Lateral Scales Research Articles

Balitora chipkali, a new species of stone loach (Teleostei: Balitoridae) from the northern Western Ghats of India, with a note on the distribution of B. laticauda.

Balitora chipkali, a new species of stone loach, is described from the westward-flowing Astoli tributary of the Kali River system in the northern part of the Western Ghats, India. The species differs from its congeners in a combination of characters that includes: a single pair of maxillary barbels; a large eye, of diameter greater than 15% head length (HL); snout length less than 4 times eye diameter; gape of mouth less than 30% HL; upper lip with 9-12 papillae in first series and 3-8 papillae in second series; flattened body, of depth less than 15% standard length; caudal-peduncle length less than three times its depth, 66-68 lateral line scales, 11 caudal vertebrae excluding compound centrum, third infraorbital sensory canal tube straight; and a distinct color pattern with almost round 7 dorsal saddles not reaching lateral irregular crossbar markings. Balitora chipkali forms a monophyletic group with B. laticauda as its sister taxon in a phylogeny based on a concatenated cytochrome b (Cytb) and cytochrome oxidase subunit 1 (COI) gene fragments. Raw genetic distance between B. chipkali and B. laticauda was 1.9-2.2% based on COI and 3.4-4.3% based on Cytb partial gene sequences, which was far more than the intra-species variation in widely separated populations of B. laticauda. Based on molecular and morphological analysis, we also provide new locality records for B. laticauda and delimit its distribution to eastward-flowing tributaries of the Krishna River system in the northern Western Ghats.

Multi-sensor in situ observations to resolve the sub-mesoscale features in the stratified Gulf of Finland, Baltic Sea

Abstract. High-resolution numerical modeling, remote sensing, and in situ data have revealed significant role of sub-mesoscale features in shaping the distribution pattern of tracers in the ocean's upper layer. However, in situ measurements are difficult to conduct with the required resolution and coverage in time and space to resolve the sub-mesoscale, especially in such relatively shallow basins as the Gulf of Finland, where the typical baroclinic Rossby radius is 2–5 km. To map the multi-scale spatiotemporal variability in the gulf, we initiated continuous measurements with autonomous devices, including a moored profiler and Ferrybox system, which were complemented by dedicated research-vessel-based surveys. The analysis of collected high-resolution data in the summers of 2009–2012 revealed pronounced variability at the sub-mesoscale in the presence of mesoscale upwelling/downwelling, fronts, and eddies. The horizontal wavenumber spectra of temperature variance in the surface layer had slopes close to −2 between the lateral scales from 10 to 0.5 km. Similar tendency towards the −2 slopes of horizontal wavenumber spectra of temperature variance was found in the seasonal thermocline between the lateral scales from 10 to 1 km. It suggests that the ageostrophic sub-mesoscale processes could contribute considerably to the energy cascade in such a stratified sea basin. We showed that the intrusions of water with different salinity, which indicate the occurrence of a layered flow structure, could appear in the process of upwelling/downwelling development and relaxation in response to variable wind forcing. We suggest that the sub-mesoscale processes play a major role in feeding surface blooms in the conditions of coupled coastal upwelling and downwelling events in the Gulf of Finland.

Morphometric and meristic characterization of the endemic Desert chub Gila eremica (Teleostei: Cyprinidae), and its related congeners in Sonora, Mexico

The Desert chub, Gila eremica DeMarais, 1991 is a freshwater fish endemic to Northwest Mexico, being described from the Sonora, Matape and Yaqui River basins in Sonora, Mexico. The recent discovery of 2 isolated small populations from the known distribution for this taxon makes necessary an evaluation to determine their specific taxonomical identities (herein designated as G. cf. eremica). Thirty-three morphometric and 6 meristic characters were evaluated in 219 specimens of several populations of the genus Gila in Sonora, including all the known populations of G. eremica. Morphometric measures based on box-truss protocol were standardized by regression models, and analyzed by means of a discriminant function analysis (DFA). The canonical variables 1 and 2 explained 72.4% of the total variation among analyzed populations. Tree diagram based on squared Mahalanobis distances, as well as scatterplots of centroids, showed G. cf. eremica to be morphologically divergent with respect to known populations of G. eremica as well as the other species analyzed. Box plots indicated a slimmer body and a smaller number of pectoral fin rays, and a higher number of lateral line scales as the most distinguishable characters in G. cf. eremica with respect to nominal G. eremica.

Primer registro de anidamiento de la tortuga marina Chelonia agassizi en Punta Ratón, Honduras

The Presence of Chelonia agassizi is confirmed in the Golfo de Fonseca, Honduras. A single female was observed laying 67 eggs in Punta Raton. The mean of meristic counts of four neonates after 47 days of natural incubation are: carapace length 44.9 mm., carapace width 35.7 mm., plastron length 35.9 mm., head width 14.3 mm., vertebral scales 5.7 , lateral scales 4-4 .2, marginal scales 11.7-12, nucal scale 2, postorbital scales 3.2-3.5.

A new species of Moenkhausia Eigenmann, 1903 (Characiformes, Characidae) from the rio Amazonas basin, Brazil.

Moenkhausia abyss is herein described from the rio Amazonas basin lowlands. The new species can be distinguished from the congeners by presenting the combination of the following characters: a dark blotch located on the upper caudal-fin lobe and the lower lobe hyaline, 25-29 branched anal-fin rays, humeral spot rectangular, vertically oriented, extending horizontally through two or two and a half scales and located over the third to the fifth lateral line scales, five longitudinal scale rows above the lateral line, predorsal scales arranged in a single not interrupted median row and 30-34 perforated lateral line scales. Brief comments on Moenkhausia megalops are provided.

MEGANTHIAS KINGYO (KON, YOSHINO AND SAKURAI, 2000) (PERCIFORMES: SERRANIDAE) FROM BITUNG, NORTH SULAWESI, INDONESIA: FIRST RECORD FROM THE SOUTHWESTERN PACIFIC OCEAN

Eight specimens of Meganthias kingyo were collected from Bitung, North Sulawesi, Indonesia between 2008 - 2010. The specimens were caught from about 70-150 m off Lembeh Island. M. kingyo differs from M. natalensis by having the following characteristics: pores lateral line scales (43 vs. 49); pectoral rays (16 vs. ii.14); body depth (47.1 vs. 51.9); head length (31.0 vs. 38.2), body depth (47.1 vs. 52.9), caudal peduncle depth (12.1 vs. 14.2), pectoral fin length (28.0 vs. 34.3), pelvic fin length (33.6 vs. 31.1), anal fin base length (19.4 vs. 22.2), caudal fin length (66.9 vs. 35.3) and longest dorsal fin ray (48.5 vs. 27.4). Previously, this species has been reported from Houzan-sone, off Miyako and Yaeyama Islands in Okinawa, Japan; and herein is recorded from off Lembeh Island, North Sulawesi, Indonesia.

High-resolution stratigraphy and facies architecture of the Upper Cretaceous (Cenomanian–Turonian) Eagle Ford Group, Central Texas

Rock-based studies of the Eagle Ford Group of Central Texas demonstrate that mudrock deposition is more complicated than previously supposed. X-ray diffraction, x-ray fluorescence, total organic carbon (TOC), and log data collected from eight cores and two outcrops demonstrate that bottom-current reworking and planktonic productivity are primary depositional controls, acting independently from eustatic forcing. Central Texas Eagle Ford facies include (1) massive argillaceous mudrock, (2) massive foraminiferal calcareous mudrock, (3) laminated calcareous foraminiferal lime mudstone, (4) laminated foraminiferal wackestone, (5) cross-laminated foraminiferal packstone–grainstone, (6) massive bentonitic claystone, and (7) nodular foraminiferal packstone–grainstone. High degrees of lateral facies variability, characterized by pinching and swelling of units, lateral facies changes, truncations, and locally restricted units, are observed even at small lateral scales (50 ft [15 m]). At 10 mi (16 km) and greater lateral spacings, core and geochemical data significantly underestimate intraformational facies variability. Approximately 73% of units can be successfully correlated across a distance of 500 ft (152 m), 35% are traceable across 1 mi (1.6 km), and only 16% of beds are correlative across 10 mi (16 km). Geochemical proxies (enrichment in molybdenum and other trace elements) indicate that maximum anoxia occurred within the Bouldin Member despite being composed of the most calcareous and high-energy facies. Comparison of total gamma ray (GR) logs to computed GR logs is requisite, because GR alone may provide misleading determination of facies, TOC content, depositional environment, and sequence stratigraphic implications.

Phase-induced amplitude apodization complex mask coronagraph mask fabrication, characterization, and modeling for WFIRST-AFTA

This work describes the fabrication, characterization, and modeling of a second-generation occulting mask for a phase-induced amplitude apodization complex mask coronagraph, designed for use on the WFIRST-AFTA mission. The mask has many small features (∼micron lateral scales) and was fabricated at the Jet Propulsion Laboratory Microdevices Laboratory, then characterized using a scanning electron microscope, atomic force microscope, and optical interferometric microscope. The measured fabrication errors were then fed to a wavefront control model which predicts the contrast performance of a full coronagraph. The expected coronagraphic performance using this mask is consistent with observing ∼15 planetary targets with WFIRST-AFTA in a reasonable time (<1 day/target).

Scale morphology and specialized dorsal scales of a new teleosteomorph fish from the Aptian of West Gondwana

Abstract. Scales of a new species of Teleosteomorpha from the continental Aptian of the south of South America are studied. These neopterygians are from the La Cantera Formation in central Argentina, and were previously identified as Pholidophoriformes. They present ganoid scales; most of them are rhombic with well-developed peg-and-socket articulations and possessing a smooth surface. They have a straight posterior margin, but occasionally, some scales of the flank have a sinuous posterior margin with one or two serrations. The shape of the scales varies along the body from large, rectangular and deeper than long scales behind the head to the preanal region to smaller and rhomboidal scales in the caudal region. There are a few horizontal rows along the flank and about 32 lateral line scales. Thick, round ganoid scales are present in the prepelvic region close to the ventral margin. The round and rhombic scales present growth lines, which form concentric ridges on the external side. A characteristic row of deep scales forms the dorsal margin on each side of the body; a row of median ridge scales is not present. This is a unique feature of the studied fishes. Scutes covered with unornamented ganoine precede the pelvic, dorsal, and anal fins, as well as the dorsal and ventral margins of the caudal fin. The posterior margin of the dorsal lobe of the caudal fin is formed by a single line of scales, which continues and covers the base of the first principal caudal ray. Histological studies reveal a lepisosteoid-scale type with multiple ganoine layers, lack of dentine, and the presence of canaliculi of Williamson. The macro- and micromorphology of the scales shows features that are found in other teleosteomorphs, but also in other neopterygians.

A new Silver Dollar species of Metynnis Cope, 1878 (Characiformes: Serrasalmidae) from Northwestern Brazil and Southern Venezuela

ABSTRACT A new Metynnis is described from the rio Negro in Brazil and Venezuela, and from black- or clearwater tributaries in Brazil including the rios Parauari, Uatumã, Trombetas, and Sucunduri (the latter belonging to the rio Madeira basin). The new species can be distinguished readily from all congeners by having a high concentration of dark chromatophores on the lateral line scales. It can be further distinguished by the combination of head length 24.3-27.5% of SL, 13-18 gill-rakers on upper limb and 16-24 gill-rakers on lower limb. The new species is most similar to and likely most closely related to Metynnis hypsauchen . These two species share a similar color pattern, body shape and sexual dimorphism of the anal fin. However, they differ in that M. hypsauchen has a lightly pigmented lateral line. The new species is also distinguished from M. hypsauchen by having 56-65 predorsal scales and 90-104 lateral line scales (vs . 36-54, and 65-82, respectively). A detailed osteological description of the new species is provided.

A new species of Bryconops (Ostariophysi: Characiformes: Characidae) from the upper rio Tocantins drainage, Brazil

ABSTRACT A new species of the genus Bryconops , subgenus Bryconops , is described from the rio Conceição, a tributary to the rio Palma, upper rio Tocantins drainage, Tocantins State, Brazil. The new species is distinguished from all its congeners, except B. humeralis and B. vibex by the color pattern in vivo (dorsal, adipose, and caudal fins entirely orange). The new species is easily distinguished from B. humeralis and B. vibex by the absence of a humeral spot and by the lack of maxillary teeth (vs . presence of a single humeral spot and presence of 1-3 maxillary teeth on both sides). Furthermore, the new species is distinguished from B. vibex by the number of perforated lateral line scales (38-41 vs. 44-46).

The Interplay Between Submesoscale Instabilities and Turbulence in the Surface Layer of the Bay of Bengal

The Air-Sea Interactions Regional Initiative (ASIRI) aims to understand vertical fluxes of momentum and heat across the surface layer in the Bay of Bengal. As the mesoscale and submesoscale eddies redistribute freshwater input over saline water of the bay, they influence the vertical distribution of salinity and thus impact air-sea fluxes. This study reports on numerical simulations performed to investigate processes that can lead to the observed vertical structure of stratification near the ocean surface. Processes are explored at multiple lateral scales, ranging from a few meters to tens of kilometers, to elucidate how the interplay among large-scale motion, submesoscale instabilities, and small-scale turbulent motion affects the surface layer.

Experimental evaluation of calcein and alizarin red S for immersion marking of silver carpHypophthalmichthys molitrix(Valenciennes, 1844)

Summary Calcein (CAL) and alizarin red S (ARS) at concentrations of 50–200 and 150–300 mg/L, respectively, were used for immersion marking of juvenile silver carp Hypophthalmichthys molitrix (79.65 ± 2.11 mm total length, mean ± SD). The marked fish were kept in separate tanks (0.012 individuals per litre, rearing temperature 18.4–25.7°C) for 360 days. Each experimental treatment group consisted of three replicates (16 individuals per replicate). Immersion for 24 h produced detectable marks in the sagittae, lateral line and non-lateral line scales, and fin rays (dorsal, pectoral, ventral, anal, and caudal) at 360 days post-marking. Acceptable marks in the sagittae were observed for CAL at concentrations of 150–200 mg/L and for ARS at concentrations of 200–300 mg/L. Fluorescent marks were poorly visible in all non-lateral line scales from both the CAL- and ARS-treated groups. Acceptable fluorescent marks in the lateral line scales and fin rays were detected for CAL at concentrations of 150–200 and 100–200 mg/L, respectively, and for ARS at concentrations of 200–300 and 150–300 mg/L, respectively. In particular, optimal marks were observed at the highest concentrations investigated in lateral line scales (200 mg/L CAL, 300 mg/L ARS) and fin rays (200 mg/L CAL, 200–300 mg/L ARS). There was no significant difference in the survival or growth of marked fish compared to controls throughout the experiment (P > 0.05).

The evolution and state of interdisciplinary hyporheic research

Hyporheic zones are of broad interest, given their location at the interface between surface and groundwaters, numerous ecological functions, and location as a zone of interdependent physical, chemical, and biological processes. Hyporheic research has been successful in study of individual processes, but our understanding of coupled, interacting processes in hyporheic zones remains limited. Based on an analysis of publications and citations, interest in the hyporhec zone was catalyzed by ecological functions, and interest has become more balanced across disciplines and functions in recent years. Analysis of publications and field studies spanning 12 identified hyporheic processes demonstrates that studies commonly focus on 1–3 processes limiting our ability to characterize interaction or interdependence of hyporheic processes. Analysis of field studies demonstrate that the most frequently studies scales are second‐ and third‐order streams with longitudinal, lateral, and vertical scales of 10–1000+ m, 1–10, and 0–1 m, respectively. These studies commonly considered variations spanning timescales of storm events to seasons. I identified a total of 86 variables used to characterize hyporheic processes of which the most frequently reported 14 variables represent more than 50% of all variables found in this analysis. Thus, a relatively small suite of variables may hold key information to enable cross‐site comparison of findings. Future hyporheic research should address the challenges of (1) defining common metadata to support interdisciplinary research and cross‐site comparison and (2) quantifying spatial and temporal heterogeneity in hyporheic functions to enable multi‐scale assessment and prediction of hyporheic processes.WIREs Water2016, 3:83–103. doi: 10.1002/wat2.1120This article is categorized under:Science of Water &gt; Methods

Baltic Sea Gastrotricha—one new species and one new record of Chaetonotida from Poland

Gastrotricha is a cosmopolitan phylum of aquatic and semi-aquatic invertebrates that comprise about 820 described species, which are divided into two orders: Chaetonotida Remane, 1925 [Rao & Clausen, 1970] and Macrodasyida Remane, 1925 [Rao & Clausen, 1970]. They inhabit natural as well as artificial habitats in diverse marine, freshwater, and semi-aquatic ecosystems (e.g. peatbogs, alder woods, riparian forests). Until now, 29 species of gastrotrichs from the Polish Baltic Sea region (including three freshwater species which were found in estuaries) were known. Sixteen species belong to Chaetonotida and thirteen to Macrodasyida. During this study we found two species, Heterolepidoderma sinus spec. nov., and Aspidiophorus lamellophorus Balsamo, Hummon, Todaro et Tongiorgi, 1997 which is new to the Baltic Sea fauna. H. sinus spec. nov. has distinct cuticular reinforcements in the anterior dilatation of the pharynx. Moreover, it is characterized by two kinds of lamellae: one type is represented by small triangular lamellae which aris from lateral scales, the second type is large and clearly visible and arises from ventral scales. None of the Heterolepidoderma species known so far has two types of lamellae. A. lamellophorus was previously known only from the Mediterranean Sea. The finding of two new gastrotrich species in the Baltic Sea shows that the knowledge of these small invertebrates in the area is still far from complete.

A New Barcheek Darter Species from Buck Creek (Cumberland River System), Kentucky (Percidae: Etheostomatinae:Catonotus:Oopareia)

Abstract Etheostoma nebra, the Buck Darter, is described as a new species endemic to the Buck Creek system of the Cumberland River drainage in Kentucky, USA. The earliest collection records of Etheostoma nebra date to 1955 and were considered a population of Etheostoma virgatum. Etheostoma nebra is delimited through morphological comparisons with Etheostoma virgatum and phylogenetic analyses using DNA sequences from a mitochondrial gene and five nuclear genes. Etheostoma nebra is distinguished from Etheostoma virgatum by a lower number of total lateral scales, fewer pored lateral scales and modally 13 compared with 12 pectoral fin rays. The two species also differ in patterns of pigmentation and nuptial male coloration. In the molecular phylogenies, Etheostoma nebra is not resolved as the sister species of Etheostoma virgatum. A review of all museum collection records of Etheostoma nebra and extensive field surveys in the Buck Creek system demonstrate a dramatic decline of the species over the past 30 yea...

New Record of Brama dussumieri (Pisces: Bramidae) from Korea, as Revealed by Morphological and Molecular Analyses

Ten specimens of Brama dussumieri (family Bramidae) were collected from waters off Jeju Island, Busan, and Gangneung, Korea, during 2013-2014. The specimens were characterized by having 58-64 lateral line scales and 13-15 gill rakers. An analysis of 567 base pair sequences of mitochondrial DNA cytochrome c oxidase subunit I showed that sequences in our ten specimens are concordant with those of B. dussumieri from the USA, India, and Japan, although with slight differences (genetic distance = 0.000-0.018). Brama dussumieri was distinguished from the most similar species, Brama japonica, by the number of lateral line scales (57-65 in B. dussumieri vs. 65-75 in B. japonica) and the number of gill rakers (13-15 in B. dussumieri vs. 17-20 in B. japonica). We propose the new Korean name "Wae-sae-da-rae" for B. dussumieri in Korea.

The Impact of Submesoscale Physics on Primary Productivity of Plankton

Life in the ocean relies on the photosynthetic production of phytoplankton, which is influenced by the availability of light and nutrients that are modulated by a host of physical processes. Submesoscale processes are particularly relevant to phytoplankton productivity because the timescales on which they act are similar to those of phytoplankton growth. Their dynamics are associated with strong vorticity and strain rates that occur on lateral scales of 0.1-10 km. They can support vertical velocities as large as 100 m d(-1) and play a crucial role in transporting nutrients into the sunlit ocean for phytoplankton production. In regimes with deep surface mixed layers, submesoscale instabilities can cause stratification within days, thereby increasing light exposure for phytoplankton trapped close to the surface. These instabilities help to create and maintain localized environments that favor the growth of phytoplankton, contribute to productivity, and cause enormous heterogeneity in the abundance of phytoplankton, which has implications for interactions within the ecosystem.

Crustal-scale shear zones and heterogeneous structure beneath the North Anatolian Fault Zone, Turkey, revealed by a high-density seismometer array

Continental scale deformation is often localised along strike-slip faults constituting considerable seismic hazard in many locations. Nonetheless, the depth extent and precise geometry of such faults, key factors in how strain is accumulated in the earthquake cycle and the assessment of seismic hazard, are poorly constrained in the mid to lower crust. Using a dense broadband network of 71 seismic stations with a nominal station spacing of 7 km in the vicinity of the 1999 Izmit earthquake we map previously unknown small-scale structure in the crust and upper mantle along this part of the North Anatolian Fault Zone (NAFZ). We show that lithological and structural variations exist in the upper, mid and lower crust on length scales of less than 10 km and less than 20 km in the upper mantle. The surface expression of the NAFZ in this region comprises two major branches; both are shown to continue at depth with differences in dip, depth extent and (possibly) width. We interpret a <10 km wide northern branch that passes downward into a shear zone that traverses the entire crust and penetrates the upper mantle to a depth of at least 50 km. The dip of this structure appears to decrease west–east from ∼90° to ∼65° to the north over a distance of 30 to 40 km. Deformation along the southern branch may be accommodated over a wider (>10 km) zone in the crust with a similar variation of dip but there is no clear evidence that this shear zone penetrates the Moho. Layers of anomalously low velocity in the mid crust (20–25 km depth) and high velocity in the lower crust (extending from depths of 28–30 km to the Moho) are best developed in the Armutlu–Almacik block between the two shear zones. A mafic lower crust, possibly resulting from ophiolitic obduction or magmatic intrusion, can best explain the coherent lower crustal structure of this block. Our images show that strain has developed in the lower crust beneath both northern and southern strands of the North Anatolian Fault. Our new high resolution images provide new insights into the structure and evolution of the NAFZ and show that a small and dense passive seismic network is able to image previously undetectable crust and upper mantle heterogeneity on lateral length scales of less than 10 km.

Mahseers genera Tor and Neolissochilus (Teleostei: Cyprinidae) from southern Vietnam.

Two new species and two new basin records of mahseers in the genera Tor and Neolissochilus are described from the upper Krong No and middle Đồng Nai drainages of the Langbiang Plateau in southern Vietnam. These new species and new records are known from streams and rivers in montane mixed pine and evergreen forests between 140 and 1112 m. Their populations are isolated in the Sre Pok River of the Mekong basin, the middle of the Đồng Nai basin, and the An Lão River. Both new species are differentiated from their congeners by a combination of the following characters: 23-24 lateral scales, 9-10 predorsal scales, 2/7 or 1/8 pelvic-fin rays, mouth position, median lobe of lower lip, rostral hood, colour in life and by divergent mitochondrial DNA. Tor mekongensis sp. nov. is differentiated from Tor dongnaiensis sp. nov. by the number of transverse scale rows (3/1/2 vs. 4/1/2), number of pelvic-fin rays (2/7 vs. 1/8), a blunt rostral hood vs. pointed, caudal-fin lobes that are equal vs. unequal, and by mitochondrial DNA (0.7% sequence divergence). Molecular evidence identifies both species as members of the genus Tor and distinct from all congeners sampled (uncorrected sequence divergences &gt;1.9% for all Tor species for which homologous COI sequences are available). Tor sinensis is recorded in the Krong No and the Sre Pok rivers, further south of its known distribution. Polymorphism is described in Neolissochilus stracheyi with a Tor-like morph and a Neolissochilus-like morph.