Stenostomum matarazzoi Marcus, 1949

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 : 47

Stenostomum matarazzoi Marcus, 1949

( Fig. 2E )

Description: Solitary specimens 1–1.5 mm long. Chains of four zooids, 2.5 mm long. Chains of six zooids, 3 mm long. Anterior end blunt. Posterior end with an intestine-lacking region. Apical ciliated pits. Constriction of the body at the level of the mouth. Live specimens are vermilion red, owing to the secretions of the glandular epidermal cells. These secretions appear as irregular spots on the surface. Body surface homogeneously covered by cilia that are longer on the mid-ventral line. Semi-rigid sensory cilia, more abundant at both body ends. The rhabdites are placed in the cells among the glands. The rhabdites and the glands are absent on the mid-ventral line and around the ciliated pits.

Anterior brain lobes deeply dentate. Posterior brain lobes with developed internal lobe (trilobate brain after Marcus, 1945a). A pair of light-refracting bodies formed by numerous spheres, type 1, associated with the posterior brain lobes.

Oral pore triangular. Short bag-like pharynx, a constriction dividing it into two parts: a rostral one with thick epithelium, short cilia and cyanophilic glands; and a caudal one with long cilia and no glands. Circular musculature present. Intestine with Minot’s club-shaped cells, but without excretophores. Nephridiopore subterminal, ventral.

Distribution: Periodic pools near the Pirajussara River (tributary to the Pinheiros River), São Paulo, Brazil ( Marcus, 1949).

Figures

Figure 2. A, Stenostomum glandulosum. B, S. grande. C, S. hemisphericum. D, S. leucops. E, S. matarazzoi. Scale bars = 200 Mm.