The corona ciliata of Chaetognatha (arrow worms) is a circular or elliptical groove lined by a rim from which multiple lines of cilia emanate, located dorsally on the head and/or trunk. Mechanoreception, chemosensation, excretion, respiration, and support of reproduction have been suggested to be its main functions. Here we provide the first experimental evidence that the cilia produce significant water flow, and the first visualisation and quantification of this flow. In Spadella cephaloptera, water is accelerated toward the corona ciliata from dorsal and anterior of the body in a funnel-shaped pattern, and expelled laterally and caudally from the corona, with part of the water being recirculated. Maximal flow speeds were approximately 140μms in adult specimens. Volumetric flow rate was Q=0.0026μls. The funnel-shaped directional flow can possibly enable directional chemosensation. The flow measurements demonstrate that the corona ciliata is well suited as a multifunctional organ.
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http://dx.doi.org/10.1016/j.zool.2017.09.001 | DOI Listing |
J Exp Zool B Mol Dev Evol
July 2023
Developmental Biology Unit, European Molecular Biology Laboratory, Heidelberg, Germany.
The phylogenetic position of chaetognaths, or arrow worms, has been debated for decades, however recently they have been grouped into the Gnathifera, a sister clade to all other Spiralia. Chaetognath photoreceptor cells are anatomically unique by exhibiting a highly modified cilium and are arranged differently in the eyes of the various species. Studies investigating eye development and underlying gene regulatory networks are so far missing.
View Article and Find Full Text PDFZookeys
June 2022
Big data Fishery Resource Management Interdisciplinary Program, Chonnam University, Yeosu 59626, Republic of Korea.
Since the first record of chaetognaths (arrow worms) reported from Korean waters by Molchanov in 1907, three families, 12 genera and 21 species have been additionally described. Eighteen of the 21 recorded species have been reported under scientific names different from the latest taxonomic system. This study aimed to address this issue by conducting a taxonomic re-evaluation of chaetognaths collected from Korean waters.
View Article and Find Full Text PDFEur J Protistol
October 2022
Department of Biological Sciences and Bioengineering, Inha University, Incheon 22212, South Korea. Electronic address:
The morphology and molecular phylogeny of a new soil ciliate, Keronopsis koreana n. sp., which was discovered in soil from Jindo-gun, South Korea, were investigated.
View Article and Find Full Text PDFJ Eukaryot Microbiol
January 2021
Laboratory of Protozoological Biodiversity and Evolution in Wetland, College of Life Sciences, Shaanxi Normal University, Xi'an, 710119, China.
The morphology, morphogenesis and molecular phylogeny of Parabistichella dieckmanni (Foissner, 1998) Foissner, 2016, isolated from north China, were investigated. The Chinese population was characterized as having five to seven frontal cirri in corona, four to seven buccal cirri arranged in a row, two to four short frontal rows and two long frontoventral rows, three to seven transverse cirri, four macronuclear nodules, three dorsal kineties following a Gonostomum-pattern, and caudal cirri absent. Morphogenetic research reveals that the main characteristics during binary fission are as follows: (1) the long left frontoventral row is formed by two or three anlagen; (2) the posterior part of the parental adoral zone of membranelles is renewed, and the oral primordium of the opisthe is formed intrakinetally; (3) FVT-anlagen I to VI (or V, VII) produce each a frontal cirrus to form the frontal corona; (4) development of dorsal kineties follows the Gonostomum-pattern.
View Article and Find Full Text PDFEur J Protistol
April 2019
Consulting Engineering Office for Ecology, Radetzkystrasse 10, 5020 Salzburg, Austria.
Paraholosticha muscicola, type species of Paraholosticha Wenzel, inhabits mainly terrestrial habitats, but also freshwater. A brackish water population from Korea is described, the first record from such a habitat. Principal component analysis shows that this population is more similar to a terrestrial population from Denmark than to a population from Antarctic soil.
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