Maratecoara formosa Costa

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 : 34-36

Maratecoara formosa Costa & Brasil

( Figs. 25–26 )

Maratecoara formosa Costa & Brasil in Costa: 1995a: 69 (type locality: temporary pool in Brejinho de Nazaré, about 10°59’S, 48°38’W, Estado do Tocantins, Brazil; holotype: MNRJ 12521).

Material examined. Brazil: Estado do Tocantins, rio Tocantins basin: MNRJ 12521 (male holotype, 28.5 mm SL); MNRJ 12522 (2 paratypes); MZUSP 46081 (2 paratypes); UFRJ 2112 (4 paratypes); UFRJ 2111 (4 paratypes [c&s]); temporary pool in Brejinho de Nazaré, about 10°59’S, 48°38’W; W. J. E. M. Costa, G. C. Brasil & C. Campinha, 15 Feb. 1994.

Diagnosis. Distinguished from all other congeners by the following unique morphological features: body scales extending onto dorsal and anal-fin bases in males (vs. no scales on dorsal and anal-fin bases), dorsal profile of head strongly concave in adult males (vs. straight to slightly concave), and basal half of caudal fin with vertical rows of orange spots in males (vs. orange stripes parallel to fin rays). It is also distinguished from congeners by the following characters in combination: 25–26 caudal-fin rays (vs. 27–30), anteroventral portion of flank with four or five oblique orange bars (vs. broad orange blotch just posterior to pectoral-fin insertion), no distinctive bright blue zone on distal portion of anal fin (vs. broad bright blue zone in males), and a few pale orange spots on basal half of anal fin and flank region adjacent to anal fin, these often absent (vs. always conspicuously spotted).

Description. Morphometric data appear in Table 3 . Largest male examined 28.5 mm SL, largest female examined 22.3 mm SL. Dorsal profile strongly concave on head, convex from nape to end of dorsal-fin base, nearly straight on caudal peduncle. Ventral profile slightly convex from lower jaw to end of anal-fin base, approximately straight on caudal peduncle. Body deep, compressed. Greatest body depth at level of pelvic-fin base. Jaws short, snout slightly pointed.

Dorsal and anal fin long in males, pointed, terminating in long filamentous rays, tips surpassing posterior margin of caudal fin; dorsal and anal fins slightly pointed and short in females. Caudal fin lanceolate in males, with filamentous rays on posterior tip of fin; caudal fin rounded in females. Pectoral fins elliptical, posterior margin reaching vertical between base of 4th and 5th anal-fin rays in males, between urogenital papilla and anal-fin origin in females. Pelvic fins elliptical, without filaments; tip of each pelvic fin reaching base of 4th anal-fin ray in males, reaching between base of 1st and 2nd anal-fin rays in females. Pelvic-fin bases medially in close proximity. Dorsal-fin origin on vertical between base of 4th and 5th anal-fin rays, and between neural spines of 11th and 12th vertebrae. Anal-fin origin between pleural ribs of 10th and 11th vertebrae. Dorsal-fin rays 11–14; anal-fin rays 15–18; caudal-fin rays 25–26; pectoral-fin rays 13; pelvic-fin rays 8.

Scales large, cycloid. Body and head entirely scaled, except on anterior ventral surface of head. Body scales extending over anterior 30 % of caudal fin; and onto middle of dorsal and anal-fin bases. Frontal squamation F-patterned; E-scales not overlapping medially; scales arranged in regular transverse pattern. No scale anterior to H-scale. Four supraorbital scales. Longitudinal series of scales 25–27; transverse series of scales 9; scale rows around caudal peduncle 16. Three to five contact organs on posterior margin of each scale of ventral portion of flanks in males.

Cephalic neuromasts: supraorbital 6–7 + 4, parietal 3, anterior rostral 1, posterior rostral 1, infraorbital 1 + 20–22 + 1, preorbital 5, otic 1, post-otic 2, supratemporal 1, median opercular 1, ventral opercular 2, preopercular 14–16, mandibular 8–10, lateral mandibular 5. One neuromast on center of each scale of lateral line of trunk. Two neuromasts on caudal-fin base.

Basihyal narrow, longest width about 35 % of length; basihyal cartilage about 25 % basihyal length. Six branchiostegal rays. Three or four teeth on second pharyngobranchial. Gill-rakers of first branchial arch 1 + 6–8. Four or five vomerine teeth. Ventral process of posttemporal absent. Total vertebrae 26–27.

Coloration. Males: Sides of body metallic blue, with three horizontal rows of small dark orange spots on anterodorsal portion of flank; narrow oblique bars along ventral two thirds of flanks, first four or five bars orange, posterior bars pale purple; and purple stripe on lateral midline of caudal peduncle. Dorsum light brown. Venter white. Sides of head metallic blue, with small orange reticulation; dark gray to black infraorbital bar and triangular, dark orange supraorbital bar. Jaws orange. Iris bright green, with dark gray bar through center of eye. Dorsal fin metallic blue, transverse series of orange spots on basal portion, and rays orange to red on distal portion. Anal fin pale orange, with blue iridescence to light blue on basal portion, sometimes with faint orange spots on sub-basal portion. Caudal fin metallic blue, with transverse rows of dark orange spots on basal half and dark orange stripes parallel to fin rays on distal half of fin; anterior part of dorsal and ventral margins of fin red. Pectoral fins hyaline. Pelvic fins metallic blue, with orange spots.

Females: Sides of body light brownish gray, with longitudinal rows of pale brown dots. Dorsum light brownish gray. Venter white. Sides of head and jaws gray, pale greenish yellow or pale blue on opercle; dark gray infraorbital bar. Iris yellow, with gray bar through center of eye. Fins hyaline.

Distribution and habitat. Seasonal lagoons in the middle rio Tocantins floodplains, ( Fig. 22 ), in a typical savannah area.

Figures

FIGURE 22. Geographic distribution of the genus Maratecoara. dots = M. lacortei; square = M. splendida; lozenge = M. formosa. One symbol may represent more than one collecting site.

FIGURE 25. Maratecoara formosa, male paratype, 27.5 mm SL, UFRJ 2112 (some minutes after collection); Brazil: Tocantins: Brejinho de Nazaré. Photo by W. J. E. M. Costa.

FIGURE 26. Maratecoara formosa, female paratype, 22.3 mm SL, UFRJ 2112 (some minutes after collection); Brazil: Tocantins: Brejinho de Nazaré. Photo by W. J. E. M. Costa.