Pterygoplichthys weberi, Armbruster & Page, 2006

Armbruster, Jonathan W. & Page, Lawrence M., 2006, Redescription of Pterygoplichthys punctatus and description of a new species of Pterygoplichthys (Siluriformes: Loricariidae), Neotropical Ichthyology 4 (4), pp. 401-409 : 406-408

Pterygoplichthys weberi , new species

Fig. 5

Holotype. ICNMHN 13455, holotype, 191.4 mm SL, Colombia, Caquetá, Florencia, Río Caqueta drainage, Laguna El Vaticano, August 2004, no collector.

Paratypes. FMNH 96959 , 3 alc., 1 cs. 166.5-196.0 mm SL, Ecuador, Napo, quebrada to Río Tiputini, ( Río Napo drainage), D. Stewart, M. Ibarra, and R. Barriga , 29 October 1981 . MSU 2736.2 , 1, 196.9 mm SL. Ecuador (no precise locality given) . FMNH 101378 , 1, 110.5 mm SL, Colombia, Amazonas, Amazon River at 2 to 3 miles upstream from Leticia, Navarro , Thomerson , et al., 13 November 1973 . USNM 177204 , 1, 172.8 mm SL, Ecuador, Chichinota, on left bank of Bobonaza River , 2°22’S, 76°38’W , R. Olalla , January 1949 .

Non-types. CAS 56746, 2 , 86.6 -137.0 mm SL and USNM 86761, 101.7 - 102.8 mm SL, Peru, Loreto, Yurimaguas creeks, W . R. Allen, November 1920 .

Diagnosis. Pterygoplichthys weberi can be separated from all other Pterygoplichthys except P. punctatus by having the buccal papilla at least shallowly divided medially; and from all other Pterygoplichthys by having the lateral keel odontodes almost perpendicular to the plates (vs. sloped posteriorly) and by having the longest keel odontodes longer than the plates in the lateral-line row in the adult. Pterygoplichthys weberi can be further separated from P. punctatus by having the buccal papilla partially divided in the adult (vs. fully divided at all ages; Fig. 1 ), by having few spots on the abdomen and the bases of the fins (vs. many spots), and by having a wider body (SL/cleithral width 3.3-3.4 vs. 3.6-4.0).

Pterygoplichthys weberi can be further separated from P. scrophus , P. gibbiceps , P. joselimaianus , P. xinguensis , P. lituratus , and P. parnaibae by lacking an elevated supraoc- cipital (vs. having an elevated supraoccipital forming an obvious crest); from P. etentaculatus by having fewer than five hypertrophied odontodes on the cheek plates (vs. more than five); from P. joselimaianus by having dark spots (vs. light spots); from P. undecimalis and P. zuliaensis by having a broadly round snout (vs. a narrow pointed snout, Fig. 3 ); from P. multiradiatus by usually having 11 dorsal-fin rays (occasionally 12 vs. 12-13 fide Weber, 1992); and from P. anisitsi , P. disjunctivus , P. multiradiatus , and P. pardalis by having hypertrophied odontodes on the cheek plates of the adult (vs. hypertrophied cheek odontodes absent).

Description. Member of Hypostominae : Pterygoplichthyini : Pterygoplichthys as diagnosed by Armbruster (2004). Morphometric data given in Table 1 . Largest specimen 196.9 mm SL. Head forming arch from tip of snout to anterior margin of supraoccipital. Supraoccipital and nuchal region forming hump. Body depth decreases from origin of dorsal fin to dorsal procurrent caudal spines, and then increases to caudal fin. Ridge from anterodorsal corner of orbit runs ventral to nares, ending slightly anteroventral of anterior nare. Crest continuing posteriorly from supraorbital ridge with portion on sphenotic and pterotic bent strongly dorsally, posterior portion on pterotic angled dorsally, continuous with keel of mid-dorsal plate series. Dorsal rim of orbit slightly higher than interorbital space.

Keels on lateral plates prominent, formed of ridges of bone and hypertrophied, thick, very sharp odontodes. Keels present on all plate rows. One or two plates forming short, accessory row between dorsal and mid-dorsal plate series near head; keel on accessory plate row contiguous with but widely separated from keel on dorsal plate series beginning posteriorly to origin of dorsal fin. Keel on anterior plates of dorsal series beginning at midline just anteriorly to posterior margin of supraoccipital, angled to lateral edge of nuchal plate. Ridge on pterotic contiguous with keel on anterior three plates of mid-dorsal plate series; keel on remaining plates of middorsal plate series ventral to that of keel on anterior three plates.

Nares separated by short flap of skin held erect in life. Dorsal, mid-dorsal, median and mid-ventral plate rows complete from head to caudal fin. Ventral plate row begins posteriorly to insertion of pelvic fin and continues to caudal fin. Base of caudal fin covered in elongate, roughly triangular plates. Ventral surface of body (except region dorsal to pectoral fin and ventral to mid-ventral plate row) covered in small plates. Plates on abdomen increase in number with standard length. Head covered in small plates. Frontal, nasal, sphenotic, infraorbitals, opercle, pterotic-supracleithrum, suprapreopercle, and supraoccipital supporting odontodes. Platelets covering anteroventral corner of opercle separated from opercle; platelets may be everted to approximately 90° from head. Evertible cheek plates with zero to four slightly hypertrophied odontodes (largest extending approximately to posterior end of opercle).

Dorsal fin long and low in adult, higher in juvenile, consisting of small, V-shaped spinelet, fairly strong spine, and 11-12 rays; adpressed dorsal fin does not reach adipose fin. Caudal fin forked, lower lobe longer than upper. Pectoral-fin spine strong, reaches posteriorly to pelvic-fin rays when depressed ventral to pelvic fin; cleithrum with exposed process dorsal to pectoral-fin rays and strongly angled dorsally; pectoral fin inserted on same plane as pelvic fin such that spine, when depressed parallel with body, lies on top of and in contact with pelvic fin. Pelvic-fin spine thin, flexible, reaches barely to base of anal fin.Anal fin with relatively strong, unbranched first ray supporting odontodes. Adipose fin consisting of median unpaired preadipose plate and strong, pointed spine; adipose-fin membrane not reaching procurrent caudal-fin spines. Pectoral fin I,6, pelvic fin I,5, anal fin I,4, caudal fin I,14,I. Jaws weakly angled, dentaries forming angle of approximately 90º. Teeth bicuspid, median cusp short, lateral cusp about half length of median cusp, stalk moderately long; 26-31 dentary teeth, 23-30 premaxillary teeth. Median plates 27-28 (mode 28), adipose-caudal plates three to five (mode four), anal-caudal plates 11-12 (mode 12), dorsal-adipose plates six to seven (mode seven). Buccal papilla lobulate and divided medially in juvenile, but only slightly bifurcated in adult ( Fig. 1b ).

Color in alcohol. Body and fins brown and covered with medium to large black spots. Spots smallest on snout, progressively larger posteriorly, sometimes fading on caudal peduncle. Venter covered with discrete (uncoalesced) spots; spots smallest on throat and becoming progressively larger to interpelvic area. Spots proportionally larger on juvenile. Caudal peduncle lighter ventrally than dorsally. Four faint dorsal saddles; first under anterior rays of dorsal fin, second under last few rays of dorsal fin and slightly posteriorly, third under adipose fin and anteriorly to fin, and fourth at base of caudal peduncle.

Range. Known from the Río Marañon, Río Ucayali, Río Caquetá, and upper Río Amazonas drainages of Colombia, Ecuador, and Peru ( Fig. 4 ).

Etymology. Named for Claude Weber of the Muséum d’histoire naturelle, Geneva, for his fine work on Pterygoplichthys and his contributions to loricariid systematics.

Figures

Fig. 5. Dorsal, lateral, and ventral views of Pterygoplichthys weberi, ICNMHN 13455, holotype, 191.4 mm SL. Photos by J.W. Armbruster and M. Arce.

Fig. 1. Mouth and buccal papilla (indicated by arrow) of a. Pterygoplichthys punctatus, MCP 35755, 203.1 mm SL, b. P. weberi, FMNH 96959, holotype, 183.9 mm SL, c. P. multiradiatus, AUM 18947, 153.3 mm SL. Photos by J.W. Armbruster and L.M. Page.

Fig. 3. Dorsal profiles of snouts of a. Pterygoplichthys punctatus, UF 148742, 160.1 mm SL and b. P. zuliaensis,AUM 22586, 222.0mmSL.

Fig. 4. Localities for Pterygoplichthys punctatus (squares) and P. weberi (dots). Open symbols are type localities. Localities for P. punctatus from Weber (1992) and specimens examined in this study. Because the rio Urubu locality of P. punctatus did not have precise locality information, the locality is indicated at random in the lower Urubu. Base map by M. J. Weitzman.