A New Species of Lanternfish (Osteichthyes, Myctophidae) from the South Atlantic

Lampichthys rutkovichi sp.n. is described from two stations over the Wal vis Ridge, southeast Atlantic Ocean. It differs from the only other species in this genus, L. procerus (Brauer, 1904), by the structure and size of its caudal luminous glands, the structure of the medial side of the otolith (sagitta), the proportion of otolith length to body length and the number of gill rakers on the first gill arch.     

Lanternfish (Myctophidae) Zoogeography off Eastern Australia: A Comparison with Physicochemical Biogeography

In this first attempt to model the distributions of a mesopelagic fish family at this scale in the eastern Australian region (10°S to 57°S), lanternfish species occurrence data spanning a period from 1928 to 2010 were modelled against environmental covariates. This involved: (1) data collation and taxonomic quality checking, (2) classification of trawls into “horizontal” (presence-absence) and “oblique” (presence-only) types, and classification of vertical migration patterns using existing literature and the species occurrence database, (3) binomial GAMs using presence-absence data for representative temperate, subtropical and tropical species to examine depth interactions with environmental covariates and refine the selection of environmental layers for presence-only MAXENT models, (4) Presence-only MAXENT modelling using data from all trawls and the reduced environmental layers, and (5) Multivariate analysis (area-wise and species-wise) of the resulting matrix of logistic score by geographic pixel. We test the hypothesis that major fronts in the region (Tasman Front, Subtropical Convergence, Subantarctic Front) represent zoogeographic boundaries. A four-region zoogeographic scheme is hypothesised: Coral Sea region, Subtropical Lower Water region, Subtropical Convergence/South Tasman region and Subantarctic region. The Tasman Front, Subtropical Convergence and Subantarctic Front represented zoogeographic boundaries. An additional boundary at ∼25°S (coined the ‘Capricorn’ boundary) was adopted to delineate the Coral Sea from Subtropical Lower Water regions. Lanternfish zoogeographic regions are congruent with some aspects of two prevailing physicochemical biogeographic schema in the region, but neither of these schema alone accurately predicts lanternfish distributions. As lanternfishes integrate vertical ocean processes, the hypothesised lanternfish zoogeography may represent a useful model for a generalised pelagic biogeography that should be tested for other oceanic groups.     

Lanternfish (Myctophidae) in the diet of the Cape petrel Daption capense at the South Shetland and South Orkney Islands, Antarctica

All of the fish identified in stomach contents and regurgitations of breeding and chick Cape petrels collected during January and February 1996 at Fildes Peninsula and Harmony Point, both in the South Shetland Islands and at Laurie Island, South Orkney Islands, were myctophids, a family never previously reported in the diet of breeding Cape petrels. Electrona antarctica was the most important fish prey, followed by Electrona carlsbergi at Fildes Peninsula, Krefftichthys anderssoni at Harmony Point and Gymnoscopelus braueri at Laurie Island. The absence of Pleuragramma antarcticum in the diet of this petrel, which is considered a P. antarcticum-feeder, is discussed. Received: 22 December 1997 / Accepted: 6 June 1998     

Genetic divergence in the tribe Electronini (Myctophidae)

To reveal evolutionary relationships and the rate of divergence of lanternfishes in the tribe Electronini (Myctophidae), analysis of sequence of cox 1 mtDNA fragment in three genera (12 species) of the tribe and in a closely related genus Myctophum (9 species) was performed. The results support the tribe monophyly; however, the divergence within it appeared to be not profound: genetic distances between genera and subgenera are smaller than between species within Myctophum and other genera of myctophids. In subgenera of Protomyctophum, species formation has obviously not completed since interspecies distances in them (0.5–4.7%) are comparable to estimates of intraspecific variation in other lanternfishes. Minimal genetic differences were found between species P. (Hierops) arcticum and P. (H.) subparallelum, whose ranges at the present time are isolated in the northern and southern hemispheres. After calibration of the molecular clock, the time of isolation of these two species can be dated to the Middle Pleistocene. Weak tribe diversification indicates its evolutionary youth, which can be related to the absence of efficient hydrographic barriers for isolation. The data obtained do not permit to consider tribe members as the most primitive in the family Myctophidae.     

The trophodynamics of Southern Ocean Electrona (Myctophidae) in the Scotia Sea

The Scotia Sea is one of the most productive regions of the Southern Ocean, but its surface waters are experiencing a rapid increase in temperature, which may be changing the behaviour and distribution of many myctophids and their prey species. Electrona antarctica and Electrona carlsbergi are two of the most abundant myctophids in the region, but their ecology is poorly understood and their response to ongoing environmental change is difficult to determine. This study investigated spatial and temporal patterns in their abundance, population structure and diets using mid-water trawl nets deployed across the Scotia Sea during spring, summer and autumn. E. antarctica was the most numerically abundant species (0.09–0.21 ind. 1,000 m^?3), with greatest concentrations occurring in the sea-ice sectors. E. carlsbergi occurred in more northern regions, comprising densities of 0.02–0.11 ind. 1,000 m^?3. There was evidence of seasonal variation in depth distribution, size-related sexual dimorphism and size-specific vertical stratification for both species. Latitudinal trends in sex ratio and female body size were apparent for E. antarctica. Its diet varied between regions, seasons and size classes, but overall, Euphausia superba, Metridia spp. and Themisto gaudichaudii were the dominant prey items. E. carlsbergi appeared not to recruit in the Scotia Sea. Its diet was dominated by copepods, particularly Rhincalanus gigas and Metridia spp., but regional, seasonal and ontogenetic variations were evident. This study contributes to our understanding of how mid-water food webs are structured in the Southern Ocean and their sensitivity to ongoing environmental change.     

Trophodynamics of Protomyctophum (Myctophidae) in the Scotia Sea (Southern Ocean)

This study investigated spatial and temporal patterns in distribution, population structure and diet of Bolin's lanternfish Protomyctophum bolini, Tenison's lanternfish Protomyctophum tenisoni and gaptooth lanternfish Protomyctophum choriodon in the Scotia Sea using data collected by midwater trawl during spring, summer and autumn. Protomyctophum bolini was the most abundant species of the genus encountered throughout the Scotia Sea with the greatest concentrations occurring around the Antarctic Polar Front (APF). This species had a life cycle of 2+ years, but spatial differences in population structure were apparent as the I‐group was absent from all regions south of the APF, suggesting that the species does not recruit in the Scotia Sea. Protomyctophum tenisoni occurred mostly in waters characteristic of the APF and was absent from the southern Scotia Sea. It had a limited size range, but there was clear size‐related sexual dimorphism with males significantly larger than females. The species had a life cycle of c. 2 years, but the I‐group (c. 1 year old, 1 November to 31 October the next year) occurred only in regions close to the APF suggesting that recruitment is restricted to these waters. A seasonal southward migration for P. choriodon is likely as the species occurred mostly to the south‐west of South Georgia in summer, but extended to the sea‐ice sectors in autumn. Protomyctophum choriodon had a life cycle of 4+ years in the Scotia Sea and the population was dominated by age classes >3 years old. Larval stages were absent during the surveys for all species. Diurnal variations in vertical distribution were apparent for all three species. Interspecific variations in diet were evident, but all species were primarily copepod feeders, with Metridia spp., Rhincalanus gigas and Calanus simillimus generally dominating their diet. Small euphausiids, principally Thysanoessa spp., were also an important component of their diets, particularly for P. choriodon which had the largest body size. The spatial and temporal variations in diet for both P. bolini and P. tenisoni were broadly consistent with underlying abundance patterns within the mesozooplankton community.     

Myctophid (Myctophidae) Abundance and Ecology in the Gulf of Alaska in Winter

Russian Journal of Marine Biology - The distribution and abundance of four common myctophid fish species in the upper epipelagic layer of the northeastern North Pacific in winter were analyzed...     

Age and growth of Brauer's lanternfish Gymnoscopelus braueri and rhombic lanternfish Krefftichthys anderssoni (Family Myctophidae) in the Scotia Sea,Southern Ocean

This study examines age and growth of Brauer's lanternfish Gymnoscopelus braueri and rhombic lanternfish Krefftichthys anderssoni from the Scotia Sea in the Southern Ocean, through the analysis of annual growth increments deposited on sagittal otoliths. Otolith pairs from 177 G. braueri and 118 K. anderssoni were collected in different seasons from the region between 2004 and 2009. Otolith-edge analysis suggested a seasonal change in opaque and hyaline depositions, indicative of an annual growth pattern, although variation within the populations of both species was apparent. Age estimates varied from 1 to 6 years for G. braueri (40 to 139 mm standard length; L_S) and from 0 to 2 years for K. anderssoni (26 to 70 mm L_S). Length-at-age data were broadly consistent with population cohort parameters identified in concurrent length-frequency data from the region for both species. The estimated values of von Bertalanffy growth curves for G. braueri were L_∞ = 133.22 mm, k = 0.29 year⁻¹ and t₀ = −0.21 year and the values for K. anderssoni were L_∞ = 68.60 mm, k = 0.71 year⁻¹ and t₀ = −0.49 year. There were no significant (P > 0.05) differences in growth between sexes for either species, suggesting that males and females have similar growth and development trajectories in the Scotia Sea. A positive allometric relationship between L_S and wet mass was found for each species, as well as a significant (P < 0.0001) linear relationship between otolith size and L_S. Growth performance (Ф′) was similar between the two species and congruent with other myctophid species across the Southern Ocean. This study provides important parameters for future Southern Ocean ecosystem studies in a resource management context.     

Structure and Function of the Vertebrate Pineal Gland

This review presents data from the literature on structure and function of the pineal gland. Discussed are the histological and ultrastructural characteristics of the gland, its function according to novel results, peculiarity of synthesis and secretion of melatonin and its function, as well as the role of the pineal gland in circadian organization of organisms. The problems of evolution of the pineal function in the row of vertebrates are considered.     

Age and growth of Benthosema pterotum (Alcock, 1890) (Myctophidae) in the Oman Sea

Juvenile and adult specimens of Benthosema pterotum (skinnycheek lanternfish) were collected during several surveys conducted on the Iranian continental shelf of the Oman Sea. Age was estimated by enumeration of growth increments in sagittae otolith sections on the assumption of their daily deposition. Three distinct growth zones in otolith microstructure (central, middle, and external) were defined. These three zones presumably represent increments deposited during successive life history stages, characterized by a different migratory behavior and depth occurrence. The number of increments in the central zone of the B. pterotum otolith (26.8 on average) was thus far one of the lowest in myctophid species studied. A negative correlation between the number of increments in the central and middle zones was observed. This might suggest a functional relation between these two periods of early life history, when fewer larvae in the epipelagic layers may be compensated by a longer non‐migratory behavior of metamorphosis larvae and early juveniles. The maximum number of growth increments in B. pterotum otoliths, i.e. 315, indicated a short lifespan of probably <1 year. The relationship between otolith length and standard length was described by linear regression model (r² = 0.902), and between the body length and weight as an isometric growth in 274 juvenile and adult specimens (r² = 0.922). The growth model estimated only for juveniles and adults was curvilinear (SL = 1.150 × Age^0.616; r² = 0.868). Back‐calculated hatch dates might suggest a spawning season of B. pterotum from May to September, but due to the limited number of investigated specimens a prolonged spawning cannot be excluded. Further trials are needed to measure the population parameter dynamics.     

The Only Known Jawed Vertebrate with Four Eyes and the Bauplan of the Pineal Complex

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Growth and mortality of larval Myctophum affine (Myctophidae,Teleostei)

The growth and mortality rates of Myctophum affine larvae were analysed based on samples collected during the austral summer and winter of 2002 from south‐eastern Brazilian waters. The larvae ranged in size from 2·75 to 14·00 mm standard length (L_S). Daily increment counts from 82 sagittal otoliths showed that the age of M. affine ranged from 2 to 28 days. Three models were applied to estimate the growth rate: linear regression, exponential model and Laird–Gompertz model. The exponential model best fitted the data, and L₀ values from exponential and Laird–Gompertz models were close to the smallest larva reported in the literature (c. 2·5 mm L_S). The average growth rate (0·33 mm day^?1) was intermediate among lanternfishes. The mortality rate (12%) during the larval period was below average compared with other marine fish species but similar to some epipelagic fishes that occur in the area.     

The fifteenth- and twentieth-century colonization of the Basin of Mexico by the Great-tailed Grackle (Quiscalus mexicanus)

Historical evidence indicates that Great‐tailed Grackles colonized the Basin of Mexico from the Gulf Coast lowlands in the fifteenth century. They were probably assisted by an intentional introduction, but colonization succeeded because of anthropogenic habitat alterations over the previous two centuries. During the Colonial period, grackles withdrew from the Basin, only to recolonize it in recent decades. This withdrawal was also due probably to changes in land use, including drainage of much of the water from the Basin's lakes.     

Cooperative breeding behaviors in the Hawaiian Stilt (Himantopus mexicanus knudseni)

Cooperative breeding, which is commonly characterized by nonbreeding individuals that assist others with reproduction, is common in avian species. However, few accounts have been reported in Charadriiformes, particularly island‐nesting species. We present incidental observations of cooperative breeding behaviors in the Hawaiian Stilt (Himantopus mexicanus knudseni), an endangered subspecies of the Black‐necked Stilt (Himantopus mexicanus), during the 2012–2020 nesting seasons on the Hawaiian islands of O‘ahu and Moloka‘i. We describe two different behaviors that are indicative of cooperative breeding: (a) egg incubation by multiple adults; (b) helpers‐at‐the‐nest, whereby juveniles delay dispersal and reproduction to assist parents and siblings with reproduction. These observations are the first published accounts of cooperative breeding in this subspecies and merit further investigation, as cooperative breeding may improve population viability of the endangered, endemic Hawaiian Stilt.     

The range expansion of the great-tailed grackle (Quiscalus mexicanus Gmelin) in North America since 1880

Aims This study aimed to document and describe the current range expansion of the great‐tailed grackle (Quiscalus mexicanus Gmelin) into the USA. By examining the habitat associations and pattern of spread of this species, I intended to determine the factors responsible for this remarkable expansion by a tropical species into a temperate environment. Location This study focused on the spread of the great‐tailed grackle in the continental USA, Canada and Baja California. Methods I used published records, museum specimens, and egg collections to document this range expansion from 1880 through 2002. In addition I surveyed large portions of Arizona, Nevada, southern Utah and southern California for great‐tailed grackles during 2000 and 2001. The data gathered was used to create maps in order to quantify the rate of spread of this species. Results Between 1880 and 2000 the great‐tailed grackle expanded its breeding range in the USA from c. 64,000 km² to more than 3,561,000 km², an increase of 5530%. The average annual rate of increase is 3.4%, but has lessened during the past 20 years. Northward movement in the eastern portion of the range has slowed down, reflecting this decrease. However, in the central and western portion of the species range, the rate of northward movement is still accelerating. During this expansion, the average time between first sighting in a state and first breeding was 5.8 years. The species has become less migratory during its range expansion, wintering in 17 of the 20 states where it breeds. Main conclusions This range expansion has been marked by great‐tailed grackles preferring human‐modified environments as breeding grounds, especially in the western states. This association appears to benefit the species in two ways; nest predation is lessened in such areas compared with natural conditions, whereas human activities tend to generate an abundant and consistent food supply for feeding offspring. Wintering birds are often associated with cattle feed lots and large‐scale dairies, where abundant waste grain provides them with a reliable food supply. Given the continued human population increase throughout large areas of the western USA, the great‐tailed grackle will continue its range expansion.     

On species composition and distribution of lanternfish larvae (Myctophidae) in the eastern South Pacific

The results of the study of species composition and distribution of lanternfish larvae (Myctophidae) in July through September of 1980 in open waters of the eastern South Pacific in areas situated beyond the 200-mile zones of Ecuador, Peru, and Chile are provided. In collections of ichthyoplankton from this region, larvae of 19 taxonomic forms of myctophids were found, of which the eastern Pacific endemic Diogenichthys laternatus ranked first by numbers and frequency of occurrence. Specific features of distribution of larvae of the most abundant species were considered, and the map of the total distribution density of larvae of all species of myctophids in the study area was compiled. It was found that their highest concentrations were recorded in the zone of the equatorial front in the north of the region near the boundary with the 200-mile zone near the Galapagos Islands, and that these aggregations consisted mainly of larval D. laternatus. Large concentrations of larval myctophids were attributed to strong convergent zones. Based on collected materials, the tentative value of total numbers of larval myctophids during the survey was calculated.     

Morphology of the pineal complex in seven species of lanternfishes (Pisces: Myctophidae)

The morphology of the pineal complex was compared in seven species of lanternfishes (family Myctophidae) using both light and electron microscopes. On the basis of compactness of the pineal end-vesicle and presence or absence of a dorsal sac, the species in this study were divided into two groups. This grouping seems to correlate well with current views on the phylogenetic relationships among these fishes. Receptor cells and supportive cells are described in the pineals of all species examined. The deepest-dwelling of the forms studied, Parvilux ingens, showed a significant increase in the mean number of lamellar membranes in the outer segments of the receptor cells and a higher convergence ratio of receptor cells to ganglion cells as compared to the shallow-dwelling form Tarletonbeania crenularis. Accordingly it is suggested that the pineal of P. ingens is more photosensitive. Additional differences among species were found in the ultrastructure of the supportive cells. Dorsal sacs were absent in the three shallowest-occurring myctophids studied. In those species with a dorsal sac, its close association with the pineal-end-vesicle suggests a functional relationship between the two structures.