Addressing taxonomic shortfalls in Neotropical gastrotrichs: a new genus and species of freshwater Gastrotricha (Chaetonotida: Paucitubulatina) from Brazil Axell K. Minowa, Alexander Kieneke, Maria Balsamo, Loretta Guidi, André R. S. Garraffoni Invertebrate Systematics, 2025 Freshwater meiofauna in the Neotropics remain vastly understudied, and many species are yet to be discovered due to sampling biases and methodological constraints. In this study, we describe Carianotus dives gen. nov., sp. nov., a new genus and species within Chaetonotidae (Chaetonotida: Paucitubulatina) from Brazil. This species, found in several regions spanning over 3000-km linear distance, features a unique set of morphological features, importantly a distinctive crest of five lanceolate-leaf-shaped spines deriving from small basal scales on the anterior dorsal head. The integrative description is based on light and scanning electron microscopy and molecular phylogenetic analyses of concatenated 18S and 28S rDNA sequences. Our analyses suggest the phylogenetic placement of Carianotus gen. nov. within a paraphyletic branch of Chaetonotus, with spined Chaetonotus lineages and spineless species of Lepidodermella. This research highlights the importance of integrative taxonomy in uncovering hidden biodiversity within the Neotropical region, and demonstrates the still underexplored status of the freshwater meiofauna of Brazil, with many species yet to be discovered. ZooBank: urn:lsid:zoobank.org:pub:D37B6DAB-6E0C-4D8B-B956-D29C066AA284
New branch on the tree of life of Gastrotricha: establishment of a new genus for limno-terrestrial species Axell Kou Minowa, Alexander Kieneke, Ariane Campos, Maria Balsamo, Michael Plewka, Loretta Guidi, Thiago Quintão Araújo, André RinaldoSenna Garraffoni Zoological Journal of the Linnean Society, 2025 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 mosses found in Atlantic rainforest within Serra do Japi biological reserve, and establishes its taxonomic status through morphological and molecular analyses. Morphological characterization was conducted using light microscopy, scanning electron microscopy, and confocal laser scanning microscopy, revealing that D. ibyrapora exhibits distinctive adaptations suited to limno-terrestrial environments, including unique cuticular adaptations and rearrangement of locomotory cilia. Molecular phylogenetics, using 18S and 28S ribosomal DNA sequences, supports the recognition of Dendroichthydium as a new genus, distinctly separated from known genera within Paucitubulatina. Furthermore, we propose reclassifying Chaetonotus (Chaetonotus) silvaticus to Dendroichthydium silvaticus comb. nov. based on shared morphological traits. The establishment of the genus Dendroichthydium reflects the ongoing need to re-evaluate gastrotrich diversity and taxonomy, highlighting the role of underexplored limno-terrestrial habitats in hosting unique life forms. This study underscores the importance of integrating morphology and genetics to improve our understanding of phylogenetics and the evolutionary dynamics of Gastrotricha.
Expanding the knowledge of Brazilian Gastrotrich biodiversity: Freshwater Paucitubulatina (Gastrotricha: Chaetonotida) from Northeastern Brazil Axell Kou Minowa, André Rinaldo Senna Garraffoni Zoologia, 2025 Knowledge of neotropical freshwater gastrotrichs, especially in Brazil, has gained momentum in the past decades, with new species being discovered yearly, accumulating in the last 30 years more than 10% of known species worldwide. Nevertheless, there is still much to accomplish in the field, with large geographical gaps to be filled, especially in continental countries such as Brazil. In the present study, we report the partial results of an expedition that, for the first time, sampled the inland waters of Alagoas, Bahía, and Pernambuco states, Northeast Region, Brazil, and found ten species belonging to five genera of Chaetonotidae. We report the first occurrence in Brazil of Chaetonotus majestuosus Grosso & Drahg, 1984, originally described from Argentina, and the second record in Brazil of Chaetonotus dadayi Schwank, 1990, originally found in Paraguay, and the first occurrence beyond ‘terra typica’ of Heterolepidodermella jureiense Kisielewski, 1991, originally discovered in Southeastern Brazil. Furthermore, we report members of species in conformity to species originally described in European countries Chaetonotus cf. persetosus Zelinka, 1889, and Chaetonotus cf. oculifer Kisielewski, 1981, although further investigations are needed to confirm the occurrence of such widespread lineages. Finally, we list three putative undescribed species related to Lepidochaetus aff. zelinkai (Grünspan, 1908), Chaetonotus aff. hoanicus Schwank, 1990 and Chaetonotus aff. acanthocephalus Valkanov, 1937. This new survey increases the list of northeast Brazilian freshwater gastrotrichs to 13 species.
Bryofaunal gastrotrichs from the Cerrado: First report of Dendroichthydium cf. ibyrapora from a Neotropical Savanna Axell K. Minowa, Vitor R. P. Ferreira, André R. S. Garraffoni Biota Neotropica, 2025 We present here a new record of Dendroichthydium cf. ibyrapora from epiphytic moss in Brazilian Cerrado within the Reserva do Roncador IBGE Ecological Reserve. This new finding provides further morphological data under light and electron scanning microscopy, and genetic data from 18S and 28S ribosomal DNA. The Cerrado animals fit neatly to the diagnostic morphological characteristics of the original description from Brazil’s Atlantic Rainforest, but they are smaller and feature genetic distance across both biomes.
Expanding the taxonomic catalog of Brazilian meiofauna: diversity and distribution of the neglected phyla Tardigrada, Gastrotricha, and Kinorhyncha André R.S. Garraffoni, Ariane Campos, Axell K. Minowa, Érika Santos, Maurício Moura, Rodolfo C. de Barros, Thiago Q. Araújo Zoologia, 2024 Meiofauna is a guild of microscopic organisms (delimited by the mesh width of two sieves, upper 500 μm and lower 44 μm) that inhabit the sediment grains and periphyton of aquatic environments (both freshwater and marine). Despite the fact that this definition is based on size, all the environments inhabited by these microorganisms present similar ecological challenges, which suggests that the meiofauna is a biologically and ecologically independent entity. Currently, meiofaunal organisms are represented in 23 of the 34 known metazoan phyla, including Tardigrada, Gastrotricha, and Kinorhyncha. The goal of this study was to compile information on the diversity and distribution of these phyla in Brazil. Based on the taxonomic contributions published until July 2023, a total of 97 Tardigrada species, 88 Gastrotricha species, and five Kinorhyncha species have been recorded. They are distributed throughout five biomes, eight hydrographic regions, 10 terrestrial biogeographic provinces, three marine biogeographical provinces, and 15 political states in Brazil. The species accumulation curve suggests that there are still many Tardigrada and Gastrotricha species to be discovered with increasing sampling effort, as the rate of discovery of new species is linearly increasing. Unfortunately, knowledge of the biodiversity of these meiofaunal groups is still limited due to sparse information on identity and distribution. We recommend future studies dealing with meiofauna taxa to prioritize redescribing endemic species based on integrative taxonomy and increase the number of the type series deposited in Zoological Museums (e.g., specimen photos). Furthermore, the training of researchers specialized in these taxa is a priority, as some of these phyla do not have any Brazilian specialists.
Freshwater and limno-terrestrial meiofauna of the Massane Forest Reserve in the Eastern French Pyrenees Nabil Majdi, Thiago Quintao Araujo, Nicolas Bekkouche, Diego Fontaneto, Joseph Garrigue, Laurent Larrieu, Lyudmila Kamburska, Alexander Kieneke, Axell Kou Minowa, Christopher Laumer, Raffaella Sabatino, Diane Sorel, Daniel Stec, Walter Traunspurger Biogeographia, 2024 We report the results of a faunistic survey focused on freshwater and limno-terrestrial meiofauna to improve biodiversity knowledge in a protected area in the Eastern part of the French Pyrénées: the Massane Forest Reserve (336 Ha). The survey provided 1187 occurrence records from 315 taxa (most resoved at species-level), uploaded as a shared online dataset. The highest number of occurrences and distinguishable morpho-taxon belong to the group Nematoda (775 occurrences, 172 taxa), followed by Rotifera (219 occurrences, 67 taxa), Platyhelminthes (85 occurrences, 32 taxa), Tardigrada (69 occurrences, 25 taxa), and Gastrotricha (39 occurrences, 19 taxa). A diversity of meiofaunal organisms was found, in large numbers, in all the samples screened: from stream biofilms and sediments, to forest floor soils, mosses, and litter, to a broad range of tree-related micro-habitats associated with beech-like epixylic mosses and lichens, tree cavities, woodpecker breeding holes, bark pockets and fruiting bodies of saproxylic fungi. This survey makes the Massane forest one of the few protected areas of the world with a taxa-inclusive meiofauna dataset, which could serve as a standard inventory to further consider micro-invertebrates in forest conservation.
