Eigenmannia zenuensis, Lopes E Silva & Andrade & Maltoni & Lannes, 2020

Herrera-Collazos, Edgar Esteban, Galindo-Cuervo, Aleidy M., Maldonado-Ocampo, Javier A. & Rincón-Sandoval, Melissa, 2020, Three new species of the Eigenmannia trilineata species group (Gymnotiformes: Sternopygidae) from northwestern South America, Neotropical Ichthyology (Cambridge, England) 18 (1), No. 180085, pp. 1-28 : 19-20

Eigenmannia zenuensis , new species

urn:lsid:zoobank.org:act:F95204EB-E0B9-477D-B4C8-B85ED9CED607

( Figs. 7 , 9 ; Tab. 10 )

Holotype. CZUT-IC 11030, 127.2 mm LEA, (COI: GenBank MN832885 ), Colombia, Sucre, Montegrande creek, tributary San Jorge river , Lower Magdalena, Cauca, San Jorge basin, 8°42’26.96”N 75°14’28.83” W, J. I. Mojica & F. Rodríguez.

Paratypes. CZUT-IC 8321 , 3 , 8.8–13.3 mm LEA, Colombia, Sucre, bridge Santodomingo creek, Lower Magdalena, Cauca, San Jorge basin, 8°38’06.20”N 75°15’38.11”W. J. I. Mojica & F. Rodríguez. ICN-MHN 2020 , 9.0- 9.1 1 c&s, Colombia, Córdoba, San Jorge river, Ayapel marsh, Lower Magdalena, Cauca, San Jorge basin, 8°26’20.54”N 75°04’23.08”W, J. I. Mojica & F. Rodríguez. CZUT-IC 8299 , 18 + 1c&s, 5.1–11.3 mm LEA, Colombia, Sucre, creek via San Marcos, turnoff, Lower Magdalena, Cauca, San Jorge basin, 8°39’43.06”N 75°12’12.65”WA. Vanegas & J. Peña .

Non-types. CZUT-IC 8335 , 2 , 12.5–15.9 mm LEA, Colombia, Sucre, Vicente creek, tributary Montegrande creek , Lower Magdalena, Cauca, San Jorge basin, 8°42’05.35”N 75°14’24.73”W . CZUT-IC 11020 , 1 , 12.8 mm LEA, Colombia, Sucre, Vicente creek, tributary Montegrande creek , Lower Magdalena, Cauca, San Jorge basin, 8°42’05.35”N 75°14’24.73”W , J. I. Mojica & F. Rodríguez.

Diagnosis. Eigenmannia zenuensis can be distinguished from congeners in the E. trilineata species group by the higher number of teeth in the dentary: 56–60 in 4–5 rows (vs. 8–15 in 1–2 rows in E. antonioi ; 11–16 in 1–2 rows in E. muirapinima ; 15–21 in 2 rows in E. pavulagem ; 16 in 2 rows in E. microstomus ; 16–18 in 2 rows in E. correntes ; 17–18 in 2 rows in E. guairaca ; 17– 9 in 1–2 rows in E. loretana ; 19–26 in 2 rows in E. sayona ; 19–30 in 2–3 rows in E. besouro ; 20–22 in 2 rows in E. camposi ; 21–23 in 2 rows in E. desantanai ; 23 in 2 rows in E. trilineata ; 25-27 in 2 rows in E. matintapereira ; 35–39 in 2–3 rows in E. magoi ; 37–38 in 4 rows in E. waiwai and 38–45 in 3–4 rows in E. vicentespelaea ).

Description. Morphometric and meristic data is shown in Tab. 9 . Total Length (mm): 151.0–237.0. Ovoid scapular foramen. 69–86 vertebrae. 14–15 precaudal vertebrae. 31–34 premaxillary teeth in 4–5 rows. 7–11 endopterygoid teeth in 1–2 rows. 56–60 teeth in dentary in 4–5 rows. Scales small, cycloid, extending from immediately posterior of head to tip of caudal filament, presents. Suture between parietal and frontal bones serrated with similar teeth size. Posterior-most arm of the lateral ethmoid bone elongated and articulates with anterior-most prolongation of the frontal bone forming a window. Vomer with two extensions in base, forming groove with inverted crescent shape, posterolateral margins approximately the same width as parasphenoids. Width of anterior region of parasphenoid bone equal to width of both premaxillaries. Parasphenoid wide in anterior region; becomes narrower and forking posteriorly. Orbitosphenoid bone wide. Pterosphenoid bone wide. Posterior edge of the pterotic bone not completely rounded, has linear and non-curved edges. Posterior-most extension with right-angled triangular shape. Posterior base of basioccipital bone prolonged, bone itself not very round. Branchiostegal rays, 5 in total, 1–2 of same length, 3–5 with wide extensions, branchiosteal 4 the largest, sometimes branchiostegal 2 is large. Urohyal convex sheet reaches medial section of bone. Operculum upper edge rounded. Endopterygoid with long ascendant process. Basihyal length approximately 3/4 length of first ceratobranchial, slightly wider in anterior region, almost rectangular. Ceratobranchials with width conserved. 4–5 basibranchials, 2–3 well ossified. Four hypobranchials, first 3 well ossified. Upper pharyngeal tooth plate with 7 teeth. Lower pharyngeal tooth plate with 12 teeth. 9–10 cartilaginous gill rakers.

Coloration in alcohol. Background color pale cream to pale yellow. Head dark, darker than the rest of the body, darker in the dorsal region and lighter just by the dorsal region. Lips and suborbital region generally dark with concentrated chromatophores. Body with four visible dark stripes. Body darker above the lateral-line stripe. Lateral-line stripe dark, one scale deep, extending from the first perforated scale to the end of the caudal filament. Superior medial stripe wide, two scales deep, light brown color, extending from the posterior end of the gas bladder to a point approximately threefourths of the body length from the snout. Inferior medial stripe with varying width, dark, blackish, originating near anus and extending to posterior end of the anal fin. Stripe along anal-fin base narrow, one to one and a half scales wide, dark brown color, extending along the edge of the anal fin. Pectoral fin hyaline with a few concentrated chromatophores around the base of the fin and in large individuals all along the fin. Anal fin hyaline, with some cases of few dispersed chromatophores along the base. Humeral spot present, not very dark, marking the beginning of the lateral-line stripe. Nape dark.

Geographic distribution. Eigenmannia zenuensis is known from the lower Magdalena, Cauca, and San Jorge rivers basins in Colombia ( Fig. 7 ). This confluence area in the lowlands constitutes the most significant wetland in northern South America, known locally as the “Depresión Momoposina.”

Etymology. The specific epithet “ zenuensis ” is assigned in honor to the Amerindian Colombian tribe Zenú .

Figures

FIGURE 7 | Map illustrating the known geographic distribution of Eigenmannia camposi (circles), E. zenuensis (squares), and E. magoi (triangles). Red symbols indicate type localities.

FIGURE 9 | Holotype CZUT 11030 for Eigenmannia zenuensis, scale bar 1 cm.