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Allen C. Enders - One of the best experts on this subject based on the ideXlab platform.
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placentation in mammals once grouped as insectivores
The International Journal of Developmental Biology, 2010Co-Authors: A M Carter, Allen C. EndersAbstract:Interest in insectivoran grade mammals has been reawakened by taxonomic changes that place Tenrecs and golden moles in a new order and separate hedgehogs from moles, shrews and solenodons. This survey of their placentation shows there is great variation even within families. As an example three subfamilies of Tenrec have been examined. The interhemal region is cellular hemomonochorial in Echinops and Microgale but endotheliochorial in Micropotamogale. Golden moles, which are placed in the same order, have hemodichorial placentation. Many insectivores have complex arrangements for histotrophic nutrition involving columnar trophoblast cells. These range from areolae in moles through complexly folded hemophagous regions in Tenrecs to the trophoblastic annulus in shrews. Of these placental characters, few offer support to current phylogenies. However, the case for placing hedgehogs and gymnures in a separate order (Erinaceomorpha) is bolstered by the presence of interstitial implantation, amniogenesis by cavitation, a hemochorial barrier and a prominent spongy zone; these features do not occur in shrews, moles or solenodons (Soricomorpha). Three insectivoran grade mammals deserve close attention as they have been selected for genome sequencing. One of these, the European hedgehog (Erinaceus europaeus), has not been studied with current methodology and renewed investigation of this or the closely related genus Atelerix should be a priority.
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the fetal membranes of the otter shrews and a synapomorphy for afrotheria
Placenta, 2006Co-Authors: A M Carter, Thomas N Blankenship, Allen C. Enders, P. VogelAbstract:The otter shrews of mainland Africa are the closest relatives of the Madagascar Tenrecs. We sought for similarities in placentation between the two groups and, in a wider context, with other mammals of the Afrotheria clade. Specimens of the Nimba otter shrew ( Micropotamogale lamottei ) were obtained from the Ivory Coast and examples of the giant otter shrew ( Potamogale velox ) from the Hill Collection. The Nimba otter shrew has a central haemophagous organ similar to that in Tenrecs. The labyrinth of the Nimba otter shrew, however, is endotheliochorial with syncytial trophoblast enclosing the maternal vessels. On the other hand Tenrecs have cellular haemomonochorial placentae and an associated spongy zone, which is not present in the Nimba otter shrew. The placenta of the giant otter shrew is also endotheliochorial. The central region of its placenta is particularly interesting, since the juxtafetal portion is clearly a haemophagous region whereas the labyrinth feeding this region is endotheliochorial. Thus there is considerable variation in placental morphology within Tenrecidae. Importantly, however, both otter shrews have a large allantoic sac divided into four intercommunicating lobes by two pairs of septal folds. A similar arrangement has been described for representatives of each of the remaining five orders within Afrotheria. This is significant because previous anatomical studies have failed to establish a single synapomorphy in support of Afrotheria.
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development of the haemophagous region and labyrinth of the placenta of the Tenrec echinops telfairi
Placenta, 2005Co-Authors: A M Carter, Thomas N Blankenship, H Künzle, Allen C. EndersAbstract:Our purpose was to determine how the central haemophagous region and cellular haemomonochorial labyrinth of the Tenrec placenta are formed. The haemophagous region is preceded by a region of invasion of the endometrium by trophoblast comprising a cytotrophoblast layer covered by syncytial trophoblast and contiguous with numerous masses of multinucleate trophoblast. The trophoblast intrudes into the endometrium, eliminating the stroma, although small vessels and clumps of glandular epithelium persist. This extensive central region is connected to the forming disk by a ring of chorioallantois covered by a single layer of columnar trophoblast. Later the multinucleate masses and syncytial trophoblast degenerate. The unilaminar cytotrophoblast remains, is elaborated into folds, and phagocytoses glandular secretion, cell debris and erythrocytes. As the central area is transforming, fetal capillaries move into the cytotrophoblast pads surrounding the central zone. Prior to this, the cytotrophoblast has formed a multilayered structure and interrupted maternal vessels to create an anastomotic network of blood spaces lined by cytotrophoblast. The invasion of fetal capillaries transforms this preplacental pad into a cellular haemomonochorial labyrinth with the uninvaded portion forming an underlying spongy zone. Thus interaction of the trophoblast with the endometrium is substantially different in the central zone compared to the area of the preplacental pad.
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Structure of the definitive placenta of the Tenrec, Echinops telfairi.
Placenta, 2003Co-Authors: A M Carter, Thomas N Blankenship, H Künzle, Allen C. EndersAbstract:Until recently, Tenrecs were classified with insectivores in the order Lipotyphla, but nucleotide sequence data suggest they have closer affinities with a group of African mammals called Afrotheria. The placenta of Echinops has not been described and no studies involving electron microscopy of the placenta of any species of Tenrec have been published. We used light and transmission electron microscopy to examine fixed placentae of embryos ranging from 25-66 mm in length. The placental disk is situated in the antimesometrial portion of the bicornuate uterus. The greater part of the disk consists of a labyrinth underlain by a spongy zone. The interhaemal barrier is unusual in that the trophoblastic component is a single layer of cytotrophoblast. These trophoblast cells have thick areas especially near the nuclei and extensive thin flanges but only occasionally have membrane-closed pore regions. The luminal surface has isolated patches of microvilli, and pinocytotic vesicles are numerous both apically and basally. In the centre of the placental disk is an elaborately folded haemophagous region. The primary folds have allantoic endoderm at one surface and columnar cytotrophoblast at the other. These trophoblast cells have numerous lipid droplets and vesicles, and often contain large yellow pigment crystalloids. The labyrinthine zone ends abruptly at the margins of the placental disk. However, the endoderm and connective tissue of the allantois and a layer of cytotrophoblast extend beyond the placental disk as a paraplacental region. Some of these distinctive features of Echinops placenta are shared with individual afrotherians, but no significant characteristic of definitive placentation is shared by all the Afrotheria.
A M Carter - One of the best experts on this subject based on the ideXlab platform.
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placentation in mammals once grouped as insectivores
The International Journal of Developmental Biology, 2010Co-Authors: A M Carter, Allen C. EndersAbstract:Interest in insectivoran grade mammals has been reawakened by taxonomic changes that place Tenrecs and golden moles in a new order and separate hedgehogs from moles, shrews and solenodons. This survey of their placentation shows there is great variation even within families. As an example three subfamilies of Tenrec have been examined. The interhemal region is cellular hemomonochorial in Echinops and Microgale but endotheliochorial in Micropotamogale. Golden moles, which are placed in the same order, have hemodichorial placentation. Many insectivores have complex arrangements for histotrophic nutrition involving columnar trophoblast cells. These range from areolae in moles through complexly folded hemophagous regions in Tenrecs to the trophoblastic annulus in shrews. Of these placental characters, few offer support to current phylogenies. However, the case for placing hedgehogs and gymnures in a separate order (Erinaceomorpha) is bolstered by the presence of interstitial implantation, amniogenesis by cavitation, a hemochorial barrier and a prominent spongy zone; these features do not occur in shrews, moles or solenodons (Soricomorpha). Three insectivoran grade mammals deserve close attention as they have been selected for genome sequencing. One of these, the European hedgehog (Erinaceus europaeus), has not been studied with current methodology and renewed investigation of this or the closely related genus Atelerix should be a priority.
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the fetal membranes of the otter shrews and a synapomorphy for afrotheria
Placenta, 2006Co-Authors: A M Carter, Thomas N Blankenship, Allen C. Enders, P. VogelAbstract:The otter shrews of mainland Africa are the closest relatives of the Madagascar Tenrecs. We sought for similarities in placentation between the two groups and, in a wider context, with other mammals of the Afrotheria clade. Specimens of the Nimba otter shrew ( Micropotamogale lamottei ) were obtained from the Ivory Coast and examples of the giant otter shrew ( Potamogale velox ) from the Hill Collection. The Nimba otter shrew has a central haemophagous organ similar to that in Tenrecs. The labyrinth of the Nimba otter shrew, however, is endotheliochorial with syncytial trophoblast enclosing the maternal vessels. On the other hand Tenrecs have cellular haemomonochorial placentae and an associated spongy zone, which is not present in the Nimba otter shrew. The placenta of the giant otter shrew is also endotheliochorial. The central region of its placenta is particularly interesting, since the juxtafetal portion is clearly a haemophagous region whereas the labyrinth feeding this region is endotheliochorial. Thus there is considerable variation in placental morphology within Tenrecidae. Importantly, however, both otter shrews have a large allantoic sac divided into four intercommunicating lobes by two pairs of septal folds. A similar arrangement has been described for representatives of each of the remaining five orders within Afrotheria. This is significant because previous anatomical studies have failed to establish a single synapomorphy in support of Afrotheria.
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development of the haemophagous region and labyrinth of the placenta of the Tenrec echinops telfairi
Placenta, 2005Co-Authors: A M Carter, Thomas N Blankenship, H Künzle, Allen C. EndersAbstract:Our purpose was to determine how the central haemophagous region and cellular haemomonochorial labyrinth of the Tenrec placenta are formed. The haemophagous region is preceded by a region of invasion of the endometrium by trophoblast comprising a cytotrophoblast layer covered by syncytial trophoblast and contiguous with numerous masses of multinucleate trophoblast. The trophoblast intrudes into the endometrium, eliminating the stroma, although small vessels and clumps of glandular epithelium persist. This extensive central region is connected to the forming disk by a ring of chorioallantois covered by a single layer of columnar trophoblast. Later the multinucleate masses and syncytial trophoblast degenerate. The unilaminar cytotrophoblast remains, is elaborated into folds, and phagocytoses glandular secretion, cell debris and erythrocytes. As the central area is transforming, fetal capillaries move into the cytotrophoblast pads surrounding the central zone. Prior to this, the cytotrophoblast has formed a multilayered structure and interrupted maternal vessels to create an anastomotic network of blood spaces lined by cytotrophoblast. The invasion of fetal capillaries transforms this preplacental pad into a cellular haemomonochorial labyrinth with the uninvaded portion forming an underlying spongy zone. Thus interaction of the trophoblast with the endometrium is substantially different in the central zone compared to the area of the preplacental pad.
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Placentation in species of phylogenetic importance: the Afrotheria.
Animal reproduction science, 2004Co-Authors: A M Carter, A C Enders, H Künzle, D Oduor-okelo, P. VogelAbstract:Afrotheria, one of four mammalian superorders, comprises elephants, sea cows, hyraxes, aardvark, elephant shrews, Tenrecs and golden moles. Their placentas either form an equatorial band or are discoid in shape. The interhemal region, separating fetal and maternal blood, is endotheliochorial in elephants, aardvark and possibly the sea cows, but hemochorial in the remaining orders. There is a secondary epitheliochorial placenta in elephant shrews while a similar structure in Tenrecs erodes maternal tissues. Specialized hemophagous regions are a striking characteristic of some of these placentas yet absent in hyraxes, elephant shrews, and golden moles. It is possible that the common ancestor of the Afrotheria had an endotheliochorial placenta. Establishment of a hemochorial condition, as seen in rock hyraxes, elephant shrews, Tenrecs, and golden moles, would be a more recent development. The elephant, manatee, and aardvark all have circumferential placentas. Thus the formation of a discoid placenta with a more or less extensive secondary placenta in elephant shrews and Tenrecs would also be a derived state.
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Structure of the definitive placenta of the Tenrec, Echinops telfairi.
Placenta, 2003Co-Authors: A M Carter, Thomas N Blankenship, H Künzle, Allen C. EndersAbstract:Until recently, Tenrecs were classified with insectivores in the order Lipotyphla, but nucleotide sequence data suggest they have closer affinities with a group of African mammals called Afrotheria. The placenta of Echinops has not been described and no studies involving electron microscopy of the placenta of any species of Tenrec have been published. We used light and transmission electron microscopy to examine fixed placentae of embryos ranging from 25-66 mm in length. The placental disk is situated in the antimesometrial portion of the bicornuate uterus. The greater part of the disk consists of a labyrinth underlain by a spongy zone. The interhaemal barrier is unusual in that the trophoblastic component is a single layer of cytotrophoblast. These trophoblast cells have thick areas especially near the nuclei and extensive thin flanges but only occasionally have membrane-closed pore regions. The luminal surface has isolated patches of microvilli, and pinocytotic vesicles are numerous both apically and basally. In the centre of the placental disk is an elaborately folded haemophagous region. The primary folds have allantoic endoderm at one surface and columnar cytotrophoblast at the other. These trophoblast cells have numerous lipid droplets and vesicles, and often contain large yellow pigment crystalloids. The labyrinthine zone ends abruptly at the margins of the placental disk. However, the endoderm and connective tissue of the allantois and a layer of cytotrophoblast extend beyond the placental disk as a paraplacental region. Some of these distinctive features of Echinops placenta are shared with individual afrotherians, but no significant characteristic of definitive placentation is shared by all the Afrotheria.
Heinz Künzle - One of the best experts on this subject based on the ideXlab platform.
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transposition and intermingling of gαi2 and gαo afferences into single vomeronasal glomeruli in the madagascan lesser Tenrec echinops telfairi
PLOS ONE, 2009Co-Authors: Rodrigo Suarez, Heinz Künzle, Aldo Villalon, Jorge MpodozisAbstract:The vomeronasal system (VNS) mediates pheromonal communication in mammals. From the vomeronasal organ, two populations of sensory neurons, expressing either Gαi2 or Gαo proteins, send projections that end in glomeruli distributed either at the rostral or caudal half of the accessory olfactory bulb (AOB), respectively. Neurons at the AOB contact glomeruli of a single subpopulation. The dichotomic segregation of AOB glomeruli has been described in opossums, rodents and rabbits, while Primates and Laurasiatheres present the Gαi2-pathway only, or none at all (such as apes, some bats and aquatic species). We studied the AOB of the Madagascan lesser Tenrec Echinops telfairi (Afrotheria: Afrosoricida) and found that Gαi2 and Gαo proteins are expressed in rostral and caudal glomeruli, respectively. However, the segregation of vomeronasal glomeruli at the AOB is not exclusive, as both pathways contained some glomeruli transposed into the adjoining subdomain. Moreover, some glomeruli seem to contain intermingled afferences from both pathways. Both the transposition and heterogeneity of vomeronasal afferences are features, to our knowledge, never reported before. The organization of AOB glomeruli suggests that synaptic integration might occur at the glomerular layer. Whether intrinsic AOB neurons may make synaptic contact with axon terminals of both subpopulations is an interesting possibility that would expand our understanding about the integration of vomeronasal pathways.
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Transposition and intermingling of Gai2 and Gao afferences into single vomeronasal glomeruli in the Madagascan lesser Tenrec Echinops telfairi. PLoS ONE 4(11): e8005. mouse secondary antibodies (1:200, cat no. sc-2039, Santa Cruz Biotechnology, Santa Cruz
2009Co-Authors: Rodrigo Suarez, Heinz Künzle, Aldo Villalon, Jorge MpodozisAbstract:The vomeronasal system (VNS) mediates pheromonal communication in mammals. From the vomeronasal organ, two populations of sensory neurons, expressing either Gai2 or Gao proteins, send projections that end in glomeruli distributed either at the rostral or caudal half of the accessory olfactory bulb (AOB), respectively. Neurons at the AOB contact glomeruli of a single subpopulation. The dichotomic segregation of AOB glomeruli has been described in opossums, rodents and rabbits, while Primates and Laurasiatheres present the Gai2-pathway only, or none at all (such as apes, some bats and aquatic species). We studied the AOB of the Madagascan lesser Tenrec Echinops telfairi (Afrotheria: Afrosoricida) and found that Gai2 and Gao proteins are expressed in rostral and caudal glomeruli, respectively. However, the segregation of vomeronasal glomeruli at the AOB is not exclusive, as both pathways contained some glomeruli transposed into the adjoining subdomain. Moreover, some glomeruli seem to contain intermingled afferences from both pathways. Both the transposition and heterogeneity of vomeronasal afferences are features, to our knowledge, never reported before. The organization of AOB glomeruli suggests that synaptic integration might occur at the glomerular layer. Whether intrinsic AOB neurons may make synaptic contact with axon terminals of both subpopulations is an interesting possibility that woul
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histological study of the cloacal region and associated structures in the hedgehog Tenrec echinops telfairi
Mammalian Biology, 2007Co-Authors: Bernd Riedelsheimer, Heinz Künzle, Pia Unterberger, Ulrich WelschAbstract:Abstract The present investigation is based on several careful dissections and on extensive series of histological sections. It has led us to the conclusion that adult male and female Echinops telfairi are in the possession of a cloaca which represents a primitive feature among mammals. This cloaca is a small, bowl-shaped pouch at the ventro-posterior end of the body. Intestinal, genital and urinary tract open into this cloaca. The opening of the intestinal tract into the cloaca is regulated by a sphincter muscle. In the female the genital and the urinary tract open into the urogenital sinus, a subcompartment of the cloaca. The cloaca of the lesser hedgehog Tenrec is lined by a multilayered, non-keratinized squamous epithelium without skin glands. In a small transitory zone between the cloaca and the outer skin the epithelium changes into the keratinized, multilayered squamous epithelium of the epidermis with eccrine and holocrine glands as well as hairs. In addition, there is a distinct circular cloacal sphincter muscle, built up by cross-striated skeletal muscle tissue. In the terminal parts of intestinal, urinary and genital tracts of male animals the following glandular structures were observed: prostate gland, Cowper's glands and strongly pigmented seminal vesicles; in female animals: the urethral and the Bartholin glands. Both males and females, in addition, possess (a) a cloacal gland, the excretory ducts of which open into the cloaca and (b) a pericloacal gland which is located in the adipose tissue on both sides of the cloaca; it presumably also opens into the cloaca.
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an extrahippocampal projection from the dentate gyrus to the olfactory tubercle
BMC Neuroscience, 2005Co-Authors: Heinz KünzleAbstract:The dentate gyrus is well known for its mossy fiber projection to the hippocampal field 3 (CA3) and its extensive associational and commissural connections. The dentate gyrus, on the other hand, has only few projections to the CA1 and the subiculum, and none have clearly been shown to extrahippocampal target regions. Using anterograde and retrograde tracer techniques in the Madagascan lesser hedgehog Tenrec (Afrosoricidae, Afrotheria) it was shown in this study that the dentate hilar region gave rise to a faint, but distinct, bilateral projection to the most rostromedial portion of the olfactory tubercle, particularly its molecular layer. Unlike the CA1 and the subiculum the dentate gyrus did not project to the accumbens nucleus. A control injection into the medial septum-diagonal band complex also retrogradely labeled cells in the dentate hilus, but these neurons were found immediately adjacent to the heavily labeled CA3, while the tracer injections into the rostromedial tubercle did not reveal any labeling in CA3. The dentate hilar neurons projecting to the olfactory tubercle cannot be considered displaced cells of CA3 but represent true dentato-tubercular projection neurons. This projection supplements the subiculo-tubercular projection. Both terminal fields overlap among one another as well as with the fiber terminations arising in the anteromedial frontal cortex. The rostromedial olfactory tubercle might represent a distinct ventral striatal target area worth investigating in studies of the parallel processing of cortico-limbic information in Tenrec as well as in cat and monkey.
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An extrahippocampal projection from the dentate gyrus to the olfactory tubercle
BMC Neuroscience, 2005Co-Authors: Heinz KünzleAbstract:Background The dentate gyrus is well known for its mossy fiber projection to the hippocampal field 3 (CA3) and its extensive associational and commissural connections. The dentate gyrus, on the other hand, has only few projections to the CA1 and the subiculum, and none have clearly been shown to extrahippocampal target regions. Results Using anterograde and retrograde tracer techniques in the Madagascan lesser hedgehog Tenrec (Afrosoricidae, Afrotheria) it was shown in this study that the dentate hilar region gave rise to a faint, but distinct, bilateral projection to the most rostromedial portion of the olfactory tubercle, particularly its molecular layer. Unlike the CA1 and the subiculum the dentate gyrus did not project to the accumbens nucleus. A control injection into the medial septum-diagonal band complex also retrogradely labeled cells in the dentate hilus, but these neurons were found immediately adjacent to the heavily labeled CA3, while the tracer injections into the rostromedial tubercle did not reveal any labeling in CA3. Conclusion The dentate hilar neurons projecting to the olfactory tubercle cannot be considered displaced cells of CA3 but represent true dentato-tubercular projection neurons. This projection supplements the subiculo-tubercular projection. Both terminal fields overlap among one another as well as with the fiber terminations arising in the anteromedial frontal cortex. The rostromedial olfactory tubercle might represent a distinct ventral striatal target area worth investigating in studies of the parallel processing of cortico-limbic information in Tenrec as well as in cat and monkey.
Steven M. Goodman - One of the best experts on this subject based on the ideXlab platform.
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Description of three new species of Ixodes Latreille, 1795 (Acari: Ixodidae), parasites of Tenrecs (Afrotheria: Tenrecidae) on Madagascar
Systematic Parasitology, 2020Co-Authors: Dmitry A. Apanaskevich, Steven M. GoodmanAbstract:Ixodes soarimalalae n. sp., Ixodes uilenbergi n. sp. and Ixodes uncus n. sp. (Acari: Ixodidae), are described based on females ex various species of Tenrecs (Afrosoricida: Tenrecidae) from Madagascar. Females of all of these new species are similar to those of other species of the subgenus Afrixodes Morel, 1966 known from Madagascar, from which they can be distinguished and from one other by the size of scutum, size of scutal setae, shape of alloscutal setae, shape of genital aperture, development of genital apron, size of auriculae, size of anterior angle of basis capituli, size of palpi, dental formula on hypostome and size and development of spurs on coxa I.
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2007, Description of a new species of subfossil shrew-Tenrec (Afrosoricida: Tenrecidae: Microgale) from cave deposits
2020Co-Authors: Steven M. Goodman, Natalie Vasey, David A BurneyAbstract:Abstract.-A new species of shrew Tenrec, Microgale macpheei, is described from subfossil deposits in Andrahomana Cave, extreme southeastern Madagascar. This species is distinguished from all named taxa of Microgale by a variety of osteological, dental, and mensural characters. It is presumed to be the sister taxon to the extant species M. brevicaudata, which is not known to occur in southeastern Madagascar. Although the genus contains well over 20 living species, M. macpheei is the first known extinct shrew Tenrec in the Quaternary fauna of Madagascar. Résumé.-Une nouvelle espèce de microgale, Microgale macpheei, trouvée dans les dépô ts subfossiles de la grotte d'Andrahomana, dans l'extrême sud de Madagascar, est décrite. Cette espèce se distingue de tous les taxons nommés dans ce genre par divers caractères portant sur l'ostéologie, la dentition et les mesures. Elle semble montrer des affinités avec l'espèce actuelle M. brevicaudata qui n'est pas connue du sud-est de Madagascar. Bien que le genre soit représenté par bien plus de 20 espèces vivantes, la description de M. macpheei constitue la première évidence d'un microgale éteint dans la faune du Quaternaire de Madagascar
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Review of the status and conservation of Tenrecs (Mammalia: Afrotheria: Tenrecidae)
Oryx, 2019Co-Authors: P. J. Stephenson, Steven M. Goodman, Link E Olson, Voahangy Soarimalala, Martin E. Nicoll, Vonjy Andrianjakarivelo, Kathryn M. Everson, Michael Hoffmann, Paulina D. Jenkins, Martin RaheriarisenaAbstract:AbstractThe mammal family Tenrecidae (Afrotheria: Afrosoricida) is endemic to Madagascar. Here we present the conservation priorities for the 31 species of Tenrec that were assessed or reassessed in 2015–2016 for the IUCN Red List of Threatened Species. Six species (19.4%) were found to be threatened (4 Vulnerable, 2 Endangered) and one species was categorized as Data Deficient. The primary threat to Tenrecs is habitat loss, mostly as a result of slash-and-burn agriculture, but some species are also threatened by hunting and incidental capture in fishing traps. In the longer term, climate change is expected to alter Tenrec habitats and ranges. However, the lack of data for most Tenrecs on population size, ecology and distribution, together with frequent changes in taxonomy (with many cryptic species being discovered based on genetic analyses) and the poorly understood impact of bushmeat hunting on spiny species (Tenrecinae), hinders conservation planning. Priority conservation actions are presented for Madagascar's Tenrecs for the first time since 1990 and focus on conserving forest habitat (especially through improved management of protected areas) and filling essential knowledge gaps. Tenrec research, monitoring and conservation should be integrated into broader sustainable development objectives and programmes targeting higher profile species, such as lemurs, if we are to see an improvement in the conservation status of Tenrecs in the near future.
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Identification of Tenrec ecaudatus, a Wild Mammal Introduced to Mayotte Island, as a Reservoir of the Newly Identified Human Pathogenic Leptospira mayottensis
PLoS Neglected Tropical Diseases, 2016Co-Authors: Erwan Lagadec, Steven M. Goodman, Eric Cardinale, Colette Cordonin, Yann Gomard, Pablo Tortosa, Gildas Le Minter, Beza Ramasindrazana, Muriel Dietrich, Koussay DellagiAbstract:Leptospirosis is a bacterial zoonosis of major concern on tropical islands. Human populations on western Indian Ocean islands are strongly affected by the disease although each archipelago shows contrasting epidemiology. For instance, Mayotte, part of the Comoros Archipelago, differs from the other neighbouring islands by a high diversity of Leptospira species infecting humans that includes Leptospira mayottensis, a species thought to be unique to this island. Using bacterial culture, molecular detection and typing, the present study explored the wild and domestic local mammalian fauna for renal carriage of leptospires and addressed the genetic relationships of the infecting strains with local isolates obtained from acute human cases and with Leptospira strains hosted by mammal species endemic to nearby Madagascar. Tenrec (Tenrec ecaudatus, Family Tenrecidae), a terrestrial mammal introduced from Madagascar, is identified as a reservoir of L. mayottensis. All isolated L. mayottensis sequence types form a monophyletic clade that includes Leptospira strains infecting humans and Tenrecs on Mayotte, as well as two other Malagasy endemic Tenrecid species of the genus Microgale. The lower diversity of L. mayottensis in Tenrecs from Mayotte, compared to that occurring in Madagascar, suggests that L. mayottensis has indeed a Malagasy origin. This study also showed that introduced rats (Rattus rattus) and dogs are probably the main reservoirs of Leptospira borgpetersenii and Leptospira kirschneri, both bacteria being prevalent in local clinical cases. Data emphasize the epidemiological link between the two neighbouring islands and the role of introduced small mammals in shaping the local epidemiology of leptospirosis.
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Bayesian phylogenetic tree of pathogenic Leptospira species from Mayotte (blue) and Madagascar (green) based on concatenated sequences of five genes (secY, adk, lipL32, lipL41 and rrs2, total size: 2215 bp).
2016Co-Authors: Erwan Lagadec, Steven M. Goodman, Eric Cardinale, Colette Cordonin, Yann Gomard, Pablo Tortosa, Beza Ramasindrazana, Muriel Dietrich, Gildas Le Minter, Koussay DellagiAbstract:The analysis was realized under the GTR+G substitution model. At the nodes, grey and white circles indicate posterior probabilities superior to 0.70 and 0.90, respectively. Strain numbers of cultures produced herein are indicated in parentheses, “K” and “U” designating the sequences obtained from kidney or urine, respectively. Stars indicate lineages common to humans and animals (Rattus rattus or Tenrec ecaudatus). For Homo sapiens str. 200901122, the same sequence type was found in nine cultures from T. ecaudatus (2014TE MDI222, 2014TE MDI224, 2014TE MDI294U, 2014TE MDI295, 2014TE MDI295U, 2014TE MDI306, 2014TE MD308, 2014TE MDI321 and 2014TE MDI321U). For H. sapiens str. 200701204, 200900806, 200901483 and 201003760, the same sequence type found was in seven cultures from R. rattus (2014RR MDI247, 2014RR MDI250, 2014RR MDI251, 2014RR MDI259, 2014RR MDI260, 2014RR MDI284 and 2014RR MDI291). Specimen system: MDI = CRVOI specimen catalogue during field trips to Mayotte; FMNH = Field Museum of Natural History, Chicago; UADBA = Université d’Antananarivo, Département de Biologie Animale, Madagascar; for the other bacterial sequences from H. sapiens and Microgale spp. see Bourhy et al. 2012 [15] and Dietrich et al. 2014 [4]. Museum numbers for Microgale spp.: 575 = UADBA 30869; 588 = UADBA 30289; 590 = UADBA 30291; 1335 = UADBA 32122; 1453 = UADBA 32125; 1467 = UADBA 32101.
Koussay Dellagi - One of the best experts on this subject based on the ideXlab platform.
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Identification of Tenrec ecaudatus, a Wild Mammal Introduced to Mayotte Island, as a Reservoir of the Newly Identified Human Pathogenic Leptospira mayottensis
PLoS Neglected Tropical Diseases, 2016Co-Authors: Erwan Lagadec, Steven M. Goodman, Eric Cardinale, Colette Cordonin, Yann Gomard, Pablo Tortosa, Gildas Le Minter, Beza Ramasindrazana, Muriel Dietrich, Koussay DellagiAbstract:Leptospirosis is a bacterial zoonosis of major concern on tropical islands. Human populations on western Indian Ocean islands are strongly affected by the disease although each archipelago shows contrasting epidemiology. For instance, Mayotte, part of the Comoros Archipelago, differs from the other neighbouring islands by a high diversity of Leptospira species infecting humans that includes Leptospira mayottensis, a species thought to be unique to this island. Using bacterial culture, molecular detection and typing, the present study explored the wild and domestic local mammalian fauna for renal carriage of leptospires and addressed the genetic relationships of the infecting strains with local isolates obtained from acute human cases and with Leptospira strains hosted by mammal species endemic to nearby Madagascar. Tenrec (Tenrec ecaudatus, Family Tenrecidae), a terrestrial mammal introduced from Madagascar, is identified as a reservoir of L. mayottensis. All isolated L. mayottensis sequence types form a monophyletic clade that includes Leptospira strains infecting humans and Tenrecs on Mayotte, as well as two other Malagasy endemic Tenrecid species of the genus Microgale. The lower diversity of L. mayottensis in Tenrecs from Mayotte, compared to that occurring in Madagascar, suggests that L. mayottensis has indeed a Malagasy origin. This study also showed that introduced rats (Rattus rattus) and dogs are probably the main reservoirs of Leptospira borgpetersenii and Leptospira kirschneri, both bacteria being prevalent in local clinical cases. Data emphasize the epidemiological link between the two neighbouring islands and the role of introduced small mammals in shaping the local epidemiology of leptospirosis.
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Bayesian phylogenetic tree of pathogenic Leptospira species from Mayotte (blue) and Madagascar (green) based on concatenated sequences of five genes (secY, adk, lipL32, lipL41 and rrs2, total size: 2215 bp).
2016Co-Authors: Erwan Lagadec, Steven M. Goodman, Eric Cardinale, Colette Cordonin, Yann Gomard, Pablo Tortosa, Beza Ramasindrazana, Muriel Dietrich, Gildas Le Minter, Koussay DellagiAbstract:The analysis was realized under the GTR+G substitution model. At the nodes, grey and white circles indicate posterior probabilities superior to 0.70 and 0.90, respectively. Strain numbers of cultures produced herein are indicated in parentheses, “K” and “U” designating the sequences obtained from kidney or urine, respectively. Stars indicate lineages common to humans and animals (Rattus rattus or Tenrec ecaudatus). For Homo sapiens str. 200901122, the same sequence type was found in nine cultures from T. ecaudatus (2014TE MDI222, 2014TE MDI224, 2014TE MDI294U, 2014TE MDI295, 2014TE MDI295U, 2014TE MDI306, 2014TE MD308, 2014TE MDI321 and 2014TE MDI321U). For H. sapiens str. 200701204, 200900806, 200901483 and 201003760, the same sequence type found was in seven cultures from R. rattus (2014RR MDI247, 2014RR MDI250, 2014RR MDI251, 2014RR MDI259, 2014RR MDI260, 2014RR MDI284 and 2014RR MDI291). Specimen system: MDI = CRVOI specimen catalogue during field trips to Mayotte; FMNH = Field Museum of Natural History, Chicago; UADBA = Université d’Antananarivo, Département de Biologie Animale, Madagascar; for the other bacterial sequences from H. sapiens and Microgale spp. see Bourhy et al. 2012 [15] and Dietrich et al. 2014 [4]. Museum numbers for Microgale spp.: 575 = UADBA 30869; 588 = UADBA 30289; 590 = UADBA 30291; 1335 = UADBA 32122; 1453 = UADBA 32125; 1467 = UADBA 32101.