Arcoppia (Wallworkoppia) directa, Mahunka & Mahunka-Papp, 2007

Mahunka, S. & Mahunka-Papp, L., 2007, Taxonomical And Faunistical Studies On Oribatids Collected In Kenya (Acari: Oribatida) I., Acta Zoologica Academiae Scientiarum Hungaricae 53 (1), pp. 51-74 : 64-66

Arcoppia (Wallworkoppia) directa sp. n.

( Figs 24–27 )

Diagnosis – Rostrum tripartite, median apex smaller than the lateral ones. Typical prodorsal structure, but the median horseshoe-like costula short, straight or waved medially. Sensillus with 5–6 gradually shortened branch in one side, its peduncle slightly dilated. Two pairs of maculae in the interbothridial region, tubercles absent. No essential difference – except the short setae ta – in the lenght of notogastral setae, setae ti and te located along a transverse line. Six pairs of genital setae arranged nearly in two rows. Inner costula along the discidium well developed. Legs IV removed backwards.

Material examined: Holotype: Kenya, Nairobi, 19.11.2004. Leg. CS . CSUZDI (Afr. 974) . 11 paratype from the same sample. Holotype (1693-HO-2005) and 9 paratypes (1693-PO-2005): HNHM , 2 paratypes: MHNG .

Measurements: Length of body: 275–302 µm, width of body: 132–143 µm.

Prodorsum: Median rostral apex clearly shorter than the lateral ones, among them deep incisure present ( Fig. 25 ). Shape of the prodorsal costulae atypical, the median, horseshoe-shaped one without longitudinal parts ( Fig. 24 ). S-shaped lateral costulae distinct. Interlamellar region with two pairs of maculae present, behind them a transversal line frames the posterobothridial region, which bears no tubercles or other structures. All prodorsal setae short, lamellar and exobothridial ones shorter than the two other pairs. Sensillus pectinate, without a distinct head, bearing 5–6 distally gradually shortened branches.

Notogaster: Narrow and elongate. Dorsosejugal suture slightly convex. Ten pairs of notogastral setae present, setae c 2 short and simple, all others much longer and finely roughened or sometimes ciliate. No essential difference among them, only lp, h 2 and h 3, slightly longer than the others.

Lateral part of podosoma: S-shaped lateral costula well sclerotised, reaching to the acetabula of leg I, its basal part continuing as line of granules towardís the to bothridium. Exobothridial region also well granulated by large granules. Acetabulum of leg IV removed posteriorly from acetabulum III ( Fig. 27 ).

Ventral parts ( Fig. 26 ): Epimeral borders and apodemes mostly well developed and sclerotised. On the sejugal borders a pair of triangular tuberles observable. A weak polygonal pattern visible on epimeres III and IV. All epimeral setae simple and short, setae 3c the longest. Setae 1c arising on the ridge framing the epimer I. Anal plate with a longitudinal crest, directed somewhat obliquely. Position of genital aggenital and adanal setae normal, ad 1 arising postanally.

Remarks – The new species is well characterised by the form of median rostral apex, the short longitudinal part of the median prodorsal costula, the pectinate sensillus, the absence of the structure in the posterobothridial region, the postion of the notogastral setae, and by the great distance between legs III and IV, as well as the position of adanal setae (see MAHUNKA 1999). On the basis of these characters it stands nearest to Arcoppia (Wallworkoppia) machadoi (BALOGH, 1958) , however, the median rostral apex in the new species is much smaller, setae la and lm arising in a transversal line (setae la clearly in front of the lm along the machadoi ) and no tubercle-like structure in the posterobothridial region in the new species (2 pairs in machadoi ).

Etymology – Named after the short, but nearly straight transverse costula on the prodorsum.

Figures

Figs 24–27. Arcoppia (Wallworkoppia) directa sp. n. – 24 = body in dorsal view, 25 = rostrum, 26 = body in ventral view, 27 = prodorsum in lateral view