Simpsonichthys constanciae

Wilson J. E. M. Costa, 2007, Taxonomic revision of the seasonal South American killifish genus Simpsonichthys (Teleostei: Cyprinodontiformes: Aplocheiloidei: Rivulidae)., Zootaxa 1669, pp. 1-134 : 14-16

Simpsonichthys constanciae (Myers, 1942)

(Figs. 5-6)

Cynolebias constanciae Myers, 1942: 105 ( type locality: water hole for cattle, 10 miles N of Cabo Frio , State of Rio de Janeiro, Brazil [approximately 22°45’S 42°00’W; altitude about 4 m]; holotype: CAS (SU) 36514 ).

Material examined

Brazil: Estado do Rio de Janeiro: CAS (SU) 36514 , holotype, male, 36.0 mm SL; water hole for cattle, 10 miles N of Cabo Frio ; T. D. White, 12 May 1941 . MZUSP 36295 , 8; temporary pool near Barra de Sao Joao ; W. J. E. M. Costa, M. C. C. de Pinna, M. T. C. Lacerda & K. Tanizaki, 6 Jul. 1985 . MZUSP 38345 , 13; MZUSP, 38425 , 1 (c&s); same locality as MZUSP 36295 ; W. J. E. M. Costa & A. Peixoto, 27 Oct. 1984 . MZUSP 36300 , 8; same locality as MZUSP 36295 ; W. J. E.M. Costa, M. C. C. de Pinna, M. T. C. Lacerda, 23 Feb. 1985 . MZUSP 38337 , 5; same locality as MZUSP 36295 ; R. Lacorte & P. S. Santos, 2 Jul. 1978 . UFRJ 1851 , 6 (c&s); UFRJ 1978 , 3 (c&s); same locality as MZUSP 36295 ; W. J. E. M. Costa, C. P. Bove, M. Melgaco & F. Pitanga, 19 Nov. 1990 . UFRJ 2072 , 8; same locality as MZUSP 36295 ; W. J. E. M. Costa, M. Britto & A. Sarraf, 10 Jan. 1994 . UFRJ 2199 , 25; UFRJ 5809 , 2; UMMZ 230858 , 8; MCZ 138931 , 8; same locality as MZUSP 36295 ; W. J. E. M. Costa, M. Britto & R. Cunha, 1 Jun. 1994 . UFRJ 4757 , 6; temporary pool in Barra de Sao Joao ; W. J. E. M. Costa, C. P. Bove & B. B. Costa, 28 Nov. 1998 . UFRJ 6358 , 5; UFRJ 6359 , 5; same locality and collectors as UFRJ 4757 , 25 Jan. 2006 . UFRJ 2196 , 3; temporary pool near Rio das Ostras ; W. J. E. M. Costa, M. Britto & R. Cunha, 1 Jun. 1994 . UFRJ 5284 , 15; UFRJ 5285 , 4 (c&s); temporary pool between Barra de Sao Joao and Rio das Ostras ; W. J. E. M. Costa, 3 Feb. 2001 . MNRJ 15596 , 2; road Amaral Peixoto, km 150-152 ; E. Izecksohn, O. Peixoto & C. Cruz, 19 Aug. 1973 . MNRJ 19542 , 5; road Amaral Peixoto, km 150 ; C. Cruz, J. G. Silva & O. Peixoto, 4 Nov. 1973 .

Diagnosis

Distinguished from all other species of the subgenus in having all anal-fin rays unbranched (vs. some median rays branched), four longitudinal rows of rounded black spots on sides of body in males (vs. never a similar color pattern), long filamentous rays on tip of dorsal and anal fins in males, tip of longest dorsal and anal rays extending beyond posterior border of caudal fin (vs. filamentous rays short, never reaching posterior margin of caudal fin), dorsal-fin origin between neural spines of vertebrae 10 and 11 in males (vs. between neural spines of vertebrae 11 and 13), and absence of contact organs on flank and pectoral fin (vs. contact organs present in males).

Description

Morphometric data appear in Table 1. Largest specimen examined 41.5 mm SL. Dorsal profile slightly concave on head, convex from nape 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 deep, compressed, greatest body depth at level of pelvic-fin base. Eye positioned on lateral portion of head side. Snout blunt. Urogenital papilla cylindrical and short in males, pocket-shaped in females.

Tip of dorsal and anal fins pointed and long in males, rounded in females. Tip of dorsal and anal fins with long filamentous rays in males, tip of filaments reaching vertical behind posterior margin of caudal fin. Dorsal and anal-fin rays unbranched. Caudal fin rounded. Pectoral fins elliptical. Posterior margin of pectoral fins reaching vertical through base of 6th anal-fin ray in males and reaching urogenital papilla in females. Tip of pelvic fin reaching base of 4th anal-fin ray in males and base of 2nd anal-fin ray in females. Pelvic-fin bases medially in contact. Dorsal-fin origin on vertical through base of 6th or 7th anal-fin ray, between neural spines of vertebrae 10 and 11 in males, and neural spines of vertebrae 11 and 12 in females. Anal-fin origin between pleural ribs of vertebrae 7 and 8 in males and pleural ribs of vertebrae 8 and 9 in females. Dorsal-fin rays 16- 18 in males and 14-16 in females; anal-fin rays 22-25 in males and 21-23 in females; caudal-fin rays 22-23; pectoral-fin rays 11-12; pelvic-fin rays 6.

Frontal squamation E-patterned; E-scales overlapping medially; no scale anterior to H-scale. Supraorbital scales 2-3. Longitudinal series of scales 25-27; transverse series of scales 10-11; scale rows around caudal peduncle 12. Contact organs absent from flank and pectoral fins.

Cephalic neuromasts: supraorbital 7-8 + 6-7, parietal 2, anterior rostral usually absent, sometimes minute single neuromast, posterior rostral 1, infraorbital 2 + 24-30, preorbital 2-3, otic 2-3, post-otic 1-3, supratemporal1, median opercular 1, ventral opercular 1, preopercular 18-22, mandibular 10-12, lateral mandibular 3, paramandibular 1. One or two neuromasts on center of each scale of lateral line. Two neuromasts on caudalfin base.

Basihyal subtriangular, width about 35% of length; basihyal cartilage about 10% of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth 1-2. Gill-rakers on first branchial arch 2 + 11. Vomerine teeth absent. Dermosphenotic present. Ventral process of posttemporal short. Total vertebrae 26-28.

Coloration

Males. Side of body golden on anterior third of flank to light purplish brown on posterior portion; four horizontal rows of round black spots, sometimes horizontally coalescing, three dorsalmost rows along all extension of flank, ventral row between pectoral-fin base and middle of anal-fin base. Dorsum pale brown. Sides of head greenish golden, with purplish brown spots on opercular region. Iris yellow, with black bar through center of eye. Dorsal fin with pale blue spots alternating with dark gray spots, sometimes with golden iridescence; distal margin light blue; filaments black. Anal fin pale green, with dark gray spots, sometimes with golden iridescence; filaments black. Caudal fin with pale blue dots alternating with dark gray spots. Pectoral fins hyaline. Pelvic fins greenish yellow, with dark gray posterior border.

Females. Sides of body pale purplish brown, with 13-14 dark gray bars; usually one (sometimes two) black spots on anterocentral portion of flank, laterally bordered by pale blue vertical lines; belly orangish golden. Dorsum pale brown. Sides of head orangish brown; opercular region greenish golden. Iris yellow, with dark brown bar through center of eye. Dorsal and caudal fins hyaline, with faint rounded gray spots on basal portion. Anal fin orangish pink, with faint gray spots on basal portion. Pectoral and pelvic fins hyaline.

Distribution

Coastal plains adjacent to lower rio São João, Estado do Rio de Janeiro, southeastern Brazil (Fig. 4).

Habitat

Temporary pools in a semi-arid coastal areas, usually in places widely exposed to the sun.