Marine Rhabdocoela (Platyhelminthes, Rhabditophora) from Uruguay, with the description of eight new species and two new genera

Abstract

An overview of the marine rhabdocoel fauna of Uruguay is given. Eight species, new to science, are described and discussed. Two of these, Acirrostylus poncedeleoni n.g. n.sp. and Polliculus cochlearis n.g. n.sp. could not be placed in any existing genera. A. poncedeleoni n.g. n.sp. can be recognized from other Cicerinidae Meixner, 1928 by the fact that there is only one ovovitellarium and by the lack of a cirrus in the male atrium. P. cochlearis n.g. n.sp. is characterized by the fact that there is only one testis and vas deferens, a unique situation within the Dalyelliidae Graff, 1905. Apart from these two species, six other new species are described: Cheliplana triductibus n.sp. and C. uruguayensis n.sp. (Karkinorhynchidae Meixner, 1928), Carcharodorhynchus viridis n.sp. (Schizorhynchidae Graff, 1905), Baicalellia forcipifera n.sp. (Provorticidae Beklemischew, 1928) and Vauclusia multistriata n.sp. and Coronhelmis mimosa n.sp. (Promesostomidae Den Hartog, 1964). All these species can be recognized from their congeners by the detailed structure of the genital organs in general, and the copulatory organ in particular. For four known species of Dalytyphloplanida Willems, 2006 new data are given: Ceratopera axi (Riedl, 1954) Den Hartog, 1964 (Trigonostomidae Graff, 1905), Lurus evelinae Marcus, 1950 (Luridae Sterrer & Rieger, 1990), Byrsophlebs caligulachaena (Ehlers & Ehlers, 1981) Karling, 1985 (Byrsophlebidae Graff, 1905) and Oneppus lacus Marcus, 1954 (Placorhynchidae Meixner, 1938). The occurrence of one new species of Polycystididae Graff, 1905 and the possible occurrence of Cheliplana firmata Brunet, 1968 and Proschizorhynchus atopus Marcus, 1950 are also mentioned.

Molecular phylogeny of Kalyptorhynchia (Rhabdocoela, Platyhelminthes) inferred from ribosomal sequence data

“…Because of its aberrant morphology, Acirrostylus cannot be placed at the moment (see Van Steenkiste et al . ). 4.The schizorhynch taxon Karkinorhynchidae is polyphyletic.…”

“…We therefore propose to split Cicerinidae into two subtaxa: Acrumeninae (with Acrumena and Ethmorhynchus ) and Cicerininae (with Cicerina Giard, 1904, Paracicerina Meixner, 1928, Ptyalorhynchus Ax, 1951 and Xenocicerina ). Two taxa were not included in our analysis: Didiadema Brunet, and Acirrostylus Van Steenkiste et al., . Didiadema shares a number of features with the representatives of Acrumeninae, especially the lack of sclerotised spermatic ducts is typical of this taxon (see Brunet , ).…”

Molecular phylogeny of neodalyellid flatworms (Rhabdocoela), including three new species from British Columbia

“…Unconnected testes may represent multiple independent secondary losses of the anastomosing commissure, although it is possible that this character shows plasticity during the animal's development. This seems to be the case in the rhabdocoel Lurus evelinae, whose paired testes coalesce in some specimens and not in others (Van Steenkiste et al., ).…”

“…Baicalellia rectis, Pogaina japonica; Ax, 2008). Here "copulatory bursa" and "seminal bursa" are used sensu Van Steenkiste et al (2008) in an attempt to standardize the terminology. The copulatory bursa is a blind, usually muscular sack protruding from the common genital atrium, that likely STEPHENSON ET AL.…”

Cicerina debrae n. sp. (Platyhelminthes: Kalyptorhynchia, Cicerinidae) from the Southern Atlantic Coast, USA

“…The traditional phylogenetic placement of the family Cicerinidae within the Eukalyptorhynchia, already cast in doubt (see Van Steenkiste et al 2008), is also not supported by molecular data which show the majority of cicerinid species forming a clade at the base of the Schizorhynchia (Tessens et al submitted). Our own results based on 18S sequence from this new species agree with theirs (Smith et al 2013).…”