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Daryl P. Domning - One of the best experts on this subject based on the ideXlab platform.
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Libysiren sickenbergi, gen. et sp. nov.: A New Sirenian (Mammalia, Protosirenidae) from the Middle Eocene of Libya
Journal of Vertebrate Paleontology, 2017Co-Authors: Daryl P. Domning, Geoffrey J. Heal, Silvia SorbiAbstract:ABSTRACTFossil Sirenian specimens collected in 1964 by the late R. J. G. Savage's expeditions in north-central Libya are described. They come from early middle Eocene (lower Lutetian, 47.8–43.6 Ma) deposits at the locality of Bu el Haderait and represent a new genus and species, Libysiren sickenbergi. This animal is the largest known protosirenid, and the largest Eocene Sirenian known to date (condylobasal length >420 mm). Its dental formula was apparently 3.1.5.3, with five premolar loci as in all other Eocene Sirenians, but the teeth are mostly not preserved. Its postcranial skeleton is unknown except for the atlas, a thoracic vertebra, and rib fragments. Stable isotopes indicate a mostly seagrass diet and a habitat of fully marine salinity. The Protosirenidae presently comprise the genera Protosiren, Ashokia, and Libysiren, with their interrelationships unresolved. Together, they are most parsimoniously regarded as a paraphyletic group basal to both Trichechidae and Dugongidae. However, as more of thei...
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Marsh, H., T. J. O'Shea, and J. E. Reynolds III. 2011. Ecology and Conservation of the Sirenia: Dugongs and Manatees. Cambridge University Press, Cambridge, United Kingdom, 536 pp. Series: Conservation Biology No. 18. ISBN-978-0-521-88828-8
Journal of Mammalogy, 2012Co-Authors: Daryl P. DomningAbstract:H. T. J. O'Shea Marsh, J. E. Reynolds III 2011.Ecology and Conservation of the Sirenia: Dugongs and Manatees. Cambridge University Press, Cambridge, United Kingdom, 536 pp. Series: Conservation Biology No. 18. ISBN-978-0-521-88828-8 and ISBN-978-0-521-71643-7, price (hardbound), $135.00, (paper) $65.00. When I 1st began seriously studying mammals, there were almost no books (as distinct from technical monographs in serials) devoted to Sirenians, except for Colin Bertram's (1963) In Search of Mermaids. Then came Hartman's (1979) landmark American Society of Mammalogists publication, around the same time as several workshop proceedings on manatees and dugongs and a surge of other primary literature. That surge has continued uninterrupted to the present day, and now there are several substantial books in English, with various scopes, emphases, and levels of technical detail, including Reynolds and Odell (1991), Zeiller (1992), Powell (2002), and Reep and Bonde (2006), in addition to extensive Sirenian information in Reynolds and Rommel (1999), Twiss and Reeves (1999), and other more general works. Several of these are useful as reference works for professional mammalogists, or as texts for undergraduate or graduate courses, or both. But all of them are eclipsed in these roles by the present volume. Helene Marsh, Tom O'shea, and John Reynolds all stand in the 1st rank among the scores of workers who have contributed to our knowledge of the living Sirenians during the past 35 years: Marsh as the longtime leader of dugong research in Australia and worldwide; O'shea as a former leader of the United States government's Sirenia Project in Gainesville, Florida; and Reynolds in several roles as a researcher on Florida manatees and other …
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eLS - Sirenia (Dugongs and Manatees)
eLS, 2012Co-Authors: Daryl P. DomningAbstract:Sirenia are an order of large, aquatic, plant-eating, mostly tropical placental mammals that includes the modern seacows (dugongs and manatees) and their extinct relatives. Their nearest living relatives are the Proboscidea (elephants). Together with some extinct orders (including Desmostylia and Embrithopoda), Sirenia and Proboscidea make up a group known as Tethytheria, after their likely origin along the shores of the ancient Tethys Seaway in the Old World. Sirenians first appeared in the fossil record in the Eocene. They comprise four families, two extinct (Prorastomidae and Protosirenidae, both Eocene) and two extant (Trichechidae and Dugongidae). For most of the Tertiary, they formed multispecies communities in marine environments, partitioning seagrass resources in ways not completely understood. However, global cooling after the middle Miocene, and human predation in the North Pacific, diminished their diversity to only two living genera and four species. Key Concepts: Sirenians are herbivorous, completely aquatic mammals that evolved from land-dwelling ancestors. The closest living relatives of the Sirenia are the Proboscidea (elephants). Sirenians have a fossil record dating from the Eocene. Most Sirenians of the past lived in salt water, and fed on seagrasses (marine flowering plants). The Family Dugongidae was the most diverse and successful family of Sirenians. Several lineages of Sirenians apparently specialised on eating large seagrass rhizomes, using bladelike, self-sharpening upper tusks. These specialised Sirenians could act as ‘keystone species’, allowing both seagrasses and other kinds of Sirenians to become locally more diverse. Unlike today, Sirenians of the past formed communities of several coexisting species, with a different taxonomic makeup in each ocean basin. Diversity of Sirenians diminished after the middle Miocene, due to global cooling. Manatees in the southeastern U.S. and Caribbean had a complicated history during the Pleistocene Ice Ages, shifting their range south and north with the alternating glacial and interglacial cycles. Keywords: dugongs; ecology; evolution; manatees; seacows
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Iterative Evolution of Sympatric Seacow (Dugongidae, Sirenia) Assemblages during the Past ~26 Million Years
PloS one, 2012Co-Authors: Jorge Vélez-juarbe, Daryl P. Domning, Nicholas D. PyensonAbstract:Extant Sirenians show allopatric distributions throughout most of their range. However, their fossil record shows evidence of multispecies communities throughout most of the past ∼26 million years, in different oceanic basins. Morphological differences among co-occurring Sirenian taxa suggest that resource partitioning played a role in structuring these communities. We examined body size and ecomorphological differences (e.g., rostral deflection and tusk morphology) among Sirenian assemblages from the late Oligocene of Florida, early Miocene of India and early Pliocene of Mexico; each with three species of the family Dugongidae. Although overlapping in several ecomorphological traits, each assemblage showed at least one dominant trait in which coexisting species differed. Fossil Sirenian occurrences occasionally are monotypic, but the assemblages analyzed herein show iterative evolution of multispecies communities, a phenomenon unparalleled in extant Sirenian ecology. As primary consumers of seagrasses, these communities likely had a strong impact on past seagrass ecology and diversity, although the sparse fossil record of seagrasses limits direct comparisons. Nonetheless, our results provide robust support for previous suggestions that some Sirenians in these extinct assemblages served as keystone species, controlling the dominance of climax seagrass species, permitting more taxonomically diverse seagrass beds (and Sirenian communities) than many of those observed today.
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Evolution of Sirenian Pachyosteosclerosis, a Model-case for the Study of Bone Structure in Aquatic Tetrapods
Journal of Mammalian Evolution, 2010Co-Authors: Vivian Buffrénil, Aurore Canoville, Ruggero D’anastasio, Daryl P. DomningAbstract:Osteosclerosis, or inner bone compaction, and pachyostosis, or outer hyperplasy of bone cortices (swollen bones), are typical features of tetrapods secondarily adapted to life in water. These peculiarities are spectacularly exemplified by the ribs of extant and extinct Sirenia. Sea cows are thus the best model for studying this kind of bone structural specializations. In order to document how these features differentiated during Sirenian evolution, the ribs of 15 species, from the most basal form ( Pezosiren portelli ) up to extant taxa, were studied, and compared to those of other mammalian species from both morphometric and histological points of view. Pachyostosis was the first of these two specializations to occur, by the middle of the Eocene, and is a basal feature of the Sirenia. However, it subsequently regressed in some taxa that do not exhibit hyperplasic rib cortices. Osteosclerosis was only incipient in P . portelli . Its full development occurred later, by the end of the Eocene. These two structural specializations of bone are variably pronounced in extinct and extant Sirenians, and relatively independent from each other, although frequently associated. They are possibly due to similar heterochronic mechanisms bearing on the timing of osteoblast activity. These results are discussed with respect to the functional constraints of locomotion in water.
Ainara Badiola - One of the best experts on this subject based on the ideXlab platform.
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The Hind Limbs of Sobrarbesiren cardieli (Eocene, Northeastern Spain) and New Insights into the Locomotion Capabilities of the Quadrupedal Sirenians
Journal of Mammalian Evolution, 2019Co-Authors: Ester Díaz-berenguer, Ainara Badiola, Alexandra Houssaye, José Ignacio CanudoAbstract:In the transition from a terrestrial to an aquatic environment, Sirenian marine mammals reduced and lost their hind limbs and developed a horizontal caudal fin, the main propulsive organ in extant Sirenians. Quadrupedal forms are only known from the Eocene and are represented by three different clades: the amphibious “prorastomids,” the aquatic quadrupedal protosirenids, and Sobrarbesiren cardieli , a four-legged Sirenian from the middle Eocene of Spain, considered the sister taxon of the fully aquatic Dugongidae. This ecological shift from terrestrial to an aquatic environment was naturally associated with adaptations, among others, of the skeleton. However, Sirenian hind limb bones have been poorly studied because of the scarce material available in the fossil record. Here, we describe in detail the hind limb bones of Sobrarbesiren , analyzing their functional morphology and comparing them with other basal Sirenians and cetaceans, and with related terrestrial mammals such as proboscideans and hyracoids. The hind limbs of Sobrarbesiren were capable of a great variety of movements. Based on the presence of a strong sacroiliac articulation, we propose that it swam by dorsoventral pelvic undulation combined with pelvic paddling analogous to extant otters and the “prorastomid” Pezosiren . We also conduct the first microanatomical analysis of hind limb bones of an Eocene Sirenian. Data reveal extreme inner compactness in the Sobrarbesiren innominate and femur, with the first description of osteosclerosis in an amniote innominate combined with the highest degree of osteosclerosis observed in amniote femora. The results confirm that the microanatomical changes precede the external morphological changes in such ecological transitions. The process of adaptation of Sirenians to an aquatic life was thus a more complex process than previously thought.
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The Hind Limbs of Sobrarbesiren cardieli (Eocene, Northeastern Spain) and New Insights into the Locomotion Capabilities of the Quadrupedal Sirenians
Journal of Mammalian Evolution, 2019Co-Authors: Ester Díaz-berenguer, Ainara Badiola, Alexandra Houssaye, José Ignacio CanudoAbstract:In the transition from a terrestrial to an aquatic environment, Sirenian marine mammals reduced and lost their hindlimbs and developed a horizontal tail, the main propulsive organ in extant Sirenians. Quadrupedal forms are only known from the Eocene and are represented by three different taxa: the amphibious prorastomids, the aquatic quadrupedal protosirenids and Sobrarbesiren cardieli, a four-legged Sirenian from the middle Eocene of Spain, considered the sister taxon of the aquatic Dugongidae. This ecological shift was naturally associated with adaptations, among others, of the skeleton. However, Sirenian hindlimb bones have been poorly studied because of the scarce material available in the fossil record. Here we describe in detail the hindlimb bones of Sobrarbesiren, analyzing their functional morphology and comparing them with other basal Sirenians and cetaceans. Sobrarbesiren had strong control of its hindlimbs, which were capable of a great variety of movements. Based on the presence of a strong sacroiliac articulation, we propose that it swam by dorsoventral pelvic undulation combined with pelvic paddling analogous to some protocetid archaeocete whales. We also conducted the first microanatomical analysis of hindlimb bones of an Eocene Sirenian. Data reveal extreme inner compactness in the Sobrarbesiren innominate bone and femur, with the first description of 2 osteosclerosis in an amniote innominate bone combined with the highest degree of osteosclerosis observed in amniote femora. The results confirm that the microanatomical changes precede the external morphological changes in such ecological transitions. The process of adaptation of Sirenians to an aquatic life was thus a more complex process than previously thought.
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First adequately-known quadrupedal Sirenian from Eurasia (Eocene, Bay of Biscay, Huesca, northeastern Spain).
Scientific reports, 2018Co-Authors: Ester Díaz-berenguer, Ainara Badiola, Miguel Moreno-azanza, José Ignacio CanudoAbstract:Sirenians are the only extant herbivorous mammals fully adapted to an aquatic lifestyle. They originated in Africa during the Paleocene from an undetermined clade of afrotherian mammals, and by the end of the Eocene they were widely distributed across the tropical latitudes. Here we introduce Sobrarbesiren cardieli gen. et sp. nov. It is the first adequately-known quadrupedal Sirenian from Eurasia and the oldest record of this clade from western Europe. Fossils have been recovered from the middle Lutetian (SBZ15) site of Castejon de Sobrarbe-41 (Huesca, Spain), and comprise many cranial and postcranial remains, including pelvic girdle and hind limb bones, from at least six Sirenian individuals of different ontogenetic stages. Sobrarbesiren shows a suite of characters previously considered synapomorphies of different clades of derived Sirenians, such as the presence of the processus retroversus of the squamosal and the pterygoid fossa, combined with ancestral characters such as the presence of an alisphenoid canal, a permanent P5, at least two sacral vertebrae, a primitive pelvis and functional femora and fibulae. Sobrarbesiren is recovered as the sister taxon of Dugongidae and represents a transitional stage of adaptation to aquatic life between the amphibious quadrupedal prorastomids and the aquatic quadrupedal protosirenids.
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New fossils of Sirenia from the Middle Eocene of Navarre (Western Pyrenees): the oldest West European sea cow record
Geological Magazine, 2010Co-Authors: Humberto Astibia, Nathalie Bardet, Xabier Pereda-suberbiola, Aitor Payros, V. De Buffrénil, Javier Elorza, Josep Tosquella, Ana Berreteaga, Ainara BadiolaAbstract:Postcranial remains of Sirenia from the early Middle Eocene (late Lutetian) Urbasa-Andia Formation of Navarre (Western Pyrenees) are described. The material consists of two partial atlas vertebrae, one humerus and several dorsal ribs (from Arrasate, Urbasa plateau), and partial dorsal ribs (from Lezaun, Andia plateau). The morphology of the fossils is consistent with referral to Dugongidae, the only Sirenian clade known so far in the Middle Eocene of Europe. Moreover, the histological study of the ribs shows that the pachyosteosclerosis of extant Sirenia was definitively present by the early Middle Eocene. The oldest Sirenian remains reported to date in the Pyrenean Realm were assigned to the Biarritzian, a regional stage that is currently ascribed either to the middle or to the lower–middle Bartonian. Therefore, the Sirenian remains of Lezaun, reliably dated as late Lutetian (SBZ16 zone) in age, are definitively the earliest Sirenian fossils known in Western Europe and are among the oldest sea cow records of Europe.
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Sedimentology and taphonomy of Sirenian remains from the Middle Eocene of the Pamplona Basin (Navarre, western Pyrenees)
Facies, 2005Co-Authors: Humberto Astibia, Ainara Badiola, Aitor Payros, Javier Elorza, Ana Berreteaga, Xabier Pereda Suberbiola, Nestor Etxebarria, Josep TosquellaAbstract:Sirenian vertebrae and ribs have been recently discovered from two Middle Eocene localities of the Pamplona Basin, Navarre (western Pyrenees). These outcrops correspond to different lower Bartonian lithostratigraphic units: the lower part of the Pamplona Marl Formation (Uztarrotz site) and the upper part of the Ardanatz Sandstone (Ardanatz site). The former represents a deep and low-energy sea floor far away from a deltaic slope; the Ardanatz environment probably corresponds to a semi-closed deltaic bay periodically affected by catastrophic floods (i.e., fluvial hyperpycnal flows). The presence of epibiontic activity suggests that the bones were exposed for a while prior to the burial. The histological structures are well preserved except in the peripheral region, where tubular-like microstructures filled by pyrite and iron oxides probably correspond to microbial bioerosion. The major mineral component of the fossil bones is francolite (carbonate fluorapatite). In the Ardanatz samples there is evidence of secondary francolite due to the late replacement of original carbonate fluorapatite through internal fractures. The Ardanatz and Uztarrotz Sirenian fossils do not show any evidence of reelaboration. They have similar sum of rare earth elements (REE) concentrations relative to the host rock, but comparatively lower than in other vertebrate fossil bones. This feature may be due to the dense compact structure of pachyosteosclerotic Sirenian bones.
Roger L. Reep - One of the best experts on this subject based on the ideXlab platform.
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elaboration and innervation of the vibrissal system in the rock hyrax procavia capensis
Brain Behavior and Evolution, 2015Co-Authors: Diana K Sarko, Frank L. Rice, Roger L. ReepAbstract:Mammalian tactile hairs are commonly found on specific, restricted regions of the body, but Florida manatees represent a unique exception, exhibiting follicle-sinus complexes (FSCs, also known as vibrissae or tactile hairs) on their entire body. The orders Sirenia (including manatees and dugongs) and Hyracoidea (hyraxes) are thought to have diverged approximately 60 million years ago, yet hyraxes are among the closest relatives to Sirenians. We investigated the possibility that hyraxes, like manatees, are tactile specialists with vibrissae that cover the entire postfacial body. Previous studies suggested that rock hyraxes possess postfacial vibrissae in addition to pelage hair, but this observation was not verified through histological examination. Using a detailed immunohistochemical analysis, we characterized the gross morphology, innervation and mechanoreceptors present in FSCs sampled from facial and postfacial vibrissae body regions to determine that the long postfacial hairs on the hyrax body are in fact true vibrissae. The types and relative densities of mechanoreceptors associated with each FSC also appeared to be relatively consistent between facial and postfacial FSCs. The presence of vibrissae covering the hyrax body presumably facilitates navigation in the dark caves and rocky crevices of the hyrax's environment where visual cues are limited, and may alert the animal to predatory or conspecific threats approaching the body. Furthermore, the presence of vibrissae on the postfacial body in both manatees and hyraxes indicates that this distribution may represent the ancestral condition for the supraorder Paenungulata.
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Estimating body size of fossil Sirenians
Marine Mammal Science, 2010Co-Authors: Diana K Sarko, Daryl P. Domning, Lori Marino, Roger L. ReepAbstract:Estimates of fossil Sirenian body size are important for understanding niche partitioning among possibly sympatric species. Because of the paucity of complete fossil skeletons, we explored the utility of three morphometric predictors of body size: (condylobasal skull length [BSL]; occipital condyle width [OCW]; and foramen magnum width [FMW]) in extant Sirenians—Florida manatees (Trichechus manatus latirostris) and dugongs (Dugong dugon)—and then applied these to obtain estimates of body size in extinct Sirenian taxa. Condylobasal length of the skull is a more accurate predictor of body size in extant Florida manatees and dugongs than are width of the occipital condyles or width of the foramen magnum. Body length (BL) is predicted more accurately than is body weight (BW) for all three morphometric predictors. For our sample of fossil Sirenians, BSL, OCW, and FMW were used to generate predicted BLs and BWs. Preliminary assessments of fossil Sirenian faunas from Florida and India suggest that body mass could have been one of several possible important morphological parameters accounting for feeding niche separation.
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digesta passage rates in the florida manatee trichechus manatus latirostris
Zoo Biology, 2007Co-Authors: Iskande L V Larkin, Vivienne F Fowler, Roger L. ReepAbstract:The Florida manatee, Trichechus manatus latirostris (Sirenia: Trichechidae), is an herbivorous marine mammal found within coastal areas throughout the state of Florida, which feeds on both fresh and salt water sea grasses. Manatees, like other Sirenians, are a tropical species with little tolerance for water temperatures below 20°C, rely on a relatively poor nutritional food source, and have a low metabolic rate. Although manatees are hindgut fermenting herbivores, they are very efficient at extracting nutrients from the plants on which they feed. Slow passage rates of digesta have been suggested to be a factor in this increased efficiency. Two studies monitored the digesta passage times and mixing of particulate digesta within the manatee digestive tract using MicroGrits colored corncob grit as a fecal marker. Fecal samples were collected subsequently from four manatees in Study 1 and 3 manatees in Study 2, grit pieces removed, counted, and measured. The digesta passage times ranged from 6 and 10 days in Study 1, and 4.3 and 8.3 days in Study 2, supporting data presented in previous studies. When two different colored markers were administered on sequential days, minimal to no mixing was seen in recovered feces, suggesting that the digesta from a given day traveled through the tract as a bolus. Less than 1% of the marker fed was recovered and we hypothesize that perpendicular folds of the large intestine may be the major contributing factor, with pieces being retained and eventually digested. Zoo Biol 26:503–515, 2007. © 2007 Wiley-Liss, Inc.
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Orofacial morphology and feeding behaviour of the dugong, Amazonian, West African and Antillean manatees (Mammalia: Sirenia): functional morphology of the muscular-vibrissal complex
Journal of Zoology, 2003Co-Authors: Christopher D. Marshall, Fernando C. W. Rosas, Hiroshi Maeda, Matsumitsu Iwata, Masami Furuta, Shiro Asano, Roger L. ReepAbstract:The external orofacial morphology, perioral bristle distribution and feeding behaviour of Dugong dugon, Trichechus inunguis, T. senegalensis and T. manatus are described. Despite their differing orofacial morphology, dugongs and trichechids possess six similar regions: the oral disk, orofacial ridge, supradisk, chin and upper and lower bristle (modified vibrissae) pads. All living Sirenians possess six discrete fields of bristles: four on the upper lip (U1, U2, U3, and U4) and two on the lower lip (L1 and L2). The distribution of these fields is similar among all living Sirenians with the exception of the U1 bristle fields in dugongs. Perioral bristle field boundaries are distinguished by distinct changes in their length-to-diameter ratios. Both dugongs and trichechids possess bristle-like hairs covering the oral disk, which possess length-to-diameter ratios intermediate between perioral bristles and postcranial hairs. Sirenians use elaborated facial musculature in conjunction with perioral bristles to acquire, manipulate and ingest aquatic vegetation. The U2 and L1 fields are the primary bristles used to ingest vegetation. The use of the L1 bristle fields is similar among all living Sirenians. However, dugongs and trichechids are divergent in their use of the U1 and U2 bristle fields. Dugongs use the U2 bristles fields in a medial-to-lateral motion, while all trichechids use the U2 bristles in a prehensile, lateral-to-medial, grasping motion. These divergent behaviours presumably allow dugongs to exploit benthic foraging (i.e. consumption of rhizomes) to a greater degree than trichechids. Functional hypotheses of rhizome excavation are presented for both dugongs and trichechids.
José Ignacio Canudo - One of the best experts on this subject based on the ideXlab platform.
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The Hind Limbs of Sobrarbesiren cardieli (Eocene, Northeastern Spain) and New Insights into the Locomotion Capabilities of the Quadrupedal Sirenians
Journal of Mammalian Evolution, 2019Co-Authors: Ester Díaz-berenguer, Ainara Badiola, Alexandra Houssaye, José Ignacio CanudoAbstract:In the transition from a terrestrial to an aquatic environment, Sirenian marine mammals reduced and lost their hind limbs and developed a horizontal caudal fin, the main propulsive organ in extant Sirenians. Quadrupedal forms are only known from the Eocene and are represented by three different clades: the amphibious “prorastomids,” the aquatic quadrupedal protosirenids, and Sobrarbesiren cardieli , a four-legged Sirenian from the middle Eocene of Spain, considered the sister taxon of the fully aquatic Dugongidae. This ecological shift from terrestrial to an aquatic environment was naturally associated with adaptations, among others, of the skeleton. However, Sirenian hind limb bones have been poorly studied because of the scarce material available in the fossil record. Here, we describe in detail the hind limb bones of Sobrarbesiren , analyzing their functional morphology and comparing them with other basal Sirenians and cetaceans, and with related terrestrial mammals such as proboscideans and hyracoids. The hind limbs of Sobrarbesiren were capable of a great variety of movements. Based on the presence of a strong sacroiliac articulation, we propose that it swam by dorsoventral pelvic undulation combined with pelvic paddling analogous to extant otters and the “prorastomid” Pezosiren . We also conduct the first microanatomical analysis of hind limb bones of an Eocene Sirenian. Data reveal extreme inner compactness in the Sobrarbesiren innominate and femur, with the first description of osteosclerosis in an amniote innominate combined with the highest degree of osteosclerosis observed in amniote femora. The results confirm that the microanatomical changes precede the external morphological changes in such ecological transitions. The process of adaptation of Sirenians to an aquatic life was thus a more complex process than previously thought.
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The Hind Limbs of Sobrarbesiren cardieli (Eocene, Northeastern Spain) and New Insights into the Locomotion Capabilities of the Quadrupedal Sirenians
Journal of Mammalian Evolution, 2019Co-Authors: Ester Díaz-berenguer, Ainara Badiola, Alexandra Houssaye, José Ignacio CanudoAbstract:In the transition from a terrestrial to an aquatic environment, Sirenian marine mammals reduced and lost their hindlimbs and developed a horizontal tail, the main propulsive organ in extant Sirenians. Quadrupedal forms are only known from the Eocene and are represented by three different taxa: the amphibious prorastomids, the aquatic quadrupedal protosirenids and Sobrarbesiren cardieli, a four-legged Sirenian from the middle Eocene of Spain, considered the sister taxon of the aquatic Dugongidae. This ecological shift was naturally associated with adaptations, among others, of the skeleton. However, Sirenian hindlimb bones have been poorly studied because of the scarce material available in the fossil record. Here we describe in detail the hindlimb bones of Sobrarbesiren, analyzing their functional morphology and comparing them with other basal Sirenians and cetaceans. Sobrarbesiren had strong control of its hindlimbs, which were capable of a great variety of movements. Based on the presence of a strong sacroiliac articulation, we propose that it swam by dorsoventral pelvic undulation combined with pelvic paddling analogous to some protocetid archaeocete whales. We also conducted the first microanatomical analysis of hindlimb bones of an Eocene Sirenian. Data reveal extreme inner compactness in the Sobrarbesiren innominate bone and femur, with the first description of 2 osteosclerosis in an amniote innominate bone combined with the highest degree of osteosclerosis observed in amniote femora. The results confirm that the microanatomical changes precede the external morphological changes in such ecological transitions. The process of adaptation of Sirenians to an aquatic life was thus a more complex process than previously thought.
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First adequately-known quadrupedal Sirenian from Eurasia (Eocene, Bay of Biscay, Huesca, northeastern Spain).
Scientific reports, 2018Co-Authors: Ester Díaz-berenguer, Ainara Badiola, Miguel Moreno-azanza, José Ignacio CanudoAbstract:Sirenians are the only extant herbivorous mammals fully adapted to an aquatic lifestyle. They originated in Africa during the Paleocene from an undetermined clade of afrotherian mammals, and by the end of the Eocene they were widely distributed across the tropical latitudes. Here we introduce Sobrarbesiren cardieli gen. et sp. nov. It is the first adequately-known quadrupedal Sirenian from Eurasia and the oldest record of this clade from western Europe. Fossils have been recovered from the middle Lutetian (SBZ15) site of Castejon de Sobrarbe-41 (Huesca, Spain), and comprise many cranial and postcranial remains, including pelvic girdle and hind limb bones, from at least six Sirenian individuals of different ontogenetic stages. Sobrarbesiren shows a suite of characters previously considered synapomorphies of different clades of derived Sirenians, such as the presence of the processus retroversus of the squamosal and the pterygoid fossa, combined with ancestral characters such as the presence of an alisphenoid canal, a permanent P5, at least two sacral vertebrae, a primitive pelvis and functional femora and fibulae. Sobrarbesiren is recovered as the sister taxon of Dugongidae and represents a transitional stage of adaptation to aquatic life between the amphibious quadrupedal prorastomids and the aquatic quadrupedal protosirenids.
Maria Paula Cruz Schneider - One of the best experts on this subject based on the ideXlab platform.
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Data_Sheet_2_The Marine Mammal Class II Major Histocompatibility Complex Organization.FASTA
2019Co-Authors: Breanna Breaux, Tibério Cesar Tortola Burlamaqui, Thaddeus Charles Deiss, Leonardo Sena, Michael Frederick Criscitiello, Maria Paula Cruz SchneiderAbstract:Sirenians share with cetaceans and pinnipeds several convergent traits selected for the aquatic lifestyle. Living in water poses new challenges not only for locomotion and feeding but also for combating new pathogens, which may render the immune system one of the best tools aquatic mammals have for dealing with aquatic microbial threats. So far, only cetaceans have had their class II Major Histocompatibility Complex (MHC) organization characterized, despite the importance of MHC genes for adaptive immune responses. This study aims to characterize the organization of the marine mammal class II MHC using publicly available genomes. We located class II sequences in the genomes of one Sirenian, four pinnipeds and eight cetaceans using NCBI-BLAST and reannotated the sequences using local BLAST search with exon and intron libraries. Scaffolds containing class II sequences were compared using dotplot analysis and introns were used for phylogenetic analysis. The manatee class II region shares overall synteny with other mammals, however most DR loci were translocated from the canonical location, past the extended class II region. Detailed analysis of the genomes of closely related taxa revealed that this presumed translocation is shared with all other living afrotherians. Other presumptive chromosome rearrangements in Afrotheria are the deletion of DQ loci in Afrosoricida and deletion of DP in E. telfairi. Pinnipeds share the main features of dog MHC: lack of a functional pair of DPA/DPB genes and inverted DRB locus between DQ and DO subregions. All cetaceans share the Cetartiodactyla inversion separating class II genes into two subregions: class IIa, with DR and DQ genes, and class IIb, with non-classic genes and a DRB pseudogene. These results point to three distinct and unheralded class II MHC structures in marine mammals: one canonical organization but lacking DP genes in pinnipeds; one bearing an inversion separating IIa and IIb subregions lacking DP genes found in cetaceans; and one with a translocation separating the most diverse class II gene from the MHC found in afrotherians and presumptive functional DR, DQ, and DP genes. Future functional research will reveal how these aquatic mammals cope with pathogen pressures with these divergent MHC organizations.
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Data_Sheet_1_The Marine Mammal Class II Major Histocompatibility Complex Organization.ZIP
2019Co-Authors: Breanna Breaux, Tibério Cesar Tortola Burlamaqui, Thaddeus Charles Deiss, Leonardo Sena, Michael Frederick Criscitiello, Maria Paula Cruz SchneiderAbstract:Sirenians share with cetaceans and pinnipeds several convergent traits selected for the aquatic lifestyle. Living in water poses new challenges not only for locomotion and feeding but also for combating new pathogens, which may render the immune system one of the best tools aquatic mammals have for dealing with aquatic microbial threats. So far, only cetaceans have had their class II Major Histocompatibility Complex (MHC) organization characterized, despite the importance of MHC genes for adaptive immune responses. This study aims to characterize the organization of the marine mammal class II MHC using publicly available genomes. We located class II sequences in the genomes of one Sirenian, four pinnipeds and eight cetaceans using NCBI-BLAST and reannotated the sequences using local BLAST search with exon and intron libraries. Scaffolds containing class II sequences were compared using dotplot analysis and introns were used for phylogenetic analysis. The manatee class II region shares overall synteny with other mammals, however most DR loci were translocated from the canonical location, past the extended class II region. Detailed analysis of the genomes of closely related taxa revealed that this presumed translocation is shared with all other living afrotherians. Other presumptive chromosome rearrangements in Afrotheria are the deletion of DQ loci in Afrosoricida and deletion of DP in E. telfairi. Pinnipeds share the main features of dog MHC: lack of a functional pair of DPA/DPB genes and inverted DRB locus between DQ and DO subregions. All cetaceans share the Cetartiodactyla inversion separating class II genes into two subregions: class IIa, with DR and DQ genes, and class IIb, with non-classic genes and a DRB pseudogene. These results point to three distinct and unheralded class II MHC structures in marine mammals: one canonical organization but lacking DP genes in pinnipeds; one bearing an inversion separating IIa and IIb subregions lacking DP genes found in cetaceans; and one with a translocation separating the most diverse class II gene from the MHC found in afrotherians and presumptive functional DR, DQ, and DP genes. Future functional research will reveal how these aquatic mammals cope with pathogen pressures with these divergent MHC organizations.
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Table_2_The Marine Mammal Class II Major Histocompatibility Complex Organization.XLSX
2019Co-Authors: Breanna Breaux, Tibério Cesar Tortola Burlamaqui, Thaddeus Charles Deiss, Leonardo Sena, Michael Frederick Criscitiello, Maria Paula Cruz SchneiderAbstract:Sirenians share with cetaceans and pinnipeds several convergent traits selected for the aquatic lifestyle. Living in water poses new challenges not only for locomotion and feeding but also for combating new pathogens, which may render the immune system one of the best tools aquatic mammals have for dealing with aquatic microbial threats. So far, only cetaceans have had their class II Major Histocompatibility Complex (MHC) organization characterized, despite the importance of MHC genes for adaptive immune responses. This study aims to characterize the organization of the marine mammal class II MHC using publicly available genomes. We located class II sequences in the genomes of one Sirenian, four pinnipeds and eight cetaceans using NCBI-BLAST and reannotated the sequences using local BLAST search with exon and intron libraries. Scaffolds containing class II sequences were compared using dotplot analysis and introns were used for phylogenetic analysis. The manatee class II region shares overall synteny with other mammals, however most DR loci were translocated from the canonical location, past the extended class II region. Detailed analysis of the genomes of closely related taxa revealed that this presumed translocation is shared with all other living afrotherians. Other presumptive chromosome rearrangements in Afrotheria are the deletion of DQ loci in Afrosoricida and deletion of DP in E. telfairi. Pinnipeds share the main features of dog MHC: lack of a functional pair of DPA/DPB genes and inverted DRB locus between DQ and DO subregions. All cetaceans share the Cetartiodactyla inversion separating class II genes into two subregions: class IIa, with DR and DQ genes, and class IIb, with non-classic genes and a DRB pseudogene. These results point to three distinct and unheralded class II MHC structures in marine mammals: one canonical organization but lacking DP genes in pinnipeds; one bearing an inversion separating IIa and IIb subregions lacking DP genes found in cetaceans; and one with a translocation separating the most diverse class II gene from the MHC found in afrotherians and presumptive functional DR, DQ, and DP genes. Future functional research will reveal how these aquatic mammals cope with pathogen pressures with these divergent MHC organizations.
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The Marine Mammal Class II Major Histocompatibility Complex Organization
Frontiers Media S.A., 2019Co-Authors: Breanna Breaux, Tibério Cesar Tortola Burlamaqui, Thaddeus Charles Deiss, Leonardo Sena, Michael Frederick Criscitiello, Maria Paula Cruz SchneiderAbstract:Sirenians share with cetaceans and pinnipeds several convergent traits selected for the aquatic lifestyle. Living in water poses new challenges not only for locomotion and feeding but also for combating new pathogens, which may render the immune system one of the best tools aquatic mammals have for dealing with aquatic microbial threats. So far, only cetaceans have had their class II Major Histocompatibility Complex (MHC) organization characterized, despite the importance of MHC genes for adaptive immune responses. This study aims to characterize the organization of the marine mammal class II MHC using publicly available genomes. We located class II sequences in the genomes of one Sirenian, four pinnipeds and eight cetaceans using NCBI-BLAST and reannotated the sequences using local BLAST search with exon and intron libraries. Scaffolds containing class II sequences were compared using dotplot analysis and introns were used for phylogenetic analysis. The manatee class II region shares overall synteny with other mammals, however most DR loci were translocated from the canonical location, past the extended class II region. Detailed analysis of the genomes of closely related taxa revealed that this presumed translocation is shared with all other living afrotherians. Other presumptive chromosome rearrangements in Afrotheria are the deletion of DQ loci in Afrosoricida and deletion of DP in E. telfairi. Pinnipeds share the main features of dog MHC: lack of a functional pair of DPA/DPB genes and inverted DRB locus between DQ and DO subregions. All cetaceans share the Cetartiodactyla inversion separating class II genes into two subregions: class IIa, with DR and DQ genes, and class IIb, with non-classic genes and a DRB pseudogene. These results point to three distinct and unheralded class II MHC structures in marine mammals: one canonical organization but lacking DP genes in pinnipeds; one bearing an inversion separating IIa and IIb subregions lacking DP genes found in cetaceans; and one with a translocation separating the most diverse class II gene from the MHC found in afrotherians and presumptive functional DR, DQ, and DP genes. Future functional research will reveal how these aquatic mammals cope with pathogen pressures with these divergent MHC organizations
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Data_Sheet_11_The Marine Mammal Class II Major Histocompatibility Complex Organization.FASTA
2019Co-Authors: Breanna Breaux, Tibério Cesar Tortola Burlamaqui, Thaddeus Charles Deiss, Leonardo Sena, Michael Frederick Criscitiello, Maria Paula Cruz SchneiderAbstract:Sirenians share with cetaceans and pinnipeds several convergent traits selected for the aquatic lifestyle. Living in water poses new challenges not only for locomotion and feeding but also for combating new pathogens, which may render the immune system one of the best tools aquatic mammals have for dealing with aquatic microbial threats. So far, only cetaceans have had their class II Major Histocompatibility Complex (MHC) organization characterized, despite the importance of MHC genes for adaptive immune responses. This study aims to characterize the organization of the marine mammal class II MHC using publicly available genomes. We located class II sequences in the genomes of one Sirenian, four pinnipeds and eight cetaceans using NCBI-BLAST and reannotated the sequences using local BLAST search with exon and intron libraries. Scaffolds containing class II sequences were compared using dotplot analysis and introns were used for phylogenetic analysis. The manatee class II region shares overall synteny with other mammals, however most DR loci were translocated from the canonical location, past the extended class II region. Detailed analysis of the genomes of closely related taxa revealed that this presumed translocation is shared with all other living afrotherians. Other presumptive chromosome rearrangements in Afrotheria are the deletion of DQ loci in Afrosoricida and deletion of DP in E. telfairi. Pinnipeds share the main features of dog MHC: lack of a functional pair of DPA/DPB genes and inverted DRB locus between DQ and DO subregions. All cetaceans share the Cetartiodactyla inversion separating class II genes into two subregions: class IIa, with DR and DQ genes, and class IIb, with non-classic genes and a DRB pseudogene. These results point to three distinct and unheralded class II MHC structures in marine mammals: one canonical organization but lacking DP genes in pinnipeds; one bearing an inversion separating IIa and IIb subregions lacking DP genes found in cetaceans; and one with a translocation separating the most diverse class II gene from the MHC found in afrotherians and presumptive functional DR, DQ, and DP genes. Future functional research will reveal how these aquatic mammals cope with pathogen pressures with these divergent MHC organizations.