Amphibians and Squamates From Maastrichtian Cretaceous Iberia

Late Cretaceous (Maastrichtian) amphibians and squamates from northeastern Iberia

Authors:

Blanco et al

Abstract:

Maastrichtian biodiversity of medium- and large-sized terrestrial vertebrates is well known in Europe and, specifically, in the Iberian Peninsula. Regarding small-sized herpetofaunas (lissamphibians and squamates), only a few European sites have yielded a significant amount of fossils, and they are still poorly known from the Iberian Peninsula. Recent fieldwork carried out at several sites exposing the Tremp Formation (Southern Pyrenees) has revealed four new localities yielding microvertebrates. Two of them (L'Espinau and Serrat del Rostiar-1) are relatively diverse in herpetofauna, containing albanerpetontids, four different anurans (two different alytids, a pelobatid or gobiatid and a palaeobatrachid), as well as six types of squamates (including scincomorphs, iguanids, anguids and probably gekkotans). Most of these groups are shared with other Campanian-Maastrichtian localities from eastern Iberia although, in some cases, morphological differences might suggest the presence of new lower-level taxa (i.e., genera or species). Also remarkable is the presence of alytines and likely gekkotans that would represent the oldest records of these taxa in Europe and in the Iberian Peninsula, respectively. Taxa of Laurasian origin are common at the Serrat del Rostiar-1 and L'Espinau localities, while Gondwanan taxa are lacking in all cases. Evidence for Asian immigrants (i.e., alytines) is found amongst anurans. Some differences regarding the faunal composition could be explained by environmental factors (i.e., coastal wetlands vs. fluvial settings), although the possibility of taphonomic biases cannot be ruled out.

Beyond Awesome: Salamander Found in Miocene Neogene Dominican Amber

More than 20 million years ago, a short struggle took place in what is now the Dominican Republic, resulting in one animal getting its leg bitten off by a predator just before it escaped. But in the confusion, it fell into a gooey resin deposit, to be fossilized and entombed forever in amber.

The fossil record of that event has revealed something not known before – that salamanders once lived on an island in the Caribbean Sea. Today, they are nowhere to be found in the entire Caribbean area.

The never-before-seen and now extinct species of salamander, named Palaeoplethodon hispaniolae by the authors of the paper, adds more clues to the ecological and geological history of the islands of the Caribbean. Findings about its brief life and traumatic end – it was just a baby – have been published in the journal Palaeodiversity, by researchers from Oregon State University and the University of California at Berkeley.

“I was shocked when I first saw it in amber,” said George Poinar, Jr., a professor emeritus in the OSU College of Science, and a world expert in the study of insects, plants and other life forms preserved in amber, all of which allow researchers to reconstruct the ecology of ancient ecosystems.

“There are very few salamander fossils of any type, and no one has ever found a salamander preserved in amber,” Poinar said. “And finding it in Dominican amber was especially unexpected, because today no salamanders, even living ones, have ever been found in that region.”

link.

Kiyatriton leshchinskiyi: a Cryptobranchoid Salamander From Aptian/Albian Cretaceous Russia

Kiyatriton leshchinskiyi Averianov et Voronkevich, 2001, a crown-group salamander from the Lower Cretaceous of Western Siberia, Russia

Author:

Skutschas

Abstract:

Crown-group salamander Kiyatriton leshchinskiyi, from the Lower Cretaceous (Aptian–Albian) Ilek Formation of the Shestakovo locality in Western Siberia, Russia, was the first “lissamphibian” discovered from the Mesozoic of Russia and it is the only Early Cretaceous salamander from Asia which was found outside China. In this paper a detailed redescription of type and newly collected material on Kiyatriton leshchinskiyi, consisting fragmentary cranial and postcranial bones is presented. The structure of the atlas, trunk vertebrae and femur suggest that Kiyatriton leshchinskiyi may be a member of the Cryptobranchoidea.

Significant Amphibian Decline in the United States

Trends in Amphibian Occupancy in the United States

Authors:

Adams et al

Abstract:

Though a third of amphibian species worldwide are thought to be imperiled, existing assessments simply categorize extinction risk, providing little information on the rate of population losses. We conducted the first analysis of the rate of change in the probability that amphibians occupy ponds and other comparable habitat features across the United States. We found that overall occupancy by amphibians declined 3.7% annually from 2002 to 2011. Species that are Red-listed by the International Union for Conservation of Nature (IUCN) declined an average of 11.6% annually. All subsets of data examined had a declining trend including species in the IUCN Least Concern category. This analysis suggests that amphibian declines may be more widespread and severe than previously realized.

Maastrichtian Cretaceous Daemon-Frog Beelzebufo: Now Smaller, Armoured

New Material of Beelzebufo, a Hyperossified Frog (Amphibia: Anura) from the Late Cretaceous of Madagascar

Authors:

Evans et al

Abstract:

The extant anuran fauna of Madagascar is exceptionally rich and almost completely endemic. In recent years, many new species have been described and understanding of the history and relationships of this fauna has been greatly advanced by molecular studies, but very little is known of the fossil history of frogs on the island. Beelzebufo ampinga, the first named pre-Holocene frog from Madagascar, was described in 2008 on the basis of numerous disarticulated cranial and postcranial elements from the Upper Cretaceous (Maastrichtian) Maevarano Formation of Madagascar. These specimens documented the presence of a hyperossified taxon that differed strikingly from extant Malagasy frogs in its large size and heavy coarse cranial exostosis. Here we describe and analyse new, articulated, and more complete material of the skull, vertebral column, and hind limb, as well as additional isolated elements discovered since 2008. μCT scans allow a detailed understanding of both internal and external morphology and permit a more accurate reconstruction. The new material shows Beelzebufo to have been even more bizarre than originally interpreted, with large posterolateral skull flanges and sculptured vertebral spine tables. The apparent absence of a tympanic membrane, the strong cranial exostosis, and vertebral morphology suggest it may have burrowed during seasonally arid conditions, which have been interpreted for the Maevarano Formation from independent sedimentological and taphonomic evidence. New phylogenetic analyses, incorporating both morphological and molecular data, continue to place Beelzebufo with hyloid rather than ranoid frogs. Within Hyloidea, Beelzebufo still groups with the South American Ceratophryidae thus continuing to pose difficulties with both biogeographic interpretations and prior molecular divergence dates.

Carboniferous Lepospondyls did not Undergo Metamorphosis

Morphometric analysis of skeletal growth in the lepospondyls Microbrachis pelikani and Hyloplesion longicostatum (Tetrapoda, Lepospondyli)

Authors:

Jennifer C. Olori

Abstract:

Although morphological evidence alone appears insufficient to resolve the problem of extant amphibian ancestry, comparison of developmental processes and functional correlates of ontogenetic change may provide a basis for evaluating relationships among extinct and extant tetrapods. In the first allometric study of cranial and postcranial growth in any lepospondyl, I investigate skeletal development in the microsaurs Microbrachis pelikani and Hyloplesion longicostatum using traditional measurement-based and geometric morphometric analyses. Regression analyses against both skull and centrum lengths for M. pelikani indicate positive allometric scaling of the interclavicle plate length, pubis, and ilium, and negative scaling of the diameter of the orbit. Preliminary data for H. longicostatum support negative scaling of neural arch height and posterior centrum height. Results from geometric morphometrics suggest slight widening of the cheek in M. pelikani, rather than marked elongation. Overall, cranial and postcranial growth in both microsaurs was primarily isometric and comparison with allometric data from other Paleozoic taxa suggests that isometric growth is an ancestral feature of development in early tetrapods. All regression analyses for M. pelikani and H. longicostatum had a constant linear slope, indicating that ontogenetic trajectories were continuous, with gradual skeletal growth and no shift in feeding or locomotor function during ontogeny. The lack of morphological change suggests that these microsaurs did not undergo an extant amphibian-like metamorphosis that included reorganization of the skeleton. These data support the hypothesis that metamorphosis is a derived mode of development present only in extant amphibians and their closest relatives.

The Launching of FROGEE

A legit pic from here. 

Baumgartner better watch out!  The webbed ones want his record!

De-Extinction: Bringing Back the Gastric Brooding Frog and Thycaline

Hula Painted Frog is Not Extinct...and Not Related to What We Thought

The first amphibian to have been officially declared extinct by the International Union for Conservation of Nature (IUCN) has been rediscovered in the north of Israel after some 60 years and turns out to be a unique "living fossil," without close relatives among other living frogs.

The Hula painted frog was catalogued within the Discoglossus group when it was first discovered in the Hula Valley of Israel in the early 1940s. The frog was thought to have disappeared following the drying up of the Hula Lake at the end of the 1950s, and was declared extinct by the IUCN in 1996. As a result, the opportunity to discover more about this species' history, biology and ecology was thought to have disappeared.

However, a team of Israeli, German and French researchers now report in the scientific journal Nature Communications on an in-depth scientific analysis of this enigmatic amphibian.

Based on new genetic analyses of rediscovered individuals and the morphologic analyses of extant and fossil bones, the conclusion is that the Hula frog differs strongly from its other living relatives, the painted frogs from northern and western Africa. Instead, the Hula frog is related to a genus of fossil frogs, Latonia, which were found over much of Europe dating back to prehistoric periods and has been considered extinct for about a million years,

The results imply that the Hula painted frog is not merely another rare species of frog, but is actually the sole representative of an ancient clade of frogs (a group with a single common ancestor)

Are Modern Amphibians Really Lepospondyls?

The origin(s) of extant amphibians: a review with emphasis on the “lepospondyl hypothesis”

Authors:

1. David MARJANOVIĆ (a,b)
2. Michel LAURIN (a)

Affiliations:

a. UMR 7207, CNRS/MNHN/UPMC/Collège de France, Département Histoire de la Terre, case postale 48, 57 rue Cuvier, F-75231 Paris cedex 05, France

b. Abteilung Forschung, Museum für Naturkunde, Leibniz-Institut für Evolutions- und Biodiversitätsforschung, Invalidenstraße 43, D-10115 Berlin, Germany

Abstract:

The origins of the extant amphibians (frogs, salamanders, caecilians) remain controversial after over a century of debate. Three groups of hypotheses persist in the current literature: the “temnospondyl hypothesis” (TH) which roots Lissamphibia Haeckel, 1866 (the smallest clade composed of the extant amphibians) within the Paleozoic temnospondyls, the “lepospondyl hypothesis” (LH) which postulates a monophyletic Lissamphibia nested within the Paleozoic lepospondyls, and the “polyphyly hypothesis” (PH), according to which the frogs and the salamanders are temnospondyls while the caecilians are lepospondyls. The discovery of the Middle Jurassic to Pliocene albanerpetontids, which are very similar to the extant amphibians, has complicated rather than resolved this situation. We present a review of recent publications and theses in this field, several of which show more support for the LH than for the TH and considerably more than for the PH. In addition, we show that there is no particular attraction between long-bodied lissamphibians (caecilians) and long-bodied lepospondyls (such as the lysorophians): when they are removed from two published matrices, reanalyses nonetheless find the LH. In one case the LH is found even when all salamanders are removed as well. We furthermore propose that the complex of characters called the salamander mode of autopodium development is (in its less extreme forms) plesiomorphic for limbed vertebrates, so the apparent presence of this mode of development in temnospondyls cannot support the TH or the PH. Still, a consensus will not be reached soon, despite the increasing range of data and types of analysis that are used (morphological, molecular and combined phylogenetics, development biology, molecular divergence dating, paleontological supertree dating, combined dating, and calculation of confidence intervals on first appearances in the fossil record). We present examples of pertinent character state distributions and explore a large gap in the fossil record of small stegocephalians

Warning: the title link is to a PDF.

Chrytid Fungus Reservoir Discovered...and its bad news

Scientists have found a new culprit in spreading the disease that's been driving the world's frogs to the brink of extinction: crayfish.

In the last few decades, the disease caused by the chytrid fungus has been a disaster for frogs and other amphibians. More than 300 species are nearly extinct because of it. Many probably have gone extinct, but it can be difficult to know for sure when a tiny, rare species disappears from the face of the Earth.

"This pathogen is bad news. It's worse news than any other pathogen in the history of life on Earth as far as we know it," says Vance Vredenburg, a conservation biologist at San Francisco State University who studies frogs but did not work on the new study.

The chytrid fungus was only discovered in the late 1990s. Since then, scientists have been scrambling to figure out how it spreads and how it works.

One of the biggest mysteries is how chytrid can persist in a frogless pond. Researchers saw it happen many times and were perplexed: If all of a pond's amphibians were wiped out, and a few frogs or salamanders came back and recolonized the pond, they would also die—even though there were no amphibians in the pond to harbor the disease.

One possible reason is that chytrid infects other animals. For a study published today in Proceedings of the National Academy of Sciences, Taegan McMahon, a graduate student in ecology at the University of South Florida in Tampa, looked at some possible suspects and focused on crayfish, those lobsterlike crustaceans living in freshwater. They seemed like a good possibility because they're widespread and because their bodies have a lot of keratin, a protein the fungus attacks.

In the lab, McMahon exposed crayfish to the disease and they got sick. More than a third died within seven weeks, and most of the survivors were carrying the fungus. She also put infected crayfish in the water with tadpoles—separated by mesh, so the crustaceans wouldn't eat the baby frogs—and the tadpoles got infected. When McMahon and her colleagues checked out wetlands in Louisiana and Colorado, they also found infected crayfish.

That means crayfish can probably act as a reservoir for the disease. The fungus seems to be able to dine on crayfish then leap back to amphibians when it gets a chance. No one knows for sure where the fungus originally came from or why it's been such a problem in recent decades, but this research suggests one way that it could have been spread. Crayfish are sometimes moved from pond to pond as fish bait and are sold around the world as food and aquarium pets.

Climate Change Could Devastate Tropical Frogs

Most of the more than 6,000 species of frogs in the world lay their eggs in water. But many tropical frogs lay their eggs out of water. This behavior protects the eggs from aquatic predators, such as fish and tadpoles, but also increases their risk of drying out. Justin Touchon, post-doctoral fellow at the Smithsonian Tropical Research Institute, discovered that climate change in Panama may be altering frogs' course of evolution.

By analyzing long-term rainfall data collected by the Panama Canal Authority, Touchon discovered that rainfall patterns are changing just as climate-change models predict.

"Over the past four decades, rainfall has become more sporadic during the wet season," said Touchon. "The number of rainy days decreased, and the number of gaps between storms increased."

The eggs of the pantless treefrog, Dendropsophus ebraccatus, are extremely susceptible to drying. The embryos die within a day when there is no rain. Heavy rains trigger breeding, so as storms become sporadic, the chance of rain within a day of being laid decrease and so does egg survival.

As weather patterns have changed, the advantage of laying eggs out of water has decreased, not only for pantless treefrogs but potentially for many species. "Pantless treefrogs can switch between laying eggs in water or on leaves, so they may weather the changes we are seeing in rainfall better than other species that have lost the ability to lay eggs in water," said Touchon. "Being flexible in where they put their eggs gives them more options and allows them to make decisions in a given habitat that will increase the survival of their offspring."

Is Lissamphibia Paraphyletic?

(cladogram from here)

If Eocaecilia nests within Lepospondyli...that would mean that Caecilians are not closely related to salamanders and frogs at all.

How accepted (or not) is this?

Cali-Texan Hybrid Salamander Super Predator

A and B are the largest of the native california tiger salamanders. Note D is the hybrid. Holy shibbit. Picture from National Geographic.

Invasive hybrid tiger salamander genotypes impact native amphibians

1. Maureen E. Ryan (a,1)
2. Jarrett R. Johnson (a)
3. Benjamin M. Fitzpatrick (b)

a. Center for Population Biology, University of California, Davis, CA 95616; and
b. Ecology and Evolutionary Biology, University of Tennessee, Knoxville, TN 37996

Abstract:

Although the ecological consequences of species invasions are well studied, the ecological impacts of genetic introgression through hybridization are less understood. This is particularly true of the impacts of hybridization on “third party” community members not genetically involved in hybridization. We also know little about how direct interactions between hybrid and parental individuals influence fitness. Here, we examined the ecological effects of hybridization between the native, threatened California Tiger Salamander (Ambystoma californiense) and the introduced Barred Tiger Salamander (Ambystoma tigrinum mavortium). Native x introduced hybrids are widespread in California, where they are top predators in seasonal ponds. We examined the impacts of early generation hybrids (first 2 generations of parental crosses) and contemporary hybrids derived from ponds where hybrids have been under selection in the wild for 20 generations. We found that most classes of hybrid tiger salamander larvae dramatically reduced survival of 2 native community members, the Pacific Chorus Frog (Pseudacris regilla) and the California Newt (Taricha torosa). We also found that native A. californiense larvae were negatively impacted by the presence of hybrid larvae: Native survival and size at metamorphosis were reduced and time to metamorphosis was extended. We also observed a large influence of Mendelian dominance on size, metamorphic timing and predation rate of hybrid tiger salamanders. These results suggest that both genetic and ecological factors are likely to influence the dynamics of admixture, and that tiger salamander hybridization might constitute a threat to additional pond-breeding species of concern in the region.

1. To whom correspondence should be addressed. E-mail: meryan@ucdavis.edu

I think this goes beyond introgression. That there is such a huge difference in phenotype is just amazing.

Amazonian Amphibian Diversity Traced to Andes

Colorful poison frogs in the Amazon owe their great diversity to ancestors that leapt into the region from the Andes Mountains several times during the last 10 million years, a new study from The University of Texas at Austin suggests.

This is the first study to show that the Andes have been a major source of diversity for the Amazon basin, one of the largest reservoirs of biological diversity on Earth. The finding runs counter to the idea that Amazonian diversity is the result of evolution only within the tropical forest itself.

"Basically, the Amazon basin is a 'melting pot' for South American frogs," says graduate student Juan Santos, lead author of the study. "Poison frogs there have come from multiple places of origin, notably the Andes Mountains, over many millions of years. We have shown that you cannot understand Amazonian biodiversity by looking only in the basin. Adjacent regions have played a major role."

Santos and Dr. David Cannatella, professor of integrative biology, published their findings this month in the journal PLoS Biology.

The tale of how the tropics became so diverse is a rather complicated one indeed.

Tropical Salamander Implosion

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

1. Sean M. Rovitoa,
2. Gabriela Parra-Oleaa,b,
3. Carlos R. Vásquez-Almazánc,
4. Theodore J. Papenfussa and
5. David B. Wakea,1

-Author Affiliations

1.
aMuseum of Vertebrate Zoology and Department of Integrative Biology, University of California, Berkeley, CA 94720-3160;
2.
bInstituto de Biología, Universidad Nacional Autónoma de México, AP 70-153, Ciudad Universitaria, CP 04510 México DF, México; and
3.
cMuseo de Historia Natural, Universidad de San Carlos, Calle Mariscal Cruz 1-56, Zona 10, Cuidad de Guatemala, Guatemala

1.

Contributed by David B. Wake, December 20, 2008 (sent for review November 20, 2008)

Abstract

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.

I had hoped that the salamanders et al would not be declining the frogs have been, but that's obviously not the case. In a case of horrifying and hopefully very wrong linear extrapolation, could we be on the verge of
seeing that ancient lineage finally snuffed out? Depressing that thought is.

Frog-Salamander Split Fossil Found?

The description of an ancient amphibian that millions of years ago swam in quiet pools and caught mayflies on the surrounding land in Texas has set to rest one of the greatest current controversies in vertebrate evolution. The discovery was made by a research team led by scientists at the University of Calgary.

The examination and detailed description of the fossil, Gerobatrachus hottoni (meaning Hotton’s elder frog), proves the previously disputed fact that some modern amphibians, frogs and salamanders evolved from one ancient amphibian group called temnospondyls.

The discovery is described for the first time in the prestigious international research journal Nature.

“The dispute arose because of a lack of transitional forms. This fossil seals the gap,” says Jason Anderson, assistant professor, University of Calgary Faculty of Veterinary Medicine and lead scientist in the study.

The Gerobatrachus fossil provides a much fuller understanding of the origin and evolution of modern amphibians. The skull, backbone and teeth of Gerobatrachus have a mixture of frog and salamander features—the fossil has two fused bones in the ankle, which is normally only seen in salamanders, and a very large tympanic ear (ear drum). It also has a lightly built and wide skull similar to that of a frog. Its backbone is exactly intermediate in number between the modern frogs and salamanders and more primitive amphibians.

The new fossil also addresses a controversy over molecular clock estimates, or the general time salamanders and frogs evolved into two distinct groups.

“With this new data our best estimate indicates that frogs and salamanders separated from each other sometime between 240 and 275 million years ago, much more recently than previous molecular data had suggested,” says Robert Reisz, professor, University of Toronto Mississauga and second author on the paper.

Another clash between the molecular biologist types and paleongtologists. Temnospondyls, salamanders, and frogs, oh my!