a new species of shell-forming sea anemone from australia andrea l. crowther department of ecology...

A NEW SPECIES OF SHELL-A NEW SPECIES OF SHELL-

FORMING SEA ANEMONE FORMING SEA ANEMONE

FROM AUSTRALIAFROM AUSTRALIA

Andrea L. Crowther

Department of Ecology and Evolutionary Biology

OverviewOverview

• Associations between hermit crabs and

anemones occur in nature

• Hermit crab and Stylobates

• Described species of Stylobates

• New species found from Australia

Hermit crab and anemonesHermit crab and anemones

• Hermit crabs live in

abandoned snail shells

• Anemones attach to shell

• Crabs change shells as

grow, sometimes transfer

anemones

• From shallow tropical

areas to deep sea

• General dynamics of

relationshipshttp://www.divegallery.com/hermit_crab2.htm

StylobatesStylobates

• Deep sea (300-1000 m)

• Always host to hermit crab

• Obligate symbiosis for anemone

• Shell-forming!

• One anemone per crab

Benefits for the symbiontsBenefits for the symbionts

• For the crab

– Protection

– Shell to live in

– Long term

accommodation

• For the anemone– Transport– Food availability

The shellThe shell

• Carcinoecium

• Chitinous secretion

• Anemone coats and

extends hermit crab’s

shell

• Mistaken for a snail’s

shell

http://s190418054.onlinehome.us/portal/2003/0312mon.pdf

Co-evolutionCo-evolution

www.es.ucl.ac.uk/schools/Glossary/gastropod.jpg www.glaucus.org.uk/Hermit4.htm

www.aqualandpetsplus.com.Bug.%20Hermit%20Crabs.htm

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Stylobates aeneusStylobates aeneus

• Original description of

shell

• Anemone discarded!

• Location: Hawaii and

Guam (Pacific Ocean)

• 402-797 m deep

Stylobates Stylobates distributiondistributionStylobates aeneus; Stylobates cancrisocia; Stylobates loisetteae; Stylobates n.sp.

Stylobates cancrisociaStylobates cancrisocia

• Location: East Africa

(Indian Ocean)

• 818 m deep

• 3 specimens

Stylobates loisetteaeStylobates loisetteae

• Location: west coast

of Australia

• 320-508 m deep

• Wide oral disc

• Oral disc position

A new speciesA new species

• Location: north east

Australia

• 680-960 m deep

• 10 specimens

• Size ranging from

5-9 cm length

• Study of morphology

Species comparisonsSpecies comparisons

S. aeneus S. cancrisocia S. loisetteae New species

Locality Hawaii/Guam E. Africa W. Australia E. Australia

Marginal sphincter muscle

Endodermal, circumscribed,

pinnate

Endodermal, circumscribed,

pinnate

Endodermal, circumscribed,

pinnate

Endodermal, circumscribed,

palmate

Orientation on shell

Mouth behind and below aperture of

shell

Mouth near aperture of

shell

Mouth facing away from aperture of

shell

Mouth near aperture of

shell

ReviewReview

• Stylobates anemones are found in the deep sea

• Form associations with hermit crabs

• Produce carcinoecium

• New species found from north east coast of

Australia

AcknowledgmentsAcknowledgments

• Supervisors:

– Dr. Daphne Fautin (KU)

– Dr. Carden Wallace (MTQ, Australia)

• Collectors:

– Dr. Alistair Birtles (JCU, Australia)

– The late Dr. Peter Arnold (MTQ, Australia)

• Sigma Xi

• Questions?