Papers by Claudio Borteiro Machado
Current Herpetology, Aug 1, 2018
Observations on stereotyped defensive behaviours are presented for 7 frog species of the Neotropi... more Observations on stereotyped defensive behaviours are presented for 7 frog species of the Neotropical genus Odontophrynus from Argentina and Uruguay. Seven stereotyped postures were observed, among which the most common observed were puffing up the body, contracting, and crouching down. Newly reported behaviours include tongue protrusion, eye protection, and some combinations of postures. We provide an account of defensive behaviours already described in Odontophrynus and discuss the correspondence between the terminology used by previous authors and recently proposed classifications. In addition, we highlight defensive mechanisms associated with the body raising posture in Neotropical anurans, which may include intimidating predators, body shape disruption, warning signaling, and exposure of skin macroglands.
New York, NY : American Museum of Natural History. eBooks, Mar 31, 2021
Studies on Neotropical Fauna and Environment, Apr 1, 2009
Revista de Biologia Neotropical, Feb 25, 2023
Caiman latirostris is a Neotropical crocodilian for which there is scarce natural history informa... more Caiman latirostris is a Neotropical crocodilian for which there is scarce natural history information in regard to other species, as also about survey methods used by field researchers. In this work we report the capture methodology implemented during population monitoring in northern Uruguay and some observations about defensive and feeding behaviours. We found the use of a metallic clamp as very useful for capturing juveniles and subadult individuals (< 120 cm total length) in vegetated habitats, while a wire snare was used for adults. Regardless locomotor escape, we provide a reappraisal of defensive behaviours in the presence of humans, with comments on tonic immobility. In addition, we suggest an apparent case of carcass consumption (scavenging) for the species, a presumably common behaviour but sometimes hard to observe in wild crocodilians.
Supplemental Material for 'Evolution in the genus Rhinella : a total evidence phylogenetic an... more Supplemental Material for 'Evolution in the genus Rhinella : a total evidence phylogenetic analysis of neotropical true toads (Anura: Bufonidae). (Bulletin of the American Museum of Natural History, no. 447)
Bulletin of the American Museum of Natural History, Mar 31, 2021
True toads of the genus Rhinella are among the most common and diverse group of Neotropical anura... more True toads of the genus Rhinella are among the most common and diverse group of Neotropical anurans. These toads are widely distributed throughout South America, inhabiting a great diversity of environments and ecoregions. Currently, however, the genus is defined solely on the basis of molecular characters, and it lacks a proper diagnosis. Although some phenetic species groups have traditionally been recognized within Rhinella, the monophyly of some of them have been rejected in previous phylogenetic analyses, and many species remain unassigned to these poorly defined groups. Additionally, the identity and taxonomy of several species are problematic and hinder the specific recognition and description of undescribed taxa. In this work, we first perform phylogenetic analyses of separate mitochondrial and nuclear datasets to test the possible occurrence of hybridization and/or genetic introgression in the genus. The comparative analysis of both datasets revealed unidirectional mitochondrial introgressions of an unknown parental species into R. horribilis ("ghost introgression") and of R. dorbignyi into R. bernardoi; therefore, the mitochondrial and nuclear datasets of these species were considered separately in subsequent analyses. We performed total-evidence phylogenetic analyses that included revised molecular (four mitochondrial and five nuclear genes) and phenotypic (90 characters) datasets for 83 nominal species of Rhinella, plus several undescribed and problematic species and multiple outgroups. Results demonstrate that Rhinella was nonmonophyletic due to the position of R. ceratophrys, which was recovered as the sister taxon of Rhaebo nasicus with strong support. Among our outgroups, the strongly supported Anaxyrus + Incilius is the sister clade of all other species of Rhinella. Once R. ceratophrys is excluded, the genus Rhinella is monophyletic, well supported, and composed of two major clades. One of these is moderately supported and includes species of the former R. spinulosa Group (including R. gallardoi); the monophyletic R. granulosa, R. crucifer, and R. marina Groups; and a clade composed of the mitochondrial sequences of R. horribilis. The other major clade is strongly supported and composed of all the species from the non-monophyletic R. veraguensis and R. margaritifera Groups, the former R. acrolopha Group, and R. sternosignata. Consistent with these results, we define eight species groups of Rhinella that are mostly diagnosed by phenotypic synapomorphies in addition to a combination of morphological character states. Rhinella sternosignata is the only species that remains unassigned to any group. We also synonymize nine species, treat three former subspecies as full species, and suggest that 15 lineages represent putative undescribed species. Lastly, we discuss the apparently frequent occurrence of hybridization, deep mitochondrial divergence, and "ghost introgression"; the incomplete phenotypic evidence (including putative character systems that could be used for future phylogenetic analyses); and the validity of the known fossil record of Rhinella as a source of calibration points for divergence dating analyses. R. margaritifera Group (1) "old world" bufonids R. acrolopha Group (1) other bufonids Anaxyrus Incilius "R. spinulosa Group" (1) R. granulosa Group (1) R. marina Group (3) R. veraguensis Group (1) "R. spinulosa Group" (1) "old world" bufonids A Pauly et al. (2004) B Frost et al. (2006) C Pramuk (2006) R. margaritifera Group (8) R. marina Group (6) Anaxyrus Incilius R. spinulosa Group (6) R. acrolopha Group (1) + "R. veraguensis Group" (2) "R. veraguensis Group" (3) R. crucifer Group (1) R. granulosa Group (3) "old world" bufonids R. margaritifera Group (8) R. marina Group (6) Anaxyrus Incilius R. spinulosa Group (?) R. acrolopha Group (1) + "R. veraguensis Group" (3) "R. veraguensis Group" (3) R. crucifer Group (1) R. granulosa Group (3) R. spinulosa Group (?) R. margaritifera Group (8) R. marina Group (6) Anaxyrus Incilius "old word" bufonids R. spinulosa Group (2) R. acrolopha Group (1) + "R. veraguensis Group" (3) "R. veraguensis Group" (3) R. crucifer Group (1) R. granulosa Group (4) R. spinulosa Group (5) D Chaparro et al. (2007) E van Bocxlaer et al. (2010) F Pyron and Wiens (2011) "old world" bufonids R. crucifer Group (1) + R. marina Group (6) R. margaritifera Group (4) Anaxyrus Incilius R. spinulosa Group (4) R. acrolopha Group (3) "R. veraguensis Group" (3) "R. veraguensis Group" (2) R. granulosa Group (2) R. spinulosa Group (2) H Pereyra et al. (2016a) "old world" bufonids "R. marina Group" (2) "R. marina Group" (1) R. crucifer Group (2) R. margaritifera Group (4) Anaxyrus Incilius R. veraguensis Group (1) R. sternosignata R. granulosa Group (12) R. spinulosa Group (2) I Jetz and Pyron (2018) G Pyron (2014) "old world" bufonids R. crucifer Group (1) R. marina Group (6) R. margaritifera Group (4) Anaxyrus Incilius R. spinulosa Group (4) R. acrolopha Group (3) "R. veraguensis Group" (3) "R. veraguensis Group" (2) R. granulosa Group (2) R. spinulosa Group (2) R. acrolopha Group (3) + "R. veraguensis Group" (4) R. crucifer Group (6) + R. marina Group (10) R. margaritifera Group (8) R. spinulosa Group (2) "R. veraguensis Group" (1) R. granulosa Group (6) R. spinulosa Group (4)
Herpetological Monographs, Nov 18, 2022
Cuadernos de Herpetología, Sep 24, 2018
We communicate the finding of a subcutaneous neoplasia in a female specimen of the toad Melanophr... more We communicate the finding of a subcutaneous neoplasia in a female specimen of the toad Melanophryniscus montevidensis (Bufonidae) from Uruguay. The lesion extended from the cephalic to the abdominal region, and both gross and microscopic features were typical of lipomas. This is to our knowledge the fourth case reported in amphibians.
Phyllomedusa: Journal of Herpetology, Dec 1, 2006
Geographic distribution and conservation status of Caiman latirostris (Crocodylia, Alligatoridae)... more Geographic distribution and conservation status of Caiman latirostris (Crocodylia, Alligatoridae) in Uruguay. Populations of Caiman latirostris are known to occur in Uruguay but their geographic distribution remains uncertain. This work presents an update of the species distribution and conservation status in Uruguay. Surveys conducted by the authors confirmed the presence of this species in the previously known distribution range of northwestern Uruguay, where it seems to be widespread and relatively abundant in contrast to earlier reports. We report new localities for C. latirostris, most relevant being those of the Cebollatí and Tacuarí Rivers, and the Pelotas, India Muerta and San Miguel stream basins, which significantly expand its distribution through important wetlands in the eastern part of the country. The overall distribution is coincident with different landscape types, where lagoons, artificial impoundments, livestock waterholes, rivers, streams, creeks and marshes are inhabited by caiman. Illegal non-commercial hunting was detected all over the country.
Revista de Biologia Neotropical, Feb 25, 2023
We studied in this work the skin healing process in the terrestrial toad Melanophryniscus montevi... more We studied in this work the skin healing process in the terrestrial toad Melanophryniscus montevidensis. Wild specimens were acclimated in the laboratory, and an experimental skin wound of 1.5 mm diameter was made in the dorsum region under clove oil anesthesia, leaving the dermis exposed. Monitoring of the healing process by conventional histology was made up to 129 days. The epidermal protection of the wound was recovered after two days, and apparently, a complete recovery of dermal glandular structures was evident after 37 days. This feature includes the serous glands that play a relevant role in the defensive strategy of this species. No complications were recorded from the anesthetic procedure, not previously assessed in Melanophryniscus.
PeerJ, Oct 11, 2019
A new species of Leptodactylus frog (Anura: Leptodactylidae) from the South American Gran Chaco, ... more A new species of Leptodactylus frog (Anura: Leptodactylidae) from the South American Gran Chaco, morphologically similar and previously confused with the widespread Leptodactylus mystacinus, is described through the use of multiple sources of evidence (molecular, external morphology, coloration, osteology, bioacoustics, and behavior). The phylogenetic analysis with partial sequences of mitochondrial rDNA genes (12S and 16S) recovered the new species within the L. fuscus group, being highly divergent (>3% genetic distance in 16S). The new species was recovered as sister taxa of L. mystacinus, from which it is distinguished by tympanum coloration, cephalic index, dorsum and legs coloration, and some osteological differences in nasals and prevomers. This new frog is characterized by a moderate body size (SVL 46.80-66.21 mm), distinctive color pattern (reddish dorsal surfaces of body with noticeable black stripes in the dorsolateral folds), a circular and dark tympanum with dark tympanic annuli, and behavior of males that call on top of fallen logs and tree branches close to the ground.
South American Journal of Herpetology
Environmental Conservation, Oct 28, 2022
Anais da Academia Brasileira de Ciências
Intending to increase the knowledge about cytogenetics of Physalaemus and the sparsely studied P.... more 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.
Veterinaria (Montevideo), Jul 1, 2005
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Papers by Claudio Borteiro Machado