Poecilotheria subfusca

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Poecilotheria subfusca
Poecilotheria subfusca, 2 cm young animal (♀)

Poecilotheria subfusca , 2 cm young animal (♀)

Systematics
Order : Spiders (Araneae)
Subordination : Tarantulas (Mygalomorphae)
Family : Tarantulas (Theraphosidae)
Subfamily : Poecilotheriinae
Genre : Poecilotheria
Type : Poecilotheria subfusca
Scientific name
Poecilotheria subfusca
Pocock , 1895

Poecilotheria subfusca ( Syn . : Poecilotheria bara , Poecilotheria uniformis ) lives mainly in the cool cloud and cloud forests in the mountains of Sri Lanka and belongs to the tarantula genus Poecilotheria . The species is a relatively variable group of species or forms. The tarantulas, like some other species, are locally called "Divimakulawa" or "Diamakulu". The type of epithet “subfusca” is made up of the Latin prefix “sub” (= below ). and the adjective "fusca" (= dark, dark brown ). together.

distribution and habitat

Poecilotheria subfusca occurs in the central plateau of Sri Lanka between 270 and over 2000 meters above sea level. There she inhabits the tropical, monsoon-dominated , evergreen rainforests , which flow into cooler mountain rainforests and cloud forests from an altitude of about 1000 meters. The distribution area is characterized by a tropical, axeric climate (a rainy season and a dry season ) with only slight temperature fluctuations in the annual mean . The temperatures vary extremely during the day. Temperatures rise to approx. 25 ° C during lunchtime and often drop to 10 ° C at night due to the altitude. In the lower elevations of the plateau, the temperatures fluctuate significantly less. The annual precipitation is between 2500 and 5000 mm, depending on the altitude and location.

The expansive trees of the tropical rainforests form stands 20 to 25 meters high. The canopy is dominated in places by particularly large trees, so-called overhangs. The habitat of Poecilotheria subfusca does not overlap with any other Poecilotheria species. Due to the intensive agriculture (tea plantations, potato and cinnamon cultivation) in the rainy plateau of Sri Lanka, the rainforests have been deforested or have been degraded to secondary forests for 150 years . A certain proportion of the remaining mountain and cloud forests have meanwhile been placed under state conservation. In addition, temperature increases as a result of global warming could disrupt the ecosystem of cool mountain and cloud forests.

features

The females reach a greater body length (starting from the bite claws to the spinnerets) than the males. These are relatively more delicate and long-legged than the female animals and lose their high-contrast youthful coloration almost completely at the latest after moulting ( sexual dimorphism ). The mature males have a mostly dark brown basic color. The yellow drawing elements of the leaf drawing (folium) and on the carapace remain, however.

In Poecilotheria subfusca Pocock, 1895 there was a Vogelspinnenart that occurs with at least two different color forms, and both also have been described separately from each other scientific. Mainly in these forms the females differ from each other. These color forms are different populations that occur at different heights in the Sri Lankan plateau. Whether these are subspecies or even different species does not seem to be fully clear, as the lowland form was sometimes referred to in reputable publications even after the synonymization as Poecilotheria bara Chamberlin , 1917 or sometimes still is. In terraristics , the two color forms are traded as Poecilotheria subfusca "Highland" and Poecilotheria subfusca "Lowland" or Poecilotheria subfusca "bara".

Highland form

The highland form is the species originally described as Poecilotheria subfusca Pocock , 1895. The females reach a body size of up to 5 cm. The males, on the other hand, only reach a height of no more than 4 cm. The highland form occurs at altitudes over 1600 meters and can also be found at heights over 2000 meters.

The individuals are all quite dark in color, as black and dark brown tones dominate the coloration on the carapace and the opisthosoma . The animals show dorsal a yellowish-beige drawing on the carapace, and on the legs, consisting of spots and lines. On the ventral side they have very few pale and narrow, light bands on their legs, which means that they practically do not have the warning coloration typical of the species . The chelicerae also have the dark basic color. The folium on the dorsal side of the opisthosoma is mostly reduced, especially in older females, and is covered at the edges by the dark base color, so that it stands out as a narrow, intense yellow spot in the middle of the dark opisthosoma. The dark central stripe of the folium is usually reduced and quite pale. The males only have a very pale, reduced folium with a very dark central stripe. The lateral tiger stripes on the opisthosoma are mostly lost as the animals get older, due to the increasingly darker color. It is assumed that the generally quite dark basic coloration serves as a "solar collector" for the animals to be able to warm up more easily after the cool nights while sunbathing.

Lowland shape

Individuals of the lowland form were described by Ralph V. Chamberlin in 1917 as Poecilotheria bara and later synonymous with the highland form (see systematics ). The lowland form occurs approximately at heights between 270 and 1600 meters above sea level. The animals are (considerably) larger than the highland form and the females are probably among the largest within the genus. Despite this difference, the similarities with the highland form are unmistakable. Only a few animals of this form are kept in terraristics, which is why most of the information on the drawing and size is based on the poor initial description. The individuals of the lowland form, however, are very similar in terms of their characteristics to the animals of the highland form.

The female type of Poecilotheria bara has a body length of 6 cm. The carapace is 24 mm long and 20 mm wide. The length of the legs is made up as follows:

  • Leg I: femur - 22 mm, patella + tibia - 31 mm, metatarsus - 17 mm, tarsus - 8 mm, total - 78 mm
  • Leg II: femur - 22 mm, patella + tibia - 30 mm, metatarsus - 18 mm, tarsus - 8 mm, total - 76 mm
  • Leg III: femur - 19.5 mm, patella + tibia - 24 mm, metatarsus - 16 mm, tarsus - 7 mm, total - 66.5 mm
  • Leg IV: femur - 22.7 mm, patella + tibia - 28 mm, metatarsus - 21 mm, tarsus - 8 mm, total - 79.7 mm

Poecilotheria uniformis holotypes

In Poecilotheria uniformis beach , 1913 it was the most controversial "nature" of the genus Poecilotheria , which now with Poecilotheria subfusca was seen as synonymous. The type specimens (2 males, 1 female, 1 juvenile female), which were described by Embrik Strand in 1913 and 1915, are medium-sized tarantulas with a body length of about 5 to 6 cm. Like all species of the genus, they have a recognizable dorsal folium (at least in females) on the otherwise monochrome, dark opisthosoma. The exact location is not known, as the collectors only indicated “Ceylon” (today's Sri Lanka). In particular, the morphological data from the work from 1915 provide information about the sizes and original colors of the holotypes. The specimens were collected in 1847 and had been in alcohol for 66 years when they were first described. However, according to the first description, the colors were still relatively well preserved. In the meantime, the type specimens have been heavily bleached and uniformly reddish-brown in color, which makes comparative investigations difficult, since colorings and drawing patterns are indispensable in differentiating the Poecilotheria species.

During the examination shortly after the first description, the two males were mostly greyish in color and stripe patterns on the legs could not be seen. The body length is 4.6 cm. The carapace is 18.5 mm long and 17 mm wide. The opisthosoma measures 19 mm in length and 11.5 mm in width. The chelicerae are 7.5 mm long. The eye hump is 4 mm wide and 2.2 mm long. The length of the legs is made up as follows:

  • Leg I: femur - 22 mm, patella - 10 mm - tibia - 19.5 mm, metatarsus - 18 mm, tarsus - 10 mm, total - 79.5 mm
  • Leg II: femur - 20 mm, patella - 9.5 mm - tibia - 17 mm, metatarsus - 16 mm, tarsus - 9.5 mm, total - 72 mm
  • Leg III: femur - 16 mm, patella - 8 mm - tibia - 13.5 mm, metatarsus - 15 mm, tarsus - 8.5 mm, total - 61 mm
  • Leg IV: femur - 20 mm, patella - 9 mm - tibia - 17.5 mm, metatarsus - 19 mm, tarsus - 10 mm, total - 75.5 mm
  • Pedipalp: coxa - 3.5 mm, trochanter - 2.5 mm, femur - 14 mm, patella - 7 mm, tibia - 11 mm, tarsus - 5 mm, total - 43 mm

The adult female still had light-colored bandages on her legs at the second examination. A dark central band in the folium was almost invisible, but the light part was well separated from the dark opisthosoma. The body length of the type is 6.2 cm. The carapace is 27 mm long and 23 mm wide. The opisthosoma measures 19 mm in length and 11.5 mm in width. The chelicerae are 12.5 mm long. The eye hump is 4.5 mm wide and 3 mm long. The length of the legs is made up as follows:

  • Leg I: femur - 22.5 mm, patella - 13.5 mm - tibia - 18 mm, metatarsus - 18 mm, tarsus - 10 mm, total - 82 mm
  • Leg II: femur - 21 mm, patella - 12 mm - tibia - 16 mm, metatarsus - 16 mm, tarsus - 10 mm, total - 75 mm
  • Leg III: femur - 16.5 mm, patella - 10 mm - tibia - 13 mm, metatarsus - 15 mm, tarsus - 9.5 mm, total - 64 mm
  • Leg IV: femur - 21 mm, patella - 11 mm - tibia - 17 mm, metatarsus - 19 mm, tarsus - 10 mm, total - 78 mm
  • Pedipalp: femur - 15 mm, patella - 8 mm, tibia - 11 mm, tarsus - 12 mm, total - 46 mm

Way of life

The animals can often be found in nature in old, thick trees, which due to their size can often be inhabited by several animals, but smaller specimens are also colonized by individual individuals. The spiders mostly hunt at night and are in their burrows during the day, where they can keep the temperature and humidity very stable. They prey on tree-dwelling insects and reptiles that are close to their web. The young nymphs and also the adult females are considered to be quite “ social ”, as they often live together in colonies in nature. The males, on the other hand, are considered to be more aggressive.

Reproduction

The mating of the animals takes place in nature during the rainy season. The construction of a cocoon then takes place in the significantly cooler dry season, whereby the young spiders are fully developed at the beginning of the warmer rainy season and can leave their mother's den. The cocoon usually contains between 40 and 100 eggs. Larger females rarely have much larger cocoons with up to 200 eggs. The so-called pre- larvae hatch from the eggs after about four weeks and are almost completely immobile due to their yolk-filled opisthosoma. A molt in a second pre-larval stage, as for example in Poecilotheria metallica , does not take place. After a further three weeks they reach the larval stage, in which they are fully able to move and, with the help of their mother, can leave the cocoon. However, the larvae do not yet ingest any external food. After about three weeks in the mother's nest, the larvae molt into completely independent nymphs. With a body length of only approx. 8 mm, young nymphs are among the smallest of the genus. The young nymphs leave their mother's nest very late or even after they have molted, so that sometimes two generations or more can be in the same nest.

Systematics

The species status of the species or form group around Poecilotheria subfusca Pocock , 1895 is controversial. Poecilotheria subfusca was described in 1895 by Reginald I. Pocock using animals of the highland form. In 1917 Ralph V. Chamberlin described animals of the lowland form as Poecilotheria bara without probably comparing the specimens available to him with the holotypes of Poecilotheria subfusca and Poecilotheria uniformis , as Peter J. Kirk later noted in the work on the synonymization with Poecilotheria subfusca . This can be concluded from the lack of comparisons with the other previously known species and the vague description.

Although Poecilotheria uniformis Strand has not been found since it was first described in 1913, the species status remained for 100 years until it was revised by Ray Gabriel et al. received in 2013. Gabriel et al. could in spite of the bad material obtained using UV -light and by comparison with other holotypes show that the type specimens of Poecilotheria uniformis strong similarities with respect to the ventral drawing of the walking legs and the expression of the Foliums to the holotype of Poecilotheria subfusca and Poecilotheria bara comprise . The holotypes also show the two humps typical of Poecilotheria subfusca in the stridulation organ. Krehenwinkel et al. also noted in 2008 that the delicate and otherwise very similar structure of the globe of the male holotype of Poecilotheria uniformis suggests at least a very close relationship to Poecilotheria subfusca .

Terrarium keeping

Because of their beautiful appearance, the animals are increasingly kept and bred in terrariums. Krehenwinkel et al. recommend keeping them at a daytime temperature of approx. 25 ° C and a relative humidity of over 80%. The dimensions of the terrarium should not be less than 20 × 20 × 30 (L × W × H) for adult females. The animals are very sensitive to drought and higher temperatures, which is why the parameters must be monitored, especially in summer. Young nymphs are also very sensitive to cool temperatures, whereas adults are quite resistant to cold. For offspring, well-nourished females should experience cooler temperatures of around 15 ° C for around 2 months after mating (which is more likely to lead to cannibalism ) in order to stimulate cocooning. The nymphs can often be kept in small groups even beyond the first year of life, without failures due to cannibalism. Adequate feeding is, however, essential. Adult females can usually be kept together with several young animals without any problems. Adult animals are only conditionally suitable for keeping in groups. Since males have a particular tendency to be aggressive, keeping them in groups is usually impossible. Due to the precise keeping parameters and the sensitivity of the young nymphs, Poecilotheria subfusca is not suitable for beginners.

Web links

Commons : Poecilotheria subfusca  - collection of images, videos and audio files

Poecilotheria subfusca in the World Spider Catalog

literature

Individual evidence

  1. ↑ a b c d e f g h i j k l H. Krehenwinkel, T. Maerklin, T. Kroes: Ornamentvogelspinnen - The genus Poecilotheria. Herpeton, Offenbach 2008, ISBN 978-3-936180-27-5 , pp. 37-40, 59-78, 163-170, 176.
  2. ↑ P. Klaas: tarantulas. Ulmer, Stuttgart 2003, ISBN 3-8001-3696-1 , pp. 103-109.
  3. ↑ Comparison of Poecilotheria subfusca "Highland" and "Poecilotheria subfusca" "Lowland" ( picture )
  4. ↑ Newsletter No. 8 of August 11, 2009 at www.poecilotheria.com (PDF)
  5. ^ A b R. V. Chamberlin: New spiders of the family Aviculariidae. In: Bulletin of the Museum of Comparative Zoology at Harvard College. 61, 1917, pp. 25-75.
  6. ↑ a b c R. Gabriel, R. Gallon, A. Smith: The revised taxonomic status of some Poecilotheria species Simon, 1885 (Araneae: Theraphosidae). In: British Tarantula Society Journal. 28 (3), 2013, pp. 103-110.
  7. ^ E. Strand: New Indo-Australian and Polynesian spiders in the Senckenberg Museum. In: Archives for Natural History. 79 (6), 1913, pp. 113-123.
  8. ^ A b c E. Strand: Scientific results of the Hanseatic South Sea Expedition 1909: III. Indo-Australian, Papuan and Polynesian spiders from the Senckenberg Museum, collected by Dr. E. Wolf, Dr. J. Elbert et al. In: Abhandlungen der Senckenbergische Naturforschenden Gesellschaft. 36 (2), 1915, pp. 179-274.
  9. ↑ Dorsal drawing of the female type of Poecilotheria uniformis Pocock , 1895 ( picture )
  10. ↑ RI Pocock: On a new and natural grouping of some of the Oriental genera of Mygalomorphae, with descriptions of new genera and species. In: Annals and Magazine of Natural History. Series 6, Vol. 15, 1895, pp. 165-184.
  11. ↑ PJ Kirk: A new species of Poecilotheria (Araneae: Theraphosidae) from Sri Lanka. In: British Tarantula Society Journal. 12 (1), 1996, pp. 20-30.