Hypsolebias splendissimus Costa

Costa, Wilson J. E. M., Amorim, Pedro F. & attos, Jose Leonardo O., 2018, Diversity and conservation of seasonal killifishes of the Hypsolebiasfulminantis complex from a Caatinga semiarid upland plateau, Sao Francisco River basin, northeastern Brazil (Cyprinodontiformes, Aplocheilidae), Zoosystematics and Evolution 94 (2), pp. 495-504 : 497-498

Hypsolebias splendissimus Costa sp. n. Figs 2, 3, Table 2

Holotype.

UFRJ 6909, male, 42.7 mm SL; Brazil: State of Bahia state: Municipality of Guanambi: temporary pool close to road BR-030, about 1.5 km W from the confluence between the Poço do Magro River and the Carnaíba de Dentro River, São Francisco River basin, and about 3 km W of the town of Guanambi, 14°12'54" S 42°50'22" W, altitude about 505 m asl; W. J. E. M. Costa et al., 30 January 2010.

Paratypes.

UFRJ 6779, 1 male, 43.3 mm SL, 2 females, 28.5-30.2 mm SL; UFRJ 6910, 1 male, 42.7 mm SL, 3 females, 26.7-30.5 mm SL (C&S); UFRJ 6778, 2 males, 33.7-36.2 mm SL, 6 females, 28.4 - 29.5 mm SL (DNA); collected with holotype.

Diagnosis.

Hypsolebias splendissimus differs from H. fulminantis and H. shibattai by having: pectoral fin red in males (vs. hyaline in H. fulminantis and H. shibattai ), well-developed filamentous rays on the tips of the dorsal and anal fins in adult males (vs. filamentous rays absent or rudimentary, poorly visible), and the second proximal radial of the dorsal fin between the neural spines of the 8th and 9th vertebrae in males (vs. between the neural spines of the 6th and 7th vertebrae). Also distinguished from H. shibattai by having the dorsal-fin origin posterior to the anal-fin origin in males (vs. anterior), distinctive red bars restricted to the anterior portion of the flank males (vs. extending over the whole flank), and absence of contact organs on the pectoral fin in males (vs. present).

Description.

Morphometric data appear in Table 2. Body relatively deep, compressed. Greatest body depth at vertical just anterior to pelvic-fin base. Dorsal and ventral profiles of head and trunk slightly convex, approximately straight on caudal peduncle. Head narrow, sub-triangular in lateral view. Jaws short, teeth numerous, conical, irregularly arranged; outer teeth hypertrophied, inner teeth small and numerous. Vomerine teeth absent. Gill-rakers on first branchial arch 2 + 10-11, gill-rakers short, straight, without denticles.

Dorsal and anal fins pointed in males, with two or three filaments on tip, rounded, without filaments, in females. Caudal fin rounded. Pectoral fin sub-lanceolate, posterior tip reaching vertical between base of 5th and 7th anal-fin rays in males, reaching between anus and urogenital papilla in females. Pelvic fin small, tip reaching base of 3rd anal-fin ray in males, reaching between urogenital papilla and anal-fin origin in females; pelvic-fin bases medially united. Dorsal-fin origin on vertical between base of 2nd and 4th anal-fin rays in males, between base of 4th and 6th anal-fin rays in females. Dorsal-fin rays 19-22 in males, 15-16 in females; anal-fin rays 21 in males, 18-19 in females; caudal-fin rays 23-24; pectoral-fin rays 12-13; pelvic-fin rays 6. No contact organs on fins. Second proximal radial of dorsal fin between neural spines of 8th and 9th vertebrae in males, between neural spines of 11th and 12th vertebrae in females; first proximal radial of anal fin between pleural ribs of 8th and 9th vertebrae in males, between pleural ribs of 9th and 10th vertebrae in females; total vertebrae 26-27.

Scales small, cycloid. Body and head entirely scaled, except anterior ventral surface of head. Body squamation extending over anterior 20 % of caudal-fin base; scales slightly extending on middle part of anal-fin base in males. Frontal scales E-patterned. Longitudinal series of scales 25-26; transverse series of scales 11; scale rows around caudal peduncle 12. One prominent contact organ on each flank scale in males. Cephalic neuromasts: supraorbital 12-16; parietal 2; anterior rostral 1, posterior rostral 1; infraorbital 3 + 22-24; preorbital 3-4; otic 2, post-otic 2; supratemporal 1; median opercular 1, ventral opercular 1-2; pre-opercular 15-16; mandibular 10-13; lateral mandibular 4, paramandibular 1.

Colouration in life.

Males. Flank intense red to pink on middle portion and metallic yellow ochre on anteroventral part; small, vertically elongated bright blue spot on centre of each scale; central portion of flank often with distinctive red bars, alternating with faint green bars, sometimes inconspicuous. Dorsum pale yellowish brown, venter yellowish white. Side of head metallic light blue, with red scale margins on dorsal portion and intense metallic yellow ochre on opercular, post-orbital and infra-orbital regions; snout and jaws light grey. Iris light yellow to pale orange, with dark brown bar through orbit centre. Unpaired fins red, with alternating short and long metallic blue lines to greenish golden lines, depending on angle of light incidence, parallel to fin rays; dorsal and anal fin filaments dark grey to black. Pelvic fin red with light blue rays. Pectoral fin red.

Females. Flank light brownish grey, to yellowish grey on dorsal portion and pale golden on anteroventral portion; two or three oval black spots on antero-central portion of flank; smaller specimens, about 28 mm SL or less, with dark grey bars, often interrupted; larger specimens above 28 mm SL, with dark grey spots on whole flank, often arranged in vertical rows, becoming dark grey to black around antero-central spots. Dorsum yellowish grey, venter white. Side of head yellowish grey, pale greenish golden on opercular and post-orbital regions; jaws light grey. Iris light yellow to pale orange, with dark brown bar through orbit centre. Fins yellowish hyaline.

Colouration in alcohol.

Trunk and head pale brown, with faint grey bars on anterior portion of flank in males, and grey spots on flank in females. Fins grey in males, hyaline in females. No vestige of red pigmentation and blue iridescent marks.

Distribution, habitat and conservation.

Hypsolebias splendissimus is known from a single collection at the type locality, a temporary pool in a flat plains area about 1.5 km W from the confluence between the Poço do Magro and Carnaíba de Dentro rivers, middle São Francisco River basin, Bahia, Brazil (14°12'54" S 42°50'22" W, altitude about 505 m asl; Fig. 4). At the time of the type series collection (30 January 2010) the pool was about 100 m long and 30 m wide, with a maximum depth of about 0.5 m. All individuals of H. splendissimus were concentrated in one part of the pool, near its margin, in an area about 100 m2, that was densely populated by shrubs and aquatic plants, forming a distinctive shaded habitat. This site was visited again in January 2017, but the entire pool had been drained and landfilled by bulldozers and the new species was not found again.

Etymology.

From the Latin splendissimus (very splendid), an allusion to the bright colours in males of the new species, which is among the most colourful South American aplocheiloid killifishes.