title: Morphology, morphogenesis, and molecular phylogeny of Sterkiella tetracirrata n. sp. (Ciliophora, Oxytrichidae), from the Silent Valley National Park, India.
abstract: The morphology and morphogenesis during cell division of Sterkiella tetracirrata n. sp., isolated from a soil sample collected from the Silent Valley National Park, Kerala, India, were investigated using live observation, protargol staining and scanning electron microscopy. The new species differs from its congeners by the following combination of features: cell size in vivo 85-110×35-50μm, on average 84×37μm in protargol preparations; four ellipsoidal macronuclear nodules; 31 adoral membranelles; 17 frontal-ventral-transverse cirri consisting of three frontal, four frontoventral, one buccal, three ventral, two pretransverse and invariably four transverse cirri; resting cyst with separate macronuclear nodules. Sterkiella tetracirrata differs from the similar species S. terricola in the number of transverse cirri (invariably 4 vs. 3) and in the number of adoral membranelles (24-35 vs. 22 or 23). Morphogenesis resembles that of its congeners S. nova and S. histriomuscorum. Phylogenetic analyses based on SSU rRNA gene sequences consistently place the new species within the stylonychine oxytrichids, clustering closer to Gastrostyla steinii than to either S. cavicola or S. histriomuscorum. The analyses support the morphological evidence (e.g., similarity in the oral apparatus and the dorsal kinety pattern) that Gastrostyla and Pattersoniella evolved from a Sterkiella-like ancestor.
authors.affiliation: Ciliate Biology Laboratory, Sri Guru Tegh Bahadur Khalsa College, University of Delhi, Delhi 110 007, India; School of Environmental Science, University of Camerino, Via Gentile III da Varano, 62032 Camerino (MC), Italy. Electronic address: santoshcbio@gmail.com.
authors.forename: Santosh
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Ciliate Biology Laboratory, Sri Guru Tegh Bahadur Khalsa College, University of Delhi, Delhi 110 007, India. Electronic address: komalkamra@yahoo.com.
authors.forename: Komal
authors.initials: K
authors.lastname: Kamra
authors.affiliation: School of Environmental Science, University of Camerino, Via Gentile III da Varano, 62032 Camerino (MC), Italy.
authors.forename: Daizy
authors.initials: D
authors.lastname: Bharti
authors.affiliation: School of Environmental Science, University of Camerino, Via Gentile III da Varano, 62032 Camerino (MC), Italy.
authors.forename: Antonietta
authors.initials: A
authors.lastname: La Terza
authors.affiliation: Department of Zoology, University of Delhi, Delhi 110 007, India.
authors.forename: Neeta
authors.initials: N
authors.lastname: Sehgal
authors.affiliation: Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK.
authors.forename: Alan
authors.initials: A
authors.lastname: Warren
authors.affiliation: Ciliate Biology Laboratory, Sri Guru Tegh Bahadur Khalsa College, University of Delhi, Delhi 110 007, India.
authors.forename: Gulshan Rai
authors.initials: GR
authors.lastname: Sapra
mesh_terms: D016798:Ciliophora / Q000145:classification / Q000235:genetics / Q000648:ultrastructure; D007194:India; D008855:Microscopy, Electron, Scanning; D008969:Molecular Sequence Data; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012987:Soil / Q000469:parasitology
chemical_list: D012337:RNA, Ribosomal, 18S; D012987:Soil
keywords: India; Morphogenesis; Phylogeny; Soil ciliate; Sterkiella tetracirrata n. sp.; Stylonychine oxytrichids