Rivista Italiana Di Paleontologia E Stratigrafia最新文献

{"title":"RECONSTRUCTION OF THE MULTIELEMENT APPARATUS OF THE CONODONT GLADIGONDOLELLA TETHYDIS (HUCKRIEDE) USING MULTIVARIATE STATISTICAL ANALYSIS; IMPLICATIONS FOR TAXONOMY, STRATIGRAPHY, AND EVOLUTION","authors":"M. L. Golding, Ali M. Kiliç","doi":"10.54103/2039-4942/19954","DOIUrl":"https://doi.org/10.54103/2039-4942/19954","url":null,"abstract":"The multielement apparatus of the Spathian (late Early Triassic) to Carnian (early Late Triassic) conodont Gladigondolella tethydis (Huckriede, 1958) is reconstructed here using multivariate statistical analysis to determine the co-occurrence of elements previously assigned to the Gl. tethydis apparatus by other authors. Disagreements on the apparatus composition of Gl. tethydis have focussed around whether or not the species contained two pairs of P2 elements, or only one pair. Some reconstructions consider elements referred to Cratognathodus as belonging to the multielement apparatus of Gladigondolella, whereas other workers consider these elements to belong to their own multielement apparatus. In the absence of fused clusters or bedding plane assemblages, multivariate statistical analysis of isolated elements provides the best method for constraining apparatus composition. Examination of collections from the Anisian (early Middle Triassic) of China and Romania, together with published occurrences from the Anisian and Carnian from around the world, has allowed the development of a database for both abundance and presence/absence of elements assigned to the Gladigondolella tethydis apparatus. Bray-Curtis indices for abundance data and Jaccard indices for presence/absence data both demonstrate that Cratognathodus elements occur as frequently with other elements belonging to the Gladigondolella tethydis apparatus as those elements do with each other. This lends support to the hypothesis that Cratognathodus elements also belong to the Gladigondolella tethydis apparatus. Therefore, the Gladigondolella tethydis apparatus proposed herein consists of the following elements: Gladigondolella tethydis (P1); Cratognathodus sp. (P2a): Ozarkodina saginata (Huckriede, 1958) (P2b); Roundya lautissima (Huckriede, 1958) (S0); Lonchodina spengleri (Huckriede, 1958) (S1); an enantiognathid element (S2); Hindeodella petrae-viridis (Huckriede, 1958) (S3); Hindeodella multihamata (Huckriede, 1958) (S4); and Lonchodina venusta (Huckriede, 1958) (M). Several of the elements assigned to the apparatus exhibit morphological variability, including the P1 element of Gladigondolella tethydis.","PeriodicalId":54451,"journal":{"name":"Rivista Italiana Di Paleontologia E Stratigrafia","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139791799","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A NEW MOORISH IDOL (TELEOSTEI, ZANCLIDAE) FROM THE EOCENE OF BOLCA, ITALY","authors":"Giorgio Carnevale, James Tyler","doi":"10.54103/2039-4942/21794","DOIUrl":"https://doi.org/10.54103/2039-4942/21794","url":null,"abstract":"The acanthuriform family Zanclidae, whose members are commonly known as moorish idols, has until now been comprised of two species, the extant Zanclus cornutus and the Eocene Eozanclus brevirostris. Herein, a new moorish idol, Angiolinia mirabilis n. gen. et sp., is described based on three specimens from the Eocene Pesciara site of the Bolca locality, northern Italy.\u0000Morphologically, Angiolinia mirabilis n. gen. et sp. appears to be intermediate between Eozanclus brevirostris and Zanclus cornutus and differs from them by having the following features: body depth 85–87% SL; head length 38.3–39.2% SL; third dorsal-fin spine reaching about 50% SL; pectoral disc width 23.2% SL; dorsal fin containing 31 or 32 rays; anal fin containing 26 or 27 rays; pectoral fin with 11 or 12 moderately elongate rays and caudal fin truncate.\u0000A comparative osteological analysis suggests that the family Zanclidae is defined by two morphological features, namely the presence of a broadly expanded and anteroventrally convex cleithrum forming the so-called pectoral disc together with the coracoid and having a large number of dorsal- and anal-fin rays. The Eocene acanthuriform Massalongius gazolai from Bolca represents the sister group to the Zanclidae. Within the zanclids, Eozanclus brevirostris represents the sister group to the pair formed by Angiolinia mirabilis n. gen. et sp. and Zanclus cornutus. This clade is supported by the shared possession of a single supernumerary spine on the first dorsal-fin pterygiophore, a single uroneural in the caudal skeleton, and all but the first two dorsal-fin spines distally filamentous.","PeriodicalId":54451,"journal":{"name":"Rivista Italiana Di Paleontologia E Stratigrafia","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139852836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"RECONSTRUCTION OF THE MULTIELEMENT APPARATUS OF THE CONODONT GLADIGONDOLELLA TETHYDIS (HUCKRIEDE) USING MULTIVARIATE STATISTICAL ANALYSIS; IMPLICATIONS FOR TAXONOMY, STRATIGRAPHY, AND EVOLUTION","authors":"M. L. Golding, Ali M. Kiliç","doi":"10.54103/2039-4942/19954","DOIUrl":"https://doi.org/10.54103/2039-4942/19954","url":null,"abstract":"The multielement apparatus of the Spathian (late Early Triassic) to Carnian (early Late Triassic) conodont Gladigondolella tethydis (Huckriede, 1958) is reconstructed here using multivariate statistical analysis to determine the co-occurrence of elements previously assigned to the Gl. tethydis apparatus by other authors. Disagreements on the apparatus composition of Gl. tethydis have focussed around whether or not the species contained two pairs of P2 elements, or only one pair. Some reconstructions consider elements referred to Cratognathodus as belonging to the multielement apparatus of Gladigondolella, whereas other workers consider these elements to belong to their own multielement apparatus. In the absence of fused clusters or bedding plane assemblages, multivariate statistical analysis of isolated elements provides the best method for constraining apparatus composition. Examination of collections from the Anisian (early Middle Triassic) of China and Romania, together with published occurrences from the Anisian and Carnian from around the world, has allowed the development of a database for both abundance and presence/absence of elements assigned to the Gladigondolella tethydis apparatus. Bray-Curtis indices for abundance data and Jaccard indices for presence/absence data both demonstrate that Cratognathodus elements occur as frequently with other elements belonging to the Gladigondolella tethydis apparatus as those elements do with each other. This lends support to the hypothesis that Cratognathodus elements also belong to the Gladigondolella tethydis apparatus. Therefore, the Gladigondolella tethydis apparatus proposed herein consists of the following elements: Gladigondolella tethydis (P1); Cratognathodus sp. (P2a): Ozarkodina saginata (Huckriede, 1958) (P2b); Roundya lautissima (Huckriede, 1958) (S0); Lonchodina spengleri (Huckriede, 1958) (S1); an enantiognathid element (S2); Hindeodella petrae-viridis (Huckriede, 1958) (S3); Hindeodella multihamata (Huckriede, 1958) (S4); and Lonchodina venusta (Huckriede, 1958) (M). Several of the elements assigned to the apparatus exhibit morphological variability, including the P1 element of Gladigondolella tethydis.","PeriodicalId":54451,"journal":{"name":"Rivista Italiana Di Paleontologia E Stratigrafia","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139851609","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A NEW MOORISH IDOL (TELEOSTEI, ZANCLIDAE) FROM THE EOCENE OF BOLCA, ITALY","authors":"Giorgio Carnevale, James Tyler","doi":"10.54103/2039-4942/21794","DOIUrl":"https://doi.org/10.54103/2039-4942/21794","url":null,"abstract":"The acanthuriform family Zanclidae, whose members are commonly known as moorish idols, has until now been comprised of two species, the extant Zanclus cornutus and the Eocene Eozanclus brevirostris. Herein, a new moorish idol, Angiolinia mirabilis n. gen. et sp., is described based on three specimens from the Eocene Pesciara site of the Bolca locality, northern Italy.\u0000Morphologically, Angiolinia mirabilis n. gen. et sp. appears to be intermediate between Eozanclus brevirostris and Zanclus cornutus and differs from them by having the following features: body depth 85–87% SL; head length 38.3–39.2% SL; third dorsal-fin spine reaching about 50% SL; pectoral disc width 23.2% SL; dorsal fin containing 31 or 32 rays; anal fin containing 26 or 27 rays; pectoral fin with 11 or 12 moderately elongate rays and caudal fin truncate.\u0000A comparative osteological analysis suggests that the family Zanclidae is defined by two morphological features, namely the presence of a broadly expanded and anteroventrally convex cleithrum forming the so-called pectoral disc together with the coracoid and having a large number of dorsal- and anal-fin rays. The Eocene acanthuriform Massalongius gazolai from Bolca represents the sister group to the Zanclidae. Within the zanclids, Eozanclus brevirostris represents the sister group to the pair formed by Angiolinia mirabilis n. gen. et sp. and Zanclus cornutus. This clade is supported by the shared possession of a single supernumerary spine on the first dorsal-fin pterygiophore, a single uroneural in the caudal skeleton, and all but the first two dorsal-fin spines distally filamentous.","PeriodicalId":54451,"journal":{"name":"Rivista Italiana Di Paleontologia E Stratigrafia","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2024-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139793102","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"FIRST JURASSIC EVIDENCE OF A POSSIBLE SPINOSAURID PEDAL UNGUAL, FROM THE JAISALMER BASIN, INDIA","authors":"ARCHANA SHARMA, FERNANDO E. NOVAS, SANJAY SINGH","doi":"10.54103/2039-4942/20032","DOIUrl":"https://doi.org/10.54103/2039-4942/20032","url":null,"abstract":"We describe an isolated, almost complete pedal ungual phalanx from the Middle Jurassic marine carbonate rocks of the Jaisalmer Basin, Rajasthan, north-western India. The ungual bone is triangular shaped, pointed, elongated, asymmetrical, dorsoventrally compressed, ventrally flat, bearing a shallow semi-circular excavation, and almost straight in lateral view. The morphological features, as well as its proportions closely resemble the pedal ungual phalanges of spinosaurid theropods, presently known dominantly from the Cretaceous. The affinity to spinosaurids is supported by bivariate and multivariate analyses. The ungual phalanx is tentatively identified as a basally branching Jurassic spinosaurid under Megalosauroidea. Considering the stratigraphical and geographical provenances, this contribution may represent the oldest record of a spinosaurid.","PeriodicalId":54451,"journal":{"name":"Rivista Italiana Di Paleontologia E Stratigrafia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136317332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"THE MIDDLE EOCENE CLIMATIC OPTIMUM (MECO) IMPACT ON THE BENTHIC AND PLANKTIC FORAMINIFERAL RESILIENCE FROM A SHALLOW-WATER SEDIMENTARY RECORD","authors":"ANTONELLA GANDOLFI, VICTOR MANUEL GIRALDO-GÓMEZ, VALERIA LUCIANI, MICHELE PIAZZA, THIERRY ADATTE, LUCA ARENA, BRAHIMSAMBA BOMOU, ELIANA FORNACIARI, GIANLUCA FRIJIA, LÁSZLÓ KOCSIS, ANTONINO BRIGUGLIO","doi":"10.54103/2039-4942/20154","DOIUrl":"https://doi.org/10.54103/2039-4942/20154","url":null,"abstract":"We present here new quantitative analyses of planktic and benthic foraminifera to assess the impact of the Middle Eocene Climatic Optimum (MECO, ~40 Ma) on these biotic groups studied along a shallow-water succession rich in larger benthic foraminifera (Sealza, Liguria, NW Italy). The MECO is one of the major Eocene global warming events, characterized by ~4–6°C warming, shifts in the global carbon cycle, and rise in atmospheric pCO2. The Sealza succession is interpreted as the product of a drowning ramp influenced by tectonic activity and provides an exceptional chance to compare biotic variations in shallow-water assemblages with deep-water communities across the MECO. In the section, the MECO interval is tentatively constrained by stable isotope oxygen data and calcareous plankton biostratigraphy. The marked decline in abundance of the epifaunal benthic Cibicidoides across the lower-middle part of the MECO suggests a decrease in oxygenation at the seafloor. Further evidence of oxygen depletion is the increase in organic matter content (TOC) of the sediment and the presence of infaunal genera Uvigerina and Bolivina. The planktic foraminiferal assemblages record the MECO warming in the upper water column as the mixed-layer warm index genera Acarinina and Morozovelloides markedly increase in abundance. In the post-MECO interval, here poorly exposed, cooler conditions are indicated by the dominance of the cold-water index genus Subbotina. Remarkably, Acarinina decline in abundance in the upper MECO interval and never recover. The MECO perturbance permanently impacted the benthic and planktic communities at Sealza that exceeded the tipping point to move to a new regime, thus proving the fauna to be not resilient, but also not recording any extinctions.","PeriodicalId":54451,"journal":{"name":"Rivista Italiana Di Paleontologia E Stratigrafia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135995510","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"BIOSTRATIGRAPHY AND PALEOENVIRONMENTAL ANALYSIS OF THE LOWER MIOCENE QOM FORMATION (JAAM AREA, CENTRAL IRANIAN BASIN)","authors":"BOTOND LÁZÁR, MOSTAFA FALAHATGAR, MEHDI SARFI, MĂDĂLINA-ELENA KALLANXHI, RAMONA BĂLC, LÓRÁND SILYE","doi":"10.54103/2039-4942/18651","DOIUrl":"https://doi.org/10.54103/2039-4942/18651","url":null,"abstract":"Lower Miocene sediments from a previously not investigated outcrop of the Qom Formation (Central Iranian Basin) were studied for their foraminiferal and calcareous nannofossil content. The studied stratigraphic record is assigned to the upper part of calcareous nannofossil NN2 Zone/CN1c Subzone and to the benthic foraminiferal Borelis melo melo Zone of Burdigalian age. The diversity indices, benthic foraminiferal morphogroups, and quantitative analyses of assemblages (principal component and cluster analysis) suggest an overall shallow-marine depositional environment. This interpretation is well constrained based on the dominance of the B1 benthic foraminifera morphotype with biconvex, trochospiral calcareous test, and epifaunal habitat. The identified six cluster groups of benthic foraminiferal assemblages are confirmed by the principal component analysis too, and their distribution along the studied section argue for dynamic changes of the environment. This is well exemplified by a more or less constant shallowing, then deepening trend of the environment as revealed by the shifting from the high diversity, shallow-shelf assemblages of Cluster 5 and 6 toward the low diversity, near-shore Ammonia tepida and Porosononion subgranosus assemblage (Cluster 1), and back.","PeriodicalId":54451,"journal":{"name":"Rivista Italiana Di Paleontologia E Stratigrafia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136143111","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EOCENE RHAMPHOSIDAE (TELEOSTEI: SYNGNATHIFORMES) FROM THE BOLCA LAGERSTÄTTE, ITALY","authors":"PIETRO CALZONI, JACOPO AMALFITANO, LUCA GIUSBERTI, GIUSEPPE MARRAMÀ, GIORGIO CARNEVALE","doi":"10.54103/2039-4942/20707","DOIUrl":"https://doi.org/10.54103/2039-4942/20707","url":null,"abstract":"The Rhamphosidae is an extinct family of syngnathiform fishes from the lower Eocene deposits of Europe, primarily known from specimens derived from the Ypresian Konservat-Lagerstätte of Bolca (Verona province, Italy). A descriptive analysis of 28 specimens of Rhamphosus from Bolca revealed the existence of six species, showing a greater taxonomic diversity compared to the previous scenario of only two species (the type species Rhamphosus rastrum and Rhamphosus biserratus). Four new species are established herein: Rhamphosus bloti n. sp., characterized by a peculiar and unique rostrum with a discoid shape; Rhamphosus brevirostris n. sp., which exhibits a moderately large size associated with a relatively short rostrum; Rhamphosus longispinatus n. sp., characterized by having the longest dorsal-fin spine and rostrum of all the Rhamphosus species; Rhamphosus tubulirostris n. sp., which shows a peculiar slim rostrum, long-based dorsal and anal fins, and a unique squamation characterized by the presence of numerous bucklers. The species from Bolca are also compared to the only other known Rhamphosus species, Rhamphosus rosenkrantzi, from the Fur Formation, Denmark. A number of morphological features support the assignment of the Rhamphosidae to the syngnathiform clade Dactylopteroidei, together with the extant families Dactylopteridae and Pegasidae, representing the sister group to the Pegasidae.","PeriodicalId":54451,"journal":{"name":"Rivista Italiana Di Paleontologia E Stratigrafia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135740660","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"AN INSIGHT INTO THE SYSTEMATICS OF PLICATOSTYLIDAE (BIVALVIA), WITH A DESCRIPTION OF <em>PACHYGERVILLIA ANGUILLAENSIS</em> N. GEN. N. SP. FROM THE <em>LITHIOTIS</em> FACIES (LOWER JURASSIC) OF ITALY","authors":"RENATO POSENATO, GAIA CRIPPA","doi":"10.54103/2039-4942/20273","DOIUrl":"https://doi.org/10.54103/2039-4942/20273","url":null,"abstract":"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.","PeriodicalId":54451,"journal":{"name":"Rivista Italiana Di Paleontologia E Stratigrafia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135736409","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SIDELINED SEASHELLS: REAPPRAISAL OF THE MIDDLE TRIASSIC AMMONOIDS OF SAMOBOR AND ŽUMBERAK MTS. (NORTH-WESTERN CROATIA) AND THEIR SYSTEMATICS AND BIOSTRATIGRAPHIC IMPLICATIONS","authors":"Fran Vidaković, Robert Šamarija, J. Sremac, Dražen Japundžić","doi":"10.54103/2039-4942/19942","DOIUrl":"https://doi.org/10.54103/2039-4942/19942","url":null,"abstract":"Basinal Middle Triassic successions of the Samobor and Žumberak Mts. (north-western Croatia) have historically produced fossils of ammonoids. These finds have, however, largely been neglected in the later literature. This paper describes and redescribes a large collection of ammonoids, most of which were collected by previous researchers throughout the 20th century. Aside from the detailed taxonomic descriptions and revisions, several taxa previously unknown from these localities were identified. Of the species whose holotypes were designated at the Gregruć Breg locality, some are found to be dubious, with validity of other remaining inconclusive and a single taxon, Eoprotrachyceras dorae comb. nov., being treated as valid. Certain Middle Triassic ammonoid genera may also require future comprehensive revisions. A preliminary, modified ammonoid zonal/sub-zonal scheme for the Ladinian of the Tethyan province is proposed, to be inclusive of most of the data from the literature. The need for improvement of the subdivision of this stage is recognized. Based on ammonoids, condensed red nodular limestones of the Gregurić Breg locality (Samobor Mts.) most likely span the Avisianum subzone (upper Illyrian) – Longobardicum subzone (“middle” Longobardian), indicating that subsidence began in the earlier part of the Illyrian. At Mt. Žumberak, scant ammonoid remains indicate that the upper, limestone-rich portion of this succession spans at least the Avisianum subzone (upper Illyrian) – Longobardicum subzone (“middle” Longobardian), but additional data is needed for drawing more robust conclusions. Overall, the timing of basinal deposition is well correlated between Gregurić Breg and Žumberak localities (lower Illyrian – upper Longobardian). ","PeriodicalId":54451,"journal":{"name":"Rivista Italiana Di Paleontologia E Stratigrafia","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41384114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}