Saturday, March 30, 2013

[Ichthyology • 2013] Re-description of Arapaima agassizii (Valenciennes), a Rare Fish from Brazil (Osteoglossomorpha: Osteoglossidae)

The bony-tongue fish genus Arapaima Müller has been considered monotypic since 1868, with A. gigas being the only recognized species. Review of species-level taxonomy of Arapaima has revealed that Arapaima agassizii Valenciennes (in Cuvier and Valenciennes, 1847) should be considered a valid species. The holotype was destroyed in World War II, but the species can be recognized based on the original description, which included detailed osteological illustrations. At least nine characters distinguish it from all other Arapaima: 1) dentary teeth 44 (counted on one ramus only, vs. 21–37 in other Arapaima); 2) maxillary teeth 43 (vs. 21–38 in other Arapaima); 3) orbit diameter 1.5% standard length (SL, vs. 1.5–2.8, relatively larger in all other Arapaima at similar SL); 4) interorbital width 4.1% SL (vs. 5.3–6.5 in other Arapaima); 5) parietals with pronounced posterior projections that are pointed and curve slightly toward midline (vs. absent in other Arapaima); 6) caudal fin widely separated from dorsal and anal fins by long caudal peduncle, 9.7% SL (vs. much shorter peduncle, 3.2–5.5 in others); 7) anal fin with only 26 rays (vs. 30–40 in others), with distinctly shorter basal length than dorsal-fin base; 8) dorsal and anal fins extremely low in profile; dorsal-fin base divided by longest dorsal ray about 7 (vs. 3.1–5.5 in others); and 9) first pectoral-fin ray with proximal tip similar in form to subsequent pectoral-fin rays (vs. first pectoral-fin ray noticeably enlarged relative to subsequent rays). Arapaima agassizii still is known only from the holotype, which was collected in 1817–20 somewhere in lowlands of the Brazilian Amazon. It thus is important to locate this taxon to determine its distribution and conservation status.

Stewart, D.J. 2013. Re-description of Arapaima agassizii (Valenciennes), a Rare Fish from Brazil (Osteoglossomorpha: Osteoglossidae). Copeia. 2013 (1) : 38-51.

Friday, March 29, 2013

[Mammalogy • Extinct] Africa's Western Black Rhinoceros Diceros bicornis longipes declared Extinct

Africa's Western Black Rhinoceros Diceros bicornis longipes declared extinct
| Quarter of all mammals at risk of extinction, group says; Northern White Rhino of central Africa also now 'possibly extinct' in the wild
— The Western Black Rhino of Africa was declared officially extinct Thursday by a leading conservation group.

The International Union for Conservation of Nature said that two other subspecies of rhinoceros were close to meeting the same fate. The Northern White Rhino of central Africa is now "possibly extinct" in the wild and the Javan Rhino "probably extinct" in Vietnam, after poachers killed the last animal there in 2010. A small but declining population survives on the Indonesian island of Java.

IUCN said Thursday that a quarter of all mammals are at risk of extinction, according to its updated Red List of endangered species.


[Paleontology • 2013] European origin of placodont marine reptiles and the evolution of crushing dentition in Placodontia | Fossil Placodont Discovered In Netherlands

Reconstruction of the juvenile placodont Palatodonta bleekeri. The teeth are striking compared to other placodonts.
(picture: Rekonstruktionszeichnung: Jaime Chirinos)

 Sauropterygia was the most successful marine reptile radiation in history, spanning almost the entire Mesozoic and exploiting a wide range of habitats and ecological niches. Here we report a new, exceptionally preserved skull of a juvenile stem placodont from the early Middle Triassic of the Netherlands, thus indicating a western Tethyan (European) origin for Placodontia, the most basal group of sauropterygians. A single row of teeth on an enlarged palatine supports this close relationship, although these are small and pointed instead of broad and flat, as is the case in placodonts, which demonstrate the strongest adaptation to a durophagous diet known in any reptile. Peg-like, slightly procumbent premaxillary teeth and an ‘L-shaped’ jugal also confirm a close relationship to basal placodonts. The new taxon provides insight into the evolution of placodont dentition, representing a transitional morphology between the plesiomorphic diapsid condition of palatal denticles and the specialized crushing teeth of placodonts.

Subject terms: Biological sciences, Evolution, Palaeontology

The recently discovered skull of a juvenile placodont from Winterswijk, the Netherlands.
 (picture: UZH)

The placodonts are fellow Europeans
Placodonts were among the first marine reptiles. With their trademark crushing teeth, they fed on shellfish and crustaceans. However, when and where these highly specialized marine reptiles originated remained unclear until now. A 246-million-year-old skull of a juvenile placodont was recently discovered in the Netherlands. Paleontologists from the universities of Zurich and Bonn have now proved that it is one of the earliest examples of this saurians and that it originated in Europe.

For around 50 million years, placodonts populated the flat coastal regions of the Tethys Ocean, in modern day Europe and China. The most distinctive feature of these dinosaurs was their teeth: The upper jaw had two rows of flattened teeth – one on the palate and one on the jawbone – while the lower jaw only had one set of teeth ideal for crushing shellfish and crustaceans.

The evolutionary origins of these placodonts remained unclear. However, a new find in a 246-million-year-old sediment layer now sheds light on the origin and phylogenetic development of the placodonts. As the Swiss and German team headed by Torsten Scheyer, a paleontologist at the University of Zurich, reveals the skull found in Winterswijk (Netherlands) is the earliest form of all known placodonts. The juvenile animal lived 246 million years ago. At around two centimeters in size, the skull is exceptionally well preserved and its characteristics set it apart from previous placodont discoveries.

Double row of pointed teeth
The basal-most known placodonts to date have the group’s trademark double row of crushing teeth in the upper jaw. The flattened teeth that give these animals their name only appear in more derived placodonts. “Unlike all the other placodonts discovered to date, the Winterswijk specimen has conical, pointed teeth instead of flattened or ball-shaped crushing ones,” explains Scheyer, “which means the pointed teeth on the lower jaw slotted precisely into the gap between the palate and upper-jawbone teeth when biting.”

The group’s trademark double row of teeth in the upper jaw is proof that the new find is actually a placodont. According to the researchers, the teeth of Palatodonta bleekeri, the scientific name given to the Winterswijk specimen, were specialized in gripping and piercing soft prey. “The double row of teeth in the new find combined with its considerable age lead us to conclude that it is a very early placodont, from which the later forms developed,” says Scheyer. The formation of crushing teeth and the specialization of a diet of shellfish and crustaceans thus developed later within placodont evolution.

European origin confirmed
The small Palatodonta bleekeri skull sheds new light on the ongoing debate on where the placodonts originated: Previous finds suggested origins in the shelf sea areas of either present-day China or Europe. Due to the considerable age of the new Dutch find and its basal form, however, the European origin of the placodonts is deemed confirmed. Scheyer and his colleagues are hoping for further exciting finds in Winterswijk to discover more about the evolution of the placodonts.

James M. Neenan, Nicole Klein, Torsten M. Scheyer. 2013. European origin of placodont marine reptiles and the evolution of crushing dentition in Placodontia. Nature Communications. March 27, 2013. doi: 10.1038/ncomms2633

Thursday, March 28, 2013

[Primatology • 2012] A Genome Sequence Resource for the Aye-Aye Daubentonia madagascariensis, a Nocturnal Lemur from Madagascar

Aye-aye Daubentonia madagascariensis species distribution in Madagascar and extractive foraging behavior
photo: Francois Randrianasolo

Aye ayes have the largest brain to body ratio, making them the smartest lemurs. Humans often kill them on sight because the animals are considered a bad omen.
photo: Edward Louis 

We present a high-coverage draft genome assembly of the aye-aye (Daubentonia madagascariensis), a highly unusual nocturnal primate from Madagascar. Our assembly totals ;3.0 billion bp (3.0 Gb), roughly the size of the human genome, comprised of ;2.6 million scaffolds (N50 scaffold size 5 13,597 bp) based on short paired-end sequencing reads. We compared the aye-aye genome sequence data with four other published primate genomes (human, chimpanzee, orangutan, and rhesus macaque) as well as with the mouse and dog genomes as nonprimate outgroups. Unexpectedly, we observed strong evidence for a relatively slow substitution rate in the aye-aye lineage compared with these and other primates. In fact, the aye-aye branch length is estimated to be ;10% shorter than that of the human lineage, which is known for its low substitution rate. This finding may be explained, in part, by the protracted aye-aye life-history pattern, including late weaning and age of first reproduction relative to other lemurs. Additionally, the availability of this draft lemur genome sequence allowed us to polarize nucleotide and protein sequence changes to the ancestral primate lineage—a critical period in primate evolution, for which the relevant fossil record is sparse. Finally, we identified 293,800 high-confidence single nucleotide polymorphisms in the donor individual for our aye-aye genome sequence, a captive-born individual from two wild-born parents. The resulting heterozygosity estimate of 0.051% is the lowest of any primate studied to date, which is understandable considering the aye-aye’s extensive home-range size and relatively low population densities. Yet this level of genetic diversity also suggests that conservation efforts benefiting this unusual species should be prioritized, especially in the face of the accelerating degradation and fragmentation of Madagascar’s forests.

Key words: genome assembly, molecular clock, primate evolution, lemur.

Aye-aye Daubentonia madagascariensis species distribution in Madagascar and extractive foraging behavior
photo: Francois Randrianasolo

An aye aye, a type of lemur, lives in Madagascar. A new study highlights genetic diversity among various populations, aiding conservation of the endangered species.
photo: Edward Louis

George H. Perry, Darryl Reeves, Pa´ll Melsted, Aakrosh Ratan, Webb Miller, Katelyn Michelini,
Edward E. Louis Jr, Jonathan K. Pritchard, Christopher E. Mason, and Yoav Gilad1. 2012. A Genome Sequence Resource for the Aye-Aye (Daubentonia madagascariensis), a Nocturnal Lemur from Madagascar. Genome Biology and Evolution. 4 (2): 126-135. doi: 10.1093/gbe/evr132

Aye aye! Sequence genomes to save species

Wednesday, March 27, 2013

[Primatology • 2013] Microcebus marohita & M. tanosi | Two New Species of Mouse Lemurs (Cheirogaleidae: Microcebus) from Eastern Madagascar

Caught on camera for the first time, the newly identified Marohita mouse lemur Microcebus marohita.
photo: Peter Kappeler

The number of newly discovered Malagasy vertebrate taxa has multiplied in recent years, emphasizing the importance of complete taxon sampling for phylogenetics, biogeography, functional ecology, and conservation biology, especially in such a biodiversity hotspot. In particular, the diversity of extant lemurs is much higher than previously thought, and we have yet to comprehend fully the full extent of lemuriform biodiversity. A recent genetic analysis of mtDNA and nDNA sequence data in Malagasy mouse lemurs revealed the existence of several novel mtDNA clades based on new field sampling. These geographically defined and previously unrecognized mtDNA clades corresponded precisely to patterns of population structure revealed in the analysis of the nDNA data, thus confirming their evolutionary divergence from other mouse lemur clades. Two of these independently evolving lineages correspond to specimens that were collected by us in the Marolambo and Manantantely/Ivorona regions. Here we summarize the genetic evidence and report on the morphometric and external characteristics of these animals, formally describing them as new species. This report thus brings the number of currently recognized and described mouse lemur species to 20. The forests in which these mouse lemurs were discovered have been heavily degraded in the past decade, prompting the classification of one of the new species as Endangered by the IUCN, even before its formal description. As with several other newly described lemur species, immediate field studies and appropriate conservation actions are therefore urgent.

Keywords: Biodiversity, Taxonomy, Madagascar, Microcebus, Mouse lemurs

Marohita mouse lemur Microcebus marohita


2 'giant' yet tiny mouse lemurs identified in Madagascar 

Scientists have discovered two new species of mouse lemurs in Madagascar, bringing the total number of diminutive primates known to science to 20, according to a paper published in the latest issue of the International Journal of Primatology.

The lemurs were collected in 2003 and 2007 during field surveys to the eastern part of the island nation. Genetic analysis revealed them to be new species: the Marohita mouse lemur (Microcebus marohita) and the Anosy mouse lemur (Microcebus tanosi).

Both species are unusually large for mouse lemurs. Microcebus marohita tips the scales at 78 grams (2.8 ounces), making it the largest of the known mouse lemur. It reaches a length of 28 cm. Microcebus tanosi is now the second largest known mouse lemur, reaching 27 cm from snout to tail and weighing about 50 grams. It is named after the Anosy region in southeast Madagascar.


2 'giant' yet tiny mouse lemurs identified in Madagascar 

Two new species of mouse lemur found in Madagascar

Rodin M. Rasoloarison, David W. Weisrock, Anne D. Yoder, Daniel Rakotondravony, Peter M. Kappeler. 2013. Two New Species of Mouse Lemurs (Cheirogaleidae: Microcebus) from Eastern Madagascar. International Journal of Primatology, DOI:  10.1007/s10764-013-9672-1

[Herpetology • 2012] Rediscovery of Geckoella jeyporensis (Squamata: Gekkonidae) in the Eastern Ghats, in Orissa and Andhra Pradesh, India | with notes on morphology, coloration and habitat

Geckoella jeyporensis - Rediscovered after 135 years from Odisha and Andhra Pradesh

For over a century and quarter, the tiny Geckoella jeyporensis, a small lizard measuring up to 10 cm, was given up as extinct. Now it has been spotted in the Eastern Ghats, causing scientists to cheer. A dedicated and concerted effort by a group of environmentalists has caused the rediscovery of the Geckoella jeyporensis in the Eastern Ghats, in Orissa and Andhra Pradesh. The lizard has not been seen in 135 years, a scientist involved in the efforts revealed.

"This gecko, a lizard of the Gekkonidae family, is morphologically unique. It was known only from a single male specimen collected in 1877 by a British officer, Col R.H. Beddome, from the Jeypore Hills, in modern Orissa," Varad Giri, a scientist with the Bombay Natural History Society (BNHS), told IANS.

The "re-discovery" of this species was the result of a joint venture between the Centre for Ecological Sciences of the Indian Institute of Science (CES-IISc), Bangalore, BNHS Mumbai and Villanova University, US. The journal Hamadryad has endorsed the rediscovery.

The efforts were propelled by the research of CES-IISc doctoral student Ishan Agarwal, who in 2008-2009 wanted to find this lost species to understand its evolutionary history. There was scanty published material around this particular lizard, and an attempt was made to retrace the journey Col Beddome undertook in the Eastern Ghats over a century ago.

"The only clues were in the original description, which said that this species was collected under a rock in a forest at 4,200 ft on 'Patinghe Hill, Jeypore' - meaning high elevation forest areas (@1,000m) in the Eastern Ghats," Agarwal told IANS.

Teams of researchers, scientists and naturalists had failed in the past 135 years to trace the unique lizard, Agarwal said. As he grew convinced that the gecko could be found again, another doctoral student, Aniruddha Datta-Roy, and field assistant Tarun Khichi, also joined him on the uncertain mission.

"It takes persistence and just a little bit of luck. So, it was that one day of hard work by four of us which paid off in a spectacular fashion - the unexpected rediscovery of Geckoella jeyporensis!", Agarwal said.

This was a significant addition to the 190 species of lizards currently known to exist in India, Giri explained.After one effort yielded nothing, the team tried its luck again in 2011. This time, it hit bull's eye in Andhra Pradesh. After the exciting discoveries, Giri and Aaron Bauer of Villanova University, US, studied the taxonomy of the species and it was subsequently confirmed as a "rediscovery".

"This species is unique among Indian geckos as it has enlarged, hexagonal, plate-like scales across the back. It is one of the most beautiful among Indian geckos, with an orange-brown dorsum, a series of large chocolate brown dorsal blotches," Giri said.

Giri and Agarwal said that besides being morphologically unique and endemic to a region not traditionally known to harbour many endemics, this species appears restricted to a very specialised habitat in the Eastern Ghats, semi-evergreen forests above 1,000 m elevation.

"This discovery leads us to conclude that the country's Eastern Ghats are more biodiverse than previously believed. There is a strong need for the authorities concerned to protect the region, its flora and fauna," Giri urged.

"In many ways, the rediscovery of Geckoella Jeyporensis is symptomatic of herpetological research in India. There are a number of species that have not been recorded since their original descriptions or are known in a few localities," said the study by Hamadryad.

Geckoella jeyporensis - Rediscovered after 135 years from Odisha and Andhra Pradesh

Agarwal, Ishan, Aniruddha Datta-Roy, Aaron M. Bauer and Varad B. Giri. 2012. Rediscovery of Geckoella jeyporensis (Squamata: Gekkonidae), with notes on morphology, coloration and habitat. Hamadryad. 36 (1): 17-24

Lizard Species Rediscovered After 135 Years

Monday, March 25, 2013

[Ornithology • 1999] Glaucidium nubicola | Cloud-forest Pygmy-Owl • A new species of Pygmy-owl (Strigidae: Glaucidium) from the Pacific slope of the Northern Andes

Cloud-forest Pygmy-Owl Glaucidium nubicola 
painting Tracy Pedersen |

We describe a new species of pygmy-owl that is restricted to very wet cloud forest at 1,400 to 2,000 m in elevation along the Pacific slope of the western Andes of Colombia and Ecuador. This taxon had been long overlooked as a result of its morphological similarity and geographic proximity to the Andean Pygmy-Owl (Glaucidium jardinii), but it is vocally very distinct and exhibits subtle but consistent morphological differences as well. Vocally, the new species is most similar to the Costa Rican-Panamanian form G. costaricanum and to the nominate subspecies of Northern Pygmy-Owl (G. gnoma), but again, consistent differences exist in vocalizations and morphology. Glaucidium costaricanum has long been considered a subspecies of G. jardinii, but at least one recent author treated it as a subspecies of G. gnoma. Genetic, vocal, ecological, and morphological data indicate that G. costaricanum should be elevated to species level, and it along with the new species are considered allospecies within the Northern Pygmy-Owl superspecies complex. 

Cloud-forest Pygmy-Owl Glaucidium nubicola 

Distribution: western Colombia; western Ecuador: wet cloud forests of western Andes between 1400-2000 m

Robbins, M. B. & F. G. Stiles. 1999. A new species of Pygmy-owl (Strigidae: Glaucidium) from the Pacific slope of the Northern Andes. The Auk. 116: 305-315.

2003. Notes on the distribution, habitat and conservation of the Cloud-forest Pygmy-Owl (Glaucidium nubicola) in Ecuador. Ornitologia Neotropical 14: 275-278.
2010. Nuevo registro del Buhito nubícola (Glaucidium nubicola) en la cordillera Occidental de Colombia

[Ornithology • 2012] Geodatabase of Global Owl species and Owl Biodiversity Analysis

Global diversity assessments contribute to the understanding of large taxonomic groups, and conservation efforts depend on knowledge of taxonomic status, distribution and abundance of species. These assessments and databases provide a basis for studying patterns and changes in species distribution and diversity, especially in light of global issues such as climate change. As apex predators, owls can play a significant role in providing for broader ecosystem-level conservation and analysis. Because they are excellent indicators of biodiversity and ecosystem health, owls can be used to identify conservation targets and at-risk areas. By studying and conserving owl species, larger biodiversity conservation goals can be achieved. This project developed a geodatabase of 211 owl species range maps and analyzed the characteristics of the global distribution of owlsfor the Global Owl Project (GLOW). Density maps of species richness, threatened species, data deficient species, and restricted-range species were developed using the database. A rarity-weighted species index using the parameters of the threatened and restricted-range species revealed conservation priority areas in South America, central Africa, and Indonesia. 

Keywords: owl, biodiversity, GIS, database, range maps

Figure 3. The global distribution of 210 of the 221 owl species identified by the International Ornithological Union. 

Cite as: Romulo, Chelsie L. 2012. Geodatabase of global owl species and owl biodiversity analysis. Master of Natural Resources Capstone Paper. Virginia Polytechnic Institute and State University, Falls Church, Virginia. 53 pp.

Sunday, March 24, 2013

[Herpetology • 2011] A Biogeographic Synthesis of the Amphibians and Reptiles of Indochina


Indochina (Laos, Cambodia, and Vietnam) houses over 600 species of amphibians and reptiles, roughly a quarter of which has been described within the last 15 years. Herein, we undertake the first biogeographic synthesis of the regional herpetofauna since the first half of the 20th century. We review the literature to measure and map species richness and endemism, the contributions of regional faunas, and ecological characteristics of Indochina’s amphibians (Anura, Caudata), and reptiles (Serpentes, Sauria, Testudines, Crocodylia). Dividing Indochina into 19 subregions defined by topography and geology, we estimate the similarity among the regional faunas and appraise the effects of area and survey effort on these comparative analyses.

Variation in species composition is broadly correlated with topography, habitat complexity, and proximity to regions outside Indochina. Indochina’s herpetofauna is dominated (in decreasing order) by endemic species, widely distributed species, a South China fauna, and a biota centered in Thailand and Myanmar. Species richness is highest in amphibians and snakes, and peaks in upland forests. Endemism, highest among amphibians and lizards, also peaks in forests of the region’s northern uplands and Annamite Range. Endemic species occupy a narrower range of habitats than nonendemics. Patterns of richness and endemism are partially explained by ecological constraints: amphibians and lizards are more restricted to forests than snakes, turtles, and crocodiles; amphibians are more restricted to uplands, turtles to lowlands.

We also assess biogeography in the context of Indochina’s geology, climate, and land cover. In northern Indochina, the Red River either acts as or coincides with an apparent dispersal barrier. Herpetofauna in northeastern upland areas are closely allied with fauna of southeastern China. In southern Indochina there is little evidence that the Mekong River represents a biogeographic barrier to the regional herpetofauna. The Annamite Range is composed of at least three distinct units and its elevated species richness and endemism are also noted in adjacent lowlands. Contribution of subtropical biota to Indochina’s fauna is significantly greater than that of tropical biota and there is little other evidence for intermixing at intermediate latitudes.

Our results have implications for biogeography and conservation efforts, although they must be viewed in the context of rapidly evolving systematic knowledge of the region’s amphibians and reptiles. Future survey efforts, and the phylogenetic analyses that come from them, are essential for supporting regional conservation efforts, as they will better resolve the known patterns of amphibian and reptile richness and endemism.


Raoul H. Bain and Martha M. Hurley. 2011. A Biogeographic Synthesis of the Amphibians and Reptiles of Indochina. Bulletin of the American Museum of Natural History (Nov 2011): 1-138.

[Entomology • 2013] Mimetic host shifts in an endangered social parasite of ants | the Taxonomic Implications of Host Preference in Large Blue Butterflies

The life cycle of Large Blue Butterflies Maculinea rebeli


An emerging problem in conservation is whether listed morpho-species with broad distributions, yet specialized lifestyles, consist of more than one cryptic species or functionally distinct forms that have different ecological requirements. We describe extreme regional divergence within an iconic endangered butterfly, whose socially parasitic young stages use non-visual, non-tactile cues to infiltrate and supplant the brood in ant societies. Although indistinguishable morphologically or when using current mitochondrial and nuclear sequence-, or microsatellite data, Maculinea rebeli from Spain and southeast Poland exploit different Myrmica ant species and experience 100 per cent mortality with each other's hosts. This reflects major differences in the hydrocarbons synthesized from each region by the larvae, which so closely mimic the recognition profiles of their respective hosts that nurse ants afford each parasite a social status above that of their own kin larvae. The two host ants occupy separate niches within grassland; thus, conservation management must differ in each region. Similar cryptic differentiation may be common, yet equally hard to detect, among the approximately 10 000 unstudied morpho-species of social parasite that are estimated to exist, many of which are Red Data Book listed.

Keywords: chemical mimicry, host specificity, butterfly, conservation, Maculinea, Phengaris

Thomas JA, Elmes GW, Sielezniew M, Stankiewicz-Fiedurek A, Simcox DJ, Settele J, Schoenrogge K. 2013. Mimetic host shifts in an endangered social parasite of ants. Proc R Soc B 280: 20122336.

The Taxonomic Implications of Host Preference in Large Blue Butterflies

[Geology • 2013] Melt-rich channel observed at the lithosphere–asthenosphere boundary | Hidden magma layer: Scientists discover 'Lubricant' for Earth's tectonic plates

Map of the 2010 survey region

The lithosphere–asthenosphere boundary (LAB) separates rigid oceanic plates from the underlying warm ductile asthenosphere. Although a viscosity decrease beneath this boundary is essential for plate tectonics, a consensus on its origin remains elusive. Seismic studies identify a prominent velocity discontinuity at depths thought to coincide with the LAB but disagree on its cause, generally invoking either partial melting or a mantle dehydration boundary as explanations. Here we use sea-floor magnetotelluric data to image the electrical conductivity of the LAB beneath the edge of the Cocos plate at the Middle America trench offshore of Nicaragua. Underneath the resistive oceanic lithosphere, the magnetotelluric data reveal a high-conductivity layer confined to depths of 45 to 70 kilometres. Because partial melts are stable at these depths in a warm damp mantle, we interpret the conductor to be a partially molten layer capped by an impermeable frozen lid that is the base of the lithosphere. A conductivity anisotropy parallel to plate motion indicates that this melt has been sheared into flow-aligned tube-like structures. We infer that the LAB beneath young plates consists of a thin, partially molten, channel of low viscosity that acts to decouple the overlying brittle lithosphere from the deeper convecting mantle. Because this boundary layer has the potential to behave as a lubricant to plate motion, its proximity to the trench may have implications for subduction dynamics.

Subject terms: Tectonics, Geodynamics


Scripps Scientists Discover ‘Lubricant’ for Earth’s Tectonic Plates
Hidden magma layer could play a role in earthquakes and other aspects shaping the geological face of the planet

Scientists at Scripps Institution of Oceanography at UC San Diego have found a layer of liquefied molten rock in Earth’s mantle that may be acting as a lubricant for the sliding motions of the planet’s massive tectonic plates. The discovery may carry far-reaching implications, from solving basic geological functions of the planet to a better understanding of volcanism and earthquakes.

The scientists discovered the magma layer at the Middle America trench offshore Nicaragua. Using advanced seafloor electromagnetic imaging technology pioneered at Scripps, the scientists imaged a 25-kilometer- (15.5-mile-) thick layer of partially melted mantle rock below the edge of the Cocos plate where it moves underneath Central America.

The discovery is reported in the March 21 issue of the journal Nature by Samer Naif, Kerry Key, and Steven Constable of Scripps, and Rob Evans of Woods Hole Oceanographic Institution.

The new images of magma were captured during a 2010 expedition aboard the U.S. Navy-owned and Scripps-operated research vessel Melville. After deploying a vast array of seafloor instruments that recorded natural electromagnetic signals to map features of the crust and mantle, the scientists realized they found magma in a surprising place.

“This was completely unexpected,” said Key, an associate research geophysicist in the Cecil H. and Ida M. Green Institute of Geophysics and Planetary Physics at Scripps. “We went out looking to get an idea of how fluids are interacting with plate subduction, but we discovered a melt layer we weren’t expecting to find at all—it was pretty surprising.”

The orange colored area enclosed by a dashed line denotes a magma layer that scientists believe is facilitating the motion of the Cocos plate off Nicaragua. The blue areas represent the Cocos plate sliding across the mantle and eventually diving beneath the Central American continent, while the black dots signify earthquake locations. The discovery was made by analyzing data collected by an array of seafloor electromagnetic instruments, shown as inverted triangles.

For decades scientists have debated the forces and circumstances that allow the planet’s tectonic plates to slide across the earth’s mantle. Studies have shown that dissolved water in mantle minerals results in a more ductile mantle that would facilitate tectonic plate motions, but for many years clear images and data required to confirm or deny this idea were lacking.

“Our data tell us that water can’t accommodate the features we are seeing,” said Naif, a Scripps graduate student and lead author of the paper. “The information from the new images confirms the idea that there needs to be some amount of melt in the upper mantle and that’s really what’s creating this ductile behavior for plates to slide.”

The marine electromagnetic technology employed in the study was originated by Charles “Chip” Cox, an emeritus professor of oceanography at Scripps, and in recent years further advanced by Constable and Key. Since 2000 they have been working with the energy industry to apply this technology to map offshore oil and gas reservoirs.

The researchers say their results will help geologists better understand the structure of the tectonic plate boundary and how that impacts earthquakes and volcanism.

“One of the longer-term implications of our results is that we are going to understand more about the plate boundary, which could lead to a better understanding of earthquakes,” said Key.

The researchers are now seeking to find the source that supplies the magma in the newly discovered layer.

The National Science Foundation and the Seafloor Electromagnetic Methods Consortium at Scripps supported the research.

Hidden magma layer: Scientists discover 'Lubricant' for Earth's tectonic plates 
 — Scientists at Scripps Institution of Oceanography at UC San Diego have found a layer of liquefied molten rock in Earth's mantle that may be acting as a lubricant for the sliding motions of the planet's massive tectonic plates. The discovery may carry far-reaching implications, from solving basic geological functions of the planet to a better understanding of volcanism and earthquakes.

S. Naif, K. Key, S. Constable & R. L. Evans. 2013. Melt-rich channel observed at the lithosphere–asthenosphere boundary. Nature. 495, 356–359 (21 March 2013) doi:10.1038/nature11939

[Conference • 2013] Celebrating Dinosaur Island: A Jehol-Wealden International Conference @ the Isle of Wight

The image on the poster is a reconstruction of the skull of Neovenator salerii, a theropod dinosaur unique to the Isle of Wight.

Celebrating Dinosaur Island
 20 - 21 September 2013
Jehol-Wealden International Conference

The Isle of Wight (Dinosaur Island) and China are key areas for Cretaceous fossils, especially dinosaurs. Join us in September 2013 to celebrate this connection at a two day conference hosted by the University of Southampton.

Chinese and UK dinosaur palaeontologists will discuss their research at the National Oceanography Centre, Southampton. Visit key dinosaur sites on the Isle of Wight and network with tourism and business leaders. Build connections for future palaentological research.

Two-day conference hosted by the University of Southampton Confucius Institute and Ocean and Earth Science with support from the National Oceanography Centre, Southampton, the Isle of Wight Visitor Attraction Association and Dinosaur Isle Museum, Sandown.

Friday, March 22, 2013

[Paleontology • 2013] Vectidraco daisymorrisae | ‘dragon from the Isle of Wight’ • A New Small-Bodied Azhdarchoid Pterosaur from the Lower Cretaceous of England and Its Implications for Pterosaur Anatomy, Diversity and Phylogeny

Life reconstruction of Vectidraco daisymorrisae in flight


Pterosaurs have been known from the Cretaceous sediments of the Isle of Wight (southern England, United Kingdom) since 1870. We describe the three-dimensional pelvic girdle and associated vertebrae of a small near-adult pterodactyloid from the Atherfield Clay Formation (lower Aptian, Lower Cretaceous). Despite acknowledged variation in the pterosaur pelvis, previous studies have not adequately sampled or incorporated pelvic characters into phylogenetic analyses.

Methodology/Principal Findings
The new specimen represents the new taxon Vectidraco daisymorrisae gen. et sp. nov., diagnosed by the presence of a concavity posterodorsal to the acetabulum and the form of its postacetabular process on the ilium. Several characters suggest that Vectidraco belongs to Azhdarchoidea. We constructed a pelvis-only phylogenetic analysis to test whether the pterosaur pelvis carries a useful phylogenetic signal. Resolution in recovered trees was poor, but they approximately matched trees recovered from analyses of total evidence. We also added Vectidraco and our pelvic characters to an existing total-evidence matrix for pterosaurs. Both analyses recovered Vectidraco within Azhdarchoidea.

The Lower Cretaceous strata of western Europe have yielded members of several pterosaur lineages, but Aptian pterosaurs from western Europe are rare. With a pelvis length of 40 mm, the new animal would have had a total length of c. 350 mm, and a wingspan of c. 750 mm. Barremian and Aptian pterodactyloids from western Europe show that small-bodied azhdarchoids lived alongside ornithocheirids and istiodactylids. This assemblage is similar in terms of which lineages are represented to the coeval beds of Liaoning, China; however, the number of species and specimens present at Liaoning is much higher. While the general phylogenetic composition of western European and Chinese communities appear to have been approximately similar, the differences may be due to different palaeoenvironmental and depositional settings. The western Europe pterodactyloid record may therefore be artificially low in diversity due to preservational factors.

Speculative reconstruction of Vectidraco daisymorrisae. We assume that Vectidraco was similar in overall morphology and proportions to Tapejara and other small-bodied azhdarchoids, was edentulous, possibly crested, in possession of relatively short wings, and capable of parasagittal quadrupedal locomotion as shown here.
Total length = c. 350 mm, wingspan = c. 750 mm. |  doi: 10.1371/journal.pone.0058451

Holotype of Vectidraco daisymorrisae; NHMUK PV R36621

Systematic Paleontology

Pterosauria Kaup, 1834.
Pterodactyloidea Plieninger, 1901.
Lophocratia Unwin, 2003.

Azhdarchoidea Nessov, 1984 (sensu Unwin, 1992 [14]).

Vectidraco daisymorrisae, Naish, Simpson, Dyke sp. nov. 

Etymology: Vectis, Greek, Isle of Wight and draco, Greek, dragon, hence ‘dragon from the Isle of Wight’. Specific name honors Daisy Morris, finder of the holotype.

Vectidraco daisymorrisae in flight

A new pterosaur from the Isle of Wight

Palaeontologists from the University of Southampton have made an exciting new discovery from the Isle of Wight – a completely new genus and species of small flying reptile, closely related to dinosaurs, called a ‘pterosaur’.

The pterosaur, which dates from 115 million years ago in the Lower Cretaceous, is currently known only from a well-preserved fossil pelvis, just 40 mm long, but that was enough for the researchers to work out that they were dealing with a new species. The discovery by University of Southampton researchers Dr Darren Naish, ‘fossil man’ Martin Simpson and Dr Gareth Dyke, who are based at the National Oceanography Centre Southampton, is published in the high-profile international journal PLoS One.

The fossil was found in 2008 by Daisy Morris, who was five at the time. In recognition of her find and the generous donation of the fossil by the Morris family to the Natural History Museum, the species has been named Vectidraco daisymorrisae in her honour. The generic name Vectidraco means ‘dragon from the Isle of Wight’ while the species name honours Daisy.

Daisy’s Isle of Wight Dragon

Several features of the Vectidraco fossil allowed the palaeontologists to work out that the species most probably belongs to a group of pterodactyloids called the azhdarchoids. Vectidraco grouped close to the tapejarids (a group of relatively small, short-snouted azhdarchoids known from Brazil, Spain and China), and was probably tapejarid-like in shape and lifestyle. 

Dr Naish says: “Azhdarchoids are, in my opinion, among the most interesting of pterosaurs. All are from the Cretaceous, all are toothless, and many (perhaps all) were especially well adapted for life in terrestrial environments like woodlands, tropical forests and floodplains. Bony head crests are a typical feature of the group, as are adaptations in the fore- and hindlimbs for quadrupedal walking. As well as tapejarids, the group includes the somewhat larger thalassodromids (famous for their sail-like head crests), and the sometimes gigantic, long-snouted azhdarchids.”

By comparing Vectidraco to azhdarchoids known from better remains, it probably had a wingspan of about 75 cm, and was about 35 cm from snout to tail. In other words, it was similar in size to a gull or a large crow. It was probably crested, and with limb proportions that allowed it to be a reasonably good walker and runner on the ground and an expert flier when in cluttered habitats like forests. 

One of the palaeontologists, Martin Simpson, has now written a children's book entitled ‘Daisy and the Isle of Wight Dragon’, about Daisy and her fossil collecting escapades.

Martin says: “The story highlights the special relationship between amateurs, academics and curators, in bringing these important finds to the attention of the scientific world. It also shows that, continuing a long tradition in palaeontology, major discoveries can be made by amateurs, often by being in the right place at the right time.”

The University of Southampton is home to the UK’s largest and most productive vertebrate palaeontology research group working on fossils from the Isle of Wight and collecting new ones.


Naish, D.; Simpson, M.; Dyke, G. 2013. Farke, Andrew A. ed. A New Small-Bodied Azhdarchoid Pterosaur from the Lower Cretaceous of England and Its Implications for Pterosaur Anatomy, Diversity and Phylogeny. PLoS ONE. 8 (3): e58451. doi: 10.1371/journal.pone.0058451

Vectidraco daisymorrisae: Daisy, five, discovers dinosaur and scientists name it after her via @MailOnline

Paleontologists Discover New Pterosaur Genus, Species