Monthly Archives: December 2017

Friday Fellow: Tulip Cone

by Piter Kehoma Boll

The year has almost ended, but if you would touch today’s Friday Fellow, it would end for you right now, and without a new year coming.

Living along the coasts of the Indian Ocean, including East Africa, Madagascar,  India, West Australia and several archipelagos such as Mascarene Islands and the Philippines, our fellow, Conus tulipa, is popularly known as tulip cone. Despite its beautiful name, however, it is not a nice species to have nearby.

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A live Conus tulipa in La Réunion, Mascarene Islands. Photo by Philippe Bourjon.*

The tulip cone is a species of the genus Conus, predatory sea snails that feed on a variety of animals, such as fish, worms and other mollusks. They capture prey by stinging them with a venomous harpoon that is made of a modified tooth of their radula (tongue). The harpoons are stored in a sack and shot on a nearby prey. Because many species feed on fast moving prey, such as fish, they have a very powerful venom able to kill the target in a few seconds. In some species, including the tulip cone, this powerful venom is strong enough to kill an adult human being.

As with all other venomous species, though, not everything is bad. Several different toxins and other components have been recently isolated from the venom of the tulip cone, many of which may eventually be used to develop new medicines.

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References:

Alonso, D.; Khalil, Z.; Satkunanthan, N.; Livett, B. G. (2003) Drugs From the Sea: Conotoxins as Drug Leads for Neuropathic Pain and Other Neurological Conditions. Mini Reviews in Medicinal Chemistry3: 785–787.

Dutertre, S.; Croker, D.; Daly, N. L., Anderson, Å,.; Muttenhaler, M.; Lumsden, N. G.; Craik, D. J.; Alewood, P. F.; Guillon, G.; Lewis, R. J. (2008) Conopressin-T from Conus tulipa reveals an anatagonist switch in vasopressin-like peptides. Journal of Biological Chemistry283, 7100–7108.

Hill, J. M.; Alewood, P. F.; Craik, D. J. (2000) Conotoxin TVIIA, a novel peptide from the venom of Conus tulipa. The FEBS Journal, 267 (15): 4649–4657.

Wikipedia. Conus tulipa. Available at < https://en.wikipedia.org/wiki/Conus_tulipa >. Access on December 28, 2017.

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Friday Fellow: Yerba Mate

by Piter Kehoma Boll

Christmas is in a few days and a plant that is always associated to this time of the year in Europe is the holly Ilex aquifolium. I was about to make it today’s Friday Fellow, but then I thought: why not a less popular but much cooler relative?

So let’s welcome Ilex paraguariensis, the yerba mate!

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Detail of a branch of yerba mate (Ilex paraguariensis). Photo by Leandro Kibisz.*

The yerba mate is a shrub or tree that can grow up to 15 meters in height and is found in several forest fosrmations of South America, especially along the Paraguay and Paraná rivers. The leaves are oval and have a dark green color and a slightly serrated margin. The flowers are mall and lack petals and the fruits are red as in its European cousin.

The leaves of yerba mate are used for the preparation of a traditional beverage called mate in both Spanish and Portuguese, and also as chimarrão in Portuguese. It is traditionally consumed in Paraguay, Argentina, Uruguay and Southern Brazil, as well as in some areas of Bolivia and Chile. The consumption of mate started with the guarani people and later  spread to the Tupi and to the European colonizers and is currently associated with the gaucho culture in South America.

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A man drinking mate. Photo by Aslam Singh.**

The leaves of yerba mate are rich in caffeine and polyphenols, thus having stimulant, diuretic and antioxidant properties. The beverage seems to be able to help in weight loss by reducing the absorption of lipids and can also reduz the risk os several types of cancer. However, there are some evidence connecting the consumption of mate with increased risk of some cancers as well, such as oral and esophageal cancer. This risk, however, may be more related to the temperature of the beverage than the plant itself, so try not to drink it too hot!

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References:

Heck, C. I.; De Mejia, E. G. Yerba Mate Tea (Ilex paraguariensis): A Comprehensive Review on Chemistry, Health Implications, and Technological Considerations. Journal of Food Science, 72(9):R138–R151. DOI: 10.1111/j.1750-3841.2007.00535.x

Wikipedia. Yerba mate. Available at < https://en.wikipedia.org/wiki/Yerba_mate >. Access on December 17, 2017.

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Friday Fellow: Hay bacillus

by Piter Kehoma Boll

Today we’ll return to the tiny world of the bacteria once more. And I guess it is a good time to introduce another celebrity from the bacterial world, the hay bacillus or grass bacillus, Bacillus subtilis.

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Several colonies of Bacillus subtilis on agar. Photo by Wikimedia user Debivort.*

As any typical Bacillus, the hay bacillus has rod-shaped cells, hence the name. They measure about 4–10 µm in length and 0.25–1.0 µm in diameter and have many flagella, so they can move quickly in a liquid medium. The natural habitat of the hay bacillus is the soil, but it can also be found in the intestine of mammals, including humans.

As it is common among the members of the phylum Firmicutes, the hay bacillus is able to enter in a dormant form called endospore that is able to tolerate extreme environmental conditions. They can survive in this form for decades, centuries, perhaps even millenia, until the conditions are adequate again.

bacillus_subtilis_spore

Microscopic image showing vegetative (red) and endospores (green) of Bacillus subtilis. Photo by Wikimedia user Y tambe.*

The hay bacillus is one of the most studied and cultivated bacterium in the world, being considered a model organism. In East Asia, one of its varieties is used in the production of the Japanese traditional food nattō. Before the introduction of antibiotics, it was common to use cultures of B. subtilis in treatments to improve immunological responses. Currently, it is used in laboratory studies focused on the formation of endospores and the phenomenon of transformation, a process by which a bacterium can capture DNA from the medium in which it is and incorporate it into its own genetic material. Additionally, it is used to produce a variety of substances, including naturally produced antibiotics.

Our fellow is indeed a good friend for us.

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References:

Anagnostopoulos, C.; Spizizen, J. (1961) Requirements for transformation in Bacillus subitilisJournal of Bacteriology81(5): 741–746.

Stein, T. (2005) Bacillus subtilis antibiotics: structures, syntheses and specific functions. Molecular Biology56: 845–857. https://dx.doi.org/10.1111/j.1365-2958.2005.04587.x

Wikipedia. Bacillus subtilis. Available at < https://en.wikipedia.org/wiki/Bacillus_subtilis >. Access on November 9, 2017.

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Friday Fellow: Large Roundworm of Pigs

by Piter Kehoma Boll

It’s time to go back to the roundworms and to the parasites once more. Probably one of the most famous roundwors is the large roundworm of humans, Ascaris lumbricoides, but today I’m going to talk about its closest relative, the large roundworm of pigs, Ascaris suum.

Found worlwide, the large roundworm of pigs, as its name implies, infects pigs. It is a large worm of the phylum Nematoda and is very similar to the large roundworm of humans, the main difference being simply that the former infects pigs and the latter infects humans.

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A typical male (top) and female (bottom) of Ascaris suum. Photo by Wikimedia user VlaminckJ.*

The adult worms live in the intestine of pigs and show sexual dimorphism. Males are smaller, measuring 13–31 cm in length and have a curled posterior end. Females are larger, measuring 20–49 cm and do not have the curled posterior end. They have a light pink to whitish color and may occur in large quantities inside the host.

When sexually mature, a female can lay up to 200 thousand eggs per day and have up to 27 million eggs in its uteri. The eggs are eliminated with the pig feces and remain in the environment where the embryo starts its development. As soon as the eggs are eaten by a pigg, the eggs hatch and the larvae crawl into the walls of the large intestine and reach the bloodstream, being carried to the liver and from there to the lungs. In the lungs, they reach the alveoli and start to migrate upward toward the trachaea and are coughed up and swallowed by the pig, reaching the intestine again. There, they remain in the small intestine and complete their development into adults.

The great similarity of Ascaris suum and Ascaris lumbricoides implicate that they have a recent common ancestor which may have split into the two species after humans started to raise pigs. Eventually Ascaris suum may also infect humans and Ascaris lumbricoides may infect pigs too, but they seem to have a preference and an improved development in their “traditional” host. Molecular studies indicate that the populations of both species seem to be considerable isolated, but there have been some eventual hybridizations, suggesting that they are yet in the process of become fully separate species.

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References:

Leles, D.; Gardner, S. L.; Reinhard, K.; Iñiguez, A.; Araujo, A. (2012) Are Ascaris lumbricoides and Ascaris suum a single species? Parasite and Vector5: 42. https://dx.doi.org/10.1186/1756-3305-5-42

Wikipedia. Ascaris suum. Available at: < https://en.wikipedia.org/wiki/Ascaris_suum >. Access on November 6, 2017.

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The history of Systematics: Plants in Systema Naturae, 1758 (Part 7)

by Piter Kehoma Boll

We are approaching the end of the description of Linnaeus’ classification of Plants (see parts 1, 2, 3, 4, 5 and 6). Today I’ll show two more classes, the last two of plants with mainly hermaphrodite flowers.

19. Syngenesia (“same generation”)

“Husbands composed of a generative compact”, i.e., the stamens are united, forming a cylinder.

19.1 Syngenesia Polygamia Aequalis (“same generation, many equal marriages”), compound flowers formed by several small compact flowers, all having stamens and pistils: Scolymus (golden thistles), Cichorium (chicories), Catananche (cupid’s darts), Hypochaeris (cat’s ears), Andryala (andryalas), Tragopogon (goatsbeards), Picris (oxtongues), Leontodon (hawkbits and dandelions), Sonchus (sow thistles), Scorzonera (salsifies), Crepis (hawksbeards), Chondrilla (skeletonweeds), Prenanthes (rattlesnake roots), Lactuca (lettuces), Hieracium (hawkweeds), Lapsana (nippleworts), Hyoseris (hyoserises), Elephantopus (elephant’s foot), Atractylis (spindle thistles), Carlina (carline thistles), Cnicus (thistles), Arctium (burdocks), Carthamus (distaff thistles), Cynara (alcachofras), Carduus (more thistles), Onopordum (cotton thistles), Serratula (plumeless saw-worts), Echinops (globe thistles), Ageratum (whiteweeds), Cacalia (false plantains), Chrysocoma (goldenhairs), Eupatorium (thoroughworts), Santolina (cotton lavenders), Bidens (beggarticks), Staehelina (staehelinas), Stoebe (stoebes), Tarchonanthus (camphor bush).

1758Linnaeus_syngenesia_polygamia_aequalis

The diverse order Syngenesia Polygamia Aequalis included (from left to right, top to bottom) the common goatsbeard (Tragopogon porrifolius), black salsify (Scorzonera hispanica), bristly oxtongue (Picris echioides, now Helminthotheca echioides), common sowthistle (Sonchus oleraceus), garden lettuce (Lactuca sativa), rush skeletonweed (Chondrilla juncea), common rattlesnake root (Prenanthes purpurea), common dandelion (Leontodon taraxacum, now Taraxacum officinale), rattlesnake hawkweed (Hieracium venosum), beaked hawksbeard (Crepis vesicaria), common andryala (Andryala integrifolia), smooth hyoseris (Hyoseris scabra), common cat’s ear (Hypochaeris radicata), common nipplewort (Lapsana communis), blue cupid’s dart (Catananche caerulea), common chicory (Cichorium intybus), Spanish golden thistle (Scolimus hispanicus), smooth elephant’s foot (Elephantopus scaber), great globe thistle (Echinops sphaerocephalus), great burdock (Arctium lappa), dyer’s plumeless saw-wort (Serratula tinctoria), musk thistle (Carduus nutans), holy thistle (Cnicus benedictus, now Centaurea benedicta), common cotton thistle (Onopordum acanthium), globe artichoke (Cynara scolymus), common carline thistle (Carlina vulgaris), common spindle thistle (Atractylus huilis), safflower (Carthamus tinctorius), common beggartick (Bidens pilosa), Alpine plantain (Cacalia alpina, now Adenostyles alpina), tall thoroughwort (Eupatorium altissimum), common whiteweed (Ageratum conyzoides), dubious staehelina (Staehelina dubia), common goldenhair (Chrysocoma coma-aurea), camphor bush (Tarchonanthus camphoratus), and common cotton lavender (Santolina chamaecyparissus). Credits to Stephen Lea (goatsbeard), H. Zell (salsify, lettuce, cotton thistle), Tony Wills (sow thistle), Radio Toreng (skeletonweed), Jane Shelby Richardson (hawkweed), Manfred Moitzi (hawksbeard), Pablo Alberto Salguero Quilles (andryala), smooth hyoseris (Hyoseris scabra), Javier Martin (hyoseris, spindle thistle), Phil Sellens (nipplewort), Isidre Blanc (cupid’s dart, staehelina), Joaquim Alves Gaspar (chicory, golden thistle, globe artichoke), Dinesh Valke (elephant’s foot), Enrico Blasutto (burdock), Kristian Peters (plumeless saw-wort), Bernd Haynold (musk thistle), Philipp Weigell (carline thistle), Vishesh Bajpai (beggartick),Benjammin Zwittnig (Alpine plantain), Frank Mayfield (thoroughwort), Peter A. Mansfeld (goldenhair), Paul Venter (camphor bush), Marie-Lan Nguyen (cotton lavender), and Wikimedia users AnemoneProjectors (oxtongue, cat’s ear), Calimo (rattlesnake root), Kropsoq (dandelion), Epp (globe thistle), 00temari (holy thistle), Pseudoanas (safflower) and Leoadec (whiteweed).*

19.2 Syngenesia Polygamia Superflua (“same generation, many remaining marriages”), compound flowers formed by several small compact flowers forming a central disk of hermaphrodite flowers surrounded by a ring of feminine flowers. Both hermaphrodite and feminine flowers are fertile and produce seeds: Tanacetum (tansies), Artemisia (artemisias), Gnaphalium (cudweeds), Xeranthemum (dry everlastings), Carpesium (carpesiums), Baccharis (baccharises), Conyza (horseweeds), Erigeron (fleabanes), Tussilago (coltsfoots), Senecio (ragworts and groundsels), Aster (asters), Solidago (goldenrods), Inula (inulas), Arnica (arnicas), Doronicum (leopard’s banes), Helenium (sneezeweeds), Bellis (daisies), Tagetes (marigolds), Zinnia (zinnias), Pectis (cinchweeds), Chrysanthemum (chrysanthemums and daisies), Matricaria (chamomiles), Cotula (water buttons), Anacyclus (anacycles), Anthemis (false chamomiles), Achillea (yarrows), Tridax (coatbuttons), Amellus (amelluses), Sigesbeckia (St. Paul’s worts), Verbesina (crownbeards), Tetragonotheca (neverays), Buphthalmum (ox-eyes).

1758Linnaeus_syngenesia_polygamia_superflua

Linnaeus put this species in the order Syngenesia Polygamia Superflua (from left to right, top to bottom): common tansy (Tanacetum vulgare), wormwood (Artemisia absinthium), heath cudweed (Gnaphalium sylvaticum), annual dry everlasting (Xeranthemum anuum), saltbush (Baccharis halimifolia), one-flower fleabane (Erigeron uniflorus), common coltsfoot (Tussilago farfara), common groundsel (Senecio vulgaris), Italian aster (Aster amellus), seaside goldenrod (Solidago sempervirens), hairy inula (Inula hirta), mountain arnica (Arnica montana), common leopard’s bane (Doronicum pardalianches), common sneezeweed (Helenium autumnale), common daisy (Bellis perennis), French marigold (Tagetes patula), Peruvian zinnia (Zinnia peruviana), Indian chrysanthemum (Chrysanthemum indicum), common chamomile (Matricaria chamomilla), buttonweed (Cotula coronopifolia), common anacycle (Anacyclus valentinus), sea false-chamomile (Anthemis maritima), common yarrow (Achillea millefolium), coatbuttons (Tridax procumbens), eastern St. Paul’s wort (Siegesbeckia orientalis), ox-eye (Buphthalmum salicifolium>). Credits to Muriel Bendel (tansy), Hermann Schachner (cudweed), Musa Geçit (dry everlasting), Bob Peterson (saltbush, coatbuttons), André Karwath (coltsfoot, daisy), C T Johansson (aster), Sam Fraser-Smith (goldenrod), Kurt Stüber (inula), Isidre Blanc (arnica), Agnieszka Kwiecien (sneezeweed), Lynda Poulter (chamomile), Walter Siegmund (buttonweed), Denis Barthel (false-chamomile), Petar Milošević (yarrow), and Wikimedia users N-Baudet (wormwood), Ghislain118 (fleabane), AnRo0002 (groundsel), Jamain (leopard’s bane, ox-eye), Rasbak (marigold), Vengolis (zinnia), Joydeep (chrysanthemum), Philmarin (anacycle) and Elouanne (St. Paul’s wort).

19.3 Syngenesia Polygamia Frustranea (“same generation, many marriages in vain”), compound flowers formed by several small compact flowers forming a central disk of hermaphrodite flowers surrounded by a ring of neutral flowers, without sexual organs, therefore only the flowers of the disk are fertile and produce seeds: Helianthus (sunflowers), Rudbeckia (black-eyed-susans), Coreopsis (coreopsises), Gorteria (gorterias), Centaurea (knapweeds), Gundelia (gundelia).

1758Linnaeus_syngenesia_polygamia_frustranea

The order Syngenesia Polygamia Frustranea included (from left to right) the common sunflower (Helianthus annuus), common black-eyed susan (Rudbeckia hirta), lance-leaved coreopsis (Coreopsis lanceolata), bachelor’s button (Centaurea montana), gundelia (Gundelia tournefortii). Credits to Frank Mayfield (black-eyed susan), Jean-Pol Grandmont (bachelor’s button), Gundelia (gundelia) and Wikimedia users i_am_jim (sunflower) and KENPEI (coreopsis).*

19.4 Syngenesia Polygamia Necessaria (“same generation, many unavoidable marriages”), compound flowers formed by several small compact flowers forming a central disk of hermaphrodite flowers, but whose feminine part is sterile, surrounded by a ring of fertile feminine flowers, therefore only the flowers of the ring produce seeds: Milleria (millerias), Silphium (rosinweeds), Chrysogonum (golden knees), Melampodium (blackfoots), Calendula (pot marigolds), Arctotis (bear’s ears), Osteospermum (daisybushes), Othonna (othonnas), Polymnia (leafcups), Eriocephalus (snow bushes), Filago (cudweeds), Micropus (cotton seeds), Sphaeranthus (ballflowers).

1758Linnaeus_syngenesia_polygamia_necessaria

These 7 species were included by Linnaeus in the order Syngenesia Polygamia Necessaria (from left to right, top to bottom): starry rosinweed (Silphium asteriscus), common golden knee (Chrysogonum virginianum), common pot-marigold (Calendula officinalis), whiteflower leafcup (Polymnia canadensis), Cape snow bush (Eriocephalus africanus), common cudweed (Filago germanica, now Filago vulgaris), Indian ballflower (Sphaeranthus indicus). Credits to James H. Miller (rosinweed), Fritz Flohr Reynolds (golden knee, leafcup), Wouter Hagens (pot marigold), Juanita Vilas Marchant (snow bush), Wim Rubers (cudweed), Dinnesh Valke (balflower).*

19.5 Syngenesia Monogamia (“same generation, one marriage”), stamens united forming a cylinder, but with single flowers, not forming inflorescences: Seriphium (seriphiums), Corymbium (plampers), Jasione (scabiouses), Lobelia (lobelias), Viola (violets and pansies), Impatiens (balsams).

1758Linnaeus_syngenesia_monogamia

The sheep’s scabious (Jasione montana, left), garden lobelia (Lobelia erinus, center left), common violet (Viola odorata, center right), and garden balsam (Impatiens balsamina, right) were part of the order Syngenesia Monogamia. Credits to André Karwath (lobelia), Bernard Dupont (violet) and Wikimedia users Darkone (scabious) and Joydeep (balsam).*

20. Gynandria (“female husband”)

“Husbands monstruously united to women”, i.e., flowers with stamens united to the pistils.

20.1 Gynandria Diandria (“female husband, two husbands”), two stamens united to the pistils: Orchis (orchids), Satyrium (satyre orchids), Ophrys (fly and bee orchids), Serapias (Serapis orchids), Limodorum (grass pinks), Arethusa (dragon’s mouth and snake’s mouths), Cypripedium (lady’s slippers orchids), Epidendrum (epiphytic orchids).

 

1758Linnaeus_gynandria_diandria

The order Gynandria Diandria included (from left to right, top to bottom) the military orchid (Orchis militaris), fly orchid (Ophrys insectifera), tuberous grass pink (Limodorum tuberosum, now Calopogon tuberosus), dragon’s mouth (Arethusa bulbosa), yellow lady’s slipper (Cypripedium calceolus), spathulate vanda (Epidendrum spathulatum, now Taprobanea spathulata). Credits to Holger Krisp (military orchid, fly orchid), Chris Meloche (dragon’s mouth), and Wikimedia users Algirdas (lady’s slipper) and CyberWikipedian (vanda).*

20.2 Gynandria Triandria (“female husband, three husbands”), three stamens united to the pistils: Sisyrinchium (blue-eyed grasses).

20.3 Gynandria Tetrandria (“female husband, four husbands”), four stamens united to the pistils: Nepenthes (pitcher plants).

20.4 Gynandria Pentandria (“female husband, five husbands”), five stamens united to the pistils: Ayenia (ayenias), Passiflora (passion flowers).

1758Linnaeus_gynandria_triandria_tetrandria_pentandria

The common blue-eyed grass (Sisyrinchium bermudianum, left) was the only member of the order Gynandria Triandria. The distiller pitcher-plant (Nepenthes distillatoria, center) was the only member of the order Gynandria Tetrandria. The purple passion flower (Passiflora incarnata) was one of the members of the order Gynandria Pentandria. Credits to Wouter Hagens (blue-eyed grass), James & Jana Hans (pitcher-plant), Oliver P. Quillia (passion flower).*

20.5 Gynandria Hexandria (“female husband, six husbands”), six stamens united to the pistils: Aristolochia (pipevines), Pistia (water lettuce).

20.6 Gynandria Decandria (“female husband, ten husbands”), ten stamens united to the pistils: Helicteres (screw trees).

1758Linnaeus_gynandria_hexandria_decandria

The order Gynandria Hexandria included the smearwort (Aristolochia rotunda, left) and the water lettuce (Pistia stratiotes, center). The order Gynandria Decandria included the Indian screw tree (Helicteres isora, right). Credits to J. M. Garg (screw tree) and Wikimedia users Hectonichus (smearwort) and Keisotyo (water lettuce).*

20.7 Gynandria Polyandria (“female husband, many husbands”), many stamens united to the pistils: Xylopia (xylopias), Grewia (crossberries), Arum (arums), Dracontium (arum yams), Calla (callas), Pothos (pothos), Zostera (eelgrasses).

1758Linnaeus_gynandria_polyandria

The order Gynandria Polyandria included (from left to right) the crossberry (Grewia occidentalis), dragon arum (Arum dracunculus, now Dracunculus vulgaris), elephant-foot yam (Dracontium polyphyllum, now Amorphophallus paeoniifolius), wild calla (Calla palustris) and climbing pothos (Pothos scandens). Credits to P. Pickaert (arum), Kurt Stüber (calla), and Wikimedia users Consultaplantas (crossberry), Fotokannan (yam) and Vinayaraj (pothos).*

As you can see, the class Syngenesia is much more regular than the class Gynandria. Most species of Syngenesia are currently included in the family Asteraceae. Gynandria, on the other hand, includes a variety of unrelated plants, including orchids, arum plants and even passion flowers!

Here we finish all plants with hermaphroditic flowers. We only need two more posts and we will have seen the whole system of Linnaeus!

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References:

Linnaeus, C. (1758) Systema Naturae per regna tria Naturae…

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Friday Fellow: Duckweed Chain Flatworm

by Piter Kehoma Boll

Today we have one more flatworm in our team. It is part of the most bizarre group of flatworms, the so-called Catenulida. Our fellow is called Catenula lemnae, which I adapted as the “duckweed chain flatworm”.

The duckweed chain flatworm is a very small animal, measuring about 0.1 mm in width and about two or three times this size in length. It is found worldwide in freshwater lakes and ponds and is likely a complex of species, but more detailed studies are needed to make it clear. As other catenulids, it lives close to the substract, being considered a benthic animal, and feeds on other smaller organisms, such as small invertebrates and algae. It is usually a dominant species in the community of benthic microanimals, such as microturbellarians, in places where it is found.

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A chain of several connected individuals (zooids) of Catenula lemnae. Photo by Christopher Laumer.*

The word catenula, meaning “little chain” in Latin, was given to these animals because of their peculiar way of vegetative reproduction. The organism frequently divides transversally close to the posterior end, giving rise to new organisms that are genetically identical to the original one. However, the new animals often remain connected to each other for a long time before splitting, and as this asexual reproduction continues, it eventually turn them into a chain of connected individuals (called zooids). This chain swims elegantly using its cilia as if it were a single individual.

Most recent studies mentioning the duckeed chain flatworm are simply surveys of the species composition of a certain area or broad phylogenetic studies on the catenulids or flatworms in general. Little is known about the ecology, behavior and population structuring of this species, unfortunately.

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References:

Braccini, J. A. L.; Leal-Zanchet, A. M. (2013)  Turbellarian assemblages in freshwater lagoons in southern Brazil. Invertebrate Biology132(4): 305–314. https://dx.doi.org/10.1111/ivb.12032

Marcus, E. (1945) Sôbre Catenulida brasileiros. Boletim da Faculdade de Filosofia, Ciências e Letras da Universidade de São Paulo, série Zoologia, 10: 3–113.

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