Molluscan

Wunderpus photogenicus n. gen. and n. sp. is a spectacular long-armed species that occurs on soft sediment habitats in shallow waters (typically less than 20 m deep) in Indo-Malayan waters. It is characterized by small eyes on elongate stalks, a long, conical papilla over each eye and a dramatic and fixed color pattern of white bars and spots over a

The resolution of higher level phylogeny of the coleoid cephalopods (octopuses, squids, and cuttlefishes) has been hindered by homoplasy among morphological characters in conjunction with a very poor fossil record. Initial molecular studies, based primarily on small fragments of single mitochondrial genes, have produced little resolution of the deep relationships amongst coleoid cephalopod families. The present study investigated this issue using 3415 base pairs (bp) from three nuclear genes (octopine dehydrogenase, pax-6, and rhodopsin) and three mitochondrial genes (12S rDNA, 16S rDNA, and cytochrome oxidase I) from a total of 35 species (including representatives of each of the higher level taxa). Bayesian analyses were conducted on mitochondrial and nuclear genes separately and also all six genes together. Separate analyses were conducted with the data partitioned by gene, codon/rDNA, gene+codon/rDNA or not partitioned at all. In the majority of analyses partitioning the data by...

The behavioural ecology of terrestrial molluscs is poorly known. We consider the
behavioural ecology of three morphologically similar, parapatric camaenids of southeast
Australia: Meridolum corneovirens, Meridolum middenense, and Pommerhelix duralensis.
We critically review available literature on their behaviour and address knowledge gaps
through field and laboratory studies, including spool-line tracking data for P. duralensis and M. corneovirens. These data are supplemented by in situ observation for each species

Significant differences remain between gastropod phylogenetic hypotheses based on morphological and molecular datasets. We collected additional data from three gene segments (28S rDNA expansion region D1 (36 taxa plus two from GenBank), cytochrome c oxidase subunit 1 (35 species plus one from Genbank) and small nuclear RNA U2 (24 species)). These were combined with data available for the same species for histone H3 and two other segments of 28S rDNA. Analyses of these data using cladistic, maximum likelihood or Bayesian methodologies were conducted in an attempt to resolve some of the differences between current hypotheses of gastropod relationships based on morphological and molecular data. The results were of particular interest in four areas. (1) Patellogastropoda in most analyses are included in a derived clade with some Vetigastropoda. In an analysis with Nautilus as the sole outgroup, transversions weighted threefold as costly as transitions and, with third codon position data...

ABSTRACT Variations in progesterone (P4) and testosterone (T) levels in the gonad of Octopus maya from Sisal in Yucatan State, Mexico, were investigated by radioimmunoassays and in relation to four gonad maturation stages (GMS) and to the reproductive cycle, as represented by two maturity indices (microscopic ‘MiMI’ and macroscopic ‘MaMI’). According to the GMS and the maturity indices, the reproductive season of O. maya from Yucatan occurred from February to June. In females, P4 and T displayed the same pattern, with a tendency to increase at the same time, although on average, P4 had seven-fold higher concentrations than T. In contrast, P4 and T in male gonads displayed a different pattern, where T concentrations were relatively stable throughout all of the study months. In the female gonad P4 was lowest (close to 0 pg g–1) during both developing (GMS-I) and maturing (GMS-II) stages, and increased (189 ± 53 pg g–1) approaching the mature stage (GMS-III) to a maximum value of 611 pg g–1. Concentrations of T in the male gonad were lowest (106 ± 9 pg g–1) during the maturing stage (GMS-II) and increased up to the mature stage (GMS-III), reaching a maximum of 440 pg g–1. Pearson's correlation (r) between hormones and maturity indices showed strong relationships for females (around 0.4 and −0.7; p < 0.05), but there were negligible or weak relationships for males (0.2 and −0.1; p > 0.05). Hormone correlations in females were inverse with MaMI and direct with MiMI. Our major findings showed that gonadal P4 levels were elevated during GMS-III and GMS-IV (i.e. periods of vitellogenic oocytes), where the characteristic aspect is an ovary with very high oocyte diameters, with the primary follicle cells deeply infolded in the ooplasm for yolk synthesis. These results suggested a synchrony between P4 and the process of folliculogenesis, and in turn, vitellogenesis.