Hypsolebias gardneri Costa

Costa, Wilson J. E. M., Amorim, Pedro F. & Mattos, Jose Leonardo O., 2018, Cryptic species diversity in the Hypsolebiasmagnificus complex, a clade of endangered seasonal killifishes from the Sao Francisco River basin, Brazilian Caatinga (Cyprinodontiformes, Aplocheilidae), ZooKeys 777, pp. 141-158 : 141

Hypsolebias gardneri Costa sp. n. Figure 2, Table 2

Material examined.

Holotype.UFRJ 11859, male, 36.9 mm SL; Brazil: Bahia state: Malhada municipality: temporary pool near road BR-030, about 8 km NE of the village of Malhada, São Francisco River floodplains, 14°17'39"S, 43°42'32"W, altitude about 440 m above sea level (a.s.l.); W. J. E. M. Costa et al., 31 January 2010. Paratypes.UFRJ 6797, 3 males, 29.7-36.1 mm SL, 2 females, 27.9-30.0 mm SL; UFRJ 11860, 2 males, 30.6-33.0 mm SL, 2 females, 26.6-27.9 mm SL (C&S); UFRJ 6796, 3 males, 32.6-36.8 mm SL, 4 females, 26.5 - 29.3 mm SL (DNA); CICCAA02038, 2 males, 32.9-33.6 mm SL; all collected with holotype.

Diagnosis.

Hypsolebias gardneri differs from all other species of the H. magnificus complex, except H. harmonicus , by the following combination of character states relative to the male colour pattern: anterior part of the flank with three dark greenish grey bars (vs. dark greenish grey bars absent in H. hamadryades ); dorsal fin with transverse blue stripes and one basal row of blue dots (vs. rows of blue dots on the whole fin in H. picturatus ); anal fin with dots and short vermiculate marks irregularly arranged on the anterior part of the fin (vs. dots on the entire fin in H. picturatus , and transverse blue stripes on most fin in H. magnificus and H. hamadryades ); and anterior half of caudal fin with transverse rows of blue dots, posterior half with transverse blue bars (vs. blue bars on most fin in H. magnificus and dots on the entire fin in H. picturatus ). Hypsolebias gardneri is distinguished from H. harmonicus by having the caudal fin with 23 or 24 rays, subtruncate and longer in males, measuring 34.5-36.4% SL (vs. with 22 or 22 rays, round, measuring 31.2-33.2% SL), and from H. hamadryades by having the dorsal-fin origin just posterior to anal-fin origin in males (vs. anterior) and between the base of 3rd and 5th anal-fin rays in females (vs. between the base of 1st and 3rd anal-fin rays), and the second proximal radial of the dorsal fin between neural spines of the 7th and 8th vertebrae in males (vs. between neural spines of the 5th and 7th).

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 3 + 9, gill-rakers long, straight, without denticles. Urogenital papilla conical in males, pocket-shaped in females, slightly projecting over anterior part of anal fin.

Dorsal and anal fins relatively short, extremities rounded to slightly pointed in both sexes, without filamentous rays. Caudal fin subtruncate in males, rounded in females. Pectoral fin elliptical, posterior margin reaching between base of 6th and 9th anal-fin ray in males, reaching anus in females. Pelvic fin small, tip reaching between base of 3rd and 5th anal-fin rays in males, reaching base of 1st anal-fin ray in females; pelvic-fin bases medially united. Dorsal-fin origin at vertical between base of 1st and 2nd anal-fin rays in males, between base of 3rd and 5th anal-fin rays in females. Dorsal-fin rays 22-24 in males, 15-17 in females; anal-fin rays 21-22 in males, 17-19 in females; caudal-fin rays 23-24; pectoral-fin rays 12-; pelvic-fin rays 5-6. In males, minute papillate contact organs on inner surface three dorsal-most pectoral-fin rays. Second proximal radial of dorsal fin between neural spines of 7th and 8th vertebrae in males, between neural spines of 11th and 12th vertebrae in females; first proximal radial of anal fin between pleural ribs of 6th and 8th vertebrae in males, between pleural ribs of 8th and 9th 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 and gently extending on middle portion of anal-fin base; no scales on dorsal and pectoral-fin bases. Frontal squamation E-patterned; E-scales overlapping medially; no row of scales anterior to G-scale; supraorbital scales 1-2. Longitudinal series of scales 25-26; transverse series of scales 10; scale rows around caudal peduncle 12. One minute contact organ per scale of ventral portion of flank. Cephalic neuromasts: supraorbital 11-14; parietal 2; anterior rostral 1, posterior rostral 1; infraorbital 2 + 20-24; preorbital 3-4; otic 1-2, post-otic 2-3; supratemporal 1; median opercular 1, ventral opercular 2; pre-opercular 15-17, mandibular 10; lateral mandibular 4, paramandibular 1.

Colouration in life.

Males. Flank light blue on middle, light pink ventrally, and dark reddish orange dorsally and posteriorly; six to eight light red bars between humeral region and anterior part of caudal peduncle, more conspicuous anteriorly, three anterior-most red bars alternating with three dark greenish grey bars; minute vertically elongated metallic blue spots per scale, on whole flank. Dorsum pale reddish orange, venter white. Head light blue, margin of scales of dorso-posterior region reddish orange to golden. Iris yellow, with dark reddish brown bar through orbit centre. Unpaired fins dark red with bright blue marks, narrower than interspace, including six to nine transverse stripes and one basal row of dots on dorsal fin, stripes often interrupted and substituted by dots on posterior portion of sub-basal portion; dots and short vermiculate marks irregularly arranged on anterior portion of anal fin and transverse stripes on posterior portion; and seven or eight transverse rows of dots on caudal fin, coalesced to form bars on posterior half of fin; each unpaired fin with black line along distal margin. Paired fins red with black margin; minute light blue dots on pelvic fin. Females. Flank pale brownish grey, with faint vertically elongated grey spots and short bars along flank and one or two small black spots on flank centre at vertical between anus and anal-fin origin; anterior portion of flank pale golden. Dorsum pale brown, venter white. Head side pale blue with pale golden iridescence on opercle. Iris silver, with dark brownish grey bar through orbit centre. Fins hyaline.

Colouration in alcohol.

Males with similar colour pattern as in life, but iridescence is lost and red marks substituted by grey or inconspicuous. Females with similar colour pattern as in life, but iridescence in head is lost.

Distribution.

Hypsolebias gardneri is known only from the type locality (14°17'39"S, 43°42'32"W, altitude about 500 m a.s.l.; Figure 3), a wide temporary pool, with dense aquatic vegetation in open areas and bushes concentrated on part of the pool bank. Specimens of Hypsolebias pterophyllus Costa, 2012 were common in all parts of the pool, whereas specimens of H. gardneri have their distribution restricted to shadow areas, under marginal bushes. The pool was sampled a single time (31 January 2010), when the whole type series was collected. No similar pools were found in the region, thus it is not possible to evaluate its conservation status.

Etymology.

The name gardneri in honour of Scottish naturalist George Gardner, who was in the Caatinga during his trip to Brazil between 1836 and 1841, making rich natural history collections. His reports on the region, and the numerous plant species and Cretaceous fossil fish collected by him represent important landmarks of our knowledge about Caatinga biodiversity.