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Article

The Curious Case of Woodcreepers: Cytogenomic Evidence Based on the Position of NORs

by
Analía del Valle Garnero
1,2,*,
Vitor Oliveira de Rosso
3,
Hybraim Severo Salau
1,2,
Paulo Afonso Rosa de Lara
1,
Victoria Tura
3,
Fabiano Pimentel Torres
1 and
Ricardo José Gunski
1,2,*
1
Grupo de Pesquisa de Diversidade Genética Animal, Universidade Federal do Pampa, São Gabriel 97300-162, Brazil
2
Programa de Pós-graduação em Ciências Biológicas, Universidade Federal do Pampa, Campus São Gabriel, São Gabriel 97300-162, Brazil
3
Coordenação de Biodiversidade, Instituto Nacional de Pesquisas da Amazônia (INPA), Manaus 69067-375, Brazil
*
Authors to whom correspondence should be addressed.
Taxonomy 2025, 5(3), 41; https://doi.org/10.3390/taxonomy5030041
Submission received: 22 April 2025 / Revised: 4 August 2025 / Accepted: 7 August 2025 / Published: 14 August 2025

Abstract

Woodcreepers (Dendrocolaptinae) constitute a subfamily of Neotropical passerines currently recognized as a monophyletic group within Furnariidae. Although Furnariidae is one of the most diverse avian families in the Neotropics, cytogenetic data remain scarce. In this study, we present the first cytogenetic analysis of Lepidocolaptes falcinellus using conventional (Ag-NOR, C-banding) and molecular (hybridization in situ fluorescence—FISH with telomeric and 18S rDNA probes) approaches. The species exhibits a karyotype with 2n = 80 chromosomes, predominantly acrocentric macrochromosomes, and heterochromatin restricted to centromeric regions. Telomeric repeats were confined to terminal regions, and 18S rDNA sites (NORs) were detected on the short arm of chromosome pair 1. This pattern, also observed in other Dendrocolaptinae species, contrasts with the ancestral avian condition of NORs on microchromosomes, suggesting a derived, lineage-specific chromosomal signature. These results support the cytogenetic cohesion of Dendrocolaptinae and reinforce the potential of NOR localization as a phylogenetic marker within the group. Our findings contribute novel cytotaxonomic data that enhance the understanding of chromosomal evolution and systematics in Furnariidae.

1. Introduction

The definition of species can be based on a wide range of information about the taxa under study, including evolutionary history, morphological traits, genetics, natural history, and geographic distribution [1,2]. Additionally, taxonomic research plays a crucial role in identifying distinct evolutionary lineages, enabling the recognition of species potentially at risk of extinction, a vital step for their conservation.
The infraorder Furnariides (Passeriformes) [3], endemic to the Neotropical region, comprises 318 recognized species, accounting for 51% of suboscine Passeriformes and 11% of all Passeriformes. It currently includes seven [4,5] or nine families [3], among which Furnariidae stands out as one of the most remarkable examples of continental-scale adaptive radiation. This family exhibits high rates of cladogenesis and striking morphological diversity, strongly associated with foraging behavior and locomotion [5,6,7].
Initially, woodcreepers (Furnariidae: Dendrocolaptinae) were classified as a separate family, Dendrocolaptidae [8,9,10], closely related to Furnariidae. However, subsequent phylogenetic studies led to their reclassification as a monophyletic subfamily within Furnariidae [3,4,11]. The phylogenetic classification of woodcreepers has undergone significant changes over the past century. Snethlage [12] described the group as a family (Dendrocolaptidae) based on morphological characteristics of Amazonian birds. By the mid-20th century, Bock [13] supported this classification, maintaining woodcreepers as a sister family to Furnariidae. By the late 20th century, Sibley et al. [14] reclassified the group as Dendrocolaptinae, a monophyletic subfamily within Furnariidae, marking the first study to incorporate molecular data in their classification. In the early 21st century, advances in molecular biology refined the subfamily’s classification, highlighting the need for phylogenies based on molecular data [15].
Moyle et al. (2009) [3] proposed a phylogenetic tree in which Dendrocolaptinae was not monophyletic, identifying Glyphorynchus as the most basal lineage among woodcreepers. The most recent and comprehensive study, by Derryberry et al. (2011) [11], analyzed species-level morphological and genetic traits across Furnariidae, confirming the monophyly of Dendrocolaptinae. Currently, Dendrocolaptinae comprises approximately 57 species distributed across 16 or more genera [16].
From a taxonomic perspective, cytogenetic data are critical for understanding evolutionary relationships and genetic mechanisms of evolution. Despite Furnariidae’s considerable species diversity, cytogenetic data remain surprisingly limited. To date, conventional chromosomal banding patterns (C, G, NOR, etc.) are known for only six species: Sittasomus griseicapillus (2n = 82), Lepidocolaptes angustirostris (2n = 82), Glyphorynchus spirurus (2n = 80), Synallaxis frontalis (2n = 82), Cranioleuca obsoleta (2n = 82), and Syndactyla rufosuperciliata (2n = 82) [17,18,19,20]. Chromosomal painting using Gallus gallus (GGA) and Burhinus oedicnemus (BOE) probes has only been applied to S. frontalis and G. spirurus [18,19]. In Dendrocolaptes platyrostris, S. frontalis, C. obsoleta, and S. rufosuperciliata, repetitive sequence probes have also been used to map these sequences in their respective karyotypes [20,21].
rDNA genes are essential for ribosome biogenesis, encoding rRNAs [22,23]. They are organized into two main clusters: 45S rDNA (comprising 18S, 5.8S, and 28S genes, along with ITS and ETS spacers) and 5S rDNA (including the 5S gene and an intergenic spacer) [24,25]. In eukaryotic genomes, these sequences occur as multiple tandem repeats on chromosomes.
An intriguing cytogenetic pattern observed in these studies is the localization of 45S rDNA sites, which are typically confined to a single pair of microchromosomes in most bird species, a configuration considered ancestral according to the Nishida-Umehara hypothesis [26]. This conclusion is supported by the conservation of this arrangement in multiple Paleognathae species and many Neognathae, indicating its persistence throughout evolution. In contrast, the presence of 45S rDNA on macrochromosomes, observed in some avian orders, is considered a derived state resulting from fusion events between distinct micro- and macrochromosomes [21].
Although Furnariidae is a highly diverse family, cytotaxonomic studies remain scarce, limiting our understanding of chromosomal evolution in this group. The presence of rDNA on macrochromosomes reflects chromosomal rearrangements, such as fusions, suggesting a derived state that may have shaped their evolutionary trajectory. This study presents the first cytogenetic analysis of Lepidocolaptes falcinellus (Dendrocolaptinae), including Ag-NOR staining, C-banding, and hybridization in situ fluorescence (FISH) with telomeric (TTAGGG)5 and rDNA probes. Notably, an atypical rDNA hybridization pattern was observed on the macrochromosomes. We review the phylogenetic placement of species and propose a karyotype evolution model based on NORs within Furnariidae. By characterizing the species’ karyotype and analyzing heterochromatin distribution and rDNA loci, we provide new insights into evolutionary patterns within Dendrocolaptinae. Comparisons with other species in the group allow us to assess the conservation and variability of chromosomal traits, offering valuable information on evolutionary and taxonomic processes.

2. Material and Methods

2.1. Specimens Analyzed and Chromosomal Preparations

Two individuals of the species Lepidocolaptes falcinellus (1, 1♂) were collected in the municipalities of Caçapava do Sul and Santana da Boa Vista, located in the Pampa biome in the state of Rio Grande do Sul, Brazil. The specimens were captured using mist nets, following protocols approved by the Ethics Committee on Animal Use (CEUA 019/2020, 024/2023) and the Biodiversity Authorization and Information System (SISBIO 61047-3, 33860-2, and 81564-1). Metaphase chromosomes were obtained through direct bone marrow cell culture, as described by Garnero and Gunski [27]. Chromosome preparation involved exposing cultures to colchicine (0.05%) for 1 h, followed by hypotonic treatment with 0.075 M KCl and cell fixation in methanol/acetic acid (3:1).

2.2. Conventional Cytogenetics

To determine the diploid number, 30 metaphases per specimen were analyzed. Karyotype characterization followed the nomenclature proposed by Guerra [28]. The identification of regions rich in constitutive heterochromatin was performed according to Sumner [29], with modifications. Slides were incubated at 60 °C for 1 h, treated with 0.2 N HCl at 42 °C for 10 min, and subsequently with 5% Ba(OH)2 at 42 °C for 3 min. They were then subjected to treatment with 2× SSC solution at 60 °C for 1 h and 30 min. Identification of chromosomal pairs bearing nucleolar organizer regions (Ag-NORs) was performed following the Howell and Black method [30], with modifications. For this, a drop of colloidal solution was applied to the slide, followed by the addition of three drops of 50% silver nitrate. Slides were covered with coverslips and incubated in a humid chamber at 60 °C inside a closed Petri dish. All analyses were conducted using conventional staining with 5% Giemsa solution in phosphate buffer (pH 6.8).

2.3. Repetitive DNA Mapping by FISH

Telomeric probes (TTAGGG)5 and 18S rDNA probes, amplified by polymerase chain reaction (PCR), were used. The PCR was prepared with 1× PCRbuffer, 2.5 mM MgCl2, 0.2 mM of each dNTP, 0.4 μM of each primer (forward and reverse), 2.5 U of Taq DNA polymerase, and 25 ng of template DNA (nuclear DNA from G. gallus—Aves, Galliformes, Phasianidae). The PCR conditions included an initial denaturation at 95 °C for 2 min, followed by 35 cycles of denaturation at 95 °C for 30 s, annealing at 57 °C for 1 min, and extension at 72 °C for 1 min and 30 s, with a final extension step at 72 °C for 5 min [31]. Amplification of the telomeric probes was performed with the primers (TTAGGG)5 and (CCCTAA)5, without template DNA, following the PCR conditions described by Kretschmer et al. (2022) [32]. For the 18S rDNA probe, specific primers were designed for conserved loci in the Aves class, using nuclear DNA from Gallus gallus (Aves, Galliformes, Phasianidae), with the aim of detecting the 45S rDNA site (in press). Probes were labeled with Aminoallyl-dUTP ATTO-550 (red) via Nick translation (Jena Bioscience, Jena, Germany). The FISH protocol was performed as described by [32]. To identify the pattern of each probe, 20 metaphases were analyzed. All FISH experiments were repeated at least three times to confirm the labeling. Images were captured using an Olympus BX53 microscope (Olympus Corporation, Ishikawa, Japan) coupled with a CoolSNAP camera and processed with CellSens Standard software 1.12. Karyotype assembly was performed using GIMP software 3.0.4.

2.4. Molecular Phylogeny

Mitochondrial (mtDNA) and nuclear DNA sequences were obtained from GenBank for 285 species, including all 71 genera from the Furnariidae family, incorporating data from multiple published studies, including [3,11], as well as additional publicly available sequences in the National Center for Biotechnology Information database. Six species (Tityra semifasciata, Tyrannus tyrannus, T. melancholicus, Melanopareia torquata, Terenura sharpei, and Formicarius colma) from five different closely related families [11] were used as an outgroup. The dataset was curated to maximize taxonomic coverage across Furnariidae while using high sequence quality and alignment compatibility.
Multiple sequence alignments were performed using MAFFT v7.505 [33]. Alignments were manually inspected in AlliView [34] to ensure consistency. The dataset consisted of four gene partitions [35], including mitochondrial and nuclear loci: beta-fibrinogen intron 7 (906 bp), recombinase-activating gene 2 (1152 bp), cytochrome oxidase subunit II (684 bp), and NADH dehydrogenase subunit 3 (351 bp). The total concatenated alignment length was 3093 base pairs. Sequence concatenation was performed using FASTconCAT-G v1.06.1 [36], maintaining partitioned data for downstream analyses. All the sequences used in the phylogeny were full-length genes, verified through alignment with other known sequences; the only exception was the nuclear beta-fibrinogen-7 sequence that used the seventh exon, plus, all genes used were retrieved and are available on NCBI.
We determined the optimal substitution models for each gene partition using ModelFinder [37] as implemented in I.Q-TREE V2.0.7 [38]. For each gene alignment, ModelFinder evaluated a comprehensive set of candidate models using Bayesian Information Criterion (BIC) to identify the best balance between model fit and complexity. Analysis determined the following best-fit models: beta-fibrinogen intron 7 was best described by the TVM+F+R3, recombinase-activating gene 2 fit the model HKY+F+R3, cytochrome oxidase subunit II was best explained by TIM2+F+I+G4, and NADH dehydrogenase subunit 3 was optimally modeled by TVM+F+I+G4. Selected models were subsequently applied in maximum likelihood phylogenetic reconstructions with 10,000 ultrafast bootstrap replicates [39] to ensure accurate evolutionary inference.
Phylogenetic trees were visualized and annotated using the Interactive Tree Of Life (iTOL) v6 web platform [40]. Newick-format trees generated from IQ-TREE analyses were uploaded to iTOL, where branch colors, node labels, and bootstrap support values were customized to enhance interpretability.

3. Results

3.1. Cytogenetic Analysis

The karyotype of L. falcinellus consists of 2n = 80 chromosomes, divided into 8 to 10 pairs of macrochromosomes and 30 to 32 pairs of microchromosomes (Figure 1). Pairs 1 and 3 are submetacentric, pairs 2, 4 and 5 are acrocentric, and the remaining pairs, including the sex pair, are telocentric. The Z chromosome exhibits a size comparable to the fourth chromosomal pair, while the W chromosome is similar in size to the sixth pair. Nucleolus organizer regions (NORs) were localized on the short arms of the first chromosome pair (Figure 2a), where an association between homologs was observed in 10% of analyzed metaphases (n = 200; Figure 2b). Additionally, hybridization with the 18S rDNA probe confirmed the localization of the NORs on the short arm of the first chromosome pair (Figure 2c). Constitutive heterochromatin was detected in the centromeric regions of the chromosomes, with the W sex chromosome being entirely heterochromatic (Figure 2d,e). FISH with telomeric sequence probes revealed signals at the chromosomal termini (telomeres) (Figure 2f).

3.2. Phylogeny

The maximum likelihood analysis of the concatenated dataset using IQ-TREE yielded a well-resolved phylogeny with robust node support (Figure 3). Ultrafast bootstrap analysis inferred relationships, with most nodes being strongly supported, with several nodes achieving bootstrap values above 90. However, specific nodes exhibited lower support: within the Asthenes clade, the node connecting Asthenes coryi to its sister grouping registered a bootstrap value of 30.
Three major clades were clearly delineated, as formerly reported by Derryberry et al. [11]. The first clade, Sclerurinae, comprises two genera, Sclerurus and Geositta, followed by the Dendrocolaptinae subfamily, formed by 15 genera, whereas the most well-represented clade is the subfamily Furnariinae, comprising 55 different genera.

4. Discussion

Subfamilies Dendrocolaptinae and Furnariinae exhibit marked differences in lifestyle and ecology, reflecting adaptations to distinct ecological niches. Dendrocolaptinae comprises arboreal species specialized in climbing tree trunks and branches, using stiff tails for support and foraging for insects beneath tree bark. Many species participate in mixed-species flocks, taking advantage of prey flushed out by other birds. In contrast, Furnariinae displays greater ecological diversity, encompassing terrestrial, shrub-dwelling, and arboreal species with a variety of foraging strategies. Moreover, Furnariinae stands out for its diverse reproductive behaviors, with several species building elaborate nests, such as the mud nests of the genus Furnarius, whereas members of Dendrocolaptinae predominantly nest in natural cavities.
Cytogenetic comparisons among Furnariidae species reveal limited variation in diploid number, ranging from 80 to 82 chromosomes, yet a remarkable diversity in macrochromosome morphology [17,18,19,20]. Lepidocolaptes falcinellus and Glyphorynchus spirurus, both belonging to the subfamily Dendrocolaptinae, exhibit a diploid number of 2n = 80, which is considered ancestral for birds. However, they differ notably in karyotypic structure: while L. falcinellus possesses a combination of submetacentric (pairs 1 and 3), acrocentric (pairs 2, 4, and 5), and telocentric chromosomes (remaining macrochromosomes and sex chromosomes), G. spirurus exhibits a karyotype composed exclusively of acrocentric macrochromosomes, including the sex chromosomes (Table 1) [19].
In species with 2n = 82, chromosomal morphological variation is more complex. L. angustirostris exhibits a predominance of acrocentric chromosomes (pairs 1, 3, and 4 and the Z sex chromosome) and telocentric chromosomes (pairs 2 and 5–10 and the W chromosome). S. griseicapillus, in turn, shows a higher frequency of telocentric chromosomes (pairs 1, 2, and 4–10), while pair 3 is acrocentric. The sex chromosome configuration is similar to the one observed in L. angustirostris [17]. S. rufosuperciliata differs by exhibiting a greater number of submetacentric chromosomes (pairs 2–5), while pairs 1, 6, and 7 are acrocentric. The Z chromosome is submetacentric, and the W chromosome was not described. C. obsoleta shares several characteristics with S. rufosuperciliata, displaying the same morphology for pairs 1–7. The main difference lies in pairs 8–10, which are submetacentric, and in the Z chromosome, which is acrocentric [20]. Finally, S. frontalis stands out for its higher morphological diversity, with telocentric chromosomes (pairs 1, 3, 9, and 10), acrocentric chromosomes (pairs 2 and 5–7), and a submetacentric pair 4. Additionally, its sex chromosomes differ from those of the other species, as both are metacentric (Table 1) [18,20].
The expected avian pattern was observed, with constitutive heterochromatin predominantly localized in the centromeric regions. Complete heterochromatinization of the W chromosome aligns with well-documented findings in birds possessing a ZW sex determination system. Structural conservation of telomeric sequences throughout avian evolution is evidenced by their characteristic distribution pattern. As anticipated, these sequences were detected at the terminal regions of both the short and long arms of the chromosomes [41].
In species from the broader Furnariidae family, such as S. frontalis, S. rufosuperciliata, and C. obsoleta, the 18S rDNA sequences are located on a pair of microchromosomes [20]. This pattern reflects the ancestral condition, which has been preserved across multiple avian lineages and is associated with a conserved karyotypic structure.
This evolutionary trend is also evident in other avian orders. While the ancestral positioning of NORs on microchromosomes is well documented, some groups exhibit derived patterns. In Accipitriformes (e.g., Pandion haliaetus, Morphnus guianensis) [42,43], Charadriiformes (B. oedicnemus) [44], Cuculiformes (Piaya cayana and Guira guira) [21], and Piciformes (Colaptes campestres and C. melanochloros) [45], for instance, rDNA sequences are found on macrochromosomes.
Localization of the NORs on the short arm of the first pair of macrochromosomes in G. spirurus, considered an early-diverging species [3], suggests a chromosomal fusion event that transferred NORs from microchrosomes. This rearrangement may have been a pivotal evolutionary mechanism underlying the conserved karyotypic pattern observed in the Dendrocolpatinae subfamily.
Alternatively, the presence of nucleolar organizer regions (NORs) on the short arm of the same pair of macrochromosomes in S. griseicapillus (Figure 4) [17] suggests that an independent chromosomal rearrangement may have occurred within this species following the ancestral microchromosome fusion. This deviation from the pattern observed in closely related taxa may be the result of a pericentric inversion, which would have repositioned the NORs without altering the chromosome pair itself. Such a rearrangement highlights the potential for microstructural chromosomal changes to contribute significantly to karyotypic diversification within Dendrocolaptinae, emphasizing the dynamic nature of genome organization even among phylogenetically proximate species.
This event differentiates S. griseicapillus from other members of the subfamily, while still maintaining the conservation of rDNA sequences on the first chromosome pair, thus reinforcing its phylogenetic placement within Dendrocolaptinae (Figure 3) [17].
During the analyses, metaphases were observed, in which the first pair of macrochromosomes appeared to be associated. This phenomenon is attributed to the high transcriptional activity of 18S rDNA genes during the cell cycle, which can leave residual transcriptional signals [21]. As a result, chromosomes bearing the NORs/18S rDNA may remain aligned, often displaying a “mirror-like” appearance during the metaphase. In L. falcinellus, for instance, the short arms of the first chromosome pair exhibit marked proximity (Figure 2b).
Presence of these sequences on the p arm of chromosome pair 1 in L. falcinellus, L. angustirostris, G. spirurus, and D. platyrostris, as well as on the q arm of pair 1 in S. griseicapillus, reveals a consistent pattern within the Dendrocolaptinae [17,18,19,20,21]. This pattern suggests a shared chromosomal feature supporting phylogenetic analyses, grouping these species based on the conserved positioning of 18S rDNA sequences on macrochromosomes.
Therefore, the presence of 18S rDNA sequences on the first chromosome pair in Dendrocolaptinae reinforces the phylogenetic relationship among these species (Figure 3). Comparative analyses across avian orders reveal a consistent evolutionary pattern, in which the relocation of rDNA sites to macrochromosomes is associated with structural chromosomal rearrangements. These variations provide valuable insights into the evolutionary dynamics of avian karyotypes and highlight the cytogenetic diversity that emerged throughout the evolutionary history of birds.
Phylogenetic reconstruction analysis of the Furnariidae corroborates the monophyly of three major clades, Sclerurinae, Dendrocolaptinae, and Furnariinae, with high nodal support, reinforcing taxonomic boundaries previously established by prior molecular and morphological analyses, confirming their evolutionary divergence and taxonomic distinctiveness. Among Dendrocolaptinae, the conserved localization of the 45S rDNA cluster on the first pair of macrochromosomes in G. spirurus, S. griseicapilus, L. angustirostris, L. falcinellus, and D. platyrostris [17,19,21] underscores a shared cytogenetic signature within this clade. In contrast, the microchromosal placement of this cluster in the Furnariinae species S. rufosuperciliata, C. obsoleta, and S. frontalis [18,20] aligns with their phylogenetic divergence from Dendrocolaptinae, suggesting subfamily-specific evolutionary trajectories in genome organization. These differential rDNA patterns reinforce the deep evolutionary split between Dendrocolaptinae and Furnariinae inferred from molecular phylogenies, with karyotypic conservation likely reflecting ancestral states or stabilizing selection in Dendrocolaptinae, while microchromosomal positioning in Furnariinae may signal lineage-specific genomic reorganization. Lack of 45S rDNA data for Sclerurinae provides a framework to investigate potential correlations between their phylogenetic distinctiveness and unique cytogenetic features.

5. Conclusions

The differential distribution of 18S rDNA clusters between macro- and microchromosomes in Furnariidae species highlights the cytogenetic complexity underlying the group’s evolutionary history. Localization of rDNA sequences on macrochromosomes in Dendrocolaptinae likely reflects chromosomal rearrangements such as fusions or inversions, suggesting a derived state possibly become fixed through selective or functional constraints. This pattern, recurrent across multiple Dendrocolaptinae species, reinforces their phylogenetic cohesion and may serve as a valuable cytogenomic marker.
In contrast, the conserved microchromosomal location of rDNA clusters in Furnariinae supports the ancestral condition and reflects a distinct evolutionary trajectory within Furnariidae. These differences provide compelling evidence of subfamily-specific chromosomal evolution and may be linked to broader lineage-specific adaptations in genome organization.
Therefore, our findings contribute to a deeper understanding of chromosomal evolution in Neotropical passerines, emphasizing the relevance of rDNA loci in comparative cytogenetics and avian systematics. Future studies including Sclerurinae and additional Dendrocolaptinae taxa will be essential to evaluate the broader applicability of this chromosomal marker across Furnariidae.

Author Contributions

A.d.V.G. and R.J.G. contributed to the study conception and design. The methodology was performed by V.O.d.R. and P.A.R.d.L. Formal analysis, data curation, and investigation were performed by V.O.d.R. and H.S.S. Visualization was performed by V.O.d.R. and P.A.R.d.L. The original draft was written by V.O.d.R. and H.S.S. Writing—review and editing was performed by V.O.d.R., V.T., F.P.T., R.J.G., and A.d.V.G. Funding was obtained by R.J.G. and A.d.V.G. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Finance Code 001 (V.O.R.); the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Grant Number 407285/2021-0 (A.D.V.G.); and the Programa de Apoio à Fixação de Jovens Doutores no Brasil—EDITAL FAPERGS/CNPq 07/2022 (A.D.V.G.).

Institutional Review Board Statement

This study protocol was reviewed and approved by the Ethics Committee on the Use of Animals, approval number (CEUA 019/2020, 024/2023), and Biodiversity Authorization and Information System (SISBIO 61047-3, 33860-2 e 81564-1).

Data Availability Statement

All data generated or analyzed during this study are included in this article. Further enquiries can be directed at the corresponding author.

Conflicts of Interest

The authors have no conflicts of interest to declare.

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Figure 1. Karyotype of a female Lepidocolaptes falcinellus (2n = 80). Pairs 1 and 2 are acrocentric, pair 3 is submetacentric, and all remaining chromosomes, including both macrochromosomes and microchromosomes, are telocentric. The sex chromosomes are acrocentric, with the Z chromosome similar in size to pair 4 and the W chromosome similar in size to pair 6. Scale bar = 10 μm.
Figure 1. Karyotype of a female Lepidocolaptes falcinellus (2n = 80). Pairs 1 and 2 are acrocentric, pair 3 is submetacentric, and all remaining chromosomes, including both macrochromosomes and microchromosomes, are telocentric. The sex chromosomes are acrocentric, with the Z chromosome similar in size to pair 4 and the W chromosome similar in size to pair 6. Scale bar = 10 μm.
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Figure 2. Chromosome banding patterns in Lepidocolaptes falcinellus: (a) NORs; (b) associated NORs; (c) 18S rDNA probe detected by FISH; (d,e) constitutive heterochromatin; (f) telomeric probes detected by FISH. Chromosomes bearing NORs/18S rDNA signals (ac) and sex chromosomes (d,e) are indicated. Scale bar = 10 μm.
Figure 2. Chromosome banding patterns in Lepidocolaptes falcinellus: (a) NORs; (b) associated NORs; (c) 18S rDNA probe detected by FISH; (d,e) constitutive heterochromatin; (f) telomeric probes detected by FISH. Chromosomes bearing NORs/18S rDNA signals (ac) and sex chromosomes (d,e) are indicated. Scale bar = 10 μm.
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Figure 3. Maximum likelihood phylogenetic inference including 285 species of the Furnariidae family, grouped into three major clades. Bootstrap values range from 30 (orange) to 100 (cyan).
Figure 3. Maximum likelihood phylogenetic inference including 285 species of the Furnariidae family, grouped into three major clades. Bootstrap values range from 30 (orange) to 100 (cyan).
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Figure 4. Partial phylogenetic tree of the Dendrocolaptinae subfamily. Arrows indicate the first pair of macrochromosomes and the position of the NORs (nucleolus organizer regions) in each highlighted species.
Figure 4. Partial phylogenetic tree of the Dendrocolaptinae subfamily. Arrows indicate the first pair of macrochromosomes and the position of the NORs (nucleolus organizer regions) in each highlighted species.
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Table 1. Diploid number, chromosome morphology, and NOR/18S rDNA-bearing chromosomal pairs in Furnariidae species.
Table 1. Diploid number, chromosome morphology, and NOR/18S rDNA-bearing chromosomal pairs in Furnariidae species.
L. falcinellusL. angustirostrisS. griseicapillusG. spirurusS. frontalisS. rufosuperciliataC. obsoleta
2n = 802n = 822n = 822n = 802n = 822n = 822n = 82
SMATATAA
ATTAASMSM
SMAAATSMSM
AATASMSMSM
ATTAASMSM
TTTAAAA
TTTAAAA
TTTAM-SM
TTTAT-SM
10ºTTTAT-SM
ZTAAAMSMA
WTTTAM--
NORs/18S1st pair
p arm
1st pair
p arm
1st pair
q arm
1st pair
p arm
1 pair of micro1 pair of micro1 pair of micro
ReferencesPresent study[17][19][18,20][20]
In the species D. platyrostris, only the localization of the 18S rDNA sequence was analyzed, which was identified on the p arm of the first pair. A: acrocentric; M: metacentric; micro: microchromosome; SM: submetacentric; T: telocentric.
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Garnero, A.d.V.; de Rosso, V.O.; Salau, H.S.; Rosa de Lara, P.A.; Tura, V.; Pimentel Torres, F.; Gunski, R.J. The Curious Case of Woodcreepers: Cytogenomic Evidence Based on the Position of NORs. Taxonomy 2025, 5, 41. https://doi.org/10.3390/taxonomy5030041

AMA Style

Garnero AdV, de Rosso VO, Salau HS, Rosa de Lara PA, Tura V, Pimentel Torres F, Gunski RJ. The Curious Case of Woodcreepers: Cytogenomic Evidence Based on the Position of NORs. Taxonomy. 2025; 5(3):41. https://doi.org/10.3390/taxonomy5030041

Chicago/Turabian Style

Garnero, Analía del Valle, Vitor Oliveira de Rosso, Hybraim Severo Salau, Paulo Afonso Rosa de Lara, Victoria Tura, Fabiano Pimentel Torres, and Ricardo José Gunski. 2025. "The Curious Case of Woodcreepers: Cytogenomic Evidence Based on the Position of NORs" Taxonomy 5, no. 3: 41. https://doi.org/10.3390/taxonomy5030041

APA Style

Garnero, A. d. V., de Rosso, V. O., Salau, H. S., Rosa de Lara, P. A., Tura, V., Pimentel Torres, F., & Gunski, R. J. (2025). The Curious Case of Woodcreepers: Cytogenomic Evidence Based on the Position of NORs. Taxonomy, 5(3), 41. https://doi.org/10.3390/taxonomy5030041

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