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The Protonephridia of the Arctic Kinorhynch Echinoderes aquilonius (Cyclorhagida, Echinoderidae)
Author(s) -
Kristensen Reinhardt Møbjerg,
HaySchmidt Anders
Publication year - 1989
Publication title -
acta zoologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.414
H-Index - 37
eISSN - 1463-6395
pISSN - 0001-7272
DOI - 10.1111/j.1463-6395.1989.tb01048.x
Subject(s) - biology , anatomy , excretory system , ectoderm , lamina , bilateria , basal lamina , cilium , microbiology and biotechnology , ultrastructure , embryo , embryogenesis , biochemistry , gene , phylogenetic tree
The cyclorhagid kinorhynch Echinoderes aquilonius Higgins & Kristensen, 1988 possesses a single pair of protonephridia located in segments 10 and 11. The protonephridia consist of: (1) three terminal cells T‐1, T‐2. T‐3 , each with two cilia; (2) a single non‐ciliated canal cell; (3) a nephridiopore cell with many microvilli and a cuticular sieve plate. The protonephridia of Echinoderes are presumed to develop from the ectoderm near the area of the sieve plate on the eleventh segment, and are suspended in the dorso‐lateral pseudocoelomic cavity where they are surrounded by a basal lamina. One of the terminal cells ( T‐1 ) secondarily penetrates the basal lamina of the tenth segment and a part of the cell attaches to the cuticle. The kinorhynch protonephridia are compared with the excretory organs of other Bilateria. expecially the ‘aschelminths’, and apomorphic characters of the kinorhynch protonephridia are defined.