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  • 16 Reads
Two new combinations in Oxossia (Passifloraceae s.l., Turneroideae)
Published: 01 December 2025 by MDPI in The 1st International Online Conference on Taxonomy session Plant Taxonomy

Recently, a new genus segregated from Turnera L. (Passifloraceae s.l., Turneroideae) was described to accommodate a group of species that are phylogenetically well-supported. This new genus, Oxossia L.Rocha, was established to reflect these evolutionary distinctions within the subfamily Turneroideae. Although Oxossia does not present clear autapomorphies, it appears to be morphologically cohesive and can be recognized by a combination of characters that support its recognition as a separate evolutionary lineage. These diagnostic features include conspicuous stipules, flowers arranged in congested inflorescences, typically white corollas, pilose styles and stamens, and stamens that are basi-dorsiventrally adnate to the floral tube. Concomitantly with the establishment of Oxossia, we describe two species from northeastern Brazil, Turnera acangatinga Costa-Lima & E.C.O.Chagas and T. ibateguara Costa-Lima & E.C.O.Chagas, which exhibit morphological traits consistent with the circumscription of this new genus. Both species present unique reproductive characters that align them with the diagnostic features of Oxossia, including distinctive floral structures that set them apart from typical Turnera species. To update the taxonomy of this group and reflect the currently accepted circumscription, we followed the criteria of the International Code of Nomenclature for algae, fungi, and plants, and formally propose the transfer of these species to Oxossia. This results in the new combinations Oxossia acangatinga (Costa-Lima & E.C.O.Chagas) Costa-Lima & E.C.O.Chagas comb. nov. and O. ibateguara (Costa-Lima & E.C.O.Chagas) Costa-Lima & E.C.O.Chagas comb. nov.

  • Open access
  • 69 Reads
Taxonomic Insights into Nigerian Terminaliinae (Combretaceae) Based on Molecular and Morphological Evidence: Implications for generic circumscription
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Published: 01 December 2025 by MDPI in The 1st International Online Conference on Taxonomy session Plant Taxonomy

The circumscription of the subtribe Terminaliinae (Combretaceae) has been a subject of controversy. Its generic phylogeny has also not been clearly elucidated. In this study, the taxonomic position of the Nigerian Terminaliinae taxa was revised based on the morphology and combined analyses of molecular markers to document taxonomic information on classification of Terminaliinae and ascertain the morphological and phylogenetic relationships among the members. Phylogenetic relationships were inferred using three DNA regions: ITS, rbcL and trnH-psbA sequences, while the morphological studies included the analysis of macromorphological and micromorphological features of all Terminaliinae species in Nigeria. The findings support the inclusion of Anogeissus leiocarpus in Terminalia while also retaining the Conocarpus and Pteleopsis species within Terminaliinae. The relationships between Terminalia and other Terminaliinae taxa remain unresolved based on only one molecular marker. The phylogenetic studies showed that trnH-psbA has better species discrimination efficiency than rbcL and ITS genes due to its highly variable nature. Transition/transversion bias test corroborated this finding as trnH-psbA showed higher bias (2.714) than rbcL (2.225) and ITS (2.126). The outcomes from the morphological studies indicated significant differences between Anogeissus, Conocarpus, Pteleopsis and Terminalia. However, the seed shape, inflorescence position, number of petals, stamens and fruit-wings, extrafloral nectaries, epidermal cells shape and anticlinal walls are useful characters for the identification of some Terminaliinae species. The morphometric analysis and molecular data suggest that Anogeissus and Terminalia could have evolved from a common ancestor. Accumulation of morphological differences and acceleration of the evolution of Anogeissus and Terminalia were more intensive than in other Terminaliinae species and this could probably be synchronized with adaptation to different climatic conditions. The phylogenetic relationships between the taxa were best resolved with Maximum Likelihood (ML) and Neighbour-joining (NJ) in combination with nrDNA ITS and chloroplast (rbcL and trnH-psbA) genes, phylogenetic trees constructed with combined ITS, rbcL and trnH-psbA revealed monophyletic nature of origin for the three genera: Anogeissus, Pteleopsis and Terminalia, while Conocarpus serves as a sister group to all remaining genera and species in the subtribe Terminaliinae. Bootstrap support and Bayesian posterior probability were found to be higher in trnH-psbA topologies than that of rbcL and ITS. The dendogram and phylogeny of Terminaliinae revealed nested grouping of the Anogeissus species within Terminalia, and we suggest that all genera of Terminaliinae, with the exception of Conocarpus and Pteleopsis should be included in an expanded circumscription of Terminalia. Morphological and molecular trees revealed congruence in the number of main clades resolved and an indented dichotomous key was produced for easy identification of species.

  • Open access
  • 20 Reads
Nomenclature is the scientific language of Taxonomy, and you already know everything about it
Published: 01 December 2025 by MDPI in The 1st International Online Conference on Taxonomy session "Paleotaxonomy"

Nomenclature and Taxonomy are often considered boring topics of research, whereas even some researchers consider Nomenclature not to be a scientific discipline at all. Others believe that Taxonomy needs a major image change to attract interest from modern scientific audiences. In this contribution, I rebrand Nomenclature and Taxonomy as parts of the same scientific discipline, following Schneider’s (2009) scheme. Furthermore, I focus on the role of taxonomists in promoting the importance of nomenclature and taxonomy to younger scientific audiences and teaching these techniques in a way that supports the entire discipline. My own experience with Nomenclature and Taxonomy teaching is that it usually focuses on the most complicated and confusing exceptions where the Code did not work, instead of focusing on teaching the main part of the discipline that does work well. Even in those cases, teachers present it with excessive terminology and complex terms that may discourage the student or young researcher. Here, I propose a new, simple method for teaching the key concepts of nomenclature and taxonomy — availability, validity, homonymy, synonymy, coordination, and spelling — using analogies that people are familiar with their daily lives: how a computer archives its files. With this analogy, the teacher can deliver the main concepts of nomenclature and taxonomy in a few minutes.

  • Open access
  • 39 Reads
Uncovering hidden diversity in Iberian freshwater fossil snails: an integrative approach to Horatia schlosseri (Royo-Gómez, 1922) (Gastropoda: Hydrobiidae)
Published: 01 December 2025 by MDPI in The 1st International Online Conference on Taxonomy session "Paleotaxonomy"

The classification of Hydrobiidae Stimpson, 1865, a diverse family of freshwater gastropods, is hindered by their minute size and simplified shell morphology, resulting in a lack of diagnostic features in fossils. This leads to taxonomic ambiguities and the concealment of cryptic diversity, as seen in Horatia schlosseri (Royo-Gómez, 1922), a species frequently reassigned without consistent analysis. An integrative taxonomic approach is thus essential for accurate fossil identification and systematic resolution. To assess morphological variation within H. schlosseri, we applied geometric morphometrics (GM), analyzing shell shape across 163 specimens from eight Iberian localities. These included syntypes of H. schlosseri, type material of Horatia klecakiana (type species of Horatia), and paratypes of the similar genus Tarraconia. Shells were digitized with 18 landmarks/semi-landmarks and analyzed using Procrustes superimposition, Linear Discriminant Analysis (LDA), and ANOSIM.GM analysis revealed four distinct morphotypes within the H. schlosseri complex. Specimens from Alcalá del Júcar, previously attributed to H. schlosseri, clustered statistically with Tarraconia (ANOSIM p > 0.05) and were reassigned as Tarraconia sp. 1, further supported by the presence of a diagnostic varix. Two new cryptic species were also identified: Horatia sp. 1 (La Hontanilla Spring, Cuenca) and Horatia sp. 2 (Concud, Teruel), both from localities historically linked to H. schlosseri. Our results highlight the limitations of traditional morphological methods in Hydrobiidae systematics and emphasize the value of GM in revealing cryptic diversity. This study underscores the need for a comprehensive revision of Iberian caenogastropod fossils using integrative, quantitative approaches.

  • Open access
  • 23 Reads
Re-evaluation of the taxonomy of Compsemys: an enigmatic turtle from around the Cretaceous–Paleogene boundary
Published: 01 December 2025 by MDPI in The 1st International Online Conference on Taxonomy session "Paleotaxonomy"

Compsemys is an enigmatic turtle first described over 150 years ago. Its taxonomic placement has been in flux, with many of its referred species being removed. For the last three decades or so, Compsemys victa has been the only accepted North American species. New fossil specimens collected from the Paleocene of North America suggest that a re-evaluation of its taxonomy is in order, calling into question the long-held belief that only one species of Compsemys is valid in North America. Paleocene specimens are far more complete than the holotype of C. victa, but have all been referred to this species based on similar surface sculpturing. Differences between Cretaceous and Paleocene fossil material suggest multiple species of Compsemys are valid. In addition to the genotypic species C. victa, two Paleocene species (Compsemys puercensis and C. torrejonensis) are valid based on morphological differences of the carapace and plastron, particularly aspects of scute sulci (such as those of the humerals, pectorals, femorals, and vertebrals), the neurals, and some aspects of the shapes of the plastral lobes. North American Compsemys survived the Cretaceous–Paleogene mass extinction. Rather than being a monospecific genus, this taxonomic re-evaluation of Compsemys shows how it became more diverse during the early Paleocene period, at least in the American southwest, perhaps exploiting the loss of numerous other taxa during the K-Pg mass extinction event. Not only does this re-interpretation of Compsemys' taxonomy suggest an increase in diversity of North American compsemydids, but it also leads to the possibility of anagenesis within the genus during the Late Cretaceous and Paleocene periods, at least in the American southwest.

  • Open access
  • 76 Reads
The female of the first Cretaceous velvet water bug Archaeohebrus alius Zhang, Ren & Yao 2024 (Heteroptera: Hebridae)
Published: 01 December 2025 by MDPI in The 1st International Online Conference on Taxonomy session "Paleotaxonomy"

Recently, the first Cretaceous velvet water bug (Heteroptera: Hebridae), Archaeohebrus alius Zhang, Ren & Yao 2024, was described from Myanmar amber, based on one male specimen. In the present contribution, we report the finding of the first female of this species, based on one specimen collected in the same area. The amber piece containing the studied fossil originated from Noije Bum, near Tanai Village Hukawng Valley, Kachin State, northern Myanmar. It is dated as the earliest Cenomanian, mid-Cretaceous (98.79 ± 0.62 Ma). The female studied has an elongated body (2.28 times longer than wide) with a subtriangular head and hexagonal pronotum. The hemelytra are fully developed, bearing three closed cells and almost reaching the end of the abdomen. Finally the external genitalia has an eightht abdominal segment strongly concave towards the middle; the ninth abdominal segment is elongated and looks subtrapezoidal in lateral view; the first valvifer is well developed and has an isosceles triangle shape in lateral view; the three valvula are visible and well developed, subrectangular in lateral view; and the ovipositor is well esclerotized and resting inside the valves. In general, the female looks similar to the male, but is a little more slender, with the head and pronotum more stylized. This dimorphism has been observed in other modern Hebridae. In addition to the diagnostic characters shared with the male, the genitalia details observed in the female support the placement of this species in Hebridae.

  • Open access
  • 22 Reads
Taxonomic paleodiversity of the Marizal Formation (Aptian), Tucano Basin (NE Brazil)
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Published: 01 December 2025 by MDPI in The 1st International Online Conference on Taxonomy session "Paleotaxonomy"

The Amargosa Bed is a fossiliferous stratigraphic marker within the Marizal Formation, cropping out throughout the Tucano Basin in Northeastern Brazil. The fossil record of this unit was first reported during the 1650s and 1960s and currently comprises the remains of dinocysts (Subtilisphaera sp.), pollen (Schizaeaceae and Matoniaceae), plants (e.g., Bennettitales), invertebrates (e.g., caridean shrimps), vertebrates (Ophiopsidae, Amiidae, Aspidorynchidae, Cladocyclidae, Chanidae, and Clupavidae), as well as ichnofossils. These taxa are mostly indicative of a freshwater ecosystem. In light of continued excavation work, several new remains (35 scale impressions and approximately 200 articulated fish remains) have been retrieved and are currently being studied in order to assess their taxonomic identity and significance. So far, morphological approaches have shown the existence of three scale morphotypes, unlike those present in the previously described fish taxa—which were reevaluated and redescribed in detail. In the same sense, the articulated remains, still under study, can be assigned to at least four morphotypes with distinct proportions and morphological characteristics that hint at possible new taxa for the Amargosa Bed. These new findings, although still preliminary, highlight the biological paleodiversity of the unit—which likely comprises a higher number of taxa and ecological actors than previously thought.

  • Open access
  • 27 Reads
The morphology, phylogeny, and applications of Oligocene–Miocene Asterigerinoides (Foraminifera)
Published: 01 December 2025 by MDPI in The 1st International Online Conference on Taxonomy session "Paleotaxonomy"

Asterigerinoides guerichi guerichi (Franke 1912) is a well-known benthic foraminifer from the Chattian (upper Oligocene) of the North Sea Basin. The base of this classic Chattian is marked by an extensive bloom of A. g. guerichi, historically the ‘Asterigerina Horizon’ (recently the ‘Asterigerinoides guerichi guerichi acme event’). Despite its wide usage for stratigraphic purposes, the taxonomy and paleoecology of Asterigerinoides are quite obscure.

This study aims at identifying ecological traits, such as feeding strategies, which can elucidate the prolific abundance of A. g. guerichi during the Chattian and of A. guerichi staeschei during the Miocene, while simultaneously providing more insight into the phylogenetic relationships between A. g. guerichi, A. g. staeschei and Asterigerinoides frankei (mostly referred to as Asterigerina frankei) through literature study and comparison with collection material. We compared the morphology of A. g. guerichi, A. g. staeschei and A. frankei through optical microscopy and SEM, highlighting different features of these species. Ultimately, we also aim to create a revised taxonomy of Asterigerinoides and improve the utilization of A. g. guerichi as a stratigraphic marker.

Our observations on the morphological features of the three Asterigerinoides (sub)species, such as the equally biconvex test and teeth-like granules near the aperture, point towards a shallow marine habitat and epibenthic lifestyle with an endosymbiotic and potentially multitrophic feeding strategy. Stable isotope analyses are ongoing to evaluate these paleoecological interpretations towards paleotemperatures and possible vital effects caused by photosymbionts. The presence of keel pores, slit-like apertures surrounded by teeth-like granules and similar arrangements of secondary chambers observed in A. frankei, as well as A. g. guerichi and A. g. staeschei, led us to conclude that A. frankei is a member of the genus Asterigerinoides rather than Asterigerina. The insights presented here will improve our understanding of these species and their use as biostratigraphic markers.

  • Open access
  • 13 Reads
The plant–insect interactions in a newly discovered Middle Miocene locality in Kos island, Greece
Published: 01 December 2025 by MDPI in The 1st International Online Conference on Taxonomy session "Paleotaxonomy"

The Middle Miocene represents a critical interval in the history of European angiosperms and insects, particularly in the Mediterranean region, where climate change has influenced these communities, as the small amount of unevenly dispersed data indicate. Here, we present new findings from the island of Kos, Greece, where a rich assemblage of fossilized angiosperm leaves from the Middle Miocene provides novel data of plant–insect interactions at this transitional time interval. Palaeobotanical analysis confirms multiple angiosperm morphotypes, likely belonging to both deciduous and evergreen lineages. These fossils exhibit a diverse array of insect-mediated damage types (DTs), including margin feeding, hole feeding, skeletonization, mining, and galling structures.

Using the established Labandeira DT classification framework, we document over 10 discrete damage types, indicating a high level of functional feeding group diversity. Interactions’ relative richness and diversity are different among different leaf morphospecies, although Quercus and Acer, which are some of the most common leaf elements found in the assemblage, exhibit the highest diversity in DTs.

This study is the first to document such detailed insect–plant interaction data from the Miocene of Greece and contributes a new regional data point to the research on Cenozoic plant–insect associations. The diversity and specificity of the interactions observed underscore the ecological complexity of Miocene forests in the Aegean region. These results offer new insight into the vegetational and insect community dynamics of the region and support the use of trace fossil evidence as a proxy for reconstructing ancient insect diversity.

  • Open access
  • 14 Reads
Revisiting the fossil polypterid Polypterus faraou: taxonomic assessment based on cranial morphology
Published: 01 December 2025 by MDPI in The 1st International Online Conference on Taxonomy session "Paleotaxonomy"

Polypterus is an African freshwater fish genus comprising 13 extant species and 3 fossil species, including †P. faraou, which is based on a single articulated specimen from the Late Miocene (~7 Ma) of Chad. Recently, †P. faraou has been suggested to be conspecific with P. bichir, as its meristic values fall within the expected range of variation for P. bichir, which entirely encompasses the diagnoses of both taxa. In this study, we use X-ray tomography and three-dimensional reconstructions to generate new data on the cranial anatomy of †P. faraou and compare it with P. bichir in order to test the validity of the fossil species. Owing to the fossil’s exceptional preservation, all cranial regions and the pectoral girdle were described, either fully or partially. Regarding meristic characters, we corroborate that †P. faraou indeed falls within the range expected for P. bichir. However, we were able to distinguish the two species based on features of the opercular region and posterior ceratohyal morphology. Accordingly, we propose an emended diagnosis for †P. faraou, characterized by a proportionally longer ventral process of the preopercle, a higher subopercle that extends well beyond the mid-height of the opercle, an opercle with a more triangular outline, and a rounded posterior ceratohyal. Although these species show few morphological differences, we present here the first cranial osteological diagnosis for this genus, highligthing its importance for advancing the understanding of cranial morphology in polypterids.

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