A NEW FISH SPECIES OF THE GENUS BARILIUS ( CYPRINIDAE : RASBORINAE ) , FROM RIVER SIANG

Arunachal Pradesh is known as global biodiversity hotspot in Eastern Himalaya and located in the transition zone between the Himalayan and Indo-Burmese region. The total geographical area of the Arunachal Pradesh is 83,743 km2, which is predominantly hilly and mountainous, and largely covered with extremely varied and dense vegetation! forests, crisscrossed by six major rivers and their tributaries (Kaul and Haridasan, 1987; FSI 2000; Kalita and Haridasan, 2001). These habitats carry fairly large populations of faunal elements belonging to various groups of invertebrates and vertebrates (Editor-Director 2006 a&b; Kumar and Ramakrishna 2009). During last one decade several new species of vertebrates and invertebrates have been discovered from the state (Borang et al. 2005; Datta et al. 2008; Kumar and Ramakrishna, 2009; Kumar et al., 2005; Mishra and Datta, 2007). As per records of Zoological Survey of India (ZSI), fish fauna of Arunachal Pradesh comprises of 143 species under 61 genera, 21 families and 8 orders (Editor-Director, 2006a). It includes 50 new records from the state. The family Cyprinidae forms the largest group with 65 species followed by Homolopteridae (17 species), Sissoridae (12 species), Bagridae (7 species), Channidae and Cobitidae (6 species each) and the rest with one, two or three species. Of the 50 new records, 12 fish species are recorded exclusively from the state of Arunachal Pradesh. Most of the fishes of hill streams belong to the Genus Barilius. Review of the literature reveals that in most cases the information on systematics of these taxa was provided only up to generic level. Howes (1980) reported the details of lateral line as complete, incomplete or absent. Nevertheless all the species either reported from India or adjoining countries has complete lateral line but none reported the absence or presence of interrupted lateral line at the species level. Similarly all seven species reported from the State of Arunachal Pradesh (Nath and Dey 2000; Sen 2006) showed the presence of complete lateral line.


INTRODUCTION
Arunachal Pradesh is known as global biodiversity hotspot in Eastern Himalaya and located in the transition zone between the Himalayan and Indo-Burmese region.
The total geographical area of the Arunachal Pradesh is 83,743 km2, which is predominantly hilly and mountainous, and largely covered with extremely varied and dense vegetation!forests, crisscrossed by six major rivers and their tributaries (Kaul and Haridasan, 1987;FSI 2000;Kalita and Haridasan, 2001).These habitats carry fairly large populations of faunal elements belonging to various groups of invertebrates and vertebrates (Editor-Director 2006 a&b;Kumar and Ramakrishna 2009).During last one decade several new species of vertebrates and invertebrates have been discovered from the state (Borang et al. 2005; Datta et   al. 2008; Kumar and Ramakrishna, 2009; Kumar et al.,  2005; Mishra and Datta, 2007).As per records of Zoological Survey of India (ZSI), fish fauna of Arunachal Pradesh comprises of 143 species under 61 genera, 21 families and 8 orders (Editor-Director, 2006a).It includes 50 new records from the state.The family Cyprinidae forms the largest group with 65 species followed by Homolopteridae (17 species), Sissoridae (12 species), Bagridae (7 species), Channidae and Cobitidae (6 species each) and the rest with one, two or three species.Of the 50 new records, 12 fish species are recorded exclusively from the state of Arunachal Pradesh.
Most of the fishes of hill streams belong to the Genus Barilius.Review of the literature reveals that in most cases the information on systematics of these taxa was provided only up to generic level.Howes (1980) reported the details of lateral line as complete, incomplete or absent.Nevertheless all the species either reported from India or adjoining countries has complete lateral line but none reported the absence or presence of interrupted lateral line at the species level.Similarly all seven species reported from the State of Arunachal Pradesh (Nath and Dey 2000;Sen 2006) showed the presence of complete lateral line.
In the present investigation we are reporting a new species of fish of genus Barilius from D'Ering Memorial Wildlife Sanctuary, Eastern Arunachal Pradesh.(Fig. 1) In this regard it may be mentioned that the support for the new species has been thoroughly investigated with all known species (including all synonymies) of the genus Barilius so far reported from the region and adjoining areas.Further, it may be mentioned that Tilak et al. (1984) and Talwar & Jhingran (1991) reported of sexual dimorphism pertaining to few characters like coloration of the body, fan shaped paired fins, body size in synonymies of B. bendelisis.When compared with the reported species, B. arunachalensis it revealed many interesting and new characters which were found sufficient to authenticate the reported species as new to science particularly in respect of barbels (totally absent), lateral line (incomplete, ceases at the 35 th scale), lateral line scales (with single large spots and a few bilobed spots), dorsal fin (fan shaped enclosed in a sheath with strong rays), snout (deeply humped), 'V' shaped band one on each side of gill opening, caudal fin (unequal).Jopong and Balun formed between Siang River and its tributary Sibya River (Fig. 2 and Fig. 3).Both the rivers are divided into streams, which intersect the sanctuary and form several smaller islands also.The topography of these islands changes from time to time depending upon the season, rainfall and flooded water.The surrounding area of the sanctuary is mainly composed of agriculture fields and thick forests.The main agriculture crop is paddy, while thick forest composed of mixed vegetation such as Bombax ceiba, Albizzia procera, Dipteria wallichii, Talauma hodgsonii, Daubanga grandiflora, Solanum torvum and Ficus dumosa etc.The sanctuary support a large number of endangered, rare aquatic and terrestrial species of animals such as White-winged Duck, Bengal Florican, Gangetic Dolphin, Tiger, Hispid Hare and some rare species of invertebrates (Kumar, 2009).

MATERIALS AND METHODS
The fauna of the sanctuary has not been documented properly.With reference to the ongoing research project of the Zoological Survey of India for Rec.zool.Surv.India the documentation of fish fauna of Arunachal Pradesh, a field survey was undertaken w.e.f.03.10.2006 to 23.10.2006.During the survey different localities of DWS and surrounding areas were visited.Some fish specimens were also collected for identification and photographs were taken, from outside the sanctuary areas.During the survey on 07.10.2008, an interesting species was seen in the shallow water of Agari River mouth (Fig. 2).Few specimens were collected (about 8 of them) with the help of a local fishing person and photographed with scale (Fig. 4).Preliminary identification revealed that this species had some peculiar features and assumed that it may be new to science.On 08.10.2008, while surveying the southwest side of Jopong Island, the same species was seen in the shallow water streams in good number (about 11 individuals were seen).For confirmation and identification two of them were trapped, photographed and released immediately at the same place of trapping.
Morphometric measurements and counts were made with dial calipers and recorded.The measurements of head length and body parts has been presented as proportion of standard length (SL).The subunits of head are presented as proportion of head length (HL).Counts and measurements were made on the left side of the specimen whenever possible.The system of classification of fish followed is after Jayaram (1999).

RESULTS
This new species differs from the other reported species of the Genus Barilius on various scores viz.
(1) On the numbers of fin rays (D.i.7, P.ii.ll,V.i.8, A.ii.On account of the above mentioned specific characteristics, the species has therefore been described 3.

5.
as a new species of the Genus Barilius.However while 6. describing the new species, an attempt has been made   Besides, the species under report (B.arunachalensis) has also been compared with the valid species of the Genus Barilius and has been shown in Table -2.The distinguishing features in regard to the Barilius arunachalensis strongly supports for the establishment as a new species.From the comparative chart it could also be revealed that the Barilius arunachalensis Sp. nov.has a close affinity with Barilius bendelisis except for the absence of barbels, body coloration, lateral line incomplete, lips unequal, dorsal fin fan shaped supported with strong rays enclosed in a sheath, cleft of mouth does not reach orbit, snout deeply humped, lateral line scales with single large spots and a few bilobed spots, 'V' shaped band on each side of gill opening, caudal lobe unequal justify for the separation of the reported fish as a new species.

DISTRIBUTION
The fish samples were collected from the Agari River mouth just outside the D'Ering Memorial Wild Life Sanctuary through which passes river Sibya forming one of the tributaries of a major river Siang.The fish specimens were also seen inside the sanctuary at the south west of Jopong Island.The Sanctuary is located adjacent to the Pasighat town, the Headquarters of East Siang district of Arunachal Pradesh.The location of the collection centre is at an altitude of 160 m (msl).

EIYMOLOGY
The species Barilius arunachalensis is named after the state of Arunachal Pradesh.One of the authors namely Anil Kumar collected the fish specimens during his field survey to D'Ering Memorial Wildlife Sanctuary & its adjacent areas.

DISCUSSION
The new species Barilius arunachalensis to some extent has a close resemblance with Barilius bendelisis: (i) Presence of prominent tubercles on snout & lower lip (versus tubercles small and poorly developed in Barilius bendelisis) (ii) Dorsal fin ray (i.7), Pectoral (ii.11), Ventral (i.8), Anal (ii.8) (versus D. ii. 7, A.ii.iii.7-8, P.i.14, V.i 8 in Barilus bendelisis) (iii) Lateral line incomplete and ceases at 35th scale (versus Lateral line scales 40-45 in B. bendelisis); (iv) Dorsal fin fan like (versus dorsal fin not fan like in B. bendelisis of Day, 1878;Tilak et aI., 1984;Talwar & Jhingran, 1991).(v) Each scales with oval spots at dorsal side and diamond shaped at the ventral, and lateral line scales with large single spots and a few bilobed spots ((versus lateral line scales with two spots in B bendelisis of Day, 1878;Tilak et al., 1984;Talwar & Jhingran, 1991).Tilak et a1.(1984) and Talwar & Jhingran (1991) reported of sexual dimorphism pertaining to coloration of the body, fan shaped paired fins, body size of synonymies of B. bendelisis.When compared with the reported species, B.arunachalensis it was found to vary in all respect as pointed out in paragraph (1) as above, i.e. barbels totally absent, lateral line incomplete, lateral line scales with single large spots and a few bilobed spots, 'V' shaped band on each side of gill opening, caudal fin with a prominent streak at the bifurcation of caudal lobe and caudal fin unequal.
The diagnostic features purported in Table-l also distinctly shows that the species under report, Barilius arunachalensis could be readily separated from all the reported species as well as the synonymies of the Genus Barilius (Day, 1878; Talwar & Jhingran, 1991;  Menon, 1999; Jayaram, 1999; Vishwanath & Manoj   Kumar, 2002).
The discovery of the new species (Barilius arunachalensis) from the D'Ering wildlife Sanctuary of Arunachal Pradesh has thrown a new light that the sanctuary offers a safe habitat and in no way the fish stands threatened from external interferences.Thus the sanctuary is one of the noble examples of in-situ conservation of fauna and flora of the region.The collection of live species within the sanctuary is not legally permitted hence only a few samples of the present species were collected from outside the sanctuary.However, the continuity of the studies shall be kept in progress so that any variability of the new species could be further observed, if any.
AREA AND HABITAT D'Ering Memorial Wildlife Sanctuary (hereafter DWS) is located in the eastern Arunachal Pradesh and one of the bio-diversity rich areas of the state.It was notified as Lali Wildlife Sanctuary in 1978 vide notification no.FORJ284178/2 dated 23-08-1978.Later on it was named as Daying Ering Memorial Wildlife Sanctuary vide notification no.CWL/37/83/D/T/4524- 54 dt.27-10-1986.The total area of sanctuary is about 190 km2 including aquatic area of Siang River.The sanctuary located between 95°22' to 95°29' E and 27°51' to 28°05' N, and divided into three ranges namely Anchalghat, N amsing and Borguli.The sanctuary area mainly consists of two types of habitats.(i) Most of the land area (about 75%) is alluvial grassland and semi evergreen forest patches covering the rest (ii) While the aquatic area covering the sanctuary proper comprises of two major islands i.e.
8, C.18); shape of dorsal fins, fan like supported by strong and robust branched rays embedded in a muscular tough skin like pad.(2) Snout and lower lip beset with rough, prominent tubercles.(3) Snout deeply humped.Nostrils with prominent nares.(4) Mouth upturned, lips unequal and gape of mouth does not reach the orbit.

Figure 1 :Figure 2 :
Figure 1 : Map of the D'Ering Memorial Wildlife Sanctuary, showing the study sites.

Figure 3 :
Figure 3 : Photograph is showing the general topography and habitat of the fish at Jopong island inside the sanctuary area.

Figure 4 :
Figure 4 : Indigenous method of the fishing in study area.Tribes of the area, mostly use bamboo made conical baskets (as shown in photo) for fish trapping in the minor rivers/ streams for livelihood.

Figure 5 :
Figure 5 : Photograph of the head region of the fish, showing the absence of barbels.

Figure 6 : 1 Figure 8 : 17 Figure 9 :
Figure 6 : Showing the physical structure and number of dorsal fin rays.

Table 2 :
Comparative account is showing the distinction between Barilius arunachalensis and the allied general species of the sub-family Rasborinae.
& blotches.Dorsal fin advance to Anal.Dorsal fin dark grey with pinkish edge others yellow.The fish attains a length of 15 em.
e. -Dorsal & Anal fins with spines.Body with ( of Arun Kumar and 14-16 dark lateral bands.(NoBariliusspecies so Tombi Singh, 2000)far reported with spines thus needs to be separated).

Table 2 :
Cont'd.grateful to the Director, ZSI, Kolkata, to grant the permission for field survey and the Officerin-Charge, APFS, ZSI, Itanagar, for extending departmental facilities.Our sincere thanks are due to Dr. Ambrish Kumar, Scientist-B, BSI, Itanagar, for the identification of plants and characterization of habitats.Kind support and active cooperation at various levels from the Forest Department of Arunachal Pradesh is Hence not described.Hence not described.Rough tubercles, prominent on snout & lower jaw.Barbels absent.Snout deeply humped.Mouth upturned, gape not reaching orbit.Lips unequal, lower lip slightly longer.Lateral line scales incomplete, ceases at the 35th scale.Dorsal inserted ahead of anal, but nearer to caudal base.Dorsal fin extends to 3 rd ray of Anal.Scales large, cycloid and with oval spots at the dorsal side & diamond shaped spots at the ventral surface and lateral line scales with single large spots and a few bilobed spots.Pectoral tip just reaching ventral fin base.Two broad band almost 'V' shaped on each side behind gill opening.Caudal fin with prominent streak at the bifurcation of the caudal lobe.Longitudinal streak at the dorsal fin and prominent streak at the bifurcation of caudal.Caudal unequal, lower lobe longer.The length of fish recorded upto 16.8 cm. also gratefully acknowledged.Special thanks are due to DFO, D'Ering WL Sanctuary and staff of D'Ering WL Sanctuary namely Shri B. Magu, Range Officer, Mr. Ram Ering, Forester, Mr. Kebiyon Mitkong & Mr. J. N. Terrang, Forest Guard, Mr. Arun Kalita, Boat Driver, and Mr. Tanong Tamir, Mr. Bugeswar Tayang, Mr. Satish Das, Boatman.A local person Mr. Tibang Tayang also helped during survey in Borguli Range and thanks are also due to him.