Morphological development of the swim bladder in hatchery-reared striped trumpeter Latris lineata

This study examined swim bladder morphogenesis in three cohorts of striped trumpeter (Latris lineata), a euphysoclist species with physostomous larvae. The swim bladder was first discernible 1–2 days after hatching as an evagination on the dorsal surface of the incipient digestive tract. It comprised a cluster of mesenchymal cells surrounding an inner primordium of epithelial cells. At mouth opening in larvae of 5.3 mm standard length (SL), the swim bladder was noticeably enlarged. Histologically, the swim bladder lumen was dilated and liquid filled. The pneumatic duct was first seen during the dilation stage and the rete mirabile began forming among the connective tissue surrounding the swim bladder. Initial swim bladder inflation occurred on day 11 post‐hatching in Cohort 1, at 14°C, and day 9 post‐hatching, in Cohorts 2 and 3, at 16°C. Histologically, the lumens of inflated swim bladders were ellipsoid and the epithelium was squamous, except for cuboidal gas gland cells at the anterio‐ventral and anterio‐lateral regions of the swim bladder. During the initial inflation interval the pneumatic duct was dilated in larvae both with and without swim bladder inflation. The pneumatic duct began to regress in some larvae over 7.5 mm SL. The swim bladder of striped trumpeter was similar to larvae of other altricial perciform marine fish in respect to organ derivation, tissue differentiation, luminal dilation and initial gaseous inflation. However, variations, particularly the delay in initial swim bladder inflation until after the start of feeding, were observed that could be fundamental to problems encountered during larval rearing.     

Visual field of cultured striped trumpeter Latris lineata (Teleostei) larvae feeding on rotifer prey

The visual field of striped trumpeter Latris lineata larvae fed rotifer prey was determined from analysis of feeding behaviour in the horizontal plane. The visual field was forward and laterally directed, characterised by maximum reactive distances (distance at which the predator first detects and reacts to the prey) of 5.07 mm and 5.25 mm on days 13 and 17 post-hatching, respectively, 97% of mean larval length. This confirmed the predicted horizontal visual field, forward and laterally directed, derived from higher cone cell densities in the dorso-temporal and medial regions of the retina compared with ventral regions. The visual field of prey detection expanded laterally with ontogeny as a wider range of reactive angles was used by 17 day-old than 13 day-old larvae. Larvae displayed a saltatory searching pattern, periodically stopping to scan for prey throughout the visual field, and exhibited a side-to-side movement of the head as they approached and stopped, prior to striking at a detected prey item. Larvae on day 17 post-hatching terminated 35% of feeding sequences at the pre-strike position, at a mean distance from prey of 0.58 mm.     

Sperm survival during short-term storage and after cryopreservation of semen from striped trumpeter (Latris lineata)

Methods of short-term storage and cryopreservation were examined for semen from striped trumpeter (Latris lineata). For fresh semen at 18 degrees C, the percentage of motile sperm declined rapidly from over 80% immediately after activation with sea water to less than 2% within 9 min after activation. The motility after activation of undiluted fresh sperm stored at 5 degrees C was maintained for two days and then declined markedly so that by the eighth day, sperm were mostly immotile after activation. The post-thawing motility was higher for sperm frozen with a non-activating diluent containing 2.84 M DMSO in saline (117 mM NaCl) than in an activating glycerol (2 M) medium in dilute sea water (300 mOsm). Post-thawing motility was higher for a dilution rate of 1:5 (semen:diluent) than 1:2 or 1:11 but was similar when frozen semen was thawed at 10 degrees, 20 degrees or 30 degrees C. For semen stored at a range of volumes as pellets frozen on dry ice (0.2 to 2.0 mL) or straws frozen in liquid nitrogen vapor (0.25 to 0.5 mL) and thawed in a waterbath at 20 degrees C, the post-thawing motilities were similar even though the patterns of cooling and thawing differed markedly between methods of freezing and sizes of pellets and straws.     

Length‐weight and length‐length relationships of two gobiid fishes Eleotris fusca (Forster, 1801) and Odontamblyopus rubicundus (Hamilton, 1822) from the Payra River,southern Bangladesh

The present study provides the estimates of length‐weight relationships (LWRs) and length‐length relationships (LLRs) of two gobiid fishes Eleotris fusca and Odontamblyopus rubicundus from the Payra River, southern Bangladesh. Fish samples were collected from the set bagnet (mesh size <2 mm) fishers of the Payra River in July 2016. Allometric coefficient (b) values were 2.95 for E. fusca and 2.76 for O. rubicundus. Additionally, the LLRs were highly significant with r² ≥ .955. While the estimate of the LWR for O. rubicundus includes a substantial larger sample size and thus provides a more reliable LWR than the one published so far, the LWR for E. fusca must be considered as tentative because the sample includes only juveniles for a fish that reaches a maximum standard length more than three times as much. Additional studies are needed to further improve our LWR knowledge base for these fish species.     

Ultrastructural study of oogenesis in Monocelis lineata (Turbellaria,Proseriata)

Summary

Oogenesis in the marine turbellarian proseriat Monocelis lineata was investigated at the ultrastructural level. Oocyte differentiation is not synchronous so that successive stages of germ cell maturation were simultaneously detected in each of the two ovaries. Each developing oocyte is enveloped by follicle cell projections which are presumably involved in a morphologically undetectable support of vitellogenesis. The main features evidenced during oocyte differentiation are: (1) The synthesis of cortical granules by the rough endoplasmic reticulum and Golgi complex, occurring in the earlier stages of oogenesis; (2) The synthesis of yolk globules by the rough endoplasmic reticulum (RER) and Golgi complex, occurring in the later stages of oogenesis, namely late meiotic prophase I. Neither morphologically visible endocytotic activity, nor the presence of intercellular bridges, nor even the development of microvilli were observed at the oolemma or cortical ooplasm, so that the sole mechanism of vitellogenesis appears to be autosynthetic. The significance of these findings is discussed in relation to the taxonomic position of M. lineata and more generally in relation to the phylogenetic history of the class Turbellaria.     

Rabies challenge of captive striped skunks (Mephitis mephitis) following oral administration of a live vaccinia-vectored rabies vaccine

Twenty-four adult striped skunks (Mephitis mephitis) were administered the raccoon product formulation of Rabies Vaccine, Live Vaccinia-Vectored (Raboral V-RG, Merial Limited, Athens, Georgia, USA), either by oral instillation or in vaccine-filled coated sachets either as single or multiple doses. A control group remained unvaccinated. Twenty-three of the skunks were challenged 116 days postvaccination with rabies virus (skunk isolate). Six of six naive skunks succumbed to challenge. Four of six skunks that received the vaccine by oral instillation survived challenge. The skunks that did not survive failed to seroconvert following vaccination. None of the skunks that accepted multiple doses of the vaccine offered in coated sachets survived challenge, nor were rabies virus-neutralizing antibodies (VNAs) detected in the sera. Likewise, none of the five skunks ingesting a single sachet developed VNA against rabies. However, in this group one skunk did survive rabies challenge. This preliminary study showed that the vaccinia-vectored oral rabies vaccine Raboral V-RG, as formulated for use in raccoons, is capable of protecting a percentage of skunks against rabies. However, although the fishmeal-coated sachets were readily consumed, subsequent challenge of these animals revealed poor vaccine delivery efficiency.     

Growth and development of the Tasmanian devil (Sarcophilus harrisii) at Healesville Sanctuary,Victoria, Australia

A study of the growth and development of the Tasmanian devil (Sarcophilus harrisii) was undertaken on a litter born at Healesville Sanctuary in Healesville, Victoria, Australia. Measurements of crown–rump length, head length, and head width were recorded every week from birth. Body weight was recorded weekly once the joeys were detached from the teat at 142 days of age, until 218 days of age. The growth curves revealed an initial linear increase in crown–rump lengths until approximately 60 days of age, when the gradient increased, while head length and head width showed a largely linear increase with age. The appearances of various morphological characteristics were also recorded. Zoo Biol 22:497–505, 2003. © 2003 Wiley‐Liss, Inc.     

Influence of latitudinal variation in environmental gradients and population structure on the demography of a widespread pelagic fish, <Emphasis Type="Italic">Arripis trutta</Emphasis> (Forster, 1801)

Knowledge of the influence of both spatial and temporal environmental gradients on life history traits and population demographics is a critical requirement in the management of exploited fish populations. This study examined variation in the demographics of Arripis trutta, an economically-important pelagic fish species with a broad latitudinal distribution in the waters of coastal south-eastern (SE) Australia, a region dominated by the influence of the East Australian Current (EAC). A validated ageing protocol was first developed using sectioned sagittal otoliths, which in turn permitted examination of latitudinal variation in A. trutta growth, size compositions and age compositions. The von Bertalanffy growth function parameters for A. trutta in SE Australia were estimated to be L _∞?=?63.20?±?0.37 cm fork length (FL), k?=?0.26?±?0.01 yr^?1 and t _o?=??0.14?±?0.03 yr, with a maximum estimated age of 12.7 years. Growth was shown to be faster with decreasing latitude likely due to a simple relationship with the latitudinal gradient in water temperature; fastest growth occurring in northern NSW and slowest growth occurring in Tasmania. Latitudinal patterns in growth were remarkably similar to those previously reported for this species, despite age being estimated using scale readings some 40 years ago. This consistency in latitudinal growth patterns of a temperate fish can be attributed to the life history-related movements undertaken by A. trutta in this region. This temporally-consistent movement pattern is supported by the spatial gradient in the size and age composition of A. trutta sampled from different latitudes in both the current and historical research, whereby numbers of large and old fish increase progressively from Tasmania to northern NSW. These results highlight the need to consider the potential for spatial size- or age-structuring in the development of sampling designs and interpretation of results for any study examining spatial or temporal variation in demographic parameters of exploited fish populations.     

Rediscovery of Tomarus cuniculus (Fabricius, 1801) (Coleoptera: Scarabaeidae: Dynastinae) in Mexico

After more than 80 years, the rediscovery of Tomarus cuniculus in Mexico is presented based on two male specimens recently collected from Tabasco. Historical records from the literature are reviewed. A modification to the identification key of the species of Tomarus in Mexico is provided.     

Trypauchen vagina (Bloch & Schneider, 1801) a new established species in the Southwestern Atlantic

Trypauchen vagina (Bloch & Schneider, 1801) is a goby that lives burrowed into the substrata feeding on small invertebrates. It is native to the Indo-pacific region, ranging from Kuwait to China. Recently, this fish has been reported outside the original range of distribution, being found in the Mediterranean Sea, and more recently in the northeastern Brazilian coast. The Mediterranean reports are usually associated with Lessepsian migration, while the reports from Brazil are possibly related to ballast water transportation. In the present work, we provide eight new records from southeastern Brazilian coast, all made in São Paulo state, far from the first record. These additional records raised concern since the presence of an alien species could implicate in environmental and economic losses. Thus, we decide to model the environmental suitability for this goby in the Brazilian coast, specially focusing on major ports, usually places with high ballast water propagule pressure. In addition, an analysis of the suitability in the Red Sea was also made, to verify the hypothesis of Lessepsian migration. The results revealed that temperature and primary productivity are among the most important parameters for the presence of T. vagina, also indicating a high environmental suitability for this species in the Red Sea and Brazilian coast, especially in southeastern region, where the new records were made. Due to the number of collected individuals, it is hard to affirm that this taxon presents a self-sustaining population in Brazilian waters, but the several registers, in different locations and different life stages point to an establishment of the species in this new region. This population status allied with a high environmental suitability is alarming and should motivate new studies concerning T. vagina in Brazilian waters.     

The existence of a glycogenic body in the spinal cord of a cyprinodontiform teleost,Jenynsia lineata (Jenyns 1842)

Summary A distinct spinal cord structure is described in the teleostean fish J. lineata wich occupies the medial dorsal aspect of the cord, and extends in depth from the dorsal surface to the tectum of the central canal. This structure is characterized by the presence of large quantities of glycogen; this feature makes it similar in certain aspects to the glycogenic body of birds. The name of glycogenic body has been proposed for this structure.     

Estimating femur and tibia length from fragmentary bones: an evaluation of Steele's (1970) method using a prehistoric European sample.

Steele's (1970) regression method for estimating femur and tibia length from fragmentary bones is tested on a sample of complete femora (female N = 26; male N = 33) and tibiae (female N = 16; male N = 22) from a number of European Mesolithic and Neolithic sites. Over half of the regression equations given by Steele for predicting maximum length of the bone from the length(s) of one or more of its constituent segments are shown to produce inaccurate predictions in this test sample. However, a closer evaluation of these results, including calculation of regression equations for the test sample itself, reveals that this inaccuracy does not derive from any inherent flaw in Steele's method. Rather, it is shown that differential distribution of maximum bone length among the various bone segments as defined by Steele may occur due to variation in muscular activity pattern and intensity. This argues for the retention of Steele's basic method, with care being taken to match closely the activity pattern typical of the sample from which regression equations are derived with that of the population to which the equations are to be applied. The equations calculated in this study thus are provided for use where deemed appropriate.     

Tasphorura, a new genus of Tullbergiinae (Collembola: Onychiuridae) abundant in Tasmanian Nothofagus forest

Abstract. Tasphorura , a new genus of onychiurid Collembola, is erected for an unusually coloured species, Tasphorura vesiculata n.sp., found at a single locality in Tasmanian Nothofagus rainforest. Its isolated phyletic position is noted and extremely high densities are recorded. The conservation implications of the restricted distribution shown by this species, which is typical of many rainforest invertebrates, are discussed with reference to increasing utilization and fragmentation of these forests.     

Phenotypical traits and gonadal development in mangrove land crab,Ucides cordatus (Decapoda: Ocypodidae)

Castilho, G.G., Ostrensky, A., Pie, M.R. and Boeger, W.A. 2010. Phenotypical traits and gonadal development in mangrove land crab, Ucides cordatus (Decapoda: Ocypodidae). —Acta Zoologica (Stockholm) 92 : 393–397. The association between phenotypical and reproductive traits has been the focus of considerable research in decapod crustaceans, particularly with the goal of facilitating the management and sustainable use of natural stocks of commercial interest. The goal of the present study is to evaluate the existence of a relationship between ovarian maturation and the coloration of the ovary and carapace of Ucides cordatus using histological methods and macroscopic observation. Monthly samples of adult females were obtained between October 2002 and March 2005 in mangroves of the Baía de Antonina, Southern Brazil (25º25′S; 48º42′W). A total of 367 specimens were collected throughout the study. Each specimen was classified subjectively into five ovarian colorations (whitish, yellow, orange, brown, and purple) and five carapace colorations (yellow, blue, dark gray, brown, and purple). Although substantial differences in ovarian development were found among females with different carapace and ovarian colorations, the variability within each class precluded their use as reliable indicators of ovarian development.     

Cross sectional area measurement of tendon and ligament in vitro: a simple, rapid, non-destructive technique

The structural properties of tendons and ligaments are integral to their ability to function effectively in vivo and are determined from both the geometrical form and material properties. Many studies of tendon and ligament include a mechanical assessment of the structure in vitro. However, to determine the material properties of the constituent tissues it is necessary to measure cross-sectional area (CSA). Problems associated with this include damage to the structure, inaccurate values for non-uniform shapes, labour intensive techniques or requirement of expensive equipment. We describe a non-destructive technique for measurement of tendon and ligament CSA based on that of Race and Amis (J. Biomech. 29 (1996) 1207). The modified technique uses aqueous rapid curing alginate dental impression paste, digital photography and computerised image analysis. This technique is quick and simple to carry out and provides accurate values (within 0.8%) for CSA which are reproducible (coefficient of variation = 1.42%). The technique is non-destructive and can be used on specimens with an irregular shape.     

Histological analysis of gonadal development in Patagonotothen tessellata (Richardson 1845) (Nototheniidae: Pisces) from the Beagle Channel, Argentina

Histological analysis of gonadal development in Patagonotothen tessellata (Richardson 1845) was carried out over a 3-year period (1987–1989) on samples from the Beagle Channel, Tierra del Fuego, Argentina. Testicular structure is defined as of the 'unrestricted spermatogonial type'. Maturation processes of cysts are synchronized in the various tubules. This degree of synchronization, as well as the characteristic of the different cellular types, permits definition of four spermatogenetic stages. Patagonotothen tessellata is defined as a total spawner according to ovocitary development and oocyte diameter frequency distribution analyses. Oocyte reabsorption and the likely consequences thereof on reproductive potential are also analysed. Patagonotothen tessellata is the first species of Nototheniids for which annual double spawning (winter and summer) and nonbiennial gonadal maturation processes are described.     

Evaluation of a non-destructive method for determining egg composition using total body electrical conductivity (TOBEC) measurements

It is widely assumed that there is a positive relationship between egg quality (or egg size) and offspring fitness. However, obtaining unequivocal data in support of this hypothesis has been hampered by the lack of any method for non-destructive determination of egg composition, preventing a direct analysis of egg quality and subsequent chick growth and survival in the same egg(s). In this paper, we describe the application of a rapid, non-destructive technique using measurement of total body electrical conductivity (TOBEC) for determination of egg composition in intact eggs. The TOBEC index was positively and highly correlated with egg lean mass and with the mass of some egg components (albumen and water content). Values for predicted lean mass, based on the regression equation for lean mass against TOBEC index, were within ±6% of actual lean mass. Egg lipid mass was most accurately predicted (±15%) using a multiple regression model, with fresh egg mass and TOBEC index included as independent variables. Egg temperature, and the position of the egg in the sampling chamber, markedly affected the TOBEC index obtained.