taxonID	type	description	language	source
986287FDFFC2CC40FCC6FEB1FC94FDC8.taxon	description	urn: lsid: zoobank. org: act: 440 E 8 BD 9 - 0603 - 4866 - BCB 7 - 3 A 54465 F 6 B 78 (Figs. 2 – 6; Tabs. 1, 2)	en	Hartmann, Caroline, Wingert, Juliana M., Angrizani, Rafael C., Malabarba, Luiz R. (2026): An unexpected discovery of a new species of Jenynsia (Cyprinodontiformes: Anablepidae). Neotropical Ichthyology (e 250128) 24 (1): 3773-3803, DOI: 10.1590/1982-0224-2025-0128, URL: https://doi.org/10.1590/1982-0224-2025-0128
986287FDFFC2CC40FCC6FEB1FC94FDC8.taxon	materials_examined	Holotype. UFRGS 29990, 56.7 mm SL, TEC 2867, Brazil, Rio Grande do Sul, Itati, arroio Carvalho, tributary of rio Três Forquilhas, rio Tramandaí system, 29 ° 23 ' 25 " S 50 ° 11 ' 02 " W, 6 Jun 2012, L. R. Malabarba, J. Ferrer, L. Artioli, P. Neto-Carvalho. Paratypes. All from Brazil, Rio Grande do Sul. UFRGS 16534, 1, 52.5 – 66.7 mm SL, TEC 2867, collected with the holotype. MCP 10779, 33, 27.4 – 68.2 mm SL, 2 c & s, 56.5 – 62.0 mm SL, Torres, creek tributary of rio Três Forquilhas, Chapéu, 29 ° 32 ' 00 " S 50 ° 05 ' 00 " W, 25 May 1986, C. A. Lucena, L. R. Malabarba & R. E. Reis. MCP 25663, 14, 34.6 – 63.7 mm SL, Itati, arroio Carvalho, tributary of rio Três Forquilhas, 29 ° 23 ' 00 " S 50 ° 12 ' 00 " W, 21 Mar 2000, W. Bruschi Jr. & G. Vinciprova. MCP 25292, 41, 20.7 – 66.9 mm SL, Terra de Areia, rio Três Pinheiros, 29 ° 31 ' 36 " S 50 ° 06 ' 21 " W, 29 Dez 1999, L. R. Malabarba, J. P. Silva, V. A. Bertaco & T. Borges. MCP 25306, 19, 21.4 – 66.9 mm SL, Terra de Areia, creek between Terra de Areia and Itati, 29 ° 31 ' 01 " S 50 ° 06 ' 40 " W, 29 Dec 1999, L. R. Malabarba, J. P. Silva, V. A. Bertaco & T. Borges. UFRGS 2995, 15, 32.4 – 73.2 mm SL, 2 c & s, 52.3 – 61.1 mm SL, Três Forquilhas, rio Três Forquilhas, 29 ° 32 ' 00 " S 50 ° 05 ' 00 " W, 20 Aug 1983, Ichthyology UFRGS team. UFRGS 4994, 2, 41.4 – 66.6 mm SL, 2 c & s, 1 male, 45.0 mm SL, 1 female, 59.4 mm SL, Maquiné, rio Maquiné, 29 ° 39 ' 07 " S 50 ° 12 ' 29 " W, 25 Jan 2001, L. R. Malabarba, J. A. Anza, V. A. Bertaco & T. Hasper. UFRGS 6308, 1, 67.7 mm SL, Três Forquilhas, rio Três Forquilhas at Vila Boa União, 29 ° 28 ' 17.58 " S 50 ° 07 ' 00.33 " W, 26 Aug 2003, J. Anza, P. Colombo & L. Fusinatto. UFRGS 12586, 7, 38.5 – 66.7 mm SL, TEC 1262, Itati, arroio do Padre, 29 ° 29 ' 09.5 " S 50 ° 07 ' 15.6 " W, 31 Mar 2010, J. Ferrer, T. Hasper, K. Vogel & F. Weiss. UFRGS 16503, 129, 20.9 – 68.2 mm SL, TEC 2831, 10, 42.0 – 64.4 mm SL, Itati, mouth of arroio da Barra into arroio Bananeiras, 29 ° 25 ' 37 " S 50 ° 10 ' 49 " W, 6 Jun 2012, L. R. Malabarba, J. Ferrer, L. Artioli & P. Neto-Carvalho. UFRGS 17821, 9, 18.0 – 63.6 mm SL, TEC 3502, Maquiné, Barra do Ouro, 29 ° 34 ' 13.6 " S 50 ° 16 ' 49 " W, 2 Jun 2013, J. P. Miranda Santos. UFRGS 18439, 1, 24.9 mm SL, TEC 3832, Maquiné, RS- 484, tributary of rio Maquiné, 29 ° 34 ' 14.3 " S 50 ° 16 ' 49.9 " W, 29 Jan 2014, L. R. Malabarba et al. UFRGS 18442, 1, 61.0 mm SL, TEC 3835, Maquiné, RS- 484, tributary of rio Maquiné, 29 ° 31 ' 26.04 " S 50 ° 18 ' 56.6 " W, 29 Jan 2014, L. R. Malabarba et al. UFRGS 18447, 11, 18.2 – 69.4 mm SL, TEC 3840, Maquiné, RS- 484, tributary of rio Maquiné, 29 ° 31 ' 26.04 " S 50 ° 18 ' 56.6 " W, 29 Jan 2014, L. R. Malabarba et al. UFRGS 18466, 4, 43.7 – 57.1 mm SL, TEC 3859, Maquiné, RS- 484, tributary of rio Maquiné, 29 ° 40 ' 08 " S 50 ° 12 ' 24 " W, 29 Jan 2014, L. R. Malabarba et al. UFRGS 21403, 9, 49.7 – 80.0 mm SL, TEC 6427, and TEC 6453, Itati, rio do Padre, 29 ° 29 ' 27.4 " S 50 ° 08 ' 49 " W, 27 Jan 2016, R. Angrizani, J. Wingert, J. Ferrer & F. Kuhn. UFRGS 26517, 9, 35.7 – 54.7 mm SL, Maquiné, rio Maquiné, 29 ° 39 ' 08 " S 50 ° 12 ' 34 " W, 27 Oct 2018, UFRGS students.	en	Hartmann, Caroline, Wingert, Juliana M., Angrizani, Rafael C., Malabarba, Luiz R. (2026): An unexpected discovery of a new species of Jenynsia (Cyprinodontiformes: Anablepidae). Neotropical Ichthyology (e 250128) 24 (1): 3773-3803, DOI: 10.1590/1982-0224-2025-0128, URL: https://doi.org/10.1590/1982-0224-2025-0128
986287FDFFC2CC40FCC6FEB1FC94FDC8.taxon	diagnosis	Diagnosis. Jenynsia aurea belongs to the subgenus Plesiojenynsia and is diagnosed from the species of the subgenus Jenynsia based on possession of a tubular gonopodium with a short fourth anal-fin ray, less than two-thirds length of ray three. Jenynsia aurea is distinguished from J. diphyes, J. eigenmanni, and J. eirmostigma by the possession of a single midlateral stripe in adults (Figs. 3 – 4; vs. discontinuous midlateral and dorsolateral stripes formed by a series of blotches on the body in J. diphyes, and three distinct and discontinuous lateral stripes in J. eigenmanni and J. eirmostigma). Jenynsia aurea (except in juveniles) differs from J. unitaenia by lacking dorsolateral or ventrolateral chevron marks associated to the midlateral stripe (Figs. 3 – 4; vs. presence of dorsolateral or ventrolateral chevron marks in J. unitaenia, Fig. 7). Jenynsia aurea is distinguished from J. eigenmanni, J. eirmostigma, and J. weitzmani by the presence of 13 to 15 gill rakers on ventral limb of first gill arch (in 2 c & s specimens) (vs. fewer than 13 gill rakers). Jenynsia aurea is distinguished from J. diphyes, J. eigenmanni, J. eirmostigma, and J. weitzmani by the presence of the first mandibular-canal pore (pore W; vs. absence).	en	Hartmann, Caroline, Wingert, Juliana M., Angrizani, Rafael C., Malabarba, Luiz R. (2026): An unexpected discovery of a new species of Jenynsia (Cyprinodontiformes: Anablepidae). Neotropical Ichthyology (e 250128) 24 (1): 3773-3803, DOI: 10.1590/1982-0224-2025-0128, URL: https://doi.org/10.1590/1982-0224-2025-0128
986287FDFFC2CC40FCC6FEB1FC94FDC8.taxon	description	Description. Morphometric data in Tabs. 1 (males) and 2 (females). Body terete and laterally compressed posteriorly. Greatest body depth at pelvic-fin origin or anterior to that point in pregnant females. Head relatively short and pointed. Mouth terminal to slightly subterminal in large specimens, clearly displaced ventrally when protracted (Figs. 4 A, B). Dorsal-fin origin at a vertical between pelvic and anal fins. Largest female (73.2 mm SL) and largest male (67.7 mm SL). Adult males with tubular gonopodium composed of the anal fin with distal tip directed laterally, dextral or sinistral. Intromittent organ supported by eight anal-fin rays, with posterior one or two anal-fin rays not forming the gonopodium. Females with median urogenital opening, lacking flaps or swelling areas. Head-squamation pattern E type. Supraorbital-pore pattern represented by three disjunct canals (1, 2 a; 2 b, 3, 4 a; 4 b, 5, 6, 7). Preopercular canal with seven pores. Mandibular canal with five pores (W, X, Va, Vb, Z). Infraorbital canal with four pores. Teeth on dentary and premaxilla tricuspid, with distal tip expanded and twice wider than its mid length (Fig. 5). Ascending process of premaxilla in adults present and prominent. Dorsal-fin rays 9 [1], 10 [22], 11 [19] or 12 * [1]. Pectoral-fin rays 15 [2], 16 * [29], 17 [8], or 18 [1]. Pelvic-fin rays 6 * [34], or 7 [6]. Anal-fin rays (females) 9 [10], 10 [2]; (males) 9 [1], 10 [1]. Principal caudal-fin rays 16 [4], 17 [12], or 18 * [28]. Predorsal scales 14 [8], 15 * [20], or 16 [12]. L 1 scales 8 [3], 9 [6], 10 * [4], 11 [8], 12 [7], 13 [2], or 14 [1]. L 2 scales 20 [1], 21 [2], 22 * [12], 23 [14], 24 [6], 25 [1]. Scales around caudal peduncle 13 [3], 14 * [18], 15 [9], or 16 [3]. Gill rakers on ventral arm of first gill arch 13 [1], 15 [1]. Total vertebrae 33 [3], 34 [3], abdominal vertebrae 14 [4], 15 [2], caudal vertebrae 18 [1], 19 [3], 20 [2]. Coloration in alcohol. Body background color grading from brown dorsally to pale yellow on ventral surface (Figs. 4 B, D, 6). Black chromatophores distribution differs between small and mature specimens. Specimens from 20 mm SL up to about 40 mm SL show irregular reticulated black pattern bordering body scales, with lighter, non-reticulate areas more numerous in smaller than in larger specimens, and distributed mostly on caudal peduncle and lower half of body (Fig. 6). A black stripe with irregular borders and sometimes interrupted along its length is present from the posterior edge of the operculum to caudal fin (Fig. 6). Large males and females (nearly 45 mm SL and larger) show a more regular reticulate pattern that is progressively lighter ventrally, with dark chromatophores on scale margin, lacking lighter non-reticulate areas. A continuous black stripe is also present, without interruptions and with smooth dorsal and ventral margins (Figs. 4 B, D). Some specimens show the black stripe bending ventrally near the caudal fin (Figs. 3 A, D). Specimens with intense black pigmentation on scales may turn black above the belly region (Figs. 3 A, B). Mature females with a genital spot. Head brown dorsally grading to pale yellow ventrally. Fins unpigmented except for a few dark chromatophores bordering the rays in dorsal fin, caudal fin and dorsal part of pectoral fin. Coloration in life. Color patterns vary according to body size and sex, with intense golden reflections and less discernible black pigments in mature males (usually more than 55 mm SL; Figs. 2, 4 A) than in females or small specimens (Figs. 3 C, D, 4 C, 6). Mature males are golden brown on the back and upper half of the body and head; golden yellow on ventral half of body and on the pectoral, dorsal, anal and caudal fins; hyaline on pelvic fins; usually white on ventral surface of head and body (Figs. 3 A, 4 A), but the holotype is golden yellow also on ventral portions of head and body (Fig. 2). Females are dark brown on the back and upper half of the body and head; golden yellow on ventral half of head and body; all fins hyaline; white on ventral surface of head and body (Figs. 3 B, 4 D). Specimens smaller than 50 mm SL have the overall body color light brown on upper half of head and body, light brown on ventral half of body and white on ventral surface of head and belly (Fig. 3 C). All specimens show a continuous lateral stripe, hardly discernible in fully colored males whose scale row on the lateral stripe show light reflections over a dark brown stripe (Figs. 2, 4 A). Black marks as described in alcohol preserved specimens.	en	Hartmann, Caroline, Wingert, Juliana M., Angrizani, Rafael C., Malabarba, Luiz R. (2026): An unexpected discovery of a new species of Jenynsia (Cyprinodontiformes: Anablepidae). Neotropical Ichthyology (e 250128) 24 (1): 3773-3803, DOI: 10.1590/1982-0224-2025-0128, URL: https://doi.org/10.1590/1982-0224-2025-0128
986287FDFFC2CC40FCC6FEB1FC94FDC8.taxon	distribution	Geographical distribution. The species is found in the rio Maquiné, rio Três Forquilhas, rio Tramandaí system, and their tributaries in the valleys of the Serra Geral Formation (Fig. 1).	en	Hartmann, Caroline, Wingert, Juliana M., Angrizani, Rafael C., Malabarba, Luiz R. (2026): An unexpected discovery of a new species of Jenynsia (Cyprinodontiformes: Anablepidae). Neotropical Ichthyology (e 250128) 24 (1): 3773-3803, DOI: 10.1590/1982-0224-2025-0128, URL: https://doi.org/10.1590/1982-0224-2025-0128
986287FDFFC2CC40FCC6FEB1FC94FDC8.taxon	etymology	Etymology. The name “ aurea " comes from Latin “ aurum " meaning golden, in a reference to the color in life, especially of mature males. An adjective.	en	Hartmann, Caroline, Wingert, Juliana M., Angrizani, Rafael C., Malabarba, Luiz R. (2026): An unexpected discovery of a new species of Jenynsia (Cyprinodontiformes: Anablepidae). Neotropical Ichthyology (e 250128) 24 (1): 3773-3803, DOI: 10.1590/1982-0224-2025-0128, URL: https://doi.org/10.1590/1982-0224-2025-0128
986287FDFFC2CC40FCC6FEB1FC94FDC8.taxon	conservation	Conservation status. The new species is widely distributed in the rio Maquiné and rio Três Forquilhas and no specific threat can be assigned to this species. According to the International Union for Conservation of Nature (IUCN, 2024) categories and criteria, Jenynsia aurea would be classified as Least Concern (LC).	en	Hartmann, Caroline, Wingert, Juliana M., Angrizani, Rafael C., Malabarba, Luiz R. (2026): An unexpected discovery of a new species of Jenynsia (Cyprinodontiformes: Anablepidae). Neotropical Ichthyology (e 250128) 24 (1): 3773-3803, DOI: 10.1590/1982-0224-2025-0128, URL: https://doi.org/10.1590/1982-0224-2025-0128
986287FDFFC2CC40FCC6FEB1FC94FDC8.taxon	discussion	Molecular analysis. A total of 664 base pairs were aligned for the mtDNA sequences of 27 samples for the COI gene. A total of 26 polymorphic sites were found, resulting in 16 haplotypes and a haplotypic diversity hd = 0.92. The haplotype network (Fig. 7) of the species available of the subgenus Plesiojenynsia recovered four genetically distinct groups. Two correspond to Jenynsia eirmostigma and J. weitzmani. The MP-AR group corresponds to J. unitaenia and the MQ-TF group corresponds to J. aurea. The AMOVA test showed a high genetic differentiation between the analyzed populations (Fst = 0.85), demonstrating that 85 % of genetic differentiation is between populations and only 15 % is within populations. This value was very high when we analyzed the variance between the northern (MP-AR) and southern (MQ-TF) groups (Fst = 0.88), corroborating the results of the haplotype network. Bayesian inference analyses recovered similar results. The COI gene tree recovered a topology similar to the groups recovered in the COI haplotype network. Both MP-AR and MQ-TF clades proved to be monophyletic and sister groups, with high support values (PP = 1) (Fig. 8). MQ and TF also form separate clades with high support values (PP = 1) between the two populations assigned herein to J. aurea. The species tree generated presented the same topology as the previous results. Strict molecular clock analysis showed that the clade Jenynsia unitaenia + J. aurea dates back to at least 1.2 Ma, when the two species diverged. Within J. unitaenia, MP and AR populations diverged 0.4 Ma ago. Within J. aurea MQ and TF populations diverged 0.2 Ma ago (Fig. 9). Morphological comparison between J. aurea and J. unitaenia. The analysis of morphometric and meristic characters does not allow a diagnosis between J. aurea (MQ and TF) and J. unitaenia (MP and AR). A morphometric difference between the two species was observed in head depth of females (Tab. 2) that ranges from 42.5 to 50.0 % of head length (mean = 46.8) in J. aurea and 47.8 – 55.0 (mean = 51.1) in J. unitaenia, with a large overlap. Males of J. aurea also show a more depressed head (head depth 43.8 – 48.8 % of head length, mean = 46.6 %) than J. unitaenia (45.0 – 51.3 %, mean = 47.9 %), but the difference in the mean is smaller than in females (Tab. 1). Populations from MQ and TF, corresponding to J. aurea, show jaw teeth slender, spaced and more constricted at their mid length (Fig. 5), while those from MP and AR, corresponding to J. unitaenia, show teeth more robust and less spaced (Fig. 10). Populations from MQ and TF, corresponding to J. aurea (Figs. 2 – 4), differ from those of MP and AR, corresponding to J. unitaenia (Fig. 11), in the color pattern. Both populations of J. unitaenia show a series of irregular chevron marks along the dorsal and ventrolateral margins of the midlateral stripe (Fig. 11), while populations of J. aurea from MQ and TF lack such pattern (Figs. 2 – 4). The chevron marks along the dorsal and ventrolateral margins of the midlateral stripe are observed in juveniles of both species (Fig. 6). There is one lot of Jenynsia unitaenia listed by Ghedotti, Weitzman (1995) from a locality not belonging to MP and AR drainages: the paratypes of USNM 326104 from Rio Grande do Sul state, Terra de Areia municipality, rio Três Pinheiros, belonging to TF drainage. All specimens we have from TF drainage belong to J. aurea, including one lot designated herein as paratypes of J. aurea (MCP 25292), also collected in the rio Três Pinheiros. Once the paratypes of USNM 326104 are juveniles (3 specimens, 24.4 – 28.3 mm SL), and juveniles of J. aurea (Fig. 6) show irregular chevron marks along the dorsal and ventrolateral margins of the midlateral stripe similar to that found in J. unitaenia, we consider this lot of J. unitaenia paratypes as belonging to J. aurea. Character coding of Jenynsia unitaenia given by Ghedotti, Weitzman (1995) does not seems to include data from specimens of J. aurea misidentified as J. unitaenia, once paratypes of USNM 326104 do not include cleared and stained specimens for osteological analyses. We further checked characters coded to J. unitaenia by Amorim (2018) and they actually correspond to specimens of J. unitaenia examined herein. Jenynsia aurea differs from J. unitaenia in one character that further diagnosis the two species (numbered according to Amorim, 2018; Aguilera et al., 2019: S 1 tab.). The anterior cleft in anguloarticular is large in J. unitaenia (Fig. 10) extending posteriorly beyond posterior border of Meckel's cartilage (ch. 19, state 0), and small in J. aurea (Fig. 5), not extending posteriorly beyond posterior border of Meckel's cartilage (ch. 19, state 1). Differences in coding two additional characters are related to polymorphism observed in each species and are not diagnostic. The ossified process on ventrolateral margin of basioccipital at attachment of Baudelot's ligament in adults is polymorphic in J. unitaenia (ch. 11, state 0 - absent and state 1 - present) and present in J. aurea (ch. 11, state 1). The number of anal-fin rays is 10 in J. unitaenia (ch. 40, state 2), but polymorphic in J. aurea, ranging from 9 to 10 (ch. 40, states 2 and 3).	en	Hartmann, Caroline, Wingert, Juliana M., Angrizani, Rafael C., Malabarba, Luiz R. (2026): An unexpected discovery of a new species of Jenynsia (Cyprinodontiformes: Anablepidae). Neotropical Ichthyology (e 250128) 24 (1): 3773-3803, DOI: 10.1590/1982-0224-2025-0128, URL: https://doi.org/10.1590/1982-0224-2025-0128
