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You are here:   OldClasses > 2012 > Pseudoceros prudhoei | Carolina Marques



Pseudoceros prudhoei


Carolina Marques (2012)



Fact Sheet



Physical Description


Life History & Behaviour

Anatomy & Physiology

Evolution & Systematics

Biogeographic Distribution

Conservation & Threats

References & Links

Anatomy & Physiology

Body Wall: Turbellarians have a monolayered epidermis that holds numerous cilia and lack cuticle (Ruppert et al, 2004). They usually have diverse glands that can secrete adhesive substances, mucus and even rod-shaped structures called rhabdoids (Liana et al., 2011). From cross sections of the P. pudhoei’s body it is possible to observe a higher concentration of cilia on the ventral surface than on the dorsal one, which can be explained by the fact that these cilia are related to locomotion over substrates. We can also identify a basal lamina and a well developed parenchyma, which consists of connective tissue between the body wall and the gut (Fig.5.1 A, B e C).

Figure 5.1: Micrographies of the body wall of P. prudhoei. A: dorsal epidermis. B: ventral epidermis.
C: parenchyma.

Musculature and Locomotion: P. prudhoei is a large turbellarian and uses not only cilia but also body movements for locomotion. For that reason, it has a well developed musculature, with multiple layers of circular, longitudinal and diagonal fibers forming a complex arrangement (Ruppert et al, 2004) (Fig.5.2).

Figure 5.2: Locomotion of P. prudhoei. The big arrow indicates
the direction of the movement and the small arrows
incate the undulations of the body margins.

Nervous and Sensory System: Polyclads have a diffuse, netlike nervous system with a ringlike brain and longitudinal nerve cords that join the nerve nets (Fig. 5.3) (Ruppert et al, 2004). Pseudoceros have pigment-cup ocelli organized in clusters over the brain (cerebral eyes) and in the tentacles (pseudotentacular eyes) that detect the presence and absence of light (Fig. 5.4) (Sopott-Ehlers,1991).

Figure 5.3: Netlike nervous system of P. prudhoei. Adapted from Ruppert et al (2004).

Figure 5.4: Cerebral and pseudotentacular eyes of P. prudhoei.
Adapted from  Newman and Cannon (1998) and Ruppert et al (2004).

Digestive System: P.prudhoei has a long protrusible plicate pharynx used for feeding and its intestine is blind (has only one aperture for the exterior, the mouth) (Fig.5.5 A and B). Also, the gut is highly branched and these lateral cecae form a gastrovascular system that helps distributing nutrients for the margins of the body (Ruppert et al, 2004).

Figure 5.5 A and B: Ventral surface showing the position of the pharynx,
male and female pores in P. prudhoei. Adapted from  Newman and Cannon (1998).



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