MOLECULAR SYSTEMATICS AND CRYPTIC DIVERSITY OF THE GENUS
DICTYOTA (DICTYOTALES: PHAEOPHYTA) WITH SPECIAL REFERENCE TO
SPECIES OCCURRING IN THE PHILIPPINES
Payo D io li Ann
E co lo g ica l M a rin e M a n a g e m e n t P rogram m e (E C O M A M A ), V rije U niversiteit Brussel
P leinlaan 2 , B -1 0 5 0 Brussel, Belgium
H u id ig adres: Venus A lley, Blk. 2 7 lot 3 2 Phase 2B V & G s u b d ., 6 5 0 0 T a c lo b a n C ity, Leyte,
Philippines
E -m ail: d io li_ 2 0 @ y a h o o .c o m
In o rd e r to study the m o le cu la r sytematics and cryptic diversity o f the brown m a cro a lga l
genus, D ictyota
inventory
(Dictyotales:
o f the
D ictyota
Phaeophyta), 3 objectives were set:
species
o ccurring
in
the
Philippines;
1. to
2.
to
m ake an
determ ine
congruence between m o rp h o lo g ica l and phylogenetic species concepts; 3. to study
cryptic diversity in the D ictyota d ichotom a com plex. This thesis puts special emphasis on
P hilippine D ictyota species.
Inventory and m o rp h o lo g ica l exam ination o f specimens collected in the islands o f
Visayas in the Philippines revealed that at least 7 species o f D ictyota can be found in the
region. The species identified were the fo llo w in g : Dictyota bartayresiana Lam ouroux, D.
ca na licu la ta De C lerck & C o p pe ja ns, D. cervicornis Kütz., D. ceylanica Kütz, D. ciliolata
Sond. ex Kütz, D. crispata J.V. Lam our and D. friabilis Setchell. D ictyota dichotom a
which had been frequently reported from several localities th ro u g h o u t the Philippines
was not encountered d uring the present study. De C le rck (2003) seriously doubted the
presence o f the generitype, D. d ichotom a (originally described from England) in tro pical
latitudes.
The phylogenetic analyses (focusing on M axim um like lih o o d tree outputs) used the LSU
nrRNA gene, the
plastid
encoded
rbcL gene, and
interleaved
n rR N A - LSU gene
sequences o f D ictyota species and o th e r Dictyotaceae taxa as outgroups. The total
num bers o f taxa used fo r each dataset were 4 4 , 3 5 , and 2 9 taxa, respectively. A pa rt
from
Philippine sam ples, sequences were obta in ed
from
D ictyota and
Dictyotales
specimens from several different g e o g ra p h ic regions. Some sequences deposited in
G E N B A N K were also included in the analyses.
The fam ily D ictyotaceae, the largest in the o rd e r D ictyotales, is subdivided into two
tribes: Dictyoteae and Z o na riae . The Dictyoteae are recognized by the single lens
shaped a pical cell as opposed to a row o r g ro u p o f a pical cells found in the Z onariae.
Scoresbyella, the only genus o f Scoresbyellaceae and characterized by a w edge shaped
vertically oriented a pical cell, appears closely related to the Dictyoteae in the analyses.