Explore the vast range of titles available.

The type material of Polylekithum ictaluri, P. halli, and Maculifer chandleri was examined from the United States National Parasite Museum, and we determined that the material was conspecific, making P. halli and M. chandleri junior subjective synonyms of P. ictaluri. Polylekithum catahoulensis sp. nov. was described from material collected from catfishes at the Catahoula Wildlife Refuge, LaSalle Parish, Louisiana, USA, and compared with P. ictaluri collected from catfishes in Reelfoot Lake, Obion County, Tennessee, USA, and the Pearl River, Hancock County, Mississippi, USA. Polylekithum catahoulensis had smaller eggs (77–88 μm long by 51–63 μm wide vs. 94–108 μm by 52–76 μm) and a longer forebody (35–41% of overall body length vs. 29–34%). Comparison of more than 2,400 bp long fragments of nuclear ribosomal DNA (complete ITS and partial 28S regions) strongly supported the status of P. catahoulensis as a new species. Molecular phylogenetic analysis of 28S rDNA gene sequences from Polylekithum as well as representative species from Allocreadiidae, Atractotrematidae, Brachycoeliidae, Callodistomidae, Dicrocoeliidae, Encyclometridae, Gorgoderidae, Haploporidae, Opecoelidae, Plagiorchiidae, and Telorchiidae rooted by Monorchiidae and Lissorchiidae demonstrated that of the families tested, Polylekithum was most closely related to Encyclometridae as a gorgoderoid and not to Allocreadiidae as previously reported. Morphological features of three South American allocreadiids, Allocreadium patagonicum, P. percai, and A. pichi were inconsistent with generic diagnoses of Allocreadium and Polylekithum, so we suggested they belonged in a single unnamed genus similar to Creptotrema. Polylekithum catlai from India was assessed from the description and failed to conform to the generic diagnosis of Polylekithum. Morphology of Caudouterina suggested a close relationship with Polylekithum and not Allocreadiidae.

Parabrachycoelium longicaecum n. gen., n. sp. (Digenea: Brachycoeliidae) is described from the intestine of a plethodontid salamander Chiropterotriton sp. Hosts were collected in bromeliads at the cloud forest of Tlaquilpa, Veracruz, Mexico. Members of the Brachycoeliidae Looss, 1899 (sensu Yamaguti, 1971) are characterized by having a spined tegument; ceca usually short, not passing level of gonads, but longer in some species; gonads posterior to, or in region of, acetabulum, with ovary anterior to testes; a well developed cirrus pouch containing a bipartite seminal vesicle; and uterus occupying entire hind-body posterior to testes. However, this combination of morphological traits prevents the inclusion of the new taxon in any of the genera in that family; a new genus was, therefore, erected to accommodate the new species. The new taxon is readily distinguished from members belonging to Brachycoelium Dujardin, 1845, Mesocoelium Odhner, 1910, and Tremiorchis Mehra and Negi, 1925, by having long ceca extending into the posterior third of the body, slightly surpassing the testes, and vitellaria extending along the body. The new species morphologically resembles Caudouterina rhyacotritoniMartin, 1966, a digenean parasitizing a plethodontid salamander; however, the latter species lacks spines in the tegument and is actually placed within the Allocreadiidae. To demonstrate further the phylogenetic position of the new taxon, we sequenced the D1–D3 regions of 28S rRNA gene and conducted a phylogenetic analysis of available sequences for the order to which brachycoeliids belong (Plagiorchiida). Sequence divergence of the partial 28S rRNA gene confirms its distinction from the aforementioned brachycoeliids, and the phylogenetic position within the Plagiorchiida places the new species as closely related to a clade formed by Brachycoelium + Mesocoelium. Divergence levels and phylogenetic position within the Plagiorchiida verifies the validity of the new genus and its inclusion in Brachycoeliidae.