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Jean-renaud Boisserie - One of the best experts on this subject based on the ideXlab platform.
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Basal hippopotamines from the upper Miocene of Chorora, Ethiopia
Journal of Vertebrate Paleontology, 2017Co-Authors: Jean-renaud Boisserie, Fabrice Lihoreau, Suwa, Berhane Asfaw, Raymond L. Bernor, Shigehiro Katoh, Yonas BeyeneAbstract:ABSTRACTThe Hippopotamidae have been a major component of the African wetland fauna for the last 7 million years, following the ‘Hippopotamine Event,’ i.e., the sudden emergence in the fossil record of the subfamily Hippopotaminae, including both extant species. The general dearth of African fossiliferous deposits dated between 9.5 Ma and 7.5 Ma concealed until now the evolution that led to the Hippopotamine Event and the subsequent success of these large semiaquatic herbivores. Part of this evolution is unveiled by the hippopotamid dental remains found at Chorora, a late Miocene site of the southern Afar Depression in Ethiopia spanning most of the fossil-depleted time interval. Although fragmentary, these remains represent a new, mid-sized hippopotamid species dated to ca. 8 Ma, as well as a somewhat younger, larger form. A cladistic analysis of a large array of cetartiodactyls indicates that the Chorora taxa were basal to the latest Miocene hippopotamines. The new species displays a mosaic of dental cha...
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Middle Miocene Kenyapotamus (Cetartiodactyla, Hippopotamidae) from Napudet, Turkana Basin, Kenya
Journal of Vertebrate Paleontology, 2017Co-Authors: Jean-renaud Boisserie, Fabrice Lihoreau, Christopher Kiarie, Isaiah NengoAbstract:ABSTRACTWe describe five new specimens of Hippopotamidae from the Miocene of Napudet, a new site in southwestern Turkana Basin, Kenya. These specimens include fragmentary maxillae with teeth and a well-preserved mandibular symphysis. We attribute them to Kenyapotamus ternani, the least known species within Kenyapotamus, on the basis of relatively small dental dimensions and a clear distinction between the parastyle and the mesiostyle on the upper molars. This attribution suggests an age older than 10 Ma for Napudet. A cladistic analysis integrating these new data makes it possible to evaluate the relationships between middle Miocene hippopotamids and later representatives. The mandibular symphysis from Napudet, defining the plesiomorphic condition for mandibular morphology in Hippopotaminae, could be crucial for future phylogenetic reconstructions of the family. Mandibular morphology is a fast-evolving complex of characters, key in reconstructing the behavior and the past diversity of Hippopotamidae. Fina...
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Middle Miocene Kenyapotamus (Cetartiodactyla, Hippopotamidae) from Napudet, Turkana Basin, Kenya
2017Co-Authors: Jean-renaud Boisserie, Fabrice Lihoreau, Christopher Kiarie, Isaiah NengoAbstract:We describe five new specimens of Hippopotamidae from the Miocene of Napudet, a new site in southwestern Turkana Basin, Kenya. These specimens include fragmentary maxillae with teeth and a well-preserved mandibular symphysis. We attribute them to Kenyapotamus ternani, the least known species within Kenyapotamus, on the basis of relatively small dental dimensions and a clear distinction between the parastyle and the mesiostyle on the upper molars. This attribution suggests an age older than 10 Ma for Napudet. A cladistic analysis integrating these new data makes it possible to evaluate the relationships between middle Miocene hippopotamids and later representatives. The mandibular symphysis from Napudet, defining the plesiomorphic condition for mandibular morphology in Hippopotaminae, could be crucial for future phylogenetic reconstructions of the family. Mandibular morphology is a fast-evolving complex of characters, key in reconstructing the behavior and the past diversity of Hippopotamidae. Finally, this material demonstrates the potential of Napudet for augmenting the fossil record for a relatively ill-documented time interval (13–10 Ma). SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Boisserie, J.-R., C. Kiarie, F. Lihoreau, and I. Nengo. 2017. Middle Miocene Kenyapotamus (Cetartiodactyla, Hippopotamidae) from Napudet, Turkana Basin, Kenya. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1272055.
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Basal hippopotamines from the upper Miocene of Chorora, Ethiopia
2017Co-Authors: Jean-renaud Boisserie, Fabrice Lihoreau, Berhane Asfaw, Raymond L. Bernor, Shigehiro Katoh, Gen Suwa, Yonas BeyeneAbstract:The Hippopotamidae have been a major component of the African wetland fauna for the last 7 million years, following the ‘Hippopotamine Event,’ i.e., the sudden emergence in the fossil record of the subfamily Hippopotaminae, including both extant species. The general dearth of African fossiliferous deposits dated between 9.5 Ma and 7.5 Ma concealed until now the evolution that led to the Hippopotamine Event and the subsequent success of these large semiaquatic herbivores. Part of this evolution is unveiled by the hippopotamid dental remains found at Chorora, a late Miocene site of the southern Afar Depression in Ethiopia spanning most of the fossil-depleted time interval. Although fragmentary, these remains represent a new, mid-sized hippopotamid species dated to ca. 8 Ma, as well as a somewhat younger, larger form. A cladistic analysis of a large array of cetartiodactyls indicates that the Chorora taxa were basal to the latest Miocene hippopotamines. The new species displays a mosaic of dental characters that support the attribution of the new species to a new genus within Hippopotaminae. The new fossils also clarify the course of early hippopotamine dental evolution. The Chorora hippopotamids suggest that transition to a marked abundance of hippopotamines with their unique dental pattern in African ecosystems occurred within a relatively short time interval, most probably between 8 Ma and 7.5 Ma. http://zoobank.org/urn:lsid:zoobank.org:pub:47B9381F-E3B5-40C9-B9AB-51CC3D0D3A8A SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Boisserie, J.-R., G. Suwa, B. Asfaw, F. Lihoreau, R. L. Bernor, S. Katoh, and Y. Beyene. 2017. Basal hippopotamines from the upper Miocene of Chorora, Ethiopia. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1297718.
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Hippos stem from the longest sequence of terrestrial cetartiodactyl evolution in Africa.
Nature Communications, 2015Co-Authors: Fabrice Lihoreau, Jean-renaud Boisserie, Fredrick Manthi, Stephane DucrocqAbstract:The evolutionary origin of Hippopotamidae, the family of hippos, is poorly understood. Here, the authors describe a new fossil from Kenya that unambiguously roots Hippopotamidae into the group that includes the first large terrestrial mammals to invade Africa, more than 30 million years ago.
Fabrice Lihoreau - One of the best experts on this subject based on the ideXlab platform.
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Basal hippopotamines from the upper Miocene of Chorora, Ethiopia
Journal of Vertebrate Paleontology, 2017Co-Authors: Jean-renaud Boisserie, Fabrice Lihoreau, Suwa, Berhane Asfaw, Raymond L. Bernor, Shigehiro Katoh, Yonas BeyeneAbstract:ABSTRACTThe Hippopotamidae have been a major component of the African wetland fauna for the last 7 million years, following the ‘Hippopotamine Event,’ i.e., the sudden emergence in the fossil record of the subfamily Hippopotaminae, including both extant species. The general dearth of African fossiliferous deposits dated between 9.5 Ma and 7.5 Ma concealed until now the evolution that led to the Hippopotamine Event and the subsequent success of these large semiaquatic herbivores. Part of this evolution is unveiled by the hippopotamid dental remains found at Chorora, a late Miocene site of the southern Afar Depression in Ethiopia spanning most of the fossil-depleted time interval. Although fragmentary, these remains represent a new, mid-sized hippopotamid species dated to ca. 8 Ma, as well as a somewhat younger, larger form. A cladistic analysis of a large array of cetartiodactyls indicates that the Chorora taxa were basal to the latest Miocene hippopotamines. The new species displays a mosaic of dental cha...
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Middle Miocene Kenyapotamus (Cetartiodactyla, Hippopotamidae) from Napudet, Turkana Basin, Kenya
Journal of Vertebrate Paleontology, 2017Co-Authors: Jean-renaud Boisserie, Fabrice Lihoreau, Christopher Kiarie, Isaiah NengoAbstract:ABSTRACTWe describe five new specimens of Hippopotamidae from the Miocene of Napudet, a new site in southwestern Turkana Basin, Kenya. These specimens include fragmentary maxillae with teeth and a well-preserved mandibular symphysis. We attribute them to Kenyapotamus ternani, the least known species within Kenyapotamus, on the basis of relatively small dental dimensions and a clear distinction between the parastyle and the mesiostyle on the upper molars. This attribution suggests an age older than 10 Ma for Napudet. A cladistic analysis integrating these new data makes it possible to evaluate the relationships between middle Miocene hippopotamids and later representatives. The mandibular symphysis from Napudet, defining the plesiomorphic condition for mandibular morphology in Hippopotaminae, could be crucial for future phylogenetic reconstructions of the family. Mandibular morphology is a fast-evolving complex of characters, key in reconstructing the behavior and the past diversity of Hippopotamidae. Fina...
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Middle Miocene Kenyapotamus (Cetartiodactyla, Hippopotamidae) from Napudet, Turkana Basin, Kenya
2017Co-Authors: Jean-renaud Boisserie, Fabrice Lihoreau, Christopher Kiarie, Isaiah NengoAbstract:We describe five new specimens of Hippopotamidae from the Miocene of Napudet, a new site in southwestern Turkana Basin, Kenya. These specimens include fragmentary maxillae with teeth and a well-preserved mandibular symphysis. We attribute them to Kenyapotamus ternani, the least known species within Kenyapotamus, on the basis of relatively small dental dimensions and a clear distinction between the parastyle and the mesiostyle on the upper molars. This attribution suggests an age older than 10 Ma for Napudet. A cladistic analysis integrating these new data makes it possible to evaluate the relationships between middle Miocene hippopotamids and later representatives. The mandibular symphysis from Napudet, defining the plesiomorphic condition for mandibular morphology in Hippopotaminae, could be crucial for future phylogenetic reconstructions of the family. Mandibular morphology is a fast-evolving complex of characters, key in reconstructing the behavior and the past diversity of Hippopotamidae. Finally, this material demonstrates the potential of Napudet for augmenting the fossil record for a relatively ill-documented time interval (13–10 Ma). SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Boisserie, J.-R., C. Kiarie, F. Lihoreau, and I. Nengo. 2017. Middle Miocene Kenyapotamus (Cetartiodactyla, Hippopotamidae) from Napudet, Turkana Basin, Kenya. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1272055.
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Basal hippopotamines from the upper Miocene of Chorora, Ethiopia
2017Co-Authors: Jean-renaud Boisserie, Fabrice Lihoreau, Berhane Asfaw, Raymond L. Bernor, Shigehiro Katoh, Gen Suwa, Yonas BeyeneAbstract:The Hippopotamidae have been a major component of the African wetland fauna for the last 7 million years, following the ‘Hippopotamine Event,’ i.e., the sudden emergence in the fossil record of the subfamily Hippopotaminae, including both extant species. The general dearth of African fossiliferous deposits dated between 9.5 Ma and 7.5 Ma concealed until now the evolution that led to the Hippopotamine Event and the subsequent success of these large semiaquatic herbivores. Part of this evolution is unveiled by the hippopotamid dental remains found at Chorora, a late Miocene site of the southern Afar Depression in Ethiopia spanning most of the fossil-depleted time interval. Although fragmentary, these remains represent a new, mid-sized hippopotamid species dated to ca. 8 Ma, as well as a somewhat younger, larger form. A cladistic analysis of a large array of cetartiodactyls indicates that the Chorora taxa were basal to the latest Miocene hippopotamines. The new species displays a mosaic of dental characters that support the attribution of the new species to a new genus within Hippopotaminae. The new fossils also clarify the course of early hippopotamine dental evolution. The Chorora hippopotamids suggest that transition to a marked abundance of hippopotamines with their unique dental pattern in African ecosystems occurred within a relatively short time interval, most probably between 8 Ma and 7.5 Ma. http://zoobank.org/urn:lsid:zoobank.org:pub:47B9381F-E3B5-40C9-B9AB-51CC3D0D3A8A SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Boisserie, J.-R., G. Suwa, B. Asfaw, F. Lihoreau, R. L. Bernor, S. Katoh, and Y. Beyene. 2017. Basal hippopotamines from the upper Miocene of Chorora, Ethiopia. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1297718.
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Hippos stem from the longest sequence of terrestrial cetartiodactyl evolution in Africa.
Nature Communications, 2015Co-Authors: Fabrice Lihoreau, Jean-renaud Boisserie, Fredrick Manthi, Stephane DucrocqAbstract:The evolutionary origin of Hippopotamidae, the family of hippos, is poorly understood. Here, the authors describe a new fossil from Kenya that unambiguously roots Hippopotamidae into the group that includes the first large terrestrial mammals to invade Africa, more than 30 million years ago.
Stephane Ducrocq - One of the best experts on this subject based on the ideXlab platform.
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endocasts and brain evolution in anthracotheriidae artiodactyla hippopotamoidea
Journal of Anatomy, 2015Co-Authors: Ghislain Thiery, Stephane DucrocqAbstract:: Anthracotheres are a fossil family of 'Suiformes' from the Old World, North and Central America. They are known from the middle Eocene to the late Pliocene, and are suggested to be the stem group of Hippopotamidae. Yet, their soft anatomy remains poorly known. In this study we describe the virtual endocast of the late Oligocene anthracothere Microbunodon minimum, reconstructed using microtomography, as well as the natural endocast of Merycopotamus medioximus from the late Miocene. These are the first anthracothere endocasts ever described. Particular attention is given to the relative proportions of the brain, the neocortex, the cerebellum and the olfactory bulbs. The 'backward shift' of the pituitary of M. minimum, and the possible presence of a K lobe in M. medioximus, is discussed. Previous statements that some endocranial characters were subject to convergence among mammals are also corroborated.
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Hippos stem from the longest sequence of terrestrial cetartiodactyl evolution in Africa.
Nature Communications, 2015Co-Authors: Fabrice Lihoreau, Jean-renaud Boisserie, Fredrick Manthi, Stephane DucrocqAbstract:The evolutionary origin of Hippopotamidae, the family of hippos, is poorly understood. Here, the authors describe a new fossil from Kenya that unambiguously roots Hippopotamidae into the group that includes the first large terrestrial mammals to invade Africa, more than 30 million years ago.
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Hippos stem from the longest sequence of terrestrial cetartiodactyl evolution in Africa
Nature Communications, 2015Co-Authors: Fabrice Lihoreau, Jean-renaud Boisserie, Fredrick Manthi, Stephane DucrocqAbstract:According to molecular data, hippopotamuses and cetaceans form a clade excluding other extant cetartiodactyls. Despite a wealth of spectacular specimens documenting cetacean evolution, this relationship remains poorly substantiated by the fossil record. Indeed, the evolutionary path leading from the hippo-cetacean ancestor to Hippopotamidae is plagued by missing fossil data and phylogenetic uncertainties. Only an origination within the extinct anthracotheres is compatible with molecular results, substantial filling of phyletic gaps and recent discoveries of early Miocene hippopotamids. Yet, the anthracothere stock that gave rise to Hippopotamidae has not been identified. Consequently, recent phylogenetic accounts do not properly integrate the anthracotheriid hypothesis, and relate Hippopotamidae to a stretched ghost lineage and/or close to Suina. Here we describe a new anthracothere from Lokone (Kenya) that unambiguously roots the Hippopotamidae into a well-identified group of bothriodontines, the first large mammals to invade Africa. The hippos are deeply anchored into the African Paleogene.
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Morphology and phylogenetic relationships of the earliest known hippopotamids (Cetartiodactyla, Hippopotamidae, Kenyapotaminae)
Zoological Journal of the Linnean Society, 2010Co-Authors: Jean-renaud Boisserie, Maeva J Orliac, Rebecca E Fisher, Fabrice Lihoreau, Eleanor M. Weston, Stephane DucrocqAbstract:The earliest known hippopotamids, attributed to the subfamily Kenyapotaminae, are known essentially from dental remains of two species. The first was found in the middle Miocene of Kenya, the second at the beginning of the upper Miocene in eastern and northern Africa. The exact affinities of the Kenyapotaminae are critical for resolving the long debated origin of the Hippopotamidae, as part of the wider question of cetacean affinities within artiodactyls. We performed the first detailed comparative description, character by character, of kenyapotamines, using the following putatively related taxa: Hippopotaminae, Suoidea, and Anthracotheriidae. The development of an improved nomenclature for the dentition facilitates comparisons amongst a wide array of cetartiodactyls. This has permitted the first assessment of the phylogenetic position of Kenyapotaminae using a cladistic analysis. This work provides an emendation of kenyapotamine taxonomy and diversity. Kenyapotaminae are indeed closely related to Hippopotaminae and should be kept within Hippopotamidae, the late Miocene kenyapotamines not necessarily being the forerunners of the first known hippopotamines. Hippopotamidae are deeply nested within anthracotheriids, with crown bothiodontines as sister group, and any close affinities with Suoidea should be rejected. This reinforces a scenario linking cetaceans to Hippopotamoidea (Hippopotamidae + Anthracotheriidae), possibly via other early Palaeogene artiodactyls. RESUME Morphologie et phylogenie des premiers hippopotamides (Cetartiodactyla, Hippopotamidae, Kenyapotaminae).–Les plus anciens hippopotamides, attibues a la sous-famille Kenyapotaminae, sont connus essentiellement par les restes dentaires de deux especes, connues dans le Miocene moyen du Kenya et a la base du Miocene superieur d’Afrique orientale et septantrionale. Les affinites exactes des Kenyapotaminae doivent etre connues pour resoudre le long debat sur l’origine des Hippopotamidae, partie integrante de la question plus large des relations entre cetaces et artiodactyles. Nous avons effectues la premiere comparaison detaillee, caractere par caractere, des kenyapotamines avec les Hippopotaminae, Suoidea, et Anthracotheriidae, grâce au developpement d’une nomenclature dentaire amendee. Sur cette base, nous avons conduit une analyse cladistique de la position phylogenetique des Kenyapotaminae. Nous proposons une emendation de leur taxonomie et de leur diversite. Ils apparaissent proches des Hippopotaminae, et devraient etre conserves au sein des Hippopotamidae, mais les kenyapotamines du Miocene recent ne sont pas necessairement les precurseurs des premiers hippopotamines. Les Hippopotamidae apparaissent profondement enracines auseines Anthracotheriidae, leur group frere incluant les bothriodontines terminaux. Une relation etroite avec les Suoidea est rejetee. Ces resultas renforcent le scenario liant Cetacea et Hippopotamoidea (Hippopotamidae + Anthracotheriidae), et possiblement d’autres artiodactyles du Paleogene ancient. © 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158, 325–366.
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What is a Suiforme (Artiodactyla)?: Contribution of Cranioskeletal and Mitochondrial DNA Data
Molecular Phylogenetics and Evolution, 1998Co-Authors: Claudine Montgelard, Stephane Ducrocq, Emmanuel J P DouzeryAbstract:Abstract Suiformes (Artiodactyla) traditionally includes three families: Suidae, Tayassuidae, and Hippopotamidae but the monophyly of this suborder has recently been questioned from molecular data. A maximum parsimony analysis of molecular, morphological, and combined data was performed on the same set of taxa including representatives of the three Artiodactyla suborders (Suiformes, Ruminantia, and Tylopoda) and Perissodactyla as outgroup. Mitochondrial (cytochromeband 12S rRNA) sequence comparisons support the monophyly of Suina (Suidae and Tayassuidae) and Ancodonta (Hippopotamidae) but not the monophyly of Suiformes. Inversely, our preliminary morphological analysis supports the monophyly of Suiformes whereas relationships among the three families are not resolved. The combined data set does not resolve the relationships between Suina, Ancodonta, and Ruminantia. These results are discussed in relation to morphological characters and paleontological data. Some improvements are suggested to clarify the morphological definition of Suiformes and relationships among them.
Jonathan H. Geisler - One of the best experts on this subject based on the ideXlab platform.
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Hippopotamus and whale phylogeny
Nature, 2009Co-Authors: Jonathan H. Geisler, Jessica M. TheodorAbstract:Arising from: J. G. M. Thewissen, L. N. Cooper, M. T. Clementz, S. Bajpai & B. N. Tiwari Nature 450 , 1190–1194 (2007)10.1038/nature06343 ; Thewissen et al. reply Thewissen et al. ^ 1 describe new fossils from India that apparently support a phylogeny that places Cetacea (that is, whales, dolphins, porpoises) as the sister group to the extinct family Raoellidae, and Hippopotamidae as more closely related to pigs and peccaries (that is, Suina) than to cetaceans. However, our reanalysis of a modified version of the data set they used^ 2 differs in retaining molecular characters and demonstrates that Hippopotamidae is the closest extant family to Cetacea and that raoellids are the closest extinct group, consistent with previous phylogenetic studies^ 2 , 3 . This topology supports the view that the aquatic adaptations in hippopotamids and cetaceans are inherited from their common ancestor^ 4 .
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Hippopotamus and whale phylogeny
Nature, 2009Co-Authors: Jonathan H. Geisler, Jessica M. TheodorAbstract:Arising from: J. G. M. Thewissen, L. N. Cooper, M. T. Clementz, S. Bajpai & B. N. Tiwari , 1190–1194 (2007)10.1038/nature06343 ; Thewissen et al. reply Thewissen et al.1 describe new fossils from India that apparently support a phylogeny that places Cetacea (that is, whales, dolphins, porpoises) as the sister group to the extinct family Raoellidae, and Hippopotamidae as more closely related to pigs and peccaries (that is, Suina) than to cetaceans. However, our reanalysis of a modified version of the data set they used2 differs in retaining molecular characters and demonstrates that Hippopotamidae is the closest extant family to Cetacea and that raoellids are the closest extinct group, consistent with previous phylogenetic studies2,3. This topology supports the view that the aquatic adaptations in hippopotamids and cetaceans are inherited from their common ancestor4.
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Phylogenetic Relationships of Extinct Cetartiodactyls: Results of Simultaneous Analyses of Molecular, Morphological, and Stratigraphic Data
Journal of Mammalian Evolution, 2005Co-Authors: Jonathan H. Geisler, Mark D. UhenAbstract:Although some recent morphological and molecular studies agree that Cetacea is closely related to Hippopotamidae, there is little consensus on the phylogeny within Cetartiodactyla. We addressed this problem by conducting two analyses: (1) a simultaneous cladistic analysis of intrinsic data (morphology and molecules) and (2) a stratocladistic analysis, which included morphological, molecular, and stratigraphic data. Unlike previous simultaneous analyses, we had the opportunity to include data from the recently described hindlimbs of protocetid and pakicetid cetaceans. Our intrinsic dataset includes 73 taxa scored for 8,229 informative characters, of which 208 are morphological and 8,021 molecular. Both analyses supported the exclusion of Mesonychia from Cetartiodactyla and a close phylogenetic relationship between Hippopotamidae and Cetacea. Many polytomies in the strict consensus of the most parsimonious trees for the intrinsic dataset can be attributed to differing positions for Raoellidae, which in some trees is the sister-group to Cetacea. Pruning Raoellidae and 18 other taxa from all most parsimonious produced a fully resolved agreement subtree, which indicates that the Old World taxa Cebochoeru s and Mixtotherium are successive stem taxa to Whippomorpha (i.e., Cetacea + Hippopotamidae). The main result of adding stratigraphic information to the intrinsic dataset was that we found fewer most parsimonious trees, which in most respects were congruent with a subset of the shortest trees for the intrinsic dataset. Our stratocladistic analysis supports species of Diacodexis as the most basal cetartiodactyls, a clade of suiform cetartiodactyls, a monophyletic Tylopoda that includes Protoceratidae, and a monophyletic Carnivora. We were unable to identify any pre-Miocene stem taxa to Hippopotamidae, thus its ghost lineage is still 39 million years long. The relatively low Bremer support for many nodes in our trees indicates that our phylogenetic hypotheses should be subjected to further testing.
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MORPHOLOGICAL SUPPORT FOR A CLOSE RELATIONSHIP BETWEEN HIPPOS AND WHALES
Journal of Vertebrate Paleontology, 2003Co-Authors: Jonathan H. Geisler, Mark D. UhenAbstract:Recent discoveries of the ankles of fossil whales, reported by Gingerich et al. (2001) and Thewissen et al. (2001b), corroborated the molecular hypothesis that Cetacea (whales, dolphins, and porpoises) are closely related to artiodactyls (evenhoofed mammals including hippopotami, pigs, deer, and camels); however, major points of disagreement remain. A morphology-based study incorporating some of these new data (Thewissen et al., 2001b) supported the exclusion of Cetacea from the clade of living artiodactyls. In contrast, a vast amount of molecular data support placement of Cetacea within Artiodactyla, as close relatives to Hippopotamidae (Gatesy et al., 1996, 1999; Montgelard et al., 1997; Shimamura et al., 1997, 1999; Nikaido et al., 2001). Here we report that morphological data from extinct and extant taxa support placement of Cetacea within Artiodactyla as the closest relatives of Hippopotamidae (Fig. 1B) and indicate that molecular and morphological evidence for the phylogeny of these taxa are now much more congruent than previously thought.
Alexander S. Graphodatsky - One of the best experts on this subject based on the ideXlab platform.
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Cross-species chromosome painting in Cetartiodactyla: Reconstructing the karyotype evolution in key phylogenetic lineages
Chromosome Research, 2009Co-Authors: Anastasia I. Kulemzina, Vladimir A. Trifonov, Polina L. Perelman, Nadezhda V. Rubtsova, Vitaly Volobuev, Malcolm A. Ferguson-smith, Roscoe Stanyon, Fengtang Yang, Alexander S. GraphodatskyAbstract:Recent molecular and morphological studies place Artiodactyla and Cetacea into the order Cetartiodactyla. Within the Cetartiodactyla such families as Bovidae, Cervidae, and Suidae are well studied by comparative chromosome painting, but many taxa that are crucial for understanding cetartiodactyl phylogeny remain poorly studied. Here we present the genome-wide comparative maps of five cetartiodactyl species obtained by chromosome painting with human and dromedary paint probes from four taxa: Cetacea, Hippopotamidae, Giraffidae, and Moschidae. This is the first molecular cytogenetic report on pilot whale, hippopotamus, okapi, and Siberian musk deer. Our results, when integrated with previously published comparative chromosome maps allow us to reconstruct the evolutionary pathway and rates of chromosomal rearrangements in Cetartiodactyla. We hypothesize that the putative cetartiodactyl ancestral karyotype (CAK) contained 25–26 pairs of autosomes, 2n = 52–54, and that the association of human chromosomes 8/9 could be a cytogenetic signature that unites non-camelid cetartiodactyls. There are no unambiguous cytogenetic landmarks that unite Hippopotamidae and Cetacea. If we superimpose chromosome rearrangements on the supertree generated by Price and colleagues, several homoplasy events are needed to explain cetartiodactyl karyotype evolution. Our results apparently favour a model of non-random breakpoints in chromosome evolution. Cetariodactyl karyotype evolution is characterized by alternating periods of low and fast rates in various lineages. The highest rates are found in Suina (Suidae+Tayasuidae) lineage (1.76 rearrangements per million years (R/My)) and the lowest in Cetaceans (0.07 R/My). Our study demonstrates that the combined use of human and camel paints is highly informative for revealing evolutionary karyotypic rearrangements among cetartiodactyl species.