identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
930AD924FFF2FFEFBC82FF37FEC0D3FF.text	930AD924FFF2FFEFBC82FF37FEC0D3FF.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Mystus oculatus (Valenciennes 1840)	<div><p>Mystus oculatus (Valenciennes, 1840)</p><p>(Fig. 1 &amp; 2)</p><p>Chresonymy. Bagrus oculatus Valenciennes in Cuvier &amp; Valenciennes 1840:424 (type locality: Malabar coast, India). Macrones armatus —Day, 1865: 289 (type locality: rivers and occasionally in backwaters, Cochin, India)</p><p>Macrones oculatus — Day (1878: 448)</p><p>Material examined. ZSI/ NRC F-10759 (6), 62.9–72.9 mm SL; India: Kunthi River, Malappuram District, Kerala .</p><p>Photographs examined. Mystus oculatus, Holotype, MNHN 0000-1195, Malabar coast, India; M. armatus, syntypes, BMNH 1865.7.17.21, BMNH 1975.9.30.13 (dry), NMW 45165, rivers and occasionally in backwaters, Cochin, India; M. armatus, non-type, AMS B.7573, Canara, India.</p><p>Diagnosis. Mystus oculatus can be readily distinguished from all congeners known from peninsular India in having a live colour pattern consisting of a prominent black blotch at the base of dorsal-fin spine, diffuse humeral blotch, and dark, sub-triangular midpeduncular blotch (Figs. 1 &amp; 2). Mystus oculatus can be further distinguished from Mystus bleekeri, M. irulu and M. seengtee in having adipose-fin base not reaching base of last dorsal-fin ray anteriorly (vs. reaching), cranial fontanel almost reaching (vs. reaching) base of supraoccipital process, and fewer vertebrae (34 vs. 38–41); from M. vittatus in having serrated (vs. smooth) posterior margin of dorsal-fin spine, cranial fontanel almost reaching base of supraoccipital process (vs. extending just beyond level of posterior orbit margin) (Fig. 3), and shorter adipose-fin base (15.2–16.8 % SL vs. 19.0–21.2); from M. gulio in having longer adipose-fin base (15.2–16.8 % SL vs. 8.0–10.1), lesser dorsal to adipose distance (17.3–23.4 % SL vs. 24.4–29.6), and cranial fontanel almost reaching base of supraoccipital process (vs. extending just beyond level of posterior orbit margin); and from M. malabaricus and M. montanus in lacking (vs. having) prominent mid-lateral stripe, having (vs. lacking) pale longitudinal stripes above and below the lateral line, greater post-adipose distance (15.9–20.0 % SL vs. 10.4–14.4), and shorter adipose-fin base (15.2–16.8 % SL vs. 19.8–28.7).</p><p>Description. Body elongated and laterally compressed. Head depressed, broader than deep, dorsal profile slightly convex, ascending to dorsal-fin origin, flat to adipose fin, sloping gently ventral to posterior extremity of adipose fin and rising gently to caudal-fin base. Ventral profile almost straight. Skin smooth, lateral line complete, midlateral in position. Snout rounded when viewed dorsally. Eyes large, ovoid, and positioned laterally near upper half of head. Bony element of dorsal surface of head covered with thin skin; bones readily visible, particularly on posterior half of neurocranium. Cranial fontanel extending from behind snout, almost reaching base of supraoccipital process. Supraoccipital process elongate, with gently converging sides and pointed tip; extending to anterior nuchal plate. Gill opening wide, extending from post temporal region to beyond isthmus. Gill membrane free from isthmus, first branchial arch with 21 (2) gill rakers.</p><p>Mouth subterminal, upper lip fleshy, projected anteriorly beyond lower jaw. Mouth subterminal; upper lip fleshy, projecting anteriorly beyond lower jaw. Oral teeth small, villiform. Premaxillary tooth band curved, slightly wider at distal ends. Dentary tooth band narrower than premaxillary tooth band, tapering laterally. Vomerine tooth band unpaired, continuous across midline; band width wider than premaxillary band at midline. Four pairs of barbels. one pair of short and slender nasal barbels extending beyond posterior orbital margin; one pair of long and slender maxillary barbels extending beyond base of anal fin. Two pairs of mandibular barbels. Outer mandibular barbels longer than inner; originating posteriolateral of inner mandibular barbel, extending to half of distance between base of last pectoral-fin ray and origin of pelvic fin. Inner mandibular barbels originating closer to midline and extending to level of last pectoral-fin ray.</p><p>Dorsal fin with strong spine and 7 rays (6); its origin at one-third of body length. Dorsal fin margin convex, with anterior branch of fin rays longer than other branches; spine moderately long, straight and slender, serrated along posterior margin of spine. Nuchal plate triangular and narrow. Pectoral fin with stout spine and 7 rays (6), pointed at tip. its anterior margin smooth, posterior margin with serrae along entire length. Adipose fin elongated, with deeply incised posterior portion, originating posterior to dorsal fin and extending towards caudal peduncle. Pelvic-fin origin at vertical through posterior end of dorsal-fin base, with i,5 branched rays (6) and slightly convex margin, tip of adpressed pelvic fin not reaching origin of anal fin. Anal fin base ventral to adipose-fin base, with ii, 9 (4) or 10 rays (2). Anus opening located at vertical through middle of adpressed pelvic fin, urogenital opening located at tip of adpressed fin. Caudal peduncle moderately deep. Caudal fin deeply forked, with i,7,7, i (6) principal rays; both lobes acutely pointed, upper lobe longer than lower. Procurrent rays extending anterior to caudal-fin base. Vertebrae 34 (2).</p><p>Colouration. In life (Fig. 2): dorsal surface of head bronze, fading to pale cream ventrally. Body predominantly light tan on dorsal and lateral surfaces, fading to pale cream or off-white ventrally. Two pale white stripes present above and below lateral line, extending posteriorly to caudal-fin origin: first stripe originating from supraoccipital area, second originating from below dorsal-fin origin. Black blotch, larger than eye size, at base of dorsal-fin spine, diffuse humeral blotch and sub-triangular midpeduncular blotch present. Dorsal, pectoral and pelvic fins with yellowish edges, fading to hyaline distally. Adipose, caudal and anal fins yellow, particularly noticeable on caudal fin. Barbels whitish and translucent.</p><p>Preserved specimens (Fig. 1) lose colours and body patterns, except the spot at base of dorsal-fin base. Body greyish brown, darker on dorsum, progressively lighter towards a whitish abdomen. Fins opaque, and tip of dorsal, adipose, anal and caudal fins black.</p><p>Distribution. Mystus oculatus is endemic to the Western Ghats region, where it occurs with certainty in the lower reaches of the west-flowing Bharathapuzha River in Kerala. There are reports of this species from other west-flowing rivers in Kerala such as the Periyar and Neyyar, that lie south of the Bharathapuzha (Ajithkumar et al. 2001 &amp; Abraham et al. 2011). While these records seem plausible, the history of misidentifications in Mystus necessitates the examination of voucher specimens to accurately define the distributional range of this species. Indra (1992) reported this species from the Valliyar River, a small east-flowing river in Kanyakumari District, southern Tamil Nadu. However, subsequent surveys in the region (e.g. Rajagopal &amp; Davidar, 2013) failed to record this species. Reports of this species from the east-flowing rivers in Tamil Nadu require further verification, and are likely to be misidentifications.</p></div>	https://treatment.plazi.org/id/930AD924FFF2FFEFBC82FF37FEC0D3FF	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		MagnoliaPress via Plazi	Vijayakrishnan, Balaji;Shinde, Gaurav Anil	Vijayakrishnan, Balaji, Shinde, Gaurav Anil (2026): Redescription of Mystus oculatus (Valenciennes, 1840), a senior synonym of Mystus armatus (Day, 1865) (Teleostei: Bagridae). Zootaxa 5839 (3): 470-482, DOI: 10.11646/zootaxa.5839.3.3, URL: https://doi.org/10.11646/zootaxa.5839.3.3
