Simpsonichthys suzarti, Wilson J. E. M. Costa, 2004

Wilson J. E. M. Costa, 2004, Simpsonichthys suzarti sp. n. (Teleostei: Cyprinodontiformes: Rivulidae): a new annual fish from the Rio Pardo floodplains, northeastern Brazil., Zootaxa 468, pp. 1-7 : 2-7

Simpsonichthys suzarti new species

(Figs. 1-2)

Holotype. MCP 34088 , male, 28.6 mm SL; Brazil: Estado da Bahia: temporary pool near Canavieiras, Rio Pardo floodplains (approximately 15°45’S 39°00’W; altitude about 4 m); D. B. Lara, 2002.

Paratypes. UFRJ 5810 , 1 female, 28.5 mm SL; UFRJ 5811 , 1 male, 28.9 mm SL, and 1 female, 24.7 mm SL (c&s); collected with holotype.

Diagnosis: Similar to S. constanciae , S. bokermanni , S. perpendicularis , and S. rosaceus , and distinguished from the remaining congeners by possessing eye laterally positioned on head (vs. dorsolaterally positioned), and anterior and posterior series of supraorbital neuromasts separated by interspace (vs. anterior and posterior series of supraorbital neuromasts continuous). Readily distinguished from S. constanciae , S. bokermanni , S. perpendicularis , and S. rosaceus by possessing rounded anal fin in males (vs. pointed), reddish brown bars alternated with bright greenish blue bars for the whole length of the flank of males (vs. restricted to anterior portion of flank in S. bokermanni , S. perpendicularis , and S. rosaceus , bars absent in S. constanciae ), dark brown reticulation on dorsal fin of male (vs. reticulated marks absent), and oblique dark brown bars on anal fin of male (vs. bars absent).

Description: Morphometric data given in Table 1. Male larger than female, largest male 28.9 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 moderately deep, compressed, depth about 1.5 times body width in larger males. Greatest body depth at level of pelvic-fin base. Caudal peduncle short, about half length of head.

Tip of dorsal fin slightly pointed in male, rounded in female. Tip of anal fin rounded in both sexes. Tip of dorsal and anal fins of male with short filamentous rays, tips reaching vertical through caudal-fin base. Dorsal-fin rays unbranched. Caudal fin round. Pectoral fin elliptical. Posterior margin of pectoral fin reaching vertical through base of 5th anal-fin ray in male, and through urogenital papilla in female. Tip of pelvic fin reaching base of 4th anal-fin ray in male and base of 2nd anal-fin ray in female. Pelvic-fin bases medially united. Dorsal-fin origin on vertical through base of 4th or 5th anal-fin ray in male, and through base of 6th anal-fin ray in female, between neural spines of vertebrae 11 and 12 in both sexes. Anal-fin origin between pleural ribs of vertebrae 7 and 8 in male, and pleural ribs of vertebrae 9 and 10 in female. Dorsal-fin rays 18-19 in male, 15-16 in female; analfin rays 22-24 in male, 22 in female; caudal-fin rays 22-23; pectoral-fin rays 11-12; pelvic-fin rays 6.

Scales large, cycloid. Body and head entirely scaled, except on ventral surface of head. Anal-fin base with few scales on its central portion. Frontal squamation E-patterned. Longitudinal series of scales 24-25; transverse series of scales 9; scale rows around caudal peduncle 12. One minute ctenii-like contact organ on each scale of anteroventral portion of lateral surface of body of male, usually inconspicuous. Small papillate contact organs on inner surface of three dorsalmost rays of pectoral fin of male. Supraorbital neuromasts 10- 12, anterior and posterior series separated.

Ventral process of angulo-articular moderate in width. Rostral cartilage narrow, width about 65 % of its length. Anterior and ventral edges of quadrate forming angle of about 100º. Posterior process of quadrate about 45 % of total ventral longitudinal length of quadrate. Lateral process of hyomandibula broad. Dorsal portion of metapterygoid wide, distal edge slightly expanded; ventral portion of metapterygoid narrow. Basihyal sub-triangular, longest width about 50 % of its total longitudinal length; basihyal cartilage about 25 % of total longitudinal length of basihyal. Six branchiostegal rays. Anterior portion of fifth ceratobranchial not elongated. One tooth on second pharyngobranchial. Gill-rakers on first branchial arch 3 + 11. Vomerine teeth absent. Small ossified dermosphenotic. Ventral process of posttemporal long. Total vertebrae 27.

Coloration: Male: Side of body light pink with 10-12 reddish brown bars alternated with bright greenish blue bars, and with light blue dots on dorsal portion. Opercular region pale greenish golden. Iris light yellow, with dark brown bar. Dorsal fin light blue with broad reddish brown reticulation. Anal fin yellow, with oblique brown bars. Caudal fin brownish red with light blue dots. Pectoral fin hyaline. Pelvic fin orange.

Female: Side of body brownish orange, with 10-12 gray bars; venter pale pink; 2-3 rounded black spots alternated with light blue narrow bars on anterocentral portion of flank. Opercular region pale greenish golden. Iris light yellow, with dark gray bar. Dorsal fin hyaline with faint gray spots; anal fin pink with gray spots; caudal fin hyaline; small pale blue spots on posterior portion of dorsal and anal fins, and on dorsal portion of caudal fin. Paired fins hyaline.

Distribution: Known only from the type locality, floodplains of lower rio Pardo, Estado da Bahia, northeastern Brazil (Fig. 3).

Etymology: The name suzarti in honor of Rogério Suzart, who sent me the type material of the new species.

Key to species of the S. constanciae group

1 No black spots on male flank; dorsal and anal fins of male with short filamentous rays, tip never reaching vertical through posterior margin of caudal fin; male with contact organs on flank scales and inner surface of upper pectoral-fin rays ............................ 2

- Four longitudinal rows of round black spots on male flank; dorsal and anal fins of male with long filamentous rays, tip posteriorly surpassing posterior margin of caudal fin; contact organs of flank and pectoral fin absent................................ S. constanciae

2 Anal fin pointed in male; bars restricted to anterior portion of male flank; no bars on male anal fin................................................................................................................. 3

- Anal fin rounded in male; reddish brown bars alternated with bright greenish blue bars on whole male flank; oblique brown bars on male anal fin............................ S. suzarti

3 No bright dots on caudal and anal fins of male.............................................................4

- White dots on dorsal fin and concentrated on dorsal half of male caudal fin................. ................................................................................................................. S. bokermanni

4 Three horizontal stripes on posterior half of male flank; 4 + 14 gill-rakers on first branchial arch; 16-18 dorsal-fin rays in female; male unpaired fins yellow.......................... ........................................................................................................... S. perpendicularis

- Usually no stripes, sometimes faint median stripe on posterior half of male flank; 3-4 + 11 gill-rakers on first branchial arch; 13-15 dorsal-fin rays in female; male unpaired fins red.......................................................................................................... S. rosaceus

Discussion

Simpsonichthys suzarti is a member of the S. constanciae species group , possessing the two apomorphic features diagnosing the group: supraorbital series of neuromasts interrupted by a median interspace and eyes laterally place on the head. In all other congeners and in all species of closely related genera (i. e., Austrolebias Costa , Cynolebias Steindachner , Megalebias Costa ), the supraorbital series of neuromasts is continuous and eyes are dorsolaterally placed on the head. However, relationships within this clade are unclear at the present. The presence of bars on the entire flank of males as occurring in S. suzarti is a plesiomorphic condition for cynolebiatines (e. g., Costa, 2001, 2002, 2003), possibly indicating a basal position of S. suzarti among species of the S. constanciae group .