Anokkostenostomum ventronephrium (Nuttycombe, 1932) Noreña & Damborenea & Brusa, 2005

Noreña, Carolina, Damborenea, Cristina & Brusa, Francisco, 2005, A taxonomic revision of South American species of the genus Stenostomum O. Schmidt (Platyhelminthes: Catenulida) based on morphological characters, Zoological Journal of the Linnean Society 144 (1), pp. 37-58 : 54

Anokkostenostomum ventronephrium (Nuttycombe, 1932) comb. nov.

( Fig. 5E )

Stenostomum ventronephrium Nuttycombe, 1932

Description: Single individuals, 0.5–0.8 mm long. Three-zooid chains, 2 mm long. Anterior end spatulate. Long lateral ciliated pits. Posterior end without an intestine-lacking region, ending bluntly, no tail. Body uniformly covered with cilia. Semi-rigid cilia, more abundant at both body ends. With epidermal rhabdites. With groups of 10–15 conspicuous rhabdites at the anterior body end. These rhabdites are produced at glands situated latero-dorsally to the pharynx, which have four tracts (two dorsal and two lateral) through which the rhabdites migrate. Whitish, reddish or colourless in life. Brain ganglia with well-developed transverse commissure. No light-refracting bodies.

Oral pore circular, surrounded by muscles. Long, wide, muscular and densely ciliated pharynx. Granular pharyngeal glands (type b), placed mainly ventrally and opening at mouth level. Dorsal wall of the intestine overlying the pharynx. No excretophores. The protonephridium runs dorsal to the pharynx, loops towards the left and continues ventrally or ventro-laterally to the intestine. Nephridiopore subterminal.

Distribution: Virginia, USA ( Nuttycombe, 1932b; Kolasa, 1991); Tieté River, São Paulo, Brazil ( Marcus, 1945a); Italy ( Kolasa, 1983).

Discussion: Differences between the South and North American specimens are: absence of tail and presence of rhabdite-forming glands in the South American specimens ( Nuttycombe, 1932b; Marcus, 1945a).

Figures

Figure 5. A, Anokkostenostomum pegephilum. B, A. pseudoacetabulum. C, A. saliens. D, A. tuberculosum. E, A. ventronephrium. Scale bars = 100 Mm.