Thoracophoracarus, K. Viets, 1914

Gerecke, Reinhard, 2009, Revisional studies on Thoracophoracarus K. Viets, 1914 (Arachnida, Acari, Hydrachnidia, Arrenuridae), Zoosystema 31 (1), pp. 127-145 : 131-133

Thoracophoracarus (s.s.) kuehnei K. Viets, 1916 ( Fig. 3 )

Thoracophoracarus kuehnei K. Viets, 1916: 369 , fig. 46a-c.

TYPE MATERIAL. — Holotype: Cameroon, river Mbome near village Mpobo (15 m large, 1.5 m deep), from stones, 21.VI.1913, Damköhler leg., 1872, ♂ ( SMF 47459).

Paratypes: Cameroon, river Njong river upstr. Njong cascades (2 ½ hours from railway km 180), on the way to village Lolo, near village Makomól (130 m large, 10 m deep, blackwater without vegetation), from mud with leaf litter, 28.XII.1914, Damköhler leg., 3150, 2 ♀♀ ( SMF 47466) ; “ allotypus ”, 3 ♂♂ ( SMF 47465, 55028 , 55029 ) .

DESCRIPTION

Idiosoma egg-shaped, caudally truncated ( Fig. 3A, B, D ). Anteriorly with a pair of small humps associated with the antenniform setae. Legs as described for T. arrhenuroides . Genital field and caudal idiosoma with strong sexual dimorphism. In both sexes acetabular fields slender and extending to the dorsal idiosoma, with about 40 acetabula on each side. Palp setation similar to T. arrhenuroides , but P-1 with a dorsal seta ( Fig. 3C ). P-2 subrectangular, P-4 dorsal and ventral margins distally divergent, ventrodistal extension pointed, slightly bent dorsally.

Male ( Fig. 3 A-C): in lateral view, posterior third of idiosoma abruptly flattened and forming a groove anteriorly delimited by an open, in dorsal view, inversely V-shaped transverse step. Posterior margin with a deep indentation, proximally a little wider than distally, at its deepest point the caudally-directed anal pore. Gonopore located immediately anterior to this indentation, at the posterior margin of the genital field and directed ventrocaudally.Acetabular fields nearly straight, perpendicular to the longitudinal body axis. Measurements: idiosoma L/W

610/400, Cx-4 W 470; acetabular field L/W 35/160; palp L/H P-1 25/25, P-2 55/40, P-3 33/40, P-4 63/40, P-5 33/13.

Female ( Fig. 3D ): in lateral view, idiosoma in its posterior third gradually flattened; posterior margin in dorsal view slightly concave, with the anal pore directed caudally. Gonopore rather large, directed ventrocaudally, located at posterior edge of acetabular fields; acetabular fields not well defined, medially reaching the gonopore in an obtuse angle, laterally bent as narrow strip perpendicular to the main body axis. Measurements: idiosoma L/W 585-590/485-490, Cx-4 W 485-490; gonopore 100/112; palp L/H P-1 25/25, P-2 54/37, P-3 29/37, P-4 60/38, P-5 29/10.

REMARKS

Both sexes of T. kuehnei differ from T. arrhenuroides in the position of the gonopore which is shifted posteriorly (further from Cx-4 than from posterior idiosoma margin) and directed ventrocaudally, and in the presence of a seta on P-1. In addition, males of T. kuehnei are distinguished by the deep indentation of posterior idiosoma and the absence of a finger-like dorsocaudal extension.

Figures

FIG. 3. — Thoracophoracarus kuehnei K. Viets, 1916: A-C, paratype ♂ (SMF 55029); A, ventral idiosoma; B, dorsal idiosoma; C, palp; D, paratype ♀ (SMF 47466), ventral idiosoma. Scale bars: 100 μm.