Topic
Daphnandra
About: Daphnandra is a research topic. Over the lifetime, 30 publications have been published within this topic receiving 302 citations.
Papers
TL;DR: Calibration of rbcL substitution rates with the fossils suggests an initial diversification of the Atherospermataceae family at 100-140 million years ago (MYA), probably in West Gondwana, early entry into Antarctica, and long-distance dispersal to New Zealand and New Caledonia at 50-30 MYA by the ancestors of L. novae-zelandiae and Nemuaron.
Abstract: Previous studies of the small Southern Hemisphere family Atherospermataceae have drawn contradictory conclusions regarding the number of transantarctic disjunctions and role of transoceanic dispersal in its evolution. Clariecation of intergeneric relationships is critical to resolving (1) whether the two Chilean species, Laurelia sempervirens and Laureliopsis philippiana, are related to different Austral-Paciec species, implying two transantarctic disjunctions as suggested by morphology; (2) where the group is likely to have originated; and (3) whether observed disjunctions reeect the breakup of Gondwana. We analyzed chloroplast DNA sequences from six regions (the rbcL gene, the rpl16 intron, and the trnL-trnF, trnT-trnL, psbA-trnH, and atpB-rbcL spacer regions; for all six regions, 4,372 bp) for all genera and most species of Atherospermataceae, using parsimony and maximum likelihood (ML). The family's sister group, the Chilean endemic Gomortega nitida (Gomortegaceae), was used to root the tree. Parsimony and ML yielded identical single best trees that contain three well-supported clades (¸ 75% bootstrap): Daphnandra and Doryphora from south-eastern Australia; Atherosperma and Nemuaron from Australia-Tasmania and New Caledonia, respectively; and Laurelia novae-zelandiae and Laureliopsis philippiana from New Zealand and Chile, respectively. The second Chilean species, Laurelia sempervirens, is sister to this last clade. Likelihood ratio testing did not reject the molecular clock assumption for the rbcL data, which can therefore be used for divergence time estimates. The atherosperm fossil record, which goes back to the Upper Cretaceous, includes pollen, wood, and leaf fossils from Europe, Africa, South America, Antarctica, New Zealand, and Tasmania. Calibration of rbcL substitution rates with the fossils suggests an initial diversiecation of the family at 100-140 million years ago (MYA), probably in West Gondwana, early entry into Antarctica, and long-distance dispersal to New Zealand and New Caledonia at 50-30 MYA by the ancestors of L. novae-zelandiae and Nemuaron. (Biogeography; Gondwana; likelihood ratio test; maximum likelihood; molecular clock; phylogeny; rbcL substitution rates.)
110 citations
TL;DR: Two previously unrecognised morphotypes, which can be assigned to the Monimiaceae sensu lato, are described, and represents the first record of this family in the wood flora of Antarctica.
Abstract: Palaeofloristic studies of the Antarctic Peninsula region are important in furthering our understanding of (i) the radiation and rise to ecological dominance of the angiosperms in the Southern Hemisphere during the Late Cretaceous and (ii) the present day disjunct austral vegetation. Investigations of Upper Cretaceous and Early Tertiary sediments of this region yield a rich assemblage of well-preserved fossil dicotyledonous angiosperm wood which provides evidence for the existence, since the Late Cretaceous, of temperate forests similar in composition to those found in present-day southern South America, New Zealand and Australia. This paper describes two previously unrecognised morphotypes, which can be assigned to the Monimiaceae sensu lato, and represents the first record of this family in the wood flora of Antarctica. Specimens belonging to the first fossil morphotype have been assigned to Hedycaryoxylon SUss (subfamily Monimioideae) because they exhibit anatomical features characteristic of Hedycaryoxylon and extant Hedycarya J.R.Forst. & G.Forst. and Tambourissa Sonn. Characters include diffuse porosity, vessels which are mainly solitary with scalariform perforation plates, opposite to scalariform intervascular pitting, paratracheal parenchyma, septate fibres and tall (>3 mm), wide multiseriate rays with a length: breadth ratio of approximately 1: 4. Specimens belonging to the second morphotype have been assigned to Atherospermoxylon KrAusel, erected for fossil woods of the Monimiaceae in the tribe Atherospermeae (now Atherospermataceae) in that they exhibit anatomical features similar to Atherospermoxylon and extant Daphnandra Benth., Doryphora Endl. and Laurelia novae-zelandiae A.Cunn. These characters include diffuse to semi-ring porosity, scalariform perforation plates with up to 25 bars, septate fibres, relatively short (<1 mm) rays with a length: breadth ratio of between 1: 4 and 1: 11.
57 citations
TL;DR: Traces of white line centered lamellae, characteristic of some members of the subfamily Monimioideae of the Monimiaceae, were found within the foot and columellar stratum of Atherosperma.
Abstract: Atherosperma moschatum Labill., Daphnandra micrantha (Tul.) Benth. and Doryphora sassafras Endl., of the family Atherospermataceae (syn. subfamily Atherospermoideae of the Monimiaceae) of the Laurales, have medium‐sized, isopolar, globose to globose‐ellipsoidal pollen grains. The pollen is either dicolpate, with two elongated apertures centered at the poles (Doryphora) or meridionosulcate, with a median encircling aperture which narrows markedly (Atherosperma) or less markedly (Daphnandra) in equatorial regions. Exine is tectate‐columellate with an uneven foot layer of partly‐fused, large, irregular sized, granules. Traces of white line centered lamellae, characteristic of some members of the subfamily Monimioideae of the Monimiaceae, were found within the foot and columellar stratum of Atherosperma. An endexine is probably absent. In apertural regions exine processes are reduced in size and form clusters which are separated by smooth regions where exine seems to be almost completely lacking. In ...
26 citations
TL;DR: In this article, the trilobine-type structure of Micranthine has been shown to have the triliobine type structure (VI) and the new alkaloids O-methylmicranthines (IV), its diastereoisomer telobine (VI), and ON-dimethylmicranthsine (III) have been isolated from an unnamed species from northern New South Wales, together with the known alkaloid nortenuipine and fangchinoline.
Abstract: Micranthine has been shown to have the trilobine-type structure (VII). The new alkaloids O-methylmicranthine (IV), its diastereoisomer telobine (VI), and ON-dimethylmicranthine (III) have been isolated from an unnamed species from northern New South Wales, together with the known alkaloids nortenuipine and fangchinoline.
10 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2016 | 1 |
| 2010 | 1 |
| 2001 | 2 |
| 2000 | 1 |
| 1993 | 2 |
| 1992 | 1 |