Observations on the anatomy, behaviour, reproduction and life cycle of the cubozoan Carybdea sivickisi

Hartwick, R. F.

doi:10.1007/978-94-011-3240-4_24

Cited by 30 publications

(50 citation statements)

References 8 publications

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“…However, some of the fossil forms are more complicated and are more highly specialized than extant cubozoans, which are generally noted for more complex behavior than other cnidarian classes [35] and are recognized as a “highpoint” in the development and evolution of cnidarians [36]. The analysis of the internal anatomy of these Cambrian fossil cubozoans undoubtedly offers invaluable implications for understanding the evolution of characteristics in cubozoans and the early radiations of medusozoans.…”

Section: Discussionmentioning

confidence: 99%

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Early Cambrian Pentamerous Cubozoan Embryos from South China

et al. 2013

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BackgroundExtant cubozoans are voracious predators characterized by their square shape, four evenly spaced outstretched tentacles and well-developed eyes. A few cubozoan fossils are known from the Middle Cambrian Marjum Formation of Utah and the well-known Carboniferous Mazon Creek Formation of Illinois. Undisputed cubozoan fossils were previously unknown from the early Cambrian; by that time probably all representatives of the living marine phyla, especially those of basal animals, should have evolved.MethodsMicroscopic fossils were recovered from a phosphatic limestone in the Lower Cambrian Kuanchuanpu Formation of South China using traditional acetic-acid maceration. Seven of the pre-hatched pentamerous cubozoan embryos, each of which bears five pairs of subumbrellar tentacle buds, were analyzed in detail through computed microtomography (Micro-CT) and scanning electron microscopy (SEM) without coating.ResultsThe figured microscopic fossils are unequivocal pre-hatching embryos based on their spherical fertilization envelope and the enclosed soft-tissue that has preserved key anatomical features arranged in perfect pentaradial symmetry, allowing detailed comparison with modern cnidarians, especially medusozoans. A combination of features, such as the claustrum, gonad-lamella, suspensorium and velarium suspended by the frenula, occur exclusively in the gastrovascular system of extant cubozoans, indicating a cubozoan affinity for these fossils. Additionally, the interior anatomy of these embryonic cubozoan fossils unprecedentedly exhibits the development of many new septum-derived lamellae and well-partitioned gastric pockets unknown in living cubozoans, implying that ancestral cubozoans had already evolved highly specialized structures displaying unexpected complexity at the dawn of the Cambrian. The well-developed endodermic lamellae and gastric pockets developed in the late embryonic stages of these cubozoan fossils are comparable with extant pelagic juvenile cubomedusae rather than sessile cubopolyps, whcih indicates a direct development in these fossil taxa, lacking characteristic stages of a typical cnidarian metagenesis such as planktonic planula and sessile polyps.

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Section: Discussionmentioning

confidence: 99%

“…Limited data known on cubozoan eggs or embryos are ranging from ca. 50 µm to 200 µm in diameter [35], [36], [47], [48]. Typically, the cubozoans eggs are set free from the gonads, leaving the exogonial pockets and to enter the central stomach cavity through the gastric ostia.…”

Section: Discussionmentioning

confidence: 99%

Early Cambrian Pentamerous Cubozoan Embryos from South China

et al. 2013

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“…( = Carybdea alata from Puerto Rico Arneson & Cutress [7], [8]), Carybdea xaymacana Conant, 1897 [32], [40], [41] , Carybdea sp. ( = Carybdea marsupialis from Puerto Rico, [94],[6] , Carybdea rastoni Haacke, 1887 [42] [5], Copula sivickisi (Stiasny, 1926) [43] [10], [12], [15] and Tripedalia cystophora Conant, 1897 [17], [20], [32], [41] have all shown internal fertilization occurs except in Morbakka virulenta (Kishinouye, 1910) where the gametes were released into the open water [16].…”

Section: Discussionmentioning

confidence: 99%

“…In C. sivickisi the developmental time in the different stages were extended by up to 150% compared to the other described cubozoan species. This might be due to the unique reproductive strategy in this species where they produce an embryo strand and the embryos are not released from it until they have reached the planula stage [10], [12], [15]. In Morbakka virulenta the embryonic development was postponed for 21 days after reaching the blastula stage by forming a cyst as resting stage [16].…”

Section: Discussionmentioning

confidence: 99%

“…The early life history has not yet been described for Carybdeida species belonging to the newly formed genus Alatina [1] In fact, life cycle knowledge is missing for the majority of the cubozoan species [2] only a small number having descriptions of the early stages of the life cycle [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14], [15], [16]. Only one complete life cycle, from spawning medusa through sessile stages to spawning medusa, has been published to date for the Caribbean cubozoan Tripedalia cystophora Conant, 1897 [17], [18], [19], [20], [21], [22], [23].…”

Section: Introductionmentioning

confidence: 99%

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Early Life History of Alatina cf. moseri Populations from Australia and Hawaii with Implications for Taxonomy (Cubozoa: Carybdeida, Alatinidae)

2014

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The early life stages of the cubomedusa Alatina cf. moseri from Osprey Reef (North Queensland, Australia) and Waikiki (Oahu, Hawaii) were studied using laboratory-based culturing conditions. Spawning populations from both regions were observed with reliable periodicity allowing polyp cultures from these locations to be collected and established under laboratory conditions. The polyps of this species were successfully reared from spawning adults. Polyps of Alatina cf. moseri were cultured at temperatures of 23–28°C, developed up to 19 tentacles and reached up to 1.70 mm in height. The balloon-shaped hypostomes possessed 4 well-defined lips. The polyps increased their numbers by means of formation of either sedentary polyp buds or creeping-polyp buds, which attached after 2–3 days. Metamorphosis occurred at temperatures of 25–28°C. Development of polyps and medusae were achieved for the first time within the genus Alatina and allowed comparisons of early life history between these and other species of the Carybdeida families. The metamorphosis and young medusa of this genus showed characters that differed distinctly from those noted for other Carybdeida species, but are very similar to the one described from Puerto Rico by Arneson and Cutress in 1976 for Alatina sp. (named by them Carybdea alata). Based on this evidence, the discrepancies in original specimen descriptions and the previous genetic comparisons, we support the suggestion that the two previously described species of Alatina from Australia and Hawaii (Alatina mordens and Alatina moseri) appear to represent artificial taxonomic units and may in fact be the same as the original Carybdea alata species named from Puerto Rico. Further taxonomic studies are desperately needed in order to clarify the various species and description discrepancies that exist within this newly proposed genus.

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Bilaterally symmetrical rhopalial nervous system of the box jellyfish Tripedalia cystophora

Skogh

Garm

Nilsson

et al. 2006

Journal of Morphology

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Cubomedusae, or box jellyfish, have the most elaborate visual system of all cnidarians. They have 24 eyes of four morphological types, distributed on four sensory structures called rhopalia. Box jellyfish also display complex, probably visually guided behaviors such as obstacle avoidance and fast directional swimming. Here we describe the strikingly complex and partially bilaterally symmetrical nervous system found in each rhopalium of the box jellyfish, Tripedalia cystophora, and present the rhopalial neuroanatomy in an atlas-like series of drawings. Discrete populations of neurons and commissures connecting the left and the right side along with two populations of nonneuronal cells were visualized using several different histochemical staining techniques and electron microscopy. The number of rhopalial nerve cells and their overall arrangement indicates that visual processing and integration at least partly happen within the rhopalia. The larger of the two nonneuronal cell populations comprises approximately 2,000 likely undifferentiated cells and may support a rapid cell turnover in the rhopalial nervous system.

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Observations on the anatomy, behaviour, reproduction and life cycle of the cubozoan Carybdea sivickisi

Cited by 30 publications

References 8 publications

Early Cambrian Pentamerous Cubozoan Embryos from South China

Early Cambrian Pentamerous Cubozoan Embryos from South China

Early Life History of Alatina cf. moseri Populations from Australia and Hawaii with Implications for Taxonomy (Cubozoa: Carybdeida, Alatinidae)

Bilaterally symmetrical rhopalial nervous system of the box jellyfish Tripedalia cystophora

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