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Monoculture tree plantations reduces landscape heterogeneity and the number and diversity of habitats available for species. Physical-chemical changes in soil may affect the ponds where tadpoles develop. This work aimed to study the effect on tadpoles of two species of frogs, Leptodactylus luctator (Ll) and Odontophrynus reigi (Or) exposed to soils from a pine plantation (PP), which were compared to tadpoles exposed to soils from Atlantic Forest, the native forest (NF). The impact of soils from both places on growth, development, antioxidant system and genetic damage of Ll and Or tadpoles were observed. A composite sample (5 kg) of soil was taken from the top 10 cm stratum in a 200 m transect in each site, with random plots of 50x50cm. In collected soil samples Organic Matter (OM), Organic Carbon (OC), and Total Nitrogen (TN) were determined. We conducted laboratory experiments, from 23 until 38 Gosner stages. During the experiment, pH and ammonium in the water were determined. Soil from NF presented higher content of OM, OC and TN, and water pH in PP was 0.2 units lower than in NF. Both species showed ≈60 % increase of catalase activity in PP, and ≈40 % increase of lipid peroxidation in NF. Ll tadpoles presented 10 times higher protein oxidation in PP than in NF, but Gosner stage was higher in NF. In NF the higher OM and OC in both species causes the increase of lipid peroxidation; and Ll responds to a stressor in PP that in Or is not observed. Or presented lower stress response towards PP soils, which indicates a tolerance towards this soil. The changes observed in soil chemistry, although not big from a physical-chemical point of view, affects the growth, development and oxidative stress of two species of anuran tadpoles from the NF, which can affect future populations and anuran diversity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Intending to increase the knowledge about cytogenetics of Physalaemus and the sparsely studied P. gracilis group, we analyzed the karyotypes of P. carrizorum, P. gracilis, P. lisei, and P. sp. aff. gracilis. We studied chromosome morphology, heterochromatin patterns, Ag-NORs location and mapped the repetitive DNA sequence PcP190. All species showed diploid karyotypes composed of 22 bi-armed chromosomes and similar C- bands and Ag-NOR patterns. C-bands were mainly centromeric and pericentromeric; non-centromeric C-bands were detected on the telomeres of pair 1 in P. lisei, although polymorphic, and interstitially on pair 10 of P. gracilis. This last character is useful to distinguish P. gracilis from its sibling species P. sp. aff. gracilis. The Ag-NOR sites were detected on the long arms of chromosome pair 8 but with a variable position among species. Clusters of PcP190 showed centromeric and pericentromeric positions coincident with conspicuous C-bands, on pairs 2 and 9 in P. gracilis and P. sp. aff. gracilis, pair 3 in P. carrizorum, and pair 7 in P. lisei. These results significantly increase the knowledge about Physalaemus cytogenetics and encourage further studies on the satellite PcP190 in other genera of Leiuperinae to better understand its taxonomic distribution and the evolutionary dynamics.

Phylogeographic studies primarily focus on the major role of landscape topography in driving lineage diversification. However, populational phylogeographic breaks may also occur as a result of either niche conservatism or divergence, in the absence of geographic barriers to gene flow. Furthermore, these two factors are not mutually exclusive and can act in concert, making it challenging to evaluate their relative importances on explaining genetic variation in nature. Herein, we use sequences of two mitochondrial and four nuclear genes to investigate the timing and diversification patterns of species pertaining to the Leptodactylus latrans complex, which harbors four morphologically cryptic species with broad distributions across environmental gradients in eastern South America. The origin of this species complex dates back to the late Miocene (ca. 5.5 Mya), but most diversification events occurred synchronically during the late Pleistocene likely as the result of ecological divergence driven by Quaternary climatic oscillations. Further, significant patterns of environmental niche divergences among species in the L. latrans complex imply that ecological isolation is the primary mode of genetic diversification, mostly because phylogenetic breaks are associated with environmental transitions rather than topographic barriers at both species and populational scales. We provided new insights about diversification patterns and processes within a species complex of broadly and continuously distributed group of frogs along South America., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Cytogenetic analyses were performed on specimens of Leptodactylus bufonius from different localities in Argentina. Mitotic chromosomes were studied with Giemsa and differential staining techniques (Ag-NOR, C-banding, and CMA3/DAPI) and fluorescence in situ hybridization with the 18S DNAr probe. All specimens showed karyotypes with 2n = 2x = 22 and FN = 44. Secondary constrictions were present in the long arm of chromosome pair 8, coincident with Ag-NOR and hybridization signals of the 18S DNAr probe. The C-banding technique evidenced an important amount of heterochromatin with a sex-linked pericentromeric band in the short arm of chromosome pair 4. This heterochromatic band was heteromorphic in males but present in both homologues of females, and it was CMA3 positive (DAPI negative) at fluorescence staining. The occurrence of heteromorphic XY sex chromosomes in L. bufonius is the second known case in Leptodactylus and the fifth within the speciose family Leptodactylidae.

In this paper we present a phylogenetic analysis of the treefrogs of the Boana pulchella Group with the goals of (1) providing a rigorous test of its monophyly; (2) providing a test of relationships supported in previous studies; and (3) exploring the relationships of the several species not included in previous analyses. The analyses included>300 specimens of 37 of the 38 species currently included in the group, plus 36 outgroups, exemplars of the diversity of Boana and the other genera of the hylid tribe Cophomantini. The dataset included eight mitochondrial genes (12S, 16S, CytB, COI, ND1, tRNA Ile , tRNA Leu , and tRNA Val ) and five nuclear genes (RHO, TYR, RAG-1, CXCR4, SIAH1). The phylogenetic analyses recover the monophyly of the B. pulchella Group with lower support than previous studies, as a result of the inclusion of the B. claresignata Group, which is recovered as its sister taxon. Within the B. pulchella Group, the inclusion of almost all species of the group had little impact on previous notions of its phylogeny, except for the rejection of the hypothesized B. polytaenia Clade (B. goiana and B. phaeopleura are nested in the clade here called the B. prasina Clade), which is redefined. Phylogenetic support is strong for five major clades, which collectively include all but three of the species sampled: the B. balzani Clade (B. aguilari, B. balzani, B. gladiator, B. melanopleura, B. palaestes), the redefined B. polytaenia Clade (B. botumirim, B. buriti, B. cipoensis, B. jaguariaivensis, B. leptolineata, B. polytaenia, B. stenocephala, and two undescribed species), the B. prasina Clade (B. bischoffi, B. caingua, B. cordobae, B. goiana, B. guentheri, B. marginata, B. phaeopleura, B. prasina, B. pulchella, and one undescribed species), the B. riojana Clade (B. callipleura, B. marianitae, B. riojana), and the B. semiguttata Clade (B. caipora, B. curupi, B. joaquini, B. poaju, B. semiguttata, B. stellae, and two undescribed species). The monophyly of the B. prasina + B. riojana Clades, and that of the B. polytaenia + B. semiguttata Clades are well-supported. The relationships among these two clades, the B. balzani Clade, B. ericae + B. freicanecae, and B. cambui (representing the deepest phylogenetic splits within the B. pulchella Group) are recovered with weak support. We discuss the phenotypic evidence supporting the monophyly of the B. pulchella Group, and the taxonomy of several species, identifying three new synonyms of Boana polytaenia, one new synonym of Boana goiana, and one new synonym of B. riojana., (Copyright © 2020 Elsevier Inc. All rights reserved.)

The South American and West Indian Casque-headed Treefrogs (Hylidae: Hylinae: Lophyohylini) include 85 species. These are notably diverse in morphology (e.g. disparate levels of cranial hyperossification) and life history (e.g. different reproductive modes, chemical defences), have a wide distribution, and occupy habitats from the tropical rainforests to semiarid scrubland. In this paper, we present a phylogenetic analysis of this hylid tribe based on sequence fragments of up to five mitochondrial (12S, 16S, ND1, COI, Cytb) and six nuclear genes (POMC, RAG-1, RHOD, SIAH, TNS3, TYR). We included most of its species (> 96%), in addition to a number of new species. Our results indicate: (i) the paraphyly of Trachycephalus with respect to Aparasphenodon venezolanus; (ii) the nonmonophyly of Aparasphenodon, with Argenteohyla siemersi, Corythomantis galeata and Nyctimantis rugiceps nested within it, and Ap. venezolanus nested within Trachycephalus; (iii) the polyphyly of Corythomantis; (iv) the nonmonophyly of the recognized species groups of Phyllodytes; and (v) a pervasive low support for the deep relationships among the major clades of Lophyohylini, including C. greeningi and the monotypic genera Itapotihyla and Phytotriades. To remedy the nonmonophyly of Aparasphenodon, Corythomantis, and Trachycephalus, we redefined Nyctimantis to include Aparasphenodon (with the exception of Ap. venezolanus, which we transferred to Trachycephalus), Argenteohyla, and C. galeata. Additionally, our results indicate the need for taxonomic work in the following clades: (i) Trachycephalus dibernardoi and Tr. imitatrix; (ii) Tr. atlas, Tr. mambaiensis and Tr. nigromaculatus; and (iii) Phyllodytes. On the basis of our phylogenetic results, we analyzed the evolution of skull hyperossification and reproductive biology, with emphasis on the multiple independent origins of phytotelm breeding, in the context of Anura. We also analyzed the inter-related aspects of chemical defences, venom delivery, phragmotic behaviour, co-ossification, and prevention of evaporative water loss., (© The Willi Hennig Society 2020.)

The hyline tribe Lophyohylini includes 87 species of treefrogs, of which cytogenetics aspects have been studied in less than 20% of them. In order to evaluate the evolution of some of its chromosome characters (NOR position, C-bands, and DAPI/CMA3 bands), we studied the karyotypes of 21 lophyohylines, 16 of them for the first time, and analyzed them in a phylogenetic context. Most species showed similar karyotypes regarding chromosome number (2n = 24) and morphology (FN = 48), excepting Phyllodytes edelmoi and Osteocephalus buckleyi with 2n = 22 (FN = 44) and 2n = 28 (FN = 50), respectively. The NOR location was variable among species and provided valuable phylogenetic information. This marker was located in pair 11 in all species of Trachycephalus, Itapotihyla langsdorffii, and Nyctimantis arapapa, representing the plesiomorphic condition of Lophyohylini. Besides, other apomorphic states were recovered for the clades comprising N. rugiceps and N. siemersi (NOR in pair 5), and Dryaderces pearsoni, Osteocephalus, and Osteopilus (NOR in pair 9). Phyllodytes presented variation for NORs position; they were in pair 2 in P. edelmoi, pair 7 in P. melanomystax, and pair 8 in P. gyrinaethes and P. praeceptor. Polymorphisms in size, number, and activity of this marker were observed for N. siemersi, Osteocephalus fuscifacies, and some species of Trachycephalus. Remarkably, in N. siemersi NORs were detected on a single chromosome in the two specimens studied by this technique, raising the question of how this complex polymorphism is maintained. Interstitial telomeric sequences were found in P. edelmoi, P. melanomystax, and Osteocephalus buckleyi, and their presence seems to be not related to the chromosome reorganization events. Finally, some species showed spontaneous rearrangements, possibly as a consequence of an uncommon phenomenon in anuran cytogenetics: the presence of fragile sites or secondary constrictions not associated with NORs. We propose that this rare feature would have played an important role in the evolution of this group of frogs. From the evidence obtained in this and previous studies, we conclude that Lophyohylini presents a complex chromosome evolution., Competing Interests: The authors have declared that no competing interests exist.

Horned Frogs of the family Ceratophryidae are conspicuous anurans represented by three endemic South American genera. Most ceratophryids inhabit semiarid environments, but three species of Ceratophrys occupy tropical or temperate humid areas. Several morphological and behavioral characters of larvae and adults are conserved across the family. Based on examination of specimens and accounts in the literature, the embryonic development of C. ornata, C. cranwelli, and the monotypic genus Chacophrys are described and compared with that of species of Lepidobatrachus. Ceratophryid embryos share a suite of morphological features and heterochronic shifts during development. Most features, such as gill structure, ciliation, early hatching, and precocious differentiation of the gut and hind limbs, are shared by all the species regardless the differences in the habitats that occupy. This is consistent with previous observations of some adult characters, and likely supports the hypothesis of an early diversification of ceratophryids in semiarid environments. Other embryonic features, such as the morphology and ontogeny of the oral disc and digestive tract, are correlated with larval feeding habits and vary within the family. The evolutionary and ecological significance of some conserved characters (e.g., gastrulation pattern, Type-A adhesive glands) and other taxon-specific features (e.g., nasal appendix) remain to be explored in the group., (© 2019 Wiley Periodicals, Inc.)

The genus Scinax currently includes more than 120 species, recovered in two major clades, the S. catharinae and the S. ruber clades. The latter comprises 75 species, most of which remain unassigned to any species groups, while 12 are included in the S. rostratus and S. uruguayus groups. In this paper we present a taxonomic review of the two species currently included in the S. uruguayus group, discussing some putative phenotypic synapomorphies of this group. Although S. pinima and S. uruguayus have been considered as distinct species, this has been based on scant evidence, and several authors doubted of their distinctiveness. Our study of available specimens of S. pinima and S. uruguayus corroborates that both are valid and diagnosable species based on phenotypic evidence. Furthermore, our results show that S. pinima previously known only from its type locality, has a much widespread distribution than previously thought (including the Brazilian states of Paraná, Santa Catarina, and Rio Grande do Sul), which, added to the biological information presented here allows to suggest the removal of this species from the "Data Deficient" IUCN Red List category to "Least Concern". Also, we describe a new species formerly reported as S. aff. pinima and S. uruguayus from NE Argentina and some localities from the Brazilian State of Rio Grande do Sul. All species are diagnosed and characterized using adult and larval morphology, osteology, vocalizations, cytogenetics, and natural history., Competing Interests: The authors have declared that no competing interests exist.

The study of early development in Neotropical Leiuperinae frogs (Anura, Leptodactylidae) has been addressed by several works in recent times. However, a comparative developmental approach under a phylogenetic context was not available. Herein we analyzed the morphological and ontogenetic diversity of embryos belonging to 22 species of the three largest genera in Leiuperinae. We find that in most cases, variations fit with the phylogeny at the inter- and intrageneric levels. Embryo kyphosis and whitish color are synapomorphies for the clade grouping Physalaemus and Engystomops. The presence of a third lower tooth row on the oral disc is plesiomorphic for Leiuperinae, only changing in derived clades. The configurations and developmental trajectories of the lower lip are exceptionally diverse. The developmental sequences optimized on the phylogenetic tree recover an early differentiated first lower tooth row a synapomorphy of Pseudopaludicola and Physalaemus, and an early differentiated second row as synapomorphy of Pleurodema. On the other hand, few features are highly conserved in the subfamily, such as the adhesive glands universally present in a type-C configuration. Our results also suggest that the morphology and ontogeny of embryos is in some cases associated to the environment where they develop. A large body size, poorly developed transient respiratory structures, large yolk provision and delayed development of the digestive tract occur convergently in embryos inhabiting cold, oxygenated environments. Embryos that develop in warmer water bodies in xeric environments show more complex and persistent transient respiratory structures and an early onset of hind limbs development. Our survey highlights that morphology and early development of anurans can be a valuable source of information for phylogenetic studies, and provide fundamental bases to explore and discuss how evolutionary changes can be shaped by environmental conditions., Competing Interests: The authors have declared that no competing interests exist.

In a recent work, Ohler and Dubois (2018) discussed the correct application of Article 23.9 of the Code (Anonymous, 1999; 2012) and illustrated it with some concrete cases in which the authors considered that the Article was misinterpreted. Article 23.9 of the Code allows the "reversal of precedence", that is, that when a senior homonym or synonym has not been used as a valid nomen after 1899 (Article 23.9.1.1) and its junior synonym or homonym has been used as valid for the same taxon in at least 25 works published by at least 10 authors in the immediately preceding 50 years and encompassing a span of not less than 10 years (Article 23.9.1.2), the junior homonym or synonym must be maintained as valid (Article 23.9.1). One of the cases considered by Ohler and Dubois (2018) is the treatment given by Caramaschi and Niemeyer (2010) to the names Hyla prasina Burmeister, 1856 (under the combination Hypsiboas prasinus), and Hyla quoyi Bory de Saint-Vincent, 1828.

The Chaco is one the most neglected and least studied regions of the world. This highly-seasonal semiarid biome is an extensive continuous plain without any geographic barrier, and in spite of its high species diversity, the events and processes responsible have never been assessed. Miocene marine introgressions and Pleistocene glaciations have been mentioned as putative drivers of diversification for some groups of vertebrates in adjacent biomes of southern South America. Here we used multilocus data (one mitochondrial and six nuclear loci) from the three species of the endemic frog genus Lepidobatrachus (Lepidobatrachus asper, Lepidobatrachus laevis, and Lepidobatrachus llanensis) to determine if any of the historical events suggested as drivers of vertebrate diversification in southern South America are related to the diversification of the genus and if the Chaco is indeed a biome without barriers. Using fossil calibration in a coalescent framework we estimated that the genus diversified in the second half of the Miocene, coinciding with marine introgressions. Genetic patterns and historical demography suggest an important role of old archs and cratons as refuges during floods. In one species of the genus, L. llanensis, genetic structure reveals some breaks along the landscape, the main one of which corresponds to an area of the central Chaco that may act as a climatic barrier. Additionally, we found differential effects of the main Chacoan rivers on species of Lepidobatrachus that could be related to the time of persistence of populations in the areas influenced by these rivers., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The hylid tribe Cophomantini is a diverse clade of Neotropical treefrogs composed of the genera Aplastodiscus, Boana, Bokermannohyla, Hyloscirtus, and Myersiohyla. The phylogenetic relationships of Cophomantini have been comprehensively reviewed in the literature, providing a suitable framework for the study of chromosome evolution. Employing different banding techniques, we studied the chromosomes of 25 species of Boana and 3 of Hyloscirtus; thus providing, for the first time, data for Hyloscirtus and for 15 species of Boana. Most species showed karyotypes with 2n = 2x = 24 chromosomes; some species of the B. albopunctata group have 2n = 2x = 22, and H. alytolylax has 2n = 2x = 20. Karyotypes are all bi-armed in most species presented, with the exception of H. larinopygion (FN = 46) and H. alytolylax (FN = 38), with karyotypes that have a single pair of small telocentric chromosomes. In most species of Boana, NORs are observed in a single pair of chromosomes, mostly in the small chromosomes, although in some species of the B. albopunctata, B. pulchella, and B. semilineata groups, this marker occurs on the larger pairs 8, 1, and 7, respectively. In Hyloscirtus, NOR position differs in the three studied species: H. alytolylax (4p), H. palmeri (4q), and H. larinopygion (1p). Heterochromatin is a variable marker that could provide valuable evidence, but it would be necesserary to understand the molecular composition of the C-bands that are observed in different species in order to test its putative homology. In H. alytolylax, a centromeric DAPI+ band was observed on one homologue of chromosome pair 2. The band was present in males but absent in females, providing evidence for an XX/XY sex determining system in this species. We review and discuss the importance of the different chromosome markers (NOR position, C-bands, and DAPI/CMA3 patterns) for their impact on the taxonomy and karyotype evolution in Cophomantini.

The Odontophrynus americanus species group is a complex of diploid and tetraploid species hardly distinguished by morphological characters. It currently consists of three allopatric diploid species (i.e. O. cordobae, O. lavillai, and O. maisuma) and one widely distributed tetraploid species (i.e. O. americanus). We herein describe a new diploid allopatric species from campo rupestre, a typical phytophysiognomy of the Espinhaço Range, Brazil. The new species is distinguishable by the diploid complement of 2n = 2x = 22 chromosomes, small to medium-sized dorsal dark brown blotches with low contrast on a light brown background, light mid-dorsal stripe absent or greatly interrupted in most specimens with yellowish coloration as the background of both head and flanks of the body, advertisement call with dominant frequency of 840-1080 Hz, pulse rate of 90.5-106.7 pulses/s, and small tadpoles (TL = 24.30-35.69 mm).

Although some species groups have been recognized in the leiuperine genus Physalaemus, no phylogenetic analysis has previously been performed. Here, we provide a phylogenetic study based on mitochondrial and nuclear DNA sequences from 41 of the 46 species of Physalaemus. We employed the parsimony criterion using the software TNT and POY and the Bayesian criterion using the software MrBayes. Two major clades were recovered inside the monophyletic Physalaemus: (i) the highly supported Physalaemus signifer Clade, which included P. nattereri and the species previously placed in the P. deimaticus and P. signifer Groups; and (ii) the Physalaemus cuvieri Clade, which included the remaining species of Physalaemus. Five species groups were recognized in the P. cuvieri Clade: the P. biligonigerus Group, the P. cuvieri Group, the P. henselii Group, the P. gracilis Group and the P. olfersii Group. The P. gracilis Species Group was the same as that previously proposed by Nascimento et al. (2005). The P. henselii Group includes P. fernandezae and P. henselii, and was the sister group of a clade that comprised the remaining species of the P. cuvieri Clade. The P. olfersii Group included P. olfersii, P. soaresi, P. maximus, P. feioi and P. lateristriga. The P. biligonigerus Species Group was composed of P. biligonigerus, P. marmoratus, P. santafecinus and P. riograndensis. The P. cuvieri Group inferred here differed from that recognized by Nascimento et al. (2005) only by the inclusion of P. albifrons and the exclusion of P. cicada. The paraphyly of P. cuvieri with respect to P. ephippifer was inferred in all the analyses. Distinct genetic lineages were recognized among individuals currently identified as P. cuvieri and they were congruent with cytogenetic differences reported previously, supporting the hypothesis of occurrence of formally unnamed species., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Dendropsophini is the most species-rich tribe within Hylidae with 234 described species. Although cytogenetic information is sparse, chromosome numbers and morphology have been considered as an important character system for systematic inferences in this group. Using a diversity of standard and molecular techniques, we describe the previously unknown karyotypes of the genera Xenohyla, Scarthyla and Sphaenorhynchus and provide new information on Dendropsophus and Lysapsus. Our results reveal significant karyotype diversity among Dendropsophini, with diploid chromosome numbers ranging from 2n = 22 in S. goinorum, 2n = 24 in Lysapsus, Scinax, Xenohyla, and almost all species of Sphaenorhynchus and Pseudis, 2n = 26 in S. carneus, 2n = 28 in P. cardosoi, to 2n = 30 in all known Dendropsophus species. Although nucleolar organizer regions (NORs) and C-banding patterns show a high degree of variability, NOR positions in 2n = 22, 24 and 28 karyotypes and C-banding patterns in Lysapsus and Pseudis are informative cytological markers. Interstitial telomeric sequences reveal a diploid number reduction from 24 to 22 in Scarthyla by a chromosome fusion event. The diploid number of X. truncata corroborates the character state of 2n = 30 as a synapomorphy of Dendropsophus.

We investigated the NOR distribution in ten populations of Physalaemus cuvieri from different regions of Brazil and Argentina. A high variability in NOR pattern was observed and provided a useful tool in grouping several populations. The specimens from the state of Tocantins, northern Brazil, could easily be distinguished from all the other analyzed populations, since its karyotype presented NORs in the chromosome pairs 1,3,4 and 10 (and sometimes also in chromosome 5), and several pericentromeric C-bands. A NOR-site in chromosome 9 characterized three populations from the northeastern region of Brazil. Interestingly, the P. cuvieri populations located in opposite extremes of the geographic distribution had, as a fixed condition, the presence of NORs in 8q int and llp. Besides interpopulational divergences, intrapopulational variability was observed in the number of NORs, except for populations from the states of Bahia and Minas Gerais, which are boundary states respectively in the northeastern and southeastern regions of Brazil. In relation to NOR size, interindividual variations occurred in all Brazilian and Argentinean populations. Additionally, intraindividual variability in NOR size was detected in specimens from Minas Gerais. The data presented herein revealed substantial geographic polytypic variation in P. cuvieri and indicated that a taxonomic reexamination of this species is necessary.

The article presents a study which examined the external morphology of Telmatobius (T.) platycephalus and T. pinguiculus tadpoles from Argentina. The larvae of Telmatobius platycephalus belong to the benthic ecomorphological guild, body length is less than 40 percent of the total length, and body shape is oval in dorsal view, with maximum body width at posterior portion of head or at abdominal region. Tadpoles of both species have the same labial tooth row formula, while the larvae of Telmatobius pinguiculus belong to the benthic ecomorphological guild.

The article presents a study which examined the meiotic prophase stages of two allopatric tetraploid population groups from southeastern and northwestern Argentina. All normal meiotic stages were observed in cytological preparations and pachytene and zygotene were very frequent insome individuals. A bouquet-like configuration in zygotene with a great delay in the internal pairing was reported, as this meiotic behavior could favour the correct joint of the four chromosomes at their terminal region, and would facilitate the homologous synapsis.