debris under A. karroo Hayne , ( Fabaceae ), 9 November 1998, Coll. E.N. Omukunda; 3 females, Zeerust, from Searsia sp., 0 2 March 1997, Coll. M. Erasmus. Limpopo Province: 1 deutonymph, 10km from Polekwane, from debris under A. karroo Hayne , ( Fabaceae ), 4 October 1970, Coll. J. den Heyer; 1 female, 2 tritonymphs, 5 deutonymphs, 5 protonymphs, 1 larva, Lajuma farm near Mara, from moss, fern and forest floor, 14 November 1970, Coll. J. den Heyer; 8 females, 1 deutonymph and 3 protonymphs, University of the North Campus, from mixed vegetation, 5 November 1970, Coll. J. den Heyer; 22 females, 7 tritonymphs and 1 deutonymph, Rietkolk near Polokwane from debris under Acacia rehmanniana Schinz (Fabaceae) and Searsia pyroides Burch. , (Anacardiacea), 11 April 1971, Coll. J. den Heyer; 3 females and 3 tritonymphs, bank of Blood River, 10 km from Polokwane, from Acacia rehmanniana Schinz (Fabaceae) and Protasparagus Oberm. sp. ( Liliaceae ), 11 April 1971, Coll. J. den Heyer; 16 females, 1 tritonymph, 2 deutonymphs and 1 larva, Polokwane, from debris under A. karroo Hayne , ( Fabaceae ), 29 April 1971, Coll. J.den Heyer; 1 female and 1 deutonymph, Limpopo River, Soutpansberg district, 23 May 1971, Coll. C.C. Straub; 5 females, 3 tritonymphs, 1 deutonymph and 1 larva, alongside Chuniz road, Polokwane, from debris under Acacia Mill. sp, ( Fabaceae ), 24 May 1971, Coll. J. den Heyer; 4 females and 1 tritonymph, University of the North Campus, debris from a nearby hill, 17 March 1972, Coll. J. den Heyer; 6 females, 5 tritonymphs, 7 protonymphs and 4 larvae, Breslau farm, Limpopo River, from debris under Xanthocercis zambesiaca (Bak.) Dumaz-le-Grand ( Fabaceae ), 16 April 1972, Coll. C.C. Straub; 5 females, Polokwane, from debris under Acacia tortilis (Forssk.) Hayne , ( Fabaceae ) 17 November 1973, Coll. J. den Heyer; 2 females and 2 tritonymphs, Rooiberg, from Maytenus Molina sp. ( Celastraceae ), Coll. P.D. Theron, 0 4 February 1988. Mpumalanga Province: 6 females and 3 deutonymphs, 39 km from Loskop Dam Nature Reserve, from debris of Maytenus heterophylla (Eckl. & Zeyh.) N.K.B. Robson , ( Celastraceae ) Ozoroa paniculosa (Sond.) R. & A. Fernandes ( Anacardiaceae ) and Dombeya rotundifolia (Hochst.) Planch. (Sterculiaceae) , 17 November 1971, Coll. J. den Heyer; 1 female, Loskop Dam, from debris under Searsia lancea (L. F.), (Anacardiacea), 2 March 1973, Coll. J. van Huyssteen; KwaZulu/ Natal Province: 2 females, Fanies Island, St. Lucia Lake, from soil, 16 September 1972, Coll. G.C. Loots; 1 female, 3 protonymphs and 1 larva, 20km from Jozini, from soil, 20 September 1972, Coll. G.C. Loots; one female, 10km from Jozini to Pongola, from soil, 21 September 1972, Coll. G.C. Loots; Northern Cape Province: 8 tritonymphs and 4 deutonymphs, 21 km south of Springbok, from litter under Antizoma miersiana Harv. (Menispermaceae) , 27 September 1973, Coll. D. Botha; one female. Goegab Nature Reserve, from debris under Zygophylum L. sp. ( Zygophyllaceae ), August 1993, Coll. H. Kruger; 3 females and 1 tritonymph, Nababeep, from Berkheya spinosissima (Thunb.) Willd (Asteraceae) , 29 August 1996, Coll. H. Kruger; 1 female, Sariesaam, from Mesembryanthemaceae, Coll. H. Kruger , 29 August 1996. Free State Province: 1 female, Marquard-Winburg road, from humus, 20 January 1974, Coll. C.A.J. van Rensburg; Western Cape Province: 2 females, Kleinmond, from soil, 11 December 1976, Coll. J. den Heyer; 4 females, 1 deutonymph and 1 larva, Betty’s Bay, from soil, 21 December 1976, Coll. J. den Heyer; 1 female, 2 males, 1 tritonymph and 1 larva, Cape Point, Cape of Good Hope Nature Reserve, from debris under a bush, 30 December 1998, Coll. P.D. Theron.

Remarks. Atyeo (1963) was of the opinion that S. thori (Meyer & Ryke) may be synonymous with S. ornata Atyeo, 1960 . The characters that distinguish the females of these two species are the presence of 9 setae on the palp basifemur and only a blunt solenidion on tibia II of S. thori instead of 8 setae on the basifemur and a blunt and an acute solenidion on tibia II of S. ornata . Atyeo (1963) was of the opinion that the discovery of a male of S. thori may solve this problem. During this study two male specimens were found and it differs in the shape of the amphioid sclerites and the presence of 12–13 pairs of genital setae instead of 17 pairs in S. ornata . Thus S. thori is a valid species.

Figures

FIGURES 45 – 49. Spinibdella thori Meyer & Ryke: 45. Female chelicera; 46. Female palp; 47. Female hypostome; 48. Female prodorsum; 49. Female ovipositor.

FIGURES 50 – 52. Spinibdella thori Meyer & Ryke; 50. Female leg I; 51. Female leg II; 52. Male genitalia.