THE GEN. COMELICANIA FRECH, 1901 (BRACHIOPODA) FROM THE SOUTHERN ALPS: MORPHOLOGY AND CLASSIFICATION

Analysis of the internal characters, especially the cardinalia and brachidium, of the brachiopod Comelicania Frech from the Southern Alps, confirmed the attribution of this genus to the Superfam. Athyridoidea Davidson and provided a more complete taxonomic description of the Fam. Comelicaniidae Merla. This family includes two genera which differ in the morphology of their cardinalia, i.e. Gruntallina Waterhouse & Gupta, type-species Gruntallina triangularis (Grunt) from the lower Dorashamian of Transcaucasia and Comelicania, type-species Comelicania megalotis (Stache) from the uppermost Bellerophon Fm. of the Southern Alps. The study of a collection composed of more than a hundred specimens highlighted a broad variability of the morphological characters and a pattern of ontogenetic development which demonstrates that classification at the species level is possible only when using mature specimens. Taxonomic revision at the specific level reduced the eleven species of Comelicania from the Southern Alps, described by previous authors, to: C. megalotis (Stache) and C. haueri (Stache). In addition a new species, C. merlai, which characterises the upper Comelicania beds, is proposed.&nbsp

SYSTEMATICS OF LINGULIDE BRACHIOPODS FROM THE END-PERMIAN MASS EXTINCTION INTERVAL

The systematics of lingulide brachiopods, from the end-Permian mass extinction interval, is here studied and discussed. The material has been collected from upper Permian (Changhsingian) beds of Southern Alps and Lower Triassic beds of several Tethyan localities, where the surviving phase following the peak the end-Permian mass extinction is recorded. The study contributes to fill the gap of knowledge regarding the lingulide systematics during a time lapse crucial for the fate of the Mesozoic and Cenozoic marine organisms. The systematics is based both on inner shell morphology and shell microstructure, which are considered to be the most useful taxonomical characters to study the lingulide phylogeny. The specimens have been referred to species of the new genus Trentingula, which is characterized by a shell with a secondary layer virgose fabric and a primitive disposition of the ventral muscle umbonal scar in the Lingulidae phylogeny. Trentingula n. gen. comprises four species: T. lorigae n. gen. n. sp., type-species, T. borealis (Bittner), T. mazzinensis n. gen. n. sp., and T. prinothi n. gen. n. sp. The type-species is late Griesbachian – Dienerian in age and has a wide geographic distribution in the western Tethys (Southern Alps and Hungary). Trentingula prinothi n. gen. n. sp. occurs in the Upper Permian Bellerophon Formation of the Dolomites; it has a large shell with a short mantle cavity. Trentingula mazzinensis n. gen. n. sp. occurs in the Griesbachian Mazzin Member of Werfen Formation and is characterized by a small sized shell, about half of the type species, which records the “Lilliput effect” related to the aftermath of the end-Permian mass extinction.  &nbsp

Bivalves from the Changhsingian (upper Permian) Bellerophon Formation of the Dolomites (Italy): ancestors of Lower Triassic post-extinction benthic communities

Diverse shallow marine fossil assemblages from the Changhsingian Bellerophon Formation (Dolomites) record late Palaeozoic marine life immediately before the end-Permian mass extinction. We classified c. 6500 bivalves from western Dolomites localities, identifying 26 species including one new family (Ladinomyidae), three new genera (Ladinomya, Lovaralucina, Gardenapecten) and 10 new species: Acharax frenademezi, Bakevellia (Bakevellia) preromangica, Edmondia hautmanni, Etheripecten stuflesseri, Ladinomya fosteri, Lovaralucina covidi, Palaeolima badiotica, Promytilus merlai, Tambanella? stetteneckensis and Volsellina carinata. The occurrence of three Eumorphotis species with different stratigraphic distributions, leads us to propose an upper Permian ‘Lower Eumorphotis Zone’, divided into E. praecurrens, E. striatocostata and E. lorigae subzones, and distinct from the existing Lower Triassic Eumorphotis Zone (here renamed ‘Upper Eumorphotis Zone’). Palaeoecological analysis produced six biofacies and four ecofacies, based on richness, dominance and ecological lifestyle. The bivalves inhabited lagoonal to nearshore environments affected by stressed conditions: high temperatures, high salinity, shallow water depths, low oxygen and high terrigenous input. The upper Bellerophon Fm is characterized by increasingly fully marine conditions, although eurytopic taxa still suggest stressed conditions. Bivalve richness of the upper Permian Bellerophon and Lower Triassic Werfen formations was compared to estimate the genus-level extinction rate. The disappearance of almost half (47%) of Bellerophon Fm genera is remarkably low compared with other, coeval bivalve faunas. Pre-extinction bivalve faunas were dominated by stress-adapted taxa (Unionites, Eumorphotis, Bakevellia, Towapteria) able to thrive in extreme environmental conditions, survive the end-Permian mass extinction, and become the dominant biotic component of Lower Triassic benthic communities globally

AN INSIGHT INTO THE SYSTEMATICS OF PLICATOSTYLIDAE (BIVALVIA), WITH A DESCRIPTION OF PACHYGERVILLIA ANGUILLAENSIS N. GEN. N. SP. FROM THE LITHIOTIS FACIES (LOWER JURASSIC) OF ITALY

The Lithiotis facies represents an Early Jurassic global bioevent characterized by a remarkable spread of gregarious bivalves, which produced large sedimentary bodies in tropical shallow-water marine environments. The most peculiar and common genera Lithiotis, Cochlearites and Lithioperna, with aberrant and extremely elongated or strongly flattened shells, have been studied since the second half of the nineteenth century. Despite numerous systematic studies, their phylogenetic relationship with the other bivalve families is still uncertain. The Lithiotis facies yields other bivalve genera, among which a large multivincular mytiloid, provisionally determined as Isognomon (Mytiloperna) sp. ind. or Mytiloperna sp., is recorded in the literature. This taxon is here studied from a systematic point of view to clarify its taxonomic position and solve the open nomenclature adopted in the past. Here, we propose a new genus Pachygervillia and a new species Pachygervillia anguillaensis. The stratotype is located in the lower part of the Rotzo Formation (Calcari Grigi Group, Lower Jurassic), while the type locality is in the Lessini Mountains (Verona Province, Trento Platform, Southern Alps). This new species is characterized by a thick aragonitic inner shell layer with a fibrous, irregular, spherulitic, prismatic microstructure combined with a nacreous middle layer, both also occurring in species of the genera Lithiotis and Cochlearites of the family Plicatostylidae. This microstructural layering is here proposed as the main taxonomic character of the family, which is here emended and divided into the following two subfamilies: Plicatostylinae, yielding Lithiotis and Cochlearites with stick-like shells, and Pachygervilliinae nov. subfam., yielding Gervilleioperna, Lithioperna, Pachygervillia n. gen., and Pachyperna, previously placed within the subfamily Isognomoninae.

FIRST REPORT OF CLARAIA (BIVALVIA) IN THE SERVINO FORMATION (LOWER TRIASSIC) OF THE WESTERN OROBIC ALPS, ITALY

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Réponse à Didier Fassin

L’argumentation de mon collègue Didier Fassin s’attache dans le détail à dire que Le déni des cultures est un travail « scientifiquement infondé », elle ne propose pas une ligne d’interprétation alternative. Je vais aborder les remarques sur la cohérence puis j’essaierai de montrer que, au-delà des points de méthode et d’analyse statistique, c’est l’ensemble de ma démarche qui a peut-être été mal comprise par l’auteur. Ce que suggèrent aussi quelques citations tronquées. [Premier paragraphe

LATE TRIASSIC MEGALODONTIDAE FROM NORTHERN CALABRIA (ITALY)

Several shells of megalodontids have been extracted from densely packed  coquinas coming from the Upper Triassic of northern  Calabria (Southern Italy). Such a mode of preservation, which is unusual for these bivalves,  has made it possible to detect the morphological characters regarding both the shell and inner mould. Morphological variability has been identified by means of biometrical analysis, which allows them to be separated into two morpho-groups both belonging to the genus Triadomegalodon. Here they are considered to be the extreme morphotypes of a single species, which has some peculiar characteristics with respect to the known species. However, the bad state of the preservation of the shells, which are affected by disarticulation, abrasion and fragmentation, induces us to act  with caution establishing a new taxon [Triadomegalodon sp. n. aff. tofanae  (Hörnes)]. Some aspects of functional morphology led us to consider Triadomegalodon as a semi-infaunal bivalve, unable to burrow actively

FOREWORD. PROCEEDINGS OF THE 8TH INTERNATIONAL BRACHIOPOD CONGRESS BRACHIOPODS IN A CHANGING PLANET: FROM THE PAST TO THE FUTURE, MILANO, 10-14 SEPTEMBER 2018

The 8th International Brachiopod Congress took place in the prestigious venue of the Univer¬sity of Milano, Italy, in September 2018, after the previous edition held in Nanjing, China, in 2015. 150 participants from universities and re¬search institutes from all over the world attended the meeting, from Argentina, Armenia, Austria, Belgium, Canada, China, Czech Republic, Den¬mark, France, Germany, Hungary, Iran, Israel, It¬aly, Japan, New Zealand, Poland, Russia, Slovakia, Spain, Sweden, United Kingdom, and United States of America. Besides oral and poster scientific sessions, pico-presentations of young researchers, and two prestigious plenary lectures, the Congress was preceded and followed by three field trips (Spain, United Kingdom and Sicily), and by two mid-con¬gress day excursions at Castell’Arquato and Grigna Mountains. During the congress, all the topics and the re¬cent advances in the study of brachiopods, marine invertebrates that have dominated the Palaeozoic seas and had an important role in the Phaneorozo¬ic benthic communities, have been touched: from systematics and evolution to biostratigraphy, pala¬eoecology, palaeobiogeography, mass extinctions, and the biology of recent taxa. One of the novelties of this edition was a session dedicated to brachio¬pod shells as biomineral archives of fundamental importance to understand the evolution of marine calcifiers during climate and environmental changes in recent and deep time. So, also biomineralization and geochemistry were among the topics of the event. The high scientific level, activity and wide and interdisciplinary interests of the brachiopod re¬searchers’ community are testified by the numerous contributions received for the Proceedings of the 8th International Brachiopod Congress, 16 of which are published open access in issue 125/3 of Rivista Italiana di Paleontologia e Stratigrafia

Paleoecology and proliferation of the bivalve Chondrodonta joannae (Choffat) in the upper Cenomanian (Upper Cretaceous) Adriatic Carbonate Platform of Istria (Croatia)

Chondrodonta joannae (Choffat) is a morphologically variable oyster-like bivalve with a predominately calcitic shell. An exceptional exposure of C. joannae-bearing strata of late Cenomanian age crops out along the seaside in northern Istria (Croatia) and permits a taphonomical and functional analysis in order to define the life habit and growth strategies of this bivalve. The C. joannae population from the studied succession is characterized by highly-elongated, large and curved shells, reaching about 50 cm in height and 5 cm in length. This shell shape is typical of the club-like bivalve morphotype, which was adapted to soft-bottom substrates with high sediment accumulation. The shell is slightly inequivalve and characterized by a reduced body cavity, a few centimetres high, and a dorsal region up to 10 times longer. The shell opening mechanism was mostly based on the resilium located between the chondrophores which protrude in the body cavity. The abandoned dorsal cavity is filled by a calcite hinge plate, the ventral edge of which acted as fulcrum for the valve flexibility. In the hinge plate, the function of chondrophores changed. They acted as a hinge to keep tightly interlocked the valves, which considerably emerged above the sediment-water interface. The individuals were arranged in low shrub-type congregations, which produced low-relief mounds. The functional morphology and taphonomic signature suggest that C. joannae individuals collected food at a greater distance from the bottom with respect to the co-occurring rudists. We speculate that the C. joannae proliferation could be related to a late Cenomanian phase of environmental instability predating the OAE2 with fluctuating climatic conditions and ocean fertility