Note: See previous post on December 9

In my prior post, I talked about how sea slugs sense their environments using rhinophores (horn-like appendages on their heads). In this post, I will describe how sea slugs get oxygen from their environments. Unlike land slugs, which use lungs to breathe, sea slugs breathe using their gills. Like the rhinophores, the gills of sea slugs come in a variety of shapes, sizes, and colors, and are often used in identification and classification. The gills can be quite beautiful and ornate, giving each slug a unique appearance. The gills are usually located on the backs or the sides of their bodies. However, there are exceptions to this. Sea hares, a group of sea slugs that have rhinophores resembling rabbit ears, have gills found deep within the body cavity.

Most dorid nudibranch sea slugs possess a feather-like plume on their backs, which surround their anus. Yes, they breathe in the same region of their bodies in which they poop! Despite this, the gills provide the slugs with enough oxygen from the water for them to survive. Some dorids, in the group cryptobranchia, can pull their gills into a pocket on the surface of their bodies. The name cryptobranchia describes their ability to do this. When touched or threatened, the gills will retract into the body as a form of protection.

Some slugs lack well-defined gills. Instead, gas is taken in through the tissue of specialized body appendages. These include cerata, which are finger-like appendages that run along the backs of the slugs in distinctive rows. These cerata come in an assortment of shapes, sizes, and colors depending on the species. These appendages are elongate to increase the surface area through which oxygen can be absorbed. The gills of some nudibranchs are tree-like in appearance. Each branch aids in the uptake of oxygen from seawater.

The sapsucking slugs are a group of sea slugs that retain and utilize chloroplasts from their algal food to produce energy. The Lettuce Nudibranch, Elysia crispata, a sapsucking slug, breathes through ruffled extensions of its body. These extensions resemble the edges of kale leaves, hence the name Lettuce Nudibranch. I should point out, that this slug is not a nudibranch, like its common name would suggest. It is a sacoglossan sea slug. Common names can be misleading with regards to classification. This is why scientific names are designated.

As you can see from the photos, sea slug gills are quite elaborate. As a side note, if you ever want to dress up as a dorid nudibranch, I suggest creating gills by pinning feather-dusters in a plume to your back-end! They look authentic!

Carissa Shipman

Gradute Student

Department of Invertebrate Zoology and Geology

What are sea slugs? Well, they are slugs that inhabit the ocean. Like land slugs, they are covered in slime and they crawl around on their foot. They leave slime trails, just like land slugs do. It was pointed out to me that the slime trails left by land slugs can act as a prism when hit by sunlight. This causes their trails to emit a beautiful spectrum of color.

Sea slugs unlike land slugs have adapted to the ocean in a variety of ways. Nudibranchs, a group of sea slugs, are known for their bright colors and ostentatious ornamentation. Their bright colors and diversity in shapes and forms have a purpose. What makes them so attractive and oftentimes strange is their frilly rhinophores and gills. What are rhinophores? They are horn-like structures which protrude from the front of the sea slug. “Rhino” means nose and “phore” means carrier. They are given this name since they give the sea slug their sense of smell. Our noses are capable of picking up chemical signals from the air. Rhinophores are able to pick up chemical signals in the water.

These rhinophores come in a variety of shapes, colors, and sizes. They have been organized into categories based on their shape. Some of these categories are smooth, rolled, sail-like, branched, so on and so forth. Many rhinophores are very elaborate. These more advanced and intricate rhinophores increase the surface area of the organ, which enhances detection of chemicals in the water.

Rhinophores are very important for the survival of most sea slugs, however, there are some sea slugs, which lack them. These slugs have other structures, which aid in their sense of smell. Rhinophores allow sea slugs to find their food and other slugs to mate with, avoid predators, and even sense changes in water pressure and vibrations. Different nerves within the rhinophores send information to the brain. Dendritic nerve cells pickup chemicals and ciliated nerve cells aid in sensing vibrations or changes in water pressure.

Finally, rhinophores help us classify and identify species of sea slugs. Below are some gorgeous Macro images of some rhinophores from California nudibranchs taken by marine biologist Gary McDonald. Enjoy!

Annulate rhinophores of the sea slug Flabellina trilineata

Lamellate rhinophore of the sea slug Cadlina modesta

Smooth rhinophore of the sea slug Doto amyra

Perfoliate rhinophores of the sea slug Flabellina iodinea

Carissa Shipman

Gradute Student

Department of Invertebrate Zoology and Geology

From Madang, Papua New Guinea…

While the phyllidiids are the most common nudibranchs here, there are several other species that we encounter regularly.  But first, a little background…  For a review on the very basics of sea slugs and nudibranchs check out this older post.

Generally, nudibranchs are subdivided into 4 groups:

1. the dorids

2. the dendronotids

3. the arminids

4. the aeolids- these animals have a branched digestive system that passes through appendages on their backs called cerata.  The cerata also function as gills, and in many species they store stinging cells from the aeolid’s prey (such as corals, anemones and hydroids) that can be used for their own defense against prededators.

Here are some photos of three of the most common aeolids we’ve seen in Madang:

From the field…

One of the goals of this expedition is to document all the species of mollusks and other invertebrates that live in the Madang Lagoon.   Everyday a group of us “hunter-gatherers” goes out to look for species that we haven’t encountered yet.

When you are looking for animals, you are likely to find several that are pretty common, and you have to work a bit harder to find the other species.   There are several species that have been “common as muck” on this expedition. For nudibranchs, the most common we’ve seen are the phyllidiids, which in general are the most common nudibranchs on Pacific coral reefs.

You can see phyllidiids on just about every dive.   There are several different species and many are rather difficult to tell apart.  They are all rather tough-bodied and because they secrete some nasty toxins, you can’t keep them in a dish with other nudibranchs.   If you disturb them, you can actually see them secrete the white, milky toxins.  After touching phyllidiids you can even smell the toxins on your fingers.  Trust me, it’s not the most pleasant smell…

Note from the photos that phyllidiids do not have a typical gill on their backs like many other dorid nudibranchs.  Instead, they have respiratory structures on the sides of their bodies underneath the mantle.

Stay tuned for more notes from the field…

Vanessa Knutson

Project Lab Coordinator

Graduate Student

Invertebrate Zoology and Geology

Imagine exploring a new place and seeing a type of animal you’ve never seen before. Something that appears to have feathers like a bird, but is much faster and smaller than any bird you’ve seen before. Perhaps it’s a new species of animal – part insect and part bird!

This is what European settlers encountered when they first explored the New World and saw hummingbirds. You may not have previously known it, but hummingbirds don’t exist in the Old World (Europe, Asia, and Africa). They’re so commonly seen on a walk through Golden Gate Park that you might not realize what a special treat they are for some international visitors!

Photo courtesy of Laura Wilkinson

I recently prepared the most commonly seen hummingbird in this area: the Anna’s hummingbird. They are a larger species and have beautiful coloration (as do all hummingbirds, admittedly). Adult male hummingbirds have brightly colored feathers on their throats, and sometimes covering their heads, called a gorget. The gorget of the Anna’s hummingbird is a bright magenta color when it catches the light just right.

Photo courtesy of Laura Wilkinson

My last visit to the Project Lab blogosphere found me straying from my doctoral dissertation research in order to identify and describe a group of Australian beetles, which were new to science. Today, however…I return to my true passion: Snail Eating Beetles!

Scaphinotus interruptus. Photo courtesy of Joyce Gross.

Now you might fall into the category of folks who find beetles and other bugs creepy or even frightening but fear not, unless of course you are a snail! Harmless to humans, these relatively large beetles come out at night to hunt for native snails and slugs, which they approach and devour live.

Scaphinotus angusticollis. Photo courtesy of ©2008 Walter Siegmund.

Snail-eating beetles belonging to the genus Scaphinotus can be found across North America, including 15 species right here in California.  Scaphinotus has evolved a unique body shape or morphology, which aids them in feeding on snails. They have elongate heads and well developed mouthparts, as well as long legs. This means they can stick their heads up into the shell to reach the snail, while standing far enough away from the snail to prevent the mucus from sticking to their bodies. In this way, they are able to take advantage of a food resource that many other insects cannot.

Scaphinotus hatchi. Photo courtesy of Meghan Culpepper.

So aside from being veracious feeders what makes Scaphinotus so interesting? I am interested in understanding how the species of Scaphinotus are related to one another, where their ancestors may have lived many millions of years ago, and what factors might have led to their speciation.  The Entomology Department and Project Lab here at California Academy of Sciences have proved integral to my studies and to the studies of many other scientists from across the world.

Want to find Snail-eaters in your own back yard? Grab a headlamp or flashlight and head outdoors after the sun has set.  You may find Scaphinotus on their nightly prowl for snails and slugs. If you prefer the daylight hours for your beetle hunting try lifting rocks and logs, a popular hiding spot for many nocturnal insects!

Meghan Culpepper

PhD Candidate

Entomology Department

In my last blog post, I mentioned that I was heading to Papua New Guinea for an expedition to the Madang region.  I decided that on my way to Papua New Guinea, I would make a stop in Australia to do some sea slug collecting.  I was particularly interested in collecting specimens in the Sunshine Coast region of Queensland, Australia, because of a fantastic website that documents the sea slugs found there (www.nudibranch.com.au).  What interested me most is that this site has photos of species in the region that are new to science and belong to the group that I study.

In order to collect in Australia (or anywhere, for that matter) permits are essential. The folks from the Queensland Museum have been extremely helpful with organizing permits for me. This could not have worked without their help and kindness. Special thanks to Dr. John Healy and Dr. John Hooper.

I ended up going to two beaches to do some intertidal collecting- Kings Beach and Shelly Beach.  Check out some of the opisthobranchs (sea slugs) I found:

This last image belongs to a species that is a new record for nudibranch.com.au.  I met Gary Cobb, the site maintainer and he was very excited that I found this species. Pretty exciting!

Stay tuned for more about my trip…

Vanessa Knutson

Project Lab Coordinator

Graduate Student

Invertebrate Zoology and Geology

In my last blog I discussed the Xerces Blue butterfly, a California native with the distinction of being the first known insect species to go extinct in North America as a result of man’s activities.  This week I will pay tribute to two more butterflies that appear to have joined the ranks of animals that have disappeared from the face of the earth.

The first is the Unsilvered Fritillary, Speyeria adiaste atossa, a former common resident of Southern California, once found in the Tehachapi, Tejon and San Jacinto mountain ranges, last observed and collected around 1960.   In this case, the cause of extinction is not entirely clear, and may not have been a direct result of the activity of man.  These butterflies are found near the tops of mountains, and loss of habitat due to development is not a likely cause. This species and its related subspecies feed on wild violets, which do not seem to be in decline. Some workers think that massive droughts in the mountains in the late 50’s may have weakened the population and made them susceptible to disease. Two more northern subspecies found in the Santa Cruz and Santa Lucia Mountains (Speyeria adiaste adiaste and Speyeria adiaste clemencei) also appear to be in rapid decline, but they have not yet been listed as endangered.

While the subject of my last blog, the Xerces Blue, was the first North American species to be officially listed as extinct by the U.S. Government, it appears that it was beaten out by an earlier extinction, that of Boisduval’s Satyr (Cercyonis sthenele sthenele). There is little mystery as to why this butterfly disappeared from San Francisco in the 1870’s… it was forced out by loss of its hilltop grassy habitats as the city rapidly expanded after the gold rush.

Prior to the 1906 earthquake, California Academy of Sciences had a good collection of specimens of this species, which were lost in the fire that followed the quake. The specimen shown is the only one now in our collection, with other specimens found in our National Museum in Washington D.C.  This specimen was collected around 1855 by Pierre Lorquin, an amature butterfly enthusiast who came to California for the Gold Rush. He sent specimens to Dr. Boisduval in Paris, who named the species. Years later, the entire Boisduval collection was purchased by Dr. Barnes, an American lepidopterist who donated this specimen to the Academy.

Next time I will explore more endangered/extinct California Insects.

Vic Smith, Imaging Specialist and Curatorial Assistant

From the field in Madang, Papua New Guinea…

Expeditions are far from being all fun and games.  One of the more frustrating aspects for me is traveling with so much BAGGAGE.   I love traveling, but when I travel for personal vacation, I generally like to only take a backpack and carry-on.   The trouble with an expedition, and particularly one that involves SCUBA diving, is that you have to take a lot of gear with you.  This is especially challenging if you have to mind all of your gear by yourself.

While the issue of carrying all that baggage and keeping an eye on it is trouble enough, these days there is another major issue involved: excess baggage fees.   You may have experienced this yourself during your own travels and know how frustrating it can be.  So far, I’ve been slammed with excess baggage fees for nearly each leg of my trip! Hopefully, I’ll use up enough of the sunscreen I brought with me to save a few bucks on the way back. ; )

Okay, enough with the venting about excess baggage fees! What kind items are so essential that I’m getting slammed with fees?  It’s certainly not clothes.  I looked up the temperature before I left and the weather in Madang is supposed to be about 86°F, both night and day, so I’m not toting around heavy outerwear or anything like that.  Other than the sunscreen I already mentioned, the main culprit is SCUBA gear and safety equipment.  I have fins, a buoyancy compensator, regulator, wetsuit, and everything I need to dive except for a tank and weights (good thing I don’t have to lug that around with me!).  I’m even carrying an Automated Electronic Defibrillator  (AED) in case of an emergency in the field.  That thing and its case weigh more than a bowling ball, but hey, I guess better safe than sorry.

Stay tuned for more of my adventures…

Vanessa Knutson

Project Lab Coordinator

Graduate Student

Invertebrate Zoology and Geology

While this time of year is full of stories of ghosts, spirits and trickery, sometimes we don’t have to look far to see a frightening story happening right in our midst!  The story of the San Joaquin Kit fox is one of a disappearing species in danger of extinction.

Kit foxes (Vulpes macrotis) are small mammals in the Canidae family.  Most of us know what a grey fox or red fox looks like and sometimes have seen them in Golden Gate Park quietly running through the trees.  Kit foxes aren’t seen around the Bay Area unfortunately, as Kit foxes prefer a little bit less drizzle and a little more desert.  Their habitat ranges in the southwest USA and down into central Mexico.  These charismatic species are about the size of a house cat with huge ears for hunting in the evening.

One of the larger species of Kit Fox, the San Joaquin Kit Fox can only be found in California’s Central Valley.  Once lush grassland, in the early 1900s agriculture came to the Central Valley and farmers readily converted fertile soil into bountiful cropland.  Warm temperatures and readily available water from the San Joaquin River seemed perfect for settling down.  With most of the land being used for farming or raising animals for consumption, the San Joaquin Kit fox was pushed out of their native habitat into the fringes of the San Joaquin Valley, clinging to survival with less than 10,000 individuals.

In March of 1967, the San Joaquin Kit fox was listed as an Endangered Species under the Endangered Species Act and has stayed there ever since.  Current riparian habitat restoration along the San Joaquin River has seen some success with sightings in 2006 and 2008 of the Least Bell’s Vireo (Vireo bellii pusillus) bird, another native species that has been extirpated since the 1950s.  Successful restoration projects are helping many birds and mammals make their way back to their native habitats and hopefully keep them from falling into history as a species that once was.

Hearing stories about species like the San Joaquin Kit Fox and thinking about current day extinctions are scary enough for me to last long past the end of October!  This male San Joaquin kit fox was hit by a car in Kern County all the way back in 1997 and will finally make its way into the Academy’s pelt collection, skeleton collection and tissue bank.  Researchers will be able to look at our few specimens of Kit Foxes and study their genetics and population distribution to see how to potentially help these small foxes.  Striking the balance between farmland that provides food for humans but that also can provide habitat for many different species is a complicated process.  With a lot of work and dedication by many individuals the San Joaquin Kit Fox can become a success story instead of a tale of ghosts…

Codie Otte
Curatorial Assistant and Specimen Preparator
Ornithology & Mammalogy Department