Range extension of Oziothelphusa mineriyaensis Bott , 1970 ( Decapoda , Gecarcinucidae ) in North Central Province , Sri Lanka

The known distribution in Sri Lanka of the endemic freshwater crab Oziothelphusa mineriyaensis Bott, 1970 was limited to 2 known localities in the dry zone. In this study of the distribution of this species in the North Central Province of Sri Lanka, we identified 5 new localities. Our findings expand the extent of occurrence from 168 km2 to 1467 km2. Our new records are 62 km from the type locality and up to 89 km from the previous records in Anuradhapura District and 20 km from previous record in Polonnaruwa District. These data provide important new information needed for the conservation of this endangered species in Sri Lanka.


Introduction
Freshwater crabs in Sri Lanka are one of the faunal groups with the highest rate of endemism, with 51 endemics of the 52 species (Bahir et al., 2005, Udagedera et al. 2015).Among these species, the genus Oziotelphusa Müller, 1887 is found mostly in open habitats in India and Sri Lanka.Ten of the 15 species of Oziotelphusa are endemic to Sri Lanka, and all of them are included in the IUCN Red List (Bahir et al. 2008, Bahir andYeo 2005).The study by Bahir et al. (2005) reported 80% of the freshwater crab species to be restricted to wet zone (annual rainfall >2500 mm) with very limited distribution in the dry zone (annual rainfall <2000 mm).The North Central Province, situated in the dry zone of Sri Lanka, harbours only 4 Oziothelphusa species (O.ceylonensis (Fernando, 1960), O. hippocastanum (Müller, 1887), O. mineriyaensis Bott, 1970, andO. ritigala Bahir &Yeo, 2005) of the 52 species on the island (Ng and Tay 2001).
Oziothelphusa mineriyaensis (Fig. 1) is a freshwater crab endemic to Sri Lanka.This species is typically found near rice fields, and on the embankments of water holes, streams, and irrigation canals (Bahir et al. 2005, Bahir andYeo 2005).Morphologically, O. mineriyaensis is most similar to O. ritigala and O. intuta in its carapace characteristics, but the gonopods differ (Bahir and Yeo 2005).
The type locality of O. mineriyaensis is Minneriya  Bahir andYeo 2005, Bahir et al. 2008).Here, we report 5 new localities for O. mineriyaensis from the North Central Province of Sri Lanka, which add significantly to the known geographic distribution of this species.New records of endemic species, such as reported here, are important for biodiversity conservation.

Methods
The study was conducted in all areas, including both protected areas (established by the Sri Lanka Department of Wildlife Conservation) and unprotected areas (paddy fields, irrigation canals, and other open areas) of the North Central Province.This study was as a part of a survey, conducted from 2012 to 2014, to document the current distribution and diversity of the freshwater fauna in 2 districts (Anuradhapura and Polonnaruwa) of the North Central Province.The specimens were hand collected (n = 8) using the Rapid Surber sample method (Magana et al. 2012) and counts were taken using the visual encounter method (Patton 2010) in selected locations.
All the collected specimens were preserved in 70% isopropyl, given voucher numbers, and deposited at the zoological laboratory, Faculty of Applied Sciences, Raja-rata University of Sri Lanka (Table 1).The Department of Wildlife Conservation in Sri Lanka gave permission for specimen collection under permit number WL/3/2/73/12 to 14. Locations were recorded using the Garmin GPS-MAP 64s GPS receiver (Garmin International, USA).Measurements of carapace width (CW), carapace length (CL), abdomen width (AW), propodus length (PL)/left (L), propodus height (PH)/L, propodus length (PL)/right (R) and propodus height (PH)/R) (Table 1) were taken to the nearest 0.02 mm using a vernier caliper (Tricle Brand, Shanghai, China).
The previously published distribution records of O. mineriyaensis were taken from (Ng and Tay 2001), (Bahir and Yeo 2005), and Bahir et al. (2008) and used to prepare the distribution map (Fig. 2), along with our new records, using ArcGIS version 10.0 (ESRI, USA).

Results
The morphological identification (Fig. 3) of O. mineriyaensis was made based on (Ng and Tay, 2001) and (Bahir and Yeo 2005).This species was differentiated from the O. ritigala and O. intuta by the character of the male first gonopods (G1), which are distinctly broader terminally, box shaped in dorsal view, and with the outer margin of the lateral basal half of the G1 subterminal segment distinctly swollen in lateral view (Bahir and Yeo 2005).These distinctive characters, including other morphological characters, confirmed that our specimens were O. mineriyaensis (Fig. 3).
During this survey we recorded O. mineriyaensis at 5 new localities in the North Central Province: 51 individuals at seasonal streams, open areas, and forested areas of the Mihintale Sanctuary; 17 individuals at Galkulama under forest patches, 24 from paddy fields and irrigation canals from Eppawala; 13 individuals at Nochchiyagama from the paddy fields, slow moving seasonal streams, and the irrigation canals; and 6 individuals from irrigation canals at Polonnaruwa New Town (Table 1, Fig. 2).Eight individuals (4 males and 4 females) were examined to confirm the species identity, and 113 individuals of O. mineriyaensis were recorded in this study.
, 080°54ʹ E), near Polonnaruwa in North Central Province, and its known distribution was until now limited only to 2 location (Anuradhapura, North Central Province) other than the type locality(Ng and Tay 2001,