A new species of Farlowella (Siluriformes: Loricariidae) from the upper Bermejo River, La Plata River basin, northwestern Argentina Author Terán, Guillermo E. Author Ballen, Gustavo A. Author Alonso, Felipe Author Aguilera, Gastón Author Mirande, J. Marcos text Neotropical Ichthyology 2019 2019-06-27 17 2 1 7 journal article 10.1590/1982-0224-20180114 35edb1bb-d2a1-4824-87af-8c9e6e7349bf 1982-0224 3649852 2ACE7A43-17E6-4206-83F2-62E56B1031D3 Farlowella azpelicuetae , new species urn:lsid:zoobank.org:act: E8176E2F-F1B4-4998-A5BC- AC11B9C151ED Figs. 1-2 , Tab. 2 . Holotype : CI-FML 7277, 142.3 mm SL. Argentina , Salta , Bermejo River , La Plata River basin, 23°10ʹ56ʺS , 64°12ʹ18.36ʺW , ca . 300 m above sea level (asl). 26 Sep 2015 . G.E. Terán , G. Aguilera , F. Alonso and J.M. Mirande. Paratypes . CI-FML 7265, 7 (2 c,s), 64.2- 193.8 mm SL; IBIGEO-I 453 6, 69.3-77.5 mm SL ; MZUSP 123935 , 1 , 83.3 mm SL. Collected with the holotype . CI-FML 7274, 2, 72.3-178.7 mm SL ; MZUSP 123936 , 2 , 169.0- 81.4 mm SL. Argentina , Salta , Bermejo River basin, 23°10ʹ56ʺS , 064°12ʹ18.36ʺW , ca . 300 m asl . 20 Sep 2016 . G.E. Terán , G. Aguilera , F. Alonso and J. M. Mirande. CI-FML 7266, 1, 140.9 mm SL; CFA-IC-8845, 2, 129.7- 130.9 mm SL. Argentina , Jujuy , San Francisco River , Bermejo River basin, 23°50’27.08”S , 64°37’24.70”W , ca . 370 m asl . 30 Sep 2016 . G.E. Terán and G. Aguilera . Diagnosis. Farlowella azpelicuetae differs from most congeners, except F. altocorpus , F. gianetii , F. gracilis , F. hasemani , F. isbrueckeri , F. jauruensis , F. nattereri , and F. odontotumulus , by the presence of five rows on lateral plate series of body ( vs . four). Farlowella azpelicuetae differs from F. gracilis , F. hasemani , F. isbrueckeri , F. nattereri , and F. odontotumulus by having proportionally-shorter snoutmouth length (less than 50% HL vs . more than 50% HL). The new species differs from F. jauruensis and F. gianetii by its marbled coloration pattern of snout ( vs. snout completely dark and snout darkly pigmented only laterally, respectively). Farlowella azpelicuetae differs from F. altocorpus by having a continuous half-moon pigmentation pattern on the caudal fin ( vs . discontinuous half-moon shaped pattern) and by the shorter predorsal length (37.8-41.8 % SL vs. 43.7-45.6% SL). The new species can be further distinguished by the presence of three rows of abdominal plates ( vs. two in F. acus , F. amazonum , F.colombiensis , F.henriquei , F.martini , F.rugosa , F. venezuelensis , F. vittata , and F. yarigui and an incomplete median disjunct row of abdominal plates in F. mitoupibo ). Additionally, F. azpelicuetae differs from F. hahni , F. knerii , F. oxyrryncha , F. reticulata , and F. schreitmuelleri by having irregular dark brown blotches on the snout ( vs . a reticulated pattern formed by the dark pigmentation of the border of the bony plates in the head); from F. curtirostra and F. taphorni by the absence of breeding odontodes on side of head and presence of a long and slender snout ( vs. presence of breeding odontodes on sides of the head and presence of a short and broad snout). The new species also differs from F. hahni , F. mariaelenae , F. oxyrryncha , F. paraguayensis , and F. smithi by having a continuous half-moon pigmentation pattern on the caudal fin ( vs. caudal pigment restricted to the dorsal lobe in F. hahni , F. oxyrryncha , and F. smithi and discontinuous pattern with dark stripe in upper lobe of caudal fin broad and larger than stripe in lower caudal lobe in F. mariaelenae and F. paraguayensis ). Additionally, the new species can be distinguished from F. gianetii by having i,11,i or i,12,i caudal-fin rays ( vs. i,10,i), F. gracillis by the diamond-shaped plates in the second row of lateral plate series ( vs. hexagonal plates), from F. isbrueckeri by presenting the ventromedian row of anterior plates keeled and the marbled coloration pattern on snout ( vs. row unkeeled and snout entirely dark), from F. jauruensis by having i,5 pelvic-fin rays ( vs. i,4), from F. nattereri by first anal- and dorsal-fin rays not entirely darkly pigmented ( vs. entirely pigmented), and from F. odontotumulus by the presence of spots on fins ( vs. spines and rays lacking spots). Description. Morphometric data for holotype and paratypes presented in Tab. 2 . Body elongate, slender and cylindrical in transversal section, dorsoventrally depressed. Greatest body depth and width at opercular region. Head slightly depressed in lateral view, body trunk cylindrical, caudal peduncle depressed. Dorsal profile of head concave from snout tip to anterior margin of nares, relatively straight from that point to posterior margin of parieto-supraoccipital, and then slightly concave until dorsal-fin origin. Body profile straight from last dorsal-fin ray to caudal fin. Ventral profile slightly straight from tip of snout to pectoral girdle, straight from that point to anal-fin insertion; straight from the terminus of anal fin to anteriormost ventral caudal-fin plate. Body completely covered with bony plates except for snout tip, gular region and oval region surrounding urogenital area. Snout short, papillae absent. Preorbital ridge present. Anterior and posterior nares of similar size, with dermal flap separating both openings. Orbit dorsolateral, not visible in ventral view; iris operculum present. Sixth infraorbital present. Dorsal surface of head with longitudinal keel on supraoccipital bone; compound pterotic ornamented with reticulate pattern of perforations. Mouth ovoid, lower lip longer than upper lip; wide oval papillae on upper lip and round papillae on lower lip; decreasing in size from oral aperture to lip margin; lip margin papillose. Few platelets anterior to lip. Each premaxilla with 21(1), 22(4), 23(1), 24(4), 25(4), 28(1), 29(1), 33(3), or 34*(1) bicuspid teeth. Each dentary with 20(2), 21(3), 22(3), 23(3), 24(1), 25(4), 27(1), 29(1), 30*(1), or 33(1) bicuspid teeth; premaxilla wider than dentary. Buccal papillae present. Ventral surface of head completely covered by platelets. Two maxillary barbels small and projecting slightly from mouth margin. Five lateral plate rows on anterior portion of body, dorsal series with 30(1), 31*(12), 32 (5), 33(1), or 34(1) plates; dorsomedian series with 7*(9), 8(7), or 9(4) plates; median series with 7(1), 8*(6), 9(6), 10(5), or 11(2) plates; dosomedian+median series with 4(1), 5(5), 6*(7), or 7(7) plates; ventromedian series with 15*(7) or 16(13) plates; ventral series with 32 (2), 33*(6), 34(6), 35(5), or 36(1) plates; and coalescent series with 18(12), 19*(6), or 20(2) plates. Pectoral-fin rays i,6*(20), posterior border straight, leading ray longest and thicker than branched rays; pelvicfin rays i,5*(20), posterior margin slightly curved; dorsal-fin rays i,6*(20). Anal-fin rays i,5*(20), similar in size and shape to dorsal fin. Adipose fin absent. Caudal-fin rays i,11,i(2), i,12,i*(18), dorsal and ventral lobes similar in size; the principal caudal-fin ray in each lobe bears a filament. Breeding odontodes were not found in the analyzed specimens. Color in alcohol. Background coloration light brown, with one dark brown lateral stripe on each side, that runs from snout to end of dorsal fin, leaving a central light brown area ( Fig. 1 ). Snout with dark brown marbled pattern in dorsal view ( Fig. 2a ), more uniform and darker in the ventral and lateral portions of head and lighter on the dorsal region. Ventral body region light brown with diffuse scattered pigmentation. Fins with dark brown blotches on rays and slightly hyaline on membranes. Caudal fin with a dark marking forming a continuous crescentic half-moon pigmentation pattern ( Fig. 2b ). Color in life. Overall coloration of specimens in life similar to specimens after fixation except for the brighter yellowish background of the body ( Fig. 2c ). Tab. 2. Morphometric data of Farlowella azpelicuetae , sp. n. (n=20). SD, standard deviation. Range includes the holotype.

Holotype	Range	Mean	SD
Standard length (SL)	142.4	64.2-193.9
Percentage of Standard length
Head length (HL)	24.9	22.8-25.0	23.8	0.8
Body depth at dorsal- fin origin	5.9	5.4-6.4	5.9	0.3
Body width at dorsal- fin origin	6.6	6.4-8.1	7.0	0.4
Body width at anal- fin origin	7.0	5.5-7.6	6.5	0.5
Predorsal length	41.4	37.8-41.8	39.7	1.1
Postdorsal length	54.2	51.4-57.6	54.7	1.6
Postanal length	54.6	50.0-56.8	53.9	1.6
Caudal peduncle depth	1.5	1.0-1.5	1.2	0.1
Dorsal-spine length	16.9	15.4-17.2	16.3	0.5
Pectoral-spine length	13.8	12.5-14.2	13.3	0.5
Pelvic-spine length	8.9	7.7-9.0	8.4	0.4
Anal-spine length	16.1	14.4-16.1	15.2	0.5
Percentage of Head Length
Snout length	73.8	65.3-74.3	69.6	2.7
Snout-mouth length	41.3	26.9-43.5	34.3	5.2
Eye diameter	6.6	6.3-10.0	7.7	1.1
Interorbital width	19.8	19.6-23.8	21.3	1.1
Head width	36.9	34.7-43.0	38.3	2.3
Head depth	22.8	21.8-28.0	24.5	1.9
Proportion characters sensu Retzer, Page (1996)
Snout-mouth length / pectoral-spine length	74.4	48.9-77.8	61.3	9.6
Snout-mouth length / HL	41.3	26.9-43.5	34.3	5.2
HL / Snout-mouth length	242.3	229.8-371.3	298.1	44.1
Body depth / pelvic-spine length	65.9	63.1-78.9	70.8	4.4
Pectoral spine length / snout-mouth length	134.5	128.6-204.6	166.8	25.7
Snout-mouth length / interorbital width	208.1	121.5-218.2	162.2	31.2
Body width / snout-mouth length	64.4	64.4-111.9	87.3	14.2

Fig. 1. Farlowella azpelicuetae , holotype, Argentina, Salta, Bermejo River, La Plata River basin. CI-FML 7277, 142.4 mm SL, a. lateral, b. dorsal, and c. ventral views. Geographic distribution. Farllowella azpelicuetae is distributed in the upper Bermejo River basin, La Plata basin, provinces of Salta and Jujuy in the Yungas region, northwestern Argentina ( Fig. 3 ). Ecological notes. Specimens were collected at altitudes ranging from 310 to 450 masl in the main channel of the Bermejo ( Fig. 4 ) and San Francisco Rivers, associated with wood drift debris on the margins. No specimens of this species were captured in streams, or small courses of water sampled in the area. Etymology. The species is named azpelicuetae after Dr. María de las Mercedes Azpelicueta, in recognition of her prominent contributions to ichthyology, especially to the systematics of Argentinian fishes. She described numerous species and was essential to the formation of subsequent generations of freshwater fish systematists in Argentina . A matronym in genitive case. Conservation status. Considering that no major threats to the species were detected in the area of distribution, the conservation status of Farlowella azpelicuetae may be classified as having Least Concern (LC), according to the International Union for Conservation of Nature (IUCN) categories and criteria (IUCN, 2017). Comparative material . Most of the comparative material was listed in Ballen, Mojica (2014) , Ballen et al . (2016a , 2016b ). Additional material: Farlowella hahni : Argentina , Province of Corrientes , Paraná River, CI-FML 5419,1, 43.9 mm SL; CI-FML 7504, 3, 74.8-114.2 mm SL . Fig. 2. Farlowella azpelicuetae , paratype, CI-FML 7265, 193.9 mm SL. a . detail of the coloration of the snout; b. coloration pattern of caudal fin; c . coloration of live specimen. Fig. 3. Map of northwestern Argentina, showing the distribution of Farlowella azpelicuetae . Red star represents the type locality. Azpelicueta MM , Koerber S . , 1937. Hist Nat (Buenos Aires). 2014 ; 4 ( 2 ): 95-99 . Ballen GA , Mojica JI . . Zootaxa. 2014 ; 3765 ( 2 ): 134-42 . Available from: http://dx.doi.org/10.11646/ zootaxa.3765.2.2 Fig. 4. Type locality of Farlowella azpelicuetae . Bermejo River at 23°10ʹ56ʺS, 64°12ʹ18.36ʺW, La Plata River basin, Salta, Argentina. September 2016. Ballen GA , Pastana MNL , Peixoto LAW . . Neotrop Ichthyol. 2016 a; 14 ( 3 ):e 160046 . Available from: http://dx.doi. org/10.1590/1982-0224-20160046 Farlowella azpelicuetae is assigned to the Farlowella nattereri group sensu Ballen et al . (2016a) (see Tab. 1 ), because it exhibits the following characteristics: five lateral plates on the anterior portion of the body, three abdominal plate series, and diamond shaped median plates. Ballen GA , Urbano-BonillaA , Zamudio JE . . Ichthyol Explor Freshw. 2016 b; 27 ( 4 ): 325-32 . The new taxon is the second species of the genus Farlowella known to Argentina after F. hahni , distributed in the lower Paraná and Paraguay Rivers. A third species mentioned for Argentina is F. amazonum . However, the presence of this species has not been confirmed and it is only based on the hypothesized locality of the holotype of F. paranaense (synonym of F. amazonum ), after a probable labelling error by Meinken (see, Azpelicueta, Koerber, 2014 ). Boeseman M . . Zool Verh. 1971 ; 116 : 1-56 . Covain R , Fisch-Muller S . . Zootaxa. 2007 ; 1462 ( 1 ): 1-40 . Available from: https://www.mapress.com/zootaxa/2007f/ zt01462p040.pdf The Bermejo River is one of the greatest hydrographic systems of Argentina and one of the main tributaries of the Rio de la Plata system. According to Hales, Petry (2015) , the Bermejo River basin belongs to the Chaco Ecoregion. This area also includes the drainages of the western Paraguay basin across Bolivia , Paraguay , and Argentina . There are presently more than 150 species of fishes recorded in this ecoregion of which at least 17 are endemic ( Terán et al ., 2016 ). The pace at which description of new taxa is occurring in this region suggests the chance of further discoveries. The outstanding diversity of the area when compared to other drainages in the southernmost portion of the continent renders the Bermejo River basin an important reservoir of biological resources for Argentina . Fernández-Yépez A . . Venezuela. 1972 ; 1 : 1-25 Fricke R , Eschmeyer WN , Van der Laan R . . San Francisco(CA): California Academy of Sciences ; 2019 [cited 2019 May 2 ]. Available from: http://researcharchive. calacademy.org/research/ichthyology/catalog/fishcatmain. asp Fricke R , Eschmeyer WN . . San Francisco (CA): California Academy of Sciences ; 2019 . [cited 2019 Apr 25 ]. Available from: http://researcharchive.calacademy.org/research/ichthyology/ catalog/collections.asp Acknowledgments Financial support was provided by CONICET, Fundación Miguel Lillo, and FONCyT (PICT-2011-0992 and PICT-2016-0275 to JMM and PICT- 2012-2683 to GA). Secretaría de Ambiente of Salta and Jujuy provided the collecting licenses. GAB was funded through a doctoral scholarship and a BEPE internship grant by FAPESP (2014/11558-5 and 2016/02253-1). We thank Fabiana Cancino for the loan of material. This work was benefited by the comments of Priscila Camelier, Rafaela Ota, Sven Kullander and anonymous reviewers. References Discussion