Revisão taxonômica da família Ceramonematidae (Plectida, Nematoda).

Abstract

The family Ceramonematidae includes exclusively marine nematodes, found in coarse sands of shallow water and fine sediments such as silt and clay. Most works on Ceramonematidae are ecological and few are taxonomic. A significant number of species have sparse descriptions and simple sketch drawings (especially older works), which make it difficult to identify the group. This study aimed to taxonomically review the family Ceramonematidae, present its history and diagnosis, as well as its respective genera, in addition to providing updated taxonomic lists of the valid species of each genus. For the taxonomic review, the Handbook of Zoology was first used to obtain information about the history and diagnosis, in addition to obtaining a list of its valid genera. Then, the original descriptions of each species were consulted, available on the checklists on the Nemys website. Based on the taxonomic review carried out in the respective study, Ceramonematidae has 7 valid genera and one inquerenda genus, being thus classified in previous works; totals 65 valid species, 2 inquerenda species, 10 nomen nudum species and the subfamilies Ceramonematinae and Pselionematinae are currently not valid. In addition, in some cases, it was found that the drawings of the original descriptions are very simplified and without much richness of details, which makes it difficult to visualize the cuticle ornamentation and to compare some structures, as the characteristics of the cuticle are important for identification at the species level. In this taxonomic review, tables and comparative figures for the species within each genus were developed, as well as lists of synonyms, species inquerenda and nomen nudum. Additionally, species and genera diagnoses were provided, adaptations were made whenever necessary, such as descriptions of the amphidian shapes of some species. Based on the survey of morphological characters of Ceramonematidae, it was concluded that the main characteristics that should be observed for the identification of genera are: number of cuticle ringlets, type of head arrangement, head capsule dimensions and amphidia shape. As for the species, the number of cuticle rings and the arrangement of the bristles in the cephalic capsule proved to be relevant in their differentiation. In this sense, for future work, an update of the original drawings and descriptions would be of great importance, as well as the elaboration of a taxonomic key for Ceramonematidae.