Martín De Los Reyes, Carolina Acosta Hospitaleche, María Alejandra Sosa
A tarsometatarsus recovered from the lower Pleistocene levels of the La Esperanza Formation in Olavarría, Argentina, represents the first avian remains reported from this locality. Its morphology and size allow its assignment to Aramides cajaneus (Aves, Gruiformes), a species that still occurs in or near the area. Members of the genus Aramides are terrestrial birds closely associated with wetland environments, providing valuable paleoenvironmental insight into the conditions that prevailed in the region during the Pleistocene.
Abstract The Taiwan waters (western North Pacific) include five sea turtle species without an associated fossil record. Here, we describe the first fossil sea turtle from Taiwan. This fossil material is a partial hypoplastron from the uppermost Yuching Shale in Tainan. The preserved morphology of this partial hypoplastron shows a slightly curved medial margin, a deep lateral notch, and a wide sutural anterior margin, indicating a taxonomic affinity to the genus Caretta. In comparison with extant Caretta, the preserved hypoplastral width at the sutural level (130.85 mm) suggests that this fossil belongs to an old subadult cf. Caretta. In addition, we also analyzed fossil foraminifera from the matrix of this hypoplastron, suggesting that the depositional environment was a continental shelf no more than 100 m deep. We further examined the nannofossils and found more than 200 calcareous nannofossils, including index fossils, such as Pseudoemiliania lacunosa, Helicosphaera sellii, and large Gephyrocapsa sp. (> 5.5 μm), corresponding to NN19a nannofossil biozone (Early Pleistocene in age). Given the first occurrence of the large Gephyrocapsa sp. and the last occurrence of Helicosphaera sellii, we narrowed down the age of this Pleistocene sea turtle from Taiwan to 1.57 to 1.28 million years ago. Our discovery of this Pleistocene sea turtle fossil represents not only the first cheloniid fossil in Taiwan but also the first well-dated fossil sea turtle from the global Pleistocene. The Taiwan waters during the Early Pleistocene may be a paleo-foraging ground for cf. Caretta, and future fieldwork and analysis should reveal a more detailed evolutionary history of sea turtles in the North Pacific. Our results also highlight the potential for more paleontological progress from Taiwan.
Libro de Resúmenes de las IV Jornadas de Paleontología de la Cuenca Neuquina, que tuvo lugar en Malargüe (Mendoza, Argentina) del 27 al 30 de Septiembre del 2023.
Libro de Res´´umenes de la Reunión de Comunicaciones de la Asociación Paleontológica Argentina. La misma tuvo lugar en la Universidad Nacional de Río Negro, en la ciudad de General Roca (Río Negro, Argentina) durante los días 22-24 de Noviembre del 2023.
Kinga Gere, András Lajos Nagy, Torsten M. Scheyer
et al.
Abstract Placodonts were durophagous reptiles of the Triassic seas with robust skulls, jaws, and enlarged, flat, pebble-like teeth. During their evolution, they underwent gradual craniodental changes from the Early Anisian to the Rhaetian, such as a reduction in the number of teeth, an increase in the size of the posterior palatal teeth, an elongation of the premaxilla/rostrum, and a widening of the temporal region. These changes are presumably related to changes in dietary habits, which, we hypothesise, are due to changes in the type and quality of food they consumed. In the present study, the dental wear pattern of a total of nine European Middle to Late Triassic placodont species were investigated using 2D and 3D microwear analyses to demonstrate whether there could have been a dietary shift or grouping among the different species and, whether the possible changes could be correlated with environmental changes affecting their habitats. The 3D analysis shows overlap between species with high variance between values and there is no distinct separation. The 2D analysis has distinguished two main groups. The first is characterised by low number of wear features and high percentage of large pits. The other group have a high feature number, but low percentage of small pits. The 2D analysis showed a correlation between the wear data and the size of the enlarged posterior crushing teeth. Teeth with larger sizes showed less wear feature (with higher pit ratio) but larger individual features. In contrast, the dental wear facet of smaller crushing teeth shows more but smaller wear features (with higher scratch number). This observation may be related to the size of the food consumed, i.e., the wider the crown, the larger food it could crush, producing larger features. Comparison with marine mammals suggests that the dietary preference of Placochelys, Psephoderma and Paraplacodus was not exclusively hard, thick-shelled food. They may have had a more mixed diet, similar to that of modern sea otters. The diet of Henodus may have included plant food, similar to the modern herbivore marine mammals and lizards.
Abstract In comparison to other cephalopods such as ammonites and belemnites, nautilid shells are relatively rare fossils in Jurassic marine deposits and knowledge of their taxonomy is therefore still patchy. We describe herein a new species of Cenoceras, C. rumelangense, from the early Bajocian Humphriesianum Zone of Luxembourg and Southwest Germany. In Luxembourg, the type material occurs in the ‘Marnes sableuses d’Audun-le-Tiche’ unit, which yields other large-sized cephalopods, such as the largest known belemnite genus, Megateuthis. The new species reaches a remarkable size, with diameters up to 610 mm. Thus, it is amongst the largest known post-Triassic nautilids worldwide, together with Paracenoceras giganteum and Paracenoceras ingens from the Upper Jurassic. Additionally, we discuss some aspects of the taphonomy of these large shells deposited in a shallow marine setting. ZooBank LSID: urn:lsid:zoobank.org:pub:376E5DF8-653D-429C-8AD6-835D325D2912
MARCELA CICHOWOLSKI, N. EMILIO VACCARI, ALEXANDER POHLE
et al.
We describe early Tremadocian (Kainella meridionalis Biozone) cephalopods from the Cordillera Oriental, Jujuy, NW
Argentina. They consist of numerous small specimens collected at the Quebrada de Arenal, Trancas section, near the
town of Tilcara, in the Alfarcito Member of the Santa Rosita Formation. All but three specimens were assigned to a new
species of Ellesmeroceras (Family Ellesmeroceratidae), E. humahuacaensis sp. nov., based on its slightly endogastric
curvature, the characteristics of the siphuncle and chambers dimensions. Micro CT scanning of one specimen aided in
the description of the apex and facilitated the construction of a 3D model of the species. A single, similar specimen was
assigned to Ellesmeroceras sp. pending the availability of additional material. Two specimens differ from the rest, being
exogastric with a lower angle of expansion. They are tentatively assigned to Bassleroceras sp. This material indicates
that Cambrian and early Tremadocian cephalopods are not as different as previously thought. “Diversification” and
“extinction” events during the late Cambrian may be attributed to taxonomic “over-splitting” and taphonomic and/or
sampling biases, respectively. These specimens are currently the oldest recorded in the Central Andean Basin and of
West Gondwana, and probably represent the first migration of cephalopods into the region, when the water column was
still poorly colonized. During the middle Tremadocian, subsequent immigrations and originations of several cephalopod
orders accounted for a rise in diversity and expansion into new niches during this interval. Some of these taxa persisted
into the middle Floian, at which time, a second increase in diversity is recorded. Ellesmeroceras humahuacaensis sp.
nov. is interpreted as a sub-vertical nektobenthic organism.
Christophe Ferrante, Heinz Furrer, Rossana Martini
et al.
Abstract Coelacanths form today an impoverished clade of sarcopterygian fishes, which were somewhat more diverse during their evolutionary history, especially in the Triassic. Since the first description of the coelacanth Ticinepomis peyeri from the Besano Formation of the UNESCO World Heritage Site of Monte San Giorgio (Canton Ticino, Switzerland), the diversity of coelacanths in the Middle Triassic of this area of the western Paleo-Tethys has been enriched with discoveries of other fossil materials. At Monte San Giorgio, two specimens of Heptanema paradoxum and several specimens of the unusual coelacanth Rieppelia heinzfurreri, have been reported from the Meride Limestone and the Besano Formation, respectively. Another unusual coelacanth, Foreyia maxkuhni, and two specimens referred to Ticinepomis cf. T. peyeri have been described from the isochronous and paleogeographical close Prosanto Formation at the Ducanfurgga and Strel sites (near Davos, Canton Graubünden). In the framework of the revision of the coelacanth material from the Besano Formation kept in the collection of the Paläontologisches Institut und Museum der Universität Zürich (Switzerland), we reviewed the genus Ticinepomis on the basis of the holotype and four new referred specimens. Several morphological traits that were little and/or not understood in T. peyeri are here clarified. We re-evaluate the taxonomic attribution of the material of Ticinepomis cf. T. peyeri from the Prosanto Formation. Morphological characters are different enough from the type species, T. peyeri, to erect a new species, Ticinepomis ducanensis sp. nov., which is shown to be also present in the Besano Formation of Monte San Giorgio, where it is represented by fragmentary bone elements. The recognition of a new coelacanth species indicates that the diversity of this slow-evolving lineage was particularly high in this part of the Western Tethys during the Middle Triassic, especially between 242 and 240 million years ago.
AbstractThe terminal Ediacaran Shibantan biota (~550–543 Ma) from the Dengying Formation in the Yangtze Gorges area of South China represents one of the rare examples of carbonate-hosted Ediacara-type macrofossil assemblages. In addition to the numerically dominant taxa—the non-biomineralizing tubular fossil Wutubus and discoidal fossils Aspidella and Hiemalora, the Shibantan biota also bears a moderate diversity of frondose fossils, including Pteridinium, Rangea, Arborea, and Charnia. In this paper, we report two species of the rangeomorph genus Charnia, including the type species Charnia masoni Ford, 1958 emend. and Charnia gracilis new species, from the Shibantan biota. Most of the Shibantan Charnia specimens preserve only the petalodium, with a few bearing the holdfast and stem. Despite overall architectural similarities to other Charnia species, the Shibantan specimens of Charnia gracilis n. sp. are distinct in their relatively straight, slender, and more acutely angled first-order branches. They also show evidence that may support a two-stage growth model and a epibenthic sessile lifestyle. Charnia fossils described herein represent one of the youngest occurrences of this genus and extend its paleogeographic and stratigraphic distributions. Our discovery also highlights the notable diversity of the Shibantan biota, which contains examples of a wide range of Ediacaran morphogroups.UUID: http://zoobank.org/837216cd-4a4a-4e13-89e2-ee354ba48a4c
René Hoffmann, Kevin Stevens, Marie-Claire Picollier
et al.
Previously, palaeopathological features of fossil hardparts were often difficult to interpret because it was impossible to decipher their internal structure without destroying the specimens. We applied high-resolution computedtomo graphy (CT) to document such internal structures. This enabled us to describe a variety of pathologies of Jurassic and Cretaceous belemnite rostra. The examined rostra have been assigned to the taxa ?Acrocoelites sp., Belemnello camax spp., Belemnitella sp., Duvalia emerici, Goniocamax sp., Gonioteuthis spp., Hibolithes jaculoides, Neoclavibelus subclavatus, and Pseudobelus sp. The studied pathologies comprise rostra with two apices, bulges, pearls, broken juvenile rostra, highly porous rostra with abnormal growth increments, blunt-rostra, rostra with callus- like structures, and bent- or knee-shaped rostra. In one rostrum the apex has been turned towards the anterior (alveolus) during ontogeny. Additionally, computed-tomography data were used to document diagenetic alterations of the rostra such as silification, sedimentary infill, pyrite formation. Specimens can also be tested for the presence or absence of internal elements (septa, siphuncle) and surface features. Palaeoecological studies clearly benefit from the application of computed-tomography to gain high resolution images of otherwise invisible internal features of extinct organisms, as demonstrated herein.
M. Jimena Franco, Eliana Moya, Mariana Brea
et al.
AbstractThis paper presents new descriptions of Anacardiaceae fossil woods from the Ituzaingó Formation (late Cenozoic) at the Toma Vieja, Curtiembre, and Arroyo El Espinillo localities, Argentina. We describe eight silicified woods assigned to four different species in three genera, one of which,Parametopioxylon crystalliferumn. gen. n. sp., is new. Similarities between these three genera and the six Anacardiaceae species previously recorded from the late Cenozoic in northeastern Argentina are investigated using multivariate analysis techniques (correspondence and cluster analysis). Our study is based on 33 characters scored for 17 fossil specimens (10AstroniumxylonBrea, Aceñolaza, and Zucol 2001; fiveSchinopsixylonLutz, 1979; and twoParametopioxylonn. gen.) and four extant species (Astronium balansaeEngl.,Astronium urundeuvaEngl.,Schinopsis balansaeEngl., andMetopiumsp.). Our main goal is to determine the wood anatomical features useful for distinguishing among these species. Results of the multivariate analyses support the previous classification whereSchinopsixylonis distinguished fromAstroniumxylonby having exclusively paratracheal axial parenchyma, ≥30% multiseriate rays, and multiseriate rays that are ≥5 cells wide and commonly 301–400 μm in height. Additionally, we propose thatSchinopsixylon heckiiLutz, 1979 is synonymous withS.herbstiiLutz, 1979. A diagnostic key for the fossil species studied is given. Wood anatomy of Anacardiaceae fossil woods from Argentina (late Cenozoic) suggests a warm, dry to semi-humid climate for this region, supporting previous studies.
Three new bivalve genera and species are described from Upper Triassic hydrocarbon seep deposits from the Kasımlar shales in the Taurus Mountains in southern Turkey. Terzileria gregaria and Kasimlara kosuni belong to the carditiid family Kalenteridae, and Aksumya krystyni belongs to the anomalodesmatan superfamily Pholadomyoidae. A single specimen is described in open nomenclature as Kasimlara sp. due to its significantly more angular shell profile compared to K. kosuni. The kalenterids Terzileria and Kasimlara narrow the stratigraphic gap between two seep-inhabiting “modiomorphid” clades: the Silurian–Devonian Ataviaconcha and the Late Jurassic–Cretaceous Caspiconcha. This raises the questions whether these four genera are members of a single phylogenetic lineage that continuously inhabited deep-sea hydrocarbon seeps from the Silurian to the Cretaceous (the “single lineage hypothesis”), or are repeated offshoots of various lineages that convergently developed similar morphological adaptations to this habitat (the “repeated colonization hypothesis”). Aksumya represents the first anomalodesmatan genus that appears to be restricted to the seep environment, considering that all previous claims of seep-inhabiting anomalodesmatans are questionable.
Philip J. Currie, Gregory F. Funston, Halszka Osmólska
New specimens of Elmisaurus rarus from the Upper Cretaceous of Mongolia (Nemegt Formation) preserve bones not previously found in “elmisaurids” that help elucidate their relationships to Leptorhynchos elegans and other oviraptorosaurs. Elmisaurus rarus and the North American Leptorhynchos elegans are known from numerous but incomplete specimens that are closely related to, but nevertheless clearly distinguished from, Chirostenotes pergracilis and Epichirostenotes curriei. These specimens include the first known cranial bone attributed to Elmisaurus, the frontal, which clearly shows this animal had a cranial crest (most of which would have been formed by the nasal bones). The first vertebrae, scapula, femora, and tibiae from Elmisaurus are also described. The Elmisaurinae can be distinguished from the Caenagnathinae by the coossification of the tarsometatarsus and smaller size at maturity. Examination of oviraptorosaur hindlimbs reveals four distinct morphotypes, possibly attributable to paleoecological differences.
Maria V. Guler, Melisa A. Paolillo, Paula A. Martz
Abstract. The present work documents and gathers the most relevant records of the organic-walled dinoflagellate cysts from different sites of the Neuquén and Austral Basins. Most of these records have contributed to the palaeoenvironmental, biostratigraphical and palaeobiogeographical interpretations of the different stratigraphical units in both basins. The dinoflagellate cysts assemblages come from the Springhill, Upper Rio Mayer, Piedra Clavada, Kachaike and Margas Verdes Formation of the Austral Basin and, from the upper part of the Vaca Muerta Formation and the Agrio Formation of the Neuquen Basin, several of these stratigraphical units conform the main petroleum systems in both basins.
KEY WORDS. Cretaceous, Marine palynomorphs, Sedimentary basins, Argentina.
Resumen. QUISTES DE DINOFLAGELADOS DEL CRETÁCICO TEMPRANO DE LAS CUENCAS NEUQUINA Y AUSTRAL: BIOESTRATIGRAFÍA Y PALEOBIOGEOGRAFÍA. Se documentaron y recopilaron los registros más relevantes de los quistes de dinoflagelados de pared orgánica provenientes del Cretácico inferior de las cuencas Neuquina y Austral en diferentes localidades de estudio. La mayoría de estos registros han contribuido a las interpretaciones paleoambientales, bioestratigráficas y paleobiogeográficas de diferentes sucesiones sedimentarias marinas en ambas cuencas. Las asociaciones de quistes de dinoflagelados provienen de las Formaciones Springhill, Rio Mayer Superior, Piedra Clavada, Kachaike y “Margas Verdes” de la cuenca Austral y, de la parte superior de la Formación Vaca Muerta y de la Formación Agrio de la cuenca Neuquina, varias de estas unidades estratigráficas conforman los principales sistemas petroleros de ambas cuencas.
PALABRAS CLAVE. Cretácico, Palinomorfos marinos, Cuencas sedimentarias, Argentina.
Five incomplete skeletons of fishes of the extinct monotypic family Polymerichthyidae (Aulopiformes: Alepisauroidei) from the Paleogene and Neogene of Sakhalin Island, Russia, are identified as Polymerichthys sp., described in detail, and compared with known representatives of the family. The results of this study suggest that polymerichthyids were characterized by a prolonged rostrum, behind which the upper jaw symphysis was placed; by an anal fin without spinules, contrary to what was assumed earlier; and, probably, by sexual dimorphism. Morphological analysis reveals the closest relationships of Polymerichthyidae to be with Recent Alepisauridae, but their taxonomic position is still unresolved. The new material is the second occurrence of articulated skeleton of fishes of this family. The new findings from Sakhalin expand the known geographical distribution of Pacific polymerichthyids by about 12° of latitude, and extend the time interval for this family to as early as the late Oligocene.