Seasonal reproductive cycles of three Australian species of chitons (Mollusca: Polyplacophora)

Abstract

1Studies were made of the seasonal reproductive cycles of Chiton pe/liserpentis, Onithochiton quercinus and Plaxiphora paeteliana. All are dioecious and not sexually dimorphic. The sex ratio is 1 : 1 in P. paeteliana, but is biased 2 : 1 in favour of males in 0. quercinus and C. pelliserpentis.The two chitonid species exhibited a bimodal reproductive cycle: 0. quercinus spawned in spring and autumn, with a peak in autumn and C. pe/liserpentis spawned in spring and autumn, with a peak in spring. The mopaliid P. paeteliana spawned for several months in spring and autumn, and the nature of the pattern was less clear.Gametogenesis in all species occurred during periods of increasing sea temperatures in late spring and early summer and during periods of decreasing temperature in late autumn, in each case following spawning. Phytoplankton levels were high at the time of spawning, although the larvae are presumed to be lecithotrophic.

Observation and establishment of gonad development stages in polyplacophorans (Mollusca): Chiton (Chiton) articulatus a case study

“…Other studies about the reproductive season (also called spawning periodicities, reproductive periodicities, seasonality of reproduction, reproductive activity, reproductive event, reproductive state, and/or breeding season) in polyplacophorans used histology but not scales of GDS (except by Sakker ; Ishiyama‐C. et al .…”

“…; Lawrence et al . ; Murti and Nagabhushanam ; Webber and Giese ; Glynn ; Barnes ; Himmelman , ; Pearse ; Nagabhushanam and Deshpande ; Cruz and Sotela ; Sakker ; Peña‐Monardez et al . ; Yoshioka ; Currie ; Soliman et al .…”

“…The regressed and/or regenerating terms of Sakker () were neither used in our study, because they are concepts that generally refer to a particular phenomenon that implies processes of repair, restoration, reconstitution and/or regeneration, which follow traumatic or self‐induced damage (autotomy) of any organ; e.g., in the holothurians (Candia‐Carnevali et al . ).…”

“…). However, these features have gone unnoticed and have not been taken into account in the histological studies on the reproductive cycle and reproductive season in polyplacophorans (except by Sakker ; Ishiyama‐C. et al .…”

Variation In Abundance And Size-Structure Of Populations Of The Small Chiton, Acanthochitona Retrojecta

“…Previous research on chitons has focused predominantly on their reproductive biology (e.g. Pearse, 1979;Sakker, 1986;Eernisse, 1988;Currie, 1990) and behaviour (e.g. see review in Crozier, 1921;Boyle, 1977;Chelazzi, Focardi & Deneubourg, 1983).…”