Images 1 and 2: Living pluteus larva of the sea biscuit Clypeaster subdepressus under polarized light microscopy. Only the skeleton remains visible. Photos by Bruno C. Vellutini (Wikimedia; Flickr); cc-by-sa

Image 3: Pluteus larva via ccNeLaS

Image 4: Developing pluteus larva. Via Wikimedia. Public domain

Image 5: Sea urchin development tattoo via The Loom

Caption: “Greetings! Here’s a pic of my science tat. I studied sea urchin development for my dissertation. Upon completion 2 yrs ago, I awarded myself this tat for my academic achievement. The tat is of a sea urchin egg, 2 cell embryo, blastula, gastrula, prism stage and pluteus larval stage. Or as my friend’s say, an orange developing into an Alien face-grabber.”

Actinotroch of Phoronis vancouverensis

From Invertebrate Embryology blog

Caption: “These pictures are stacks of confocal images of two different actinotroch larvae of the horseshoe worm Phoronis vancouverensis (Phylum Phoronida). P. vancouverensis is a rather inconspicuous phoronid which lives in small (a few centimeters long) muddy tubes in clumps, attached to some sort of hard substratum (a rock, a floating dock) often in somewhat muddy surroundings. This species broods its larvae in the crown of tentacles, called the lophophore. I gently shook the larvae out of the lophophore of an adult and prepared them for confocal microscopy with my students while teaching the Comparative Embryology course at the Friday Harbor Labs in the Summer 2007.

We preserved the larvae and stained them with fluorescent phallodin (a toxin, derived from the deathcap mushroom Amanita phalloides), which binds to filamentous actin. Muscles are highlighted because they are full of actin, a protein which enables cellular contractility. So, most of what you see on these pictures are muscle fibers. There is also quite a bit of actin in the cell cortex (the region of the cytoplasm adjacent to the plasma membrane). So, the outlines of epidermal cells are often also labeled with phalloidin.”


For such tiny animals, Syllidae really get around.

These polychaete worms, most only a few millimeters long, are found from the intertidal to the deep sea. The over 200 species of Syllids, and potentially many more not yet recognized, are keeping some molecular biologists very busy. 133 species from 5 continents have DNA barcodes already, and our colleagues at the Moorea Biocode project just keep finding more, just waiting to be identified, or classified as new species.

More Syllids from Moorea here.

(via: Encyclopedia of Life)

Terrifying (but tiny!) bryozoans

Images 1 and 2: Beania mirabilis (source) cc-by-nc-sa

Image 3: Electra monostachys (source) cc-by-nc-sa

Image 1: “Scanning electron microscope image of a bryozoan colony” (Source)

Image 2: “This skeleton of a living bryozoan, collected at Bahia de los Angeles, Baja California, clearly shows this typical colonial organiation.

Each individual, or zooid, is enclosed in a sheath of tissue, the zooecium, that in many species secretes a rigid skeleton of calcium carbonate. Each zooid in this electron micrograph is less than a millimeter long and has a single opening, the orifice. Through this opening, the lophophore, a ring of ciliated tentacles centered on the mouth, protrudes to capture small food particles. The lophophore can be retracted very rapidly by specialized retractor muscles, and the opening closed by a doorlike operculum, visible on some of the zooids in the picture at the left.”


Image 3: Membraniporella nitida (source) cc-by-nc-sa

More info:

Pygites brachiopods… or bizarre fossil scrotal phylogeny?

Images 1 and 2: Source. In German. 

Image 3: Source

Caption: “Pygites is unusual for a Terebratulid brachiopod. It shares many of the same features that other brachiopods in it’s order except that it has a hole in the middle of it. The hole is created as the shell grows and splits into lobes that then eventually meet back together and enclose a hollow area. This is odd behavior for a brachiopodand I’ve only seen a handful of genera that have even exaggerated lobes, such as Dicoelosia from the Haragan formation, let alone those that surround a hole. Below are three specimens from the Cretaceous (Hauterivian stage) of Spain that show you the variation in the genera.”

Image 4: ”Pygites diphyoides (d’Orbigny, 1849) from the Hauterivian (Lower Cretaceous) of Cehegin, Murcia, Spain. This terebratulid is characterized by a central perforation through its valves.” Source: Wikipedia; cc-by-sa

Image 5: Pygites diphyoides (source)

More brachiopods! The spiral lophophores are a filtering apparatus. 

Image 1: “Fig. 8. Hypothetical representation of efficiency of the filtering system of some extinct spire-bearing brachiopods showing flow patterns and extension of area for trapping food resources. Inhalant and exhalant currents according toVogel (1975) and diagram modified from Ager and Riggs (1964).”

Image 2: “Fig. 9. Hypothetical representation of efficiency of the filtering system present in extinct productid brachiopods showing flow patterns and extension of area for trapping food resources. Inhalant and exhalant currents as in a similar model proposed for Falafer Grant (1972) and diagram modified from Brunton et al. (2000) without including his interpretations.”


Pérez-Huerta and Sheldon. 2006. “Pennsylvanian sea level cycles, nutrient availability and brachiopod paleoecology.” Palaeogeography, Palaeoclimatology, Palaeoecology. Volume 230, Issues 3–4, 30 January 2006, Pages 264–279.

More brachiopods! The spiral lophophores are a filtering apparatus. 

Image 1: Brachiopod, (image source)

Image 2: Magellania, an articulate brachiopod (source)

Image 3: Group of brachiopods. (Source). The coolest one is “E”:

Notosaria nigricans E. Brachial interior with spirolophous lophophore 


Sounds like we have a word (or phrase) of the day!

More brachiopods! The spiral lophophores are a filtering apparatus. 

Image 1: Liospiriferina rostrata (jr synonym Spiriferina rostrata) (Brachiopod). Brachiopods filtered plankton, using a specialized organ: the lophophore. It is exceptional to be able to find silicified skeleton of this organ, visible in this specimen.” via Wikipedia (image source) cc-by-sa

Image 2: Spiriferina brachiopod fossil. Science Photo Library