Theraphosidae includes large hairy spiders commonly called tarantulas in the group Mygalmorphae. The family consists of 983 species in 140 genera, of which some are poisonous (WSC, 2017). The present project intended to create a database about theraphosid spiders in Western Ghats of Kerala state. The main objectives of the project were collection of reference specimens, description of new species and poorly described species on the basis of modern

taxonomical standards.

 

Sites selected for spider collection

 

Site 1 -Kulathupuzha Reserve Forest

Site II- Achankovil Reserve Forest

Site III - Bheemanadi Reserve forest

Site IV- Marangattupilly

Site V- Thattekkad bird sanctuary

Site VI- Maalippara

Site VII- Vellikulangara.

Site VIII- Pooyankutty

Site IX- Chimminy Wildlife Sanctuary.

Site X- Chinnar Wildlife Sanctuary

Site XI- Vakathanam

Site XII- Nelliyampathy

Site XIII- Kattilappara

Site XIV- Plappally

Site XV- Vadasserikkara

Site XVI- Nilambur

Site XVII-Agasthyavanam Biological Park

Site XVII- Kuttampuzha

Site XIX- Parambikulam Wildlife Sanctuary

Site XX- Idukki Wildlife Sanctuary

Site XXI- Mundakayam forest area

Site XXII- Kakkayam

Site XXIII- Peechi Wildlife Sanctuary

 

Methodology

Spiders were studied mostly in their natural dwellings. Identification was done with the help of relevant literature and by referring with experts. Specimens are preserved in 70% alcohol. Measurements are expressed in mm and were taken

with ocular micrometers. Morphological studies and photography were done by a Labomed CZM6 Stereo zoom Microscope attached with a Canon EOS 600D Digital Camera, with EF10mm f/2.8 macro USM having Remote Capture

Software. Information that could be collected from local and tribal people regarding each species was recorded. Field visits were undertaken to the type localities of all the previously described species to evaluate the present position. Photographs of burrow and habitat were taken in each species. Maps  were prepated using online tool available at https://www.mapcustomizer.com. The exact geographical localities were determined with the help of GPS facility

of Nikon D3500 Digital Camera.

Species described during the study.

I. Annandaliella

1. Annandaliella ernakulamensis Jose & Sebastian 2008

2. Annandaliella nigra sp. nov.

3. Annandaliella pectinifera Gravely, 1935.

4. Annandaliella travancorica Hirst, 1909

II. Chilobrachys

5. Chilobrachys fimbriatus Pocock, 1899

III. Haploclastus

6. Haploclastus devamatha sp. nov

7. Haploclastus kayi Gravely, 1915.

8. Haploclastus nilgirinus Pocock, 1899

IV. Neoheterophrictus

9. Neoheterophrictus chimminiensis sp.nov.

10. Neoheterophrictus bhori (Gravely, 1915)

V. Poecilotheria

11. Poecilotheria hanumavilasumica Smith, 2004

12. Poecilotheria regalis Pocock, 1899

13. Poecilotheria rufilata Pocock, 1899

14. Poecilotheria striata Pocock, 1895

VI. Sahydroaraneus

15. Sahydroaraneus hirsti Mirza & Sanap, 2014.

16. Sahydroaraneus raja Gravely, 1915

17. Sahydroaraneus sebastiani Jose, 2017

VII. Thrigmopoeus

18. Thrigmopoeus psychedelicus Sanap & Mirza, 2014

19. Thrigmopoeus trunculentus pocock, 1899

 

New species discovered during the study:

One of the major achievements is the discovery four new theraphosid species from Western Ghats. The Annandaliella nigra sp. nov. was discovered from the forest area near Salim Ali Bird Sanctuary in Thattekkad. The species is named

A.nigra due to the dark black colour of the adults and can be separated from A.travancorica Hirst, 1909 by the presence of twin spermathecal lobes diverging from each other, distal end with club shaped lateral bud. Three intercheliceral

spines on the opposed surfaces of chelicerae.

 

Haploclastus devamatha Prasanth and Jose, 2014 is a beautiful theraphosid spider with bluish reflections which are discovered from the Kulathupuzha- Achenkovil areas of Kollam District. It differs from H. Kayi Gravely, 1915 by Bluish reflections on the dorsum of carapace, chelicerae and coxa to tibia of all legs; Prolateral face of maxillae with 1 or 2 rows of longitudinally arranged thorn setae below suture, few scattered and 2 longitudinal rows above the suture.

 

Neoheterophrictus chimminiensis sp.nov is another new species found from the Chimmini Wildlife Sanctuary, Thrissur District. They were collected beneath fallen logs. It can be separated by from Neoheterophrictus bhori (Gravely, 1915) in the shape of multilobed spermatheca, which is many lobed in N. bhori (Mirza et.al. 2014) while only four lobes exists

in N.chimminiensis; besides spermathecal stalks are more closely placed in N.  bhori than in N.chimminiensis (Mirza et al. 2014).

 

Sahydroaraneus sebastiani Jose, 2017 is collected from Chimmini wildlife sanctuary beneath decaying logs from moist deciduous forests. It can be separated from related S.collinus Pocock 1899 by spermathecal stalks with equal diameter ending in a single lobe while in S.collinus Pocock 1899 spermathecal stalks are being wider at base and narrower distal end bears a single lobe. Coxae of legs I–II without any stridulatory setae unlike S.collinus Pocock 1899.

 

Redescribed species during the study:

Annandaliella pectinifera Gravely, 1935 is common in central Kerala, mostly collected from Kottayam district. They are characterized by presence of Intercheliceral spine and a comb like apophysis on the inner side and a spine on the

outer side of tibia I. It differs from A.travancorica by the nature of palp and presence of inter-cheliceral spines. The spermathecae of female consist of two receptacles, diverging from each other, each receptacle ends in two buds, one is globular and the other is reduced.

 

Annandaliella travancorica Hirst, 1909 is known from most parts of Kerala, including south, north and central parts. It has been collected from Trivandrum, Kozhikode, and Trichur. It differs from the nearest relative A.ernakulamensis Jose & Sebastian, 2008 by the absence of tibial comb and two lateral spines at the distal end of tibia I, from A.pectinifera Gravely, 1935 it differs by the absence of tibial comb, and one lateral spine at the distal end of tibia I. Stridulating spines on the inner surface of chelicerae absent in A.travancorica Hirst, 1909.

 

Haploclastus kayi Gravely, 1915 was previously known only from Parambikulam. During the study this species has been collected from Nilambur in Malappuram district. H. kayi Gravely, 1915 can be separated by other similar species by the light grey colour of the upper surface of the patellae and tibiae of the anterior legs (Gravely, 1915). Poecilotheria striata Pocock, 1895 was collected from Thattekkad. This is the most wide spread species of Poecilotheria in Kerala, reported from Trivandrum, Kottayam, Palakkad, Ernakulam, Pathanemthitta and Kollam districts of Kerala. It can be distinguished by the presence of bright yellow and black patterns ventrally on legs I-II. Femur is yellow with broader black diagonal band about three quarters distally, patella proximally yellow with black and irregular band across the middle.

 

New records

Poecilotheria hanumavilasumica Smith, 2004 is being reported from Chinnar area. This extends its distribution further west from Rameshwaram Island, Ramanthapuram and Mandapam in India. Similarly the discovery of Thrigmopoeus trunculentus pocock, 1899 from Kasargod in Kerala extends its distribution further south from Karnataka and Maharashtra.

Species diversity

19 species belonging to genera Annandaliella, Chilobrachys, Haploclastus, Neoheterophrictus, Poecilotheria, Sahydroaraneus and Thrigmopoeus are recorded during the study. The highest number of specimens collected belongs to the genera Haploclastus.

Endemism

Fifty percent of the species collected during the study are endemic to Western Ghats. Genera like Annandaliella, Sahdroaraneus, Plesiophrictus and Neoheterophrictus, are endemic to south western peninsular India, where as

Poecilotheria species are found in India and Srilanka. 

 

Affinities of theraphosids

Genus Poecilotheria is known only from India and Srilanka, seven species are known from Srilanka and nine species are known from India. All three species of Annandaliella are known only from Western Ghats. All seven species of

Haploclastus and all seven species of Neoheterophrictus are known from India. Three reported species of Sahydroaraneus and Thrigmopoeus are known only from India.

 

Conservational risks.

The most important factor in protecting these species is their habitat preference, most species are ground dwelling, so factors affecting the ground vegetation and soil structure creates trouble for the survival of these spiders. In addition regarding some colourful theraphosids like Poecilotheria there has been reports of illegal smuggling of these species for rearing as pet animals in the vivariums in Europe and America. The attitude of tribal people clearly demonstrates that the people are offering money to collect these spiders. During the research only the essential number of specimen were collected for the identification. The recent land excavations for constructions of buildings in areas adjoining to the forests are also posing grave threats to these little known creatures.

Conservational status

Several important sites were discovered having a comparatively higher density of theraphosid spiders are recorded during the study. The Achankovil and Kulathupuzha forest area has a rich population of Haploclastus devamatha

species compared with other parts. I recommend special efforts to be taken to keep the habitats of these areas intact and to prevent species smuggling from these areas. The discovery of Pecilotheria hanumavilasumica from Chinnar area is major achievement of the project. It extended the know range of this species further west.

 

The discovery of Thrigmopoeus trunculentus pocock, 1899 from Kasargod, in the northern Kerala and Thrigmopoeus psychedelicus Sanap & Mirza, 2014 from Tenmalai area in south Kerala indicates that two closely related species are

occupying the state.

 

Protection of theraphosids in Kerala.

Most of the species recorded during the study were collected from protected sanctuaries. This indicates that adequate level of protection is offered to theraphosids in Kerala. Considering their poor dispersal nature, it is recommended the contiguity of forest patches should be provided in order to increase the distribution of the species.

 

Population assessment.

The project revealed that the Haploclastus devamatha has a higher abundance in south states of Kerala like Kollam and Pathanamthitta. The presence of Sahyadroaraneus in northern districts of Kerala are more compared to southern districts. The discovery of Poecilotheria hanumavilasumica from chinnar area is major achievement of the project. It extends the range of the species to further east than originally thought. 

 

Out of 19 theraphosid spiders included in the IUCN red list seven are recorded from Kerala during the study. 

 

Chilobrachys fimbriatus, Haploclastus kayi, Poecilotheria hanumavilasumica, Poecilotheria regalis, Poecilotheria rufilata, Poecilotheria striata, Thrigmopoeus truculentus. The status of Poecilotheria regalis, that was reported as least

conern, had not been collected much, this indicates its restricted distribution.

 

Awareness among the people.

Most people in Kerala have very little knowledge about the existence of larger hairy tarantula spiders in Kerala. Those who have seen these spiders are very much afraid of them. These spiders are usually found in places near to forest

and people often kill them thinking they are deadly poisonous for human beings. Tribals also consider Poecilotheria and Haploclastus highly dangerous, they don’t go near their nest or such trees. Tribals believe a bite of Poecilotheria

will make them curl their body like a spider. This belief might have caused due to the intense pain bite causes.

 

Major recommendation of the study:

The Western Ghats forms a rich diversity of primitive and endemic spiders. The conservation of the pristine forests of Western Ghats should be given more attention to prevent their damage due to ecological and man-made reasons.

Proper awareness should be imparted to tribals so smuggling of these tarantulas can be controlled. A few cases have come to my notice that if you are paying them tribals are ready to capture any number of specimens. Westerners are exploiting this for smuggling of specimens. The proper awareness should be given to forests, customs and other enforcement personnel to prevent their smuggling. 

 

Continuity of forest patches should be maintained so that gene pool of these species are not broken preventing their inbreeding and slow extinction. The present work only focused on taxonomy of these tarantulas. Further studies about their ecology and behavior are needed to conserve these spiders. Tarantulas are highly localized with restricted migration. Constructional activities and flooding of forest patches during new dams destroy the limited habitats of these spiders leading to their extinction.