Taxonomic Affinities Research Articles

The bivalved arthropod Caudicaella aff. bispinata from the Heatherdale Shale (Cambrian Stage 3), South Australia

Sunellids are early Cambrian bivalved arthropods first recognized in South China that are important for understanding the early evolution of the group. However, their taxonomic affinity and distribution beyond South China is poorly known. Furthermore, the relationship between members of the Sunellidae and the globally dispersed Isoxys remains unclear. Recently, rare specimens of the sunellid Caudicaella aff. bispinata have been recovered from the lower Cambrian (Series 2, Stage 3) Heatherdale Shale, eastern Stansbury Basin, South Australia, representing the first record of the group from East Gondwana. Caudicaella aff. bispinata from Australia bears a semicircular carapace, a pair of anterodorsal sulci, anterior and posterior cardinal spines, as well as a distinct thick border or margin. It most closely resembles Caudicaella bispinata from the Shuijingtuo Formation in western Hubei Province, South China. The new discovery adds support for strong faunal similarity of the Konservat-Lagerstätten of South Australia and South China and extends the known geographical range of Cambrian sunellids to East Gondwana. The occurrence of Caudicaella bispinata in South China and Caudicaella aff. bispinata in East Gondwana strengthens the biostratigraphic correlation between those two palaeo-continents.

Blakea cubarralensis (Melastomataceae: Pyxidantheae): a new species from Colombia

A new species of Blakea (Melastomataceae) from the department of Meta, Colombia is described and illustrated here, with comments on its etymology, distribution and habitat, phenology, conservation status and taxonomic affinities. Blakea cubarralensis sp. nov. is readily distinguished by its floral bracteoles that are longer than the calyx lobes, the outer pair ovate-elliptic with a long-acuminate apex and 3-nerved, the lobed calyx, the anther connective prolonged into a blunt knob and the ovary 12-locular. The new species is categorized as Endangered (EN) according to the IUCN Red List. This novelty highlights the importance of sub-andean forests and the need to conserve and increase botanical explorations in them.

The role of predation and pesticides in shaping phytoplankton dynamics in a short microcosms experiment.

Aquatic organisms are subject to various forcing factors that affect their structure, some of which are natural, while others result from human activities, both having variable effects. This study aimed to determine the importance of a natural stressor (zooplankton) and an herbicide (atrazine) on phytoplankton density and morphological composition in a microcosm experiment. A natural phytoplankton assemblage was exposed to two zooplankton predators: a copepod (Argyrodiaptomus falcifer) and a cladoceran (Ceriodaphnia dubia), and to atrazine (27 µg L-1), in three combinations of factors (zooplankton treatments (Z), atrazine treatment (A), the combination of both (ZA)) plus a Control. The experiment lasted 48 h. Samples were taken at the beginning and the end of the experiment, and relevant limnological variables, including inorganic nutrient concentrations, were considered. Results indicated differences in phytoplankton densities when treatments were compared with Control. In this respect, Chlorophyceae, Euglenophyceae, and Bacillariophyceae exhibited more changes than other phytoplankton classes. Chlorophyceae densities tended to be higher in the Control than in the treatments; the combination of zooplankton and atrazine favored Euglenophyceae, while atrazine favored Bacillariophyceae densities. Regarding morphological groups, unicellular and small colonies (<35 µm), showed differences between the Control and particularly with Z treatment, colonial-cenobia forms were negatively affected by atrazine and silica forms were favored by both stressors combined. It is concluded that interactions among natural and anthropogenic stressors could be complex, influencing factors such as phytoplankton taxonomical affinities, morphological groups, and the nature of the stressor applied.

Revealing the use of dental indices to infer taxonomic variation in sauropod dinosaurs

AbstractSauropod teeth are commonly categorized taxonomically by two well‐established measurement indices: slenderness index (SI; apicobasal height/mesiodistal width), which quantifies breadth, and compression index (CI; labiolingual width/mesiodistal width), which quantifies cross‐sectional circularity. Although both indices are used to infer high‐level taxonomic affinities, little is known about the linear relationships between the constituent measurements or how the indices vary intra‐cranially and at lower taxonomic levels. Here, we evaluate these relationships using a novel dataset of sauropod teeth (N = 898) spanning all major sauropod groups. Results for both indices indicate significant differential scaling within Sauropodomorpha, both in slope and elevation. Broad‐crowned sauropods mostly display positive allometry in SI compared to isometry in narrow‐crowned sauropods. However, this distinction is less clear with CI as most sauropods display isometry, whilst non‐sauropod sauropodomorphs (e.g. Plateosauridae) display positive allometry. An anova reveals SI varies significantly with genus and tooth position. Specifically, jaw type (maxilla and dentary) is significant within Plateosauridae, whilst tooth position is significant within titanosaurs. Overall, variation within CI is restricted to genus. Our findings reveal that whilst indices have taxonomic utility, there are caveats. The measurements used to calculate the indices exhibit significant allometry, indicating that index values are size‐dependent. Furthermore, the indices may not accurately reflect size heterodont conditions present among early‐branching sauropodomorphs. Our study highlights the importance of quantifying taxonomic relationships of measurement data, which can be used to inform hypotheses regarding the physiological and palaeoecological drivers influencing tooth shape evolution.

Seed morphology of species of Spergula and Spergularia (Caryophyllaceae) occurring in Ukraine and its taxonomic significance

The micro- and macromorphological characteristics of seeds of species of the genera Spergula and Spergularia in the flora of Ukraine were studied in order to identify new diagnostic characters useful for solving taxonomic issues. The ultrastructure of the seed surface was studied using a scanning electron microscope. Seeds of some species of these genera are similar in appearance (especially with a wide wing — Spergula morisonii and Spergularia marina), which can be one of the confirmations of the close taxonomic affinity of these genera. The results of our study showed that the ultrastructure patterns of the surface of seeds of Spergula and Spergularia species differ among themselves within these genera but for some species can be used as diagnostic characters for their identification. The data obtained confirm the results of our previous research on the taxonomic status of some representatives of the studied taxa (Fedoronchuk, 2023). In particular, taking into account the similarity of seed ultrastructure and other characteristics that have been proposed previously, we consider Spergula vulgaris a synonym of Spergula arvensis subsp. arvensis, S. vernalis — a synonym of S. morisonii, Spergularia media — a synonym of Spergularia marina, and Spergularia salina — a synonym of Spergularia marina. Differences in the surface ultrastructure of Spergula sativa and Spergula arvensis subsp. arvensis, which is consistent with our understanding of the taxon (Fedoronchuk, 2023) as Spergula arvensis subsp. sativa, as well as between Spergula maxima and Spergula arvensis subsp. arvensis, accordingly we propose — Spergula arvensis subsp. maxima. Compiled descriptions of the surface ultrastructure of seeds of Spergula and Spergularia species collected in the territory of Ukraine can be used as a model for assessing the possible variability of the morphological characters of these species in other regions of the world.

Heracleum munzurense (Apiaceae), a new species from East Anatolia, Turkey and taxonomic position of Tetrataenium lasiopetalum

A new species, Heracleum munzurense (Apiaceae), is described from East Anatolia, Turkey. It grows in damp places formation of the Munzur Mountains in the district of Pülümür (Tunceli Province). The taxonomic affinities of the new species were determined by analyzing morphological data and through a molecular phylogenetic study of nrITS/ETS. The new species is morphologically and genetically related to H. apiifolium and H. pastinaca, but differs mainly in stems, leaves, pedicels, rays and petals pubescence, petals size, fruit hairs, and size features. The anatomical structure of the fruit is given. The diagnostic morphological characters of the new species are discussed. In this study, the geographical distribution of the new species and the related taxa H. apiifolium, H. lasiopetalum, and H. pastinaca is mapped. In addition, the habitat, ecology, phenology, and conservation status of the new species are also provided. Tetrataenium lasiopetalum is also closely related to this group of species. Common morphological features and results of molecular phylogenetic study suggest to transfer this species back to the genus Heracleum.

Taxonomic Revision and Morphometric Analysis of Gamochaeta (Asteraceae, Gnaphalieae)

Gamochaeta Wedd. (Asteraceae, Gnaphalieae) is a New World genus with a center of diversity in South America. The genus is characterized by capitula usually arranged in spikes or headlike clusters; pistillate florets outnumbering the bisexual florets; truncate style branches with apical sweeping trichomes; pappus bristles connate at the base into a ring that falls as a unit; and achenes with usually globose twin trichomes. We present here the first morphometric analysis of this genus. Based upon these results, 53 species are recognized, and two are newly synonymized: G. neuquensis Cabrera under the name G. chamissonis (DC.) Cabrera, and G. impatiens G. L. Nesom under the name G. americana (Mill.) Wedd. A lectotype is newly designated for Gnaphalium spiciforme Sch. Bip. The occurrence in southern Argentina of Gamochaeta procumbens (Phil.) Cabrera is reported for the first time, and G. standleyi (Steyerm.) G. L. Nesom is new for Colombia. One species, Gamochaeta thouarsii (Spreng.) Anderb., is treated as dubious. A key to the species is provided, as well as morphological descriptions, synonymy, distribution and habitat information, distinguishing characters, taxonomic affinities, distribution maps, illustrations of the species, and additional material examined.

Lower Cretaceous iguanodontian dinosaurs from the southwestern margin of Gondwana

The early evolutionary and biogeographical history of Gondwanan iguanodontian dinosaurs is poorly understood due to their scarce Lower Cretaceous fossil record. In South America, the Lower Cretaceous iguanodontian osteological record is very fragmentary and most published reports cannot be used to discard or confirm hadrosauroid affinities. The single exception is Tietasaura from Brazil, whose incomplete femur shows a combination of traits found only in non-hadrosauroid iguandontians. Furthermore, no skeletal remains whatsoever of Lower Cretaceous iguanodontians have been reported from the western margin of South America. Here, we describe an isolated ornithopod caudal centrum (SGO.PV.22900) from the Lower Cretaceous Quebrada Monardes Formation in the Atacama Desert, northern Chile. Although incomplete, SGO.PV.22900 presents iguanodontian traits, such as the sub-hexagonal contour of the articular faces, the rectangular profile in lateral view and the absence of transverse processes below the neurocentral suture. We were also able to use quantitative measurements to explore taxonomic affinities, by carrying out a Linear Discriminant Analysis (LDA) and a Principal Components Analysis (PCA) using measurements of caudal centra of several iguanodontian species. The results of both analyses are consistent with those of our comparisons and suggest that SGO.PV.22900 belongs to a non-hadrosauroid iguanodontian ornithopod. This specimen represents one of the most compelling and best documented pieces of osteological evidence of Lower Cretaceous non-hadrosauroid iguanodontian dinosaurs in South America and provides further support for the presence of iguanodontians in the southwestern margin of Gondwana since at least the Early Cretaceous, as previously suggested based on footprints.

The first hadrosauroid eggshell from the Aix-en-Provence Basin (late Maastrichtian) of France

ABSTRACT Nearly all dinosaur egg or oospecies occurrences from the Upper Cretaceous of France have been attributed to titanosaur dinosaurs. Here, we describe the first occurrence of probable hadrosauroid eggshells from France, which we assign to a new oospecies, Paraspheroolithus porcarboris oosp. nov. (oofamily: Spheroolithidae), from the upper ‘Argiles et Grès à Reptiles’ Formation (upper Maastrichtian) of Aix-en-Provence. Paraspheroolithus porcarboris differs from all other spheroolithid oospecies in the following combination of characteristics: prolatospherulitic morphotype, prolatocanaliculate pore system, prominent anastomosing ornamentation, medium eggshell thickness, less defined horizontal accretion lines and high pore density. The spheroolithid affinity places the new ootaxon outside oofamilies ascribed to titanosaurs (i.e. Megaloolithidae and Fusioolithidae), and thus its discovery expands the parataxonomic diversity of this region and formation. We suggest the taxonomic affinity of Spheroolithidae is somewhat broader than Hadrosauroidea, potentially encompassing all Ornithopoda. However, a hadrosauroid affinity remains the most plausible for Paraspheroolithus porcarboris based on the absence of other ornithopod remains from late Maastrichtian deposits of the Ibero-Armorican Island.

New archosauromorph remains provide data on the age of a unique Late Triassic assemblage from southern Brazil

The Santa Maria Supersequence, an important stratigraphic unit in the Paraná Basin, yielded a diverse range of Triassic tetrapod assemblages, providing valuable insights into the evolutionary history of southwestern Pangea. This study focuses on the Candelária Sequence of the Santa Maria Supersequence, which includes the Hyperodapedon Assemblage Zone (AZ) and the Riograndia AZ. The Hyperodapedon AZ is characterized by the presence of Hyperodapedon rhynchosaurs alongside a diverse array of other taxa, including dinosaurs, pseudosuchians, and cynodonts. In contrast, the Riograndia AZ preserves mostly small cynodonts, lepidosauromorphs, and sauropodomorph dinosaurs. Whereas biostratigraphic correlations between several localities of the Candelária Sequence have been firmly established, certain sites, like the Niemeyer complex in the Agudo municipality of southern Brazil, present challenges because of their unusual assemblage composition, which result in ambiguous depositional ages. Despite yielding thousands of fossil specimens, the Niemeyer complex lacks index fossils typical of the known Brazilian AZs, making reliable correlation with other sites challenging. This study presents and describes new archosauromorph specimens discovered at the upper portion of the Niemeyer complex. The new materials include a rhynchosaur, a saurischian dinosaur, and a possible silesaurid, which represent the first record of these groups for the site. A phylogenetic analysis of the rhynchosaur material provides insights into its taxonomic affinities, offering valuable data for biostratigraphic comparisons. The new data reinforces an age (early Norian?) that is younger than that of the typical outcrops assigned to the Hyperodapedon AZ. Furthermore, these new specimens contribute to the unique assemblage of the Niemeyer complex, shedding light on its significance within the context of the Santa Maria Supersequence and the broader landscape of southern Brazil during the Triassic Period.

Inferring Taxonomic Affinities and Genetic Distances Using Morphological Features Extracted from Specimen Images: a Case Study with a Bivalve dataset.

Reconstructing the tree of life and understanding the relationships of taxa are core questions in evolutionary and systematic biology. The main advances in this field in the last decades were derived from molecular phylogenetics; however, for most species, molecular data are not available. Here, we explore the applicability of two deep learning methods - supervised classification approaches and unsupervised similarity learning - to infer organism relationships from specimen images. As a basis, we assembled an image dataset covering 4144 bivalve species belonging to 74 families across all orders and subclasses of the extant Bivalvia, with molecular phylogenetic data being available for all families and a complete taxonomic hierarchy for all species. The suitability of this dataset for deep learning experiments was evidenced by an ablation study resulting in almost 80% accuracy for identifications on the species level. Three sets of experiments were performed using our dataset. First, we included taxonomic hierarchy and genetic distances in a supervised learning approach to obtain predictions on several taxonomic levels simultaneously. Here, we stimulated the model to consider features shared between closely related taxa to be more critical for their classification than features shared with distantly related taxa, imprinting phylogenetic and taxonomic affinities into the architecture and training procedure. Second, we used transfer learning and similarity learning approaches for zero-shot experiments to identify the higher-level taxonomic affinities of test species that the models had not been trained on. The models assigned the unknown species to their respective genera with approximately 48% and 67% accuracy. Lastly, we used unsupervised similarity learning to infer the relatedness of the images without prior knowledge of their taxonomic or phylogenetic affinities. The results clearly showed similarities between visual appearance and genetic relationships at the higher taxonomic levels. The correlation was 0.6 for the most species-rich subclass (Imparidentia), ranging from 0.5 to 0.7 for the orders with the most images. Overall, the correlation between visual similarity and genetic distances at the family level was 0.78. However, fine-grained reconstructions based on these observed correlations, such as sister-taxa relationships, require further work. Overall, our results broaden the applicability of automated taxon identification systems and provide a new avenue for estimating phylogenetic relationships from specimen images.

Morphological and morphometric study of the hominin dental casts from Grotta-Riparo di Uluzzo C (Apulia, southern Italy).

Grotta-Riparo di Uluzzo C (Apulia, southern Italy) is a pivotal site for investigating the evolution of the Middle Paleolithic and the earliest phases of the Upper Paleolithic in southern Italy, as the extensive stratigraphic record of this site includes a thick Mousterian sequence followed by the Uluzzian. Here, we investigate the taxonomic affinity of seven unpublished deciduous human teeth retrieved from the site of Uluzzo C in 1960. The teeth are represented by seven plaster dental casts, which are housed at the Museo Civico di Paleontologia e Paletnologia in Maglie (Lecce, Apulia). The location of the original specimens remains unknown, rendering these casts the only human remains evidence yielded by Uluzzo C to date. Based on occlusal-view photographs and digital models of the casts, we examined the external morphology and morphometry of the teeth, comparing them to Homo sapiens and H. neanderthalensis samples. Through geometric morphometric methods and statistical analyses, we analyzed the crown outline of the deciduous molars. The teeth show morphological and morphometric features that are variably found in H. neanderthalensis, H. sapiens, or both. Specifically, crown outline analysis shows that all molars fall within H. neanderthalensis variability, except for Uluzzo 853 (lower right deciduous first molar), which falls within H. sapiens variability. This study provides the first taxonomic assessment of the hominin teeth from Uluzzo C. The results contribute additional insights into the Paleolithic peopling of southern Italy during a crucial period marked by the persistence of post-Tyrrhenian Neanderthal techno-complexes and the arrival of H. sapiens.

Unveiling Challenging Microbial Fossil Biosignatures from Rio Tinto with Micro-to-Nanoscale Chemical and Ultrastructural Imaging.

Understanding the nature and preservation of microbial traces in extreme environments is crucial for reconstructing Earth's early biosphere and for the search for life on other planets or moons. At Rio Tinto, southwestern Spain, ferric oxide and sulfate deposits similar to those discovered at Meridiani Planum, Mars, entomb a diversity of fossilized organisms, despite chemical conditions commonly thought to be challenging for life and fossil preservation. Investigating this unique fossil microbiota can elucidate ancient extremophile communities and the preservation of biosignatures in acidic environments on Earth and, potentially, Mars. In this study, we use an innovative multiscale approach that combines the state-of-the-art synchrotron X-ray nanoimaging methods of ptychographic X-ray computed laminography and nano-X-ray fluorescence to reveal Rio Tinto's microfossils at subcellular resolution. The unprecedented nanoscale views of several different specimens within their geological and geochemical contexts reveal novel intricacies of preserved microbial communities. Different morphotypes, ecological interactions, and possible taxonomic affinities were inferred based on qualitative and quantitative 3D ultrastructural information, whereas diagenetic processes and metabolic affinities were inferred from complementary chemical information. Our integrated nano-to-microscale analytical approach revealed previously invisible microbial and mineral interactions, which complemented and filled a gap of spatial resolution in conventional methods. Ultimately, this study contributes to the challenge of deciphering the faint chemical and morphological biosignatures that can indicate life's presence on the early Earth and on distant worlds.

Silicoflagellates and other siliceous micro- and nannofossils from Rupelian diatomites, southeastern Poland

The Eocene-Oligocene Transition is one of the major stages of the Cenozoic reshaping of the world oceans with associated changes in climate, of ocean coastlines and circulation patterns. This altogether created challenging environments for fossilization and preservation of native biota. Consequently, well preserved Oligocene fossils are infrequent worldwide and just as rare in the Central Paratethys. The well-preserved Rupelian (Early Oligocene) diatomites from the Skole Nappe, the external unit of the Outer Carpathians in southeastern Poland were deposited in the Central Paratethys. In some samples, in addition to diatoms, sediments also contain a great diversity of other silicified micro- and nannofossils. Here we report our findings of silicoflagellates (fifteen taxa from five genera), two rotosphaeridians, and several morphotypes of fossil scales, some of uncertain taxonomic affinity. Among silicoflagellates, the most common are species from genera Corbisema (C. triacantha, C. hastata, and C. apiculata) and Dictyocha (D. clinata and D. fibula). We also recovered scales of rotosphaeridians (Pinaciophora and possibly Rabdiophrys) and remains of organisms of uncertain affinity (Clathropyxidella and Macrora) often reported together with silicoflagellates. All of these taxa are the first reports for the Central Paratethys. Silicoflagellate species composition is consistent with the datums derived from other fossils. Silicoflagellates, marine diatoms and archaeomonads suggest a neritic depositional environment.

Transferring Peucedanum macilentum (Apioideae, Apiaceae) to Ligusticopsis based on morphological and molecular evidences

Peucedanum macilentum is a less-studied species endemic to China, previously assigned to the genus Kitagawia. To elucidate its taxonomic affinity, morphological and molecular analyses were conducted. Morphologically, Peucedanum macilentum resembles Ligusticopsis species in several diagnostic characters of the stem base clothed in fibrous sheaths, pinnate bracteoles, conspicuous calyx teeth, strongly dorsally compressed fruits, as well as more vittae on the commissure. Phylogenetic analyses of nrDNA ITS and plastome sequences further reveal that P. macilentum is distant from Kitagawia but nested within Ligusticopsis. Therefore, in the basis of the morphological and molecular evidences, Peucedanum macilentum is transferred into Ligusticopsis and a new combination, Ligusticopsis macilenta, is proposed.

Macro- and micromorphology of Carex pauciflora-type fossils (Cyperaceae) from Europe and Siberia reveals unexpected affinity to Carex sect. Cyperoideae

Elongated biconvex Carex fossil fruits are relatively common in fossil assemblages, but they are of much uncertain taxonomic affinity. Three fossil-species have been erected to accommodate the materials from the respective type localities (C. klarae, C. paucifloriformis and C. paucifloroides) and a number of superficially similar-looking fossils were reported from other sites. The formerly proposed affinities mostly pointed to the extant C. pauciflora (subgen. Euthyceras) or Carex sect. Cyperoideae (subgen. Vignea), depending on the authors. But despite the similar superficial resemblance of the fossil remains to these not very closely related sedge taxa, other groups are also possible matches. We used a comparative approach employing stereomicroscope and SEM to analyze the affinities of several Old World “mummified” fossils (ca. 23 to 0.1 Ma) of elongated biconvex fruits. Several samples showed a fair preservation of previously unattested microscopic characters. In particular, one of them allowed us to detect an indirect record of fine silica body morphologies (impressions) on the periclinal walls, which permitted the sound taxonomic placement of the remains from the Miocene of Siberia as a Carex sect. Cyperoideae. In all the other fossils analyzed, the epidermal cell outline and the central position of the main silica body were sufficient to discard assignment to subgen. Euthyceras, despite a purported affinity to C. pauciflora reported in previous literature. In the absence of detailed information on silica bodies, epidermal cell (exocarp) details in fossil specimens do not seem to be determinant for the systematic placement. However, the addition of diagnostic style characters pointed to sect. Cyperoideae as the best match with the available information. Our data support a continued presence of Carex sect. Cyperoideae in the Old World since the Miocene, which candidates Eurasia as a possible place of origin for it, despite DNA-based reconstructions alone proposed North America. This study underlines the importance of detailed taxonomic studies to properly address the identity of fossils and unravel the biogeographic history of plants.

Siwalik sabrecats: review and revised diagnosis of Megantereon fossils from the foothills of the Himalaya.

The diagnosis of different fossil taxa in small collections from disparate geographical and temporal contexts is a common challenge in palaeontology. The likely number of morphospecies of the extinct sabretooth cat Megantereon is a classic example and subject of long-standing debate. While analyses of global fossil collections have provided insights and hypotheses, specimens from the foothills of the Himalaya-the Siwaliks-have been overlooked in recent treatments due to poor characterization and a confused taxonomic history. Here, this oversight is addressed. Craniodental fossils from the Siwaliks are revisited and their taxonomic status is reviewed. Morphological and metric characteristics are described, and qualitative and quantitative comparisons with congenerics are performed with published descriptions and datasets. The Lower Pleistocene Siwalik Megantereon are among the largest known forms in the genus. Advanced characteristics include reduced upper third premolars and long but comparatively narrow carnassial teeth. While dietary specialism can constrain morphological diversity, statistical analyses, including controls for body size effects, detected significant metric differences in the mandibles in comparison with congenerics. Within current paradigms, the status of Megantereon falconeri as a distinct morphospecies is upheld. A revised diagnosis is provided and the taxonomic affinities of M. falconeri are considered.

Redescription and molecular characterization of Loxocephalus luridus Eberhard, 1862 based on Czech populations: Implications for order Loxocephalida Jankowski, 1980.

The phylogenetic and taxonomic affinities of lineages currently assigned to the non-monophyletic ciliate order Loxocephalida Jankowski (1980) within subclass Scuticociliatia Small (1967) remain unresolved. In the current study, we redescribe the morphology of the type species, Loxocephalus luridus Eberhard (1862) based on two Czech populations and include the first scanning and transmission electron microscopy images of the species. We provide the first 18S rRNA gene sequences for L. luridus and consider its phylogenetic position. Our results support the separation of Dexiotricha from Loxocephalus; however, the former genus is recovered as non-monophyletic. The monophyly of genus Dexiotricha and that of Loxocephalus + Dexiotricha is rejected. Loxocephalus luridus, together with Dexiotricha species, nests within a fully supported clade with Conchophthirus species, long presumed to belong to the Pleuronematida. Haptophrya is recovered as sister to this clade. The monophyly of the Astomatia Schewiakoff (1896) including Haptophrya is rejected. No clear morphologic synapomorphy is identified for the fully supported clade consisting of Haptophrya, Dexiotricha, Loxocephalus, and Conchophthirus.

Neea bradeana (Nyctaginaceae: Pisonieae), a new species with whorled leaf arrangement from the Atlantic Forest of Southeastern Brazil

Neea bradeana is here described for the Atlantic Rainforest of Southeastern Brazil. This new species had been confused for decades with N. verticillata, the type species of the genus which is described for Peru. N. bradeana is characterized by its unbranched shrubs with whorled sessile or short-petiolate leaves and erect-congested inflorescences. This species is here described and illustrated; remarks on taxonomic and morphologic affinities, distribution map, and conservation assessment are also provided.

The dinosaurs that weren't: osteohistology supports giant ichthyosaur affinity of enigmatic large bone segments from the European Rhaetian.

Very large unidentified elongate and rounded fossil bone segments of uncertain origin recovered from different Rhaetian (Late Triassic) fossil localities across Europe have been puzzling the paleontological community since the second half of the 19th century. Different hypotheses have been proposed regarding the nature of these fossils: (1) giant amphibian bones, (2) dinosaurian or other archosaurian long bone shafts, and (3) giant ichthyosaurian jaw bone segments. We call the latter proposal the 'Giant Ichthyosaur Hypothesis' and test it using bone histology. In presumable ichthyosaur specimens from SW England (Lilstock), France (Autun), and indeterminate cortical fragments from Germany (Bonenburg), we found a combination of shared histological features in the periosteal cortex: an unusual woven-parallel complex of strictly longitudinal primary osteons set in a novel woven-fibered matrix type with intrinsic coarse collagen fibers (IFM), and a distinctive pattern of Haversian substitution in which secondary osteons often form within primary ones. The splenial and surangular of the holotype of the giant ichthyosaur Shastasaurus sikanniensis from Canada were sampled for comparison. The results of the sampling indicate a common osteohistology with the European specimens. A broad histological comparison is provided to reject alternative taxonomic affinities aside from ichthyosaurs of the very large bone segment. Most importantly, we highlight the occurrence of shared peculiar osteogenic processes in Late Triassic giant ichthyosaurs, reflecting special ossification strategies enabling fast growth and achievement of giant size and/or related to biomechanical properties akin to ossified tendons.