First description of collar receptors in Temnocephalidae (Platyhelminthes)

Abstract

Two species of Temnocephala (Platyhelminthes, Temnocephalida, Temnocephalidae), namely Temnocephala iheringi and Temnocephala haswelli, have collar receptors in the epidermis of the tentacles and general body surface, but not in the sucker region. These receptors were seen associated with clusters of 20–22 monociliary receptors. All collar receptors found in these temnocephalids bore six stereocilia. Other neoophoran platyhelminths have a constant number of eight stereocilia per collar receptor, the only exception being members of another family of Temnocephalida, the Didymorchidae, where collar receptor cells with five and six stereocilia have been recorded. Therefore, the presence of a lower number of stereocilia per collar receptor is likely to be an apomorphic trait of the Temnocephalida.

Ciliary receptors associated with the mouth and pharynx of Acoela (Acoelomorpha): a comparative ultrastructural study

“…Collar receptors, characterized by reinforced microvilli (stereocilia) encircling the sensory cilium, are commonly found in free‐living platyhelminths (Ehlers and Ehlers 1977; Rieger et al . 1991; Rohde and Watson 1993; 1995; Ponce de León and Volonterio 2003). In Prolecithophora, Proseriata, and Neorhabdocoela they project through epithelial cells of the body surface or pharynx, while in Macrostomida and Haplopharyngida, as in Acoela, they are situated between epithelial cells (Ehlers 1977).…”

“…An attribution of receptor cell types to certain body regions or glandular‐sensory organs has been made in a number of rhabdocoel turbellarians (e.g. MacRae 1967; Reuter 1975; Ponce de León and Volonterio 2003) and in parasitic flatworms (e.g. Lyons 1972; Rohde 1989; Bogéa and Caira 2001), but only in a few acoels (e.g.…”

Temnocephala (Platyhelminthes, Rhabdocoela) asociados a moluscos (Caenogastropoda, Ampullariidae): ecología y biogeografía

“…Si bien las especies de Temnocephala presentan un importante conocimiento de base sobre aspectos morfológicos, no existen estudios sobre las características y adaptaciones específicas a sus hábitos de vida. Se han realizado escasas contribuciones vinculadas a modelos de distribución en los hospedadores (Damborenea, 1998), densidad de comensales (Damborenea, 1996;de los Rios-Escalante et al, 2014;Zivano et al, 2020), ensambles en hospedadores (Damborenea et al 2006;Vega et al 2006), ultraestructura de la epidermis (Damborenea, 1992; Ponce de León y Volonterio, 2003;Damborenea & Cannon, 2001b;Seixas et al, 2015c), características particulares del sistema reproductor (Moretto y Durquet, 1977;Moretto, 2001), cariotipos (Ponce de León, 1988), estudios histológicos (Volonterio y Ponce de León, 2004), distribución geográfica (Martin et al, 2005) y sobre su biología alimentaria, nutrición y reservas (Jennings, 1968).…”