Tag Archives: invertebrates

Friday Fellow: Bootlace Worm

by Piter Kehoma Boll

Long ago I presented some of the extremes of the animal world, including the largest, the cutest and the leggiest. Now it’s time to introduce another extreme: the longest. And this animal is so long that it seems impossible. Its name: Lineus longissimus, commonly known as bootlace worm. Its length: up to 55 meters.

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An entangled bootlace worm. Photo by Bruno C. Vellutini.*

The bootlace worm is a member of the phylum Nemertea, commonly known as ribbon worms, and is found along the shores of the Atlantic Ocean in Europe. Most of the time, the worm is contracted, forming what looks like a heap of entagled wool threads that has no more than 30 cm from side to side. Although there are reports of specimens measuring more than 50 m, most of them are much shorter, with 30 m being already a very large size. Its width is of about 0.5 cm, so it is almost literally a long brown thread.

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Lineus longissimus photographed in Norway. Photo by Guido Schmitz.**

As all nemerteans, the bootlace worm is a predator and hunts its prey between the rocks on sandy shores, stunning them with its long poisonous proboscis and then swallowing them whole. Soft and fragile, the bootlace worm has no way to protect itself from predators using any physical defense, but it is known to have a series of different toxins on its epidermis, including some similar to the deadly pufferfish poison tetrodotoxin (TTX) that is produced by bacteria living in the mucus that surrounds the body of the worm.

Now, before leaving, take a look at this video of a bootlace worm swallowing a polychaete:

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References:

Cantell, C.-E. (1976) Complementary description of the morphology of Lineus longissimus (Gunnerus, 1770) with some remarks on the cutis layer in heteronemertines. Zoologica Scripta 5:117–120. https://dx.doi.org/10.1111/j.1463-6409.1976.tb00688.x

Carroll, S.; McEvoy, E. G.; Gibson, R. (2003) The production of tetrodotoxin-like substances by nemertean worms in conjunction with bacteria. Journal of Experimental Marine Biology and Ecology 288: 51–63. https://dx.doi.org/10.1016/S0022-0981(02)00595-6

Gittenberger, A.; Schipper, C. (2008) Long live Linnaeus, Lineus longissimus (Gunnerus, 1770) (Vermes: Nemertea: Anopla: Heteronemertea: Lineidae), the longest animal worldwide and its relatives occurring in The Netherlands. Zoologische Mededelingen. Leiden 82: 59–63.

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Friday Fellow: Portuguese Man o’ War

by Piter Kehoma Boll

And so we finally reached the 100th Friday Fellow! In order to commemorate, we will have two Friday Fellows today, just as we had during the 50th one. And to start I chose a cnidarian that always caught me attention.

Living in the Atlantic Ocean and known popularly as Portuguese man o’ war, its binomial name is Physalia physalis, both words derived from the Greek word for bubble, physalis. And the Portuguese man o’ war is, in fact, like a floating bubble with some stuff attached, or at least it looks like that.

Physalia_physalis2

A Portuguese man o’ war lying on the beach. Photo by Anna Hesser.*

Most people may think that the Portuguese man o’ war is a jellyfish due to its looks, but it is actually part of another group of cnidarians, the siphonophores. Their body is not a single individual, but rather a colony of several smaller animals, called zooids, which are speciallized to have different functions within the colony and cannot live separately. They are all derived from the same embryo, thus being clones from each other.

The upper portion of the Portuguese man o’ war has a gas-filled sack, which is called the pneumatophore and is the original organism derived directly from the embryo. Below the pneumatophore there are several different kinds of organisms, such as nectophores for swimming, dactylozooids for defense and capture of prey, gonozooid for reproduction and gastrozooids for feeding. The long tentacles, which reach more than 10 m in length, are composed by dactylozooids and fish for prey throughout the water.

Physalia_physalis1

Floating on the sea. Photo by Regine Stiller.*

As other cnidarians, the Portuguese man o’ war has nettle-like cells which sting and inject venom. In humans, the venom usually cause pain and let whip-like marks on the skin where the tentacles touched. Sometimes more severe complications will results and in rare cases it may result in death.

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References:

Stein, M. R.; Marraccini, J. V.; Rothschild, N. E.; Burnett, J. W. (1989) Fatal portuguese man-o’-war (Physalia physalis) envenomation. Annals of Emergency Medicine 18(3): 312–315.

Wikipedia. Portuguese man o’ war. Available at <https://en.wikipedia.org/wiki/Portuguese_man_o%27_war&gt;. Access on June 16, 2017.

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Friday Fellow: Brown-gutted Mud Roundworm

by Piter Kehoma Boll

If you have your face buried in the mud at the bottom of a European lake, you may end up finding some of those tiny little roundworms known as Monhystera stagnalis. As usual, there is no common name for this species, but I decided to call it brown-gutted mud roundworm. Why? Because it lives in the mud and has a reddish-brown gut.

monhystera_stagnalis

An individual of Monhystera stagnalis. Photo by Marco Spiller.*

The brown-gutted mud roundworm is a widely distributed roundworm species, being common especially throughout Europe. It inhabits the fine sediments at the bottom of freshwater bodies, both stagnant and flowing, where it feeds on the organic material deposit in this medium, having a special taste for bacteria. It is able to survive in moderate organic pollution, but is sensitive to low oxygen levels.

It is one of the most common nematode species in its environment and it is very small, measuring around 1 mm in length, females being slightly longer than males. They are found in all depths of the sediment and seem to have a preference for staying closer to the surface during winter and deeper in the mud during summer.

Females are ovoviviparous, meaning that they retain the egg inside their bodies until they hatch, so they are pregnant with eggs. Although we are used to think that invertebrates produce hundreds or thousands of eggs at once, this is not the case with the brown-gutted mud roundworm. Females are usually pregnant of a single egg, sometimes with two or three. They are modest worms.

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ResearchBlogging.orgReferences:

Pehofer, H. (1989). Spatial Distribution of the Nematode Fauna and Production of Three Nematodes (Tobrilus gracilis, Monhystera stagnalis, Ethmolaimus pratensis) in the Profundal of Piburger See (Austria, 913 m a.s.l) Internationale Revue der gesamten Hydrobiologie und Hydrographie, 74 (2), 135-168 DOI: 10.1002/iroh.19890740203

Traunspurger, W. (1996). Autecology of Monhystera paludicola De Man, 1880 – Seasonal, Bathymetric and Vertical Distribution of a Free-living Nematode in an Oligotrophic Lake Internationale Revue der gesamten Hydrobiologie und Hydrographie, 81 (2), 199-211 DOI: 10.1002/iroh.19960810205

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Friday Fellow: Sun Beetle

ResearchBlogging.orgby Piter Kehoma Boll

Who says beetles cannot be cute? Take a look at those guys:

pachnoda_marginata

They are eating a piece of banana. Photo by Wikimedia user Evanherk.*

These little fellows are beetles of the species Pachnoda marginata, commonly known as sun beetle or taxi cab beetle. Native from Africa, they reach up to 30 mm as adults and 60 mm as larvae and are one of the most common beetles raised as pets.

pachnoda_marginata_peregrina

An adult with the wings exposed, about to fly. Photo by Wikimedia user Drägüs.*

The sun beetle has nine subspecies, each with a particular color pattern. The most well known subspecies is Pachnoda marginata peregrina and is the one shown in the photos above.

Since the sun beetle is easy to keep in the lab, it has been eventually used in scientific studies, especially some related to the neurology of the olphactory receptors.

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References:

Larsson, M. C., Stensmyr, M.. C., Bice, S. B., & Hansson, B. S. (2003). Attractiveness of Fruit and Flower Odorants Detected by Olfactory Receptor Neurons in the Fruit Chafer Pachnoda marginata Journal of Chemical Ecology, 29 (5), 1253-1268 DOI: 10.1023/A:1023893926038

Stensmyr, Marcus C., Larsson, Mattias C., Bice, Shannon, & Hansson, Bill S. (2001). Detection of fruit- and flower-emitted volatiles by olfactory receptor neurons in the polyphagous fruit chafer Pachnoda marginata (Coleoptera: Cetoniinae) Journal of Comparative Physiology A, 187 (7), 509-519

Wikipedia. Pachnoda marginata. Availabe at: < https://en.wikipedia.org/wiki/Pachnoda_marginata >. Access on September 8, 2016.

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New Species: September 11 to 20

by Piter Kehoma Boll

Here is a list of species described from September 11 to September 20. It certainly does not include all described species. Most information comes from the journals Mycokeys, Phytokeys, Zookeys, Phytotaxa, Zootaxa, International Journal of Systematic and Evolutionary Microbiology, and Systematic and Applied Microbiology, as well as journals restricted to certain taxa.

petrolisthes-paulayi

Petrolisthes paulayi is a new crab described in the past 10 days.

SARs

Plants

Amoebozoans

Fungi

Sponges

Cnidaria

Flatworms

Annelids

Nematodes

Arachnids

Myriapods

Crustaceans

Hexapods

Cartilaginous fishes

Ray-finned fishes

Lissamphibians

Reptiles

Mammals

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Friday Fellow: Helicopter Damselfly

ResearchBlogging.orgby Piter Kehoma Boll

Damselflies are usually delicate versions of dragonflies, but some species challenge their place among the odonates. The most extreme example comes from the moist forests of Central and South America and is known as Megaloprepus caerulatus or the “helicopter damselfly”.

With a wingspan up to 19 cm, the helicopter damselfly is the largest of odonates and a voracious predator in both the aquatic naiad and the aerial adult forms.

megaloprepus_caerulatus

An adult female. Photo by Steven G. Johnson*

Female helicopter damselflies lay their eggs in water-filled tree hollows. Males are territorialists and defend the larger holes as territory, mating with females interested in laying eggs there.

The aquatic juvenile stage, known as naiad or nymph, is a top predator in this reduced ecosystem, feeding on mosquito larvae, tadoples and even other odonates. As adults, they feed mainly on web-building spiders that they capture in areas that receive direct sunlight, such as forest glades.

As the population size of the helicopter damselfly depends on the number and size of available tree hollows and considering that they avoid crossing large gaps between forest patches, any environmental disturbance may have profound impacts on this species. Recent molecular studies also suggest that what is known as Megaloprepus caerulatus is actually a complex of species, as there is no genetic flow between the populations. This makes it (or them) a much more vulnerable species.

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References:

Feindt, W., Fincke, O., & Hadrys, H. (2013). Still a one species genus? Strong genetic diversification in the world’s largest living odonate, the Neotropical damselfly Megaloprepus caerulatus Conservation Genetics, 15 (2), 469-481 DOI: 10.1007/s10592-013-0554-z

Wikipedia. Megaloprepus caerulatus. Available at < https://en.wikipedia.org/wiki/Megaloprepus_caerulatus >. Access on September 7, 2016.

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Friday Fellow: Six-Spot Burnet

ResearchBlogging.orgby Piter Kehoma Boll

Found in Europe, today’s Friday Fellow is a nice day-flying moth with beautiful colors and toxic compounds. Scientifically known as Zygaena filipendulae, its common name is six-spot burnet, burnet being the common name of moths in the genus Zygaena and six-spot referring to the six red spots in each of the front wings. Those spots contrast beautifully with the dark blue or green metalic background of the wings, giving it some sort of mystical look, don’t you think?

The color say "I'm not edible". Photo by Vlad Proklov.*

The colors say “I’m not edible”. Photo by Vlad Proklov.*

As a caterpillar, the six-spot burnet feeds on leguminous plants, especially trefoils, and has a very different appearance, as usually in lepidopterans. It is yellow to greenish-yellow and has two rows of black spots running on the dorsum.

A chubby yellow caterpillar. Photo by Harald Süpfle.**

A chubby yellow caterpillar. Photo by Harald Süpfle.**

The plants used as food by the caterpillar contain cyanogenic glucosides, substances that are stored individually and produce toxic hydrogen cyanide when in contact with each other. This is used as a defense mechanism by the plant, but the caterpillar ingests and stores such compounds to use for its own defense. It has also been shown that the caterpillar is able to produce these cyanogenic glucosides by itself, thus not relying solely on the portion ingested with the food. Most of the compounds, however, are lost during the metamorphosis, so that the adults are much less toxic than the caterpillars.

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References:

Zagrobelny, M., Bak, S., Olsen, C., & Møller, B. (2007). Intimate roles for cyanogenic glucosides in the life cycle of Zygaena filipendulae (Lepidoptera, Zygaenidae) Insect Biochemistry and Molecular Biology, 37 (11), 1189-1197 DOI: 10.1016/j.ibmb.2007.07.008

Wikipedia. Six-spot burnet. Available at: < https://en.wikipedia.org/wiki/Six-spot_burnet >. Access on August 1, 2016.

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