Stenostomum cryptops Nuttycombe & Waters, 1935

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 : 44

Stenostomum cryptops Nuttycombe & Waters, 1935

( Fig. 1E )

Description: Isolated specimens, 0.4–0.5 mm long. Chains of up to six zooids (3 mm long). Anterior end blunt. Body constriction behind the ciliated pits. Tapering posterior end. Large, deep dorso-lateral ciliated pits. Uniformly ciliated epithelium. Scarce semirigid sensory cilia. Rhabdites uniformly distributed. Colour in life white.

Brain large and elongated. Anterior brain lobes divided into small independent masses (‘metamerics’). A pair of light-refracting bodies formed of small spheres included in a vesicle (type 2) associated with the anterior brain lobes.

U-shaped oral pore. Short muscular pharynx. Small pharyngeal glands (type a) in the anterior region, elongated glands (type b) in the posterior region. Welldeveloped pharyngeal sphincter. An intestinal caecum with granulose epithelium, dorsal to the pharynx. High intestinal epithelium. Excretophores laterally placed. Nephridiopore terminal or subterminal.

Distribution: Georgia, USA ( Nuttycombe & Waters, 1935; Kolasa, 1991); São Paulo, Brazil ( Marcus, 1945b).

Discussion: At variance with the single pair of lightrefracting bodies described by Marcus (1945b), Nuttycombe & Waters (1935, 1938) describe a second pair, associated with the posterior lobes and larger than the first pair.

Figures

Figure 1. A, Stenostomum amphotum. B, S. arevaloi. C, S. bicaudatum. D, S. ciliatum. E, S. cryptops. Scale bars = 200 Mm.