25 1

1 Ichthyol. Explor. Frcshwatcrs, Vol. 4, No. 3, pp, 251-260.6 figs,, 2 tabs., November 1993 O 1993 by Vcrlag Dr. Fricdrich Pfcil, Münchcn, FRG - ISSN 0936-9902

Two new species of Aguamnichthys from the Amazon basin (Siluroidei: )

Jansen A. S. Zuanon *, Lúcia H. Rapp Py-Daniel * and Michel Jégu **

Two new species of A~iinriiriiclifliysare described and compared with A, torosrts. Agimrrrriicli!/i!ys tomitiriserisis, new species, from the Tocantins River, differs from A. tornsirs by having a larger orbital diameter, overlapping branchiostegal membranes, distance between snout tip and anterior nostrils less than distance between anterior and posterior nostrils, and distance bctwccn snout tip and posterior nostrils less than distancc bctwcrn postcrior nostrils m~clposterior cdgc of orhit8ilrini, A,~tf~i~tftril./it//!/.~i/tpii, ncw speciris, Iron1 thc Solim(kv Itivor, ciifftys from thc othor two species by having a broader liead, smaller eyes and a widcr mouth.

Introduction Material and methods

A~i~nrirniclrfh!yst~i~osirs lias been described by Measurements and counts follow Stewart (1986). Stewart (1986) based on a single specimen from Institutional abbreviations: INPA, Instituto Na- tlie Peruvian Amazon; it is distinguishable from cional de Pesquisas da Amazônia, Manaus; other pimelodid genera by the unus'ual shape of LACM, Los Angeles County Museum, Los An- the air bladder, which lias finger-like projec- geles; MNHN, Muséum National d'Histoire tions on its posterolateral margin and anterior Naturelle, Paris; MZUSP, Museu de Zoologia tubular extensions, and by a subterminal mouth da Universidade deSão Paulo, São Paulo. Other with broad premaxillaries ending in posterola- abbreviations: HL, head length; SL, standard teral extensions. length. The description of colouration is based Reccnt I y, col Icc t inns madc i ti t hc Sol i mdes on both fresh and preserved specimens of Itivcr, Marchantaria Island, and on the rocky A. tocnritiriserisis and on tlie preserved holotype bottoni of the Tocantins River (Fig. 1) resulted of A. irrpni. in the discovery of specimens of A~iinrriiiiclithys * which turned out to represent two undescribed species.

* SCT/lnstituto Nacional de Pesquisas da Amazônia, Caixa Postal 478, CEP 69011 Manaus, Amazonas, Brazil * * Convênio ORSTOM/CNPq/lnstituto Nacional de Pesquisas da Amazônia, Caixa Postal 478, CEP 69011 Manaus, Amazonas, Brazil.

Ichthyol, Explor. Freshwaters, Vol. 4, No, 3

't I I I I I O0 70 60 50 40

Fig. 1. Type localities of ASimrirtiiclitltys torosiis (circle), A. itipni (triangle) and A. focntititisettsis (squares).

Key to the species of Agunrunichthys Aguarunichthys tocantinsensis, new specie! (Fig. 2a) 1, - Head and body robust, stout (head width 84.9 % HL, 24.0 % SL); mouth width 55.5 % Holotype. INPA 5400,301 mm SL; Brazil: Pai HL; eye small (orbital diameter 6.3 % HL, State: Tocantins River drainage, rapids abm 1.8 % SL); cream coloured with faint small Marabá; M. Jégu, 21 November 1990. dark spots on head and body (Solimões River). .Paratypes. BRAZIL: PARA STATE: INPA 539 ...... A, iiipni 3, 211-317" SL; Tocantins River drainag - Head and body elongate (head width below the Tucurui dam, rotenone; M. Jégu,Sel 66-70 % HL, 18-21 % SL); mouth width tember 1984. - INPA 5401, 3, 240-295 mm SI 37-45 % HL; head and body olive-brown Tocantins River drainage, rocky ponds belos with large darker spots. the Tucurui dam, just after closing the dan n ...... *.,L G.M. dos Santos, November 1984. - MZUS uncat., 1,282 mm SL, MNHN uncat., 1,211 mi 2. - Interdorsal distance (distance between dor- SL; Tocantins River drainage, below the Tua sal and adipose fin) 10.0-12.6 % SL; eye rui dam, rotenone; M. Jégu, September 1984. large (orbital diameter 11.6-14.6 % HL; 3.2-4.0 % SL) (Tocantins River). Diagnosis. Agunnrnichtlrys tocnntiizseizsis is di! ...... A. tocnntinsensis tinguished from the other species of the gem - Body more elongate (interdorsal distance by presenting a larger orbital diamett 9-5% SL); eye small (orbital diameter 8.2 % (3.2-4.0 % SL, vs. 2.1 % SL in A. torosiis an HL; 2.1 % SL) (Cenepa River). 1.8 % SL in A. inpni), a smaller interdorsal di! ...... A. torosus tance (10.0-12.6 % SL, vs. 9.5 % in A. torosirs an

Zuanon et al.: Two new Agimnrriiclttk, 253

5 I. . "' .., . .. ., i'..'.'

Fig. 2. a, AgiinriwicMhys tocnufirisemis, páratype, INPA 5399,317 mm SL; b, A. iripni, holotype, INPA 5398,420 mm SL (rightside, reversed).

7.1 % in A. i?ipi),and a smaller internares dis- tions of cephalic lateral line system run along tance (4.3-4.9YO SL, vs. 5.1 % SL in A. tor'osirs supraoccipital process, almost parallel to it. Eye and 5,5 % SL in A. i11p7i). large, in a latero-superior position. Anterior nostril closer to snout than to posterior nostril Description. Morphometric and meristic data and at the same level of insertion of maxillary are presented in Tables 1 and 2. Ventral profile . Posterior nostril, anteriorly surrounded of body almost straight; dorsal profile strongly by dermal flap, closer to tip of snout than to ascending from tip of snout to origin, posterior edge of orbital rim. Supraoccipital i- horizontal till anterior third of adipose fin, and process long and narrow, in contact with pre- IS then, gradually descending till end of caudal dorsal plate. Only one detectable fontanelle, long, 'r peduncle. Head longer than wide, weakly de- extending from just behind posterior nostrils to d pressed, Cephalic lateral line system well devel- about posterior edge of orbit. Mouth distinctly I- oped, although more conspicuously seen on subterminal, with mouth opening slightly d snout and on infraorbital region. Some projec- arched. Maxillary barbel reaching posteriorly to

Ichthyol. Explor. Freshwaters, Vol. 4, No. 3 t I 4

Fig. 3. Ventral view of left half of air-bladder of: a, Agunrrrnz'chthys tocnutitisemis, INPA 5399, 280 mm SL; b, Ahpi, holotype, INPA 5398, 420 mm SL, Scale bars: 5". approximately second third of adipose fin. In er than simple ones. Adipose base long and not smallest specimens (below 245 mm SL), maxil- connected to dorsal. Adipose fin higher at antc- lary barbcl can reach beyond adipose fin, Outer rior third, Forked caudal fin, with dorsal lobc mental barbel reaching middle of pectoral spine; slightly longer and more pointcd than ventral inner nicntal barbel generally cxtcnding to pec- lobe. Caudal fin with 17 procurrent rays dorsal- toral origin, Branchiostegal membranes over- ly and ventrally. Total vertebrae countings 43-44 lapping at midline, Gill rakers, on first left plus one for the PU1 centra, branchial arch: ventral limb with 1-3 rudimen- tary rakers and 10-11 normal rakers; dorsal limb Coloration, Live specimen: head, body and with 4-5 rakers; total 15-18. fins brownish green with black spots. Barbels Air-bladder as in A. forosirs (Fig. 3a) black. Predorsal plate triangular, extending poste- Preserved specimens: dorsal surface light riorly on both sides of dorsal spine. First ray of brown, with darker brown, rounded spots. dorsal fin present, weakly developed, but with- Flanks spotted, the largest spots being on the out locking mechanism. Posterior margin of middle portion of the sides; their size decreases dorsal fin straight to slightly concave. Dorsal anteriorly and posteriorly, All spots are smaller spine flexible, not pungent, without serrations, than eye diameter. Ventral surface cream col- and about as long as first branched ray. When oured, without spots, but with melanophores depressed, tip of dorsal rays reaches beginning dispersed around mouth and on infraorbital of adipose keel. Posterior margin of pectoral region. Small blotches around anal fin base, concave, its tip not pointed. Pectoral spine flat- more numerous on ventral surfacc of caudal tened dorso-vcntraliy, flexible, with about 65 peduncle. Maxillary barbel brown dorsally and wcnk scrrnc on posterior margin, largcr and beige ventrally; nicntal bnrbcls cream coloured more densely concentrated on proximal half. with few melanophores on the base, more con- Pectoral spine as long as first branched ray. spicuous on outer ones. Whole surface of fins Pectoral fin, when depressed, not reaching pel- brown with small dark spots. Posterior portion vic origin. Posterior margin of pelvic fin straight, of caudal fin lighter and less conspicuously spot- with simple ray slightly longer than first ted. Both pectoral and pelvic fins more conspic- branched ray. Posterior margin of anal conspic- uously spotted dorsally than ventrally. uously concave, with branched rays much long-

Zuanon et al.: Two new Aguantniclilhys 255

Etymology. Named tocmtin~ensisafter the riv- Most of the specimens were collected about 15 er where the type series has been collected. days after closing the Tucurui dam, in the To- cantins River, when the riverbed was almost Discussion. Direct comparison between simi- exposed. Intensive studies and collections were lar size specimens of A. torosits (346 mm SL) done 5 years before the closing of the dam but and A. tocniifiriserisis (317 mm SL) shows a clear A, tocmitinsensis was not found at that time. differenciation. Ag~inrirnichtliystocnriHn8ensis has Even local fishermen were not familiar with this a larger eye (orbital diameter 11.6 % HL, vs. species. The discovery of fish species in the Rio 8.2 % in A. torosrrs), a smaller interorbital dis- Tocantins which had not been caught before the tance (25.4 Ir HL, vs, 29.1 %), a stouter body closing of the dam, as Pnrnncistrirs nrrmrrtincirs (head length 27.3 % SL, vs, 25.2 %), a greater (Rapp Py-Daniel, 19881, Snrtor. hrcrrrrriertsc (San- predorsal distance (37.5 '30 SL, vs. 34.7 %), more tos & Jégu, 1987), Teleocichln cirrdcrdln (Kullan- gill rakers (15-18, vs. 13-14), and more densely der, 1988), Creriiciclrln spp. (Ploeg,1986) gives us spotted body (Figs. 4-51, new insights in the fish fauna of the rapids, a Agimrrtniclith!ys tocnrrtiriserisis was collected biotope strongly endangered by the construc- in areas with strong currents and rocky bottom. tion of hydroeletric dams.

Table 1. Morphotnetric ratios of Agiinrirrticlifli!ys torasits (n=l), A. tocnriti~~serisis(n=9) and A, ~'tipni(n=l). Data in square brackets are for holotype.

character A. lorostrs A. tacnrilirisrrisis A. itl/Jlli

~~ ~ standard length (mm) 346 211-317 13011 420 percentage of standard length ' head length 25.2 26.5-28.2 127.61 28.3 body depth 17.6 17.3-22.5 [22.51 23.3 predorsal length 34.7 35.7-37.7 137.71 36.0 prepelvic length 47.4 42.4-50.7 149.51 49.0 preanal length 70.2 68-3-72,] 168.81 70.0 interdorsal distance 9.5 10.0-12.6 i11.31 7.1 I dorsal spine length 20.3 19.6-22.5 l20.71 22.6 pectoral spine length 21.4 20.2-23.6 [21.41 22.6 3 1st ventral ray length 16.6 16.0-18.2 [17.21 17.1 ist anal ray length 16.8 14.8-16.8 [16.81 16.2 t anal base length 11.7 10.4-12.7 [11.8] 12.6 adipose base length 35.8 32.4-35.7 t35.71 33.3 ? caudal length (upper lobe) , 23.7 19.9-29.8 119.91 26.9 S caudal peduncle length 18.8 18.2-20.6 [19.4] 20.6 r caudal peduncle depth 8.2 ' 8.0- 9.6 [ 9.61 9.5 head width 18.4 18.1-21.6 121.11 24.0 Iiend depth 14.1 13.2-16.1 115.5) 16.7 :IS snout Icngtl1 13.6 14.0-15.3 Il 5.31 15.5 orbital diameter 2.1 3.2- 4.0 1 3.51 1.8 i interorbital distance 7.3 6.2- 7.5 I 7.51 7.9 1 internares distance 5.1 4.3- 4.9 [ 4.81 5.5 i bucal width 9.8 10.1-12.1 110.61 15.7 1 percentage of head length . head width 72.3 66.7-77.6 [76.5] 84.9 1 head depth 55.8 48.6-58.2 [56.01 58.8 I orbital diameter 8.2 11.6-14.6 [12.8] 6.3 interorbital distance 29.1 22.9-27.2 [27.2] 27.7 snout length 53.8 52.1-55.4 [55.41 54.6 bucal width 38.9 37.3-45.3 i38.61 55.5 premaxilar width 32-3 32.7-35.8 133.01 37.8

Ichthyol. Explor. Freshwaters, Vol. 4, No.3 Fig, 4. Head of A~rmxriicliflrysfocnufirismis, INPA 5401-1, 295 min SL)

' Zuanon et al.: Two new Agimnoiichlhys 257

I

Fig. 5. Head of Ayimrtrriichfliys forostis, holotype, LACM 39651, 346 mm SL.

Ichthyol. Explor. Freshwatcrs, Vol. 4, No, 3

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258

Aguarunichthis inpai, new species nostril and posterior edge of orbital rim. Fonta- (Fig. 2b) nelle narrow and elongate anteriorly, beginning close to level of posterior nostril and extending Holotype. INPA 5398, 420 nini SI.; Brazil: Am- to lcvcl of posterior margin of orbital rim. Supra- wonas State: Solinicies liivcr drainage, north of occipital proccss long and narrow, in contact tlic Marchantaria Island, at about 15 km above with yredorsal plate. Mouth distinctly subtcr- confluence with Rio Negro drainage, bottom minal, with upper lip well developed. Premax- trotline; J. Zuanon, 27 September 1988. illary tooth plate broad and slightly arched, with lateral projections backwards, and partially ex- Diagnosis. A,g~r~ri~riiclithysinpi is distinguished posed when mouth is closed. Dentary tooth from the other two species by having a smaller plate narrower than premaxilla, enlarged on eye (orbital dianieter 6.3 % HL, vs, 11.6-14.6 % midline and pointed on the tips, which are di- HL in A, /ocnnfiiiserisis and 8.2 % HL in A. toro- rected postero-laterally, Maxillary barbel extend- sus), a broader and more depressed head (head ing to about 75 % of adipose-fin base length. width 84.9 % HL, vs. 66.7-77.6 % HL in A. tocm- Outer mental barbel extending to half of pecto- tinserisis and 72.3 % HL in A. torosus; head depth ral spine length. Inner mental barbel extending 58.8 % HL, vs, 48.6-58.2 % HL in A. focnntinsen- to insertion of pectoral fin. Branchiostegal mem- sis and 55.8 YO HL in A. torosirs), a wider mouth branes slightly overlapping at midline. Gill rak- (mouth width 55-5 76 HL, VS. 32.7-35,8 % HL in ers hard, with following disposition on first left A. tocnrifirrscrisis and 323 % HL in A. for"ï, gill arch: ventral limb with 1 rudimentary raker and a fainter spotted color pattern. and 10 developed rakers, and dorsal limb with 4 rakers; total 15. Description. Morphometric and meristic data Air-bladder as in A. torosirs (Fig, 3b). are presented in Tables 1 and 2. Predorsal plate triangular, extending poste- Specimen robust, stout, with dorsal profile riorly on both sides of dorsal spine. First dorsal- slightly ascending from tip of snout to origin of fin ray present, but without locking mechanism. dorsal fin and then descending towards caudal Posterior margin of dorsal fin slightly concave. peduncle. Head broad and depressed. Cephalic Dorsal spine with distal third flexible, little long- lateral line system well developed, with strong er than first branched ray. Dorsal spine without radiation on infraorbital region. Some projec- serrae. Posterior margin of pectoral fin concave. tions of the cephalic lateral line system run par- Pectoral spine flattened dorso-ventrally, with allel to supraoccipital process. Eye small, in distal half flexible and as long as first branched . supero-lateral position. Interorbital region al- ray. Anterior margin of pectoral spine smooth; most plain. Snout broad. Anterior nostril tubu- posterior margin with about 100 weak and not lar, directed forward and situated at the same pointed serrations (left side). Simple pelvic ray level as maxillary barbel. Distance from anterior hard on base and one-third smaller than first nostril to tip of snout approximately as long as branched ray, Simple anal ray smaller than first distance between anterior and posterior nostril. branched ray (last two anal rays united at tlic Posterior nostril with anterior semicircular flap base and counted as one). Adipose base long of skin. Distance from posterior nostril to tip of and not connected to dorsal. Adipose fin higher snout longer than distance between posterior at anterior third. Forked caudal fin, with dorsal

Table 2. Meristic data of ASirn,rrriiclrlh!/s /rirosris (n=l),A. focnri/iriserisis (n=9) and A. itipni (n=l). Data in squarc brackets are for holotype.

character A. torvsrrs A. rocnr~tiris~~risis A. iiilwi

dorsal rays 1+6 1+6 [1+6] 1+6 pectoral rays 1+13 1+13 [I+13] 1+13 ventral rays i+5 i+5 [i+5] i+5 anal rays v+9 ~+7-9[~+8] v+9 caudal rays i+8/7+i i+8/7+i [i+8/7+i] i+8/7+i

gill rakers (Ist left arch) 1 14 15-18 [161 15 259 "If i 260

1 lobe slightly longer and more pointed than ven- have provided them with a greater capability to tral lobe. Caudal fin with 17 procurrent rays survive in deep water. dorsally and ventrally, Comparison material. Agimrirtiicklhys torosirs. Coloration. Preserved specimens: body cream LACM 39651-1,346 mm SL, holotype; Peru: De- coloured, with several round brown spots, scat- partamento Amazonas: Rio Cenepa, l .6 km west tered on dorsal surface of head, predorsal re- of Huampami and near to the Peruvian military gion, base of dorsal fin and lateral surfaces of camp Chavez Valdivia, about 210 m asl, approx. body. Largest spots equal to orbit diameter. 4'28's 78"lO'W; R. McDiarmid, 26 VI1 1977, Broad transversal unpigmented stripe at dorsal origin level. Base of flanks and ventral surface unpigmented. Dorsal fin yellowish white with Acknowlegdments small dark spots on the spine and on distal extremity of branched rays. Pectoral fin brown- Field work in Tocantins River drainage was ish grey dorsally, with small dark spots, and funded by INPA/ELETRONORTE Convention ventrally, yellowish white with hyaline stripe and by INPA/ORSTOM Convention. Field work on posterior margin, Pelvic beige, with distal in the Solimões River, Marchantaria Island, was extremity of the rays darker, forming greyish funded by INPA/Max-Planck Convention. We stripe. Anal white, with first branched ray slight- would like to thank J. Seìgel, LACM, for the ly greyish distally. Adipose whitish, showing loan of the holotype of A. torostrs and Labbish narrow stripe on outer margin. Anteriorly, dor- Chao for hand-carrying it. We are most grateful sal surface of adipose fin covered by diffuse to Vernon Thatcher, INPA, for his endless pa- inconspicuous small dark spots. Caudal unpig- tience in revising our English manuscript, mented, whitish.

Etymology. irtpoi, latinization of the acronym Literature cited INPA (Instituto Nacional de Pesquisas da Amazônia). Jégu, M. & G. M,dos Santos. 1988. Une nouvelle espPce du genreMylesiriris (Pisces,Serrasalmidae), M. pnrrci- Discussion, Despite existing connections be- sqirnrnntirs décrite du bassin du RioTocantins (Ama- tween the Solimdes-Amazonas River and the zonie, Brésil). Cybium, 12: 331-341. Tocantins River, the differences found between Kullander, S. O. 1988. Tekocichlu. a new of South American rheophilic cichlid fishes with six new A. iiipi and A. tocniifiiiseiisisare evident enough species (Teleostei: Cichlidae). Copeia, 1988 196-230. to consider them as two different taxa. Besides, Ploeg, A. 1986. The cichlid genus Creriiciclrln from the A. tocnrrtirtsmisis was collected above rapids in Tocantins River, State of Partí, Brazil, with descrip- the Rio Tocantins, a biotope charactcrized by a tions of four new species (Pisces, I'erciformes, Cich- group of rheophilic species' (Mylesiiiirs pnirci- lidae). Beaufortia, 36: 57-80. sqtrnmnlirs, Jégu & Santos, 1988; Hnrftk spp., Rapp l'y-Daniel, L. H. 1989. Redescription of Pnrnricis- Rapp l'y-Daniel et.al., in prep.) and greatly dif- trus nuruntincus (Castelnau, 1855) and a preliminar fering from the habitat of A. iripni, Agirnrirn- description of two new genera: Bnr!/nricistrirs n.6. and Olipvicistriis n.g. (Siluroidei; Loricariidae). ichtliys iripai was collected at a depth of about 30 Cybium, 13: 235-246. meters (dry season) in the Solimcies River Santos, G. M. & M. Jé&. 1987, Novas ocorrências de ("várzea" area); there, the riverbed consists of Giinthodolirs bideris, Syrinptolnemirs cirigirlntirs e de- sediments. scriçäo de duas espécies novas de Snrtor (Characi- Marchantaria Island, the type locality of formes, Anostomidae). Amazoniana, 1kl81-196. A. iizpni, is an area very close to Manaus that is Stewart, D.J. 1986. Revision of Piinelodirin and descrip- overfished by local fishermen. Despite this fact, tion of a new genus and species from the Peruvian fishermen were not used to catch A. iripni (the Amazon (Pisces: Pimelodidae). Copeia, 1986: 653-672. same as with A. focniitiiiserisis and A. torosirs). It may be the deep-bottom dwelling habits of these fishes that explain the rarity of their capture. It Received 9 June 1992 can be speculated that the amazing shape of the Revised 27 August 1993 air-bladder of the Aguarunichthys species may Accepted 12 October 1993

Zuanon et al,: Two new Agunnoiiclithys