Zooidal budding in the cheilostomatous bryozoan Fenestrulina malusii var. thyreophora |
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Authors: | D P Gordon |
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Institution: | 1. Leigh Marine Laboratory , University of Auckland , Private Bag, Auckland, New Zealand;2. Biology Department , Dalhousie University , Halifax, Nova Scotia, Canada |
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Abstract: | Zooidal budding in Fenestrulina malusii var. thyreophora is described and notes on the budding of Micropora mortenscni are included for comparison. In both, an autozooidal bud arises from a membranous window in the exterior wall of a dietella. Dietellae themselves arise by being delimited as dichotomies of the developing lateral walls of autozooids. Because of the structural discreteness of dietellae of Fenestrulina and Micropora, and Hastings’ (1963) observation that some dietellae of Microporella occur as avicularia, dietellae in the Microporellidae and Micropora are regarded as fully formed heterozooids and not merely as incipient zooid buds, as lateral septulae are. The formation of dietellae in Fenestrulina and Micropora is a continuous process, and comparable with the con‐strictive budding of distal autozooids of Membranipora and Metrarabdotos. |
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Keywords: | Lake Rotoiti North Island underflow density current hypolimnetic stirring geothermal nutrients oxygen |
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