Gondwanan Origin of Major Monocot Groups Inferred from Dispersal-Vicariance Analysis

Historical biogeography of major monocot groups was investigated by biogeographical analysis of a dated phylogeny including 79 of the 81 monocot families using the Angiosperm Phylogeny Group II (APG II) classification. Five major areas were used to describe the family distributions: Eurasia, North America, South America, Africa including Madagascar, and Australasia including New Guinea, New Caledonia, and New Zealand. In order to investigate the possible correspondence with continental breakup, the tree with its terminal distributions was fitted to the geological area cladogram ((Eurasia, North America), (Africa, (South America, Australasia)) and to alternative area cladograms using the TreeFitter program. The results indicated that monocot evolution is related to the comparatively late (Eocene) connection (via Antarctica) and break up of South America and Australasia, but not to the much older connections and separations of the other areas. The family phylogeny and distributions were also subjected to dispersal-vicariance analysis using the DIVA program. A prevalence of Australasia and South America among the DIVA optimizations inside core monocots (i.e., monocots excluding Acorus and Alismatales), and especially so in Liliales, Asparagales, and at deep nodes in the core monocot and commelinid phylogeny, points to a South Gondwanan origin for those major groups; South Gondwana comprises South America (at least southern South America), Antarctica, and Australasia. Africa and the Northern Hemisphere were presumably not parts of the ancestral area for core monocots and commelinids

An extinct Eocene taxon of the daisy family (Asteraceae): Evolutionary, ecological and biogeographical implications

Background and Aims: Morphological, molecular and biogeographical information bearing on early evolution of the sunflower alliance of families suggests that the clade containing the extant daisy family (Asteraceae) differentiated in South America during the Eocene, although palaeontological studies on this continent failed to reveal conclusive support for this hypothesis. Here we describe in detail Raiguenrayun cura gen. & sp. nov., an exceptionally well preserved capitulescence of Asteraceae recovered from Eocene deposits of northwestern Patagonia, Argentina. Methods: The fossil was collected from the 47·5 million-year-old Huitrera Formation at the Estancia Don Hiplito locality, Ro Negro Province, Argentina. Key Results: The arrangement of the capitula in a cymose capitulescence, the many-flowered capitula with multiseriateimbricate involucral bracts and the pappus-like structures indicate a close morphological relationship with Asteraceae. Raiguenrayun cura and the associated pollen Mutisiapollis telleriae do not match exactly any living member of the family, and clearly represent extinct taxa. They share a mosaic of morphological features today recognized in taxa phylogenetically close to the root of Asteraceae, such as Stifftieae, Wunderlichioideae and Gochnatieae (Mutisioideae sensu lato) and Dicomeae and Oldenburgieae (Carduoideae), today endemic to or mainly distributed in South America and Africa, respectively. Conclusions: This is the first fossil genus of Asteraceae based on an outstandingly preserved capitulescence that might represent the ancestor of MutisioideaeCarduoideae. It might have evolved in southern South America some time during the early Palaeogene and subsequently entered Africa, before the biogeographical isolation of these continents became much more pronounced. The new fossil represents the first reliable point for calibration, favouring an earlier date to the split between Barnadesioideae and the rest of Asteraceae than previously thought, which can be traced back at least 47·5 million years. This is the oldest well dated member of Asteraceae and perhaps the earliest indirect evidence for bird pollination in the family.Facultad de Ciencias Naturales y Muse

An extinct Eocene taxon of the daisy family (Asteraceae): Evolutionary, ecological and biogeographical implications

Background and Aims: Morphological, molecular and biogeographical information bearing on early evolution of the sunflower alliance of families suggests that the clade containing the extant daisy family (Asteraceae) differentiated in South America during the Eocene, although palaeontological studies on this continent failed to reveal conclusive support for this hypothesis. Here we describe in detail Raiguenrayun cura gen. & sp. nov., an exceptionally well preserved capitulescence of Asteraceae recovered from Eocene deposits of northwestern Patagonia, Argentina. Methods: The fossil was collected from the 47·5 million-year-old Huitrera Formation at the Estancia Don Hiplito locality, Ro Negro Province, Argentina. Key Results: The arrangement of the capitula in a cymose capitulescence, the many-flowered capitula with multiseriateimbricate involucral bracts and the pappus-like structures indicate a close morphological relationship with Asteraceae. Raiguenrayun cura and the associated pollen Mutisiapollis telleriae do not match exactly any living member of the family, and clearly represent extinct taxa. They share a mosaic of morphological features today recognized in taxa phylogenetically close to the root of Asteraceae, such as Stifftieae, Wunderlichioideae and Gochnatieae (Mutisioideae sensu lato) and Dicomeae and Oldenburgieae (Carduoideae), today endemic to or mainly distributed in South America and Africa, respectively. Conclusions: This is the first fossil genus of Asteraceae based on an outstandingly preserved capitulescence that might represent the ancestor of MutisioideaeCarduoideae. It might have evolved in southern South America some time during the early Palaeogene and subsequently entered Africa, before the biogeographical isolation of these continents became much more pronounced. The new fossil represents the first reliable point for calibration, favouring an earlier date to the split between Barnadesioideae and the rest of Asteraceae than previously thought, which can be traced back at least 47·5 million years. This is the oldest well dated member of Asteraceae and perhaps the earliest indirect evidence for bird pollination in the family.Facultad de Ciencias Naturales y Muse

An extinct Eocene taxon of the daisy family (Asteraceae): Evolutionary, ecological and biogeographical implications

Background and Aims: Morphological, molecular and biogeographical information bearing on early evolution of the sunflower alliance of families suggests that the clade containing the extant daisy family (Asteraceae) differentiated in South America during the Eocene, although palaeontological studies on this continent failed to reveal conclusive support for this hypothesis. Here we describe in detail Raiguenrayun cura gen. & sp. nov., an exceptionally well preserved capitulescence of Asteraceae recovered from Eocene deposits of northwestern Patagonia, Argentina. Methods: The fossil was collected from the 47·5 million-year-old Huitrera Formation at the Estancia Don Hiplito locality, Ro Negro Province, Argentina. Key Results: The arrangement of the capitula in a cymose capitulescence, the many-flowered capitula with multiseriateimbricate involucral bracts and the pappus-like structures indicate a close morphological relationship with Asteraceae. Raiguenrayun cura and the associated pollen Mutisiapollis telleriae do not match exactly any living member of the family, and clearly represent extinct taxa. They share a mosaic of morphological features today recognized in taxa phylogenetically close to the root of Asteraceae, such as Stifftieae, Wunderlichioideae and Gochnatieae (Mutisioideae sensu lato) and Dicomeae and Oldenburgieae (Carduoideae), today endemic to or mainly distributed in South America and Africa, respectively. Conclusions: This is the first fossil genus of Asteraceae based on an outstandingly preserved capitulescence that might represent the ancestor of MutisioideaeCarduoideae. It might have evolved in southern South America some time during the early Palaeogene and subsequently entered Africa, before the biogeographical isolation of these continents became much more pronounced. The new fossil represents the first reliable point for calibration, favouring an earlier date to the split between Barnadesioideae and the rest of Asteraceae than previously thought, which can be traced back at least 47·5 million years. This is the oldest well dated member of Asteraceae and perhaps the earliest indirect evidence for bird pollination in the family.Facultad de Ciencias Naturales y Muse

Rektorsbloggen

Kåre Bremer startade sin blogg när han hade varit rektor vid Stockholms universitet i knappt ett och ett halvt år. Det blev ett par inlägg per vecka fram till hans avgång som rektor i januari 2013. Sammanlagt blev det 930 blogginlägg. Intentionen var att använda den för intern kommunikation. Snart visade det sig att bloggen lästes regelbundet av företrädare för andra lärosäten, myndigheter och media. Kåre Bremers blogg blev en effektiv informationskanal för Stockholms universitet både internt och externt – med många följare och stort genomslag. Rektorsbloggen är ett tidsdokument med ögonblicksbilder från Stockholms universitets och hela högskolesveriges historia under Kåre Bremers rektorstid.Kåre Bremer affiliering Stockholms universitet, Högskoleföreningen.</p

The pregnancy-specific glycoprotein family of the immunoglobulin superfamily: Identification of new members and estimation of family size

The members of the carcinoembryonic antigen (CEA)/pregnancy-specific glycoprotein (PSG) gene family have a characteristic N-terminal domain that is homologous to the immunoglobulin variable region. We have estimated the size of the PSG subfamily by identification of N-domain exons from isolated genomic clones and from total genomic DNA through PCR amplification and DNA sequence determination. The PSG subfamily contains at least 11 different genes. For 7 of these, two DNA sequences differing from each other in 1 to 4 nucleotides were detected. Most likely, they represent different alleles. They are PSG1, PSG2, PSG3, PSG4, PSG5, PSG6, PSG7, PSG8, PSG11, PSG12, and PSG13. Six of the N-domain sequences described here are new. All of the PSGs except PSG1, PSG4, and PSG8 contained the arginine-glycine-aspartic acid sequence at position 93–95 corresponding to the complementarity determining region 3 of immunoglobulin. Parsimony analysis of 24 CEA and PSG sequences using 12 members of the immunoglobulin gene superfamily as out-groups to root the family free shows that the N-domain of the CEA group genes evolved in one major branch and the PSG group genes in the other