Cynopoecilus melanotaenia (Regan)

M., Wilson J. E., 2002, The annual fish genus Cynopoecilus (Cyprinodontiformes: Rivulidae): taxonomic revision, with descriptions of four new species, Ichthyol Explor. Freshwaters 13, No. 1, pp. 11-24 : 13-16

Cynopoecilus melanotaenia (Regan) (Fig- 2)

Cynolebias melanotaenia Regan, 1912a: 506 (original description, Paranagua [Estado do Paraná], southeastern Brazil [corrected to "vicinity of Quinta Station" [about 32°10’S 52°20’W] by May­er, 1952: 114-115]).

Material examined. Brazil: Rio Grande do Sul: UFRJ 5033, 105 ex.; road to Cassino, 6 km before city ; W. J. E. M. Costa & A. C. Bacellar, 5 Sept 1999 . - UFRJ 4837 , 14 ex .; UFRJ 5225 , 4 ex. (c&s); Estação Quinta, road BR-471 ; W. J. E. M. Costa, D. Belote, D. Almeida & F. Pupo, Jul1998 . - UFRJ 4979 , 40 ex .; UFRJ 5019 , 3 ex (c&s); 15.5 km S of Pelotas; W. J, E. M. Costa & A. C. Bacellar, 10 Sept1 999 . - UFRJ 4010, 18 ex.; Pontal da Barra , Pelotas; M. Cheffe & G. Mauricio, 15 Oct 1995 . - UFRJ 4981 , 26 ex.; road to Cassino, 5 km before city ; W. J. E. M. Costa & A. C. Bacellar, 6 Sept 1999 . - UFRJ 4008 . 26 ex .; UFRJ 5228 , 5 ex. (c&s); Pontal da Barra , Pelotas; M. Cheffe & G. Mauricio, 7 Sept 1993 . - UFRJ 5058 , 16 ex.; road BR- 471,1 km N of Estação Ecológica do Taim ; W. J. E. M. Costa & A. C. Bacellar, 14 Sept 1999 . - UFRJ 4947 , 50 ex .; UFRJ 5223 , 8 ex. (c&s); road BR-471,8.5 km S of Estação Ecológica do Taim ; W. J. E. M. Costa & A. C. Bacellar, 4 Sept 1999 . - UFRJ 4980 , 13 ex.; Estação Quinta , road BR-392 ; W. J. E. M. Costa & A. C Bacellar, 6 Sept 1999 . - UFRJ 4951, 5 ex,; pool close to arroio Chui , road to Barra do Chuí; W. J. E. M. Costa & A. C. Bacellar, 6 Sept 1999 . - UFRJ 4009, 22 ex.; Pontal da Barra , Pelotas; M. Cheffe & G. Maurido, 16 Aug 1993 . - UFRJ 4827 , 28 ex .; UFRJ 5226 , 6 ex. (c&s); Pontal da Barra , Pelotas; W. J. E. M. Costa, D. Belote, D. Almeida & F. Pupo, 20 Jul 1998 . - UFRJ 4823, 59 ex .; UFRJ 5227, 8 ex. (c&s); pool between Chui and Barra do Chuí ; W. J. E. M. Costa, D. Belote, D. Almeida & F. Pupo, 19 Jul 1998 . - UFRJ 4498 , 81 ex .; UFRJ 5224, 7 ex. (c&s); road BR-116 , 12.5 km S of Cristal; W. J. E. M. Costa, D. Belote & R. D'Arrigo, 14 Sept 1997 . - UFRJ 4487 , 32 ex .; UFRJ 4491, 4 ex. (c&s); road BR- 116, 9 km SW of Camaquã; W. J. E. M. Costa, D. Belote & R. D' Arrigo, 14 Sept 1997 .

Uruguay: Departamento de Rocha: MNRJ 19427, 4 ex.; swamp on road to Barra de Valizas ; L. H. Amato, 10 Jan 1981 .

Diagnosis. Differs from all its congeners and species of closely related genera ( Campellolebias , Cynopoecilus ) by a reduced pigmentation pattern of caudal fin of male (faint spots restricted to the dorsal portion of the fin or caudal spots absent, vs. the whole caudal fin with dark spots). It is also distinguished from all other species of the genus by the combination of the following characters: pectoral-fin length of male 18.6-22.6 % SL (vs. 16.1- 185 in C. fulgens ), longitudinal rows of spots on body of male pale golden to greenish golden anteriorly and light blue posteriorly (vs. all spots bright golden in C. fulgens ), pelvic-fin length 6.8-83 % SL in male, and 6.4-7.5 in female (vs. 4.7-5.6 in male and 4.1-5.3 in female of C. intimus ), dark brown irregular marks on dorsum below dorsal fin of male (vs. rounded blotches in C. intimus ), dorsal profile of head of adult male slightly concave (vs. strongly concave in C. nigrovittatus ), lateral body stripes of male dark reddish brown (vs. black in C. nigrmittatus), caudal fin of male without a bright blue zone along posterior margin of the fin (vs. present in C. nigrovittatus ), 11 - 14 supraorbital neuromasts (vs. 17- 20 in C. multipapillatus ), and one to three neuromasts per scale of the lateral line (vs. five to nine in C. multipapillatus ).

Description. Morphometric data are given in Tables 1 and 2. Body slender, slightly compressed, body width approximately 1.5 in body depth in larger males. Longest body depth on a vertical through pelvic-fin base. Dorsal profile nearly straight to slightly concave on head, convex between nape and posterior end of dorsal-fin base, approximately straight on caudal peduncle; ventral profile between lower jaw and end of anal-fin base smoothly convex to approximately straight in male, convex in female, and approximately straight on caudal peduncle of both sexes.

Tip of dorsal and anal fins pointed and long in male, rounded and short in female. Caudal fin rounded to subtruncate. Pectoral fin elliptical. Posterior margin of pectoral fin just posterior to a vertical through pelvic-fin base in male, and just anterior to that vertical in female. Tip of pelvic fin reaching base of genital bulb. Pelvic fins separated by a small interspace. Dorsal-fin origin in a vertical through genital bulb in male, and through anus in female. Anal-fin origin in a vertical through base of 2nd or 3rd dorsal-fin ray in male, and base of 4lh or 5th in female. Dorsal-fin rays 16-19; anal-fin rays 22-25; caudal-fin rays 27-30; pectoral-fin rays 12- 13; pelvic-fin rays 5-7. Longitudinal series of scales 25-27, transverse series of scales 8-9, and scale rows around caudal peduncle 12. Ctenii-like contact organs on caudal peduncle side of male. No contact organs on pectoral-fin of male. Supraorbital neuromasts 11- 14. One to three neuromasts per scale of lateral line. Gill-rakers on first branchial arch 2 + 9. Total vertebrae 28-30.

Coloration. Male: side of body light yellowish brown; a broad, dark reddish brown horizontal stripe on midline of body and head, between lower jaw and caudal-fin base; on body side and opercular region stripe overlapped by longitudinal series of spots, pale golden to greenish golden anteriorly and light blue posteriorly, each spot on center of each scale; a narrower reddish brown stripe, slightly lighter and ventral to median stripe, between pectoral-fin base and end of anal-fin base, anteriorly overlapped by small pale golden spots; dark reddish brown pigment concentrated on posterior borders of dorso-lateral scales, forming a longitudinal row of irregular marks. Dor ­ sum light brown with small rounded dark reddish brown spots. Venter white. Suborbital bar dark reddish brown, usually posteriorly followed by similar; lighter marks. Iris yellow, with a ver ­ tical dark brownish red bar; dark reddish brown pigment concentrated on posterior portion of iris. Unpaired fins pale reddish brown; small dark reddish brown spots on dorsal fin; faint similar spots sometimes on dorsobasal portion of caudal fin, sometimes absent, and posterobasal portion of anal fin. Pectoral fin hyaline. Pelvic fin brownish gray.

Female: color pattern as in male, but lateral longitudinal stripes light brownish gray, overlapped by a few longitudinal series of bright greenish golden small spots on center of each scale, and unpaired fins hyaline with faint gray small spots.

Distribution. Stream floodplains along inner edge of lagoa dos Patos and coastal floodplains on the outer edge of lagoa Mirim, southern Brazil and eastern Uruguay ( Fig. 1 ).

Figures

Fig. 1. Geographic distribution of Cynopoecilus: C. melanotaenia (*), C.fulgens (■), C. infimus (*), C. nigrovittatus (♦), and C multipapillatus (*}. Arrows indicate type localities; symbols may represent more than one locality. Scale bar 70 km.