Abstract A fossil interpreted as a long-legged lobopodian animal (Hallucigenia? sp.) is described from the middle Cambrian (Miaolingian) Jince Formation of the Příbram–Jince Basin (Barrandian area, Czech Republic). The fossil shows a long vermiform trunk, at least twenty-five long thin lobe-like appendages indicating the ventral side, and the bases of at least 12 thin spines protruding dorsally. Palynological processing of fine-grained rock samples from ca. 100 m higher in the section yielded several tens of small carbonaceous fossils attributable to armoured lobopodians alongside wiwaxiid sclerites and additional abundant organic-walled microfossils. The Bohemian specimen and recent finds of rare lobopodians in Australia, China, and the USA, together with many occurrences of isolated spines interpreted as belonging to hallucigeniids, demonstrate that lobopodians were much more geographically widespread than previously thought. The Bohemian macrofossil is the youngest known occurrence of a hallucigeniid; this specimen and the microfossil material extend the stratigraphic range of the group within the traditional early to middle Cambrian interval.
Abstract The present paper describes the latest cephalopod fauna from the Upper Ordovician in the Anti-Atlas region, Morocco. Two species are reported herein belonging to two genera including one new species, Tafadnatoceras elfechtense sp. nov. and Isorthoceras sp.; the latter of which marks the first occurrence of the genus in Morocco. The discovery extends the distribution of late Katian cephalopod faunas globally, correlative with other high-latitude cephalopod faunas such as those from the Zagros region of Iran. After the evolutionary peak of the Great Ordovician Biodiversification Event in the Middle to early Late Ordovician, a marine ecosystem crisis led to a decline in biodiversity afterwards. Although the cephalopods continued to flourish in low-latitude regions, the palaeogeographic differentiation was observed in the Anti-Atlas region, where the faunas in the high-latitude region experienced a significant decline. The pattern aligns with the changes in the latitudinal diversity gradient from the Middle to Late Ordovician. Furthermore, the distributions of the cephalopod faunas in the Late Ordovician may have been influenced by the emergence of the high-latitude cold current.
Claudia Inés Montalvo, Marta Susana Kin, Fernando Julián Fernández
et al.
Neotaphonomic studies of vertebrates provide information about the mechanisms and processes that can modify the original characteristics of skeletal elements and can be used as analogues for interpretations on the origin of archeological and paleontological assemblages. The neotaphonomic evaluation of non-ingested bones (leftover prey remains) and modified digested bones by the crowned eagle (Buteogallus coronatus Accipitriformes, Accipitridae) is presented. Bones were recovered from the nests located in the central–west La Pampa Province, Argentina. Leftover prey remains include representatives of Aves, Iguania, Ophidia, Cingulata, Lagomorpha, and Carnivora. Bones from pellets correspond to Ophidia, Rodentia, and osteoderms of two armadillos Chlamyphoridae (Xenarthra, Cingulata). Some of the latter correspond to pichi (Zaedyus pichiy Euphractinae), a common species that is usually located in the diet of B. coronatus. Zaedyus pichiy osteoderms, recovered from pellets, present modifications in the original ornamentation, as well as a reduction in their thickness. Various pellets also contained remains of pink fairy armadillo (Chlamyphorus truncatus, Chlamyphorinae), a small paradigmatic, nocturnal and fossorial species, endemic to centralwestern Argentina, which is recorded for the first time as part of this raptor diet. This first mention of Chl. truncatus being captured by the crowned eagle is relevant because it involves two little–known and sympatric species, in an area where this armadillo is endemic. Osteoderms of Chl. truncatus show an extreme degree of modification, and it is interpreted that its potential of preservation in the fossil record is very low.
Markus J. Poschmann, Thomas A. Hegna, Lea Numberger-Thuy
et al.
AbstractThe hitherto oldest known mass mortality of clam shrimp is described from the Early Devonian (Emsian) of Luxembourg. This (almost) monospecific clam shrimp association allows for a much more comprehensive assessment and understanding of preservational and ontogenetic variation in a single taxon, Pseudestheria diensti (Gross, 1934). This suggests that other taxa originally described from the “classical” Willwerath locality, the type locality of P. diensti, are variants of the latter, and thus Pseudestheria subcircularis Raymond, 1946 and Palaeolimnadiopsis ? eifelensis Raymond, 1946 are synonymized here with P. diensti. A further clam shrimp taxon, for which we propose a new species, Palaeolimnadia stevenbeckeri n. sp., is found in the same stratum, but not in the mass mortality layer itself. The clam shrimp mass mortality is interpreted to reflect sudden destruction of the original habitat on a delta plain and subsequent transport and burial in a marginal marine low-energy setting.http://zoobank.org/0cfcb6a1-3fb7-4a1a-a1a4-609f8b1bc536
Mirta Elena Quattrocchio, Luis Sebastián Agüero, Ari Iglesias
et al.
This study focuses on the early Paleogene deposits of the southernmost Golfo San Jorge Basin (central Patagonia, Argentina), cropping out at the Laguna Manantiales site. Based on palynological and sedimentological features, a new continental stratigraphic unit, informally named as Laguna Manantiales Strata, is here defined. The sporomorphs recorded evidence of the presence of subtropical forests. The syncolporate pollen grains comparable to those of the modern taxon Senna pendula, are mentioned for the first time in Argentina. Based on the record of Malvacipollis diversus, Bombacacidites isoreticulatus, Cricotriporites guianensis and the similarity in the pollen grains composition, the identified palynological assemblage can be correlated to the Patagonian palynofloras from the late Paleocene–early Eocene Ligorio Márquez Formation and the early Eocene Laguna del Hunco site. Thus, the proposed age for the Laguna Manantiales Strata can be constrained between the late Paleocene and the early Eocene. The records of Huanilipollis cabrerae, H. crisci, and Mutisiapollis sp. in Laguna Manantiales Strata, confirm the early development for Mutisioideae for the early Paleogene in Patagonia. The pronounced climatic warming during the late Paleocene and the early Eocene influenced the diversification of Asteraceae in Patagonia.
Mercedes Fernández, Mariano Bond, Juan Carlos Fernicola
In 1903, Florentino Ameghino erected the genus and species Caenophilus tripartitus based on a mandibular fragment and a lower isolated molar. The former specimen was illustrated about a decade later and it has been considered missing since, at least, 1986. The first review of the species was carried out in 2019, in which the authors presented new materials from Cerro Zeballos (Chubut Province) assigned to this taxon, a new specific description, and a discussion regarding the provenance of the type specimen, due to the contradictions perceived by them in the Ameghino’s papers. Recently, the holotype of Caenophilus tripartitus was located within the Colección Nacional Ameghino at the Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”. In this contribution, we present the first study of this holotype in more than a century, concluding that it did not come from the area of Río Fénix and Laguna Blanca, Mayo Formation, but from an uncertain stratigraphic level at the area of Colhué-Huapí, Chubut Province (Argentina). In addition, the comparison with the material from Cerro Zeballos evidences that it is not referable to C. tripartitus and would represent a second species of the genus, Caenophilus zeballensis sp. nov. In this way, the biochron of C. tripartitus is unknown, whereas that of the genus goes back at least to the late Middle Miocene (Serravallian).
Abstract The fossil collections made by early explorers in South America have been fundamental to reveal the past diversity of extinct mammals and unravel their evolutionary history. One important early explorer in South America was the Swiss-Argentine palaeontologist Kaspar Jacob Roth, known as Santiago Roth (1850, Herisau, Switzerland-1924, Buenos Aires, Argentina), who made significant collections of fossil mammals that are housed in museums in Europe and Argentina. The important collections of Roth in Switzerland include iconic Pleistocene megafauna from the Pampean Region (Argentina). The palaeontological significance of the Pampean Region relies on its abundant record of fossil vertebrates that documents diversity dynamics and paleoenvironmental change in southern South America, serving as the basis for the South American biostratigraphical scale of the late Neogene and Quaternary. The South American native ungulates (SANUs) were hoofed placental mammals that radiated in South America. The clades Notoungulata and Litopterna include, among others, the last representatives of SANUs megafauna in the continent. We revise and describe for the first time the SANUs specimens from the Pampean Region of the Roth collections in Switzerland. The collections include two species of notoungulates (Toxodon cf. T. platensis and Mesotherium cristatum) and one litoptern species (Macrauchenia patachonica). The occurrences are restricted to the early and middle Pleistocene (pre-Lujanian Stages/Ages). Although the SANUs diversity in the Roth collections is low in comparison with other groups (e.g., xenarthrans), some of the specimens are very complete, including skulls and postcranial remains. The completeness of the Ma. patachonica material allows an update and reinterpretation of some of the details of the dentition and the postcranial skeleton of this iconic species. In addition to its historical importance, the SANU specimens from the Roth collections provide important information to study the paleobiology and evolution of South American megafauna and evaluate hypotheses about their extinction in the continent.
Abstract A new ichnotaxonomic name, Transexcrementum cuniculus, is applied to tubular (cylindrical) tunnelings in coprolites. The type series of T. cuniculus consists of burrowed vertebrate (probably crocodilian) coprolites that originate from the Miocene Chesapeake Group of Maryland, U.S.A. These complex trace fossils exhibit the following combination of characters: burrows not lined nor backfilled; opening and transverse sections sub-circular; diameter supra-millimetric, up to ca. 20 mm, rather constant throughout; inner termination(s) rounded/conical; tunnel morphology straight or gently curved, sometimes branching; internal sculpturing sometimes present in form of short and irregularly oriented scratches and gouges. Clusters of the same kinds of gouges may also mark the outer surface of the coprolite. The tunneling tracemaker likely engaged in coprophagy; however, it is unclear what kind of organisms could have produced these burrows. Judging from the overall rarity of Transexcrementum cuniculus occurrences in the fossil record, the tracemaker responsible for the burrows might also have been rare, or fed on faeces only occasionally. ZooBank LSID: urn:lsid:zoobank.org:pub:DE755233-4F0E-48D1-A667-7AAD96B56B60
Marcello G. Simões, Vitor B. Guerrini, Suzana A. Matos
et al.
The genus Leinzia is a typical member of the renowned Artinskian–Wuchiapingian (Permian) endemic bivalve fauna of the Passa Dois Group, Paraná Basin, Brazil. The extraordinary shells of Leinzia, characterized by a rostrum extending from the anterior cardinal margin led certain authors to regard them as bivalved arthropods (Spinicaudata). Due to the unusual morphology and typically poor preservation of the available specimens, the taxonomic position of Leinzia still remains obscure. Leinzia has been variously referred either to the Pterioida, the Crassatelloidea, the Sanguinolitidae, or the Megadesmidae, or to the Pholadomyida. Herein, based on a detailed review of the topotype material and description of newly found specimens of Leinzia from the Serrinha Member, Rio do Rasto Formation, southern Brazil, we shed light on the taxonomic position of this genus. The hinge of the right valve with its large, blunt, anteriorly inclined subumbonal tooth and corresponding socket in the left valve coupled with the absence of true lateral teeth indicate close affinities to Pyramus and Cowperesia. Thus, the data here strongly suggest a Pachydomidae (Edmondioidea) rather than a Crassatelloidea affinity for Leinzia. Conversely, Leinzia differs from all other known Pachydomidae due to its anteriorly rostrate and posteriorly elongated shell. Finally, detailed stratigraphic data indicate that the vertical distribution of Leinzia is constrained to the middle part of the Guadalupian Serrinha Member of the Rio do Rasto Formation.
D. Cary Woodruff, David Trexler, Susannah C.R. Maidment
Two partial skeletons from Montana represent the northernmost occurrences of Stegosauria within North America. One of these specimens represents the northernmost dinosaur fossil ever recovered from the Morrison Formation. Consisting of fragmentary cranial and postcranial remains, these specimens are contributing to our knowledge of the record and distribution of dinosaurs within the Morrison Formation from Montana. While the stegosaurs of the Morrison Formation consist of Alcovasaurus, Hesperosaurus, and Stegosaurus, the only positively identified stegosaur from Montana thus far is Hesperosaurus. Unfortunately, neither of these new specimens exhibit diagnostic autapomorphies. Nonetheless, these specimens are important data points due to their geographic significance, and some aspects of their morphologies are striking. In one specimen, the teeth express a high degree of wear usually unobserved within this clade—potentially illuminating the progression of the chewing motion in derived stegosaurs. Other morphologies, though not histologically examined in this analysis, have the potential to be important indicators for maturational inferences. In suite with other specimens from the northern extent of the formation, these specimens contribute to the ongoing discussion that body size may be latitudinally significant for stegosaurs—an intriguing geographical hypothesis which further emphasizes that size is not an undeviating proxy for maturity in dinosaurs.
Ninon Robin, Barry W.M. Van Bakel, Marie-Madeleine Blanc-Valleron
et al.
AbstractKerguelen Islands are predominantly volcanic lands, thus fossil references are very uncommon. However, its Miocene fossils are of specific interest for understanding migration routes of some taxa during the Cenozoic, given the intermediary position of Kerguelen with various continents. Despite this fossil rarity, we studied herein hundreds of nodules corresponding to the sole known fossil brachyurans (and unique Decapoda) from Kerguelen both for their systematics and their preservation. Indeed, these crabs display some internal fragile structures that are rarely fossilized, such as the gills’ branchial lamellae, preserved in volume. The preservation of these gills and their diagenetic features were documented through traditional imagery (SEM), including morphological comparison to modern gills, and with petrographic and geochemical analyses (EDS, X-ray diffractometry). Some cheilostome bryozoans were observed as probable foulers of the crabs carcasses. The fossil material corresponds to a new cancrid crab (Romaleon franciscaen. sp.) and its occurrence may imply a novel route from South America westward for the geographic migration of the genusRomaleon, since its Cretaceous emergence. The cup-shape and the number and the organization of the gills in these fossil Cancridae specimens are similar to those observed in their extant representatives. Gill preservation in 3D is linked to very early phosphatization of the system during diagenesis, as shown by the nodule matrix, and likely to deposition of a thin clayey cover on the soft-tissues. The implication of intrinsic phosphorous in the differential phosphatization of the crabs’ anatomy remains difficult to determine.
José Francisco Baeza-Carratalá, Fernando Pérez-Valera, Juan Alberto Pérez-Valera
Triassic brachiopods from the Betic Range were unknown hitherto. Herein we describe the first brachiopod occurrences in the early Ladinian of this domain referable to a new genus and species Misunithyris goyi derived from three localities of the south-Iberian Triassic outcrops. The analysis of internal and external characters of this brachiopod allowed to characterize systematically and biogeographically this fauna in a chronostratigraphic interval when the paucity of brachiopod records is attributable to the entire peri-Iberian epicontinental platform system established in the westernmost Tethyan margin. The new record is endemic to the Betic Range and represents a new faunal constituent of the multicostate zeillerids stock. This fauna inhabited the epicontinental seas of the Sephardic bioprovince since a closer affinity with the low-latitude Tethyan assemblages is revealed. The possible linkage of the Triassic stock with the Early–Middle Jurassic multicostate zeillerid representatives suggests feasible phylogenetic relationships between both groups.
Agustín G. Martinelli, Marina Bento Soares, Téo Veiga De Oliveira
et al.
The dental anatomy of Candelariodon barberenai from the Dinodontosaurus Assemblage Zone (Pinheiros-Chiniquá Sequence, Santa Maria Supersequence, late Ladinian–early Carnian) of south Brazil, is redescribed. Candelariodon was originally classified as Eucynodontia incertae sedis and our analysis recovered this taxon deeply nested within Probainognathia, as the sister taxon of Potheriodon plus Prozostrodontia. The lower postcanine dentition of Candelariodon has several apomorphies shared with Prozostrodon, Santacruzgnathus, Brasilodon/Brasilitherium, and some basal mammaliaforms (Morganucodon, Megazostrodon), such as a lingual cingulum with discrete cusps e and g and two distinct morphologies in the tooth row. The reinterpretation of Candelariodon as a probainognatian cynodont more derived than Probainognathus and the rich Brazilian fossil record document an important adaptive radiation of non-mammaliaform prozostrodontians and closely related forms prior to the origin of the mammaliaform clade.
Benjamin Gügel, Kenneth De Baets, Iwan Jerjen
et al.
Machaeridians are an extinct group of armoured annelids, which are mainly known from isolated sclerites present from the Ordovician to the Permian. Based on articulated specimens with preserved soft-tissues and trace fossils, derived machaeridians are interpreted to have an infaunal burrowing mode of life. However, the taphonomy of sclerite associations is still largely unstudied. We herein investigated associated sclerites from the Middle Devonian of China using micro-computer tomography and 3D-analysis. These sclerites belong to a single individual and lie in close proximity. The absence of indications for current alignment, major bioturbation or other processes causing a disarticulation as reflected in the randomly arranged dacryoconarids suggest that the sclerites became disarticulated in the course of the normal decay processes, perhaps aided by scavenging and incomplete burial. The unique morphology of the sclerites indicates that the specimen presented here belongs to a previously undescribed species, which we describe herein as Lepidocoleus kuangguoduni sp. nov.
Marcus M. Key, Patrick N. Wyse Jackson, Stephen H. Felton
AbstractClusters of associated colony fragments discovered weathering out of bedding planes in the Upper Ordovician of the Cincinnati, Ohio, region provide a rare opportunity to quantify intracolony variation in ramose stenolaemate bryozoans. Sixteen colonies were reassembled as completely as possible from 198 fragments, and the following colony-level characters were measured: colony dimensions, branch link length and diameter, and branch order. Results indicate that branch link length and diameter systematically decrease as colonies grow via branch bifurcation. Branching ratio (i.e., the number of distal first-order branches divided by the number of immediately proximal second-order branches) appears to be more genetically than environmentally controlled and to be consistent among orders of stenolaemates and perhaps across the phylum. Colonies with endozones mined out by endoskeletozoans result in broken branches as opposed to pristine growing tips. This varies stratigraphically, perhaps in response to the distribution of the boring animals. The rarity of borers and the systematic proximal increase in branch diameter in these colonies suggest the zooids in the proximal portions of the colonies were alive at the time of colony death. If the time and effort can be invested in reassembling colonies, these morphometric data can then be applied to taxonomic, phylogenetic, and paleoenvironmental studies.
The study of the strophomenide brachiopods of the subfamily Rafinesquininae present in the main Upper Ordovician sections, representing the Mediterranean margin of Gondwana, has revealed an increase in diversity of the group at the region during that time. The studied collections are from the Moroccan Anti-Atlas, the Iberian and the Armorican massifs, the Iberian Chains, Pyrenees, Montagne Noire, Sardinia, and Bohemia. Two genera of the subfamily Rafinesquininae have been recorded. Of them, the cosmopolitan Rafinesquina is the only one previously reported from the region and Kjaerina is found for the first time outside Avalonia, Baltica, and Laurentia. Additionally, two new subgenera have been described, Kjaerina (Villasina) and Rafinesquina (Mesogeina). Furthermore, the new species Rafinesquina (Mesogeina) gabianensis, Rafinesquina (Mesogeina) loredensis, Kjaerina (Kjaerina) gondwanensis, Kjaerina (Villasina) pedronaensis, Kjaerina (Villasina) pyrenaica, and Kjaerina (Villasina) meloui have been described. In addition, other species of these genera previously known from isolated localities in the region, such as Rafinesquina pseudoloricata, Rafinesquina pomoides, and Hedstroemina almadenensis are revised and their geographic range expanded. The adaptive radiation experienced by the rafinesquinines at the Mediterranean region during middle to late Katian, was probably related to changes in the regime of sedimentation and water temperature caused by the global warming Boda event.
Silvina S. Garralla, Luisa M. Anzótegui, Lilia R. Mautino
Resumen. Los objetivos de este trabajo son relacionar las paleofloras del Mioceno–Plioceno del norte de la Argentina que caracterizan a cada formación y a cada período, comparar las registradas en el noroeste con las del nordeste a fin de establecer sus diferencias o semejanzas e inferir la evolución florística y paleoambiental a través del intervalo estratigráfico considerado. Las formaciones seleccionadas son las de Paraná e Ituzaingó en el nordeste y las de Anta, San José, Chiquimil, Palo Pintado, Aloformación Playa del Zorro, Andalhuala, del Buey y pozo YPF.SE.x-2 Los Horcones en el noroeste. Se reconocieron 430 especies que fueron volcadas como presencia-ausencia en una base de datos en la que se consignó, para cada una de ellas, familia, formación, tipo de fósil, hábito, comunidad vegetal y representante actual más cercano al fósil. Se aplicó el análisis de agrupamiento simultáneo en modo Q para las formaciones y en modo R para las especies, utilizando la medida de Distancia de Sorensen. Las paleofloras analizadas comparten el 15% del total de las especies relevadas. El análisis integral comparativo permitió señalar una diferenciación paleovegetacional y paleoambiental entre ambas regiones. En el noroeste, desde el Mioceno temprano al Plioceno se registraron estepas graminosas, bosques ribereños y bosques secos con estacionalidad y sabanas herbáceas, es decir una manifiesta alternancia de cambios ambientales y vegetacionales relacionados al clima. En el nordeste, en cambio, prevalecen los bosques ribereños y bosques secos con estacionalidad de moderados cambios ambientales.
PALABRAS CLAVE. Paleovegetación. Paleoambiente. Neógeno. Norte de Argentina.
Abstract. MIOCENE–PLIOCENE PALEOFLORISTIC RELATIONS OF NORTHERN ARGENTINA. The aims of this paper are to explore the relationships among the Miocene–Pliocene palaeofloras of Northern Argentina, characterizing each formation and period of time, to compare those located in the Northwest with the ones from in the Northeast in order to establish their differences or similarities, and to infer the floristic and paleoenvironmental evolution through the stratigraphic interval considered. The selected formations are Paraná and Ituzaingó in the Northeast and Anta, San José, Chiquimil, Palo Pintado, Playa del Zorro Alloformation, Andalhuala, del Buey, and YPF pit. SE.x-2 Los Horcones in the Northwest. A total number of 430 species were identified and compiled as presence-absence in a database, where each of them was categorized into family, formation, type of fossil, habit, plant community and closest extant representative to fossil species. A cluster analysis was conducted based on the resulted matrix, applying a Q mode for formations and R mode for species, using the Sorensen Distance measure. The paleofloras analyzed share 15% of the identified species. The comprehensive comparative analysis allowed to distinguish a paleovegetational and paleoenvironmental differentiation between both regions. In the Northwest, from early Miocene to Pliocene, grass steppes, riparian forests, and seasonally dry forests and herbaceous savannas were found; this is an alternating manifest in the vegetational and environmental change related to climate. In the Northeast, instead, riparian forests and dry forests with more seasonal environment change prevailed.
KEY WORDS. Paleovegetation. Paleoenvironment. Neogene. Northern Argentina.