RIVISTA ITALIANA DI PALEONTOLOGIA E STRATIGRAFIA

FIRST REPORT ON THE UPPERMOST PERMIAN OSTRACODS FROM THE MASORE SECTION (EXTERNAL DINARIDES), SLOVENIA

2023-11-20T07:31:23+00:00

The ostracod assemblages from the Upper Permian and Permian-Triassic transitional strata of the Masore section in the External Dinarides (Slovenia) were studied. Altogether 13 genera and 20 species of the orders Palaeocopida, Platycopida and Podocopida are identified and illustrated. All recovered ostracods belong to shallow marine taxa. The older fauna from the uppermost Permian and the younger fauna from the Permian-Triassic boundary strata are distinguished. The obtained fauna from the Permian Bellerophon Formation corresponds to the “benthonic ostracod Eifelian Mega-assemblage” occupying the shelf sea floors. This study presents the first report of ostracod faunas from the uppermost Permian and Permian-Triassic boundary interval of Slovenia. The recovered ostracod fauna display a distinct faunal change and yield important paleobiogeographic implications as it reveals similarity with stratigraphical equivalent faunas from some other neighboring localities in the western Paleotethys, such as Bulla in Italy, Komirić in Serbia, and the Bükk Mountains in Hungary.

REVISITING THE CRETACEOUS LUNGFISH ATLANTOCERATODUS IHERINGI (AMEGHINO 1898) FROM THE MATA AMARILLA FORMATION (ARGENTINA) WITH COMMENTS ON TOOTH PLATES HISTOLOGY

2024-02-15T13:03:38+00:00

Atlantoceratodus iheringi (Ameghino 1898) from Argentine territory is restudied based on its known tooth plates and newly discovered material, which includes previously unknown skull roof bones and vomerine tooth plates. The latter represent the first records of such elements from the Mesozoic era in South America. The comparative morphological analysis reveals its distinctiveness from other dipnoans, and offers valuable data for future systematic and phylogenetic research. The pterygopalatine tooth plates display narrow-based first denticulations and lack anterior wear facets, with the inner angle positioned at the level of the second denticulation. Similarly, the prearticular tooth plates feature straight mediolingual edges, and a wide-based first denticulation without sinuosities at the tip. Histological sections are performed and analyzed in detail for the first time. A. iheringi presents in this aspect distinctive features such as: large-lumen denteons tending to cluster together, circumdenteonal dentine arranged in a double band (an inner birefringent and an outer monorefringent), and a disordered interdenteonal dentine, with birefringence surrounding denteons and areas with monorefringence. A. iheringi exhibits histological structure closer to Mesozoic and Cenozoic dipnoans than Paleozoic, especially resembling the disposition observed in the Upper Cretaceous Patagonian species Metaceratodus baibianorum. The wide distribution of features designated as diagnostic for Atlantoceratodus is discussed.

NEW ACROPOMATIFORM FOSSILS FROM THE UPPER KUEICHULIN FORMATION (LOWER PLIOCENE), NORTHERN TAIWAN

2024-03-09T10:37:58+00:00

The Indo-West Pacific is home to a diverse array of modern fish species, and the study of their fossils can provide valuable insights into the origins and evolution of this biodiversity. This report presents rare remains of five individuals of acropomatiform fish, including a semi-articulated skeleton, recovered from the Upper Kueichulin Formation (Lower Pliocene) in northern Taiwan. The fossils are preserved in the form of nodules discovered at the locality known for abundant marine crustaceans and echinoderms. These specimens can be assigned to the family Stereolepididae, based on morphology of the opercle with the presence of two spines, a preopercle characterized by serrations on the posterior margin and denticulations on the ventral margin, and a distinctive skull architecture. Differences in skull morphology distinguish these specimens from other species within the genus and thus are described as Stereolepis arcanum n. sp. Significantly, the species represents the oldest known record of the family globally and stands as the second known fossil representative. This discovery not only enhances our understanding of the palaeobiodiversity of fish fauna in the Indo-West Pacific during the Neogene, but also highlights the importance of further research efforts in this area.

PENNSYLVANIAN CONODONTS AND MICROFACIES FROM NORTHEASTERN MEXICO (TAMATÁN GROUP, CIUDAD VICTORIA BLOCK)

2024-06-18T12:28:26+00:00

The biostratigraphic analysis of the Paleozoic sedimentary successions in Mexico is crucial for understanding their age, depositional setting, and paleogeographic implications. This study examined conodonts and microfacies of calcareous strata within the Del Monte Formation of the Tamatán Group in northeastern Mexico.

Field observations have led to the identification of three units within the Del Monte Formation: Unit 1, characterized by calcareous sandstone, bioclastic limestone, shale, occasional conglomerate, and dolomitized beds; Unit 2, consisting of conglomerate and/or breccia associated with debris flows; and Unit 3 including turbiditic sandstone and shale.

Conodonts were only recognized in Unit 1, with such genera as Idiognathoides, Neognathodus, Idiognathodus and less frequently, Streptognathodus, Adetognathus, and Diplognathodus. The faunal associations include Idiognathoides cf. Id. corrugatus Harris & Hollingsworth, 1933, Idiognathoides sulcatus sulcatus Higgins & Bouckaert, 1968, Idiognathoides convexus (Ellison & Graves, 1941), Idiognathoides asiaticus Nigmadganov & Nemyrovskaya, 1992, Neognathodus cf. N. atokaensis Grayson, 1984, Neognathodus aff. bothrops Merrill, 1972, Neognathodus nataliae Alekseev & Gerelzezeg, 2001 (in Alekseev & Goreva 2001), Streptognathodus parvus Dunn, 1966, Idiognathodus incurvus Dunn, 1966, and Idiognathodus aff. delicatus Gunnell, 1931, suggesting Morrowan and Atokan (Pennsylvanian) ages for the dolomitic limestone and grainstone beds.

Five types of microfacies (MF) and several marine facies zone (FZ) have been detected: MF1-bioclastic grainstone and MF2-wackestone deposited at the platform margin (FZ 6 and FZ 7), MF3-dolomitized wackestone representing an inner restricted platform (FZ 8), MF4-mudstone from a deeper water zone (FZ 4), and MF5-siliciclastic beds with bioclasts indicating a high-energy barrier associated with a platform margin (FZ 6). The findings confirm a shallow to deep platform and imply a connection among Mexican peri-Gondwanan basins, including the Tamatán Basin, indicating similarities in sedimentary facies and/or depositional environments linked to the Rheic Ocean during the Early to Middle Pennsylvanian.

NEW INSIGHTS ON THE ENIGMATIC OTTERS FROM THE LATE MIOCENE OF TUSCANY: TYRRHENOLUTRA MAREMMANA NOV. COMB. (LUTRINAE, MUSTELIDAE, CARNIVORA), WITH A PHYLOGENY OF BUNODONT OTTERS

2024-06-18T12:28:09+00:00

Otters, subfamily Lutrinae (Mustelidae), are predators that thrive in aquatic environments, and have a semiaquatic to fully aquatic lifestyle. While modern otters are found across the globe, their fossil history is limited, primarily documented by fragmented dentognathic remains. In this work, we report on and describe new dental remains of a medium-sized Lutrinae from the Late Miocene of Baccinello and Casteani (Tuscany), improving the poor fossil record of the subfamily in Europe. Tyrrhenolutra helbingi Hürzeler, 1987 is a poorly known species, described on some dental remains from the Baccinello mines and a few other localities. Considering its peculiar morphology, it has often been overlooked in the scientific literature. Description of the material stored at the Naturhistorisches Museum, Basel and Museo di Geologia e Paleontologia dell’Università di Firenze offers new insights on the intraspecific variability and dental morphology of this taxon. The comparative study of these findings highlights several morphological and biometrical similarities between T. helbingi and Paludolutra maremmana Hürzeler, 1987, which allow us to redefine these taxa as Tyrrhenolutra maremmana nov. comb. We carried out a total-evidence cladistic analysis seeking support for morphometric and morphological similarities between T. “helbingi” and “P.” maremmana. The resulting parsimony analyses support the synonymy, excluding a close relationship of T. maremmana with Paludolutra of Italy and Spain, as previously thought. Furthermore, we confirm a long-forgotten hypothesis identifying Limnonyx Crusafont Pairó, 1950 as the possible continental ancestor of Tyrrhenolutra.

THE FIRST RECORD OF THE ORECTOLOBIFORM SHARK GENUS CEDERSTROEMIA (ELASMOBRANCHII, ORECTOLOBIDAE) IN ASIA (KASHIMA FORMATION, UPPER CRETACEOUS; OYUBARI AREA, HOKKAIDO, JAPAN)

2024-03-27T11:13:02+00:00

We described fossil teeth assigned to the orectolobiform shark genus, Cederstroemia collected from the tuffaceous sandstone of the Kashima Formation (Santonian) in the Oyubari area, Hokkaido, Japan. This is the first report of fossil remains of Cederstroemia from Asia. Due to the small number of specimens and their poor preservation, we left the studied material in open nomenclature as Cederstroemia sp. At the same time, the studied material may belong to a new previously undescribed morphology of Cederstroemia. The occurrence of Cederstroemia fossils in Japan indicates that this genus dispersed to the northwestern part of the Pacific Ocean in the Late Cretaceous, which considerably extends the range and previously known habitat of this genus.

AN UNEXPECTED SHORT TOOTH REPLACEMENT CYCLE PERIOD IN MARESAURUS COCCAI (PLESIOSAURIA; RHOMALEOSAURIDAE) FROM THE BAJOCIAN OF ARGENTINEAN PATAGONIA

2024-06-18T12:27:47+00:00

The Rhomaleosauridae were a clade of Jurassic plesiosaurians, characterized by triangular skulls, elongated preorbital region, marked premaxillary-maxillary constriction, and intermediate body proportions between pliosauromorphs and plesiosauromorphs. Despite recent progress in the study of dental replacement in plesiosaurians, the replacement features in rhomaleosaurids have not been studied. Here, the dental features of the rhomaleosaurid Maresaurus coccai are described and analyzed based on the holotype specimen. Regarding symmetry, it was determined that M. coccai shows symmetrical replacement in the maxillary-premaxillary and asymmetrical replacement in the dentary. Additionally, the tooth replacement cycle period (TRCP) of two alveoli was determined for the dental series, with the exception of the anterior part of the left mandibular ramus, which presents an TRCP of three, an asymmetry considered here as teratology. This result indicates that the replacement cycle period (TRCP) of the two alveoli would correspond to a primitive character for Plesiosauria, observing an increase of TRCP from two to three alveoli in taxa comparatively more derived within Pliosauridae.

DIGITAL INVESTIGATION OF LAMNIFORM SHARK VERTEBRAE FROM THE SIBILLINI MTS. (NORTHERN APENNINES, ITALY)

2024-04-18T10:21:42+00:00

During the sampling of a stratigraphic section along the shore of the Fiastra Lake (Carg Project - Sheet 313 “Camerino” of the Geological Map of Italy at 1:50 000 scale), a small rock boulder with partially exposed bony material was discovered at the base of a small cliff at the northern termination of the Sibillini Mts. In this area, the classical facies of Umbria-Marche stratigraphic succession are well exposed. The Oligocene-Miocene portion of the succession is represented by the ~200 m-thick Scaglia Cinerea Formation, passing upwards to the ~100 m-thick Bisciaro Formation. The microfossil assemblage has allowed the specimen to be constrained to the lower Burdigalian. The skeletal remains were examined using a CT-SCAN, a non-invasive method that has proven to be highly performing. The analysis revealed some articulated vertebrae, deformed by lithostatic compaction, which are attributed to a shark of the Order Lamniformes. Subsequently, the vertebrae were digitally isolated, extracted from the surrounding matrix, and rendered into three-dimensional prints. Through digital retro-deformation, the body length of the lamniform shark was estimated to be approximately 4 metres. Further considerations on the vertebrae allowed us to infer that the studied shark had similarities to either Isurus oxyrinchus Rafinesque, 1810 or Carcharodon carcharias Linnaeus, 1758. The development of a dead-fall microbial community likely facilitated the preservation of the vertebrae. The studied specimen represents the first occurrence of a lamniform shark in the Lower Miocene of the Umbria-Marche Domain and represents one of the very rare recorded occurrences of lamniforms from the Lower Miocene of Italy.

THE CARNIVORAN RECORD FROM THE NEOGENE OF EASTERN ROMANIA

2024-04-05T12:58:52+00:00

The present work deals with the carnivorans found in five Neogene localities in eastern Romania: the Vallesian locality of Păun, the Turolian localities of Pogana 1 and Creţeşti 1, and the Ruscinian localities of Bereşti and Măluşteni. The presented material includes cranial and postcranial specimens, some of which are herein described for the first time. This study includes a re-description and re-depiction of the type material of Lutra rumana Simionescu, 1922 and Promephitis malustenensis Simionescu, 1930, in order to clarify the taxonomic position of these two enigmatic taxa. The carnivoran faunal lists of all five localities are reviewed offering interesting insights into the temporospatial range of the discovered forms. Most localities have only yielded a limited number of species, except from Măluşteni, which shows evidence of at least nine different coexisting forms. Notable occurrences in terms of biostratigraphy include Paludolutra sp. in Pogana 1, Protictitherium crassum (Depéret, 1892) in Creţeşti 1, and a phocid from Măluşteni. This review aims to aid the understanding of the Neogene ecosystems in the north of the Paratethys in terms of faunal contents, biostratigraphy and palaeoecology.