Tag Archives: mollusks

Friday Fellow: Sea Swallow

by Piter Kehoma Boll

As the second species of today, I’m bringing a terrible but beautiful predator of the Portuguese man o’ war, the sea swallow Glaucus atlanticus, which is, in my opinion, one of the most beautiful sea creatures.

Glaucus_atlanticus

Isn’t it a magnificent creature? Photo by Sylke Rohrlach.*

Also known as blue dragon, blue glaucus and many other names, the sea swallow is a small sea slug that measures up to 3 cm in length as an adult. This species is pelagic, meaning that it lives in the open ocean, neither close to the bottom nor close to the shore.  Although it is found in all three oceans, genetic evidences indicate that the populations from the Atlantic, the Pacific and the Indian oceans have diverged more than 1 million years ago.

The sea swallow has a gas-filled sac in the stomach that makes it float upside down in the water, meaning that its ventral side is directed upward. The wide blue-bordered band running along the body, as seen in the picture above, is the slug’s foot. It’s dorsal side, which is directed downward, is completely white or light gray.

Being a carnivorous species, the sea swallows feeds on several cnidarian species, especially the Portuguese man o’ war. It usually collects the cnidocytes (the sting cells) of its prey and put them on its own body, so that it becomes as stingy as or even stingier than its prey. If you find one lying on the beach, be careful.

– – –

References:

Churchull, C. K. C.; Valdés, Á.; Foighil, D. Ó (2014) Afro-Eurasia and the Americas present barriers to gene flow for the cosmopolitan neustonic nudibranch Glaucus atlanticus. Marine Biology, 161(4): 899-910.

Wikipedia. Glaucus atlanticus. Available at < https://en.wikipedia.org/wiki/Glaucus_atlanticus >. Access on June 18, 2017.

– – –

*Creative Commons License
This work is licensed under a Creative Commons Attribution-Share Alike 2.0 Generic License.

Advertisements

Leave a comment

Filed under Friday Fellow, mollusks, Zoology

Friday Fellow: Hummingbird Bobtail Squid

by Piter Kehoma Boll

If you are digging through the sand at the bottom of the clear tropical waters around Indonesia and the Philippines, you may end up finding a colorful little creature, the hummingbird bobtail squid, Euprymna berryi, also known as Berry’s bobtail squid.

Euprymna_berryi

A beautiful specimen photographed in East Timor. Photo by Nick Hobgood.*

Measuring about 3 cm if male or 5 cm if female, the humminbird bobtail squid is actually more closely related to cuttlefish than to true squids. Its body has a translucent skin marked by many black chromatophores, and to the human eye the animal seems to have a color pattern formed by a blend of black, electric blue and green or purple dots.

During the day, the hummingbid bobtail squid remains most of the time buried in the sand, coming out at night to capture small crustaceans, which it hunts using a bioluminescent organ in its gill cavity.

In some areas around its distribution, the hummingbid bobtail squid is captured and sold in small fisheries, but as the data on the distribution and population dynamics of this species are very poorly known, there is no way to say whether it is vulnerable or endangered in any way. As a result, it is listed as Data Deficient in the IUCN Red List.

– – –

ResearchBlogging.orgReferences:

Barratt, I., & Allcock, L. (2012). Euprymna berryi The IUCN Red List of Threatened Species DOI: 10.2305/IUCN.UK.2012-1.RLTS.T162599A925343.en

Wikipedia. Euprymna berryi. Available at <https://en.wikipedia.org/wiki/Euprymna_berryi&gt;. Access on March 8, 2017.

– – –

*Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

Leave a comment

Filed under Friday Fellow, mollusks, Zoology

The history of Systematics: Animals in Systema Naturae, 1758 (part 4)

by Piter Kehoma Boll

This is the fourth and last part of this series of posts. See here part 1, part 2 and part 3.

I’m presenting here the 6 th and last class of animals: Vermes. It included basically anything that was neither a vertebrate nor an arthropod.

6. Vermes (worms)

Heart with one ventricle and one auricle; cold pus.
Spiracles absent?
Jaws multiple, various.
Penises several in hermaphrodites, androgynous.
Senses: tentacles, head absent (rarely with eyes, no ears and nostrils).
Covering: sometimes calcareous or absent, if not spines.
Support: neither feet nor fins.

Vermes were classified according the form of the body in 5 orders: Intestina, Mollusca, Testacea, Lithophyta and Zoophyta.

6.1 Intestina (internal ones or intestines), simple, naked and without appendages: Gordius (horsehair worms), Furia (the legendary worm), Lumbricus (earthworms and lugworms), Ascaris (roundworms and pinworms), Fasciola (liver flukes), Hirudo (leeches), Myxine (hagfishes) and Teredo (shipworms).

Linnaeus’ heterogeneous order Intestina included (from left to right, top to bottom) the water horsehair worm (Gordius aquaticus), the legendary hell’s fury (Furia infernalis), the common earthworm (Lumbricus terrestris), the giant roundworm (Ascaris lumbricoides), the sheep liver fluke (Fasciola hepatica), the European medicinal leech (Hirudo medicinalis), the Atlantic hagfish (Myxine glutinosa), and the naval shipworm (Teredo navalis). Credits to Jiří Duchoň (horsehair worm), Michael Linnenbach (earthworm), Wikimedia user GlebK (leech), Arnstein Rønning (hagfish), Poi Australia [poi-australia.com.au] (shipworm).

Linnaeus’ heterogeneous order Intestina included (from left to right, top to bottom) the water horsehair worm (Gordius aquaticus), the legendary hell’s fury (Furia infernalis), the common earthworm (Lumbricus terrestris), the giant roundworm (Ascaris lumbricoides), the sheep liver fluke (Fasciola hepatica), the European medicinal leech (Hirudo medicinalis), the Atlantic hagfish (Myxine glutinosa), and the naval shipworm (Teredo navalis). Credits to Jiří Duchoň (horsehair worm), Michael Linnenbach (earthworm), Wikimedia user GlebK (leech), Arnstein Rønning (hagfish), Poi Australia [poi-australia.com.au] (shipworm).

 6.2 Mollusca (soft ones), simple, naked and with appendages: Limax (land slugs), Doris (doriid sea slugs), Tethys (tethydid sea slugs), Nereis (polychaetes), Aphrodita (sea mice), Lernaea (anchor worms), Priapus (priapulid worms and anemones), Scyllaea (scyllaeid sea slugs), Holothuria (salps and man o’ wars), Triton (possibly some sort of sea slug), Sepia (octopuses, squids and cuttlefishes), Medusa (jellyfishes), Asterias (starfishes), Echinus (sea urchins and sand dollars).

Among the animals that Linnaeus put under Mollusca are (from left to right, top to bottom) the leopard slug (Limax maximus), the warty dorid (Doris verrucosa), the fringed tethydid (Tethys leporina, now Tethys fimbria), the slender ragworm (Nereis pelagica), the sea mouse (Aphrodita aculeata), the common anchor worm (Lernaea cyprinacea), the cactus worm (Priapus humanus, now Priapulus caudatus), the sargassum nudibranch (Scyllaea pelagica), the Portuguese man o’ war (Holothuria physalis, now Physalia physalis), the common cuttlefish (Sepia officinalis), the moon jellyfish (Medusa aurita, now Aurelia aurita), and the European edible sea urchin (Echinus esculentus).Credits to Marina Jacob (slug), Wikimedia user Seascapeza (dorid), Pino Bucca (tethydid), Alexander Semenov (ragworms), Michael Maggs (sea mouse), glsc.usgs.gov (anchor worm), Shunkina Ksenia (cactus worm), Universidad de Olviedo (sargassum nudibranch), Hans Hillewaert (cuttlefish, jellyfish and starfish), and Bengt Littorin (sea urchin).

Among the animals that Linnaeus put under Mollusca are (from left to right, top to bottom) the leopard slug (Limax maximus), the warty dorid (Doris verrucosa), the fringed tethydid (Tethys leporina, now Tethys fimbria), the slender ragworm (Nereis pelagica), the sea mouse (Aphrodita aculeata), the common anchor worm (Lernaea cyprinacea), the cactus worm (Priapus humanus, now Priapulus caudatus), the sargassum nudibranch (Scyllaea pelagica), the Portuguese man o’ war (Holothuria physalis, now Physalia physalis), the common cuttlefish (Sepia officinalis), the moon jellyfish (Medusa aurita, now Aurelia aurita), the common starfish (Asterias rubens), and the European edible sea urchin (Echinus esculentus). Credits to Marina Jacob (slug), Wikimedia user Seascapeza (dorid), Pino Bucca (tethydid), Alexander Semenov (ragworm), Michael Maggs (sea mouse), glsc.usgs.gov (anchor worm), Shunkina Ksenia (cactus worm), Universidad de Olviedo (sargassum nudibranch), Hans Hillewaert (cuttlefish, jellyfish and starfish), and Bengt Littorin (sea urchin).

6.3 Testacea (covered with a shell), simple, covered by a calcareous shelter: Chiton (chitons), Lepas (barnacles), Pholas (piddocks and angelwings), Myes (soft-shell clams), Solen (razor clams), Tellina (tellins), Cardium (cockles), Donax (wedge shells), Venus (venus clams), Spondylus (thorny oysters), Chama (jewel box shells), Arca (ark clams), Ostrea (true oysters), Anomia (saddle oysters), Mytilus (mussels), Pinna (pen shells), Argonauta (paper nautiluses), Nautilus (nautiluses), Conus (cone snails), Cypraea (cowries), Bulla (bubble shells), Voluta (volutes), Buccinum (true whelks), Strombus (true conchs), Murex (murex snails), Trochus (top snails), Turbo (turban snails), Helix (land snails), Nerita (nerites), Haliotis (abalones), Patella (limpets and brachiopods), Dentalium (tusk shells) and Serpula (serpulid worms and worm snails).

Linnaeus’ diverse order Testacea included (from left to right, top to bottom): the West Indian green chiton (Chiton tuberculatus), the smooth gooseneck barnacle (Lepas anatifera), the common piddock (Pholas dactylus), the sand gaper (Myes arenaria, now Mya arenaria), the sheath razor (Solen vagina), the sunrise tellin (Tellina radiata), the great ribbed cockle (Cardium costatum), the abrupt wedge shell (Donax trunculus), the wary venus (Venus verrucosa), the spiny scallop (Spondylus gaederopus), the lazarus jewel box (Chama lazarus), the Noah’s Ark shell (Arca noae), the European flat oyster (Ostrea edulis), the European jingle shell (Anomia ephippium), the blue mussle (Mytilus edulis), the rough penshell (Pinna rudis), the greater argonaut (Argonauta argo), the chambered nautilus (Nautilus pompilius), the marbled cone (Conus marmoreus), the tiger cowry (Cypraea tigris), the Pacific bubble (Bulla ampulla), the music volute (Voluta musica), the common whelk (Buccinum undatum), the West Indian fighting conch (Strombus pugilis), the caltrop murex (Murex tribulus), maculated top snail (Trochus maculatus), the tapestry turban (Turbo petholatus), the Roman snail (Helix pomatia), the bleeding tooth nerite (Nerita peloronta), Midas ear abalone (Haliotis midae), the Mediterranean limpet (Patella caerulea), the elephant tusk shell (Dentalium elephantinum), the sand worm snail (Serpula arenaria, now Thylacodes arenarius). Credits to James St. John (chiton), Ruben Vera (barnacle), Valter Jacinto (piddock), Oscar Bos [ecomare.nl] (sand gaper), Guido & Philippe Poppe [conchology.be] (razor), femorale.com (tellin, cockle, scallop, ark shell, jingle shell, bubble, fighting conch, nerite, abalone, tusk shell), Hans Hillewaert (wedge shell, venus, nautilus, whelk), Richard Parker (jewel box, marbled cone), Jan Johan ter Poorten (oyster), Wikimedia user Hectonichus (penshell, volute), Bernd Hoffmann (argonaut), Samuel Chow (cowry), Frédéric Ducarme (turban), H. Krisp (Roman snail), Wikimedia user Esculapio (limpet), Matthieu Sontag (worm snail).

Linnaeus’ diverse order Testacea included (from left to right, top to bottom): the West Indian green chiton (Chiton tuberculatus), the smooth gooseneck barnacle (Lepas anatifera), the common piddock (Pholas dactylus), the sand gaper (Myes arenaria, now Mya arenaria), the sheath razor (Solen vagina), the sunrise tellin (Tellina radiata), the great ribbed cockle (Cardium costatum), the abrupt wedge shell (Donax trunculus), the warty venus (Venus verrucosa), the spiny scallop (Spondylus gaederopus), the lazarus jewel box (Chama lazarus), the Noah’s Ark shell (Arca noae), the European flat oyster (Ostrea edulis), the European jingle shell (Anomia ephippium), the blue mussle (Mytilus edulis), the rough penshell (Pinna rudis), the greater argonaut (Argonauta argo), the chambered nautilus (Nautilus pompilius), the marbled cone (Conus marmoreus), the tiger cowry (Cypraea tigris), the Pacific bubble (Bulla ampulla), the music volute (Voluta musica), the common whelk (Buccinum undatum), the West Indian fighting conch (Strombus pugilis), the caltrop murex (Murex tribulus), the maculated top snail (Trochus maculatus), the tapestry turban (Turbo petholatus), the Roman snail (Helix pomatia), the bleeding tooth nerite (Nerita peloronta), Midas ear abalone (Haliotis midae), the Mediterranean limpet (Patella caerulea), the elephant tusk shell (Dentalium elephantinum), the sand worm snail (Serpula arenaria, now Thylacodes arenarius). Credits to James St. John (chiton), Ruben Vera (barnacle), Valter Jacinto (piddock), Oscar Bos [ecomare.nl] (sand gaper), Guido & Philippe Poppe [conchology.be] (razor), femorale.com (tellin, cockle, scallop, ark shell, jingle shell, bubble, fighting conch, nerite, abalone, tusk shell), Hans Hillewaert (wedge shell, venus, nautilus, whelk), Richard Parker (jewel box, marbled cone), Jan Johan ter Poorten (oyster), Wikimedia user Hectonichus (penshell, volute), Bernd Hoffmann (argonaut), Samuel Chow (cowry), Frédéric Ducarme (turban), H. Krisp (Roman snail), Wikimedia user Esculapio (limpet), Matthieu Sontag (worm snail).

6.4 Lithophyta (stone plants), composite, growing on a solid base: Tubipora (organ pipe corals), Millepora (fire corals), Madrepora (stone corals and Acetabularia algae).

Three species listed by Linnaeus under Lithophyta (from left to right): organ pipe coral (Tubipora musica), sea ginger (Millepora alcicornis), zigzag coral (Madrepora oculata). Credits to Aaron Gustafson (pipe coral), Nick Hobgood (sea ginger), NOAA, U.S.’ National Oceanic and Atmospheric Administration (zigzag coral).

Three species listed by Linnaeus under Lithophyta (from left to right): organ pipe coral (Tubipora musica), sea ginger (Millepora alcicornis), zigzag coral (Madrepora oculata). Credits to Aaron Gustafson (pipe coral), Nick Hobgood (sea ginger), NOAA, U.S.’ National Oceanic and Atmospheric Administration (zigzag coral).

6.5 Zoophyta (animal plants), growing like plants, with animated flowers: Isis (bamboo corals), Gorgonia (sea fans), Alcyonum (soft corals), Tubularia (pipe corals), Eschara (bryozoans and red algae), Corallina (coralline algae), Sertularia (bryozoans and hydrozoans), Hydra (hydras, cilliates and rotifers), Pennatula (sea pens), Taenia (tapeworms), Volvox (volvox algae and amLinebae).

Some species in Linnaeus’ order Zoophyta were (from left to right, top to bottom): the Venus sea fan (Gorgonia flabellum), the dead man’s fingers (Alcyonium digitatum), the oaten pipe hydroid (Tubullaria indivisa), the leafy bryozoan (Eschara foliacea, now Flustra foliacea), the coral weed (Corallina officinalis), the squirrel’s tail (Sertularia argentea), the grooved vorticella (Hydra convallaria, now Vorticella convallaria), the phosphorescent sea pen (Pennatula phosphorea), the pork tapeworm (Taenia solium), and the globe volvox (Volvox globator). Credits to Greg Grimes (sea fan), Bengt Littorin (dead man’s fingers), Bernard Picton (pipe hydroid, sea pen), biopix.com (bryozoan), Lovell and Libby Langstroth (coral weed), National Museums Northern Ireland (squirrel’s tail), D. J. Patterson (vorticella and volvox), Pulich Health Image Library (tapeworm).

Some species in Linnaeus’ order Zoophyta were (from left to right, top to bottom): the Venus sea fan (Gorgonia flabellum), the dead man’s fingers (Alcyonium digitatum), the oaten pipe hydroid (Tubullaria indivisa), the leafy bryozoan (Eschara foliacea, now Flustra foliacea), the coral weed (Corallina officinalis), the squirrel’s tail (Sertularia argentea), the grooved vorticella (Hydra convallaria, now Vorticella convallaria), the phosphorescent sea pen (Pennatula phosphorea), the pork tapeworm (Taenia solium), and the globe volvox (Volvox globator). Credits to Greg Grimes (sea fan), Bengt Littorin (dead man’s fingers), Bernard Picton (pipe hydroid, sea pen), biopix.com (bryozoan), Lovell and Libby Langstroth (coral weed), National Museums Northern Ireland (squirrel’s tail), D. J. Patterson (vorticella and volvox), Pulich Health Image Library (tapeworm).

Linnaeus may have made some mistakes while classifying mammals, birds, amphibians, fishes and insects, but nothing compares to the mess that his class Vermes was. It included animals from many different phyla and even red and green algae! Sometimes the same genus included both animals and plants.

And this concludes our presentation of animals in Linnaeus’ 1758 edition of Systema Naturae.

– – –

References:

Linnaeus. 1758. Systema Naturae per Regna Tria Naturae…

– – –

Creative Commons License
All images are licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.

3 Comments

Filed under Algae, Systematics, Zoology

Friday Fellow: Lined Chiton

by Piter Kehoma Boll

Let’s return to our soft-bodied fellows, the mollusks, and present one of the most beautiful of them, the lined chiton, Tonicella lineata.

As a typical chiton, it has a shell composed of a row of eight overlapping plates sorrounded by a flexible structure, the girdle. Such an anatomy allows those animals to be flexible and even curl up into a ball, just like a woodlouse, when dislodged.

Tonicella lineata, a small sea jewel. Credits to Kirt L. Onthank

Tonicella lineata, a small sea jewel. Credits to Kirt L. Onthank*

Occurring in intertidal and subtidal waters of the North Pacific, in North America, Russia and Japan, the lined chiton is characterized by its beautiful colors. The shell plates are marked by a series of black, purple or blue lines on a red or brown background. The girdle is also colorful, having a reddish background often marked with yellow patches.

Despite its colorful body, the lined chiton is a small creature, reaching about 5 centimeters in length. It feeds mainly on coralline algae, occurring close to them. Its main predators are the terrible sea stars while its closest friends are the spiny but friendly sea urchins, as they usually help the chiton to protect against the sun by allowing them to hide beneath them.

– – –

References:

Barnes, J. R. 1972. Ecology and reproductive biology of Tonicella lineata (Wood, 1815) (Mollusca-Polyplacophora). PhD Thesis.

Wikipedia. Tonicella lineata. Available at < https://en.wikipedia.org/wiki/Tonicella_lineata >. Access on March 03, 2016.

– – –

Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.

Leave a comment

Filed under Friday Fellow, mollusks

Friday Fellow: ‘Orange Jaguar Snail’

by Piter Kehoma Boll

ResearchBlogging.orgLast week I introduced a land planarian that feeds on land snails, Obama ladislavii, or, as I called it, the Ladislau’s flatworm. Therefore, today, I thought it would be great to present a similar situation occurring backwards: a land snail that feeds on land planarians.

So let me introduce this little predator, the land snail Rectartemon depressus. Again, it is not a widely known species and thus it has no common names, but why not call it the ‘orange jaguar snail’? Species of the genus Euglandina, which are also predatory snails, are called ‘wolf snails’ by comparing them to a common predator in North America. As Rectartemon species are common in South America, we could perfectly call them ‘jaguar snails’, right?

Rectartemon depressus about to capture a land planarian Obama marmorata. Photo from Lemos et al., 2012

Rectartemon depressus about to capture a land planarian Obama marmorata. Photo extracted from Lemos et al., 2012

Found in areas of Atlantic Rainforest in Brazil, the orange jaguar snail has a yellow to orange body and a whitish shell. It is listed a vulnerable species in the Brazilian Red List, but it is not mentioned in the IUCN’s Red List.

Initially known as a predator of other land gastropods, the orange jaguar snail revealed a new item in its diet recently. During attempts to find the food items in the diet of some land planarians from southern Brazil, the orange jaguar snail was offered as a food option, but while the expectations were that the planarian would eat the snail, the opposite happened! After contacting the land planarian, the snail simply grasps it with its radula (the snail’s toothed tongue) and sucks it in very quickly, just as if it were eating a noodle!

The orange jaguar snail eagerly consumes several land planarians, both native and exotic species. It makes it one of the first known predators of land planarians. One of its prey is the Ladislau’s flatworm, so we have a snail that eats a flatworm that eats snails!

– – –

References:

Lemos, V., Canello, R., & Leal-Zanchet, A. 2012. Carnivore mollusks as natural enemies of invasive land flatworms. Annals of Applied Biology, 161 (2), 127-131 DOI: 10.1111/j.1744-7348.2012.00556.x

Santos, S. B., Miyahira, I. C., Mansur, M. C. D. 2013. Freshwater and terrestrial molluscs in Brasil: current status of knowledge and conservation. Tentacle, 21, 40-42.

Leave a comment

Filed under Behavior, Conservation, Ecology, Friday Fellow