Published data on initial chamber (protoconch) diameter in 507 species, and embryonic shell (ammonitella) diameter in 231 species of Ammonoidea, and embryonic shell (nauta) diameters for 132 species of coiled Nautiloidea, were used to examine evolutionary change in ectocochleate cephalopod reproductive strategies. Palaeotemperatures were found to be a key factor influencing historical changes in the evolution of egg size in ammonoids and nautiloids. A negative relationship was found between egg size and warming of the Earth's climate. Factors related to habitat were also important; in general egg size was larger in cold-water cephalopods. Egg size in Lytoceratina and Phylloceratina in the deep waters of the upper continental slope was much larger than in epipelagic Scaphitidae, as in modern fish and squids. Small eggs and high evolutionary rates helped ammonoids to colonise new habitats and develop high biological diversity, but involved them in planktonic food webs making them more vulnerable to abiotic variability (e.g., climatic changes), ultimately leading to their extinction. Large eggs helped nautiloids to persist through geological history, but at the cost of lower biological diversity, lower evolutionary rates and restricted options for colonising new habitats. Large-egged species such as nautiloids are more vulnerable to ecological, biotic disasters such as the appearance of new predators, including modern fishery. Independence from the planktonic food web is likely to be very important for a taxon's long-term survival over evolutionary history, as demonstrated also by Coelacanthiformes and Elasmobranchia. • Key words: Ammonoidea, Nautiloidea, reproductive strategy, mass extinction, climate change, egg. Vladimir V. Laptikhovsky, Falkland Islands Government Fisheries Department, Stanley, FIQQ 1ZZ, Falkland Islands; vlaptikhovsky@fisheries.gov.fk • Mikhail A. Rogov, Geological Institute of Russian Academy of Sciences, Pyzhevskii Lane 7, Moscow, 119017, Russia; russianjurassic@gmail.com • Svetlana V. Nikolaeva, Paleontological Institute, Russian Academy of Sciences, Moscow, 117997, Russia; 44svnikov@mail.ru • Alexander I. Arkhipkin, Falkland Islands Government Fisheries Department, Stanley, FIQQ 1ZZ, Falkland Islands; aarkhipkin@fisheries.gov.fk Reproductive strategy is an important choice that species face continuously during their evolutionary history. A trade-off exists between fecundity and egg size (numbers vs "quality" of hatchling) because generative production in every species is restricted by body size, available food and longevity (Kasyanov 1999). Understanding these competing strategies led to the idea of r-and K-selection in life histories (MacArthur & Wilson 1967, Pianka 1970. It involves a bet-hedging concept that assumes that maximizing strategies are more advantageous in stable and predictable environments where variance is minimal, while minimizing strategies can enhance long-term fitness in periodically variable environments. Because of this, r-populations tend to inhabit unpredicta...

The oegopsid squid family Onychoteuthidae was recently revised based on morphology, but sufficient material for a complementary molecular analysis has not been available until now. In the present study, over 250 sequences of cytochrome c oxidase subunit I (COI) and 16S rRNA for 222 individuals were analysed to create a combined phylogeny for the family. Results support monophyly for the family and all seven onychoteuthid genera (including Moroteuthopsis, established herein as the senior genus name for species formerly attributed to Kondakovia); 29 genetically distinct species were recovered, with the BIN (Barcode Index Number) analysis for COI showing good congruence overall with morphological species groupings. No sequences were available for five additional known species, making the total family diversity likely to exceed 34 species. Seven of the BINs formed in this study appear to represent undescribed taxa, suggesting that even in this relatively well-studied family, much additional work remains before a comprehensive understanding of the diversity and evolutionary relationships for the Onychoteuthidae can be achieved.

The veined squid, Loligo forbesii Steenstrup, 1856, occurs at the European Shelf areas including the Azores and represents a valuable resource for the European commercial fishery in the North East Atlantic. However, very little is known about its population structure and phylogeography. This lack of knowledge also impedes the development of sustainable fishery management for this species. The present study combined the use of two types of markers that retrieve patterns of gene flow in different time spans; the analysis of 16 nuclear microsatellites and sequencing of the mitochondrial cytochrome oxidase subunit I (COI). Whereas the high mutation rate of microsatellites allows the description of recent patterns of connectivity in species, the lower mutation rate of COI provides phylogeographic patterns on a longer timescale. A total of 347 individuals of L. forbesii were investigated from nearly the entire distribution range of the species, including the North East Atlantic Shelf, the Azores and the Mediterranean. Individuals from the Western and Eastern Mediterranean Sea have never been included in a genetic study before. We were able to analyse COI sequences from all 12 sampling areas and define three clades of L. forbesii. Due to our large sampling area, we are presenting 13 COI-haplotypes that were previously unknown. The microsatellite analysis does not include the Azores but three main clades could be identified at the remaining 11 sampling sites. Low FST values indicate gene flow over large geographical distances. However, the genetically significant differences and an additional slight grouping in the microsatellite structure reveal that geographical barriers seem to influence the population structure and reduce gene flow. Furthermore, both markers provide strong evidence that the observed phylogeographic pattern reflects the geographical history of the Azores and the Mediterranean Sea.

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