Poecilotheria

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Poecilotheria
Female of Poecilotheria regalis

Female of Poecilotheria regalis

Systematics
Class : Arachnids (arachnida)
Order : Spiders (Araneae)
Subordination : Tarantulas (Mygalomorphae)
Family : Tarantulas (Theraphosidae)
Subfamily : Poecilotheriinae
Genre : Poecilotheria
Scientific name of the  subfamily
Poecilotheriinae
Simon, 1892
Scientific name of the  genus
Poecilotheria
Simon , 1885
Ventral view of Poecilotheria regalis

Poecilotheria is a genus of the family of tarantulas (Theraphosidae) with currently 15 recognized species , exclusively on the Indian subcontinent (incl. Sri Lanka are common) (September 2018). It is the only genus in the subfamily Poecilotheriinae . In German-speaking countries, the species of the genus are sometimes also called ornament tarantulasor tiger tarantulas, although these names overlap with the German names for other tarantula species. The scientific generic name Poecilotheria is made up of the ancient Greek words "poikilos" (= colorful ). and "ther" or "therion" (= animal ). together and means something like "colorful animal". Due to their attractive appearance and the sometimes considerable size of the females, they have become very popular animals in terrariums and can now becared for and reproducedin terrariums with relatively little effort.

All representatives of this genus have been protected by CITES Appendix II since August 28, 2019 .

distribution

All species of the genus occur in India and Sri Lanka . The occurrence in Sri Lanka is extensive. There is no evidence in central India, nor in the north above 23.5 ° north latitude. Thus the occurrence is apparently determined by the geographic tropical border. However, there are suspicions that other species could also occur in northern India. The distribution in India is determined by the forest cover, which occurs along the coasts in an approximately 400 km wide strip. Due to the width of the country, the two strips converge to the south and the genus also occurs across the board from around half of India to the south. The total extent of the distribution area thus covers over 2000 km in north-south direction, over 1500 km in east-west direction and ranges from sea level to altitudes above 2000 m.

habitat

Forests of different climatic zones form the natural habitat of all species of the genus. All transitions occur, from hot dry or thorn forests to moist monsoon forests and the cooler mountain cloud forests . Due to human influences, some species have been pushed back to very small areas ( Poecilotheria smithi ) or were able to spread over large parts of India due to rather low demands on the habitat and occur in agriculturally used monocultures (mostly oil palms ) with sometimes very high population densities ( Poecilotheria fasciata ). Some species are even found in gardens and in human dwellings, so that some species can even be described as cultural followers .

features

They are medium to large tarantulas from 5 cm ( Poecilotheria subfusca ) to 9 cm ( Poecilotheria rufilata ) body length and 12 to 20 cm leg span. There is a gender dimorphism in terms of size and color between the sexes . Adult females are much more strongly built and more contrasty than the males. The adult males, on the other hand, are relatively more delicate and long-legged than the female animals and their high-contrast drawing on the upper side of the body gradually dissolves (except for Poecilotheria metallica ) from a certain stage of development or only after the moult. As a special feature, all species have a stridulation organ consisting of hair and bristles between chelicerae and buttons , with which they can make hissing sounds when threatened. Organs of similar structure can be found in the (probably more closely related) species of tarantula Psalmopoeus .

All species have dorsally an oak leaf- like leaf markings (folium) on the opisthosoma and different stripes and spots on the carapace and legs. Most species are dominated by gray tones with individual black elements on the dorsal side, such as the tiger stripes on the opisthosoma. However, some species also show shades of brown ( Poecilotheria miranda , Poecilotheria subfusca ), have yellowish drawing elements ( Poecilotheria rufilata , Poecilotheria subfusca , Poecilotheria metallica ) or are even colored blue ( Poecilotheria metallica ). In addition, red ( Poecilotheria formosa ) or pink ( Poecilotheria regalis , Poecilotheria striata ) hair can cover certain areas of the body.

On the ventral side , the legs are banded yellow-black or white-black. In Poecilotheria metallica and Poecilotheria rufilata there are also blue iridescent elements. If there are yellow bands, they replace the white bands on the dorsal side of the legs, which creates a particularly strong contrast between yellow and black bands. This very conspicuous color is a warning color for possible predators, who are threateningly shown the underside of the raised front body. In most cases, these drawings can be used to clearly identify the species.

The nymphs look rather inconspicuous at the beginning, even if the future drawing can already be recognized. They develop the typical, high-contrast drawing of the dorsal side at an early stage. The warning color on the ventral side of the treadmill does not appear until later.

Way of life

All species are tree inhabitants and prefer to live in tree hollows , knotholes or, less often, under loose bark. Open hiding places are rarely used. A population of Poecilotheria regalis , as the most adaptable species of the genus, is even said to inhabit crevices in the rock and some individuals have been seen fleeing while diving in tree stumps full of water. The diameter of the tree hollows is chosen so that it corresponds roughly to the body length of the animals. Species that show less social tendencies and thus also show a lower density of individuals in their range choose relatively narrow, tall trees. In contrast to such species, Poecilotheria subfusca in particular shows a strong tendency towards colony formation. Animals of this kind often inhabit very old trees with a large trunk diameter. In these trees (e.g. cypresses ) there are many cavities that offer the relatively small animals sufficient space and are therefore inhabited by several adult animals. Young animals live in hiding places on the ground in exceptional cases, but this is atypical.

In most cases, the hiding places are chosen according to very specific criteria. Hollow spaces are preferred, the opening of which is deep or directed downwards so that rainwater can hardly penetrate (there are exceptions here for some species). The openings are often only large enough for the animals to just fit through. This has the advantage that in dry climates only little moisture can escape through the small openings, which are also very tightly closed with web during the day. This ensures the animals a microclimate in which they can survive at all during the sometimes very harsh dry season. Since the animals are mainly active at twilight and nocturnal, due to this constant microclimate they hardly experience any temperature and humidity differences when leaving the shelter, as the microclimate is usually very close to the conditions at night.

Some species show behavior towards conspecifics that is unusually tolerant for tarantulas, so that sometimes a large cave is inhabited by several adult females and brood care in the form of defense and feeding of the hatched young spiders has even been observed. Since there are no observations of cooperation between adult animals, one cannot yet speak of real sociality .

Defense behavior and toxic effects

Contrary to popular belief, the tarantulas of the genus Poecilotheria are only slightly aggressive, although individual differences may exist. They usually retreat quickly to their hiding place even if there is only minor disturbance and avoid a direct confrontation with the troublemaker. In the absence of suitable hiding places or opportunities to escape, the animals turn towards the attacker and take a defensive position. They present the warning color under the forelegs and generate hissing sounds by means of their stridulation organ. If the disturbance persists, they first hit the attacker with their front legs before choosing the poison bite as the last option to drive the attacker to flight.

The poison of the Poecilotheria species is stronger than that of most other tarantulas. The consequences are local, sometimes radiant pain, local swelling and severe redness that can last up to a week, as well as cramps that can affect various muscles and last for several days. An assessment by a doctor should therefore always be carried out. Caution is required, especially for allergy sufferers , as the poisonous effect can be stronger here. There is still no direct antidote to the cramps, as the composition of the nerve poison that triggers them has not yet been clarified biochemically.

development

As with all tarantulas, the mother animals take care of the cocoon by rotating it regularly and carrying it around in their den. In contrast to the usual development in young spiders from an egg through a prelarva and a larva to a nymph and finally to a sexually mature animal, there is a further development stage in the species Poecilotheria formosa , Poecilotheria metallica , Poecilotheria miranda and Poecilotheria tigrinawesseli . In these tarantulas, a distinction is made between larva I and larva II during larval development. In these species, larva II corresponds to the “normal” larva of other spiders, whereas larva I represents an intermediate form in development. This form seems to be an adaptation to the climate due to a delay in development of about 3 weeks and cannibalistic tendencies (especially with otherwise very tolerable species). During the period in which this stage of development occurs (premonsoon) there is little food due to drought and heat, so that development delays and cannibalism ensure the survival of at least some young animals until the climatic conditions are more favorable and the food supply is larger.

The same stage of development was observed in tarantula species of the genus Psalmopoeus .

Systematics

Within the family of tarantulas (Theraphosidae), the genus according to Günter Schmidt is placed in a separate subfamily, the Poecilotheriinae. Due to the unique development of some species with two larval stages, according to the parsimony principle, it can be assumed that the genera Poecilotheria and Psalmopoeus ( Psalmopoeinae incl. Tapinauchenius ) are directly related to one another as sister taxa. However, the relationships between the two genera, or the three genera of the two subfamilies, have not yet been conclusively clarified. Some authors, such as B. Robert J. Raven , put the three genera together with some others in the subfamily Selenocosmiinae . The internal systematics of the genus Poecilotheria has also not yet been clarified, even if there are individual references to the family relationships. The position of Poecilotheria metallica as the most derived (youngest) species within the genus is likely to be secured, since it is the only species in which there is almost no sex dichromatism and the spermathec of the females is divided into two parts.

species

Female of Poecilotheria rajaei

The World Spider Catalog currently lists 15 species for the genus Poecilotheria . (As of September 2018)

Synonyms

There are a number of recognized synonyms of almost all species in the genus. Gabriel et al. revised in 2013 the assignment of some synonyms and the validity of some taxa whose species status has been questioned. In addition, there are still some species and groups of species whose systematic status has not yet been conclusively clarified.

The species status of Poecilotheria hanumavilasumica Smith , 2004 is at least questionable. The species differs from Poecilotheria fasciata only by a very small black stripe ventrally on the femora of the 4th pair of legs. Krehenwinkel et al. mention that the ventral drawing is not completely stable internally. This is also observed by terrarium keepers with Poecilotheria ornata . There are two color forms of this species ( Poecilotheria ornata and Poecilotheria ornata "light form" or Poecilotheria ornata "blue"), which also differ only in a small variation of the ventral pattern on the femora of the 4th pair of legs. Hobby keepers also report that animals of both color forms can hatch from the same cocoon.

Due to the instability of some intraspecific morphological features, Poecilotheria nallamalaiensis Rao , Bastawade , Masqsoodjaved & Krishna , 2006 in 2010 through an earlier revision by Ray Gabriel, lost its species status and was synonymous with Poecilotheria formosa . The authors around Rao used, among other things, the number of humps on the inside of the Tastercoxa as a distinguishing feature from Poecilotheria formosa . However, in investigations of several Poecilotheria formosa specimens from the same distribution area, Gabriel found that this characteristic is also highly variable.

It is also difficult with the Poecilotheria subfusca species or form group. A highland form and a lowland form are often used here. Both forms differ considerably in size, dorsal color and the altitude of the distribution area in Sri Lanka. It is assumed that the forms are Poecilotheria subfusca Pocock , 1895 (highland form) and Poecilotheria bara Chamberlin , 1917 (lowland form), where Poecilotheria bara is currently a synonym of Poecilotheria subfusca . This group of species also includes Poecilotheria uniformis Strand , 1913, which has not been found since its first description and is only known from one female and one male type specimen . The species status has now been revoked and Poecilotheria uniformis Strand is a synonym for Poecilotheria subfusca Pocock .

The revision of Gabriel et al. the status of Poecilotheria vittata Pocock , 1895, could also be clarified after a long time , which raised it to species status and the name Poecilotheria pederseni Kirk , used until then , was established as a synonym in 2001. Poecilotheria vittata was considered a synonym of Poecilotheria striata since a work by Peter J. Kirk in 1996 .

Above all Poecilotheria pococki Charpentier , 1996 had not been unofficially recognized for a long time and was already recognized before the revision by Gabriel et al. 2013 by Krehenwinkel et al. and Nanayakkara et al. Listed as a synonym of Poecilotheria smithi Kirk , 1996. This view has also been taken and generally accepted by various authors.

Web links

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

Poecilotheria in the World Spider Catalog

literature

Individual evidence

  1. ↑ a b c d Natural History Museum of the Burgergemeinde Bern: World Spider Catalog Version 19.5 - Poecilotheria . Retrieved September 29, 2018.
  2. ↑ P. Klaas: Vogelspinnen Ulmer, Stuttgart 2003, ISBN 3-8001-3696-1 , pp. 103-109.
  3. ↑ Updates on decisions made on proposals to amend Appendices I and II at CoP18 ; accessed on September 23, 2019
  4. ↑ a b c d e f g h i j k l m H. Krehenwinkel, T. Maerklin, T. Kroes: Ornamentvogelspinnen - The genus Poecilotheria. Herpeton, Offenbach 2008, ISBN 978-3-936180-27-5 .
  5. ↑ Ventral drawings of the genus Poecilotheria ( picture )
  6. ↑ a b Poecilotheria , Simon 1885: "Pictorial key using ventral leg patterns." ( Website with picture ) (Norwegian)
  7. ↑ N. Ahmed, M. Pinkham, DA Warrell: Symptom in search of a toxin: muscle spasms following bites by Old World tarantula spiders (Lampropelma nigerrimum, Pterinochilus murinus, Poecilotheria regalis) with review . In: QJM . tape 102 , no. December 12 , 2009, pp. 851-857 , doi : 10.1093 / qjmed / hcp128 ( PDF ).
  8. ↑ G. Schmidt: The position of the genus Poecilotheria in the system. In: Arachnida. (Switzerland) 3 (10), 1995, pp. 4-5.
  9. ^ Robert J. Raven: The spider infraorder Mygalomorphae (Araneae): Cladistics and systematics . In: Bulletin of the American Museum of Natural History . tape 182 , 1985, pp. 1-180 ( PDF ).
  10. ↑ ZA Mirza, RV SANAP, H. Bhosale: Description of a new species of arboreal tarantula of the genus Poecilotheria Simon, 1885 (Araneae: Theraphosidae) from Satpura Hills, Central India. In: Journal of the British Tarantula Society. 29 (2), 2014, pp. 60-65.
  11. ↑ a b RP Nanayakkara, PJ Kirk, SK Dayananda, GASM Ganehiarachchi, N. Vishvanath, TGT Kusuminda: A new species of tiger spider, genus Poecilotheria, from northern Sri Lanka. In: British Tarantula Society Journal. 28 (1), 2012, pp. 6-15. (PDF)
  12. ↑ a b c d 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.
  13. ^ Image by Droguet & Vignaud, 2007 ( image ( Memento from November 11, 2013 in the Internet Archive ))
  14. ↑ Ventral drawing of Poecilotheria ornata and Poecilotheria ornata "light form" ( picture )
  15. ↑ Poecilotheria ornata on www. poeci1.de ( Link ) (accessed on October 11, 2015)
  16. ^ R. Gabriel: Poecilotheria nallamalaiensis Rao et al., 2006, a junior synonym of Poecilotheria formosa Pocock, 1899. In: Newsletter of the British Arachnological Society. 118, 2010, pp. 12-15.
  17. ↑ a b PJ Kirk: A new species of Poecilotheria (Araneae: Theraphosidae) from Sri Lanka. In: British Tarantula Society Journal. 12 (1), 1996, pp. 20-30.
  18. ↑ RP Nanayakkara, N. Vishvanath: hitherto unrecorded species of Poecilotheria (Tarantula) from Sri Lanka. National Science Foundation Newsletter. (PDF) ( Memento of the original dated December 24, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.nsf.ac.lk
  19. ↑ Petition to list 11 Tarantulas in the Genus Poecilotheria under the US Endangered Species Act (PDF)
  20. ^ Convention on international trade in endangered species of wild fauna and flora - Amendments to Appendices I and II of CITES: Eleventh Meeting of the Conference of the Parties. Proposal 11.52. (PDF) ( Memento of the original from March 6, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. @1@ 2Template: Webachiv / IABot / www.cites.org