[ Music ] ^M00:00:07 >> [Background Music] Hello students. This is Plants and Animals in Southern California. And today, we're not in the field but we are as we're standing in Chaparral Hall in the first floor in between the two big lecture halls and we're looking at this cabinet full of shells. And today, I have with me Lorraine Smith [assumed spelling] who put together the cabinet and she's going to tell us about the shells that are--So, welcome to Plants and Animals. >> Hello class. Thank you, Paul. >> So, this is all about mollusks. So let's start out with what is a mollusk and then later on we'll end up with what is not. >> OK. So, mollusks they include some of the best known invertebrates. They make up a large group of organisms that generally share a certain characteristics, such as a muscular foot for movement, mantle surrounding the organism. They usually have a hard shell secreted by that mantle and then sometimes a gill or two for obtaining oxygen from the water. >> So you have here things like snails and mussels and oysters and clams? >> Yes. >> Those are all mollusk and abalone? >> Yes. >> And then--Then there's some other groups of mussels, so maybe we should go through just the major classes. >> So--Yes. So there are several major classes of mollusks. The major classes include the polyplacophora which that group or-- >> Chitons. >> --the chitons are in that group, yes. The gastropods that we know, the limpet's thing--include the limpets, abalones, snails and slugs. The next group would be the Bivalvia. This--The bivalves include clams, mussels, oysters and scallops. Delicious. And then the cephalopods, so octopus, squid, cuttlefish and nautilus. >> The classic calamari. >> Yes. So there are seven classes of mollusks but this display actually focuses primarily on two, the Gastropoda and Bivalvia. And this is mainly--this is because mainly all--well, most species within these groups have a shell and the shells are preserved well and are very nice to display. >> Let's talk about living in soft-sediment. So, these are things like clams. >> Everything on display for living in soft-sediments are bivalves, just want to give you a little bit of background on that taxonomic class if that's OK. >> Yeah. >> So, clams, oysters, mussels and the like include Bivalvia. And their group comprises of approximately 15,000 species. >> 15,000? >> They are laterally compressed typically with a shell that contains a right and left valve that hinged together dorsally by ligaments. So the--And the shells are closed by adductor muscles. So they have a large mantle cavity and the posterior edges of the mantle cavity are often used to form siphons in the incurrent and excurrent siphon. >> OK so, water along with little food particles and stuff comes in the incurrent siphon. I think that's usually bigger. >> Yes. >> And then it's somehow processed and the food particles are taken out and-- >> Yes. >> --things are maybe added. And then the water and whatever is going out goes out the excurrent siphon which is usually a little bit smaller in diameter, right? There's some hydrodynamic reason for that, right? >> Yes. And so, yeah, their habitat can be infaunal so living inside the sediment. They actually, you know, with their muscular foot burrow down into soft sediment. They can be epifaunal, so very, very close to this surface, but still under sediment. Or epifaunal, so on top of the sediment and then there are also boring bivalves that-- >> Much harder. >> Yes, that bore into wood or-- >> Substrates. >> Yes, rock type substrates. >> And then let's go to some--through some of the names of these. >> Yes. >> So, like you feature this one Clinocardium Nuttallii. >> So, this one we have kind of displayed in the middle here. It's nice large specimen. This is--The common name is the Nuttall cockles. It's a, you know, a cockle. >> Cockle, yeah. >> Commonly known. >> There's a song about that. >> Yeah. >> And Nuttall was an explorer. Often if an explorer will collect a species that's new to science, and then send it off to an expert, and sometimes the expert will name it after the explorer and usually that's designated with--if the explorer was a man, an "ii" at the end. >> Interesting. So this species inhabits from sediment and the strong concentric ridges together with the thick shell provides these clams with [inaudible]-- >> You mean like compacted mud. >> Yes. >> OK. Well, as opposed to sand. >> Yes. >> OK. And then what about--are those razor clams? The little-- >> Yes. >> --or something like the-- >> Yes, the Tagelus californianus. And their shell is, you know, much thinner so they're [Background Music] in sand or softer sediments. ^M00:05:46 [ Music ] ^M00:05:48 >> [Singing] In Dublin's fair city, where the girls are so pretty, I first set my eyes on sweet Molly Malone. As she wheeled her wheel-barrow through streets broad and narrow, crying cockles and mussels, alive, alive-O! Alive, alive-O! Alive, alive-O! Cockles and mussels, alive, alive-O! >> Do you want to go on to hunters-- >> Shall we move on? >> --and scavengers? >> Sure. >> All right, so--and you've got the--you've got some of them on top of a cutout worm here. >> Yes. So the hunters and scavengers. So, several of the species they have this--they have a siphon and what it actually--it's part of the mantle cavity. So they have the mantle on the left side of their body is rolled up into a tube that makes kind of an incurrent snorkel. And then they usually have a protrusible proboscis with radula and mouth, so teeth and mouth at the tip and that they're predators, scavengers. So, just to kind of put this into this category the group that most of the shells we have on display are in the taxonomic group Neogastropoda and they all have this siphon. So, I wanted to pointed that-- >> Neogastropoda. >> The neo or new gastropods. >> So for instance these cones--cone snails, conus-- >> The conus Californicus. >> Conus Californicus. >> Yes, yes. >> Yeah, those are related to the ones that are poisonous that-- >> They are. >> --have little darts that if you touch you like might die. >> Those are more Indo-Pacific. >> These ones have--still have darts but-- >> They do. But the-- >> --people are not-- >> --the toxins-- >> --they're not as dangerous? >> Right. The toxins are, you know, just not very strong. So cone snails use their--that barbed hypodermic glandular tooth to immobilize their prey like a worm or something smaller. But they immobilize their prey by injecting paralyzing toxins into their victim and then eat them. >> OK. And are we done with the cone snail? >> Yes. >> OK. So can you say the name of one of these? >> Yes, Megacircula and the species is Carpenteriana. >> Carpenteriana. When you have that Ana on the end that usually means it was named after somebody named carpenter. But in this case--but it wasn't the discoverer of it. It was just because Carpenter was such a great guy. OK. So I guess we're time to move--it's time move on. >> Yes. >> So let's see. We have some snails here with great big ridges on their shells and they're on a cutout of an urchin. >> Yes. We have our bursa californica. This is California frog snail. And these really cool gastropods actually hunt on a very specific prey item, sea urchins. So they attack the urchin's vulnerable soft tissue that surrounds the mouth on the underside. And then once that they pass that fleshy barrier the snail inserts that siphon and consumes its delicious soft organs. >> Sushi. All right, OK, bursa californica. >> That's--yup. >> And there's another one behind it. Bulla. >> Bulla. >> Bulla. >> Bulla gouldiana. So that's the-- >> So it was named after Gould but Gould didn't discover it. >> OK. And yeah, this is the bubble snail and this is actually related to snails and slugs. >> Like a sea hair or something? >> Yes. >> OK and that is like an order-- ^M00:09:57 >> Opisthobranch. It is an opisthobranch. So, its shell, even though looking at it in the display it looks like a regular calcified shell. It's actually calcareous. It's very thin. And so that's one of the characteristics in that group with the other slugs. They have either a reduced or completely lost shell. So this is a good example for that. This bubble snail is a grazer so they basically sweep across the surface of sediments and they eat nutrient rich algae. >> OK. So right above that you have a little photo and there's a whole bunch of these horn snails together. What are they doing? >> They're--This is a picture of an aggregation of the California horn snails, Cerithidea californica. And they will gather in muddy intertidal areas to feed on detritus and other delicious things on the surface of mud. >> So they just like the mud and then they get rid of the sand grain--the grains and mineral. They're the gooey. >> Yeah, they love it. >> All right, cool. All right. So moving right along here. >> Right along. So I also have a nice picture in the display of one of those slugs that is a predator Navanax inermis. >> And that's also an opisthobranch? >> It is. Yes. So it has a--its shell is I guess you could say reduce to the point of being lost. There is a-- >> Not noticeable. >> Not noticeable, yes. But it's predatory. It attracts its prey by following mucus trails of other-- >> And opisthobranchs do all sort of stuff. Some are grazers and some are predators and scavengers. >> Yes, yes. >> OK, now there's a whole bunch of little shells here on top of the cutout of a bivalve and then one of them is Pteropurpura, right? Ptero means wing. >> Yes. >> And these must be like little winged-- >> Murex, yeah. Yeah, they're the wrinkle-wing Murex. So these are predatory. These four different species I have on this cutout are predatory gastropods on bivalves. >> And it's--so it's Pteropurpura vokesae, V-O-K-E-S, right? >> Yeah. >> And then it's A-E which is honorary for a woman. >> Really? I didn't know that. >> Where as the nautilii, that's honorary for a man. Maybe somebody discovered it whose name is V-O-K-E-S maybe a [inaudible]. >> Interesting. >> Or maybe just V-O-K-E-S. Vokes. Well, we have to figure out who she was. >> Yeah. And we also have the spotted unicorn which is just above this-- >> The unicorn? >> Um-hmm. >> OK, this is--well, how do you say it? >> The Acanthinucella punctulata. >> Punctulata. Acanthinucella. Yeah. I only can pronounce it because I already know the word Nucella, so you if you put [inaudible] in front of it so it's not too hard. >> It's not too bad, yeah. And then-- >> Yeah, so it's very [inaudible]. >> Yeah, so spotted unicorn and then just next to that, brightly orange colored Nucella ostrina that--they're not all this color. These species has a lot of different color ones. >> Right. I know a lot of ones that are just sort of a-- >> Kind of plain. >> Round. >> Yeah. >> A little bit of wide [inaudible]. >> But this one is flashy, so it made the display. ^M00:13:45 [ Inaudible Remark ] ^M00:13:46 Yes, they're very charismatic. I love Nucella. OK. And on the scavengers. >> OK. So like a fish dies in the ocean and somebody notices. >> Yes, and you'll-- >> Maybe these olives. >> You'll find several different species of gastropods that will take advantage of a decaying body for sure. Yes, all of snails, Callianax biplicata. >> Callianax. >> Callianax. >> Kind of rolls off the tongue. Callia I think means beautiful. They are kind of beautiful. >> They are very shiny. And then the Kellet's whelk, so Kellatia kelletii--kelletti or kelletti--kelletti. Yes. There's a really nice display at Cabrillo that has these. >> San Pedro. Yes, so Cabrillo is this little aquarium but it's like super good for educational purposes. >> Yes. >> Way better than the aquarium in Pacific, because each little display explains things really nicely. >> Yes. And I've really kind of emulated this entire display based on several of their displays at Cabrillo so that's-- >> Yeah, great place to go. >> Great place to go. They have a really cool display that's just has these Kellet's whelks that are up on the platform and you can see how long their siphon is. It reaches down. They have a dead fish down at the bottom of the tank and you know, will reach down about a foot down and then it, you know, it has that protrusible proboscis. >> So it's not like elephant's proboscis. >> No. >> Like an elephant's proboscis can-- >> It can't grab. >> --is at the tip of its nose. >> Right. >> But it still has its mouth some place else. >> Its mouth is actually--so it's siphon and then it has a proboscis with teeth and its mouth at the end. >> Grind, grind. >> Yes, eating delicious rotting fish. So--And there are a few others here. >> OK. So we've got some sort of miscellaneous out here. Is that your general list? >> There's some just generalist hunters so that many gastropods are [inaudible] spheres. >> Is that a keyhole limpet? >> It is a keyhole limpet. Yeah, so a lot of them feed on seaweeds, microorganisms, hydroids, sea anemone, rhizomes. >> That's a cowry next to it, I think. >> There's a beautifully cowry and it's shiny and I didn't, you know, put any kind of a glazing or anything on the shell. They're actually shiny like this because the mantle actually warps around the entire shell and so it keeps it very shinny and smooth. And shall we move on to shell drilling? >> Oh, yeah, shell drilling. So here are some shells that have holes in them like there are some Norrisia there. And you can see it's got--they've got holes on them. So you're not--these are the guys who should drill the holes, these are prey. >> These are--yes. >> That got sucked. >> Right. So these were sadly--yes. >> Sadly for them. >> Yeah. >> Nothing is evil in the universe. >> Right. So the rasping action, the teeth on the gastropods radula and then combined with the release of the softening agent from the mouth where is this really characteristic countersunk hole. You can kind of see that. >> It's like a hole in a hole. >> And the shells of these various preys such as I guess I do have one little bivalve and then different snails. And then once a hole is drilled, the gastropod inserts its siphon into the hole again eating [Background Music]--thank you Paul--eating these soft tissues. >> [Singing] She was a fish-monger, but sure 'twas no wonder, for so were her father and mother before. And they each wheeled their barrow, through streets broad and narrow, crying cockles and mussels, alive, alive-O! Alive, alive-O! Alive, alive-O! Crying cockles and mussels, alive, alive-O! >> So moving on, filter feeders. Now, way back at the beginning we were talking about these clams that dig themselves into the mud and so on, they're filter features as well. But let's pick up with a few other filter feeders. So there's a diagram here, mussel, and the mussel is tied to the rock by byssal threads. >> Yes. >> And it how's that worked like they have super glue or what goes on? >> The byssal threads themselves attach to hard substriate. >> And they make new ones all the time or-- >> They do. They make new ones. And depending on their environment-- >> What makes it? It's not the same as what makes the shell. >> No, there's--they have a byssal gland that secretes this very like proteinaceous material. It's like almost like a thread, and the thickness, you know, there's plasticity with the thickness. So depending on the environment, if there's a lot of wave action, the byssal threads can be thicker than an environment that's, you know, kind of calm. And you usually see aggregations of mussels and that's another-- >> Nautilus-- >> Nautilus. >> Nautilus california. >> And then this is where I have the on display, that really beautiful scallop. This is the San Diego scallop. >> Pecten diegensis. Yeah, and that ensis business at the end, that usually means it's from some place like from San Diego, Pecten diegensis. >> That makes sense. And what's interesting with these scallops, they--so you can really see how asymmetrical they are, the one valve is flattened where the other valve is more concave. And these bivalves are--they can actually swim which is [inaudible]. ^M00:20:00 >> Yeah, they would just pump water between their shells. >> Yes. >> And that makes them jet out. >> Yes, and unlike-- >> They jet across the bottom of the ocean. >> They do. And unlike the nautilus that where nautilus have two adductor muscles, the scallops only have one adductor muscle in the center and it's very large. And that's-- >> That's the yummy thing. >> Right. >> But the ones that we eat are much bigger than this, right? >> Yes, those are giant scallops, yeah. >> OK. And then there's something that looks like an oyster but it's not. >> It's not. It's related to the oyster but it is not an oyster, Pseudochama. >> Exogyra maybe. >> Yeah, I think so. >> Pseudochama exogyra. And oysters would normally live in muddy places. But these I think kind of glue themselves to rock. Yeah. >> Yeah, this--I actually found this shell in Abalone--near the Abalone cove. >> OK. >> Yeah. >> And its common name is jewel box. >> Oh, yeah, it's like a little box, like one side of the bivalve is much smaller than the other, so it looks like a lid on a box. >> Yes. >> OK. And then the next thing is all these things that are on top of a cutout of a kelp. And I guess this is to indicate the various animals that graze on one kind of algae or another, not necessarily kelp. Some of them would just graze on a turf-- >> Yes. >> --turf or something like that. >> Yes. Yeah, so all of these mollusks can be found along the intertidal rocky shore feeding on various kinds of sea [inaudible]-- >> But let's see. Acmaea mitra, I think that actually is a specialist on quite big pieces of kelp, or, you know, great, big round. >> Where you'll find it attached to the kelp, yes. >> And usually if they're alive I don't think they're white like that. >> No. Yeah. So gastropods use their radular teeth to scrape algae off of hard substrates or to eat the blades of the algae. And the radular works like a file as a ribbon of teeth that scrapes algae and the plant material off of hard surfaces. >> You got a little picture here of it. >> I do. So this is just one type of--there's the--the radular teeth morphology is highly diverse and dependent on-- >> The taxonomist actually used it to like sort out the [inaudible] and so on. >> Yes. And herbivorous gastropods have more teeth per row than say a predatory gastropod. So that's one indicator. But then within that, then not just the number but the morphology of the teeth as sort of-- >> And we find these ones a lot. What are these? >> That is-- >> These little gray ones that are turbinate like that? >> Yeah, Chlorostoma funebralis which used to be Tegula fenubralis but that's the--this is black turban snail. It's a common name, yeah, so Chlorostoma funebralis is the new name. >> I mean you have quite a few limpets here like there's a volcano limpet and then there's a Collisella scabra. It's kind of like rough around the edges. >> Yes. We have a couple of different Lottia species that we have an owl limpet, the Lottia gigantea. >> So there are several species of abalone. I guess, the red ones are the ones that are the most common but even they have suffered some declines. >> Yes. And they are farming a lot of abalone which is helping as far as the fishery is concerned. It's not-- >> Yeah, so you can get farmed abalone and--and you got--actually, you've got some other species here like--is that a black abalone? >> A black abalone and then a corrugated abalone that's kind of has more of a wavy morphology to its shell. >> So, the final kind of ecological trophic combination are the boring clams. >> Yes. >> And these aren't like totally boring. They're actually super interesting. So the example we have here are piddock clams. >> So piddock clams cause coastal erosion through the process of boring into subtitle and sedentary rocks. And actually, they erode away an estimated 3 to 10 millimeters of rock per year in the mid-intertidal and subtidal range. And then-- >> And when a little piddock clam lands on the rock, settles on the rock, then it starts grinding and it has this whole like rasp on one side of its shell. And then it grinds into the rock and then it keeps on growing of course too. >> Yes. >> Right? So the holes come out looking like inverted funnels. >> They do. Yeah the cone shaped wall is due to the constant rotation of the clam during boring, yeah. And these piddock clams you can see the kind of the gape at the top here, that's where the shell valves gapes widely at the interior end where the muscular foot extends out and it grips the burrow wall. Then like you said, those spines or ridges or teeth are along the side of the valve. >> And these are also filter feeders? >> Yes, so they extend their siphons out. Yeah, those ridges are well developed on the outer surface of the valves and that functions in enlarging the wall. >> OK. Well that's the gastropods, bivalves and I don't know. Maybe there's a chiton in there, and they all belong to the mollusca. >> Yes. >> And then--so then there're a few things here that kind of has shells that you might mistake for a mollusk shell but they are not mollusks, so let's go over those. >> Yes, so-- >> OK. So here are some barnacles. And-- >> So barnacle-- >> Barnacles are what? >> They're actually in the phylum Arthropoda and they are-- >> Sort of like a lobster. >> Sort of. They are cirripedia so they have these just in a different taxonomic group. But the animal itself were arthropod, cements itself anteriorly, basically cements its head to the substrate and has this long cirri--hence cirripian, the cirripedia. >> And they filter feed too. >> --extend out--that filter feed, yes. And then-- >> And like even compete with like a mussel. >> Yes, they can. >> Maybe not this species, but some others. >> Right. So they attach and then there are six calcareous plates that are attached and they are similar compositions of some mollusks but they're not. >> And then the next thing, these are the external shells of things like feather dusters? >> Yes, so two worms, so polychaete tubes hair that are calcareous, very similar to shells and mollusks. >> OK. Well, thanks a lot Lorraine. >> You're welcome. >> And I guess we should thank a few other people like-- >> Yes, absolutely. >> Somebody paid for this. I'm not quite sure if you--but it's probably the students. >> And Cabrillo Aquarium and Dr. Michael Franklin for donating many of the shells that are displayed here. >> All right, so Lorraine Smith there, you have it. [Background Music] Plants and Animals in Southern California, tune in next time for something on something else. Bye >> [Singing] --barrow through streets broad and narrow, crying cockles and mussels, alive, alive-O! >> So the music that I've spliced in here is by the Celtic Angels. >> [Singing] Alive, alive-O! Alive, alive-O! Crying cockles and mussels, alive, alive-O! Alive, alive-O! Alive, alive-O! Crying cockles and mussels, alive, alive-O!