Blanco M.B.,Duke Lemur Center |
Godfrey L.R.,University of Massachusetts Amherst
International Journal of Primatology | Year: 2013
The classic mammalian life history continuum polarizes small-bodied species that live fast and die young from larger-bodied species with longer life spans and reduced adult mortality rates. Hibernating mammals, however, deviate from this pattern and tend to have short gestations, accelerated early infant growth in preparation for hibernation, retardation of growth and development in association with hibernation, and delayed achievement of full adult size and first reproduction. This pattern has never been systematically tested in hibernating primates. We examine body mass, growth trajectories, dental development, and reproductive status of dwarf lemurs (genus Cheirogaleus), the only obligate hibernators among primates, to determine whether life histories in these small-bodied strepsirrhines vary in accord with expectations based on the use of energy-saving strategies. We show that this pattern does indeed hold for primates. Unlike similarly sized nonhibernating strepsirrhines such as bush babies (genus Galago), wild dwarf lemurs display short gestation and lactation periods, rapid early (pre-hibernation) growth and development followed by retardation of growth and dental development during hibernation, delayed attainment of adult size, and delayed first reproduction. We conclude that hibernation constrains the degree to which dwarf lemurs can experience life in the fast lane. Cheirogaleus have life history profiles that are neither fast nor slow but a combination of both. © 2012 Springer Science+Business Media New York.
Boyer D.M.,Brooklyn College |
Seiffert E.R.,State University of New York at Stony Brook |
Simons E.L.,Duke Lemur Center
American Journal of Physical Anthropology | Year: 2010
The ∼37 million-year-old Birket Qarun Locality 2 (BQ-2), in the Birket Qarun Formation of Egypt's Fayum Depression, yields evidence for a diverse primate fauna, including the earliest known lorisiforms, parapithecoid anthropoids, and Afradapis longicristatus, a large folivorous adapiform. Phylogenetic analysis has placed Afradapis as a stem strepsirrhine within a clade of caenopithecine adapiforms, contradicting the recently popularized alternative hypothesis aligning adapiforms with haplorhines or anthropoids. We describe an astragalus from BQ-2 (DPC 21445C), attributable to Afradapis on the basis of size and relative abundance. The astragalus is remarkably similar to those of extant lorises, having a low body, no posterior shelf, a broad head and neck. It is like extant strepsirrhines more generally, in having a fibular facet that slopes gently away from the lateral tibial facet, and in having a groove for the tendon of flexor fibularis that is lateral to the tibial facet. Comparisons to a sample of euarchontan astragali show the new fossil to be most similar to those of adapines and lorisids. The astragali of other adapiforms are most similar to those of lemurs, but distinctly different from those of all anthropoids. Our measurements show that in extant strepsirrhines and adapiforms the fibular facet slopes away from the lateral tibial facet at a gradual angle (112-126°), in contrast to the anthropoid fibular facet, which forms a sharper angle (87-101°). Phylogenetic analyses incorporating new information from the astragalus continue to support strepsirrhine affinities for adapiforms under varying models of character evolution. Copyright © 2010 Wiley-Liss, Inc.
Barrowa E.,University of Oxford |
Seiffertb E.R.,Health Science University |
Simonsc E.L.,Duke Lemur Center
Journal of Systematic Palaeontology | Year: 2010
A new hyracoid genus and species, Dimaitherium patnaiki from the early Late Eocene (early Priabonian) Birket Qarun Formation in the Fayum Depression, Egypt, is described. The material is approximately 37 million years old and three million years older than any other hyracoid known from the Fayum area. A partial cranium preserves features that are likely primitive within Paenungulata, such as a postorbital process made up solely of the frontals (without a parietal contribution), a restricted jugal contribution to the anterior orbitalmargin, and an anteriorly positioned orbit. The internalmandibular fenestra, a peculiar feature seen in many younger Fayum hyracoids, is primitively absent in Dimaitherium, but a coronoid canal is present at the base of the ascending ramus as in later hyracoids. The dentition of Dimaitherium shows several primitive characteristics, such as poorly molarised premolars, but otherwise differs little from many younger hyracoids. Phylogenetic analysis consistently places younger hyracoids, including procaviids, in a clade to the exclusion of Dimaitherium and the much older Seggeurius and Microhyrax. Given the phylogenetic hypotheses proposed here, the presence of 'broken' hypocristids on the lower molars is likely to have evolved more than once during hyracoid evolution. Evidence from the humerus, astragalus and calcaneum indicate that Dimaitherium may have been an agile climber, and was likely capable of rapid movement but was not cursorially adapted. Of the other two small Fayum hyracoids, Dimaitherium was more similar to Thyrohyrax than to Saghatherium. The presence of only this single genus and species in the Birket Qarun localities cannot be explained by depositional biases, and makes an ancient origin for the Fayum hyracoid lineages unlikely. The poorly known large-bodied Early Eocene hyracoids 'Megalohyrax' gevini and 'Titanohyrax' mongereaui and tantulus from Algeria and Tunisia were not placed with Fayum species of Megalohyrax or Titanohyrax in our phylogenetic analyses. It is unlikely that these species belong to those genera and provide no compelling evidence for an Early Eocene or Paleocene divergence of the Fayum hyracoid lineages. © 2010 The Natural History Museum.
In a study led by Duke University, researchers used a technique called whole-transcriptome sequencing to screen for blood-borne diseases in wild lemurs, distant primate cousins to humans. The animals were found to carry several strains or species of parasites similar to those that cause Lyme disease and other infections in humans. This is the first time these parasites have been reported in lemurs or in Madagascar, the only place on Earth where lemurs live in the wild outside of zoos and sanctuaries, the researchers report in the Jan. 27, 2016 issue of Biology Letters. The approach could pave the way for earlier, more accurate detection of future outbreaks of zoonotic diseases that move between animals and people. "We can detect pathogens we might not expect and be better prepared to deal with them," said co-author Anne Yoder, director of the Duke Lemur Center. In 2012, Duke Lemur Center veterinarian Cathy Williams and colleagues started performing physical exams on lemurs in the rainforests surrounding a mine site in eastern Madagascar to help monitor the impacts of such activities on lemur health. "Lemur populations are becoming increasingly small and fragmented because of human activities like mining, logging and clearing forests to make way for cattle grazing and rice paddies," Williams said. "If an infectious disease wipes out a lemur population it could be a huge blow to the species." Researchers took small amounts of blood and tested them for evidence of exposure to known viruses and pathogens, but nothing turned up. The problem is that standard diagnostic tests tend to target known pathogens, Williams said. You can check for antibodies to certain viruses, or look for specific snippets of genetic material in an animal's blood, "but you have to know what you're looking for." The end result is that new or exotic diseases often go undetected. And with hundreds of thousands of viral and bacterial species that lemurs and other mammals harbor still awaiting discovery, "we could be looking for anything," Williams said. To cast a wider net they tried a new approach. Lead author Peter Larsen, senior research scientist at Duke, analyzed blood samples from six lemurs in two species, the indri and the diademed sifaka, both of which are considered critically endangered by the International Union for Conservation of Nature (IUCN). With advances in high-throughput sequencing, the ability to read genetic code rapidly, Larsen was able to look at all the gene readouts, or RNA transcripts, that were present in each animal—an alphabet soup containing billions of nucleotide bases. The team found more than just lemur RNA in the animals' blood. Using computer algorithms that compared the genetic material to sequences already catalogued in existing databases, they discovered several new types of parasites that had never been reported in lemurs. These included a new form of the protozoa responsible for babesiosis, a disease spread by bites from infected ticks, and a new kind of Borrelia closely related to the bacterium that causes Lyme disease. They also found the first known case in Madagascar of a bacterium called Candidatus Neoehrlichia, which can be deadly in humans. Further analyses revealed that the new types of Babesia and Borrelia they found didn't begin in lemurs, but were likely introduced to Madagascar in infected pets and livestock such as cattle and then spilled over to lemurs. The researchers don't yet know if the new parasites are actually dangerous to lemurs. But they caution that what is infecting lemurs could potentially infect people, too. Human health officials and veterinarians in Madagascar may want to consider screening their patients to see if any test positive for the same parasites, the researchers say. The majority of emerging infectious diseases that affect humans, including recent outbreaks of SARS, Ebola and bird flu, are zoonotic—they can spread among wildlife, domestic animals and humans. "Next-generation sequencing will be an important tool to identify emerging pathogens, particularly vector-borne diseases," said Barbara Qurollo, a research assistant professor at the N.C. State College of Veterinary Medicine who was not affiliated with the study. "A clinician cannot treat an infection that he or she does not know exists," said veterinarian and infectious diseases researcher Edward Breitschwerdt, also of the N.C. State College of Veterinary Medicine. "The kindest form of therapy is an accurate diagnosis." More information: Blood transcriptomes reveal novel parasitic zoonoses circulating in Madagascar's lemurs, Biology Letters, rsbl.royalsocietypublishing.org/lookup/doi/10.1098/rsbl.2015.0829
The results appear online April 20 in Royal Society Open Science. The "perfume" of the ring-tailed lemur could never be confused with Chanel. Male ring-tailed lemurs, our distant primate cousins, produce their distinctive musky odor with help from a pair of glands on their wrists that give off droplets of clear, fast-evaporating fluid, and a second pair of glands on their chests that secrete a brown, foul-smelling paste. Males use their scents to mark territories and tell rivals to back off. Sometimes they deposit wrist secretions alone, rubbing their wrists directly onto branches and saplings. Other times they mix the two, pressing the insides of their wrists against their chest glands to mingle the scents. They also smear the pungent mixture on their tails, waving them in the air and wafting them at opponents to see who can outstink the other in a ritual called "stink-fighting." Many animals combine odors from sources such as glands, urine, feces and saliva, but why they sometimes blend and layer these fragrances, and other times deposit them alone, is not well understood. To find out why lemurs mix their scents, researchers presented pure and mixed scent secretions from unfamiliar males to 12 ring-tailed lemurs at the Duke Lemur Center in Durham, North Carolina. The secretions were collected with cotton swabs and then rubbed onto three wooden rods—one rod with wrist secretions only, another with secretions from the chest, and a third with a mixture. Each male participated in two sets of trials, one set with fresh secretions and another in which the secretions were allowed to air out and evaporate for 12 hours first. The researchers found that the lemurs paid more attention to the mixtures, spending more time sniffing rods covered with mixed secretions than pure ones. Surprisingly, the lemurs showed an even stronger preference for mixed secretions after the scents had aired out, shifting from sniffing them when fresh to licking them intently when dried. The results suggest that mixing scents serves two purposes. First, like blending perfumes with complementary notes, blending secretions may increase the amount of information conveyed by a single dab of scent, said Christine Drea, a professor of evolutionary anthropology at Duke who led the study. The wrist and chest secretions of male ring-tailed lemurs differ somewhat in composition, previous studies show. Chemical analyses have identified dozens of odor molecules in the wrist secretions alone. Mixing wrist and chest secretions may also lock in the more fleeting aromas and boost their staying power, said co-first author Lydia Greene, a graduate student at Duke. The greasy goo from the chest glands contains a chemical called squalene, an oily substance produced by many plants and animals and commonly used as a preservative in perfumes and skincare products. The longer-lasting mixtures that result may send a signal to males from other groups, who may not wander by a scent-marked tree or sapling until days later, the researchers say. Explore further: Primate's scent speaks volumes about who he is More information: Mix it and fix it: functions of composite olfactory signals in ring-tailed lemurs, Royal Society Open Science, rsos.royalsocietypublishing.org/lookup/doi/10.1098/rsos.160076