Loricaria nimairaco, Londoño-Burbano & Urbano-Bonilla & Thomas & Britto, 2023

Londoño-Burbano, Alejandro, Urbano-Bonilla, Alexander, Thomas, Matthew R. & Britto, Marcelo R., 2023, A new species of Loricaria (Loricariidae: Loricariinae) from the upper Amazon River basin, Colombia, Neotropical Ichthyology (e 230008) 21 (3), pp. 1-25 : 4-18

publication ID	https://doi.org/ 10.1590/1982-0224-2023-0008
publication LSID	lsid:zoobank.org:pub:DBBC07D8-9148-4961-B6DE-E7C663DCC511
persistent identifier	https://treatment.plazi.org/id/AA6E2D7D-6426-BC33-FCB5-483425392627
treatment provided by	Felipe
scientific name	Loricaria nimairaco
status	sp. nov.

Treatment

Loricaria nimairaco , new species urn:lsid:zoobank.org:act:227B959E-CC92-49D0-B5C9-90783CA57C4F

( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 6A View FIGURE 6 , 7 View FIGURE 7 , 8 View FIGURE 8 , 10 View FIGURE 10 ; Tabs. 1-4)

Holotype. ICN-MHN 24389, 185.8 mm SL, Colombia, Amazonas , Leticia, río Amazonas, 04°13’29”S 69°56’49”W, 26 Oct 2000, M. Arce GoogleMaps .

Paratypes. All from Colombia: ICN-MHN 4492, 6, 115.5– 153.1 mm SL, Amazonas, Leticia, Sistema río Amazonas, Laguna Yahuarcaca, Lago 4, 04°11’17”S 69°57’39”W, 13 Jun 1999; ICN-MHN 5212, 4, 123.9– 154.5 mm SL, Amazonas, Leticia, km 8 via Leticia-Tarapacá, Yaguarcaca Stream, 04°08’05”S 69°56’36”W, 1 Apr 1999, G Aricari; ICN-MHN 6001, 1, 130.8 mm SL, Amazonas, Leticia, río Amazonas, 04°13’29”S 69°56’49”W, 1 Jul 2000, M. Arce & P. Sánchez; ICN-MHN 9150, 1, 141.5 mm SL, Caquetá, La Montañita, Niña María Stream, tributary of Orteguaza River, 01°22’24”N 75°24’02”W; ICN-MHN 6003, 2, 182.0– 182.2 mm SL, same data as holotype; ICN-MHN 9156, 1, 190.9 mm SL, Amazonas, Leticia, sistema río Amazonas, Laguna Yahuarcaca, 04°11’33”S 69°57’28”W, 12 Oct 1999, S. Vejarano; MPUJ 17396, 1, 170.6 mm SL, Putumayo, Puerto Asís, Vereda El Quebradón, río Putumayo, 00°29’43”N 76°21’11”W, 8 Nov 2021, A. Méndez-López, P. Tombé & R. Villota; MPUJ 17397, 1, 155.9 mm SL, Putumayo, Puerto Asís, Vereda Sinaí-Hachapos, Quebrada El Puma, 00°29’48”N 76°22’56”W, 22 Nov 2021, A. Méndez-López, P. Tombé & R. Villota; MPUJ 17398, 1, 104.5 mm SL, Putumayo, Puerto Asís, Vereda Sinaí-Hachapos, Caño Chufiya, 00°29’05”N 76°22’17”W, 26 Aug 2021, A. Méndez-López, P. Tombé & R. Villota; MPUJ 17399, 1, 180.4 mm SL, Putumayo, Puerto Asis, río Putumayo, 00°33’51”N 76°34’31”W, 28 Aug 2021, A. Urbano-Bonilla, A. Méndez-López, G. López Ríos, J. Vásquez, K. Chalial, O. Camacho, R. Villota & W. C. P. Castro; MPUJ 17400, 1, 164.9 mm SL, Putumayo, Puerto Asis, río Putumayo, 00°33’51”N 76°34’31”W, 16 Nov 2021, A. Urbano-Bonilla, A. Méndez-López, G. López Ríos, J. Vásquez, K. Chalial, O. Camacho, R. Villota & W. C. P. Castro; MPUJ 17401, 1, 160.2 mm SL, Putumayo, Villa Garzón, río Guineo, 00°29’22”N 76°31’05”W, 2 Sep 2021, A. Urbano-Bonilla, A. Méndez-López, G. López Ríos, J. Vásquez, K. Chalial, O. Camacho, R. Villota & W. C. P. Castro; MPUJ 17402, 1, 173.1 mm SL, Putumayo, Villa Garzón, río Guineo, 01°01’04”N 76°38’43”W, 1 Mar 2022, A. Urbano-Bonilla, A. Méndez-López, G. López Ríos, J. Vásquez, K. Chalial, O. Camacho, R. Villota & W. C. P. Castro; ROM 107225, 1, 169.6 mm SL, Amazonas, Caquetá, Orteguaza River, 11.4 km SE of Florencia, 01°31’09”N 75°32’19”W, 249 m asl, 7 Aug 2017, N. K. Lujan, A. Ortega-Lara, G. C. Sanchez, C. Conde & V. Meza-Vargas; ROM 107265, 1, 74.8 mm SL, Caquetá, Amazonas River basin, Orteguaza River, 9 km NE of Florencia, 01°39’29”N 75°32’31”W, 272 m asl, 5 Aug 2017, N. K. Lujan, A. Ortega-Lara, G. C. Sanchez, C. Conde & V. Meza-Vargas.

Diagnosis. Loricaria nimairaco can be distinguished from all congeners by the following combination of characters: dorsal portion of head to origin of dorsal fin with uniform black or dark brown coloration or the presence of two longitudinal stripes from tips of the snout to origin of dorsal fin, without transversal bands or spots ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ) (vs. dorsal portion without coloration, with spots, with transversal bars, or with dark transverse bar reaching nares and snout tip; Figs. 3–5 View FIGURE 3 View FIGURE 4 View FIGURE 5 ); abdominal plates tightly joined and completely covering the median abdominal space and pectoral girdle ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ) (vs. loosely joined, isolated or incompletely covering the pectoral girdle, except species from the Loricaria cataphracta group; Fig. 4 View FIGURE 4 ); and by having dorsal and pectoral fins totally black or dark brown, without bands, spots, or blotches ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ) (vs. dorsal and pectoral fins hyaline or with dark bands, spots, or blotches ( Fig. 4 View FIGURE 4 ), except L. simillima ). The new species is morphologically most similar to L. simillima , from which it can be differentiated by counts on total lateral plates 31–33 (modally 32) (vs. 34–35, modally 34); anterior lateral plates 17–18 (modally 18) (vs. 18–22, modally 20); body width at post-cleithral tip (14.3–17.5% SL vs. 10.6–14.7% SL), and presence of a dark vertical band at distal portion of caudal fin occupying less than half of the fin ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ) (vs. presence of a solid dark vertical band in posterior portion of caudal fin occupying almost the entire fin). Loricaria nimairaco can be diagnosed from L. nickeriensis , which is currently reported as present in the Amazon River, Colombia, by having a broad median abdominal space ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ) (vs. abdominal space narrower than width of each adjacent lateral abdominal plate; Fig. 4 View FIGURE 4 ), presence of plates on cleithral region ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ) (vs. absence of plates on cleithral region; Fig. 4 View FIGURE 4 ), post-orbital notch deep and angular ( Fig. 6A View FIGURE 6 ) (vs. post-orbital notch shallow and rounded; Fig. 6B View FIGURE 6 ) and absence of dark blotches on dorsal and ventral portion of body ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ) (vs. presence of dark blotches on dorsal and ventral portion of body; Fig. 4 View FIGURE 4 ).

Description. Measurements are presented in Tab. 1, and general body form is depicted in Figs. 1–2. A View FIGURE 1 View FIGURE 2 medium- to large-sized Loricaria , with the largest examined specimen 190.9 mm SL. Head and body depressed; maximum body depth at dorsal fin origin, widest at cleithrum, and becoming attenuate posteriorly. Ventral profile of body straight. Head triangular in dorsal view, with lateral margin from snout tip to opercle straight; dorsum entirely covered with plates, including tip of snout. Postorbital notch well developed and large.

Upper and lower lip covered by long, simple marginal fringe barbels. Filiform papillae on upper lip cover premaxillary teeth. Lower lip with fewer filaments than observed on upper lip. Rictal barbel long and thin, not reaching gill opening, and without secondary branches. Buccal papillae behind premaxillary teeth broader than filaments on lips and longer than premaxillary teeth. Teeth bilobed and slender; main cusp longer than lateral cusp in both premaxillary and dentary teeth; premaxillary teeth longer than dentary teeth. Premaxillary teeth 3(12) or 4*(11), modally 3, and dentary teeth 5(1), 6(6), 7*(8), 8(3), 9(3) or 10(1), modally 7 (see Tab. 2 for meristic comparisons among congeners).

Abdomen completely covered with small- to medium-sized irregular plates, without any organization in series or rows. Anterior abdominal plates are smaller, almost rounded, and as numerous as central abdominal plates; anterior border of abdominal plates straight to slightly curved, almost reaching the margin of lower lip, and with or without a shallow median notch ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ). Plates absent at pectoral fin insertion. Predorsal region with two closely aligned, well-developed keels, including supraoccipital tip ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ). Three predorsal plates.

Plates in lateral series 31(5), 32*(16) or 33(2). Anterior lateral plates 17(1) or 18*(22) with well-developed keels, with upper and lower series separated. Posterior lateral plates 13(5), 14*(16), 15(1) or 16(1) with series of keels almost joined. Post-anal plates 20(9) or 21*(14). Thoracic plates 8(13) or 9*(10), elongated, and differentiated from those on the rest of abdomen.

Dorsal-fin rays I,7, spine and two first branched rays longest when adpressed; posterior margin of fin straight when extended. Pectoral-fin rays I,6; posterior margin of pectoral fin slightly concave when extended, with spine and first branched ray longer than other rays; most distal tip reaching to almost half the length of pelvic fin when adpressed. Pelvic-fin rays i,5; first ray prolonged, longer than branched rays; posterior margin of fin straight when extended. Anal-fin rays i,5; anal-fin origin is vertically aligned with dorsal fin insertion; posterior margin of fin straight when extended. Principal caudal-fin rays i,10,i; distal margin of caudal fin concave, with upper and lower rays thickened; upper ray is produced into a long trailing filament, which was broken in most specimens examined.

Coloration in alcohol. Ground color tan to dark brown on dorsum and lateral surfaces; ventral unplated surfaces pale; ventral plated surfaces dark yellow; sides of caudal peduncle with subtle dark spots. Dorsum of head and trunk, extending to three or four plates along the dorsal-fin base, dark brown, without spots or bands ( Fig. 1 View FIGURE 1 ); or, with two longitudinal stripes from tips of the snout to origin of dorsal fin, without transversal bands or spots ( Fig. 2 View FIGURE 2 ). Dorsum of trunk posterior to dorsal-fin insertion marked with three or four dark brown transverse bands: just posterior to end of base of dorsal fin, the following band about five plates posterior to the first one, following band about four plates posterior from it, and the last one not reaching caudal-fin origin ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ). Sides of head anterior to opercular opening dark, same as coloration on dorsal portion of head.

Dorsal and pectoral fins entirely black or dark brown, without spots or bands ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ). Pelvic fins either entirely black or dark brown, without spots or bands ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ) or mostly hyaline, with distal tips of rays dark ( Figs. 1–2 View FIGURE 1 View FIGURE 2 ). Anal fin with irregular dark gray or black blotch or band on basal portion of fin ( Fig. 1 View FIGURE 1 ), or blotch absent ( Fig. 2 View FIGURE 2 ; see below for variation in coloration among populations). Caudal fin with dark pigment covering post-ural plates and distal tips of fin, interrupted by pale vertical band ( Fig. 1 View FIGURE 1 ).

Sexual dimorphism. Male specimens exhibited thickened pectoral spines ( Fig. 7 View FIGURE 7 ); however, contrary to what is reported in other Loricaria species, modifications to lip and barbel morphology (Isbrücker, 1981) were not observed in specimens examined.

Geographical distribution and habitat. Loricaria nimairaco is known from the Orteguaza River, the main tributary of the Caquetá River basin, an Andean River draining into the upper portion of the Amazon River, the Putumayo River, and from the Amazon River at Leticia, Colombia ( Fig. 8 View FIGURE 8 ). According to field notes from ROM archives (obtained thanks to N. K. Lujan), one of the specimens (ROM 107225) was captured in high current, over predominantly mud substrate with organic matter. In contrast, a small specimen (ROM 107265) was collected in a presumably lower gradient stream in slow current, where the bottom was predominantly cobble mixed with sand, with organic matter.

Etymology. The specific name nimairaco [nɨmáìraco] in the Uitoto-Muinane language from Peru, means “ house of a wise man ” ( Minor, Hendrich-Minor, 2008:86). In tribute to our friend and colleague, José Iván Mojica, late professor of the Instituto de Ciencias Naturales de la Universidad Nacional de Colombia. His contributions to Colombian ichthyology (biology, ecology, systematics, and biogeography of freshwater fishes) have made it possible to advance in the conservation of the country’s fishes and rivers, such as the Amazon, the river that was always the home of the wise. A noun in apposition.

Conservation status. Loricaria nimairaco is found in drainages of the Andean piedmont of the Amazon and upper Amazon ( Fig. 8 View FIGURE 8 ) at nine localities in three basins of Colombia, in the Orteguaza (3), Putumayo (1), and Amazon River (5). Aspects such as increasing rate of deforestation of the watersheds, gold mining activities, cattle ranching, and oil exploitation projects occur in the region where the species is recorded (Ayram et al., 2020; Clerici et al., 2020) representing a threat to the species; thus, monitoring of the populations should be implemented. Such monitoring programs and decision-making by environmental authorities (i.e., Corporaciones Autónomas Regionales-CAR) are currently advancing in the ordering and management of the country’s hydrographic basins, established by decree 1729 of 2002. The geographic distribution (83,689.5 km 2) represented as EOO (EOO = B1) categorizes the species as Least Concern (LC) according to the IUCN Subcommittee on Standards and Applications (IUCN 2022).

Color variation within Loricaria nimairaco from the Putumayo River. Specimens were collected in the Piedmont and lowland ecoregions of the Putumayo River basin from main river channels, floodplain forest, and Terra-firme streams ( Figs. 9A–C View FIGURE 9 ). Specimens captured at those localities showed some differences from populations present at the Orteguaza River, and along the upper Amazon River ( Colombia). The main difference was the coloration of the dorsal portion of the head ( Fig. 2 View FIGURE 2 ) from specimens from the Orteguaza and Amazon River (at Leticia); individuals from the Putumayo River have two dark longitudinal stripes from the tip of the snout to the predorsal plates ( Fig. 2 View FIGURE 2 ).

Furthermore, the anal fin lacked dark pigmentation ( Fig. 2 View FIGURE 2 ) in contrast to populations of the Orteguaza River and around Leticia, which exhibits a dark spot near the base of the anal fin ( Fig. 1 View FIGURE 1 ). Meristic counts and measurements show some overlap with those of Loricaria simillima Regan, 1904 and totally overlap with what was identified as the new species here (Tab. 2); however, the new species and L. simillima can be differentiated by external morphology (see Diagnosis), meristic counts (Tab. 2), and molecular evidence (see Tab. 3; S 1, S2, S3). At present, molecular data are unavailable to assess the identity of populations in the Putumayo River, and further efforts should be made to include samples from that locality in future molecular analyses of the species.

Genetic differentiation and species delimitation. Genetic distances ( Tab. 3) were calculated between Loricaria nimairaco and morphologically similar, and geographically closely related species, which were used for the ABGD analysis (see below). Loricaria nimairaco is most closely related to Loricaria cf. simillima from the upper Amazon River in Peru ( Fig. 10 View FIGURE 10 ) and form a cluster as the next divergent branch to the remaining

Loricaria species included here (Genbank records from Pereira et al., 2013; Tab. 4).

Rhadinoloricaria is divergent from Loricaria , followed by Spatuloricaria caquetae (Fowler,

1943) as the next divergent node to that cluster, and Rineloricaria cf. lanceolata (Günther,

1868) as divergent from ( Spatuloricaria ( Rhadinoloricaria + Loricaria )) ( Fig. 10 View FIGURE 10 ).

Sequences identified as Loricaria aff. nickeriensis were obtained from Genbank ( Tab. 4) from Papa et al. (2021), including fishes from the Maroni River (close to the type locality of the species, see Discussion below). It was found that between L. nimairaco (n = 2) and L. cf. nickeriensis (n = 6; not the one referred to by Galvis et al., 2006) the distances are between 5.7–6.1% of genetic divergence, showing a clear differentiation between both species. This also further supports that what was identified by Galvis et al. (2006) as L. nickeriensis , does not belong to the latter, and is maintained here as Loricaria sp. until further data are available; thus, L. nickeriensis is not present in Colombia.

The new species is morphologically more similar to L. simillima , a species considered widespread in the Amazon River basin (upper, middle, and lower portions), La Plata and Orinoco River basin. We compared the new species to four samples identified as L. simillima . As shown in Fig. 10 View FIGURE 10 , Loricaria cf. simillima_ MK 861710.1 is the most next divergent node to the L. nimairaco lineage, indicating close relationship, or belonging to the same species. However, we maintained the former as L. cf. simillima for two main reasons. First, we did not examine vouchers of the samples included in Genbank (MK861710.1) from a study of fishes in the Peruvian Amazon (according to Genbank records, Tab. 4, from an unpublished study). Secondly, the samples of the new species and L. cf. simillima are 2.7–3.0% divergent ( Tab. 3), indicating species-level differentiation (see below for a discussion). A sample from the Pastaza River, upper Amazon, Ecuador, close to the type locality of L. simillima (Canelos, Ecuador), was included for comparison ( Tab. 4; see below for a discussion). From that sample the new species showed a divergence of 6.0–7.0%, indicating species-level differentiation (Orteguaza River vs. Pastaza River). Two additional samples from the Amazon River basin, Brazil (MCP 46182 and MCP 46205) were 4.8–5.1% divergent from the new species (see below for a discussion). These results indicate taxonomic differentiation between what is considered L. simillima (in this case from the Amazon River in Brazil, Ecuador, and Peru) and the new species from the Andean localities in the upper Amazon River basin in Colombia.

Further comparisons were made with samples identified as Loricaria cataphracta , L. cf. cataphracta , and an unidentified species of Loricaria from the Paraguay River ( Loricaria sp. Paraguay). We analyzed four samples identified as L. cataphracta from Genbank ( Tab. 4), all from the Maroni River ( Papa et al., 2021). The new species was 6.0% divergent from L. cataphracta , the type species of the genus. It is worth noting that the samples from the Maroni River are close to the type locality of L. cataphracta in the coastal rivers of Suriname. Loricaria sp. Paraguay ( Paraguay River basin; MCP 36566) is related to the cluster formed by samples of the former ( Fig. 10 View FIGURE 10 ) indicating a relationship between both populations; that result was also obtained by Covain et al. (2016: fig. 7) from samples from the same basin. The new species is 5.8% divergent from the unidentified Loricaria , indicating taxonomic differentiation. Five samples identified as L. cf. cataphracta ( Tab. 4; unpublished study) from the lower Amazon River basin, near Santarém, Pará State, were 6.5–7.6% divergent from the new species.

bPTP analysis supported Loricaria nimairaco as a different lineage (species) from the remaining Loricaria included here ( Fig. 10 View FIGURE 10 and S 1 View FIGURE 1 ), including divergence from Loricaria cf. simillima MK 861710.1, which is more related to the former. The same result was obtained through GMYC (S2) and ABGC (S3) ( Fig. 10 View FIGURE 10 ). Through species delimitation analyses included here, there were only three differences: bPTP found L. simillima OP 407984 and OP407985 as different species ( Fig. 10 View FIGURE 10 ; S 1 View FIGURE 1 ), while GMYC and ABGC found them as a single lineage ( Tab. 3; S2); on the other hand, through bPTP and GMYC, Rhadinoloricaria condei OP 407988 and Rhadinoloricaria cf. condei OP 407987 were found as separate species ( Fig. 10 View FIGURE 10 ; S 1–S View FIGURE 1 2 View FIGURE 2 ); ABGD found Loricaria sp. Paraguay as a separate lineage from L. cataphracta (S3). Thus, the main target of the present study, L. nimairaco , was invariably found as a different species further supporting the presence of a new species at the upper Amazon River in Colombia.