170,046 research outputs found
Rineloricaria quilombola Chamon & Fichberg 2022, new species
No full textRineloricaria quilombola, new species (Figure 1, Table 1) Holotype. MZUSP 126901, 116.3 mm SL, Palmas, Taquaruçu, ribeirão Taquaruçuzinho na ponte para o povoado de Taquaruçu Grande, rio Tocantins drainage, -10.31555, -48.21638 16 April 2018, C. Chamon, J. Silva, I. Fichberg and E. Oliveira. Paratypes. All from Tocantins River basin. UNT 942, 3, 87.7 – 132.6 mm SL, córrego Imbé, Fazenda Traçadal, Paranã, -12.48333 -48.21666, 21 Mar 1999, Marques, E. et al. UNT 943, 3, 71.1 – 134.3 mm SL, córrego Cipó, Fazenda Traçadal, Paranã, -12.72805, -48.22944, 26 Jan 1999, Marques, E. et al. UNT 1094, 8, 54.3 –92.0 mm SL, ribeirão Manduca, Porto Nacional, -10.79416, -48.36666, 3 Oct 2001, Marques, E. et al. UNT 1713, 3, 44.0–110.3 mm SL, same locality as UNT 943, 4 Aug 2004, Marques, E. et al. UNT 1723, 6, 48.4 –75.0 mm SL, same locality and collect data of UNT 1713. UNT 15542, 2, 49.4 –114.0 mm SL, same locality of the holotype, 26 Jun 2016, Chamon, C., Oliveira, E., Silva, J. and Bezerra, C. UNT 15711, 6, 73.3 –97.0 mm SL, same locality as holotype, 18 Nov 2016, Chamon, C., Oliveira, E., Pereira, T., Silva, J. and Bezerra, C. UNT 15794, 2, 45.6 –50.0 mm SL, ribeirão Taquaruçu Grande, na chácara Irecê, Taquaruçu, Palmas, -10.31555, -48.21638, 15 Dec 2016, E. Oliveira and J. Silva. UNT 19246, 1, 61.2 mm SL, collected with the holotype. UNT 19262, 3, 59.6 – 111.5 mm SL, same locality of the holotype, 26 Apr 2016, Chamon, C., Oliveira, E. and Silva, J. UNT (uncatalogued), 4, 50.1–62.3 mm SL, ribeirão São João, Porto Nacional, -10.73660, -48.29243, 23 May 2022, Pelicice, F. Rocha, T., Fontoura, F., Parente, A.L. and Chamon, C. Non-types. UNT 945, 1, 98.6 mm SL, same locality of UNT 942, 26 Sep 2001, Marques, E. et al. UNT 956, 1, 107.6 mm SL, same locality as UNT 942, 25 Aug 1998, Marques, E. et al. UNT 1029, 20, 53.9 – 89.4 mm SL, córrego Taboca, Paranã, -12.5927778000, -48.1036111000, 7 Aug 2000, Marques, E. et al. UNT 1038, 1, 72.9 mm SL, same locality as UNT 945, 3 Oct 2001, Marques, E. et al. UNT 7190, same locality as UNT 942, 15 Aug 2005, Marques, E. et al. UNT 7911, 10, 40.0–77.6 mm SL, same locality of UNT 943, 24 Aug 2007, Marques, E. et al. Diagnosis. Rineloricaria quilombola is diagnosed among its congeners by a greater number of premaxillary teeth (up to 15 vs. up to 10 in all congeners, except R. aequalicuspis and R. castroi with 15; R. osvaldoi with 13 and R. uracantha with 12); and dentary teeth (up to 15 vs. up to 10 in all congeners, except R. aequalicuspis with 20, R. osvaldoi with 13; R. castroi and R. uracantha with 12). From R. aequalicuspis, it can be differentiated by having teeth with a principal inner cusp and an accessory smaller one (vs. teeth with inner and outer cusps of approximately the same size). From R. castroi, it is distinguished by color pattern without dark stripes on the pectoral, pelvic and anal fins (vs. pectoral, pelvic and anal fins with conspicuous dark stripes). From R. hasemani it is distinguished, by having the edge of snout straight in lateral view, absence of filaments on lower lip and by color pattern lacking a dark stripe on dorsal fin (vs. edge of snout upturned in lateral view, absence of filaments on lower lip and dark stripe on dorsal fin present). From R. lanceolata, by a wider body at cleithral width 16.5–20.1% of SL (vs. 13.8–16% of SL); presence of five lateral plates series in longitudinal rows below dorsal fin (vs. four lateral plates series); base of pectoral and pelvic-fins completely ochre or light brown without a hyaline area (vs. base of pectoral and pelvicfins with a hyaline circular area); and by the absence of a dark stripe in all fins, running parallel to the first rays (vs. dark stripe present). From R. osvaldoi, the new species is further diagnosed by a lower head depth (30.8–40.5 % vs. 42.2–61.3 % of HL), by having shorter snout length (45.5–51.4 vs. 50.3–68.8% of HL); triangular head in dorsal view (vs. rounded head in dorsal view); lower lip with elongated and organised rounded-shape fringes (vs. lower lip with short and unorganised triangular fringes); lower lip short not covering the gular area (vs. lower lip elongated, covering about 50% of the gular area); upper lip margin with long, rugged and regular papillae (vs. upper lip margin with short and inconspicuous papillae) (Fig. 2); head with regular rows of odontodes (vs. odontodes not forming regular rows); dimorphic male lateral head with short and spaced apart odontodes (vs large and very close hypertrophied odontodes). Description. Morphometric data in Table 1. Head and body strongly depressed. Dorsal profile of head triangular with tip of snout and distal margin of opercle rounded. Snout tip straight, not raised in lateral view. Snout with very small and elliptical naked area short and not reaching the first pore of infraorbital ramus of sensorial canal. Dorsal profile concave from tip of snout to dorsal-fin origin, and straight from this point to caudal-fin origin. Ventral profile straight from tip of snout tip to caudal-fin origin. Greatest body depth at the posterior border of supraocciptal; lowest body depth at caudal peduncle. Head short and very depressed. Odontodes of head small to moderate size, forming conspicuous ridges between nostrils on posterior nasal plates to posterior margin of parieto-supraoccipital and compound pterotic.Six infraorbital, infraorbital 1 with sensorial pore exposed ventrally, infraorbitals 2, 3 and 4 raised convexly from anterior region of snout to eye. Predorsal plates and first three lateral plates of dorsal series slightly keeled, covered with small odontodes. Eyes elliptical with a large and deep postorbital notch, slightly larger than half of the horizontal diameter of the orbit. Mouth opening large. Upper lip short and separated from the naked area of snout by an extremely thin row of plates covered by tiny odontodes; margin of upper lip adorned with long, rugged and regular papillae. Two rows of papillae between anteroventral border of upper lips and anterior border of premaxillary-ramus; lower lips covered by irregular sized papillae unorganised and regularly distributed around oral cavity; edge of lower lips with elongated and organised triangle-shape fringes. Maxillary barbel moderate in size, reaching the lower lip distal margin. Barbel adorned with very small papillae. Teeth acute and strongly bicuspidate; dentary teeth slightly larger than premaxillary; premaxilla with 8(8), 9(5), 10(3), 11(4)*, 12(1), 13(3) or 15(1) teeth and dentary with 8(6), 9(1), 10*(4), 11(7), 12(4), 13(1), 14(1) or 15(1) teeth; cuspids orange coloured, accessory cuspid almost the same size of principal one. Body covered by 27(7) or 28*(18) plates on median series, coalescence on 15(6), 16(9)* or 17 (10) and, 8(9), 9(9)* or 10(7) lateral abdominal plates. Mid-dorsal series with 2(15)*, 3(5) or 4(5) plates. Lateral line complete. Five longitudinal rows of plates at dorsal-fin origin. Lateral plates weakly keeled with odontodes along the lateral line pores slightly more developed than those at the rest of the body. Ventral region totally covered by plates from cleithrum to caudal peduncle. Ventral plates well organised in three sections. Anterior section with small, quadrangular plates on the pectoral girdle area. Second section includes large and trapezoidal plates between pectoral and pelvic girdles. Third section represented by the preanal shield formed by three large plates surrounding polygonal preanal plate. Dorsal fin (ii,7), dorsal-fin spinelet present, locking mechanism not functional. Dorsal-fin base with four to five plates. Pectoral fin (i,6), adpressed unbranched ray slightly surpassing pelvic-fin origin. Pelvic fin (i,5), depressed unbranched ray reaching anal-fin origin. Anal fin (i,5), with two plates on base. Caudal fin (i,10,i) emarginated, with short and thin filament on the upper caudal-fin ray. Lower caudal-fin ray filament absent. Coloration in alcohol (Fig. 3). Body background with light brown to beige coloration. Dorsal surface with five to six transverse dark brown bands: first one located at second or third dorsal-fin ray, extending toward pectoral-fin origin; second one at the distal edge of dorsal fin when adducted, extending toward to pelvic-fin origin; third one located at the distal edge of the pelvic fin when adducted; fourth, fifth and sixth ones located at caudal peduncle. First and second longitudinal bands occasionally faint, posterior ones darker and more conspicuous (Figs. 1 and 3). Second band occasionally wider in some specimens (Fig. 3A). Presence of sixth band on the caudal peduncle observed only in few specimens under 63 mm of SL (Fig. 3C). Dorsal surface of snout and head covered with irregular dark brown dots; more concentrated at nasal, frontal and posterior margin of the parieto-supraoccipital and compound pterotic. Posterior margin of compound pterotic with dark-brown to black tiny spots around the first pores of lateral-line canal. Specimens with less than 70 mm of SL present conspicuous dark brown lines between nostrils (along the nasal bones) and dark brown lines behind the postorbital notch and extending to supraoccipital (Fig. 3C). Lines less conspicuous or completely absent in larger specimens. Pores of sensorial canal of head and lateral line highlighted by dark brown or black chromatophores. Ventral surface background with beige coloration without dots, spots or bands (Fig. 1C). Dorsal surface of upper lip with two longitudinal light brown stripes, lower lip beige without dots or blotches. All fins with light brown or beige coloration covered with dark brown dots that usually run in parallel to fin-rays, dark spots could be faint on pelvic and anal fins; caudal fin with a conspicuous dark brown blotch on base and faint darker band on distal edge (Figs. 1 and 3). Coloration in life. Live coloration is very similar to color in alcohol, with a dorsal background ranging from ochre to grey and faint dorsal dark brown transversal bands. Dots and lines on snout and head are more conspicuous, as well as the dark brown dots on fins surface (Fig. 4). Sexual dimorphism. Head margin of mature males triangular, with short and spaced apart hypertrophied odontodes extending from postrostral plates to opercle, along margin of head; unbranched pectoral-fin ray and first four branched rays weakly covered dorsally by well-developed odontodes (Fig. 5). Distribution. The new species is known from upper and middle stretches of Tocantins River basin, in the municipalities of São Salvador, Paranã, Palmas (at Taquaruçu district) and Porto Nacional, Tocantins State, Brazil (Fig. 6). Ecological and conservation notes. Specimens from Taquaruçu were collected in streams (Taquaruçuzinho and Taquaruçu Grande, middle Tocantins River) with moderate to strong currents with clear water and background with rocks, stones, gravel and sand (Fig. 7A). Although the Palmas region is an area of influence of the Lajeado reservoir, at Taquaruçu district, the area is relatively preserved since it is sheltered within the environment protected area (APA) of Serra do Lajeado. Thus, these streams have preserved riparian forest in most of their courses. Still, there is concern due to water withdrawal of the headwaters for agricultural irrigation and recreation activities. Other localities where the species is distributed, include Cipó, Taboca and Imbé streams, that are located at the influence area of São Salvador and Peixe Angical reservoirs (upper Tocantins River), near the confluence of Paranã and Tocantins rivers; and Manduca and São João streams (Fig. 7B), located upstream Lajeado reservoir, at Porto Nacional municipality. Most of nearby areas of these streams were strongly altered by the implementation of reservoirs (e.g. São Salvador, Peixe Angical and Lajeado), and agricultural expansion. Even so, the streams are preserved with moderate riparian forest on its courses According to GeoCAT analysis, the new species Extent of Occurrence (EOO) is 4,822 km 2 and Area of Occupancy (AOO) is 28.000 km 2, based solely on these criteria, IUCN criteria suggest that the species is Endangered (EN). However, there was no capture effort since 2007, in addition, other biological aspects of the new species, such as population size and generational time are not known. Thus, we suggest that Rineloricaria quilombola should be categorised as deficient data (DD) according to the International Union for Conservation of Nature categories and criteria (IUCN, 2021). Etymology. The specific epithet (a noun in apposition) is in honour of all the remaining Quilombola population of the state of Tocantins, which hosts more than 40 communities called Quilombos. Quilombos were specifically communities created by fugitive enslaved African-Brazilian people in Brazil. These places became centers of resistance for enslaved people and their descendents. These communities are legally protected by the Brazilian government yet they are under constant threat related to the expansion of agribusiness and land speculation. Part of the distribution area of the new species is inserted or close to some of these communities.Published as part of Chamon, Carine C. & Fichberg, Ilana, 2022, Rineloricaria quilombola: a new species of whiptail catfish (Siluriformes, Loricariidae, Loricariinae) from upper and middle Tocantins River basin, Brazil, pp. 58-70 in Zootaxa 5194 (1) on pages 59-66, DOI: 10.11646/zootaxa.5194.1.3, http://zenodo.org/record/714189
Redescription of Acanthicus hystrix Agassiz, 1829 (Siluriformes: Loricariidae), with comments on the systematics and distribution of the genus
No full textChamon, Carine C. (2016): Redescription of Acanthicus hystrix Agassiz, 1829 (Siluriformes: Loricariidae), with comments on the systematics and distribution of the genus. Zootaxa 4088 (3): 395-408, DOI: 10.11646/zootaxa.4088.3.
Pseudacanthicus pitanga: a new species of Ancistrini (Siluriformes: Loricariidae: Hypostominae) from rio Tocantins Basin, North Brazil
No full textChamon, Carine C. (2015): Pseudacanthicus pitanga: a new species of Ancistrini (Siluriformes: Loricariidae: Hypostominae) from rio Tocantins Basin, North Brazil. Zootaxa 3973 (2): 309-320, DOI: 10.11646/zootaxa.3973.2.
FIGURE 3 in Pseudacanthicus pitanga: a new species of Ancistrini (Siluriformes: Loricariidae: Hypostominae) from rio Tocantins Basin, North Brazil
No full textFIGURE 3. Dorsal view of the cranium in Pseudacanthicus pitanga, MZUSP 34295, 236.3 mm SL, IO6 correspond to sixth infraorbital.Published as part of Chamon, Carine C., 2015, Pseudacanthicus pitanga: a new species of Ancistrini (Siluriformes: Loricariidae: Hypostominae) from rio Tocantins Basin, North Brazil, pp. 309-320 in Zootaxa 3973 (2) on page 315, DOI: 10.11646/zootaxa.3973.2.6, http://zenodo.org/record/23242
Pseudacanthicus pitanga Chamon, 2015, sp. nov.
No full textPseudacanthicus pitanga sp. nov. (Figs. 1–2; Tab. 1) Holotype. MZUSP 34296, 220.7 mm SL, Serra dos Carajás, bedrock at rio Itacaiunas, Serra dos Carajás, Pará, Brazil, 05032'00"W 0552'00"S, Nov 1983, M. Goulding. Paratypes. Brazil. Pará State. INPA 4502, 1, 164.1 mm SL, rio Tocantins, Tucuruí, 345 ' 39.16 "S, 4939 ' 50.85 "W, 0 1 May 1986, F. Martinho. INPA 4558, 4, 91.4–147.5, rio Tocantins, downstream to Tucuruí Dam, 346 ' 2.84 "S, 4939 ' 36.68 "W, 0 9 Oct 1984, G. M. dos Santos. INPA 4559, 1, 148.1 mm SL, poço do Paulo, rio Tocantins, Tucurui, 345 ' 31.63 "S, 4939 ' 50.75 "W, 26 Jul 1980, Equipe Ictiologia INPA (Lucia Rapp Py Daniel et al). INPA 6308, 1, 94.1 mm SL, Tucurui, downstream to Tucuruí Dam, 345 ' 58.19 "S, 4939 ' 43.57 "W. INPA 6311, 7, 30.2–230.3 mm SL, rio Tocantins, 345 ' 59.43 "S, 4939 ' 40.41 "W. INPA 6348, 1, 270.0 mm SL, rio Tocantins, Jatobal, 428 ' 26.61 "S, 4927 ' 18.23 "W, 0 5 Jul 1982, M. Jegu. INPA 6349, 1, 252.0 mm SL, Igarapé Jatobal, Tucuruí, 31 Oct 1980, Equipe Ictiologia INPA. INPA 6350, 1, 300.0 mm SL, rio Tocantins, Breu Branco, 44 ' 4.52 "S, 4938 ' 12.87 "W, 31 Oct 1980, Equipe Ictiologia INPA. INPA 10919, 1, 210.4 mm SL, rio Tocantins, downstream to Tucuruí Dam, 0345' 58 ”S, 04940' 21 ”W, 0 1 Nov 1980, Equipe Ictiologia INPA. MZUSP 24135, 1, 110.7 mm SL, rio Tocantins, lagoon in front of Jatobal, Jatobal, 04939'00"W 0434'00"S, 16 Sep 1970, Expediçao; à Permanente a Amazônia (Heraldo A. Britski et al.). MZUSP 34295, 6, 170.3 – 256.9 mm SL, 1 esq., 236,3 mm SL, rio Itacaiunas, Caldeirão, 05032'00"W 0552'00"S, 0 4 May 1983, M. Goulding. MZUSP 115275, 1, 181.1 mm SL, collected with the holotype. Tocantins State. UNT 857, 1, 170.1 mm SL, rio Tocantins, Brejinho de Nazaré, 115 ' 24 "W 4834 ' 19 "S, 17 Nov 1997, Equipe Neamb (Anderson B. Soares et al). UNT 960, 1, 200.7 mm SL, rio Tocantins, Brejinho de Nazaré, 115 ' 24 "W 4834 ' 19 "S, 18 Set 2003, Equipe Neamb. UNT 967, 1, 87.3 mm SL, rio Tocantins, Fazenda Traçadal, Paranã, 1228 '099"W 4814 ' 47 "S, 27 Jul 1999, Equipe Neamb. UNT 8505, 1, 259.0 mm SL, rio Tocantins, near the confluence with rio Santo Antônio, Peixe, 1131 ' 17 "W 4837 ' 59 "S, 17 Oct 2001, Equipe Neamb. UNT 9061, 1, 224.2 mm SL, rio Maranhão at the place of UEH São Salvador, São Salvador, 1248 ' 55 "W 4814 ' 45 "S, 18 Jun 2006, A. Santana. UNT 1109, 1, 146.8 mm SL, rio Sono, Pedro Afonso, 859 ' 54 "W 4814 ' 17 "S, 10 Ago 2001, Equipe Neamb. UNT 10297, 1, 228.5 mm SL, rio Tocantins, border of Miracema and Tocantínia, 942 ' 59 "W 4821 ' 39 "S, May 2009, Equipe CMT Ambiental. Non-type material. Brazil, Pará state, rio Tocantins. ZMA 119.395, 3, 88.5–89.2 mm SL, Tucuruí, about 2 km below dam, 346 ' 29.47 "S 4939 ' 9.64 "W, 9 Oct 1984, G. Mendes dos Santos. ZMA 119.829, 1, 82.8 mm SL, Cametá, 0214'S, 04930'W, Jul 1985, A. Werner. No data. AMNH 97659, 1, 82.8 mm SL. Diagnosis. Pseudacanthicus pitanga, sp. nov., is distinguished from its congeners (except P. leopardus) by its color pattern with intense orange to red fins (vs. dark background color with white spots in P. serratus and P. fordii or gray background color with black blotches in P. histrix and P. s pi n os u s). It can be distinguished from P. leopardus by the presence of dark blotches anostomosing to form continuous zigzag bands alongside longitudinal keels; absence of blotches on ventral surface of body; faint blotches on head and all fins with orange to red color on unbranched ray and sometimes on subsequent branched rays (dark blotches conspicuous, never anostomosed; large dark blotches on ventral surface; conspicuous dark blotches on head; and red color restricted to dorsal and caudalfin rays). Pseudacanthicus pitanga can be further diagnosed from congeners by the following combination of osteological characters: contact of sphenotic with sixth infraorbital absent (Fig. 3; vs. present in remaining species), lateral surface of metapterigoid channel triangular (vs. rounded in remaining species), posterior area of contact between cleithrum and coracoid ventrally expanded (vs. straight in remaining species). Description. Morphometric and meristic data summarized in Table 1. Dorsal profile of body slightly convex from tip of snout to vertical through dorsal-fin origin; concave, nearly straight from that point to caudal-fin origin. Ventral profile of body straight from snout tip to caudal-fin origin. Ventral surface from tip of snout to urogenital papillae lacking plates, except for few small plates at pectoral- and pelvic-fin origins. Greatest body width at pectoral girdle. Trunk strongly keeled; five rows of keels; each one along each body plate series. Greatest body depth at dorsal-fin origin, body most slender at caudal peduncle. Head tall, pointed anteriorly, somewhat triangular in dorsal view; snout and cheek completely covered by numerous small plates, except for small naked area on tip of snout. Snout very pointed in dorsal view. Nasal bone rectangular, thin and elongate (Fig. 3). Frontal bone short, slightly contacting nares anteriorly and orbit posteriorly (Fig. 3). Anterior margin of frontal short, reaching posterior margin or half nare length (Fig. 3). Parietosupraoccipital enlogate, its posterior edge narrow, with V-shaped crest (Fig. 3). Sphenotic short, not contacting IO 6, with conspicuous odontodes (Fig. 3). Orbit small to moderate in size (9,6–16,4% HL), positioned dorsolaterally. Iris with small, dorsal flap over pupil. Pterotic-supracleithum short, with few fenestrae, its anterior process contacting a small region of posterior margin of orbit. Posterior area of pterotic-supracleitrhum with one or two small sized plates. Infraorbital series with 8 pores. Infraorbital 4 widely contacting posterior margin of orbit. Infraorbital 6 associated with only the posteroventral margin of orbit. Lateral line pores restricted to hypural plate. Mouth moderate in size, nearly as long as wide. Lips large, covered with papillae; size of papillae decreasing towards posterior margin of lower lip; central buccal papilla absent or little developed. Upper lip folded over itself. Maxillary barbel short; base of barbel united to lips, with free tip. Lower lip not reaching anterior margin of coracoid. Medial end of premaxillary teeth curved inwards. Premaxillae and dentary narrow and elongate. Dentary strongly curved inwards. Teeth slightly thick, well-developed, with long crown and large lateral cusp; its distal edge slightly curved inwards. Four to five pairs of predorsal plates. Cheek plates eversible, with hypertrophied odontodes. Dorsal-fin rays i, 8, pterygiophores located posterior to neural spines of vertebral centra 6–17. Dorsal-fin base very long, its length equals to 12 dorsal plates, reaching pre-adipose plate; connected to adipose fin by thick membrane. Dorsal-fin spinelet V-shaped with locking mechanism. Eight furcate neural spines supporting dorsal fin. Pectoral and pelvic fins well developed, medial portion conspicuously expanded relative to base; distal margin rounded. Pectoral-fin rays I, 6; unbranched ray covered with well-developed odontodes. Tip of adpressed pectoral fin almost reaching vertical through medial, unbranched, pelvic-fin ray. Pelvic-fin rays i, 5; pelvic-fin spine reaching vertical through anal-fin base when adpressed. Anal-fin rays i, 4, located posterior to haemal spines of vertebral centra 14–17. Caudal fin i, 14, i, truncate; caudal fin-ray filaments present in juveniles; supracaudal plates 7. Three to five (usually four) procurrent caudal-fin rays. Total vertebrae 29, precaudal 12. Sixth rib strongly thickened, remaining ribs slender. Color in life. Dorsal surface of trunk pale brown with median dark blotches that might be faint in juveniles and some adults; dark blotches anostomosing to form continuous zigzag bands alongside longitudinal keels in most specimens. Head without well-defined spots or blotches. Ventral surface pale, sometimes with some few faint spots in the abdominal region; spots in general absent in most specimens. All fins with orange or almost red color, at least in the unbranched fin-rays; more evident in the dorsal and caudal unbranched fin-rays. Juvenile specimens (in most cases) with dorsal and caudal fin almost completely faint orange without dark blotches. Color in alcohol. Specimens in alcohol usually exhibit the same color pattern when live, but in most cases the orange coloration of fins and blotches on body are inconspicuous and faint. Distribution. Pseudacanthicus pitanga probably occurs throughout the median and lower rio Tocantins. The species was recorded in the lower Tocantins river basin, at Serra dos Carajás, Tucuruí and Cametá, Pará state, and median Tocantins river basin, between São Salvador and Lajeado, Tocantins state (Fig. 4). Fisheries and economic importance. Because of its flashy and beautiful color pattern, the species of Pseudacanthicus, although not formally described, are very well known by local fishermen and the aquarist community, being an economic resource in some cases. Specimens of Pseudacanthicus pitanga, like other ornamental species, are exported to several countries worldwide, especially in Europe and the U.S.A., which has enabled many aquarists to breed them (E. Bertelsen, pers. comm.). Pseudacanthicus pitanga is economically important in the aquarium trade as an ornamental fish. The ornamental fish exploration has been a common practice in lower Tocantins in the Marabá region, and P. pitanga is recognized in the L number aquarist system as L024 (Schraml & Schaefer, 2004). Ornamental fishes are usually captured by diving with the aid of an air compressor, a collecting technique that is very common in ornamental fish exploration centers, such as in Marabá (Tocantins), Altamira (Xingu), and Santarém and Itaituba (Tapajós) (more about capture techniques in Sousa & Birindelli, 2009). Etymology. The specific epithet pitanga derives from Tupi-Guarani, meaning red, in allusion to the color of fins. An adjective.Published as part of Chamon, Carine C., 2015, Pseudacanthicus pitanga: a new species of Ancistrini (Siluriformes: Loricariidae: Hypostominae) from rio Tocantins Basin, North Brazil, pp. 309-320 in Zootaxa 3973 (2) on pages 310-314, DOI: 10.11646/zootaxa.3973.2.6, http://zenodo.org/record/23242
FIGURE 1 in Rineloricaria quilombola: a new species of whiptail catfish (Siluriformes, Loricariidae, Loricariinae) from upper and middle Tocantins River basin, Brazil
No full textFIGURE 1. Holotype of Rineloricaria quilombola, n. sp. MZUSP126901, 116.3 mm SL, in A. dorsal, B. lateral and C. ventral views.Published as part of Chamon, Carine C. & Fichberg, Ilana, 2022, Rineloricaria quilombola: a new species of whiptail catfish (Siluriformes, Loricariidae, Loricariinae) from upper and middle Tocantins River basin, Brazil, pp. 58-70 in Zootaxa 5194 (1) on page 60, DOI: 10.11646/zootaxa.5194.1.3, http://zenodo.org/record/714189
Toric-boson model: Toward a topological quantum memory at finite temperature
No full textWe discuss the existence of stable topological quantum memory at finite temperature. At stake here is the fundamental question of whether it is, in principle, possible to store quantum information for macroscopic times without the intervention from the external world, that is, without error correction. We study the toric code in two dimensions with an additional bosonic field that couples to the defects, in the presence of a generic environment at finite temperature: the toric-boson model. Although the coupling constants for the bare model are not finite in the thermodynamic limit, the model has a finite spectrum. We show that in the topological phase, there is a finite temperature below which open strings are confined and therefore the lifetime of the memory can be made arbitrarily (polynomially) long in system size. The interaction with the bosonic field yields a long-range attractive force between the end points of open strings but leaves closed strings and topological order intact
FIGURE 6 in Rineloricaria quilombola: a new species of whiptail catfish (Siluriformes, Loricariidae, Loricariinae) from upper and middle Tocantins River basin, Brazil
No full textFIGURE 6. Distribution map of Rineloricaria quilombola. White circle corresponds to the type locality.Published as part of Chamon, Carine C. & Fichberg, Ilana, 2022, Rineloricaria quilombola: a new species of whiptail catfish (Siluriformes, Loricariidae, Loricariinae) from upper and middle Tocantins River basin, Brazil, pp. 58-70 in Zootaxa 5194 (1) on page 65, DOI: 10.11646/zootaxa.5194.1.3, http://zenodo.org/record/714189
Can We Predict the Next Capital Account Crisis?; ; November 9 and 10, 2006
No full textThis paper uses binary classification trees (BCTs) to predict capital account
crises. BCTs successively compare candidate variables and thresholds to split
the data into two subsamples, allowing for a large number of indicators to be
considered and complex interactions to emerge in a way that standard
regressions cannot easily replicate. We identify a robust leading indicator role
for three variables (international reserves, current account balance, and shortterm
external debt) as well as a reserve cover measure that combines them.
External indebtedness and domestic GDP growth forecasts are also important
predictors of vulnerability. Out of sample, we were able to capture some of the
main emerging market crises with relatively few false alarms but the overall
out-of-sample performance of our forecasts was mixed. Global cyclical
variables help explain vulnerability to crises but they are difficult to predict
and, therefore, are of limited use for forecasting purposes
Theory of the superglass phase
No full textA superglass is a phase of matter which is characterized at the same time by superfluidity and a frozen amorphous structure. We introduce a model of interacting bosons in three dimensions that displays this phase unambiguously and that can be analyzed exactly or using controlled approximations. Employing a mapping between quantum Hamiltonians and classical Fokker-Planck operators, we show that the ground-state wave function of the quantum model is proportional to the Boltzmann measure of classical hard spheres. This connection allows us to obtain quantitative results on static and dynamic quantum correlation functions. In particular, by translating known results on the glassy dynamics of Brownian hard spheres we work out the properties of the superglass phase and of the quantum phase transition between the superfluid and the superglass phase
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