Taxonomy, Volume 4, Issue 3 (September 2024) – 13 articles

The ascidian fauna of the Bahamas remains grossly understudied. Here, we examined specimens of the genus Clavelina collected from four Bahamian islands using morphological observations and genetic barcoding. Only three species of Clavelina have been previously reported in the Caribbean: C. picta, C. oblonga, and C. puertosecensis. Here, we report C. picta and three species new to science: C. rochae, C. pawliki, and C. erwinorum. C. picta and C. pawliki were found in the northernmost island surveyed, while C. rochae and C. erwinorum were particularly prevalent on the southeastern Bahamian islands. A complete review of genetic barcoding data and morphological characters of accepted Clavelina species was performed. The unique combination of in vivo coloration, morphological characteristics, haplotypes, and species distribution supported the establishment of three new species, significantly adding to the diversity of the genus Clavelina in the Caribbean. Full article

Past efforts to identify and characterize minimally monophyletic groups (microgenera) by deconstructing larger bryophyte genera successfully determined 10 microgenera comprising the moss family Streptotrichaceae. Thirty other microgenera have also been found in the moss family Pottiaceae. A microgenus consists of one ancestral species and, optimally, four immediate descendant species, each of which shares exactly the same ancestral traits. To determine if microgenera were common, evidence of these in larger genera was garnered from published estimates of species per genus in other groups and from molecular cladograms in the moss family Pottiaceae. Both classical mesogenera and cladistically enlarged macrogenera exhibited an internal granularity of one to five species, either as multiple species below the inflection point in the hollow curve of logarithmic graphs of species per genus or as small groups of molecular cladogram branches. Microgenera are basic units of evolution. The constancy of size and monothecy of traits in microgenera give them properties that larger taxonomic groups lack. Sequences of microgenera monophyletic are easily concatenated, adaptational changes may be directly determined, self-similarity across scale allows extended scientific inferences, and traits can be associated with survival across millions of years of environmental perturbation. Full article

The genus Strumigenys is the third most diverse among ants, having been reviewed globally. Despite this comprehensive review, new species are frequently discovered in most biogeographic regions. Here, we describe two new species, Strumigenys itannae sp. nov. and Strumigenys xoko sp. nov., based on material collected in the Amazon and the Brazilian Atlantic Forest. Additionally, new records for S. castanea, S. metrix, and S. orchibia are provided, expanding the known distribution of these species. We discuss morphological variation in S. schulzi and provide biological notes that indicate some species within the schulzi group are arboreal inhabitants. We provided an identification key for the newly described species as an amendment to the identification key for the Neotropical Strumigenys. Full article

A reliable character system is crucial to taxonomy and systematics, and it promises valid downstream inferences, e.g., estimates of diversity and disparity, reconstruction of evolutionary history, and even stratigraphic correlations. Modern taxonomy and systematics of extant cockroaches requires an integrative study involving multiple lines of evidence with emphasis on genital and reproductive characteristics and molecular data. In contrast, many fossil cockroach taxa published recently are based solely on forewings. Many studies have shown that forewing-based taxa are questionable. In order to find out how much of the phylogenetic signal we could ascertain from venational similarity, and how confident we could be, this study used forewing characters to reconstruct phylogenies of the genera of well-recognized family-group taxa. The intuitively reconstructed phylogeny of 75 extant genera failed to recover those taxa or their relationships. Parsimony analyses of various datasets all yielded strong polyphyly and chaotic relationships. In conclusion, the forewing of cockroaches is not a universally competent character system. The underlying causes are the complicated nature of veins and the limitations of current analytical techniques. The uncertainty in forewing-based taxonomy and systematics has been underestimated in the literature. Forewing-based fossil taxa warrant re-evaluation; some of them are herein deemed nomina dubia in their current state. Full article

The genus Cernotina Ross, 1938 is represented in the southeastern United States by three nominal species: Cernotina calcea Ross, 1938, Cernotina spicata Ross, 1938, and Cernotina truncona Ross, 1947. Of all Cernotina species, only the larva of C. spicata has been described to date. The goal of this paper is to describe, illustrate, and diagnose the larva of C. truncona using ecologically associated specimens. In addition, we used publicly available mitochondrial DNA barcoding data to evaluate the genetic relationships of these species. The larvae of Cernotina truncona can be distinguished from those of C. spicata by differences in setal placement and number on the meso- and metanota, mandibular morphology, head width, and distal setation of the tarsi. The ultrastructure of the anal claw is figured, highlighting the novel finding of small spines on the concave margin of a larva of Cernotina. With this new description, just the second described larva from this genus, only C. calcea remains unknown in the southeastern United States. The information provided herein enables the in-depth study of the ecology and life history of this diminutive caddisfly. Full article

Brachynemurus bowlesi, sp. n. is a newly discovered myrmeleontid from the Sonoran Province, the northernmost subtropical region of Mexico. The new species fits within the Brachynemurus versutus subgroup, which now includes five species, all of them occurring in Mexico and the central and western United States. The new species may be identified by characteristics of the internal male genitalia, especially by a roof-like mediuncus, as well as the basal part of the 10th gonostyli, with paired processes in an acute angle and a shield-like expansion more evident in the dorsocaudal view. The formerly proposed synonymy of Brachynemurus mexicanus Banks, under B. versutus (Walker), is herein reinstated and supported. Full article

A new monotypic genus of Prodidominae, Paleotoca gen. n., is proposed to include one cave species collected in a paleoburrow and ferruginous caves from Quadrilátero Ferrífero, Minas Gerais, Brazil: Paleotoca diminassp. n. (♂♀). The new genus is closely related to other Neotropical Prodidominae by sharing the classic claw tuft clasper. Paleotoca gen. n. is diagnosed by the absence of a dorsal abdominal scutum, a ventral parallel rows of strong spines on the tibia and metatarsus I–II, a lack of a conductor, a discrete median apophysis on the bulb and a bifid retrolateral tibial apophysis in the male palp, a posterior extension that is beak-shaped, and folds of a copulatory duct ventrally visible in the female epigyne. Like other Prodidominae species from caves, P. diminassp. n. is a troglobitic spider with morphological characteristics that indicate specialization to live in subterranean environments, including reduction in cuticular pigments, eye loss, heavy spination and trichobothria. Full article

The taxonomic status of butterfly rays within the genus Gymnura remains a subject of ongoing debate among researchers. Some authors recognize up to five valid species for the Americas, while others considered several to be synonyms, which has posed a persistent challenge. We aimed to shed light on this complexity by employing molecular operational taxonomic units (MOTUs) based on the mitochondrial gene cytochrome oxidase I (COI). Genetic sequences were obtained from fresh muscle tissue collected in the marine ecoregions corresponding to the type locality from all the nominal butterfly ray species distributed along the Eastern Tropical Pacific (ETP). Our results unveiled compelling findings; all the species delimitation models used consistently identified seven MOTUs for the American continent and an extra G. altavela MOTU restricted to Africa. In addition, our results and models exceeded the worldwide accepted interspecific threshold of 2.0%. Remarkably, our results support the taxonomic reinstatement of Gymnura afuerae (Hildebrand, 1946) as a valid species, with a range expanding into the ETP in the Southern Hemisphere. Similarly, our data support the recent suggestion of resurrecting Gymnura valenciennii (Duméril, 1865) as a valid species in the western Atlantic. These findings urge a reassessment of the conservation status and a comprehensive taxonomic revision of American butterfly rays. Full article

We present descriptions of two newly discovered species of Myxobolus (Myxobolidae) that infect Mugil curema: Myxobolus mundauensis n. sp. found in gills and Myxobolus patriciae n. sp. found in intestines. These descriptions are based on the morphology of myxospores, histological analysis, and sequencing of the small subunit ribosomal DNA (ssrDNA). The myxospores of both species differ in the width and length of their spore bodies, and their ssrDNA sequences showed a 10.6% difference. These findings support the identification of these parasites as distinct and previously unknown species. Phylogenetic analysis revealed a subclade consisting of species that parasitize Mugiliformes, with Myxobolus mundauensis n. sp. being closely related to Myxobolus maceioensis, and Myxobolus patriciae n. sp. being closely related to Myxobolus curemae. Our analysis aligns with previous research suggesting a strong correlation between host orders and phylogenetic patterns within the Myxobolidae family. Full article

Precise identification of diatom species is fundamental to correctly interpreting their roles in the marine ecosystems; the documentation of species records with illustrations is therefore essential to guarantee ecological works and the continuous use of compositional data in future works. We document the diatom flora in the Kuroshio Extension (KE) area of the northwestern Pacific. Samples were collected by sediment trap deployment from November 2017 to August 2018 and identified using light microscopy and scanning electron microscopy. Eighty-two taxa belonging to 17 families and 38 genera were documented with representative references, morphological dimensions, brief diagnosis, distribution, and short taxonomic comments. All of the taxa were divided into three distribution patterns (cold, warm, and eurythermal taxa) based on the previous distribution records; each group may be transported by the Oyashio and Kuroshio Currents, respectively. The mixed occurrence of cold- and warm-water species indicates that the KE area is a crossroads for them. A preliminary checklist was compiled from previous studies, incorporating our records, and 206 diatom taxa occurred in the northeastern path of the Kuroshio Current. The diatom flora in the KE area will be used to understand the hydrology of the Kuroshio Current in future work. Full article

Recently, based on light microscopy images, the tubercle structure on the seed surface of 100 Silene species was quantitatively described, including tubercle width, height, and curvature associated with general morphometric data. Curvature measures the rate of change of the tangent vector in a curve and can be calculated by the following methods described for Arabidopsis roots. Here, we apply curvature measurements to the SEM images of 40 Silene species from Türkiye, demonstrating that a quantitative analysis of tubercles can be made based on SEM images with similar results to optical photographs. The association of morphometric tubercle data allows for classification into six groups, five of them corresponding to described shapes: rugose (two groups), echinate, mammillate, and papillose, and a sixth group of tubercles plane on top. The curvature values vary between 20 and 200 mm⁻¹ and differ among the morphological tubercle types described. The correlation of curvature values with other general measurements and morphological seed characteristics is investigated. Tubercle quantification not only is a useful tool for Silene taxonomy, but also provides the basis for the analysis of the genetic control and developmental effects on tubercle structure and shape in the seed surface. Full article

Parasitic otitis is an inflammatory process that can affect the external to internal cattle ear, causing discomfort in animals, impairing performance, and even leading to animal death. The infection was initially associated with nematodes of the Rhabditis genus in tropical and subtropical regions. Currently, the nematode species described as associated with bovine otitis are Metarhabditis costai, Metarhabditis freitasi, and, more recently, M. blumi. It is worth highlighting that there is still a lack of robust information regarding the morphological details, ultrastructural aspects, and molecular biology data of these species. The Metarhabditis genus is composed of seven species and two more have recently been added. The objective of this study is to update the morphological data using advanced microscopy techniques to emphasize and clarify the main morphological differences between three species of Metarhabditis currently associated with parasitic otitis. Samples of inflammatory exudate were collected from four adult female Gir cattle (Bos taurus indicus) on a farm in Itabira, Minas Gerais state, Brazil. Specimens were analyzed using light microscopy and scanning electron microscopy. Two species, M. costai and M. freitasi, were morphologically identified, consistent with previous reports. Scanning electron microscopy revealed new structural characteristics of the nematode species involved in parasitic otitis compared with M. blumi obtained from the CGC Center. Significant differences were observed in the male posterior region, bursa, and tail. Molecular analysis was conducted to differentiate these three species, and it was observed that the species first associated with otitis formed distinct clusters compared to M. blumi. However, it is important to note that further studies are needed to genetically characterize species of the Metarhabditis genus. Full article

This study presents the first record of T. lindbergi from the southwestern Atlantic Ocean, based on specimens collected from the smalleye croaker Nebris microps Cuvier (Sciaenidae), off the coast of Maranhão Island, State of Maranhão, Brazil. Our approach included a morphological analysis complemented by DNA sequencing (28S, ITS2 rDNA, and cox1 mtDNA). Our phylogenetic analysis revealed the affinity of T. lindbergi to its congener T. laticaudi Parukhin, 1969, a digenean parasite commonly found in hydrophiine snakes inhabiting the Pacific Ocean. The interspecific divergence between T. lindbergi and T. laticaudi measures 3.80% for 28S, 7.49–7.64% for ITS2, and 16.29–16.70% for cox1. Our findings expand the documented geographic range of T. lindbergi into the southwestern Atlantic Ocean, report a novel host record, and increase the number of hemiurids known from Brazil to 30 species. Additionally, this study represents the initial documentation of a marine digenean fish within the North Brazil Shelf. Full article