Signatures of seaway closures and founder dispersal in the phylogeny of a circumglobally distributed seahorse lineage
- Teske, Peter R, Hamilton, Healy, Matthee, Conrad A, Barker, Nigel P
- Authors: Teske, Peter R , Hamilton, Healy , Matthee, Conrad A , Barker, Nigel P
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6549 , http://hdl.handle.net/10962/d1006005
- Description: The importance of vicariance events on the establishment of phylogeographic patterns in the marine environment is well documented, and generally accepted as an important cause of cladogenesis. Founder dispersal (i.e. long-distance dispersal followed by founder effect speciation) is also frequently invoked as a cause of genetic divergence among lineages, but its role has long been challenged by vicariance biogeographers. Founder dispersal is likely to be common in species that colonize remote habitats by means of rafting (e.g. seahorses), as long-distance dispersal events are likely to be rare and subsequent additional recruitment from the source habitat is unlikely. In the present study, the relative importance of vicariance and founder dispersal as causes of cladogenesis in a circumglobally distributed seahorse lineage was investigated using molecular dating. A phylogeny was reconstructed using sequence data from mitochondrial and nuclear markers, and the well-documented closure of the Central American seaway was used as a primary calibration point to test whether other bifurcations in the phylogeny could also have been the result of vicariance events. The feasibility of three other vicariance events was explored: a) the closure of the Indonesian Seaway, resulting in sister lineages associated with the Indian Ocean and West Pacific, respectively; b) the closure of the Tethyan Seaway, resulting in sister lineages associated with the Indo-Pacific and Atlantic Ocean, respectively, and c) continental break-up during the Mesozoic followed by spreading of the Atlantic Ocean, resulting in pairs of lineages with amphi-Atlantic distribution patterns.
- Full Text:
- Date Issued: 2007
- Authors: Teske, Peter R , Hamilton, Healy , Matthee, Conrad A , Barker, Nigel P
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6549 , http://hdl.handle.net/10962/d1006005
- Description: The importance of vicariance events on the establishment of phylogeographic patterns in the marine environment is well documented, and generally accepted as an important cause of cladogenesis. Founder dispersal (i.e. long-distance dispersal followed by founder effect speciation) is also frequently invoked as a cause of genetic divergence among lineages, but its role has long been challenged by vicariance biogeographers. Founder dispersal is likely to be common in species that colonize remote habitats by means of rafting (e.g. seahorses), as long-distance dispersal events are likely to be rare and subsequent additional recruitment from the source habitat is unlikely. In the present study, the relative importance of vicariance and founder dispersal as causes of cladogenesis in a circumglobally distributed seahorse lineage was investigated using molecular dating. A phylogeny was reconstructed using sequence data from mitochondrial and nuclear markers, and the well-documented closure of the Central American seaway was used as a primary calibration point to test whether other bifurcations in the phylogeny could also have been the result of vicariance events. The feasibility of three other vicariance events was explored: a) the closure of the Indonesian Seaway, resulting in sister lineages associated with the Indian Ocean and West Pacific, respectively; b) the closure of the Tethyan Seaway, resulting in sister lineages associated with the Indo-Pacific and Atlantic Ocean, respectively, and c) continental break-up during the Mesozoic followed by spreading of the Atlantic Ocean, resulting in pairs of lineages with amphi-Atlantic distribution patterns.
- Full Text:
- Date Issued: 2007
The identity of Albuca caudata Jacq. (Hyacinthaceae) and a description of a new related species : A. bakeri
- Martinez-Azorin, Mario, Cresbo, Manuel B, Dold, Anthony P, Barker, Nigel P
- Authors: Martinez-Azorin, Mario , Cresbo, Manuel B , Dold, Anthony P , Barker, Nigel P
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6528 , http://hdl.handle.net/10962/d1005969
- Description: The name Albuca caudata Jacq. has been widely misunderstood or even ignored since its description in 1791. After studying herbarium specimens and living populations in South Africa, plants fitting Jacquin´s concept of that species are found to be widely distributed in the Eastern Cape, mainly in the Albany centre of Endemism. Furthermore, some divergent specimens matching Baker´s concept of Albuca caudata are described as a new related species: Albuca bakeri. Data on typification, morphology, ecology, and distribution are reported for both taxa. Affinities and divergences with other close allies are also discussed.
- Full Text:
- Date Issued: 2011
- Authors: Martinez-Azorin, Mario , Cresbo, Manuel B , Dold, Anthony P , Barker, Nigel P
- Date: 2011
- Language: English
- Type: Article
- Identifier: vital:6528 , http://hdl.handle.net/10962/d1005969
- Description: The name Albuca caudata Jacq. has been widely misunderstood or even ignored since its description in 1791. After studying herbarium specimens and living populations in South Africa, plants fitting Jacquin´s concept of that species are found to be widely distributed in the Eastern Cape, mainly in the Albany centre of Endemism. Furthermore, some divergent specimens matching Baker´s concept of Albuca caudata are described as a new related species: Albuca bakeri. Data on typification, morphology, ecology, and distribution are reported for both taxa. Affinities and divergences with other close allies are also discussed.
- Full Text:
- Date Issued: 2011
The snake family Psammophiidae (Reptilia: Serpentes): phylogenetics and species delimitation in the African sand snakes (Psammophis Boie, 1825) and allied genera
- Kelly, Christopher M R, Barker, Nigel P, Villet, Martin H, Broadley, Donald G, Branch, William R
- Authors: Kelly, Christopher M R , Barker, Nigel P , Villet, Martin H , Broadley, Donald G , Branch, William R
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6522 , http://hdl.handle.net/10962/d1005953
- Description: This study constitutes the first evolutionary investigation of the snake family Psammophiidae—the most widespread, most clearly defined, yet perhaps the taxonomically most problematic of Africa's familylevel snake lineages. Little is known of psammophiid evolutionary relationships, and the type genus Psammophis is one of the largest and taxonomically most complex of the African snake genera. Our aims were to reconstruct psammophiid phylogenetic relationships and to improve characterisation of species boundaries in problematic Psammophis species complexes. We used approximately 2500 bases of DNA sequence from the mitochondrial and nuclear genomes, and 114 terminals covering all psammophiid genera and incorporating approximately 75% of recognised species and subspecies. Phylogenetic reconstructions were conducted primarily in a Bayesian framework and we used the Wiens/Penkrot protocol to aid species delimitation. Rhamphiophis is diphyletic, with Rhamphiophis acutus emerging sister to Psammophylax. Consequently we transfer the three subspecies of Rhamphiophis acutus to the genus Psammophylax. The monotypic genus Dipsina is sister to Psammophis. The two species of Dromophis occupy divergent positions deeply nested within Psammophis, and we therefore relegate Dromophis to the synonymy of Psammophis. Our results allow division of the taxonomically problematic Psammophis 'sibilans' species complex into two monophyletic entities, provisionally named the 'phillipsii' and 'subtaeniatus' complexes. Within these two clades we found support for the status of many existing species, but not for a distinction between P.p. phillipsii and P. mossambicus. Additionally, P. cf. phillipsii occidentalis deserves species status as the sister taxon of P. brevirostris.
- Full Text:
- Date Issued: 2008
- Authors: Kelly, Christopher M R , Barker, Nigel P , Villet, Martin H , Broadley, Donald G , Branch, William R
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6522 , http://hdl.handle.net/10962/d1005953
- Description: This study constitutes the first evolutionary investigation of the snake family Psammophiidae—the most widespread, most clearly defined, yet perhaps the taxonomically most problematic of Africa's familylevel snake lineages. Little is known of psammophiid evolutionary relationships, and the type genus Psammophis is one of the largest and taxonomically most complex of the African snake genera. Our aims were to reconstruct psammophiid phylogenetic relationships and to improve characterisation of species boundaries in problematic Psammophis species complexes. We used approximately 2500 bases of DNA sequence from the mitochondrial and nuclear genomes, and 114 terminals covering all psammophiid genera and incorporating approximately 75% of recognised species and subspecies. Phylogenetic reconstructions were conducted primarily in a Bayesian framework and we used the Wiens/Penkrot protocol to aid species delimitation. Rhamphiophis is diphyletic, with Rhamphiophis acutus emerging sister to Psammophylax. Consequently we transfer the three subspecies of Rhamphiophis acutus to the genus Psammophylax. The monotypic genus Dipsina is sister to Psammophis. The two species of Dromophis occupy divergent positions deeply nested within Psammophis, and we therefore relegate Dromophis to the synonymy of Psammophis. Our results allow division of the taxonomically problematic Psammophis 'sibilans' species complex into two monophyletic entities, provisionally named the 'phillipsii' and 'subtaeniatus' complexes. Within these two clades we found support for the status of many existing species, but not for a distinction between P.p. phillipsii and P. mossambicus. Additionally, P. cf. phillipsii occidentalis deserves species status as the sister taxon of P. brevirostris.
- Full Text:
- Date Issued: 2008
Tri-locus sequence data reject a Gondwanan origin hypothesis for the African/South Pacific crab genus Hymenosoma
- Teske, Peter R, McLay, Colin L, Sandoval-Castillo, Jonathan, Papadopoulos, Isabelle, Newman, Brent K, Griffiths, Charles L, McQuaid, Christopher D, Barker, Nigel P, Borgonie, Gaetan, Beheregaray, Luciano B
- Authors: Teske, Peter R , McLay, Colin L , Sandoval-Castillo, Jonathan , Papadopoulos, Isabelle , Newman, Brent K , Griffiths, Charles L , McQuaid, Christopher D , Barker, Nigel P , Borgonie, Gaetan , Beheregaray, Luciano B
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6547 , http://hdl.handle.net/10962/d1006003
- Description: Crabs of the family Hymenosomatidae are common in coastal and shelf regions throughout much of the southern hemisphere. One of the genera in the family, Hymenosoma, is represented in Africa and the South Pacific (Australia and New Zealand). This distribution can be explained either by vicariance (presence of the genus on the Gondwanan supercontinent and divergence following its break-up) or more recent transoceanic dispersal from one region to the other. We tested these hypotheses by reconstructing phylogenetic relationships among the seven presently-accepted species in the genus, as well as examining their placement among other hymenosomatid crabs, using sequence data from two nuclear markers (Adenine Nucleotide Transporter [ANT] exon 2 and 18S rDNA) and three mitochondrial markers (COI, 12S and 16S rDNA). The five southern African representatives of the genus were recovered as a monophyletic lineage, and another southern African species, Neorhynchoplax bovis, was identified as their sister taxon. The two species of Hymenosoma from the South Pacific neither clustered with their African congeners, nor with each other, and should therefore both be placed into different genera. Molecular dating supports a post-Gondwanan origin of the Hymenosomatidae. While long-distance dispersal cannot be ruled out to explain the presence of the family Hymenosomatidae on the former Gondwanan land-masses and beyond, the evolutionary history of the African species of Hymenosoma indicates that a third means of speciation may be important in this group: gradual along-coast dispersal from tropical towards temperate regions, with range expansions into formerly inhospitable habitat during warm climatic phases, followed by adaptation and speciation during subsequent cooler phases.
- Full Text:
- Date Issued: 2009
- Authors: Teske, Peter R , McLay, Colin L , Sandoval-Castillo, Jonathan , Papadopoulos, Isabelle , Newman, Brent K , Griffiths, Charles L , McQuaid, Christopher D , Barker, Nigel P , Borgonie, Gaetan , Beheregaray, Luciano B
- Date: 2009
- Language: English
- Type: Article
- Identifier: vital:6547 , http://hdl.handle.net/10962/d1006003
- Description: Crabs of the family Hymenosomatidae are common in coastal and shelf regions throughout much of the southern hemisphere. One of the genera in the family, Hymenosoma, is represented in Africa and the South Pacific (Australia and New Zealand). This distribution can be explained either by vicariance (presence of the genus on the Gondwanan supercontinent and divergence following its break-up) or more recent transoceanic dispersal from one region to the other. We tested these hypotheses by reconstructing phylogenetic relationships among the seven presently-accepted species in the genus, as well as examining their placement among other hymenosomatid crabs, using sequence data from two nuclear markers (Adenine Nucleotide Transporter [ANT] exon 2 and 18S rDNA) and three mitochondrial markers (COI, 12S and 16S rDNA). The five southern African representatives of the genus were recovered as a monophyletic lineage, and another southern African species, Neorhynchoplax bovis, was identified as their sister taxon. The two species of Hymenosoma from the South Pacific neither clustered with their African congeners, nor with each other, and should therefore both be placed into different genera. Molecular dating supports a post-Gondwanan origin of the Hymenosomatidae. While long-distance dispersal cannot be ruled out to explain the presence of the family Hymenosomatidae on the former Gondwanan land-masses and beyond, the evolutionary history of the African species of Hymenosoma indicates that a third means of speciation may be important in this group: gradual along-coast dispersal from tropical towards temperate regions, with range expansions into formerly inhospitable habitat during warm climatic phases, followed by adaptation and speciation during subsequent cooler phases.
- Full Text:
- Date Issued: 2009