Mollusks are considered ideal systems for understanding combined defensive strategies as evolutionary or local phenotypical responses to numerous predators with distinct attack modes. Despite the growing knowledge of morphological and physiological defensive mechanisms, studies on behavioral adaptations among shelled mollusks, especially among terrestrial gastropods, are still astonishingly scarce. The present study records and describes mechanical and presumably defensive behavior in two species of Simpulopsidae, Leiostracus perlucidus and Simpulopsis cf. tryoni, in the Atlantic Rainforest biome in southeastern Brazil. These behaviors are similar between the two species but differ slightly probably because of differences in body and shell shape.
The complete mitochondrial genome of Voluta musica, the type species of the type genus of the family Volutidae, was determined using Illumina sequencing and found to be a double stranded circular molecule 15,306 base pairs in length with a GC content of 37.2%. It contains 13 protein-coding genes, 2 ribosomal RNA genes, and 22 tRNA genes with the same gene order and strand orientation as in most neogastropods, including all Volutidae, for which mitogenomes have been determined. The potential origin of replication is located in a 62-bp non-coding region between tRNA-Phe and the gene for COX3. Phylogenetic analyses using maximum likelihood and Bayesian inference with nucleotide sequences of all protein coding and ribosomal genes show Voluta musica to be most closely related to Fulgoraria rupestris, support the monophyly of Volutidae, and contradict the inclusion of Cancellariidae within Volutoidea.
An earlier molecular phylogeny of the rapanine muricid genus Acanthais Vermeij and Kool, 1994 indicated that this tropical American group contains two morphologically distinct taxa, one comprising the type species together with a fossil precursor, and the other comprising two Recent eastern Pacific and one Miocene Caribbean species. Despite the molecular results, I propose the new genus Penethais for this second group, with type species Purpura triangularis de Blainville, 1832. Penethais differs from Acanthais by having a lower spire, broader and rounder aperture, and the absence of a columellar fold, adapical notch in the outer lip, and labral tooth. Both groups are Paciphilic, surviving only in the eastern Pacific. I also refine an earlier account of the distribution of columellar folds in the Rapaninae and in its sister taxon, the subfamily Ergalataxinae.
Otostomus is a monotypic and poorly known genus Bulimulidae genus. Only parts of the reproductive system and hard parts are known for Otostomus signatus. The present study goals are, first, to redescribe O. signatus through a detailed investigation of shell features, including microornamentation and ultrastructure, radula and jaw, and detailed anatomical data of its pallial cavity and associated organs, digestive, reproductive, and nervous systems. We also compare the morphology of the species with closely related bulimulids to assess if the phylogenetic relationships recently proposed in a molecular study are supported by morphology. Otostomus signatus is characterized by a conical shell sculptured by thick growth lines, with a truncate-ovate aperture, expanded peristome with three teeth, odontophore retractor muscle ramifying two times, the first in two almost symmetrical muscles, and the second in 4-5 closely attached pack of fibers, intestinal loop absent, imbricated radula, radular formula (9-(31)-1-(31)-9), ovotestis with several thin, tightly squeezed, digitiform ramifications leading to a compact seamless irregular shape, almost symmetrical nervous ring, cerebral ganglia completely fused, without commissure, posterior ganglia completely fused, single large statocyst inside the posterior ganglia. Otostomus signatus shares more similarities in both hard and soft parts with Cochlorina than with Bulimulus, supporting recent molecular phylogenies.
Despite their species being fairly common throughout the world's oceans, the genus Diplodonta is one of the least under stood. Exact taxonomic placement has been problematic for more than a century and it does not appear that this will be resolved anytime soon. Diplodonta enenkionensis is a new spe cies described from the sublittoral zone, off the western coast line of Wake Atoll (Pacific Ocean). It is the first Ungulinidae to be recorded from this remote location, and the smallest known species of Diplodonta.
The small cold-water carditid genus Miodontiscus includes Miodontiscus prolongatus (Carpenter, 1864), M. annakensis (Oinomikado, 1938), and M. popovi new species. Miodontiscus prolongatus differs from M. annakensis by having a less inflated shell with strongly prosogyrate umbones and strongly arcuated posteior margin, a bifid anteior cardinal tooth in the right valve, fewer radial ribs (8-13; 12-19 in M. annakensis). Miodontiscus popovi new species can be distinguished from M. annakensis by having a larger shell, a bifid anterior cardinal tooth on left valve and more (19-24) radial ribs that are flat-topped. Of these, M. prolongatus first appeared in the Middle to Late Miocene of Kamchatka and spread southward to California and Japan by the Late Miocene cooling. Miodontiscus annakensis first appeared in the Late Miocene in central Honshu. In the Late Pliocene to Early Pleistocene, both species widely occurred from the Japan Sea borderland of Hokkaido and Honshu to Jeju Island. Miodontiscus popovi new species has no fossil records and is confined to the Russian side of the Japan Sea and Kurile Islands. It has became clear that M. annakensis rears juveniles in the inner demibranch (maximum 34 embyos in a female at the shell size of 7.9 mm) and its mature size is estimated to be about 5 mm in length. Moreover, we suggest that it may be spawning throughout the year.
The calyptraphorine stromboid, Aulacodiscus lissoni (Douville, 1921), found in northern Peru in bioclastic sandstones of the lower Eocene Basal Salina Formation, is notable for its complete envelopment by calluses, including massive left-lateral callus knobs. Previous shell descriptions suffered from the absence of the anterior end. Newly reported specimens reveal an outer lip with a well-formed posterior notch and a short anterior spine, both unique to calyptraphorines. A suite of characters ( inter alia, an extended posterior canal, notched outer lip, and dorsal callus knob) indicate A . lissoni burrowed just below the sediment surface in an environment where exhumation and overturning by waves or predators were a constant risk; more than half of the specimens exhibit ventral traces of predation that were likely lethal. The calyptraphorine taxon most similar to A . lissoni, the thickly callused Paleocene Veatchia carolinae (Maury, 1912), inhabited sandy carbonate platforms in Senegal, Trinidad, and Colombia. A calyptraphorine phylogeny that would include both thickly callused species is precluded at present by the scarcity and incompleteness of specimens of V . carolinae and the geographically and temporally isolated occurrence of A . lissoni in the eastern Pacific Ocean.
A survey of heterobranch sea slug diversity in the Bocas del Toro Archipelago documented a total of 20 species of Anaspidea, Cephalaspidea, Nudibranchia, and Pleurobranchomorpha during an 81-hour search effort. This includes four new records for Bocas del Toro in addition to a potentially undescribed species and an unidentified species. Both direct and indirect collecting methods were used. Species were identified and photographed in the lab, and most are illustrated herein. The present paper constitutes the most updated study of sea slug diversity in the Bocas del Toro Archipelago.
Oxychona M & ouml;rch, 1852 is an understudied genus of Bulimulidae Tryon, 1867, with eight species, of which only two are known beyond shell features: the type-species Oxychona bifasciata (Burrow, 1815) (reproductive system and hard parts) and Oxychona michelinae Porto, et al ., 2016 (radula). The present study goals are, first, to redescribe Oxychona lonchostoma (Menke, 1828) through a detailed investigation of shell features, including microornamentation and ultrastructure, radula and jaw, and detailed anatomical data of its pallial cavity and associated organs, digestive, reproductive, and nervous systems. We also compare the morphology of the species with closely related bulimulids to assess which of the phylogenetic relationships proposed for the genus in the literature is better supported by morphology. Oxychona lonchostoma is characterized by a conical shell with a large spire angle, triangular aperture, long and narrow pallial cavity, intestinal loop absent, radular formula (13-(27)-1-(27)-13), ovotestis beige with several digitiform ramifications, symmetrical nervous ring, cerebral ganglia completely fused, without commissure, posterior ganglia completely fused, single and large statocyst inside posterior ganglion. The morphology described supported relationships previously established only with characters of the reproductive system, but did not support those found when molecular data are included, suggesting that anatomies of these mollusks should be investigated together with molecular phylogenies, to reach more robust integrated hypotheses.
Two new species of Late Cretaceous cypraeoideans are described. Protocypraea raymondgrahami n.sp. is from upper-most Santonian strata of the upper Haslam Formation, near Brannen Lake, Nanaimo District, Vancouver Island, British Columbia and Eocypraea? carolehickmanae n.sp. is from the Cenomanian Osburger Gulch Sandstone Member of the Hornbrook Formation, Bellinger Hill, Jackson County, southwestern Oregon.
Profundiconus motirohivanus new species is described from material collected in deep water at Sala y G & oacute;mez Ridge (Motu Motiro Hiva), Nazca Ridge, and other nearby localities off Chile. The new species has been previously misidentified as Profundiconussmirna (Bartsch and Rehder, 1943). It is com-pared to other related species of Profundiconus. Part of the sea-mounts where the new species has been collected are within the newly created offshore Motu Motiro Hiva Marine Park. Infor-mation on potentially unique and endemic species, such as the one presented here, is relevant for the implementation of properly informed management measures in this poorly explored area
The molluscan invertebrate paleontology community has lost one of its most prominent members as LouElla Saul [ne & eacute;Rankin] passed away on June 21(st), 2021. Her specialty was Cre-taceous and Paleogene mollusks of the Pacific slope of North America from British Columbia, Canada to Baja California, Mexico. She described and/or co-authored 289 molluscan taxa including 90 bivalves, 198 gastropods, one cephalopod. Seven-teen taxa were named in her honor. Included herein is her com-plete bibliography, list of taxa described by her and co-authors, and a list of molluscan taxa named in her honor.
Falsuszafrona yucatecana a new species from relatively deep water in the southwestern Gulf of Mexico, has an elongate- fusiform shell with a multispiral protoconch, is pale yellowish- tan in coloration with a network of lighter, ocellated markings, has uneven axial and spiral sculpture and an inner labrum without denticles. It is described and compared with other Falsuszafrona from the western Atlantic.
Three new records of Bathysciadium pacificum Dall, 1908 from off Oregon and Washington extend the range of the species from Peru by similar to 7,300 km to the temperate northeastern Pacific. The preserved and relaxed animal shows that the mantle extensions are not sensory papillae, but mantle folds forming the periostracum rays on the shell. Examination of radula, mantle, and mantle cavity by scanning electron microscopy (SEM), including environmental SEM (ESEM) of the fluid-preserved animal, adds a novel dimension to the understanding of the anatomy of these rare deep-sea snails. ESEM is a suitable tool for fine morphological investigations of rare natural history specimens. The monotypic genera Bathypelta Moskalev, 1971 and Bonus Moskalev, 1973 are re-synonymized under Bathysciadium Dautzenberg and H. Fischer, 1900. No mineralization of the radula was detected by SEM-Energy Dispersive Spectroscopy (EDS/EDAX) mapping
A new species of Trigonulina is described from material recov-ered during benthic fisheries surveys carried out off South Carolina in the 1980s and 1990s. It is compared with T. ornata d'Orbigny, 1853, the only other named Recent member of the genus recorded in the Western Atlantic, and with relevant fossil taxa. The morphological range of T. ornata is considerable, and its lectotype and a series of variants are figured. The distinctive shell microsculpture is illustrated in detail
Members of the genus Polycera Cuvier, 1816 occur world-wide, but to date few species have been recorded from Chinese waters. In the present study, we describe a new species of Polyc-era based on specimens collected from the intertidal zone of Xiamen, China. Polycera lini new species had been previously already recorded from Chinese waters but was misidentified as Polycera fujitai Baba, 1937. Morphologically, Polycera lini new species can be clearly separated by its external coloration from all other congeners, including Polycera fujitai. Phylogenetic analyses of two mitochondrial (COI and 16S rRNA) and one nuclear (H3) gene using Bayesian inference, maximum likeli-hood, and species delimitation analysis (ASAP) also support the separation of Polyceralini new species from its congeners.
A new species of microsnail in the genus Paravitrea was discov-ered while sampling leaf litter invertebrates in western North Carolina. The new species is smaller and has fewer whorls than most Paravitrea species. It is also unique in having only a single nodular lamella in young juveniles, rather than one to several axial rows of nodular lamellae as in most other Paravitrea spe-cies. Its adult shell is similar only to that of Paravitrea blarina, from which it differs by the absence of nodular lamellae on the shell. To facilitate comparisons between these two species, the reproductive anatomy of P. blarina is presented for the first time, showing significant differences from the new species. The new species appears to be closely associated with the Broad River, which may play a role in its unusual distribution in the Piedmont Plateau.
The group of Drupa R & ouml;ding, 1798 (Muricidae: Rapaninae) comprises thirteen Recent Indo-West Pacific reef-associated gastropod species. Based on a previously published molecular phylogeny of the group and on a detailed examination of shell morphology, I propose to divide this group into four genera: Drupa; Ricinula Schumacher, 1817; Sistrum Monfort, 1810; and Amplidrupa new genus (type species: Purpura clathrataLamarck, 1816). The new genus differs from Drupa and Sis-trum by the broader aperture, undivided adult outer-lip den-ticles, and the possession of a downward-projecting inner-lip extension on the adaxial side of the siphonal notch. It differs from Ricinella by the presence of a central columellar fold, among other characters. All genera have a broad distribution with several examples of peripheral speciation. Columellar folds may be plesiomorphic in Rapaninae.
A new species of Pen Shell, Pinna (Subitopinna) evexa new species, is described from material collected in Indonesia and elsewhere in Southeast Asia. Comparison is made with related taxa from the Indo-Pacific region. The new species is apparently widely distributed and present in many collections under incorrect identifications. The problem of using older names that are based on single specimens to identify morphologically plastic taxa is discussed.
Live and fresh dead specimens of Naria turdus, a species with a native range in the Red Sea and the western Indian Ocean, were found in shallow water off the island of Aruba in the south-western Atlantic. The most plausible pathways for the invasion of the species are considered to be the transport of larvae in ballast waters of a cargo ship, or attachment of the egg capsules to the cargo ship hull. A combination of juvenile, young adult, and fully mature specimens was observed, suggesting a new, well-established, and possibly breeding population of N. turdus in the western Atlantic.
