[1] We present data on the temporal distribution of planktonic foraminifer genotypes (small subunit (SSU) ribosomal (r) RNA gene) and morphospecies (sediment traps) collected during 1999 in the Santa Barbara Channel. The sampling was undertaken with special emphasis on paleoceanographically important morphospecies, predominantly Globigerina bulloides. We found the same genotype of G. bulloides (type IId) in all the changing hydrographic regimes associated with this region throughout the annual cycle with the exception of January, when we recorded the additional presence of the high-latitude G. bulloides type IIa. We identified three new genotypes: Neogloboquadrina dutertrei type Ic, N. pachyderma dextral type II, and Turborotalita quinqueloba type IId. Our data suggest that G. bulloides type IId and possibly even the new genotypes listed above may be associated specifically with the complex hydrography or other environmental features characteristic of this area. Since G. bulloides type IId occurs throughout the year and its peak fluxes are related to different hydrographic regimes, we argue that the physical properties of the water column are not the major factor influencing the distribution and growth of this genotype. In sediment trap samples we found a skewed coiling ratio for G. bulloides (most likely representing type IId), which is related neither to sea surface temperature nor to genotypic difference. This study illustrates the necessity to map both the spatial and temporal distribution of the genetic types, especially in areas of paleoceanographic interest, where geochemical and paleontological proxies are being calibrated.

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A high degree of intraspecific variation, both genetic and in shell morphology, of the operculate land snail Cyclophorus fulguratus (Pfeiffer, 1854) suggests that its classification as a single species warrants reconsideration. We sequenced two nuclear (18S and 28S) and two mitochondrial (16S and COI) genes of 46 C. fulguratus specimens and used them to estimate the phylogeny and to determine the validity of species boundaries. Molecular phylogenetic analyses revealed the presence of three lineages corresponding to three geographically disjunctive populations of C. fulguratus in Thailand. Likelihood tests of topologies significantly supported the non-monophyly of the C. fulguratus–complex and Bayesian species delimitation analysis significantly supported the potential representation as distinct species of these three lineages. Discriminant function analysis based on geometric-morphometrics of shell shape allowed for significant distinction of these three candidate species, although they revealed a considerable degree of overlap of shell shape reflecting their crypsis morphologically. The diagnostic characters are provided by color pattern, pattern of protoconch and pattern of jaw. In conclusion, the results support that the C. fulguratus s.l., as currently recognized, consists of three distinct species in Thailand: C. fulguratus s.s., C. rangunensis and C. abditus sp.nov., which are described herein.

Recent conceptual and practical advances in phylogenetic species delimitation have enabled progressively robust biodiversity studies. Delimiting species in widespread taxa is an intriguing problem; the edible operculated land snail Cyclophorus volvulus (Müller, 1774) is a good example since it shows a high degree of shell and color variation along with a widespread distribution throughout Thailand. Taxonomic boundaries for C . volvulus were examined and clarified using a combined morphological and phylogenetic approach, the latter of which was based on both nuclear and mitochondrial gene sequences. Moreover, three species delimitation analyses were applied: Poisson tree processes (PTP), automatic barcode gap discovery (ABGD), and generalized mixed Yule-coalescent (GMYC). All phylogenetic trees revealed that C . volvulus was polyphyletic and comprised of three clades that coincided with their geographic distribution. The three species delimitation analyses concurred with the phylogenies and formed at least three groups. According to the results, C . volvulus s.l., as currently recognized, consists of three distinct species in Thailand: C . volvulus s.s., C . occultus sp. nov., and C . borealis sp. nov., which are described herein. Moreover, several of these highly distinct C . volvulus evolutionarily significant units (ESU) are likely to require urgent conservation attention.

The radiation of Partula land snails has produced a large array of distinct morphological, ecological and behavioural types occupying many tropical volcanic islands in the Pacific Ocean. Within the Society Islands of French Polynesia, the mode of evolution is thought to have involved a single colonization event on each island, with later speciation occurring largely in situ. The present study examines genetic variation in the mitochondrial cytochrome b gene among taxa within the Society Island archipelago. Levels of intraspecific variation are found to be high, but variation among species is sometimes small. Mitochondrial variants do not always cluster according to island and some species are found to be polyphyletic in the cytochrome b tree, despite other morphological and molecular evidence that strongly supports their monophyly. A possible explanation for the polyphyly of species is that different variants are derived from ancestral mitochondrial polymorphisms that have been retained despite speciation events. Although it is possible that there has been some gene flow among islands, the distribution of mitochondrial lineages across islands strongly indicates that their origins predate the colonization of the islands in the study, and that they are very unlikely to have evolved entirely in situ.