Chapada Dos Veadeiros Research Articles

Distribution and historical aspects of Brazilian Stachytarpheta (Verbenaceae): Exploring a comprehensive dataset of taxonomically verified specimens

Stachytarpheta (Verbenaceae) encompasses approximately 120 species distributed throughout tropical and subtropical regions of the Americas, with Brazil boasting the highest species richness (90 spp.) and endemism (82 spp.). This study introduces an updated, taxonomically revised, and credible occurrence dataset focusing on Stachytarpheta species in Brazil, comprising 4,843 records. This dataset results from expert revision of herbarium collections and integration with global repositories alongside national repositories in Brazil. It facilitates a thorough exploration of the temporal, geographical, and taxonomic patterns of Stachytarpheta across diverse regions and landscapes in Brazil. Stachytarpheta species and their occurrence records are concentrated in the states of Minas Gerais, Bahia, and Goiás, particularly in the campo rupestre and savanna formations of the Espinhaço Range and Chapada dos Veadeiros. Analysis of potential biases within our dataset revealed a correlation between specimen occurrences and proximity to roads. Rarefaction curves indicate ongoing potential for species discovery within the Cerrado and Caatinga domains, with the Tocantins state emerging as a particularly promising area for novel findings; therefore, presenting opportunities for exploration. The majority of the specimens are housed in Brazilian herbaria, particularly at RB, HUEFS, and CESJ. Temporal analysis of occurrence records showed an upward trend during the 20th century and the first decade of the 21st century, which can be attributed to the efforts of generalist collectors working mostly in Eastern and Central Brazil. Most collection efforts were carried out through Brazilian and European initiatives, often supported by local funding, especially during the mid-20th century. However, funding for scientific initiatives in Brazil has waned since the mid-2010s, potentially affecting recent trends in species recording. Our dataset serves as a resource enabling subsequent analysis delving into the systematics, biogeography, and conservation of this remarkable genus from open vegetation formations in Brazil.

Unraveling the genetic diversity of Ceiba pubiflora (Malvaceae) in isolated limestone outcrops: Conservation strategies.

Seasonally Dry Tropical Forests (SDTFs) located on limestone outcrops are vulnerable to degradation caused by timber logging and limestone extraction for cement production. Some of these forests represent the last remnants of native vegetation cover, functioning as isolated islands. Ceiba pubiflora (Malvaceae) is a tree frequently found on limestone outcrops in the central region of Brazil. This study aimed to evaluate the genetic diversity and identify suitable populations for the establishment of Management Units (MUs) for conservation. Inter-simple sequence repeat markers were employed to assess the genetic diversity in ten populations sampled from the Caatinga, Cerrado, and Atlantic Forest biomes. The species exhibited substantial genetic diversity (HT = 0.345; PLP = 97.89%). Populations SAH, JAN, and MON demonstrated elevated rates of polymorphic loci (> 84.2%) along with notable genetic diversity (He > 0.325). Additionally, these populations were the primary contributors to gene flow. The analysis of molecular variance (AMOVA) indicated that most genetic variation occurs within populations (91.5%) than between them. In the Bayesian analysis, the ten populations were clustered into five groups, revealing the presence of at least three barriers to gene flow in the landscape: 1) the Central Plateau or Paranã River valley; 2) near the Espinhaço mountains or the São Francisco River valley; and 3) around the Mantiqueira mountain range, Chapada dos Veadeiros plateau, and disturbed areas. A positive and statistically significant correlation was observed between genetic (θB) and geographic distances (r = 0.425, p = 0.008). Based on these findings, we propose the establishment of Management Units in Minas Gerais state, encompassing the (1) southern region (MIN population), (2) central region (SAH population), and (3) north region (MON population), as well as in Goiás state, covering the (4) Central Plateau region. These units can significantly contribute to preserving the genetic diversity of these trees and protecting their habitat against ongoing threats.

Two new and endangered species of Paepalanthus sect. Diphyomene (Eriocaulaceae) from the Brazilian Cerrado

Two new species of Paepalanthus (Eriocaulaceae) from the Cerrado hotspot in central Brazil are described and illustrated. Paepalanthus avacanoeiro Trovó & R. Silva-Oliveira sp. nov. occurs in the Chapada dos Veadeiros region, growing on quartzite rocky soils. The species is similar to P. urbanianus, distinguished mainly by being a more robust species with pilose and patent leaves with blackish base and ciliated margin, by its reproductive axis covered by remotely disposed bracts with acuminate apex, and by its inflorescence with fewer scapes. It is currently known from two subpopulations occurring just outside of the local conservation units and is assessed as Critically Endangered (CR). Paepalanthus burle-marxii Trovó sp. nov. is distributed in the vicinities of Brasília, Pirenópolis, Luziânia, and Santo Antônio do Descoberto. It is known from many historical and recent collections inhabiting typical open grasslands, usually over argillaceous-rocky soils. It is distinguished from P. linearis, its most similar species, by its glabrous and wider leaves with membranaceous margin, its narrower capitula with few flowers and dark castaneous involucral bracts, and by the pilosity of the pistillate flower sepals. It is assessed as Vulnerable (VU). Line drawings, photos taken in the field, distribution maps, and comments are provided alongside its conservation status and IUCN red list categories.

MONITORAMENTO DE TRIHALOMETANOS (THMs) E DA QUALIDADE DA ÁGUA PARA ABASTECIMENTO PÚBLICO DA CIDADE DE CAVALCANTE, GOIÁS

MONITORING OF TRIHALOMETHANES (THMs) AND WATER QUALITY FOR PUBLIC SUPPLY IN THE CITY OF CAVALCANTE, GOIÁS. Trihalomethanes (THMs) are organohalogens compounds formed from the reaction between free residual chlorine and natural matter organic (humic substances) present in raw water from surface sources. This study aimed to evaluate the formation of THMs resulting from the application of chlorine for disinfection, in the water treating process for public supply in the city of Cavalcante, GO, located in the region of Chapada dos Veadeiros (Brazil). The results of physical-chemical analyses apparent color, turbidity, pH, free residual chlorine, consumed oxygen, hardness, total alkalinity and THMs demonstrated a positive and strong correlation between the formation of THMs and the hardness of treated water, as well as the chlorine consumed during disinfection process. It was observed an increase in apparent color, turbidity and consumed oxygen in the rainy season. These parameters indicate the presence of organic matter and that present a positive and moderate correlation with the formation of THMs.

Transição agroecológica em assentamento rural na Chapada dos Veadeiros

Abstract The sustainability of organic production and the agroecological transition of farmers in the Chapada dos Veadeiros region was evaluated using the Environmental Impact Assessment System of Agricultural Technological Innovations (AMBITEC-AGRO). The evaluation process consisted of three stages: 1st survey and data collection, 2nd application of questionnaires and 3rd individual interviews. Data were entered into electronic spreadsheets, generating quantitative results of the impacts of activities carried out on rural properties. The indicators of the data obtained are organized in weighting matrices and automatically transformed into impact indices expressed graphically. These indexes resulted in the Percentage of Impact of Technologies - PIT, which characterizes the percentage gain of technology for each of the criteria of the environmental, economic and social dimensions of the productive units. For the environmental dimension, the PIT showed a reduction of -3.73%, where the general index of impact of the activity was 0.95 and after the transition to organic and/or agroecological production it went to 1.29, with a difference of 0.34. In the economic dimension, the PIT was 7.70%, the employment variable with 0.73 and income with 3.89 were the ones that most contributed to this percentage. In the social dimension, the PIT was 7.19%, the most prominent criteria being the consumer with an average of 3.74 and health with an average of 2.99. In this sense, the transition to organic and/or agroecological management, mainly due to the reduction of environmental impacts, provided greater sustainability for agricultural activities in the region.

A new purple-flowered Butia (Arecaceae) from the highlands of the Chapada dos Veadeiros (Brazil)

Background and aims – The highlands of the Chapada dos Veadeiros region comprise one of the largest savannah areas in central Brazil. The region includes large areas of the rare and little-known cerrado rupestre, which is home to numerous endemic species. During research on the Arecaceae flora of Chapada dos Veadeiros, a new species of Butia was discovered, and it is described here. Material and methods – The morphology and anatomy are described based on field collections. Following the default methodology, pinnae and flowers were analysed using LM (freehand cross- and longitudinal sections) and SEM. The new species is compared to its morphologically similar species from the Brazilian central plateau, and an identification key and distribution map were established. Key results – At first sight, the new species Butia soffiae resembles B. archeri, but with staminate and pistillate flowers, which are always purple, different in size, and congested in the rachillae. After close inspection, it is morphologically allied to B. buenopolensis, differing mainly by its glaucous peduncular bract – similar size to the inflorescence, herbaceous peduncle, numerous rachillae, purple floral colour, and inconspicuous staminodes. Differences in leaf anatomy, such as the presence of raphides, a cross-sectionally truncated midrib, and the number of accessory bundles on the midrib, also support the description of a new species. Two structures were recorded for the first time for the genus: squamiform trichomes at the base of the pistil and osmophores on the staminodes. The new species is assessed as Critically Endangered based on the restricted area of occurrence and anthropogenic threats. Conclusion – Butia soffiae is the first endemic Butia species described in Chapada dos Veadeiros. The type population is located near Chapada dos Veadeiros National Park, which is the subject of a bill that aims to reduce its area by 73%. The discovery of this new species reinforces the uniqueness of the local flora and the importance of maintaining the park.

Checklist and molecular phylogenetics reveal three taxonomic novelties in Habenaria (Orchidaceae, Orchidoideae) from Chapada dos Veadeiros, Goiás, Brazil

A comprehensive checklist of Habenaria from Chapada dos Veadeiros, State of Goiás, was performed alongside morphologic and molecular phylogenetic studies, revealing three new taxa endemic to this region. A total of 61 taxa (59 species and two varieties) of Habenaria are recorded for Chapada dos Veadeiros, representing a two-fold increase compared to previous lists and comprising one of the greatest diversities of the genus in Brazil. Of this total, four taxa are locally endemic. Habenaria cultellifolia, until recently known only from the type collection, was rediscovered in the region after 127 years without records and represents this species’ only known extant population. Three proposed new taxa of Habenaria (H. minuticalcar J.A.N. Bat. & Bianch. sp. nov., H. proiteana J.A.N. Bat., A.A. Vale & Bianch. sp. nov., and H. lavrensis var. xanthodactyla J.A.N. Bat. & Bianch. var. nov.) are corroborated by molecular phylogenetic analyses based on nuclear and plastid markers. They are described, illustrated, tentatively assessed as threatened, and compared to phylogenetically and morphologically related species. Since some areas of this mountain range have not yet been floristically sampled, additional taxonomic novelties and new records are still expected in the future.

A new foraging habitat for Chironius vine snakes and a new prey for Chironius brazili in open rocky Cerrado habitats in Central Brazil

ABSTRACT Chironius snakes are typically arboreal or scansorial, usually foraging in trees or forest ground. Herein we report the foraging behavior of the vine snake Chironius brazili while hunting on the large hylid frog Bokermannohyla pseudopseudis on rocky surfaces in open habitats at the Chapada dos Veadeiros, Central Brazil. Snakes were able to locate frogs when they were basking over rock surfaces close to rivers or searching for them on rock crevices even in areas with strong water flux, close to waterfalls. We suggest that scansorial habits and the swimming abilities of Chironius species occurring in rocky montane habitats enable these snakes to feed on these large hylids.

Erythroxylum confertifolium, a new species from Chapada dos Veadeiros National Park, Goiás, Brazil, unveiled by morphology and leaf anatomy

Erythroxylum confertifolium, a new species from the Chapada dos Veadeiros National Park, Goiás, Brazil, is described and illustrate here. It differs from E. campestre and E. parvistipulatum, its most similar congeners, by a set of morphological (e.g. branching appearance of the stem, leaf shape and consistency, numbers of setules of stipules and cataphylls, aspect of the pedicel, size of flower parts and fruits, and aspect of auricles of petals and styles), and leaf anatomical characters (e.g. number of main and accessory vascular bundles and their appearance on the petiole and midrib, aspect of the sheath that surrounds the vascular bundle, presence or absent of papillae, palisade parenchyma/spongy parenchyma ratio, presence or absence of sheath extension in vascular bundles, as well as composition of tissues of the cortex, and fibers types in midrib). Images, conservation assessments, and a distribution map of the new species are presented, as well as images for their morphologically correlated.

Groundwater Level Variation Analysis Using Hydrogeophysical Methods in an Area of Campo Sujo in Cerrado, Chapada dos Veadeiros Region, Goiás

Cerrado’s campo sujo areas have been one of the main focuses of anthropic occupation in the Chapada dos Veadeiros region, Brazil’s Central Plateau, as they are easily accessible flattened areas with less dense vegetation. They are usually associated with wetlands representing excellent water reservoirs and groundwater recharge zones. The environmental characterization and analysis of water level variation are essential to investigate the impacts of human occupation. Hydrogeophysics represents one of the main subsurface research tools due to its easy application and efficiency in identifying the water level, with emphasis on Ground-penetrating radar (GPR), and electrical resistivity tomography (ERT). An analysis of GPR sections with 200, 400, and 900 MHz frequency antennas associated with the resistivity model was carried out to identify structures, and map the groundwater level. The overlapping data compose a hydrogeophysical model with good correlation to direct measurements of water level in a monitoring well, and soil horizons mapped in a trench. The GPR proved to be efficient in mapping the water level, mainly about to the survey with a 400 MHz antenna, shown as a horizontal reflector associated with attenuation portions of the reflection signal, registering in profile the lowering of the water level from 1.68 m in May to 3.35 m in August. The resistivity model showed a good correlation with the variations between the mapped soil horizons. The analysis shows that constructing a hydrogeophysical model is an excellent alternative for identifying the water level, and characterizing the shallow subsurface by applying non-invasive techniques. The study area represents a preserved area of campo sujo, and the research data can be used for comparison with future surveys, in addition to representing a base hydrogeophysics methodology that showed promising results for the physiographic characteristics of the area, which can be replicated in regions of similar geoenvironmental aspects.

Speedy blooming in Cerrado after fire is not uncommon: New records of Cyperaceae species flowering 24 h after burning

AbstractFire‐stimulated flowering has long been a subject of investigation in tropical grasslands and savannas. Still, speedy blooming (i.e. flowering in <24 h after fire) had only been recently described for a single species of Cyperaceae common in Cerrado open ecosystems. Here, we described two new species displaying this unique feature of producing flowers <24 h after fire, suggesting that this fast phenological response might be more common than previously thought. Rhynchospora confusa F.Ballard and Rhynchospora terminalis Nees ex Steud. var. terminalis are two widely distributed species in grasslands and savannas at Chapada dos Veadeiros (a World Natural Heritage by UNESCO). Yet, there is a paucity of herbarium collection for both species and no registration of the quick bloom after fire passage or other aspects of their ecology. Understanding the diversity of phenological patterns and vegetation responses to fire is key to uncovering the functioning and singularities of the tropical open ecosystems.

Vocal repertoire and acoustic variation in a treefrog (Boana ericae) (Amphibia, Anura, Hylidae) endemic to the Chapada dos Veadeiros, Central Brazil

ABSTRACT Despite the great diversity of Brazilian anuran species, there are still many knowledge gaps about the acoustic communication of these animals. Among the species, those classified as ‘Data Deficient’ have the greatest gaps in knowledge on their behavior. This is the case of Boana ericae, a species belonging to the Boana pulchella group, endemic to the Chapada dos Veadeiros National Park region, in the northeast of the state of Goiás, Central Brazil. Three distinct call types (A, B, and C) are currently known for B. ericae, with the type A call associated with attracting reproductive partners and the type C call presenting a territorial function. We recorded the vocalizations of 10 individuals of this species and found the presence of vocalizations composing three new note types (D, E, and F). Our results indicate that air temperature and body condition influenced the acoustic parameters of the advertisement and aggressive calls of this species. We also observed that some acoustic parameters of the advertisement calls can be used for individual recognition for showing greater variation among individuals than intra-individually. Our results add new information regarding the vocal repertoire in this species, expanding their known intra-individual classification of the acoustic parameters.

Stone tools differences across three capuchin monkey populations: food’s physical properties, ecology, and culture

Robust capuchin monkeys (Sapajus) are known for processing mechanically challenging foods, having morphological adaptations to do so. However, several populations go beyond body limitations by using stone tools to expand their food range. Those populations use stones in a variety of ways, goals, and with different frequencies. Stone tool size correlates with the food’s resistance within some populations. However, we have no detailed comparisons to identify if this correlation is the same across populations. This study described and compared stone raw material availability, food’s physical properties (hardness and elasticity), and stone tool weight in three populations of bearded capuchin monkeys (Sapajus libidinosus), including a newly described site (Chapada dos Veadeiros National Park, CVNP). The differences we observed regarding stone tool weight selection among sites were not correlated to the food’s physical properties we analyzed. Lithic resource availability could partly explain some differences in the stone tools used. However, the tool weight differences are larger than the raw material variance across sites, meaning some distinctions are possible behavioral traditions, such as the same fruit (Hymenaea) being processed with bigger than needed tools in CVNP than in the other two sites. Capuchin monkey behavioral variability in stone tool use can be caused by several interacting factors, from ecological to cultural.

The Paepalanthoideae (Eriocaulaceae) of the Chapada dos Veadeiros National Park, Brazil: taxonomic novelties, identification key, and illustrated list of species

The Chapada dos Veadeiros National Park is a conservation unit established to preserve the highest savannahs of Central Brazil and their unique biodiversity. Eriocaulaceae are a relevant and conspicuous family in such high savannahs, but its diversity is poorly known, documented solely in general lists or in isolated efforts aimed at small groups. After a structured series of field expeditions and analysis of specimens from the relevant herbaria, we provide nomenclatural novelties, a first identification key, and an illustrated checklist for the species of Paepalanthoideae (Eriocaulaceae) in the area. We recorded 42 species of Paepalanthoideae from the Chapada dos Veadeiros National Park: Actinocephalus (Körn.) Sano (2 spp.), Comanthera L.B.Sm. (1 sp.), Paepalanthus Mart. (24 spp.), and Syngonanthus Ruhland (15 spp.). Actinocephalus brevifolius Trovó & Echtern. sp. nov. and P. irwinii Trovó & Echtern. sp. nov. are newly described species and P. politus Trovó stat. et nom. nov. is a variety of P. elongatus (Bong.) Körn. raised to the species status with a new name. The generic and specific composition shows predominance of Paepalanthus and Syngonanthus, and with a low representation of Actinocephalus and Comanthera, as expected, outside of the Espinhaço Range. More than 50% of the species (22 spp.) are endemic to the area and 25 species are endemic to Central Brazil, the area being the main center of diversity for dimerous-flowered groups. The non-endemic diversity is a combination of widespread species and marginal distribution of species typical from the Amazon and southeastern savannahs. The species are unevenly distributed in the area, with their occurrence correlated to altitude, water availability, and lithology. We reinforce that the savannahs from Central Brazil are a secondary center of diversity for Eriocaulaceae, playing a central role in the conservation of an unique and irreplaceable piece of its diversity and the Cerrado biome as well.

Novelties in Oocephalus (Hyptidinae, Lamiaceae) from Central Brazil: Two new species from Chapada dos Veadeiros National Park

Abstract— Two new species of Oocephalus (Ocimeae: Hyptidinae), O. griseus and O. campestris, from the Chapada dos Veadeiros National Park (CVNP), in Goiás state, Brazil, are proposed. For each species, description and comments on distribution and taxonomy are provided. Also, a diagnostic key to all Oocephalus species occurring in the state of Goiás and Distrito Federal is provided, as well as a line drawing and illustrated photographs of the new species.

Phyllanthus chapadensis, a new phyllocladiferous Phyllanthus (Phyllanthaceae) from the Chapada dos Veadeiros, Goiás, Brazil

We describe Phyllanthus chapadensis, a new phyllocladiferous species of the genus Phyllanthus probable endemic to the Chapada dos Veadeiros region, Goiás, Brazil, in the Cerrado region. This region is located in Central Brazil with a high number of endemic Angiosperms, unique landscapes, and distinct and peculiar phytophysiognomies. The species described here belongs to Phyllanthus sect. Choretropsis, a Brazilian exclusive group of plants characterized by presenting phylloclades. The new species resembles P. spartioides and P. sarothamnoides, which occur in the Chapada Diamantina, Bahia, Northeastern Brazil, due to its upright shrubby habit, with thin and delicate phylloclades. However, it can be differentiated by the morphological characteristics of phylloclades and flowers. We present the main morphological distinctions between these species, distribution map, illustrations, flowering and fruiting seasons, and a proposal of the conservation status of the new species.

Effects of a megafire on the arbuscular mycorrhizal fungal community and parameters in the Brazilian Cerrado ecosystem

Aim of the study: To evaluate the effects of a mega-fire on the arbuscular mycorrhizal fungi (AMF) community and parameters in soils under Cerrado vegetation. Study area: Chapada dos Veadeiros National Park, Goiás, Brazil. This site suffered the biggest fire in its history on October 10, 2017, with an affected area of 66,000 ha. Material and methods: We analyzed AMF spore density, roots’ mycorrhizal colonization rate, easily extractable glomalin (EEG), as well as the AMF genera present. These parameters were evaluated in burned and unburned areas of five common phytophysiognomies of the region. Main results: Fire presence immediately affected the mycorrhizal community parameters in Cerrado soils, which tended to increase afterwards. The presence of AMF genera did not differ between burned and unburned areas, with Acaulospora, Claroideglomus, Diversispora, Glomus, Funneliformis, Sclerocystis, and Gigaspora being present. The recovery of AMF community conditions in the Cerrado after fire events could also be observed in the mycorrhizal parameters evaluated, as the values of spore density, roots’ mycorrhizal colonization rate, and EEG were similar in the burned and unburned areas. Research highlights: AMF diversity, and especially their community parameters, show great recovery after fire events, since they are crucial in processes like nutrient cycling and soil aggregation.

Hydrochemical and age constraints of the Chapada dos Veadeiros geothermal reservoir, central Brazil

This paper reports the first conceptual model of non-magmatic system in central Brazil, constrained by structural, hydrochemical and isotopic data. The study involved analyses of carbon, oxygen and hydrogen isotopes (14C,18O, 2H and ³H) in addition to the chemical signatures of water samples from natural springs and borehole. Samples were classified into three hydrochemical groups, based on their pH, electric conductivity (EC) and temperature. Group 1 shows the lowest temperature range and lowest pH and EC values (respectively averages of 27 °C, 5.0, and 15 μS/cm); Group 3 shows higher temperature, pH, EC (42 °C, 7.1, and 215 μS/cm); and Group 2 shows intermediate values (average of 38 °C, 6.2 and 80 μS/cm). The conceptual flow model indicates that the recharge area is located in the higher plateau areas and the only recharge source is rainwater. The groundwater flows towards the southwest for 15–25 km up to the São Joaquim fault system, where the hydraulic conductivity contrast, due to different rock types, induces upward flow to the hot springs area. Buoyancy due to heating through deep circulation can also influence the upward flow, however, it is not the main process. The flow path from NE to SW is controlled by secondary brittle structures, related to fractures represented by long lineaments. Environmental radioisotopes of water (3H and 14C) were used to determine the residence time of thermal waters. ³H data indicate that samples MV2 and TOC1 (respectively from groups 2 and 3), are related entirely to the deep thermal reservoir, with no mixing influence between reservoirs. Samples SJ1 and CH3 show ³H values from 0.9 to 0.64 TU, indicating mixture of water from recent cold waters and the deep thermal reservoir. Group 3 samples yielded a raw 14C age of 9270 years, and the most coherent correction model applied was the International Atomic Energy Agency, resulting in an age of 7877 years. Group 2 yielded age of 2280 years and the most consistent correction model applied was the Pearson equation, ensuing an age of 2281 years. Group 1 samples resulted in negative age, interpreted as contamination from external carbon sources likely related to algae. Sample SJ1 (from a deep well) yielded an age of 1,470, and the correction by the Pearson model resulted in age of 1352 years. The δ2H and δ18O data are plotted above the local meteoric water line, indicating enrichment of lighter isotopes. The values measured for the total dissolved solids; electric conductivity and pH are in agreement with the isotopic data interpretations, and with the aquifer mineralogy.

First record and range extension of Corbicula fluminea (Müller, 1774) (Bivalvia, Cyrenidae) in the Chapada dos Veadeiros region, Goiás, Brazil

Corbicula fluminea (Müller, 1774) is an Asian freshwater clam that is widely distributed throughout the world through multiple introductions. Its invasion can cause environmental and economic damage. In Brazil, C. fluminea is recorded in all major hydrographic basins. Here, we report the first record of C. fluminea in the Chapada dos Veadeiros region of Goiás, Brazil. This new record extends the known distribution of this species to a conserved area in the Cerrado biome, towards areas of interest for conservation and integral protection units of the biodiversity.

Museum specimens reveal a rare new characid fish genus, helping to refine the interrelationships of the Probolodini (Characidae: Stethaprioninae)

(Received 7 July 2021; accepted 23 September 2021) Two new characid fish species are described from the upper rio Tocantins basin, Chapada dos Veadeiros, Goiás State, Brazil. Both species were discovered among specimens in museum collections. Relationships of taxa were evaluated in a more comprehensive phylogenetic analysis utilizing the largest dataset available of molecular and morphological data for the family Characidae. The two species were recovered as sister species and described in a new genus, closely related to Erythrocharax and Phycocharax. Dinotopterygium gen. nov. is distinguished from all other characid genera by the unique combination of ten synapomorphies, including the unique anal-fin morphology with a small number of branched anal-fin rays (13-16). Dinotopterygium uniodon sp. nov. and D. diodon sp. nov. differ by the number of tooth series in the premaxillary bone (one or two) and number of tooth cusps (7 or 5). The additional phenotypic variation for a taxonomically informative character within the Characidae through the discovery of new forms has helped to refine the interrelationship of the tribe Probolodini (Characidae: Stethaprioninae). The discovery of these new and possibly critically endangered species emphasizes the importance of museum collections for understanding biodiversity past and present. http://zoobank.org/urn:lsid:zoobank.org:pub:E0FD8207-590B-4FF7-B9CA-FD481A7F8B0E