Diversity and systematics of sea anemones

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Diversity and systematics of sea anemones

• Meg Daly
• Adorian Ardelean
• Ha Rim Cha

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Acknowledgments

• Michel Clareboudt, staff faculty of Marine
  Sciences, SQU
• Daphne Fautin
• American Association for the Advancement of
  Science, National Science Foundation, KU Natural
  History Museum Biodiversity Research Center

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Sea AnemonesCnidaria Anthozoa Actiniaria
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Sea Anemones

• Cnidaria
• 2 layered, organ-less body, with stinging
  nematocysts
• Anthozoa
• Polyp form only
• Actiniaria
• Skeleton-less, solitary or clonal (not colonial)

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Subclass Hexacorallia
Antipatharia
Actiniaria
Ceriantharia
Antipatharia
Actiniaria
Ceriantharia
Zoanthidea
Scleractinia
Corallimorpharia
Zoanthidea
Scleractinia
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Why study anemones?

• Diverse in habitat, biology, life history
• Understand evolution of colonies and skeletons
  among Anthozoa
• Understand evolution of tissues, organs, and
  polarity in animals

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Overview

• Anemone diversity systematics
• Morphology variability of Actinodendridae
• Diversity systematics of Corallimorpharia

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• Systematics Diversity of Actiniaria
• Diversity
• Habitat
• Biology
• Life history
• Systematics
• Identification
• Morphology
• Molecules
• Role of Biodiversity Studies
• Evolution
• Biogeography

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Anemone diversity--typical habits

• Attached to rocks or coral skeletons
• Intertidal to deep sea
• In sand or mud
• Intertidal to deep sea

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Exotic habits

• On living hermit crabs or gastropods
• On jellyfish or comb jellies
• On living sponges, corals gorgonians

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How does habit(at) manifest itself in morphology
or biology?

• Shape
• Musculature
• Reproductive biology
• Symbionts

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Shape

• Burrowing forms tend to be long, slender, smooth
• Intertidal forms are often bumpy with suckers
  that hold stones
• Deep water forms tend to be thick, stout, with
  wide oral discs

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Musculature

• Burrowing forms have strong retractor and
  circular muscles, weak basilar muscles
• Intertidal forms have strong marginal sphincters
• Attached forms have weak circular and retractor
  muscles

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Reproduction

• Attached forms in shallow subtidal and in deep
  sea have free swimming larvae, deep sea forms may
  have very large larvae
• Attached forms undergo longitudinal fission,
  burrowing forms undergo transverse fission

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Symbionts

• Photosymbionts in attached and burrowing forms in
  shallow water
• Photosymbiotic forms have broad oral disc
• Crab symbionts tend to have potent nematocysts

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How can we interpret and understand this
diversity?

• ? Taxonomy systematics

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What is it?Process of identification

• Find specimen
• Compare multiple specimens
• Develop sense of range of variation in color,
  shape morphology
• Compare to descriptions of similar known species

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Is it the same?Process of comparison

• Color, habitus, biology life history
• Arrangement and morphology of mesenteries
  muscles
• Size, shape distribution of nematocysts

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Why does it matter?

• Variation in biology and/or role in ecosystem
• Repeatability and comparability of results

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Biodiversity in Oman

• Components of the tropical Indo-Pacific fauna
• New species (possibly endemic)
• Lacking representatives of Acontiaria

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Omani Anemones
A new species of Heteractis?
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Anthopleura biogeography and evolution in the
intertidal zone

• What role do history, geography, or habitat play
  in
• loss or re-acquisition of asexual reproduction?
• loss, change, or re-acquisition of
  photosymbionts?

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Global Diversity of Edwardsiidae
Small burrowing anemones Poorly known,
difficult to collect
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Known Distribution
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Morphology Variability Systematics of
the sea anemone family Actinodendridae
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General - morphology
long, highly branched tentacles
secondary branches
primary branch
column
pedal disc
10 mm
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Morphology - acrospheres
simple, pointed
Actinostephanus haeckeli
bilobed, narrow
Actinodendron arboreum species complex
bilobed, wide
Actinodendron alcyonoideum
simple, capitate
Megalactis sp.
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acrosphere
fired capsule
Stinging capsules
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General - habitat
shallow water
on sand
on sea grass bed
among rocks and corals
on mud
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General - distribution
tropical Indian and Pacific Ocean and the
Red Sea
over 400 records
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Variability
morphology of tentacles color and color
patterns nematocysts (stinging
capsules) Field research helps to understand
variability
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Variability - morphology
Variant with long tentacles, branches,
acrospheres
Actinodendron arboreum
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Variability - morphology
Variant with short tentacles, branches,
acrospheres
Actinodendron arboreum
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Variability with age
number of branches increases with age
acrospheres are longer in juvenile individuals
Actinodendron arboreum
adult
juvenile
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Variability with behavior
tertiary branch
secondary branch
primary branch
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Variability - regeneration of tentacles
Actinodendron arboreum
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Taxonomy - original descriptions versus reality
Actinodendron alcyonoideum (Quoy and Gaimard,
1833) original description vs specimen
from Fiji, near Dravuni Isl.
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CORALLIMORPHARIA
Vincent B. Hargreaves
Adorian Ardelean
George Miller

• Ha-Rim Cha
• The Natural History Museum and Biodiversity
  Research Center
• The University of Kansas
• Lawrence, KS, USA

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Corallimorpharia

• One of six orders of Zoantharia
• Coral-like sea anemones
• Solitary or colonial polyps without skeleton
• Current Classification four families, 13
  genera, and 50 species
• Widely distributed from tropical to polar areas
  and from shallow to deep water
• Questions in the classification and the
  phylogenetic relationships

LeRoy (http//www.garf.org)
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What do they look like?

• Plate-like body
• Family Ricordeidae Watzl, 1922
• Family Discosomatidae Duchassaing de Fombressin
  and Michelotti, 1864

(Photos by Vincent B. Hargreaves)
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What do they look like?

• Cylindrical body
• Family Sideractiidae Danielssen, 1890
• Family Corallimorphidae Hertwig, 1882

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Corallimorpharia from Red Sea
Eilat Reef, Israel
Discosoma unguja
Discosoma nummiforme
Rhodactis rhodostoma
(photos by Baraka Kuguru)
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Predictive Range Modeling
Discosoma nummiforme
SST_mean_monthly, SST_min_max_range,
Salinity_ann_avg, Chlora, Tides