Rediscovery of Hypselobarbus pulchellus , an endemic and threatened barb ( Teleostei : Cyprinidae ) of the Western Ghats , with notes on H . dobsoni and H . jerdoni

1 Flat L’, Sri Balaji Apartments, 7th Main Road, Dhandeeswaram, Velachery, Chennai, Tamil Nadu 600042, India 2 Department of Fisheries Microbiology, College of Fisheries, Yekkur, Mangalore, Karnataka 575002, India 3 Department of Applied Zoology, Mangalore University, Mangalagangothri, Mangalore, Karnataka 574199, India 1 jdmarcusknight@yahoo.co.in (corresponding author), 2 winrai@yahoo.com, 3 kevinroni@yahoo.com


INTRODUCTION
The enigmatic large barbs of the genus Hypselobarbus Bleeker, 1860 have always interested ichthyologists with several studies being carried out on their phylogeny and systematics (Mukerji 1931;Raj 1941;Jayaram 1997;Arunachalam et al. 2012;Pethiyagoda et al. 2012;Yang et al. 2012;Ali et al. 2013;Knight et al. 2013a,b).However, the identity of several species within this genus continues to remain ambiguous, with certain species presumed extinct due to the absence of any verifiable records since their description.One such poorly known species is Hypselobarbus pulchellus (Day, 1870), which has been categorized as 'Critically Endangered' (possibly Extinct) in the IUCN Red List of Threatened Species (Devi & Ali 2011) as a result of very few verifiable records since its description, including from the type locality, South Canara (Menon 2004).
There is also a considerable amount of taxonomic ambiguity surrounding the identity of H. pulchellus, with a few authors considering it as a junior synonym of either H. dobsoni or H. jerdoni (Hora & Misra 1942;Jayaram 1991;Talwar & Jhingran 1991;Jayaram 1999;Daniels 2002), while others suggesting that it is very difficult to distinguish H. pulchellus from H. dobsoni and H. jerdoni (Devi & Ali 2011).
Like Hypselobarbus pulchellus, H. dobsoni is also a poorly known and documented species classified as 'Data Deficient' in the IUCN Red List (Raghavan & Ali, 2011).Recently, there has been a speculation of the possibility of undescribed species being concealed within the genus Hypselobarbus (Arunachalam et al. 2012).This makes it imperative that the taxonomic identity and distribution of some of the already known species (for e.g., H. pulchellus, H. jerdoni and H. dobsoni) be cleared before additional species are described under this genus.Taxonomic studies on the genus Hypselobarbus is also imperative since most known species are threatened (Dahanukar et al. 2011), and their identities have to be cleared, before their populations decline further leading to possible extinction.
Recent surveys in South Canara = Dakshina Kannada led to the collection of specimens that matched the description of H. pulchellus.In this paper, we record this finding, redescribe this poorly known species and clear its taxonomic ambiguity vis-à-vis H. dobsoni and H. jerdoni.

MATERIALS AND METHODS
The materials used in the present study is based mostly on specimens collected during recent fieldwork in the Tunga, Sita and Netravathi rivers in southern Karnataka, and deposited in the Collections of the Zoological Survey of India, Southern Regional Centre, Chennai (ZSI/SRC) and the private collections of J.D. Marcus Knight (MKC).Quantification of characters follows Kottelat (2001).Measurements were taken using a digital caliper to the nearest 0.01mm and rounded to 0.1mm, except for measurements of standard length, which were measured with a ruler to the nearest 1mm.Subunits of the head are expressed in proportions of head length (HL).Numbers in parenthesis after a count denote the frequency of that count.Specimens were examined and/or dissected under a Magnüs binocular dissection micropcope.Osteological procedures follow Miranda & Escala (2005).Photographs were taken with an Olympus SP570 UZ digital camera using supermacro mode.Specimens of H. pulchellus and H. jerdoni were collected from Dakshina Kannada = South Canara, their type locality and are topotypes.In the original description Day (1876) does not provide the type locality for H. dobsoni but Day (1878) mentions that, "Deccan from whence Dr. A.J. Dobson sent me specimens; I likewise obtained this species at Kurnool, in September, 1866, and also at Poona."As Kurnool lies on the banks of Tungabhadra River, in the present study we used H. dobsoni from Tunga River as comparative material.Photographs of the syntypes of both H. jerdoni and H. dobsoni from the Australian Museum, Sydney (AMS) and the photograph of a dry skin of H. pulchellus deposited by F. Day in the Natural History Museum, London (BMNH) were used to compare the general body shape and the lateral line scale count.

Colouration
In life, dark grey above and light grey below with a silver or bronze coloured band running across the length of the body two scales high, which include the lateral line scale row and one scale row above it.Head silvery white and all fins dusky grey (Image 1A).Formalin-fixed and alcohol-preserved specimens are dark grey with the lateral band becoming white in colour.All fins dark grey (Image 1B).The light coloured band running along the lateral line is also clearly perceivable in the dry skin mount of H. pulchellus in the Natural History Museum, London (BMNH 1889.2.1.4328)(Image 1D).

Distribution
Hypselobarbus pulchellus is currently known from Sita and Tunga rivers, Shimoga in the South Canara region of the southern Western Ghats.

DISCUSSION
Barbus (Barbodes) pulchelus currently designated to the Genus Hypselobarbus (Rainboth 1989;Menon 1992;Arunachalam et al. 2012;Yang et al. 2012;Knight et al. 2013b) was described by Day (1870) from South Canara, India (Day 1878).Though there have been sporadic reports of this species from the Western Ghats (Rajan 1955;David 1956;David et al. 1967;David et al. 1970;David & Rajagopal 1975;Mohanta et al. 2008), its identity was either considered unclear (Devi & Ali 2011) or the species was considered a synonym of either H. dobsoni or H. jerdoni (Hora & Misra 1942;Jayaram 1991;Talwar & Jhingran 1991;Jayaram 1999;Daniels 2002).As all these reports were either a part of natural history or fishery studies, they lacked the description or the voucher specimen of the fish identified as H. pulchellus, thereby providing no clarity on the identity of this enigmatic barb.This lack of information and clarity on its identity eventually led to H. pulchellus being categorized as a 'Critically Endangered' (and possibly Extinct) (Devi & Ali 2011).Even the description of H. pulchellus in a recent report (Shrivana 2013) pointed towards H. dobsoni instead, highlighting the fact that there is significant confusion on the identity of these species.Moreover, Arunachalam et al. (2012) while highlighting the possibility of undescribed species being concealed within this genus, overlooked both H. dobsoni and H. pulchellus in their work.As H. pulchellus has been listed as 'Critically Endangered' (possibly Extinct) (Devi & Ali 2011) it is important to fill in knowledge gaps on its identity and status, before additional species are described under Hypselobarbus and the already extant species are forgotten in time.
Interestingly, Jayaram et al. (1982) considered H. pulchellus as a valid species and remarked that though Hora & Misra (1942) synonymised H. pulchellus with H. jerdoni, it could be clearly distinguished from the latter by a higher lateral line scale count of 30-35 and the relative length of the dorsal fin.During the course of the study, one specimen of H. pulchellus collected by Jayaram (ZSI/SRC F 8753) from Tunga River, Shimoga, Karnataka was examined.Similar to the other specimens of H. pulchellus collected from Sita River, Karnataka, the specimen from Tunga River, Shimoga collected by Jayaram had 33+2 lateral line scales.Moreover, H. pulchellus can be distinguished from H. jerdoni based on a shorter dorsal fin length of .1 % SL) as observed by Jayaram et al. (1982).
Hypselobarbus pulchellus can also be distinguished from H. micropogon, H. periyarensis and H. dubius by having its last simple dorsal ray weak and articulated vs. strong osseous (Jayaram 1991).It can be distinguished from H. curmuca and H. canarensis by a lower lateral line scale count of 32-34+1-2 (vs.41-44) and by the presence of two pairs of barbels (vs.one pair of barbels in H. curmuca) (Knight et al. 2013b) .
It is relevant to note that Hypselobarbus dobsoni and H. jerdoni were also considered synonyms by certain authors (Jayaram 1991;Talwar & Jhingran 1991;Jayaram 1999;Daniels 2002).However, these two species can be clearly distinguished from each other by H. dobsoni having grey or pale yellow fins vs. H.jerdoni having bright orange or red fins.Hypselobarbus dobsoni can further be distinguished from H. jerdoni based on a lesser body depth of 28.7-31.8% SL (vs.32.9-38.6 % SL); greater body width of 18.0-19.3% SL (vs.15.0-16.4% SL); greater caudal peduncle length of 15.0-16.4% SL (vs.11.2-14.2% SL); lesser caudal peduncle depth of 14.3-15.4% SL (vs.16.0-18.4% SL); shorter dorsal fin length of 21.5-25.2% SL (vs.26.4-30.1 % SL); shorter anal fin length of 16.3-19.0% SL (vs.20.4-21.3 % SL) and shorter pelvic fin length of 16.9-19.4% SL (vs.20.7-22.6 % SL).Day (1870) based his original description of H. pulchellus on a single stuffed specimen and mentioned 30 lateral line scales.Later Day (1878) redescribed the species based on two specimens and reported a lateral line scale count as 30-32.Even though Day (1878) does not mention whether the specimens were stuffed or not, the original description (Day 1870) was based on stuffed specimens and scale loss in stuffed specimen is quite inevitable.However, the specimens examined in this study had 32-34+1-2 lateral line scales.It is highly probable that one or two scales on the caudal fin base could have fallen off in the specimen that Day (1870) used for the original description.Moreover, the dry skin mount of H. pulchellus at the National History Museum, London (BMNH 1889.2.1.4328)does appear to have more than 32 lateral line scales.All other characters, including the unique colour pattern consisting of the silver or bronze coloured band running across the length of the body fit the description as provided by Day (1870Day ( , 1878)).
Habitat loss as a result of dams and hydro-electric projects, together with other anthropogenic factors such as unmanaged exploitation often through the use of destructive fishing practices could be a probable reason for the decline in the population of these barbs (Devi & Ali 2011).However, 'Wallacean shortfall' also has a part in certain species being presumed extinct (Knight 2010) which in this case is evident from the record of H. pulchellus from its type locality from where it was 'presumed' extinct.