Panaqolus, Isbrucker & Schraml, 2001

Cramer, Christian Andreas & Py-Daniel, Lúcia Helena Rapp, 2015, A new species of Panaqolus (Siluriformes: Loricariidae) from the rio Madeira basin with remarkable intraspecific color variation, Neotropical Ichthyology (Neotrop. Ichthyol.) 13 (3), pp. 461-470 : 468-469

Key to the Panaqolus species (modified from Cramer, 2014)

1 Head, body and fins without alternating dark and light bands ............................................................................. 2

1’ Head, body and/or fins (in P. nocturnus and adult P. purusiensis only on fins [at least anal and pelvic fins]) with alternating dark and light bands..............................5

2 Dentary tooth rows in an angle of nearly 70°, forming a V. Normally dentaries meet in the middle; body and fins not covered with small light dots .................................. 3

2’ Dentary tooth rows in a very acute angle (50° or less) or nearly parallel, often not meeting in the middle, forming a \ /; body and fins covered with small white or yellowish dots (if faded on body, traces are present at least on dorsal and caudal fins) ................................................. 4

3 Body uniformly grayish black; teeth quadrate with strong lateral cusp (upper Maroni River basin, French Guiana) ................................................................ P. koko

3’ Body dark with three lighter saddles between dorsal and caudal fins; teeth rounded without or with tiny lateral cusps ( upper Río Amazonas, Río Ucayali, Río Napo, and Río Marañón drainages)............................ P. dentex

4 Maxillary barbels elongate (9.7-19.6% HL), small eyes with orbital diameter 12.5-16.8% HL, white dots on nearly all plates (rio Madeira, rio Marmoré , Río Madre de Dios drainages).................................................. P. nix

4’ Maxillary barbels short (1.6-8.9% HL), orbital diameter 16-20% HL, white dots on less than half of the plates ( upper Río Amazonas, Río Ucayali, Río Napo, and Río Marañón rainages)............................... P. albomaculatus

5 Dark body with diffuse lighter markings; never showing bands or stripes on body or head, only on fins ( upper Río Amazonas, Río Ucayali, Río Napo, and Río Marañón drainages) .................................................... P. nocturnus

5’ Body with alternating light and dark bands, at least in individuals <90 mm SL................................................ 6

6 Bandsontrunkangledinananterodorsaltoposteroventral direction ( upper Río Amazonas, Río Ucayali, Río Napo and Río Marañón drainages).......................... P. gnomus

6’ Bands on trunk angled in a posterodorsal to anteroventral direction......................................................................... 7

7 Dark bands on trunk and dorsal fin as wide as or thinner than light interspaces; trunk with 6-12 (mode=8) dark bands; adipose with 1-2 (usually 2) dark bands (Río Nanay and Río Itaya drainages) .................... P. changae

7’ Dark bands on trunk and dorsal fin much wider than light interspaces in specimens larger than 25 mm SL (specimens larger than 85 mm SL may not show clear bands on the trunk); trunk with 3-9 dark bars .............. 8

8 Dentary tooth rows parallel; body base color black ( Río San Alejandro , Ucayali drainage) ............. P. albivermis

8’ Dentary tooth rows acutely angled; body base color brown or olivaceous ...................................................... 9

9 Small adult size (max. 87 mm SL, usually smaller); trunk with 3-7 (mode=4) dark bars; dorsal-pelvic depth 19-23% (mean=21%) of SL (Río Orinoco drainage) ....... P. maccus

9’ Large adult size (max. 130.4 mm SL); trunk with 5-9 (mode=7) dark bars in specimens larger than 25 mm SL (smaller specimens with 4 bars; specimens larger than 85 mm SL may not show clear bands on the trunk); dorsal-pelvic depth 22-32% (mean 27%) of SL (rio Purus drainage)................................................... P. purusiensis