RIVISTA ITALIANA DI PALEONTOLOGIA E STRATIGRAFIA

RECONSTRUCTION OF THE MULTIELEMENT APPARATUS OF THE CONODONT GLADIGONDOLELLA TETHYDIS (HUCKRIEDE) USING MULTIVARIATE STATISTICAL ANALYSIS; IMPLICATIONS FOR TAXONOMY, STRATIGRAPHY, AND EVOLUTION

2023-05-08T17:00:10+00:00

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.

A NEW MOORISH IDOL (TELEOSTEI, ZANCLIDAE) FROM THE EOCENE OF BOLCA, ITALY

2024-01-23T14:02:04+00:00

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.

Morphologically, 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.

A 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.

REWORKED MESOZOIC RADIOLARIANS IN MIOCENE-PLIOCENE FORELAND SEDIMENTS IN THE ZAGROS BELT, IRAN

2023-12-18T09:13:46+00:00

Micropaleontology can give important insights into the provenance and paleoenvironmental conditions in terrestrial sedimentary archives. For the current study, 84 samples representing a 2.6 km thick sedimentary profile from the SimplyFolded Zagros Mountain Belt were investigated. They span ca. 10.2 my from the late Middle Miocene (Serravallian) to the earliest Pleistocene (Gelasian), and comprised floodplain sediments and saline mudstones with an aeolian contribution. The mudstones revealed a unique Cretaceous radiolarian assemblage comprising largely of cryptothoracic Nassellarians and spherical spumellarians. This record highlights the reworking of sediments derived from Cretaceous Qulqula- Kermanshah radiolarian claystones and radiolarites in the Imbricated Zagros belt into the distal Neogene Zagros foreland sediments in Lurestan (Lurestan Arc). The high abundance of Holocryptocanium barbui (Dumitrica) and other cryptothoracic taxa compared to the Qulqula- Kermanshah radiolarian claystones and radiolarites potentially indicates a preferred erosion of softer units such as the Red Radiolarian Claystone Unit (RRCU) compared to harder radiolarian cherts. The observation of a reworked largely cryptothoracic assemblage might also point to additional sorting effects during fluvial and aeolian transport as well as during redeposition, depending on the morphology and hydrodynamic properties of individual radiolarian taxa.

REMAINS OF THE ALIMENTARY TRACT IN THE LATE ORDOVICIAN TRILOBITE DALMANITINA (PRAGUE BASIN, BARRANDIAN AREA, CZECH REPUBLIC)

2023-10-31T13:52:41+00:00

Preservation of digestive structures in trilobites is generally rare; remains of the alimentary tract have been documented in about eighty of more than twenty thousand described species. Several tens of specimens belonging to five Cambrian and nine Ordovician species from the Barrandian area, Czech Republic, have markedly contributed to the knowledge of the trilobite digestive system. Here, we describe seven exceptionally preserved late holaspid trilobite specimens of species of the genus Dalmanitina collected from Upper Ordovician strata of the Barrandian area. All studied specimens are preserved as internal moulds and exhibit a narrow strip-like structure that runs sagitally or sub-sagitally under the axial lobe of the thoracopygon. These strip-like structures are markedly different from scavenger burrows and are interpreted as remains of the alimentary canal. A slightly expanded anterior-most part of the digestive system is preserved in the cephalic shield of six specimens and is interpreted as a remainder of the anterior midgut. A dark area is seen in the glabellar lobes of three specimens. These dark areas do not represent pyrite concentrations in the hypostome–glabellar cavity, because they contain only small amounts of Fe and S. These areas are interpreted as the remainder of cephalic digestive midgut diverticula, or the “perigastric organ”. Quantitative chemical analyses show that in species of Dalmanitina the digestive system is preserved as dark matter containing partly digested food particles and most probably also a higher amount of clay minerals. The described specimens constitute the first well-documented example of digestive structures in the subfamily Dalmanitininae.

NEW FOSSIL LACEWING LARVAE WITH TRUMPET-SHAPED ELONGATE EMPODIA PROVIDE INSIGHT INTO THE EVOLUTION OF THIS ATTACHMENT STRUCTURE

2023-10-24T12:42:42+00:00

The larval life phase often represents the major share of the life span of holometabolans, such as beetles or flies. Therefore, knowledge of these larvae is crucial concerning ecological functions, but also concerning the evolutionary history of the different groups. In the holometabolan group Neuroptera (lacewings), larvae have numerous specialisations, among them the venom-injecting mouthparts, the stylets. Another such very characteristic feature of many lacewing larvae is the empodium, an attachment structure at the tip of the leg, which varies in shape in the larvae of the different lacewing groups. One type of empodium is the elongate trumpet-shaped type, which is found in several lacewing groups today as well as in many fossil representatives, especially well visible due to preservation in amber. Based on the pattern of phylogenetic distribution of the elongate trumpet-shaped empodium, different reconstructions of the evolution of this structure have been put forward, some suggesting possibly convergent evolution, others repetitive losses. In this study, new lacewing larvae preserved in 100-million-year-old amber from Myanmar are presented, which expand the number of lineages with an elongate trumpet-shaped empodium. Based on these new data, the implications on the evolutionary history of the different lineages within Neuroptera are discussed. The fossils demand for an earlier evolution in some reconstructions, but especially for more and later losses of this structure.

FIRST EVIDENCE OF PALAEO-TETHYAN UPPER TRIASSIC CALCAREOUS NANNOFOSSILS IN NORTH DOBROGEAN OROGEN (ROMANIA)

2023-05-17T06:14:51+00:00

This study presents the analysis of Upper Triassic sediments from five locations in North Dobrogea
(Romania) and the Black Sea. Microfacies analyses on thin sections from the Frecăţei log reveal a shallowing trend and likely an increase in energy upward into the section. The oldest part of the log is characterised by deposition of mudstones transitioning to wackestones, with an increase of bivalves. Similar wackestones are observed in the Izvoarele and Rândunica logs, i.e. microfacies with abundant bivalves, some foraminifera and echinoderms. The offshore boreholes 816 and 817 Lebăda Vest (core CM 9 and CM 31) seem to have been deposited in a basinal or distal marine shelf environment indicated by the presence of mudstones with rare bioclasts. In contrast, sample CM 10 from borehole 816 LV is a micritised grainstone suggesting a deposition in a shallower, higher energy environment.
Scanning electron microscope observations reveal a moderate diagenetic alteration in all studied samples, mainly due to dissolution. Two calcareous nannofossil species: Prinsiosphaera triassica triassica and Eoconusphaera zlambachensis were commonly observed in sample F of the Frecăţei log, allowing for assignment of the sediments to the Rhaetian age. Two coccoliths were also observed in sample F of Frecăţei log and sample CM 9 of the borehole 816 LV indicating the presence of coccolithophorids within the study region. This discovery constitutes the first confirmed record of well-preserved, determinable Upper Triassic calcareous nannofossils in the Palaeo-Tethys Ocean.

OF HIS BONES ARE CRINOID MADE: TAPHONOMY AND DEADFALL ECOLOGY OF MARINE REPTILES FROM A PELAGIC SETTING (MIDDLE-UPPER JURASSIC OF NORTHEASTERN ITALY)

2024-01-31T08:30:44+00:00

Modern cetaceans are considered the best anatomical and ecological analogue for many Mesozoic secondary aquatic reptiles. Such similarities extend also after the death of these phylogenetically distant amniotes, when the sinking and decomposition of large carcasses in marine environments (deadfalls) follow common biostratinomic processes. Most taphonomic studies on Mesozoic deadfalls have been limited to shallow-water settings, often neglecting deeper waters. Here we provide a detailed taphonomic survey of ichthyosaurs, pliosaurs and metriorhynchoids from the pelagic Middle-Upper Jurassic Rosso Ammonitico Veronese (RAV) of northeastern Italy. Our taphonomic revision of the RAV tetrapod record highlights a common poor state of preservation of the bones, often associated with abundant macrofossils, consistent with a prolonged exposure of carcasses on a well-oxygenated seafloor. For the first time we confirm the role of nautiloids as active mobile scavengers by means of tens of beak elements found closely associated with, or even piercing, the bones. Hexanchiform shark teeth are also found associated with the carcasses, supporting a distinctive deep-water mobile scavenging community. Echinoids, sponges and other bioeroders are identified as representative of the enrichment-opportunist stage, and a high concentration of belemnites is believed to be indicative of mass-spawning deaths in the surroundings of the carcasses. Abundant crinoids are recognized as part of the reef stage by colonization of the eroded bones. While some of our data deviate from previous Mesozoic reptile-falls from shallow-waters, they are consistent with findings at Recent whale-falls in bathyal zones, and overall represent a precious window into the complex ecology of Jurassic open seas.

NEW REPORT OF DECAPOD AND ISOPOD CRUSTACEANS FROM THE LOWERMIDDLE PLEISTOCENE OF MONTALBANO JONICO, MATERA (BASILICATA, SOUTHERN ITALY)

2023-12-17T15:48:08+00:00

The study of the Lower-Middle Pleistocene decapod crustacean fauna from Montalbano Jonico succession allowed 12 taxa to be recognized. The studied samples include some fossil species already known from the Pleistocene record of Italy, as Ebalia nux A. Milne-Edwards, 1883, Monodaeus bortolottii Delle Cave, 1988, Liocarcinus depurator (Linnaeus, 1758), Goneplax rhomboides (Linnaeus, 1758), and Chlinocephalus demissifrons Ristori, 1886. These species are reported for the first time from Basilicata, except for E. nux, whereas Carcinoplax jonica n. sp. and Neogoneplax bradanica n. sp. are introduced as new species. Moreover, one poorly preserved specimen is assigned to Ebalia sp.; one dubitative specimen to ?Carcinus sp.; one specimen to Bathycalliax sp. (Axiidea de Saint Laurent, 1979); one to an indeterminate galatheid; and two poorly preserved large-sized specimens are tentatively referred to Carcinoplax sp. (Goneplacidae, MacLeay, 1838). Finally, several indeterminate specimens of cirolanid (Isopoda) are reported, as well.
The studied decapod community from Basilicata allows us to expand our knowledge of Pleistocene fossil crabs and their distribution around the Mediterranean Sea basin in the Lower-Middle Pleistocene.

EOCENE STALKED CRINOIDS IN THE GENUS ISSELICRINUS (ECHINODERMATA, CRINOIDEA, ISOCRINIDA) FROM NORTHEASTERN ITALY

2023-11-27T10:57:00+00:00

Long fragments of isocrinid stalks belonging to the stalked crinoid genus Isselicrinus (Isocrinida, Isselicrininae) were found at Cambrigar, near Ferrara di Monte Baldo (Verona province, northeastern Italy) in the strata called “Harpactocarcinus punctulatus and Pentacrinus diaboli horizon”, traditionally ascribed to the lower Eocene (Ypresian). Morphometric analysis of this material allowed us to identify two distinct species filtering their food at different levels of the water column. The first species, characterized by a mostly pentagonal stalk section, is ascribable to Isselicrinus diaboli (Bayan), a taxon frequently cited from the lower Eocene of northeastern Italy but until now poorly known. The other species has a marked star-shaped stalk section presenting a combination of pedomorphic characters and is ascribed to the new taxon Isselicrinus baldoensis n. sp. A detailed analysis of numerous columnals and pluricolumnals of Isselicrinus diaboli from the type-locality of San Pancrazio near Mossano (Berici Hills, Vicenza province, northeastern Italy) allowed us to propose a revised and more complete diagnosis of this taxon. The particular burial conditions and the ecology of these two species are discussed as well as a reappraisal of the age of the “Harpactocarcinus punctulatus and Pentacrinus diaboli horizon”. Based on new calcareous nannofossil data, and confirmed by the larger foraminiferal assemblages, the isocrinids from Cambrigar are firmly assigned to the Lutetian (middle Eocene). Calcareous nannofossils identified in the matrix of historical hand specimens from the classical locality of San Pancrazio indicate a similar age.