An interesting association between Neosphaera coccolithomorpha and Ceratolithus cristatus (Haptophyta)

Segura, Jesús Ángel Alcober; Jordan, Richard W.

doi:10.1017/s0967026296001047

Cited by 7 publications

(9 citation statements)

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“…(3) Non-motile cells enclosed by a normal coccosphere of imbricating planolith coccoliths. These were formerly regarded as a separate species, Neosphaera coccolithomorpha but combination cells of hoop coccoliths and planoliths, and even of hoop coccoliths, planoliths and ceratoliths have been observed (Alcober and Jordan, 1997;Young et al 1998;Sprengel and Young 2000). As with the Alisphaeraceae the hypothesis of independent origin of calcification in the haploid phase allows tentative placement in the phylogenetic tree.…”

Section: Ceratolithaceaementioning

confidence: 99%

“…From molecular data only the Isochrysidales belong in the stem group, and this is a robust result supported by data from 18S, tufA and Rubisco genes (Edvardsen et al 2000;Fujiwara et al, 2001;Saez et al 2004). However, the Ceratolithaceae and the Alisphaeraceae are known, from combination coccosphere evidence, to produce both heterococcoliths and nannoliths within their life-cycle (Alcober and Jordan 1997;Sprengel and Young 2000;Cros et al 2000;Cros and Fortuno 2002;. Young and Henriksen (2003) argue that repeated transfer of calcification from the diploid to the haploid phase of the life-cycle is more likely than transformation of holococcoliths into nannoliths.…”

Section: Notes On Particular Pointsmentioning

confidence: 99%

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A review of selected aspects of coccolithophore biology with implications for paleobiodiversity estimation

2005

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ABSTRACT:To help understand potential biases in coccolithophore paleo-biodiversity estimates various aspects of their biology are reviewed based on the recent monographic guide to extant coccolithophore taxonomy and research developed within the CODENET project. The evidence for life-cycles in coccolithophores involving two biomineralized phases is reviewed in detail, and it is shown that these are likely to have been pervasive through the fossil record of coccolithophores. The extent of polymorphism in extant coccolithophores is reviewed and a surprisingly strong correlation with phylogeny is documented, in particular it is shown that there is a very strong correlation between polymorphism in heterococcolith and holococcolith-bearing phases. Recent documentation of (pseudo)cryptic speciation in coccolithophores is discussed and it is argued that this provides considerable support for the rather fine morphological taxonomy adopted by nannofossil paleontologists, but also means that accurate recognition of species in the fossil record is an almost impossible goal. Finally the diversity of extant coccolithophores is compared with that recorded in Holocene sediments and it is shown that the majority of extant diversity is represented by small rare species with very low preservation potential. It is argued that this is the most serious potential biasing mechanism for study of paleobiodiversity changes since estimates of diversity at any time will be strongly influenced by the availability of well-preserved shelf sediments and of the intensity of their study by electron microscopy. Moreover, secular changes in coccolith size in relation to environmental change could significantly affect the preserved diversity of coccolithophores.

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Section: Ceratolithaceaementioning

confidence: 99%

Section: Notes On Particular Pointsmentioning

confidence: 99%

A review of selected aspects of coccolithophore biology with implications for paleobiodiversity estimation

2005

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“…11), i.e., a phase that produces calcareous structures which do not show the characteristic features of either holococcoliths or heterococcoliths (Young et al 1999). These examples are (1) Ceratolithus, in which a heterococcolith-producing phase alternates with a phase producing large horseshoe-shaped nannoliths (Alcober and Jordan 1997;Young et al 1998;Cros et al 2000;Sprengel and Young 2000). (2) Alisphaera, in which a heterococcolith-producing phase (Fig.…”

Section: The Evolution Of Coccolithophore Biomineralization Mechanismsmentioning

confidence: 99%

Biomineralization Within Vesicles: The Calcite of Coccoliths

Young

2003

Reviews in Mineralogy and Geochemistry

169

122

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“…In the coccolithophores, different life stages are typically more clearly differentiated. In recent years an increasing number of 'combination coccospheres' bearing both heterococcoliths and holococcoliths, interpreted as capturing the instant of a life cycle phase change, have been documented in field samples from various locations (Thomsen etal., 1991;Kleijne, 1992;Alcober& Jordan, 1997;Young etal., 1998;Cros etal., 2000;Cortes & Bollmann, 2002;Geisen etal., 2002, Cros & Fortuno, 2002. In a few cases chromosome counting or DNA quantification by flow cytometry has confirmed the haplo-diploid nature of these cycles: Pleurochrysis carterae (Braarud & Fagerland) Christensen (Rayns, 1962), Hymenomonas lacuna Pienaar (Fresnel, 1994), Emiliania huxleyi (Lohmann) Hay & Mohler (Green etal., 1996).…”

Section: Introductionmentioning

confidence: 99%

Holococcolithophore‐heterococcolithophore (Haptophyta) life cycles: Flow cytometric analysis of relative ploidy levels

Houdan¹,

Billard

Marie

et al. 2004

Systematics and Biodiversity

106

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Several coccolithophore species are known to exhibit heteromorphic life cycles. In certain species, notably Emiliania huxleyi, the heterococcolithbearing phase alternates with a non-calcifying stage, whereas in others the heterococcolith-bearing phase alternates with a holococcolith-bearing phase. Heterococcolithophore-holococcolithophore life cycles have previously been observed for only one species in culture, but have also been inferred from an increasing number of observations of combination coccospheres. 18S rDNA sequences from pure cultures of both the heterococcolith-bearing and holococcolith-bearing phases of Coccolithus pelagicus were identical, providing an additional indication of their identity as different life cycle stages of the same species. Flow cytometric analyses have been undertaken on SybrGreen-stained nuclei isolated from pure cultures of the two phases of four coccolithophore species (Coccolithus pelagicus, Calcidiscus leptoporus, Coronosphaera mediterranea and Emiliania huxleyi) in order to determine relative DNA content. Results confirm the hypothesis that holococcolithophoreheterococcolithophore life cycles are haplo-diploid in nature. Light microscope observations of the processes of sexual fusion and meiosis are reported for two of the experimental species. The results are discussed in the context of the evolution of biomineralization in the coccolithophores and the possible ubiquity of haplo-diploidy in the haptophytes.

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An interesting association between Neosphaera coccolithomorpha and Ceratolithus cristatus (Haptophyta)

Cited by 7 publications

References 0 publications

A review of selected aspects of coccolithophore biology with implications for paleobiodiversity estimation

A review of selected aspects of coccolithophore biology with implications for paleobiodiversity estimation

Biomineralization Within Vesicles: The Calcite of Coccoliths

Holococcolithophore‐heterococcolithophore (Haptophyta) life cycles: Flow cytometric analysis of relative ploidy levels

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