Comprehensive Description

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Peckoltia braueri (Eigenmann 1912)

(Figs. 1-2)

Hemiancistrus braueri Eigenmann 1912 ZBK :232, Pl. 28 (figs. 1-2). ZMB 3174.

Material Examined: GUYANA , Rupununi (Region 9) , Takutu River - Negro River drainage: ANSP 180206, 12, 44.8-91.7 mm SL and AUM 36228, 20, 44.7-96.5, Takutu River ca. 2.75 km W Saint Ignatius, 03.35500°, -059.83077°, 5- 6 November 2002 , J.W. Armbruster, M.H. Sabaj, D.C. Werneke, C.L. Allison, M.R. Thomas, C.J. Chin, D. Arjoon, and L. Atkinson ; ANSP 180207, 2, 39.8-50.6 and AUM 35525, 3, 84.1-66.0, Pirara River, tributary of the Ireng River, 3.5 km NNW Pirara, 03.64870°, -059.68897°, 2 November 2002 , J.W. Armbruster, M.H. Sabaj, M.R. Thomas, D.C. Werneke, and D. Arjoon ; ANSP 180208, 1, 93.5 and AUM 38882, 2, 77.7-103.0, same locality as ANSP 180206, 1 November 2003 , J.W. Armbruster, M.H. Sabaj, M. Hardman, D. Arjoon, N.K. Lujan, and L.S. de Souza ; and AUM 37914, 1, not measured, Takutu River at Saint Ignatius, 1.86 km NNE Lethem, 03.35578°, -059.80518°, 2 November 2003 , J.W. Armbruster, M.H. Sabaj, M. Hardman, D. Arjoon, N.K. Lujan, and L.S. de Souza . BRAZIL , Roraima , Rio Negro drainage: MZUSP 33703, 1, 83.6 , and MZUSP 34652, 1, 62.0, Rio Branco, Bem Querer rapids, 8 January 1984 , M. Goulding ; MZUSP 34563, 5, 74.7-82.4. Igarapé do Cujobim, in front of Ilha de Maracá , 13 January 1984 , M. Goulding .

Diagnosis: Peckoltia braueri can be separated from all other described Peckoltia ZBK except P. cavatica ZBK by the presence of an orange band in the dorsal fin and by having thin, wavy, black lines that tend to outline the plates and bones of the head (Figs. 1-2). Peckoltia braueri can be separated from P. cavatica ZBK by having the dorsal saddles better developed (vs. barely visible), by having the head plates and bones not completely outlined in black and with lines intense (vs. having all of the head plates and bones completely outlined in black and with the lines lighter), by having black vermiculations on the pterotic-supracleithrum(vs. no vermiculations), by having at least one, broken band in the caudal fin (vs. no bands in the caudal fin), and by having the marginal orange band of the dorsal and caudal fins not as thick or as intense as in P. cavatica ZBK . The only other described species of Peckoltia ZBK similar to P. braueri in coloration is P. vermiculata , which can be separated by having vermiculations on the dorsal head bones and plates other than the pterotic (vs. coloration confined to the borders between bones and plates in P. braueri ).

Description. Member of Peckoltia ZBK as defined by Armbruster (2004). Morphometrics in Table 1. Medium-sized loricariids, largest specimen 103.0 mm SL. Body stout and fairly wide. Head and nape gently sloped to insertion of dorsal fin. Supraoccipital with slight rounded crest, slightly higher than nuchal region. Dorsal profile sloped ventrally to dorsal procurrent caudal-fin spines, then rising rapidly to caudal fin. Ventral profile flat to caudal fin. Supraorbital ridge rounded, continuing to anterolateral corner of anterior nare. Mesethmoid raised slightly above lateral surface of snout to form slight ridge. Head contours smooth. Eyes relatively large.

Keels absent. Inframedian plates bent at their midline above pectoral fin to form ridge. Dorsal plates bent dorsally below dorsal fin to form very slight ridges that converge at adipose fin, dorsal surface flat between ridges. Five rows of plates on caudal peduncle. Abdomen largely naked except region below pectoral girdle that is usually plated in adults, the region laterally between paired fins that is plated, and occasionally plates in anteromedial section of thorax and just anterior to anus. First anal-fin pterygiophore exposed to form a platelike structure. A pair of lateral plates converging at midline between anus and exposed first anal-fin pterygiophore. 24-26 (mode = 25) plates in the median series.

Frontals, infraorbitals, nasals, pterotic-supracleithra, sphenotics, and supraoccipital, supporting odontodes; opercle supporting odontodes in juveniles but not in adults, posterodorsal corner of opercle covered by one or two plates in adults. Odontodes on lateral plates not enlarged to form keels. Hypertrophied cheek odontodes 13-56, longest reaching first inframedian plate in adults. Cheek plates evertible to approximately 90° from head. Odontodes on tip of pectoral-fin spine slightly hypertrophied.

Dorsal fin 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 II7 (except for one individual with II6). Adipose fin with one preadipose plate and moderately long spine. Caudal fin emarginate, lower lobe longer than upper, I14I with four to five (mode four) dorsal procurrent caudal-fin rays and three to four (mode four) ventral caudal-fin rays. Anal fin short with unbranched ray weak and approximately same length of first branched ray. Anal fin I4. Pectoral-fin spine reaching slightly behind posterior insertion of pelvic fin when adpressed ventral to pelvic fin. Pectoral fin I6. Pelvic fin reaching to middle of anal-fin when adpressed. Pelvic fin I5.

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 short, not reaching gill opening. Buccal papilla represented only by a very small flap. Jaws narrow, dentaries forming angle just slightly greater than 90°, premaxillaries forming a very shallow arc with an overall angle just slightly less than 180°. Teeth with small, moderately narrow cusps, lateral cusp approximately half-length of medial cusp, stalks of teeth long, dentary and premaxillary teeth about equal in length; 13-29 dentary teeth (mode = 20) and 15-29 premaxillary teeth (mode = 20).

Color. Color same for live and preserved specimens except that live specimens have thin, orange bands at edge of dorsal and caudal fins. Background color gray-brown. Dorsal surface with four dark saddles, saddle one below second and third dorsal-fin rays, saddle two below last two dorsal-fin rays and slightly behind dorsal fin, saddle three below adipose fin, and saddle four at end of caudal peduncle. First two saddles combine at lateral line to form dark patch that extends from second saddle almost to pterotic-supracleithrum anteriorly and to ventral margin of inframedian plate row. Head plates and bones and plates of the nuchal region outlined in black with black lines also forming vermiculations on the larger head bones; outlining of plates and bones varying in degree of completeness, but never complete. Dorsal fin spine with large, oblong spots anteriorly, dorsal fin with slight distal orange band in life, and either entirely gray or with two wide, broken dark bands. Caudal-fin spines with oblong spots, caudal fin with one to two wide, broken bands and slightly orange edge to caudal fin in life. Ventral surface lighter than sides, saddle three contiguous with opposite side around ventral surface, but very light on ventral surface and saddle four contiguous with opposite side and dark around caudal peduncle. Pectoral fin mottled and pelvic fin with two wide, dark bands.

Juveniles colored similarly to adults, but dark colors more intense. There is an additional dark patch between saddles two and three in larger juveniles and saddles one and two are generally separate (Fig. 2). The pectoral fin generally has one to two bands. In the smallest individuals, saddles three and four connected ventrally making the body appear mottled.

Sexual dimorphism. Several individuals seem to be in the process of developing hypertrophied odontodes on the body as are found in most male Peckoltia ZBK during the breeding season.

Range. Collected from three localities around Lethem in the Takutu and Pirara Rivers (Fig. 3). Found in swift riffles among very large boulders. Also known from the mainstem Rio Branco near Caracarai and the Rio Uraricoera drainage of Brazil.

Comments. Despite the fact that the original specimens did not have a locality, Müller and Troschel (1849) state the locality as being in the Takutu, and Eigenmann (1912) fixes the type locality as being in the Takutu. The specimen was already devoid of color by Eigenmann’s time (see photo in Eigenmann, 1912) precluding any critical examination of color, which is the most important element in separating Peckoltia braueri from other species of Peckoltia ZBK .

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