Panaqolus albivermis, Lujan, Nathan K., Steele, Sarah & Velasquez, Miquel, 2013

Lujan, Nathan K., Steele, Sarah & Velasquez, Miquel, 2013, A new distinctively banded species of Panaqolus (Siluriformes: Loricariidae) from the western Amazon Basin in Peru, Zootaxa 3691 (1), pp. 192-198 : 193-197

Panaqolus albivermis , new species

Figure 1 . Table 1.

Holotype. MUSM 35879, 95.8 mm SL, Peru, Padre Abad Province, Irazola District, San Alejandro River, Ucayali River drainage, 195 masl, 8°55'02''N, 75°12'26''W, M. Velasquez, 13 June 2009.

Paratypes. Three specimens, collected with holotype. ANSP 182815, 1: 78.7 mm SL; AUM 58781, 1: 70.9 mm SL; ROM 93945, 1: 45.5 mm SL.

Diagnosis. Panaqolus albivermis can be diagnosed from all other Panaqolus except P. maccus by having head, body, and fins with widely separated small white to yellow spots, vermiculations, and/or thin oblique bands on a black base (vs. exclusively small white to yellow spots on a black base in P. albomaculatus , generally broad oblique bands of alternating light to dark brown in P. changae , P. gnomus , P. purusiensis , and a uniformly dark gray to black body color in P. d e n t e x, P. k o k o, and P. nocturnus ); P. albivermis can be diagnosed from P. maccus by having a black base color (vs. brown), by having parallel dentary tooth rows (vs. acute intermandibular tooth row angle), and by having a larger known adult body size (95.8 mm SL vs. 84.8; Schaefer & Stewart, 1993).

Description. Morphometrics in Table 1. Largest specimen 95.8 mm SL. Body depth increasing from tip of snout to greatest body depth at origin of dorsal fin, decreasing to posterior margin of adipose fin with slight increase at base of caudal fin. Dorsal profile slightly convex between snout and dorsal-fin origin. Ventral profile flat from snout to anus, slightly concave between anus and caudal fin. Ossified dermal plates with small odontodes covering snout and body flanks. Abdomen naked, lacking plates except for area between opercular openings. Cheek plates bearing hypertrophied, distally-hooked odontodes (mean 21, range 15-38, holotype 38) evertible to approximately 90o from sagittal plane in dorsal view; longest odontodes extending to posterior exposed margin of opercle. Orbit positioned dorsolaterally on head with opening sloped ventrolaterally at approximately 45o from sagittal plane in anterior view. Snout rounded. Slight ridge from anterolateral corner of naris to dorsal margin of orbit.

Oral disk occupying majority of ventral surface of head anterior of cleithrum. Premaxillary teeth 4-5 on left ramus (holotype = 5); dentary teeth 4-6 on left ramus (holotype = 4). All teeth with thick, strong shafts, and spoonshaped, paired cusps bent inward slightly; teeth slightly larger on dentary, teeth in middle of each row slightly larger than marginal teeth. Maxillary barbel short and attached to lower lip along most of length; ventral surface of labial disk with hemispherical papillae decreasing in size distally.

Holotype Paratypes

ILM Measurement MUSM 35879 ANSP 182815 AUM 58781 ROM 93945

1–20 Standard length 95.8 78.7 69.9 45.5 % of SL:

1–10 Predorsal length 45.2 42.8 46.2 44.0

1–7 Head length 36.1 35.3 37.9 36.4

7–10 Head-dorsal length 9.0 8.6 8.9 8.1

8–9 Cleithral width 30.8 32.4 31.4 29.7

1–12 Head-pectoral length 23.1 24.1 25.2 23.7

12–13 Thorax length 21.5 27.3 23.9 25.5

12–29 Pectoral-spine length 35.2 33.9 32.1 33.4

13–14 Abdominal length 24.3 24.9 23.4 21.6

13–30 Pelvic-spine length 30.7 30.7 26.8 30.4

13-13' Pelvic girdle width 19.9 20.5 18.5 21.0

14–15 Postanal length 30.9 31.9 29.0 30.1

14–31 Anal-fin spine length 13.8 14.2 14.9 11.0

10–12 Dorsal-pectoral depth 29.5 28.5 30.9 30.0

10–11 Dorsal spine length 33.0 34.3 33.6 36.0

10–13 Dorsal-pelvic depth 23.6 22.0 22.3 20.4

10–16 Dorsal-fin base length 28.3 28.3 26.9 24.5

16–17 Dorsal-adipose distance 14.7 13.9 14.1 11.8

17–18 Adipose-spine length 11.3 12.0 10.9 11.4

17–19 Adipose-upper caudal distance 17.6 11.6 17.4 18.9

17-18' Adipose height 10.7 9.7 11.2 9.9

15–19 Caudal peduncle depth 14.9 13.3 14.4 12.2

20-32 Caudal peduncle-middle caudal ray 16.4 12.0 16.0 17.5

20-33 Caudal peduncle-dorsal caudal spine 31.4 33.7 28.4 20.4

15–17 Adipose-lower caudal depth 22.8 25.2 23.1 22.6

14–17 Adipose-anal depth 17.3 16.4 17.9 15.8

14–16 Dorsal-anal depth 16.6 15.7 17.2 12.9

13–16 Pelvic-dorsal depth 27.7 25.0 28.4 24.4 % of HL:

5–7 Head-eye length 29.3 34.1 32.1 53.3

4–5 Orbit diameter 17.1 18.1 17.6 20.5

1–4 Snout length 66.1 62.1 60.3 59.0

2–3 Internares width 13.5 13.8 13.8 15.8

5–6 Interorbital width 40.8 39.4 38.7 41.0

7–12 Head depth 68.3 70.4 63.3 68.3

1–24 Mouth length 47.5 45.6 40.5 44.2

21–22 Mouth width 40.5 36.0 40.7 37.7

22–23 Barbel length 9.6 10.1 11.7 8.1

25–26 Dentary tooth cup length 18.9 16.6 10.5 *

27–28 Premaxillary tooth cup length 11.9 11.4 9.4 * Dorsal fin II,7(3)*, I,8(1); dorsal-fin spinelet small, V -shaped; (dorsal-fin lock present and functional); posteriormost dorsal-fin ray free from body. Pectoral fin I,5(2)*, I,6(2); adpressed pectoral-fin spine reaching approximately to anus, spine having hypertrophied odontodes increasing in length distally. Pelvic fin I,5; pelvic-fin spine extending to or past insertion of anal fin when adpressed. Anal fin I,4; second unbranched ray longest. Adipose-fin spine slightly curved distally, adnate to caudal peduncle via fleshy membrane with concave or convex posterior margin. Caudal fin I,14,I; caudal fin asymmetrically emarginate with ventral lobe longer than dorsal lobe.

Body broadest at cleithrum; posterior margin of exposed posterior process of cleithrum tapering to a point. Lateral median plates 24 or 25*, middorsal plates 23 or 24*, midventral plates 22–25*; anteriormost midventral plates strongly bent forming slight lateral ridge between verticals through pectoral- and dorsal-fin origins. Caudal peduncle plate rows five. One azygous preadipose plate; two predorsal plate rows not including nuchal plate; five interdorsal plate rows.

Color. Head, body, and fins with widely separated small white to yellow spots, vermiculations, and/or thin oblique bands on a black base. Several specimens have only thin widely-spaced, white to yellow oblique bands and lack spots entirely. Numbers of bands increase, and width of bands decrease, with body size, with juveniles having relatively few broad bands and adults having more numerous, thin bands and bands that are broken into vermiculations or spots.

Distribution and habitat. Known only from the San Alejandro River, a tributary of Aguaytia River in the upper Ucayali watershed in central Peru.

Etymology. The specific epithet albivermis is a combination of the Latin albus, meaning white, and vermis, meaning worm, and is in reference to this species’ variable but distinctive white to yellow markings.

Figures

FIGURE 1. Holotype of Panaqolus albivermis n. sp., 95.8 mm SL, Peru, Padre Abad Province, Irazola District, San Alejandro River, Ucayali River drainage, 195 masl, 8 ° 55 ' 02 '' N, 75 ° 12 ' 26 '' W, M. Velasquez, 13 June 2009 (photo by NKL).