Middle Triassic (Anisian) Cephalopods From the Mecsek Mountains, Hungary

Abstract

Recent nautiloid and ammonoid finds from the Middle Triassic Zuhánya Limestone Formation in the Mecsek Mountains (south Hungary) proved that the formation encompasses the whole Pelsonian and the lower Illyrian substages of the Anisian Stage. On the basis of 11 identified ammonoid species, the Balatonicus and Trinodosus zones have a complete record. The stratigraphical position of the Zuhánya Limestone on the whole corresponds to the Felsőörs Limestone in the Balaton Highland. The palaeobiogeographical evaluation of the cephalopod fauna showed that the elements of the nautilid fauna point mostly to Germanic and partly to Sephardic affinity. On the other hand, the ammonoid fauna has no Germanic elements; most of the species are Alpine in character, while the species Procladiscites brancoi indicates Dinaridic connection, or at least an occasional appearance of pelagic organisms. These results endorse the previous palaeogeographical assumption and suggest that during the Middle Triassic the Mecsek succession was situated along the European shelf, between the Vindelician-Bohemian Land and the open Tethyan Ocean.

Monospecific mass occurrence of a new species of the Early Jurassic genus Arzonellina (Brachiopoda) at Fenyveskút (Bakony Mountains, Hungary)

“…various brachiopod communities. Due to the extensional tectonic movements (see VÖRÖS & GALÁCZ 1998), fissures opened from time to time on the rocky bottom. The fissures received, or even sucked in, the shells available near the opening of the fissure.…”

“…Repeated tectonic movements along the fault scarp occurred in the Sinemurian, late Pliensbachian, and twice in the Bajo cian. The matrix of the mega-breccia cannot be directly observed but it is very probable that the youngest sediment (i. e. the upper Bajocian brachiopodal limestone) forms the matrix, which sets the age of the latest phase of breccia formation in the late Bajocian (GALÁCZ 1988, VÖRÖS & GALÁCZ 1998) (Figure 2).…”

Latest Triassic and Early Jurassic Spiriferinida (Brachiopoda) of Zealandia(New Zealand and New Caledonia)

“…Vörös et al (2016) discussed this further, pointing out that the two remaining spire-bearing orders (Spiriferinida and Athyridida) had only a muted recovery after the end-Triassic crisis, and did not survive the Toarcian crisis. Vörös et al (2019) suggest that this may have been due to the restrictions the calcareous spiralia impose on the lophophore of these groups, in contrast to the less constrained lophophore of the terebratulides and rhynchonellides. This had previously been suggested by Ager (1987).…”

“…The Zealandian occurrences range from middle Hettangian to Toarcian (see Appendix 1). Vörös et al (2019) suggest that by the Toarcian the spiriferinides were geographically restricted to the Western Tethys, apart from "a single occurrence in New Zealand" (p. 718). Barnes et al (2021) show that "dead clades walking" are a pervasive and complex macroevolutionary pattern.…”

Linking Western Tethyan Rhynchonellide morphogroups to the key post-Palaeozoic extinction and turnover events

“…Representatives of phylum Brachiopoda are frequently used in macroevolutionary studies (e.g. Ager 1956a;Johnson 1975;McNamara 1982;Ager 1983;Raup 1986;Valentine and Jablonski 2010;Carlson 2016;Stigall 2018) due to their wide-ranging record throughout the Phanerozoic, their considerable diversity and abundance, and relatively simple body plan, endowing this group with a reasonable morphological stability range (Kowalewski et al 1997;Krause 2004;Harper et al 2017;Topper et al 2017;Vörös et al 2019). Owing to their close connection with substrata and short mainly lecithotrophic larval stage (at least in post-Palaeozoic times), they are also exceptional proxies to shed light on the response of marine benthic ecosystems to environmental perturbations.…”