Diversity and systematics of sea anemones Meg Daly Adorian Ardelean Ha Rim Cha

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

Sea Anemones Cnidaria: Anthozoa: Actiniaria This afternoon, I am going to be discussing my recently completed dissertation research, and the research that Daphne Fautin and I are working on now as part of her Peet grant. All of this research involves these creatures, sea anemones or actiniarians. When I began graduate school, I was generally interested in invertebrate zoology and systematics. I chose to focus on sea anemones because they present several intriguing systematic and biological problems. First, although sea anemones are conspicuous, and familiar, our understanding of their anatomy, life history and biology is pretty poor. Most of what we know is concentrated on just a few species, on the animals that are unusually large, or hardy in aquaria, or very widespread. Most anemones have been found once, or maybe twice, and next to nothing is known about their biology or natural history beyond the few anatomical details necessary for a basic species description. Many of the tools that we now use to describe species, like differential interference microscopy, or electron microscopy, which allow us to differentiate between nematocyst types, and much of the insight we have into the way these animals work- like our knowledge of the nervous system, or the behavior and reproductive biology of anemones- have only come to light in the past 40 or so years. This has changed the way we conceive of even well-known taxa. Secondly, there is no real framework for organizing the knowledge that we do have. The systematics of the Anthozoa are pretty bad at the higher level- we are still in the process of defining ordinal boundaries, and many families and perhaps most genera are not monophyletic. The simplicity of the anthozoan body plan, and our limited understanding of it is both cause and effect in terms of the state of systematic knowledge—we know very little about most anemone species, and this makes it hard to understand relationships between taxa, or interpret the variability and range of morphological features. And because we have no real grasp of variability, or homology, it becomes difficult to extend what we do know, or to make meaningful comparisons between taxa. I am going to be discussing these issues in the context of my research one particular family of sea anemones, the Edwardsiidae.

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

Subclass Hexacorallia Antipatharia Actiniaria Actiniaria Ceriantharia Ceriantharia Antipatharia Zoanthidea Scleractinia Zoanthidea Corallimorpharia Scleractinia

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

Overview Anemone diversity & systematics Morphology & variability of Actinodendridae Diversity & systematics of Corallimorpharia

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

Anemone diversity--typical habits Attached to rocks or coral skeletons Intertidal to deep sea In sand or mud

Exotic habits On living hermit crabs or gastropods On jellyfish or comb jellies On living sponges, corals & gorgonians

How does habit(at) manifest itself in morphology or biology? Shape Musculature Reproductive biology Symbionts

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

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

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

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

How can we interpret and understand this diversity?  Taxonomy & systematics

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

Is it the same? Process of comparison Color, habitus, biology & life history Arrangement and morphology of mesenteries & muscles Size, shape & distribution of nematocysts

Why does it matter? Variation in biology and/or role in ecosystem Repeatability and comparability of results

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

Omani Anemones A new species of Heteractis?

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?

Global Diversity of Edwardsiidae • Small burrowing anemones • Poorly known, difficult to collect

Known Distribution

of the sea anemone family Actinodendridae Morphology Variability Systematics of the sea anemone family Actinodendridae

General - morphology long, highly branched tentacles secondary branches primary branch column pedal disc 10 mm

Morphology - acrospheres + simple, pointed Actinostephanus haeckeli + bilobed, narrow Actinodendron arboreum species complex + bilobed, wide Actinodendron alcyonoideum + simple, capitate Megalactis sp.

acrosphere fired capsule Stinging capsules

General - habitat shallow water on sand on sea grass bed among rocks and corals on mud

General - distribution + tropical + Indian and Pacific Ocean and the Red Sea over 400 records

Variability + morphology of tentacles + color and color patterns + nematocysts (stinging capsules) Field research helps to understand variability

Variability - morphology Variant with long: tentacles, branches, acrospheres Actinodendron arboreum elongated tentacle contracted tentacle

Variability - morphology Variant with short: tentacles, branches, acrospheres Actinodendron arboreum

Variability with age + number of branches increases with age + acrospheres are longer in juvenile individuals Actinodendron arboreum juvenile adult

Variability with behavior tertiary branch secondary branch primary branch

Variability - regeneration of tentacles normal secondary branches regenerated secondary branches Actinodendron arboreum

Taxonomy - original descriptions versus reality Actinodendron alcyonoideum (Quoy and Gaimard, 1833) original description vs specimen from Fiji, near Dravuni Isl.

CORALLIMORPHARIA Ha-Rim Cha Vincent B. Hargreaves Adorian Ardelean George Miller CORALLIMORPHARIA Ha-Rim Cha The Natural History Museum and Biodiversity Research Center The University of Kansas Lawrence, KS, USA

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)

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)

What do they look like? Cylindrical body Family Sideractiidae Danielssen, 1890 Family Corallimorphidae Hertwig, 1882

Corallimorpharia from Red Sea Eilat Reef, Israel Discosoma unguja Discosoma nummiforme Rhodactis rhodostoma (photos by Baraka Kuguru)

Predictive Range Modeling Discosoma nummiforme SST_mean_monthly, SST_min_max_range, Salinity_ann_avg, Chlora, Tides