HEXACTINELLIDA AFTER 132 YEARS OF STUDY -- WHAT’S NEW?

Autores/as

  • HENRY M. REISWIG

Resumen

The presently used taxonomic arrangement of Hexactinellida has been reached through a series of modifications introduced at 10-year intervals. The place of Hexactinellida within the Porifera remains controversial in spite of advances in knowledge of soft-tissue structure and several molecular sequence studies. New observations on development of Oopsacas minuta confirm classic work on Farrea sollasi, and conclude that early cleavage is complete, suggesting hexactinellids are primary cellular organisms. Analysis of postlarval and juvenile skeletal formation is expected to be useful for unraveling phyletic relationships, and an example of Leucopsacas scoliodocus is explored. Hexactinellid species populations are generally thought to be sparsely distributed over fairly large geographic ranges. Historic early dredging and recent photographic sled and submersible surveys show dense hexactinellid populations of single- or multi-species communities extending over several kilometers. Factors conducive to large patch development and maintenance are under investigation.

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Publicado

2018-05-22