Thoracophoracarus fluviatilis, Smit, 2012

Smit, H., 2012, New records of the water mite family Arrenuridae from the Afrotropical region, with the description of 11 new species and two new subspecies (Acari: Hydrachnidia), Zootaxa 3187, pp. 1-31 : 28-29

Thoracophoracarus fluviatilis n. sp.

( Figs. 76–78)

Material examined. Holotype female, Wolwekloof River at Tweede Tol, Limietberg NR, Western Cape Province, South Africa, 33° 34.115 S 19° 08.255 E, 3.xi.2004 ( BMSA) . Paratype: female, same data as holotype ( RMNH) .

Diagnosis. Glandularia D2 and D3 next to each other; genital field long, narrow and straight.

Description. Female: Idiosoma 622 (626) long and 500 (502) wide, yellowish. Glandularia D1 close to A2, D2 medial of D3. Most idiosoma pores elongate, but other shapes, e.g. more triangular, are present as well. Anterior idiosoma margin concave, glandularia A1 on tubercles. Posterior idiosoma margin somewhat undulating, but straight in paratype. First coxae extending beyond anterior idiosoma margin. Suture lines of coxae indistinct, lateral margin of coxal field with short, heavy setae. Glandularia Cxgl-4 close to posterior margin of fourth coxae. Gonopore 96 long and 114 wide. Genital plates straight, narrow and extending to lateral idiosoma margin. Lengths of PI-PV: 29, 60, 40, 68, 28; PII anteroventrally with two pinnate setae, more dorsally one more medial seta. Lengths of I-leg-4-6: 76, 78, 78. Lengths of IV-leg-4-6: 113, 118, 98. Legs with many swimming setae, I-leg-5 also with one swimming setae.

Male: Unknown.

Etymology. Named for its occurrence in a river.

Remarks. Females of the genus Arrenurus are notoriously difficult to identify, and new species should not be described based on females only. Within the genus Thoracophoracarus females are easier to identify. The new species is unique in the configuration of the dorsal glandularia, as D2 is medial instead of posterior of D3. Only in T. kuehnei K. Viets, 1916 are these glandularia located next to each other, at least in the male. The female of this species has, however, a reversed wing-shaped genital field ( Gerecke 2009).