Sunday, November 19, 2017

The eye covering on snakes

The eye of all snakes is covered by a transparent spectacle that originates from the fusion of the eyelids during embryonic development. It is generally believed that the spectacle arose as an evolutionary adaptation to protect the eyes of early fossorial snakes. However, given that extant snakes occur in a variety of habitats with some species being almost exclusively fossorial, aquatic or terrestrial, and display diverse activity patterns where some species are nocturnal and others primarily active during the day, it is reasonable to expect substantial interspecies and adaptive differences in the requirement of the spectacle in terms of providing physical protection of the eye or partaking in visual optics.

Da Silva et al. (2017) have recently demonstrated an excellent correlation between measurements of spectacle thickness collected via optical coherence tomography (OCT), a non-contact medical imaging technology where reflected light is used to produce detailed cross-sectional images of biological tissue and those measured by light microscopy of formalin-fixed specimens. In order to determine variations in spectacle thickness among species, the spectacles of 217 alcohol-preserved museum specimens of 44 species belonging to 14 different families underwent optical coherence tomography (OCT) to measure spectacular thickness. Multivariable analyses were made to determine whether family, activity period (diurnal/nocturnal) and habitat (arboreal/terrestrial/fossorial/aquatic) influenced spectacle thickness.

The thinnest spectacle in absolute terms was found in the Usambara bush viper (Viperidae) with a thickness of 74 ± 9 μm and the absolute thickest spectacle was found in the red-tailed pipe snake (Cylindrophiidae) which had a spectacle thickness of 244 ± 57 μm. Fossorial and aquatic snakes had significantly thicker spectacles than arboreal and terrestrial snakes. When spectacle thickness was correlated to eye size (horizontal spectacle diameter), Gray’s earth snake (Uropeltidae) had the lowest ratio (1:7) and the cottonmouth (Viperidae) had the highest ratio (1:65). Multivariable and phylogenetic analyses showed that spectacular thickness could be predicted by taxonomic family and habitat, but not activity period.

This phylogenetically broad systematic study of the thickness of the snake spectacle showed that spectacular thickness varies greatly across snake species and may reflect evolutionary adaptation and development.

Citation
Da Silva MA, Heegaard S, Wang T, Gade JT, Damsgaard C, Bertelsen MF. 2017. Morphology of the snake spectacle reflects its evolutionary adaptation and development. BMC Veterinary Research. 13(1):258.

Thursday, November 16, 2017

River valleys and snake genetics

Pituophis catenifer sayi
The genetic population structure of snakes can vary markedly based on a number of intrinsic and extrinsic factors. Some snake species show only very modest levels of subdivision or none at all, while others show a high degree of differentiation over small spatial scales. The variation among species is likely due to a wide variety of biological traits (e.g. natal philopatry, home range size, specific habitat requirements), as well as the ability of individuals to disperse. Dispersal and associated gene flow among breeding groups may also be influenced by extrinsic factors such as natural or man-made barriers.  It is only recently that snake populations at range peripheries or in extreme environments have become the focus of conservation genetics studies. Conservation challenges may be exacerbated for populations at range peripheries, where extreme environments and naturally sparse distributions interact with anthropogenic activities to generate additional risk factors.

Snake populations at the northern limits of their range face ecological challenges that may affect dispersal, gene flow, and ultimately genetic population structure. For example, snakes at higher latitudes in North America and Eurasia rely heavily on a limited number of suitable hibernacula to survive harsh winters, and they often exhibit high fidelity to these sites (e.g. Elaphe obsoleta obsoleta, Gloydius halys). In addition, landscapes containing both suitable hibernacula and summer habitat for northern snakes may be patchily distributed at range margins, a situation that is exacerbated by human activities that cause habitat loss and fragmentation. Thus, gene flow may only occur among northern snake populations when individuals travel long distances away from dens to breed; however, successful dispersal may be uncommon, resulting in highly subdivided populations. Interestingly, several recent studies have shown that some snake species have much larger home ranges and travel long distances from hibernacula at northern range limits. In principle, these behavioral traits may partially counteract the barriers to gene flow discussed above. Understanding this situation is of key interest in Canada, where a variety of North American snakes, some of which are of conservation concern, reach their northern range limits.

On the North American Great Plains, several snake species reach their northern range limit where they rely on sparsely distributed hibernacula located in major river valleys. Independent colonization histories for the river valleys and barriers to gene flow caused by the lack of suitable habitat between them may have produced genetically differentiated snake populations. In a recent paper Somers et al (2017) test this hypothesis, using 10 microsatellite loci to examine the population structure of two species of conservation concern in Canada: the eastern yellow-bellied racer (Coluber constrictor flaviventris) and bullsnake (Pituophis catenifer sayi) in 3 major river valleys in southern Saskatchewan. Fixation indices (FST) showed that populations in river valleys were significantly differentiated for both species (racers, FST = 0.096, P = 0.001; bullsnakes FST = 0.045–0.157, P = 0.001). Bayesian assignment (STRUCTURE) and ordination (DAPC) strongly supported genetically differentiated groups in the geographically distinct river valleys. Finer-scale subdivision of populations within river valleys was not apparent based on their data, but is a topic that should be investigated further. The findings highlight the importance of major river valleys for snakes at the northern extent of their ranges and raise the possibility that populations in each river valley may warrant separate management strategies.

Citation
Somers CM, Graham CF, Martino JA, Frasier TR, Lance SL, Gardiner LE, et al. (2017) Conservation genetics of the eastern yellow-bellied racer (Coluber constrictor flaviventris) and bullsnake (Pituophis catenifer sayi): River valleys are critical features for snakes at northern range limits. PLoS ONE12(11): e0187322. https://doi.org/10.1371/journal.pone.0187322

Saturday, November 4, 2017

The origin of Australian squamates


Eastern Tiger Snake, Notechis scutatus
Deadly snakes are among Australia's most iconic animals. Now a new study led by The Australian National University (ANU) has helped explain how they descended from creatures that have come from Asia over the past 30 million years.

Lead researcher Dr Paul Oliver said about 85 percent of more than 1,000 snake and lizard species in Australia descended from creatures that floated across waters from Asia to Australia.

The research helps explain how Australia has become home to about 11 percent of the world's 6,300 reptile species -- the highest proportion of any country around the world.

"Around 30 million years ago it appears that the world changed, and subsequently there was an influx of lizard and snakes into Australia," said Dr Oliver from the ANU Research School of Biology.

"We think this is linked to how Australia's rapid movement north, by continental movement standards, has changed ocean currents and global climates."

The researchers conducted the study using animal tree-of-life data combined with empirical evidence and simulations.

The origins for reptiles contrast with other famous Australian animal groups including marsupials and birds, which include many more species descended from ancestors that lived on Gondwana, a supercontinent that included Australia, Antarctica, South America, Africa and Madagascar.

Dr Oliver said that the study found that the immigration of reptiles into Australia was clustered in time.

"The influx of lizards and snakes into Australia corresponds with a time when fossil evidence suggests animal and plant communities underwent major changes across the world," he said.

"The movement of Australia may have been a key driver of these global changes."

Oliver PM, Hugall AF. 2017. Phylogenetic evidence for mid-Cenozoic turnover of a diverse continental biota. Nature Ecology & Evolution, 2017; DOI: 10.1038/s41559-017-0355-8

Thursday, November 2, 2017

Marine Snake Diversity in the Straits of Malacca and the South China Sea

Bar graph showing the species composition and relative abundance
 for 852 marine snakes collected as by-catch from otter trawlers 
operating on the  trawling grounds at Sungai Buloh. The snakes 
were collected in 1971 and 1974-75 and represented 10 species 
of true sea snake (Elapidae) and one species of file snake 
(Acrochordidae). The assemblage is strongly dominated by 
Hydrophis curtus (see inset in figure, FMNH 202179) that made 
up 82% of the snake by-catch. The three most common species, 
Hydrophis curtus, Acrochordus granulatus, and Hydrophis 
caerulescensmade up 95% of the sample. 
The following is the abstract from the paper cited below. Prior to World War II, traditional hand-operated fishing methods prevailed throughout Southeast Asia. However, by 1950, mechanized diesel-powered trawlers were being introduced and the modern boom-and bust of fisheries was set into motion. Besides targeted fish, squid, and prawns, otter trawls on the bottom brought up a vast diversity of demersal by-catch including marine snakes. This paper reports on the diversity of the marine snake by-catch obtained from otter trawlers operating at two locations in the Straits of Malacca (Sungai Buloh and Parit Botak) and one location on the eastern coast of the Malay Peninsula (Endau) in the mid-1970s. At Sungai Buloh 11 species of snakes were observed and a single species, Hydrophis curtus, strongly dominated the assemblage, comprising 82% of the by-catch. Eleven species were also observed in the by-catch from Parit Botak but there, three species (Hydrophis fasciatus, H. curtus, and Aipysurus eydouxii) shared dominance with each making up more than 22% of the assemblage. At Endau, 13 species appeared in the by-catch and two species (H. curtus and Hydrophis viperinus) dominated, comprising 33% and 32% of the catch respectively. Besides differences between locations, some small differences in species diversity were detected between collection periods at Sungai Buloh. In addition, a review is undertaken of published trawl surveys of marine snakes in Southeast Asia in the context of the steady depletion of fisheries in the region that took place in the second half of the twentieth century. This review emphasizes that marine snake species diversity needs to be understood on a relatively fine spatial scale and in the context of the health of the fishery as a whole. The entire paper can be found here.

Citation
Voris HK. 2017. Diversity of Marine Snakes on Trawling Grounds in the Straits of Malacca and the South China Sea. Tropical Natural History 17(2):65-87.

Monday, October 30, 2017

The Rediscover of Jackson’s Climbing Salamander (Bolitoglossa jacksoni)

The Search for Lost Species initiative is today celebrating the incredible and unexpected rediscovery of the first of its top 25 “most wanted” lost species, the Jackson’s Climbing Salamander (Bolitoglossa jacksoni), lost to science since its discovery in 1975. The rediscovery comes months before an organized expedition to Guatemala’s Cuchumatanes Mountain range to look for the animal, and was made possible in part because a group of organizations, including Global Wildlife Conservation and Rainforest Trust, established the Finca San Isidro Amphibian Reserve in 2015 to help protect the species’ habitat.
Photo by Carlos Vasquez Almazan

“I love this story because it conveys how protecting habitat gives species a fighting chance to survive on this planet,” said Don Church, president of GWC and Search for Lost Species lead. “This rediscovery can only be a good omen for the future of the Search for Lost Species campaign. It’s a sign that if we get out there and work at it, many of these species can be found and saved.”

A guard at the Finca San Isidro Amphibian Reserve, Ramos León, discovered a juvenile Jackson’s climbing salamander—only the third individual ever seen—on the edge of the reserve while out on patrol this month. He sent a photo to Carlos Vasquez, curator of herpetology at USAC University in Guatemala and coordinator of the amphibian conservation program at local NGO and GWC partner FUNDAECO, who confirmed that the species in the photo was, indeed, the Jackson’s climbing salamander.

Vasquez has been on more than 30 trips to find the species, nicknamed the “golden wonder” for its brilliant yellow hues, since 2005, spending more than 3,000 hours in search of it. Earlier this year he led a workshop for the reserve’s four guards to show them photos of the salamander and to discuss where they may find it—in moss, leaves or bark—while out on patrol in the reserve during the rainy season. His efforts paid off.

“I explained to them how important this species is and I left a poster there so they could see a picture of the Jackson’s climbing salamander every single day,” Vasquez said. “We had started to fear that the species was gone, and now it’s like it has come back from extinction. It’s a beautiful story, and marks a promised future for the conservation of this special region.”

The guard rediscovered the salamander 300 meters higher than where the species was discovered in 1975 by Jeremy Jackson (after whom the salamander is named) and Paul Elias, two American friends who spent time exploring the jungles of Guatemala in the 1970s. On their adventures, they also discovered the Finca Chiblac salamander and the long-limbed salamander. All three species went unseen for more than three decades until Vasquez rediscovered the Finca Chiblac salamander in 2009 and the long-limbed salamander in 2010. The Jackson’s climbing salamander was the last of the missing triad.

In 2015, spurred by the 2014 expedition and the earlier rediscovery of the Finca Chiblac salamander and the long-limbed salamander, a consortium of international groups—GWC, MUSHNAT, FUNDAECO World Land Trust, Rainforest Trust, the International Conservation Fund of Canada and the Amphibian Survival Alliance—established the Finca San Isidro Reserve (also called the Yal Unin Yul Witz Reserve) to protect some of the last remaining habitat for the species.

“When 40 years later [after we discovered the species] as an act of faith, a tract of land next to where we discovered it was protected, we all held our breath hoping that this exceptional phantom would reappear,” said Elias, who today is a partner at a private investment firm in Boston. “The rediscovery of this rarest of the rare shows how important habitat preservation is to the persistence of these special animals in these exceptional places, and for me personally it is a moment of sheer joy.”

Global Wildlife Conservation, FUNDAECO and Rainforest Trust are now joining forces to expand the reserve to protect the Jackson’s climbing salamander and a treasure trove of additional endemic and endangered Guatemalan species threatened by climate change, habitat loss and infectious disease. GWC will be launching a #GivingTuesday fundraising campaign in November to help support the expansion of the reserve.

In the meantime, Vasquez and team are conducting research where the salamander was found to better understand the species’ ecology and will continue to spend time in the field to look for additional individuals to assess the population.

Western Rat Snakes and Resource Selection

 Western Ratsnakes (Pantherophis obsoletus)
Predicting the effects of global climate change on species interactions has remained difficult because regional climate models and the microclimates experienced by organisms are not always in sync. In a new paper George et al. (2017) evaluated resource selection in a predominant ectothermic predator using a modeling approach that permitted them to assess the importance of habitat structure and local real-time air temperatures within the same modeling framework. The authors radio-tracked 53 western ratsnakes (Pantherophis obsoletus) from 2010 to 2013 in central Missouri, USA. The researchers used study sites where this species was previously linked to prey population demographics.  Bayesian discrete choice models within an information theoretic framework were used to evaluate the seasonal effects of fine-scale vegetation structure and thermal conditions on ratsnake resource selection. Ratsnake resource selection was influenced most by canopy cover, canopy cover heterogeneity, understory cover, and air temperature heterogeneity. Ratsnakes preferred habitats with greater canopy heterogeneity early in the active season, and greater temperature heterogeneity later in the season. This seasonal shift potentially reflects differences in resource requirements and thermoregulation behavior. Predicted patterns of space use indicate that ratsnakes preferentially selected open habitats in spring and early summer and forest–field edges throughout the active season. The results show that downscaled temperature models can be used to enhance our understanding of animal resource selection at scales that can be addressed by managers. The authors suggest that conservation of snakes or their prey in a changing climate will require consideration of fine-scale interactions between local air temperatures and habitat structure.

Citation
George AD, Connette GM, Thompson FR, Faaborg J. 2017. Resource selection by an ectothermic predator in a dynamic thermal landscape. Ecology and Evolution. 2017.

Friday, October 27, 2017

A new, hybrid, all female whiptail that is tetraploid


The Desert Grasslands Whiptail, Aspidoscelis inornatus. 
In a new paper, Cole et al. (2017) describe the second known tetraploid amniote that reproduces by parthenogenetic cloning. This all-female species of whiptail lizard originated in the laboratory from hybridization between the  Little Striped Whiptail, Aspidoscelis uniparens (triploid parthenogen) and the Desert Grasslands Whiptail, Aspidoscelis inornatus (diploid bisexual species). Similar clonal lineages of tetraploids arose from at least 44 F1 hybrid females. These were produced by at least 15 Aspidoscelis uniparens that mated with several different males of Aspidoscelis inornatus from both New Mexico and Arizona stock.

Inheritance of alleles at eight microsatellite deoxyribonucleic acid (msDNA) loci in the tetraploid species confirms its parentage, whereas DNA quantification and behavior of chromosomes in meiosis demonstrate that tetraploidy and heterozygosity are maintained generation after generation.

The authors compared univariate and multivariate variation in scalation between the tetraploids, their parental taxa, and four museum specimens from New Mexico that were reported as putative hybrids. Two of the putative hybrids are confirmed as such, but the other two are the Little Striped Whiptail, Aspidoscelis inornatus and the Desert Grasslands Whiptail, Aspidoscelis uniparens. The similarities of Aspidoscelis uniparens and the tetraploids suggest that tetraploid females may exist in old samples misidentified as Aspidoscelis uniparens. Clones of the tetraploid species are so similar to each other in morphology and msDNA that they authors could not distinguish most individuals or separate lineages from the P1 through multiple generations (up to F7) on the basis of the 12 msDNA loci analyzed in this study.

Discussion of the taxonomic aspects of the multiple hybrid origins of similar clones concludes that one specific name should be applied to all of them. For some systematists, depending on the species concept preferred, these lizards represent a complex of multiple cryptic species that cannot be reliably identified or diagnosed (one species for each F1 hybrid female that cloned a lineage). These specimens of known parentage provide valuable insights for the taxonomic treatment of natural parthenogenetic clones. In addition, the authors show that the degree of morphological variation in clonal parthenogens and bisexual Aspidoscelis inornatus can be similar to each other. They provide a new name for this new species, Priscilla’s Whiptail Lizard, Aspidoscelis priscillae.

Citation
Cole CJ, Taylor HL, Neaves WB, Baumann DP, Newton A, Schnittker R, Baumann P. The Second Known Tetraploid Species of Parthenogenetic Tetrapod (Reptilia: Squamata: Teiidae): Description, Reproduction, Comparisons With Ancestral Taxa, And Origins Of Multiple Clones. Bulletin of the Museum of Comparative Zoology. 2017 Oct 17;161(8):285-321.

Thursday, October 26, 2017

The endangered Lanceheads of Martinique


Martinique Lancehead, Bothrops lanceolatus.
Photo credit Nathalie Dewynter
In a new paper, Gros-Désormeaux et al. discuss the impact of humans on the Martinique Lancehead, Bothrops lanceolatus. The lancehead is the only poisonous snake endemic to Martinique, Lesser Antilles arc. Today, this snake is on the verge of extinction. The recorded number of snakes killed yearly between 1970 and 2002 decreased by 97%. Despite the production of an antivenom in 1993, the local authorities set up a financial reward to encourage the eradication of lancehead snakes. Today the local population still perceives the snake as a threat, due to its fatal venom and its fierce behaviour. The case study of the lancehead in Martinique highlights the need to develop integrated strategies to conserve poisonous snakes on densely populated islands. This requires innovative, cross-sectoral strategies that involve decision-makers working along with multi-disciplinary scientists. Approaching the complexity of ecosystems through the socio-ecological prism implies, conversely, linking up the domains of science and technology, life and environmental sciences, and human and social sciences, through interactions based on sharing common assumptions

Citation
Gros-Désormeaux JR, Lagabrielle E, Lesales T, Exilie I, Tupiassu L, Béchacq D. Living with or Eradicating Poisonous Snakes in Densely Populated Caribbean Islands—A Socio-Ecological Challenge for the French West Indies. Open Journal of Animal Sciences. 2017 Sep 4;7(04):405.

Wednesday, October 25, 2017

Fossil snakes from the Bahamas


Nerodia clarki
The late Pleistocene snake fossils from Sawmill Sink (Abaco, The Bahamas) represent five taxa: a blindsnake or threadsnake (Scolecophidia); the Abaco boa (Boidae: Chilabothrus cf. exsul); a rat snake (Colubridae: Pantherophis sp.); a water snake (Natricidae: Nerodia sp.); and the Cuban racer (Dipsadidae: Cubophis cf. vudii). A scolecophidian, lChilabothrus exsul, and Cubophis vudii still exist on Abaco and have been previously recovered in fossil deposits in the West Indies. In contrast, no forms of Pantherophis or Nerodia have been reported as fossils anywhere in the West Indies until now. This is the first evidence of any indigenous species of Pantherophis (living or extinct) in the Caribbean, whereas the only indigenous Nerodia in the West Indies is the extant N. clarkii along the northern coast of Cuba. In being present on Abaco in late Pleistocene but not Holocene contexts, Pantherophis sp. and Nerodia sp. resemble 17 species of birds that apparently did not survive the dramatic changes in climate, habitat, and land area associated with the Pleistocene–Holocene Transition in The Bahamas. It is likely that Pleistocene fossils of both Pantherophis and Nerodia will be found eventually on other Bahamian islands. With the discovery of these two snakes, the vertebrate fauna of Sawmill Sink now stands at 97 species, by far the richest in the West Indies.

Citation
Mead JI, Steadman DW. Late Pleistocene snakes (Squamata: Serpentes) from Abaco, The Bahamas. Geobios. 2017 Oct 10.

A warming climate and viviparous lizards


Phrynocephalus sp.
Climate change is and will continue to have a negatively impacting biodiversity. In a new paper Wang et al. (2017) note that lizards may experience population declines and extinctions on a similar scale to that experienced by amphibians.  Within lizards, viviparous species are hypothesized to be more vulnerable to climate warming, because they have evolved reduced body temperature and heat tolerance, but this idea remains untested. To test this hypothesis, Wang et al. conducted three temperatures (20, 24, and 28 °C) factorial designed experiments on two lizard species Phrynocephalus przewalskii (oviparous) and P. putjatia (viviparous). The experiments simulated warming on oviparous versus viviparous lizards. Their manipulation of ambient temperature affected activity and thermal preference in both species, birth dates in P. putjatia, and egg mass in P. przewalskii. The other examined traits (fecundity, reproductive output, and size, morphology, and sprint speed of offspring) were not affected. Neither lizard species showed different behavioral responses to rising temperatures between the sexes. The viviparous species thermoregulated more actively than did the oviparous species, but the two species did not differ in thermal preference. Warming reduced the activity time allotted for thermoregulation in both species, but the effect was more dramatic in the viviparous species. Their data supports one of the central predictions that lead to the hypothesis that viviparous lizards are more vulnerable to climate warming. Warming constrains activity more dramatically in viviparous species, not because viviparous lizards have evolved reduced body temperature and heat tolerance.

Citation
Wang Z, Ma L, Shao M, Ji X. Are viviparous lizards more vulnerable to climate warming because they have evolved reduced body temperature and heat tolerance?. Oecologia. 2017 Oct 10:1-0.

Monday, September 25, 2017

Caribbean Ameivas moved to the genus Pholidoscelis



The family Teiidae is a New World clade of small to large-sized lizards that tend to be active foragers, diurnal, and omnivorous. Whiptails (genus Aspidocelis)in the USA, Racerunners (genus Cnemidophorus) in the Neotropics, the giant Tegus (Tupinmabis and Salvator) in the Neotropics are a few of the major clades. The Ameiva's are primarily Neotropical but also are well represented in the West Indies. In a new paper Tucker et al. (2017) examine the phylogenetic relationships and biogeographic history of Caribbean island ameivas and place them in the genus Pholidoscelis. The authors use phylogenomic and mitochondrial DNA datasets to reconstruct a well-supported phylogeny and assess historical colonization patterns in the group. They obtained sequence data from 316 nuclear loci and one mitochondrial marker for 16 of the 19 extant species of the Caribbean endemic genus Pholidoscelis. To estimate divergence times, they used fossil teiids to calibrate a timetree which was used to elucidate the historical biogeography of these lizards. All phylogenetic analyses recovered four well-supported species groups (clades) recognized previously and supported novel relationships of those groups, including a (P. auberi + P. lineolatus) clade (western + central Caribbean), and a (P. exsul + P. plei) clade (eastern Caribbean). Divergence between Pholidoscelis and its sister clade was estimated to have occurred ~25 Ma, with subsequent diversification on Caribbean islands occurring over the last 11 Myr. Of the six models compared in the biogeographic analyses, the scenario which considered the distance among islands and allowed dispersal in all directions best fit the data. These reconstructions suggest that the ancestor of this group colonized either Hispaniola or Puerto Rico from Middle America. The authors provide a well-supported phylogeny of Pholidoscelis with novel relationships not reported in previous studies that were based on significantly smaller datasets. They propose that Pholidoscelis colonized the eastern Greater Antilles from Middle America based on our biogeographic analysis, phylogeny, and divergence time estimates. The closing of the Central American Seaway and subsequent formation of the modern Atlantic meridional overturning circulation may have promoted dispersal in this group.

Citation
Tucker DB, Hedges SB, Colli GR, Pyron RA, Sites JW. Genomic timetree and historical biogeography of Caribbean island ameiva lizards (Pholidoscelis: Teiidae). Ecology and Evolution. 2017 Aug.

A frog that cannot hear its own call


Pumpkin toadlets, found in the leaf litter of Brazil's Atlantic forest, are among the smallest frogs in the world.

An international team from Brazil, Denmark, and the United Kingdom, has discovered that two species of these tiny orange frogs cannot hear the sound of their own calls.

This is a unique case in the animal kingdom of a communication signal persisting even after the target audience has lost the ability to detect it.

"We have never seen this before: These frogs make sounds that they cannot hear themselves," says Associate Professor, Jakob Christensen-Dalsgaard, University of Southern Denmark.

He led the laboratory testing of the frogs' hearing abilities at the University of Southern Denmark. The findings have been confirmed by anatomical studies at Cambridge University, UK, showing that the part of the ear responsible for high-frequency hearing is vestigial in these species.

Lead author of the study is Dr. Sandra Goutte, who was postdoc at Universidade Estadual de Campinas, São Paulo, Brazil, when the study was conducted.

Most male frogs call to signal their presence to the opposite sex and find a mate, but this is costly: it could attract predators and parasites, and it uses up energy and time.

"One would think that if a signal is not perceived by its target audience, it would be lost through evolution," says Dr. Sandra Goutte.

Because these tiny frogs are brightly colored, diurnal and known to use visual signals, the researchers hypothesize that visual communication has replaced acoustic communication.

The movement of the throat when males are calling could constitute a visual signal, in which case the call itself would represent a by-product of the true signaling behavior.

Like many brightly-colored tropical frogs, pumpkin toadlets are highly toxic, which may lower the risk of predation when they are calling.

The singular communication system in these pumpkin toadlets is the first example of vestigial sound communication, says Jakob Christensen-Dalsgaard.

Studying the toadlets further will advance our understanding of the mechanisms underlying the evolution of communication systems in animals.

Citation
 Goutte S, Mason MJ, Christensen-Dalsgaard J, Fernando Montealegre-Z F. Chivers BD, Sarria-S FA,  Antoniazzi MM,  Jared C,  Sato LA,  Toledo LF. 2017. Evidence of auditory insensitivity to vocalization frequencies in two frogs. Scientific Reports, 2017; 7 (1) DOI: 10.1038/s41598-017-12145-5

Sunday, May 28, 2017

A new, morphologically cryptic, leaf-nesting frog of the genus Phyllomedusa


Male holotype of Phyllomedusa chaparroi sp. nov. (MUBI 13986) 
Casttoviejo-Fischer and colleagues describe and name the new leaf-nesting frog, Phyllomedusa chaparroi, a medium-sized species (67.9–77.5 mm) from the Amazonian rainforests of northern Peru. Morphologically the new species is most similar to P. boliviana and P. camba, it is indistinguishable from the latter in external qualitative and quantitative traits). However, phylogenetic analysis of combined mitochondrial and nuclear markers place the new species sister to a clade containing P. neildi, P. tarsius, and P. trinitatis. Phyllomedusa chaparroi can be readily differentiated from these species by having a dark reddish-brown iris with indistinct tiny orange spots versus an orange iris with marked dark reticulation found in P. neildi, P. tarsius, and P. trinitatis. Furthermore, the genetic distances for a 532 bp sequence of the 16S gene between the new species and its sister species are 2.8–4.1%, whereas distances are 4.5–5.5% to the morphologically cryptic P. camba. The type series of Phyllomedusa chaparroi includes specimens from two sites, this species seems to occur at various localities in the area of Tarapoto in the Peruvian Amazon. Nonetheless, it seems that this species has been confused with Phyllomedusa camba and the distributional range of both species needs to be thoroughly evaluated, especially at the northern western limits of the known distribution of P. camba.

Citation
Castroviejo-Fisher SA, Köhler J, De La Riva IG, Padial JM.. A new morphologically cryptic species of Phyllomedusa (Anura: Phyllomedusidae) from Amazonian forests of northern Peru revealed by DNA sequences. Zootaxa. 2017 May 22;4269(2):245-64.


Saturday, May 27, 2017

Brazilian microteiids - and the increase of Brazilian lizard species since 1995

Gymnophthalmus underwoodi, a widespread all-female species.
In a new paper, Ribeiro-Junior and Amaral present distribution data of all Alopoglossidae and Gymnophthalmidae lizards known from the Brazilian Amazonia. The paper presents a total of 54 species-level taxa, belonging to 17 genera and two families. This represents 22 more species-level taxa than previously reported. The results  were based on the examination of 17,431 specimens deposited in three North American and eight Brazilian museums, including the main collections harboring Amazonian material. Most species (~80%) are endemic to Amazonia; non-endemic species are mainly associated with open vegetation (savanna) enclaves or open dry (semi-deciduous) forest in Amazonia, with a few exceptions. As a whole, seven taxa (including one species complex) are widespread in Amazonia, six are restricted to eastern Amazonia, seven to western Amazonia, two to southwestern Amazonia, 11 to southern Amazonia, 11 to northern Amazonia (either in part of it or widespread in the Guiana region), and six to the southern peripheral portion of Amazonia. Besides, four species present unique distributions. Considering this study and the other three catalogues of distribution of lizards already published, the total number of lizard species from Brazilian Amazonia increased from 97 to 142 species-level taxa. This represents an increase of 45 species from the region since the last revision in 1995.

Citation
Ribeiro-Junior MA, Amaral S. 2017. Catalogue of distribution of lizards (Reptilia: Squamata) from the Brazilian Amazonia. III. Anguidae, Scincidae, Teiidae. Zootaxa. 2016 Dec 9;4205(5):401-30.

Do not publish


David Lindenmayer, Ben Scheele
Science  26 May 2017:Vol. 356, Issue 6340, pp. 800-801DOI: 10.1126/science.aan1362

Biologists have long valued publishing detailed information on rare and endangered species. Until relatively recently, much of this information was accessible only through accessing specialized scientific journals in university libraries. However, much of these data have been transferred online with the advent of digital platforms and a rapid push to open-access publication. Information is increasingly also available online in public reports and wildlife atlases, and research published behind paywalls can often be found in the public domain. Increased data and information accessibility has many benefits, such as helping to improve repeatability in scientific studies and enhancing collaboration (1, 2). However, such readily accessible information also creates major problems in the context of conserving endangered species.

Increasingly, the dual-use research dilemma (3), in which research can have both substantial positive but also negative impacts, is pervading research on rare and endangered species, with information intended to aid conservation fueling illegal actions that harm biodiversity. Biologists must urgently unlearn parts of their centuries-old publishing culture and rethink the benefits of publishing location data and habitat descriptions for rare and endangered species to avoid unwittingly contributing to further species declines. Restricting information entails some costs, but these must be weighed against the increasing harm of unrestricted information accessibility.

At least three key issues associated with unrestricted access to information on rare and endangered species warrant careful attention. These risks are not new but are greatly exacerbated in an era of digital proliferation and open access. First, unrestricted access to species location information is facilitating a surge in wildlife poaching (4, 5), with many species at risk (6). Poaching has been documented in species within months of their taxonomic description in journals (4). For example, more than 20 newly described reptile species have been targeted in this way, potentially leading to extinction in the wild. Indeed, when the names of some of these species—such as the Chinese cave gecko, Goniurosaurus luii (see the photo)—are typed into a search engine, the text autopopulates to suggest a search to purchase these animals.

Second, unrestricted access to location data and habitat descriptions can disrupt the often delicate relationships between scientists and landowners. We have personal experience of this. Our research in Australia on restoring farmland biodiversity requires repeated access to farms and depends on high levels of trust among landholders. We have detected populations of endangered species such as the pink-tailed worm-lizard (Aprasia parapulchella). Our research permits demand that location records be uploaded to open-access government wildlife atlases. Soon after uploading records, people seeking the rare worm-lizard were caught trespassing, upsetting farmers, damaging important rocky outcrop habitats, and jeopardizing scientist-farmer relationships that have taken years to establish.

Third, unrestricted access to species information has the potential to accelerate habitat destruction and create other negative disturbances. The digital age has brought a desire among many nature enthusiasts to observe, photograph, and sometimes remove animals and plants (7). Animal behavior and habitats are often heavily disturbed in the process (8).

Decisions to publish sensitive information on endangered and newly described rare species must be based around a careful assessment of whether its publication will benefit or harm the target species (see the figure). Key trade-offs must be weighed. For example, easily accessible data can help amass the evidence to challenge development proposals that may affect endangered species. Increased data accessibility can also foster improved scientific repeatability and greater collaboration. Although withholding information may have some negative consequences, this action is increasingly needed (9), given that calls for better regulation and law enforcement to protect atrisk species have met limited success (4, 5).

Where species have high economic value (such as in the case of the Chinese cave gecko), withholding information may be the only option. Relevant government or regulatory agencies should be notified of scientific discoveries, and pathways for access from legitimate persons remain open. In moderate risk situations, spatial data might be buffered and only very broad location data provided. Where there is low risk of perverse outcomes, unrestricted publication of habitat descriptions and location information remains appropriate (see the figure).

Much information on endangered and newly described species can still be published without location data being provided and without undermining the integrity or repeatability of the scientific work [akin to the notion that the rediscovery of Lazarus species can be validated without the collection of voucher specimens (10)]. As such, negative trade-offs arising from the dual-use research dilemma are not as pronounced as in other fields. For example, restrictions on publishing methodological advances in the study of pathogen virulence can inhibit scientific research that can have considerable human health benefits but is sometimes deemed necessary because of the potential for this information to facilitate perverse outcomes (such as bioterrorism) (11, 12).

Endangered or newly discovered species can be at risk from poachers if their location data is published. This scheme helps to assess whether publication should be restricted in particular cases.

Some fields such as paleontology and archaeology have long maintained restrictions on the publication of site locations and promoted government policies and regulations to limit collection and trade in fossils, artefacts, and culturally sensitive and/or scientifically important material (13). Organizations such as the U.S. Forest Service do not disclose geospatial data in order to protect research sites (14). Other solutions include modification of research permits so that endangered species locations are not automatically uploaded into wildlife databases and masking such records on private land, as presently occurs in some states in the United States. Some of these approaches are already in place in conservation; for example, the open-access journal PLOS ONE has data exemptions for endangered species. However, current policies are specific to individual journals, data repositories, or organizations and lack consistent enforcement. A major benefit to the author-led self-censorship that we advocate is that restrictions of the dissemination of sensitive information can be implemented widely and immediately.

There are signs that this problem is beginning to be addressed. Journals such as Zootaxa that carry taxonomic descriptions of new species now publish new descriptions without location information (15). More researchers, journal editors, and data custodians need to follow their lead. Otherwise, the potential benefits of open-access scientific information and data for biodiversity conservation will be outweighed by the perverse effects of exposing wild populations to substantial added conservation threats. Although much information on endangered and rare species is already available online, it remains crucial to change our actions now to avoid unwittingly contributing to further species declines.