Sunday, 9 November 2014

Sunday's Nudibranch: Jorunna funebris

Jorunna funebris, black and white nudibranch
 Jorunna funebris
Photo by © Mark Rosenstein  [CC BY-NC-SA 3.0]
Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Superfamily: Doridoidea
Family: Discodorididae
Genus: Jorunna
Species: Jorunna funebris
Common Name: Dotted nudibranch, Polka Dot

When I was writing my "14 Most Amazing Nudibranchs" post I had a really hard time choosing which species to include and which not.

This animal group is very diverse and full of beautiful, alien-like or simply weird looking creatures. One post can't make them enough justice.

So, from now on, every Sunday I will introduce you to a different species of nudibranch. Usually there is little research on individual species and as a result the posts will be short in information but rich in photos and images. Hope you enjoy them.

Today's nudibranch is Jorunna funebris which for some reason reminds me of Oreos.

Distribution & Habitat
The Dotted nudibranch occurs in the Red Sea and in the Indian Ocean along East Africa. It inhabits seagrass meadows, coral rubble, and coral reefs and can be found in depths ranging from 10 to at least 21 meters. 

Adults have an oval body and are 2 to 6 cm long. They are easily identified by their white body and random black-brown spots, made of tiny tubercles which give them a fuzzy appearance.

The six, black-brown branched gills form a complete circle around the anus.

Credit: By Steve Childs from Lancaster, UK (Flickr)
[CC-BY-2.0], via Wikimedia Commons

The species has been recorded to feed on blue sponges (Neopetrosia sp.).

The Dotted nudibranch is a hermaphrodite that lays egg masses. .The genital openings lie on the right side of the body, so they have to position themselves side-by-side in opposite directions before mating.

 In captivity, the egg masses ranged from 17.1–48.0 cm in length, and between 0.4 cm and 0.7 cm in width. The density of egg capsules varied from 27–64 egg capsules/mm2 of egg mass with each egg capsule having 1 to 4 larvae inside.

Two Jorunna funebris having some sexy time
Mating Jorunna funebris
Credit: © Ria Tan, [CC BY-NC-SA 2.0]

More Photos and Videos

Purple Jorunna funebris
Credit: By Katia Ferrer
[CC-BY-SA-3.0], via Wikimedia Commons
Jorunna funebris (polka dot) nudibranch
Photo taken in Jorunna Funebris, Shark Island, Ko Tao, Thailand
Credit: By yeowatzup from Katlenburg-Lindau, Germany
[CC-BY-2.0], via Wikimedia Commons
Jorunna funebris in Thailand
Credit: Marine Life in the Koh Phangan vicinity, Thailand
[CC BY 3.0]
Beautiful Jorunna funebris (Lautem, East Timor)
Credit: Nick Hobgood, Location: Lautem, East Timor
[CC BY-NC 2.0]
Credit: Nick Hobgood
[CC BY-NC-SA 3.0]

Video shot in Sailrock, Thailand

Location:  Seth's Point, Kapota Island, Wakatobi, South East Sulawesi, Indonesia

Jorunna funebris feeding on blue sponges

References & Further Reading
- Pattira Kasamesiri, Shettapong Meksumpun, and Charumas Meksumpun (2012). Observations on Embryonic Development of Black-Spot Jorunna, Jorunna Funebris (Kelaart, 1859) (Gastropoda: Nudibranchia) Journal of Shellfish Research, 33 (2), 111-117 :
- Camacho-Garcia, Y., & Gosliner, T. (2008). Systematic revision of Jorunna Bergh, 1876 (Nudibranchia: Discodorididae) with a morphological phylogenetic analysis Journal of Molluscan Studies, 74 (2), 143-181 DOI: 10.1093/mollus/eyn002
- Ng, P. K. L., S. S. L. Lim, L. K. Wang & L. W. H. Tan, 2007. Private Lives: An Exposé of Singapore's Shores. Raffles Musem of Biodiversity Research. 212 pp.
- Tan Siong Kiat and Henrietta P. M. Woo, 2010 Preliminary Checklist of The Molluscs of Singapore (pdf), Raffles Museum of Biodiversity Research, National University of Singapore.

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