Pituna brevirostrata, Costa, Wilson J. E. M., 2007

Costa, Wilson J. E. M., 2007, Taxonomy of the plesiolebiasine killifish genera Pituna, Plesiolebias and Maratecoara (Teleostei: Cyprinodontiformes: Rivulidae), with descriptions of nine new species, Zootaxa 1410, pp. 1-41 : 6-9

Pituna brevirostrata , new species

( Figs. 2–3 )

Material examined. Holotype: UFRJ 6427 (male, 24.2 mm SL); Brazil: Estado de Goiás: Goiânia, rio Meia Ponte floodplains, rio Paranaíba drainage, rio Paraná basin, 16°38’29.8”S, 49°15’28.4”W, altitude about 750 m; F. O. Pereira, R. S. Roque & L. A. Costa Filho, 22 June 2006.

Paratypes: Brazil: Estado de Goiás. UFRJ 6428 (3 males, 17.5–21.5 mm SL; 3 females, 21.4–27.6 mm SL); UFRJ 6429 (2 males, 20.7–26.2 mm SL; 3 females, 23.0– 25.3 mm SL) (c&s); MCP 40496 (1 male, 21.1 mm SL; 1 female, 21.4 mm SL); all paraypes collected with holotype.

Diagnosis. Pituna brevirostrata is distinguished from all congeners by the following unique features: 23– 24 scales in longitudinal series (vs. 25–29), pectoral fin without dark marks (vs. with vertical rows of small dark gray spots or dark gray bars in males), frontal squamation D-patterned (vs. F-patterned), anterior section of supraorbital series of neuromasts interrupted (vs. continuous) and 25 vertebrae (vs. 27–29).

(continued).

(continued).

Description. Morphometric data appear in Table 1 . Largest male examined 26.2 mm SL; largest female examined 27.6 mm SL. Dorsal profile slightly convex from snout to end of dorsal-fin base, approximately straight to slightly concave on caudal peduncle. Ventral profile gently convex from lower jaw to anal-fin origin, nearly straight along caudal peduncle. Body slender, subcylindrical, slightly deeper than wide, greatest body depth at level of pelvic-fin base. Jaws short, snout blunt.

Dorsal and anal fins pointed in both sexes, longer and often with filamentous tip reaching to vertical through base of caudal fin in males. Caudal fin rounded. Pectoral fin rounded, its posterior margin reaching vertical between pelvic-fin base and anus in males, through pelvic-fin base in females. Pelvic fin short, slightly pointed in males, elliptical in females; tip of pelvic fin reaching between base of 1st to 4th anal-fin rays in males, and between urogenital papilla and base of 1st anal-fin ray in females. Pelvic-fin bases medially in close proximity. Dorsal-fin origin at vertical through base of 8th or 9th anal-fin rays, between neural spines of vertebrae 14 and 15. Anal-fin origin between pleural ribs of vertebrae 11 and 13. Dorsal-fin rays 10–11; analfin rays 14–16; caudal-fin rays 24–25; pectoral-fin rays 15; pelvic-fin rays 7.

Scales large, cycloid. Body and head entirely scaled, except on anteroventral surface of head. No scales on dorsal and anal-fin bases. Scales extending onto anterior 40 % of caudal fin. Frontal squamation D-patterned, frontal scales circularly arranged around A-scale without free margins; E-scales not overlapping; row of scales anterior to H-scale; supraorbital scales 6. Longitudinal series of scales 23–24; transverse series of scales 7; scale rows around caudal peduncle 16. Three contact organs on posterior margin of each scale of flank and opercular region. No contact organs on fin rays.

Cephalic neuromasts: supraorbital 1–2 + 3–4 + 4–5, parietal 2, anterior rostral 1, posterior rostral 1, infraorbital 1 + 10–15 + 1, preorbital 4, otic 1, post-otic 1, supratemporal 1, median opercular 1, ventral opercular 2, preopercular 8–10, mandibular 7, lateral mandibular 4–5, paramandibular 1. One neuromast per scale of lateral line. Two to four neuromasts on caudal-fin base.

Basihyal subtriangular, greatest width about 60 % of length; basihyal cartilage about 25 % of total length of basihyal. Six branchiostegal rays. Second pharyngobranchial teeth 2. Gill-rakers on first branchial arch 1 + 7. Vomerine teeth 2. Dermosphenotic present. Ventral process of posttemporal absent. Total vertebrae 25.

Coloration. Males. Sides of body dark brown to purplish brown, with oblique rows of small metallic blue to golden spots; dark metallic blue blotch on humeral region. Dorsum light brown. Venter light gray. Sides of head dark brown, opercle pale golden; dark gray to black infraorbital bar, adjacent to narrow preorbital light gray bar. Jaws pink. Iris yellowish brown, with black bar through center of eye. Exposed part of branchiostegal membranes dark gray. Dorsal fin golden, with 4–5 dark brown narrow bars on basal and posterior portion of fin; distal portion of median rays red. Anal fin dark brown, basal portion black, with row of 5–6 white to yellow vertically elongated spots along fin base and posterior margin; transverse rows of pale blue or pale yellow spots on subdistal region. Caudal fin dark gray, with transverse rows of small blue spots, often fused to form bars. Pectoral fins light reddish hyaline. Pelvic fins dark gray, with pale yellow spots.

Females. Sides of head and trunk light gray, sometimes with oblique rows of brown dots on dorsal portion of flank and caudal peduncle. Dorsum light brown. Venter light gray. Opercular region pale golden. Dark gray infraorbital bar, adjacent to narrow preorbital light gray bar. Jaws light brown. Iris yellow, with dark brown bar through center of eye. Unpaired fins hyaline, with faint small brown spots on basal portion.,Paired fins hyaline.

Etymology. From the Latin brevirostrata (with short snout), referring to the short snout contrasting with the big eyes of the new species.

Distribution and habitat. Known only from the type locality, a temporary lagoon in the rio Meia Ponte floodplains, city of Goiânia, Goiás, central Brazil ( Fig. 1 ).

Figures

FIGURE 1. Geographic distribution of the genus Pituna. Triangle = P. schindleri; inverted triangle = P. xinguensis; star = P. brevirostrata; dots = P. poranga; square = P. c o m p a c t a; asterisk = P. obliquoseriata. One symbol may represent more than one collecting site.

FIGURE 2. Pituna brevirostrata, UFRJ 6427, male holotype, 24.2 mm SL (one week after collection); Brazil: Goiás: Goiânia. Photo by W. J. E. M. Costa.

FIGURE 3. Pituna brevirostrata, UFRJ 6428, female paratype, female, 23.1 mm SL (one week after collection); Brazil: Goiás: Goiânia. Photo by W. J. E. M. Costa.

Tables

TABLE 1. Morphometric data for species of the genus Pituna.

P. brevirostrata		P. poranga
males (n = 5)	females (n = 5)	males (n = 10)	females (n = 7)
Standard length (mm) 17.5–24.2	21.4–27.6	27.9–32.6	23.3–29.6
Percentages of standard length
Body depth 25.8–27.7	25.2–25.7	21.3–24.6	18.1–23.8
Caudal peduncle depth 15.9–17.8	14.8–16.2	15.5–17.1	14.7–15.7
Pre-dorsal length 70.8–76.9	73.0–77.5	74.9–78.3	76.7–79.3
Pre-pelvic length 52.1–56.4	53.8–58.5	52.3–55.7	54.4–57.2
Length of dorsal-fin base 12.9–16.1	10.0–13.2	8.9–11.3	8.0–9.9
Length of anal-fin base 22.9–26.6	17.6–21.2	20.3–22.7	18.9–21.2
Caudal-fin length 38.8–41.6	36.3–38.6	36.3–38.7	37.2–39.6
Pectoral-fin length 23.6–26.0	22.2–24.5	22.6–26.1	23.3–25.8
Pelvic-fin length 14.1–18.2	11.9–13.8	12.7–14.9	12.5–13.9
Head length 34.5–35.2	31.6–34.0	29.0–31.7	29.2–32.4
Percentages of head length
Head depth 74.0–80.4	71.7–79.9	69.4–75.4	65.2–68.1
Head width 69.2–76.5	73.0–79.4	70.3–75.4	69.2–74.8
Snout length 9.4–12.5	10.2–12.0	12.0–13.7	11.9–13.5
Lower jaw length 14.4–17.0	12.8–16.3	18.1–20.3	15.1–19.0
Eye diameter 34.2–35.9	32.1–34.9	29.4–33.2	31.3–35.1