This study examines the brain morphology of Pliocene specimens of the South American Echimyidae rodent Eumysops chapalmalensis through virtual endocasts and comparisons with extant members of the family. Shape variation is analysed through geometric morphometrics, and the relative sizes of the brain and its components are estimated using phylogenetic regression models. The influence of phylogeny and

Cryptic lineages require identification and delimitation to guide their conservation and management. In the absence of type material that can be genotyped, designating a neotype becomes necessary: such is the case for Aporrectodea trapezoides and Octodrilus complanatus. These widely distributed earthworms are very common in Mediterranean habitats and harbour cryptic lineages. Specimens from the type

The fossil reptile Milleretta holds a prominent role in phylogenetic analyses of early reptile relationships. It has often been used as the sole marker for the anatomically diverse middle to late Permian Millerettidae, a clade that has been hypothesized as the earliest diverging parareptiles and therefore only distantly related to the reptile crown group. However, the anatomy of Milleretta remains

The present study deals with the intricate phylogenetic relationships within an important clade of the caridean shrimp family Alpheidae, which includes the genera Salmoneus, Deioneus, and Triacanthoneus. Using molecular data from four genes (16S, 18S, COI, and H3), we herein provide the most comprehensive phylogenetic hypothesis for this alpheid clade, with 161 terminals representing 117 ESUs, i.e

Giant short-faced bears (Arctodus simus) were the largest carnivoran of Pleistocene North America and are one of the most extensively studied extinct megafaunal species from the continent. Smaller and larger forms of A. simus have previously been recognized and are sometimes considered subspecies (A. s. simus and A. s. yukonensis, respectively). However, researchers have also proposed that this size

Gastrotricha encompass a diversity of free-living micrometazoans typically associated with aquatic or semi-aquatic environments. The discovery of a gastrotrich species in limno-terrestrial habitats challenges existing taxonomic classifications and expands our understanding of their ecological diversity. This study describes Dendroichthydium ibyrapora gen. et sp. nov., a new gastrotrich from epiphytic

Piatnitzkysaurus floresi is a theropod dinosaur from the Cañadón Asfalto Formation (Chubut Province, Argentina) and one of the few Early Jurassic tetanurans known worldwide. This species is known from two specimens and plays a key role in our understanding of the early evolution of tetanuran theropods. Nevertheless, the published information about its postcranium is limited to the original description

Among the five known Trogidae genera, Polynoncus is the only one endemic to South America. Although the systematics within Trogidae is well established, the evolutionary relationships among Polynoncus species remain poorly understood. Here, we conducted a phylogenetic analysis based on maximum parsimony, using the equal and implicit weighting algorithm with all characters, in TNT v.1.5 software. The

Saicini comprise 24 genera and 147 species worldwide. Here, we include additional taxa and characters to the morphological dataset of Castro-Huertas and Melo (2023) into a new one composed of 181 characters, which was analysed cladistically with 63 terminals, comprising 18 genera (75% of the generic diversity), 49 species of Saicini, and 12 outgroups. Saicini was recovered as monophyletic, with Carayonia

Noblella is a genus of 17 recognized nominal species of ground-dwelling, direct-developing frogs. It consists of two clades that do not form a monophyletic group: a northern clade from northern Peru, Ecuador, Colombia, and Brazil and a southern clade from southern Peru and Bolivia. Herein, we present a systematic review of Noblella with emphasis on the northern clade, including a new phylogeny based

The extinct scorpion family Chaerilobuthidae Lourenço and Beigel, 2011, endemic to Burmese amber, was initially established due to its unique pedipalp trichobothrial pattern related to the Type A and Type B patterns of families Buthidae C.L. Koch, 1837 and Chaerilidae Pocock, 1893, respectively. The present contribution describes 11 new specimens, representing seven species of Chaerilobuthidae from

The evolutionary relationships among genera within the nudibranch family Discodorididae remain poorly understood, with comprehensive molecular studies still largely absent. Discodoris, the most species-rich genus within this family, has historically represented a wastebasket taxon where species with ‘discodoridid’ morphology were placed. In this study, we present molecular data to evaluate the taxonomic

We revise the spider genus Cybaeolus Simon, 1884, endemic to Chile and Argentina, including three species, Cybaeolus delfini (Simon, 1904), Cybaeolus pusillus Simon, 1884, and Cybaeolus rastellus (Roth, 1967). The genus Clitistes Simon, 1902 is synonymized with Cybaeolus, and its type species Clitistes velutinus Simon, 1902 is synonymized with Cybaeolus pusillus. We provide a phylogenetic analysis

Neopilina galatheae Lemche, 1957, first collected in the 1950s, was presented as a critical species for understanding animal evolution, particularly in the context of segmentation. Decades later, we have now revisited this iconic species using a newly collected specimen and modern micro-computed tomography (µCT). A comprehensive 3D digital model of the internal anatomy of N. galatheae revealed new

Liogenys is a neotropical genus widely distributed in South America and characterized by rhizophagous feeding habits. Taxonomy survey of Liogenys from Chile revealed a species complex consisting of L. palpalis, L. obesula and an undescribed morphotype. Morphological data alone are not sufficient to distinguish between them. The three-species hypothesis was tested using phylogenetic and preliminary

Most adaptive traits evolved multiple times independently, but the conditions of their evolution remain obscure. Here I examine the origins of columellar folds, spiral ridges on the axial wall of the interior of many gastropod shells, in both extant and fossil gastropods. Analyses indicate that these features arose at least 46 times, primarily in caenogastropods and heterobranchs. Columellar folds

Red-blooded neritimorph gastropods in the subfamily Shinkailepadinae are specialists of chemosynthesis-based ecosystems, with the most diverse genus Shinkailepas endemic to deep-sea hydrothermal vents. All described Shinkailepas species have so far been from the western Pacific, despite reports of unidentified Shinkailepas from the Indian Ocean in the literature for decades. Here, we use an integrative

We reconsider the biodiversity and biogeography of Paralaoma servilis—believed to be one of the most globally invasive exotic land snails—through integrative empirical revision. Phylogenies obtained from nDNA (ELAV, ddRAD genomics) and mtDNA (COI) demonstrate that the current classification is in error, with there being at least five distinct species within P. servilis s.l. The P. servilis group as

Columbidae (the pigeon and dove family) are a speciose clade of non-passerine birds with a near global distribution. Recently, Young et al. (2024) undertook an evaluation of the systematics and nomenclature of the Dodo and its sister species the Rodrigues Solitaire. Therein, they also investigated the validity of columbid family-group names. Since publication, we have been made aware of corrections

The intriguing origin and distribution of subterranean amphipods of the family Niphargidae, particularly in north-western Europe and the British Isles, were heavily influenced by Pleistocene glaciations, which obscured most ancient events. The discovery of a new species in Brittany (described herein as Niphargus quimperensis sp. nov.) that is closely related to two tiny endemic species of the British

Local adaptation to environmental heterogeneity across a landscape can result in population divergence and formation of lineages. On Guadeloupe Island, the active volcano, La Grande Soufrière, peaks at 1460 m a.s.l., with rainforest at low elevations transitioning to humid savannahs at high elevations. Two endemic sister species of Eleutherodactylus frogs are co-distributed across this habitat gradient

Noasaurus leali is a small (~2 m) carnivorous theropod and the nominal genus of the clade Noasauridae, one of the two radiations of abelisauroid ceratosaurs predominantly present in the Southern Hemisphere during the Mesozoic. This eponymous theropod from the Maastrichtian Lecho Formation of Salta, Argentina, is known from an incomplete skeleton of which the strongly curved manual ungual is the most

Tardigrade taxonomy is undergoing a turbulent phase of reclassifying various species that have previously been gathered within large wastebasket genera, such as Diphascon or Hypsibius. The application of genetic sequencing, paired with detailed analysis of fine morphological features in 3D using scanning electron microscopy, allow for revealing new phenotypic characters used in systematics. At the

Venom is a metabolically expensive secretion used sparingly in a variety of ecological contexts, most notably predation and defence. Accordingly, few animals employ their toxins from a distance, and venom-squirting behaviour is only known from select taxa. In scorpions, species belonging to two genera are known to spray venom when threatened, and previous work in Parabuthus transvaalicus shows that

The Galapagos finches represent a rapid radiation of birds across the remote oceanic archipelago that vary morphologically, behaviourally, and genetically. The level of diversity and rapid rate of speciation have created taxonomic difficulties in resolving phylogenetic relationships. While much of the phylogeny has recently been clarified with modern genomic methods, some of the diversity has been

Organisms in adaptive radiations are able to diversify and colonize multiple environments. Frequently, the evolution of key adaptations enables organisms to confront novel environmental challenges, promoting diversification. Here, we studied desert colonization in the Liolaemus radiation. We assessed the patterns of climatic niche evolution in the L. nigromaculatus section, one Liolaemus clade inhabiting

Dinosaurs arose in the Late Triassic and diversified during the subsequent periods of the Mesozoic Era. The oldest unequivocal dinosaurs come from Carnian deposits of Brazil, Argentina, India, and Zimbabwe, with sauropodomorphs representing the bulk of this record. Saturnalia tupiniquim was described from Brazilian strata in 1999 as the first Carnian member of that group. Although several new species

The classification and phylogenetic position of Haplotaxidae, an enigmatic family of clitellate worms, have long been discussed. We estimate the phylogeny for Clitellata as a whole, using a taxon sample adhering to current definitions of Haplotaxidae and including species attributable to Haplotaxis, plus a representation of other clitellates. Sequences of five markers, 4087 bp in total, were analysed

Neurocranial features appear to be phylogenetically informative and key in assessing the still contentious relationships within Crocodylomorpha. However, the braincases of many non-crocodylian taxa are incompletely studied precluding the assessment of evolutionary modifications at the base of Crocodylia. Here, we describe the braincase osteology and neuroanatomy of the paralligatorid crocodylomorph

Defining species boundaries may result challenging and has been a widely debated issue in the last decades. In cases of cryptic or “pseudocryptic” species, molecular approaches can be a valuable tool to provide taxonomic hypotheses and significantly complement morphological taxonomy. Here, two mitochondrial and one nuclear markers were used to study the phylogenetic relationships within the genus Tiroloscia

Cerambycidae (Coleoptera: Chrysomeloidea) are a widely distributed group of insects with significant economic importance. Despite substantial efforts and some advancements in inferring the phylogeny of Cerambycidae, high-level phylogenetic relationships within the family, including subfamily and tribe-level classification, remain contentious. In this study, we performed whole-genome sequencing on a

The Cyclophoroidea are a group of land snails possessing an operculum that seals the aperture when the snail withdraws its body into the shell. Several groups have developed snorkel-like tubes, which are open at their outer ends, for gas exchange when the operculum closes the aperture. The tube of the cyclophorid subfamily Alycaeinae is, however, closed at its outer end. Recent investigations revealed

Etymology is a key component in zoological nomenclature, often carrying key information for an organism. Greek and Latin languages have been used for centuries in synthesizing zoological names. However, there are surprisingly few studies about each language’s contribution, which is crucial for avoiding misunderstandings around names’ meaning and origin. This study examined the publications that described

The evolution of flower-visiting behaviour in pollen wasps remains poorly investigated. The females of oligolectic Celonites species show two fundamentally different behavioural patterns for pollen uptake from Heliotropium flowers with a narrow corolla tube. They remove pollen from the concealed anthers either with their forelegs or with their proboscis. Single-frame video analysis revealed that pollen

Diamesa is a cold-adapted genus of Diptera: Chironomidae colonizing cold freshwaters of the Northern Hemisphere and East Africa. Global warming and glacier shrinkage are threatening their survival. In this work, we aimed to provide new insights into taxonomical gaps and phylogeny of Diamesa species from the Pyrenees, Alps, and Karakorum mountains to understand the colonization processes better and

Within armadillos, two clades are currently recognized: Chlamyphoridae and Dasypodidae. Major evolutionary processes of Chlamyphoridae are linked to the main environmental and climatic events that occurred in South America in the Cenozoic. More precisely, the Euphractinae reached a high diversity concomitant with the cooling period of the Late Miocene–Pliocene. One of the largest euphractines is Macrochorobates

Madagascar and the Comoros Archipelago are inhabited by freshwater planarians of the genus Dugesia characterized by a unique morphotype with long and pointed auricles, which were traditionally ascribed to only one species, Dugesia milloti. Collections of new specimens of these long-eared freshwater triclads enabled us to examine these worms in more detail than previously had been possible and, thus

Awareness of pressures on subterranean habitats and their associated groundwater-dependent ecosystems has increased recently. Subterranean fauna provide critical services and can act as bioindicators; however, a significant portion of this diversity is unknown. The family Bathynellidae are neglected taxa of tiny subterranean crustaceans, with only 112 species described in 36 genera and three subfamilies

The microscopic members of the genus Urodasys are easily recognizable due to their exceptionally long tail. There are 17 described species within this iconic genus, each distinguished by various sexual organ arrangements and reproduction modalities, including the sole known ovoviviparous gastrotrich species. The remarkable variety in reproductive characteristics has captured the interest of researchers

Species in the beetle family Histeridae exhibit numerous defensive adaptations, from a generally compact and spheroid body shape to retractable tarsi, legs, heads, and antennae. Modes of antennal concealment are particularly variable, underscoring the importance of protecting these essential sensory structures. Understanding the evolution of these morphological features has been hindered by a weak

The anuran locomotor system integrates traits that are influenced by phylogenetic, ecological, and development constraints. Given their significance to locomotion, we studied terminal phalange morphology in the Hyloidea group. We aim to deduce if morphological variability stems from phylogenetic, ecological, or life-cycle constraints. We explore the influence of size on variation and assess if evolutionary

South Africa is currently home to a highly diverse tortoise assemblage whose evolutionary history has been investigated mostly as a result of molecular studies. The fossil record is of little help because the remains of extant taxa are relatively recent, and only three extinct species, of uncertain relationships, have been described so far. An Early Pliocene extinct species of the currently monotypic

The Zambezi grunter, Parauchenoglanis ngamensis, is currently distributed across four (sub)basins in southern and south-central Africa, namely the Okavango, upper Zambezi, Kwanza, and Kasai. The present study used a combination of molecular (barcoding), colour pattern, and other morphological data to explore the possible existence of hidden species diversity within this species. Based on the available

Research interest in the diversity and evolutionary history of herring-like fossils (subcohort Clupei) has increased in recent decades. However, little is known about the relationships between fossils assigned to Clupei, particularly those that are demonstrably related to extant herring-like members of the order Clupeiformes. To help bridge this gap, we present a new morphological phylogeny that includes

About 300 valid species are classified within the order Rajiformes, the largest group of chondrichthyans. The monophyly of this order is highly supported by morphological and molecular inferences, but little is known about the mandibular, hyoid, and hypobranchial muscles of its members. This study aims to describe and illustrate the morphological variation in mandibular, hyoid, and hypobranchial muscles

Fish skulls are often highly kinetic, with multiple linkage and lever systems powered by a diverse suite of muscles. Comparative analysis of the evolution of soft-tissue structures in the fish skull is often limited under traditional approaches, while new imaging techniques like diceCT (diffusible iodine-based contrast-enhanced computed tomography) allow for high-resolution imaging of muscles in situ

Synodontis Cuvier, 1816 is a species-rich group of African catfishes. Prior to this analysis, 13 species of Synodontis were recognized from Lake Tanganyika and its tributaries, composing the only extant lacustrine radiation of the genus, with a unique origin of obligate brood parasitism among all fishes. Species differentiation and phylogenetic relationships of this group remained largely unresolved

Cryptic species are black boxes of taxonomy and need to be addressed with an integrative taxonomic approach. Simulium (Diptera: Simuliidae) may contain a substantial amount of cryptic species diversity due to its large cross-continental distribution and habitat-based canalization in taxonomic characters. Except for Simulium sergenti, the following six species Simulium equinum, Simulium paraequinum

The predatory cladoceran Bythotrephes is one of North America’s most successful and impactive invasive species in freshwater plankton communities. The taxonomic status of the genus Bythotrephes Leydig, 1860 (Crustacea: Cladocera: Cercopagididae) has remained unclear and a subject of intensive debate for over 150 years. We applied an integrative taxonomy approach with multi-gene analysis (mitochondrial

We analysed phylogenetic relationships within a major clade of Cyprinodontiformes (Teleostei) that includes five families of North American killifishes. We used DNA sequences from five genes for 130 species, with four fossil calibrations and three secondary calibrations, to generate a time-calibrated phylogeny. We estimated diversification rates, ancestral areas, and ancestral habitats for each node

The Late Quaternary fossil record indicates that formerly in the North Atlantic volcanic Macaronesian archipelagos (Azores, Madeira, Selvagens, Canary Islands, and Cape Verde) there was a higher avian diversity, including numerous now extinct species. Currently, only three gadfly petrels (genus Pterodroma) remain in two archipelagos: the Fea’s petrel, Pt. feae, in Cape Verde (islands of Santiago, Fogo

The Palpimanidae are one of five extant Palpimanoidea families that occur mainly in South America and Africa, although there are lineages in Madagascar, islands of the Indian Ocean, and parts of Asia. Here we examine the role of plate tectonics in shaping the distribution of Palpimanidae. We perform molecular sequencing via target enrichment, which makes use of fragmented DNA, because most specimens

The Marquesas Islands harbour numerous underwater caves, with different geomorphologies and a rich diversity of invertebrates dominated by sponges. However, although calcareous sponges are known to be abundant in cryptic habitats, only one of the four species reported from Marquesas was found in caves. Hence, our objective was to study the diversity of cave-dwelling calcareous sponges from the Marquesas

Anuran larvae are characterized by an extensive array of specialized oral structures that allow them to both graze on substrates and suspension feed with great efficiency. Diversity in these feeding structures accounts for significant diversity of anurans. Herein we describe an astonishing novel buccopharyngeal morphology in six larvae of ‘sand-eating’ tadpoles of the Mantellidae genus Mantidactylus

The Triassic was a key period in the evolution of vertebrates, and reptiles in particular, giving rise to a plethora of successful lineages, some of which are still extant. One of the groups that flourished during the early Mesozoic were the tanysaurians (Archosauromorpha: Tanysauria). They had elongate neck vertebrae that in some genera reached extreme proportions. Here, we provide the first comprehensive

Arthroleptidae are an ecologically diverse group of sub-Saharan frogs. Arthroleptid tadpoles predominately occur in slow flowing to torrent waters. Their musculoskeletal system and the relationship between tadpole morphology and lifestyle are poorly understood. Here, we investigated the cranial morphology of four arthroleptid tadpoles occurring in different microhabitats: Leptopelis parkeri, Astylosternus

The Kem Kem Group is a lowermost lithostratigraphic unit from the Upper Cretaceous that extends along the border between Algeria and Morocco, in the northern region of Africa. This geological unit has yielded several tetrapod fossils, including a well-represented assemblage of theropod dinosaurs, after more than eight decades of research. Here, we report new occurrences of spinosaurid theropods from

Early Cretaceous ichthyosaurs were globally distributed pelagic marine reptiles, but many remains are fragmentary, creating a Northern Hemisphere diversity bias. A rich Hauterivian locality near the Tyndall Glacier inside Torres del Paine National Park in southern Chile yields important new data regarding ichthyosaurian diversity along the Pacific margin of Gondwana. These new data will contribute

We here describe Terastiodontosaurus marcelosanchezi, a new amphisbaenian genus and species from the Eocene of Chambi, Tunisia. Using micro-computed tomography (μCT), we document the peculiar anatomy of the new taxon, which is characterized by extreme dental morphology, including one massive tooth on the maxilla and dentary, flat cheek teeth, and an array of other diagnostic features that readily differentiate

In this study, we conduct a morphological integrative analysis, using traditional techniques and micro-computed tomography imaging, on Septibranchia species. Specimens deposited in malacological collections and samples collected aboard the research vessels Puerto Deseado and Austral off Mar del Plata (~36°S), San Jorge Gulf (~46°), and Marine Protected Area Namuncurá/Burdwood Bank area (~54°S), at