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A recent expedition to lower Yaguaron river basin in northeastern Uruguay, revealed the presence of the loricariid catfish ‘Hemiancistrus’ punctulatus Cardozo & Malabarba, 1999, which represents the first record of this species for the country. We propose it as an endangered species for Uruguay considering its restricted distribution.

Hypostominae is the largest subfamily of Loricariidae, and is widely distributed throughout the Neotropic. In the present article, we analyze three Loricariidae species that were considered part of Hypostominae, from three different tribes, to discuss chromosome evolution in this fish group and to review the existent data for the subfamily. Rhinelepis aspera had 54 chromosomes (20m + 26sm+8st), whereas Pterygoplichthys ambrosettii and Megalancistrus parananus had 52 chromosomes, with 16m+24sm+8st+4a and 18m+24sm+10st, respectively. The karyological data were compared with existent phylogenetic hypotheses, indicating a common ancestor with 2n = 52 chromosomes for the Acanthicus, Hemiancistrus, and Peckoltia clades, as well as for Hypostomini. Shared recurrent characteristics of the tribes are discussed, as well as peculiarities of genera Ancistrus and Hypostomus. We propose that the occurrence of fragile sites demonstrated for Ancistrus facilitated chromosomal rearrangements that decreased the proportion of metacentric/submetacentric chromosomes and the diploid number in many species from this genus. Although Hypostominae is usually considered a subfamily with derived chromosome features, our revision shows that this is valid only for Hypostomini and Ancistrini, which have a divergent chromosome evolution from other tribes that seems to conserve plesiomorphic features.

The Neotropical catfish family Loricariidae is the fifth most species-rich vertebrate family on Earth, with over 800 valid species. The Hypostominae is its most species-rich, geographically widespread, and ecomorphologically diverse subfamily. Here, we provide a comprehensive molecular phylogenetic reappraisal of genus-level relationships in the Hypostominae based on our sequencing and analysis of two mitochondrial and three nuclear loci (4293bp total). Our most striking large-scale systematic discovery was that the tribe Hypostomini, which has traditionally been recognized as sister to tribe Ancistrini based on morphological data, was nested within Ancistrini. This required recognition of seven additional tribe-level clades: the Chaetostoma Clade, the Pseudancistrus Clade, the Lithoxus Clade, the 'Pseudancistrus' Clade, the Acanthicus Clade, the Hemiancistrus Clade, and the Peckoltia Clade. Results of our analysis, which included type- and non-type species for every valid genus in Hypostominae, support the reevaluation and restriction of several historically problematic genera, including Baryancistrus, Cordylancistrus, Hemiancistrus, and Peckoltia. Much of the deep lineage diversity in Hypostominae is restricted to Guiana Shield and northern Andean drainages, with three tribe-level clades still largely restricted to the Guiana Shield. Of the six geographically widespread clades, a paraphyletic assemblage of three contain lineages restricted to drainages west of the Andes Mountains, suggesting that early diversification of the Hypostominae predated the late Miocene surge in Andean uplift. Our results also highlight examples of trophic ecological diversification and convergence in the Loricariidae, including support for three independent origins of highly similar and globally unique morphological specializations for eating wood.

Hemiancistrus landoni Eigenmann 1916 Figure 4 Hemiancistrus landoni Eigenmann 1916:84. Type locality: Naranjito, Ecuador. Hemiancistrus hammarlundi Rendahl 1937:2, Fig. 1. Type locality: Río Clementina system, northwest of Babahoyo, Los Ríos, Ecuador. Material examined. All from Ecuador, El Oro Province, MEPN-5948, 1 ex., 171.5 mm SL, La Cuca, canal de riego, río Arenillas, Granja PREDESUR, approx. 03°30'00"S 80°04'20"W, R. Barriga et al., 13 April 1979. MEPN- 5954, 1 ex., 88.6 mm SL, Río Piedras, curso superior del río Arenillas, approx. 03°38'10"S 79°55'40"W, R. Barriga et al., 12 April 1979. MEPN-17505, 1ex. 68.7 mm SL, Río Zaracay, approx. 03°38'55"S 79°52'180" W, P. Tufiño & R. Barriga, 20 November 2010. Guayas Province, MEPN-9820, 1 ex., 59.9 mm SL, Río Minas, donde cruza la cooperativa 23 de Noviembre, 9 km S de Naranjal, approx., 02°41'26"S 79°38'16"W, R. Barriga, 22 September 1992. MEPN-15118, 1 ex., 134.9 mm SL, Río Minas, donde cruza la cooperativa 23 de Noviembre, 9 km S de Naranjal, approx., 02°41'26"S 79°38'16"W, R. Barriga, 22 September 1992. Los Ríos Province, MEPN-9926, 8 ex. (7 Alc. 1 Dry skeleton), 128.4–205.8 mm SL, Río Catarama, cerca de la poblacion Corona, approx. 01°37'23"S 79°28'20"W, R. Barriga, 15 February 1997. MEPN-10389, 1 ex., 214.6 mm SL, Río Quevedo, approx. 01°02'04"S 79°27'43"W, C. Estrella, May 1953. MEPN-17049, 1 ex., 60.6 mm SL, Río Jujan, cerca de la población de Jujan, approx. 01°53'04S 79°33'06"W, S. Abril, 23 June 1986. MEPN-17050, 1 ex., 84.8 mm SL, Quevedo, G. Onore, November 1983. MEPN-18151, 3 ex., 192.3–213.4 mm SL, Río Las Juntas, afluente del río Babahoyo, approx. 01°52'06"S 79°22'43"W, M. Olalla, 12 March 1964. Manabí Province, MEPN-9099, 1 ex., 135.6 mm SL, Río Portoviejo, Laguna de Poza Honda, parte inferior, approx., 01°04'55"S 80°09'16"W, R. Barriga, 0 5 February 1993. MEPN-17952, 6 ex., 56.3–183.9 mm SL, Río Portoviejo, 1 km aguas abajo de la primera compuerta, approx., 01°06'21"S 80°09'41"W, R. Barriga et al., 0 3 October 1992. Hemiancistrus landoni is recognized among all species of Hemiancistrus sensu lato, except for H. medians by its abdomen, which is completely covered by small bony plates, and has a peculiar color pattern, rounded dark spots (vs. abdomen naked with light spots or plain). According to the figures and redescription indicated by Fisch- Muller et al. (2012), H. landoni can be recognized from H. medians, by its dorsal fin when folded does not reach the origin of the adipose fin versus the dorsal fin folded reaches the origin of the adipose fin. Further recognized by its head shape, which is less deep, and by its supraoccipital without a keel. In H. medians, the head is massive, and the supraoccipital has a keel. The eye is smaller in H. landoni than in H. medians, 15%–16% HL versus 18%–27% HL, respectively. Finally, the number of cheek odontodes is smaller in H. landoni than in H. medians, 10–20 vs. 20–60. Some large specimens show highly developed, long and pointed odontodes, on distal and dorsal portion of pectoral spines. This condition, as in other cases, may occur in sexually active adult males. Hemiancistrus landoni is an endemic species of the Pacific slope of Ecuador, and is found exclusively in aquatic systems of the Guayas River Basin and other water courses related to this basin. Comparative osteology. On the three species identified, we examined the bones that are related to the mobility of the opercular bone. The bones are the sphenotic, the compound pterotic (from now the pterotic), the hyomandibular and the opercular. The observed changes in the state or condition of each bone are related to the development of the musculature involved in the movement of the opercular and concomitant of the developed odontodes associated. The observed changes on the sphenotic occur on the posterior surface. Two conditions are perceived; in the first condition, the posterior region has an excavation or canal, extending from the middle of the bone to the ventral region of the bone; the area from the middle of the bone towards the dorsal region is massive (Fig. 6 A). The second condition is an excavation or canal that runs along the entire posterior surface, from the dorsal to the ventral. This channel is open in the ventral region, but towards the dorsal border it may be totally or partially open (Fig. 6 B). In H. annectens the first condition is observed, while in H. landoni and in H. furtivus, the second condition is observed, the canal is almost occluded at the dorsal border. The pterotic bone has on its anterior surface something similar to that indicated for the sphenotic. In the first condition we can observe the presence of a canal that is occluded or closed towards the dorsal region of the bone (Fig. 7 A). In the second condition the canal runs all or nearly all of the entire anterior surface of the pterotic bone (Fig. 7 B). By articulating the sphenotic and pterotic bones, the canal partially becomes a tunnel. The tunnel may be closed or open dorsally. In H. annectens, the first condition is observed, the pterotic canal is occluded or the tunnel is closed. In H. landoni and in H. furtivus, the second condition is observed, here the channel and tunnel runs almost all the anterior surface of the pterotic and the posterior surface of the sphenotic. In this case the tunnel closes towards the dorsal region. On the ventral and anterior border of the pterotic there is a fossa and a process (anterior process of the pteroticsupracleitrum according to Armbruster 2004). Again, two conditions related to this region are observed. In the first condition, the fossa and the process are slightly developed (Fig. 7 A). In the second, there is an appreciable development of the fossa and the process (Fig. 7 B). In H. annectens, the first condition is observed, while in H. landoni and in H. furtivus, the second condition is observed. On the analyzed species, the opercular bone presents two different forms (Fig. 8). In the first condition, the general shape or contour of the bone is almost triangular, similar to that described by Schaefer (1987) for Hypostomus plecostomus and Cochlidon cochliodon and Armbruster (2004) for Hemiancistrus maracaiboensis and Hypostomus taphorni (condition 0). In the second condition, the opercular has the contour of the opercular in the form of a paddle with a posterior dorsal projection, similar to that described by Schaefer (1987) for Peckoltia niveata and by Armbruster (2004) for Peckoltia sp. (Condition 1, Type- Peckoltia). The first condition of the opercular is present in H. annectens (Fig. 8 A), while the second condition is observed in H. landoni and H. furtivus (Fig. 8 B). The changes in opercular shape can be related to the increase in its rotational capacity at the point of support (condyle of articulation with the hyomandibular) and its properties as a lever. The conditions or states observed could be used to include the species under study into the Hypostomini or Ancistrini sensu Armbruster (2004). The changes noted in the three bones are linked to increased development (increased diameter or muscle thickness) and increased surfaces of origin and insertion of the levator operculi and dilator operculi muscles, which was evidenced during the preparation of skeletons. Discussion. The status of the genus Hemiancistrus is still controversial. The loss of the holotype of H. medians, and the way Kner (1854) presented the original description, generated doubts and discrepancies about the correct identity of this species. Fisch-Muller et al. (2012) established the taxonomic status and the identity of the type species, in spite of the descriptions provided by Günther (1864) and Regan (1904). We do not have specimens of H. medians, however, as indicated by Fisch-Muller et al. (2012) and Armbruster et al. (2015), H. medians and H. landoni share some external morphological characteristics not observed in the other species included in Hemiancistrus sensu lato, such as the presence of keels in the lateral plates of the body and a similar coloration pattern. The way the abdomen is covered appears to have some difference between H. medians and H. landoni, but none of the other species included in the group has such an extended abdominal covering. According with Armbruster et al. (2015) only H. medians is included in the genus Hemiancistrus. Therefore, the generic status of H. landoni and the other species remains uncertain. Hemiancistrus furtivus is represented at the MEPN by seven specimens in five cataloged lots. Only four are in good conditions, and/or with an appreciable standard length. Comparisons with original descriptions of the geographically nearest species were made carefully, and the external characters observed on H. furtivus shows that it is a new species. The belly is totally naked, the dorsal and caudal fins have a distinctive color pattern, and the small movable cheek odontodes differ from that of other Pacific Coast species described or placed in Hemiancistrus. In spite of this, the body color pattern observed on our specimens is very close with that reported by Eigenmann (1916) in the original description of H. landoni. He pointed out that the body has four oblique transverse saddles, the first behind the eyes, the second at the end of the dorsal fin, the third at the level of adipose fin, and the fourth at the caudal-fin origin. On our specimens of H. landoni, the presence of saddles is variable in that some are very evident while in others they are very faint or no traces are observed (Fig. 2). Two more species, were originally described from the Pacific versant of Ecuador, H. hammarlundi Rendahl 1937, and H. fugleri Ovchynnyk 1971. We agree with they are synonymous with H. landoni and H. annectens, respectively. The original description of H. hammarlundi was made on a unique specimen of 70.4 mm SL (Armbruster per. comm.). This specimen has small patches of granular plates on belly, and 20 movable odontodes developed in the cheek area. This is clearly different to that observed in H. furtivus. On the other hand, Ovchynnyk (1971) in the original description of H. fugleri, points out that the folded dorsal fin reaches or is very close to adipose-fin origin, and that the belly has small patches of granular plates. The specimen used was 91 mm SL. Only the examined juveniles of H. annectens show that the folded dorsal fin reaches the adipose-fin origin, and they also have small patches of granular plates on belly. The first character is useful to distinguish juveniles from H. landoni and H. furtivus, but the character changes with size; in large specimens of the three species, the folded dorsal fin does not reach the adipose-fin origin. Also, the figures provided by Ovchynnyk (1971) show a color pattern of the body and fins similar to H. annectens, and different to that observed in H. furtivus. Additionally, there are no developed cheek odontodes in H. fugleri. These results support the synonymy proposed by Armbruster et al. (2015) between the species previously described from Ecuador, and confirms the presence of the new species. The completely naked abdomen, the dark rounded dots on it, and the small movable cheek odontodes distinguish H. furtivus from all other species included in Hemiancistrus sensu lato (Armbruster et al. 2015). Finally, Armbruster et al. (2015) established at least three groups within Hemiancistrus sensu lato. The groupings are based on morphological similarity of species. The species H. landoni and H. furtivus are similar in overall body shape and the color pattern, but the cover of the abdomen and the degree development of mobile cheek odontodes are different. Despite these facts both species are included in the H. landoni group. Hemiancistrus annectens, H. aspidolepis, H. maracaiboensis, H. holostictus and H. wilsoni, inhabit the trans- Andean region, Panamá, Maracaibo lake basin, the rivers Magdalena, Cauca, Atrato, San Juan (Colombia), and Santiago (Ecuador). When comparing the original descriptions of all species, and specimens of H. annectens, it is evident that the external morphology, the meristic and morphometric data, and the color pattern are similar. This fact was previously detected by Schultz (1944), and mentioned by Regan (1913) and Eigenmann (1918). Some morphometric differences can be related with the size, the fixation and preservations conditions of the type specimens. At this moment, we do not have specimens of the other species on hand, and we are unable to offer diagnostics characters to recognize each species. A study to establish the status of each species is necessary, using direct comparison of fresh and well preserved specimens from each basin. In the meantime, the use of the names proposed to each basin is suggested. Recently, Armbruster et al. (2015) reassign to the genus Hypostomus the five species, as a consequence of the results obtained on phylogenetic analyses. The external morphology of the five trans-Andean species of Hypostomus seems to indicate that they do not belong in the genus Hemiancistrus or even to the Ancistrini group, as pointed in morphological and molecular phylogenies (Armbruster 2004, 2008; Lujan et al 2015). The comparative analysis of the bones related to the movement of the opercular, support the placement of H. annectens in the Hypostomini and H. landoni and H. furtivus in the Ancistrini. In order to establish the proper generic allocation of H. annectens a project is being carried out which includes a comparative analysis of the indicated bones, between this species and species traditionally included in the genus Hypostomus. In an analogous way, it is hoped to be able to compare osteologically the species included in the genus Hemiancistrus sensu lato to indicate its appropriate taxonomic status., Published as part of Provenzano, Francisco & Barriga, Ramiro, 2017, The species of Hemiancistrus (Siluriformes: Loricariidae) from Ecuador, pp. 221-235 in Zootaxa 4272 (2) on pages 229-234, DOI: 10.11646/zootaxa.4272.2.4, http://zenodo.org/record/583853, {"references":["Eigenmann, C. H. (1916) New and rare fishes from South American rivers. Annals of the Carnegie Museum, 10 (1 - 2), 77 - 86, pls. 13 - 16.","Rendahl, H. (1937) Einige Fische aus Ecuador und Bolivia. Arkiv for Zoologi, 29 (3), A (11), 1 - 11.","Armbruster, J. W. (2004) Phylogenetic relationships of the suckermouth armored catfishes (Loricariidae) with emphasis on the Hypostominae and Ancistrinae. Zoological Journal of the Linnaean Society, 141 (1), 1 - 80.","Schaefer, S. A. (1987) Osteology of Hypostomus plecostomus (Linnaeus), with a phylogenetic analysis of the loricariid subfamilies (Pisces: Siluroidei). Contributions in Science, Natural History Museum of Los Angeles County, 394, 1 - 31.","Kner, R. (1854) Die Hypostomiden. Zweite Hauptgruppe der Familie der Panzerfische. (Loricata vel Goniodontes). Denkschriften der Mathematisch- Naturwissenschaftlichen Classe der Kaiserlichen Akademie der Wissenschaften in Wien, 7, 251 - 286, pls. 1 - 5.","Gunther, A. (1864) Catalogue of the Fishes in the British Museum. Fol. 5. Catalogue of the Physostomi, Containing the Families Siluridae, Characinidae, Haplochitonidae, Sternoptychidae, Scopelidae, Stomiatidae in the Collection of the British Museum. Trustees, London, xxii + 455 pp.","Regan, C. T. (1904) A monograph of the fishes of the family Loricariidae. Transactions of the Zoological Society of London, 17 (3), 191 - 350, pls. 9 - 21.","Ovchynnyk, M. M. (1971) Unrecorded and new species of fishes from fresh waters of Ecuador. Zoologischer Anzeiger, 187 (1 - 2), 82 - 122.","Schultz, L. P. (1944) The catfishes of Venezuela, with descriptions of thirty-eight new forms. Proceedings of the United States National Museum, 94 (3172), 173 - 338, pls. 1 - 14.","Regan, C. T. (1913) The fishes of the San Juan River, Colombia. Annals and Magazine of Natural History, Series 8, 12 (71), 462 - 473.","Eigenmann, C. H. (1918) Eighteen new species of fishes from northwestern South America. Proceedings of the American Philosophical Society, 56 (7), 673 - 689.","Lujan, N. K., Armbruster, J. W., Lovejoy, N. & Lopez-Fernandez, H. (2015) Multilocus molecular phylogeny of the suckermouth armored catfishes (Siluriformes: Loricariidae) with a focus on subfamily Hypostominae. Molecular Phylogenetics and Evolution, 62, 269 - 288."]}

Key to the species commonly referred to as Hemiancistrus in Ecuador 1a Cheek region with four to eight, small, scarcely developed odontodes, visible mostly on adult specimens. These odontodes are associated with a bony plate, with reduced mobility or immobile. Dorsal fin folded reaches the origin of adipose fin in juveniles, or very close in adults. Caudal fin furcate. Santiago River Basin, province of Esmeraldas, NW of Ecuador............................................................................................. Hypostomus annectens 1b Cheek region with 12 or more developed odontodes, very small in juveniles. These odontodes are associated with connective tissue, they are located behind a bony plate or bony granulations, and are always mobile. Dorsal fin folded does not reach adipose-fin origin. Caudal fin emarginate..................................................................... 2 2a Ventral surface of the head and abdomen covered with small plates or granulations in specimens with 80 mm SL or more. Cheek odontodes 15 or more, well developed, longest (most posterior) greater than eye diameter. Dorsal fin with rounded dark dots arranged in vertical lines just in the middle of interradial membrane. Guayas, Arenillas, Puyango and Zaracay Rivers systems, provinces of Manabí, Los Rios, Guayas and El Oro..................................... Hemiancistrus landoni 2b Ventral surface of the head and abdomen completely naked in specimens 85 mm SL. Cheek odontodes 12–15, very few developed, longest less than eye diameter. Dorsal fin with irregular dark dots arranged in vertical lines on the interradial membrane close to the rays. Esmeraldas river system, provinces of Pichincha and Esmeraldas................. Hemiancistrus furtivus

Hemiancistrus furtivus new species Tables 1 & 2, Figures 1 & 2 Holotype. MEPN 11569, 83.0 mm SL, Ecuador, Pichincha Province, Esmeraldas River Basin, Río Silanche, río Blanco tributary, close to San Francisco de Silanche town, approx. 00°08´45´´N 79°16´38´´W, R. Barriga S. and A. Villacis, 0 7 November 2005, RBS05-24. Paratypes. All from Ecuador, Esmeraldas River Basin: MEPN 18411, 1 ex., 99.8 mm SL, Same data as holotype. MEPN 4475, 1 ex., 79.2 mm SL, C&S, Esmeraldas Province, Estero Chipo a 11 km de Quinindé, vía Golondrinas-Buenos Aires, afluente del Río Blanco, approx. 00°16'28"N 79°24'11"W, R. Barriga, and C. Cerón, 13 March 1985, RBS 85-96. MEPN 4488, 1 ex., mm SL, Esmeraldas Province, Estero Mendoza, in front to Estero Cole a 1 km de la población del mismo nombre, approx. 00°27'00" N 79°24'09"W, R. Barriga, C. Cerón, and J. Caicedo, 10 March 1985, RBS 85-91. MEPN 11421, 1 ex., 54.4 mm SL, Esmeraldas Province, Río Quinindé. 00°18'49''N 79°29'01''W, R. Barriga S. and A. Villacis, 0 5 November 2005, RBS 05-29. MEPN 11497, 1 ex., 70.3 mm SL, Esmeraldas Province, Río Chamba, a 5 km de la vía Quinindé-Esmeraldas, approx. 00°15'04''N 79°21'07''W, R. Barriga S. and A. Villacis, 0 1 November 2005, RBS 05-25. MCZ 48772, 13 ex., (12 Alc. 1 C&S), 55–97 mm SL, Esmeraldas Province, Río Tabuche, (Riachuelo) 49 km SE Esmeraldas, approx. 00°43'07''N 79°32'57''W, T. Roberts, C. Gilbert, and M. Silva, 20 October 1971. AUM 4242 (out MCZ 48772), 1 ex., 75.7 mm SL, same data MCZ 48772. MEPN-19058 (out MCZ 48772), 2 ex., (1 Alc. 1 C&S), 88.3–100.5 mm SL, same data MCZ 48772. Diagnosis. Hemiancistrus furtivus is distinguished from its unique geographical congener H. landoni and from H. medians by the totally naked abdomen and the color pattern of the dorsal and caudal fins. The dorsal fin has vertical rows of nearly rounded spots, dark (black or brown), on the interradial membranes, very near or attached to the rays, in H. landon i the dorsal fin has vertical rows of dark dots in the middle of the interradial membrane (Fig. 2), while in H. medians the dorsal fin has vertical rows of dark dots on the interradial membrane near and, over the rays. In H. furtivus, the dots are smaller, near the diameter of eye or less, whereas the dots are greater than eye diameter in H. landoni and H. medians. On the caudal fin, H. furtivus has transverse rows of spots nearly rounded, dark (black) randomly dispersed on the interradial membrane and rays, mostly on the distal area, where they have the appearance of transverse dark bands. In H. landoni, the caudal fin color pattern is similar to the dorsal fin. In H. furtivus there are between 12–15 cheek odontodes, each odontode emerges from a fleshy sheath, only its tip protrudes and is visible, the length of the longest odontode is less than eye diameter. In H. landoni there are more than 15 cheek odontodes, with a similar condition as H. furtivus, but around half of each odontode is visible, the length of longest (most posterior) is greater than the eye diameter. The new species can be recognized from all other species of Hemiancistrus sensu lato (Armbruster et al. 2015) except H. medians and H. landoni by the presence of dark rounded dots on the belly vs. belly whitish or with pale color homogeneous, without dots or spots. Finally, the species grouped in the ‘H.’ chlorostistus group from Brazil have patches of small plates on the abdomen while H. furtivus has the abdomen completely naked. Description. Morphometric data given in Table 1. Body robust, progressively compressed posteriorly. Caudal peduncle compressed, deep and robust. Dorsal profile of body from tip of snout through eyes, straight, with a slope close to 45°, from eyes to dorsal-fin origin gently convex, then gradually descending straight to caudal-fin origin. Ventral profile of body flat and straight or slightly concave. Ventral surface of head and belly naked to anus. From the anus to anal-fin origin, a straight naked band is present bordered by end of lateral plates. Urogenital papilla absent, the cloaca is a small but evident fleshy tube. Head wide and little depressed. Snout not projected with naked, oval tip. Eyes in dorsolateral position, orbits raised. Interorbital space broad. Supraoccipital slightly convex, posterior border rounded. Cheek mobile odontodes 12–15, tiny and thin. Each odontode arises from fleshy cylindrical base, and only tip protrudes. Tips orange or amber. Mobile odontodes roughly arranged in rosette pattern. Opercular bone exposed, visible externally, its lateral margin with small odontodes. Mouth oval or rounded. Upper lip narrow, usually covering premaxilla and only external surface is visible, edge is almost horizontal with very minute undulations. Internal surface papillose. Lower lip broad, its border crenulated. Lower lip surface papillose. Papillae smaller near border of lip increasing in size near lower jaws. Papillae of anterior lip similar in size to those near lower jaws. Maxillary barbels short, united to lower lip, leaving only tip free. Premaxilla slightly longer than dentary. Premaxillae nearly straight forming ~180° angle. Dentaries separate, forming open “V” between them, with angle 95°–105° between rami. Teeth numerous and minute, 25–35 teeth in each hemimandible. Premaxillary and dentary teeth of same size. Teeth incisor type, asymmetrically bifid, medial cusp longer and wider than lateral cusp. Medial cusp rounded or straight truncated, lateral cusp pointed. Tooth apex curved toward interior of mouth. Tooth apex yellowish, stalk whitish. Premaxillary and dentary with posterior small papillae. Plates on sides of body with keels. Lateral line plates 27 or 28. Post-anal plates 15 or 16. Inter-dorsal plates seven or eight, just in front of adipose-fin soine one small plate with keel. Dorsal-fin origin anterior to vertical passing through pelvic-fin origin. Dorsal-fin with one spinelet, one spine, and seven branched rays; when depressed tip does not reach adipose-fin origin. Adipose-fin well developed and always present. Spine of adipose fin wide, and straight. Pectoral-fin with one spine, and six branched rays. When depressed, pectoral-fin spine reaches less than one third of pelvic-fin spine length. Spine of pectoral-fin with a fleshy tip, and slightly shorter than first branched ray. Pelvic-fin with one spine and five branched rays; its posterior margin surpassed anal-fin base when depressed. Anal-fin with one flexible spine and four branched rays. Caudal-fin rays i,14,i. Caudal-fin emarginate. Color. Specimens preserved in 70% ethanol show little variation in base color. General color of head and dorsolateral surfaces of body dark brown. Dark (black), rectangular, ovals or rounded spots, of different sizes, and randomly arranged on head and body. Spots became smaller, concentrated, and faint or diffuse on snout. Two or three transverse, dark (black), and irregular saddles, anteriorly oriented, first at end of dorsal-fin base, second at adipose fin origin, and last at caudal-fin origin; saddles more visible in dorsal view. Patch of dark spots at caudalfin origin. Base color of abdomen uniform, creamy or whitish, with irregular, dark (black) spots. Dorsal fin with longitudinal rows of nearly rounded spots, dark (black or brown), on interradial membrane, near or attached to the rays. Caudal fin with transverse rows of spots nearly rounded, dark (black) randomly dispersed on interradial membrane and rays, mostly at distal area, where they appear to combine in transverse dark bands. Rest of fins with brown base color with dark (black) spots on spines, branched rays and interradial membranes (Figs. 1–2). Smallest specimen (54.4 mm SL) with dorsal and caudal fins with longitudinal or transverse, respectively, dark bands. Geographical distribution. The specimens were caught in the Esmeraldas River Basin, Provinces of Esmeraldas and Pichincha (Fig. 5). Etymology. The name of the species is taken from the Latin word furtivus meaning: attempting to pass unnoticed or hidden, and alludes to the fact that the species was not detected before despite being in the Ecuadorian Pacific region, one of the best known ichthyologically. An adjective., Published as part of Provenzano, Francisco & Barriga, Ramiro, 2017, The species of Hemiancistrus (Siluriformes: Loricariidae) from Ecuador, pp. 221-235 in Zootaxa 4272 (2) on pages 223-228, DOI: 10.11646/zootaxa.4272.2.4, http://zenodo.org/record/583853

Hemiancistrus platyrhynchus: ANSP-70512, Holotype, 70.7 mm SL, Colombia, Florencia, Orteguasa River basin, Brother Nic��foro Mar��a, 1931. ANSP-70513, Paratype, 67.75 mm SL, Colombia, Florencia, Orteguasa River basin, Brother Nic��foro Mar��a, 1931. MBUCV-V-18376 (ex. ANSP-84570), 3 ex., 37.4���56.1 mm SL, Colombia, Brother Nic��foro Mar��a, 1931., Published as part of Ardila, Carlos, 2017, A new species of the catfish genus Cordylancistrus (Siluriformes, Loricariidae) from the Sierra Nevada de Santa Marta, Colombia, pp. 256-266 in Zootaxa 4329 (3) on page 265, DOI: 10.11646/zootaxa.4329.3.4, http://zenodo.org/record/1002500

Hemiancistrus daguae : FMNH-56052, Holotype, 60.4 mm SL, Colombia, Caldas. FMNH-56053, 3 Paratypes, 32.3���75.8 mm SL, Colombia, Caldas. FMNH-56054, 2 Paratypes, 33.6���65.9 mm SL, Colombia, Caldas., Published as part of Ardila, Carlos, 2017, A new species of the catfish genus Cordylancistrus (Siluriformes, Loricariidae) from the Sierra Nevada de Santa Marta, Colombia, pp. 256-266 in Zootaxa 4329 (3) on page 265, DOI: 10.11646/zootaxa.4329.3.4, http://zenodo.org/record/1002500

At the Fish Collection of the Instituto de Ciencias Biológicas, Escuela Politécnica Nacional, Quito, three species traditionally grouped in the genus Hemiancistrus were identified: H. annectens (Regan 1904), H. landoni Eigenmann 1916, and a new specie described here. The new species inhabits exclusively in the Esmeraldas River Basin, Pacific slope, northwestern Ecuador. It is easily recognized by the completely naked abdomen, with rounded, dark spots, and a different color pattern on the dorsal and caudal fins. A comparative analysis of bones related to the opercular mobility, shows important differences between H. annectens, H. landoni, and the new species, suggesting that H. annectens does not belong to the genus Hemiancistrus or the Ancistrini group. According to the characteristics observed in these bones, H. annectens shows greater similarity to those reported in species of the Hypostomini group, supporting its inclusion in this group, but placing it in the genus Hypostomus requires further analysis. On the other hand, the conditions observed on the bones of Hemiancistrus landoni and the new species suggest that both are inside of the Ancistrini group. The new species is placed in the genus Hemiancistrus tentatively, pending future analysis.

Background The genetic diversity of Neotropical fish fauna is underrepresented in public databases. This distortion is evident for the order Siluriformes, in which the suborders Siluroidei and Loricarioidei share equivalent proportion of species, although far less is known about the genetics of the latter clade, endemic to the Neotropical Region. Recently, this information gap was evident in a study about the structural diversity of fish mitochondrial genomes, and hampered a precise chronological resolution of Siluriformes. It has also prevented molecular ecology investigations about these catfishes, their interactions with the environment, responses to anthropogenic changes and potential uses. Results Using high-throughput sequencing, we provide the nearly complete mitochondrial genomes for 26 Loricariidae and one Callichthyidae species. Structural features were highly conserved. A notable exception was identified in the monophyletic clade comprising species of the Hemiancistrus, Hypostomini and Peckoltia-clades, a ~60 nucleotide-long deletion encompassing the seven nucleotides at the 3′ end of the Conserved Sequence Block (CSB) D of the control region. The expression of mitochondrial genes followed the usual punctuation pattern. Heteroplasmic sites were identified in most species. The retrieved phylogeny strongly corroborates the currently accepted tree, although bringing to debate the relationship between Schizolecis guntheri and Pareiorhaphis garbei, and highlighting the low genetic variability within the Peckoltia-clade, an eco-morphologically diverse and taxonomically problematic group. Conclusions Herein we have launched the use of high-throughput mitochondrial genomics in the studies of the Loricarioidei species. The new genomic resources reduce the information gap on the molecular diversity of Neotropical fish fauna, impacting the capacity to investigate a variety of aspects of the molecular ecology and evolution of these fishes. Additionally, the species showing the partial CSB-D are candidate models to study the replication and transcription of vertebrate mitochondrial genome. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3709-3) contains supplementary material, which is available to authorized users.

Peckoltia is one of the 26 genera that constitute the Ancistrini. Although Peckoltia has been reviewed recently, its taxonomic status is not fully resolved and not easily distinguished from Hemiancistrus. Neither Peckoltia nor Hemiancistrus have any recognized synapomorphies supporting their monophyly. In this paper we describe a new species of Ancistrini from Rio Xingu drainage, Para State, Brazil, and assign it to Peckoltia based on its deep body, presence of large odontodes on the cheeks, and lack of carenate plates on the body. The new species can be easily distinguished from all its congeners by its dorsal-fin color pattern (presence of dark thin stripes in the interradial membranes parallel to fin rays that fragment into small spots in larger specimens vs. bands, spots, dots, or membranes with a darker coloration in all other species). Peckoltia feldbergae, new species, differs from all its congeners except P. bachi, P. oligospila, and P. sabaji by having dark brown spots on the entire body (vs. pre...

Hemiancistrus cerrado is described from the tributaries of rio Araguaia, rio Tocantins basin. Hemiancistrus cerrado has external similarities with H. megalopteryx and H. punctulatus from coastal streams of southern Brazil, and can be distinguished by having a larger internarial width, 15.9-21.1% of head length (vs. 11.2-14.0% in H. megalopteryx and 11.2-13.9% in H. punctulatus) and, with little overlap, by the larger adipose-fin spine length, 9.4-13.6% of standard length (vs. 7.1-8.7% in H. megalopteryx and 7.4-10.0% in H. punctulatus). Hemiancistrus cerrado further differs from H. megalopteryx by having the pectoral-fin spine reaching maximally to the middle of the pelvic-fin spine when adpressed in adult males (vs. reaching tip). Hemiancistrus cerrado differs from other members of Hemiancistrus by color and numerous morphometric and meristic data. Hemiancistrus cerrado é descrito de tributários da margem esquerda do rio Araguaia, bacia do rio Tocantins. Hemiancistrus cerrado possui similaridades externas com H. megalopteryx e H. punctulatus de drenagens costeiras do sul do Brasil, e pode ser separado das duas espécies pela maior distância entre as narinas, 15.9-21.1% do comprimento da cabeça (vs. 11.2-14.0% em H. megalopteryx e 11.2-13.9% em H. punctulatus), e, com alguma sobreposição, pela maior nadadeira adiposa, 9.4-13.6% do comprimento padrão (vs. 7.1-8.7% em H. megalopteryx e 7.4-10.0% em H. punctulatus); de H. megalopteryx ainda difere por espinho da nadadeira peitoral de machos adultos se estendendo até o meio do espinho da nadadeira pélvica quando adpressa (vs. se estendendo até a ponta do espinho). Hemiancistrus cerrado difere de outros congêneres pela coloração e diversos dados merísticos e morfométricos.

Two new species of Hemiancistrus are described: Hemiancistrus votouro n. sp. and Hemiancistrus meizospilos n. sp. from upper rio Uruguai basin. They differ from their congeners except H. chlorostictus, H. megacephalus, and H. macrops by the presence of light dots on fins and lateral and dorsal portions of head and body. Hemiancistrus votouro and H. meizospilos differ from the species above by meristic and morphometric data and by the color pattern. Duas novas espécies de Hemiancistrus são descritas: Hemiancistrus votouro e Hemiancistrus meizospilos da bacia do rio Uruguai superior. Elas diferem dos seus congêneres, exceto de H. chlorostictus, H. megacephalus e H. macrops, pela presença de pontos claros distribuídos nas nadadeiras e nas porções laterais e dorsal da cabeça e do corpo. Hemiancistrus votouro e H. meizospilos diferem das espécies citadas acima por dados merísticos e morfométricos e pelo padrão de colorido.

Three new species of saddled hypostomine loricariids are described. According to a recent phylogenetic analysis, these species are members of the genus Peckoltia. The species differ from all described Peckoltia except Peckoltia furcata and Peckoltia sabaji by having the dentaries meet at an angle greater than 90°. The species also have similarities to Hemiancistrus, and can be separated from all described species by having dorsal saddles. We discuss the taxonomy of Peckoltia, Hemiancistrus, and allied genera and recognize Ancistomus as valid for Peckoltia feldbergae, Hemiancistrus micrommatos, Ancistrus snethlageae, Hemiancistrus spilomma, and Hemiancistrus spinosissimus. We recommend descriptions of genera for several clades of Hemiancistrus and restriction of Hemiancistrus to the type species of the genus, Hemiancistrus medians. Chaetostomus macrops is transferred to Pseudancistrus and recognized as a junior synonym of Pseudancistrus megacephalus. The Hemiancistrus annectens group of species (Hemiancistrus annectens, Hemiancistrus argus, Hypostomus aspidolepis, Hemiancistrus fugleri, Hemiancistrus holostictus, Hemiancistrus maracaiboensis, Hemiancistrus panamensis, Hemiancistrus wilsoni) are recognized in Hypostomus. Multivariate analysis reveals that the newly described species differ from one another in shape space, but overlap broadly with other Peckoltia (Peckoltia lujani), narrowly with other Peckoltia (Peckoltia greedoi), or broadly with Etsaputu (Peckoltia ephippiata).

Financiadora de Estudos e Projetos Conventional and molecular cytogenetic analysis were performed on 15 species of the subfamily Hypostominae, comprising 12 species of the Hypostomini tribe, genus Hypostomus, and three of the Ancistrini tribe, genera Ancistrus and Hemiancistrus. The chromosome number of 2n=52 was observed for Ancistrus multispinis (14m+14sm+24st-a), A. brevipinnis (14m+14sm+24st-a) and Hemiancistrus punctulatus (14m+26sm+12st-a). The nucleolar organizer regions (Ag-NORs) and 18S rDNA sites are simple and terminal for species, A. brevipinnis, A. multispinis and H. punctulatus. In these species, it can be seen that the NORs are also CMA3+/DAPI-. As for the heterochromatin, H. punctulatus showed a small amount of this chromosome component, while A. multispinis and A. brevipinnis showed a larger amount, with large blocks on the long arm of some st-a pairs. In turn, the different species of Hypostomus showed a variation from 64 to 82 chromosomes, exhibiting differences in the karyotype formula between species. The NORs were multiple for most species analyzed, with different phenotypes observed in the number and position, which was also confirmed by FISH analysis, showing an interindividual and interspecific variability. In all species, the NORs were also CMA3+/DAPI _. The heterochromatin pattern distribution was different in each species, being another important chromosome marker. Cytogenetic, molecular, and morphometry analysis were performed in the species Hypostomus albopunctatus (Piracicaba river, SP) and H. heraldoi (Pirapitinga river, GO), including those morphologically similar samples present in the Mogi Guaçu river (SP). All individuals had 2n=74, whereas H. albopunctatus showed 10m+20sm+44st-a and H. heraldoi 8m+20sm+46st-a. These two karyotype formulae were found in the Mogi Guaçu river population. Distinct Ag-NOR phenotypes were observed among the three populations and confirmed by FISH. Regarding the heterochromatin pattern, H. albopunctatus presented terminal bands and an interstitial block. In H. heraldoi, the heterochromatin was found widely distributed in the terminal and interstitial regions of some st-a chromosomes. In these species, the NORs were also CMA3+/DAPI _. RAPD analysis and sequencing of the cytochrome oxidase subunit I (COI) gene were carried out in these two species, in the Mogi Guaçu population and in three more species, H. regani, H. margaritifer, and H. hermanni, obtaining the same dendrogram pattern. All species could be differentiated by their COI sequences, resulting in a total of 16 haplotypes. These analyses, combined with the morphometric data, showed that H. heraldoi and H. albopunctatus are two valid species and the specimens from the Mogi Guaçu river still retain some characteristics of H. albopunctatus, and were provisionally designated as Hypostomus aff. albopunctatus. Due to the large number of species currently included in the Hypostomus genus, along with both the intra and interspecific variability in morphology and color pattern, there are often problems in the taxonomy of this group, which can be assisted by cytogenetic data. This study provided new chromosomal data for Loricariidae, being a valuable cytotaxonomic tool for the Hypostomini tribe. The joint analysis of different characters, such as cytogenetic, molecular, and morphometric, allowed a more precise characterization of different populations of Hypostomus species, helping to clarify their validity as distinct evolutionary units. Análises citogenéticas convencionais e moleculares foram realizadas em 15 espécies da subfamília Hypostominae, compreendendo 12 espécies da tribo Hypostomini, gênero Hypostomus e três da tribo Ancistrini, gêneros Ancistrus e Hemiancistrus. Foi observado 2n=52 para Ancistrus multispinis (14m+14sm+24st-a), A. brevipinnis (14m+14sm+24st-a) e Hemiancistrus punctulatus (14m+26sm+12st-a). As regiões organizadoras de nucléolos (Ag- RONs) e sítios de DNAr 18S são simples e terminais para as espécies A. brevipinnis, A. multispinis e H. punctulatus. Nestas epécies pode-se constatar que as RONs são também CMA3 +/DAPI-. Quanto à heterocromatina, H. punctulatus apresentou pouca quantidade desse componente cromossômico, enquanto que A. multispinis e A. brevipinnis evidenciaram uma maior quantidade, com grandes blocos no braço longo de alguns pares st-a. Por sua vez, as diferentes espécies de Hypostomus mostraram uma variação de 64 a 82 cromossomos, com diferença na fórmula cariotípica entre as espécies. As RONs foram múltiplas para a maioria das espécies analisadas, sendo observados diferentes fenótipos quanto ao número e posição, o que foi também confirmado pela análise de FISH, evidenciando uma variabilidade interindividual e interespecífica. Em todas as espécies as RONs mostraram-se também CMA3 +/DAPI _. O padrão de distribuição da heterocromatina foi diferente em cada espécie, sendo outro importante marcador cromossômico. Análises citogenéticas, moleculares e de morfometria foram realizadas nas espécies Hypostomus albopunctatus (rio Piracicaba, SP) e H. heraldoi (rio Pirapitinga, GO), assim como em exemplares morfologicamente semelhantes presentes no rio Mogi Guaçu (SP). Todos os indivíduos apresentaram 2n=74, sendo que, H. albopunctatus apresentou 10m+20sm+44st-a e H. heraldoi 8m+20sm+46st-a. As duas fórmulas cariotípicas foram encontradas na população do rio Mogi Guaçu. Fenótipos distintos de Ag-RONs foram observados entre as três populações, confirmadas pela FISH. Quanto ao padrão heterocromático, H. albopunctatus apresentou bandas terminais e um bloco intersticial. Em H. heraldoi, a heterocromatina encontrou-se mais amplamente distribuída, nas regiões terminais e intersticiais de alguns cromossomos st-a. Nessas espécies as RONs mostraram-se também CMA3 +/DAPI _. Análises de RAPD e sequenciamento do gene de Citocromo Oxidase subunidade I (COI) foram realizadas nessas duas espécies, na população do rio Mogi Guacu e em mais três espécies, H. regani, H. margaritifer e H. hermanni, obtendo-se o mesmo padrão de dendrograma. Todas as espécies puderam ser diferenciadas por suas sequências COI, resultando num total de 16 haplótipos. Estas análises, aliadas aos dados de morfometria, evidenciaram que H. heraldoi e H. albopunctatus são duas espécies válidas e que os exemplares do rio Mogi Guaçu ainda conservam algumas características de H. albopunctatus, sendo provisoriamente denominados como Hypostomus aff. albopunctatus. Devido ao elevado número de espécies atualmente incluídas no gênero Hypostomus, juntamente com a variabilidade na morfologia e padrão de coloração tanto intra quanto interespecífica, muitas vezes ocorrem problemas na taxonomia desse grupo, a qual pode ser auxiliada pelos dados citogenéticos. Este estudo forneceu novos dados cromossômicos para os Loricariidae, mostrando-se uma boa ferramenta citotaxonômica para a tribo Hypostomini. A análise conjunta de diferentes caracteres, como citogenéticos, moleculares e morfométricos, possibilitou uma caracterização mais precisa de diferentes populações de espécies de Hypostomus, contribuindo para esclarecer sua validade como unidades evolutivas distintas.

Peckoltia contains 12 described species, eight of which are considered valid. Peckoltia arenaria, P. filicaudata, and P. ucayalensis are recognized as synonyms of P. bachi and P. kuhlmanni is recognized as a synonym of P. vittata. In addition, two new species are described. The type species of Peckoltichthys and Sophiancistrus are synonyms of P. bachi and both genera are recognized as junior synonyms of Peckoltia. The species of Peckoltia range throughout much of the Amazon basin, the upper Orinoco, the upper Essequibo, and perhaps the Maroni, and can be identified from most other ancistrins by having dentaries that form angle of 90° or less and from others with angled dentaries by lacking the synapomorphies of those genera. The species of Peckoltia vary from one another mostly in coloration. Peckoltia braueri, P. caenosa n. sp., P. cavatica and P. vittata lack spots on the head while the other species have them. Peckoltia braueri and P. cavatica have orange bands in the dorsal and caudal fins and have the bones and plates of the head and nape outlined in black (vs. no orange bands and head plates and bones not outlined in black in P. caenosa and P. vittata). Peckoltia caenosa has a color pattern consisting of dark vermiculations on the head and abdomen (vs. saddles or blotches on the head and faint dark spots on the abdomen in P. vittata). Among the species with spots on the head, P. lineola n. sp. and P. vermiculata have some of the spots combining to form vermiculations (vs. spots free in P. bachi, P. brevis, P. furcata, and P. oligospila) with the vermiculations larger than the pupil in P. lineola and narrower in P. vermiculata and the vermiculations radiating from a central point in P. vermiculata vs. no such pattern in P. lineola. Peckoltia bachi can be identified from the other species by having widened pelvic-fin spines that can be pulled ventrally such that they are completely ventral and parallel to the body (vs. pelvic-fin spines narrow and cannot be adducted ventral to body) and by having the eye low on the head (vs. high). Peckoltia brevis can be identified from P. furcata and P. oligospila by having well-developed dorsal saddles (vs. saddles faint), no spots on the body behind the nape (vs. spots generally present behind the nape); from P. oligospila by having bands in the caudal fin (vs. spots); and from P. furcata by having the lower caudal-fin spine longer than the upper (vs. upper spine longer). Peckoltia furcata can be identified from P. oligospila by having the upper caudal-fin spine longer than the lower (vs. lower spine longer) and by having bands in the caudal fin (vs. spots). Ancistrus yaravi had been recognized as a species of Peckoltia. The type of A. yaravi is lost, but the original description suggests that the species is the senior synonym of Neblinichthys roraima. A revised morphological phylogeny demonstrates the lack of support for Peckoltia and Hemiancistrus as monophyletic, and phenetic definitions are provided for the two genera. The phylogeny also demonstrates a lack of support of the genus Watawata.

H. megacephalus: MBUCV V 16972, 3 ex., 84.9-107.4 mm SL., Published as part of Francisco Provenzano & Nadia Milani, 2006, Cordylancistrus nephelion (Siluriformes, Loricariidae), a new and endangered species of suckermouth armored catfish from the Tuy River, north-central Venezuela., pp. 29-41 in Zootaxa 1116 on page 39

Hemiancistrus maracaiboensis: MBUCV V 16353, 1 ex., 206.8 mm LS., Published as part of Francisco Provenzano & Nadia Milani, 2006, Cordylancistrus nephelion (Siluriformes, Loricariidae), a new and endangered species of suckermouth armored catfish from the Tuy River, north-central Venezuela., pp. 29-41 in Zootaxa 1116 on page 39

The neotropical freshwater systems have a high number of catfish species (Siluriformes), and many of those are denominated "cascudos" in Brazil. Cytogenetic data about three "cascudos" species fished in the rio Araguaia are described in the present study. The Pterygoplichthys joselimaianus showed 2n=52, with 28 metacentrics (M) chromosomes, 16 submetacentrics (SM) and 8 subtelocentrics/acrocentrics (ST/A) in both sexes. Hemiancistrus spinosissimus showed 2n=52, with karyotype formulae 26M+22SM+4ST, in both sexes. Hemiancistrusspilomma also showed 2n=52, but in this species a ZZ/ZW sex chromosome system (25M+21SM+6ST in females and 24M+22SM+6ST in males) was observed. The cells from H. spinosissimus and P. joselimaianus showed one chromosome pair bearing Ag-NORs, while in the H. spilomma three chromosome pairs bearing Ag-NORs were detected. The data showed in this work reveal particular chromosomal characteristics, important for a good recognition of both Hemincistrus species, and also show the importance of the insertion of cytogenetic data on taxonomic phylogenetic studies. Os sistemas deágua doce neotropicais possuem um alto número de espécies de peixes Siluriformes, muitas das quais popularmente conhecidas como cascudos no Brasil. Dados citogenéticos sobre três espécies de cascudos, capturadas na bacia do rio Araguaia são descritos no presente trabalho. Pterygoplichthys joselimaianus possui 2n=52, com 28 cromossomos metacêntricos (M), 16 submetacêntricos (SM) e 8 subtelecêntricos/acrocêntricos (ST/A) em ambos os sexos. Hemiancistrus spinosissimus revelou 2n=52, com fórmula cariotípica 26M+22SM+4ST, nos dois sexos. H. spilomma também possui 2n=52, porém, nesta espécie foi observado um sistema de cromossomos sexuais do tipo ZZ/ZW (25M+21SM+6ST para fêmeas e 24M+22SM+6ST para machos). As células de H. spinosissimus e P. joselimaianus mostraram um par de cromossomos portadores de Ag-RONs. Em H. spilomma, três pares de cromossomos portadores de Ag-RONs foram observados. Os dados apresentados neste trabalho revelam características cromossômicas particulares, importantes para um bom reconhecimento de ambas as espécies de Hemiancistrus e mostram a importância da inserção dos dados citogenéticos nos estudos taxonômicos e filogenéticos.

Hemiancistrus guahiborum, new species, is described from the Orinoco River drainage of Venezuela. Hemiancistrus guahiborum can be separated from all other Hemiancistrus and all Peckoltia except P. braueri and P. cavatica by having an orange edge to the dorsal and caudal fins. Hemiancistrus guahiborum can be separated from Peckoltia cavatica and P. braueri by having the dorsal fin with separated light spots or uniformly colored (vs. with dark spots forming bands) and the sides either solidly colored or with tan blotches (vs. with dark dorsal saddles). Hemiancistrus guahiborum, espécie nova, é descrita para a bacia do río Orinoco na Venezuela. Se distingue de todas as espécies de Hemiancistrus e Peckoltia, com exceção de Peckoltia cavatica e P. braueri por possuir uma franja alaranjada no bordo das nadadeiras dorsal e caudal. Se distingue de P. cavatica e P. braueri por possuir a nadadeira dorsal com colorido uniforme ou com manchas claras, e por possuir as laterais do corpo de cor uniforme ou com manchas claras.

A phylogenetic analysis of nearly all genera of the Hypostominae and the Ancistrinae is provided based on osteology, external anatomy, and digestive tract anatomy. The results suggest that the Hypostominae is a paraphyletic assemblage. Delturus and Upsilodus form a monophyletic group sister to all other loricariids. Hemipsilichthys, Isbrueckerichthys, Kronichthys, and Pareiorhina form a monophyletic group with Neoplecostomus and the Hypoptopomatinae and are transferred to the Neoplecostominae. The remainder of the Hypostominae is made paraphyletic by the continuing recognition of the Ancistrinae. Ancistrinae is returned to the Hypostominae and recognized as a tribe, Ancistrini. In addition, four new tribes (Corymbophanini, Hypostomini, Pterygoplichthini, and Rhinelepini) are described. Hypostomus is also paraphyletic, the bulk of it forming a monophyletic clade with Aphanotorulus, Cochliodon, and Isorineloricaria. All of the potential monophyletic groups within Hypostomus grade into one another; therefore, Aphanotorulus, Cochliodon, and Isorineloricaria are placed in the synonymy of Hypostomus. Pterygoplichthys and Glyptoperichthys are also polyphyletic, and Liposarcus and Glyptoperichthys are recognized as synonyms of Pterygoplichthys. Sister to Pterygoplichthys is the Hemiancistrus annectens group (including Hypostomus panamensis) which represents an undescribed genus. The phylogeny presented is compared with previous hypotheses. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 141, 1−80.

Hemiancistrus votouro, new species Fig. 1 Holotype. MCP 33594,133.9 mm SL (female); Brazil: Rio Grande do Sul: Benjamin Constant: arroio Lageado Grande (tributary of the rio Passo Fundo, rio Uruguai basin), ca. 2.5 km NE from Votouro Indian Reserve (27°26’50"S 52°37’5"W), W. Bruschi Jr. & J. F. P. da Silva, 1 May 2002. Paratypes. MCP 29661, 99.5-141.2 mm SL (3 males and 2 females); MNRJ 25920, 99.5-136.3 mm SL (1 male and 1 female), collected with the holotype. Diagnosis. Hemiancistrus votouro differs from all other Hemiancistrus except H. chlorostictus, H. meizospilos, H. megacephalus, and H. macrops by the presence of light dots on all fins and the lateral and dorsal portions of body. Hemiancistrus votouro differs from H. chlorostictus by the number of premaxillary teeth (61-79 vs. 30-54), by the larger adipose-fin spine (9.0-10.4% SL vs. 5.8-8.0% SL; Fig. 2), by the deeper caudal peduncle (11.0-11.8% SL vs. 9.6-10.4% SL), by the larger pectoral fin (36.2-41.3% SL vs. 30.6-35.4 % SL), by the larger exposed portion of cleithrum (11.2-12.7% SL vs. 9.3-10.6% SL; Fig. 3), by the narrower body at dorsal-fin origin (17.9-19.8% SL vs. 19.9-25.3% SL) and first anal-fin pterygiophore not exposed (vs. exposed). Hemiancistrus votouro is distinguished from H. meizospilos by the smaller orbit diameter (14.5-16.7% HL vs.16.7-21.0% HL; Fig. 4) and by the much smaller light markings (one to three dots per plate vs. one large dot occupying one to three plates and skin between them). Hemiancistrus votouro differs from H. megacephalus and H. macrops by the number of the light markings per body plate (one to three small dots per plate vs. only one large dot on each body plate). Description. Meristic and proportional measurements in Table 1. Dorsal profile of body gently arched from snout tip to dorsalfin origin. Body narrowing progressively caudally from cleithrum. Trunk mostly straight and tapering slightly to caudal-fin base. Trunk and caudal peduncle mostly rounded in cross section, slightly flattened ventrally, more compressed caudally. Ventral surface flattened. Head slightly concave between orbits; dermal plates not carinate; upper margin of orbits (dorsolateral margin of frontal and sphenotic bones) slightly elevated. Snout broad and rounded anteriorly, slightly concave anterior to nares. Odontodes not forming keels on lateral plates. Dorsal, supramedial, median, and inframedial plate rows complete from head to caudal fin. Abdomen without platelets, except for small patch of platelets between pectoral fins. Cheek plates present on lateral margins of head; snout plates reduced to few granular platelets, absent in rectangular area on snout tip; five rows of plates on caudal peduncle; 25-26 plates in medial plate row. Nuptial males with hypertrophied odontodes slightly larger on tip of pectoralfin spine. Cheek plates evertible with 13-24 hypertrophied odontodes with curved tips, longest odontode one and half times eye diameter (juveniles with fewer and shorter odontodes than adults). Opercle supporting about 15-20 small odontodes in juveniles and adults. Preopercle covered by small platelets. Eyes small (14.5-16.7% HL), iris with large dorsal flap. Lips large, occupying most of ventral surface of head. Lower lip mostly covered with papillae, except for smooth band near its border. Maxillary barbel free and pointed, typically reaching about one third of way from its origin to gill opening. Some individuals with one or both barbels bifurcated. Teeth small, bifid; medial cusp large, blade-like, and slightly rounded; lateral cusp minute, pointed, never reaching more than one third of mesial cusp length. Premaxillary teeth 61 to 79 (mean=71.4). Dentary teeth 61 to 84 (mean=71.8). Upper and lower jaw rami form angles slightly less than 180 o. Dorsal-fin rays II,7; reaching adipose-fin origin when depressed. Dorsal fin originating at vertical line in front of pelvic-fin base; dorsal-fin spinelet V-shaped, locking mechanism functional. Pectoral-fin rays I,6; tip of spine reaching beyond half-length of pelvic-fin origin in both sexes, when depressed. Pelvic-fin rays I,5; tip of spine reaching slightly beyond anal-fin origin when depressed. Anal-fin rays I,4. First anal-fin pterygiophore not exposed. Caudal-fin rays I,14,I; caudal fin slightly truncate. Adipose-fin spine large and thick. Color in alcohol. Dorsal and lateral surface of body and head dark gray, covered with small light dots, less numerous on caudal peduncle; one to three dots per body plate. Ventral body surface whitish. Fins dark gray with light dots on rays, occasionally also on membranes (Fig.1). Some specimens with light dots almost imperceptible. Distribution. Known only from type-locality. The arroio Lageado Grande, tributary of the rio Erechim, rio Passo Fundo system (upper rio Uruguai basin), Rio Grande do Sul, Brazil (Fig. 5). Ecological notes. Type-locality for this species is a 2-5 m wide stream, with rocky and sandy bottom, small rapids separated by pools and marginal vegetation moderately preserved. Etymology. The specific name votouro (noun in apposition) is given in honor of the Votouro Indian Reserve, situated on Benjamin Constant, Rio Grande do Sul, Brazil.

Six species of Loricariidae belonging to the subfamilies Hypostominae (Hypostomus emarginatus, Rhinelepsis aspera, Pogonopoma wertheimeri), Ancistrinae (Panaque cf. nigrolineatus, Hemiancistrus sp.) and Loricariinae (Sturisoma cf. nigrirostrum) were studied cytogenetically. The results show that 2n = 54 represents the basal diploid number for this fish family. Different trends in the karyotypic evolution can be seen among the subfamilies: Hypostominae and Loricariinae species present diversified karyotypic macrostructures, while the Ancistrinae appear to show more conserved karyotypes. Among the Hypostominae, the genus Hypostomus had a wide karyotypic variation (2n = 52 to 80), where centric fissions seem to play an important role in this chromosomal divergence. The nucleolar organizing regions were diversified, and occurrence of multiple NORs was frequent. Heteromorphic chromosomes belonging to distinct sex chromosome systems can also occur infrequently among the Loricariidae.

The complete D-loop sequence was obtained from 23 Hypostomus and 12 other species belonging to eight genera, from which seven are closely related to Hypostomus. The phylogenetic analysis of these sequences indicates that the genus Hypostomus is polyphyletic due to the exclusion of H. emarginatus and H. squalinus from the main Hypostomus clade. Moreover, this main Hypostomus clade includes all Cochliodon species examined here, indicating that Cochliodon can be considered as a subjective junior synonym of Hypostomus. This conclusion is also supported by the placement of Hypostomus fonchii within the Cochliodon clade, implying that the synapomorphic characters diagnosing Cochliodon are unfounded. Based on these results, a new vision of Hypostomus is proposed. Furthermore, our results confirm the previously reported polyphyly of Ancistrinae and question the monophyletic status of Hemiancistrus.

Peckoltia sabaji is described based on specimens from the Guyana Shield regions of the Essequibo, Negro, and Orinoco River drainages of Guyana and Venezuela. Peckoltia sabaji is a member of the loricariid subfamily Hypostominae, tribe Ancistrini. The species differs from nearly all other members of the Hypostominae based on coloration — small spots on the head with spots becoming very large on the posterior part of the body. Those species with a similar coloration either do not have elongated bodies (vs. body very elongate) or have odontodes on the opercle as adults (vs. odontodes on opercle absent, rarely with one or two odontodes in adults).

Loricariid catfishes have evolved several modifications of the digestive tract that appear to function as accessory respiratory organs or hydrostatic organs. Adaptations include an enlarged stomach in Pterygoplichthys, Liposarcus, Glyptoperichthys, Hemiancistrus annectens, Hemiancistrus maracaiboensis, Hypostomus panamensis, and Lithoxus, a U-shaped diverticulum in Rhinelepis, Pseudorinelepis, Pogonopoma, and Pogonopomoides; and a ringlike diverticulum in Otocinclus. Scoloplacids, closely related to loricariids, have enlarged, clear, air-filled stomachs similar to that of Lithoxus. The ability to breathe air in Otocinclus was confirmed; the ability of Lithoxus and Scoloplax to breathe air is inferred from morphology. The diverticula of Pogonopomoides and Pogonopoma are similar to swim bladders and may be used as hydrostatic organs. The various modifications of the stomach probably represent characters that define monophyletic clades. The ovaries of Lithoxus were also examined and were shown to have very few (15-17) mature eggs that were large (1.6-2.2 mm) for the small

The ictiologic survery of the fauna of the Jacuí and Jacuizinho rivers, (RS – Brazil) lead to the identification of twenty species, Astyanax bimaculatus and Astyanax fasciatus and as well as Hemiancistrus sp being more abundant and uniformly distributed during the months of collet while Symbranchus marmoratus and Oligosarchus hepsetus were the more seldom found fishes.