Some time ago I introduced a cool unicellular alga, the Sailor’s Eyeball, which can reach about 5 cm in diameter, being one of the largest unicellular organisms known to exist.
Today we’ll know one more creature of this type, only it is not an alga, but a testate amoeba more closely related to foraminifers. Named Gromia sphaerica, I will here call it the giant gromia.
Specimens of the giant gromia from the Bahamas. Image extracted from Matz et al. (2008).
The giant gromia was first found in the Arabian Sea at depths of more than 1100 m and was formally described in 2000. It lives lying on the substrate and is usually covered by a thin layer of sediment, appearing as small spheres scattered across the sea floor. The body is spherical or grape-shaped but hollow, with the interior filled with fecal material (called stercomata) or other fluids. This spherical cell is covered by a shell, or test, of organic material which shows several small perforations by which thin expansions of the cytoplasm, forming a kind of pseudopod, can be extended. The size of the test can reach up to 3 cm in diameter, being much larger than that of its best known relative, Gromia oviformis.
Several specimens of Gromia sphaerica on the sea floor of the Bahamas with the tracks left by their movement. Extracted from Matz et al. (2008).
In 2008, another population of species was found in the waters around the Bahamas. Specimens there are not as spherical as in the population in the Arabican Sea and were seen associated with tracks that indicate that these organisms slowly move across the sediment. The tracks clearly resemble some fossil tracks from the Pre-Cambrian period, which are usually considered an indication of the early evolution of multicellular animals. However, this discovery of unicellular organisms being able to produce tracks similar to those associated with animals raises doubt about the time of origin of multicellular animals.
In a series of previous posts, I detailed the classification of living beings by Linnaeus in his work Systema Naturae as presented in its 10th edition, published in 1758. Here, I will present it in a summarized way and show changes that happened from the 10th edition to the 13th edition published in two parts, one 9 years later in 1767, dealing with animals, and one 12 years later, in 1770, dealing with plants.
Linnaeus classified animals in 6 classes: Mammalia, Aves, Amphibia, Pisces, Insecta and Vermes.
1. Mammalia included mammals and in 1758 they were classified in 8 orders: Primates, Bruta, Ferae, Bestiae, Glires, Pecora, Belluae, Cete (see details here).
In 1767 the order Bestiae no longer exists. Armadillos (Dasypus) were transfered to Bruta, pigs (Sus) to Belluae and the remaining genera to Ferae. Additionally, rhinoceroses (Rhinoceros) were transfered from Glires to Belluae and one bat species was transferred from the genus Vespertilio in Primates to a new genus, Noctilio, in Glires.
2. Aves included birds and in 1758 they were classified in 6 orders: Accipitrae, Picae, Anseres, Grallae, Gallinae, Passeres (see details here).
In 1767, five new genera are seen in Picae: Buphaga, the oxpeckers, Trogon, the trogons, and Oriolus, the orioles (previously in the genus Coracias), Bucco, the puffbirds and Todus, the todies. One new genus appears in Anseres, Plotus, the darters. The order Grallae receives the new genera Palamedea, the seriemas and screamers, Parra, the jacanas, and Cancroma, the boat-billed heron. The order Gallinae is increased with the new genera Didus, the dodo (which was previously a member of the genus Struthio in the order Grallae), and Numida, the guineafowl (previously in the genus Phasianus). And, finally, the order Passeres received the new genera Pipra for the manakins (previously in Parus), Ampelis, the waxwings and cotings (previously in the genus Lanius in the order Accipitrae), Tanagra, the tanagers (previously in Fringilla) and Muscicapa, the flycatchers (previously in the genera Corvus and Motacilla).
It is also interesting to notice a change in the name of the order Accipitrae to Accipitres, and the genus Jynx is here written Yunx.
3. Amphibia included reptiles, amphibians and some fish and had 3 orders: Reptiles, Serpentes and Nantes (see details here).
The orders Reptiles and Serpentes remained the same. The order Nantes, which in 1758 included mainly cartilaginous fishes, in 1767 included a lot of genera that were previously classified in the class Pisces, especially in the order Branchiostegi (see below).
4. Pisces included most fish and had 5 orders: Apodes, Jugulares, Thoracici, Abdominales and Branchiostegi (see details here).
The genus Ophidion was transfered from the order Jugulares to Apodes and appears spelled Ophidium. The order Thoracici received the additional genus Cepola (red bandfishes) and the order Abdominales was increased with the genera Amia (the bowfin), Teuthis and Elops (the ladyfish), as well as the genus Mormyrus, previosly in the order Branchiostegi, which ceased to exist.
5. Insecta included arthropods and had 7 orders: Coleoptera, Hemiptera, Lepidoptera, Neuroptera, Hymenoptera, Diptera, Aptera (see details here).
The order Coleoptera received the new genera Lucanus (stag beetles, previously in Scarabaeus), Byrrhus (pill beetles), Gyrinus (whirligig beetles), Bruchus (pea weevils), Ptinus (spider beetles), Hispa, Lampyris (glowworms). The genera Blatta and Gryllus were transfered to Hemiptera and mantises were removed from Gryllus and received their own genus, Mantis. Additionally, the lantern flies were removed from the genus Cicada and transferred to Fulgora. In the order Neuroptera, antlions were removed from the genus Hemerobius and transferred to a new genus Myrmeleon. In the order Hymenoptera, the cuckoo wasps were transferred from the genus Sphex to a new genus Chrysis.
6. Vermes included several worms, molluscs, echinoderms, cnidarians and hagfishes. There were 5 orders: Intestina, Mollusca, Testacea, Lithophyta and Zoophyta (see details here).
From 1758 to 1767, the genus Furia, of a fictional species, was transferred from Intestina to Zoophyta, and the genus Teredo (shipworms) was transferred from Intestina to Testacea. A new genus, Sipunculus, was added to Intestina to include the peanut worms. In the order Mollusca, we find now the new genera Ascidia (sea squirts), Aplysia (sea hares), Terebella (some polychaetes, previously in Nereis) and Clio (some sea slugs). The genus Priapus, containing sea anemones, is now called Actinia. The order Testacea received the new genera Mactra (trough shells, previously in Cardium) and Sabella (fanworm, previously in Serpula). The order Lithophyta received the new genus Cellepora (for bryozoans). In the order Zoophyta we find the new genera Flustra (for bryozoans previously in Eschara), Vorticella (for ciliates previously in Hydra) and Chaos (for amoebas, previously in Volvox). An additional genus is seen in Zoophyta: Spongia (sponges), transferred from Algae, back in the plant kingdom
Plants had a much more complicated system than animals. There were the plants with regular flowers classified in classes and orders according to the number of male and female sexual organs, respectively (as you can read in detail in parts 1, 2, 3 and 4 of plants in Systema Naturae). Little has changed that except for some genera, as you can see in the table below.
In the class Syngenesia we can notice that the order Polygamia Superflua ceases to exist, with most of its species being transferred to Polygamia Aequalis, and a new order, Polygamia Segregata, is now present. In the class Gynandria a new order, Dodecandria, is created. See those two classes in more detail here.
Linnaeus’ order Filices included (from left to right, top to bottom) the common horsetail (Equisetum arvense), the sensitive fern (Onoclea sensibilis), the common adder’s tongue (Ophioglossum vulgatum), common royal fern (Osmunda regalis), golden leather-fern (Acrostichum aureum), Chinese brake (Pteris vittata), western hard fern (Blechnum occidentale), black spleenwort (Asplenium adiantum-nigrum), common polypody (Polypodium vulgare), Venus-hair fern (Adiantum capillus-veneris), lace fern (Trichomanes chinensis, now Sphenomeris chinensis), European water clover (Marsilea quadrifolia), common pillwort (Pilularia globulifera), and lake quillwort (Isoetes lacustris). Credits to Rob Hille (horsetail), Kurt Stueber (royal fern), Krzysztof Ziarnek (hard fern), Forest & Kim Starr (spleenwort, lace fern), H. Zell (polypody), Tato Grasso (Venus-hair fern), Daria Inozemtseva (quillwort), Wikimedia users JMK (brake), Keisotyo (water clover) and Kembangraps (pillwort), flickr user peganum (sensitive fern).
Among the species in the order Musci there were (from left to right, top to bottom) the common club moss (Lycopodium clavatum), pinnate scalewort (Porella pinnata), prairie sphagnum (Sphagnum palustre), common fountain moss (Fontinalis antipyretica), common bug moss (Buxbaumia aphylla), Alpine haircap (Polytrichum alpinum), horn calcareous moss (Mnium hornum), silver moss (Bryum argenteum), cypress moss (Hypnum cupressiforme). Credits to Christian Fischer (club moss), Rafael Medina (scalewort), Bern Haynold (sphagnum), Hermann Schachner (haircap, silver moss), Bernard Dupont (calcareous moss), and Wikimedia users AnRo0002 (fountain moss) and Aconcagua (cypress moss).
The diverse order Algae included (from left to right, top to bottom) the forest leafy liverwort (Jungermannia nemorea, now Scapania nemorea), common targionia (Targionia hypophylla), green tongue liverwort (Marchantia polymorpha), blasia (Blasia pusilla), floating crystalwort (Riccia fluitans), smooth horwort (Anthoceros laevis, now Phaeoceros laevis), map lichen (Lichen geographicus, now Rhizocarpon geographicum), common stonewort (Chara vulgaris), witch’s jelly (Tremella nostoc, now Nostoc commune), serrated wrack (Fucus serratus), common sea lettuce (Ulva lactuca), rock weed (Conferva rupestris, now Cladophora rupestris), golden wool (Byssus aurea, now Trentepohlia aurea), bath sponge (Spongia officinalis). Credits to Bernd Haynold (leafy liverwort, blasia), Luis Fernández García (targionia), Denis Barthel (green tongue), Christian Fischer (crystalwort), Fritz Geller-Grimm (lichen), Lairich Rig (witch’s jelly), Kristian Peters (sea lettuce), Bioimages (rock wed), JK Johnson (golden wool), Guido Picchetti (sponge) and Wikimedia users Oliver s. (hornwort), Mnolf (stonewort) and Citron (wrack).
The order Fungi contained (from left to right, top to bottom) the field mushroom (Agaricus campestris), common red shelf-mushroom (Boletus sanguineus, now Pycnoporus sanguineus), sweet tooth (Hydnum repandum), common stinkhorn (Phallus impudicus), carnival candy slime-mold (Clathrus denudatus, now Arcyria denudata), vinegar cup (Peziza acetabulum, now Helvella acetabulum), sweet club-mushroom (Clavaria pistillaris, now Clavariadelphus pistillaris), grassland puffball (Lycoperdon cervinum, now Lycoperdon lividum), common pin-mold (Mucor mucedo). Credits to Nathan Wilson (field mushroom), Instituto Últimos Refúgios (shelf mushroom), H. Krisp (sweet tooth, vinegar cup), Jörg Hempel (stinkhorn), Bea Leiderman (slime mold), Francisco J. Díez Martín (club mushroom), Michel Beeckman (puffball) and James Lindsey (pin mold).
Here we can see that Linnaeus’ mess reached its limit. There are even animals classified as plants, as you can see sponges appearing as algae. Actually, the order Algae included species belonging to almost every currently recognized kingdom, from bacteria to animals, fungi, plants and heterokonts. The other orders are considerably more uniform.
We finished Linnaeus’ System! Yay!
I will make an additional post with a summary and then we can move on to changes that happened in following systems. See you there!
– – –
Linnaeus, C. (1758) Systema Naturae per regna tria Naturae…
Velvet worms form an intriguing group of animals that are the sister group of arthropods and also the only animal phylum with only terrestrial species, although aquatic species are known from fossil records.
Today I decided to bring one velvet worm species to be our fellow. Scientifically known as Euperipatoides rowelli, I decided to give it the common name Rowell’s velvet worm.
A specimen of the Rowell’s velvet worm in the lab. Photo by Alan Couch.*
The Rowell’s velvet worm is found in south-east Australia inhabiting humid, temperate forests. They are small animals, with about 5 cm in lenght, and live in decaying wood, dwelling in crevices and feeding on small invertebrates, such as termites and crickets.
Logs are usually inhabited by groups of several individuals that live in a sort of social relationship and are composed of females, males and juveniles, with females being larger and occurring in larger numbers than males. A sort of hierarchical organization also seems to occur, with one female being dominant and followed in dominance by other females, with males and juveniles occupying the bottom of the pyramid. Prey capture often happens in group, and after a prey is subdued, the dominant female will eat first and only after being satiated she will allow other females to eat. Males and juveniles eat the remains left by the females.
New logs are colonized by wandering males. Those release feromones that attract more males and later females. Thus, newly colonized logs have a male-biased aggregation, but the number of females later surpasses that of males. It has been suggested that the initial aggregation of males helps them to attract females due to the increased concentration of feromones.
During reproduction, the male places spermatophores on the skin of the female, With the aid of the female blood cells, the body wall below the spermatophore is breeched and the sperm is released in the female’s body cavity, where it swims to the female reproductive tract.
Due to its abundance in south-east Australia, the Rowell’s velvet worm is an easily obtained species and is slowly becoming one more interesting model organism.
You probably know the common sage, Salvia officinalis, used as an aromatic herb in culinary, but today I’ll talk about one of its crazy cousins, Salvia divinorum, known as the sage of the diviners or seer’s sage.
Endemic to the Sierra Mazateca in the state of Oaxaca, Mexico, where it grows in cloud forests, the sage of the diviners is a herb that reaches about 1 m in height with large yellowish green leaves. The flowers, which are rarely produced, are typical of the family Lamiaceae, to which it belongs, and have purple sepals and white petals.
Inflorescence of the sage of the diviners. Photo by Eric Hunt.*
In its native habitat, the sage of the diviners is used by the Mazatec people to faciliate shamanic visions due to its hallucinogenic properties. The hallucinogen is called salvorin A and is a diterpenoid, although its physiological function resembles more that of opioids. With acive doses as low as 200 µg, salvorin A is the most potent hallucinogen known to naturally occur.
A bowl with a concentrated extract of dry Salvia divinorum. Photo by Wikimedia user Coaster420.
The traditional form of consumption of the leaves of the sage of the diviners is by chewing fresh leaves or by crushing laves and mixing the resulting extract with water to drink it. Smoking the dry leaves is a modern alternative, as currently the drug is becoming more and more popular around the world.
Due to the still modest consumption compared to other hallucinogens, the sage of the diviners is not well covered by legislation worlwide. Some countries consider its use legal, others made it illegal, but many do not have anything concerning its use.
It is time to go back to the micoscopical world and present the wonders that it contains. Today the chosen species is Funneliformis mosseae, which, as always, lacks a common name. I, therefore, decided to call it the versatile funnel glomus.
The versatile funnel glomus is a fungus of the division Glomeromycota. These fungi are characterized by forming an endosymbiotic relationship with plants through structures called arbuscular mycorrhizas, or AMs for short. This special kind of mycorrhiza is formed with the fungus growing inside the tissues and cells of plant roots. It is known that around 80% of all vascular plant families contain AMs.
Spores of the versatile funnel glomus on tomato roots. Photo by Wikimedia user Samson90.
Our species, the versatile funnel glomus, is considered one of the most common fungi associated to plant roots. Found worldwide, it can form AMs with many different plants, including many important cultivars, such as maize, onion, tomato and many others.
A single spore of the versatile funnel glomus showing the funnel-shaped base to the right. Photo extracted from Schüßler & Walker (2010).
Since the versatile funnel glomus lives inside the root tissues and cells, it is not usually conspicuous, but it can be easily identified through its spores, which are about 0.2 mm in diameter and grouped inside sporocarps. The base of the spore has a funnel shape, this being the reason for the name Funneliformis.
The association of the versatile funnel glomus with plants increases nutrient uptake by plants and can also help them cope with environments contaminated with heavy metals, such as lead, by absorbing part of the contaminant, thus reducing its deleterious effect on the plants.
Last week I introduced the small wood cricket, so I will use it as an oportunity to introduce, today, one of its parasites, the Wood Cricket’s Worm Paragordius tricuspidatus.
Two individuals of the wood cricket’s worm. Photo by D. Andreas Schmidt-Rhaesa.*
The wood cricket’s worm is a member of the phylum Nematomorpha, commonly known as horsehair worms. The adults are free-living worms that inhabit freshwater bodies, especially rivers and streams and have a peculiar mating behavior in which many worms are “tied” to each other in a large knot, like a worm orgy. After mating is finished, the female lays its eggs at the edge of the water, on the ground, where they may eventually be ingested by wood crickets living nearby.
Inside the cricket, the egg hatches and the larvae starts to develop inside the cricket’s body cavity, filling it completely during its development. When the worm is ready to leave its host, it is able to control the host’s behavior, inducing it to jump into a water body, allowing the parasite to leave the cricket and go looking for a partner to mate, starting the cycle again.
Paragordius tricuspidatus (arrow) leaving the body of a wood cricket. Photo extracted from Ponton et al. (2006) (See references).
An interesting behavior of the wood cricket’s worm is its ability to escape from the body of a predator. Usually when a wood cricket jumps into the water and the worm is trying to leave the host, an aquatic predator, such as a fish or a frog, may end up eating the cricket, which would put an end to the life of the parasitic worm as well. Recently, however, it has been found that the worm is able to escape the predator’s body, usually through the mouth, when the cricket is eaten. This is the first known case of a parasite escaping a predator of its hosts.
We have to accept that parasitic worms have very adventurous lives.