Comprehensive Description
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англиски
)
добавил Smithsonian Contributions to Zoology
Creagrutus paralacus
Creagrutus beni.—Schultz, 1944b:336 [Venezuela: Lago Maracaibo basin: Río Cobre. Río Gonzáles, Río Chama. Río Motatán, Río Táchira, Río Barregas (= Albarregas); not specimens from Río Orinoco basin].—Mago-Leccia, 1970:70 [Venezuela: in part, Lago Maracaibo].
DIAGNOSIS.—The relatively narrow infraorbital series, the posterior position of the dorsal fin relative to the pelvic-fin origin, the nearly straight distal margins of the dorsal and anal fins, and the presence of hooks on the lateral surface of the pelvic rays of males are possible autapomorphies for Creagrutus paralacus. A final evaluation must await thorough studies of congeners to the east of the Andes. The combination of unmodified lateral-line scales, a completely pored lateral line, and a relatively small third infraorbital distinguishes Creagrutus paralacus from its trans-Andean congeners. Creagrutus paralacus can be additionally distinguished from all trans-Andean congeners by its limited pigmentation on the basal portions of the middle caudal fin rays (versus a distinct spot or horizontal bar on those rays in nigrostigmatus, maracaiboensis, hildebrandi, and affinis), its relatively rotund, not deep body (versus the highly compressed and very deep body of magdalenae), and number of lateral-line scales (36 to 38 versus 39 to 42 in caucanus, 29 to 31 in maracaiboensis, and 30 to 32 in nigrostigmatus).
DESCRIPTION.—Body moderately elongate, only slightly compressed relative to other trans-Andean Creagrutus species. Greatest body depth approximately midway between vertical lines through origins of pectoral and pelvic fins. Dorsal profile of head distinctly convex from margin of upper lip to region between vertical through posterior nares and vertical through anterior margin of orbit; approximately straight from that area to posterior end of supraoccipital. Dorsal profile of body with notable change in alignment relative to that of head, convex from posterior portion of supraoccipital to dorsal-fin origin; convexity asymmetrical, most pronounced in anterior one-third of predorsal profile. Dorsal profile nearly straight from dorsal-fin origin to caudal peduncle. Ventral profile of head with barely obvious angle approximately midway between margin of upper lip and posterior of dentary; some non-type specimens with angle more pronounced. Ventral profile of remainder of head and body posteriorly to anal fin slightly convex.
Head large with small orbit. Upper jaw distinctly longer than and overhanging lower jaw. Anterior portion of snout quite fleshy, with minute papillae distributed over anterior portion of snout and with numerous papillae continuing onto upper lip, margin of upper jaw, and into mouth on fleshy flaps between premaxillary teeth. Lower jaw fleshy, with numerous papillae on lip and gradually decreasing numbers of papillae continuing onto ventral portion of head as far as isthmus. Elements of infraorbital series reduced in width relative to other trans-Andean Creagrutus species other than C. maracaiboensis; ventral and posterior margins of series distinctly separated from preopercle, posteroventral margin of series rounded, and concentric with posteroventral margin of orbit.
Teeth arranged as in Creagrutus brevipinnis.
Dorsal fin with ii,8 rays. Dorsal fin origin slightly posterior to vertical through pelvic-fin origin. Distal margin of dorsal fin slightly concave centrally with anterior rays longest. Anal fin with ii, 10–12 rays. Anal fin of males with hooks on anterior one to four, typically three, branched rays; males with hooks usually on posterior branch but occasionally also on main anterior branch. Distal margin of anal fin nearly straight, with anterior rays slightly elongate in some specimens. Pectoral-fin length variable; reaching well posterior to pelvic-fin origin in some individuals. Pelvic fin with i,7, rarely 8, rays. Pelvic fin proportionally short relative to other species; relative length variable, occasionally reaching posteriorly beyond anal-fin origin; males with hooks on rays on all branched rays, males with hooks usually on both main branches of three or four medial rays, and medial ray with a medial and a lateral hook on most hooked segments.
Gill rakers 5–7 + 8–10 (14 specimens).
COLOR IN LIFE.—Schultz (1944b:337) reported the following life coloration for Creagrutus paralacus (identified by him as C. beni): “Specimen from the Río Chama at Estanques: Pelvic, pectoral, and adipose fins yellowish orange; front of anal fin orange; dorsal surface of eye red; area in front of eye yellow; central area of upper and lower caudal lobes bright red; back yellowish orange; lateral band and lower sides silvery, the lateral band is dark grayish or plumbeous in color on caudal peduncle; no caudal spot.” Schultz noted that a specimen from the Río Motatán, 4 km above Motatán, had “dorsal surface of eye orange; back yellowish; pelvics yellowish orange as is front of anal fin; central area of caudal lobes bright red, with yellowish color basally; lateral band grayish; dorsal and anal fins grayish distally; no caudal spot.”
COLOR IN ACOHOL.—Head with pattern of diffuse dark chromatophores on dorsal surface, most concentrated over fontanel and snout, with distinct but small crescent of dark pigmentation immediately in front of anterior nares. Continuous band of dark chromatophores extending posteroventrally from just anterior of nares posteriorly to anteroventral margin of orbit, becoming restricted to margin of orbit posteriorly and merging with diffuse pigmentation of dorsolateral surface of head. Second band of dark chromatophores extending laterally from snout across dorsal surface of premaxilla, maxilla, and portion of infraorbital series proximal to orbit. Dorsum of body with scattered small chromatophores more concentrated over centers of exposed portions of scales. Scales of dorsolateral surface of body with dark chromatophores concentrated along posterior margins, forming overall reticulate pattern. Region anterior of humeral mark diffusely pigmented. Humeral mark vertically elongate and tapering ventrally; chromatophores most concentrated dorsal of lateral line. Midlateral stripe formed largely by deep-lying, dark chromatophores, somewhat more diffuse ventral to dorsal fin, and partially masked by guanine in available specimens.
Caudal fin diffusely pigmented with some concentration of chromatophores on basal half of membranes of approximately central four rays. Central portion of branched anal-fin membranes darkly pigmented. Dorsal fin with dark chromatophores associated with unbranched rays. Dorsal fin membranes with dark chromatophores on all but basal one-quarter of membrane, forming an overall posteriorly tapering band. Lateral rays of pectoral fin with scattered dark chromatophores delimiting rays. Pelvic fins hyaline.
ETYMOLOGY.—The species name paralacus, from the Greek “para,” beside or near and the Latin “lacus,” meaning lake, referring to the distribution of the species in the rivers near Lago Maracaibo.
ECOLOGY.—All specimens with exact locality data were collected in high gradient streams in the mountains to the south and southeast of Lago Maracaibo. Schultz (1944a:178) described the type locality as “width of river bed up to 200 feet, but only a small flow of water among rubble bottom; current rapid; depth in a pool up to 2 feet.” The collecting site for samples of C. paralacus from the Río Cobre (USNM 121501) were described as “bottom large rubble to sand; current torrential,” comparable to the conditions described by Schultz (1944a) for the Río Gonzáles (USNM 121506), Río Chama (USNM 121503, 121506), Río Barregas (= Albarregas) (USNM 121499), and Río Motatán (USNM 121502).
DISTRIBUTION.—Southern and southeastern tributaries to Lago Maracaibo (Figure 7). Creagrutus paralacus was collected with C. hildebrandi at least in some localities in the Río Motatán system in the southeastern portion of the basin (compare Figures 7 and 13).
MATERIAL EXAMINED.—26 specimens.
HOLOTYPE.—VENEZUELA. Tachira: Río Catatumbo basin, Río Táchira, 7 km N of San Antonio, USNM 121504 (44.4).
PARATYPES.—VENEZUELA. Tachira: Río Catatumbo basin, Río Táchira, 7 km N of San Antonio, USNM 324379, 3 (32.3–53.6); MBUCV V-23300, 2 (39.8–44.0). Merida: Río Chama system, Río Albarregas (cited by Schultz, 1944b:336 as Río Barregas), just below Egido, USNM 121499, 10 (46.266.6); MBUCV V–23301, 10 (41.8–66.6).
NON-TYPE SPECIMENS EXAMINED.—861 specimens.
VENEZUELA. Tachira: Río Catatumbo basin, Río Cobre above its mouth in Río Quinta, tributary of Río La Grita, USNM 121501, 50. Río Catatumbo basin, Río Táchira, N of San Antonio, USNM 324380, 1 (juvenile collected with holotype). Río Motatán, 4 km above Motatán, USNM 121502, 25. Río Motatán, at bridge in Agua Viva, UF 25456,5. Mérida: Río Chama basin, Río Gonzáles at La Gonzáles, USNM 121506, 356. Río Chama, 10 km below Lagunillas, USNM 121506, 4. Rio Chama at Estanques, USNM 121503, 28. Río Chama system, Río Barregas, just below Egido, USNM 324378, 358 (formerly USNM 121499, in part). Río Chama, near Mérida, UMMZ 145388,24. Río Albirregas, near Mérida, CAS 69289, 2. Mérida, BMNH 1902.7.29:94–96, 3. Río Muyapas, Río Torondoy basin, 4.5 km S of Nueva Bolivia along Highway 1, INHS 60342, 4.
COLOMBIA. Norte de Santandar: Cucuta, La Silla, small brook, NRM 16855, 1.
The following lot was discussed above under “Remarks”: Creagrutus cf. paralacus, COLOMBIA. Cundinamarca: Sasaima, SE of Honda (4°58′N, 74°26′W), USNM 100738, 2 (1, 71.2).
- библиографски навод
- Harold, Antony S. and Vari, Richard P. 1994. "Systematics of the trans-Andean species of Creagrutus (Ostariophysi:Characiformes:Characidae)." Smithsonian Contributions to Zoology. 1-31. https://doi.org/10.5479/si.00810282.551
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