Simpsonichthys myersi
Creators: name: Wilson J. E. M. Costa
Publisher: name: Zenodo
Year: 2007
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Cyprinodontiformes
Rivulidae
Simpsonichthys
Simpsonichthys myersi

description: Simpsonichthys myersi (Carvalho, 1971)
(Figs. 2-3)
Cynolebias myersi Carvalho, 1971: 401 (type locality: temporary pool along road between Conceição da Barra and Kaunas, 18 km from Conceição da Barra, Espírito Santo, Brazil [about 18°30’S 39°40’W]; holotype: MNRJ 9849).
Cynolebias izecksohni Cruz, 1983: 74 (type locality: Reserva Florestal da Companhia Vale do Rio Doce, Município de Linhares, Estado do Espírito Santo, Brazil [about 19°15’S 40°00’W]; holotype: MNRJ 10613).
Material examined
Brazil: Estado do Espírito Santo: rio Itaúnas basin: MNRJ 9849, holotype, male, 26.7 mm SL; MNRJ 9850, 1 paratype; MNRJ 9851, 53 paratypes; temporary pools along road between Conceição da Barra and Itaúnas, 18 km from Conceição da Barra; A. L. Carvalho, 9 Aug. 1969. UFRJ 4760, 31; UFRJ 4759, 6 (c&s); UFRJ 6353, 4 (c&s); 2 km N of Itaúnas; W. J. E. M. Costa, C. P. Bove, B. B. Costa, F. Pupo & L. Seca, 22 Dec. 1998. UFRJ 5237, 10; same locality as holotype; W. J. E. M. Costa, C. P. Bove & B. B. Costa, 7 Jan. 2001. Rio Barra Seca basin: MNRJ 10613, holotype of C. izecksohni, male, 27.5 mm SL; MNRJ 10614 1 paratype of C. izecksohni; MNRJ 10615, 2 paratypes of C. izecksohni; MZUSP 14721-14724, 4 paratypes of C. izecksohni; Reserva Florestal da Companhia Vale do Rio Doce, Linhares; C. A. G. Cruz, J. F. Pinheiro & S. P. C. Silva, 18 Jan. 1980. UFRJ 5236, 6; UFRJ 5812, 5 (c&s); same locality; W. J. E. M. Costa, C. P. Bove & B. B. Costa, 6 Jan. 2001. Rio São Mateus basin: MZUSP 38336, 3; Conceição da Barra; V. Teixeira & J. C. Ghisolfi, 1986. UFRJ 5056, 25; UFRJ 5057, 2; UFRJ 5255, 4; UFRJ 5813, 2 (c&s); temporary pool close to Conceição da Barra; W. J. E. M. Costa, 2 Jan. 2000. UFRJ 4761, 4; same locality as UFRJ 5056; W. J. E. M. Costa, C. P. Bove, F. Pupo & L. Seca, 22 Dec. 1998. UFRJ 5290, 2; same locality as UFRJ 5056; W. J. E. M. Costa, C. P. Bove & B. B. Costa, Jan. 2001. UFRJ 6357, 17; same locality as UFRJ 5056; W. J. E. M. Costa, B. B. Costa & C. P. Bove, 11 Jan. 2006. Estado da Bahia, rio Mucuri basin: UFRJ 249, 20; UFRJ 282, 1 (c&s); UFRJ 3161, 3 (c&s); UMMZ 231549, 4; MCZ 138936, 4; temporary pool 1 km N of Mucuri; G. C. Brasil, Sep. 1989. UFRJ 377, 2; Mucuri; W. J. E. M. Costa, C. P. Bove, M. Melgaço & F. Pitanga, 14 Nov. 1990. UFRJ 4762, 17; UFRJ 5814, 4 (c&s); swamp 5 km W of Mucuri; W. J. E. M. Costa, C. P. Bove, B. B. Costa, F. Pupo & L. Seca, 22 Dec. 1998. UFRJ 6355, 22; UFRJ 6356, 4 (c&s); pools within forest, about 5 km W of Mucuri; W. J. E. M. Costa, B. B. Costa & C. P. Bove, 13 Jan. 2006. Rio Itanhém basin: UFRJ 250, 12; temporary pool 10 km N of Caravelas; G. C. Brasil, Sept. 1989. UFRJ 4764, 7; swamp about 7 km W of Alcobaça; W. J. E. M. Costa, C. P. Bove, B. B. Costa, F. Pupo & L. Seca, 25 Dec. 1998. Rio Jucuruçu basin: UFRJ 1921, 1; UFRJ 5815, 4 (c&s); temporary pool 1 km N of Prado; W. J. E. M. Costa & C. P. Bove, 19 Jun. 1993. UFRJ 5288, 4; same locality as UFRJ 1921; W. J. E. M. Costa, C. P. Bove & B. B. Costa, 21 Jan. 2001. UFRJ 6063, 21; UFRJ 6354, 4 (c&s); same locality as UFRJ 1921; W. J. E. M. Costa, C. P. Bove & B. B. Costa, 4 Jan. 2005.
Diagnosis
As for the subgenus.
Description
Morphometric data appear in Table 1. Largest specimen examined 36.5 mm SL. Dorsal profile convex from snout to end of dorsal-fin base, approximately straight on caudal peduncle. Ventral profile convex from lower jaw to end of anal-fin base, nearly straight on caudal peduncle. Body moderately slender and compressed, greatest body depth at level of pelvic-fin base. Eye positioned on dorsal portion of side of head. Snout blunt or sometimes slightly pointed in larger males. Urogenital papilla cylindrical and short in males, pocket-shaped in females.
Tip of dorsal fin pointed in males, with long filament reaching vertical through posterior portion of caudal fin; dorsal fin rounded to slightly pointed in females. Tip of anal fin pointed in males, with long filament reaching vertical through middle of caudal fin; anal fin rounded in females, with short filaments on posterior margin. Most dorsal and anal-fin rays branched, rays at tip of fin unbranched. Caudal fin lanceolate, ventral portion weakly expanded, resulting in an asymmetrical shape. Pectoral fins elliptical to pointed. Posterior margin of each pectoral fin reaching vertical between base of 6th and 8th anal-fin ray in males, and reaching urogenital papilla in females. Tip of each pelvic fin reaching base of 3rd or 4th anal-fin ray in males and base of 2nd or 3rd anal-fin ray in females. Pelvic-fin bases medially united. Dorsal-fin origin on vertical between base of 7th and 9th anal-fin ray, between neural spines of vertebrae 11 and 14 in males and neural spines of vertebrae 13 and 16 in females. Anal-fin origin between pleural ribs of vertebrae 8 and 10 in males and pleural ribs of vertebrae 9 and 12 in females. Dorsal-fin rays 15-18 in males, 12-16 in females; anal-fin rays 20-24 in males, 19-22 in females; caudal-fin rays 24-28; pectoral-fin rays 13-14; pelvic-fin rays 6.
Frontal squamation E-patterned; E-scales medially overlapped; no scale anterior to H-scale. Two small supraorbital scales. Longitudinal series of scales 26-28; transverse series of scales 9-10; scale rows around caudal peduncle 12-14. Contact organ on each scale of ventral portion of flank in males. Minute papillate contact organs on inner surface of two dorsalmost rays of pectoral-fin in males.
Cephalic neuromasts: supraorbital 10-12, parietal 1-3, anterior rostral 1, posterior rostral 1, infraorbital 2 + 14-18, preorbital 3, otic 1, post-otic 2, supratemporal 1, median opercular 1, ventral opercular 1-2, preopercular11-14, mandibular 8-12, lateral mandibular 3-7, paramandibular 1. One neuromast on center of each scale of lateral line. Two neuromasts on caudal-fin base.
Basihyal subtriangular, width about 55-75% of length; basihyal cartilage about 35% of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth absent. Gill-rakers on first branchial arch 3 + 10-11. Vomerine teeth absent. Dermosphenotic present. Ventral process of posttemporal long. Total vertebrae27-29.
Coloration
Males. Sides of body light brownish yellow to light greenish blue, with 10-15 dark crimson to dark brown bars, sometimes almost black. Dorsum light brown. Venter yellowish gray. Head side golden, with three dark brown bars, anterior bar adjacent to posterior margin of orbit, middle bar on preopercle, posterior bar between preopercle and posterior edge of opercle; short dark brown infraorbital bar. Iris light yellow to orangish yellow, with reddish brown bar through center of eye. Dorsal fin dark brownish red to dark brown with 5-8 pale yellow to light blue bars on basal portion, often pale yellow to light blue small round spots on distal half of fin; dorsal-fin filaments orange to brown. Anal fin dark brown to dark red, with 6-8 pale yellow to light blue bars, dorsal portion of bar just posterior to end of anal-fin base white; often small pale blue or yellow round spots on distal portion of fin; anal-fin filaments orange. Caudal fin pale yellow to light blue, with 4-9 dark red to dark brown bars, sometimes branched; caudal fin margin dark reddish brown, united to posteriormost bar of caudal peduncle. Pectoral fins hyaline. Pelvic fins dark reddish brown, with pale yellow margin.
Females. Sides of body pale brown with 9-12 broad dark brownish gray bars; 1-3 vertically elongated to round black blotches on anterocentral part of flank; often 1-3 small dark gray to black spots on posterior part of caudal peduncle. Dorsum pale brown. Venter light gray. Side of head pale brown with small dark brown spots; golden iridescence on opercular region. Iris yellow with brown bar through center of eye. Dorsal and anal fins hyaline with elongated dark gray spots on basal portion of fin; caudal fin hyaline with small dark gray spots on basal portion. Paired fins hyaline.
Distribution
As for the subgenus.
Habitat
Temporary pools in the Restinga and border of the Atlantic forest.
Remarks
The exhaustive comparison among morphological features of all known populations belonging to the subgenus Xenurolebias indicated that the two included nominal species (myersi and izecksohni) cannot be distinguished.
description: Published as part of Wilson J. E. M. Costa, 2007, Taxonomic revision of the seasonal South American killifish genus Simpsonichthys (Teleostei: Cyprinodontiformes: Aplocheiloidei: Rivulidae)., pp. 1-134 in Zootaxa 1669 on pages 8-12