Rivellia alini Enderlein, 1937

Galinskaya, Tatiana V. & Ovtshinnikova, Olga G., 2015, Musculature of the male genitalia in Rivellia (Diptera: Platystomatidae), ZooKeys 545, pp. 149-158 : 152-154

Taxon classification Animalia Diptera Platystomatidae

Rivellia alini Enderlein, 1937

Material.

3 males: Russia, Primorsky Krai, Ussuri District, Kamenushka, 4 August 2013 (T.V. Galinskaya).

Description.

Lateral sclerite of hypandrium separated from hypandrium at right side; left sclerite completely fused with hypandrium. Subepandrial sclerite consisting of the elongate bifurcated medial part and elongate postero-lateral lobes. Lateral surstylus long, apically curved. Cerci paired, long, sclerotized, ventrally connected to subepandrial sclerite (Figure 1).

Platystomatidae have same set of muscles as in Ulidiidae , differing from them by the degree of development, shape, and their attachment sites (Figures 2, 3).

Muscles of the hypandrial complex: M1, M2, and M23. Strong, wide, and short phallapodeme retractors M1 connect the anterior part of hypandrium with grooves on the Y-shaped phallapodeme arms. Strong, wide, and long phallapodeme protractors M2 are attached to the distal half of the lateral surfaces of the unpaired phallapodeme lobe and to the inner surface of hypandrium at left and to the lateral sclerite at right side.

Ejaculator compressors M23 strong and long, surrounding ejaculator apodeme. Their contraction pumps semen into the phallus.

Tergosternal muscles. Tergosternal muscles M5 long, fan-shaped, connecting lateral parts of the epandrium anterior margin with lateral parts of anterior margin of hypandrium (in contrast to Ulidiidae , in which these muscles are attached to the distal margin of the hypandrium). These muscles draw hypandrium to epandrium. During copulation, epandrium clasps female’s ovipositor while the hypandrium is retracted into the male’s abdomen by contraction of these muscles.

Muscles of the epandrial complex: M3, M4, M7, and M25.

Subepandrial sclerite adductors M3 strong, connecting the inner surface of the epandrium (occupying a considerable part of it) to the inner surface of anterior part of the subepandrial sclerite as a wide bundle.

Adductors of surstyli M4 short, fine, poorly visible, extending from the middle of long posterolateral lobe of the subepandrial sclerite (medial surstyli) to the middle of lateral part of at inner surface of the (lateral) surstylus.

Cercus retractors M7 short, fine, extending from the inner surface of the basal part of the epandrium to the basal cercal lobes.

The long and fine poorly visible retractors of anal integument M25 connect the median part of medial surstyli with the basal part of the rectum.

Pregenital muscles: M182 and M19. The unpaired adductor of the hypandrium M182 extends from the distal part of syntergosternite 8 to the left hypandrial arm. The strong fan-shaped unpaired epandrial retractor M19 obliquely extends from the distal part of syntergosternite 8 to the left part of the basal margin of the epandrium.