Pseudancistrus sidereus, a new species from southern Venezuela (Siluriformes: Loricariidae) with a redescription of Pseudancistrus

Zootaxa ◽  
2004 ◽  
Vol 628 (1) ◽  
pp. 1 ◽  
Author(s):  
JONATHAN W. ARMBRUSTER

Pseudancistrus sidereus is described from two collections of specimens from Amazonas, Venezuela. Pseudancistrus sidereus differs from all other members of Pseudancistrus based on the presence of a unique keel on the caudal peduncle formed from the concave dorsal sections of the plates in the ventral series, light spots on the body (these may be yellow in life) centered on the body plates and the absence of the characteristics of the more derived members of Pseudancistrus such as hypertrophied odontodes along the snout in males and females and the loss of evertibility of the cheek plates. Pseudancistrus includes Lithoxancistrus and Guyanancistrus and is diagnosed by the following synapomorphies: no suture between pterotic-supracleithrum and hyomandibula, no contact of the hyomandibula with the prootic, straight, spoon-shaped anterior process of metapterygoid, nasal bone not much wider than laterosensory canal running through it, sphenotic not contacting posteriormost infraorbital externally, and a short ventral ridge on the pelvic basipterygium (lost in some species). Two species formerly assigned to Guyanancistrus are placed in different genera. Hypostomus guacharote is placed in Lasiancistrus and Chaetostomus trinitatis is placed in Ancistrus.Se describe Pseudancistrus sidereus, con base en dos colectas de espec menes del Amazonas venezolano. Pseudancistrus sidereus difiere de los otros miembros del g nero Pseudancistrus por la presencia de una quilla nica en el ped nculo caudal formada a partir de las secciones c ncavas dorsales de las placas de la serie ventral, puntos blancos en el cuerpo (probablemente amarillos en vida) centrados en las placas corporales y la ausencia de ciertas caracter sticas presentes en los miembros m s derivados de Pseudancistrus, como odontodos hiperatrofiados a lo largo del rostro en machos y hembras y la perdida de evertibilidad de las placas de la mejilla. Pseudancistrus incluye a Lithoxancistrus y Guyanancistrus y se diagnostica por las siguientes sinapomorf as: sutura entre el pter tico-supracleitro y la hiomand bula ausente, hiomand bula y pro tico sin contacto, proceso anterior del metapterigoides recto y en forma de cuchara, hueso nasal apenas m s amplio que el canal laterosensorial que corre a trav s del mismo, esfen tico sin contacto externo

2014 ◽  
Vol 12 (2) ◽  
pp. 333-342 ◽  
Author(s):  
Angela M. Zanata ◽  
Priscila Camelier

Characidium samurai, a species of the family Crenuchidae apparently endemic to rio das Almas and rio Vermelho basins, Bahia, Brazil, is described. The new species is readily distinguishable from its congeners, except C. lanei, by having a dark lateral band along the head and body that is particularly broad from the rear of the head to the end of the caudal peduncle (1.5 or 2 scales wide) and by the absence of dark bars or blotches on the ventral half of the body. Characidium samurai differs from C. laneiby having the lateral band with straight borders overall (vs.lateral band with somewhat irregular borders due to blotches extending dorsally or ventrally), anal fin ii,7-8 (vs. ii,6), and 4 horizontal scale rows above the lateral line and 4 below (vs. 5/3). It further differs from congeners by a series of features, including isthmus completely covered by scales, lateral line complete with 34-37 perforated scales, 9 scales on the transversal line, 14 scale rows around the caudal peduncle, anal fin ii,7-8, and the absence of dark bars or spots on the fins, except by a faded dorsal-fin bar. The presence of pseudotympanum in four species of Characidium is discussed.


Zootaxa ◽  
2018 ◽  
Vol 4461 (3) ◽  
pp. 438
Author(s):  
CARLOS AUGUSTO FIGUEIREDO ◽  
CRISTIANO R. MOREIRA

A new species, Poecilia (Pamphorichthys) akroa, is described from the Rio Tocantins drainage, Brazil. The new species differs from the remaining species of the genus by the possession of 10 or 11 pectoral-fin rays, entire preopercular ramus and posterior portion of the supraorbital ramus of the cephalic sensory system enclosed in canals, a faint longitudinal band along the body, a single gonapophysis, a homogeneous reticulate color pattern on sides of body, urogenital region of females heavily pigmented, distalmost segments of the anterior branch (4a) of the fourth gonopodial ray fused into an elongated segment turned anteriorly, subdistal segments of anterior branch (5a) of fifth gonopodial ray simple, without anterior (ventral) projections, dorsal fin with pigmentation at its distal portion and with a basal black blotch, and chromatophores more concentrated on the posterior margin of the mid-ventral scale series of the caudal peduncle and ventrolateral margin of the adjacent scales forming a series of rhombi posterior to anal fin. 


Zootaxa ◽  
2021 ◽  
Vol 4996 (2) ◽  
pp. 322-330
Author(s):  
HEOK HEE NG ◽  
MAURICE KOTTELAT

Pseudobagarius eustictus, new species, is described from the Nam Heung drainage (a tributary of the Mekong River) in northern Laos. It is distinguished from congeners in having a unique combination of the following characters: a weakly-produced snout in which the upper jaw extends only slightly beyond the margin of the lower jaw when viewed ventrally, 3 tubercles on the posterior margin of the pectoral spine, eye diameter 8% HL, head width 24.1% SL, dark yellow dorsal and lateral surfaces of the head, pectoral spine lacking elongate extensions, pectoral fin reaching the pelvic-fin base when adpressed against the body, dorsolateral surfaces of body without longitudinal series of prominent tubercles, body depth at anus 13.7% SL, length of adipose-fin base 17.7% SL, caudal-peduncle depth 7.0% SL, and 33 vertebrae.  


Zootaxa ◽  
2004 ◽  
Vol 546 (1) ◽  
pp. 1 ◽  
Author(s):  
FRANCISCO LANGEANI

Hemiodus jatuarana, a new species of the Hemiodontidae from Oriximin , rio Trombetas, Amazon Basin, Brazil, is described. The new species can be readily distinguished from its congeners by the presence of a horizontally elongated dark spot on the caudal peduncle, and by the absence of any other dark pigmentation pattern on the body. Hemiodus jatuarana is readily separated from H. immaculatus, another species without dark pigmentation on the body, by having 25 27 epibranchial and 36 37 ceratobranchial gill rakers on the first branchial arch, and caudal-fin lobes without longitudinal stripes, vs. 14 16 and 21 25 gill rakers, and a conspicuous longitudinal stripe on each caudal-fin lobe in H. immaculatus. The new species is only known from its type-locality, where it cooccurs with H. immaculatus.


Zootaxa ◽  
2010 ◽  
Vol 2496 (1) ◽  
pp. 63 ◽  
Author(s):  
LUÍS FELIPE TOLEDO

A new species of Elachistocleis (E. magnus) is described from the Amazon basin, in the municipality of Espigão do Oeste, state of Rondônia, Brazil. It differs from all other species of the genus by the combination of the following characters: i) size larger than 31 mm in adult males, ii) grayish ventral coloration, iii) presence of large post-commissural glands, iv) lack of red coloration in the body, and v) grayish dorsum in preserved individuals. There is dimorphism between males and females in size, structures and coloration. Vocalizations and larvae remain unknown.


2014 ◽  
Vol 12 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Cláudio H. Zawadzki ◽  
Pedro Hollanda Carvalho

A new species of Hypostomus, H. dardanelos, is described from the rio Aripuanã basin, a southern tributary to the rio Madeira, in northern Mato Grosso State, Brazil. The new species is assigned to the Hypostomus cochliodon group by the possession of few teeth, spoon-shaped teeth, angle between dentaries usually less than 80°, and by the absence of a notch between hyomandibular and the metapterygoid. The new species can be diagnosed from its congeners by its unique color pattern of yellowish-brown ground color covered by well-defined dark spots of relatively equal size, evenly spaced and moderately set along the dorsal region of the body and fins, except on the ventrolateral region of the caudal peduncle and proximal region of anal and caudal fins, which are devoid of spots. The new species is further diagnosed by having teeth with very small lateral cusp, fused to the mesial one and almost imperceptible; by the absence of medial buccal papillae, and by nuptial odontodes all along the body (odontodes more pronounced in some few larger specimens).


2016 ◽  
Vol 14 (1) ◽  
Author(s):  
William M. Ohara ◽  
Manoela M. F. Marinho

ABSTRACT A new species of Moenkhausia is described from the upper rio Machado at Chapada dos Parecis, rio Madeira basin, Rondônia State, Brazil. Among congeners, the new species is similar to Moenkhausia chlorophthalma, M. cotinho , M. lineomaculata , M. plumbea, and M. petymbuaba by having dark blotches on the anterior portion of the body scales, which are absent in the remaining species of the genus. The new speciesdiffers from aforementioned species by possessing blue eyes in life, 15-18 branched anal-fin rays, and a well-defined, round caudal-peduncle spot that does not reach the upper and lower margins of the caudal peduncle and does not extend to the tip of the middle caudal-fin rays.


Zootaxa ◽  
2011 ◽  
Vol 3134 (1) ◽  
pp. 53 ◽  
Author(s):  
DAVID W. GREENFIELD ◽  
SUSAN L. JEWETT

A new species of goby, Eviota rubriceps, most similar to E. nigrispina, is described from Indonesia, Papua New Guinea, and the Philippine Islands. Both species have the lower two thirds of the body dark in preserved specimens, belong to the cephalic sensory-pore pattern group 2 of Lachner and Karnella (1980), have an 8/7 dorsal/anal formula, and unbranched pectoral-fin rays. Eviota rubriceps differs from E. nigrispina in live and preserved coloration and in caudal-peduncle depth. The descriptions of E. mikiae and E. raja are expanded based on additional materials.


2013 ◽  
Vol 11 (2) ◽  
pp. 275-284 ◽  
Author(s):  
James Anyelo Vanegas-Ríos ◽  
María de las Mercedes Azpelicueta ◽  
Juan Marcos Mirande ◽  
María Dolly García Gonzales

A new species of Gephyrocharax is described from the río Cascajales basin, a tributary of the río La Colorada, río Magdalena system, Colombia. The new species is distinguished from its congeners, exceptG. melanocheir, by the absence of an adipose fin in most specimens and by the possession of a lateral branched pectoral-fin ray in males with a distal fan-shaped structure with minute bony hooks and a dark blotch or a few scattered dark brown chromatophores along its branches. The new species differs from G.melanocheir by the absence of an intense black pigmentation at the base of the anterior five dorsal-fin rays, the number of vertebrae (40-41vs. 38-39), the frontals contacting each other anterior to the epiphyseal bar in adults (vs. the absence of contact), the posterior margin of the mesethmoid straight in its central portion (vs. strongly concave at this point), the pouch scale of mature males reaching caudal-fin ray 11 or the area between caudal-fin rays 11 and 12 (vs. reaching only to caudal-fin ray 10 or the area between caudal-fin rays 9 and 10), the number of minute terminal branches of the lateral branched pectoral-fin ray of mature males (60-88 vs. 28-54), a longer black lateral stripe along the body in males (reaching to the base of the caudal-fin rays vs. reaching the middle of the length of the caudal peduncle), and the snout length (28.3-31.8% HLvs. 22.2-28.0% HL). The diagnosis ofGephyrocharax is modified to include species with the adipose fin variably present


Zootaxa ◽  
2019 ◽  
Vol 4560 (1) ◽  
pp. 164
Author(s):  
DANIARA COLPANI ◽  
CESAR JOÃO BENETTI ◽  
NEUSA HAMADA

Gyrinus rhyssonotum sp. n. is described and illustrated based on adult males and females collected in Barcelos County, Amazonas state, Brazil. The new species belongs to the subgenus Oreogyrinus Ochs, 1935 and it is compared with Gyrinus (Oreogyrinus) fittkaui Ochs, 1963 and G. (O.) opalinus Régimbart, 1883, both occurring in the Brazilian Amazonas and G. (O.) colombicus Régimbart, 1883 and G. (O.) venezolensis Ochs, 1954, these two latter alien to the Brazilian fauna but with which G. (O) rhyssonotum sp. n. seems to be more closely related, though the new species can be distinguished from both by a series of characteristics, mainly observed in the body shape, elytra, pronotum, and in male and female genitalia. 


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