Development and polyp formation of the giant box jellyfish Morbakka virulenta (Kishinouye, 1910) (Cnidaria: Cubozoa) collected from the Seto Inland Sea, western Japan

Abstract

Abstract:The giant cubozoan Morbakka virulenta was collected from the central part of the Seto Inland Sea, western Japan in October 2009, in order to observe its development and polyp formation. Fertilization occurred externally. Demersal fertilized eggs were obtained during the incubation of mature females and males kept at a temperature of ca. 17 to 21°C. From the two-cell stage onwards, fertilized eggs developed into blastulae within 4 h. The development of the blastulae stopped for 21 days after forming blastocysts. This formation of blastocysts is up to now unique within the Cnidaria. The planulae, which developed inside the cysts and lacked larval ocelli, this being characteristic for the Cubozoa, finally metamorphosed into polyps bearing only a single tentacle. The 16-tentacledstage in polyps was reached about three months after this metamorphosis. Budding occurred in eight-tentacled polyps and swimming polyps were released nine days after the commencement of budding. These unique developmental features of M. virulenta may shed additional light on the evolution of life history strategies in the Cnidaria.

Box JellyfishAlatina alataHas a Circumtropical Distribution

“…The mechanisms involved in piercing the membrane were not investigated here, nor was the composition of the perisarc. Our findings resemble, to a certain extent, the “blastocysts” reported in Morbakka virulenta by Toshino et al (2013), but in the case of M. virulenta, polyps (not zygotes) formed cysts that endured adverse conditions for many months, reemerging as polyps (not planulae).…”

Scolionema sanshin sp. n., a new species (Hydrozoa, Limnomedusae, Olindiidae) from the Ryukyu Archipelago, southern Japan

“…Male and female medusae collected from Nago were kept in a deep petri-dish (diameter 149 mm, height 91 mm, water volume 1500 mL) with filtered seawater (1 µm) at about 30°C in the laboratory at Kitasato University. Different developmental stages (medusa, primary, and mature polyps) were maintained, following procedures described by Toshino et al (2013). Primary polyps were transferred to petridishes (diameter 78 mm, height 24 mm) filled with filtered seawater (1 µm) and kept at 30°C.…”

Rediscovery and description of the cubomedusa <i>Alatina grandis</i> (Agassiz & Mayer, 1902) (Cnidaria: Cubozoa: Alatinidae) from Pakistani waters

“…Morbakka virulenta with a bell height of up to 250 mm (Toshino et al 2013); Tamoyidae: Tamoya haplonema with a bell height of up to 165 mm (Haeckel 1880, pers. observation) and Alatinidae: Alatina grandis with a bell height of up to 240 mm (Agassiz & Mayer 1902, Mayer 1910, 1917, Stiasny 1937 or Keesingia gigas with a bell height in the immature holotype of 190 mm and of ca.…”

“…de). But besides this, the group also presents other interesting aspects, like courtship (Lewis & Long 2005, Lewis et al 2008, Garm et al 2012, Chiaverano et al 2013, Canepa et al 2014, Carrette et al 2014, vision (Coates 2003, Nordström et al 2003, Nilsson et al 2005, Garm et al 2006, 2007a+b, 2008, Garm & Bielecki 2008 and taxonomic classification (Bigelow 1938, Werner 1973, Gershwin 2005b, 2006, Straehler-Pohl 2014, Toshino et al 2013. Also the validity of some species, especially the ones of the alatinid family, has been discussed since the beginning of the last century (Mayer 1910, Bigelow 1938, Kramp 1961, Gershwin 2005a, b, Bentlage 2010, Lewis et al 2013.…”