Description of male Tylorida sataraensis Kulkarni, 2014 (Araneae, Tetragnathidae) with notes on habits and conservation status

Abstract

The male sex of Tylorida sataraensis Kulkarni, 2014 is described based on specimens from the type locality. The distinguishing characters from its closest species Tylorida ventralis (Thorell, 1877) are detailed. An interesting behaviour of going underwater by T. sataraensis, on disturbance is recorded and tested for significance. The surveys have shown sighting of this species only to the perennial streams of the rocky outcrops in Satara region. The potential threats to this species and the possible conservation status based on known distribution are discussed.

Full text

Biodiversity Data Journal 3: e4451
doi: 10.3897/BDJ.3.e4451
Taxonomic Paper
Description of male Tylorida sataraensis
Kulkarni, 2014 (Araneae, Tetragnathidae) with
notes on habits and conservation status
Siddharth Shrikant Kulkarni , Todd R Lewis
† Biome Conservation Foundation, Pune, India
‡ Zoology Department, Yashavantrao Chavan Institute of Science, Satara, Satara, India
§ Westfield, 4 Worgret Road, Wareham, Dorset, BH20 4PJ., Dorset, United Kingdom
Corresponding author: Siddharth Shrikant Kulkarni (sskspider@gmail.com)
Academic editor: Gergin Blagoev
Received: 05 Jan 2015 | Accepted: 13 Feb 2015 | Published: 16 Feb 2015
Citation: Kulkarni S, Lewis T (2015) Description of male Tylorida sataraensis Kulkarni, 2014 (Araneae,
Tetragnathidae) with notes on habits and conservation status. Biodiversity Data Journal 3: e4451. doi: 10.3897/
BDJ.3.e4451
Abstract
The male sex of Tylorida sataraensis Kulkarni, 2014 is described based on specimens from
the type locality. The distinguishing characters from its closest species Tylorida ventralis
(Thorell, 1877) are detailed. An interesting behaviour of going underwater by T.
sataraensis, on disturbance is recorded and tested for significance. The surveys have
shown sighting of this species only to the perennial streams of the rocky outcrops in Satara
region. The potential threats to this species and the possible conservation status based on
known distribution are discussed.
Keywords
Tetragnathid spider, laterite rocks, streams, seasonal surveys, population marginalisation,
endangered species
†,‡ §
© Kulkarni S, Lewis T. This is an open access article distributed under the terms of the Creative Commons Attribution License
(CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and
source are credited.

Introduction
The genus Tylorida Simon, 1894 was established on the basis of a male Tylorida striata
(Thorell, 1877) whose holotype depository details are unknown (Álvarez-Padilla and
Hormiga 2011). There are ten currently described species for Tylorida (World Spider
Catalog 2014). Most of these are distributed in Australasia except for Tylorida seriata
Thorell, 1899 that extends to West Africa and Cameroon (Álvarez-Padilla and Hormiga
2011). To date, three species of Tylorida are reported from India; Tylorida culta (O. P.-
Cambridge, 1869), Tylorida sataraensis Kulkarni, 2014 and Tylorida ventralis (Thorell,
1877). Tylorida culta is also reported from Sri Lanka and T. ventralis has a wider
distribution from India, to Taiwan, Japan and New Guinea.
Materials and methods
Seven streamside transect surveys of up to 400m were conducted for spiders during 2012,
2013 and 2014. Specimens were collected by visual searching from perennial streams
among secondary montane forest along T. sataraensis type locality; Chalkewadi (17.478°
N, 73.836°E; 1078m ASL) and Kaas (17.721°N, 73.808°E; 1123m ASL) plateaus of Satara
district, India. Males of the species were confirmed by observing copulation. Specimens
were collected on private land whilst engaged on permitted surveys for other fauna.
Specimens were examined using a Brunel IMXZ™stereozoom microscope and imaged
using Canon 1200D™ mounted camera. Statistics were performed in Statsoft Statistica
Ver. 7.0™ (StatSoft 2011). Mapping was prepared using DIVA GIS™ v7.5c. All specimens
were deposited at Bombay Natural History Society, Mumbai. All the morphological
measurements are in millimeters. Abbreviations used: AME - anterior median eyes, PME -
posterior median eyes, CDBP - Cymbial dorsobasal process, ASL - Above sea level, BNHS
- Bombay Natural History Society, IUCN - International Union for Conservation of Nature.
Taxon treatment
Tylorida sataraensis Kulkarni, 2014
•ZooBank urn:lsid:zoobank.org:pub:7CDB5A97-C7DB-452F-9BB8-0C5A9F071E9F
Materials
a. scientificName: Tylorida sataraensis; taxonomicStatus: accepted; kingdom: Animalia;
phylum: Arthropoda; class: Arachnida; order: Araneae; family: Tetragnathidae;
taxonRank: species; genus: Tylorida; specificEpithet: sataraensis;
scientificNameAuthorship: Kulkarni, 2014; continent: Asia; country: India; countryCode:
IN; stateProvince: Maharashtra; municipality: Satara; locality: Chalkewadi;
verbatimLocality: Chalkewadi sada; verbatimElevation: 1078 m;
georeferenceVerificationStatus: Verified by collector; samplingProtocol: Hand picking;
eventDate: 05/06/2013; habitat: Rocky plateaus; individualCount: 1; sex: 1 male;
lifeStage: Adults; catalogNumber: BNHS Sp. 119; recordedBy: V. Deshpande;
2Kulkarni S, Lewis T

identifiedBy: Siddharth Kulkarni; dateIdentified: 08/05/2014; language: en; rightsHolder:
Siddharth Kulkarni; institutionID: Bombay Natural History Society (BNHS), Mumbai;
institutionCode: BNHS; collectionCode: Sp
b. scientificName: Tylorida sataraensis; taxonomicStatus: accepted; kingdom: Animalia;
phylum: Arthropoda; class: Arachnida; order: Araneae; family: Tetragnathidae;
taxonRank: species; genus: Tylorida; specificEpithet: sataraensis;
scientificNameAuthorship: Kulkarni, 2014; continent: Asia; country: India; countryCode:
IN; stateProvince: Maharashtra; municipality: Satara; locality: Chalkewadi;
verbatimLocality: Chalkewadi sada; verbatimElevation: 1078 m;
georeferenceVerificationStatus: Verified by collector; samplingProtocol: Hand picking;
eventDate: 04/19/2014; habitat: Rocky plateaus; individualCount: 2; sex: 2 males;
lifeStage: Adults; catalogNumber: BNHS Sp. 120-121; recordedBy: S. Kulkarni and A.
Vartak; identifiedBy: Siddharth Kulkarni; dateIdentified: 08/05/2014; language: en;
rightsHolder: Siddharth Kulkarni; institutionID: Bombay Natural History Society (BNHS),
Mumbai; institutionCode: BNHS; collectionCode: Sp
c. scientificName: Tylorida sataraensis; taxonomicStatus: accepted; kingdom: Animalia;
phylum: Arthropoda; class: Arachnida; order: Araneae; family: Tetragnathidae;
taxonRank: species; genus: Tylorida; specificEpithet: sataraensis;
scientificNameAuthorship: Kulkarni, 2014; continent: Asia; country: India; countryCode:
IN; stateProvince: Maharashtra; municipality: Satara; locality: Kaas; verbatimLocality:
Kaas sada; verbatimElevation: 1123 m; georeferenceVerificationStatus: Verified by
collector; samplingProtocol: Hand picking; eventDate: 02/14/2014; habitat: Rocky
plateaus; individualCount: 2; sex: 2 males; lifeStage: Adults; catalogNumber: BNHS Sp.
122 & 123; recordedBy: S. Kulkarni; identifiedBy: Siddharth Kulkarni; dateIdentified:
08/05/2014; language: en; rightsHolder: Siddharth Kulkarni; institutionID: Bombay Natural
History Society (BNHS), Mumbai; institutionCode: BNHS; collectionCode: Sp
Description
Total length: 8.1-9.7; carapace: 3.91-4.27 long, 2.31-2.48 wide; abdomen: 3.89-4.01
long, 1.78-1.89 wide. Body pattern in male similar to its female (Kulkarni 2014) (Figs 6,
7). Cephalothorax. Cephalic and thoracic region in same plane. Lateral eyes encircled
black, placed on prominent tubercles. AME separated by its diameter, PME less than
its diameter. Smooth black pubescence on carapace. Thoracic region margined dark
black. Chelicerae brown, long with three promarginal and four retromarginal teeth.
Labium brown, semi-circular with slight corrugations; endites longer than wide, with
wider proximal edge. Sternum brown, overall heart-shaped with straight margin at coxa
II and folded inwards at coxae III and IV. Legs yellow coloured, femora black distally.
Abdomen oval shaped, narrower than cephalothorax and slightly overlapping thoracic
region when viewed laterally. Dorsum covered with greenish pubescence; venter black
with thick yellow lines on the margin, sparsely covered with silver specks and whitish
pubescence.
Description of male Tylorida sataraensis Kulkarni, 2014 (Araneae ... 3

Figure 1.
Right palp, dorsal view of (a) T. ventralis and (b) T. sataraensis (Scale = 1mm).
Figure 2.
Right palp, ventral view of (a) T. ventralis and (b) T. sataraensis (Scale = 1mm).
Figure 3.
Conductor and embolar tip in (a) T. ventralis and (b) T. sataraensis (Scale = 0.5 mm).
4Kulkarni S, Lewis T

Cymbial dorso-basal process is shorter than half the cymbial width and perpendicular
to cymbium longitudinal axis. Embolar base roughly circular. Long macrosetae on
palpal metatarsus measuring half times its length. Morphometry of palpal organs is
given in Table 1.
Remarks: The variation in body size and patterns in T. ventralis (see Jäger and
Praxaysombath 2009) may be confused with T. sataraensis. Male palp and female
epigyne examination can confirm the species identity. Furthermore, we found webs of
T. sataraensis exclusively above and across stream water surfaces whereas webs of T.
ventralis were found either adjacent to stream margins or away, among low vegetation;
both observed in different localities.
Figure 4.
Macroseta on palpal patella in Tylorida sataraensis.
Figure 5.
CDBP pointed in (a) T. ventralis and (b) T. sataraensis (Scale = 1mm).
Description of male Tylorida sataraensis Kulkarni, 2014 (Araneae ... 5

Character Tylorida ventralis Tylorida sataraensis
Macroseta on palpal patella No Yes
Palpal femora: length to width ratio 9 10-10.5
Tibia length to width ratio 1.15 1.5
Figure 6.
Habitus dorsal view of Tylorida sataraensis.
Figure 7.
Habitus ventral view of Tylorida sataraensis.
Table 1.
Morphometry for diagnosis of male T. sataraensis (N=6) compared to T. ventralis (N=6).
6Kulkarni S, Lewis T

Paracymbium to CDBP ratio (range) 0.60-0.75 0.95-1
Embolus: CDBP ratio 0.5 0.97-1
Total size (range in mm) 6.17-7.58 8.1-9.7 (larger species)
Leg I length to carapace length ratio (range) 10.2- 11.71 6.9-7.6
Diagnosis
Tylorida sataraensis is closely related to T. ventralis but distinguished from all
described Tylorida species by the following combination of characters: less swollen
tegulum ventrally, longer embolar tip (Figs 1, 2, 3), presence of macroseta on palpal
patella (Fig. 4). CDBP erect and pointed in T. sataraensis but slightly bent upwards
near tip in T. ventralis (Fig. 5). Paracymbium arrow shaped, lateral margins curved,
distal end folded inwards in former but with straight lateral margins and distal edge
bulged at one end in latter species. Overall, T. sataraensis is large sized species than
T. ventralis (Table 1).
Distribution
India, Maharashtra, Satara.
Discussion
A total of 309 T. sataraensis were observed from three sample surveys across eleven
rocky outcrop sites in the northern Western Ghats (Table 2, Fig. 8). Tylorida sataraensis
was observed only on high altitude plateaus (≈1100 m ASL) inhabiting surface waters of
streams shaded by marginal vegetation. All spiders (N=309) were encountered in webs
constructed across the channel width of streams. Orb webs were built with silk lines
attached to marginal vegetation and laterite rocks. Webs were built high enough (up to 60
cm) and wide enough (up to 100 cm) to avoid fluctuations in stream water levels.
Observationally, laterite rocks seemed to be the preferred anchor points for web
construction (N=309) and such microhabitat features may influence web site selection for
the species. Some specimens (N=56) were also observed hiding on the side of laterite
rocks that faced the stream edge during the monsoon. Spiders that were observed on the
sides of laterite rocks seemed to prefer using cavities in the rock surface (N=37) for refuge
(Fig. 9). Egg sacs (N=12) were laid pre-monsoon, above stream flow, on the side of laterite
rocks (Fig. 10). Spiders escaped into the main flow of stream water when disturbed but
were anchored by a dragline to adjacent laterite rocks that assisted their return to the web.
Air pockets were observed along the body surface of spiders submerged in stream water
(Fig. 11) and it is possible such adaptation might assist them to resurface. Twenty spiders
were timed underwater displayed significantly different submersion times (t = 5.78, df = 19,
Description of male Tylorida sataraensis Kulkarni, 2014 (Araneae ... 7

P<0.05). An average of 300 seconds was recorded and the most tenacious remained
submerged for over 829 seconds (>13 minutes) (Suppl. material 1).
Survey Males Females Juveniles ∑
Jan-14 8 31 64 103
Jun-14 10 18 56 84
Sep-14 39 64 19 122
∑ 57 113 139 309
Table 2.
Abundance from three sample surveys of T. sataraensis.
Figure 8.
Points showing surveyed rocky outcrop sites in Northern Western Ghats, of which sighting of
T. sataraensis in red square - Chalkewadi and red circle - Kaas.
Figure 9.
Tylorida sataraensis in a cavity of laterite boulder.
8Kulkarni S, Lewis T

Conservation status
The greatest current threats to rocky plateau areas continue to be habitat degradation,
destruction and direct removal of laterite rocks for construction purposes (Watve 2013).
Among those threats observed in the study area, loss of vegetation cover and removal of
laterite rocks are likely to be direct threats to T. sataraensis. Such microhabitat
degradation, if permitted to continue, could reduce the amount of shaded areas and alter
the micro-strata required by the species for web construction. Gradual loss of marginal
vegetation along streams could also displace spiders and reduce available microhabitat
across sites. Where these threats occur, spiders do congregate in patchy pockets where
shade is optimal. Whether this is a natural clustering of population or a response to threats/
impacts remains unknown. If such marginalisation of populations are caused by
anthropocentric impacts it could potentially fragment populations in the longer term. Local
use of stream water for agricultural purposes is also reducing flow levels across some
sites. This action could also affect distribution of spiders across each site and alter niche
availability.
Figure 10.
Female Tylorida sataraensis on an egg sac.
Figure 11.
Air trapped on spider body surface.
Description of male Tylorida sataraensis Kulkarni, 2014 (Araneae ... 9

In total, ten plateaus were surveyed across the breadth of the northern Western Ghats.
From these sites, T. sataraensis has been observed only at Chalkewadi (type-locality) and
Kaas plateaus. Combined these plateaus span an area of only 69 Km . Therefore, in the
interests of conservation, we collected only five adult males during the three years survey.
Dispersal of these spiders on Chalkewadi and Kaas was observed only during the
monsoon period when streams swell and become connected. The extent of occurrence
(EOO <100 Km ) and area of occupancy (AOO <10 Km ) for T. sataraensis appears to be
fragmented. Based on its current known distribution, the species would likely fall under
IUCN status Critically Endangered (CR) following Criteria B1ab(iii)+ B2ab(iii) (IUCN 2012).
The detection of this species so far, at just two localities in the northern Western Ghats,
and the observed threats recorded here, suggest that T. sataraensis deserves urgent
efforts to conserve it.
Acknowledgements
Thanks to Fernando Alvarez-Padilla, Hemant Ghate, Gustavo Hormiga, David Court, Akio
Tanikawa, Neelesh Dahanukar for suggestions and helpful discussions, Atul Vartak for
sharing photographs, Vishal Deshpande for collecting the first specimen from Chalkewadi,
Vinayak Patil for a T. ventralis male specimen, Sameer Padhye, Priyanka Kulkarni for help
in preparing plates and Swara Yadav for assitance during the last field survey.
Author contributions
Siddharth Kulkarni was involved in the field work, examining specimens and manuscript
writing, Todd Lewis was involved in the data analysis and manuscript writing.
References
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(Arachnida: Araneae). Acta Arachnologica 58: 27‑51.
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management. Journal of Threatened Taxa 5 (5): 3935‑3962. DOI: 10.11609/
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Supplementary material
Suppl. material 1: Submersion time of T. sataraensis under water (N=20)
Authors: Siddharth Kulkarni and Todd Lewis
Data type: Time records
Filename: supp1.xlsx - Download file (10.75 kb)
Description of male Tylorida sataraensis Kulkarni, 2014 (Araneae ... 11