Recent Synchronous Radiation of a Living Fossil

  title={Recent Synchronous Radiation of a Living Fossil},
  author={Nathalie S. Nagalingum and Charles R. Marshall and Tiago Bosisio Quental and Hardeep Singh Rai and Damon P. Little and Sarah Mathews},
  pages={796 - 799}
Despite their ancient origin, the majority of extant cycad species radiated within the past 10 million years. Modern survivors of previously more diverse lineages are regarded as living fossils, particularly when characterized by morphological stasis. Cycads are often cited as a classic example, reaching their greatest diversity during the Jurassic–Cretaceous (199.6 to 65.5 million years ago) then dwindling to their present diversity of ~300 species as flowering plants rose to dominance. Using… 

Living Fossil Younger than Thought

  • S. Renner
  • Geography, Environmental Science
  • 2011
It is shown that today's cycads evolved from a small number of ancestor species that lived no more than around 12 million years ago.

How Was the Australian Flora Assembled Over the Last 65 Million Years? A Molecular Phylogenetic Perspective

Using molecular phylogenies to test hypotheses derived from the fossil record, this work reviews the principal forces that transformed the ancestral Gondwanan rainforest through the Cenozoic.

Current 'relicts' more dynamic in history than previously thought.

Qi et al. addressed two important questions connected to the evolution of relict genera Cercidiphyllum by using genetic information from both chloroplast and nuclear DNAs, and assessing molecular structure and diversity in relation to past and present geographical distributions.

Genomic signatures of evolution in Nautilus—An endangered living fossil

Investigating three major aspects of the evolutionary history of living fossils: cryptic speciation, population genetics and effective population sizes, using members of the genera Nautilus and Allonautilus as classic examples of true living fossils reveals significant genome‐wide and locus‐specific signatures of selection between species and differentiated populations.

Pleistocene diversification in an ancient lineage: a role for glacial cycles in the evolutionary history of Dioon Lindl. (Zamiaceae).

This study confirms the Pleistsocene age of Dioon species and implicates Pleistocene climate change and established topography in lineage spitting, and adds to the understanding of the cycads as evolutionarily dynamic lineages, not relicts or evolutionary dead ends.

Extant diversity of bryophytes emerged from successive post-Mesozoic diversification bursts.

Overall estimates of net species diversification are approximately half those reported in ferns and ∼30% those described for angiosperms, and statistical rate analyses reveal that mosses and liverworts underwent bursts of diversification since the mid-Mesozoic.

Multiple global radiations in tadpole shrimps challenge the concept of ‘living fossils’

The results suggest at least two bouts of global radiation in Notostraca, one of them recent, so questioning the validity of the ‘living fossils’ concept in groups where cryptic speciation is widespread is questioned.

Global history of the ancient monocot family Araceae inferred with models accounting for past continental positions and previous ranges based on fossils.

The authors' complete genus-level time-scale for the Araceae may prove to be useful for ecological and physiological studies, and past distributions inferred when fossils are included differ in nontrivial ways from those without fossils.

Not that young: combining plastid phylogenomic, plate tectonic and fossil evidence indicates a Palaeogene diversification of Cycadaceae

The findings challenged the previously proposed Middle-Late Miocene diversification of cycads and Indochina origin for Cycadaceae and highlighted the importance of combining phylogenetic clades, tectonic events, and fossils for rebuilding the evolutionary history of lineages that have undergone massive extinctions.

Phylogenomics supports a Cenozoic rediversification of the “living fossil” Isoetes

This study applies multiple dating methods to genome-wide datasets to infer the origin of extant species of Isoetes, a group of mostly aquatic and semi-aquatic isoetalean lycopsids, which closely resemble fossil forms dating back to the Triassic.



Contemporaneous and recent radiations of the world's major succulent plant lineages

Using a hybrid phylogenomic approach, it is estimated that the cactus lineage diverged from its closest relatives ≈35 million years ago (Ma), however, major diversification events in cacti were more recent, with most species-rich clades originating in the late Miocene.

Cenozoic extinctions account for the low diversity of extant gymnosperms compared with angiosperms.

Compared with angiosperms, living gymnosperm groups are not ancient, indicating that gymnosperms suffered major extinctions when climate changed in the Oligocene and Miocene and some probably survived after making adaptive shifts.

Evolutionary explosions and the phylogenetic fuse.

Explosive Radiation or Cryptic Mass Extinction? Interpreting Signatures in Molecular Phylogenies

  • M. CrispL. Cook
  • Biology
    Evolution; international journal of organic evolution
  • 2009
It is argued that an alternative process might explain apparently rapid radiations (“broom-and-handle” or “stemmy” patterns seen in many phytogenies) with no need to invoke dramatic increase in the rate of diversification.

A fossil‐calibrated relaxed clock for Ephedra indicates an Oligocene age for the divergence of Asian and New World clades and Miocene dispersal into South America

Results from a relaxed clock with an uncorrelated rates model and fossil‐based calibration reveal that New World species are monophyletic and diverged from their mostly Asian sister clade some 30 mya, fitting with many other Beringian disjunctions.

Biogeography of Nymphaeales : extant patterns and historical events

It is hypothesized that subsequent spatial separation and southward relocation of the descendants led to the disjunct distribution of extant sister lineages in core Nymphaeaceae, e.g., Euryale-Victoria or Nymphaea subgg.

Revisiting taxonomy, morphological evolution, and fossil calibration strategies in Chloranthaceae

A reconstructed phylogeny of Chloranthaceae is reconstructed based on a combined dataset of three plastid DNA regions and 56 species and suggests that most intrageneric divisions within Ascarina and Hedyosmum are not monophyletic.

Molecular phylogeny of cycads inferred from rbcL sequences

The rbcL sequences indicate that the colonisation of Madagascar by Cycasthouarsii occurred only recently, and the divergence of the Cycadaceae and Zamiaceae apparently occurred in the Mesozoic, as had previously been assumed.

Paleobotany: The Biology and Evolution of Fossil Plants

This book provides up-to-date coverage of fossil plants from Precambrian life to flowering plants, including fungi and algae, and major groups of land plants both living and extinct.

Phylogenies and angiosperm diversification

Cladistic evidence that Pentoxylon, Bennettitales, and Gnetales are the sister group of angiosperms implies that the angiosperm line (angiophytes) existed by the Late Triassic, and "Tree-thinking" clarifies discussions of the age of groups, by distinguishing between splitting of the stem-lineage from its sister group and splits of the crown-group into extant clades.