Taxonomy, Volume 5, Issue 2 (June 2025) – 18 articles

Ostariophysi is the second largest superorder of fishes, formed almost exclusively by freshwater species, with 102 families, 1372 genera, and 11,883 species, thus containing approximately 30% of the known fish species in the world and almost 70% of the freshwater species. Despite the great richness of species and, therefore, its great scientific and economic importance, there are still many problems related to the relationships among the internal groups of the superorder (and consequently in its classification), as well as doubts about its diversification processes and historical distribution. The group has been studied for centuries using morphological approaches that permitted the solution or proposal of several hypotheses about the origin, constitution, and distribution of the species of the group, but in the last three decades, new approaches using molecular data, including phylogenomics, have allowed the testing of hypotheses made with morphological data and, more importantly, the proposition of new hypotheses. The present study aims to review the current state of knowledge about the biodiversity, systematics, and taxonomy of the various groups of the superorder Ostariophysi, highlighting the advances achieved in recent years and discussing the problems still existing in the group. Full article

Taxonomy, primarily focused on systematically exploring, documenting, and characterizing global or regional biodiversity, represents a fundamental scientific discipline for biodiversity conservation and sustainability. However, it has encountered significant developmental constraints and academic marginalization in recent decades, resulting in a notable decline in proficient taxonomists as well as substantial gaps in taxonomic knowledge. In order to call for widespread attention and recognition of the increasing demands to revitalize and advance taxonomy, this article presents a comprehensive review that emphasizes the detrimental impacts of taxonomic knowledge gaps on the conservation and sustainable use of Paris (Melanthiaceae), a monocotyledonous genus hosting remarkable pharmaceutical significance and scientific importance. Overall, the conservation of threatened Paris species as well as the standardization of the cultivation of medicinal Paris species encounter numerous obstacles due to the scarcity of taxonomic expertise and presence of taxonomic knowledge gaps. These findings provide robust empirical evidence highlighting the crucial importance of taxonomy in biodiversity conservation and sustainability, thereby justifying the appeal to resurgence and advancement within this scientific discipline. Full article

With over 40 species, Eupeodes Osten Sacken, 1877, is a common aphidophagous hoverfly genus (Diptera: Syrphidae: Syrphinae) with a worldwide distribution. The immature stages of Eupeodes are well known, since 23 species have been reared, but only 8 species have been described. All known immature stages of Eupeodes species have predatory feeding habits, mainly on aphids and other soft-bodied Hemiptera, for which some of its species are commonly used as agents of biological control programs. In this work, the puparium of Eupeodes bucculatus (Rondani, 1857) is detailed and re-described, and the complete morphology of all immature stages of the life cycle of Eupeodes corollae (Fabricius, 1794) is documented by using stereomicroscope and scanning electron microscope techniques. An update to the taxonomic key for the known larvae/puparium of Eupeodes species is also provided. Full article

Three new species of Trichorhina are described from iron ore caves in the Serra dos Carajás Mountain Range, located in the Amazon Forest, Brazil. Trichorhina tucupi n. sp. occurs in Serra Leste, Serra da Bocaina and Serra do Tarzan Mountain Ranges. Trichorhina tacaca n. sp. occurs in caves in the Serra Norte Mountain Range. Trichorhina piloi n. sp. occurs in the Serra Sul and Serra Norte Mountain Ranges. Statistical methods were applied to investigate the putative morphological patterns of these species and to investigate their potential use in distinguishing Trichorhina species from epigean and hypogean habitats. Full article

Impatiens reidii Hook.f., a presumed extinct and Kumaon endemic species only known from its type collection in 1886, is rediscovered from near type locality after a gap of 138 years. The identity of the historically ambiguous name Impatiens tingens Edgew. is reinvestigated based on studies of literature, type specimens, and recollection of live material from the type locality that confirmed the name I. tingens is conspecific with I. scullyi Hook.f. and thus latter name is synonymised. Impatiens inayatii Hook.f., another little-known species described by Hooker as endemic to Kali valley, Kumaon currently treated as a synonym of Impatiens bicornuta Wall., is recollected from near the type locality after 124 years. Our recollection confirms its identity as a totally distinct species from section Urticifoliae S.Akiyama and H.Ohba, thus reinstating name I. inayatii. Augmented description for all three species is provided with information on their botanical history, species etymology, key identification characteristics, distribution, phenology, ecology, and first photographic documentation of I. reidii and I. inayatii. Also, lectotypes are designated for the names I. reidii, I. tingens, I. laxiflora var. stracheyi Hook.f. and I. micranthemum Edgew. Full article

Two new subterranean species of the genus Spelaeogammarus da Silva Brum, 1975 in Serra do Ramalho municipality, Bahia state, and Montes Claros municipality, Minas Gerais state, both in Brazil, are described herein. With these additions, the genus now comprises ten known species. This study includes a comparative table detailing the diagnostic characteristics of all Spelaeogammarus species and an updated genus diagnosis. Additionally, it provides insights into the species’ habitats and the threats they face. Some of the type localities mentioned in this study are not within protected areas, making these species particularly vulnerable to environmental risks. Threats primarily arise from surrounding land use, which can impact the water table and disrupt food resource availability. The discovery of these new troglobitic species underscores the urgent need for their inclusion in future threatened species assessments and highlights the importance of conservation measures to protect both the species and their cave habitats, along with the surrounding landscape. Finally, the discovery of these new species highlights the remarkable diversity of Spelaeogammarus in subterranean environments, emphasizing the need for further research and conservation efforts. Full article

New surveys on the Brazilian tropical coast revealed new occurrences of five species in Styelidae (Stolonia sabulosa, Amphicarpa paucigonas, Polyandrocarpa anguinea Polycarpa insulsa, Styela plicata) and one in Molgulidae (Molgula davidi). The species here described represent either the expansion of their geographic distribution in the country or new records for the country. Some of these species have disjunct or wide geographical distributions, and the possibility of their introduction as exotic fauna is discussed. We also present the first field pictures of Stolonia sabulosa and Amphicarpa paucigonas and a detailed description and figures for all species. Full article

We describe three new species: Canthon mezcalis Moctezuma, Sánchez-Huerta, and Halffter sp. nov. from the Valles Centrales region in Oaxaca, Mexico; Canthon hondurensis Moctezuma and Sánchez-Huerta sp. nov. from Honduras; and Canthon woodruffi Moctezuma and Sánchez-Huerta sp. nov. from Guanacaste, Costa Rica. Through the examination of external and genital morphology, Bayesian inference, and genetic distances based on the Kimura two-parameter model of nucleotide substitution, we confidently determined that the C. indigaceus species group is a monophyletic unit, which is integrated by a set of cryptic species. Full article

Athysanini is one of the largest tribes within Deltocephalinae, which is a vast cosmopolitan subfamily of leafhoppers (Hemiptera: Cicadellidae) with many genera known to occur in the Neotropical realm. Peruvian forests house up to 16 genera of Athysanini and, so far, are strongly restricted to this region. In this contribution, a new species of the leafhopper genus Andanus Linnavuori, 1959, Andanus acanthophallussp. nov., is described based on pinned museum specimens. Illustrations and a diagnosis for all species to segregate them in the genus are provided. A dichotomous key to all known species and distributional notes are also given. The new species can be easily separated from others by (1) overall color light orange to stramineous, (2) the pronotum lacking marks or transverse medial bands, (3) a row of very long fine setae on the outer lateral margin of the subgenital plate, (4) apophysis of style straight without lateral projection but minute tooth on inner side, and (5) an aedeagal apex bifid with a pair of processes directed anterad and posterad. The valid status and current position of Andanus based on similarities to other Neotropical genera is discussed. Full article

Mastogloia is a large, morphologically diverse genus of primarily benthic marine species defined by the presence of partecta (chambers) on the valvocopula (girdle band next to the valve). Several genera have been found with valves that resemble Mastogloia but lack the ring of partecta; the most diverse group is in freshwaters, especially Aneumastus, but there are two marine genera, both monotypic. A third such species has been found in Cuba and is described here as Paramastogloia cubana gen. nov., sp. nov. Paramastogloia cubana, Mastoneis biformis, and Mastogloiopsis biseriata each resemble the valve structure of some species of Mastogloia but do not resemble one another. Paramastogloia is indistinguishable in light microscopy (LM) from naviculoid diatoms and had been identified as Navicula cf. sovereigniae. The resemblance of P. cubana to Mastogloia is in the areolae, particularly to those of M. umbra, M. dicephala, and M. mammosa, three species not likely to be in one monophyletic group. Mastoneis has been observed in LM from widespread warm-water localities and resembles some Mastogloia in having costae extending partway across the virgae (interstriae); new ultrastructural details are presented showing the girdle bands and absence of partecta, and a clearer genus diagnosis is proposed. The third genus, Mastogloiopsis, was established with ultrastructure and resembles species of Mastogloia sec. Marginulatae. The range of areolar characters that might be admissible to Paramastogloia is unknown, so the generic diagnosis has been left imprecise to allow for the possibility of other species. The relationships among these genera await genetic studies, which are still scarce in Mastogloiaceae. Full article

The taxonomic positions of species in the genus Setina are poorly known and not well established, with ongoing uncertainties in their classification. In this work, the distribution of Setina irrorella pseudoirrorella Freina and Witt, 1985, and Setina cantabrica Freina and Witt, 1985, in Spain and Portugal is updated, expanding their distribution area based on revised bibliographic data and information provided by researchers and public or private collections. The taxonomic status of the binomial flavicans–irrorella and cantabrica–roscida are discussed, and their specific validity is analysed, comparing the differences observed between these taxa, which are studied on the basis of external morphological characteristics, genitalia, and molecular genetics. An updated distribution map is presented. The authors conclude that S. cantabrica and S. i. pseudoirrorella are the only two species of the genus Setina present in the Iberian Peninsula. Full article

Cnidarian jellyfish (Medusozoa) comprise approximately 3800 known species which play important roles for marine ecosystem. This study aimed to understand the diversity of cnidarian jellyfish and symbiosis among marine organisms. The taxonomy of the family Zancleidae (Hydrozoa, Anthoathecata) has been problematic because of the limited differences in morphological characteristics between species. This family comprises approximately 40 species belonging to four genera: Apatizanclea, Halocoryne, Zanclea, and Zanclella. In this study, we describe a new species of hydromedusa belonging to the family Zancleidae found in Japanese waters. Zanclea innocens sp. nov. can be distinguished from other Zanclea species by the presence of nematocyst clusters on the exumbrella, slightly thickened apical projection, four narrow exumbrellar nematocyst pouches on ridges often reaching the umbrella apex, four marginal bulbs, and two tentacles. Additionally, Zanclea medusopolypata was recorded for the first time in Japanese waters. This paper provides taxonomic keys for the identification of species in the genus Zanclea. Full article

Four new dung beetle species of the genus Onthophagus Latreille from Côte d’Ivoire, Burkina Faso, Bénin, and Cameroon are described, and a fragment of their COI gene is sequenced. The coprophagous Onthophagus (Trichonthophagus) sylviae sp. nov. from Côte d’Ivoire and Burkina Faso is most similar to Onthophagus pallidus d’Orbigny from Cameroon, but it is more elongated, more silky than shiny, and has no dark spot on the third elytral interstria. Onthophagus odikpatra sp. nov. (18th group of d’Orbigny) from Côte d’Ivoire, Burkina Faso, and Cameroon feeds on carrion, including dead millipedes and fish, and dung. It is most similar to Onthophagus baloghi Balthasar from Central Africa but has simple punctures on the sides of the pronotum. Onthophagus chinonophilus sp. nov. from Côte d’Ivoire and Burkina Faso, which feeds on freshly dead millipedes and is attracted by their quinonous defensive secretions; it also belongs to the 18th group in d’Orbigny’s classification. Small and medium individuals resemble small Onthophagus latigibber d’Orbigny but differ in shape and sculpture of the pronotum. Small individuals are also similar to Onthophagus tschadensis Balthasar (19th group) but differ in the shape of the aedeagus. The generalist feeder Onthophagus (Tiaronthophagus) necneavius sp. nov. (24th group) from Côte d’Ivoire, Burkina Faso, and Bénin is most similar to Onthophagus naevius from Zambia, DR Congo, and Tanzania, but it is smaller, shiny all over; the sides of pronotum behind anterior angles are almost straight, not distinctly emarginate, and the frons is densely covered with fine punctures. COI barcode sequences were provided for all four new species, but the poor sampling of Onthophagus in GenBank prevents meaningful analysis of species relationships on the basis of COI barcodes at this point. Full article

In this study, we provide a comprehensive description of a newly identified eutardigrade species, Mesobiotus longiconicus sp. nov., based on an integrative approach combining morphological and genetic data. The species was discovered at Lajuma Research Centre, Republic of South Africa, and is classified within the harmsworthi group. It can be differentiated from its closest relatives—Meb. barabanovi, Meb. ethiopicus, Meb. harmsworthi, Meb. reinhardti, and Meb. skorackii—by distinct morphological and morphometric characteristics of the bucco-pharyngeal apparatus, claws, and eggs. These morphological differences are further validated by genetic analyses using four molecular markers: 28S rRNA, 18S rRNA, COI, and ITS2. Additionally, two other tardigrade species were identified in the same locality, including Minibiotus pentannulatus, which is now recorded for the second time outside its type locality. With this discovery, the total number of tardigrade taxa reported from South Africa reaches 101, including Meb. longiconicus sp. nov. Full article

The Neotropical genus Nudopeza (Micropezidae, Taeniapterinae) is described for a group of 41 species, including Nudopeza tapanti sp. nov. (type species) and Nudopeza pronigra (Hennig) n. comb. for Grallipeza pronigra Hennig 1934, Nudopeza arcuata (Hennig) n. comb. for Grallipeza arcuata Hennig 1934, and the following 38 additional new species: N. cegex sp. nov, N. cura sp. nov, N. duplitheca sp. nov, N. gilli sp. nov., N. glypha sp. nov., N. gracei sp. nov., N. hansoni sp. nov., N. horologia sp. nov., N. laselva sp. nov., N. mephitis sp. nov., N. mexicana sp. nov., N. micromephitis sp. nov., N. nigrivertex sp. nov., N. nigriscutellum sp. nov., N. nudarcuata sp. nov., N. penai sp. nov., N. palenque sp. nov., N. paramephitis sp. nov., N. peruviensis sp. nov., N. quadrivitta sp. nov., N. ruficincta sp. nov., N. rutilans sp. nov, N. sirena sp. nov., N. sumaco sp. nov., N. trinidadensis sp. nov., N. uniseta sp. nov., N. variterga sp. nov., N. venezuelensis sp. nov., N. verpa sp. nov., N. versivitta sp. nov., N. viriola sp. nov., N. viva sp. nov., N. yungasensis sp. nov., N. zarza sp. nov., N. zostera sp. nov., N. zumera sp. nov., N. zygoma sp. nov., and N. zytha sp. nov. Full article

We describe a new species of snake of the genus Tachymenoides using molecular and morphological evidence. The description is based on 21 specimens (4 females, 17 males) obtained in the regions of Pasco, Junín, and Puno between 2190 and 3050 m elevation. A maximum likelihood phylogenetic tree based on two mitochondrial (12S and cyt-b) genes and one nuclear (c-mos) gene shows that the new species is the sister taxon of T. affinis and distinct from Galvarinus tarmensis, which we transfer back to Tachymenis. The new species has smooth dorsal scales without apical pits usually in 19/17/15 series, 1 preocular, 2 postoculars, 1 loreal undivided nasal scale, 8 supralabials (4th and 5th in contact with the eye), 9 infralabials, 1–2+2–3 temporals, 139–157 ventrals, 52–67 subcaudals, and a divided cloacal scale. The longest specimen, a male, had a total length of 559 mm. Two females contained six and five eggs with small embryos. In life, the dorsum and flanks are olive brown to pale grayish brown with scattered black and cream flecks and no longitudinal stripes. Ventral coloration is highly variable, nearly uniformly black, mottled gray and dark-gray, mottled pale gray and tan, or pale grayish tan. Usually, three irregularly shaped, narrow, longitudinal ventral stripes are present. The iris is brown with a distinct yellowish-tan ringlet. Full article

In this study on diatoms, which are unicellular microalgae with a siliceous cell wall, images obtained by electron microscopy were used to compare three taxa from East Asia that were referred as Cyclotella hubeiana, Discostella guiyangensis and “Cyclotella fottii” in the original studies. Morphometrical and morphological analyses indicate that these three taxa are conspecific. The distinctive morphological features of this species are the following: one rimoportula located on the valve mantle within the ring of marginal fultoportulae, marginal fultoportulae situated on costae with internally two satellite pores positioned circumferentially (laterally) and externally long tubular opening, biseriate striae and branching costae. A comparison of these morphological features with those of Discostella and Cyclotella species and a re-assessment of the existing molecular data suggest that this species could be separated from both these genera. On this basis, we describe the new genus Discocyclus gen. nov. with Discocyclus hubeianus comb. nov. as the type species. Full article

The freshwater cyanobacterium Raphidiopsis raciborskii is an invasive species that was originally described as tropical and is now widely distributed in temperate regions. The current taxonomic position was established based on a multilevel approach with the morphological description of natural populations as well as their ultrastructural, physiological and molecular characterization. The practical problem in identifying this species is that the morphology of the trichome in the natural environment can vary considerably during population growth. The aim of this study was to investigate the morphological variability of R. raciborskii during its blooming in a temperate floodplain lake on the Middle Danube (Europe). In both cases, only straight trichomes were found. Young trichomes with one or two acuminate ends and without heterocytes, referred to as primary filaments, can be exclusively monodominant at the beginning of bloom formation and remain dominant throughout the year, leading to taxonomic confusion. In mature populations, the different morphological forms of secondary filaments may differ in the size of the filaments and in the number and size of akinetes and heterocytes formed in the trichomes. The correct taxonomic identification and early detection of R. raciborskii in natural freshwaters is extremely important for the successful control of the spread of this potentially toxic species. Full article