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Abnormalities in theraphosid spiders

 Here I want to stop on interesting facts, connected with different ugliness, which in single occasions had been met in captivity.

Such information does not find any mentioning in literature (except one case illustrated in a book). There are several confirmed cases known in the world.Three of them are connected with birth of spiders with two abdomens. In 2001 Britain Guy Tansley has published on his Internet site several photography of spiderling of tarantula species Holothele incei he has get in the brood born in his collection. However, unfortunately this spiderling has died before the first molt.

Specimen of tarantula-hybrid Brachypelma albogans with two opisthosoma

The second case was documented in the same year in collections of former Moscow hobbyist Alexey Sergeev. Amongst 800 of newborn spiderlings of interspecies hybrid between Brachypelma albopilosum х Brachypelma vagans one spiderling has been noted to have two abdomens. This spiderling was lately sexed as a female, grows large to the normal size, molts and eats well. Only time will show insofar long she will live since reasons of such anomaly in world of invertebrates does not known, and it is impossible Acanthoscurria insubtilis adult male with double-opisthosoma (c) Frederic Cletonto do any motivated further prognosis (for information available indirectly from the main source the tarantula had died was living in total near 8 years (died late 2008 - early 2009).

The third documented case has known due to a publication of the book “LES MYGALES; DECOUVERTE ET ELEVAGE” by J.M Verdez and F. Cleton. On the one of the pages authors share the picture of the therasphosid species Acanthoscurria insubtilis with two (double) abdomens. The specimen described by authors was the male and it is already has been dead (Verdez, J.M; pers. comm.).

Photo (c) and specimen courtesy of Cedrik Grenier

Another one very unusual and interesting fact has also been discovered by hobbyist Cedric Grenier founding inspecting his brood of nymphs of African baboon spider Pterinochilus murinus the specimen with 2 pairs of silk appendages (spinnerets) and not completely divided abdomen (compare it with double-abdomen specimens).

Unlike many such other cases reported by hobbyists and arachnologists (not fully bifurcate carapace in nymph, and conjoined specimens– Ray Gabriel, 2006 – look for further BTS Journal article on the detailed description of these cases!) this nymph has already successfully molted in spiderling! 

The last rare case I have to collect up today is connected with the occurrence of not developed eyes and reduced ocular tubercle in “red-rump” tarantula of the genus Brachypelma “vagans-group”. German hobbyist Johannes Würffel after keeping this specimen for some time after closer inspection suddenly has found that his tarantula seems so purblind!

Brachypelma cf. vagans with reduced eyes and ocular tubercle

Amazingly, but not surprising due to a known weak vision in theraphosid spiders in general, this Brachypelma sp (poss. B. sabulosum) acting like the ordinary tarantula which has a full set of ocelli with well-developed ocular tubercle.

The same case has also reported by Ray Gabriel who knows of the same fact regarding the specimen of Grammostola rosea courtesy of Thomas Ezendam

I wish to thank all mentioned authors for sharing the information and providing with the data and photos of the above listed remarkable tarantulas specimens.

Another one set of the abnormalities in theraphosids are pertaining on the matter of different changes in coloration patterns.

To be continue…

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