Hypsolebias lulai, Ramos & Nielsen & Abrantes & Lira & Lustosa-Costa, 2023

Ramos, Telton P. A., Nielsen, Dalton T. B., Abrantes, Yuri G., Lira, Fabio Origuela de & Lustosa-Costa, Silvia Y., 2023, A new species of cloud fish of the genus Hypsolebias from Northeast Brazil (Cyprinodontiformes: Rivulidae), Neotropical Ichthyology (e 230068) 21 (3), pp. 1-15 : 4-8

Hypsolebias lulai , new species urn:lsid:zoobank.org:act:19E2B0DD-8AC9-4AB3-9D87-B251620BDF6A

( Figs. 1–2 , 6 ; Tab. 1)

Holotype. UFPB 14713 , 44.9 mm SL, male, Brazil, Rio Grande do Norte State, Lagoa Salgada Municipality, Capim Grosso Lagoon, Recanto II settlement, Trairi River basin, 06°10’S 35°31’W, 4 Aug 2022, T. P. A. Ramos, S. Y. Lustosa-Costa & Y. G. Abrantes.

Paratypes: All from Brazil. Trairi River basin, Rio Grande do Norte State: UFPB 13354 , 3 females (35.9–40.9 mm SL), collected with holotype, Lagoa Salgada , Capim Grosso Lagoon , Recanto II settlement, 06°10’S 35°31’W, 4 Aug 2022, T. P. A. Ramos, S. Y. Lustosa-Costa & Y. G. Abrantes. UFPB 13352 , 4 males (37.5–50.4 mm SL), 20 females (32.8–40.6 mm SL), Lagoa Salgada, Malhadas Dam, Recanto II settlement, 06°10’57”S 35°31’35”W, 4 Aug 2022, T. P. A. Ramos, S. Y. Lustosa-Costa & Y. G. Abrantes. UFPB 13353 , 4 males (44.9–51.1 mm SL), 8 females (34.9–40.3 mm SL), Lagoa Salgada, Quixabeira Dam, Recanto II settlement, 06°10’33”S 35°31’47”W, 4 Aug 2022, T. P. A. Ramos, S. Y. Lustosa-Costa & Y. G. Abrantes. UFRN 5905, 5 males (40.4–45.8 mm SL), 4 females (38.1–41.2 mm SL), Lagoa Salgada, Malhadas Dam, Recanto II settlement, 06°10’57”S 35°31’35”W, 4 Aug 2022, T. P. A. Ramos, S. Y. Lustosa-Costa & Y. G. Abrantes .

Diagnosis. Hypsolebias lulai differs from the remaining species of the H. flammeus species-group, by the male body color pattern s ides of body metallic blue, with 14–18 slim reddish brown bars, this bars are prominent on the caudal penduncle and lose definition near of the pelvic fin (vs. reddish brown wide bar alternating in a bright blue background), by the anal fin color pattern light blue, with 11 reddish brown bars (vs. being bright blue in H. tocantinensis , H. brunoi , H. flammeus , H. multiradiatus , bright brownish yellow with 9–10 dark brown to black bars slightly posteriorly inclined in H. delucai , bright brownish yellow, with 8–11 reddish gray bars slightly posteriorly inclined in H. alternatus , light pinkish gray, with 9–10 reddish brown bars in H. fasciatus , metallic greenish blue, with 11–13 pale reddish brown bars in H. longignatus ); absent bars in caudal fin and dorsal fin in males (vs. presence). Additionally, H. lulai differs from the remaining species of the H. flammeus species-group except from H. multiradiatus and H. longignatus by the high number of dorsal fin rays in males 26 (vs. 18–23 of the other species in the group); differs from H. multiradiatus and H. longignatus by the high number of scales in longitudinal series 30 (vs. 26–27 in H. multiradiatus and 24–26 in H. longignatus ).

Description. Morphometric data presented in Tab. 1. Largest specimen examined 51.1 mm SL. Body relatively deep, laterally compressed, greatest body depth at level of pelvic fin origin in male. Snout blunt. Dorsal profile concave on head, moderately convex from nape to end of dorsal-fin base posterior, nearly straight or moderately concave on caudal peduncle. Ventral profile convex from lower jaw to the end of anal fin base, nearly straight on caudal peduncle. Eyes positioned on upper portion of side of head. Urogenital papilla cylindrical and short in males, pocket-shaped in females.

Tip of dorsal and anal fins pointed in males, with one or two short filamentous rays on tip reaching vertical through caudal-fin base; extremity of dorsal and anal fin rounded in females, filaments absent in females. Caudal fin rounded. Pectoral fins elliptical. Posterior margin of pectoral fins reaching vertical through base of 3th anal-fin ray in males; in females the posterior margin of pectoral fins it does not reach the base of the anal-fin, reaches half the length of the pelvic fin. Tip of each pelvic fin reaching base of 3rd anal-fin ray separated by interspace equal to pelvic-fin base in width, in males; in females the tip of each pelvic fin reaching base of 1rd anal-fin ray. Dorsal-fin origin on vertical anterior to pelvic-fin origin in males; in females, between origins of pelvic- and anal-fins. Anal-fin origin on vertical through base of fourth dorsal-fin ray, in males and in females anterior to dorsal-fin origin. Anal-fin origin on vertical through base of fourth dorsal-fin ray, in males and in females anterior to dorsal-fin origin. Dorsal-fin origin between neural spines of vertebrae 6 and 7 in males, and neural spines of vertebrae 11 and 12 in females. Anal-fin origin between pleural ribs of vertebrae 7 and 8 in males, and pleural ribs of vertebrae 8 and 9 in females. Dorsal-fin rays 26 in males, 18–21 in females; anal-fin rays 23–24 in males, 20–23 in females; caudal-fin rays 21; pectoral-fin rays 12–13; pelvic-fin rays 6. Longitudinal series of scales 30-32; transverse series of scales 11–12; scale rows around caudal peduncle 12–13. Small papillae contact organ only on inner surface of three dorsal-most rays of pectoral fins in males, absent in scale of flank and ventral portion of opercular area. Total vertebrae 26.

Cephalic neuromasts: supraorbital 15, preorbital 2–3, infraorbital 3 + 23–24, parietal 2, anterior rostral 1, posterior rostral 1, otic 2, post-otic 2, supratemporal 1, median opercular 1–2, ventral opercular 3–4, preopercular plus mandibular 28–30, lateral mandibular 8, paramandibular 1. One or two neuromasts on center of each scale of lateral line, anal and caudal fins base.

Coloration in life. Males ( Fig. 1 ). Sides of body metallic blue, with 14–18 slim reddish brown bars, this bars are prominent on the peduncle caudal and lose definition near of the pelvic fin. Dorsum reddish brown with the scales edge in metallic blue. Venter pale orange. Opercular region light metallic yellow. Iris light yellow, with dark black bar. Dorsal fin reddish brown with blue spots and dots, with small filaments. Anal fin light blue, with 11 reddish brown bars, presence of small filaments at the tip of each ray. Caudal-fin light reddish brown with blue spots and dots and distal area hyaline. Pectoral fins hyaline. Pelvic blue. Females ( Fig. 2 ). Body sides light gray, with gray bars from peduncle to opecular area, black spot in central of body. Dorsum gray. Ventral area pale yellow. Opercular region light gray. Iris light yellow, with dark gray stripe through center of eye. Dorsal fins, anal fin, pectoral, pelvic and caudal fins hyaline.

Geographical distribution. Hypsolebias lulai was recorded in three bodies of water in the rural area of the municipality of Lagoa Salgada, state of Rio Grande do Norte, within the Caatinga biome ( Fig. 3 ). Two of the three bodies of water where the species was recorded are artificial, being reservoirs of the small Malhadas and Quixabeira dams. The third body of water is a temporary natural pool known as Capim Grosso. Due to the heavy rains in the period (2022), the temporary pool overflowed, resulting in the release of water into the two artificial reservoirs below, in a cascading effect. However, the natural location of the new species is probably just the Capim lagoon, and its record in the artificial reservoirs was caused by the heavy rains that caused this lagoon to overflow and the fish to reach the reservoirs.

Ecological notes. The habitat is a temporary lagoon in the drainage of the rio Trairi basin, a river that has its upper and middle courses in the Caatinga biome and its mouth in the Atlantic Forest biome ( Fig. 4 ). The substrate of the lagoon is composed of clay and sand and the water is a slightly dark tea-color. The lagoon reached a depth of 2 m during the sampling period, but its average depth is about 1.3 m. The aquatic vegetation is dense with abundant Echinodorus sp. and Nymphea sp. The average annual temperature in the region is 28º C, with a maximum of 34º C and a minimum of 20º C. The rainy season occurs from January to June. Hypsolebias lulai was found with Astyanax bimaculatus (Linnaeus, 1758) at the type-locality and A. bimaculatus and Oreochromis niloticus (Linnaeus, 1758) in the artificial reservoirs. Individuals of the new species were also collected in areas of currents in the drainages that formed between the water bodies of Lagoa Capim Grosso and Malhadas and Quixabeira dams.

Etymology. The species is named in honor of Luiz Inácio Lula da Silva, the current Brazilian president, responsible for restoring conservation actions and socioenvironmental enhancement and resuming incentives for Brazilian science. A patronym.

Conservation status. Hypsolebias lulai is an endemic species in the semi-arid region, occurring only a small pond in the Trairi River basin, State of Rio Grande do Norte, Brazil. The species is limited to just three sampling points, all interconnected, in a heavily occupied and modified area. Due to the significant impact of agriculture in the region where this species was recorded, as well as the presence of an exotic species, Oreochromis niloticus , in two of the three registration points for H. lulai , the species faces several threats. First, its restricted area of occupation, which covers less than 1 km ². Second, the conversion of Caatinga areas into pastures and also the construction of dams in natural wetlands, which drives to decline in habitat quality. For these reasons, we categorize the new species described as Vulnerable (VU), according to the D2 criterion of the International Union for Conservation of Nature (IUCN Standards and Petitions Subcommittee, 2022).

Figures

FIGURE 1 | Hypsolebias lulai, holotype, UFPB 14713, 44.9 mm SL, male; Brazil, Rio Grande do Norte, Lagoa Salgada, Coelho stream, rio Trairi basin.

FIGURE 2 | Hypsolebias lulai, paratype, UFPB 13354, 40.9 mm SL, female; Brazil, Rio Grande do Norte, Lagoa Salgada, Coelho stream, rio Trairi basin.

FIGURE 3 | Type-locality of species of Hypsolebias flammeus species-group.

FIGURE 4 | Type-locality of Hypsolebias lulai, Brazil, Rio Grande do Norte, Lagoa Salgada, Coelho stream, rio Trairi basin.

FIGURE 6 | Hypsolebias lulai, male, 50.6 mm SL, Brazil, Rio Grande do Norte, Lagoa Salgada, Coelho stream, rio Trairi basin.