RESUMEN
The Neotropical region is known both for its megadiverse fauna and for the significant deficiency of our knowledge on species limits. The Amazon and Atlantic Forest are the two most diverse and large rainforests in South America, and they harbor many groups of sister species and sister genera. The frog genus Pristimantis is the most speciose genus of terrestrial vertebrates with 546 species, but only three of them occur in the Atlantic forest. Herein, we investigate the diversification history and phylogenetic relationship among the Atlantic Forest Pristimantis lineages in a spatial-temporal framework, using mitochondrial and nuclear genes. Our results reveal a remarkable hidden diversity, with nine highly structure lineages that may correspond to undescribed species, with many cases of sympatry among these divergent lineages. Atlantic forest Pristimantis form a monophyletic group that started to diversify over 40 million years ago. This ancient group shows diversification events that remount the early bursts of the Atlantic Forest diversification history, as well as lineage diversification likely resulting from recent Pleistocene climatic fluctuations. Future work must concentrate in comparing these lineages under an integrative framework including morphology, advertisement calls and other ecology traits to confidently delimit species of Pristimantis in the Atlantic Forest.
Asunto(s)
Anuros/clasificación , Anuros/genética , Bosques , Variación Genética , Animales , Teorema de Bayes , Núcleo Celular/genética , Haplotipos/genética , Filogenia , América del Sur , Especificidad de la Especie , Factores de TiempoRESUMEN
The Neotropical genus Trachycephalus Tschudi currently comprises 14 species distributed in lowlands of Mexico, Central and South America east of the Andes, south until northern Argentina (Frost 2014) and throughout Brazil (IUCN 2014). Seven species of the genus have tadpoles formerly described: T. coriaceus (Peters) (Schiesari & Moreira 1996; Lescure et al. 1996), T. cunauaru Gordo, Toledo, Suárez, Kawashita-Ribeiro, Ávila, Morais & Nunes (Grillitsch 1992 as Phrynohyas resinifictrix according to Gordo et al. 2013), T. jordani (Stejneger & Test) (McDiarmid & Altig 1989-1990), T. mesophaeus (Hensel) (Lutz 1973; Carvalho-e-Silva et al. 2002; Prado et al. 2003), T. nigromaculatus Tschudi (Wogel et al. 2000), T. resinifictrix (Goeldi) (Hero 1990; Schiesari et al. 1996), and T. typhonius (Linnaeus) (Pyburn 1967; Duellman 1970; Schiesari et al. 1996). The oral cavity is described only for T. cunauaru (Grillitsch 1992), T. resinifictrix (Schiesari et al. 1996), and T. typhonius (Schiesari et al. 1996; Fabrezi & Vera 1997).
Asunto(s)
Aletas de Animales/anatomía & histología , Anuros/anatomía & histología , Larva/anatomía & histología , Boca/anatomía & histología , Animales , América Central , América del SurRESUMEN
Scinax melanodactylus is a small treefrog distributed within the Tropical Atlantic morphoclimatic domain (see Ab'Sáber 1977 for South American morphoclimatic domains), from northern Espírito Santo state to Sergipe state in Brazil (Lourenço et al. 2014). The species is usually found inhabiting herbaceous and shrubby xerophytic vegetation (e.g. terrestrial tank-bromeliads) from sandy plains of beach ridges known in Brazil as Restingas (see Rocha et al. 2007 for a Restinga definition), and also the edge of forest areas with temporary ponds and/or permanent lakes and streams near these environments (Bastazini et al. 2007, as Scinax agilis; Lourenço et al. 2014). Scinax melanodactylus is currently placed in the S. catharinae species group (Lourenço et al. 2014), which in turn is included in the S. catharinae clade (sensu Faivovich et al. 2005). The S. catharinae clade is currently comprised of 46 species, 33 placed in the catharinae group and 13 in the perpusillus group (Faivovich et al. 2010, Silva & Alves-da-Silva 2011, Lourenço et al. 2014, Frost 2015). From these, 32 species have tadpoles with external morphology and oral disc formerly described. Here, we describe the external morphology, oral disc and color patterns of the previously unknown tadpole of S. melanodactylus.
Asunto(s)
Larva/anatomía & histología , Larva/clasificación , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Anuros/anatomía & histología , Anuros/clasificación , Anuros/crecimiento & desarrollo , Tamaño Corporal , Brasil , Ecosistema , Femenino , Larva/crecimiento & desarrollo , Masculino , Tamaño de los ÓrganosRESUMEN
From the 86 species allocated in the genus Rhinella, 25 have their tadpoles described and only R. arenarum, R. chrysophora, R. icterica, R. ornata, R. schneideri and R. spinulosa have aspects of the internal oral morphology evidenced. Herein, the internal oral morphology from 12 species of Rhinella distributed between the morphological groups of R. crucifer, R. granulosa, R. marina and R margaritifera is described and compared. The internal oral morphology of Rhinella is little variable in many aspects. Despite the many similarities found between the tadpoles of Rhinella, the study showed that there are characteristics that exhibit interspecific variation that can be used in the taxonomy of the genus. Important features to distinguish species were: number of infrarrostral projections; number and shape of the infralabial papillae; size, arrangement, shape and apex of the lingual papillae; shape of the buccal floor arena papillae; number of projections of the ventral velum; shape of the prenarial ridge; choanae arrangement; number and apex of the postnarial papillae; number and shape of the secondary branches on the lateral ridge papilla; buccal roof arena papillae arrangement.
Asunto(s)
Bufonidae/anatomía & histología , Boca/ultraestructura , Distribución Animal , Animales , Bufonidae/clasificación , Bufonidae/crecimiento & desarrollo , Femenino , Larva/clasificación , Larva/crecimiento & desarrollo , Larva/ultraestructura , Masculino , Microscopía Electrónica de Rastreo , Boca/crecimiento & desarrolloRESUMEN
The genus Phyllodytes comprises 15 species, ten of them having their tadpole external morphology described in the literature. However, there are few descriptive studies on chondrocranium and hyobranchial skeleton. In this work, we describe the chondrocranium and hyobranchial skeleton of Phyllodytes larvae and discuss shared features and interspecific variation. Our findings suggest that the skeletal morphology is mostly conserved in the genus, with common features including a single suprarostral cartilage, short infrarostral cartilages, and overall short trabecular horns. Main intrageneric variations include the arrangement of the ascending process, the presence of larval otic process, and the configuration of the crista parotica. These variations are not correlated with the phylogenetic structure of the genus. Some distinctive aspects of P. praeceptor and P. gyrinaethes are also described in tadpoles of Osteopilus ocellatus, and could be related to oophagous habits in these tadpoles.
Asunto(s)
Anuros , Cráneo , Animales , Cartílago , Larva , FilogeniaRESUMEN
The genus Proceratophrys Miranda-Ribeiro, 1920, frogs from the family Odontophrynidae Lynch, currently contains 41 nominal species with poorly resolved phylogenetic relationships (Frost 2019; Mângia et al. 2018). Molecular data from 15 and 18 Proceratophrys species support the monophyletic hypothesis of the genus (Teixeira-Jr et al. 2012; Dias et al. 2013; respectively) but do not fully resolve the phylogenetic relationship among the species. Currently, there are advertisement call parameters provided for 31 species of Proceratophrys in the literature (Ferreira et al. 2016; Andrade et al. 2018; Mângia et al. 2018; Nascimento et al. 2019). The Proceratophrys advertisement call is composed of pulsed notes, amplitude modulation, short to medium duration calls (0.05-4 s) and only one note in almost all species (see Nascimento et al. 2019 for details). Considering the importance of bioacoustics for taxonomy (Köhler et al. 2017), further descriptions of advertisement calls for the genus could also improve our understanding of the species' relationships.
Asunto(s)
Anuros , Animales , Brasil , Filogenia , Vocalización AnimalAsunto(s)
Anuros/fisiología , Cortejo , Vocalización Animal/fisiología , Animales , Femenino , Masculino , Espectrografía del SonidoRESUMEN
The treefrog Scinax camposseabrai (Bokermann) is endemic to the Brazilian semiarid region and known from the municipalities of Maracás, Igaporã and Curaçá, in the state of Bahia, and from the municipality of Matias Cardoso, northern Minas Gerais state, Brazil (Frost 2019). It was removed from the synonymy of Scinax x-signatus (Spix), recognized as a valid species, and placed in the S. ruber clade (sensu Faivovich et al. 2005) by Caramaschi Cardoso (2006). Taxonomic changes proposed by Duellman et al. (2016) for the genus Scinax were discussed by Lourenço et al. (2016) and Faivovich et al. (2018), and we follow here their suggestion to consider Ololygon and Julianus (erected for the S. uruguayus group) as synonyms of Scinax. This large genus Scinax currently would include 123 species (Frost 2019), many of which have had their larval morphology formerly described. Here, we describe the external morphology of the previously unknown tadpoles of S. camposseabrai.
Asunto(s)
Anuros , Animales , Brasil , LarvaRESUMEN
We performed cytogenetic analyses on specimens from three population samples of Proceratophrys boiei from southeastern and northeastern Brazil. We stained chromosomes of mitotic and meiotic cells with Giemsa, C-banding and Ag-NOR methods. All specimens of P. boiei presented a karyotype with a full chromosome complement of 2n=22, metacentric and submetacentric. We observed the secondary constriction within the short arm of pair 8, which was in the same position of the nucleolus organizer region (NOR). NOR heteromorphism was observed within two specimens from the municipality of Mata de São João (northeastern Bahia State). The C-banding evidenced an unusual heterochromatic pattern in the genome of P. boiei. In the southern most population samples (São Paulo State), we observed large blocks of heterochromatin in the centromeric regions of all chromosomes, whereas the northernmost samples (Bahia State) presented a small amount of constitutive heterochromatin. We suppose that this geographic variation in heterochromatin quantities could be due to heterochromatinization of some chromosome regions in the genome of the São Paulo samples. Furthermore, females from São Paulo presented, within chromosome pair 1 from C-banded karyotypes, one homologous chromosome almost heterochromatic, whereas males had heterochromatin restricted to the centromeric region. This unusual heterochromatic arrangement led us to assume that P. boiei owns a ZZ/ZW type of sexual determination system. This finding is very important, as this is the first record of ZZ/ZW sex chromosomes within Cycloramphidae. We believe that the cytogenetic differences found between southeastern and northeastern Brazilian population samples of P. boiei strongly supports the existence of a species complex under the name P. boiei, and the requirement of taxonomic and systematic reviews by morphological, bioacoustical, molecular, and cytogenetic data could define this taxonomic issue in the future.
Asunto(s)
Anfibios/genética , Bandeo Cromosómico , Cromosomas Sexuales/genética , Animales , Brasil , Clasificación , Femenino , Heterocromatina , Masculino , Polimorfismo GenéticoRESUMEN
We aim to evaluate the genetic structure of an Atlantic Forest amphibian species, Scinax eurydice, testing the congruence among patterns identified and proposed by the literature for Pleistocene refugia, microrefugia, and geographic barriers to gene flow such as major rivers. Furthermore, we aim to evaluate predictions of such barriers and refugia on the genetic structure of the species, such as presence/absence of dispersal, timing since separation, and population expansions/contractions. We sequenced mitochondrial and nuclear genetic markers on 94 tissue samples from 41 localities. We inferred a gene tree and estimated genetic distances using mtDNA sequences. We then ran population clustering and assignment methods, AMOVA, and estimated migration rates among populations identified through mtDNA and nDNA analyses. We used a dated species tree, skyline plots, and summary statistics to evaluate concordance between population's distributions and geographic barriers and Pleistocene refugia. Scinax eurydice showed high mtDNA divergences and four clearly distinct mtDNA lineages. Species tree and population assignment tests supported the existence of two major clades corresponding to northeastern and southeastern Atlantic Forest in Brazil, each one composed of two other clades. Lineage splitting events occurred from late Pliocene to Pleistocene. We identified demographic expansions in two clades, and inexistent to low levels of migrations among different populations. Genetic patterns and demographic data support the existence of two northern Refuge and corroborate microrefugia south of the Doce/Jequitinhonha Rivers biogeographic divide. The results agree with a scenario of recent demographic expansion of lowland taxa. Scinax eurydice comprises a species complex, harboring undescribed taxa consistent with Pleistocene refugia. Two rivers lie at the boundaries among populations and endorse their role as secondary barriers to gene flow.
Asunto(s)
Anuros/clasificación , Biodiversidad , Bosques , Filogenia , Migración Animal , Animales , Anuros/genética , Brasil , ADN Mitocondrial/genética , Genética de Población , GeografíaRESUMEN
Abstract: Studying feeding habits is crucial to understand complex predator-prey interactions. Even though anurans play a fundamental role in the control of arthropods populations, the diet of several Neotropical species is poorly known. We describe the frequency and occurrence of prey items and their dry mass in stomach contents of the Robber Frog Pristimantis paulodutrai in the north east of the state of Bahia, Brazil. Based on the stomach contents of 30 individuals, Araneae, Isopoda, and Formicidae were found to be the most important food items. The generalist diet of this frog, which seems to be phylogenetically conserved among Pristimantis, is likely to be linked to its ecological dominance in the habitats surveyed. Our study corroborates the high trophic relevance of Robber Frogs in tropical forests as generalist predators.
Resumo: Estudar hábitos alimentares é crucial para entender as complexas interações predador-presa. Embora os anuros tenham papel fundamental no controle das populações de artrópodes, a dieta de várias espécies neotropicais é pouco conhecida. Descrevemos a frequência e a ocorrência de presas e sua massa seca no conteúdo estomacal da rã Pristimantis paulodutrai, no nordeste do estado da Bahia, Brasil. Com base no conteúdo estomacal de 30 indivíduos, Araneae, Isopoda e Formicidae foram os itens alimentares mais importantes. A dieta generalista desta rã, a qual parece ser conservada filogeneticamente entre os Pristimantis, provavelmente está ligada à sua dominância ecológica nos habitats pesquisados. Nosso estudo corrobora a alta relevância trófica dos Robber Frogs em florestas tropicais como predadores generalistas.
RESUMEN
The east coast of Brazil comprises an extensive area inserted in the Tropical Atlantic Domain and is represented by sandy plains of beach ridges commonly known as Restingas. The coastal environments are unique and house a rich amphibian fauna, the geographical distribution patterns of which are incipient. Biogeographical studies can explain the current distributional patterns and provide the identification of natural biogeographical units. These areas are important in elucidating the evolutionary history of the taxa and the areas where they occur. The aim of this study was to seek natural biogeographical units in the Brazilian sandy plains of beach ridges by means of distribution data of amphibians and to test the main predictions of the vicariance model to explain the patterns found. We revised and georeferenced data on the geographical distribution of 63 anuran species. We performed a search for latitudinal distribution patterns along the sandy coastal plains of Brazil using the non-metric multidimensional scaling method (NMDS) and the biotic element analysis to identify natural biogeographical units. The results showed a monotonic variation in anuran species composition along the latitudinal gradient with a break in the clinal pattern from 23°S to 25°S latitude (states of Rio de Janeiro to São Paulo). The major predictions of the vicariance model were corroborated by the detection of four biotic elements with significantly clustered distribution and by the presence of congeneric species distributed in distinct biotic elements. The results support the hypothesis that vicariance could be one of the factors responsible for the distribution patterns of the anuran communities along the sandy coastal plains of eastern Brazil. The results of the clusters are also congruent with the predictions of paleoclimatic models made for the Last Glacial Maximum of the Pleistocene, such as the presence of historical forest refugia and biogeographical patterns already detected for amphibians in the Atlantic Rainforest.
Asunto(s)
Anuros/clasificación , Ecosistema , Animales , Biodiversidad , Brasil , Geografía , Dinámica PoblacionalRESUMEN
Dendropsophus branneri is a small treefrog largely distributed throughout the Tropical Atlantic and Caatinga morphoclimatic domains (see Ab'Sáber 1977 for morphoclimatic domains), from northeastern to southeastern Brazil [Lutz 1973, Frost 2014; see Zina et al. 2014 for taxonomic comments on D. minusculus (Rivero, 1971) and D. branneri]. This species is currently placed in the D. microcephalus species group according to Bastos & Pombal (1996) and Faivovich et al. (2005). The D. microcephalus group comprises 36 species (Frost 2014), 14 of which have known tadpoles. Here, we describe the external morphology and color patterns of the previously unknown tadpole of D. branneri.
Asunto(s)
Anuros/anatomía & histología , Anuros/crecimiento & desarrollo , Larva/anatomía & histología , Animales , Anuros/clasificación , BrasilRESUMEN
The treefrog genus Dendropsophus Fitzinger comprises 95 species, with geographic distribution from northern Argentina and Uruguay north through tropical South and Central America to tropical southern Mexico (Frost 2014). Dendropsophus studerae was included in the D. microcephalus clade by Faivovich et al. (2005), which currently consists of 39 species (Frost 2014). The species that most resembles D. studerae is D. bipunctatus (Spix), as already stated in the original description of the former (Carvalho-e-Silva et al. 2003). Thus far, Dendropsophus studerae was only known from its type locality, in the municipality of Quebrangulo (09º19'08"S, 36º28'16"W), State of Alagoas, northeastern Brazil. The original description of the species also included data on its eggs, tadpole (oral disc and external morphology) and some natural history information of adults and larvae, but its advertisement call remains undescribed.
Asunto(s)
Anuros/clasificación , Anuros/fisiología , Vocalización Animal , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Anuros/anatomía & histología , Anuros/crecimiento & desarrollo , Tamaño Corporal , Ecosistema , Femenino , Masculino , Tamaño de los ÓrganosRESUMEN
Abstract The Conde municipality is located in the northern coast of the state of Bahia (NC), northeastern Brazil, and is part of the Atlantic Tropical domain. The anuran fauna of the northern portion of the NC is still poorly known if compared to the southern portion. The Restinga is one of the predominant environments of the coastal plains of the NC and it is characterized essentially by presenting sandy soil covered by herbaceous and shrubby vegetation. The objective of this study was to determine the anuran species composition and diversity for the Restinga of the Conde municipality. Sampling was carried out at night by active search over four periods of five consecutive days each, two over the 'main rainy season' and two in a 'lesser rainy season', using 14 sample units (SUs) and five extra sample plots (EPs). We calculated dominance and species diversity using the Berger-Parker and Shannon-Wiener H' indices, respectively. We used accumulation curves and the Jackknife 1 estimator to estimate anuran species richness, considering only the data obtained from the SUs. We recorded 713 anuran specimens distributed within 33 species, 13 genera and five families (Bufonidae, Craugastoridae, Hylidae, Leptodactylidae and Microhylidae). The Hylidae and Leptodactylidae families had the highest species richness. Considering only the SUs (Jackknife 1 estimator in brackets), we recorded 28 species in the study area (33.9 ± 2.3), 13 in Shrubby Vegetation Zones - SVZ (20.8 ± 2.9) and 25 in Freshwater Wetland Zones - FWZ (28.9 ± 1.9). The abundance and species diversity of the FWZ (n = 638 specimens; H'= 2.4) were higher than those recorded for the SVZ (n = 52 specimens; H' = 1.9). The SVZ and FWZ showed distinct dominant species, wherein Pristimantis paulodutrai was the dominant species in SVZ and Scinax fuscomarginatus in FWZ. The Restinga of the Conde municipality stands out as the one with the highest anuran species richness already recorded considering only SVZ and FWZ. Moreover, its anuran species composition represented 55% of the anuran species known for the NC and included taxa common to three different morphoclimatic domains (Tropical Atlantic, Cerrado and Caatinga).
Resumo O município de Conde situa-se no litoral norte do estado da Bahia (LN), nordeste do Brasil, e está inserido no domínio Tropical Atlântico. A fauna de anuros da porção setentrional do LN ainda é pouco conhecida se comparada à porção sul. A Restinga é um dos ambientes predominantes das planícies costeiras do LN, sendo caracterizada essencialmente por apresentar solo arenoso e vegetação herbácea e arbustiva. O objetivo deste estudo foi determinar a composição e a diversidade de espécies de anuros da Restinga do município de Conde. A amostragem foi realizada por procura ativa noturna, durante quatro períodos de cinco dias consecutivos cada, dois na estação 'mais chuvosa' e dois em estação 'menos chuvosa', utilizando-se 14 unidades amostrais (UAs) e cinco pontos amostrais extras (PEs). Calculamos a dominância e a diversidade de espécies utilizando os índices de Berger-Parker e de Shannon-Wiener-H'. Utilizamos curvas de acumulação de espécies e o estimador Jackknife 1 para estimar a riqueza de espécies de anuros, considerando-se somente os dados obtidos nas UAs. Registramos 713 espécimes de anuros distribuídos em 33 espécies, 13 gêneros e cinco famílias (Bufonidae, Craugastoridae, Hylidae, Leptodactylidae e Microhylidae). As famílias Hylidae e Leptodactylidae apresentaram as maiores riquezas de espécies. Considerando-se somente UAs (estimador Jackknife 1 entre parêntesis) foram registradas 28 espécies na área de estudo (33,9 ± 2,3), 13 nas zonas de moitas (20,8 ± 2,9) e 25 nas zonas úmidas (28,9 ± 1,9). A abundância e a diversidade de espécies para as zonas úmidas (n = 638 espécimes; H' = 2,4) foram superiores às registradas para as zonas de moitas (n = 52 espécimes; H' = 1,9). As zonas de moitas e úmidas exibiram espécies dominantes distintas, sendo Pristimantis paulodutrai a espécie dominante para as zonas de moitas e Scinax fuscomarginatus para as zonas úmidas. A Restinga do município de Conde desponta como aquela de maior riqueza de espécies de anuros já registrada considerando-se somente zonas de moitas e zonas úmidas. Além disso, sua composição de espécies de anuros representou 55% do total de espécies de anuros conhecidas para o LN e incluiu táxons comuns a três diferentes domínios morfoclimáticos (Tropical Atlântico, Cerrado e Caatinga).
RESUMEN
The Middle Jaguaribe River region is a poorly sampled area in the Caatingas domain, located in the eastern Ceará State, northeastern Brazil. The Brazilian government agencies considered this region as a priority area for conservation and inventories. In order to fill this biodiversity knowledge gap, we conducted a ten-day rapid inventory of the anuran fauna from April 11 to 20, 2014, surveying different physiognomies of the region. We recorded 19 anuran species belonging to five families: Bufonidae (2), Hylidae (5), Leptodactylidae (9), Microhylidae (2) and Odontophrynidae (1). Most inventories of Caatinga amphibians published to date have been conducted inside protected areas and/or of high altitude (mesic areas known as "brejos de altitude"). The list we present herein contributes to the knowledge of lowland Caatinga sites outside protected areas. We discuss our results in light of taxonomic and geographic features of the anurans sampled.
A Região do Médio Rio Jaguaribe é uma área pobremente amostrada no domínio das Caatingas, localizada no leste do Estado do Ceará, Nordeste do Brasil. O Ministério do Meio Ambiente considera esta região como uma área prioritária para conservação e realização de inventários. Com o objetivo de preencher esta lacuna do conhecimento sobre a biodiversidade, nós conduzimos um inventário rápido da anurofauna de dez dias de 11 a 20 de Abril de 2014, amostrando diferentes fisionomias da região. Nós registramos 19 espécies de anfíbios anuros pertencentes a cinco famílias: Bufonidae (2), Hylidae (5), Leptodactylidae (9), Microhylidae (2) e Odontophrynidae (1). A maioria dos inventários de anfíbios na Caatinga publicados até o presente momento foram conduzidos em áreas de proteção e/ou de áreas de altitude (áreas mésicas conhecidas como “Brejos de Altitude”). A presente lista contribui para o conhecimento de áreas de baixada da Caatinga fora das áreas protegidas. Nós discutimos os resultados è luz de características taxonômicas e biogeográficas dos anuros amostrados.
RESUMEN
Amphibians experiencing evapotranspirative water loss may suffer dehydration. Another difficulty is their limited tolerance to brackish water. This study aimed to investigate the effect of water salinity on behavior (activity and water conservation posture) in Leptodactylus macrosternum, in normally hydrated animals with urine in their bladder, in normally hydrated animals without urine in their bladder and in dehydrated ones with urine removed from their bladder. Experiments were filmed, behaviors were registered, and a Behavioral Dehydration Protection Index (BDPI) was calculated, using a weighted average of the postures. A GLM and Kruskall Wallis test was performed with Dunn's multiple comparisons test to evaluate the effects of osmotic gradient stress on BDPI. It was found that emptied bladder and aerial dehydration did not influence BDPI (p = 0.832 and p = 0.142, respectively), contrary to what is seen in the literature. The different osmotic media had a significant effect on BDPI (p = 0.0003).
Anfíbios que experimentam perda de água podem sofrer desidratação. Outra dificuldade é a tolerância limitada à água salobra. Este trabalho teve como objetivo estudar o efeito da salinidade da água no comportamento (atividade e postura de conservação de água) de L. macrosternum, normalmente hidratados com urina armazenada na bexiga, normalmente hidratados com urina removida da bexiga e nos desidratados com urina removida da bexiga. Os experimentos foram filmados e foi calculado o índice de proteção comportamental da desidratação (BDPI) usando média ponderada. Realizamos modelo linear generalizado e teste Kruskall-Wallis com comparação múltipla de Dunn, para analisar o efeito dos gradientes de estresse osmótico sobre o BDPI. Observamos que a bexiga esvaziada e a desidratação exercida pelo ar não influenciam o aumento do BDPI (p = 0.832 e p = 0.142, respectivamente) sendo contrário ao visto em literatura. Os diferentes meios osmóticos tiveram efeito sobre o BDPI (p = 0.0003).