Friday Fellow: Elegant Claudea

by Piter Kehoma Boll

Today I’m going to introduce you to the possibly most beautiful alga. Its name is Claudea elegans, which I adapted as “elegant claudea” to serve as a popular name.

I first became aware of the existence of such an organism in my childhood when I saw a drawing of it in an encyclopedia. It had a very beautiful shape, a nice pink color and a cute name. But it was simply depicted among several other algae on that page and besides the drawing and the name, nothing else was said.

Drawing of Claudea elegans from Phycologia Australica.

Unfortunately, there is not much information available online on the elegant claudea. It is a marine species found in Australia, Brazil, India, Pakistan and probably many other tropical waters around the world, being usually attached to rocks near sand and in places with a good current flow.

The net of the elegant claudea as seen under the microscope. The small sacs disrupting the net are the tetrasporangia, reproductive structures. Photo by Dr. Robert Ricker, NOAA/NOS/ORR.

It reaches up to 40 cm in height/length and is composed of branched stalks with a very peculiar pattern. The stalk has a sort of net on one of its sides that makes it look like a one-sided feather. The net is formed by many smaller stalks connected to each other by even smaller ones, one those again to each other by the smallest of all. The branches from the main stalk always come out from the opposite side of the net and have themselves a net on one of its sides and smaller stalks growing opposite to it. The elegant claudea is, therefore, somewhat a double fractal.

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References:

Baldock, R. N. Algae revealed: Claudea elegans. State Herbarium S Australia. Availabe at: <http://www.flora.sa.gov.au/efsa/algae_revealed/pdf/Claudea_elegans.pdf&gt;. Access on February 25, 2016.

Pacheco, M. R. 2011. Macroalgas marinhas associadas a bancos de rodolitos do infralitoral do Espírito Santo, Brasil. Doctoral thesis. USP.

Electronic Flora of South Australia: Claudea elegans. Available online at: <http://www.flora.sa.gov.au/efsa/Marine_Benthic_Flora_SA/Part_IIID/Claudea_elegans.shtml&gt;. Access on February 15, 2016.

The history of Systematics: Animals in Systema Naturae, 1758 (part 2)

by Piter Kehoma Boll

This post is a continuation of The history of Systematics: Animals in Systema Naturae, 1758 (part 1). So be sure to read that first!

Here I’ll talk about two other classes in Linnaeus’ classification: Amphibia and Pisces.

3. Amphibia (Amphibians)

Heart with one ventricle and one auricle; cold, red blood.
Lungs breathing arbitrarily.
Jaw incumbent.
Penis double. Eggs mostly membranaceous.
Senses: tongue, nostrils, eyes, many ears.
Covering: coriaceous, nude.
Support: various, in some none.

Amphibians  were classified according to the anatomy of the limbs and included 3 orders: Reptiles, Serpentes, and Nantes. They are shown below with their respective genera.

3.1 Reptiles (crawlers), having four feet : Testudo (turtles and tortoises), Draco (gliding lizards), Lacerta (lizards, salamanders and crocodilians), Rana (frogs and toads).

Four species that Linnaeus put under Reptiles (from left to right): spur-thighed tortoise (Testudo graeca), flying lizard (Draco volans), sand lizard (Lacerta agilis), and common frog (Rana temporaria). Credits to Gisella D. (tortoise), Charles J. Sharp (flying lizard), Krzysztof Mizera (sand lizard), and Monika Betley (frog).

3.2 Serpentes (creepers), without limbs: Crotalus (rattlesnakes), Boa (boas), Coluber (racers, vipers, cobras, pythons), Anguis (slow worms, worm snakes and sand boas), Amphisbaena (worm lizards), Caecilia (caecilians).

Six species put by Linnaeus under Serpentes (from left to right, top to bottom): timber rattlesnake (Crotalus horridus), Boa constrictor, black racer (Coluber constrictor), slow worm (Anguis fragilis), red worm lizard (Amphisbaena alba), and bearded caecilian (Caecilia tentaculata). Credits to Pavel Ševela (boa constrictor), Wikimedia user Marek_bydg (slow worm), Diogo B. Provete (worm lizard)**, and bio-scene.org (bearded cacecilian).

3.2 Nantes (swimmers), having fins: Petromyzon (lampreys), Raja (rays), Squalus (sharks), Chimaera (ratfishes), Lophius (anglerfishes), and Acipenser (sturgeons).

The order Nantes comprised, among others (from left to right, top to bottom), the sea lamprey (Petrozymon marinus), the thornback ray (Raja clavata), the spiny dogfish (Squalus acanthias), the rabbitfish (Chimaera monstrosa), the angler (Lophius piscatorius), and the sturgeon (Acipenser sturio). Credits to Wikimedia user Fungus Guy (lamprey), Wikimedia user Citron (rabbitfish), Wikimedia user Meocrisis (angler), and flickr user Aah-Yeah (sturgeon).

4. Pisces (Fish)

Heart with one ventricle and one auricle; cold red blood.
Gills external, compressed.
Jaw incumbent.
Penis absent. Eggs without albumin.
Senses: tongue, nostrils (?), eyes (no ears).
Covering: imbricate scales.
Support: fins.

Fish included 5 orders, which were defined mainly by the position of the ventral limbs in relation to the pectoral fins: Apodes, Jugulares, Thoracici, Abdominales and Branchiostegi.

4.1 Apodes (footless ones), without ventral fins: Muraena (eels), Gymnotus (knifefishes), Trichiurus (cutlassfishes), Anarhichas (wolffishes), Ammodytes (sand eels), Stromateus (butterfishes), Xiphias (swordfishes).

(From left to right, top to bottom) The Mediterranean muray (Muraena helena), banded knifefish (Gymnotus carapo), largehead hairtail (Trichiurus lepturus), seawolf (Anarhichas lupus), lesser sand eel (Ammodytes tobianus), blue butterfish (Stromateus fiatola), and swordfish (Xiphias gladius) were classified as Apodes. Credits to Tato Grasso (muray), segrestfarms.com (knifefish), Daizu Azuma (hairfail), Wikimedia user Haplochromis (seawolf), and Muhammad Moazzam Khan (swordfish).

4.2 Jugulares (jugular ones), ventral fins in front of the pectoral fins: Callionymus (dragonets and flatheads), Uranoscopus (stargazers), Trachinus (weevers), Gadus (cods, haddocks, lings, etc), Blennius (blennies), Ophidion (cusk-eels, gunnels, bandfishes).

Six species included in the order Jugulares (from left to right, top to bottom): common dragonet (Callionymus lyra), Atlantic stargazer (Uranoscopus scaber), greater weever (Trachinus draco), Atlantic cod (Gadus morhua), butterfly blenny (Blennius ocellaris), snake blenny (Ophidion barbatum). Credits to Hans Hillewaert (dragonet), Roberto Pillon (stargazer), Hans-Petter Fjeld (cod, CC-BY-SA), Gianni Neto (blenny), Stefano Guerrieri (snake blenny).

4.3 Thoracici (thoracic ones), ventral fins below the pectoral fins: Cyclopterus (lumpfishes), Echeneis (remoras), Coryphaena (dolphinfishes and razorfishes), Gobius (gobies), Cottus (sculpins and hooknoses), Scorpaena (scorpionfishes), Zeus (John dories, lookdowns and boar fishes), Pleuronectes (flatfishes), Chaetodon (butterflyfishes, angelfishes, surgeons, etc), Sparus (breams, porgies, picarels, etc), Labrus (wrasses, parrotfishes, etc), Sciaena (snappers and croakers), Perca (perch, groupers, tilapias, etc), Gasterosteus (sticklebacks, lionfishes, pilot fishes, etc), Scomber (mackerels and tunas), Mullus (goatfishes), and Trigla (gurnards).

Seveteen species classified by Linnaeus as Thoracici (from left to right, top to bottom): lumpsucker (Cyclopterus lumpus), live sharksucker (Echeneis naucrates), pompano dolphinfish (Coryphaena equiselis), black goby (Gobius niger), European bullhead (Cottus gobio), bigscale scorpionfish (Scorpaena scrofa), John Dory (Zeus faber), European plaice (Pleuronectes platessa), banded butterflyfish (Chaetodon striatus), gilt-head bream (Sparus aurata), brown wrasse (Labrus merula), brown meagre (Sciaena umbra), European perch (Perca fluviatilis), three-spined stickleback (Gasterosteus aculeatus), Atlantic mackereil (Scomber scombrus), bluntsnouted mullet (Mullus barbatus), and piper gurnard (Trigla lyra). Credits to Simon Pierre Barrette (lumpsucker), Wikimedia user Wusel007 (sharksucker), NOAA/FPIR Observer Program (dolphinfish), Stefano Guerrieri (goby and wrasse), Hans Hillewaert (bullhead), Wikimedia user Elapied (scorpionfish), Wikimedia user Kleines.Opossum (john dory), Wikimedia user Gargolla (plaice), Bernard E. Picton (butterflyfish), Roberto Pillon (bream and mullet), Albert Kok (meagre), Wikimedia user Dgp.martin (perch), Wikimedia user JaySo83 (stickleback), NOAA (mackerel), and Massimiliano Marcelli (gurnard).

4.4 Abdominales (abdominal ones), ventral fins behind the pectoral fins: Cobitis (loaches and four-eyed fishes), Silurus (catfishes), Loricaria (suckermouth catfishes), Salmo (salmon, trouts, smelts, etc), Fistularia (cornetfishes), Esox (pikes, gars, barracudas, etc), Argentina (herring smelts), Atherina (silversides), Mugil (mullets), Exocoetus (flying fishes), Polynemus (threadfins), Clupea (herring, anchovies, hatchetfishes, etc), and Cyprinus (carps, goldfishes, breams, etc).

Thirteen species that were part of the order Abdominales (from left to right, top to bottom): spined loach (Cobitis taenia), Wels catfish (Silurus glanis), suckermouth catfish (Loricaria cataphracta), Atlantic salmon (Salmo salar), bluespotted cornetfish (Fistularia tabacaria), northern pike (Esox lucius), European argentine (Argentina sphyraena), Mediterranean sand smelt (Atherina hepsetus), flathead mullet (Mugil cephalus), Tropical two-winged flying fish (Exocoetus volitans), paradise threadfin (Polynemus paradiseus), Atlantic herring (Clupea harengus), and  common carp (Cyprinus carpio). Credits to J. C. Harf (loach), Dieter Florian (catfish), Hans-Petter Fjeld (salmon), Wikimedia user Jik jik (pike), Roberto Pillon (sand smelt and mullet), Wikimedia user Kolisberg (flying fish), segrestfarms.com (threadfin), and Wikimedia user Kils (herring).

4.5 Branchiostegi, lacking opercula or branchial fins: Mormyrus (elephantfishes), Balistes (triggerfishes and snipefishes), Ostracion (boxfishes, cowfishes, etc), Tetraodon (pufferfishes and sunfishes), Diodon (porcupine fishes), Centriscus (shrimpfishes), Syngnathus (pipefishes and seahorses), and Pegasus (seamoths).

The eight species shown above were all part of the order Branchiostegi (from left to right, top to bottom): Mormyrus caschive, queen triggerfish (Balistes vetula), yellow boxfish (Ostracion cubicus), Fahaka pufferfish (Tetraodon lineatus), spot-fin porcupinefish (Diodon hystrix), grooved shrimpfish (Centriscus scutatus), common pipefish (Syngnathus acus), and longtail seamoth (Pegasus volitans). Credits to Johny Jensen (Mormyrus), James St. John (triggerfish), flickr user zsispeo (boxfish), Reserva de la Biosfera Cabildo de Gran Canaria (porcupinefish), John E. Randall (shrimpfish and seamoth), and Hans Hillewaert (pipefish).

As you can notice, Linnaeus’ classification of amphibians and fish was even worse than that of mammals and birds, especially the classification of amphibians. It is clear that Linnaeus hated what he called amphibians more than anything. He describes them as the worst creatures, having a horrible appearence, and thanking God for not creating many of them.

Probably one of the most bizarre things is that Linnaeus put lizards and crocodiles in the same genus! Well, if he hated “amphibians” so much, I think he was not very familiar with their anatomy.

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Reference:

Linnaeus, Carl. 1758. Systema Naturae per Regna Tria Nature…

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

Friday Fellow: Blue whale

by Piter Kehoma Boll

We’ve talked about the cutest and the leggiest, so now it’s time to introduce the largest, at once.

I think most of us know already that the largest animal ever is our beloved blue whale, Balaenoptera musculus. It can reach 30 m in length and weigh more than 180 tonnes. It’s really big, but probably not as big as many people think. There are some popular legends, like that the heart of a blue whale is the saze of a car or that a human could swim inside its aorta, which are not actually true.

It’s almost impossible to find a good photo of the entire body of a blue whale. Afterall, it’s huge and lives underwater!

But what else can we say about the blue whale? It is a rorqual, a name used to designate whales in the family Balaenopteridae and, as all of them, its main and almost exclusive food is krill, a small crustacean very abundant in all oceans. And krill needs to be abundant in order to provide the thousands of tonnes that all whales in the oceans need to eat every day. A single blue whale eats up to 40 million krill in a day, which equals to roughly 3.5 tonnes. A blue whale calf (young) is born measuring around 7 m in length and drinks around 500 liters of milk per day!

Blue whales were abundant in nearly all oceans until the beginning of the 20th century, when they started to be hunted and were almost extinct. Nowadays, the real population size is hard to estimate, but may encompass as few as 5,000 specimens, much less than the estimated hundreds of thousands in the 19th century. Due to such a drastic reduction in the population, the blue whale is currently listed as “endangered” in IUCN’s Red List.

But let’s see a blue whale in all of its blueness.

Occasionally, blue whales can hybridize with fin whales (Balaenoptera physalus) and perhaps even with humpback whales (Megaptera novaeangliae), a species classified in a different genus! Some recent genetic analyses, however, indicate that the Balaenoptera genus is polyphyletic and the blue whale may become known as Rorqualus musculus.

Different from other whales, blue whales usually live alone or in pairs, but never form groups, even though they may sometimes gather in places with high concentrations of food.

Like other cetaceans, especially other baleen whales, the blue whale sings. The song, however, is not as complex and dynamic as the ones produced by the related humpback whale. An intriguing fact that was recently discovered is that the frequency of the blue whale song is getting lower and lower at least since the 1960s. There is no good hypothesis to explain this phenomenon yet, but several ones have been proposed, such as the increase in background noise due to human activities or the increase in population density due to the decrease in whaling.

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References:

Hassanin, A.; Delsuc, F.; Ropiquet, A.; Hammer, C.; van Vuuren, B. J.; Matthee, C.; Ruiz-Garcia, M.; Catzeflis, F.; Areskoug, V.; Nguyen, T. T.; Couloux, A. 2012. Patter and timing of diversification of Cetartiodactyla (Mammalia, Laurasiatheria), as revealed by a comprehensive analysis of mitochondrial genomes.  Comptes Rendus Biologies, 335: 32-50.

Mellinger, D. K.; Clark, C. W. 2003. Blue whale (Balaenoptera musculus) sounds from the North Atlantic. Journal of the Acoustical Society of America, 114(2): 1108-1119.

Wikipedia. Blue whale. Available at: <https://en.wikipedia.org/wiki/Blue_whale&gt;. Access on January 27, 2016.

 

Friday Fellow: Leggiest Millipede

by Piter Kehoma Boll

When it comes to nature, people are always curious about the superlatives, the extremes. What’s the largest, the smallest, the oldest, the most venomous… But there’s another extreme that people usually don’t think about: the leggiest!

So today we’ll talk about it. The leggiest animal, i.e., the animal with the largest number of legs.

Its scientific name is Illacme plenipes and it lacks a common name, so I decided to call the “leggiest millepede”, since that’s what it is. The name “millipede” means “a thousand feet”, but none of them actually reach that number. I. plenipes, however, comes pretty close, having as much as 750 legs! It is so long and so leggy that watching it move is almost a torture.

A female Illacme plenipes. Photo from Marek et al. (2012).*

This species was described in 1928 from a small locality in California and is so rare that it wasn’t found again for almost 80 years, being rediscovered only in 2005 in an area close to the original one.  Despite having hundreds of legs, it is a very small species, being less than 4cm long. Most examined species have less than 700 legs because of the unusual development found in most or all millipedes.

Like all arthropods, millepedes shed their exoskeleton from time to time to allow them to grow. In millipedes, every time they shed, they increase the number of body segments and legs. It continues throughout their lives, even after becoming sexually mature. Therefore, we could even find some specimens having more than the record of 750 legs!

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References:

Marek, P. E.; Bond, J. E. 2006. Rediscovery of the world’s leggiest animal. Nature, 441: 707. DOI: 10.1038/441707a

Marek, P. E.; Shear, W. A.; Bond, J. E. 2012. A redescription of the leggiest animal, the millipede Illacme plenipes, with notes on its natural history and biogeography. Zookeys, 241: 77-112. DOI: 10.3897/zookeys.241.3831

Wikipedia. Illacme. Available at <https://en.wikipedia.org/wiki/Illacme&gt;. Access on January 26, 2016.

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

The history of Systematics: Animals in Systema Naturae, 1758 (part 1)

by Piter Kehoma Boll

A long time ago, I wrote a post on how the classification of living beings in kingdoms have evolved since Linnaeus until the modern days. It was a brief introduction, not intended to detail it at levels below kingdom. Here, I intend to start a new series of posts where I’ll present the classification of life forms in lower levels. Each post will present a more recent classification compared to the previous one, so that you can see how things evolved through time.

So, let’s start again with Linnaeus, more precisely with the 10th Edition of his work Systema Naturae. This edition is the starting point of zoological nomenclature and was published in 1758.

In the Systema Naturae, Linnaeus divided “nature” in three kingdoms: Regnum Animale (animal kingdom), Regnum Vegetabile (vegetable kingdom) and Regnum Lapideum (mineral kingdom). As minerals are not lifeforms, we’ll not deal with it here, since this classification does not make sense at all for rocks. Maybe I’ll talk about it later in another post.

At first I would present the whole system here, but the post would become too big. Therefore, I decided to present animals and plants separately, but again there was too much to talk on animals. So, this post will deal only with mammals and birds. Other groups will be presented in subsequent posts. See amphibians and fish here, insects here and worms here.

Animals were defined by Linnaeus as having an organized, living and sentient body and being able to move freely. They were classified in six classes: Mammalia, Aves, Amphibia, Pisces, Insecta and Vermes.

1. Mammalia (Mammals) 

Heart with two auricles and two ventricles; warm red blood.
Lungs breathing reciprocally.
Jaw incumbent, covered.
Penis entering in viviparous, lactating.
Senses: tongue, nostrils, touch, eyes, ears.
Covering: hairs, few for the Indic ones, fewest for the aquatic ones.
Support: four feet, except for the aquatic ones, in which the posterior feet coalesced with the tail.

Mammals included 8 orders that were defined mainly on the arrangement of teeth: Primates, Bruta, Ferae, Bestiae, Glires, Pecora, Belluae, and Cete. They are shown below with their respective genera.

1.1 Primates (prime ones), having four parallel upper incisives and solitary tusks: Homo (humans), Simia (all apes and monkeys), Lemur (lemurs), Vespertilio (bats)

Four species listed by Linnaeus under Primates (left to right): human (Homo sapiens), Barbary macaque (Simia sylvanus, now Macaca sylvanus), ring-tailed lemur (Lemur catta) and parti-colored bat (Vespertilio murinus). Credits of the photos to Pawel Ryszawa (macaque), Wikimedia Commons user Permak (lemur), and Markus Nolf (bat).

1.2 Bruta (brutes), absent incisives on either the upper or the lower jaw: Elephas (elephants), Trichechus (manatees), Bradypus (sloths), Myrmecophaga (anteaters), Manis (pangolins)

The order Bruta included (from left to right) the Asian elephant (Elephas maximus), the West Indian manatee (Trichechus manatus), the pale-throated sloth (Bradypus tridactylus), the giant anteater (Myrmecophaga tridactyla) and the Chinese pangolin (Manis pentadactyla). Credits of the photos to Wikimedia Commons user Ji-Ellle (elephant), U. S. Department of the Interior (manatee), Fernando Flores (sloth), Graham Hughes (anteater), and Wikimedia Commons user nachbarnebenan (pangolin).

1.3 Ferae (ferocious beasts) six sharp upper incisives and solitary tusks, sharp claws: Phoca (seals), Canis (dogs, foxes and hyaenas), Felis (cats), Viverra (mongooses, civets and skunks), Mustela (weasels and otters), Ursus (bears, badgers and raccoons).

Linnaeus’ Ferae included (from left to right, top to bottom) the common seal (Phoca vitulina), the wolf (Canis lupus), the domestic cat (Felis catus, now Felis sylvestris catus), the large Indian civet (Viverra zibetha), the European polecat (Mustela putorius) and the grizzly bear (Ursus arctos). Credits to Maximilian Narr (seal), Gunnar Ries (wolf), Michal Osmenda (cat), flickr user tontravel (civet), Peter Trimming (polecat), and Steve Hillebrand (bear).

1.4 Bestiae (beasts) sharp upper teeth of indeterminate number, always more than one tusk on each side: Sus (pigs), Dasypus (armadillos), Erinaceus (hedgehogs), Talpa (moles), Sorex (shrews and moles), Didelphis (opossums)

Some species in the order Bestiae (left to right, top to bottom): wild boar (Sus scrofa), nine-banded armadillo (Dasypus novemcinctus), West-European hedgehog (Erinaceus europaeus), European mole (Talpa europaea), common shrew (Sorex araneus), and common opossum (Didelphis marsupialis). Credits to Henri Bergius (boar), Hans Stieglitz (armadillo), Jörg Hempel (hedgehog), Mick E. Talbot (mole), Agnieszka Kloch (shrew), and Juan Tello (opossum).

1.5 Glires (dormice) two upper and lower incisives, no tusks: Rhinoceros (rhinoceroses), Hystrix (porcupines), Lepus (hares and rabbits), Castor (beavers and desmands), Mus (mice, rats, hamsters, marmots, etc), Sciurus (squirrels)

Six species that Linnaeus classified as Glires (from left to right, top to bottom): Indian rhinoceros (Rhinoceros unicornis), African crested porcupine (Hystrix cristata), mountain hare (Lepus timidus), Eurasian beaver (Castor fiber), house mouse (Mus musculus), red squirrel (Sciurus vulgaris). Credits to Wikimedia Commons user FisherQueen (rhinoceros), Wikimedia Commons user Quartl (porcupine), Alan Wolfe (hare), Klaudiusz Muchowski (beaver), Wikimedia Commons user 4028mdk09 (mouse), and Hernán de Angelis (squirrel).

1.6 Pecora (cattle) many lower incisives, no upper incisives,  bifid hooves and four-chambered stomach: Camelus (camels, llamas), Moschus (musk deer), Cervus (deer and giraffes), Capra (goats and antelope), Ovis (sheep), Bos (cattle)

Among the species that Linnaeus put together as Pecora there are (from left to right, top to bottom) the dromedary camel (Camelus dromedarius), the Siberian musk deer (Moschus moschiferus), the red deer (Cervus elaphus), the domestic goat (Capra hircus, now Capra aegagrus hircus), the domestic sheep (Ovis aries) and the cattle (Bos taurus). Credits to Bjørn Christian Tørrisen (camel), F. Spangenberg (musk deer), Jörg Hempel (deer), Wolfgang Stadut (goat), Wikimedia user Jackhynes (sheep), and Andrew Butko (cattle).

1.7 Belluae (monster beasts), many obtuse incisives: Equus (horses), Hippopotamus (hippopotamuses, tapirs).

The order Belluae included the zebra (Equus zebra) and the hippopotamus (Hippopotamus amphibius). Credits to Trisha M. Shears (zebra) and Wikimedia user Irigi (hippopotamus).

1.8 Cete (sea monsters), cartilaginous teeth, aquatic animals: Monodon (narwhal), Balaena (whales), Physeter (sperm whales), and Delphinus (dolphins)

The order Cete included the following four species (left to right): narwhal (Monodon monoceros), bowhead whale (Balaena mysticetus), sperm whale (Physeter macrocephalus) and common dolphin (Delphinus delphis).

2. Aves (Birds)

Heart with two auricles and two ventricles; warm red blood.
Lungs breathing reciprocally.
Jaw incumbent, nude, extended, toothless.
Penis sub-entering, without scrotum, in oviparous, calcareous crust.
Senses: tongue, nostrils, eyes, ears without auricles.
Covering: incumbent and imbricate feathers.
Support: two feet, two wings.

Birds included 6 orders defined mainly by the shape of the bill: Accipitres, Picae, Anseres, Grallae, Gallinae, and Passeres

2.1 Accipitrae (hawks), having a curved upper jaw with a sharp end: Vultur (vultures and condors), Falco (falcons, eagles, hawks), Strix (owls), Lanius (shrikes, kingbirds, waxwings)

Accipitres included (from left to right) the Andean-condor (Vultur gryphus), the American kestrel (Falco sparverius), the tawny awl (Strix aluco) and the brown shrike (Lanius cristatus). Credits to Linda Tanner (kestrel), flickr user nottsexminer (awl), and Charles Lam (shrike).

2.2 Picae (magpies), knife-shaped bill with a convex dorsum: Psittacus (parrots), Ramphastos (toucans), Buceros (hornbills), Cuculus (cuckoos), Jynx (wrynecks), Picus (woodpeckers), Corvus (crows and ravens), Coracias (rollers and orioles), Sitta (nuthatches), Merops (bee-eaters), Trochilus (hummingbirds), Crotophaga (anis), Gracula (mynas and grackles), Paradisaea (birds-of-paradise), Alcedo (kingfishers), Upupa (hoopoes), Certhia (treecreepers).

The follwing 16 species were all included in the order Picae (left to right, top to bottom): African grey parrot (Psittacus erithacus), white-throated toucan (Ramphastos tucanus), common cuckoo (Cuculus canorus), Eurasian wryneck (Jynx torquilla), green woodpecker (Picus viridis), common raven (Corvus corax), European roller (Coracias garrulus), wood nuthatch (Sitta europaea), European bee-eater (Merops apiaster), red-billed streamertail (Trochilus polytmus), smooth-billed ani (Crotophaga ani), common hill myna (Gracula religiosa), greater bird of paradise (Paradisaea apoda), common kingfisher (Alcedo atthis), Eurasian hoopoe (Upupa epops), and Eurasian treecreeper (Certhia familiaris). Credits to Wikimedia user Fiorellino (parrot), Marie Hale (toucan), Wikimedia user locaguapa (cuckoo), Carles Pastor (wryneck), Hans Jörg Hellwig (woodpecker), Alan Vermon (raven), flickr user Koshy Koshy (roller), Paweł Kuźniar (nuthatch and treecreeper), Pellinger Attila (bee-eater), Charles J. Sharp (streamertail and ani), Wikimedia user Memset (myna), Andrea Lawardi (bird-of-paradise), wikimedia user Joefrei (kingfisher), Arturo Nikolai (hoopoe).

2.3 Anseres (geese), light bill, covered with skin and with a broad end: Anas (ducks, geese and swans), Mergus (merganser), Procellaria (petrels), Diomedea (albatrosses and penguins), Pelecanus (pelicans, cormorants, gannets, boobies and frigatebirds), Phaethon (tropicbirds), Alca (auks), Colymbus (loons and grebes), Larus (gulls), Sterna (terns), Rynchops (skimmers).

Eleven species listed by Linnaeus under Anseres (left to right, top to bottom): mallard (Anas platyrhynchos), common merganser (Mergus merganser), white-chinned petrel (Procellaria aequinoctialis), wandering albatross (Diomedea exulans), great white pelican (Pelecanus onocrotalus), red-billed tropicbird (Phaethon aethereus), razorbill (Alca torda), black-throated diver (Colymbus arcticus, now Gavia arctica), common gull (Larus canus), common tern (Sterna hirundo), and black skimmer (Rynchops niger). Credits to Andreas Trepte (mallard), Dick Daniels (merganser and skimmer), Ron Knight (petrel), JJ Harrison (albatross), Nino Barbieri (pelican), Charles J Sharp (tropicbird), Steve Garvie (diver), and Arne List (gull).

2.4 Grallae (stilts), subcylindrical bill: Phoenicopterus (flamingoes), Platalea (spoonbills), Mycteria (wood stork), Tantalus (the wood stork again!), Ardea (herons, cranes and storks), Recurvirostra (avocets), Scolopax (woodcocks, ibisis, godwitts, etc), Tringa (sandpipers, lapwings and phalaropes), Fulica (coots, moorhens and jacanas), Rallus (rails), Psophia (trumpeters), Haematopus (oystercatchers), Charadrius (plovers), Otis (bustards), Struthio (ostriches, rheas, cassowaries, and dodoes).

Fifteen species that Linnaeus put in the order Grallae (left to right, top to bottom): American flamingo (Phoenicopterus ruber), Eurasian spoonbill (Platalea leucorodia), wood stork (Mycteria americana), the wood stork again (Tantalus localator), grey heron (Ardea cinerea), pied avocet (Recurvirostra avosetta), Eurasian woodcock (Scolopax rusticola), wood sandpiper (Tringa glareola), Eurasian coot (Fulica atra), water rail (Rallus aquaticus), grey-winged trumpeter (Psophia crepitans), Eurasian oystercatcher (Haematopus ostralegus), ringed plover (Charadrius hiaticula), great bustard (Otis tarda), and ostrich (Struthio camelus). Credits to Paul Asman and Jill Lenoble (flamingo), Andreas Trepte (spoonbill and avocet), Dick Daniels (woodstork), JJ Harrison (heron),  Ronald Slabke (woodcock), Wikimedia user Alpsdake (sandpiper), Axel Mauruszat (coot), Pierre Dalous (rail), Robin Chen (trumpeter), Wikimedia user TomCatX (oystercatcher), Wikimedia user Estormiz (plover), Francesco Varonesi (bustard), and Wikimedia user Nicor (ostrich).

2.5 Gallinae (chickens), convex bill with upper jaw bent over the lower jaw: Pavo (peafowl), Meleagris (turkeys), Crax (curassows), Phasianus (pheasants and chickens), Tetrao (grouse, partridges and quails).

Linnaeus’ Gallinae included (from left to right) the Indian peafowl (Pavo cristatus), the turkey (Meleagris gallopavo), the great curassow (Crax rubra), the common pheasant (Phasianus colchicus), and the wood grouse (Tetrao urogallus). Credits to Wikimedia user Appaloosa (peafowl), Arthur Chapman (curassow), Lukasz Lukasik (pheasant), and Wikimedia user Siga (grouse).

2.6 Passeres (sparrows), conic and acuminate bill: Columba (doves and pigeons), Alauda (larks and pipit), Turdus (thrushes, warblers and mockingbirds), Loxia (crossbills, cardinals, bullfinches, etc), Emberiza (buntings), Fringilla (finches, canaries, sparrows, tanagers, etc), Sturnus (starlings), Motacilla (wagtails, redstarts, warblers, wrens, robins, etc), Parus (tits and manakins), Hirundo (swallows and swifts), Caprimulgus (nightjars).

Eleven species considered as belonging to the order Passeres (left to right, top to bottom): wood pigeon (Columba palumbus), skylark (Alauda arvensis), blackbid (Turdus merula), red crossbil (Loxia curvirostra), yellowhammer (Emberiza citrinella), chaffinch (Fringilla coelebs), common starling (Sturnus vulgaris), white wagtail (Motacilla alba), great tit (Parus major), barn swallow (Hirundo rustica), European nightjar (Caprimulgus europaeus). Credits to Nick Fraser (pigeon), Daniel Pettersson (skylark), Andreas Eichler (blackbird), Andreas Trepte (yellowhammer), Wikimedia user Thermos (chaffinch), Pierre Selim (starling), Malene Thyssen (wagtail), flickr user chapmankj75 (tit), Martin Mecnarowski (swallow), and Dûrzan Cîrano (nightjar).

Among the most peculiar things that we can highlight here are:

• Bats were put together with the primates!
• Rhinos were put together with rodents! This happened because Linnaeus based his classification of mammals on their teeth and the front teeth of rhinos resemble somewhat those of rodents.
• Hippos and tapirs were put in the same genus! The South American tapir was called Hippopotamus terrestris!
• Giraffes were classified as deers, and badgers and raccons as bears.
• Several passerine birds, such as the kingbirds, were considered birds of prey (Accipitres).
• Albatrosses and penguins were in the same genus!
• Storks, herons and cranes were all in the same genus too.
• On the other hand, the woodstork appears twice, as two species from different genera!

As one can see, Linnaeus was not so familiar with animals. He was, afterall, a botanist, but he did his best.

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Reference:

Linnaeus, Carl. 1758. Systema Naturae per Regna Tria Nature…

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

Friday Fellow: Kipling’s Acacia Spider

by Piter Kehoma Boll

Spider are famous for being horrible creatures, atrocious predators with terrible venom and creepy webs. But that’s not quite true once you start to know them well, but, anyway, they used to be considered a group of animals composed solely by predators.

That’s not true anymore. In 2008, it has been found that a small jumping spider is predominantly vegetarian! Its name is Bagheera kiplingi, or the Kipling’s Acacia Spider, and it is our newest Friday Fellow.

A male Bagheera kiplingi feeding on a Beltian body. Foto by M. Milton extracted from Meehan et al. (2009).

The Kipling’s Acacia Spider is found in Central America, in Mexico, Costa Rica and Guatemala. It’s a jumping spider (family Salticidae), the most diverse family of spiders.

Living on acacia trees, the Kipling’s Acacia Spider feeds mainly on Beltian bodies, small structures at the tip of the Acacia’s leaflets that are rich in proteins, sugars and fats. The Beltian bodies are a food source for ant species of the genus Pseudomyrmex that live in a mutualistic relationship with the acacias, protecting the trees from herbivores.

Our spider most likely became an oportunist by exploring a resource that was not designed for it. And more than that, sometimes the spider can attack and eat the ants, especially their larvae, so becoming a kind of annoying disturbance to the mutualistic relationship between ant and tree.

However, despite the fact that it also feeds on ant larvae, Bagheera kiplingi has the Beltian bodies as its main food source. Ironically, the name Bagheera comes from Rudyard Kipling’s character Bagheera, which is a black panther. The specific epithet, kiplingi, honors Rudyard Kipling himself.

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References:

Meehan, C. J.; Olson, E. J,; Reudink, M. W.; Kyser, T. K.; Curry, R. L. 2009. Herbivory in a spider through exploitation of an ant-plant mutualism. Currenty Biology, 19(19):R892-R893. DOI: 10.1016/j.cub.2009.08.049

Wikipedia. Bagheera kiplingi. Available at: <https://en.wikipedia.org/wiki/Bagheera_kiplingi&gt;. Access on February 02, 2016.

The tegu lizard and the origin of warm-blooded animals

by Piter Kehoma Boll

Warm blood is the popular way to refer to endothermy, the ability that certain animals have to maintain a high body temperature by the use of heat generated via metabolism, especially in internal organs. Mammals and birds are the only extant groups in which all representatives are endothermic, but some fish also have this feature.

Tunna fish are truly endothermic fish, similar to mammals and birds. Photo by opencage.info**

In order to maintain a high body temperature, endothermic animals need a much higher amount of daily food than ectothermic animals (the ones that rely on environmental sources to adjust their body heat). There must be, therefore, a considerable advantage in endothermy to explain such a increased consumption of resources. The advantages include the ability to remain active in areas of low temperature and an increase in efficienty of enzimatic reactions, muscle contractions and molecular transmission across synapses.

The origin of endothermy is still a matter of debate and several hypothesis have been erected. The main ones are:

1. A migration from ectothermy to inertial homeothermy and finally endothermy.

According to this hypothesis, animals that were initially ectothermic grew in size, becoming inertially homeothermic, i.e., they retained a considerable constant internal body temperature due to the reduced surface area in relation to the their volume. Lately, selective pressures forced those animals to reduce in size, which made them unable to sustain a constant internal temperature and therefore their enzimatic, muscular and synaptic efficiency became threatened. As a result, they were forced to develop an alternative way to maintain a high body temperature and acquired it through endothermy.

Initially considered a plausible explanation due to the body size of the ancestors of mammals in fossil record, new phylogenetic interpretations caused a complete mix of large-bodied and small-bodied animals, so that currently fossils don’t support this idea anymore.

2. A large brain heating the body

The brain in endothermic species produces much more heat than any other organs. This led to the assumption that maybe a large brain generating heat was the responsible for the later development of full endothermy. However, evidence from both exant and extinct species point to the opposite. It seems more reasonable that a large brain evolved after endothermy and not the opposite.

3. A nocturnal life needs more heat

This idea states that the development of endothermy happened as a way to allow animals to be active during the night. The fact that most primitive mammals appear to have been nocturnal seems to support this hypothesis, but in fact many extant nocturnal mammals actually have a lower body temperature than diurnal mammals. Other aspect that counts against this hypothesis is that the ancestors of mammals already showed evidences of an increase in body temperature despite the fact that they most likely were not nocturnal.

4. Heat to help the embryos to develop

As you may know, in many ectothermic vertebrates, such as reptiles, eggs need to be incubated at a constant temperature in order to develop adequately. Endothermy, therefore, could have evolved as a way to allow parents to incubate the eggs themselves and have a higher control on temperature stability. One fact that support this theory is the dual role of thyroid hormones in reproduction and in the control of metabolic rate.

Endothermy may have evolved to incubate eggs at a constant temperature. Photo by Bruce Tuten**

5. Aerobic capicity leading to the heating of internal organs

According to this hypothesis, endothermy evolved after the increase of aerobic capacity, i.e., the first thing to happen was to increase the ability of muscles to consume oxygen in order to release energy, which helped the animal to move faster, among other things. This increased aerobic capicity was attained by increasing the number of mitochondria in muscle cells, which led to higher body temperature in the muscules and consequently a higher visceral temperature. Despite fossils indicating that mammal ancestors developed morphological adaptations indicating increased aerobic capacity, it is not possible to afirm that endothermy was not already present in those species.

Very recently, it has been found that the tegu lizards (Salvator merianae) from South America increase their body temperature during the reproductive season, achieving as much as 10°C above the environment temperature at night. Thus, it seems that they are able to increase heat production and heat conservation in ways similar to the ones used by fully endothermic animals.

The tegu lizard Salvator merianae is a facultative endotherm. Photo by Jami Dwyer.

As such an increase in body temperature happens during the reproductive cycle, it supports the hypothesis of endothermy evolving to assist the development of embryos, as explained above. Also, it indicates that ectotherms may engage in temporary endothermy and perhaps permanent endothermy may have evolved by using this path.

Further studies on the tegu lizards are needed to clarify this interesting phenomenon and expand our knowledge on endothermy evolution in mammals and birds.

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References:

Kemp, T. (2006). The origin of mammalian endothermy: a paradigm for the evolution of complex biological structure Zoological Journal of the Linnean Society, 147 (4), 473-488 DOI: 10.1111/j.1096-3642.2006.00226.x

Tattersall, G., Leite, C., Sanders, C., Cadena, V., Andrade, D., Abe, A., & Milsom, W. (2016). Seasonal reproductive endothermy in tegu lizards Science Advances, 2 (1) DOI: 10.1126/sciadv.1500951

Wikipedia. Endotherm. Available at: <https://en.wikipedia.org/wiki/Endotherm&gt;. Access on February 1, 2016.

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

** 
This work is licensed under a Creative Commons Attribution-ShareAlike 2.5 Generic License.