Nomimoscolex semenasae n. sp. (Proteocephalidea: Monticelliidae), a cestode parasite of Diplomystes viedmensis (Pisces: Siluriformes) from the Patagonian region of Argentina

Abstract

Nomimoscolex semenasae n. sp. is described from the primitive fish Diplomystes viedmensis (Siluriformes) from the Patagonian region of Argentina. The new species is placed in Nomimoscolex because of the cortical position of the vitelline follicles, medullary position of the testes, ovary and uterus, and having a scolex with four uniloculate suckers. N. semenasae differs from all other species in the genus by the following combination of characters: (1.apical organ absent; (2). strobila acraspedote; (3). vagina anterior or posterior to cirrus-sac and lacking a sphincter; (4). testes in one irregular layer and in two fields connected anteriorly; (5). uterine stem cortical in immature proglottides, growing from cortical stem into medullary region in mature proglottides; (6). long uteroduct; and (7). presence of spiniform microtriches on all regions of the scolex, proliferation zone and immature proglottis. This is the first record of a proteocephalidean tapeworm in D. viedmensis and in the family Diplomystidae.

Transmission electron microscopy of the scolex and neck microtriches of Silurotaenia siluri (Batsch, 1786) (Cestoda: Proteocephalidea)

“…The knowledge of the distribution of different types of microtriches might be of some taxonomic value and can be useful in systematic and phylogenetic studies (Gil de Pertierra 2005). Currently more SEM than TEM information of microtriches is available, and only a few SEM and TEM studies have been carried out in the Proteocephalidea (Threadgold 1965;Thompson et al 1980;Scholz et al 1999;Ž d'a´rska´and Nebesa´rˇova´1999;Gil de Pertierra 2002, 2004, 2005.…”

The taxonomic status of Spatulifer cf. maringaensis Pavanelli & Rego, 1989 (Eucestoda: Proteocephalidea) from Sorubim lima (Bloch & Schneider) (Pisces: Siluriformes), and the use of the microthrix pattern in the discrimination of Spatulifer spp.

“…To date, only a few studies on proteocephalidean cestodes include the microthrix pattern for characterising and distinguishing species (Gil de Pertierra, 2002, 2004, 2005de Chambrier et al, 2005. In the present work, the microthrix pattern provides additional evidence that Spatulifer cf.…”

Nomimoscolex pertierrae n. sp. (Eucestoda: Proteocephalidea), a parasite of Pseudoplatystoma corruscans (Siluriformes: Pimelodidae) in Brazil and redescription of N. sudobim Woodland, 1935, a parasite of P. fasciatum

“…Nomimoscolex is a polyphyletic genus, as demonstrated by Zehnder et al (2000) and by several other authors (Freze, 1965;de Chambrier & Vaucher, 1992, 1997de Chambrier et al, 2004a;Gil de Pertierra 2002, 2003Brooks, 1995;Pavanelli & Takemoto, 1995). Woodland (1935a) also suggested that the five described species are ''more or less considerably different and may, later on, have to be referred to different genera''.…”

“…However, microtriches have been relatively neglected in the Proteocephalidea. Recently, Gil de Pertierra (2002, 2005 and de Chambrier et al (2005) characterised microtriches in several proteocephalidean taxa. The clear differences in the shape of the microtriches of the congeners Nomimoscolex pertierrae n. sp.…”

“…sudobim Woodland, 1935;N. suspectus Zehnder, de Chambrier, Vaucher & Mariaux, 2000;and N. touzeti de Chambrier & Vaucher, 1992(See Woodland 1933, 1934a,b, 1935aBrooks & Deardorff, 1980;Rego, 1989;Rego & Pavanelli, 1990;de Chambrier & Vaucher, 1992;Gil de Pertierra 1995, 2002, 2003Pavanelli & Takemoto 1995;Zehnder et al, 2000).…”