Steganacarus (Rhacaplacarus) quaternarius, Niedbała, Wojciech & Starý, Josef, 2014

Niedbała, Wojciech & Starý, Josef, 2014, New and little known species of ptyctimous mites (Acari, Oribatida) from Cameroon, Zootaxa 3889 (1), pp. 31-57 : 44

Steganacarus (Rhacaplacarus) quaternarius sp. nov.

( Fig. 7A–H )

Measurements of holotype. Prodorsum: length 278, height 111, width 207; prodorsal setae: sensillus 96, interlamellar (in) 139, lamellar (le) 43, rostral (ro) 56, exobothridial (ex) 15; notogaster: length 555, height 404, width 353; notogastral setae: c 1 126, h 1 144, ps 1 109; genitoaggenital plate 121×109, anoadanal plate 215×111.

Description. Species with neotrichy of adanal setae. Colour light brown. Integument finely pitted.

Prodorsum with sigillar fields distinct, median longer than laterals. Lateral carinae with some traces visible of distal part. Sensilli rather long, with narrow stalk and slightly fusiform head covered with very small spines. Interlamellar setae long, erect, rigid, covered sparsely with small spines in distal half, similar to notogastral setae; lamellar and rostral setae short, spiniform, and rough.

Notogaster with notogastral setae of medium length (c 1/ c 1- d 1=1.0), rather pointed distally, covered with small spines on their distal half. Notogastral setae c 1 and c 3 slightly remote from anterior notogastral margin, setae c2 considerably further from margin. Vestigial setae f 1 situated anteriorly of setae h1. Two pairs of lyrifissures, ia and im, present.

Ventral region. Setae h of mentum longer than distance between their insertion points. Genitoaggenital plates with nine pairs of setae on right plate or 10 pairs on left plate with formula: 6(4+2): 3 or 7(5+2): 3. Anoadanal plates each with seven setae; three anal setae at the paraxial row and four adanal setae remote from paraxial border, adanal setae ad 1 and ad 2 the longest.

Legs. Formulae of leg setae and solenidia of complete type. Setae d on femora I positioned at distal end of article.

Material examined. Holotype is deposited at DATE from the locus typicus: South–West Province, Mt. Koup Ecological Reserve, Mt. Koup at Nyasoso, 19–21. V. 2006, about 6 km N of Loum, latitude 04°49'09.18" N, longitude 09°42'27.18" E, altitude 1550 m, submontane foggy forest, litter and soil sifting sample, leg V. Grebennikov.

Etymology. The specific name quaternarius comes from Latin for “consisting of four, arranged in four” alluding to the four pairs of adanal setae.

Comparison. The new species is well characterisable by the presence of four pairs of adanal setae remote from paraxial border of plates. Other Afrotropical Rhacaplacarus species have two pairs of these setae. Some Neotropical species of subgenus Rhacaplacarus with presence also of four pairs of adanal setae remote from paraxial border of plates are morphologically completely different. The most similar Afrotropical Steganacarus (Rhacaplacarus) spinatus Niedbała, 2001 by the length of interlamellar, lamellar and notogastral setae is distinguishable by the presence of flagellate sensilli (versus slightly fusiform sensilli, obtuse distally) and notogastral setae obtuse distally (versus rather pointed distally).

Figures

FIGURE 7 A – H. Steganacarus (Rhacaplacarus) quaternarius sp. nov. (holotype). A, prodorsum, dorsal view; B, prodorsum, lateral view; C, opisthosoma, lateral view; D, mentum of subcapitulum; E, genitoaggenital plates; F, left anoadanal plate; G, trochanter and femur of leg I; H, tibia IV.