Maratecoara lacortei (Lazara)

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 : 32-34

Maratecoara lacortei (Lazara)

( Figs. 23–24 )

Cynolebias lacartei Lazara, 1991: 141 (type locality: temporary pool, Aruana [ Aruanã , road GO-173], Goias [Estado de Goiás], Brazil [14º57’0.5”S, 51º1’23.7”W, altitude 243 m]; holotype: MZUSP 38805).

Material examined. All material collected in the Araguaia-das Mortes basin. Brazil: Estado de Goiás: UFRJ 6417 (1); UFRJ 6418 (2, c&s); temporary lagoon, road GO-173, Aruanã , 14º57’0.5”S, 51º1’23.7”W; W. J. E. M. Costa, C. P. Bove, J. Paz & A. Oliveira, 13 Apr. 2006. Estado de Estado do Tocantins: UFRJ 6403 (26); UFRJ 6405 (8, c&s); UFRJ 6406 (3); temporary pool in rio Formoso floodplains, road BR-242, 11º47’31.6”S, 49º45’54.7”W; W. J. E. M. Costa, C. P. Bove, J. Paz & A. Oliveira, 15 Apr. 2006. UFRJ 3796 (22), same locality as UFRJ 6403; D. T. B. Nielsen, A. Carletto & A. de Luca, 6 Apr. 1996. UFRJ 5264 (21); Parque Nacional do Araguaia, ilha do Bananal; G. C. Brasil, D. Almeida & R. D’Arrigo, 20 Feb. 1999. UFRJ 3555 (2); UFRJ 3556 (1, c&s); temporary lagoon near Barreira do Pequi; W. J. E. M. Costa, M. I. Landim, G. C. Brasil & C. Moreira, 15 Feb. 1996. Estado de Mato Grosso: UFRJ 3551 (2), UFRJ 3542 (1, c&s); temporary lagoon 9 km E of rio das Mortes, road MT-326; W. J. E. M. Costa, M. I. Landim, G. C. Brasil & C. Moreira, 16 Feb. 1996. UFRJ 275 (1); UFRJ 1155 (2); MZUSP 41388 (1); MZUSP 41389 (4); MZUSP 41390 (3, c&s); same locality; G. C. Brasil et al., Jan. 1988.

Diagnosis. Distinguished from all other species of the genus by the following unique morphological features: 27–30 caudal-fin rays (vs. 25–27), anteroventral portion of flanks with broad orange blotch just posterior to pectoral-fin insertion (vs. three to five oblique orange bars), and distal portion of anal fin with broad bright blue zone in males (vs. no distinctive bright blue zone). Also distinguished from congeners by the following characters in combination: no scales on dorsal and anal-fin bases (vs. scales extending onto dorsal and anal-fin bases in males); dorsal profile of head straight to slightly concave in adult males (vs. strongly concave); 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); and basal half of caudal fin with orange stripes parallel to fin rays in males (vs. with vertical rows of orange spots).

Description. Morphometric data appear in Table 3 . Largest male examined 33.4 mm SL, largest female examined 30.6 mm SL. Dorsal profile straight to slightly concave on head, convex from nape to end of dorsalfin base, approximately straight on caudal peduncle. Ventral profile gently 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. 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 5th and 7th 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 between base of 5th and 6th anal-fin rays in males, reaching to between base of 3rd and 4th anal-fin rays in females. Pelvic-fin bases in close proximity medially. Dorsal-fin origin on vertical between base of 4th and 6th anal-fin rays, and between neural spines of 11th and 13th vertebrae. Anal-fin origin between pleural ribs of 10th and 11th vertebrae. Dorsal-fin rays 11–13; anal-fin rays 15–17; caudal-fin rays 27–30; pectoral-fin rays 13; pelvic-fin rays 8.

Scales large, cycloid. Body and head entirely scaled, except anterior ventral surface of head. Body squamation extending over anterior 25 % of caudal fin; no scales on 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 25–26; transverse series of scales 9–10; scale rows around caudal peduncle 16. Three to five contact organs on posterior margin of each scale on ventral portion of flanks in males.

Cephalic neuromasts: supraorbital 6–7 + 3–4, parietal 3, anterior rostral 1, posterior rostral 1, infraorbital 1 + 24–27 + 1, preorbital 4–6, otic 1, post-otic 2, supratemporal 1, median opercular 1, ventral opercular 1, preopercular 15–16, mandibular 9–10, lateral mandibular 6. 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 % of basihyal length. Six branchiostegal rays. Three to six teeth on second pharyngobranchial. Gill-rakers of first branchial arch 1 + 6–8. Two vomerine teeth. Ventral process of posttemporal absent. Total vertebrae 27–28.

Coloration. Males: Sides of body metallic blue to purplish blue above anal fin; two or three horizontal rows of small dark orange spots on anterodorsal portion of flank, often posteriorly fused to form stripes; large orange blotch on anteroventral portion of flanks just posterior to pectoral fin insertion; one horizontal row of reddish orange spots (sometimes forming stripe) on lateral midline of caudal peduncle. Dorsum light brown. Venter white. Sides of head metallic blue, with small orange spots; dark gray to black infraorbital bar and triangular, dark orange supraorbital bar. Jaws orange. Iris bright green, with black bar through center of eye. Dorsal fin metallic blue, with 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 subproximal portion; broad bright blue zone on distal portion of fin. Caudal fin metallic blue, with orange stripes parallel to fin rays, two basal stripes shortly extending on caudal peduncle; 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 on dorsal portion of flank. 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 dark gray bar through center of eye. Fins hyaline.

Distribution and habitat. Seasonal swamps, lagoons and pools in the Araguaia–das Mortes river basin, ( Fig. 22 ), in typical savannah areas or transitional regions between savanna and the Amazonian forest.

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 23. Maratecoara lacortei, male, 28.8 mm SL, UFRJ 6406 (one day after collection); Brazil: Tocantins: rio Formoso floodplains. Photo by W. J. E. M. Costa.

FIGURE 24. Maratecoara lacortei, female, 24.4 mm SL, UFRJ 6406 (one day after collection); Brazil: Tocantins: rio Formoso floodplains. Photo by W. J. E. M. Costa.