Cetopsis plumbea Steindachner, 1882

Vari, Richard P., Ferraris Jr, Carl J. & de Pinna, Mário C. C., 2005, The Neotropical whale catfishes (Siluriformes: Cetopsidae: Cetopsinae), a revisionary study, Neotropical Ichthyology 3 (2), pp. 127-238 : 191-194

Cetopsis plumbea Steindachner, 1882

Figs. 33 , 37-38 , Tables 9 -15

Cetopsis plumbeus Steindachner, 1882: 178 [type locality: [ Ecuador] Canelos].–1883: 31, pl. 6, fig. 3 [more complete description].– Boulenger, 1887: 276 [eastern Ecuador, Sarayacu].– Eigenmann & Eigenmann, 1888: 157 [listing].– 1890: 318 [key and listing].–1891: 36 [listing].– Pearson, 1924: 16 [ Bolivia, río Colorado, lower [río] Bopi].–1937a: 94 [ Peru, río Marañon].– Fowler, 1941: 472 [ Peru: río Marañon].–1945: 70 [ Peru: río Marañon]. [Not Perugia, 1897: 23; Pearson, 1924: 16; Pearson, 1937b: 111; Fowler, 1940b:97].

Cetopsis macroteronema Boulenger, 1898b: 6 [type locality: río Zamora, Equateur oriental (=eastern Ecuador)].– Tortonese, 1940: 137 [type despository].

Pseudocetopsis macroteronema .– Eigenmann, 1910: 398 [in listing].– Gosline, 1945: 55 [listing].– Fowler, 1954: 5 [eastern Ecuador].– Ovchynnyk, 1967: 35 [ Ecuador, río Zamora]; 1968: 255 [ Ecuador, río Zamora].

Pseudocetopsis plumbeus plumbeus .– Schultz, 1944: 253 [key].– Evers & Seidel, 2002: 741 [listing]. [Not Cala, 1977: 11]

Hemicetopsis plumbeus .–Eigenmann & Allen, 1942: 149 [literature compilation].– Gosline, 1945: 54 [listing].–Terrazas- Urquidi, 1970: 21 [ Bolivia]; Burgess, 1989: 292 [in listing].

Pseudocetopsis plumbeus .– Fowler, 1954: 5 [literature compilation].– Ovchynnyk, 1967: 35 [ Ecuador: Sarayacu, Canelos]; 1968: 255 [ Ecuador: Sarayacu, Canelos].– Barriga, 1991: 57 [ Ecuador, eastern drainages; common name]; 1994a: 31 [ Ecuador, Parque NacionalYasuni].– Saul, 1975: 117 [ Ecuador, río Aguarico; food habits].– Ortega & Vari, 1986: 15 [ Peru; common name].– Stewart et al., 1987: 33 [ Ecuador, based on Saul, 1975].–Ibarra & Stewart [ Ecuador, río Napo].– [Not Baskin et al., 1980: 184; Péfaur, 1988: 474].

Pseudocetopsis macropteronema .–Evers & Seidel, 2002: 741 [listing; species name misspelled].

Pseudocetopsis plumbea .–Vari & Ferraris, 2003: 258 [in check list; synonymy, distribution, common names].

Diagnosis. Cetopsis plumbea can be distinguished from all of its congeners by the combination of the presence of an eye, the conical teeth on the vomer and dentary, the rounded posterior nares that is distinctly separated from the contralateral nares by a distance greater than the width of the posterior nares, the wide mouth, the width of which is one-half of HL, the absence of a dark humeral spot, the absence of a posteriorly-rounded, variably-developed, bilobed patch of dark pigmentation at the base of the caudal fin, the absence of a pattern of dark pigmentation across the caudal fin other than for along its distal margin, the presence of approximately eye-size, dark spots on the lateral surface of the body, the presence of dark chromatophores along the anterior and lateral margins of the snout, the absence of dark pigmentation along the distal portions of the pectoral and anal fins, and the possession of 10 to 14 precaudal vertebrae and 45 to 50 total vertebrae.

Description. Body moderately-elongate, slightly-compressed laterally anteriorly and becoming progressively distinctlycompressed posteriorly. Body depth at dorsal-fin origin approximately 0.27-0.28 of SL, and approximately equal to HL. Lateral line on body complete, unbranched, and midlateral; extending from vertical through pectoral-fin base to hypural plate with short, dorsal bend on hypural plate. Dorsal profile of body slightly convex from nape to dorsal-fin origin and nearly straight from dorsal-fin origin to caudal-fin base. Ventral profile of body convex along abdomen, approximately straight, but posterodorsally-slanted, along base of anal fin. Caudal-peduncle depth slightly greater than caudal-peduncle length.

Head in profile acutely triangular overall with bluntlyrounded snout. Dorsal profile of head slightly to distinctly convex from tip of snout to nape. Ventral profile of head slightly convex. Margin of snout in dorsal view rounded to bluntly triangular. Postorbital margins of head running nearly in parallel from dorsal view. Enlarged jaw musculature not apparent externally on dorsal surface of postorbital portion of head contrary to condition in some other species of the Cetopsinae .

Opercular membrane attaching to isthmus only anterior of vertical through pectoral-fin insertion. Opercular opening moderate; extending ventral of pectoral-fin insertion by distance equal to length of snout plus eye and extending dorsal of pectoral-fin insertion by distance slightly less than snout length.

Eye situated on lateral surface of head; located entirely dorsal to horizontal extending through pectoral-fin insertion; eye visible in dorsal view, but not in ventral view, of head. Middle of orbit at approximately anterior 0.29 of HL. Eye diameter approximately one-half of snout length. Interorbital width approximately equal to distance from tip of snout to posterior margin of orbit. Anterior narial opening circular, surrounded by short, anteriorly-directed, tubular rim of skin. Opening of anterior nares located along horizontal extending through maxillary-barbel origin and ventral of horizontal extending through tip of snout. Distance between anterior nares approximately equal to snout length. Posterior narial opening located on dorsal surface of head, situated along vertical through anterior margin of orbit; narial opening rounded and with anterior two-thirds of aperture surrounded by flap of skin with anterior portion of flap highest.

Mouth inferior; its width approximately one-half of HL. Margin of lower jaw gently rounded, its posterior limit reaching to vertical through posterior margin of orbit. Premaxillary tooth patch in form of gently-arched band, continuous across midline and with anterior margin convex and posterior margin concave and running in parallel to anterior margin. Teeth on premaxilla small, conical, and sharply-pointed, with teeth arranged in three or four, irregular rows of uniform-sized teeth. Vomerine teeth arranged in single, irregular row continuous across midline. Vomerine teeth stout, conical, and much larger than teeth on premaxilla or dentary. Dentary teeth comparable in shape to, but larger in size than, premaxillary teeth. Dentary dentition consisting of two regular rows medially, that taper to one row laterally.

Maxillary barbel slender, its length approximately equal to distance from tip of snout to posterior margin of eye, and approximately one-third of HL; barbel origin located ventral to middle of orbit. Medial mental barbel slightly shorter than lateral mental barbel with latter approximately equal in length to maxillary barbel. Medial mental-barbel origin located along vertical through rictus. Lateral mental-barbel origin situated slightly posterior of vertical through medial mental-barbel origin. Tips of adpressed mental barbels falling short of posterior margin of opercle.

Dorsal fin moderately large overall with length of dorsalfin base approximately 0.40-0.41 of HL. Length of longest branched dorsal-fin ray equal to two-thirds of HL. Dorsal-fin spinelet absent. First dorsal-fin ray not spinous but with at least short, distal filament in mature males. Distal margin of dorsal fin straight, or nearly straight, with first ray longest. Dorsal-fin origin located at approximately anterior 0.27-0.28 of SL and along vertical extending through middle of adpressed pectoral fin. Tip of adpressed dorsal fin reaching nearly to vertical through vent. Posterior most dorsal-fin ray without posterior, membranous attachment to body.

Caudal fin moderately-forked, symmetrical; tips of lobes bluntly pointed. Length of longest caudal-fin ray approximately 1.5 to 1.75 times length of middle fin rays.

Base of anal fin long. Anal-fin origin located slightly posterior of middle of SL. Anal-fin margin straight in females and immature males, with posterior most unbranched anal-fin ray longest and subsequent fin rays becoming gradually shorter. Anal-fin margin slightly convex in mature males. Posterior most anal-fin ray without posterior, membranous attachment to body.

Pelvic fin moderate; distal margin nearly straight, with first ray longest. Pelvic-fin insertion located anterior to middle of SL and along vertical through posterior portion of base of dorsal fin. Tip of adpressed pelvic fin extending approximately to middle of SL, and past anterior margin of vent. Medial most pelvic-fin ray with membranous attachment to body along basal two-thirds of its length.

Pectoral-fin length approximately two-thirds of HL. Pectoral-fin margin slightly convex, with first ray longest and prolonged into filament; filament proportionally longer in mature males. First pectoral-fin ray not spinous.

Coloration in alcohol. Coloration somewhat intraspecifically variable ( Figs. 37 , 38 ) with some specimens retaining grayish or silvery background coloration on body. Dark pigmentation covering dorsal portion of head from snout to rear of head. Irregular spot of variably-developed, dark pigmentation present posteroventral to orbit in all specimens from single population sample that originated in eastern Ecuador (ZMH 1671), but such dark pigmentation absent in all other examined material herein assigned to Cetopsis plumbea . Dorsal portion of body dark. Lateral surface of body irregularly covered with dark spots of pigmentation of variable sizes; with some individuals having spots nearly uniformly-distributed and others having irregular, dark spots up to size of eye, some of which coalesce to some varying degrees. Spots more concentrated dorsally. Ventral surface of head and body pale or with few dark spots.

Dorsal fin covered by dark pigmentation, with pigmentation more concentrated basally. Caudal fin covered with variably-developed, scattered, dark pigmentation except for narrow clear band along distal margins. Anal fin with scattered, dark pigmentation along base and with dark pigmentation extending varying distances onto fin, but with distal portions of fin usually pale and without distinct distal band on fin. Pectoral fin with scattered, dark pigmentation on at least anterior rays and with distal margin and posterior rays often pale. Pelvic fin with scattered, dark pigmentation on base and dorsal surface of first ray.

Maxillary barbel dusky basally with distal portion pale. Mental barbels pale.

Sexual dimorphism. The presumed males of Cetopsis plumbea have a distal filament on the first ray of the dorsal fin. That filament is absent in females and immature males of the species. Mature males also have the filament on the first pectoral-fin ray proportionally more elongate than the extension of the ray present in conspecific females and immature males. Mature males have an anal-fin margin that is distinctly convex contrary to the straight anal-fin margin that is characteristic of females and immature males of the species. The largest mature males of the species examined in this study are all smaller than the largest examined females.

Distribution. Cetopsis plumbea occurs in the western portions of the Amazon basin in eastern Ecuador, southeastern Peru, and northeastern Bolivia ( Fig. 33 ).

Common Name. Ecuador: “Ciego” ( Barriga, 1991: 57); Peru: “Canero” ( Ortega & Vari, 1986: 15).

Ecology. Saul (1975: 117) reported that Cetopsis plumbea (cited therein as Pseudocetopsis plumbeus ) feeds on a variety of terrestrial and aquatic insects. It inhabits streams with moderate current and a depth of up to 1 m, occurring within such streams in areas over sand substrates but lacking vegetation.

Remarks. Cetopsis plumbea is similar in overall appearance to C. gobioides , a species that inhabits various river systems in the eastern and southeastern portions of South America. As discussed under “Remarks” for C. gobioides , these two species can be distinguished by various features.

The very short original description of Cetopsis plumbeus by Steindachner (1882: 78) was uninformative as to the number of specimens that served as the basis for the description of the species, and that author briefly reported the type locality as “Canelos.” In a subsequent redescription of the species, Steindachner (1883: 31, pl. 6, fig. 3) provided a more extensive description and accompanying illustration of C. plumbeus and expanded the locality information to “Canelos ( Ecuador),” a location in the Amazon basin versant of that country.

Two lots of specimens identified as Cetopsis plumbeus were located in the NMW collections (NMW 47381-3; NMW 47383-3) that match the locality information (Canelos) cited in the original description of the species. The two specimens forming NMW 47381-3 (52.8 mm SL, 60.8 mm TL; 62.6 mm SL, ~ 70 mm TL) approximate the lengths for the two specimens (“6-7 Ctm” (=cm)) reported by Steindachner in his redescription of Cetopsis plumbeus ( Steindachner, 1883: 31) , allowing for rounding to the nearest centimeter. The date on the label associated with this lot (NMW 47381-3 is stated as “ Juli 1883 ” (July, 1883; H. Wellendorf, NMW; pers. commun., 16 Oct 1998) which, if it both were correct and represented the date on which the sample was collected, would indicate that these specimens could not be syntypes of C. plumbeus inasmuch as the original description of that species appeared in 1882. It is, however, likely that 1883 represents the year when these specimens were accessioned into the NMW collections (H. Wellendorf, NMW; pers. commun., 16 Oct 1998.) and we consequently consider these two specimens to be syntypes of Cetopsis plumbeus .

The label information associated with the second lot (NMW 47383-3) from Canelos has a notation “Knop, gez. T.VI.3” that indicated that Steindachner’s illustrator, Konopitsky, used a specimen from that lot as the basis for an illustration (H. Wellendorf, NMW; pers. commun., 16 Oct 1998). The label information matches that associated with the illustration published by Steindachner (1883: 31, pl. 6, fig. 3) that was cited in the species account as “Taf. VI, fig. 3.” The specimen illustrated by Steindachner (1883, pl. 6, fig. 3) was approximately 45 mm SL (specimen illustrated at two times natural size in that plate), a length very close to that of one of the three specimens (46 mm SL) in NMW 47383-3 (the other two specimens in the lot are 48 and 56 mm SL). Furthermore, the residual dark pigmentation present on this specimen matches the pattern that is present in the illustrated specimen. Although the acquisition date on the label is “1884.I” (= January 1884), this indicates that the material was entered into the NMW acquisition records on that date rather than demonstrating that the lot was received in 1884 (H. Wellendorf, NMW; pers. commun., 16 Oct 1998). Given the available information we designate the illustrated 46 mm SL specimen (NMW 47383-1) as the lectotype of Cetopsis plumbeus and the other syntypes thereby become paralectotypes (NMW 47381-2-3; NMW 47383-3).

Boulenger (1898: 6) described Cetopsis macroteronema based on two obviously mature males from the río Zamora of eastern Ecuador, a location relatively close to the type locality of Cetopsis plumbeus at Canelos, Ecuador. In his description of Cetopsis macroteronema, Boulenger limited his comparisons of that species to the original description of Cetopsis ventralis described Gill (1870: 95) with an erroneous stated type locality of “Maranon or Upper Amazon, and Napo Rivers” (see “Remarks” under Paracetopsis bleekeri concerning the reported type locality). Cetopsis ventralis is, however, a junior synonym of Paracetopsis bleekeri , a species endemic to the Pacific Ocean versant of Ecuador (see Remarks” under Paracetopsis bleekeri ). Paracetopsis bleekeri differs dramatically in a number of internal and external features from the complex of species, including Cetopsis macroteronema , that are externally similar to C. plumbea and in retrospect was an inappropriate basis of comparison for C. macroteronema . An examination of one of the syntypes of Cetopsis macroteronema (BMNH 1898.11.4.11) failed to reveal any differences between C. macroteronema and C. plumbea in the character systems examined in this study, and the two species are herein considered conspecific.

Schultz (1944: 253) placed two nominal forms (the Cetopsis orinoco and C. motatanensis of this study) as subspecies of Pseudocetopsis plumbeus without any discussion as to the basis for those subspecific assignments. The three nominal forms differ from each other in a number of often trenchant features and each is consequently herein considered to be a distinct species.

Cetopsis plumbeus was reported by Perugia (1897: 23) from the río Beni basin, with this record, in turn, apparently the basis for the inclusion of that species in the Bolivian fish fauna by Fowler (1945: 5) and Terrazas-Urquidi (1970: 21). Although Cetopsis plumbea does occur in the rivers of northeastern Bolivia, our results reveal that C. pearsoni also inhabits that drainage basins and we are, thus, unable to determine which of these two species served as the basis for the Perugia record and its reiteration by subsequent authors.

Cetopsis plumbea (under various generic combinations) has been reported from several areas distant from the known distribution of that species as documented by the specimens examined in this study. Following an examination of specimens that served as the basis of those records and/or given the locality from which the samples originated, we have been able to assign various of those citations to C. montana and C. pearsoni (see “Remarks” under those species). Ortega (1996: 471) cited Pseudocetopsis plumbeus from the Parque Nacional Manu in southeastern Peru. That locality is within the range of C. plumbea , but given that C. montana also occurs in the río Madre de Dios basin, we are unable to unequivocally determine which of these two species was present at the Parque Nacional Manu.

Cetopsis plumbea was reported from the Tambopata- Candamo Reserved Zone, also in the río Madre de Dios basin of southeastern Peru by Chang (1998: 26, cited therein as Pseudocetopsis plumbea ). This record has been confirmed by the examination of a part of the series of specimens that served as the basis for that report of C. plumbea .

Material examined. 70 specimens (19-135.5 mm SL). Bolivia. La Paz: lower río Bopi (=Boopi), of río Colorado drainage system (approximately 15°41’S, 67°15’W), CAS 16019, 4 (62-118; formerly IU 17255). Ecuador. Napo: río Pucuno, tributary of río Suno (0°47’S, 77°16’W), USNM 163898, 2 (75-102). Río Aguarico at Santa Cecilia (0°06’N, 76°51’W), ANSP 130604, 1 (27). Pastaza: río Curary [=Curaray], ZMH 1671, 8 (44-90). Canelos (1°35’S, 77°45’W), NMW 47383-1, 1 (46; lectotype of Cetopsis plumbeus , designated herein); NMW 47381-1 and 3, 2 (52.8-62.6, paralectotypes of Cetopsis plumbeus ); NMW 47383-2-3, 2 (48- 56, paralectotypes of Cetopsis plumbeus ). Río Pastaza and río Pindo, Puyo, 1000 ft elevation (1°28’S, 77°59’W), UMMZ 203882, 1 (135.5). Río Payamino, 23.3 km upstream from mouth in río Napo, FMNH 111692, 1 (34). Río Payamino, 12.3 km upstream from mouth in río Napo FMNH 111693, 1 (30). Río Napo, río Suno, lower 0.5 km and at its mouth, FMNH 111694, 1 (37). Río Napo, río Arajuno, lower reaches, 1 (46). Río Tutapischco, just upstream from mouth in río Payamino, near San Jose de Payamino (0°30’S, 77°18’W), FMNH 111696, 2 (80-81). Río Napo, río Arajuno, lower reaching, FMNH 111695, 1 (46). Sucumbios: río La Bermeja, in front of comunidad Shuar (approximately 0°10’N, 76°25’W), MEPN 1528, 3 (43.5-69). Zamora Chinchipe: Playa del río Nangaritza approximately 5 km upriver of Paguisha and Playa de Mayayacu Bajo (3°59’S, 78°36’W), MEPN 1529, 1 (78). Río Zamora, BMNH 1898.11.4.11, 1 (89, syntype of Cetopsis macroteronema ). Peru. Amazonas: río Marañon, vicinity of Balsas (6°51.9’S, 77°59.9’W), ROM 55377, 1 (65). Río Marañon, Pusoc (Guayabamba) above Balsas, approximately 3700 ft (= 1128 m) (locality at approximately 6°53’S, 78°00’W), CAS 77025, 1 (47; formerly IU 17624). 500 m upriver from Caterpiza (latter locality is at 3°55’S, 77°42’W), LACM 42010-1, 1 (65). Cajamarca: río Marañon, Tingo de Pauca, at the mouth of río Crisnejas (7°21’S, 77°50’W), CAS 77026, 3 (57-80; formerly IU 17623). Cuzco: río Marcapata, Hacienda Cadena, FMNH 71024, 1 (122). Huancavelica: río Mantaro, Quintabamba, MUSM 6647, 1 (119). Puno: Carabaya, río Explanada, Zona Reservada Tambopata-Candamo (13°24’S, 70°01’19"W), MUSM 11689, 20 (50-92). Huanuco: río Llullapichis, approximately 2 km upstream from mouth (at río Pachitea) (9°39.9’S, 74°57.9’W), ROM 55821, 1 (55). Madre de Dios: Mouth of río Carbon, below Atalaya on N/S road (12°53’S, 71°20’W), ANSP 143982, 1 (94); ANSP 143983, 1 (85.6); ANSP 151520, 1 (96.0). Alto Madre de Dios at Shintuya (12°40’S, 71°17’W), ANSP 143984, 3 (30-31); ANSP 143985, 2 (19-24). Manu, Parque Nacional Manu, Pakitza, Quebrada Pachija, MUSM 4201, 1 (71, specimen cleared and stained).

Figures

Fig. 33. Map of central and northern SouthAmerica showing geographic distribution of Cetopsis orinoco (1 = holotype locality of Pseudocetopsis plumbeus orinoco), Cetopsis othonops (2 = holotype locality of Hemicetopsis othonops), Cetopsis parma (3 = holotype locality), Cetopsis pearsoni (4 = holotype locality), and Cetopsis plumbea (5 = lectotype locality of Cetopsis plumbeus) (some symbols represent more that one locality and/or lot of specimens).

Fig. 37. Cetopsis plumbea, MUSM 11689, 64.1 mm SL; Peru, Puno, Carabaya, río Explanada, Zona Reservada Tambopata- Candamo (13°24’S,70°01’19"W).

Fig. 38. Cetopsis plumbea, MEPN 1529, 78 mm SL; Ecuador, Zamora-Chinchipe, Playa del río Nangaritza, approximately 5 km upriver of Paguisha and Playa de Mayayacu Bajo (3°59’S, 78°36’W).