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Ichthyol. Explor. Freshwaters,Vol. 18,No. 2, pp. 163-174,6 figs., I tab.,June 2007 @2007 by Verlag Dr. Friedrich Pfeil, Miinchen, Germany - ISSN0935-9902

Two new speciesof Pseudflncistrusfrom southern Venezuela (Siluriforrnes: )

Nathan K. Lujan*, JonathanW. Armbruster* and Mark H. Sabaj**

Two new speciesof Pseudancistrusare describedfrom the upper Rio Orinoco and Rio Negro in Southern Vene- zuela.Pseudancistrus pectegenitor was collectedin the main channel of the Rio Orinoco near the mouth of the Rio Ventuari and in the middle reachesof the Rio Casiquiare.It differs from congenersby having 10-11dorsal-fin rays (vs. seven),adpressed cheek odontodes reaching to three or more plates beyond the opercle in adults (vs. maximally to rear edge of the opercle),plates of ventral row of caudal peduncle with dorsal laminae strongly concave,accentuating the medial keel of the ventral plate row (shared with P. sidereus),and large oral papillae internal to the dentary tooth cup (shared wilh P. coquenani,P, orinoco,and P. yekuana).Pseudancistrus yekuana is known only from the type locality, immediately upstream of Salto Tencua in the upper Rio Ventuari. It differs from congenersby having large oral papillae internal to the dentary tooth cup (shared with P. coquenani,P. ori- noco,and P. pectegenitor),lowerlip reaching to middle of pectoral girdle (vs. to anterior edge of pectoral girdle), pectoral-fin spine maximally reaching posterior baseof the pelvic-fin spine when adpressedventral to the pelvic fin (vs. at least halfway through pelvic-fin insertion) and by severalmorphometric differences.

Sedescriben dos especiesnuevas del g6nercPseudancrsfrls (familia Loricariidae) de la parte alta del Rio Orinoco y del Rio Negro en el sur de Venezuela.Pseudancistrus pectegenitor fue colectadoen el canal principal del Rio Orinoco cercade la boca del Rio Ventuari y en los tramos medios del Rio Casiquiare.Esta especie difiere de sus cong6nerespor presentar10-11 radios en la altea dorsal (vs. siete),odontodos en la mejilla alcanzandotres o mds placaspor detr6s del op€rculo en adultos cuando seencuentran en posici6n retractada(vs. no extendi6ndosemas alld del borde posterior del op€rculo), placas de la fila ventral del pedrinculo caudal con liiminas dorsalesque presentanuna profunda concavidad y acent(an la quilla medial de la fila de placasventral (condici6n compar- tida con P.sidereus),papilas orales de gran tamafro situadas en posici6n interna a la caja dentaria (condici6n compartida con P. coquenani,P . orinoco,and P. yekuana).Pseudancistrus yekuana se conocerinicamente de su loca- lidad tipo, en las inmediacionessuperiores al Salto Tencuaen la parte alta del Rio Ventuari. Estaespecie difiere de sus cong6nerespor presentar papilas orales de gran tamafro situadas en posici6n interna a la caja dentaria (condici6n compartida con P. coquenani,P. orinoco,and P. pectegenifor),labio inferior extendi6ndosehasta la parte media de la cintura pectoral (vs. alcanzandorinicamente el borde anterior de la cintura pectoral), espina de la aleta pectoral alcanzandoa lo sumo el borde posterior de la base de Ia espina p6lvica cuando se encuentraen posici6n extendida hacia la aleta p€lvica (vs. alcanzandopor lo menos hasta la parte media del inserci6n de la aleta p6lvica) y por varias diferenciasmorfom€tricas.

Department of Biological Sciences,Auburn University,33l Funchess,Auburn, AL 36&{9,USA. E-mail: NKL: [email protected],JWA: [email protected] Academy of Natural Sciences,1900 Beniamin Franklin Parkway, Philadelphia, PA 19103,USA. E-mail: [email protected]

Ichthyol. Explor. Freshwaters,Vol. 18,No.2 164

Introduction proximally along each dentary, internal to the tooth cup (Fig. 1). These papillae vary within The Proterozoic outcrops in the upper Orinoco individuals in thosespecies that have them, rang- are an incredibly -rich and historically ing from a single large papilla to one to three under-studied habitat for loricariid ,as clusters of smaller papillae. Comparative speci- evidencedby this and severalother recentspecies mens of other loricariids examined are listed in descriptions(for example,Werneke et a1.,2005a; Armbruster (2004a-b)and a list of members of Werneke et al., 2005b;Armbruster, 2005; Arm- Pseudancistruswith dentary papillaeis below. A bruster et a1.,2007).Recent fieldwork in Amazo- principal components analysis for the morpho- nas, Venezuelaby AUM, ANSP, and MCNG has metric data was performed using a covariate yielded several hundred lots of loricariids col- matrix and log-transformedmeasurements in JMP lected largely from rocky habitats in the upper (Vers.5.01a, SAS Institute,2002).The data for Rio Orinoco,upper Rio Negro, and many tributar- P. coquenaniand P. orinocowere combinedin the ies thereof.Included in theseare at leasttwo new PCA becausethere are no discernablemorpho- speciesof. Pseudancisfrus with enlarged dentary metric differencesbetween the two species. papillae. Armbruster (2004a-b)redescribed and diag- nosedthe genusPseudancistrus and treatedLithox- Pseudancistruspectegenitor, new species ancistrusand Guyanancrsf rus as junior synonyms. (Figs.2-3) Armbruster (2004b)listed 14 nominal speciesin Pseudancistrusof which 12 are currently consid- Holotype. MCNG 54797(formerly AUM42130), ered valid. Of these,two species,P. coquenaniand 241.6mm SL; Venezuela:Amazonas: Rio Casiq- P. orinocohavelarge oral papillae on eachdentary uiare,bedrock in stream,73km NE of SanCarlos just internal to the tooth cup (Fig.1). This char- de Rio Negro (2o21'09"N66'34'31"W); 9 March acterwas usedby Isbnickeret al. (1988)to propose 2005,N. K. Lujan, D. C. Werneke,M. H. Sabaj, the new genusLithoxancistrusfor their new species M. Arce, R. Betancur& T. E. Wesley. L. orinoco;however, dentary papillae also occur in Chaetostomaand some Cordylancistrus(Arm- Paratypes.AUII{ 42202,227.0mm SL;Venezuela: bruster, 2004a-b;fWA, pers. obs.). The purpose Amazonas:Rio Casiquiare,153 km NE of San of this paper is to describe two new speciesof Carlosde Rio Negro (247'56"N 66"00'23"W);24 Pseudancistrusthat share with P. coquenaniand March 2005,N. K. Lujan et al. - AUM 43'192(cs.), P. orinocothe presenceof dentary papillae. One 173.6mm SL;Venezuela: Amazonas: Rio Orinoco, of these species,P. pectegenitor,is large with an beachand bedrock outcropping, 50 km E of San increased number of dorsal-fin rays, making it Fernandode Atabapo.- ANSP 182801(formerly very easy to diagnose from other Pseudancistrus 4UM421.8'D,225.1mm SL;Venezuela: Amazonas: despite a sample size of only four adults. The Rio Orinoco, Punto de Maraya, Isla Maraya, second species,P.yekuana, is small and very 80.8km W of SanFernando de Atabapo(4'01'23" similar to P. orinoco.Infact, P. yekuanamay not N 56'58'19"W); 31 March 2005,N. K. Luian et havebeen easily diagnosed from P. orinocoif they al. were not sympatric. Diagnosis. Pseudancistruspectegenitor can be diagnosedfrom all other Pseudancistrusby having Methods 10-11dorsal-fin rays (vs.7) and adpressedcheek odontodes reaching to three or more plates be- Counts and measurements follow Armbruster yond the opercle in adults (vs. maximally to rear (2003).Character numbers and states are from edge of opercle); from all other described Pseu- Armbruster (2004b)and are presentedin paren- dancistrusexcept P. sidereusby having the plates theses.One specimenof eachspecies was cleared of the ventral row of the caudal peduncle with and stained (cs.) for examinationof bone and dorsal laminae strongly concave, accentuating cartilageusing the methodsof Taylor & Van Dyke the medial keel of the ventral plate row (vs. ven- (1985).Institutional abbreviations are as in Levi- tral plate row slightly convex;Armbruster,2005); ton et al. (1985).Dentary papillae are defined as and from all Pseudancisfrusexcept P. coquenani, a simple papilla or clusters of papillae located P.orinoco,and P. yekuanaby having large oral

Luian et al.: Twonew Pseudancistrus 165

Fig. 1. Mouth of; a, Pseudancistrusyekuana; and b P. pectegenitor.Arrows point to dentary papillae.

papillae proximally on eachdentary just internal as wide as head. Tooth cups of upper jaw slight- to the tooth cup (vs.papillae absent;Fig. l). Pseud- ly wider than those of lower jaw. Premaxillary ancistruspectegenitor can be further diagnosed teeth 119-164(median 131);dentary teeth 126-134 from P. coquenani,P.orinoco, and P. yekuanaby (median 128).Teeth villiform and bicuspid with having a larger pectoral-fin spine (38.342.2Vo SL medial cusp larger than lateral cusp. Worn teeth vs.22.0-31,.4)and from P. coquenaniand P. orino- with cuspsapproachingequal length. Lateral edge co by having a smaller head-dorsal length (5.6- of oral disk extending slightly beyond lateral 6.8Vo SL vs. 8.0-12.2). margins of head. Maxillary barbel short and oc- casionally bifurcated distally. Ventral surface of Description. Morphometrics presented in Ta- lips papillose. Papillae increasing in size and ble 1. Meristics basedon four individuals. Large decreasingin density from labial rictus (smallest loricariids, largest specimen241.5 mm SL. Body and most dense),to regions proximal and poste- squat with large, dorsoventrally depressedhead rior to dentary tooth cups (intermediate), to and stout trunk. Snout sloped at -30o angle to larger and less-denselyspaced papillae restricted orbit; dorsal profile slightly arched from orbit to to band along middle of lower lip; posteroventral posterior insertion of adipose fin with depth at edge of lower lip devoid of papillae. Dentary adipose fin shallower than depth at orbit; body papillae present. Buccal papilla present, with a depth greatestin nuchal region. Eyesset far pos- long stalk-like base. teriorly on head with orbits oriented at -45o from Dorsal fin II,10; dorsal-fin spinelet short and sagittal plane. Ventral profile angled slightly V-shaped; dorsal-fin lock functional. Dorsal fin downward from snout to coracoid, then flat to large, as high or higher than body depth. Ante- caudal fin. rior dorsal-fin rays longer than dorsal-fin spine Anterior margins of snout with small to me- and decreasingin length posteriorly, forming a dium-sized hypertrophied odontodes. Evertible gentle arc towards adiposespine. Pectoral fin I,6; cheekplates with highly hypertrophied, distally pectoral spine extending beyond posterior inser- hooked odontodes(range M-57), longest extend- tion of pelvic fin when adpressed.Pectoral-fin ing beyond posterior edge of pectoral fin. Head spine stout with odontodesincreasing in sizeand contours smooth with slightly raised supraorbital density distally. Distal odontodesvery hypertro- crest from anterolateralcorner of nares to poste- phied, intermediate in size to those of evertible rior edge of pterotic. Lateral surfacesof supraor- cheekplates and those of snout. Anterior pectoral- bital crest covered with odontodes slightly en- fin rays as long as pectoral-fin spine, decreasing larged relative to those on surrounding plates. to less than half of length of spine posteriorly. Nuchal region forming a broad hump slightly Pelvic fin I,5; pelvic-fin spine stout, reachingend raised above supraoccipital and dorsal-fin base. of baseof anal fin when adpressed;anterior pel- Mouth large with broad, straight jaws nearly vic-fin rays as long as or longer than pectoral-fin

Ichthyol. Explor. Freshwaters,Vol. 18,No.2 Fig. 2. Pseudancistruspectegenitor, AUM 42202,227 .0 mm SL; Venezuela:Rio Casiquiare;freshly dead. Photo by N. K. Luian. spine with posterior margin of fin curving out Color. Alcohol preserved adults with gray-tan beyond posterior tip of spine. Anal fin I,5; ante- to charcoalground color on head and plated re- rior anal-fin rays slightly longer than unbranched gions of body. Unplated ventral surfaceof snout anal-fin ray, posterior anal-fin rays slightly short- and outer surface of upper lip gray brown; un- er than unbranched anal-fin ray. First anal-fin plated breast and abdominal region lighter, pale pterygiophore not exposed to form a plateJike dusky white and without distinct markings. structure.Adipose-fin spinestraight with adipose Papillated surfacesof ventral oral disk pale white membranenot extendingbeyond posterior extent with dusky posterior margin (darkest near base of spine. Caudal fin 1,1.4,I;caudal-fin spines of maxillary barbel).Lighter specimenswith faint longer than caudal-fin rays. Dorsal and ventral pattern of small light spots and fine vermicula- procurrent caudal-fin rays four to five. Posterior tions on head (particularly pterotic region), body caudal-fin margin straight. Rays of all fins sup- plates, and skin along dorsal-fin insertion; and porting small odontodes. gray-tan body plates outlined with darker gray- Body broad at base and compact in length, brown skin. Dorsal-, adipose-,caudal- and anal- with short and stout caudal peduncle. Lateral fin spines, rays and membranesnearly uniform body plates in median series25. Ventral plates gray brown, without conspicuouspattern. Paired forming right angle on caudal peduncle with fins similar or with faint pattem of small light dorsal lamina of plates concave, accentuating spots and vermiculations on rays and to a slight- strong rounded keel along lower portion of cau- ly lesser degree on membranes.Hypertrophied dal peduncle. Plates in middorsal row weakly odontodes orange to straw colored. Small pre- arched submedially forming low ridge from servedjuveniles (< 13 mm SL) with body more or cleithrum to posterior insertion of pelvic fin. Five lessuniformly brown exceptventral surfacefrom rows of plates on caudal peduncle. Abdomen oral disk to vent white; fins darker brown with naked. distal marginsand/or tips hyaline (depigmented).

Luian et al.: Two new Pseudancistrus 767

Fig.3. Pseudancistruspectegenlfor, holotype, MCNG 54797,241.6 mm SL; Venezuela:Rio Casiquiare.Photos by M. H. Sabaj. lchthyol.Explor. Freshwaters, Vol. 18, No. 2 768

In live adults ground color dull olive to charcoal known to exhibit such armament although males with lighter spots and vermiculations yellowish may be better adorned than females(Armbruster to tan (Fig.2). & Provenzano,2000).The only specimenofP. pec- tegenitorcollected in an ecologicalcontext allow- Sexual dimorphism. Darwin (1882)used Psezd- ing reasonablededuction of sex, a presumably ancistrusbarbatus to illustrate an example of adult male ([UM42202,227.0mm SL) collected sexual dimorphism in which males are adorned while guarding young in a nest, exhibited extreme with highly hypertrophied odontodes and females hypertrophy of odontodeson the evertible cheek are not; however, both sexesin P.barbatusand platesand, to a lesserextent, on the pectoralspines other speciesof. Pseudancistrus are more recently and snout. A single immature P. pectegenitorin-

Table 1. Selectedmorphometrics ol Pseudancistruspectegeiltor and P. yekuana.Landmarks represent the two landmarks the measurementis between (seeArmbruster, 2003).

P. pectegenitor P. yekuana n=4 n=3 landmarks ranSe SD range mean SD Standard length (mm) 1,-20 173.6-241,.621,6.8 29.7 32.742.7 38.6 5.2 In percents of standard length Predorsallength 1-10 4.0-M.2 43.5 1.0 49.1-50.1 49.6 0.5 Head length 1-7 35.9-38.1 37.0 0.9 39.943.8 42.4 2.1, Head-dorsal length 7-70 5.6-6.8 6.2 0.6 6.0-8.0 6.9 1.0 Cleithral width 8-9 29.2-34.1. 31,.4 2.1 28.6-30.4 29.3 1.0 Head-pectorallength 1-12 30.6-32.9 31.9 1.2 38.3-38.9 38.5 0.3 Thorax length 1,2-'t3 22.9-25.1 24.0 1.0 22.8-24.5 239 0.9 Pectoral-spine length 1.2-29 38.342.2 40.1 1,.9 22.0-24.6 22.9 1.5 Abdominal length 13-1,4 22.3-24.7 23.5 1.0 17.2-22.7 79.4 2.9 Pelvic-spinelength 13-30 23.1-27.4 24.7 2.0 2'1,.9-23.6 22.6 0.9 Postanallength 14-15 27.8-37.5 29.5 1.5 28.2-30.0 29.2 0.9 't1,.2-13.3 Anal-fin spine length 1,4-31, 1,2.2 1.0 7.0-9.6 8.4 1.3 Dorsal-pectoral depth 1,0-1,2 24.6-26.4 25.7 0.8 25.1-27.4 26.4 1.2 Dorsal spine length 10-11 28.8-35.2 32.0 4.5 20.8-22.9 22.2 1,.2 Dorsal-pelvic depth 10-13 22.6-25.5 23.9 1.5 1,9.9-20.8 20.5 0.5 Dorsal-fin base length 10-16 34.0-38.0 35.6 1.8 21,.5-22.2 21,.8 0.3 '1,0.2-1,2.1, Dorsal-adiposedepth tG17 8.8-11.1 r0.2 1.0 1,1,.3 1.0 Adipose-spine length 17-'t8 5.6-7.8 6.6 1.1 7.8-9.5 8.9 0.9 Adipose-upper caudal depth 1,7-1,9 8.9-10.5 9.6 0.8 15.0-15.5 15.8 0.8 Caudal peduncle depth 15-19 1,2.1-13.6 1,2.7 0.7 10.0-11.6 10.9 0.8 Adipose-lower caudal depth 1,5-17 1,7.4-1,8.5L7.8 0.5 19.9-22.7 2'r.5 1.s Adipose-anal depth 14-'.17 18.9-20.5 19.8 0.7 17.0-17.7 17.3 0.4 Dorsal-anal depth 1,4-16 1,4.7-16.4 15.5 0.8 74.0-'t4.7 14.3 0.4 Pelvic-dorsaldepth 13-16 30.0-34.8 32.3 2.5 20.9-22.8 22.2 1.1 In percents of head length Head-eyelength 5-7 25.3-29.9 27.5 1,.9 24.6-3',r.1 28.4 3.4 Orbit diameter +5 1,4.6-1,6.0 1s.0 0.6 13.1-13.8 13.4 0.4 Snout length 74 65.7-69.7 58.0 7.4 68.6-74.0 70.8 2.8 Internareswidth 2-3 1,7.0-1,2.2 77.4 0.5 9.1-10.2 9.6 0.6 Interorbital width 5-6 33.041,.7 36.8 3.6 39.0-40.1 39.7 0.6 Head depth 7-1,2 62.8-64.4 63.4 0.7 54.0-56.9 55.5 1,.4 Mouth length t-24 49.4-58.4 52.3 4.1, 70.5-77.2 73.8 3.4 Mouth width 21-22 62.3-75.9 70.3 6.2 73.3-78.0 75.6 2.4 Barbel length 22-23 9.3-10.9 10.1 0.8 5.4-9.7 8.1 2.3 Dentary tooth cup length 25-26 23.0-27.2 24.8 1.8 24.9-37.3 28.7 3.4 Premax.tooth cup length 27-28 21,.5-26.5 24.9 2.3 27.0-28.3 27.8 0.7

Luian et al.: Two new Pseudancisttus r69 dividual (AUM 43192,cs.,'173.5 mm SL) of unde- 12" termined sex lacked especially hypertrophied odontodes.Two other individuals (ANSP43192, 225.1;MCNG 54797,247.6mmSL)with hyper- trophied odontodes similar to that of the male above were also collected but their sex was not determined.

Range. Found in the main channel of the Rio Orinoco above RaudalesAutures (near mouth of Rio Ventuari), and in the Rio Casiquiare, Ama- zonas,Venezuela (Fig. 4).

Habitat. All specimenscollected from flowing water associatedwith large rock outcropsin main river channel. One specimen collected at night with a seine in swift shallow run over bedrock. All others collected by hand from within rock crevices. 63" Fig.4. Rangeof Pseudancistruspectegenitor (I,!) and Reproductive biology. In the majority of lori- P.yekuana(O,o), open symbolsshow type localities. cariids for which parental careis known, the male Basemap by M. I. Weitzman. is the caregiver (Evers & Seidel, 2005; Gross & Sargent,1985). One presumablyadultmale (AUM 42202,227.0 mm SL) was collected while caring Etymology. From the Latin pecten,rrreaning quill, for young in a vertical crack in bedrock immed! and genitor, meaning father, in referenceto the ately below the water's surface(Fig.2). Crevice hypertrophied odontodes of the snout, pectoral spawning is common among the spine,and evertiblecheek plates, and the fact that (Suzuki et al., 1985)and almost universal among one presumably adult male was collected while the (Evers& Seidel,2005).Water level caring for a large brood of young. A noun in ap- in the Casiquiare at this locality would have re- position. cently risen with the onsetof the rainy seasonjust a few weeks before, when this individual likely spawned. Seasonalspawning timed to coincide Pseudancistrusyekuana, new species with the onset of the rainy seasonhas been ob- (Fig.s) served in Hypostomusluetkeni in the Paraiba do Sul in (Mazzoni& Caramaschi,1,997),but Holotype. MCNG 54798(formerly AUM39473), would be in contrast to the aseasonalbreeding 42.7 mmSL;Yenezuela:Amazonas: Rio Ventuari, cycle that Winemiller (1989)observed for hypos- above Salto Tencua, 58 km ESE of San Juan de tomines (Ancistrussp. and Hypostomusargus) in Manapiare(5'02'52"N 65'3 6' 57"\N); 21 April 2004, the piedmont of northern Venezuela.An incred- N. K. Lujan, O. Le6n, A. Luna & A. Yarumare. ible number of juveniles (n=485, SL<13 mm) were collectedwith the father, and dozens more Paratypes. AUM 39473, 2, 40.5-35.0 mm SL (1 cs.); from the same nest were not collected. Among ANSP 182802,32.7mm SL,same data asholotype. the Hypostominae, this level of fecundity is less than some (e.g., Rhinelepisaspera, a broadcast Diagnosis. Pseudancistrusyekuana can be diag- spawner from which have been recorded up to nosedfrom allother PseudancistrusexceptP. coque- 181200 oocytes,avg.4T 370; Agostinho, 1985), but nani, P.orinoco,and P. pectegenitorby having more than others (e.g.Ancistrus sp. reported by dentary papillae (vs. dentary papillae absent; Sabajet al.,1..999,to have 20-200offspring, and Fig. 1); from P. coquenani,P. orinoco,and P. pecte- Lithoxusreported by Armbruster,'1998, to have genitor by having the lower lip reaching to the 15-17mature oocytesin two females). middle of the pectoral girdle (vs. to anterior edge of the pectoral girdle), by having the pectoral-fin

Ichthyol. Explor. Freshwaters,Vol. 18,No. 2 170 spine maximally reaching the posterior edge of Dorsal fin ll,7; dorsal-fin spinelet short and the pelvic-fin spine when adpressedventral to V-shaped;dorsal-fin lock functional. First dorsal- the pelvic fin (vs. at least halfway through pelvic fin ray slightly longer than dorsal-fin spine; re- fin); and from P. pectegenitorby having 7 dorsal- maining rays decreasingin length. Last dorsal-fin fin rays (vs. 10-11)and by having the evertible ray when adpressedreaching insertion of adipose- cheek odontodes maximally reaching the poste- fin spine. Pectoral hn 1,6;pectoral spine maxi- rior end of the opercle (vs. three or more plates mally reaching posterior edge of pelvic-fin spine behind the opercle).In addition, severalmeasure- when adpressedventral to pelvic fin. Anterior ments serve to separateP. yekuanaf.rom P. coque- and ventral surface of pectoral-fin spine with nani,P. orinoco, andP. pec t e genit or ; however,these odontodesalong entire length, slightly hypertro- ratios havelittle predictive power given that there phied distally. Pelvic fin I,5; first pelvic-fin ray as are only four specimens of P. yekuanaknown: long as pelvic-fin spine and remaining rays de- predorsallength (49.1-50.1 7o SL in P. yekuanavs. creasing in length. Anal fin I,5; first anal-fin 47.5-46.0),head length (39.9-43.8Vo SL vs. 31.2- pterygiophore not exposedto form a plate. Adi- 38.1),head-pectoral distance (38.3-38.9 VoSL vs. pose-fin membrane extending slightly posterior 26.8-32.9),and mouth length (70.5-77.2 % HL v s. to adipose-fin spine. CaudaI finl,1,4,l; caudal fin 49.4-67.5). emarginate. Dorsal procurrent caudal-fin rays five; ventral procurrent caudal-fin rays four. Rays Description. Morphometrics presented in Ta- of all fins supporting odontodes. ble 1. Meristics basedon four individuals. Fairly small loricariids, largest specimen 42.7mm SL. Color. Alcohol preserved specimenswith gray- Head distinctly large relative to body, with long, brown ground color on head and sides,dorsally spatulate snout. Small eyes placed high and far with faint pattern of three to four lighter, tan back on head with orbits oriented at -45o to saddles,the first either at the dorsal-fin origin or sagittal plane. Dorsal contour of head smooth beneath the middle of its insertion; posterior except for slightly elevated plateau formed by ventral sides similarly with fain tan bars, some modest supraorbital crestsand elevated,flat in- united midlaterally with saddles(lighter barsand terorbital region. All dorsal and lateral surfaces saddles more evident in smaller specimens). of head plated and with small odontodes.Odon- Undersurfaceslighter, pale tan on unplated breast todes slightly larger along anterior and lateral and abdomen becoming dusky with scattered margins of snout, along midline of snout over melanophoresnear vent and onto plated caudal mesethmoid,and along supraorbital crest poste- peduncle.Oral disk with papillated surfacespale rolateral to nares. Evertible cheek odontodes white and dusky posterior margin (darkest near longest,numbering 11-13(median 12). baseof maxillary barbel). All fin spinesand rays Dorsal profile forms gentle arc from anterior with alternating wide dark and narrow light margin of snout to posterior processof supraoc- bands (pattern most evident in dorsal fin, least cipital, horizontal to insertion of dorsal-fin spine, evident in pectorals);fin membraneshyaline or then ventrally sloping at shallow angle to inser- with melanophores scatteredalong rays. Small tion of dorsal caudal-fin spine. Ventral profile of but distinct black spot present at baseof anteri- head sloped slightly downward from snout to ormost dorsal-fin membrane in largest speci- coracoid such that ventral surface of large oral men. disk is even with flat, horizontal ventral profile of trunk. Median plates 22-24 (mode=24). Five Sexual dimorphism. None observed. caudal peduncle plate rows. Abdomen naked. Mouth largewith lips occupyingalmost entire Range. Known only from the Rio Ventuari im- ventral surface of head. Maxillary barbel short mediately above Salto Tencua (Fig. a). The rang- and connectedalong most of length to lower lip es of at least four other fish species(all unde- by flap of skin. faws wide with slight angle of scribed) are currently restricted to the Ventuari tooth cupsand inward curvatureof tooth arrange- above Salto Tencua: Lithoxus sp., Harttia sp., ment in ventral view. Left premaxillary teeth Brachyglanissp., and Geophagussp. Thus, Salto 50-69(median 67).Left dentary teeth 63-71(me- Tencua may function as a partial faunal barrier. dian 55). Dentary papillae present. Buccal pa- The barrier does not appear to be complete be- pilla present,with long, stalk-like base. causePseudancistrus orinoco, a speciesvery simi-

Luian et al.: Two new Pseudancrstrus 1,71

Fig. s. Pseudancistrusyekuana, holotype, MCNG 54798,42.7 mm SL; Venezuela:Rio Ventuari. Photos by M. H Sabaj. lar to P. yekuana,was collected both above and Etymology. The speciesname, yekuana, refers to below the falls. the Ye-kuana,the indigenous peoplesinhabiting the upper Rio Ventuari and other areasof south- Habitat. All individuals collectedby castnet from ern Venezuelaand northern Brazil, whose gener- torrential sheet flow over bedrock in the main ous cooperation made this researchpossible. channel of the upper Ventuari. Treatedas a noun in apposition.

Ichthyol. Explor. Freshwaters,Vol. 18,No. 2 172

Dentarytooth cup L. Headdorsal D. more dorsal-fin rays (Armbruster, 2004b). Al- L. Dorsal-adiooseD Plemaxillarytooth cup though an increased number of dorsal-fin rays 0.4 tet may be useful for diagnosing genera (i.e., Ptery- 0.3 lB'fi8= goplichthys)and clades within Hypostominae(i.e., 0.2 Acanthicusgroup, Chaetostomagroup); it seems =; that in the caseof P. pectegenitor(as in Pogonopo- 0.1 !- P. pectegenitor maobscurum), the increasednumber of dorsal-fin N o0 o@ o- OD rays is an autapomorphy diagnostic only at the =g -0.1 DO specieslevel. Pseudancistruspectegenifor shares a P. coquenani + -0.2 o number of synapomorphieswith the genusPseud- P. oinoco ancistrus,therefore erection of a new genusis not -0.3 to P. yekuana l! warranted. Indeed, much of the morphology of -0.4 Vr- P.pectegenitoris rather autapomorphic.For ex- -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 amples, there are a very high number of teeth, PC3 the body seemsrelatively short, and the cheek Fig. 6. PrincipalComponents Analysis of speciesof odontodes are very elongate whereas the trend Pseudancistruswith dentarypapillae. Strongest loading in Pseudancistrusis towards the reduction of the charactersshown with theirdirection of influence. size of the cheekodontodes. Regardless, P. pecte- genitorhas all but one of the synapomorphiesof Discussion Pseudancistrusand it shares the synapomorphy of the dentary papillae with P. coquenani,P. ori- Armbruster (2004a)diagnosed Pseudancistrus with noco, and P.yekuana,a characteristic seen else- the following: no suture between pterotic-supra- where only inChaetostomaand some Cordylancis- cleithrum and hyomandibula (34-0, reversal; trus. characternumbers and statesfrom Armbruster, If the specimensof Pseudancistrusyekuana were 2004b),no contact of the hyomandibula with the not collected sympatrically with P. orinocothey prootic (35-1), straight, spoon-shaped anterior might not havebeen readily separatedas a unique processof metapterygoid (58-1),nasal bone not species.The two speciesare similar in general much wider than laterosensory canal running form and color; however, seeingthe two species through it (105-0),sphenotic not contacting pos- side by side in the same collection makes the teriormost infraorbital externally (117-1),and a identification of P.yekuanaas a new species short ventral ridge on the pelvic basipterygium rather obvious. The shape of P.yekuanais also (172-1,lostin some species).Pseudancistrus pecte- quite different from the other speciesof Pseudan- genitor has four of these five characteristics, cistrusassuggested by the Principal Components varying only in that the sphenotic does contact Analysis(Fig.6). Although this PCA is basedon the posteriormost infraorbital externally. Pseud- few individuals of P. yekuana,the degree of dif- ancistrusyekuana also has four of thesecharacter- ference between it and the other Pseudancistrus istics; varying only in that there is a suture be- in the analysisis large, and presumed indicative tween the pterotic-supracleithrum and the hyo- of true differences. mandibula; however, the suture present is very Pseudancistrusyekuana appears to be fully weak. mature at a small size. The cleared and stained Pseudancistruspectegenitor is unique among specimen(35.0 mm SL)had ova more mature than Pseudancistrusin having an increasednumber of would be seen in juveniles, and the largest dorsal-fin rays (i.e., greater than seven). An in- specimenis only 42.7mm SL,whereas the largest creasednumber of dorsal-fin rays is not common specimen of either P. orinocoor P. coquenaniex- in hypostomines;however, there are several ex- aminedis 105.8mm SL.The dorsalsurface of the amples:one speciesof Pogonopomahasten dorsal- head supportsmore odontodesat a smallersize fin rays (Quevedoand Reis,2002), Pterygoplichthys in P. yekuanathan in P. orinoco.The 42.7mm SL usually has 10 or more dorsal-fin rays, and the type of P.yekuana,for example, has the head Acanthicusgroup (Acanthicus,Leporacanthicus, fully supporting odontodeswhile similarly sized Megalancistrus,and Pseudacanthicu)and the Cha- P. orinocofrom the samelocality have large naked etostomagroup (Chaetostoma,Cordylancistrus, patches on the frontal and supraoccipital. Sev- Dolichancistrus,and Leptoancistrus)have eight or eral morphometric ratios separatedP.yekuana

Luian et al.: Two new Pseutlancistrus 173

and P. orinoco; however, only three specimens of Thanksespecially to O. Le6n whose skilled castnetting P. yekuana were measured, and these characters collected the specimensol Pseudancistrnsyekuana. are suspect until more specimens become avail- Thanks to M. Arce, R. Betancur,A. Luna, RafaelPajua, L. deSouza,T. Wesley,M. Grant, E. Richmond, able. The snout of P. yekuana is much more elon- J. Vala- dez, D. Brooks, F. Brito, L. Camico, O. SantaElla, and gate when compared against specimens of similar D. Werneke for aid in collecting specimens and R. size, the pectoral fins much shorter, and the Betancurfor the Spanishabstract. lower lip is so long that it almost reaches beyond the pectoral girdle (see Diagnosis). Literature cited Comparative material, Pseudancistruscoquenani: Yen- ezuela:AMNH 31023,6, 53.9-62.9mm SL; Bolivar: Rio Agostinho, A. A. 1985.Estrutura da populaqdo,idade Paraguaat GusanoRapids, Rio Caronidr., 1-1.5hours e crescimentode Rhinelepisaspera (Agassiz,7829) upriver from Rio Carapo mouth (5"30'N 63"36'W).- (Osteichthyes,Loricariidae) do rio Paranapanema, MCNG "17525,2,@.6-94.4 mm SL; Bolivar: Rfo Caroni Pr. PhD dissertation.Universidade Federalde Sio dr., Rio Supamo 12 km N of la Piedra del Supamo Carlos,56o Carlos. (6'59'N 62"23'W).- MCNG 18339,5, 58.8-94.4mm SL; Armbruster, J. W. 1998.Modifications of the digestive Rio Caroni dr., middle Rio Tocomo below entranceof tract for holding air in loricariid and scoloplacid railway below high tension cables (7"50'40"N 40'63' catfishes.Copeia,'1,998: 663-675. 05"W).- MCNG 18470,6,52.2-62.9mm SL; Bolivar, Rio - 2003.P eckol t ia sabaj i, a new speciesfrom the Guyana Caroni dr., Rfo Claro east of Los Tanques (7"55'20"N Shield (Siluriformes: Loricariidae). Zootaxa, 344:. 63'06'05"W).- NMW 48023,2 syntypes, 75.5-78.6mm 1-72. SL; Bolivar: Rio Caroni dr., Rio Coquenan. - 20Ma. Pseudancistrussidereus, a new speciesfrom P. orinoco:Venezuela: ANSP 1@6N,5,79.i79.0 mm southern Venezuela (Siluriformes: Loricariidae) SL; Amazonas: Rio Orinoco, Raudales de Atures, at with a redescriptionof Pseudancistrus. Zootaxa, 628: Culebra,ca 7 km Sof PuertoAyacucho (5'35'N 67'31'W). 1-15. - ANSP 165824,1,78.1mm SL;Apure: Rio Araucadr., - 2004b. Phylogenetic relationships of the sucker- cafronear El Yagua (7'30'N 68'20'W).- AUM 39479,5, mouth armored catfishes (Loricariidae) with em- 56.7-82.4mmSL, same data as types of P.yekuana.- phasis on the Hypostominae and the Ancistrinae. AUM 39542,5, 67.5-105.8mm SL; Amazonas:Rio Ori- Zoological of the Linnean Society, 141: 1- noco dr., Rio Ventuari at RaudalesTencua, 56 km ESE Journal 80. of San de Manapiare (5'02'59"N 65'37'38"W).- Juan - 2005.The loricariid Iasiancistrus(Sil- {UM42779,1,93.1mm SL;Amazonas: Rio Casiquiare uriformes) with descriptions of two new species. dr., Rio Siapa,rapids 154km E of San Carlosde Rio Neotropical lchthyology, 3: 549-569. Negro(1"36'12"N 65"42'57"W). - AUM 42'1U,1,80.6 mm Armbruster,J.W., N. K. Lujan & D. C. Taphorn.2007. SL; Amazonas:Rio Casiquiaredr., Rio Siapa,Raudales Four new Hypancistrus(Siluriformes: Loricariidae) Gallineta, 142km E of San Carlos de Rio Negro (1'49' from Amazonas,Venezuela. Copeia (in press). 00"N65'47'41"W).-MCNG2020{, 1,61.0 mmSL; Apure: Armbruster, l. W. & Provenzano R. 2000. Four new Rio Capanaparodr., at CORPOVEN camp and Laguna speciesof the suckermouth armored catfish genus Larga,Rio Apure dr. (6'31'50"N67"23'48"W). - MCNG Lasiancistrus(Loricariidae: Ancistrinae). Ichthyo- 21631,1,70.7mm SL; Amazonas:Rio Orinocodr., Rio logical Exploration of Freshwaters,1 1: 241-254. Cataniapo at the bridge just S of Puerto Ayacucho Darwin, C. R. 1882.The descentof man and selection (5'36'N 67'35'30"W).- MCNG 25794,1,48.2 mm SL; in relation to sex, Second Edition, Murray Amazonas:Rio Orinoco dr., Rio Ocamo at Raudal Ar- John London,693pp. ata (3"8"N 64"34'W).- MCNG 30407,2,45.5-58.4mm Evers, H.-G. & I. Seidel 2005.Catfish atlas Volume 1: SL; Amazonas:Rio Orinoco at Raudalesde Atures. South American catfishesof the families Loricari- idae,Cetopsidae, Nematogenyidae and Trichomyc- teridae. Mergus, Melle. Acknowledgements Gross, M. R. & R. C. Sargent. 1985.The evolution oI male and female parental care in fishes.American This project was funded by Planetary Biodiversity In- Zoologist, 25: 807-822. ventory: All Catfish Species(Siluriformes) - PhaseI of Isbriicker, L J. H., H. Nijssen & P. Cala. 7988.Lithoxan- an Inventory of the Otophysi, a 5 year grant through cistrusorinoco, nouveau genre et espEcede poisson- the US National ScienceFoundation to describe all chat cuirass€de Rio Orinoco en Colombie (Pisces, speciesof catfishes(NSF DEB-0315963)and NSF grant Siluriformes,Loricariidae). Reure Franqaise d'Aqua- DEB-0107751to JWA. We would like to express our riologie et Herp6tologie, 15: 13-16 deepest appreciation to D. Taphorn and O. Le6n for Isbrticker I. J. H., I. Seidel,J. P. Michels, E. Schraml & their invaluable help in obtaining permits, logistical A. Werner. 2001. Diagnose vierzehn neuer Gat- support, aiding in fieldwork, and loan of materials. tungen der Familie Loricariidae Rafinesque,1815

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(Teleostei,Ostariophysi). Pp. 17-24 in: R.Stawikowski Suzuki, H.I., A. A. Agostinho & K. O. Winemiller.2000. (ed.), Datz-Sonderheft Harnischwelse 2. Eugen Relationship between oocyte morphology and re lJlmer, Stuftgart. productive strategy in loricariid catfishes of the Leviton, A. E., R. H. Gibbs, E. Heal & H. E. Dawson. Parana River, Brazil. fournal of Fish Biology, 57: 1985.Standards in herpetology and ichthyology: 797-807. Part I. Standard symbolic codes for institutional Taylor, W. R. & G. C. Van Dyke. 1985.Revised proce- resourcecollections in herpetology and ichthyology. dures for staining and clearing small fishes and Copeia, 1985:802-832. other vertebrates for bone and cartilage study. Mazzoni, R. & E. P. Caramaschi.1997. Observation on Cybium, 9:707-1.19. the reproductive biology of female Hypostomus Werneke,D.C., I.W. Armbruster,N. K. Lujan & D. C. luetkeniLac6pdde1803. Ecology of Freshwater Fish, Taphorn. 2005. Hemiancistrusguahiborum, a rrew 5:53-56. suckermouth armored catfish from Southern Ven- Quevedo, R. & R. E. Reis.2002. obscurum: ezuela (Siluriformes: Loricariidae). Neotropical a new species of loricariid catfishe (Siluriformes: Ichthyology, 3: 543-548. Loricariidae) from Southern Brazil, with comments Werneke,D. C., M. H. Sabaj,N. K. Lujan &J. W. Arm- on the genus Pogonopoma.Copeia, 20(J.2:402-41,0. bruster. 2Cf.5.Baryancistrus demantoides and Hemi- Sabaj,M. H., I. W. Armbruster & L. M. Page. 1999. ancistrus suboiridis, two new uniquely colored Spawning in Ancistrus(Siluriformes: Loricariidae) species of catfishes from Venezuela (Siluriformes: with commentson the evolution of snout tentacles Loricariidae).Neotropical lchthyology, 3: 533-542. as a novel reproductive strategy: larval mimicry. Winemiller, K. O. 1989.Patterns of variation in life his- Ichthyological Exploration of Freshwaters,'1,0:217- tory among South American fishes in seasonal 229. environments. Oecologia, 81: 22*241.

Received 30 August 2005 Revised 15 February 2ffi7 Accepted 18 April 2007

Luian et al.: Two new Pseudancistrus