11th ICRS Abstract book - Nova Southeastern University

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Use of Molecular Tools To Identify Nongeniculate Coralline Algae
Maria GOMEZ CABRERA* 1 , John PANDOLFI 1
1 Centre for Marine Studies, The University of Queensland, St Lucia, Australia
Oral Mini-Symposium 26: Biodiversity and Diversification of Reef Organisms
Nongeniculate coralline algae (NCA - Corallinaceae, Rhodophyta) are calcified red algae.
They appear as pink to red inflexible crusts. These algae play a ‘keystone’ role in coral
reef structure and functioning by binding reef material and enhancing the settlement of
coral larvae and other species of invertebrates. NCA can also be indicative of specific
habitats and can therefore be an indicator of community structure. Despite their
importance in marine environments, especially coral reefs, this group has been relatively
overlooked due to taxonomic difficulties. Most NCA species cannot be readily
identifiable in situ by their external appearance. Samples must be processed in the
laboratory to access the micro-structures necessary for their identification. Even where
the necessary structures are present, old or damaged specimens cannot be relied upon for
identification purposes. Also the key role of reproductive structures in their identification
is problematic since reproductive plants are not always present in situ.
New molecular tools are emerging that can be used to assist with the identification of
modern NCA. These have been used in conjunction with morphological characters to
identify NCA and to establish possible phylogenies. DNA from morphologically
identified specimens were extracted and several genes (pbsA, nSSU, 23S rRNA and COI)
amplified and sequenced. Preliminary results suggest that a combination of these genes
will give a more accurate relationship at terminal and distal nodes than each of it
separately. pbsA and COI are more variable therefore provide better resolution at species
level. Tests on vegetative plants and damaged specimens were positive. The capacity of
identifying NCA using molecular tools will further ecological studies of these plants,
including the specific role of individual species on the reef and the impact of
anthropogenic influences on them.
26-59
Molecular Phylogeny Of Marine Gobies (Gobioidei: Gobiidae: Gobiinae).
Zeehan JAAFAR* 1 , Rudolf MEIER 1 , L.M CHOU 1
1 Biological Sciences, National University of Singapore, Singapore, Singapore
The family Gobiidae is a speciose group of some 2000 small teleost fishes commonly
known as “gobies”. Whilst some are found in the mangroves and freshwater habitats,
most occur in marine environs and many are coral reef dwellers. The taxonomy and
phylogeny of gobies are problematic due varied forms, behavior, evolution by reduction
and specialization. Phylogeny reconstruction of this sub-family thus far, have been
restricted to morphological characters and limited taxa sampling. This study aims to
elucidate the molecular phylogeny with about 100 representative taxa and four genes;
RAG1, cytochrome b, CO1 and 16S. The most parsimonius phylogenetic tree of marine
gobies is hereby presented. Rapid colonization of the coral reef ecosystem and
specializations, with regards to symbiotic relationships with various coral reef
inhabitants, are shown to have independently evolved several times throughout
evolutionary history.
26-60
The Biogeography Of Damselfish Skull Evolution: A Major Radiation Throughout The
Indo-West Pacific Produces No Unique Skull Shapes
W. James COOPER* 1
1 Biology, Syracuse University, Syracuse, NY
Damselfishes (Pomacentridae, Perciformes) occupy all coral reefs and are known to have
inhabited these ecosystems for at least 50 million years. The Indo-West Pacific (IWP) is
currently home to a large portion of the living damselfish diversity, and contains species from
twenty-four of the twenty-nine extant genera. Phylogeographic evidence indicates that much of
this diversity, including sixteen genera and approximately half of all pomacentrid species,
belongs to a single branch of the damselfish tree that diverged shortly before the closing of the
Tethys seaway 12-18 million years ago. A strong majority of these species can only be found
on coral reefs, and this lineage represents a major radiation of coral reef fishes within this
region. Although this clade constitutes a large component of the damselfish diversity, the
results of morphometric analyses indicate that it does not contain any species with unique
cranial shapes, and the results of permutation tests revealed that the morphological diversity of
the skulls of these fishes is significantly less than that of damselfishes from the other branches
of the pomacentrid radiation. The damselfish skull shapes that are not represented among these
closely related IWP genera belong to fishes that inhabit rocky reefs in other parts of the world.
Many of these species live in temperate waters, and several are considerably larger than their
tropical relatives. If only species from predominantly coral reef genera are compared, then
there is no significant difference in skull shape diversity between fishes from the strictly IWP
genera and damselfishes from other clades. The damselfish radiation can be characterized as
containing numerous examples of morphological and trophic convergence, such that a major
expansion among the coral reefs of the IWP has produced no unique examples of skull
anatomy.
26-61
Planktivory in Genicanthus Angelfishes (F. Pomacanthidae): Reversal Of A Functional
Innovation During Transition Between Feeding Strategies.
Nicolai KONOW* 1 , Peter WAINWRIGHT 2
1 Department of Biology, Hofstra University, Hempstead, NY, 2 Section of Evolution & Ecology,
University of California, Davis, CA
Marine angelfishes of the family Pomacanthidae all have a novel intramandibular joint in the
lower jaw, resulting in a unique gape-closure mechanism which is functionally linked with
trophic shifts into biting dislodgement of robust and sturdily attached reef-building
invertebrates. Never the less, several angelfish taxa are capable of functional reversal to suctionfeeding
– the basal piscine feeding mode – and engage in planktivory. The fact that these taxa
retain the capability of detaching prey from the substratum using a powerful bite suggests that
their jaw mechanics may govern considerable functional versatility. This hypothesis was tested
by comparing feeding apparatus motion during biting and suction feeding in the angelfish
Genicanthus melanospilos with the feeding apparatus motions in an obligate biting sister-taxon
Centropyge (Xiphypops) bispinosus. We found comparable biting motions in these taxa, lending
functional support to their phylogenetic sister-status. Meanwhile, differences between biting
and suction-feeding in Genicanthus exceeded previous measures of vertebrate feeding
behavioural modulation. Intramandibular joint flexion was diminished during suction feeding
and shifts in timing of the jaw-closure stages between feeding modes were key differentiating
variables, suggesting that intramandibular joints actually are disadvantageous for other than
biting feeding activity. Trophic reversal to planktivory commonly occur among coral reef
fishes, e.g. in wrasses, serranids, butterflyfishes and damselfishes, but has not previously been
shown to involve extensive modulation of feeding apparatus motion. Reduction of
intramandibular flexion in Genicanthus during suction-feeding therefore provides an important
example of the close links between structural innovations and associated behavioural changes
that in turn may affect evolutionary diversification. Intramandibular joints may in fact couple
their bearers into biting strategies, thus constraining diversification across alternative trophic
strategies. Herein, the evolutionary role of these novel joints differs from the roles of previously
quantified functional innovations, e.g. in the labroid feeding apparatus, which have prompted
species-radiations by increasing functional versatility.
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