Comprehensive Description
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Ichthyoelephas longirostris (Steindachner, 1879)
Prochilodus longirostris Steindachner, 1879b:195 [type locality: Cauca (=Río Cauca, Colombia), restricted herein to Colombia, Antióquia, Río Cauca, near to Cáceres; brief abstract of more extensive species description published in Steindachner, 1879c]; 1879c:188 (page 70 of separate) [more extensive description of species]; 1880:69 [Colombia: Rio Cauca; expanded species description].—Eigenmann and Eigenmann, 1891:48 [in listing of South American fishes].—Eigenmann, 1907b:768 [lateral-line scale count]; 1910:424 [in listing of South American fishes]; 1920b:16 [(Río) Magdalena basin]; 1922a:112 [Cauca; based upon Steindachner, 1879c].—Posada Arango, 1909:300 [Cauca].—Ridoutt, 1939:69 [in key to species of Prochilodus].—Fowler, 1942:133 [Colombia, Ríos Magdalena and Cauca].—Böhlke, 1958: 112 [features shared with Ichthyoelephas humeralis noted].—[Not Magalães, 1931:239.]
Ichthyoelephas pataló Posada Arango, 1909:302, fig on page 301 [type locality: Colombia, Samana (=Río Samaná)].
Ichthyoelephas longirostris.—Miles, 1943:43 [Colombia, Río Cauca basin; shift of species from Prochilodus to Ichthyoelephas; repeat of original description of species; illustration of external head osteology]; 1947:133 [Colombia, Río Magdalena basin, upper Rio Cauca basin]; 1973:39 [repeat of account in Miles, 1943].—Mago-Leccia, 1972:68 [Colombia].—Roberts, 1973b:214, fig. 1 [Colombia].—Patiño R., 1973:81, fig. 29 [Colombia, Río Cauca basin, distribution, life history, anthropogenic effects on populations].—Fowler, 1975:357 [literature compilation].—Géry, 1977:226 unnumbered figure on page 222 [Colombia].—Román-Valencia, 1988:111 [Colombia, Departamente de Quindio, upper Río Cauca]; 1993:71 [life history; Colombia, upper Rio Cauca basin, Río La Vicja].—Cala, 1995:49 [Colombia, Río Magdalena basin, Betania Reservoir; reductions of populations in and upriver of that impoudment].—Mojica-C., 1999:554 [Colombia, Río Magdalena, Río Cesar, Rio San Jorgc, upper Rio Cauca].—Sánchez, M. et al., 2000:218 [Colombia, Departamento del Huila, upper Río Magdalena; economic importance].—Román-Valencia and Ortiz-Muñoz, 2001:33 [Colombia: Río Magdalena-Cauca basin Río Rancheria (state of Guajira); reproduction].
Ichthyoëlephas longirostris.—Dahl et al., 1963:43 [Colombia, Río San Jorge; habitat preferences; common name].—Román-Valencia, 1995, unpaginated [Colombia, upper Río Cauca basin, Río La Vieja; details of life history].
Ichthyoelephas longirostris longirostris.—Dahl, 1971:107 [Colombia, upper portions of Rio Magdalena basin and its tributaries; food habits, economic importance].
Ichthyoelephas longirostris neglectus Dahl, 1971:108 [type locality: Colombia, ciertas ciénegas adyacentes al Bajo Rio Magdalena, desde la Ciénega de Plata hacia abajo (=certain “ciénegas” (floodplain pools and swamps) adjacent to lower Río Magdalena, from Ciénega de Plato downriver); common name].—Román-Valencia, 1993b:78 [as synonym of Ichthyoelephas longirostris].
DIAGNOSIS.—Ichthyoelephas longirostris differs from the only other member of the genus, I. humeralis, in the snout length (48.8%–55.7% of HL versus 34.5%–45.4% of HL, respectively), the horizontal width of the orbit (11.1%–16.3% versus 19.4%–36.1% of HL, respectively), the number of horizontal rows of scales between the dorsal-fin origin and the lateral line (typically 7, rarely 6, versus 6, respectively), and the number of teeth in the inner row of teeth on each side of the upper jaw (50 to 76 versus 27 to 47, respectively). The latter feature is an autapomorphy for I. longirostris, along with the reduction in the extent of the exposure of the parietal on the dorsal surface of the neurocranium (see “Parietal” under “Character Description and Analysis”).
DESCRIPTION.—Morphometric and meristic data for Ichthyoelephas longirostris presented in Table 4. Body moderately high, typically subcylindrical, but relatively deeper in some larger, apparently female specimens. Greatest body depth at dorsal-fin origin in most specimens, but slightly anterior to that point in some smaller individuals. Dorsal profile of head very gently convex. Predorsal profile of body moderately convex. Dorsal profile of body posteroventrally inclined along dorsal-fin base; gently convex from posterior of dorsal-fin base to adipose-fin origin, and concave along caudal peduncle. Predorsal portion of body with slight median ridge. Postdorsal region of body transversely obtusely rounded. Ventral profile of body gently convex from tip of lower jaw to posterior of anal-fin base. Ventral profile of caudal peduncle concave. Prepelvic region transversely flattened from slightly posterior of vertical through pectoral-fin insertion to proximate to pelvic-fin insertion, more distinctly flattened posteriorly. Region between pelvic-fin insertion and anus transversely rounded and without distinct median keel.
Head profile pointed. Mouth subterminal and very broad. Snout length distinctly greater than horizontal width of orbit. Nares of each side of head close to each other; anterior nares circular, posterior crescent shaped. Adipose eyelid present but poorly developed; most highly developed along anterior border but with most of eye uncovered. Lips forming oral disk when protracted.
Functional teeth in two rows in each jaw. All teeth falciform and movably implanted in flesh that overlies jaws. Inner tooth series in each jaw with 50 to 76 teeth on left side of upper jaw and 35 to 70 teeth on left side of lower jaw. Outer row of teeth with approximately 200 teeth on each side of upper jaw and approximately 200 teeth on each side of lower jaw in lectotype. Upper and lower lips bordered by numerous transverse fleshy ridges.
Scales cycloid. Scales along middorsal series between posterior of dorsal-fin base and adipose-fin origin with spatulate membranous process along posterior border of each scale in that series. Lateral line with 38 to 40 (45.0% of specimens with either 38 or 39) pored scales; 6 or 7 (86% of specimens with 7) horizontal rows of scales between dorsal-fin origin and lateral line; 5 or 6 (71.5% of specimens with 5) horizontal rows of scales between pelvic-fin insertion and lateral line; 5 or 6 (78.6% of specimens with 5) horizontal rows of scales between anal-fin origin and lateral line; 13 or 14 (78.6% of specimens with 13) median predorsal scales; 12 to 14 (50% of specimens with 14) scales in middorsal series between posterior of dorsal-fin base and adipose-fin origin; 15 or 16 (78.6% of specimens with 16) horizontal rows of scales around caudal peduncle.
Vertebrae 33 to 35 (83.3% of specimens with 35).
Dorsal fin preceded by small, nonbifurcate procumbent spine. Dorsal-fin rays (including procumbent spine) iii,10 [iii,10]; anal-fin rays iii,7 or 8 (iii,8 most frequent) [iii,8]; pectoral-fin rays i,15 or 16 (i,16 most frequent) [i,16]; pelvic-fin rays i,8 [i,8]; principal caudal-fin rays 10/9 [10/9].
Dorsal fin truncate distally; posterior unbranched and anterior branched rays longest and subequal. Dorsal-fin origin located closer to tip of snout than to caudal-fin base. Greatest length of adipose fin approximately equal to distance slightly greater than horizontal width of orbit. Adipose-fin origin located along vertical that passes though posterior one-half of anal-fin base. Pectoral fin distally pointed. Tip of adpressed pectoral fin reaching approximately two-thirds of distance between pectoral- and pelvic-fin insertions. Pelvic fin falcate or with distal margin straight. Pelvic-fin origin located slightly posterior of vertical that passes through posterior one-third of dorsal-fin base. Tip of adpressed pelvic fin reaching approximately two-thirds to three-fourths of distance from pelvic-fin insertion to anus. Axillary scale present, length approximately one-third that of pelvic fin. Posterior unbranched and anterior branched anal-fin rays longest and subequal. Caudal fin distinctly bifurcate.
COLORATION IN ALCOHOL.—Ground coloration yellowish or light brown, with dorsal portion of head and body darker. Scales 4 through 6 of lateral line series with irregular patches of dark pigmentation in more recently collected specimens, with pigmentation on scale 5 most intense; dark pigmentation not apparent in some nontype specimens (NRM 24960). Scales 3 and 4 of horizontal scale row immediately ventral of lateral line series slightly pigmented with dark chromatophores in relatively recently collected, large specimens; pigmentation only apparent in some specimens in NRM 24960 collected more than 60 years ago.
Dorsal fin with 5 very irregular stripes beginning at rear of fifth branched ray and extending posteriorly across fin approximately parallel to base of fin. Adipose-fin margin outlined by dark pigmentation. Pectoral, pelvic, and anal fins dusky. Median caudal-fin rays darker than rest of fin. Iris brownish red, with diffuse dark areas dorsally and ventrally.
COLORATION IN LIFE (based upon description by Román-Valencia (1993b:78)).—Body dark green dorsally and golden white ventrally, with a dark blue band along the side of the body over yellow marks. Dorsal fin yellow-green, with dark band at base. Anal, pectoral, pelvic, and adipose fins reddish. Caudal fin dark green except for reddish band distally.
DISTRIBUTION.—Examined samples of Ichthyoelephas longirostris originated in the Río Cauca-Río Magdalena drainage basin of northern Colombia (Figure 30, stars). Patiño R. (1973:81) reports the species from the Río Timba, Río Rio-Claro, Río Jamundi, Río Piedras, and some tributaries to the Río La Vieja. all in the Río Cauca-Río Magdalena basin. Román-Valencia and Ortiz-Muñoz (2001:35) reported that I. longirostris occurs in the Río Rancheria, an independent coastal drainage in the state of Guajira, on the Peninsula of Guajira (approximately 11°34′N, 72°54′W), Colombia. This is the first record of Ichthyoelephas longirostris from outside of the Río Cauca-Río Magdalena drainage basin.
COMMON NAME.—Pataló, getudo, hocicón, jetón, moreno, besote, and besugo (Colombia).
LIFE HISTORY AND ECOLOGY.—Patiño R. (1973:81–82) reported that Ichthyoelephas longirostris reaches 80 cm (presumably TL) and that some individuals achieve even larger sizes. The species feeds on the algal covering that grows on rocks in clear-water rivers. As a consequence of their dependence upon that food source, populations of I. longirostris have been adversely effected by the siltation that is a consequence of the increased erosion brought about by deforestation. The ready visibility of I. longirostris in clear waters and market demand because of their fine taste has led to intense fishing pressure and destructive fishing methods, including the use of dynamite. This in turn has resulted in the elimination of populations of I. longirostris in some areas (Dahl, 1971:107). Sánchez et al. (2000:218–219) reported that the species is of commercial importance in the upper Río Magdalena basin below the Betania impoundment, being one of the most expensive fishes in the markets of the region. According to Patiño R. (1973:81–82), I. longirostris reproduces in running waters, with the migrating schools using leaps to overcome obstacles to their migration. Details of its life history have been discussed by Román-Valencia (1993:71) and Román-Valencia and Ortiz-Muñoz (2001:33), who provided additional information on its reproduction and habitat.
MATERIAL EXAMINED.—14 specimens (14, 232.9–431.0 mm SL).
COLOMBIA. Antióquia: Río Cauca, near to Cáceres, NMW 56680, 1 (366.3, lectotype of Ichthyoelephas longirostris) [1R]; NMW 56681, 1 (306.5, paralectotype of Ichthyoelephas longirostris) [1R], NMW 56682:1–2, 2 (2, 381.1–390.9, paralectotypes of Ichthyoelephas longirostris) [1R]. Caldas: At or near junction of Rios Samaná [and] La Miel, near La Dorada (5°29′N, 74°40′W), CAS 150411, 1 (431.0, formerly SU 50411); CAS 150412, 1 (335.2, formerly SU 50412). Cauca: Río Cauca basin (3°07′N, 76°37′W), Timba, 1100 m asl, NRM 24960, 5 (5, 232.9–263.1), NRM 24966, 1 (259.9). Valle: Laguna de Sonso, near to Instituto de Piscicultura Tropical de Buga, Município de Buga, valley of Río Cauca, MZUSP 55145, 2 (2, 311.2–325.3; 1 specimen cleared and counterstained for bone and cartilage) [2R].
Prochilodus Agassiz in Spix and Agassiz, 1829:62 [type species: Prochilodus argenteus Agassiz in Spix and Agassiz, 1829, by subsequent designation (Eigenmann, 1910:424)]. Gender masculine.
Pacu Agassiz in Spix and Agassiz, 1829:62 [type species: Prochilodus argenteus Agassiz in Spix and Agassiz, 1829, by subsequent designation (Eigenmann, 1910:424)]. Gender masculine.
Paca.—Valenciennes, 1836, no page, pl. 8: fig. 3 [misspelling of Pacu Agassiz in Spix and Agassiz, 1829].
Chilomyzon Fowler, 1906:309 [type species: Prochilodus steindachneri Fowler, 1906 (= Prochilodus vimboides Kner, 1859), by monotypy. Proposed as a subgenus of Prochilodus Agassiz in Spix and Agassiz, 1829]. Gender masculine.
Pacus.—Fowler, 1941:168 [incorrect spelling of Pacu Agassiz in Spix and Agassiz, 1829].
DIAGNOSIS.—Prochilodus is a monophyletic group of 13 species delimited by the characters discussed in the “Monophyly of Prochilodus,” above. Prochilodus, furthermore, differs from Ichthyoelephas and Semaprochilodus, the other genera in the Prochilodontidae, in the following combination of characters: the dorsal fin is preceded by an anteroventrally branched procumbent spine; the fleshy lips are moderately developed; the teeth are short and spatulate from anterior view; there are 10 to 29 teeth on each side of the inner tooth row of the upper jaw and 6 to 18 teeth on each side of the inner tooth row of the lower jaw; the scales are spinoid (ctenoid of most previous authors; see “Methods and Materials”) with small, flat spines in two approximately alternating rows along the posterior exposed margin; the scales in the middorsal series between the posterior of the dorsal-fin base and the adipose-fin origin are similar in form to those of adjoining portions of the body and lack a membranous spatulate process along their posterior margin.
In addition, Prochilodus species have the dorsal fin truncate, either rounded or slightly pointed distally; the anal fin gently falcate; the caudal fin bifurcate or gently emarginate; a dorsal fin with 2 to 10 irregular dark stripes that begin along its anterior margin and extend across the fin approximately parallel to the fin base. The pectoral, pelvic, and anal fins are hyaline; the caudal fin is hyaline or with 2 to 8 irregular, wavy, vertical bars formed of small dark marks; juveniles and smaller specimens have 4 to 24 vertical pigmentation patches on the body formed by fields of dark chromatophores with patches having an overall form of narrow isosceles triangles with apexes located on the middle of the ventrolateral portion of the body and bases on the dorsomedial region of the body.
Prochilodus species as a group have 34 to 64 pored scales; 5 to 13 horizontal rows of scales between the dorsal-fin origin and the lateral line; 5 to 11 horizontal rows of scales between the pelvic-fin insertion and the lateral line; 4 to 9 horizontal rows of scales between the anal-fin origin and the lateral line; 11 to 22 median predorsal scales; 11 to 23 scales in the middorsal series between the posterior of the dorsal-fin base and the adipose-fin origin; 13 to 25 horizontal rows of scales around the caudal peduncle; and 36 to 45 vertebrae.
- bibliyografik atıf
- Castro, Ricardo M. C. and Vari, Richard P. 2004. "Detritivores of the South American fish family Prochilodontidae (Teleostei:Ostariophysi:Characiformes) : a phylogenetic and revisionary study." Smithsonian Contributions to Zoology. 1-189. https://doi.org/10.5479/si.00810282.622