Chronology, time averaging, and oxygen isotope composition of harvested marine mollusk assemblages from Ifri Oudadane, northeast Morocco

The archaeological site of Ifri Oudadane, NE Morocco, contains well-preserved marine mollusk concentrations throughout the Epipaleolithic (hunting-gathering) and Neolithic (food production) cultural phases, useful to test hypotheses driving such transition. However, the chronology and stratigraphy of harvested shells is complex due to the confluence of human activity and natural deposition processes. This work first quantifies the age and degree of time averaging of archaeological shells and then estimates sea-surface temperatures (SSTs) from the oxygen isotopes of selected specimens. Thirty-four radiocarbon-dated shells exhibited significant time averaging between 310 to 1170 yr that could not be explained by analytical error alone. This finding illustrates the need for individually dating shells in future paleoclimate investigations aiming for high temporal resolution. Nine isotopically analyzed shells dated to the Neolithic phase, between 5700 and 7600 cal yr BP, indicate that assuming constant oxygen isotopes of seawater, SSTs remained consistently warm, between 20°C and 22°C, that is, 2°C–4°C warmer than today. Results point to warmer conditions during the Neolithic, supporting the hypothesis that the rise of a food production mode of life in NE Morocco could have in part been triggered by warming conditions following the colder 8.2 event.

Mitochondrial genomes of two Polydora (Spionidae) species provide further evidence that mitochondrial architecture in the Sedentaria (Annelida) is not conserved

Contrary to the early evidence, which indicated that the mitochondrial architecture in one of the two major annelida clades, Sedentaria, is relatively conserved, a handful of relatively recent studies found evidence that some species exhibit elevated rates of mitochondrial architecture evolution. We sequenced complete mitogenomes belonging to two congeneric shell-boring Spionidae species that cause considerable economic losses in the commercial marine mollusk aquaculture: Polydora brevipalpa and Polydora websteri. The two mitogenomes exhibited very similar architecture. In comparison to other sedentarians, they exhibited some standard features, including all genes encoded on the same strand, uncommon but not unique duplicated trnM gene, as well as a number of unique features. Their comparatively large size (17,673 bp) can be attributed to four non-coding regions larger than 500 bp. We identified an unusually large (putative) overlap of 14 bases between nad2 and cox1 genes in both species. Importantly, the two species exhibited completely rearranged gene orders in comparison to all other available mitogenomes. Along with Serpulidae and Sabellidae, Polydora is the third identified sedentarian lineage that exhibits disproportionally elevated rates of mitogenomic architecture rearrangements. Selection analyses indicate that these three lineages also exhibited relaxed purifying selection pressures.

Biological Control of Pest Non-Marine Molluscs: A Pacific Perspective on Risks to Non-Target Organisms

Classic biological control of pest non-marine mollusks has a long history of disastrous outcomes, and despite claims to the contrary, few advances have been made to ensure that contemporary biocontrol efforts targeting mollusks are safe and effective. For more than half a century, malacologists have warned of the dangers in applying practices developed in the field of insect biological control, where biocontrol agents are often highly host-specific, to the use of generalist predators and parasites against non-marine mollusk pests. Unfortunately, many of the lessons that should have been learned from these failed biocontrol programs have not been rigorously applied to contemporary efforts. Here, we briefly review the failures of past non-marine mollusk biocontrol efforts in the Pacific islands and their adverse environmental impacts that continue to reverberate across ecosystems. We highlight the fact that none of these past programs has ever been demonstrated to be effective against targeted species, and at least two (the snails Euglandina spp. and the flatworm Platydemus manokwari) are implicated in the extinction of hundreds of snail species endemic to Pacific islands. We also highlight other recent efforts, including the proposed use of sarcophagid flies and nematodes in the genus Phasmarhabditis, that clearly illustrate the false claims that past bad practices are not being repeated. We are not making the claim that biocontrol programs can never be safe and effective. Instead, we hope that in highlighting the need for robust controls, clear and measurable definitions of success, and a broader understanding of ecosystem level interactions within a rigorous scientific framework are all necessary before claims of success can be made by biocontrol advocates. Without such amendments to contemporary biocontrol programs, it will be impossible to avoid repeating the failures of non-marine mollusk biocontrol programs to date.

Middle Miocene Conoidea (Neogastropoda) assemblage of Letkés (Hungary), Part II. (Borsoniidae, Cochlespiridae, Clavatulidae, Turridae, Fusiturridae)

Five conoidean families (Borsoniidae, Cochlespiridae, Clavatulidae, Turridae, Fusiturridae) are described from the early Badenian (early Middle Miocene) gastropod assemblage of Letkés (N Pannonian Basin, Hungary). The clayey sand deposits of the locality represent the Pécsszabolcs Member of the Lajta Limestone Formation, and contain the richest Badenian fossil marine mollusk assemblage of Hungary. 41 conoidean species are recorded and illustrated; Clavatula hirmetzli n. sp., Clavatula santhai n. sp., Clavatula szekelyhidiae n. sp., Perrona harzhauseri n. sp. and Perrona nemethi n. sp. are described as new for science. Clavatula nogradensis Csepreghy-Meznerics, 1953 is a junior synonym of Clavatula granulatocincta (Münster in Goldfuss, 1841), Clavatula (Surcula) krenneri Csepreghy-Meznerics, 1953 is a junior synonym of Fusiturris emiliae (Hoernes & Auinger, 1891), Clavatula (Surcula) nodosa borsodensis Csepreghy-Meznerics, 1969 is a junior synonym of Clavatula orientoromana Báldi, 1960. New combinations: Acamptogenotia praecedens (Bellardi, 1877) nov. comb., Perrona letkesensis (Csepreghy-Meznerics, 1953) nov. comb., Fusiturris emiliae (Hoernes & Auinger, 1891) nov. comb., Fusiturris intermedia (Bronn, 1831) nov. comb., Fusiturris reevei (Bellardi, 1847) nov. comb.