Phosphatic spicules in the nematocyst batteries of Nanomia cara (Hydrozoa, Siphonophora)

Mackie, G. O.; Marx, Roswitha M.

doi:10.1007/bf00539784

Cited by 5 publications

(8 citation statements)

References 10 publications

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“…Eruption of siphonophore tentilla is an explosive process studied only once in recent times, by Mackie and Marx [155] in the small physonect Nanomia bijuga (then thought to be N. cara ). A looped elastic strand of mesogloeal origin extends distally inside the tentillum from the pedicel to the origin of the terminal filament ( Figure 15A–C ), and plays an important role in tentillum discharge; it allows the cnidoband to slap onto the prey whilst still remaining attached to the pedicel.…”

Section: Resultsmentioning

confidence: 99%

“…During feeding, the terminal filament relaxes and extends well beyond the tentillum ( fig. 1A [155] ) to ensnare unsuspecting prey. Pulling down on the filament causes eruption of the cnidoband, which tears the spongy ectodermal tissue as it uncoils.…”

Section: Resultsmentioning

confidence: 99%

“…Pulling down on the filament causes eruption of the cnidoband, which tears the spongy ectodermal tissue as it uncoils. After eruption, Mackie and Marx [155] find that the elastic strand remains firmly attached to the axial canal at its proximal end and to the cnidoband at its distal end ( Figure 15F , ‘cb’); attachment is enhanced in physonects by phosphatic spicules [155] . The struggling prey is brought to the cnidoband by contraction of the terminal filament, and rapidly stunned by multiple discharge of the haploneme and heteroneme nematocysts of the cnidoband.…”

Section: Resultsmentioning

confidence: 99%

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Global Diversity and Review of Siphonophorae (Cnidaria: Hydrozoa)

Mapstone

2014

PLoS ONE

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In this review the history of discovery of siphonophores, from the first formal description by Carl Linnaeus in 1785 to the present, is summarized, and species richness together with a summary of world-wide distribution of this pelagic group within the clade Hydrozoa discussed. Siphonophores exhibit three basic body plans which are briefly explained and figured, whilst other atypical body plans are also noted. Currently, 175 valid siphonophore species are recognized in the latest WoRMS world list, including 16 families and 65 genera. Much new information since the last review in 1987 is revealed from the first molecular analysis of the group, enabling identification of some new morphological characters diagnostic for physonect siphonophores. Ten types of nematocysts (stinging cells) are identified in siphonophores, more than in any other cnidarian; these are incorporated into batteries in the side branches of the tentacles in most species (here termed tentilla), and tentilla are reviewed in the last section of this paper. Their discharge mechanisms are explained and also how the tentilla of several physonect siphonophores are modified into lures. Of particular interest is the recent discovery of a previously unknown red fluorescent lure in the tentilla of the deep sea physonect Erenna, the first described example of emission of red light by an invertebrate to attract prey.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Global Diversity and Review of Siphonophorae (Cnidaria: Hydrozoa)

Mapstone

2014

PLoS ONE

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“…In siphonophores, mature nematocysts are found concentrated in knobbed structures on the tentacles called cnidosacs (Skaer 1988). The tentacles of Stephanophytes superba (Chun 1891) and Nanomia cara (Mackie and Marx 1988;Mackie 1999) bear highly organized nematocyst batteries on numerous side branches (tentilla), which erupt when prey comes into contact with them. A large N. cara can have as many as 80 tentacles with some 1500 nematocyst batteries, six million nematocysts, and an effective circumferential spread of 3-4 m (Mackie 1999).…”

Section: Introductionmentioning

confidence: 99%

The behavioral and developmental physiology of nematocysts

Kass-Simon¹,

Scappaticci²

2002

Can. J. Zool.

189

143

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Nematocysts are the nonliving secretions of specialized cells, the nematocytes, which develop from multipotent stem cells. Nematocysts are the means by which coelenterates capture prey and defend against predation. The 25 or more known types of nematocysts can be divided into to four functional categories: those that pierce, ensnare, or adhere to prey, and those that adhere to the substrate. During development a collagenous cyst, which may contain toxins, forms; a hollow thread, which becomes coiled as it invaginates, develops. Maturing nematocytenematocyst complexes migrate to their discharge sites and are deployed in specific patterns. The mechanisms of pattern determination are not clear. Discharge of nematocysts appears to involve increases in intracapsular osmotic pressure consequent upon release of bound calcium within the capsule; the eversion of the filament may depend upon release of structural tension consequent upon a loss of zinc from the thread. Evidence exists that discharge is initiated as a calcium-dependent exocytosis, triggered by an electrical signal resulting from the transduction of mechanical stimuli received at the nematocyte's cnidocil. Chemical signals transduced in adjacent sensory cells alter the frequency response of the nematocyte. In opposition to the nematocyte-nematocyst independent effector hypothesis, excitatory and inhibitory neuronal input appears to regulate discharge.Résumé : Les nématocystes sont des sécrétions non vivantes produites par des cellules spécialisées, les nématocytes, qui proviennent de cellules souches multipotentes. Chez les coelentérés, les nématocystes servent à la capture des proies et sont des armes de défense contre les prédateurs. Les quelque 25 types connus de nématocystes peuvent se diviser en quatre catégories fonctionnelles : ceux qui percent, ceux qui servent de pièges, ceux qui adhèrent aux proies et ceux qui adhèrent au substrat. Au cours du développement, il se forme un kyste de collagène qui peut contenir des toxines; un fil creux se déploie en spirale en s'invaginant. Les complexes nématocytes-nématocystes migrent vers leur site de vidange et ils sont disposés selon un arrangement particulier. Les mécanismes qui régissent cet arrangement sont mal connus. L'expulsion des nématocystes semble se faire par augmentation de la pression osmotique intra-capsulaire consécutive à la libération du calcium lié dans la capsule; l'évagination du filament peut dépendre du relâchement de la tension structurale qui se produit lors de la perte du zinc du filament. Il semble, d'après certains indices, que l'expulsion des nématocystes soit d'abord une exocytose dépendant du calcium, un processus déclenché par un signal électrique résultant de la transduction de stimulus mécaniques perçus au niveau du cnidocil du nématocyte. Les stimulus chimiques modifiés par transduction dans des cellules sensorielles adjacentes modifient la fréquence de la réponse du nématocyte. En contrepartie de l'hypothèse d'un effecteur indépendant nématocyte-nématocyste, il faut envisager c...

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“…There is, however, some evidence of phosphatic biomineralisation. The nematocyst batteries of the siphonophore Nanomia cara have bands of calcium phosphate spicules (Mackie and Marx 1988;Watabe 1990). Amorphous Mg-Ca phosphate is documented in the statoconia of the hydrozoan medusa Aglantha, Lovenella, Obelia, and Phyalidium (Chapman 1985).…”

Section: Discussionmentioning

confidence: 99%

Conulariid–like fossil from the Vendian of Russia: a metazoan clade across the Proterozoic/Palaeozoic boundary

Ivantsov

Fedonkin

2002

Palaeontology

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A conulariid-like fossil is described for the ®rst time from Upper Vendian (late Neoproterozoic) deposits. Vendoconularia triradiata gen. et sp. nov. is found with other fossils in poorly cemented, siliciclastic deposits of the lower part of the Ust'-Pinega Formation, exposed in the middle reaches of the Onega River, north of the Russian Platform. This fossil assemblage, stratigraphically lowermost in the region, includes Swartpuntia Narbonne, endemic Ventogyrus Ivantsov and Grazhdankin, Calyptrina-like tubular forms, and other new, as yet undescribed, species. Vendoconularia is described here using morphological terms developed for conulariids owing to their striking similarity. However, the six faces of the conical test and three-fold symmetry may re¯ect some phylogenetic connection with the larger clade of Trilobozoa, a cnidarian class that radiated during the Late Vendian±Early Cambrian and then became extinct.

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Phosphatic spicules in the nematocyst batteries of Nanomia cara (Hydrozoa, Siphonophora)

Cited by 5 publications

References 10 publications

Global Diversity and Review of Siphonophorae (Cnidaria: Hydrozoa)

Global Diversity and Review of Siphonophorae (Cnidaria: Hydrozoa)

The behavioral and developmental physiology of nematocysts

Conulariid–like fossil from the Vendian of Russia: a metazoan clade across the Proterozoic/Palaeozoic boundary

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