REPRODUCTION AND DEVELOPMENT OF THE HERMAPHRODITIC SEA-STAR,ASTERINA MINORHAYASHI

Chromosomes of Japanese Starfishes

“…The karyotypes of A. pectinifera and A. minor were similar but differed in number of meta-and submetacentric chromosomes. Though A. pectinifera and A. minor belong to the same genus, they differ in the size and yolk content of eggs and in type of larval development-indirect (A. pectinifera; Komatsu, 1984) VS. direct (A. minor ; Komatsu et al, 1979). Immunological data indicate that A. pectinifera differs considerably from A. minor compared with other species belonging to genus Asterina (Mochizuki and Hori, 1980;Matsuoka, 1981).…”

“…While extensive morphological (Fisher, 1911(Fisher, , 1928(Fisher, , 1930Hayashi, 1940Hayashi, , 1943Hayashi, , 1973Spencer and Wright, 1966;Fell, 1963;Heddle, 1967;Blake, 1987;Downey, 1973;Clark and Downey, 1992), developmental (Oguro et al, 1976;Komatsu et al, 1979;McEdward, 1992;Chia et al, 1993;Byrne and Cerra, 1996), biochemical (Kubo, 1961;Schopf and Murphy, 1973;Mochizuki and Hori, 1980;Matsuoka, 1981, Matsuoka et al, 1994, and molecular (Lafay et al, 1995;Wada et al, 1996;Knott and Wray, 2000) studies have been systematically carried out on starfishes, cytogenetic studies have not yet been applied to asteroid phylogeny.…”

Selfing in Parvulastra exigua: an asterinid sea star with benthic development

“…Hermaphroditism, in its various forms, is characteristic of many abundant marine invertebrates with small adult size including echinoderms, cnidarians, molluscs, and ascidians (Emson and Crump 1979;Komatsu et al 1979;Yamagata 1982;Byrne 1991;Jarne and Charlesworth 1993;Ó Foighil 1989;Jarne and Auld 2006;Boissin et al 2008). For many of these species with benthic development, a mixed mating system (selfing ?…”

“…Release of sperm onto communal egg masses by aggregated P. exigua and Aquilonastra minor is a form of pseudocopulation (Komatsu et al 1979;Byrne 1992Byrne , 2005. The recently discovered Aquilonastra byrneae may also have this reproductive strategy (Byrne and Walker 2007).…”

“…They exhibit a diversity of planktonic and benthic (e.g., benthic egg laying, brooding) developmental modes (Byrne 2006). Gonad development ranges from gonochorism in broadcast spawners, protandrous hermaphroditism in egg laying species (e.g., Asterina gibbosa) to simultaneous hermaphroditism in brooders (e.g., Asterina phylactica, Cryptasterina hystera, Parvulastra vivipara) (Emson and Crump 1979;Komatsu et al 1979;Yamagata 1982;Byrne 1996). Parvulastra exigua, a species that deposits egg masses with no subsequent parental care, exhibits protrandry-like hermaphroditism with small individuals being predominantly male and large individuals being predominantly female or male, with a few simultaneous hermaphrodites present, particularly in the intermediate size individuals (Byrne 1992).…”