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Gastropods from the family Eulimidae have different life strategies in inhabiting their host echinoderms, but it is currently assumed that they derive most of their nutrition from the host's tissues. This paper presents the results of stable carbon and nitrogen isotope analyses of different tissues of echinoderm hosts (crinoids Comaster nobilis and holothurians Holothuria atra) and their ectosymbionts (Annulobalcis wareni and Peasistilifer nitidula). Our data show that the stable nitrogen isotope enrichment level in symbionts is practically indistinguishable from that of their hosts. The symbionts are depleted in 13C compared to their hosts. We suggest that these molluscs may not feed on host tissues but instead obtain food particles from the environment, possibly stealing detritus particles, which, in turn, are food for these species of echinoderms. We revealed the proximity of the location and slight overlap of the crinoids' visceral tissue and their symbiont tissues. This suggests a greater food variety for the symbionts. The detected differences in δ13C values and the almost complete absence of overlap of the holothurians' body walls and symbionts allow us to conclude that in this symbiotic association, the hosts and symbionts rely on different food sources. In addition, the two studied echinoderm species differed significantly in δ13C signatures, which is confirmed by their different lifestyles. Thus, stable isotope analysis suggests that kleptoparasitism is at least an additional and possibly exclusive feeding mode for eulimids A. wareni and P. nitidula. However, this hypothesis will need to be followed up with morphological, biochemical, and experimental data. [ABSTRACT FROM AUTHOR]

As part of a study on holothurians from the southern Gulf of Mexico, some Holothuria mexicana Ludwig, 1875 were obtained for gut analysis. In two of them, a couple of eulimids were located inside the main tube of the respiratory tree. They were identified as Megadenus holothuricola Rosén, 1910, described from the Bahamas Islands, based on five specimens attached to the respiratory tree of H. mexicana. The original description was brief with few details, the type material is lost, and the species has not been found again. In this contribution, this species is confirmed for Campeche Bay, Mexico. The adult shell is globular to conical, transparent, thin, and fragile. Megadenus smithi sp. nov. from Palmyra Atoll, Central Pacific is described based on adult specimens. It differs from its congeneric species in its more robust shell, the pseudopallium does not cover the shell, and its short and contracted proboscis forms a thick disc. Further research on these eulimid parasites is now complicated in the southern Gulf of Mexico because of the holothurian population collapse due to over-exploitation of the fishery. [ABSTRACT FROM AUTHOR]

This study presents new records for 4 eulimid species (Gastropoda, Eulimidae) including Melanella eburnea (Megerle von Mühlfeld, 1824), Melanella hypsela (Verrill & Bush, 1900), Melanella sp., and Eulimostraca encalada Espinosa, Ortea & Magaña, 2006 found on the body wall of the sea cucumber Holothuria mexicana in Belize. Three of these records (M. hypsela, M. eburnea, and E. encalada) represent a first for the Western Caribbean ecoregion and close a distributional gap for these species in the Caribbean. The geographic distribution of M. eburnea is thereby expanded by ~800 km; M. hypsela by ~1,200 km and E. encalada by ~970 km in the Tropical Northwestern Atlantic province. This article presents for the first time H. mexicana as a new host record for E. encalada. [ABSTRACT FROM AUTHOR]

Fusceulima Laseron, 1 955 and Halielloides Bouchet & Warén, 1986 are reported from the southwestern Atlantic for the first time. Halielloides ingolfiana Bouchet & Warén, 1 986 is considered a valid name, and the taxon is distinct from its previous senior synonym Eulima verrilliana Bush, 1909 in shell shape and absence of an umbilicus. Fusceulima saturata sp. nov. is characterized by a conical shell, domed at the apex, a short ovoid aperture, and a distinct dark-brown spiral band near the suture. Fusceulima toffee sp. nov. also has a conical shell and a dome-shaped apex, but has a taller high aperture and the entire shell is dark brown. Halielloides cf. ingolfiana, Fusceulima cf. boscheineni, and Fusceulima cf. minuta, are here recorded from the continental shelf off southeastern Brazil. The nominal species of these taxa were originally described from the northeastern Atlantic. Their status remains dubious because of lack of information on their biology, anatomy and molecular data. Regarding shell morphology, we cannot distinguish the Brazilian specimens from species in the northeastern Atlantic with the material available. A series of short grooves close to the suture of the protoconch in all species of Fusceulima, including the type species Fusceulima jacksonensis Laseron, 1 955, is a possible diagnostic character for this genus. [ABSTRACT FROM AUTHOR]

The gastropod family Eulimidae has attracted considerable attention as one of the most diverse groups of parasitic molluscs in terms of number of species and ranges of body plans and parasitic strategies. However, the phylogenetic position of the family has not been established within the Hypsogastropoda and this has hampered the inference of ancestral states in the evolution of the morphology and parasitic strategies. Here we present Bayesian and maximum likelihood phylograms of Hypsogastropoda based on nuclear and mitochondrial loci (18S and 28S rRNA, Histone H3, COI and 16S rRNA) and a better taxonomic sampling than in previous molecular analyses, to determine the position of Eulimidae. The resulting trees suggest Vanikoridae as the sister group of Eulimidae; the two families are collectively placed in the newly redefined superfamily Vanikoroidea, with Truncatelloidea and (potentially paraphyletic) Rissooidea as closest relatives. Vanikorids are protandrous hermaphrodites as are many eulimids and are essentially carnivorous, differing from the mostly gonochoristic and herbivorous/detritivorous Truncatelloidea and Rissooidea. The mode of feeding may have a phylogenetic signal also within Eulimidae, where radula-less species constitute a robust clade. Other new findings include a close affinity of the submarine-cave Pickworthiidae to Cerithioidea and a terminal position of Nystiellidae within the paraphyletic Epitoniidae. [ABSTRACT FROM AUTHOR]

Abstract: The new combined attachment and feeding trace fossil Oichnus halo isp. n. is described from oral surfaces of Campanian and Danian Echinocorys tests. It shows striking conformity with traces produced by Recent eulimid gastropods of the genus Thyca parasitising the asteroid Linckia laevigata. The trace is characterised by a central penetration surrounded by the eponymous circular groove. The occurrence of Oichnus halo isp. n. in the Campanian is contemporaneous with the first appearance of eulimid gastropods in the fossil record and indicates that the eulimid–echinoderm parasitic interaction was already established in the Late Cretaceous. [Copyright &y& Elsevier]

The current article provides the first record of Annulobalcis aurisflamma Simone and Martins, 1995 outside São Paulo state, Brazil. Herein we extend its geographical distribution to northeastern Brazil. [ABSTRACT FROM AUTHOR]