Hitherto unrecorded species of Poecilotheria
(Tarantula) from Sri Lanka
Ranil Nanayakkara*, Nilantha Vishvanath*
*Bio-Diversity Education and Research (BEAR)
Introduction
Poecilotheria is a genus of the family Theraphosidea, consisting of sixteen species, ten in
India and six in Sri Lanka, i.e P. fasciata (Latreille 1803), P. pederseni (Kirk 2001), P.
ornata (Pocock 1899), P.Subfusca (Pocock 1895) P. smithi (Kirk 1996)and P. uniformis
(Strand 1913) which was recorded in 1913 by a single specimen)respectively.
Of the sixteen species, two historical records of poecilotheria namely P. vittata (Pocock
1895) (India) and P. uniformis (Strand 1913) (Sri Lanka) lack type specimens or any
descriptive information after the 2nd World War, therefore they are classified as void
records. Out of the fourteen species of poecilotheria described so far, three are
synonymous namely -
Original described Name
Synonym
Poecilotheria subfusca
Poecilotheria bara
Poecilotheria smithi
Poecilotheria pococki
Poecilotheria regalis
Poecilotheria gadgili
Table 1: The described name against the synonym
Species of spiders that belong to this genus are arboreal, they inhabit tree
holes, bark peel offs and on occasions houses and do not build webs to catch their
prey, but depend on speed, ambush and their venom to secure prey. This genus
confined to India and Sri Lanka, are known for their colourful markings, lighting fast
speed and potent venom, when compared to other species of Tarantulas. As in all
species of spiders, the females are significantly larger than the male and much more
colourful.
Comparing to other Theraphosid Tarantulas, the genus Poecilotheria does
not overlap with any of the Mygalomorph spiders. Poecilotheria spp. can be easily
distinguished from other Mygalomorph spiders, by the ventral surface of the animal. The
chain of black spots on the dorsal surface of the abdomen is one of the diagnostic
features of the genus poecilotheria differentiating from any other genus of tarantula.
Identification of the species can be established using the first and fourth leg patterns of
the ventral surface. Unlike other species of Tarantulas Poecilotheria spp. have bright
colour variations ventrally and dorsally, the colour varying from green to purple or
yellow to metallic blue.
Remarks & Discussion
The new species differs from other species of Poecilotheria found in Sri Lanka by the
possession of a ventral band across the abdomen, the only other species recorded so
far that posses a ventral band is found in mainland India namely Poecilotheria regalis,
P. regalis has a wider geographical distribution in India than is the norm for this genus.
The possible reason could be that steam trains were widely introduced & used in India
during the colonial regimes. Most such trains were wood fired, unlike in Sri Lanka. Stacks
of firewood for firing of the steam engines were often collected from the wooded areas
of the Western Ghats, which was the “homeland” of P.regalis and it is quite probable
that it was transported along with the wood to establish itself in its new environments.
Significantly, it has never been recorded outside India. Its original home range is in the
Northern half of Western Ghats and the nearest known P.regalis colony to Sri Lanka exist
in the north west of Madras in the Eastern Ghats.
Plate: Poecilotheria spp. (The new species)
The new Poecilotheria spp. was discovered in the northern part of Sri Lanka. Though
displaying the ventral band, the leg patterns of the first and fourth legs differ to that of
P.regalis, and are a unique diagnostic to the new species. Significantly, in its range it is
the only Poecilotheria spp. to be found. The closest other species to its range is
P.fasciata. Since P. fasciata and P. regalis are very similar,Possibilty exists of parallel
evolution, the white band appearing in specimens from both India and Sri Lanka….
Having observed and studied the species in its wild state for several months, we were of
the initial opinion that it belonged to the species P. regalis, found in India though not
recorded in Sri Lanka.
However there existed a shadow of doubt in our minds. The general opinion of those
who viewed the photos was that it was P. regalis. In our extensive observations and
comparisons against the recorded and described species to clear my doubts,
significant differences were noted. These differences noted during my study confirmed
my suspicions that it was a hitherto unrecorded species.
Our correspondence with World recognized authorities on Tarantulas resulted in very
useful guidance, for making a detailed study. On the lines of such guidance received.
We were pleasantly surprised that this creature did not conform to any of the six
varieties so far recorded from Sri Lanka or any of the species found in India. It was
thrilling and deep satisfying When world renown and recognized authorities on
Tarantulas me that very strong evidence exist to this particular creature belonging to a
species so far unknown and unrecorded to science.
Extensive studies have been made and currently the taxonomic process is in place. It
will be a proud moment for Sri Lanka when this new addition to it endemic fauna is
formally announced in the near future.
Reference
Pocock R.I. (1900), The Fauna of British India including Ceylon and Burma, Today and
Tomorrow printers and publishers, New Delhi, India, pp 24-25
Samarawckrama V. A. M. P. K., Janananda M. D. B. G., Ranawana K. B., and Smith, A,
(2005), Study of the distribution of the genus Poecilotheria of the family Theraphosidae
in Sri Lanka, Ceylon Journal of Science, (Bio. Sci.), Vol. 34, pp 75-86.
Smith, A and Kirk P, (2002), A Field Guide on the Theraphosid Spiders of India & Sri Lanka
particularly the genus Poecilotheria
Benjamin S. P and Bambaradeniya C.N.B, (2006), Systematic and conservation of
spiders in Sri Lanka; Current Status and Future Prospectus, IUCN-The World Conservation
Union, Fauna of Sri Lanka, 70-76.
IUCN Red List (2007), the 2007 Red List of Threatened Fauna and Flora of Sri Lanka, IUCNThe World Conservation Union.
Smith A.M. (2004) a new species of the arboreal Theraphosid, genus Poecilotheria, from
Southern India (Araneae, Myglomorphae, Theraphosidae) with notes on its
conservation status. Journal of British Tarantula Society 19 (2), 48-61
Kirk P. J. (1996). A new species of Poecilotheria (Araneae: Theraphosidae) from Sri
Lanka. Journal of British Tarantula Society 12 (1), 20-30.
Kirk P. J. (2001), A new species of Poecilotheria (Araneae: Theraphosidae) from Sri
Lanka. Journal of British Tarantula Society 16 (3), 77-81.
New species of Tarantula discovered in the wild, 25 October 2009, Sunday Island.