Taxonomy and palaeoecology of the Early Jurassic (Pliensbachian) bivalves from Buttenheim, Franconia (Southern Germany)

Karapunar, Baran; Werner, Winfried; Fürsich, Franz T.; Nützel, Alexander

doi:10.1127/pala/2020/0098

Cited by 6 publications

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“…In the clay pit of Buttenheim, this species is part of a diverse bivalve fauna of altogether 57 species (Karapunar et al . 2020). It is interpreted as one of the oldest representatives of the family Thyasiridae that is known for a chemosymbiotic life habit (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…The bivalve collection studied comprises approximately 7,000 bivalve specimens from the clay pit near Buttenheim (Karapunar et al . 2020). Of them, 77 specimens have been assigned to the species Eothyasira antiqua (Münster in Goldfuss, 1841) (Karapunar et al .…”

Section: Introductionmentioning

confidence: 99%

“…Of them, 77 specimens have been assigned to the species Eothyasira antiqua (Münster in Goldfuss, 1841) (Karapunar et al . 2020). Eight Eothyasira specimens represent fragments or single valves and are therefore not included in the statistical analyses of the present study.…”

Section: Introductionmentioning

confidence: 99%

“…co‐occurrence and diversity of infaunal and epifaunal taxa, ichnofauna) point to a soft, but not soupy substrate (Karapunar et al . 2020). Thus, the lateral pressure of the sediment on the shell was obviously sufficient enough to prevent the gaping of the valves after death of the bivalve.…”

Section: Introductionmentioning

confidence: 99%

“…Eothyasira specimens have only been found in the uppermost 5–6 m of the Amaltheenton Formation exposed in the Buttenheim clay pit (below and in the echinid–pectinid horizon; Karapunar et al . 2020, text‐fig. 2).…”

Section: Introductionmentioning

confidence: 99%

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Predatory drill holes in the oldest thyasirid bivalve, from the Lower Jurassic of South Germany

Karapunar

Werner

Fürsich

et al. 2021

LET

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Drill holes provide valuable information about palaeoecological interactions in fossil ecosystems, but the Jurassic drill‐hole record is scarce. We report circular drill holes in the infaunal bivalve Eothyasira antiqua(Münster in Goldfuss) from the Pliensbachian grey shales of the Amaltheenton Formation of Franconia, southern Germany. The outcrop of the Amaltheenton Formation at Buttenheim yields a rich bivalve fauna (57 species), which represents a typical soft‐bottom community. Eothyasira antiqua, the yet oldest known member of the family Thyasiridae, represents only 1% of the total bivalve specimens from Buttenheim, but shows an exceptionally high frequency of drill holes. With a drilling rate of 81% of the well‐preserved articulated specimens, this occurence is unique compared with other drilled bivalve records from the Mesozoic and even from Recent assemblages. The drill holes resemble those of modern naticids with a larger outer opening and are assigned to the ichnospecies Oichnus paraboloides Bromley. Statistical methods show a non‐random distribution of the drill holes over the shell surface with a concentration on the central flank. The drill‐hole producer was highly efficient in drilling and exhibited a remarkable prey and site‐selective behaviour. The drill holes on the moderately deep infaunal Eothyasira suggest that the predator was also infaunal for at least parts of its life and could cope with poorly oxygenated substrate conditions occurring temporarily in the Amaltheenton environment. Drill‐hole characteristics point to a gastropod as producer. None of the about 50 gastropod taxa of the Amaltheenton Formation can be associated with the drill holes with certainty, but Hayamia reticulata (Münster) seems to be the most likely candidate. The results of this study support the opinion that drill holes are generally a scarce phenomenon in the Early Jurassic generated by rare, probably highly specialised predators. Preservational biases are considered to have been less important.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Predatory drill holes in the oldest thyasirid bivalve, from the Lower Jurassic of South Germany

Karapunar

Werner

Fürsich

et al. 2021

LET

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Glendonite-bearing concretions from the upper Pliensbachian (Lower Jurassic) of South Germany: indicators for a massive cooling in the European epicontinental sea

Merkel

Munnecke

2023

Facies

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The Pliensbachian–Toarcian transition was characterised by a drastic turnover from a cool climate to a period of rapid global warming. While the warming associated with the Early Toarcian Oceanic Anoxic Event is rather well-studied, the cause, intensity and extent of the preceding cooling in the late Pliensbachian are still discussed. Occurrences of glendonite play an important role in this debate, since glendonite is a pseudomorph after the cryophilic carbonate mineral ikaite. This study describes the first glendonite-bearing carbonate concretions from South Germany (Buttenheim clay pit, northern Franconian Alb), which represent the southernmost glendonite occurrence in the late Pliensbachian documented so far. Based on petrographical and sedimentological investigations as well as stable isotope analyses it is concluded that a low temperature was the main factor for ikaite formation in the studied section, suggesting that the late Pliensbachian cooling had a more far-reaching impact on the temperature of the European epicontinental sea than previously assumed. To explain the low temperatures required for ikaite precipitation, a model for the sea-ice driven formation of cold bottom-water masses on the continental shelf is proposed. The occurrence of several layers containing reworked hiatus concretions in the studied outcrop is interpreted as the result of recurrent sea-level falls caused by multiple glacial pulses characterising the overall cool climate in the late Pliensbachian.

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The earliest example of sexual dimorphism in bivalves—evidence from the astartid Nicaniella (Lower Jurassic, southern Germany)

Karapunar¹,

Werner

Fürsich

et al. 2021

J. Paleontol.

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Protandrous sex change (sex change from male to female) is one of the diverse sexual expressions exhibited by bivalves, but its expression in the shell is quite rare. Previous studies on living and fossil astartids suggest a relationship between protandrous sex change and the formation of crenulations on the ventral shell margin at later ontogenetic stages. Here we report the formation of such crenulations in the Early Jurassic astartid Nicaniella rakoveci (Kuhn, 1935) from the Amaltheenton Formation at Buttenheim, Franconia. This is the earliest known record of protandrous hermaphroditism in fossil bivalves, predating previous reports by at least 13 Myr. A principal component analysis of linear size measurements and Fourier shape analysis of the shell outlines revealed that the outline of Nicaniella rakoveci specimens varies from subquadrate to subcircular, but this variation is independent of the presence or absence of crenulations and therefore not associated with sex. Crenulated specimens exhibit a lower height/inflation ratio than non-crenulated ones, suggesting that the protandrous females have more inflated valves than the males. The formation of crenulations was probably related to allocation of resources for reproduction. The most likely function of the crenulations was to increase the internal shell volume in the female stage to accommodate more eggs rather than being an adaptation against predation as often assumed for other bivalves. The formation of crenulations is part of the protandrous life history and probably is controlled by a genetic mechanism that is also responsible for sex change.

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Taxonomy and palaeoecology of the Early Jurassic (Pliensbachian) bivalves from Buttenheim, Franconia (Southern Germany)

Cited by 6 publications

References 0 publications

Predatory drill holes in the oldest thyasirid bivalve, from the Lower Jurassic of South Germany

Predatory drill holes in the oldest thyasirid bivalve, from the Lower Jurassic of South Germany

Glendonite-bearing concretions from the upper Pliensbachian (Lower Jurassic) of South Germany: indicators for a massive cooling in the European epicontinental sea

The earliest example of sexual dimorphism in bivalves—evidence from the astartid Nicaniella (Lower Jurassic, southern Germany)

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