First Record of Catfish Amblyceps waikhomi (Darshan, Kachari, Dutta, Ganguly, and Das 2016) (Siluriformes: Amblycipitidae) for Nepal from the Singhiya River of Morang District, Eastern Nepal

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Introduction
Te family Amblycipitidae is considered torrent catfshes, having small-bodied inhabiting streams and rivers mostly in southern and eastern Asia [1]. A double fold of the skin on the upper and lower lips, pinnate-like rays on the anterior margins of the procurrent caudal fn rays, the anterior nostril located directly anterior to the base of the nasal barbel, and the epiphyseal commissure of the supraorbital sensory canals situated directly anterior to and not passing through the epiphyseal bar can all be used to identify the genus Amblyceps [2]. Furthermore, Amblyceps species are simply identifed by the existence of the pinnate rays along the median caudal fn rays, a distinguished cup-like skin fap above the base of the pectoral spine, and adipose fn largely separated from the caudal fn [3].

Materials and Methods
Te current Amblyceps species was only found in the Singhiya River in Morang district. It is a perennial river that rises from the edges of Hattimuda, Dulary, and Sundar Haraicha and then roars through Budhiganga municipality and Biratnagar submetropolitan before crossing the border into India from Buddhanagar. It is located at latitude 26.913°N and longitude 87.1570°E (Figure 1), respectively. Te primary use of this river's water is irrigation. Bamboo and coniferous forest make up the majority of the riverside vegetation, and cobbles, pebbles, gravel, and sand make up the majority of the riverbed's substrate.
Only one species of Amblyceps (A. mangois) has been discovered in recent ichthyological surveys of Nepal. Te feldwork was conducted in eastern Nepal's various rivers, including Singhiya, Keshaliya, Lohandra, Ratuwa, and Kankai, from December 21, 2021, to September 5, 2022, using cast nets of various sizes, one with a mesh size of 0.5 cm, a diameter of 5 m, and a weight of 2 kg and another with a mesh size of 2 cm, a diameter of 5 m, and a weight of 4 kg. Environmental factors like water temperature, dissolved oxygen, free carbon dioxide, total alkalinity, total hardness, water velocity, and pH were also measured while fsh were being collected. Te collected specimens were photographed and preserved in 95% ethanol by lowering their heads to shield the caudal fn. Te present species was compared with A. mangois, and we concluded that this represents the new Amblyceps species for Nepal.

Description and Comparison of the Specimens
Te specimen's diagnostic features were examined and measured in accordance with [3,[5][6][7], including standard length, predorsal length, preanal length, prepelvic length, prepectoral length, length of the dorsal fn base, length of the anal fn base, length of the pelvic fn, length of the pectoral fn, length of the caudal peduncle, body depth at the anus, head length, width, and depth, and also, meristic counts of the dorsal, pectoral, pelvic, anal, and caudal fn rays were performed. Te current species has a depressed head, unequal jaws with the lower one being slightly longer, an incomplete lateral line, and a short, laterally compressed body. Te anal fn origin is slightly anterior to the locations of the anus and urogenital openings. Te nasal barbel extends beyond the upper margin of the upper gill opening but does not reach the posterior margin of the opercle. Lips are papillate with a double fold of thickened skin. Te skin on the head, tuberculate, and inner mandibular barbel extends to the base of the pectoral fn. In addition to lacking (or having) strongly developed projections on the proximal lepidotrichia of the median caudal fn rays, A. waikhomi difers (Figures 2 and 3  International Journal of Zoology 3 In fresh conditions, the dorsal and lateral sides of the head and body are deep brownish, and ventrally creamy. Te dorsal fn with six branching rays has a spine and a spinelet. Te dorsal fn spine is smooth, short, and straight, with a sharp point at the distal end. Short and low, joining from the vertical halfway between the anus and anal fn origins, the adipose fn's posterior border is well isolated from the caudal fn. Te pectoral fn with 6 branching rays has a smooth spine. Te front and posterior borders of the pectoral fn spine are smooth, and it is longer than the dorsal fn spine. Te anal fn has 10 rays, while the pelvic fn has 5. Te upper lobe of the deeply forked caudal fn is longer than the lower lobe [8]. Te Singhiya River's slow-moving water (0.091 ± 0.112 m/s) with a bottom substrate primarily made of sand and mud (Figure 4) is where the current species was discovered. However, Amblyceps is thought to live in swiftly moving rivers and streams. Occasionally, between the months of June and November, there were fewer A. waikhomi individuals recorded. Te species was discovered in the river with the following environmental conditions: water velocity 0.091 ± 0.112 m/s, pH 6.4 ± 0.24, air temperature 32 ± 0.98°C, water temperature 29 ± 0.78°C, total hardness 99 ± 0.234 mg/l, DO 6.34 ± 0.56 mg/l, and free CO2 3.12 ± 012 mg/l. According to the local fsherman, Amblyceps is known to exist in Nepal's eastern Terai region but is primarily endangered by the removal of boulders, cobbles, pebbles, and gravel. Major risks to the current fsh species include ongoing road construction, microhydropower generation, the use of harmful herbicides, illegal electrofshing, deforestation, and water diversion [9]; furthermore, the existing fsh species of Nepal's hillside rivers and streams are determined to be seriously threatened by riparian loss, dams, aquatic habitat loss, and fragmentation, among other factors [10].

Data Availability
Te data used to support the fndings of this study are available from the corresponding author upon request.

Conflicts of Interest
Te authors declare that they have no conficts of interest.