Restricted Geographic Distribution Research Articles

How Do Species Traits and Biogeographical Factors Determine the Fate of Amphibians After Long‐Term Fragmentation?

ABSTRACTAimIdentifying key factors that render certain species more vulnerable to fragmentation is vital for elucidating processes underlying extinction and targeting conservation priorities. However, few studies have explored the delayed ecological responses of species following isolation. To bridge the gap, we conducted comprehensive analyses of correlates of extinction vulnerability and biogeographical variation in amphibians over long‐term fragmentation.LocationZhoushan Archipelago, China.MethodsWe sampled the occupancy of amphibians on 37 land‐bridge islands. We calculated three metrics of extinction vulnerability (population extinction rate, island occupancy frequency and species nestedness ranking) for each species and correlated these variables with eight species' traits. We further explored biogeographical variations in amphibians by relating five biogeographical variables to species' probability of occurrence and calculated the threshold for the persistence of each species on islands.ResultsSpecies with low natural abundance, larger egg sizes, smaller clutch sizes or restricted geographical distributions were more likely to experience higher population extinction rates and species nestedness rankings, while lower island occupancy frequencies across islands. Although most species were found on larger islands, we observed significant increases in the occurrence probabilities with island area for five species. The estimated areas with a 50% chance of occurrence ranged from 0.39 to 199.5 km2. Interestingly, the likelihood of occurrence of Hyla chinensis (treefrog) was negatively related to distance to the mainland after controlling for the effect of area.Main ConclusionsOur study highlights the variation in the fragmentation sensitivity of amphibians. Species distribution was primarily regulated by area‐related extinction, particularly for those with ‘slow’ life history strategies or restricted ranges. Overall, management efforts should focus on species with extinction‐prone traits and landscape features that threaten the persistence of populations. Future studies should consider the sequential separation of island populations and the interaction of traits to reveal the fate of species to fragmentation.

Metabolic capabilities are highly conserved among human nasal-associated Corynebacterium species in pangenomic analyses.

Pangenomic analysis with estimation of functional capabilities facilitates our understanding of the full biologic diversity of bacterial species. We performed systematic genomic, phylogenomic, and pangenomic analyses with qualitative estimation of the metabolic capabilities of four common human nasal Corynebacterium species, along with focused experimental validations, generating a foundational resource. The prevalence of each species in human nasal microbiota is consistent with the common coexistence of at least two species. We identified a notably high level of metabolic conservation within and among species indicating limited options for species to occupy distinct metabolic niches, highlighting the importance of investigating interactions among nasal Corynebacterium species. Comparing strains from two continents, C. pseudodiphtheriticum had restricted geographic strain distribution characterized by an evolutionarily recent loss of assimilatory sulfate reduction in U.S. strains. Our findings contribute to understanding the functions of Corynebacterium within human nasal microbiota and to evaluating their potential for future use as biotherapeutics.

Phenology and social status of the endemic Sable Island Sweat Bee, Lasioglossum sablense

Lasioglossum (Dialictus) sablense Gibbs, 2010 (Hymenoptera: Halictidae) is endemic to Sable Island, an isolated sandbar located about 160 km east of Nova Scotia, Canada. Lasioglossum sablense is currently listed as Threatened due to its restricted geographic distribution, and promoting its conservation requires detailed information about nesting phenology, behaviour, and other life history details. We combined measurements of body size, wear, and ovarian status from adult females collected from flowers in 2016 and 2017 with measurements and behavioural observations of foragers collected at the Sable Island Station in 2019 and 2022, to compile a preliminary description of flight phenology and social behaviour. Like many members of its genus, L. sablense exhibited a diphasic life history. Phase 1 began when large, fertilized adult females emerged from hibernation, began nest and brood cell construction, and foraged to provision Brood 1, which comprised both daughters and sons. Most nests initiated during Phase 1 reactivated during Phase 2, with adult Brood 1 daughters foraging to provision Brood 2. Observations of bees at nest entrances demonstrated that some reactivated nests contained multiple adult females. Phase 1 foragers were larger, less worn, and had marginally higher levels of ovarian development than Phase 2 foragers. Five large females collected during Phase 2 had high levels of wear, suggesting they were long-lived Phase 1 foundresses that resumed foraging during Phase 2. Taken together, these observations suggest a mix of univoltine (single generation) and bivoltine (two generation) life histories, as well as a mix of solitary and social behaviour in L. sablense.

Lithium ore tailings harm the vegetative development, photosynthetic activity, and nutrition of tree species.

Lithium (Li) exploitation promotes socioeconomic advances but may result in harmful environmental impacts. Thus, species selection for recovering environments degraded by Li mining is essential. We investigated the tolerance and early growth of four tree species to Li ore tailings (LOT), Enterolobium contortisiliquum and Handroanthus impetiginosus with wide geographic distribution and Hymenaea courbaril and H. stigonocarpa with restricted geographic distribution. The plants grew in LOT and soil for 255days to evaluate photosynthesis, growth, and mineral nutrition. LOT negatively affected species growth, reducing the length of stems, roots, and biomass through structural and nutritional impoverishment. LOT favored the accumulation of Mg and decreased the absorption of K. The species presented a reduction in potential quantum efficiency and the chlorophyll index (b and total). E. contortisiliquum was the least tolerant species to LOT, and H. courbaril and H. stigonocarpa maintained their mass production in LOT, indicating greater tolerance to tailings. Furthermore, H. courbaril presented a translocation factor > 1 for Li and Mn, indicating the potential for phytoextraction of these metals. Our results offer first-time insights into the impacts of LOT on the early development of tree species with different geographic distribution ranges. This study may help in the tree species selection with a phytoremediation role, aiming at the recovery of areas affected by Li's mining activity.

STERILIZATION AND STUDY OF GERMINATION OF ASTRAGALUS KNORRINGIANUS SEEDS IN VITRO CONDITIONS

The global decline of plant species exerts a significant detrimental impact on the stability of natural ecosystems. Endemic species with restricted geographical distributions are at risk of extinction in their natural habitats. Consequently, the investigation of rare plant species, the analysis of their current status, and the development of conservation measures are of substantial scientific and practical significance. Astragalus knorringianus Boriss. represents one such critical plant species.

Metabolic capabilities are highly conserved among human nasal-associated Corynebacterium species in pangenomic analyses.

Corynebacterium species are globally ubiquitous in human nasal microbiota across the lifespan. Moreover, nasal microbiota profiles typified by higher relative abundances of Corynebacterium are often positively associated with health. Among the most common human nasal Corynebacterium species are C. propinquum, C. pseudodiphtheriticum, C. accolens, and C. tuberculostearicum. To gain insight into the functions of these four species, we identified genomic, phylogenomic, and pangenomic properties and estimated the metabolic capabilities of 87 distinct human nasal Corynebacterium strain genomes: 31 from Botswana and 56 from the USA. C. pseudodiphtheriticum had geographically distinct clades consistent with localized strain circulation, whereas some strains from the other species had wide geographic distribution spanning Africa and North America. All species had similar genomic and pangenomic structures. Gene clusters assigned to all COG metabolic categories were overrepresented in the persistent versus accessory genome of each species indicating limited strain-level variability in metabolic capacity. Based on prevalence data, at least two Corynebacterium species likely coexist in the nasal microbiota of 82% of adults. So, it was surprising that core metabolic capabilities were highly conserved among the four species indicating limited species-level metabolic variation. Strikingly, strains in the USA clade of C. pseudodiphtheriticum lacked genes for assimilatory sulfate reduction present in most of the strains in the Botswana clade and in the other studied species, indicating a recent, geographically related loss of assimilatory sulfate reduction. Overall, the minimal species and strain variability in metabolic capacity implies coexisting strains might have limited ability to occupy distinct metabolic niches.

Differential rates of Mycobacterium tuberculosis transmission associate with host-pathogen sympatry.

Several human-adapted Mycobacterium tuberculosis complex (Mtbc) lineages exhibit a restricted geographical distribution globally. These lineages are hypothesized to transmit more effectively among sympatric hosts, that is, those that share the same geographical area, though this is yet to be confirmed while controlling for exposure, social networks and disease risk after exposure. Using pathogen genomic and contact tracing data from 2,279 tuberculosis cases linked to 12,749 contacts from three low-incidence cities, we show that geographically restricted Mtbc lineages were less transmissible than lineages that have a widespread global distribution. Allopatric host-pathogen exposure, in which the restricted pathogen and host are from non-overlapping areas, had a 38% decrease in the odds of infection among contacts compared with sympatric exposures. We measure tenfold lower uptake of geographically restricted lineage 6 strains compared with widespread lineage 4 strains in allopatric macrophage infections. We conclude that Mtbc strain-human long-term coexistence has resulted in differential transmissibility of Mtbc lineages and that this differs by human population.

The first record of the genus orbirhynchia (Brachiopoda: tetrarhynchidae) from the upper Campanian of Algeria

ABSTRACT The species Orbirhynchia mantilliana is newly documented in Algeria, identified within the Upper Campanian marly limestone of the Akhdar Member in the Abiod Formation at Djabel Gueroun, Batna Province, Aurès Basin. It is associated with Upper Campanian faunal markers such as the ammonite species Nostoceras (Bostrychoceras) polyplocum, found within the planktic foraminifera Globotruncana calcarata Zone. The O. mantilliana displays a restricted geographic distribution and biogeographic range, confined to Algeria, the United Kingdom, and Germany.

Guadua guzmanii (Poaceae: Bambusoideae: Bambuseae: Guaduinae): A new woody bamboo species endemic to Jalisco, Mexico

Guadua comprises 35 described species, seven of which are distributed in Mexico. Since 1976, a specimen corresponding to the genus Guadua was collected, which could not be correctly assigned to any described taxon. In the present study, a new species of Guadua endemic to the state of Jalisco is described based on vegetative characters. Herbarium specimens were reviewed, field collections made, and specialist literature consulted. A comparison with similar specimens was conducted. The degree of threat was determined following the criteria of the International Union for Conservation of Nature (IUCN). Guadua guzmanii, endemic to the El Tamarindo peninsula, municipality of La Huerta, Jalisco, is described. We include a morphological key for the species of the genus Guadua in Mexico, an illustration, photographs, and a distribution map. According to the IUCN criteria, the species is classified as Critically Endangered due to its restricted geographical distribution. With the description of Guadua guzmanii, the number of native Guadua species in Mexico increases to eight. Additionally, the number of woody bamboos in Mexico increases to 60, with 43 species endemic to Mexico and four endemic to Jalisco, included: Chusquea contrerasii, Chusquea guzmanii, Rhipidocladum singuliflorum, and Guadua guzmanii.

Harnessing the Cross-Neutralisation Potential of Existing Antivenoms for Mitigating the Outcomes of Snakebite in Sub-Saharan Africa.

Over 32,000 individuals succumb to snake envenoming in sub-Saharan Africa (sSA) annually. This results from several factors, including a lack of antivenom products capable of neutralising the venoms of diverse snake species in this region. Most manufacturers produce polyvalent antivenoms targeting 3 to 16 clinically important snake species in sSA. However, specific products are unavailable for many others, especially those with a restricted geographic distribution. While next-generation antivenoms, comprising a cocktail of broadly neutralising antibodies, may offer an effective solution to this problem, given the need for their clinical validation, recombinant antivenoms are far from being available to snakebite victims. One of the strategies that could immediately address this issue involves harnessing the cross-neutralisation potential of existing products. Therefore, we assessed the neutralisation potency of PANAF-Premium antivenom towards the venoms of 14 medically important snakes from 13 countries across sSA for which specific antivenom products are unavailable. Preclinical assays in a murine model of snake envenoming revealed that the venoms of most snake species under investigation were effectively neutralised by this antivenom. Thus, this finding highlights the potential use of PANAF-Premium antivenom in treating bites from diverse snakes across sSA and the utility of harnessing the cross-neutralisation potential of antivenoms.

Impact of Quaternary Amazonian river dynamics on the diversification of uakari monkeys (genus Cacajao)

AbstractAimThe central and western Amazonia underwent several landscape changes during the Quaternary. Whereas the Riverine Barrier Hypothesis is traditionally used to explain the influence of rivers on speciation, processes such as river rearrangements have been overlooked to explain the geographic distribution and evolutionary history of Amazonia biota. Here, we tested how river rearrangements influenced the evolutionary history of uakari monkeys, genus Cacajao, a primate genus primarily associated with seasonally flooded forests in central and western Amazonia.LocationCentral and Western Amazonia.TaxonThe genus Cacajao, including the black uakaris (C. melanocephalus, C. ayresi, C. hosomi); and the bald‐headed uakaris (C. calvus, C. amuna, C. rubicundus, C. ucayalii, C. novaesi).MethodsWe performed a continuous phylogeographic analysis using 77 cytochrome b sequences to identify the origin and dispersal of Cacajao lineages. We used genome‐wide SNP variation (ddRADseq) to investigate population structure, gene flow and demographic history in Cacajao populations and used digital elevation models to identify landscape and riverscape characteristics that may have influenced the geographic distribution of Cacajao.ResultsOur continuous phylogeographic reconstruction pointed out that the ancestral Cacajao lineage occupied the flooded forests of the Solimões River, in central Amazonia, at ~1.7 Mya and descendant lineages dispersed throughout central and western Amazonia more recently. We identified gene flow in both black and bald‐headed uakari populations, even across rivers considered barriers (e.g. the Negro River). Landscape analysis showed that river rearrangements influenced the geographic distribution and population structure in Cacajao. Historical demographic analyses suggest varied scenarios of population size changes among Cacajao monkeys consistent with periods of intense dynamism in flooded habitats and the formation of non‐flooded upland forests.Main ConclusionOur results support that the river rearrangements have shaped the geographic distribution and divergence of recently diverged Cacajao lineages. Landscape and riverscape changes, along with retractions of the flooded forests, isolated some Cacajao populations in floodplain areas. Our study also suggests that these events led to the recent changes in demographic histories in species with a restricted geographic distribution.

Rediscovery of the Neotropical orchid Porroglossum parsonsii and recommendations for its conservation

Abstract Understanding the distribution and habitat requirements of species is crucial for designing conservation actions, yet this information is not available for many plant species. We report the first confirmed wild populations of Porroglossum parsonsii, which, because of its horticultural value, is commercialized in national and international markets, from where it was first described to science. Our large-scale survey of 341 10 × 30 m plots spanning Andean forests, paramo habitats and pasturelands in Colombia suggests that P. parsonsii has a restricted geographical distribution in Andean forests with high forest cover (71.4–86.2%), where it occurs in low numbers (5–17 individuals per plot). Because of its market value (USD 18–20 per plant) there is a risk the species could be collected illegally, and therefore the habitat of the species in the Santuario de Fauna y Flora de Iguaque requires appropriate conservation.

Restricted geographical distribution of Cremnophila Nutans (Crassulaceae): implications to the conservation of a micro-endemic, habitat specialist and ornamental Mexican plant

Restricted geographical distribution of Cremnophila Nutans (Crassulaceae): implications to the conservation of a micro-endemic, habitat specialist and ornamental Mexican plant

Three new species in Russula subsection Xerampelinae supported by genealogical and phenotypic coherence

ABSTRACT Xerampelinae is a subsection composed of species of ectomycorrhizal fungi belonging to the hyperdiverse and cosmopolitan genus Russula (Russulales). Species of Xerampelinae are recognized by their fishy or shrimp odor, browning context, and a green reaction to iron sulfate. However, species delimitation has traditionally relied on morphology and analysis of limited molecular data. Prior taxonomic work in Xerampelinae has led to the description of as many as 59 taxa in Europe and 19 in North America. Here we provide the first multilocus phylogeny of European and North American members based on two nrDNA loci and two protein-coding genes. The resulting phylogeny supports the recognition of 17 species-rank Xerampelinae clades; however, higher species richness (~23) is suggested by a more inclusive nuclear rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS barcode) analysis. Phylogenetic and morphological analyses support three new species with restricted geographic distributions: R. lapponica, R. neopascua, and R. olympiana. We confirm that the European species R. subrubens is present in North America and the North American species R. serissima (previously known as R. favrei) is present in Europe. Most other Xerampelinae appear restricted to either North America or Eurasia, which indicates a high degree of regional endemism; this includes R. xerampelina, a name widely applied to North American taxa, but a species restricted to Eurasia.

The first USA continental record of coffee leaf rust (Hemileia vastatrix) on coffee (Coffea arabica) in southwest Florida, USA.

Coffee leaf rust (CLR), caused by Hemileia vastatrix Berk. & Broome (Zaghouaniaceae) is considered the most significant fungal disease of Coffea arabica L. (Rubiaceae), from which berries are harvested and processed to obtain coffee beverage (Talhinhas et al. 2017). In Florida, coffee plants are mainly used as ornamentals due to their fragrant flowers; however, there are ongoing field trials evaluating the adaptability of plants for coffee production to climate conditions in the state (Crane et al. 2005). In November 2021, young seedlings of C. arabica var. caturra from a residence in Naples (Collier County) in southwest Florida were discovered with signs of rust fungus. Minute, yellow, suprastomatal sori 53-81 µm in diam were formed on the abaxial leaf surface, forming blotches. Light-yellow urediniospores measured 29-31 × 20-29 µm, with a reniform or "hunchbacked" shape, had thick walls measuring 1.5-2.5 µm in height, and were dorsally echinulate, the individual spikes measuring 2.5-3.3 µm in height. Spikes were scattered over most of the dorsal surface and form a dense ridge separating the dorsal from the smooth ventral side. (e-Xtra Fig. 1). Symptoms and signs are consistent with published descriptions of CLR produced by H. vastatrix (Ritschel 2005). To confirm the identification, DNA sequencing of the large subunit (LSU) of the ribosomal repeat was done following the protocols of Aime (2006) (GenBank accession number OR296753-OR296754). The Florida specimen shares 100% sequence identity (887/728 bp) with other accessions of H. vastatrix in congruence with maximum likelihood phylogenetic analysis performed in RAxMLv8.0.0 (Stamatakis 2014) (e-Xtra Fig. 2). In addition to CLR, Hemileia coffeicola Maubl. & Roger, causal agent of powdery rust of coffee, produces similar leaf spots on coffee but has a restricted geographical distribution. This agent is found only above 500 m a.s.l. in central Africa (Silva et al. 2006) and produces larger urediniospores (34-40 × 20-28 µm) (Maublanc & Roger 1934) in sori are scattered in abaxial leaf surface giving a powdery appearance. Hemileia vastatrix has been reported from almost every major coffee growing country of the world as well as Hawaii and Puerto Rico (Keith et al. 2022, Ramirez-Camejo et al., 2022). This is the first report of CLR in the continental USA, however, CLR poses a limited threat to the USA agriculture in view of the fact coffee is not commercially grown within the continental USA. A voucher was made of dried symptomatic leaves and deposited at Plant Industry Gainesville Herbarium (PIHG 15712, 16332) and the Arthur Fungarium at Purdue University (PUR N23473). The remaining infested coffee seedlings were destroyed after phytopathological diagnosis, and the pathogen has been absent from all additional screenings since November 2021.

Environmental and geographic low suitability overlapping of geoduck clams in the Pacific Northeast predicted by Ecological Niche Modeling

The known distribution limits of geoduck clams (genus Panopea) remain geographically separated globally. However, in the northeast Pacific, P. generosa is distributed from Alaska to northern Mexico, but approaches, and likely overlaps, the distribution of P. globosa, which is mainly distributed in the Gulf of California. There is incipient evidence that both populations coexist in the central part of the Baja California Peninsula on the Pacific coast. However, knowledge of the biogeographic distribution and environmental conditions for both species is still developing. To address the hypothesis of coexistence in the same geographic space, we developed distribution area models using ecological niche modeling through the maximum entropy algorithm. The algorithm used presence-only records and environmental layers (predictive variables) such as mean surface temperature, mean salinity, mean depth, temperature range, and primary productivity. The results indicate that both species overlap in a narrow portion of the environmental space (Grinnellian ecological niche), which is reflected in a restricted geographic distribution with conditions of low abiotic suitability. Our results contribute to directing new research in the areas of ecology, biogeography, paleontology, and geoduck clam fisheries management.

Pleistocene climatic oscillations influenced the emergence of geographically widespread and restricted genetic lineages in an Andean grasshopper species group

Abstract The grasshopper Trimerotropis pallidipennis species complex is distributed across arid and semi-arid environments from North to South America, reaching high altitudes along the Andes Mountain range. Currently, there are four valid species of Trimerotropis in South America. However, some species were found to comprise several genetic lineages. Here, we describe the genetic structure, lineage diversification, and environmental requirements within the Trimerotropis species complex in South America based on sequences from the mitochondrial COI gene, 4048 single nucleotide polymorphisms, and ecological niche modelling. The analyses revealed the existence of at least five lineages: two with a restricted geographical distribution and three with a very wide one. The results provide evidence that glacial cycles promoted not only the presence of refuge areas but also the isolation of widely distributed lineages on the eastern and western sides of the southern Andes, potentially driving the emergence of the Trimerotropis sp. lineage, which can tolerate more temperate habitats. Our results provide evidence for the effects of Pleistocene climatic changes on the diversification history of a South American grasshopper species complex.

Molecular species delimitation of marine trematodes over wide geographical ranges: Schikhobalotrema spp. (Digenea: Haplosplanchnidae) in needlefishes (Belonidae) from the Pacific Ocean and Gulf of Mexico.

Geographical distribution plays a major role in our understanding of marine biodiversity. Some marine fish trematodes have been shown to have highly restricted geographical distributions, while some are known to occur over very wide ranges; however, very few of these wide distributions have been demonstrated genetically. Here, we analyse species of the genus Schikhobalotrema (Haplosplanchnidae) parasitizing beloniforms from the tropical west Pacific, the eastern Pacific and the Gulf of Mexico (GoM). We test the boundaries of these trematodes by integrating molecular and morphological data, host association, habitat of the hosts and geographical distribution, following a recently proposed and standardized delineation method for the recognition of marine trematode species. Based on the new collections, Schikhobalotrema huffmani is here synonymized with the type-species of the genus, Schikhobalotrema acutum; Sch. acutum is now considered to be widely distributed, from the GoM to the western Pacific. Additionally, we describe a new species, Schikhobalotrema minutum n. sp., from Strongylura notata and Strongylura marina (Belonidae) from La Carbonera coastal lagoon, northern Yucatán, GoM. We briefly discuss the role of host association and historical biogeography of the hosts as drivers of species diversification of Schikhobalotrema infecting beloniforms.

A new small carder bee species from the eastern Canary Islands (Hymenoptera, Megachilidae, Anthidiini)

Recent field surveys in the eastern Canary Islands (Spain), followed by contributions of new occurrence records through the citizen science platform iNaturalist.com and the social media photo repository Flickr.com have revealed the presence of an overlooked small carder bee species (genus Pseudoanthidium Friese (Megachilidae: Anthidiini)) on the islands of Lanzarote and Fuerteventura. Here, we combined morphology, DNA barcodes (mitochondrial cytochrome c oxidase subunit I, COI) and ecological data (distribution, altitudinal ranges and environmental niche classification) to describe this species as Pseudoanthidium (Pseudoanthidium) jacobiisp. nov. We provide an illustrated description along with diagnostic morphological characters to separate it from P. (P.) canariense (Mavromoustakis, 1954), the only other congeneric species known from the neighbouring islands of La Gomera, Tenerife and Gran Canaria and from which it is separated by a genetic distance of 2.7%. We also evaluated the extent of shared environmental niche space among the two Pseudoanthidium species, and our results show a significant difference in elevation range as well as a very small (less than 1%) overlap between the modelled climatic niche of P. jacobii and that of P. canariense. Given the extremely restricted geographic distribution and the fragile and isolated nature of the habitat and host plants of this new island endemic species, we assign it an IUCN conservation status of “EN” (endangered) and discuss avenues for future research on the ecology and conservation of wild bees in the Canary Islands and neighbouring regions.

Tardigrade Augean stables—a challenging phylogeny and taxonomy of the family Ramazzottiidae (Eutardigrada: Hypsibioidea)

Abstract Tardigrade taxonomy is most often hindered by prevalent outdated species descriptions, lack of integrative redescriptions, scarce genetic information, and fragmentary sampling. Here, we diagnose the problems obscuring phylogenetic inference and the taxonomy of the cosmopolitan family Ramazzottiidae. We carried out the most extensive phylogenetic analysis of this family to date, with a considerable influx of new genetic data from poorly sampled regions of the world. We found two new distinct evolutionary lineages defined by distinct morphological traits (dorsal cuticular sculpturing and/or body shape), characterized by restricted geographic distributions, and we delineated them as new species complexes: the Neotropical Ramazzottius baumanni complex and the Afro-Oriental Ramazzottius szeptyckii complex. Nevertheless, we could not confidently ascertain the taxonomic status of both complexes due to: (i) the current state of the ramazzottiid taxonomy, with outdated and/or imprecise species descriptions with heterogeneous terminology and, in many cases, without accounting for intraspecific variation; (ii) the missing genetic information for key taxa; and (iii) the possible lack of monophyly of Cryoconicus and Ramazzottius as suggested by our results. In addition to diagnosing the problems of ramazzottiid phylogeny and systematics, we also propose possible solutions that could accelerate the progress in our understanding of the evolution of this group.