Early Jurassic Caenogastropoda and Architectibranchia from the Neuquén Basin, Argentina

Blodgett²,

Hodges

et al. 2020

andgeo

Self Cite

A middle Hettangian marine gastropod assemblage is reported from the Kenai Peninsula of south-central Alaska supplying new paleontological evidence of this group in Lower Jurassic rocks of North America. Pleurotomaria pogibshiensis sp. nov. is described from the middle Hettangian marine succession informally known as Pogibshi formation, being the first occurrence of the genus in the Kenai Peninsula and the oldest occurrence of the genus in present-day Alaska and North America. One species of the genus Lithotrochus, namely Lithotrochus humboldtii (von Buch), is also reported for the first time from the Kenai Peninsula. Lithotrochus has been considered as endemic to South America for a time range from the early Sinemurian to the late Pliensbachian. The newest occurrence of Lithotrochus in rocks of the Pogibshi formation extends the paleobiogeographical and chronostratigraphical distribution of the genus into the present-day Northern Hemisphere. However, the Southern Hemisphere affinities are consistent with the hypothetical interpretations (although supported both by paleobiogeographical and paleomagnetic data) that the Peninsular terrane of south-central Alaska is far-traveled and may have originated at much more southerly paleolatitudes than its present-day position. Two other Early Jurassic caenogastropods typical of the Andean region of South America and of the Tethyan epicontinental seas are described for the first time in the Pogibshi formation, and these are Pseudomelania sp. and Pictavia sp. The new gastropod assemblage reported here shows close affinities with coeval South American and European gastropod faunas, supplying new evidence to interpret their distribution during the Early Jurassic.

“…Site JL198, middle Hettangian beds of July member, Pogibshi formation (Coronoides zone), Seldovia, Alaska (Peninsular terrane, southcentral Alaska). Gründel, 2001;Ferrari, 2017).…”

Section: Subclass Caenogastropoda Cox 1960mentioning

confidence: 99%

Early Jurassic (middle Hettangian) marine gastropods from the Pogibshi Formation (Alaska) and their paleobiogeographical significance

Blodgett²,

Hodges

et al. 2020

andgeo

Self Cite

“…More precisely, we considered measurements (height of the shell in mm) of 55 specimens belonging to 18 species from the studied time interval, which have originally been assigned to the genus. Data were taken from the literature [8][9][10][11][12][13][14][15][16][17] and from available data of the MNHN and GBIF online repositories (https://science. mnhn.fr; https://www.gbif.org).…”

Section: Methodsmentioning

confidence: 99%

Gastropods underwent a major taxonomic turnover during the end-Triassic marine mass extinction event

Hautmann²

2022

PLoS ONE

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Based on an exhaustive database of gastropod genera and subgenera during the Triassic–Jurassic transition, origination and extinction percentages and resulting diversity changes are calculated, with a particular focus on the end-Triassic mass extinction event. We show that gastropods suffered a loss of 56% of genera and subgenera during this event, which was higher than the average of marine life (46.8%). Among molluscs, gastropods were more strongly affected than bivalves (43.4%) but less than ammonoids, which were nearly annihilated. However, there were also pronounced differences among gastropod subclasses. The most strongly affected subclass was the Neritimorphia, which lost 72.7% of their Rhaetian genera; on the other extreme, the Heterobranchia remained nearly unaffected (11% loss). We analysed this extinction pattern with respect to larval development, palaeobiogeography, shell size, and anatomy and found that putative feeding of the pelagic larval stage, adaptation to tropical-temperate water temperatures, and flexibility of the mantle attachment were among the factors that might explain extinction resilience of heterobranchs during the end-Triassic crisis. Among molluscs, extinction magnitude roughly correlates with locomotion activity and thus metabolic rates. We suggest three potential kill mechanisms that could account for these observations: global warming, ocean acidification, and extinction of marine plankton. The end-Triassic extinction of gastropods therefore fits to proposed extinction scenarios for this event, which invoke the magmatic activity of the Central Atlantic Magmatic Province as the ultimate cause of death. With respect to gastropods, the effect of the end-Triassic mass extinction was comparable to that of the end-Permian mass extinction. Notably, Heterobranchia was relatively little affected by both events; the extinction resilience of this subclass during times of global environmental changes was therefore possibly a key aspect of their subsequent evolutionary success.

“…9 as Actaeonina transatlantica ; Gründel 2011, p. 65, pl. 6, figs 10, 11; Ferrari 2017, p. 260, fig. 4.15–4.20), from the Lower Jurassic (Pliensbachian) of Argentina resembles S. elegans sp.…”

Section: Systematic Palaeontologymentioning

confidence: 99%

“…1, figs 15–20), from the Middle Jurassic (late Bathonian) of Poland, but the latter species has a slightly weaker and narrower sutural ramp, and the crossing points of the axial and spiral elements are only weakly nodose. R. patagoniensis (Ferrari, 2012) (p. 329, figs 4G–P, 5A–K, as Procerithium (Rhabdocolpus) patagoniensis Ferrari, 2017, p. 6, fig. 2.14–2.17), from the Sinemurian–Toarcian of Argentina, differs from P. quadrilineatum in having a step‐like outline shell with a broader and horizontal sutural ramp, and weaker and less rounded nodes at the crossing points of the axial and spiral elements.…”

Section: Systematic Palaeontologymentioning

confidence: 99%

See 1 more Smart Citation

Upper Toarcian (Lower Jurassic) marine gastropods from the Cleveland Basin, England: systematics, palaeobiogeography and contribution to biotic recovery from the early Toarcian extinction event

Papers in Palaeontology

Little

Atkinson

2020

Self Cite

Here we describe a new upper Toarcian (Lower Jurassic) marine gastropod fauna from rocks of the Cleveland Basin exposed on the North Yorkshire coast of England. The fossil assemblage consists of 16 species, of which three are new: Katosira? bicarinata sp. nov., Turritelloidea stepheni sp. nov. and Striactaenonina elegans sp. nov. Four species are described in open nomenclature as Tricarilda? sp., Jurilda sp., Cylindrobullina sp. and Cossmannina sp. The other species have previously been described: Coelodiscus minutus (Sch€ ubler in Zieten), Procerithium quadrilineatum (R€ omer), Pseudokatosira undulata (Benz in von Zieten), Palaeorissoina aff. acuminata (Gr€ undel), Pietteia unicarinata (Hudleston), Globularia cf. canina (Hudleston), Striactaeonina cf. richterorum Schulbert & N€ utzel, Striactaenonina aff. tenuistriata (Hudleston) and Sulcoactaeon sedgvici (Phillips). Most of these species are the earliest records of their respective genera and show palaeobiogeographical connections with