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Synergistic effects of combining morphological and molecular data in resolving the phylogenetic position of S emispathidium ( C iliophora, H aptoria) with description of S emispathidium breviarmatum sp. n. from tropical Africa
Author(s) -
Vďačný Peter,
Foissner Wilhelm
Publication year - 2013
Publication title -
zoologica scripta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.204
H-Index - 64
eISSN - 1463-6409
pISSN - 0300-3256
DOI - 10.1111/zsc.12023
Subject(s) - biology , phylogenetic tree , evolutionary biology , phylogenetics , lineage (genetic) , taxon , morphology (biology) , zoology , most recent common ancestor , gene , genetics , botany
We describe a new species, S emispathidium breviarmatum sp. n., from tropical Africa and analyse its phylogenetic position within the subclass Haptoria, using live observation, various silver impregnation methods, SEM and the 18S r RNA gene. S emispathidium breviarmatum differs from its congeners by the much higher number of ciliary rows and by the shape and size of the extrusomes, that is, extrusive organelles that kill the prey. The phylogenetic position of S emispathidium is controversial due to its ‘hybrid’ morphology. Specifically, the cylindroidal body has a more or less discoidal oral bulge indicating an enchelyodonid origin, while the anteriorly curved somatic kineties suggest a spathidiid ancestor. In order to reconstruct the evolutionary history of S emispathidium and to unravel its affinity to other haptorians, we used synergistic effects of combining morphological and molecular data coming from 34 haptorian taxa. These analyses show that Semispathidium belongs to the order Spathidiida representing a basal lineage that is far from ordinary Spathidium species, but very likely related to P rotospathidium and E nchelys . Any closer phylogenetic relationship between S emispathidium and Enchelyodon spp. is not recognized in morphological and molecular phylogenies and is consistently excluded by statistical tree topology tests.