DOI: 10.1111/zsc.70091 ISSN: 0300-3256
Phylogeny of the Bakuellid‐Related Ciliate (Alveolata, Ciliophora) Genera, With Establishment of Three New Families and Note on Morphogenesis of
Holostichides heterotypicus
Lijian Liao, Limin Jiang, Xiaozhong Hu ABSTRACT
The order Urostylida Jankowski, 1979 remains taxonomically challenging due to incomplete morphological and morphogenetic data for many species. To clarify the relationships within genera such as
Holostichides
Foissner, 1987 and
Paragastrostyla
Hemberger, 1985, we investigated the morphology of
Holostichides heterotypicus
and two
Paragastrostyla
species (
P. lanceolata
and
P. terricola
) and redefined relevant genera and species. In addition, we supplemented the morphogenetic traits of
H
.
heterotypicus
. We provided the first multiple‐gene sequence data for the genus
Paragastrostyla
and revealed, through multi‐ribosomal and mitochondrial COI gene trees, that it occupies a distinct phylogenetic position together with the genus
Holostichides
. Based on molecular phylogenetic analyses and consistent morphological characteristics shared among
Paragastrostyla
,
Holostichides
and
Eschaneustyla
, we propose a new family, Paragastrostylidae fam. nov., to accommodate these three genera. Furthermore, we evaluated the taxonomic status of the Bakuellidae and found that so‐called ‘bakuellids’ can be divided into several independent and robust clades based on ribosomal gene trees. Based on integrated morphological and molecular data, we propose establishing two additional new families, namely Australothridae fam. nov. (including
Australothrix
and
Anteholostichides
) and Metaurostylopsidae fam. nov. (including
Metaurostylopsis
and
Monourostylopsis
). Additionally, the COI gene is recognised as an unreliable marker for distinguishing higher taxa of ciliates.