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Title: More questions:

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  • More questions
  • What are the closest relatives of the
  • Is the order Trentepohliales a monophyletic
  • What evolutionary processes have occurred within
    the Trentepohliales?

  • Two lineages in Viridiplantae
  • Trentepohlialean taxa are unequivocally within
    the chlorophycean lineage
  • The order Trentepohliales is included within the
    ulvophycean taxa
  • The order Trentepohliales is a monophyletic
  • Phragmoplast?

Relationships within the Ulvophyceae
  • The marine orders are the most closely related
    to the Trentepohliales
  • In all phylogenetic analyses the
    Trentepohliales emerged as a sister group to the
    clade containing the Siphonocladales/Cladophorales
    complex and Dasycladales, both containing
    representatives mainly from the marine

  • Relationships within the Trentepohliaceae
  • What about the relationships inside of the
  • Are the genera monophyletic?
  • Is the species Cephaleuros virescens, with a
    world-wide distribution, a monophyletic taxon?
  • What is the validity of several morphological
    characters used for separation at species and
    genus level?

Relationships within the Trentepohliaceae
  • Four main lineages in 18S rDNA
  • Cephaleuros clade
  • Printzina lagenifera clade
  • Trentepohlia aurea clade (the generitype)
  • Trentepohlia iolithus clade
  • Molecular data challenge traditional
    classification schemes

Relationships among Trentepohlialean genera
On the basis of our results, Cephaleuros forms a
well-defined monophyletic group, representing a
more advanced clade Conversely, Trentepohlia is
non monophyletic and the other genera included in
the analyses do not represent separate lineages,
suggesting the possibility that a major
rearrangement at the genus level may be necessary
in the future
  • Printzina was proposed as a new genus for nine
    species previously belonging to Trentepohlia
  • The shape of the sporangia, the arrangement of
    the sporangiate-laterals, the extensive
    development of the prostrate parts of the thallus
    and the occurrence in shaded habitats were
    considered the key characters separating
    Printzina from Trentepohlia
  • The only feature that separates conclusively the
    two genera is the shape of the sporangia
  • globular to reniform in Printzina
  • ovoid in Trentepohlia)

The position of Phycopeltis is surprising Importa
nce of the position of the ostiole in the
zoosporangium as key character T. umbrina (as P.
umbrina) with an ostiole opposite to the end of
attachment too T. abietina from Hawaii shows the
ostiole clearly opposite to the end of
attachment Our results provide therefore some
evidence that the position of the ostiole may be
a good phylogenetic marker
Relationships within a species Cephaleuros
  • Cephaleuros virescens Kunze, the generitype of
    Cephaleuros, is generally considered to have a
    worldwide distribution in tropical and
    subtropical regions
  • Strains of C. virescens do not form a
    monophyletic group South Africa and Taiwan are
    more closely related to C. parasiticus than to
    other C. virescens

Current analyses using the chloroplast-encoded
rbcL marker confirm 18SSU results
  • These data suggest that the circumscription of C.
    virescens should be reconsidered
  • Morphological characters used to separate this
    species form similar taxa should be reassessed
  • As currently circumscribed, C. virescens
    represents a complex of morphologically similar
  • Suriname is the type locality of C. virescens,
    the actual distribution of this species might be
    restricted to tropical South and Central America

Lessons learned
  • A subaerial habit has developed within the class
  • Morphological criteria traditionally used for
    the circumscription of genera and species of
    Trentepohliales are not correlated with
    evolutionary patterns
  • Common and world-wide distributed species may
    represent a species complex of morphologically
    similar entities (cryptic species)
  • Many morphological characters used in taxonomy
    are not phylogenetically relevant
  • Another subaerial lineage has been found from a
    group containing representatives mainly from the
    marine environment

Evolution of the subaerial flora
From textbooks to popular articles there is an
appreciation that terrestrial life emerged from
the seas. And there is generally no explanation
that by seas is meant from oceans and lakes
that is, from both marine and freshwater sources
Several representatives of the marine green
algal class Ulvophyceae have been found to be
members of the terrestrial algal flora
The order Trentepohliales and our newly
described taxa are examples of a direct marine
invasion of terrestrial environments! This is in
contrast with the general idea that terrestrial
floras are descendents of freshwater ancestors
and not directly from marine ancestors A direct
marine invasion?
  • One intriguing, even puzzling, question is
  • How marine algae, from ulvophycean ancestors,
    jump into terrestrial habitats and became
    permanent representatives of the land flora?
  • A probable answer may came from independent bits
    of information
  • Fossils
  • Ancient changes of sea level
  • Pre-adaptive phenotypic plasticity

Fossil subaerial microchlorophytes
Records of fossils belonging to terrestrial
microchlorophytes have been found as early as the
late Eocene (ca. 50 mya)
Reynolds and Dilcher 1984 As Cephaleuros
parasiticus Re-described as an alga Later
transfer to C. villosus By Thompson Wujek 1997
Dilcher 1965 As Pelicothallus villosus Described
as a fungus
Fossil trentepohlialean taxa have been reported
from the German Eocene
Trentepohlia aurea
Trentepohlia diffusa
Koeck 1939 Fossilie Kryptogamen aus der eocanean
Barunkohle des Geiseltales. Nova Acta Leopoldina
Printz 1939 Vorarbeiten zu einer Monographie der
Trentepohliaceen.S. Nytt Mag. Aturvidenskapene B.
80137-210, Taf.I-XXXII
Trentepohlia aurea var. acutata
Trentepohlia rigidula
Koeck 1939 Fossilie Kryptogamen aus der eocanean
Barunkohle des Geiseltales. Nova Acta Leopoldina
Printz 1939 Vorarbeiten zu einer Monographie der
Trentepohliaceen.S. Nytt Mag. Aturvidenskapene B.
80137-210, Taf.I-XXXII
  • Reliable fossil records established
    trentepohlialean floras as far as the Eocene 50
  • By the end of this epoch
  • Continents moved closer to their present
  • Tropical areas shrinking
  • A drying period commences
  • In subtropical latitudes, open woodlands with
    ferns and shrubby plants replaced forests
  • Whale ancestors left the land
  • Trentepohlialean taxa appeared on land over 400
    my after the initial colonization of land plants
    in the Paleozoic (480 mya)

Ancient sea level changes
  • Just before Eocene (50 mya) the sea level was at
    the highest and since then it has been receding
  • Much of continental North America, Africa and
    Australia were exposed

Falkowsky et al. 2004 sea level change
  • Evolution of floras such as
  • Diatoms
  • Grasses

Falkowsky et al. 2004 sea level change
Pre-adaptive phenotypic plasticity
  • Intertidal marine algae live in a variable
    environment under great physical stress
  • This may lead to a selection for a plastic
    morphology were the same genotype is expressing
    several morphologies under different ecological
  • Extant ulvophyceans are examples of this
    adaptive phenotypic plasticity

Terrestrial ulvophytes express this adaptive
phenotypic plasticity by their ecological
ubiquity, ability to grow in several media, and
their astonishing capacity to undergo
morphological modifications
Information from fossils, ancient sea level
changes, phenotypic plasticity and molecular data
seem to indicate that
  • Terrestrial ulvophytes did not jump from
    marine to terrestrial habitats they were left
    behind after sea levels receded during the
  • Ancestors of terrestrial ulvophytes may had the
    pre-adaptive capabilities to exploit and
    diversify in the new habitat and become permanent
    members of the subaerial flora

  • Many questions still remain to be answered, for
  • Exclusively subaerial algae have a long
    evolutionary history compared to other green
    algal orders however, their fossil evidence is
    relatively more recent what is the evolutionary
    history of this lineage between their ancestral
    marine origin and their transition to land?

  • Many questions still remain to be answered, for
  • Exclusively subaerial algae have a long
    evolutionary history compared to other green
    algal orders however, their fossil evidence is
    relatively more recent what is the evolutionary
    history of this lineage between their ancestral
    marine origin and their transition to land?
  • Another intriguing question is about evolutionary
    reversals are there any examples of algae that
    originated in the continental environment and
    made a transition back to the sea?

  • Some conclusions
  • The terrestrial habitat has been colonized by
    several lineages and more than one green algal
  • The Charophycean, Trebouxiophycean and
    Chlorophycean algae made attempts to colonize the
    Land via freshwater habitats
  • The marine Ulvophycean taxa also made this
    conquest (at least twice)
  • Subaerial ulvophytes conquered the land using a
    direct strategy
  • The history of the conquest of terrestrial
    habitats by algae is more complex than previously
  • New molecular techniques (environmental cloning
    and phylogenomics) may unravel more unknown
    lineages and unexpected discoveries!

  • Acknowledgments
  • Russell L. Chapman, Scripps Institution of
  • Mike Guiry, National University of Ireland
  • Paul Broady, University of Canterbury, New
  • Thomas Friedl, University of Goettingen
  • Fred Brooks, American Samoa Community College
  • Alison Sherwood, University of Hawaii at Mãnoa
  • Joe Zuccarello, Victoria University of
    Wellington, NZ
  • Bruno De Reviers, Paris Herbarium
  • Ricardo Tsukamoto, Sao Paulo, BZ
  • Jirí Neustupa, Charles University of Prague,
    Czech Republic

Drs. Fabio Rindi and Sarah M. Noble, graduate
students Daryl W. Lam and Haj A. Allali, several
Research at the Phycolab is funded by grants from
NSF Systematics-DEB, NEP, MASGC, CAS/UA and from
a RAC/UA to JLB Fieldwork funds to French
Guiana, South Africa, Gabon, Panama, Suriname,
Europe, and Southern Mexico partially provided by
the Graduate School and the Department of
Biological Sciences at UA
The PhycoLab in the Web
Ongoing Research at the PhycoLab
Subaerial microchlorophytes
Southeastern USA
French Guiana
South Africa
and Australia
Assembling the Tree of Life Program
UA CUBA Seaweed research collaboration
Lidice Clero, CIM
Dr. Ana Maria Suarez Inst. Marine
Sciences University of La Havana
M. Sc. Ruben Cabrera Marine Archeology
Yusimi Alfonso, Acuario Nacional
Mayrene Guimaraes, Cayo Coco
Antonio Vega, Holguin
Sandra Siret, Matanzas
Abdiel Jover, Santiago
Angel Moreira, Cienfuegos
Juan J. Lake, Camaguey
Dr. Beatriz Martinez Oceanology Institute, CITMA
Ivan Martin, Villaclara