Simpsonichthys lopesi, Nielsen, Dalton Tavares Bressane, Shibatta, Oscar Akio, Suzart, Rogério Dos Reis & Martín, Amer Faour, 2010

Nielsen, Dalton Tavares Bressane, Shibatta, Oscar Akio, Suzart, Rogério Dos Reis & Martín, Amer Faour, 2010, A new species of Simpsonichthys (Cyprinodontiformes: Rivulidae) from the rio São Francisco basin, northeastern Brazil, Zootaxa 2452, pp. 51-58 : 52-56

Simpsonichthys lopesi , new species

(Figs. 1–3; Table 1 )

Holotype. MZUSP 103102, male 33.3mm SL, City of Muquém de São Francisco, locality of Javi, temporary pool near the riacho de Santana, rio São Francisco basin, 12o12'04.6"S, 43o39'27.8"W, 20.iii.2008. Col. Rogério dos Reis Suzart, Amer Faour Martín, Walber Stepple Hiluey.

Paratypes. MZUSP 103103, 2 males (45.8– 31.7mm SL), 3 females (31.6– 22.3mm SL), same data from holotype. MZUEL 5177, 5 males (41.0– 23.1mm SL, 2 C&S), 8 females (34.5– 17.8mm SL, 2 C&S), same data from holotype.

Diagnosis: Simpsonichthys lopesi differs from remaining congeneric species, except S. multiradiatus and S. adornatus , because of the elongated dorsal fin base length of males that begins well anterior to the vertical line through the middle of the body, before pelvic fin origin. Simpsonichthys lopesi differs from S. multiradiatus by the color pattern of its body and anal fin without transverse stripes (vs. with red transverse stripes). Simpsonichthys lopesi differs from S. adornatus by the variable color pattern of its anal fin, with males presenting yellow and dark stripes or dark color with unlined yellow spots (vs. small blue spots). Males of S. lopesi generally have a lower number of rays on the dorsal fin compared to males of S. adornatus (22–30 vs. 28–32), higher predorsal length (34.3–38.8% SL vs. 28.3–34.4%), higher dorsal–fin base length (45.9– 53.7% SL vs. 54.0–60.3%), lower anal fin base length (36.3–41.7% SL vs. 43.4–48.2%), lower head depth (75.9–98.5% HL vs. 106.8–113.8%), and bigger snout length (19.2–27.0% HL vs. 11.4–14.6%). Females of S. lopesi differ from females of S. adornatus by having a lower body depth (22.1–32.7% SL vs. 34.3–36.8%), lower caudal peduncle depth (11.2–14.3 vs. 14.1–15.2), lower head depth (77.5–97.9% HL vs. 98.3–108.9), lower head (57.3–72.3% HL vs. 73.7–78.2%), and bigger snout length (17.9–20.9% HL vs. 12.3–14.9%).

Description. Morphometric data are presented in Table 1 . Largest specimen examined 45.8mm SL. Body relatively high. Dorsal profile convex from snout to end of dorsal fin base, slightly concave or 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. Eyes positioned on dorsal portion of side of head. Snout blunt. Urogenital papilla cylindrical and short in males, pocket-shaped in females.

Tip of dorsal fin pointed in old males and rounded in young; rounded in females; tip of anal fin rounded in both sexes. Short filamentous ray on tip of dorsal fin in males, reaching vertical through base of caudal fin; filaments absent in anal fin. Dorsal fin rays unbranched except in one male and two females with two branched rays under the filamentous ray on tip of dorsal fin. Caudal fin rounded. Pectoral fins elliptical. Posterior margin of each pectoral fin reaching vertical through base of first, second or fourth anal-fin rays in males, and between pelvic fin and urogenital papilla in females. Tip of each pelvic fin reaching base of first or second anal-fin ray in males and base of first anal fin ray in females. Pelvic fin bases in close proximity. Dorsal fin origin previous to pelvic fin origin in males, anal fin origin on vertical through base of third dorsal fin ray; dorsal fin origin posterior to anal fin origin in females, on vertical through base of third and fifth anal fin ray; one female with dorsal fin origin anterior to anal fin. Dorsal fin origin between neural spines of vertebrae 3 and 5 in males, and neural spines of vertebrae 10 and 12 in females. Anal fin origin between pleural ribs of vertebrae 6 and 8 in males, and pleural ribs of vertebrae 8 and 10 in females. Dorsal fin rays 22(1), 25(2)*, 26(1), 27(1), 28(1) and 30(1) in males, 11(1), 15(4), 16(5) and 17(1) in females; anal fin rays 21(3) and 22(5)* in males, 18(1), 19(6), 20(3) and 21(1) in females; caudal fin 20(1), 21(6)*, 22(4), 23(1), 24(7) and 25(1); pectoral fin rays 10(1), 11(9), 12(8)* and 13(1); pelvic fin rays 4(3), 5(8) and 6(6)*.

Males (n=8) Females (n=11)

Holotype Low-high Mean ± SD Low-high Mean ± SD Frontal squamation E-patterned; E-scales overlapping medially; no row of scales anterior to G-scale; supraorbital scales 2. Longitudinal series of scales 25(2), 26(5), 27(5) and 28(6)*; transverse series of scales 10(6), 11(10) and 12(2)*; scale rows around caudal peduncle 10(3), 11(5), 12(9) and 13(1)*. Contact organ on each scale of flank and ventral portion of opercle in males. Small papillae contact organ on inner surface of three dorsalmost rays of pectoral fins in males.

Basihyal sub triangle, its width about 50% of length; basihyal cartilage about 25% of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth 3–4. Gill-rakers on first branchial arch 2+7. Vomerine teeth absent. Dermosphenotic absent. Ventral process of postemporal long. Total vertebrae 26(1) and 28(3).

Coloration in life. Males (Figs. 1 and 2). The color pattern of the trunk in newly collected specimens is yellowish white, slightly red. Head with dorsal and pre-dorsal areas reddish-yellow. Opercular area light yellow with an iridescent blue reflex. Black transversal stripe crossing eyes vertically. About three series of iridescent blue spots lined on flank. Dorsal-fin with yellow base becoming dark brown posteriorly. Oblique light yellow stripes on anterior dorsal-fin area that continuous as spots posteriorly; about 8 to 10 series of stripes and spots lined obliquely. Anal-fin color golden-yellow, with a lighter base, either followed by two yellow stripes or lined with light spots, with dark stripes in between. Caudal-fin golden yellow from base to its center, where it becomes transparent. Dorsal and pelvic fins hyaline and slightly dark posteriorly.

FIGURE 1. Simpsonichthys lopesi , holotype, MZUSP 103102, male, 33.3mm SL, Bahia, Muquém do São Francisco, temporary pool close to riacho de Santana (12o12'4.6"S 43o39'27.8"W), rio São Francisco basin.

Two different color patterns of male anal fin are evident in newly collected specimens, and become even more evident in specimens maintained in aquarium: one with stripes and another with spots. Even smaller adults already present the anal fin stripe or spot pattern well defined. Besides the difference in anal fin color pattern, other differences were identified.

Striped form (Fig. 1): Dark blue trunk with white ventral area. Dorsal scales lightly red at the end, from snout to base of caudal fin. Several lines of iridescent blue on the dorsal area, from eyes to caudal fin base. A line of iridescent blue spots begins near dorsal fin base and extends to caudal fin, where the spots get progressively larger. Another line is composed of eight irregular iridescent blue spots, parallel to the first line, beginning near the vertical line that crosses the end of the dorsal fin and extends to the caudal fin base. More ventrally, a third line with smaller light and hardly noticeable spots is present. Dorsal fin with variable ground color, from reddish to golden, with yellow spots. Near the dorsal-fin base spots are larger and decrease when approaching the dorsal fin outline. Three light spots on the first rays of dorsal fin are present, starting on the fin base and spreading out towards the top with small spots on the higher part of the fin. Caudal fin with same pattern, but with less intense background body color. Two lines of red to golden small spots are present. Posteriorly on fins there are fine blue lines that are hardly noticeable. Pelvic fin light orange, more intense near base. Anal fin with five light and dark stripes. The external stripe is slender and almost black, becoming gray closer to edge. There is also a fine light yellow stripe, followed by a dark, almost black stripe and another light yellow stripe. The stripe nearest fin base is dark, but not as intense as the one located between the two light stripes. At the end of the intermediate light stripe there is a single, small iridescent light spot. There is an intermediate anal fin color pattern, with the proximal light stripe broken in elongated blotches and the distal stripe formed by small spots closely placed.

Painted form ( Fig. 2 ): Dark blue body, with various lines of shiny scales on dorsal area, beginning near eyes and ending on caudal fin. Dorsal fin golden red with different sizes of scattered spots. Four shining light blue stripes on the first rays of dorsal fin, beginning near the base and ending dorsally. Anal fin reddish yellow on first rays near base, black on posterior rays, and outlined with three lines of light blue circular or oval spots. The first line of spots, nearest the base, presents about seven bigger spots arranged in a line. The second line is placed under the first line, presents about ten spots of various sizes, but these always smaller then the first line. The third line, closer to the fin, presents a group of smaller spots.

Female ( Fig. 3 ): Body sides light purplish gray, golden on ventral area, with horizontal line of small dark brownish gray spots, sometimes coalesced to form horizontal stripes; spots on anterocentral portion of flanks black. Two black elliptical spots on the base of caudal fin, vertically arranged, with lighter margins. Two round black blotches, vertically arranged, on posterior portion of caudal peduncle. Iris light yellow, with dark gray stripe through center of eye. Opercular area light blue, with small gray spot. Dorsal and anal fins hyaline, with small dark brownish gray spots on membrane between the rays, and in continuity with the body. Pectoral and pelvic fins hyaline. Hyaline caudal fin with or without small dark spots on base. Some females present a black circular spot perfectly defined on middle of trunk.

Distribution. Known only from the type-locality in rio São Francisco basin, Bahia, Brazil.

Habitat ( Fig. 4 ). The pool where specimens were collected from is located in a stream of the Santana basin that supplies the city of Muquém, on a left bank depression of the São Francisco river, near the mountains of the Espinhaço plateau, in an area of swamps and aluvial terraces. The pool was oval, with 20m in length and 10m in width, and was used as a water supply for cattle. The substrate was clay, which rendered the water turbid. The water temperature at surface was approximately 29ºC and, in the deepest portion and banks, approximately 22ºC. The annual average temperature of the region is 24ºC, with maximum of 30.8ºC and minimum of 20.1ºC. The water pH was 7.2, slightly alkaline, as result of calcareous aluvial depositions. Average depth of water column was 40cm, with deepest portions about 60cm. The region has annual average rainfall of 800 to 900mm, and a rainy season from November to March. The marginal vegetation is typically of the Caatinga biome, about 2m in height, that supplied a shady area where the fishes were easily found. The aquatic vegetation was composed essentially of Echinodorus sp. and Nymphea sp. The left slide of the pool was artificially extended about 60m and reached a depth of more than 2m, but the vegetation was scarce and few specimens of S. lopesi were captured. Sympatric with S. lopesi were the rivulids S. flagellatus and Cynolebias gibbus . This was also noticed by Nielsen (2008) who observed sympatry among species of Hypsolebias and Cynolebias in other pools, with species of Cynolebias foraging on species of Hypsolebias .

Behavior in captivity. Males active during the day, especially for feeding, reproduction and territorial defense. Those males that displayed very quick swimming movements were more aggressive, especially with females. When two males were maintained together one may die victim of the other. Fishes newly collected from the pool present a body color similar to the water, in yellowish white, that changes in captivity, presenting a color similar to S. igneus (reddish yellow), but with a greenish blue reflex, just like in S. adornatus . During courtship of females, the abdominal area becomes white in males and the rest of the body dark blue with light iridescent spots.

Etymology. The name lopesi is in honor of Edson Lopes, because of his contribution to our knowledge on raising and breeding annual fishes in captivity.

Figures

FIGURE 2. Male of Simpsonichthys lopesi, spotted form, not preserved, from same locality of holotype.

FIGURE 3. Simpsonichthys lopesi, female, not preserved, from same locality of holotype.

FIGURE 4. Type locality of Simpsonichthys lopesi near riacho de Santana, São Francisco river basin.

Tables

TABLE 1. Morphometric data of Simpsonichthys lopesi. Low and high measurements include holotype.

Standard length (mm)	33.3	22.6–45.8	30.9 ± 8.7	16.6–34.5	24.67.0
Percents of SL
Body depth	32.9	31.0–33.7	32.5 ± 1.0	22.1–32.7	29.7 ± 3.9
Caudal peduncle depth	13.2	12.9–14.3	13.7 ± 0.5	11.2–14.3	13.1 ± 0.9
Pre-dorsal length	34.3	34.3–38.8	36.3 ± 1.9	55.6–63.5	60.1 ± 2.1
Pre-pelvic length	41.5	38.6–46.6	42.0 ± 2.7	44.1–52.9	47.52.9
Length of dorsal-fin base	51.0	45.9–53.7	51.0 ± 2.4	18.7–30.3	24.9 ± 3.1
Length of anal-fin base	39.5	36.3–41.7	39.5 ± 1.8	21.7–29.5	26.1 ± 2.8
Caudal-fin length	24.3	24.3–31.8	27.2 ± 2.7	20.4–32.1	27.3 ± 3.5
Pectoral-fin length	20.4	19.5–24.9	22.3 ± 1.8	14.1–24.2	20.5 ± 3.3
Pelvic-fin length	8.0	6.7–9.4	8.2 ± 0.8	7.2–10.3	8.6 ± 0.9
Head length	24.7	24.7–27.3	26.3 ± 0.8	25.1–30.0	27.2 ± 1.2
Percents of HL
Head depth	92.6	75.9–98.5	89.6 ± 7.5	77.5–97.9	86.6 ± 5.8
Head width	69.6	60.5–72.2	66.1 ± 3.8	57.3–72.3	63.3 ± 5.5
Snout length	27.0	19.2–27.0	22.3 ± 2.7	17.9–20.9	19.6 ± 1.0
Lower jaw length	27.7	21.2–28.5	25.2 ± 2.7	19.3–28.2	22.4 ± 2.6
Eye diameter	32.7	28.2–34.3	31.6 ± 2.0	27.4–34.0	31.7 ± 2.0