Ascidian spicules of Quaternary sediments from the lower slope of the Campos Basin (Brazil)

Ferreira, Elizabete P.; Alves, Cleber Fernandes; Sanjinés, Antonio Enrique Sayão; Alves, Mariana Cunha

doi:10.1016/j.quaint.2018.11.008

Cited by 4 publications

(7 citation statements)

References 39 publications

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“…Ferreira et al () report similar results from Quaternary sediments in the Campos Basin (Brazil). This site shows low percentages of ascidian spicules in the nannofossil assemblages dominated by Florosphaera profunda , Gephyrocapsa oceanica , and Emiliania huxleyi was interpreted as having been transported from shelf to slope areas during periods of relative sea‐level fluctuations in response to climate variations.…”

Section: Micropaleontologymentioning

confidence: 61%

“…This site shows low percentages of ascidian spicules in the nannofossil assemblages dominated by Florosphaera profunda , Gephyrocapsa oceanica , and Emiliania huxleyi was interpreted as having been transported from shelf to slope areas during periods of relative sea‐level fluctuations in response to climate variations. The correlation between the low concentration of ascidian spicule and sedimentary processes indicates the ascidian spicule transport (Ferreira et al, ). In our case, the dominance of ascidian spicules in the calcareous microfossils assemblage suggests a coastal environment.…”

Section: Micropaleontologymentioning

confidence: 99%

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Calcareous nannofossil biostratigraphy of the External Dinarides flysch (Vrčić‐Staravasa Pag Island, Croatia): A key to an Eocene tectono‐stratigraphic and paleoenvironmental interpretation

et al. 2019

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It is largely accepted that in the Dinaric shallow foredeep basin, the onset of Cenozoic synorogenic sedimentation is diachronous along strike and shows orogenparallel southward younging, creating a large uncertainty in the age of the Dalmatian flysch. Calcareous nannofossil biostratigraphy was studied to investigate a turbiditic succession exposed in Pag Island (Croatia) with the main purpose of constraining its age, which is still a matter of debate. The age assignment for the turbiditic deposition bears important implications for better understanding of the geodynamic and paleoenvironmental evolution of the External Dinarides.We logged a well-exposed sedimentary section in the south-western limb of the Pag anticline and performed calcareous nannofossil quantitative analyses revealing a high species diversity and abundant assemblage. The age diagnostic species indicate CNE14-CNE15 biozones, suggesting that flysch deposition occurred in the Lutetian-Bartonian. This age can be further restricted to the CNE14 (42.37-40.51 Ma) by means of the lowest occurrence of Reticulofenestra reticulata and the highest occurrence of Sphenolithus furcatolithoides. Vertical facies variation and paleoecological indications suggest an increase in paleobathymetric depth during deposition. Our data support a post-Lutetian age of folding and thrusting for the Pag Island region and suggest a relatively short time span during the middle-late Eocene period for the main contractional stage in this sector of the External Dinarides. This result has important implications for the evolution of the Dinaride foreland basin system in Cenozoic times. K E Y W O R D S calcareous nannofossils, Dalmatian flysch, Eocene, External Dinarides, Pag anticline

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Section: Micropaleontologymentioning

confidence: 61%

Section: Micropaleontologymentioning

confidence: 99%

Calcareous nannofossil biostratigraphy of the External Dinarides flysch (Vrčić‐Staravasa Pag Island, Croatia): A key to an Eocene tectono‐stratigraphic and paleoenvironmental interpretation

et al. 2019

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“…Ascidians have several forms of spicules in their bodies, and their geographic variation in morphology makes it difficult to clearly identify ascidian species from their spicules. However, according to previous reports [20][21][22]33,34] the four types of ascidian spicules found in the stomach contents of Z. aeneus could be classified into two genera (Lissoclinum and Trididemnum). It is relevant to note that toxic ascidians have been reported; STXs were found in Microcosmus vulgaris and Holocynthia roretzi, and STXs and TTX in Phallusia nigra [35][36][37].…”

Section: Discussionmentioning

confidence: 99%

Geographic Variations in the Toxin Profile of the Xanthid Crab Zosimus aeneus in a Single Reef on Ishigaki Island, Okinawa, Japan

et al. 2021

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Toxic crabs of the family Xanthidae contain saxitoxins (STXs) and/or tetrodotoxin (TTX), but the toxin ratio differs depending on their habitat. In the present study, to clarify within reef variations in the toxin profile of xanthid crabs, we collected specimens of the toxic xanthid crab Zosimus aeneus and their sampling location within a single reef (Yoshihara reef) on Ishigaki Island, Okinawa Prefecture, Japan, in 2018 and 2019. The STXs/TTX content within the appendages and viscera or stomach contents of each specimen was determined by instrumental analyses. Our findings revealed the existence of three zones in Yoshihara reef; one in which many individuals accumulate extremely high concentrations of STXs (northwestern part of the reef; NW zone), another in which individuals generally have small amounts of TTX but little STXs (central part of the reef; CTR zone), and a third in which individuals generally exhibit intermediate characteristics (southeastern part of the reef; SE zone). Furthermore, light microscopic observations of the stomach contents of crab specimens collected from the NW and CTR zones revealed that ascidian spicules of the genus Lissoclinum were dominant in the NW zone, whereas those of the genus Trididemnum were dominant in the CTR zone. Although the toxicity of these ascidians is unknown, Lissoclinum ascidians are considered good candidate source organisms of STXs harbored by toxic xanthid crabs.

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“…2016; Ferreira et al . 2019). In addition to depth sensitivity, the occurrence of fossil didemnid spicules in the Rhaetian (Fig.…”

Section: Discussionmentioning

confidence: 99%

On the occurrence of rare nannoliths (calcareous nannofossils) in the Early Jurassic and their implications for the end‐Triassic mass extinction

Paulsen

Thibault

2023

Papers in Palaeontology

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A peculiar record of previously undescribed and/ or rarely described nannoliths from the Hettangian to lower Pliensbachian of the Llanbdr (Mochras Farm) core, Wales (UK) is documented here. Some of the observed morphotypes are assigned to didemnid ascidians, commonly observed in the upper Rhaetian, as evidence of the resilience of ascidian tunicates during the end-Triassic mass extinction. One newly described nannolith present throughout the Hettangian and Sinemurian, Quadrifolium hesselboi, is similar to forms previously observed in the upper Rhaetian, and is therefore considered to be a new nannofossil survivor from the end-Triassic mass extinction. High-amplitude changes observed in the absolute and relative abundances of nannoliths, schizosphaerellids and coccoliths across the Hettangian suggest a recovery interval from the end-Triassic crisis spanning the planorbis-liasicus ammonite zones in four distinct steps with high volatility in environmental conditions, followed by the establishment of more stable environmental conditions in the angulata ammonite zone.

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Ascidian spicules of Quaternary sediments from the lower slope of the Campos Basin (Brazil)

Cited by 4 publications

References 39 publications

Calcareous nannofossil biostratigraphy of the External Dinarides flysch (Vrčić‐Staravasa Pag Island, Croatia): A key to an Eocene tectono‐stratigraphic and paleoenvironmental interpretation

Calcareous nannofossil biostratigraphy of the External Dinarides flysch (Vrčić‐Staravasa Pag Island, Croatia): A key to an Eocene tectono‐stratigraphic and paleoenvironmental interpretation

Geographic Variations in the Toxin Profile of the Xanthid Crab Zosimus aeneus in a Single Reef on Ishigaki Island, Okinawa, Japan

On the occurrence of rare nannoliths (calcareous nannofossils) in the Early Jurassic and their implications for the end‐Triassic mass extinction

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