This list, 2018 in paleomalacology, is a list of new taxa of ammonites and other fossil cephalopods, as well as fossil gastropods, bivalves and other molluscs that were described during the year 2018, as well as other significant discoveries and events related to molluscan paleontology that occurred in the year 2018.
General research A study on the impact of the Paleocene–Eocene Thermal Maximum on the richness, turnover, or ecological structure of shallow marine molluscan faunas from the Gulf Coastal Plain, or on the body size, growth rate, or life span of component taxa, is published by Ivany et al. (2018). A study on the basal metabolic rate of Pliocene to recent bivalves and gastropods from the Western Atlantic is published by Strotz et al. (2018). A study evaluating how faithfully stratigraphic ranges of extant Adriatic molluscs are recorded in a series of cores drilled through alluvial, coastal and shallow-marine strata of the Po Plain (Italy) is published by Nawrot et al. (2018), who also evaluate the implications of their study for interpretations of the timing, duration and ecological selectivity of mass extinction events in general.
Ammonites
Research A study on the life history and habits of ammonites as indicated by measurements of their conchs is published by Walton & Korn (2018). A study on the life mode of ammonite hatchlings, as indicated by the oxygen and carbon isotope composition of the embryonic shells and early postembryonic whorls of five juveniles of Hoploscaphites comprimus from the Fox Hills Formation (South Dakota, United States), is published by Linzmeier et al. (2018). A study on the succession of latest Permian ammonite fossils in Iran is published by Kiessling et al. (2018), who interpret their findings as indicating that Permian–Triassic extinction event had a prelude leading to extinction pulses, a decline of body size and morphological simplification in latest Permian ammonites. A study on the distribution and abundance of Early Triassic ammonites from the western United States basin is published by Jattiot et al. (2018). A study testing whether the Rapoport effect can be observed among the early Pliensbachian ammonites from the area of the present-day Europe, the Middle East and North Africa is published by Zacaï et al. (2018). A study on the number of eggs laid by large adult females of Cretaceous ammonites and belemnites, as well as on the ecological niches occupied by juvenile ammonites and belemnites, is published by Tajika, Nützel & Klug (2018). Ammonite nuclei (earliest whorls), representing a rare case of preservation of very early ontogenetic stages of ammonites and indicating high juvenile mortality that is seldom recorded in the fossil record of this group, are described from the Cretaceous (upper Turonian to Coniacian) of Tanzania by Ifrim, Wendler & Lehmann (2018), who interpret their finding as indicating that the mating and spawning areas of ammonites were locally restricted, and that their earliest ontogenetic stages were probably distributed by currents passing by their mating and spawning areas, similar to extant coleoids. A study on the paleoecology of the ammonites belonging to the genera Baculites and Scaphites, as indicated by the intracolonial variance in the size of zooids of cheilostome bryozoans that colonized the internal body chambers of the shells of these ammonites once they settled to the seafloor following the death of the ammonite, is published by Berry (2018). A study on the growth of spines in Kimmeridgian aspidoceratids, Turonian euomphaloceratines and Coniacian collignoniceratids is published by Ifrim, Bengtson & Schweigert (2018). A study on the suture lines in Cretaceous ammonite genera and on the link between suture complexity and generic longevity in ammonites is published by Pérez-Claros & Bengtson (2018). A study on the ammonite turnover events during the broad 'mid-Cretaceous' interval is published by Bengtson & Kakabadze (2018). A sclerochronological study of shell material from seep and age-equivalent non-seep specimens of Baculites compressus, aiming to test the hypothesis that methane seeps provided a habitat for ammonites, is published by Landman et al. (2018).
New taxa