Pectoral-fin Spine Research Articles

Pseudobagrus fui Miao, a valid bagrid species from the Yangtze River drainage, South China (Teleostei: Bagridae)

Pseudobagrus fui Miao is a valid bagrid species that can be separated from all its congeners in having 27–33 anal-fin rays. Among the species of Pseudobagrus, it forms part of a group of approximately 20 species putatively characterized by having a smooth anterior margin of the pectoral-fin spine and short maxillary barbels not extending to the base of the pectoral-fin spine. Pseudobagrus fui, together with P. nitidus and P. vachelli, can be differentiated from all other forktailed species of this group by having no fewer than 20 branched anal-fin rays, the posterior end of the anal-fin base posterior to the vertical through the posterior end of the adipose-fin base, and anal-fin base longer than the adipose-fin base. It further differs from P. nitidus in having a gas bladder without beaded lateral and posterior margins, and from P. vachelli in having short maxillary barbels not extending to the base of the pectoral-fin spine. Pseudobagrus fui is currently known from the main stream of the upper Yangtze River and its tributaries, the Min River, Jialing River, Tuo River, Wu River and Chishui River in Sichuan Province, Guizhou Province, and the Chongqing City. The identity and nomenclature of Pseudobagrus nitidus is also discussed.

Lake Sturgeon Age Validation using Bomb Radiocarbon and Known‐Age Fish

AbstractPectoral fin spines have been the accepted structure for estimating the age of various sturgeon species for nearly 100 years, though other structures have also been used (otoliths, pectoral girdle, scutes, and caudal fulcra). Accuracy of age estimates using any of these structures has not been validated, so we report the first use of bomb radiocarbon (14C) assays to assess the validity of ages estimated using growth increments on pectoral fin spine and otolith frontal cross sections from lake sturgeon Acipenser fulvescens; we also assessed age estimates from pectoral fin spines of known‐age lake sturgeon. Growth increments on pectoral fin spine cross sections underestimated true age of fish older than 14 years and error increased with age, whereas otoliths accurately estimated true age up to at least 52 years. Increment formation on pectoral fin spine and otolith cross sections from juvenile lake sturgeon (ages 2‐11) was similar, although pectoral spines were clearer and easier to interpret. A power function (true age = [estimated age]1.054796, where estimated age was determined from pectoral spines; r2 = 0.98) provides a means for correcting existing age estimates obtained from lake sturgeon pectoral fin spines.

A new species of Liobagrus (Siluriformes: Amblycipitidae) from Southern China

We describe a new species of amblycipitid catfish, Liobagrus aequilabris, from the Xiangjiang, a tributary of the Changjiang (=Yangtze River), in Guangxi province of southern China. Liobagrus aequilabris differs from its congeners by a novel combination of characters that includes: lack of large, retrorse serrations on the posterior edge of the pectoral-fin spine, having upper and lower jaws of equal length, relatively long dorsal (7.5–10.2% SL) and pectoral-fin (9.1–12.1% SL) spines, a relatively long caudal fin (20.1–26.9% SL), and relatively few post-Weberian vertebrae (35–37). This species is only known from the Xiangjiang, but may also be present in the Lijiang, a tributary of the Zhujiang (=Pearl River), due to the presence of the Lingqu canal, which connects the Xiangjiang and Lijiang.New taxon: Liobagrus aequilabris Wright and Ng

A new species of Gelanoglanis (Siluriformes: Auchenipteridae) from the Marañon River (Amazon Basin), northeastern Perú

ABSTRACT We describe a new species of driftwood catfish, Gelanoglanis travieso, (Siluriformes: Auchenipteridae) from the Maranon River, a whitewater tributary of the Amazon River in northeastern Peru. It shares with the two described species in this genus, G. stroudi, from left bank whitewater tributaries of the Orinoco River in Colombia and Venezuela, and G. nanonocticolus from blackwater tributaries of the upper Orinoco and Negro Rivers in Amazonas, Venezuela and northern Brazil, the following synapomorphies: reduced size, compressed body, conical snout, a single pair of mental barbels, premaxillae widely separated at rostral border of upper jaw, premaxillary and dentary tooth patches narrow, posterior naris long and narrow and positioned immediately anterior to orbit, and small eyes. Gelanoglanis travieso differs from all congeners in having second dorsal-fin lepidotrichium filamentous, simple, not a spine, and not serrate (shared with G. nanonocticolus); pectoral-fin spine stout, serrate along posteri...

A new species of Hemiancistrus from the rio Araguaia basin, Goiás state, Brazil (Siluriformes: Loricariidae)

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.

Two new species of Hypostomus Lacépède (Teleostei: Loricariidae) from the upper rio Paraná basin, Central Brazil

Two new species of Hypostomus Lacépède (Teleostei: Loricariidae) from the rio Paranaíba and rio Grande basins, both in the upper rio Paraná basin, central Brazil, are described herein. One of them is distinguished from all congeners, except H. albopunctatus, by having the pectoral-fin spine length equal to or smaller than the pelvic-fin spine. From H. albopunctatus, it is distinguished by having round dark spots (vs. pale) on body and fins. The second species is distinguished from all congeners, except H. multidens and H. ternetzi, by having more than 115 teeth (vs. less than 109) per ramus on dentary and premaxilla. It is distinguished most readily from H. ternetzi by having teeth with two symmetrical (vs. asymmetrical) cusps. It is distinguished from H. multidens by having round dark spots (vs. pale) over body and fins.

A new species of Gladioglanis Ferraris & Mago-Leccia from rio Aripuanã, Amazonas, Brazil (Siluriformes: Heptapteridae)

A new species of Gladioglanis is described from a single locality on rio Aripuanã, rio Madeira basin, and can be distinguished from its congeners by the following characters: dorsal-fin spine and spinelet absent, first dorsal-fin ray flexible, unbranched, followed by five branched dorsal-fin rays, pectoral-fin spine short and with few (5 anterior-side, 4 posterior-side) dentations, 22-25 anal-fin rays, round profile of the head in dorsal view, first dorsal-fin pterygiophore in contact with the neural spine of eighth vertebrae, 13 caudal-fin rays in both upper and lower lobes, and 60 total vertebrae. Some of its characters are discussed below and compared among the species of a small clade within Heptapteridae proposed by Bockmann (1998).

Flooded flatheads: evidence of increased growth in Mississippi River Pylodictis olivaris (Pisces: Ictaluridae) following the Great Midwest Flood of 1993

Both the Mississippi and Missouri rivers experienced major flooding in the spring and summer of 1993, inundating much of their floodplains for long periods, and allowing fish access to vast but previously inaccessible benthic foraging areas. In response to the latter, we hypothesized that flathead catfish (Pylodictis olivaris) would exhibit altered post-flooding growth as compared to like-aged fish whose lives were flood-free. To test this hypothesis, we obtained the left pectoral fin spines from hoop-netted Mississippi River flathead catfish collected in the vicinity of Crystal City, Missouri, USA, and conducted an individual-based back-calculated growth comparison of individuals captured pre-flood (1991) and post-flood (1996). For like-aged cohorts, our back-calculated length-at-age data clearly show that the post-flooding growth in 1996-collected fish was superior to that of the 1991-collected fish that had experienced less exceptional flow regimes. This outcome suggests that increased forage or/and foraging opportunities can be a consequence of flooding, and that flathead catfish are able to capitalize on this. The natural flooding regime of big rivers may thus be an important contributor to the growth and success of certain fish species; consequently, modifying the river’s natural hydrograph and channel morphology may be detrimental.

Description of Cathorops manglarensis, a new species from the Colombian Pacific, with redescription of Cathorops multiradiatus (Siluriformes; Ariidae)

Since it was described, Cathorops multiradiatus has been differentiated from congeners through the large number of anal-fin rays ( 25 - 27). In this study, C. multiradiatus is redescribed and a new sympatric species with similar number of anal-fin rays is described and intersexual differences of both species evaluated. Cathorops manglarensis differs from C. multiradiatus by possessing few gill rakers on the first arch ( 13 - 16 vs. 16 - 19), a longer maxillary barbel (28.4 - 38.2 vs. 22.9 - 27.7% SL), longer pectoral-fin spine (18.5 - 22.5 vs. 16.9 - 18.7% SL), posterior margin of pectoral-fin spine with short and inconspicuous serrations ( vs. posterior margin of pectoral-fin spine with long and conspicuous serrations), dorsal-fin spine shorter than pectoral-fin spine ( vs. dorsal-fin spine longer than pectoral-fin spine), and large accessory tooth plates with large and numerous molariform teeth ( vs. small accessory tooth plates with small and few molariform teeth). The nominal species Tachysurus emmelane and Tachysurus equatorialis are considered junior synonyms of C. multiradiatus and a key to species of Cathorops from the Pacific coast of Central and South America is provided.

Effect of oral suction and other friction-enhancing behaviors on the station-holding performance of suckermouth catfish (Hypostomusspp.)

Effect of oral suction and other friction-enhancing behaviors on the ability to maintain position in a current (station-holding) was determined for the suckermouth catfish (genus Hypostomus Lacépède, 1803). Fish were tested using an increasing velocity test on three substrata (smooth Lucite®, rough Lucite®, and wire grid). On the smooth substratum, use of oral suction and other behaviors delayed the need to swim continuously out of ground contact from 9.1 ± 0.3 cm/s (uslip) to 89.2 ± 7.9 cm/s (uswim). Trials on the wire grid showed that oral suction was ineffective as predicted; however, fish were able to use other friction-enhancing behaviors instead to improve station-holding performance. Behaviors that increased friction by hooking the fish to the substrate via the odontodes and pectoral fin spines were very effective at delaying the need for steady swimming from 12.9 to 145.0 cm/s. On the rough substratum, fish were able to use both oral suction and the odontodes or fin spines to increase friction, and station-holding performance was similar to values on the wire substratum. Thus, while use of the oral suction disk was shown to improve station-holding performance, use of other morphological features such as the odontodes and fin spines may be equally important.

Two new species of Isbrueckerichthys Derijst, 1996 (Siluriformes: Loricariidae) from the rio Paranapanema basin, Brazil

Two new Isbrueckerichthys species from Paranapanema river basin are described, I. saxicola and I. calvus, respectively from ribeirão Jacutinga and rio Taquara affluents. Both species present all diagnostic characters of the genus, and differ from their congeners by having bicuspid teeth (vs. simple teeth in I. alipionis), hypertrophied odontodes along the lateral margin of head (vs. hypertrophied odontodes only at the anterior portion of snout in I. epakmos) and longer pectoral-fin spine and shorter caudal peduncle length in relation to I. duseni. The new species can be distinguished from each other by number of odontodes in each minute abdominal platelet (more than six in I. saxicola vs. at most six in I. calvus); by the presence of a plated area under the three first plates of the lateral line in I. saxicola vs. its absence in I. calvus in which this region is naked; by a exposed portion of cleithrum bordering the entire margin of the opercular opening in I. saxicola vs. bordering just the superior portion in I. calvus; and by presenting the exposed surface of supraoccipital plain or slightly convex in I. saxicola vs. strongly convex with an area without odontodes on the center in I. calvus.

Anatomy of the early Devonian acanthodian Brochoadmones milesi based on nearly complete body fossils, with comments on the evolution and development of paired fins

ABSTRACT New anatomical details are described for the acanthodian Brochoadmones milesi based on nearly complete body fossils from Lochkovian rocks at MOTH, Mackenzie Mountains, Northwest Territories, Canada. The body and caudal peduncle are deep, and a prominent nuchal hump is present before the dorsal fin origin. The caudal fin is correspondingly deep and ventrally, the caudal fin lies close to and is partly joined to the slender anal fin. A delicate pectoral fin trails the flattened pectoral-fin spine where previously known specimens showed only a fin spine resembling a bivalve shell. Seen for the first time in any vertebrate, each of the six pairs of prepelvic spines supports a small, scale-covered finlet. Both prepelvic spines and scale-covered finlets increase in size posteriorly. The series of paired prepelvic finlets originates ventral to the branchial chamber and anteroventral to the pectoral fin, and extends posteriorly as far as the pelvic fins. The scales of the body and fins are thin and flat, without obvious evidence of ossified basal tissue or entry point for vascular tissue. The main lateral-line canal passes dorsal to the branchial chamber and terminates at the trailing edge of the caudal fin web. Lateral-line scales are thicker than body scales and show concentric growth zones. Scales from the dorsal midline of the caudal fin are also thicker, showing few superpositional growth zones in the mesodentine of the crown together with what appears to be cellular basal tissue. The structure and position of the pectoral spine and fin, the extremely thin body scales, the slender anal fin, and the prepelvic finlets are all unique and appear to be autapomorphic features compared to those of other acanthodians. Brochoadmones milesi is derived relative to other fishes traditionally classified in the Climatiiformes. Kathemacanthus rosulentus is removed from the Brochoadmonoidei, leaving only B. milesi in a monotypic suborder.

Microglanis pataxo, a new catfish from southern Bahia coastal rivers, northeastern Brazil (Siluriformes: Pseudopimelodidae)

A new pseudopimelodid catfish of the genus Microglanis, collected in small rivers at the lower and middle Peruípe, middle Jucuruçu and Cahy basins, in the southeastern coast of the Bahia state, is described. The new species has a comparatively high number of anal fin proximal radials, 12, shaped as thin tubes, the last one bearing a laminar extension; a pectoral fin spine with a bony point and with a smaller number of serrations on its posterior border; seven pleural ribs and a narrow head width. We provide information on the external morphology and also on some osteological features for the new species. A key to species is presented for the coastal drainages between Rio de Janeiro and Bahia states.

A New Species ofPseudomystus(Teleostei: Bagridae) from Central Vietnam

Pseudomystus sobrinus, a new species of bagrid catfish, is described from small coastal streams draining the eastern slope of the Annam Cordillera in central Vietnam. Pseudomystus sobrinus resembles P. siamensis and P. bomboides; all three species are distinguished from congeners by their color pattern of strongly contrasting brown and yellow/cream vertical bands on the body. Pseudomystus sobrinus differs from P. siamensis in having a slightly bulbous snout, shorter adipose-fin base (14.7–19.9% SL vs. 21.3–27.2) and pectoral-fin spine (15.4–18.3% SL vs. 17.8–23.4), and from P. bomboides in having a shorter maxillary barbel (not reaching beyond opercle vs. reaching beyond base of pectoral-fin spine) and one (vs. two) brown bands on the caudal fin.

Geographical and Temporal FA Variation in Threespine Stickleback Populations from Galicia (NW Spain)

Subtle departures from bilateral symmetry (FA) in morphological traits has been used as a measure of developmental stability in populations subjected to genetic and environmental processes as inbreeding, pollution or parasitic infection. Geographic variation of FA was assessed in 19 threespine stickleback (Gasterosteus aculeatus) populations from Mino and Limia rivers, from Galicia (NW Spain). This variation was evaluated using four FA indices on five meristic and one morphometric traits. Temporal variation of FA was also assessed using several samples through time in only one population. Significant geographical variation was detected for pectoral fin rays, lateral forks, lateral plates and spine length. Lateral plates, upper gillrakers, pectoral fin rays and spine length showed significant variation through the time. The variation of FA through the time showed a common performance for all characters during the period considered: a slight increase in the intermediate months with a decrease at the end of the period. Symmetric and asymmetric sticklebacks exhibited similar infection, with one exception: symmetric sticklebacks for lower gillrakers of Antela populations exhibited increased parasite infection relative to asymmetric ones. Sticklebacks with extreme phenotypes exhibited much higher levels of asymmetry than modal ones in all samples for all traits.

Two new species of Pseudolaguvia (Teleostei: Erethistidae) from Bangladesh

Two new South Asian catfish species of the family Erethistidae, Pseudolaguvia inornata and Pseudolaguvia muricata, are described from the Brahmaputra and Feni River drainages in Bangladesh. Pseudolaguvia inornata from the Feni River drainage can be distinguished from congeners in having a uniform coloration with a pale mid-dorsal stripe and brown submarginal stripes on each lobe of the caudal fin, while P muricata from the Brahmaputra River drainage can be distinguished from congeners by its elongate dorsal and pectoral-fin spines.

Resurrection of Pareiorhaphis Miranda Ribeiro, 1918 (Teleostei: Siluriformes: Loricariidae), and description of a new species from the rio Iguaçu basin, Brazil

A new species of the loricariid subfamily Neoplecostominae is described on the basis of specimens obtained from the headwaters of the rio Iguaçu basin in the State of Paraná, southern Brazil. Pareiorhaphis parmula is the first representative of the genus discovered from the rio Paraná basin and expands the geographic distribution of the genus. It is diagnosed from other Pareiorhaphis species by having one small plate on each side of the pectoral girdle, just posterior to the gill opening and the club-shaped pectoral-fin spine, broadening from base to tip in adult males. All species formerly included in Hemipsilichthys except H. gobio, H. papillatus, and H. nimius are transferred to the genus Pareiorhaphis, which is resurrected from the synonymy of Hemipsilichthys.

Age and growth of the porthole shovelnose catfish (Hemisorubim platyrhynchos) in the Pantanal

The porthole shovelnose catfish, Hemisorubim platyrhynchos, is the sixth largest pimelodidae of the Pantanal. Its age and growth were studied using pectoral fin-spines from fish collected in the Cuiabá river basin, Pantanal. The fish, which came from commercial and experimental fisheries, were all caught with hook and line. Growth-ring formation time could not be defined through the Kruskal-Wallis test on marginal increment (H = 4.142; p = 0.247). Nevertheless, decrease in the marginal increment index occurring as waters recede suggests this as the probable time when growth rings form. Estimation of the parameters of von Bertalanffy growth curve, adjusted through nonlinear regression to observed fork lengths, with L(infinity) fixed at 64 cm, were: k = 0.222 year(-1); t(o) = -2.149 years. Individual life span was estimated at 11.4 years. The results suggest that fork length is a good predictor of age for individuals of this species.

Spatial distribution and interaction of four species of the catfish genus Hypostomus Lacépède with bottom of Rio São Francisco, Canindé do São Francisco, Sergipe, Brazil (Pisces, Loricariidae, Hypostominae)

The large catfishes, genus Hypostomus Lacépède, are common species in almost all freshwater environments of South America. The behavior of specimens from the species Hypostomus alatus, Hypostomus francisci, Hypostomus cf. wuchereri, and Hypostomus sp., from the region downstream from the Xingó Hydroelectric Power Dam, located in Canindé do São Francisco on the Rio São Francisco, were observed. Morphological characters collected from preserved specimens were also studied in the laboratory, in order to shed light on interactions between those fishes and the river bottom. In addition, the formulation of Gatz (1979) was applied to better explain the environmental interactions of Hypostomus species. This study revealed that the fishes utilize their suckers, through a mouth equipped with an oral disk, as well as the pectoral, pelvic, and caudal fins areas, to interact with the rocky river-bottom. The comb-toothed inferior mouth of the Hypostomus showed itself able to grasp green algae on the river bottom. With the help of the oral disk and sucker mouth, which anchor the fishes, in conjunction with the arched design of pectoral and pelvic fin spines, they are also able to remain upright while exploring this substratum. In addition, their large, concave caudal-fin is associated with fast locomotion over short distances. This combination of characteristics allow these fish to live on the bottom of large South American rivers.

A new species of the Asian schilbid catfish genus Clupisoma from Myanmar, with a redescription of Clupisoma prateri Hora (Osteichthyes: Siluriformes: Schilbidae)

The species Clupisoma roosae, new species, is recorded from the upper Irrawaddy River, Myanmar. This species can be distinguished from its sole congener in Myanmar, Clupisoma prateri Hora, 1937, in having a shorter pectoral-fin spine that does not extend past the pelvic-fin origin, a reduced abdominal keel that extends anteriorly only to the level of the pelvic-fin base, only 11 pectoral-fin rays and 45 to 47 branched anal-fin rays. Although the two species occur in the Irrawaddy River, they have not been collected together and appear to inhabit different portions of the river basin. Clupisoma prateri is distributed in the lower and middle reaches of the Irrawaddy River as well as the nearby Sittang, Bago, and Salween rivers, while C. roosae appears to be restricted to the upper reaches of the Irrawaddy. To facilitate comparisons between the two species of Clupisoma in Myanmar, C. prateri is redescribed.