Two turtles with soft tissue preservation from the platy limestones of Germany provide evidence for marine flipper adaptations in Late Jurassic thalassochelydians

Late Jurassic deposits across Europe have yielded a rich fauna of extinct turtles. Although many of these turtles are recovered from marine deposits, it is unclear which of these taxa are habitually marine and which may be riverine species washed into nearby basins, as adaptations to open marine conditions are yet to be found. Two new fossils from the Late Jurassic of Germany provide unusually strong evidence for open marine adaptations. The first specimen is a partial shell and articulated hind limb from the Late Jurassic (early Tithonian) platy limestones of Schernfeld near Eichstätt, which preserves the integument of the hind limb as an imprint. The skin is fully covered by flat, polygonal scales, which stiffen the pes into a paddle. Although taxonomic attribution is not possible, similarities are apparent with Thalassemys. The second specimen is a large, articulated skeleton with hypertrophied limbs referable to Thalassemys bruntrutana from the Late Jurassic (early Late Kimmeridgian) platy limestone of Wattendorf, near Bamberg. Even though the skin is preserved as a phosphatic film, the scales are not preserved. This specimen can nevertheless be inferred to have had paddles stiffened by scales based on the pose in which they are preserved, the presence of epibionts between the digits, and by full morphological correspondence to the specimen from Schernfeld. An analysis of scalation in extant turtles demonstrated that elongate flippers stiffed by scales are a marine adaptation, in contrast to the elongate but flexible flippers of riverine turtles. Phylogenetic analysis suggests that Thalassemys bruntrutana is referable to the mostly Late Jurassic turtle clade Thalassochelydia. The marine adapted flippers of this taxon therefore evolved convergently with those of later clades of marine turtles. Although thalassochelydian fossils are restricted to Europe, with one notable exception from Argentina, their open marine adaptations combined with the interconnectivity of Jurassic oceans predict that the clade must have been even more wide-spread during that time.

Sponge Takeover from End-Permian Mass Extinction to Early Induan Time: Records in Central Iran Microbial Buildups

The end-Permian mass extinction was the most severe biotic crisis in Earth’s history. In its direct aftermath, microbial communities were abundant on shallow-marine shelves around the Tethys. They colonized the space left vacant after the dramatic decline of skeletal metazoans. The presence of sponges and sponge microbial bioherms has largely gone unnoticed due to the sponges’ size and the cryptic method of preservation. In addition to sponge dominated facies recently described in South Armenia and Northwestern Iran, we describe here sponge-microbial bioherms cropping out in two well-known Permian-Triassic boundary localities: the Kuh-e Hambast section, south-east of Abadeh city and the more distal Shahreza section, near Isfahan. In both sections, the extinction horizon is located at the top of an upper Changhsingian ammonoid-rich nodular limestone, called Paratirolites limestone. At Kuh-e Hambast, the overlying decimetric thick shale deposit called “boundary clay,” the latest Permian in age, is conformably overlain by well-dated transgressive basal Triassic platy limestone containing four successive levels of decimeter to meter scale, elongated to form cup-shaped mounds made of branching columnar stromatolites. Sponge fibers from possibly keratose demosponge, are widely present in the lime mudstone matrix. At the Shahreza section, above the extinction level, the boundary clay is much thicker (3 m), with thin platy limestone intervals, and contains two main levels of decimeter to meter scale mounds of digitate microbialite crossing the Permian-Triassic boundary with similar sponge fibers. Three levels rich in thrombolite domes can be seen in the overlying 20 m platy limestone of earliest Triassic age. Sponge fibers and rare spicules are present in their micritic matrix. These sponge fibers and spicules which are abundant in the latest Permian post-extinction boundary clay, followed microbial buildups during the Griesbachian time.

Botanical curiosities of Prodarjeva Grapa gorge in the upper Bača Valley (western Slovenia) / Botanične posebnosti Prodarjeve grape v zgornji Baški dolini (zahodna Slovenija)

We researched the vegetation of the protected lower part of the Prodarjeva Grapa gorge in the foothills of Mt. Porezen in the upper Bača Valley. Its botanical curiosities are the localities of protected or rare species Moehringia villosa, Pri­mula auricula,Pinguicula vulgarisand Carex frigida. All four occur (but are not limited to) on the rocky and gra­velly shady area in the lower part of the gorge with a distinctly cold local climate. The relief, climate and parent material (platy limestone with admixture of marlstone and chert) are the decisive factors that allow for the occurrence of the previously unknown community of wet spring areas, which we classify into the new association Pinguiculo vul­garis-Cari­cetum frigidae, alliance Cratoneurion commutatiand class Montio-Cardaminetea, in this area. It is syndynamically connected with surrounding communities of wet screes and rock crevices. Screes under the rock wall are partly overgrown with a community of Molinia arundinaceaand Adeno­styles glabra (Adenostylo glabrae-Molinietum arundinaceanom. prov.), on the fringes in places also with an open low-growth hop-hornbeam and manna ash forest (Palustriello commutati-Ostryetum carpinifoliaenom. prov.). Key words: vegetation, synsystematics, Carex frigida, Moehringia villosa, Pinguicula vulgaris, Primula auricula,Bača Valley, Porezen, Natura 2000 Izvleček Raziskali smo rastje spodnjega, zavarovanega dela Prodarjeve grape v prigorju Porezna v zgornji Baški dolini. Njene botanične posebnosti so nahajališča zavarovanih ali redkih vrst: Moehringia villosa, Primula auricula,Pinguicula vulgarisin Carex frigida. Vse štiri med drugim rastejo v skalnatem in gruščnatem osojnem območju v spodnjem delu grape z izrazito hladnim krajevnim podnebjem. Relief, podnebje in geološka podlaga (ploščasti apnenec s primesjo laporovca in roženca) so odločilni dejavniki za tukajšnje uspevanje do zdaj nepoznane rastlinske združbe vlažnih povirij, ki jo uvrščamo v novo asociacijo Pinguiculo vulgaris-Caricetum frigidae,v zvezo Cratoneurion commutatiin v razred Montio-Cardaminetea. Sindinamsko je povezana z okoliškimi združbami vlažnih melišč in skalnih razpok, pri čemer se melišča pod steno deloma zaraščajo z združbo trstikaste stožke – Adenostylo glabrae-Molinietum arundinaceanom. prov., na robovih tudi z vrzelastim nizkim gozdom črnega gabra in malega jesena – Palustriello commutati-Ostryetum carpinifoliaenom. prov. Ključne besede: vegetacija, sinsistematika, Carex frigida, Moehringia villosa, Pinguicula vulgaris, Primula auricula, Baška dolina, Porezen, Natura 2000

Epizoic stramentid cirripedes on ammonites from Late Cretaceous platy limestones in Mexico

The discovery of platy limestone deposits in northeastern Mexico has led to the collection of well-preserved stramentids of early Turonian age from Vallecillo, state of Nuevo León, and of early Coniacian age from El Carranza, state of Coahuila.Stramentum(Stramentum)pulchellum(Sowerby, 1843) colonized the ammonite shells during the lifetime of the animals, occasionally in two subsequent generations. Colonization of the ammonite shell byStramentum(S.)pulchellumwas hindered by strong ornamentation only. The ammonites did not interfere with their epizoans. Colonization during lifetime shows that these ammonites dwelled in well-oxygenated water levels near the surface, and most stramentids were embedded alive. The known paleobiogeographic occurrence ofStramentum(S.)pulchellumand its long stratigraphic occurrence are considerably enlarged by our findings. The pseudoplanktonic mode of life ofStramentum, and attachment to ammonite shells, may have been a response of a once benthic organism to repeated oxygen-deficient conditions on the seafloor of mid-Cretaceous oceans, i.e., to oceanic anoxic events (OAEs).