Pelvic Fin Rays Research Articles

Comparative Analysis of Fluctuating Asymmetry between Ploidy and Sex in Marine Medaka, Oryzias dancena.

The purpose of this study is to examine fluctuating asymmetry of eye diameter, maxilla length, operculum length, and the number of pectoral fin ray and pelvic fin ray between ploidy and sex in diploid and triploid marine medaka, Oryzias dancena. In all experimental groups, eye diameter and maxilla length showed no significant difference between left side and right side (p>0.05). Results of operculum length in triploid male group and pectoral fin ray's number in diploid male group showed similarity ones with results of operculum length in triploid female group and pectoral fin ray's number in diploid female group (p<0.05). However, the operculum length in diploid male group and pectoral fin ray's number in triploid male group showed consinderable difference with those of operculum length in diploid female group and pectoral fin in triploid female group. Findings of pelvic fin ray's number in all groups were similar to those of pectoral fin ray's number in all groups (p<0.01).

Precision of Calcified Structures Used for Estimating Age of Chain Pickerel

AbstractWith the exception of Northern Pike Esox lucius, there is a paucity of information on the precision of age estimates based on calcified structures for esocid species, especially Chain Pickerel E. niger. We estimated ages for 42 Chain Pickerel from Stevens Creek Reservoir on the Savannah River, South Carolina–Georgia. Ages were estimated using sectioned pelvic, pectoral, dorsal, and anal fin rays, scales, cleithra (sectioned and whole), and otoliths to assess precision between repeated readings (four readers). Precision was evaluated by calculating agreement among readers, CV, and mean absolute difference (MAD) in estimates between reader pairs. We tested for differences in precision of estimates among structures using linear mixed models with CV or MAD as the response. Finally, we used age bias plots to evaluate whether there were structure or reader‐related systematic biases in estimates. Coefficient of variation and MAD were significantly related to structure type (CV: P = 0.006, MAD: P = 0.001) and mean estimated age (CV: P &lt; 0.001, MAD: P = 0.025). Precision was poor for all structures and poorest for age‐0 fish; however, all analyses indicated that otoliths provided the most precise estimates. We observed agreement in estimates among all readers for 40% of the otoliths examined and consensus agreement for 74% of the estimates. Coefficient of variation for otoliths declined from 67% for fish with a mean estimated age of 0 years to 5% for age‐4 fish. Conversely, MAD for otoliths increased from 0.34 years for fish with a mean estimated age of 0 to 0.46 years for age‐4 fish. Estimates from all structures, except pectoral rays, were negatively biased compared with estimates from otoliths. We recommend the use of otoliths for age estimation of Chain Pickerel, but managers and researchers should be cognizant of and evaluate the potential effects of variability in age estimates among readers on their analyses.

Two new species of blue-eyed Trimma (Pisces; Gobiidae) from New Guinea.

Two new species of Trimma are described from New Guinea, one at the southeastern end at Normanby Island (Milne Bay Province), the other from Cendrawasih Bay, West Papua, on the north-east coast. The dorsal surface of the eye of both species is blue in life, a characteristic not reported elsewhere in the genus. Although the two species look very similar in life, and both occupy similar mesophotic rubble habitats in the 50-70 m depth range, they are separated both genetically (7.7% pairwise genetic distance in COI) and morphologically. Trimma blematium has 16 pectoral fin rays, a branched 5th pelvic fin ray, and 7 papillae in row p, whereas T. meityae has 17-18 pectoral fin rays, an unbranched 5th pelvic fin ray, and 8 papillae in row p. In live specimens, the blue colour over the top of the eyes is much darker in T. blematium than in T. meityae. The type localities are separated by almost 2,000 km (straight-line distance).

Robust and local positional information within a fin ray directs fin length during zebrafish regeneration.

It has been proposed that cells are regulated to form specific morphologies and sizes according to positional information. However, the entity and nature of positional information have not been fully understood yet. The zebrafish caudal fin has a characteristic V-shape; dorsal and ventral fin rays are longer than the central ones. This fin shape regenerates irrespective of the sites or shape of fin amputation. It is thought that reformation of tissue occurs according to positional information. In this study, we developed a novel transplantation procedure for grafting a whole fin ray to an ectopic position and examined whether the information that specifies fin length exists within each fin ray. Intriguingly, when long and short fin rays were swapped, they regenerated to form longer or shorter fin rays than the adjacent host fin rays, respectively. Further, the abnormal fin ray lengths were maintained for a long time, more than 5months, and after further re-amputation. In contrast to intra-fin grafting, when fin ray grafting was performed between fish, cells in the grafts disappeared due to immune rejection, and the grafted fin rays adapted to the host position to form a normal fin. Together, our data suggest that the information that directs fin length does exist in cells within a single fin ray and that it has a robust property-it is stable for a long time and is hard to rewrite. Our study highlighted a novel positional information mechanism for directing regenerating fin length.

Variation in flexural stiffness of the lepidotrichia within and among the soft fins of yellow perch under different preservation techniques.

Although the ray-finned fishes are named for their bony, segmented lepidotrichia (fin rays), we are only beginning to understand the morphological and functional diversity of this key vertebrate structure. Fin rays support the fin web, and their material properties help define the function of the entire fin. Many earlier studies of fin ray morphology and function have focused on isolated rays, or on rays from only one or two fins. At the same time, relatively little is known about how different preservation techniques affect the material properties of many vertebrate structures, including fin rays. Here, we use three-point bending tests to examine intra- and inter-fin variation in the flexural stiffness of fin rays from yellow perch, Perca flavescens. We sampled fin rays from individuals that were assigned to one of three preservation treatments: fresh, frozen, and preserved with formalin. The flexural stiffness of the fin rays varied within and among fins. Pelvic-fin rays were the stiffest, and pectoral fin rays the least stiff. The fin rays of the dorsal, anal, and caudal fins all had similar stiffness values, which were intermediate relative to those from the paired fins. The flexural stiffness of the fin rays was higher in rays that were at the leading edge of the fin. This variation in flexural stiffness was associated with variation in joint density and the relative length of the unsegmented proximal base of the fin rays. There was no significant difference in flexural stiffness between fresh and frozen specimens. In specimens preserved with formalin, there is a small but significant effect on stiffness in smaller fin rays.

The morphological diversity of Garra barreimiae [Teleostei: Cyprinidae

Garra barreimiae (Fowler and Steinitz, Bull Res Counc Isr 5B:262–289, 1956) is a freshwater fish that lives throughout the Hajar Mountains of Oman and the United Arab Emirates. Previously, four different genetic clades (West clade, Central Clade, North clade and East clade) have been identified within this species. This study observes morphological differences between these clades using morphometrics and meristics as well as micro CT imaging, further strengthening the assumption that the taxon of G. barreimiae should be restricted to one of the genetic clades detected. Although many morphometric and meristic characteristics are highly variable within the clades, the West clade fits the original description of G. barreimiae and is distinguishable by its higher number of fifteen to seventeen gill rakers on the lower limb of the first gill arch (compared to the other clades with ten to fourteen gill rakers), its seven branched pelvic fin rays (in contrary to the other clades with eight branched pelvic fin rays) and its number of vertebrae, with typically nineteen precaudal and one intermediate vertebrae, compared to eighteen precaudal and two intermediate vertebrae in the Central and North clade and seventeen precaudal and two intermediate vertebrae in the East clade.

Stocks Discrimination in Lady Fish, Elops machnata (Forskal, 1775) from Southeast and Southwest Coast of India Based on Morphometric and Meristic Analysis

Morphometric and meristic analysis of ladyfish, Elops machnata, were used to discriminate stocks along the Southeast and Southwest coast estuaries of India. Morphometric and meristic analyses showed a similar pattern of differentiation between E. machnata stocks and revealed a clear discreteness of two groups, an East coast (Marakanam, Parangipettai and Muthupettai) population and a West coast (Cochin) population. Higher total length (TL) (28.00 ± 7.043 cm), fork length (FL) (89.27 ± 2.201% TL) and standard length (SL) (81.77 ± 2.582% TL) were recorded in Cochin population and they were significantly different from the other three populations. Meristic counts were relatively homogenous in all the studied populations. No significant variation was found in counts of dorsal fin ray (DFR), anal fin ray (AFR), pectoral fin ray (PFR) and pelvic fin ray (PLFR). The first and second components (PCA analysis) accounted for about 92.2% of variation in all the morphometric characters. Among them, pre pectoral length (PPL) and pre dorsal length (PDL) showed high loading values in PC1 in all four populations. The overall random assignment of individuals to their original group was higher in morphometric than in meristic analysis. Such a presumption could be authenticated henceforth with molecular markers. Hence, further studies, using molecular markers are still required to precisely evaluate the genetic structure of E. machnata along the Indian coast.

New remarkable sexually dimorphic miniature species of Hyphessobrycon (Characiformes: Characidae) from the upper Rio Tapajós basin.

A new miniature species of Hyphessobrycon is described from an affluent of the Rio Papagaio, tributary of the Rio Juruena, upper Rio Tapajós basin, Mato Grosso State, Brazil. The new species can be distinguished from its congeners by having a remarkable secondary sexual dimorphism in its live colouration (males are red and females yellow), well-defined and relatively narrow dark midlateral stripe extending from tip of snout to tip of middle caudal-fin rays, absence of humeral blotch, 15-18 branched anal-fin rays and five or six branched pelvic-fin rays. The sexually dimorphic colouration of the new species is briefly discussed regarding its temporal variation.

A new deepwater assfish, Bassozetus nielseni sp. nov. (Ophidiiformes: Ophidiidae), from the North Atlantic and West Indian oceans

A new deepwater assfish, Bassozetus nielseni sp. nov., is described from 29 specimens [147–615 mm in standard length (SL)] collected from the North Atlantic and West Indian oceans. It is distinguished from 13 congeners by the following combination of characters: dorsal-fin rays 122–129, long rakers on first gill arch 11–14, oblique scales 20–25, abdominal vertebrae 13–14, head length 18.1–21.3 % SL, body depth at anal-fin origin 8.2–14.6 % SL, predorsal length 16.4–20.1 % SL, tail length 62.7–68.0 % SL, posterior tip of pelvic-fin rays anterior to anus, a single median basibranchial tooth patch, dorsal margin of sagittal otolith smooth, and fins pale yellowish brown (preserved condition).

A new species of Homatula from the Red River drainage in Yunnan based on morphological and genetic data (Teleostei: Nemacheilidae).

Homatula coccinocola, new species, is described from a Red River affluent in Honghe Prefecture, Yunnan, China. The combination of a fully scaled body, a notched lower jaw, 4+42-44 vertebrae, 11 pectoral-fin and 8 pelvic-fin rays, and a color pattern of 16-19 brown, somewhat straight and vertically solid bars on a beige background distinguishes the new species from its congeners. The generic diagnosis of Homatula is revised.

A new species of Trimma (Pisces; Gobiidae) from the South-West Islands of Palau, western Pacific Ocean

A new species of Trimma is described from South-West Islands of Palau. Trimma hamartium n. sp. lacks scales on the cheeks and opercle, has 8-9 scales in the predorsal midline, 17-19 pectoral-fin rays with 5-10 branched rays in the middle of the fin, an unbranched 5th pelvic-fin ray that is 51-64% the length of the 4th ray, 17-19 gill rakers on the outer surface of the first gill arch, an U-shaped interorbital trench with a narrow, slit-like postorbital trench ending at the last papilla in row p, and has 6 papillae in row c beneath the eye. When freshly collected, the species is very similar in appearance to T. preclarum, with which it is syntopic at three of the more northern islands of the South-West Islands.

Description and DNA barcoding of Lycenchelys lenzeni, a new species of eelpout (Perciformes: Zoarcidae) from the deep sea off the Kuril Archipelago.

A new species of eelpout genus Lycenchelys Gill, 1884 is described based on seven specimens caught at a depth of about 2350 m in the Bussol Strait, southwest of the Kuril Island Simushir. The species differs from its congeners in the following combination of characters: vertebrae 26-28 + 100-102 = 126-130; interorbital and occipital pores absent; postorbital pores 3-4; suborbital pores 7 (rarely 6); preoperculomandibular pores 4 + 4; gill rakers 11-16; dorsal fin rays 118-122; anal fin rays 105-108; pelvic fin rays 2; middle and lower ray tips of pectoral fin very slightly exserted; lateral line double with mediolateral and ventral branches; pyloric caeca not developed. The new species is morphologically most similar to Lycenchelys micropora and Lycenchelys jordani, which differ from the new species in having three pelvic-fin rays (vs. two pelvic-fin rays in the new species). L. micropora has the pectoral-fin origin below body midline, whereas the new species has the pectoral-fin origin at body midline. Middle and lower ray tips of pectoral fin are very slightly exserted in L. lenzeni sp. nov., whereas they are well exserted in L. jordani and L. micropora. Mitochondrial COI sequences were analyzed from four paratype specimens and all show the same haplotype sequence. The DNA barcodes allowed discrimination of L. lenzeni sp. nov. from other species of Lycenchelys where sequence data were available. The nearest match with already published sequences was Lycenchelys antarctica, with a sequence similarity of 98.25%, followed by Lycenchelys aratrirostris (sequence similarities 97.95-97.96%) and L. jordani (sequence similarity of 97.81%).

The “Lembeh Frogfish” Identified: Redescription of Nudiantennarius subteres (Smith and Radcliffe, in ) (Teleostei: Lophiiformes: Antennariidae)

The “Lembeh Frogfish” or “Ocellated Frogfish,” a distinct antennariid, known for many years, especially among members of the dive community, and suggested by some to represent an undescribed species, is identified as Nudiantennarius subteres (Smith and Radcliffe). Unique in several ways—including reduced dermal spinules, the body appearing naked; illicium short, about half the length of the second dorsal-fin spine; second dorsal-fin spine unusually long and narrow, without a posterior membrane; pectoral lobe narrow, somewhat detached from the body; membranes between the rays of the paired fins deeply incised; and all pelvic-fin rays simple—the species is redescribed and figured below. Morphological and molecular analyses indicate a close relationship with the Sargassumfish, Histrio histrio.

Review of Schismatogobius (Gobiidae) from Japan, with the description of a new species

Three species of Schismatogobius de Beaufort 1912, distinguished by their morphology and mitochondrial DNA sequences, were found in freshwater streams in the Ryukyu Archipelago, Japan. Although two species were previously known from Japan (S. roxasi Herre 1936 and S. ampluvinculus Chen, Shao, and Fang 1995), the taxonomy needs to be revised. To identify these species, the holotype morphology of S. marmoratus (Peters 1868), S. bruynisi de Beaufort 1912, and S. roxasi, originally described from the Philippines and Indonesia, were examined and re-described here, because relatively little information about their diagnostic characters was provided in the original descriptions. The three Japanese species were identified as S. ampluvinculus, S. marmoratus, and a new species. They were distinguished from each other and from their congeners by the banding pattern of the body, markings on the pectoral fins, pigment patterns on the ventral surface of the head and pelvic fin, body depth at the pelvic-fin origin, pre-anal length, and pectoral-fin ray counts. Although the new species had been regarded as S. roxasi in previous publications, we show that it is actually not S. roxasi and that it also differs from all other nominal species of Schismatogobius. This is described as a new species, S. ninja. Additionally, this is the first record of S. marmoratus from Japan.

A new Schistura from the Pearl River in Guangxi, China (Teleostei: Nemacheilidae).

Schistura paraxena, new species, is described from the Pearl River drainage in Laibin, Guangxi Province, China. The new species is easily distinguished from its congeners in having conspicuous peduncular crests along its dorsal and ventral extremities and a plain beige body coloration with crests brownish gray and a pale spot medially at caudal-fin base. Further characters useful to diagnose the species, but not unique to it, are: 8½ branched dorsal-fin rays; 11-12 pectoral-fin and 9 pelvic-fin rays; modally 38 vertebrae; predorsal length 50-52% SL; caudal-peduncle length 17-18% SL (88-92% HL; 5.6-5.8 times SL); lateral line complete; breast naked; predorsal area scaled; and upper lip not notched.

Hypostomus sertanejo (Siluriformes: Loricariidae), new armoured catfish species from north-eastern Brazil.

A re-evaluation of the armoured catfish species of Hypostomus in the Rio Jaguaribe, north-eastern Brazil, was prompted by the discovery of specimens with pale spots on a dark background collected from that basin c. 1936 and deposited at the Academy of Natural Sciences of Philadelphia. Recent field collections in the Rio Jarguaribe basin confirmed the presence of the pale-spotted specimens and its distinctiveness as a new species. Hypostomus sertanejo n. sp. is diagnosed from other species of Hypostomus by having fins and dermal-plated regions of head and body with pale spots or vermiculations on darker background, teeth slender, asymmetrically bicuspid and numerous (34-75) on dentary and premaxilla, depressed dorsal-fin spine not reaching adipose spine, unbranched pectoral-fin spine longer than unbranched pelvic-fin ray, seven branched dorsal-fin rays and one (rarely two) predorsal plate(s) bordering supraoccipital. Ancistrus salgadae Fowler 1941 is hypothesized to be a junior synonym of Hypostomus carvalhoi (Miranda-Ribeiro, 1937), a dark-spotted Hypostomus described from the Rio Granjeiro, a tributary to the upper Rio Salgado.

Comparison of the Precision of Age Estimates Generated from Fin Rays, Scales, and Otoliths of Blue Sucker

Abstract Evaluating the precision of age estimates generated by different readers and different calcified structures is an important part of generating reliable estimations of growth, recruitment, and mortality for fish populations. Understanding the potential loss of precision associated with using structures harvested without sacrificing individuals, such as scales or fin rays, is particularly important when working with imperiled species, such as Cycleptus elongatus (Blue Sucker). We collected otoliths (lapilli), scales, and the first fin rays of the dorsal, anal, pelvic, and pectoral fins of 9 Blue Suckers. We generated age estimates from each structure by both experienced (n = 5) and novice (n = 4) readers. We found that, independent of the structure used to generate the age estimates, the mean coefficient of variation (CV) of experienced readers was approximately 29% lower than that of novice readers. Further, the mean CV of age estimates generated from pectoral-fin rays, pelvic-fin rays, and scales...

Two new species of Trimma (Pisces; Gobiidae) from Fiji, south-western Pacific Ocean.

Two new species of Trimma are described from Fiji. Trimma bathum n. sp. lacks scales on the cheeks, opercle and predorsal midline, has 18-19 unbranched pectoral fin rays, an unbranched 5th pelvic fin ray that is 40-56% the length of the 4th ray, 17-18 gill rakers on the outer surface of the first gill arch, a U-shaped interorbital and a narrow slit-like postorbital trench, a low, median fleshy ridge extending half-way towards the orbit from the origin of the first dorsal fin, and, when freshly collected, a pink head and body with most body scales having an orange-brown spot or short bar at their centres. The species is currently known only from off Suva Harbour, Viti Levu, Fiji. Trimma finistrinum n. sp. has a bony interorbital equal to the pupil diameter, a fully scaled nape of 12-14 scales, a second dorsal spine that may reach posteriorly to the middle of the second dorsal fin, the papillae in the longitudinal row immediately below the eye either single or with two papillae in a vertical row, unbranched pectoral fin rays, usually a branched fifth pelvic-fin ray that is about half length of the fourth ray, and a large diffuse dark blotch on the posterior part of the caudal peduncle. A colour pattern of a brownish body with most body scales having golden- to greenish-yellow (pale in preservative) centres is unique among species of the genus. The species is currently recorded only from off the north and east coasts of Viti Levu, Fiji.

Meristic character variability among populations of Silurus triostegus Heckel, 1843 from the Euphrates, Tigris, and Shatt al-Arab Rivers, Iraq

AbstractVariation in the numbers of pectoral fin spines and rays, pelvic fin rays, gill rakers on the first gill arch, anal fin rays, and the number of vertebrae of Silurus triostegus Heckel were examined in specimens from 16 localities that span its entire distribution range in the Tigris, Euphrates, and Shatt al-Arab rivers in Iraq. The mean number of the six meristic traits increases toward high latitudes with maximum and minimum values in the north and south of Iraq. Based on cluster analysis and PCA, the Mesopotamian river samples were clearly separated into three distinct groups. The upper Tigris populations were isolated from those of the middle and southern populations of this river and from those of the Euphrates River. Possible reasons for such differentiation among populations are discussed, and the integration of research on this species among the countries neighboring Iraq is required.

The first record of a frogfish, Fowlerichthys scriptissimus (Antennariidae, Lophiiformes), from Korea

This is the first report of Fowlerichthys scriptissimus (Lophiiformes, Antennariidae) from Korea. A single specimen (291.0 mm SL) was collected off the coast of Jejudo Island by gill net on 28 March 2012 and identified with morphological and molecular approaches. The specimen is characterized by having all five pelvic fin rays bifurcate and possessing 20 vertebrae, 13 pectoral-fin rays, and a basidorsal ocellus on the side of the body. This species is distinguishable from other Korean taxa by the number of pectoral fin rays, the bifurcate form of the pelvic rays, and the vertebral count. We add this species to the Korean fish fauna and suggest new Korean names, “Byeol-ssin-beng-i-sok” and “Byeol-ssin-beng-i” for the genus and species, respectively.