First report of Gogia (Eocrinoidea, Echinodermata) from the Early-Middle Cambrian of Sonora (Mexico), with biostratigraphical and palaeoecological comments.

10 pagesInternational audienceThe blastozoan echinoderm genus Gogia is reported for the first time in the Early and the Middle Cambrian of Mexico. Reports in different members of the section of San José de Gracia (Sonora State, northwestern Mexico) extend the palaeogeographical range of the genus to the South Laurentia, and the stratigraphic range of Gogia granulosa to the whole first half of middle Middle Cambrian. Isolated plates occur in rocks deposited in detrital inner platform and complete specimens, in carbonate outer platform, confirming their ability to live in diverse environments. Their presence in these different environments through the Early-Middle Cambrian on Laurentia agrees with the onshore-offshore expansion of echinoderms during Cambrian

Gland composition in sexually dimorphic skin structures of two species of Hylid frogs: Plectrohyla guatemalensis and Ptychohyla hypomykter

Secondary sexual characters form a diverse group of traits widely spread in amphibians. Within anurans, the Hylini tribe represents an interesting group to examine the evolution of this type of characters because it has different skin structure modifications, including ventrolateral glands, nuptial pads, and unique swollen upper lips. We analysed the skin gland composition in the upper lip of Plectrohyla guatemalensis and the ventrolateral gland of Ptychohyla hypomykter (Hylidae: Hylinae: Hylini). Each of these species is characterized by a different type of sexually dimorphic skin gland; specialized mucous glands (SMGs) in Pl. guatemalensis and specialized serous glands (SSGs) in Pt. hypomykter. The SMGs conform to the general type of sexually dimorphic skin glands in amphibians, whereas SSGs are very rare. Because SMGs are likely involved in the production of sexual pheromones, their distinctive location and their co-occurrence with other secondary sexual characters like long and pointed maxillary and premaxillary teeth in Pl. guatemalensis suggests that the system used for their delivery may be a distinguishing behavioral feature in this species. The presence of both types of glands in Pt. hypomykter (SMGs in nuptial pads, and SSGs in ventrolateral glands) suggests a different or, at least, a complementary role of these two types of glands during reproduction.Fil: Luna, María Celeste. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Vásquez Almazán, Carlos Roberto. Universidad de San Carlos; GuatemalaFil: Faivovich, Julián. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Brunetti, Andrés Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Posadas; Argentin

Biogeography and evolution of Central American cloud forest salamanders (Caudata: Plethodontidae: Cryptotriton), with the description of a new species

The cloud forests of Mesoamerica are notable for their high endemism, and plethodontid salamanders provide a striking example of divergence and microendemism across cloud forest blocks at a regional level. Salamanders that make use of arboreal bromeliad microhabitats in the cloud forest appear to be especially prone to divergence driven by natural habitat fragmentation, and are expected to show high endemism at small spatial scales. We use a multilocus dataset to investigate the biogeographic history and relationships among species of a small genus of salamander, Cryptotriton, restricted to the cloud forests of Nuclear Central America. We use a morphological data set along with a coalescent species delimitation method to reveal the presence of at least one undescribed species from an isolated cloud forest in eastern Guatemala. Biogeographic analyses show that Cryptotriton has a different biogeographic history than another clade of cloud forest-restricted salamanders in the same region, perhaps indicating that each genus restricted the spatial expansion and diversification of the other through preemptive occupancy. Our results suggest that isolation across relatively short geographic distances has led to range fragmentation and deep divergence between species. Exploration of remaining patches of cloud forest likely will continue to reveal undetected diversity

Figure 3 in Biogeography and evolution of Central American cloud forest salamanders (Caudata: Plethodontidae: Cryptotriton), with the description of a new species

Figure 3. Species tree estimate from *BEAST analysis of nuclear loci. Numbers indicate posterior probability of clades.Published as part of <i>Rovito, Sean M., Vásquez-Almazán, Carlos R., Papenfuss, Theodore J., Parra-Olea, Gabriela & Wake, David B., 2015, Biogeography and evolution of Central American cloud forest salamanders (Caudata: Plethodontidae: Cryptotriton), with the description of a new species, pp. 150-166 in Zoological Journal of the Linnean Society 175 (1)</i> on page 157, DOI: 10.1111/zoj.12268, <a href="http://zenodo.org/record/10107821">http://zenodo.org/record/10107821</a&gt

Figure 5 in Biogeography and evolution of Central American cloud forest salamanders (Caudata: Plethodontidae: Cryptotriton), with the description of a new species

Figure 5. Results of LAGRANGE analysis of geographic range evolution of Cryptotriton. Results for other genera are not shown. Pies at nodes are colored by the relative probability of each geographic range combination, and squares at tips show the areas currently occupied by each species. Each node has a pie representing the range of the ancestor prior to the speciation event and two pies representing the range of each daughter species immediately after the speciation event.Published as part of <i>Rovito, Sean M., Vásquez-Almazán, Carlos R., Papenfuss, Theodore J., Parra-Olea, Gabriela & Wake, David B., 2015, Biogeography and evolution of Central American cloud forest salamanders (Caudata: Plethodontidae: Cryptotriton), with the description of a new species, pp. 150-166 in Zoological Journal of the Linnean Society 175 (1)</i> on page 159, DOI: 10.1111/zoj.12268, <a href="http://zenodo.org/record/10107821">http://zenodo.org/record/10107821</a&gt

Dramatic declines in neotropical salamander populations are an important part of the global amphibian crisis

We document major declines of many species of salamanders at several sites in Central America and Mexico, with emphasis on the San Marcos region of Guatemala, one of the best studied and most diverse salamander communities in the Neotropics. Profound declines of several formerly abundant species, including 2 apparent extinctions, are revealed. Terrestrial microhabitat specialists at mid- to high elevations have declined more than microhabitat generalists. These terrestrial microhabitat specialists have largely disappeared from multiple sites in western Guatemala, including in well-protected areas, suggesting that the phenomenon cannot be explained solely by localized habitat destruction. Major declines in southern Mexican plethodontid salamanders occurred in the late 1970s to early 1980s, concurrent with or preceding many reported frog declines. The species in decline comprise several major evolutionary lineages of tropical salamanders, underscoring that significant portions of the phylogenetic diversity of Neotropical salamanders are at risk. Our results highlight the urgent need to document and understand Neotropical salamander declines as part of the larger effort to conserve global amphibian diversity

Deep divergences and extensive phylogeographic structure in a clade of lowland tropical salamanders

<p>Abstract</p> <p>Background</p> <p>The complex geological history of Mesoamerica provides the opportunity to study the impact of multiple biogeographic barriers on population differentiation. We examine phylogeographic patterns in a clade of lowland salamanders (<it>Bolitoglossa</it> subgenus <it>Nanotriton</it>) using two mitochondrial genes and one nuclear gene. We use several phylogeographic analyses to infer the history of this clade and test hypotheses regarding the geographic origin of species and location of genetic breaks within species. We compare our results to those for other taxa to determine if historical events impacted different species in a similar manner.</p> <p>Results</p> <p>Deep genetic divergence between species indicates that they are relatively old, and two of the three widespread species show strong phylogeographic structure. Comparison of mtDNA and nuclear gene trees shows no evidence of hybridization or introgression between species. Isolated populations of <it>Bolitoglossa rufescens</it> from Los Tuxtlas region constitute a separate lineage based on molecular data and morphology, and divergence between Los Tuxtlas and other areas appears to predate the arrival of <it>B. rufescens</it> in other areas west of the Isthmus of Tehuantepec. The Isthmus appears responsible for Pliocene vicariance within <it>B. rufescens</it>, as has been shown for other taxa. The Motagua-Polochic fault system does not appear to have caused population vicariance, unlike in other systems.</p> <p>Conclusions</p> <p>Species of <it>Nanotriton</it> have responded to some major geological events in the same manner as other taxa, particularly in the case of the Isthmus of Tehuantepec. The deep divergence of the Los Tuxtlas populations of <it>B. rufescens</it> from other populations highlights the contribution of this volcanic system to patterns of regional endemism, and morphological differences observed in the Los Tuxtlas populations suggests that they may represent an undescribed species of <it>Bolitoglossa</it>. The absence of phylogeographic structure in <it>B. nympha</it>, in contrast to the other widespread species in the subgenus, may be due to historical forest contraction and more recent range expansion in the region. Phylogeographic data provide substantial insight into the evolutionary history of these morphologically similar species of salamanders, and contribute to our understanding of factors that have generated the high biodiversity of Mesoamerica.</p

Sexual dimorphism, phenotypic integration, and the evolution of head structure in casque-headed lizards

Sexes can differ in features associated with differential reproduction, which can be used during courtship or aggressive encounters. Some traits tend to evolve independently between sexes and emerge as sexually dimorphic within the organismal phenotype. We characterize such a relationship by estimating the phenotypic integration of the head morphology and modularity of the crest in the casque-headed lizards (Corytophanidae). In this clade, some species show extreme sexual dimorphism (e.g., head crests in the genus Basiliscus) while in others, both sexes are monomorphic. To characterize these patterns, we define phenotypic integration at the interspecific level as a pattern or network of traits evidenced by phylogenetically adjusted correlations that persist among species. At this level, modularity is an increased connectedness (e.g., higher correlation) among sections of these networks that persist in a lineage during the evolution of complex phenotypes. To test both concepts, we used phylogenetic geomorphometrics to characterize the head structure of corytophanid lizards, based on a time-calibrated phylogeny that includes candidate fossil ancestors. We found evidence of an older diversification of corytophanids than previously reported (~67 vs. ~23.5 MYA) and show that this clade includes two morphological head architectures: (1) Sexually dimorphic crests present in males that are evolving independently from the rest of the head structure, and (2) full integration of the head morphology in monomorphic species. We propose that both architectures are optimal evolutionary trajectories of the parietal crest bones in the head of these lizards. In sexually dimorphic species, these bones are elongated and thinner, and gave rise to the extended crest used in male courtship displays. In monomorphic species, the parietal crest grew thicker in both sexes to allow for a better insertion of muscles associated with a stronger bite.Fil: Taylor, Gregory W.. University Brigham Young; Estados UnidosFil: Santos, Juan C.. St John's University; Estados Unidos. University Brigham Young; Estados UnidosFil: Perrault, Benjamin J.. University Brigham Young; Estados UnidosFil: Morando, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Vásquez Almazán, Carlos Roberto. Universidad de San Carlos de Guatemala; GuatemalaFil: Sites, Jack W.. University Brigham Young; Estados Unido