A synopsis of Antarctic plagiostomids (Platyhelminthes, Prolsecithophora), with the description of a new species and remarks on taxonomy, phylogeny, and biogeography
- Expert-center for Taxonomic Identification, Institute of Taxonomic Zoology, University of Amsterdam, P.O. Box 4766, 1009, AT Amsterdam, The Netherlands
A synopsis is provided of the Antarctic plagiostomid flatworms of the genera Plagiostomum, Plicastoma, and Haploophorum, including one new species, Plagiostomum giganteum sp. nov. The new species is characterized by a relatively large size, absence of a ciliated furrow, short common oviduct which expands to form a diverticulum, strongly muscular and glandular distal sac, well devdoped proximal penis, pharynx variabilis textus, and a terminal mouth. A phylogenetic analysis is performed on the Plagiostomum-group, comprising the genera Plicastoma, Haploophorum, Acmostomum, Tuilica, and Plagiostomum. The analysis is based on 12 terminal taxa and 6 characters (ciliated furrow, infranucleate epidermis, unpaired ovary, paired ovaries, plicate pharynx, pharynx variabilis). The phylogenetic tree proposed has a length of 10 steps and a consistency index of 0.60. The monotypic genus Tuilica grouped with representatives of Acmostomum and it is therefore suggested that T. evelinae is best considered as a species of Acmostomum. In the phylogeaetic tree the genus Plicastoma is positioned at the outgroup node, Plagiostomum is the sister genus of Haploophorum and Acmostomum together, and these last two are sistergroups. Generalized distribution maps are given for the genera Haploophorum, Acmostomum, Plicastoma, and Plagiostomum.
- 1 - sciences appliquees, technologies et medecines
- 2 - sciences biologiques et medicales
- 3 - sciences biologiques fondamentales et appliquees. psychologie
- 1 - Life Sciences ; 2 - Agricultural and Biological Sciences ; 3 - General Agricultural and Biological Sciences