Isolation and characterization of novel microsatellite loci for the short‐beaked common dolphin (Delphinus delphis) and cross‐amplification in other cetacean species

Seven tetranucleotide and three dinucleotide microsatellite loci were isolated from the short‐beaked common dolphin (Delphinus delphis). Number of alleles and observed heterozygosity ranged from three to twelve (mean 8.4) and from 0.087 to 0.978 (mean 0.741), respectively. All loci were tested in four other odontocete species and showed polymorphisms in most locus–species combinations. This panel of nuclear markers will be useful for the investigation of population ecology and social interactions in common dolphins and other cetacean species.     

IDENTIFICATION OF GEOGRAPHIC FORMS OF COMMON DOLPHIN (Delphinus delphis) FROM AERIAL PHOTOGRAMMETRY

Abstract: At least four morphologically distinct forms of common dolphins are found in the eastern Pacific, We compared length data for common dolphins photographed from the northern, central and southern regions as defined by Perrin et al. (1985) and found significant differences in average length for adult animals (>150 cm) and for "adult females" defined for our purposes as animals accompanied by calves. Analyses of calculated birth dates for calves demonstrated differences in timing of reproduction between the geographically adjacent forms. Length distributions from aerial photographs and samples collected from the purse seine fishery were strikingly similar. This work demonstrates a new, non-invasive method for obtaining unbiased life history and morphological data.     

GEOGRAPHIC PATTERNS OF VARIATION IN OFFSHORE SPOTTED DOLPHINS (STENELLA ATTENUATA) OF THE EASTERN TROPICAL PACIFIC OCEAN

The spotted dolphin (Stenella attenuata), a species commonly associated with the tuna fishery, is widely distributed in the eastern tropical Pacific Ocean (ETP). Geographic patterns in morphological characteristics of this dolphin were evaluated for 36 skull measurements of 574 museum specimens allocated to 5° latitude-longitude blocks. A strong subdivision between northern and southern offshore populations was demonstrated using principal components, canonical variates and cluster (UPGMA and function-point) analyses of block means derived from standardized, sex-adjusted measurements. Classification functions derived from a stepwise multiple discriminant analysis correctly identified more than 87 percent of the specimens as being from either a northern or southern locality. These results support recognition of southern spotted dolphins as a separate management stock. Dolphins from a sample representing a far-western locality show similarities with those from the south. Patterns of geographic variation in morphology were evaluated using Mantel tests and matrix correlations; 17 of the 36 characters showed regional patterning and 18 exhibited local patterning. Morphological trends were also assessed with respect to 14 oceanographic measures that characterize environmental variability in the ETP. In general, clinal variation in morphology mirrors a north-south trend found in several environmental variables. Overall, the most striking associations between morphological and environmental variables involved Solar Insolation (Jan.). Sea surface temperatures also exhibited a strong association with morphological variables; the highest correspondence was found between width of the temporal fossa and sea surface temperature in July. In addition, the thickness of the oxygen minimum layer exhibited a pattern of variation that was statistically associated with 58 percent of the skull characters. The geographic patterns found for cranial morphology and environmental measures are strongly clinal and in general congruent, suggesting that oceanographic conditions in part determine trends in morphological characteristics of spotted dolphins.     

TAXONOMIC STATUS AND GEOGRAPHICAL CRANIAL VARIATION OF COMMON DOLPHINS (DELPHINUS) IN THE EASTERN NORTH ATLANTIC

The common dolphin has a widespread distribution and is relatively abundant in the temperate to subtropical waters of the eastern North Atlantic. However, it is not known whether different species, subspecies, or populations occur in this region. We examined 393 common dolphin skulls obtained from both stranded and bycaught individuals collected between 1901 and 2005. The series included skulls of 152 females and 199 males, from animals ranging in body length from 93 to 230 cm and 105 to 244 cm, respectively. The ranges of total body length, skull size, RL/ZGW ratio and maximum upper alveolar (tooth) count of common dolphins in the eastern North Atlantic overlapped with those of both short- ( D. delphis ) and long-beaked ( D. capensis ) species found off the Californian coast. However, in the absence of additional data, the common dolphin in the eastern North Atlantic is regarded here as a large form of Delphinus delphis . Sexual dimorphism and possible sex-linked characters were identified within the sample. Results of the current study indicate some population differentiation within the eastern North Atlantic, with common dolphins off Portugal showing segregation in morphometric characteristics from common dolphins in other areas.     

External morphology of the short-beaked common dolphin, Delphinus delphis: growth, allometric relationships and sexual dimorphism

Growth, allometric relationships and sexual dimorphism are described from measurements of 105 male, 149 female and 38 unsexed specimens of short‐beaked common dolphin, Delphinus delphis, stranded along the Irish coastline (53.8% of the sample) or by‐caught in fisheries (46.2% of the sample), from 1990 to 2003. For each dolphin, 24 external body length measurements were recorded. Ages were determined for 183 dolphins by analysis of growth layer groups in the dentine. Males ranged in total body length (TBL) from 105 to 231 cm and females from 93 to 230 cm, with a maximum age of 25 years obtained for both sexes. Using a single Gompertz growth curve, asymptotic values obtained for TBL were 211.6 cm and 197.4 cm for males and females, respectively. Asymptotic lengths were attained at 11 years in males and 9 years in females. The gestation period was estimated to last approximately 11.5 months. Sexual size dimorphism (SSD) was evident, with males being significantly larger than females for 20 of the characters measured, and an SSD ratio of 1.06 was obtained. Sexual shape dimorphism was lacking, except for the presence of prominent postanal humps in mature males.     

A revision of the Zygothrica samoaensis species group (Diptera: Drosophilidae), with division into three species subgroups and description of five new species

This revision deals with the Zygothrica samoaensis species group, which includes 15 species, five of which are described as new to science. Two synonymies are proposed: Z. vietnamensis Grimaldi, 1990, as a junior synonym of Z. flavofinira Takada, 1976, and Z. britannia Grimaldi, 1990, as a junior synonym of Z. malaysiana Grimaldi, 1990. The samoaensis group is divided into three species subgroups: (i) the samoaensis subgroup, consisting of nine species, including a new species, Z. australiaensis sp. nov.; (ii) the fijiana subgroup of Z. fijiana Takada, 1976, and two new species, Z. triscutellaris sp. nov. and Z. bicornigera sp. nov.; and (iii) the leptorostra subgroup of Z. leptorostra Grimaldi, 1990, and two new species, Z. pimacula sp. nov. and Z. quintamaculata sp. nov. Supplementary information on geographic distribution is provided for some species, as well as a key to all species of the samoaensis group. Zygothrica kokodana Grimaldi, 1990, and Z. paleovitta Grimaldi, 1990, have closer affinity with the hirticornis and the quadrivittata species groups, respectively, and so are moved to the corresponding genus Hirtodrosophila.     

Biodiversity patterns in Indian Ocean corals, and effects of taxonomic error in data

Corals from 26 sites in the Indian Ocean, from numerous taxonomic sources, are analysed for distribution patterns after applying a consistent synonymy. The data set contains double the amount of distribution information used previously. Cluster analysis shows several contiguous regional groupings within this ocean, and no geographically dispersed groupings exist. Between-site species similarity correlates negatively with distance between sites. Coral species diversity and genus diversity plotted with latitude and longitude confirm that a band of high diversity stretches across the entire Indian Ocean, but that in this Ocean, unlike the Pacific and greater Caribbean area, there is no clear gradient with latitude at least up to the latitudinal limits of coral growth. About half the species are widespread throughout the Indian Ocean. Species frequency/distribution curves and cumulative frequency curves show that 150 species occur at only 2–4 sites. Multi-dimensional scaling (MDS) analysis using only these species confirms that they are important in forming sub-regional groupings which are superimposed on a general Indian Ocean homogeneity.The perennial problem of error in taxonomic data sets is examined. Increasing taxonomic error is introduced into the data using random methods. It is found that about 25% more error can be added to this data set before the relationship between similarity coefficient and geographical distance between pairs of sites is lost. Measures extracted from the clustering procedure using the original data and the data sets with added taxonomic error, show a sharp loss in cluster formation after addition of about 10 or 20% more error.     

THE DISTRIBUTION OF WHITE-SIDED (LAGENORHYNCHUS ACUTUS) AND COMMON DOLPHINS (DELPHINUS DELPHIS) VS. ENVIRONMENTAL FEATURES OF THE CONTINENTAL SHELF OF THE NORTHEASTERN UNITED STATES

Sightings of white-sided ( Lagenorhynchus acutus ) and common dolphins ( Delphinus delphis ) from survey vessels operating on the continental shelf of the northeastern United States were recorded during spring and fall of six years. Distributions of these sightings were compared with sea surface temperature and salinity, and bottom topography. The apparent geographic distributions of the two species are complementary, although there is a broad overlap. White-sided dolphins occurred primarily within the Gulf of Maine, but also on Georges Bank and in the mid-Atlantic region. Common dolphins were abundant within a broad band paralleling the continental slope (100–200 m depth contour) from latitude 35°N to the northeast peak of Georges Bank. Sightings of this species were distributed primarily along the edge of the continental shelf south of 40°N in spring and north of this latitude in fall. Few sightings of common dolphins occurred in the Gulf of Maine.
Although both species of dolphins were sighted more frequently in areas of high sea floor relief, white-sided dolphins occurred in areas where sea surface temperatures and salinities are low while common dolphins were sighted in warmer, more saline waters. However, these environmental conditions may be only secondarily influencing dolphin distribution. Seasonal variation in sea surface temperature and salinity, and local nutrient upwelling in areas of high sea floor relief may affect preferred prey abundances, which in turn may affect dolphin distribution.     

中华白海豚3 个MHC 基因座位遗传变异的初步分析

主要组织相容性复合体(Major histocompatibility complex,MHC) 基因是由一组紧密连锁的基因组成,是哺乳动物免疫系统中最重要的组成部分。本文选择3 个MHC 基因座位的第二外元,即:MHC-I 类基因和II 类基因的DRA 和DQB 座位,初步调查濒危物种中华白海豚的遗传变异。共鉴定了2 个DRA、2 个DQB 和7 MHC-I等位基因。DRA 座位遗传变异非常低,而DQB 和MHC-I 座位具有相对较高水平的遗传变异。并且,在DQB 和MHC-I 基因座位的假定的抗原结合位点(Antigen binding sites,ABS),非同义替代明显大于同义替代,提示平衡选择(Balancing selection)维持这两个座位的多态性,而在DRA 座位上,并没有检测到平衡选择。系统发生分析表明中华白海豚的MHC 等位基因没有聚在一起,而是和其他的物种聚在一起,符合MHC 跨种进化(Transspecies evolution)的模式。     

海南三亚一头死亡中华白海豚的形态学记录

On February 2,2015, a dead female Indo-Pacific humpback dolphin (Sousa chinensis) was found in the coastal water of Meilian Village, Yacheng Town, Sanya City, Hainan Province, China. It was the first Indo-Pacific humpback dolphin death case ever found in waters southwest of Hainan Island. In the present study, data about external morphology and skeleton system of the dead dolphin were documented, Body length and body mass of the animal were 235.0 cm and ca. 150 kg, respectively, with completely white body color. The cranium of this dolphin wa 189 mm in zygomatic width, and 415 mm in skull length. Its vertebra formula was C6+T12+L10+Ca20=48. It had 12 pairs of ribs and 11 V-bones. According to previous reports, our skeleton sample may have one cervical vertebra missing, and one or more caudal vertebras and V bones missing. More new skeleton samples from the same population are needed to confirm this presumption.