Rhaphiodon vulpinus Agassiz, 1829

TOLEDO-PIZA, MÔNICA, 2000, The Neotropical Fish Subfamily Cynodontinae (Teleostei: Ostariophysi: Characiformes): A Phylogenetic Study and a Revision of Cynodon and Rhaphiodon, American Museum Novitates 3286, pp. 1-1 : 1-

Rhaphiodon vulpinus Agassiz, 1829

Rhaphiodon vulpinus Agassiz, 1829: 76 , pl. 26 (original description, type locality: Brazil). c Evermann and Kendall, 1906: 85 (collection locality unknown, market at Buenos Aires, Argentina). c Fowler , 1906: 467 (description, Peruvian Amazon , specimen not examined). c Eigenmann and Bean , 1907: 667 ( Brazil, lower Amazon ). c Eigenmann and Ogle , 1907: 31 ( Paraguay). c Eigenmann , 1910: 444 (literature compilation). c Bertoni , 1939: 56 ( upper Rio Parana´, identification based on location). c Fowler , 1945: 157, fig. 49 (literature compilation);

–1950: 332 (literature compilation). c Nelson, 1949: 495–523 (morphology). c Schultz, 1950: 49 ( Argentina, Paraguay, Amazon). c Lowe­McConnell, 1964: 110 ( Guyana, Rupununi Riv­ er system). c Ringuelet et al., 1967: 167 (Rio Paraná and Río de la Plata systems, based on location). c Britski, 1972: 82, fig. 4 (literature compilation, fishes from the state of São Paulo, Brazil). c Nielsen, 1974: 45 ( Hydropardus rapax Reinhardt, 1849 placed as a synonym).

c Saul, 1975: 112 ( Ecuador, Río Aguarico, specimen not examined). c Howes, 1976: 205– 229 (myology, functional morphology). c Lesiuk and Lindsey, 1978: 991–997 ( Brazil: Rio Negro, functional morphology). c Géry and Poivre, 1979: 1–4 figs.1–4 (description of juvenile teeth). Mendes dos Santos et al., 1984: 40 ( Brazil, Rio Tocantins; photograph, description). Géry and Mahnert, 1984: 174 ( Ecuador, Río Napo system, specimen not examined). Lauzanne and Loubens, 1985: 56, fig. 52 ( Bolivia, Río Mamore: Trinidad). c Di Persia and Neiff, 1986: 612 (list of species from Río Uruguay system). c Géry, 1986: 66, pl.6a, b (key to cynodontine species). c Ortega and Vari, 1986: 10 (in list of freshwater fishes of Peru). c Ferreira et al., 1988: 344 ( Brazil, Roraima, Rio Mucajaı´, specimen not examined). Goulding et al., 1988: 127 ( Brazil, Rio Negro). c Galvis et al., 1989: 122 ( Colombia, Río Meta system, specimen not examined). Arandas­Rego and Pavanelli 1990: 99 (parasitized by proteocephalids Cestoda, Brazil, at Salobra, Mato Grosso; identification based on location). Barriga, 1991: 30: (in list of freshwater fishes of Ecuador, common name). c Taphorn, 1992: 439 (description, Venezuela, Apure).

Cynodon vulpinus : Cuvier, 1829: 312 (named in a footnote to the description of Hydrocyon ).

c Valenciennes, 1849: 329 ( Brazil; description). c Günther, 1864: 359 (based on Valenciennes, 1849). c Kner, 1859: 47 ( Brazil; description, not able to associate with a specific specimen at NWM). c Peters, 1877: 472 ( Venezuela, Calabozo, specimen not examined). c Steindachner, 1883: 15 ( Peru, Río Huallaga; description).

c Perugia, 1891: 49 (Río Paraguay and Río de La Plata systems, identification based on location). c Boulenger, 1898: 426 ( Brazil, Rio Jurua´). c Goeldi, 1898: 463, 483 (common name, literature compilation). c Pellegrin, 1899: 157 ( Venezuela, Apure); 1909: 150 ( Brazil: Santarém, Rio Negro, Tabatinga). Devincenzi, 1924: 172 (Río Uruguay, Concordia, identification based on location). c Devincenzi and Barattini, 1926: pl.12 ( Uruguay). c Devincenzi and Teague, 1942: 82 (Río Uruguay; diagnosis, identification based on location). c Eigenmann and Kennedy, 1903: 528 ( Paraguay, Río Paraguay, Asunción).

Raphiodon vulpinus (genus name misspelled): Müller and Troschel, 1844: ( Brazil); 1845: 19 (identical to Müller and Troschel, 1844).

c Cope, 1878: 688 (upper Amazon, specimen not examined). c Eigenmann, 1906: 524, pl.11 (photograph of head); 1907: 154 ( Paraguay, identification based on location). Starks, 1913: 20 ( Brazil, Para´; description). c López et al., 1984: 76 ( Uruguay, Río Ururguay, Salto Grande dam, identification based on location). c Godoy, 1987: 192–193 ( Brazil: Santa Catarina, figured).

Hydropardus rapax Reinhardt, 1849: 46–57 (original description; type locality: Uruguay, Montevideo).

Cynodon vupinus : (species name misspelled) Eigenmann and Eigenmann, 1891: 59 (literature compilation).

Rhaphiodon vulpinum : (species name misspelled) Eigenmann and Allen, 1942: 271 ( Peru, Río Pacaya; common name). c Schultz, 1944: 273 (literature compilation);

Rhaphiodontichthys vulpinus : Campos, 1945: 473 ( Brazil: Rio Amazonas; description). c Mago Leccia, 1970: 74 (in list of species from Venezuela). c Cala, 1977: 9 ( Colombia, Río Orinoco system, specimen not examined).

Raphiodontichthys vulpinus (generic name misspelled): Machado­Allison, 1987: 134 ( Venezuela, Llanos, specimen not examined).

DIAGNOSIS: Rhaphiodon vulpinus can be distinguished from all other cynodontines by the placement of the dorsal fin on the posterior third of the body length ( figs. 26 , 28 ) (predorsal distance being 69.3–74.4 versus 52.2–61.1 of SL in all other cynodontines), by its very elongate body relative to its depth (body depth at dorsal­fin origin 12.7–19.6 versus 19.1–33.7 of SL in all other cynodontines), and by a higher number of vertebrae (62–68 versus 44–54 in all other cynodontines). It can be further distinguished from all Hydrolycus species by the insertion of the dorsal fin slightly posterior to the vertical through the anal­fin origin (anterior to that point in Hydrolycus ) and from Cynodon by the lower number of anal­fin rays (38–50 versus 61–80 in Cynodon ).

DESCRIPTION: (table 3) Body very elongate, compressed laterally, greatest body depth at vertical through pectoral­fin origin, depth decreasing posteriorly. Dorsal profile of head slightly concave, ranging from barely concave to straight in specimens smaller than 50 mm SL; degree of concavity varies depending on degree of bending in region posterior to head at time specimen was preserved. Predorsal profile of body straight to slightly concave; slightly posteroventrally slanted at dorsal­fin base, proportionally less slanted from that point to vertical through last anal­fin ray; concave between latter point and origin of dorsalmost procurrent caudal­fin ray. Ventral profile of body convex to pelvic­fin origin, convexity more pronounced anteriorly, less so between vertical through innermost pectoral­fin ray and pelvic­fin origin; straight to anal­fin origin, posterodorsally slanted along anal­fin base, straight to origin of ventralmost procurrent caudal­fin ray. Ventral surface of body with keel from isthmus to anus, interrupted at vertical through pelvic­fin base; keel anteriorly supported by expanded coracoids.

No serrations at margin of opercular bones. Laterosensory canal system in infraorbitals and opercular bones highly branched; canals progressively more pronounced in larger individuals, canals absent in specimens under 50 mm SL.

Mouth obliquely aligned relatively to horizontal axis of body, angle of mouth relative to horizontal plane varying depending on degree of flexure posterior to head at time of specimen preservation. Upper jaw very long relative to head length; posterior tip of maxilla extending slightly beyond vertical through posterior tip of second infraorbital in specimens under 40 mm SL, progressively shorter in larger individuals, not reaching that point in the largest specimens examined.

Second and third infraorbitals not in contact with preopercle posteriorly. Snout short­ er than orbital diameter. Adipose eyelid with notch in region of orbital margin at vertical through middle of second infraorbital.

Teeth in both jaws conical, in single row, varying in size. Teeth in upper jaw partially covered by skin laterally, smaller teeth only with tips apparent. Premaxilla delimited by one canine anteriorly and one canine, slightly smaller, posteriorly; one large conical tooth located between two canines, placed closer to posteriormost canine; several small conical teeth between anterior and posteriormost canines; maxilla with conical teeth of variable size anteriorly, teeth gradually becoming smaller and of more similar size posteriorly. Dentary with one very well developed canine extending through snout when mouth closed, tip of canine reaching nostrils anteriorly; canine larger relative to head length in larger specimens; two conical teeth anterior to largest dentary canine, anteriormost smallest; canine teeth posterior to largest dentary canine varying in size, separated by small conical teeth; teeth gradually decrease in size posteriorly. Specimens under 60 mm SL with row of very small conical teeth internal to main series posteriorly. Teeth on ectopterygoid, mesopterygoid, and metapterygoid small and conical.

Scales without distinct serration. Scales small, larger laterally at level of lateral line. Scales along predorsal midline arranged in somewhat irregular rows. Scales below lateral line obliquely arranged. Lateral­line scales with many divergent branches of the lateral­line canal. Divergent branches more pronounced in larger individuals; lateral­line canal without branches in specimens under 60 mm SL; specimens of 180 mm SL with one ventrally and one dorsally directed branch of lateral­line canal. Lateral­line canal extending to posterior tip of middle caudal­fin rays.

Dorsal­fin rays ii,10. Dorsal­fin origin located on posterior third of body length, slightly posterior to vertical through anal­fin origin. First basal dorsal­fin pterygiophore inserting behind neural spine of 35th (rarely 34th) to 38th vertebrae. Distal margin of dorsal fin slightly convex; diminutive scales on dorsal­fin base, extending one­fifth of distance of fin ray on membrane between fin rays, to lesser extent on remaining rays, scales not as extensive in individuals under 170 mm SL, absent in individuals under 60 mm SL. First basal anal­fin pterygiophore inserting behind hemal spine of 36th (rarely 35th) to 38th vertebrae. Distal margin of anal fin straight. Anal fin covered with scales over half of length of fin rays, more so in larger specimens. No scales covering anal­fin rays in specimens under 60 mm SL. Pectoral­fin rays pointed distally. Posterior tip of longest pectoral­fin ray extending to a point far anterior to vertical through dorsal­fin pelvic­fin origins. Pelvic fin very short. Pelvic­fin rays i,6–7. Pelvic fin pointed distally with first and second branched rays longest. Tips of fin reaching anus. Pelvic­fin base inserted at level of ventral profile of abdomen. Caudal fin almost straight, dorsal lobe slightly convex; caudal fin covered with scales for approximately two­thirds of length of middle rays; degree of coverage decreasing toward dorsal and ventral procurrent rays. Middle caudal­fin ray longest, its tip extending posteriorly to vertical through tip of dorsalmost principal ray, more pronounced in larger individuals, those under 60 mm SL without prominent middle caudal­fin ray.

VERTEBRAE: 62(1); 64(4); 65(7); 66(10); 67(8); 68(1).

COLOR IN ALCOHOL: Specimens retaining guanine on scales with silver coloration on sides of body and head (including lower jaw, except for tip) as far dorsally as horizontal through dorsal margin of orbit. Head and body tan to brownish dorsally, including tip of lower jaw. Specimens under 60 mm SL with silver coloration on abdominal region, remaining portions of body yellowish­tan ground coloration.

Specimens lacking guanine with tan ground coloration on sides of body and head, slightly darker dorsally. Specimens from the Rio Negro have a much darker ground coloration of body and head, with region of head around orbit and opercular region with more conspicuous dark pigmentation. Specimens retaining pigmentation on fins with dorsal fin slightly dusky; dorsal portion of pectoral fin covered with dark chromatophores at its base and outermost fin rays. Caudal fin dusky posteriorly, sometimes with tips of fin­rays dark. Adipose fin hyaline.

GEOGRAPHIC DISTRIBUTION: Main rivers and their tributaries in the Amazon basin from the Río Ucayali system in Peru, eastward to Rio Xingu in Brazil; Rio Tocantins and Rio Capim basins; lower to upper portions of Río Orinoco basin; Rupununi River in the upper Essequibo River system in Guyana; Rio Parana´/ Paraguay, and Uruguay basin, south to Río de la Plata in Argentina ( fig. 27 ).

GEOGRAPHIC VARIATION: The population samples herein identified as Rhaphiodon vulpinus from the Río Orinoco, Rio Amazonas, Río Paraguay­Parana´, and Río Uruguay systems, except for a few specimens detailed below, either agree, or show a very large degree of overlap in all meristic and morphometric characters studied.

Three large specimens ( MZUSP 32808 , 578– 604 mm SL) from the upper portions of the Rio Xingu in Brazil, have a considerably higher number of lateral­line scales (142 in one specimen, 150 in two specimens) and branched anal­fin rays (50 in all three specimens) compared to specimens from the remaining portions of the species range (122– 138 and 38–47 for lateral line scales and branched anal­fin rays respectively), including specimens from the lower portions of the Rio Xingu. Until more specimens from the region become available for study, the cited specimens are tentatively assigned to Rhaphiodon vulpinus .

See above under Color in Alcohol for geographical variation in color patterns.

REMARKS: Rhaphiodon vulpinus was described on the basis of a single specimen collected by Spix and Martius in the rivers from Brazil (‘‘Brasiliae fluviis’’). The type locality of Rhaphiodon vulpinus was not located precisely. Papavero (1971; map following page 66) described the itinerary of the Spix and Martius collecting trip. Rhaphiodon vulpinus occurs in all portions of the Amazon basin where they collected. Within the Rio Paraná system they collected in a few tributaries of the upper Rio Parana´. Some specimens examined in the present study come from the Rio Paraná itself, and lower portions of a few of its tributaries. Therefore, its is possible that the holotype of Rhaphiodon vulpinus originated in the Rio Paraná basin. Kottelat (1988) commented on the status of the Spix and Martius specimens that Agassiz used as the basis for his descriptions and cited the specimen in the collection of the Musée d’Histoire Naturelle, Neuchâtel (MHNN 822) as the potential holotype. That specimen was examined in the present study ( fig. 28 ) and it is herein regarded as the holotype of Rhaphiodon vulpinus Agassiz, 1829 . The proportional depths at the pelvic­ and pectoral­fin origins in this specimen lie slightly outside the range observed for all other specimens used as the basis for the morphometric characterization of this species (table 3). The differences may be preservation artifacts in this very old specimen.

The holotype of Hydropardus rapax Reinhardt, 1849 (ZMC 183), herein placed in the synonymy of Rhaphiodon vulpinus , was also examined ( fig. 29 ). The length of the dentary canine is relatively higher than the maximum value found in the remaining specimens of R. vulpinus in which this feature was measured (19.3 versus 12.1–17.9 of HL for R. vulpinus ). As mentioned in the description above, the dentary canine is larger relative to head length in larger specimens. Since the holotype of Hydropardus rapax is the largest examined specimen herein assigned to Rhaphiodon vulpinus , the higher value for the relative size of the dentary canine observed in the specimen may be a function of its larg­ er size. A few meristic features of Hydropardus rapax also lie outside the range presented by the remaining Rhaphiodon vulpinus specimens (table 3). The holotype of Hydropardus rapax has 121 lateral line scales, 27 scales around the caudal peduncle, and 37 branched anal­fin rays (versus 122–125; 30– 39, and 38—50, respectively, for Rhaphiodon vulpinus ). The holotype of Hydropardus rapax comes from Montevideo, Uruguay. Whether the specimen was actually collected in Montevideo or was shipped from there to Europe may be resolved after translation of the original description published in Danish. As already mentioned above under Geographic Variation, no meristic or morphometric differences were found among the samples examined that conform to any geographical pattern. Specifically, specimens from the Río Parana´/ Paraguay, and Uruguay basins do not show a tendency toward lower values for the meristic features mentioned above for Hydropardus rapax that could suggest that the latter would be distinct from Rhaphiodon vulpinus .

Rhaphiodon is the most widely distributed cynodontine genus in South America and also the least speciose. Hydrolycus and Cynodon do not occur south of the Amazon basin in the Río Parana´/ Paraguay and Río Uruguay basins. Four Hydrolycus species were recognized two of which were previously undescribed. Three Cynodon species were recognized two of which was previously undescribed. Only one species was recognized within Rhaphiodon . Widely distributed characiform species, that occur throughout the major river drainages in South America (i.e., Río Orinoco, Rio Amazonas, Río Parana´/ Paraguay and Río Uruguay basins) are not limited to cynodontines. Other examples include Curimatella dorsalis (Eigenmann and Eigenmann, 1889) , recently revised by Vari

(1992b), and Thoracocharax stellatus (Kner, 1859) , see Weitzman (1960: 220).

MATERIAL EXAMINED: 420 specimens (63, 68.9–623.0):

TYPE MATERIAL: MHNN 822 (1, 303.0) Brazil; holotype of Rhaphiodon vulpinus Agassiz, 1829 . ZMUC 183 (1, 623.0) Montevideo, Uruguay; holotype of Hydropardus rapax Reinhardt, 1851 .

NONTYPE MATERIAL: ARGENTINA. Buenos Aires : AMNH 12251 (3, 163.0–215.0) Buenos Aires, Darsena Norte; BMNH 1881.7.2 :17 (1, 604.0) R. Plate (= Río de la Plata) ; CAS 113493 (1, 455.0) ; USNM 55574 (2, 128.7–184.0) Buenos Aires; NMW 68551 (2) La Plata; Santa Fé : MCZ 828 (1, 252.0) ; NMW 57116 (2) Rosario; USNM 126662 (3, 170.0–181.0) Argentina; BOLIVIA. El Beni : AMNH 77450 (1, 56.8) Río Mamore´, Puerto Siles; AMNH 77507 (1, 168.0) Río Mamore´, ca. 15 km S Limoquije ; MNHN 1989 1466 (1, 293.0) Trinidad, Laguna Capital; BRAZIL. Amazonas: MCZ 21379 (2, 319.0–366.0) Villa Bella, Rio Amazonas at Parintins and environs ; BMNH 1893.4.24 :30–31 (2, 317.0–350.0); MNHN 1909 0122 (1, 265.0) Manaus; USNM 307310 (2, 182.0–197.0) ; USNM 308672 (1, 188.0) ressaca at Ilha da Marchantaria ; USNM 308643 (1, 81.6) near Manaus, Camaleão, Ilha da Marchantaria ; MCZ 79141 (1, 73.3) Lago Jacaretinga, near Manaus; MCZ 21383 2 (365.0–387.0) Paraná do Janauari; MCZ 21373 (1, 321.0) Lago do Iranduba ; BMNH 1897.12.1 :181 (1, 147.4) Rio Jurua´; BMNH 1925.10.28 :121–124 (4, 350.0–379.0) Manacapuru; MZUSP 6537 (14, 215.0–264.0) , MCZ 21402 (4, 35.6– 99.0) Lago Manacapuru; BMNH 1976.11.12 : 201–203 (3, 30.6–47.9); USNM 310941 (2, 202.0–266.0) muddy igarapé connecting Rio Solimões and a blackwater lake ca. 15 km W of Coari ; MZUSP 36093 (2, 291.0–327.0) Lago Pantaleão, mouth of Rio Japura´; MZUSP 36092 (1, 406.0) ressaca do Lago Urini, mouth of Rio Japura´; MZUSP 36101 (1, 470.0) Paraná do Castanho, Lago Amana˜, mouth of Rio Japura´; MZUSP 27339 (1, 296.0) mouth of Rio Japura´, Rio Solimões ; MCZ 21404 (1, 158.0) Rio Iça´, near the Brazilian­Colombian border; MZUSP 23338 (1, 296.0) Rio Solimões , Fonte Boa ; MZUSP 23453 (1, 276.0) Rio Solimões , near Ilha Barurua´, above mouth of Jutaı´ ; MZUSP 23476 (1, 173.0) Rio Solimões, near Ilha Xibeco , above mouth of Jutaı´ ; MZUSP 24936 (2, 228.0–295.0) Rio Solimões , Lago Janauacá and surroundings ; MZUSP 24957 (6, 296.0–342.0) Lago Janauaca´, right margin of Rio Solimões ; MZUSP 26934 (1, 309.0) Lago Janauaca´, Manaus, and surroundings; MNHN 1994 0169 (3, 160.0– 189.0) Rio Solimões ; MZUSP 13498 and 13499 (2, 312.0–354.0) Rio Amazonas , Itacoatiara ; MZUSP 32813 (1, 330.0) Rio Negro, Anavilhanas, Lago do Prato ; MZUSP 6143 (3, 274.0–463.0) Rio Negro , above Manaus ; MZUSP 43317 (1, 394.0) Cantagalo, Rio Negro ; NMW 57092 (2) , NMW 57093 (5) ; NMW 57094 (1) mouth of Rio Negro ; MCZ 21410 (3, 47.6–61.2) Rio Negro, Lago do Aleixo ; MZUSP 37873 (1, 182.0) Igarapé Beem, Humaita´; MZUSP 6970 (1, 216.0) Rio Madeira , 25 km below Nova Olinda ; MNHN 1909 0194 (1, 173.0) Tabatinga; MZUSP 23484 (2, 228.0–266.0) , Lago do Prego , in front of Santo Antônio do Iça´ ; MZUSP 23518 (1, 280.0) Santo Antônio do Iça´, mouth of Rio Iça´; MCZ 21390 (3, 259.9–310.0) Rio Javari at the Peruvian­Brazilian border ; MZUSP 24606 (1, 209.0) mouth of Rio Pacia´; MZUSP 6319 (1, 215.0) Lago Castro, mouth of Rio Purus ; MZUSP 6380 (2, 328.0–356.0) Rio Purus , Lago Beruri ; NMW 57115 (1) Rio Purus ; MCZ 21376 (1, 310.0) Rio Solimões at Tefé and environs ; MZUSP 6097 (5, 300.0–389.0) Lago Puraquequara, Rio Puraquequara system ; MZUSP 7527 (1, 265.0) Paraná de Urucara´; Pará: CAS 71050 (2, 182.0–232.0) , CAS 79265 (1, 391.0) Rio Santarém ; MZUSP 23897 (1, 279.0) Rio Capim , near Badajós ; MZUSP 23932 (6, 285.0–346.0) Rio Capim , Vila Santana ; CAS 71051 (1, 221.0 mm SL) Rio Tapajós (into Rio Amazonas ) at Santarém ; CAS 79268 (1, 371.0) market at Santarém; MNHN 1909 0075 (1, 176.0) Santarém; MZUSP 24237 (3, 324.0– 363.0) Rio Tapajós, Ilha Tapiúna ; MZUSP 24247 (1, 363.0) Rio Tapajós , Aveiro ; MZUSP 24314 (1, 384.0) Rio Tapajós, lake at Ilha do Campinho ; MZUSP 24330 (3, 319.0–410.0) Rio Tapajós , Barreirinha ; MZUSP 32819 (12, 306.0–393.0) Rio Tapajós , between Itaituba and São Luı´s ; MZUSP 25299 ( 1, 444.0 right margin of Rio Tapajós , in front of National Park headquarters ; MZUSP 25560 (1, 418.0) São Raimundo, left margin of Rio Tapajós , ca. km 51 of highway BR 230 ; MZUSP 25567 (1, 370.0) left margin of Rio Tapajós , between National Park headquarters (km 67) and Ramal Santa (km 64) ; MZUSP 5628 (4, 308.0–351.0) Lago Paru, Oriximina´; MZUSP 5677 (1, 321.0) Rio Trombetas , mouth of Lago Paru ; MZUSP 5414 (2, 252.0–256.0) ; MZUSP 8258 (1, 247.0) Rio Trombetas , Oriximina´ ; MZUSP 9429 (1, 332.0) mouth of Cumina´– Miri, near Oriximina´; MZUSP 32810 (8, 258.0–354.0) Rio Trombetas , Cumina´ ; MZUSP 32811 (17, 267.0–393.0) Rio Trombetas , 20 km above mouth ; MZUSP 15769 (1, 442.0) Rio Trombetas, igapó at Lago do Farias, Reserva Biológica de Trombetas ; MCZ 21384 (1, 300.0) , MCZ 21385 (1, 300.0) Rio Tocantins, Cameta´; MZUSP 24077 (6, 169.0–203.0) Rio Tocantins, lake at the margins of Igarapé Espírito Santo between Baião and Tucuruı´; MZUSP 24175 (2, 229.0–231.0) Rio Tocantins, Laguinho, near Tucuruı´; MCZ 821 (1, 358.0) , MCZ 21399– 21400 (3, 269.0–293.0) Belém and environs; MZUSP 24014 (2, 255.0–336.0) Paraná Samaúma, mouth of Rio Tocantins; MZUSP 32820 (1, 327.0) Rio Itacaiúnas , Serra dos Carajás, Igarapé guas Claras ; MZUSP 32821 (14, 281.0–396.0) Rio Itacaiúnas , Caldeirão ; AMNH 3937 (2, 274.0–282.0) , CAS 122083 (4, 266.0–285.0) , NMW 57103 (1) , NMW 57104 (3, 259.0–294.0 mm SL) , NMW 57105 (5) Para´; MZUSP 3550 (3, 313.0– 328.0) , CAS 79267 (1, 320.0) Belém; UMMZ 203388 (2, 240.0–263.0) market in Belém; CAS 158801 (1, 46.6) Lago Grande, into Rio Amazonas ; MZUSP 23987 (5, 238.0–280.0) Igarapé Sororoca, Furo de Panaquera ; MZUSP 24005 (1, 282.0) Igarapé Coelho; MZUSP 31501 (1, 299.0) , MZUSP 32809 (40, 285.0–437.0) Rio Xingu , Belo Monte ; MCZ 21397 (2, 432.0–435.0) Rio Xingu , cascade region; Roraima : MZUSP 32816 (1, 415.0) Rio Branco , Marara´ ; MZUSP 32817 (1, 363.0) Rio Branco, between its mouth and Rio Xeriuni ; MZUSP 32818 (2, 361.0–366.0) Rio Branco, Cachoeira do Bem­Querer ; Maranhão : CAS 149264 (1) Lagem Marsal Brook, into Rio Tocantins at Carolina; CAS 71047 (1, 73.7) , MA, represa (= dammed up) Lagem Marsal brook into Rio Tocantins; Goiá s: MZUSP 40672 (4, 347.0–425.0) ; MZUSP 40864 (6, 342.0–405.0 mm SL) Rio Parana ˜, above mouth of Rio Bezerra , Monte Alegre de Goiás ; MZUSP 40775 (1, 370.0) Rio Parana ˜, below mouth of Rio São Domingos, Nova Roma ; MZUSP 40898 (2, 332.0–375.0) Rio Parana ˜, above mouth of Rio São Domingos, Fazenda Barra, São Domingos; Rondônia : MZUSP 32806 (4, 329.0–378.0) ; MZUSP 32807 (9, 196.0–403.0) Rio Madeira , Calama ; MZUSP 32812 (2, 194.0–363.0) Rio Madeira, Cachoeira do Teotônio ; MZUSP 13897 and 13898 (2, 302.0–358.0) Rio Machado, Lago do Paraíso ; Mato Grosso do Sul : MZUSP 43923 (1, 341.0) Rio Parana´, Rio Samambaia , municipality of Taquarucu ; MZUSP 22622 (7, 295.0–332.0) ; MZUSP 22515 (13, 284.0–350.0) Rio Parana´, in front of Jupia´; Mato Grosso: MZUSP 22812 (1, 171.0) Rio Araguaia , Santa Terezinha ; MZUSP 32808 (3, 597.0–600.0) Rio Xingu, confluence Rios Culuene and Sete de Setembro ; São Paulo : MZUSP 23201 (2, 152.0– 225.0) left margin of Rio Parana´, Jupiá dam; MZUSP 24386 (1, 446.0) Rio Tieteˆ, Penápolis; Paraná: MZUSP 13225–13226 (2) Rio Parana´, Porto Mendes; MZUSP 13227– 13231 (5) ; MZUSP 14699–14703 (5) PR, Rio Parana´, Porto Verde; MZUSP 21631 (1, 417.0) Rio Parana´, Guaíra, above Sete Quedas; MZUSP 43389 (1, 351.0) Rio Parana´, Itaipu Dam, Município of Foz do Iguaçu ; MZUSP 43917 (1, 342.0) , MZUSP 43918 (3, 382.0–401.0) Rio Parana´, Município of Porto Rico ; MZUSP 3121 (3, 242.0–326.0) Amazonas and Para´; MNHN 4493 (1) Brazil; MNHN 1909 0318 (1, 252.0) Brazil; CAS 71052 (1, 248.0) South America ; CAS 78305 (1, 148.0) aquarium specimen (died at the Steinhart Aquarium, San Francisco). ECUADOR. Napo : FMNH 103392 (1, 299.0) outflow of Laguna Jatuncocha; FMNH 104997 (2, 420.0) Río Payamino , 14.1 km upstream from mouth in Rio Napo ; FMNH 104998 (1, 332.0) Rio Tiputini , near mouth in Rio Napo ; MCZ 52354 (1, 318.0) Río Payamino and small tributary ca. 5–6 km upriver from the mouth, into Río Coca ; GUYANA . BMNH 1972.7.27 : 51 (1, 401.0) Rupununi River ; CAS 16071 * (mixed lot) (6) , Guyana, Menari Ranch, near Lathan (Lethem?), border with Brazil. PARAGUAY. BMNH 1935 ­ 6.4 : 34–39 (6, 80.0–264.0) W Asunción; BMNH 1935 ­ 6.4 :40 (1, 68.9) Asunción bay; CAS 18238 (1, 183.0 mm SL) , Río Paraguay, Asunción; USNM 181596 (1, 134.3) Río Paraguay, Asunción Bay, near Asunción; UMMZ 208059 (1, 460.0) , Pettirossi fish market (= Mercado Quatro) in Asunción (from ‘‘San Antonio’’); UMMZ 216640 (1, 196.0) Río Paraguay, Villeta between ‘‘el muelle y la barreria’’; NMW 57117 (1) ; USNM 55667 (1) Paraguay. URUGUAY . NMW 57114 (2) Uruguay. VENEZUELA. Delta Amacuro : CAS 50806 (1, 175.0) Río Orinoco , between Puerto Ordez and Ciudad Bolivar ; USNM 222870 (1) Río Orinoco, first small caño on W side of Caño Paloma , 100 m above its mouth, 92 nautical miles upstream sea buoy ; USNM 222871 (10, 246.0–279.0) , USNM 233619 (1, 253.0) , USNM 233930 (1, 340.0) Río Orinoco , inlet near Punta Cabrian, 150 nautical miles upstream from sea buoy ; USNM 222880 (1, 265.0) Río Orinoco , N shore near San Felix, 176 nautical miles upstream from sea buoy ; UMMZ 211306 (2, 145.0–249.0) lagoon of Río Orinoco , 201 nautical miles from sea buoy Amazonas : FMNH 103650 (1, 434.0) pool behind beach of Río Ventuari on S side of river ca. 5 hr. (ca. 12 km) above mouth in Río Orinoco Laguna Pavon ; FMNH 103651 (1, 384.0) Rio Ventuari at beach and small backwater ca. 5 hr. above mouth ; ANSP 161180 (1, 345.0) caño crossing Puerto Ayacucho­El Burro hwy. Apure: ANSP 165773 (1, 380.0) Río Capanaparo, backwater lagoon (mouth of Caño Las Varitas) near San Fernado de Apure­Puerto Haez hwy; Monagas : AMNH 47956 (1, 176.0) shore of Río Orinoco, Buoy 142 nautical miles downstream from Barrancas , north side Isla Varader inlet ; USNM 222863 (1, 227.0) Río Orinoco , small caño near mouth of Caño Guarguapo, 146 nautical miles upstream from sea buoy ; MNHN 1898 0024 (1, 256.0) Venezuela; PERU. Loreto : CAS 134788 (1, 76.5) Río Ampiyacu ; CAS 134789 (1, 130.0) Río Ampiyacu , near Pebas ; CAS 15726 (2, 207.0– 282.0) ; CAS 15727 (1, 264.0) Río Pacaya , at the mouth, Bretana ; CAS 79270 (2, 263.0– 273.0) Río Pacaya (upstream) small, sluggish, brown lowland river, arising in lomas of Eastern Cordillera ; into Río Ucayali at Bretana , MZUSP 15219 (3, 101.0–125.0) Caño Moema, Rı´o Amazonas; MZUSP 26447 (1, 32.0) Supaycocha, Jenaro Herrera; CAS 79266 (1, 410.0) Lago Cashiboya, a cutoff of Río Ucayali (connected to river by a channel), above Contamana; MZUSP 26729 (1, 210.0) Río Ucayali, Pucallpa; USNM 280454 (1, 297.0) main channel and side pools of Río Ucayali, approximately 10 km upstream of Pucallpa; Amazonas: UMMZ 216909 (1, 287.0) Amazonas.

Figures

Fig. 4. Anterior and orbital regions of neurocranium of Hydrolycus scomberoides, MZUSP 32093; left side, lateral view, anterior to left.

Fig. 1. Map of South America showing geographic distribution of the Cynodontinae; recent species

Fig. 2. Infraorbital series, supraorbital and antorbital of (A) Hydrolycus armatus, MZUSP 32607; and (B) Hydrolycus wallacei, MZUSP 32638; left side, lateral view, anterior to left. Arrow points to fifth infraorbital.

Fig. 3. Antorbital of (A) Hydrolycus tatauaia MZUSP 32630, and (B) Cynodon gibbus MZUSP 32587, left side, medial view, anterior to right.

Fig. 26. Rhaphiodon vulpinus, MZUSP 32809, 305 mm SL, Brazil, Para´, Rio Xingu, Belo Monte.

Fig. 28. Rhaphiodon vulpinus, holotype, MHNN 822, 303 mm SL, Brazil.

Fig. 27. Map of South America showing geographic distribution of Rhaphiodon vulpinus (type locality inexact = ‘‘Brasiliae fluviis’’ [= rivers of Brazil]. Some symbols represent more than one lot of specimens or locality.

Fig. 29. Rhaphiodon vulpinus, holotype of Hydropardus rapax, ZMC 183, 623 mm SL, Uruguay, Montevideo.