Peckoltia furcata ( Fowler 1940 )

Armbruster, Jonathan W., 2008, The genus Peckoltia with the description of two new species and a reanalysis of the phylogeny of the genera of the Hypostominae (Siluriformes: Loricariidae), Zootaxa 1822 (1), pp. 1-76 : 26-29

Peckoltia furcata ( Fowler 1940)

( Figs. 14–15 )

Chaetostomus furcatus Fowler, 1940: 238 , figs. 28–29. Type locality: Ucayali River basin, Contamana , Peru. Holotype: ANSP 68655 .

Material Examined: ECUADOR, Pastaza, Río Napo - Río Amazonas drainage: FMNH 70863 , 4 , 1 cs, 75.9– 87.4, Cusuimi, on Rio Cusuimi, about 150 km SE of Puyo, 02°39’S, 077°43’W, col. by B. Malkin, 18–23 July 1971. PERU, Amazonas, Río Amazonas drainage: ANSP 68655 , Holotype, 1, 90.7, Ucayali River basin, Contamana, W.C. Morrow, July-August 1937; MUSM 19052 , 3 , 122.8 – 153.5 , Río Santiago ce.nn. Soledad, Río Marañon basin, 03°31’28”S, 77°46’20”W, col. by M. Hidalgo, 20 September 2001; FMNH 97023 , 1 , 105.9 and LACM 39864–10 , 2 , 1 cs, 92.7–98.9, Rio Santiago , vicinity of Galilea, 1.5 km upstream of La Poza, Río Marañon basin, col. by Natives, 26–28 January 1980. PERU, Loreto, Río Amazonas drainage: SIUC 36691 , 1 , 139.4 , Río Itaya , 10 km S of Santa Clara, ornamental fishermen, 25 July 1995.

Diagnosis. Peckoltia furcata is unique among Peckoltia and perhaps hypostomines by having a strongly forked caudal fin with the upper lobe longer than the lower ( Fig. 15 ; vs. lower lobe longer); however, the condition of the caudal fin of most Peckoltia is poor with the tails either breaking in transit or eaten off by other fishes, making the utility of this character limited. Peckoltia furcata can be identified from all other Peckoltia except P. bachi , P. brevis , P. caenosa , P. lineola , and P. oligospila by having spots on the head; from P. bachi by having the spots on the head small (vs. large), the pelvic spines narrow (vs. wide), and the eye high on the head (vs. low); from P. brevis , P. caenosa , P. lineola , and P. oligospila by lacking spots on the abdomen at all ages (vs. present in large juveniles and adults); from P. brevis and P. lineola by having spots on the dorsal fin (vs. bands); from P.caenosa and P.lineola by having none of the spots on the head combining to form vermiculations; from P. caenosa by having dark spots in the dorsal fin (vs. light spots), and by having the dark and light bands on the caudal fin of about equal width (vs. light bands about 25% of width of dark bands); and from P. oligospila by having bands in the caudal fin (vs. spots).

Description. Morphometrics in Table 3, counts based on 12 individuals unless otherwise stated. Largest specimen examined 153.5 mm SL. Body fairly narrow and elongate. Head gently sloped to parieto-supraoccipital. Parieto-supraoccipital with tall crest. Parieto-supraoccipital crest raised well above nuchal region. Nuchal region rises slightly to nuchal plate. Dorsal profile sloped ventrally to dorsal procurrent caudal-fin spines, then rising rapidly to caudal fin. Ventral profile flat to ventral procurrent caudal-fin spines and then sloping ventrally to caudal fin. Supraorbital ridge rounded, contiguous, but slightly offset medially from rounded ridge proceeding from anterior margin of orbit to anterolateral corner of anterior nare. Head contours smooth except parieto-supraoccipital crest. Eye medium-sized.

Keels absent. Mid-ventral plates bent at their midline above pectoral fin to form ridge. Dorsal plates bent dorsally below dorsal fin to form ridges that converge at preadipose plate, dorsal surface flat between ridges. Five rows of plates on caudal peduncle. Abdomen completely covered in small plates except for small areas at bases of pectoral and pelvic fins and occasionally on throat. 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. 23–28 (mode 26) plates in the median series.

Frontal, infraorbitals, nasal, compound pterotic, sphenotic, and parieto-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 20–77, longest almost reaching first mid-ventral plate in adults. Cheek plates evertible to approximately 90° from head. Odontodes on tip of pectoral-fin spine slightly hypertrophied.

Dorsal fin short, not reaching preadipose plate fin when adpressed; dorsal-fin spine same length as proceeding rays making edge straight. Dorsal-fin spinelet V -shaped, dorsal-fin spine lock functional. Dorsal fin II,7. Adipose fin with one preadipose plate and fairly long spine. Caudal fin forked, lower lobe longer than upper, I,14,I with four to five (mode four) dorsal procurrent caudal-fin rays and four to five (mode four) ventral procurrent-fin rays. Anal fin short with unbranched ray weak and about same length of first branched ray. Anal fin I,4, Pectoral-fin spine reaching beyond pelvic fin when adpressed ventral to pelvic fin. Pectoral fin I,6. Pelvic fin reaching to posterior insertion of anal-fin or further when adpressed. Pelvic fin I,5.

Iris operculum present. Flap between anterior and posterior nares short. Lips wide, fairly thin. Upper lip with small, round papillae. Lower lip with small papillae anteriorly and posteriorly, becoming larger medially. Maxillary barbel short, maximally reaching base of evertible cheek plates. Buccal papilla small. Jaws narrow, dentaries forming angle slightly greater than 90°, premaxillaries forming gentle arc greater than 135°. Teeth with small, moderately wide cusps, lateral cusp approximately half length of medial cusp, stalk of tooth long; 26–42 dentary teeth (mode 37), 28–58 premaxillary teeth (mode 30).

Color: Base tan with brown markings. Head with small spots anteriorly, becoming slightly larger posteriorly and fading between head and dorsal fin or continuing to get larger and fading anywhere before caudal fin. Body with four dorsal saddles (occasionally faint), the first below the middle rays of the dorsal fin, the second below the posterior rays of the dorsal fin and slightly posterior, the third below the adipose fin and slightly anterior, and the fourth at the end of the caudal peduncle. The first two saddles combine midbody. All fins with large spots, spots combining in all except dorsal fin to form bands (although the distal row will occasionally fuse in the dorsal fin). The light interspaces in all fins except the caudal are about half the width of the dark spots or bands. The light interspaces of the caudal fin about same width as dark bands. Dark spot between dorsal-fin spinelet and spine. Abdomen and ventral surface of caudal peduncle lighter than sides. Juveniles colored as adults, but spots significantly larger and fewer bands or spots in the fins.

Sexual Dimorphism: Nuptial males with hypertrophied odontodes on sides and posterior part of head; hypertrophied odontodes becoming larger posteriorly. Hypertrophied odontodes on upper caudal-fin spine and adipose spine. Upper caudal-fin spine not thickened. Odontodes on pectoral-fin spine noticeably larger.

Range: Known from the upper Río Amazon, Río Marañon, and Río Ucayali of Ecuador and Peru ( Fig. 5 ).

Comments: The placement of Peckoltia furcata is far from assured. The dentary angle never gets quite to 90°, and it appears intermediate in angle between Hemiancistrus sabaji and Peckoltia . In most conditions such as color and body shape, P. furcata seems intermediate between H. sabaji and the rest of Peckoltia , but given that the jaw angle is smaller in P. furcata than anything I have identified as Hemiancistrus , I consider it a Peckoltia . Certainly the phylogeny of Peckoltia must be better explored to determine the relationships of the species.

Figures

FIGURE 5. Distribution of Peckoltia bachi (circles) and P. oligospila (diamonds). Open symbols are type localities. Symbols may represent more than one locality.

FIGURE 14. Lateral view of holotype of Chaetostomus furcatus, ANSP 68655, 90.7 mm SL. Photograph by K. Luckenbill.

FIGURE 15. Dorsal, lateral, and ventral views of Peckoltia furcata, SIUC 36691, 139.4 mm SL. Inset is of extended caudal fin to show that the dorsal caudal-fin spine is longer than the ventral. Photographs by J.W. Armbruster.