The sea dragon slug (Pteraeolidia ianthina): steals stinging cells and photosynthetic symbionts from its prey — while looking super fancy!

Pteraeolidia ianthina, one of the most common aeolids found, is often called a “blue dragon” by Eastern Australian divers because of its close resemblance to a Chinese dragon.[4] It is one of the most common aeolid nudibranchs found in Eastern Australia. It can inflict a painful sting to humans.

The slug is very elongated (7 cm) with many clusters of medium-large sized cerata along the length of the body. The fat rhinophores and the long cephalic tentacles have at least two dark purple bands that stand out. The tips of the cerata contain nematocysts.

Symbiotic zooxanthellae continue to photosynthesise inside the body and give rise to brown and green pigments. The zooxanthellae, together with the nematocysts, are presumed to be derived from coelenterate prey. These zooxanthellae occur within vacuoles in host cells derived from the endoderm.[5]

“This sea slug has evolved the ability to harness the sun’s energy for its own use. This is possible because the slug feeds on hydroids which contain symbiotic zooxanthellae, microscopic dinoflagellates that are photosynthetic — in other words that have the capability to make sugars from sunshine. The nudibranch farms these zooxanthellae within its own digestive diverticula. The zooxanthellae then convert the sun’s energy into sugars. The sugars are used by the slug.[7]

Image 1: Blue Dragon – Pteraeolidia ianthina

Tooth Brush Island. Flickr user billunder, 2009:

Image 2: Blue Dragon – Pteraeolidia ianthina

Flickr user billunder, Australia, 2009:

Blue Dragon – Pteraeolidia ianthina

Image 3: Sea dragon slug (Pteraeolidia ianthina), GBR, Australia

Photo by Arthur Anker:

Cosmarium botrytis, a freshwater alga

More info:

The vast majority of these illustration plates are from a plant systematics wall chart series – the Dodel-Port Atlas – released between 1878 & 1883”


Waltzing Volvox, from the Goldstein Lab at the University of Cambridge

Volvox is a colonial green algae (more info at Wikipedia)

Check out more movies on their YouTube channel and lab website

(And someone else has uploaded a more colorful video of dancing volvox here:

Volvox, a colonial green algae (more info at Wikipedia)

From the Goldstein Lab, Department of Applied Mathematics and Theoretical Physics, University of Cambridge:

They do really, really cool research, as described by this awesome statement: 

When asked whether I am a theorist or an experimentalist, my reply is that I am a scientist. Our group seeks to understand fundamental principles that govern the behavior of nonequilibrium systems in physics and biology, using a combination of experiment and theory. This research is not easily described by a single, conventional academic label; rather, it involves the domains of condensed matter physics, physical chemistry, biological physics, fluid dynamics, applied mathematics, and geophysics.  I subscribe to Poincaré’s motivation: 

The scientist does not study nature because it is useful;

he studies it because he delights in it, and he delights in it because
it is beautiful. If nature were not beautiful, it would not be worth knowing, and if nature were not worth knowing, life would not be worth living.

I also believe that some of the best science is close to art, and that Glenn Gould captured this spirit when he said 

The purpose of art is not the release of a momentary ejection of adrenaline but rather the gradual,
 lifelong construction of a state of wonder and serenity.”

UMMM and they have a YouTube channel!

Volvox globator, a colonial green algae (more info at Wikipedia)

The vast majority of these illustration plates are from a plant systematics wall chart series – the Dodel-Port Atlas – released between 1878 & 1883”


Volvox, a colonial green algae

From Wikipedia

“Volvox is the most developed in a series of genera that form spherical colonies.[1] Each mature Volvox colony is composed of numerous flagellate cells similar to Chlamydomonas, up to 50,000 in total,[2] and embedded in the surface of a hollow sphere or coenobium containing an extracellular matrix[2] made of a gelatinous glycoprotein.[3] The cells swim in a coordinated fashion, with distinct anterior and posterior poles. The cells have eyespots, more developed near the anterior, which enable the colony to swim towards light. The individual algae in some species are interconnected by thin strands of cytoplasm, called protoplasmates.[4] They are known to demonstrate some individuality and working for the good of their colony, acting like one multicellular organism.”

Image 1Volvox aureus, by Dennis Kunkel (2002):

Image 2: From Wikipedia, by Frank Fox (; cc-by-sa

Image 3: From Wikipedia, cc-by-sa

Image 4: Life cycle of Volvox carteri:

Buckminster Fuller, Laminar Geodesic Dome, United States Patent Office no. 3,203,144, from the portfolio Inventions: Twelve Around One, 1981; screen print in white ink on clear polyester film; 76.2 cm x 101.6 cm; Collection SFMOMA, gift of Chuck and Elizabeth Byrne; © The Estate of R. Buckminster Fuller, All Rights reserved; image courtesy SFMOMA.


Ceramium spp. and a bonus Callithamnion sp. (red algae)

Image 1: Source: Algaebase

Caption: Ceramium juliae, Morris Point, Stilbaai, South Africa. 31 Oct 2001. Herre Stegenga. © Herre Stegenga 

Image 2: Source: Algaebase

Caption: Ceramium mazatlanense. Hawaii; scale 300 µm. 15 Aug 2011. J.M. Huisman. © J.M. Huisman.

Image 3: Source: WoRMS (cc-by-nc-sa)

Caption: Ceramium pallidum

Description: microscope, location: Spain, Galicia, Coruña, Pantín’s beach, 2007
AuthorBárbara, Ignacio
JPG file – 1.22 MB – 1000 x 1350 pixels
added on 2008-03-19 – 356 views
WoRMS Taxa on this image: 
Ceramium pallidum (Nägeli ex Kützing) Maggs & Hommersand, 1993

Image 4: Ceramium ciliatum © C. Romero Zarco – Universidad de Sevilla, 2003

Image 5: Callithamnion sp., same source as Image 4