On a new Temnocephala (Platyhelminthes) from Southern Patagonia (Chile, Argentina), with a redescription of T. chilensis and some systematic and biogeographical insights.

To date, only one species of Temnocephala is known from Chile, Temnocephala chilensis, and three from southern Argentina (Patagonia), namely T. chilensis, Temnocephala dionii, and Temnocephala mexicana. Here we describe a new species of Temnocephala and provide an updated description of T.

A new species of Temnocephala (Platyhelminthes) with an unusual pharynx, including an amendment of the diagnosis of the genus.

Three species of Temnocephala have been reported on Aegla from Uruguay: Temnocephala axenos, Temnocephala mertoni and Temnocephala talicei. As part of a systematic review of the Uruguayan species of Temnocephala, a fourth species was found on Aegla platensis and Aegla uruguayana. This species, new for the genus, has the following diagnostic characters: Large temnocephalan; slightly curved penial stylet (225 µm in length) with a symmetrical introvert (27 long by 18 µm in diameter) that has at least 44 spine-like projections, each bearing 7 rows of internal spines; a seminal vesicle that opens sub-polarly into the contractile vesicle; a muscular vagina with a strong asymmetrical sphincter; preequatorial nephridiopores close to the internal borders of the elongate-oval excretory syncytia; a large pharynx with anterior and posterior sphincters of about the same diameter and a narrow pharyngeal lumen with nearly uniform width.

Ultrastructural description of the spermatogenesis and spermatozoa in Phaenocora unipunctata (Platyhelminthes, Neotyphloplanida).

Ultrastructural studies of spermiogenesis and sperm morphology have found many characters that are likely to provide clues to the phylogeny of the Platyhelminthes. However, the lack of information on many free-living groups has been a limiting factor. There is a single description of the spermatogenesis and spermatozoa in a Phaenocora species, namely P.

Description of a New Temnocephala Species (Platyhelminthes) from the Southern Neotropical Region.

The genus Temnocephala is endemic to the Neotropical region. Temnocephala mexicana and Temnocephala chilensis are the only 2 temnocephalans whose known distribution ranges extend to the south beyond Parallel 40°S. No Temnocephala species has ever been recorded from the extensive area between Parallel 43°S and the southern end of the South American continent, which makes the study of the southern limit of the distribution of the genus a topic of great interest.

A new Paravortex (Platyhelminthes, Dalyellioida) endoparasite of Mesodesma mactroides (Bivalvia, Mesodesmatidae) from Uruguay.

Many species of turbellarians (Platyhelminthes) are known to live associated with other organisms, especially invertebrates, as commensals or parasites. The family Graffillidae (Rhabdocoela) includes two genera that parasitize mollusks, Graffílla and Paravortex. Within the latter genus, six species were described as associated with mollusks.

Description of Dendrorchis retrobiloba n. sp. (Digenea: Gorgoderidae) from Astyanax fasciatus (Teleostei: Characidae) from Southern Uruguay, with an emended diagnosis of the genus Dendrorchis.

To date, the monospecific Dendrorchis is represented by D. neivai, reported from Brazil and parasitizing Brycon lundi. Dendrorchis retrobiloba n.

The first ultrastructural description of the Haswell cells in Temnocephalidae (Platyhelminthes, Temnocephalida), with insights into their function.

This paper provides the first description of the Haswell cells at the ultrastructural level, as well as giving an insight into their function. Two species of Temnocephalidae were studied, Temnocephala iheringi and T. haswelli.