Sexually Dimorphic Cubomedusa Carybdea sivickisi (Cnidaria: Cubozoa) in Seto, Wakayama, Japan

Abstract

The small but distinctive cubomedusa Carybdea sivickisi has been reported from a range of tropical, subtropical, and mild temperate localities in the Pacific. In Japan, it has only definitively been documented in the subtropical region of Okinawa. However, in 1970 Uchida noted that three specimens from Seto, Wakayama, which he had referred to as Tamoya alata in 1929, were really C. sivickisi. The presence of this species as far north as Wakayama was questionable because of the confusion about the identity of the specimens and the fact that C. sivickisi had never been observed subsequently in this region. In August 2006, we discovered a population of this tiny species nearby the Seto Marine Biological Laboratory in Shirahama, Wakayama. In this paper we comment and clarify the geographical range, developmental morphology, and sexual behaviour of this species.

Sexual dimorphism in Tripedaliidae (Conant 1897) (Cnidaria, Cubozoa, Carybdeida)

“…In male medusae the purses were occupied by spermatophores, consistent with this species also producing spermatophores and having a mating behaviour similar to the other two species described by Werner (1973aWerner ( , 1976, Hartwick (1991), Lewis & Long (2005) and Lewis et al (2008).…”

Mass occurrence of the cubomedusa Copula sivickisi (Cnidaria: Cubozoa) at Seto Harbor, Shirahama, Wakayama, Japan, in summer of 2013; a possible recent example of global warming

“…Copula sivickisi was found at Shirahama, Wakyayama, Japan, only a few times for a century (1929,2006,2008) and in very small numbers (Uchida 1929;Lewis et al 2008;Kubota unpublished data). Shirahama, affected by the warm current Kuroshio, is the northernmost distribution locality in the world of this species (Lewis et al 2008).…”

“…Shirahama, affected by the warm current Kuroshio, is the northernmost distribution locality in the world of this species (Lewis et al 2008). During each night of the two days in early summer, we sampled more than 100 specimens in 30 minutes.…”

“…One of such small species is Copula sivickisi, described by Stiasny (1926) as Charybdea sivickisi, based on animals from the Philippines. The species, like other members of the family Tripedaliidae, presents sexual dimorphism (Straehler-Pohl et al in press) and exhibit complex copulatory bevaviour (Lewis & Long 2005;Lewis et al 2008). But their unique features are adhesive pads on the exumbrella that enable them to attach and rest in any substrate (Hartwick 1991).…”

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

“…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.…”