Lasiancistrus saetiger, Armbruster, 2005

Armbruster, Jonathan W., 2005, The loricariid catfish genus Lasiancistrus (Siluriformes) with descriptions of two new species, Neotropical Ichthyology 3 (4), pp. 549-569 : 559-561

publication ID 10.1590/S1679-62252005000400013

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scientific name

Lasiancistrus saetiger

new species

Lasiancistrus saetiger , new species

Fig. 7 View Fig

Holotype. MCP 37942 View Materials , 100.1 mm SL, BRAZIL, Pará , rio Guamá near Ourém, 1°34’07"S, 47°10’08"W (purchased from an aquarium dealer and the coordinates are for his house on the edge of the river). GoogleMaps

Paratypes. MCP 22017 View Materials , 2 View Materials , 81.2 View Materials -85.0 mm SL, andAUM 42757, 1, 77.2 mm SL, same data as holotype GoogleMaps .

Diagnosis. Lasiancistrus saetiger can be separated from L heteracanthus and L. guacharote by having no plates on the abdomen, from L. schomburgkii by having large white spots on the head (vs. small white spots), by having the plates of the body outlined in black (vs. entire body uniformly dark), and by having no spots in the dorsal and caudal fins (vs. usually with small white spots), and from L. tentaculatus by having whiskers on the snout of nuptial males (vs. tentacules longer than their associated odontodes), and from L. caucanus and L. tentaculatus by lacking dark spots in the dorsal and caudal fins (vs. with dark spots).

Description. Morphometrics in Table 2. Largest specimen 100.1 mm SL. Body strongly dorsoventrally compressed and moderately wide. Head and nape gently sloped to insertion of dorsal fin. Dorsal profile very slightly sloped ventrally to dorsal procurrent caudal-fin spines, then rising slightly to caudal fin. Ventral profile flat to caudal fin. Supraorbital ridge almost absent with interorbital space slightly concave, almost flat. Supraorbital ridge continues as slightly higher, rounded ridge from anterior of orbit to slightly anteroventral of anterior nare. Mesethmoid raised slightly above lateral surface of snout to form slight ridge. Head contours smooth. Eyes small to medium.

Keels absent. All plates slightly convex medially to produce cylindrical body. Mid-dorsal and mid-ventral plate rows incomplete, generally ending below adipose fin; three rows of plates on caudal peduncle. Abdomen naked. First anal-fin pterygiophore not exposed to form platelike structure. 24 plates in median series.

Frontals, infraorbitals, nasals, opercles, pterotics, sphenotics, and supraoccipital supporting odontodes. Opercular odontodes occasionally moderately hypertrophied, thick, and sharp; whiskerlike odontodes rarely present on opercle. Whiskerlike odontodes present in evertible cheek mass and occasionally at anterolateral corner of snout; 7-15 whiskerlike odontodes in evertible cheek mass (N = 4); 30-39 (N = 4) total hypertrophied odontodes in cheek mass. Cheek plates evertible to approximately 90° from head, hypertrophied cheek odontodes folded under opercle when relaxed. Odontodes on tip of pectoral-fin spine slightly hypertrophied. Odontodes on lateral plates not enlarged to form keels.

Dorsal fin not reaching preadipose plate when adpressed; dorsal-fin spine not elongate, edge of dorsal fin straight. Dorsal-fin spinelet V-shaped, dorsal-fin spine lock functional. Dorsal fin II,7. Adipose fin with one preadipose plate and moderately long spine. Caudal fin slightly emarginate to forked, lower lobe longer than upper, i,14,i, with four dorsal procurrent caudal-fin rays and four ventral procurrent cau- dal-fin rays. Anal fin short with unbranched ray weak and usually about three quarters length of first branched ray. Anal fin i,5, Pectoral-fin spine reaching slightly posterior to insertion of pelvic fin when adpressed ventral to pelvic fin. Pectoral fin I,6. Pelvic fin reaching to posterior of anal-fin when adpressed. Pelvic fin i,5.

Dorsal flap of iris present. Flap between anterior and posterior nares short. Lips wide, fairly thin. Upper lip with small, round papillae. Lower lip with medium-sized papillae anteriorly and smaller ones posteriorly. Maxillary barbels very short, not reaching behind lower lip, occasionally completely adnate. Buccal papilla small. Jaws moderately wide, dentaries forming very oblique angle; premaxillaries forming a very shallow arc with an overall angle just slightly less than 180°. Teeth with fairly long, narrow cusps; lateral cusp approximately halflength of medial cusp, stalks of teeth long; 52-73 dentary teeth (N = 4) and 61-67 premaxillary teeth (N = 4).

Color. Body gray-brown with lighter spots. Medium-sized light spots on tip of snout, becoming very large posteriorly on head. Plates of nape and anterior body light gray-brown with dark edging giving appearance of large, light spots. Posteriorly on body, dark edges of plates most intense on anterior and posterior margins of plates forming oblique bars. Median fins without spots. Lower lobe of caudal darker than upper. Paired fins with medium-sized, round, light spots centered on rays. Pectoral-fin spines without spots; pelvic-fin spines with spots posteriorly, often faded. Abdomen slightly lighter than sides, with small, light spots laterally between posterior pectoral-fin insertion and insertion of pelvic-fin spine. Lower lobe of caudal fin darker than upper lobe.

Sexual dimorphism. No sexual dimorphism observed; specimens might not be mature.

Range. Lasiancistrus saetiger is known from a single collection of fishes from the rio Guamá, a tributary of the rio Capim, a drainage that enters the Atlantic just southeast of the mouth of the Amazon ( Fig. 3 View Fig ).

Etymology. From the Latin saetiger meaning bristle bearing, in reference to the presence of whiskerlike odontodes in Lasiancistrus .


Pontificia Universidade Catolica do Rio Grande do Sul