A New Subspecies of Oxytricha granulifera (Hypotrichia: Oxytrichidae) from Mexico, with Notes on its Morphogenesis and Phylogenetic Position

Abstract

The genus Oxytricha Bory de Saint-Vincent in Lamouroux, Bory de Saint-Vincent and Deslongchamps, 1824 comprises about 38 species distributed worldwide and has been considered to be a nonmonophyletic group. Based on living observations, protargol preparations, and a small subunit ribosomal RNA (SSU rRNA) gene sequence, we describe a new subspecies Oxytricha granulifera chiapasensis n. subsp. This new taxon is morphologically characterized by undulating membranes basically in a Stylonychia-pattern, six dorsal kineties, size in vivo ca. 60-120 × 20-40 μm, 21-30 right and 21-31 left marginal cirri, 22-29 adoral membranelles, and spherical cortical granules arranged in longitudinal rows on the dorsal side. In terms of the SSU rRNA gene sequence, the new subspecies differs from populations of O. granulifera from GENBANK by 7-35 nucleotides. Phylogenetic analyses showed that Oxytricha granulifera gene sequences were nested into three groups, with the new subspecies included in one of them. Oxytricha granulifera chiapasensis n. subsp. is different from Oxytricha granulifera granulifera Foissner and Adam, 1983 and Oxytricha granulifera quadricirrata Blatterer and Foissner, 1988 based on: (i) undulating membranes in Stylonychia-pattern, (ii) formation of a sixth dorsal kinety during morphogenesis, (iii) the adoral membranelles number, and (iv) inhabiting freshwater habitats.

Morphogenesis and Molecular Characterization of a Little Known Soil Ciliate, Oxytricha nauplia Berger et Foissner, 1987 (Ciliophora, Sporadotrichida)

“…So far morphogenetic data are available for very few species in the genus Oxytricha, which, however, reveals diverse patterns (Berger 1999;Shao et al 2015;Foissner 2016;Méndez-Sánchez et al 2018). Formation of each streak is hard to confirm because of the lack of some critical stages.…”

“…Based on data available (Foissner and Adam 1983), it may be derived from the postoral ventral cirrus or newly formed. Oxytricha nauplia has the same origin of oral primordium as in O. granulifera and O. pulvillus in which oral primordium begins with proliferation of basal bodies between cirrus V/3 and cirrus V/2 (Foissner 2016;Méndez-Sánchez et al 2018).…”

“…Like Oxytricha pulvillus, O. nauplia consistently develops two anlagen to the anterior right and front of the right marginal row anlage, which give rise to two dorsomarginal kineties in interphase specimens (Foissner 2016), while O. granulifera forms one or two dorsomarginal kineties anlagen (Berger 19999;Méndez--Sánchez et al 2018).…”

“…The genus Oxytricha Bory de Saint-Vincent, 1824 is one of the oldest genera of oxytrichids and so far comprises about 50 species distributed worldwide (Berger 1999;Shao et al 2014;Foissner 2016). Some have overlapping species-level characters with respect to their living morphology, ciliature, morphometric data and habitat (Berger and Foissner 1989;Berger 1999;Foissner and Stoeck 2006;Shao et al 2011Shao et al , 2014Shao et al , 2015Méndez-Sánchez et al 2018). Its systematics, however, has traditionally been highly confused, not least because a properly defined type species was not fixed until relatively recently (Berger 1999).…”

Cell-division pattern and phylogenetic position of a new ciliate genus Parasincirra n. g. (Protista, Ciliophora, Hypotrichia), with report of a new soil species, P. sinica n. sp. found from northwest China

“…As the most diverse linages of ciliates, the subclass Hypotrichia Stein, 1859 has been the subject of much research. A consistent focus in that research has been the use of silver staining methods to reveal species characteristics that are important for taxonomic classification and for determining the morphogenetic processes, as well as the use of molecular technologies to reveal their evolutionary relationships [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. And even so, overall previous findings failed to recover the monophyly of Hypotrichia and the classification, validity, delimitation and phylogenetic relationships among and within these groups remains problematic [26,27].…”