The social behavior of a marmoset (Saguinus fuscicollis) group III. Spatial analysis of social structure.

The social behavior, and particularly the spacing patterns, of a marmoset (Saguinus fuscicollis) group in a semi-naturalistic enclosure were observed for 14 months. Data analysis revealed various changes as the group grew in size from four to eventually six members. Weekly mean distances between the adult pair supported a spatial measure for estrus for the female. Group dispersion, mean squared distance between all possible pairs, seemed to vary with the age composition of the group. Factor analysis of location correlation matrices by 4-week blocks resulted in age-related subgroupings. Each of the adult pair formed an independent subgroup except for behavioral estrus and early infant care periods when they formed one subgroup. The offspring, initially attached to the adults, gradually moved into juvenile/subadult subgroups. Increasing spatial independence was shown as an animal approached adulthood at 24 months of age.     

The structure,meiotic behaviour and effects of B chromosomes in Briza humilis Bieb. (Gramineae)

A single population of Briza humilis contained two types of B chromosome, one a large (B^L) and the other a small (B^S) acrocentric. DNA measurements show that the B^L chromosome contains approximately twice as much DNA per unit length as the members of the regular complement. The meiotic pairing behaviour of the Bs is variable and B^L and B^S are seen to pair in some cells. The presence of B^L depresses the chiasma frequency of the regular complement but the chiasma frequency of A and B chromosomes does not appear to be related. The transmission rate of the B chromosomes is variable and the B^L shows a non-disjunction mechanism during microsporogenesis that is absent during megasporogenesis. For the B^S chromosome the transmission rate is very low and there is no evidence of a non-disjunction mechanism. In general seeds containing B^L chromosomes germinate more slowly than those without B chromosomes.     

Pseudoplacentela smirnovi gen. et sp. n. (Tunicata, Ascidiacea), with a discussion of its phylogenetic relationships

Pseudoplacentela smirnovi gen. et sp. n., a colonial ascidian from the Kuril Islands, is described and placed in the holozoidac. The related species Placentela crystallina Redikorzev also seems to belong to the Holozoidae rather than to the Polyclinidae.     

Regression equations to predict segmental moments of inertia from anthropometric measurements: an extension of the data of Chandler et al. (1975)

A set of regression equations was developed to fully utilize the data of Chandler et al. (AMRL Technical Report 74-137, Wright-Patterson Air Force Base, 1975) to estimate segmental moments of inertia in living subjects. Using anthropometric measurements as predictors, moments of inertia can be computed about both transverse and longitudinal axes passing through each segment's center of mass. Symmetry about segment long axes is assumed. Because of the small sample size upon which these equations are based, it is suggested that they be used cautiously, especially to avoid extrapolation to subjects having anthropometric measurements outside the range of sample values.     

Sarsicopia polaris gen. et sp.n., the first platycopioida (Copepoda: Crustacea) from the Arctic Ocean,and its phylogenetic significance

A new genus of Platycopioida is described from a boxcore sample taken at a depth of 534 m in the ArcticBarents Sea. This is the deepest record ofPlatycopioida so far. Sarsicopia gen. n. is thesistergroup of a taxon comprising Platycopia and Nanocopia; the sistergroup ofthese is Antrisocopia. Sarsicopia gen. n.is the only platycopioid to retain 2 inner setae onthe second endopod segment P2–P4, and 8 setae in thethird endopod segment of P2. The male antennnule isremarkable in having a geniculation located betweenancestral segments XX and XXI. It is suggested thatthis flexure zone was already present in thegroundpattern of Copepoda. Platycopia and Nanocopia have secondarily lost thisgeniculation.     

Population structure of an endemic vulnerable species, the Jamaican boa (Epicrates subflavus)

The Jamaican boa (Epicrates subflavus; also called Yellow boa) is an endemic species whose natural populations greatly and constantly declined since the late 19th century, mainly because of predation by introduced species, human persecution, and habitat destruction. In-situ conservation of the Jamaican boa is seriously hindered by the lack of information on demographic and ecological parameters as well as by a poor understanding of the population structure and species distribution in the wild. Here, using nine nuclear microsatellite loci and a fragment of the mitochondrial cytochrome b gene from 87 wild-born individuals, we present the first molecular genetic analyses focusing on the diversity and structure of the natural populations of the Jamaican boa. A model-based clustering analysis of multilocus microsatellite genotypes identifies three groups that are also significantly differentiated on the basis of F-statistics. Similarly, haplotypic network reconstruction methods applied on the cytochrome b haplotypes isolated here identify two well-differentiated haplogroups separated by four to six fixed mutations. Bayesian and metaGA analyses of the mitochondrial data set combined with sequences from other Boidae species indicate that rooting of the haplotypic network occurs most likely between the two defined haplogroups. Both analyses (based on nuclear and mitochondrial markers) underline an Eastern vs. (Western + Central) pattern of differentiation in agreement with geological data and patterns of differentiation uncovered in other vertebrate and invertebrate Jamaican species. Our results provide important insights for improving management of ex-situ captive populations and for guiding the development of proper in-situ species survival and habitat management plans for this spectacular, yet poorly known and vulnerable, snake.     

Range extension of the predatory cladoceranBythotrephes longimanus Leydig 1860 (Crustacea,Onychopoda) in Western Europe

The long-spined waterfleaBythotrephes longimanus Leydig 1860 (Crustacea, Onychopoda), a predatory cladoceran, new for the Belgian fauna, has been recorded in the water storage reservoir Broechem. Several possible methods of entry ofB. longimanus into lakes far outside its known distribution area are discussed.