Laimosemion laranja Abrantes, Lima, Nielsen, Lira, Silva & Berbel-Filho, 2026, sp. nov.

Laimosemion laranja sp. nov. Figs 2, 3 Holotype. INPA-ICT 062600, 26.8 mm SL, male, Brazil, Amapá, Laranjal do Jari municipality, Igarapé Massaranduba, Rio Cajari, tributary of the Rio Amazonas Basin, 00°48'43.46"S, 052°28'47.56"W, 21 Jun 2025, S. Lima, W. Berbel-Filho, Y. G. Abrantes. Paratypes. All from Brazil, Amapá, Laranjal do Jari Municipality, Rio Cajari. INPA-ICT 062601, 1 male 19.7 mm SL, 1 female 20.1 mm SL, same data as holotype. INPA-ICT 062602, 2 males 21.0–25.0 mm SL, 3 females 19.8–20.9 mm SL, same data as holotype. MNRJ 56199, 4 males 22.6–27.8 mm SL, 3 females 18–20.6 mm SL, 00°49'33.4"S, 052°30'15.7"W, 21 Jun 2025, S. Lima, W. Berbel-Filho, Y. G. Abrantes. UFRN 6297, 4 males 21.2–22.5 mm SL, 1 female 17.5 mm SL, UFRN 6428, 1 male (c & s), 1 female (c & s), 00°37'06.35"S, 052°22'09.02"W, 21 Jun 2025, S. Lima, W. Berbel-Filho, Y. G. Abrantes. UFRN 6058, 2 males 16.1–20.3 mm SL, 3 females 15.8–19.9 mm SL, 00°37'06.35"S, 052°22'09.02"W, 27 Mar 2024, W. Berbel-Filho, Y. G. Abrantes. UFRN 6059, 2 males 22.9–25.4 mm SL, 1 female 13.6 mm SL, 00°49'33.4"S, 052°30'15.7"W, 27 Mar 2024, W. Berbel-Filho, Y. G. Abrantes. Diagnosis. Laimosemion laranja differs from the six congeners of the L. geayi group by having eight scales in transverse series (vs. 7 in L. dibaphus and L. strigatus, 9 in L. geayi, 9–10 in L. agilae and L. cladophorus, and 9–11 in L. mabura). It can be distinguished from all other congeners of the L. geayi group, except L. agilae and L. cladophorus, by dorsal-fin origin positioned on transversal plane through bases of 4 th – 6 th anal-fin rays in both sexes (vs. of 7 th – 8 th anal-fin rays). It differs from L. agilae by frontal squamation pattern of head (E squamation vs. F squamation) and from L. cladophorus by presenting lower number of longitudinal scales series (30–32 vs. 34–37) and flanks light gray (vs. blue-green metallic). It is further distinguished from L. mabura by possessing 13–14 anal-fin rays (vs. 11–12), from L. geayi by anal-fin origin on transversal plane through 11 th – 12 th vertebrae (vs. of 7 th – 8 th vertebrae). It differs from L. strigatus by possessing lower number of vertebrae (28 vs. 30–31), and by presenting lower number of peduncle scales series (10–13 vs. 16). The new species differs from L. dibaphus by absence of parhypural process on caudal fin (vs. present), and by lower number of neuromasts in infraorbital series (8–10 vs. 12–16). Description. Morphometric data are presented in Table 1. The largest male measured 27.8 mm SL; the largest female 20.6 mm SL. Body slender, subcylindrical anterior plane and compressed posteriorly. Dorsal profile slightly convex from snout to end of dorsal-fin base, straight to slightly concave on caudal peduncle. Ventral profile convex, concave on caudal peduncle. Head narrow, elliptical in lateral view, snout blunt. Mouth superior, jaws short; teeth numerous, conical, irregularly arranged; outer teeth large, inner teeth small and numerous. Eyes positioned on upper lateral portion of the head. Urogenital papilla unexposed in males and females. Dorsal and anal fins pointed in males and rounded in females. Pectoral fins rounded. Pelvic fins pointed; tips reaching anal-fin origin in males and females. Caudal fin subtruncate in males, rounded in females. Dorsal-fin origin at transversal plane through anal fin in males; anal-fin origin at vertical plane through base of 4 th – 6 th dorsal-fin ray in males and females. Anal-fin origin on transversal plane through 11 th – 12 th vertebrae in males and females. Dorsal-fin rays 9–10 in males, 8–9 in females; anal-fin rays 13–14; caudal-fin rays 26–27 in males, 26–28 in females; pectoral-fin rays 13–15; pelvic-fin rays 6–7. Cephalic neuromasts: supraorbital 4 + 2, parietal 1, anterior rostral 1, posterior rostral 1, infraorbital 10, preorbital 3, otic 1, post-otic 1, supratemporal 1, median opercular 1, ventral opercular 1–2, preopercular 4–5, mandibular 17–18, lateral mandibular 5, and paramandibular 4. Contact organs absent on fins. Frontal squamation E-patterned; E-scales not overlapping medially; scales arranged in regular circular pattern around A-scale; longitudinal scale series 31–32; transverse scale series 8; scale rows around caudal peduncle 10–13. Total vertebrae 28. Coloration in life. Male (Fig. 2): Flank light gray on anterior portion, dark gray on posterior portion, four to five incomplete longitudinal rows of sometimes coalescent orange dots on anterior portion of flank, five to six orange chevron-like oblique bars on posterior region of the flank; dark humeral blotch. Venter white. Opercular region bluish gray with orange blotch. Jaw gray. Iris dark brown, posterior portion light blue. Dorsal fin orange with large blue spots. Caudal fin light blue with five to six orange vertical bars not reaching ventral submargin. Anal fin greenish orange with pale blue spots, and black stripe distal marginal line. Pectoral fins hyaline with thin distal black marginal line. Pelvic fins greenish orange, with orange anterior marginal line with dark, grayish submargin. Female (Fig. 3): Sides of flank light gray, five to six irregular rows of orange spots on anterocentral portion; dark humeral blotch. Venter white. Opercular region pale yellow with irregularly arranged orange dots. Jaw dark gray. Infraorbital region pale green. Dorsal fin greenish with pale blue spots and light brown blotch. Caudal fin yellowish green with dark bar on dorsal and ventral portion, and a reddish dark marginal stripe on anterior portion. Anal fin greenish yellow, with gray-bluish basal portion, reddish on anterior portion, and dark gray to blackish on distal portion. Pectoral fins yellowish hyaline. Pelvic fins hyaline. Coloration in alcohol. Males: The iris white. Flank light brown on anterior region, five to six dark brown chevron oblique bars on posterior region of flanks. Opercular region dark brown. Venter white. Pelvic and pectoral fin hyaline. Dorsal and caudal fins light gray. Caudal with five dark bars. Anal fin light gray with dark spots on posterior region. Female: Iris white. Sides of flanks pale brown. Opercular region pale brown. Venter white. Dorsal and caudal fins with light brown spots on posterior and anterior region, respectively. Pectoral, pelvic, and anal fins hyaline. Geographic distribution. Laimosemion laranja is known from three localities in the lower portion of the Rio Cajari tributary of the Rio Amazonas Basin, in the municipality of Laranjal do Jari, Amapá State, northern Brazil (Figs 1, 4). The Rio Cajari, draining in the lower Amazonas drainage, is part of the Amazonas Estuary and Coastal Drainages Freshwater Ecoregion (Melo et al. 2016). Habitat and ecological notes. The climate of southern Amapá State is characterized by a tropical rainforest climate according to the Köppen – Geiger climate classification (Peel et al. 2007). The average annual temperature is 26.4 ° C, with intense rainfall between March and May, including an average accumulation of 2,500 mm per year (ICMBio 2025). The new species was collected in pools adjacent to the main course of streams located in three forested sites. The pools had floating aquatic vegetation, clear water with moderate currents, sandy or muddy substrate, and depths between 0.5 and 1 m (Fig. 4). Laimosemion laranja was found syntopically with Anablepsoides jari, Poecilia waiapi Bragança, Costa & Gama, 2012, Hoplerythrinus unitaeniatus (Spix & Agassiz, 1829) and Brachyhypopomus sp. at a sampling site in the city of Laranjal do Jari. Etymology. The specific epithet ‘ laranja’ is a name with a dual allusion. It refers to the bright orange color pattern on males of the new species (‘ laranja’ means the color, as it also means the fruit in Portuguese), and is also an homage to the municipality of Laranjal do Jari, founded on December 17, 1987, in the south of Amapá State, Brazil, from where the species is currently only found. A noun in apposition. Conservation status. Laimosemion laranja occurs in three locations with environmental disturbance due to anthropic actions. The first site (00°37'06.4"S, 052°22'09.0"W) is on the boundary of the Reserva Extrativista do Rio Cajari (Brasil 1990). Although located only a few meters from the conservation unit, the habitat where the species occurs showed signs of deforestation, including burned trees (Fig. 4 a). Some pools were identified by local residents as remnants of mining activities, exhibiting water with high concentrations of suspended solids and an intense reddish color (ICMBio 2025). About 24 km south of the first site (00°48'43.46"S, 052°28'47.56"W), the species’ type locality is located 180 m from the city of Laranjal do Jari’s electric power substation. The third site is located three kilometers south of the type locality (00°49'33.4"S, 052°30'15.7"W), in a forested stream within the city. At this site, urbanization is causing habitat loss and plastic pollution in the wetlands where the new species is found. Therefore, due to the continuous decline of habitat caused by impacts identified and restricted geographic distribution with an extent of occurrence (EOO) calculated at 25 km 2 (<100 km 2) and an occupancy area (AOO) of 12 km 2 (<500 km 2), this species should be classified as ‘ Endangered’ (EN), according to criteria B 1 ab (iii) + B 2 ab (iii) of the International Union for Conservation of Nature (IUCN 2022). Comparative material (All from Brazil). Laimosemion geayi: UFRN 6101, 2 males, 25–28.6 mm SL, 1 female, 22.8 mm SL, Amapá, Oiapoque, Rio Oiapoque Basin. UFRN 6102, 2 males 27.4–28.3 mm SL, 2 females, 19.9–26.6 mm SL; UFRN 6430 2, 1 male (c & s), 1 female (c & s) Amapá, Oiapoque, Rio Oiapoque Basin. UFRN 6103, 3 males, 25.2–29.5 mm SL, 2 females 19.9–26.6 mm SL, Amapá, Oiapoque, Rio Oiapoque Basin. Laimosemion strigatus: UFRN 6050, 1 male 23.6 mm SL, 1 female 19.4 mm SL, Pará, Primavera, Rio Japerica Basin. Laimosemion dibaphus: UFRN 6333, 5 males 21–27.7 mm SL, 4 females 18.3–21.5