Redescription of Pterygoplichthys punctatus and description of a new species of Pterygoplichthys ( Siluriformes : Loricariidae )

Pterygoplichthys punctatus and P. weberi, new species, are unique among hypostomines in having a medially divided buccal papilla. The two species can be separated from one another by color (small spots in P. punctatus, large in P. weberi), condition of the buccal papilla (deeply divided at all ages in P. punctatus vs. shallowly divided in adults of P. weberi), condition of the lateral keel odontodes (fairly short and directed posteriorly in P. punctatus vs. large and directed almost laterally in P. weberi), and body width (SL/cleithral width 3.6-4.0 in P. punctatus vs. 3.3-3.4 in P. weberi). Pterygoplichthys punctatus is known from the rio Madeira drainage and the rio Urubu of Brazil and has published, but unconfirmed localities in the rio Purus and rio Tocantins basin, and P. weberi is known from the Río Marañon, Río Ucayali, and upper Río Amazonas drainages of Colombia, Ecuador, and Peru.


Introduction
With about 80 genera and over 700 species, Loricariidae is the largest family of catfishes (Siluriformes).Loricariids are endemic to South America (absent in Chile), Panama, and Costa Rica and are characterized by having large bony plates and a ventral suctorial mouth with or without noticeable barbels.
A group of loricariid catfishes with 10 or more dorsal-fin rays is commonly referred to as sailfin catfishes.Weber (1991Weber ( , 1992) ) reviewed variation among sailfin catfishes and assigned them to three genera.Species with an elevated supraoccipital process were placed in Glyptoperichthys Weber, 1991, those lacking the elevated supraoccipital process and with the supraoccipital bone bordered posteriorly by one large plate were assigned to Pterygoplichthys Gill, 1858, and those lacking the elevated supraoccipital process and with the supraoccipital bone bordered posteriorly by three plates were assigned to Liposarcus Günther, 1864.Armbruster (2004) noted that the synapomorphies provided by Weber (1991Weber ( , 1992) ) were inadequate to diagnose three genera, and that neither Pterygoplichthys nor Glyptoperichthys could be recovered as monophyletic.He placed Liposarcus and Glyptoperichthys in the synonymy of Pterygoplichthys and recognized the tribe Pterygoplichthyini (originally misspelled as Pterygoplichthini) for Pterygoplichthys and an undescribed genus (the Hemiancistrus annectens group of Armbruster, 1998) from the trans-Andean region.Pterygoplichthyini was diagnosed by an increased number of plates between the opercle and the suprapreopercle (two or three vs. zero or one) and the presence of a large, respiratory stomach attached to the dorsal wall of the abdominal cavity via a sheet of connective tissue.Pterygoplichthys cannot be diagnosed by any unique synapomorphies; however, Armbruster (2004) listed several homoplasic synapomorphies: the presence of more than seven dorsal-fin rays, no or a diminutive interopercle that is on the hyomandibula when present, and a reduction in the number of vertebrae (eight to 11 vs. 12-20) between the dorsal fin and hypural.
Pterygoplichthys punctatus was based on a specimen from the rio Madeira drainage of Brazil (Günther, 1864).In his revision of sailfin catfishes, Weber (1992) considered the range of P. punctatus to include much of the upper Amazon, and he included photographs of the holotype and a specimen from the Río Ucayali of Peru that he considered to be P. punctatus; however, our examination of specimens reveals that those from the upper Amazon, including the Río Ucayali, differ from those in the rio Madeira in terms of color, shape, and the presence of large, sharp keel odontodes.In this paper, we describe the species in the upper Amazon as new, redescribe P. punctatus, and provide a revised key to the species of Pterygoplichthys.

Materials and Methods
Measurements were made with digital calipers to the nearest 0.1 mm.Names of plate rows follow Schaefer (1997).Measurements follow Weber (1992), which largely follow Boeseman (1968).Counts include lateral-line plates (plates in median plate row), adipose-caudal plates (plates in dorsal series from posterior edge of adipose-fin spine to caudal fin), anal-caudal plates (plates in ventral series from plate posterior to posterior insertion of anal fin to caudal fin), and dorsaladipose plates (plates in dorsal series from plate posterior to posterior insertion of dorsal fin to plate anterior to insertion of adipose-fin spine).Plate counts exclude the column of triangular plates beyond the hypural.Tooth counts were made on the left dentary and premaxillary bones and included all fully erect teeth.SL = standard length, HL = head length.Other specimens examined are listed in Page et al. (1996) and Armbruster (1998Armbruster ( , 2004)).Institutional abbreviations are as listed at http://www.asih.org/files/codons.pdf.(Weber, 1991) 5. Weakly developed hypertrophied odontodes on evertible cheek plates; ratio of preopercular height to eye diameter 2.9-3.(Weber, 1991) 13.SL/HL = 2.7-3.0;SL/interdorsal length = 5.9-8.Diagnosis.Pterygoplichthys punctatus can be separated from all other Pterygoplichthys except P. weberi by having the buccal papilla divided medially and lobulate (vs.entire and simple, Fig. 1, or lobulate but not divided medially).
Pterygoplichthys punctatus can be separated from P. weberi by having the buccal papilla deeply divided at all ages (vs.shallowly divided in adult, more deeply divided in juvenile), by having many spots on the abdomen and the fin bases (vs.few spots), by having a narrower body (SL/cleithral width 3.6-4.0vs. 3.3-3.4),and by having the lateral keel odontodes sloped posteriorly (vs.almost perpendicular to the plates) and shorter than the lateral-line plates (vs.longer than lateralline plates in adult).
Pterygoplichthys punctatus can be further separated from P. scrophus, P. gibbiceps, P. xinguensis, P. lituratus, and P. parnaibae by lacking an elevated supraoccipital crest (vs.having an elevated supraoccipital forming an obvious crest higher than the plates in the nuchal region); 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. zuliaensis by having a greater HL to interorbital width ratio (2.3-2.6 vs. 2.0-2.2);from P. multiradiatus by having usually 11 dorsalfin rays (only 3 of 27 with 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.no hypertrophied cheek odontodes).
Description.Member of Hypostominae: Pterygoplichthyini: Pterygoplichthys as diagnosed by Armbruster (2004).Morphometric data given in Table 1.Largest specimen 205.1 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 slightly hypertrophied 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 middorsal plate series; keel on remaining plates of mid-dorsal plate series ventral to that of keel on anterior three plates.
Nares separated by short flap of skin held erect in life.
Table 1.Selected morphometrics of Pterygoplichthys punctatus (N=27 except D/K, N=24) and P. weberi (N=11 except D/K, N=7).The letters refer to codes for measurements in Boeseman (1968).Evertible cheek plates with zero to three 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, usually 11 dorsal-fin rays (three of 27 with 12); 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.Pelvicfin spine thin, flexible, reaches barely to base of anal fin.Anal fin with relatively strong, unbranched first ray supporting odontodes.Adipose fin consisting of single median preadipose plate and strong, pointed spine; adipose-fin membrane not reaching procurrent caudal-fin spines.Dorsal fin II,11, pectoral fin I,6, pelvic fin I,5, anal fin I,4, caudal fin usually I,14,I (one specimen I,13,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; 20-36 dentary teeth, 19-38 premaxillary teeth.Median plates 26-29 (mode 28), adipose-caudal plates four to six (mode five), anal-caudal plates 11-13 (mode 12), dorsal-adipose plates five to seven (mode six).Buccal papilla lobulate and divided medially (Fig. 1a).

Color in alcohol.
Body and fins light brown to gray and covered with black spots.Spots smallest on snout, progressively larger to caudal peduncle; spots on fins nearly as large as eye.Venter covered with discrete (uncoalesced) spots; spots smallest on throat and becoming progressively larger to interpelvic area.Spots proportionally larger and more distinct on juvenile.Caudal peduncle lighter ventrally than dorsally.
Range.Known from the rio Madeira drainage and the rio Urubu of Brazil (Fig. 4).Weber (1992) additionally notes localities in the rio Purus and the rio Tocantins basin; however, we did not confirm these identifications.Also, not all specimens available to Weber (1991Weber ( , 1992) ) from the upper Amazon were available to us, and their identity needs to be verified.

Pterygoplichthys weberi, new species
Fig. 5 Holotype.ICNMHN 13455, holotype, 191.4  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 3.3-3.4vs. 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-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.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°f rom 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.
Etymology.Named for Claude Weber of the Muséum d'histoire naturelle, Geneva, for his fine work on Pterygoplichthys and his contributions to loricariid systematics.

Discussion
Pterygoplichthys punctatus and P. weberi can be diagnosed from all other hypostomines examined by the presence of a complex and bifurcated buccal papilla.The function of the buccal papilla is unknown, but the structure is widely variable, and sometimes absent, in loricariids (Armbruster & Page, 1996;Armbruster, 2003).The rugose texture of the buccal papilla suggests that it is covered in taste buds and func-tions as an accessory sensory organ.In some juvenile specimens, the buccal papilla has not yet developed its rugose condition, and an ontogenetic change takes place in P. weberi in which the juvenile has a deeply divided buccal papilla, and the adult has a shallowly divided papilla.
Pterygoplichythys weberi is easily diagnosable from P. punctatus by color, buccal papilla condition, and keel odontodes.It also appears to be wider than P. punctatus, as expressed by SL/cleithral width; however, only 11 individuals of P. weberi were available for examination, and additional data are needed on body shape.
Pterygoplichthys punctatus is most similar in color pattern to P. multiradiatus from the Orinoco; however, adult P. multiradiatus never develop hypertrophied odontodes on the cheek and lack the bifurcated buccal papilla.The color pattern of P. punctatus is similar also to that of the trans-Andean P. undecimalis and P. zuliaensis, and to that of P. etentaculatus from the São Francisco, but these species differ in body shape and distribution of odontodes as described above.