Megascolex caeruleus
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| Templeton , 1844 |
Megascolex caeruleus (common synonym Megascolex coeruleus ) is the name of a type of little bristle from the family of Megascolecidae (giantearthworms) in the order of Crassiclitellata (earthworms in the broader sense), which is common in Sri Lanka and reaches a length of about one meter.
features
Megascolex caeruleus has a cylindrical body and is about 80 cm to 1 m long and 2.5 cm to 3 cm wide, with adult animals having about 270 segments. The often shiny blue color is noticeable, whereby parts such as the head lobe that are well supplied with blood can be colored red by the hemoglobin-containing blood . The segments can turn orange-yellow to the side and completely yellow on the ventral side. There are numerous bristles on each segment , the number of which is around 140 on the posterior segments, but only 36 on the 5th segment. From the furrow between the 6th and 7th segment, dorsal pores are located in the furrows on the back.
The coelom spaces are septated from the transition from the 4th to the 5th segment, with the septa between the 8th and 13th segment being thickened. The intestinal canal has a chewing stomach in the 5th segment and calcic glands from the 10th to the 15th segment. The midgut begins in the 17th segment and has a number of midgut glands from the 112th to the 133rd segment.
The back vessel of the closed blood vessel system is supplemented in the front part of the body by an additional supraintestinal vessel. In the segments from the 6th to the 13th segment there are 8 pairs of hearts , of which the first three in the 6th and 7th segment as lateral hearts connect the dorsal vessel with capillaries of the masticatory stomach, the lateral heart in the 8th segment connect the dorsal vessel directly to the abdominal vessel, The following five from the 9th to the 13th segment, on the other hand, are connected as laterointestinal hearts to the dorsal and supraintestinal vessels and supply both the capillary system of the intestine and the body wall.
The bristle clitellum is saddle-shaped at the back and extends from the 13th to the 21st segment. Like all girdle worms , the giant earthworm is a hermaphrodite whose unpaired female genitals are located on the abdomen on the 14th segment and whose pair of male genitals are located between the abdominal bristles of the 18th segment. On the 18th segment, there are also two papillae where small white glands open outwards. The 2 pairs of receptacula seminis are located in the 8th and 9th segment and each has a small blind sac. The sperm conductors have small and compact glands.
Distribution, habitat and way of life
Megascolex coeruleus is common in the lowland rainforests on the island of Sri Lanka . Like other crassiclitellates , it is a substrate eater , digesting the organic components of the swallowed soil.
Surname
In 1844 Robert Templeton chose the Greek generic name Megascolex (μεγασκώληξ) "big worm" ( ancient Greek μέγας mégas "big" and σκώληξ skṓlēx "worm") and the Latin epithet caeruleus "sky blue". Alfred Gibbs Bourne used the spelling Megascolex cœruleus in 1891 , but referred explicitly to Templeton. The naming of " Megascolex caeruleus Templeton 1844 " and " Megascolex coeruleus Bourne 1891 " as in ITIS as two separate valid species descriptions is therefore incorrect.
literature
- Robert Templeton (1844): Description of Megascolex caeruleus. Proceedings of Zoological Society London 12, pp. 89-91.
- Robert Temple [sic] (1844): About the Megascolex caeruleus. In: Ludwig-Friedrich von Froriep (Hrsg.): Notes from the field of nature and medicine, collected a. communicated by Ludwig Friedrich v (on) Froriep, Volume 84. Lossius, Weimar 1845, pp. 182f.
- Alfred Gibbs Bourne (1891): On Megascolex coeruleus, Templeton, from Ceylon; together with a Theory of the Course of the Blood in Earthworms. Journal of Microscopical Science 32, pp. 49-87.
- Samrendra Singh Thakur, Shweta Yadav (2018): Exploration of Earthworms of India through Online Digital Library. Provisional chapter. P. 43, 5.5.5. Megascolex Beddard, 1895. doi : 10.5772 / intechopen.75666