Atractides damkoehleri K. Viets 1916
Creators: name: Pešić, Vladimir
name: Smit, Harry
name: Gerecke, Reinhard
Publisher: name: Zenodo
Year: 2011
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Arachnida
Trombidiformes
Hygrobatidae
Atractides
Atractides damkoehleri

description: Atractides damkoehleri (K. Viets, 1916)
(Figs. 1–5)
Megapus damkoehleri K. Viets 1916: 271.
Syn. A. ugandensis (Lundblad, 1927), A. duricorius (Walter & Bader, 1952): K.O. Viets 1964a.
Material examined. South Africa, Western Cape province: SA 1 0/3/1; SA 3 0/1/0; SA 4 0/1/0; SA 5 1/0/0; SA 6 1/1/0; SA 8 1/0/0; SA 10 0/2/0; DC 107 84 2/1 /0; DC109 84 1/0/0. KwaZulu-Natal province: SA 12 0/3/0 (0/1/0 mounted); SA 13 6/9 /0; SA 15 1/6 /0; SA 16 7/4 /0; SA 17 1/0/0; SA 18 13/11 /1; SA 19 1/4 /0; SA 20 8/10 /0 (1/1/0 mounted); SA 21 0/2/0; SA 22 1/7 /0; SA 23 0/1/0; SA 24 1/2 /0; DC 89 84 11/11 /0; DC 90 84 1/0/0; DC 91 84 0/1/ 0; DC 92 84 8/4 /0; DC 93 84 1/0/0. Limpopo province: SA 25 7/2 /0. Mpumalanga province: DC 76 84 0/1/0; DC 78 84 5/13 /1 (0/1/1 mounted); DC 83 84 0/2/0; DC 84 84 13/27/0; DC 85 84 1/5 /0 (1/1/0 mounted); DC 86 84 5/4 / 0.
General features. Dorsal integument striated; muscle attachments unsclerotized; glandularia enlarged by secondary sclerotization. Coxal field: posterior margin Cx-I strongly convex, apodemes of Cx-II directed laterally. Genital field: Ac in triangular position. Excretory pore smooth; Vgl-1 fused to Vgl-2. Palp without sexual dimorphism, P-2 and -3 ventral margin straight, P-4 slender, sword seta slender, halfway between ventral hairs. I-L-5 proximally subrectangular, distally protruding near insertion S-1, S-1 and S-2 interspaced, S-1 obtusely truncate, not thickened distally, S-2 basally enlarged, bluntly pointed; I-L-6 stout, curved, inflated proximally, from the centre to the claw furrow with parallel dorsal and ventral margins; leg claw without dorsal clawlets.
Morphology. Male (SA 20, in parentheses DC 85 84): Idiosoma L/W 509 (444)/428 (322); glandularia maximum diameter 37 (34); coxal field L 288 (286); Cx-III W 317 (307); Cx-I+II mL 123 (102), lL 200 (191). Genital field (Fig. 1A, 3A): anterior margin with a border of secondary sclerotization convexely protruding, posteriorly indented; L/W 94 (88)/116 (101); L Ac 1-3: 35 (27), 39 (29), 42 (30).
Palp (Figs. 1C, 4B): total L 255 (254), dL: P-1, 20 (25); P-2, 55 (52); P-3, 66 (65); P-4, 85 (84); P-5, 29 (28); L ratio P-2/P-4, 0.65 (0.62); capitulum vL 104 (86); chelicera total L (163).
I-L (Figs. 1B, 4A): I-L-5 dL 153 (152), vL 112 (106), dL/vL ratio 1.37 (1.43), HB 48 (46), dL/HB 3.2 (3.3), S- 1 L 79 (77), L/ W 9.2 (8.4), S-2 L 69 (71), L/ W 6.0 (5.6), distance S-1-2, 15 (10), L ratio S-1/2, 1.15 (1.09); I-L-6 L 106 (107), HB 22 (22), L/HB ratio 4.75 (5.0); L ratio I-L-5/6, 1.44 (1.42).
Female (SA 20, in parentheses SA 12, in square parentheses DC 85 84). Idiosoma L/W 669 (756)/544 (641); glandularia maximum diameter 42 (43) [29]; coxal field L 356 (369) [311]; Cx-III W 408 (464) [367]; Cx-I+II mL 122 [119], lL 228 [231]. Genital field (Figs. 2B, 3B): L/W 171 (199) [140]/162 (188) [147]; pregen prominent, curved, W 110 (115) [55]; genital plate L 122–123 (130) [109]; L Ac 1–3: 48–49 (54–57) [39–40], 57–60 (52–54) [43–45], 34–45 (49) [35–39].
Palp (Figs. 1D, 4D): total L 333 (358) [347], dL: P-1, 30 (34) [34]; P-2, 69 (77) [77]; P-3, 93 (99) [95]; P-4, 106 (109) [103]; P-5, 35 (39) [38]; L ratio P-2/P-4, 0.65 (0.71) [0.75]; capitulum vL 128 (141); chelicera total L 219 (250).
I-L (Figs. 2A, 4C): I-L-5 dL 215 (237) [201], vL 149 (172) [148], dL/vL ratio 1.44 (1.38) [1.36], HB 62 (72) [58], dL/HB 3.5 (3.3) [3.5], S-1 L 111 (109) [96], L/ W 9.0 (8.9) [7.8], S-2 L 91 (91) [80], L/ W 5.4 (6.0) [5.8], distance S-1-2, 22 (22) [14], L ratio S-1/2, 1.22 (1.2) [1.2]; I-L-6 L 149 (163) [137], HB 22 (22) [22], L/HB ratio 6.8 (7.4) [6.2]; L ratio I-L-5/6, 1.44 (1.45) [1.47].
Deutonymph (collected together with adults of A. damkoehleri at DC 78 84 and suspected to represent this species.): Integument dorsally striated; muscle attachments unsclerotized; glandularia maximum diameter 20; Cx-III W 192; Cx-I+II mL 57, lL 114; provisional genital field with two pairs of Ac, L/W 58/75; excretory pore smooth; Vgl-1 fused to Vgl-2 (Fig. 5A).
Palp: total L 154, dL: P-1, 15; P-2, 32; P-3, 39; P-4, 46; P-5, 22; L ratio P-2/P-4, 0.7.
I-L (Fig. 5B): I-L-5 dL 89, vL 63, dL/vL ratio 1.4, HB 30, dL/HB 3.0, S-1 L 52, L/ W 11.3, S-2 L 45, L/ W 7.3, distance S-1-2, 8.0, L ratio S-1/2, 1.16; I-L-6 L 69, HB 17, L/HB ratio 4.1; L ratio I-L-5/6, 1.3.
Remarks. The specimens examined from South Africa fit the descriptions of Atractides ugandensis (Lundblad, 1927) and A. duricorius (Walter & Bader, 1952), both species described from Eastern Africa and later synonymized with A. damkoehleri (see: K. O. Viets, 1964a). The measurements of the specimens examined lie within the variability range of A. damkoehleri given by K.O.Viets (1964a) for populations from Eastern Transvaal.
Atractides damkoehleri closely resembles two poorly known species from South Africa, A. sudafricanus K. Viets, 1956 and A. coriacellus K. Viets, 1956.
K. Viets (1956) described Atractides sudafricanus based on a single juvenile female specimen from Transvaal (without exact locality), providing only figures of the venter and palp, and without discussion of its similarity with other species. Later on, K.O. Viets (1964a) reported one female and one deutonymph of this species from Keurbooms River in the Eastern Cape and noted that additional material was needed to clarify the taxonomy of this species. He mentioned similarities in the shape of I-L-5 and -6 (S-1 obtusely truncate) with A. damkoehleri, but A. sudafricanus differs from the latter species in the shape of the coxae (Cx-IV medial margin angled, probably due to secondary sclerotization), the genital field (Ac in a weakly curved line) and palp (P-4 sword seta large, nearer to proximoventral hair). The measurements given in the original description of A. sudafricanus lie within the variability range of A. damkoehleri.
K.O. Viets (1964a) noted much variation (confirmed by our examination of the populations from different parts of South Africa) in many characters: position of P-4 sword seta (halfway between ventral hairs, approaching to disto- or proximoventral hair, see Figs. 4B,D), the shape of seta S-1 (regularly more or less apically obtusely truncated, but sometimes this character is not clear when the seta is slightly bowed, often as a result of mounting), the fusion of Vgl-3 (separate or fused with Cx-IV) and arrangement of Ac (from triangular to weakly curved). Furthermore, our examination of juvenile females of A. damkoehleri from the Mpumalanga province (material from Houtbosloop) shows much variation in the shape of Cx-IV, diameter of glandularia and fusion of Vgl-1 and -2 (Figs. 3 A-B) indicating that these characters are not suitable for species separation at a juvenile age.
Atractides coriacellus was described by K. Viets (1956) from the Western Cape province (Great Berg River), without discussion of its similarity with other species. Due to glandularia enlarged by secondary sclerotization, P-2 and -3 ventral margin straight, a smooth excretory pore and fused Vgl-1 and -2, A. coriacellus resembles A. damkoehleri from which it differs in a longer I-L-6 (I-L-5/6 L ratio 1.26) and slender (L/HB 6.3, calculated from K. Viets 1956) and seta S-1 apically slightly bowed and bluntly pointed. The other measurements given in the original description of Atractides coriacellus lie within the variability range of A. damkoehleri. Knowledge on the variability of additional specimens from the locus typicus is necessary before we can assess the taxonomic status of this species.
Distribution. Cameroon: K. Viets (1916), Liberia: Cook (1966), South Africa: Mpumalanga province (Eastern Transvaal): K. O. Viets (1964a), present study; Western Cape province: present study; East Africa: “ A. ugandensis ”, Lundblad (1952); “ A. duricorius ”, Walter & Bader (1952).
description: Published as part of Pešić, Vladimir, Smit, Harry & Gerecke, Reinhard, 2011, New records of water mites of the genus Atractides Koch, 1837 (Acari: Hydrachnidia, Hygrobatidae) from South Africa, with descriptions of five new species, pp. 1-54 in Zootaxa 2986 on pages 2-8, DOI: 10.5281/zenodo.200656