Die Megascolecidae (von griech. μέγας mégas „groß“ und σκώληξ skṓlēx „Wurm“) sind eine Familie der Crassiclitellata (Regenwürmer im weiteren Sinne) in der Unterklasse der Wenigborster innerhalb des Tierstamms der Ringelwürmer (Annelida). Auf Deutsch werden sie auch Riesenregenwürmer genannt (engl. giant earthworms). Sie sind aber eine andere Familie als die im Deutschen meist als Regenwürmer bezeichneten Lumbricidae. Mit über 1000 Arten sind sie die artenreichste Familie der Crassiclitellata.
Die Riesenregenwürmer (Megascolecidae) haben einen zylindrischen Körper, bei dem dorsale Poren vorhanden sind. In der Regel gibt es an jedem Segment vier Paar Borsten, doch sind in einigen Gattungen wie Pheretima und Amynthas an jedem Segment zahlreiche Borsten vorhanden, deren Anzahl dann oft an den hinteren Segmenten größer ist als an den vorderen. Das Clitellum ist ringförmig oder sattelförmig und nimmt bis zu 7 Segmente zwischen dem 12. und dem 18. Segment ein. Es gibt keine Tubercula pubertatis, doch sind Genitalmarkierungen oder auch Porophoren allgemein vorhanden.
Die Riesenregenwürmer haben 1 bis 3 Kaumägen im Bereich des Oesophagus, jedoch nur selten (bei Pleinogaster) einen im Mitteldarm. Darmblindsäcke sind manchmal, Kalkdrüsen im Darm oft vorhanden. Innerhalb des geschlossenen Blutgefäßsystems verläuft im Vorderabschnitt des Tieres neben dem Rückengefäß über dem Oesophagus auch mindestens ein supra-oesophageales Blutgefäß. Die Nephridien sind wohl (Makronephridien) oder auch nur teilweise (Meronephridien) entwickelt.
Wie alle Gürtelwürmer sind die Riesenregenwürmer Zwitter mit meist zwei Paar Hoden im 10. und 11. Segment (holandrisch), anderenfalls einem Paar Hoden im 10. (protandrisch) oder 11. Segment (metandrisch) sowie dahinter einem Paar Eierstöcke im 13. Segment (metagyn), die ihre Eier über eine unpaare oder ein Paar weiblicher Geschlechtsöffnungen ventral am 14. Segment ins Freie entlassen. Die Spermienleiter queren dagegen mehrere Segmente, darunter das eierstocktragende, und das Paar der männlichen Geschlechtsöffnungen befindet sich hinter der weiblichen bauchseitig am 18., bei Nelloscolex und Tonoscolex am 17., selten (bei wenigen Pheretima-Arten) am 19. oder 20. Segment unmittelbar hinter dem Clitellum. Die Prostatae, generell paarig im 18. Segment, sind traubenförmig ohne Zentralkanal und münden meist gemeinsam mit den Spermienleitern durch die männlichen Geschlechtsöffnungen nach außen, anderenfalls durch Prostataporen im selben Segment wie die männlichen Öffnungen (Plutellus) oder weiter hinten (Nelloscolex und Tonoscolex). Die Receptacula seminis haben meist Blindsäcke und münden in paarigen oder zahlreichen Öffnungen vor den hodentragenden Segmenten nach außen.
Die Megascolecidae leben meist im Boden, teilweise aber auch auf Bäumen oder Sträuchern. Einzelne Arten werden auch im Süßwasser und im Meer gefunden.
Diejenigen Arten, die in trockenen Böden leben, zeigen spezielle physiologische Anpassungen. Zum Beispiel münden bei ihnen die Nephridien (Ausscheidungsorgane) in den Darmtrakt (sogenannte Enteronephridien), was zur Flüssigkeitsersparnis beiträgt. Bei den übrigen Ringelwürmern münden die Nephridien direkt nach außen (Metanephridien).
In Australien werden die Würmer bis über 2 Meter lang (im Extremfall angeblich ca. 3 Meter) und bis mehr als fingerdick (Extremfall ca. 3 Zentimeter), wobei sie ein Gewicht bis etwa 450 Gramm erreichen. Sie sind dort auch eine Touristenattraktion, denen sogar ein eindrückliches Feldmuseum gewidmet ist (Giant Earthworm Museum in Bass, 70 Meilen südöstlich von Melbourne). Manche Arten sind allerdings auch recht klein.
Die Megascolecidae kommen natürlicherweise in Australien, Neuseeland, Afrika, Süd- und Südostasien (z. B. Japan) und auch Amerika vor; das ursprüngliche Verbreitungsgebiet scheint die Südhalbkugel (Gondwana) gewesen zu sein. Sie sind heute teilweise, insbesondere in Australien, ernsthaft bedroht, wobei vermutlich die Verdrängung durch die eingeschleppten europäischen Regenwürmer einen Hauptfaktor darstellt.
Die einzige bisher nachweislich durch menschliche Einwirkung ausgestorbene Regenwurm-Art, der Lake-Pedder-Regenwurm, wurde Opfer eines Staudammprojekts.[1]
Sowohl die Verwandtschaft der Megascolecidae zu den übrigen Wenigborstern (Oligochaeta) als auch die verwandtschaftlichen Zusammenhänge innerhalb der Familie werden derzeit noch kontrovers diskutiert. Morphologische und molekulargenetische Befunde widersprechen sich infolge von Homoplasien an vielen Stellen.[2]
Zu einzelnen Arten siehe:
Derzeit werden aufgrund morphologischer Abgrenzung rund 34 Gattungen unterschieden, die zusammen über 1000 Arten umfassen:
Die Megascolecidae (von griech. μέγας mégas „groß“ und σκώληξ skṓlēx „Wurm“) sind eine Familie der Crassiclitellata (Regenwürmer im weiteren Sinne) in der Unterklasse der Wenigborster innerhalb des Tierstamms der Ringelwürmer (Annelida). Auf Deutsch werden sie auch Riesenregenwürmer genannt (engl. giant earthworms). Sie sind aber eine andere Familie als die im Deutschen meist als Regenwürmer bezeichneten Lumbricidae. Mit über 1000 Arten sind sie die artenreichste Familie der Crassiclitellata.
Мегасколециддер (лат. Megascolecidae) — Австралиядагы сөөлжандардын бир тукуму.
The Megascolecidae is a taxonomic family of earthworms which is native to Madagascar, Australia, New Zealand and both South East Asia and North America. All species of Megascolecidae belong to the Clitellata class.[2] Megascolecidae are a large family of earthworms[3] and they can grow up to 2 meters in length.[4] The intercontinental distribution of Megascolecidae favours the Continental Drift theory.[5]
The feature that distinguished Megascolecidae from other earthworm families is their large size. They are an essential part of maintaining soil structure, minor carbon sequestration, and maintaining terrestrial ecosystem balance. Megascolecidae is one of many families Annelida phylum. They live in a terrestrial environment and have a preference for soil with high biomass content, high humidity, and warm temperature. There are many different genera of Megascolecidae and the total number of species is still in the exploration stage.
Different species of Megascolecidae have different physiological features. However, some familiarities of physiological features can be found between species of Megascolecidae.[6] The megascolecidae family are relatively large individuals. On average, the length of earthworms from megascolecidae varies from 1 centimetre and 2 metres.[4] The number of spermathecal pores are normally paired or multiple can be present in a species of megascolecidae. The location of spermathecal pores and how they are positioned in different segmental locations is used in the identification of different megascolecidae species[7]
Earthworms ingest a variety of organic materials that can be found in the soil since they live in terrestrial environments.[8] Earthworm from species Megascolecidae family has the ability to decompose lignocellulose which requires assistance from microorganisms in their digestive system.[9] Aside from microorganism, other things that can be found in earthworms includes digestive enzymes such as amylase, cellulase and proteins in different region of the gut. The chemical digestion mainly occurs in the intestinal caeca of earthworm, these was higher protease activity than in other parts of the gut.[8]
Genital marking of different species in the Megascolecidae family is part of the distinguishing process between species. Thus, genital marking is a unique feature that differs different species from each other.[10]
Megascolecidae are oviparous since they lay eggs in order to reproduce. They are biparental.[11] The ideal condition of reproduction for megascolecidae is 25 °C where the megascolecidae egg hatch the quickest and has the highest cocoon production.[12]
The male reproductive organ of Megascolecidae includes testes, seminal vesicles, spermathecae, prostate gland[13] and spermathecal pores.[14] The sperm can be found in testes and seminal vesicles however, it can not be found in spermathecae.[11] The female reproductive organ consist of female pore which normally comes in pairs.[10] Both male and female reproductive organs are present in earthworms because they are monoecious. To breed, two earthworms exchange sperm. Long after they are separated, the egg case is secreted. It forms a ring around the worm then, the worm removes the ring from its body and injects their own eggs and the other worm's sperm into it. Afterwards the egg case will be sealed and ready to be incubated to hatch and become a cocoon.[15]
Megascolecidae start their life cycle as an egg that will hatch to be a cocoon and later will grow into a full size earthworm. Their lifecycle takes around 50–57 days in average depending on the external environments and habitat. The rate of growth during the first 14 days is very low however, afterward 21 – 28 days the rate of growth increases and then it will increase and decrease throughout the worm's life with no pattern.[16] The growth rate of Megascolecidae is correlated to the temperature of their environment. As the temperature increased from 30 °C it shows a significant growth rate and decreasing the time to sexual maturity. The ideal living temperature of Megascolecidae is around 15 °C to 30 °C.[17] Overall mean growth of a megascolecidae is 1.79 mg/worm/day, 1.57 mg/worm/day and 1.34 mg/worm/day depending on the abundance of worm and size of the environment condition.[16]
Hatching process of Megascolecidae eggs is depending on the temperature of the environment. The incubation during hatching process would decrease in warmer temperature and increase in colder temperature. Due to that, the cocoon production of Megascolecidae is correlated with the temperature of the environment[18]
Different species of Megascolecidae can be found different parts of the world such as Australia, New Zealand, Asia, North America, South America and Europe.[19] The intercontinental presence of Megascolecidae species can be explained through The Permanence of Continent Theory. This theory provides the explanation of most Cenozoic distributions however, this theory does not explain the presence of European Megascolecidae in North America. The intercontinental distribution of Megascolecidae has two different theories that explains its phenomenon: 1) land bridges and 2) continental drift.[5]
The Megascolecidae family are originally native to Australia.[20] In Australia, there are is number of Megascolecidae species that can be found native in different parts of the country. Anisochaeta sebastiani is an example of species that belongs to Megascolecidae. This species can be found in different parts of Australia from Queensland to Tasmania.[21] There are 53 known species of earthworms that belong Megascolecidae family that can be found in Western Australia. Graliophilus georgei and Graliophilus secundus are some examples of Megascolecidae family that can be found in Western Australia. They belong to the genus Graliophilus.[22] Another species from Graliophilus genus called Graliophilus zeilensis can be found in the Northern Territory specifically, in Mount Zeil, West MacDonnell Ranges. Graliophilus zeilensis can be found on the highest point of the mountain where average rainfall of the region is 250 mm annually. This distinguish them from other species from Graliophilus family because it is below the favourable habitat to support native earthworms.[23] Metaphire and Amynthas are two common genus belonging to Megascolecidae family. This genus can be found in different countries in Asia.[24]
There are eight different species of genus Metaphire that can be found in Malaysia; Metaphire sedimensis, Metaphire hijaunensis, Metaphire songkhlaensis, Metaphire pulauensis, Metaphire pulauensis, Metaphire fovella, Metaphire balingensis, and Metaphire strellana. The commonality between the habitat of these species are that they are found in soil containing medium to high organic material such as loamy soil[25]
In Indonesia, there are nine different genera that can be found throughout the country; Amynthas, Archipheretima, Metaphire, Metapheretima, Pheretima, Pithemera, Planapheretima, Pleinogaster and Polypheretima. Each of these genus can be found in every single continents in Indonesia. Pheretimoid is the biggest group of genera which is consisting of 65 and 38 Species respectively. Some infra-generic groups are restricted to the mainland of Asia, however, others are native to Indo-Australian Archipelago.[26]
The ideal habitat for Megascolecidae is consisting of terrestrial environment with soil that has high content of organic material such as; loamy soil,[16] cattle solids, pig solids and aerobically digested sewage sludge.[12] Megascolecidae grows and produces more cocoons during the summer months comparing to the winter months. This is because their life cycle is highly correlated to the temperature and humidity of the environment.[16] They prefer to grow in highly humid and warm temperature areas which is their ideal habitat. However, some Megascolecidae species have adapted to colder temperatures and drier areas which enables them to live in higher regions of the land.[23]
Megascolecidae can be found in terrestrial environment.[8] They are an important part of the soil ecosystem in that they indicate soil health and maintain soil productivity. The abundance of earthworms is highly correlated to soil pH, texture, water content, and temperature.[27] Earthworm has the ability to bio-monitoring soil pollutants.[28] This is because of earthworm's burrowing habit that serves as a facilitation of preferred water flow and agrochemical through the soil profile thus, earthworms are able to perform carbon sequestration and reducing soil pollutants.[27] Invasive earthworms can have a significant impact causing changes in soil profiles, nutrient and organic matter content and other soil organisms or plant communities. In most cases the disturbed areas includes agricultural systems or previously areas that are lacking of earthworms would see the biggest impact of the invasive earthworms.[29] The impact of earthworm towards soil structure is cause by the rate of net nitrogen mineralization.[30]
The Megascolecidae is a taxonomic family of earthworms which is native to Madagascar, Australia, New Zealand and both South East Asia and North America. All species of Megascolecidae belong to the Clitellata class. Megascolecidae are a large family of earthworms and they can grow up to 2 meters in length. The intercontinental distribution of Megascolecidae favours the Continental Drift theory.
The feature that distinguished Megascolecidae from other earthworm families is their large size. They are an essential part of maintaining soil structure, minor carbon sequestration, and maintaining terrestrial ecosystem balance. Megascolecidae is one of many families Annelida phylum. They live in a terrestrial environment and have a preference for soil with high biomass content, high humidity, and warm temperature. There are many different genera of Megascolecidae and the total number of species is still in the exploration stage.
Las lombrices gigantes (Megascolecidae) son un grupo de lombrices terrestres que tiene representantes nativos en Australia, Nueva Zelanda, sudeste y este de Asia, y América del Norte. Los linajes más antiguos de la familia muestran una distribución de Gondwana y se han utilizado como evidencia de la deriva continental. Miembros del género Amynthas por ejemplo, están ampliamente distribuidos en los trópicos, y al igual que las lombrices de tierra (Lumbricidae) se distribuyen en zonas templadas.[1]
Se caracterizan por tener una típica disposición "megascolécida" de los poros masculinos, con conductos deferentes y prostáticos unidos antes de abrirse a través de un poro en el segmento 18. Además tienen múltiples o al menos dos nefridios por segmento. Algunos taxones presentan nefridios que en lugar de vaciarse en la superficie del cuerpo, se vacían en el tracto digestivo.
Son de gran tamaño; algunas especies alcanzan el metro de longitud. La más grande conocida fue un ejemplar de la lombriz gigante de Gippsland, Australia (Megascolides) que alcanzó 3.7 m.[2]
Las lombrices gigantes (Megascolecidae) son un grupo de lombrices terrestres que tiene representantes nativos en Australia, Nueva Zelanda, sudeste y este de Asia, y América del Norte. Los linajes más antiguos de la familia muestran una distribución de Gondwana y se han utilizado como evidencia de la deriva continental. Miembros del género Amynthas por ejemplo, están ampliamente distribuidos en los trópicos, y al igual que las lombrices de tierra (Lumbricidae) se distribuyen en zonas templadas.
Se caracterizan por tener una típica disposición "megascolécida" de los poros masculinos, con conductos deferentes y prostáticos unidos antes de abrirse a través de un poro en el segmento 18. Además tienen múltiples o al menos dos nefridios por segmento. Algunos taxones presentan nefridios que en lugar de vaciarse en la superficie del cuerpo, se vacían en el tracto digestivo.
Son de gran tamaño; algunas especies alcanzan el metro de longitud. La más grande conocida fue un ejemplar de la lombriz gigante de Gippsland, Australia (Megascolides) que alcanzó 3.7 m.
Megascolecidae on heimo Haplotaxida-lahkossa. Heimoon kuuluu Megascolides australis, maailman suurin maamato.
Megascolecidae on heimo Haplotaxida-lahkossa. Heimoon kuuluu Megascolides australis, maailman suurin maamato.
Tämä eläimiin liittyvä artikkeli on tynkä. Voit auttaa Wikipediaa laajentamalla artikkelia.Les Megascolecidae sont une famille de vers de terre.
Selon BioLib (29 déc. 2020)[1] :
Les Megascolecidae sont une famille de vers de terre.
I Megascolecidae sono una famiglia di lombrichi.
La famiglia ha rappresentanti nativi di Australia, Nuova Zelanda, Asia sud-orientale e orientale e Nord America. I lignaggi più antichi della famiglia mostrano una distribuzione gondwana e sono stati usati come prova della deriva dei continenti. Membri del genere Pheretima (p.e. Amynthas) sono ampiamente distribuiti intorno ai Tropici, così come alcuni Lumbricidae sono distribuiti nelle zone temperate. Appartengono a questa famiglia anche alcuni generi nativi del Nord America, per esempio Arctiostrotus, Argilophilus e Driloleirus.
I membri di questa famiglia hanno la tipica disposizione "megascolecina" dei pori maschili, con i vasi deferenti e i dotti prostatici che si uniscono prima di aprirsi attraverso un poro combinato sul segmento 18, piuttosto che la disposizione "acantodrilina" (con pori maschili e pori da una o più coppie di prostate che si aprono separatamente vicino al segmento 18, ma mai combinate sul segmento 18) come si trovano nelle famiglie correlate Acanthodrilidae, Octochaetidae ed Exxidae.
I Megascolecidae sono meroici, con più nefridi per segmento, o hanno la disposizione oloica plesiomorfa di due nefridi per segmento. Alcuni taxa mostrano anche enteronefria, allorché alcuni nefridi, invece di svuotarsi sulla superficie corporea, si svuotano nel tratto digerente. Le setae possono essere lumbricine (plesiomorfe, otto per segmento) o perichaetine (più di otto setae per segmento).
La famiglia contiene i seguenti generi:
Megascolecidae é uma grande família de minhocas, com distribuição na Austrália, Nova Zelândia, sudeste e leste da Ásia e na América do Norte.[1] Os membros da família apresentam terminalia masculina de tipo megascolecina, ao contrário das famílias Acanthodrilidae, Octochaetidae e Exxidae, que apresentam terminalia masculina de tipo acantodrilina.
Membros do grupo Pheretima (e.g. Amynthas) apresentam uma distribuição alargada, em torno dos trópicos. Os géneros nativos da América do Norte Argilophilus, Driloleirus e Arctiostrotus, pertencem a esta família.
Primitive members of the family show a Gondwanan distribution and have been used as evidence of continental drift
Muitos dos géneros apresentam nefrídeos com uma disposição menos primitiva, com vários nefrídeos por segmento. Alguns taxa apresentam enteronefria, isto é, os nefrídeos vão dar ao trato digestivo.
lista incompleta
Megascolecidae é uma grande família de minhocas, com distribuição na Austrália, Nova Zelândia, sudeste e leste da Ásia e na América do Norte. Os membros da família apresentam terminalia masculina de tipo megascolecina, ao contrário das famílias Acanthodrilidae, Octochaetidae e Exxidae, que apresentam terminalia masculina de tipo acantodrilina.
Membros do grupo Pheretima (e.g. Amynthas) apresentam uma distribuição alargada, em torno dos trópicos. Os géneros nativos da América do Norte Argilophilus, Driloleirus e Arctiostrotus, pertencem a esta família.
Primitive members of the family show a Gondwanan distribution and have been used as evidence of continental drift
Muitos dos géneros apresentam nefrídeos com uma disposição menos primitiva, com vários nefrídeos por segmento. Alguns taxa apresentam enteronefria, isto é, os nefrídeos vão dar ao trato digestivo.
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