Matthew Edward Scarborough, Heinz Furrer, Torsten M. Scheyer
et al.
Here we report on the anatomical re-investigation of a Late Pleistocene (Middle Würmian Interstadial, MIS 3, ca. 40–50 ka BP) perinatal woolly mammoth excavated in 1890-91 from Niederweningen, Switzerland, the first perinatal mammoth ever scientifically studied. In order to narrow down its age at death we compare perinatal woolly mammoths and African elephants in terms of their (i) ontogenetic allometry, especially in woolly mammoths from Russia, (ii) bone microstructure, (iii) tooth eruption sequences, and (iv) the timing of cranial suture closure. A distinct layer of postnatal bone deposition in the tibial midshaft and maxilla identified using micro-CT scanning, in particular, provides strong evidence of a post-natal ontogeny despite the lack of obvious wear in the dentition, suggesting an age of no more than a few months. Odontochronologically, the individual probably belongs to Jachmann’s (1988) Dental Stage 1 (3 months - 2 years), and tiny pits in the enamel/dentin tips of lamellar edges are analogous to those seen in juvenile M. primigenius from Russia (“Lyuba”), and are variously hypothesized to be caused by initial wear, spalling, dissolution pitting, incomplete mineralization, or eruption through the gums. Additionally, we describe anisomelia of uncertain aetiology, resulting in the stunting right fore-leg, perhaps contributing to the cause of its death. Finally, we discuss the significance to ecology and extinction of an altricial life-history strategy and the relatively rapid post-natal growth evidenced in woolly mammoths, a taxon with an exceptionally long gestation period.
Abstract A long neck is a morphological innovation in vertebrates, particularly iconic in many plesiosaurs, while the function of these long necks in plesiosaurs remains controversial. Here, we report Lijiangosaurus yongshengensis gen. et sp. nov. from a previously unknown early Middle Triassic locality in southwestern China. This taxon represents the earliest known sauropterygian evolving an exceptionally long neck with 42 cervical vertebrae, and is identified as a nothosaur rather than the immediate ancestors of plesiosaurs. Our discovery demonstrates that extreme cervical elongation developing more than 30 cervical vertebrae emerged in sauropterygians prior to the rise of plesiosaurs and their pistosaur ancestors. Furthermore, Lijiangosaurus possesses a unique type of accessory intervertebral articulation compared with other reptiles, and we attribute this structure to reducing body undulation. This discovery increases the known diversity of accessory intervertebral articulations in reptiles, and underscores the high plasticity of the vertebral column in the early evolution of sauropterygians.
Mariel Ferrari, Verónica Bertero, Marcelo G. Carrera
Gastropods from the Upper Ordovician of the Argentine Precordillera received less attention than other coeval marine invertebrates in this region. The present contribution supplies accurate taxonomic information recovering 10 gastropod genera which are represented by 10 species from the La Pola and Don Braulio formations (Sandbian and Hirnantian units, respectively) at the San Juan Province, Argentina: two species, namely Tetranota argentina sp. nov. and Clathrospira gondwanica sp. nov., are new to science. The gastropod association shows a remarkable diversity, and in contrast to other invertebrate groups reported in the Argentine Precordillera (e.g., trilobites, ostracodes, brachiopods, sponges, and bivalves) which had Gondwanan affinities during the Late Ordovician, the gastropod assemblage from the La Pola and Don Braulio formations had major palaeobiogeographical similarities with their Northern Hemisphere (Laurentia, Avalonia, and Baltica) counterparts. The occurrence of the genus Clathrospira suggests that it could have been the first precursor of the order Pleurotomariida in South America during the Sandbian–Hirnantian, and can help to shed light on the origin of this clade in the southernmost Gondwana continent as early as Palaeozoic times.
<p>The Benguela Upwelling System (BUS), located in the southeastern Atlantic Ocean, represents one of the world's most productive regions. This system is delimited to the south by the Agulhas retroflection region. The northern boundary of the BUS is, instead, represented by the Angola–Benguela Front (ABF), which is a thermal feature separating warm waters of the Angola Basin (including the South Atlantic Central Water; SACW) from the cooler Benguela Oceanic Current (BOC). We performed statistical analyses on planktonic foraminiferal assemblages in 94 samples from Holes U1575A and U1576A, cored during International Ocean Discovery Program (IODP) Expedition 391. Drilled sites are located along the Tristan–Gough–Walvis Ridge (TGW) seamount track in the northern sector of the BUS (offshore the Namibian continental margin). The analyzed stratigraphic intervals span the Early–Late Pleistocene, marked by the Early–Middle Pleistocene transition (EMPT; 1.40–0.40 Myr), during which important glacial–interglacial sea surface temperature (SST) variabilities occurred. This work provides novel insights on the local paleoceanographic evolution of the northern BUS and associated thermocline variability based on the ecological significance of the foraminiferal assemblages. Specifically, variations in the assemblage content allowed us to characterize the different water masses (BOC, SACW, and Agulhas waters) and reconstruct their interactions during the Quaternary. The interplay of the previously mentioned water masses induced perturbations in the BUS (ABF latitudinal shifts and input of tropical waters from the Agulhas retroflection region). Furthermore, we investigated the possible link between changes in the paleoceanographic conditions and climatic events (e.g., Benguela Niño-/Niña-like phases and deglaciation stages) recorded since the EMPT.</p>
Introduction: Coral reefs, among the most invaluable ecosystems in the world, face escalating threats from climate change and anthropogenic activities. To decipher the genetic underpinnings of coral adaptation and resilience, we undertook comprehensive transcriptome profiling of two emblematic coral species, Montipora foliosa and Montipora capricornis, leveraging PacBio Iso-Seq technology. These species were strategically selected for their ecological significance and their taxonomic proximity within the Anthozoa class.Methods: Our study encompassed the generation of pristine transcriptomes, followed by thorough functional annotation via diverse databases. Subsequently, we quantified transcript abundance and scrutinized gene expression patterns, revealing notable distinctions between the two species.Results: Intriguingly, shared orthologous genes were identified across a spectrum of coral species, highlighting a substantial genetic conservation within scleractinian corals. Importantly, a subset of genes, integral to biomineralization processes, emerged as exclusive to scleractinian corals, shedding light on their intricate evolutionary history. Furthermore, we discerned pronounced upregulation of genes linked to immunity, stress response, and oxidative-reduction processes in M. foliosa relative to M. capricornis. These findings hint at the presence of more robust mechanisms in M. foliosa for maintaining internal equilibrium and effectively navigating external challenges, underpinning its potential ecological advantage. Beyond elucidating genetic adaptation in corals, our research underscores the urgency of preserving genetic diversity within coral populations.Discussion: These insights hold promise for informed conservation strategies aimed at safeguarding these imperiled ecosystems, bearing ecological and economic significance. In synthesis, our study seamlessly integrates genomic inquiry with ecological relevance, bridging the gap between molecular insights and the imperative to conserve coral reefs in the face of mounting threats.
The genus Semicytherura Wagner, 1957 has nearly 300 species, is common in shallow and marginal marine habitats, and has a worldwide distribution. It is divided into several species groups, of which the Semicytherura henryhowei Hanai &amp; Ikeya, 1977 group is one of the most frequently recorded in temperate Asia. A previous study indicated that many of its members are actually species complexes, and that several morphotypes could be distinguished by carapace shape and ornamentation. We review these complexes and conclude that the henryhowei group currently contains 29 species, nine of which are undescribed. We also provide an illustrated guide and a key to species, based on newly standardized carapace ridge terminology. This enabled us to describe one new species from the extant (i.e., present-day) sediments in Jeju Island, Korea, S. kiosti sp. nov. We also found one juvenile valve of S. kazahana Yamada, Tsukagoshi &amp; Ikeya, 2005, the first official illustrated record of this species from Korean waters. Our revised spatial and temporal distributions of fossil and extant records from this group provide new insights into trans-Arctic interchange of ostracod fauna from the Late Miocene onwards.
<p>A study of Baltic amber revealed a new fossil species of the genus
<i>Bacanius</i> LeConte, 1853. <i>Bacanius gorskii</i> sp. nov. differs from the congener described previously from
Eocene Rovno amber, <i>B. kirejtshuki</i> Sokolov and Perkovsky, in the shape of meso-metaventral
suture, incomplete subhumeral stria, and the impunctate prosternal lobe (urn:lsid:zoobank.org:pub:EE9C6859-607A-4134-9037-8385601CF42F).</p>
Masaaki Chiwa, Yasuhiro Utsumi, Naoaki Tashiro
et al.
Abstract Rawanbuki, a variety of Japanese butterbur (Petasites japonicus subsp. giganteus), grow naturally along the Rawan River, Hokkaido, northern Japan. Most plants reach 2–3 m in height and 10 cm in diameter in 2 months and are much larger than those grown along other rivers. We examined the hypothesis that nutrients exported from upland streams enhance the growth of the Rawanbuki. Nutrient concentrations, including nitrogen, phosphorus, and base cations, in the Rawan River were much higher than those in rivers of adjacent watersheds. High nutrient concentrations and moisture contents were found in soil along the Rawan River and a significant relationship was found between physicochemical soil conditions and aboveground biomass of butterburs. This indicates that extremely large Rawanbuki plants could be caused by these high nutrient concentrations and moisture contents in the soils. A manipulation experiment showed that fertilization simulated the growth environment along the Rawan River and enhanced the stem height and stem diameter of butterburs. This study concluded that the extremely large butterburs are caused by a large amount of nutrients exported from upland areas. These results are the first demonstration of the role of stream water nutrients in enlarging agricultural crops.
L. Courtenay, R. Huguet, D. González-Aguilera
et al.
The concept of equifinality is currently one of the largest issues in taphonomy, frequently leading analysts to erroneously interpret the formation and functionality of archaeological and paleontological sites. An example of this equifinality can be found in the differentiation between anthropic cut marks and other traces on bone produced by natural agents, such as that of sedimentary abrasion and trampling. These issues are a key component in the understanding of early human evolution, yet frequently rely on qualitative features for their identification. Unfortunately, qualitative data is commonly susceptible to subjectivity, producing insecurity in research through analyst experience. The present study intends to confront these issues through a hybrid methodological approach. Here, we combine Geometric Morphometric data, 3D digital microscopy, and Deep Learning Neural Networks to provide a means of empirically classifying taphonomic traces on bone. Results obtained are able to reach over 95% classification, providing a possible means of overcoming taphonomic equifinality in the archaeological and paleontological register.
Planktonic foraminifera were studied in the upper Albian to Cenomanian sedimentary sequence of the Monte Petrano and Le Brecce stratigraphic sections located in the Umbria-Marche Basin (central Italy), and of Hole 547A and Site 545 drilled by the Deep Sea Drilling Project (DSDP) on the Mazagan Plateau (offshore Morocco, northeast Atlantic Ocean). Biostratigraphic results allow the identification of a stratigraphically ordered sequence of bioevents that have proved to be reliable for regional and interregional correlations, from older to younger: the lowest occurrences (LOs) of Th. appenninica, Pl. buxtorfi, Pa. libyca, Th. brotzeni in the Albian, and the LOs of Th. globotruncanoides, Th. greenhornensis and Rt. cushmani in the Cenomanian sediments. We remark the difficulty in the identification of the Th. reicheli Zone used in the Tethyan biozonation because of the rarity and absence of the species in many low to mid- latitude pelagic sequences. To overcome the problem, we use the Th. greenhornensis Zone defined as the stratigraphic interval between the lowest occurrence (LO) of Th. greenhornensis and the LO of Rt. cushmani. The LO of Th. greenhornensis is a solid bioevent with the nominal species characterized by a wide geographic distribution and occurring close to the LO of Th. reicheli where the latter species is present. The studied stratigraphic sections are compared with the coeval Mont Risou section in the Vocontian Basin and the record from Blake Nose in the western North Atlantic to verify the correlation and synchronicity of biostratigraphic and chemostratigraphic events including the Oceanic Anoxic Events 1d (OAE1d) and the Mid Cenomanian Event (MCE).
One of the oldest species of fossil woods with affinities to Cupressaceae is Cupressinoxylon zamunerae from the Ladinian, Middle Triassic of Argentina, but the generic assignment of this species was a subject of debate. The main character that is in conflict with Cupressinoxylon is the presence of ray tracheids in C. zamunerae, a character absent in the original diagnosis of the genus. In order to clarify this issue, original microscopic slides of the type materials were restudied herein, and also new sections and SEM samples were observed. The supposed ray tracheids turned out to be parenchyma cells. A new combination is established, relating C. zamunerae to Juniperoxylon due to the markedly pitted ray parenchyma cells walls. This fossil species is the first mention of Juniperoxylon from the Mesozoic of Gondwana and the oldest record worldwide until date.
The recent find of a new complete specimen of Psephoderma alpinum Meyer, 1858 in the Norian Calcare di Zorzino (Zorzino Limestone), in northern Italy, adds to our knowledge of the osteology of this species. The new specimen is the largest so far collected, reaching 180 cm in length. Allometric growth of the limbs during ontogeny is demonstrated. A new interpretation of its palaeoecology and mode of life is given on the bases of both functional morphology and palaeoenvironmental observation. The streamlined keeled carapace is interpreted as having a hydrodynamic rather than a defensive function. The long, stiff tail and, probably, the dorsal caudal plate served for balance. The gap in the carapace, above the sacral region, enabled Psephoderma to swim at least as well as trionychid turtles, though no particular swimming adaptations of the pelvic girdle and of the femur are observed. Invertebrates and a rich fish fauna were found together with these placodonts, allowing the restoration of the oxic part of the basins environment as a normal marine one. The surface waters were influenced by tides that possibly generated rarher strong local currents close to the mouth of tidal channels crossing the platform. This provided for a rich nectonic and benthic life in the more superficial waters: Psephoderma fed on bissate molluscs, such as Modiolus and Isognomon, dwelling on shallow oxic bottoms at the basins edge. Due to water stratification, a long-lasting anoxic environment developed in the deepest part of the basins themselves, allowing fine preservation (Konservat-Lagerstaetten) of allochthonous organisms.