The effects of crowding on the survival and growth of neonatal Biomphalaria glabrata were studied in petri dish cultures containing artificial spring water (ASW) and the filamentous cyanobacteria Nostoc sp. To study the effects of a reduced volume of ASW on a fixed number of neonatals, 25 snails were cultured in either 200, 40, or 15 mL of ASW for up to 22 days. The growth of neonatals in 200 mL of ASW was significantly greater (analysis of variance, P<0.05) than that of snails maintained in either 40 or 15 mL ASW at 10. 17, and 22 days postcultivation. The percent survival by day 22 was 76% for neonatals in 200 mL of ASW, 56% for those in 40 mL of ASW, and 32% for neonatals in IS mL of ASW. To study the effects of varying the number of snails in a constant volume of ASW, 70 or 30 neonatals were maintained in petri dish cultures each containing 200 mL of ASW. There was a significant increase in snail growth in the culture with 30 neonates compared to that with 70 snails at 10 and 18 days postcultivation. The percent of surviving snails at 18 days in the culture with 30 snails was 97% compared to 72% in the culture with 70 neonates. The results of our study showed that a reduction in the volume of ASW on a fixed number of neonates and an increase in the number of neonates in a fixed volume of ASW adversely affected the growth and survival of neonatal B. glabrous.
The Pacific slope of North America's Cretaceous to late Eocene record of the pteriid bivalve Pteria Scopoli, 1777 is studied in detail for the first time. It is mostly represented by Pteria pellucida (Gabb, 1864) and Pteria clarki (Weaver & Palmer, 1922), which are redescribed and refined in their stratigraphic distributions. Pteria pellucida, known from southwestern Oregon and California, was previously reported ambiguously as being both Cretaceous and Eocene age but is actually restricted to the Late Cretaceous (early Turonian to late Santonian). Pteria clarki ranges in age from middle to middle late Eocene. It was previously reported as occurring only in Washington State but also occurs in California. Other species are Pteria lochi, sp. nov., of late late Campanian to possibly early Maastrichtian in age, and Pteria sp., of late Paleocene age; both are found in California. The definition of Pteria is expanded based on the presence of weak radial ribs on P. load sp. nov. The so-called Pteria bowel Nelson, 1925, from southern California and of late Paleocene age, has a hinge similar to that found in bakevelliids. Phelopteria Stephenson, 1952 is recognized for the first time as a junior synonym of Pteria. Specimens of the studied species were collected from shallow-marine, fine-grained siliciclastics that accumulated under warm-temperate conditions during the Late Cretaceous and under subtropical conditions during the Paleogene. Specimens are rare, except at a few localities. Pteria most likely originated during the Jurassic in the Old World Tethys Sea region. It arrived in the study area during the early Turonian, which coincided with the highest sea-level stand and the warmest waters of the Late Cretaceous.
In 1977, the marine limpet taxonomic concept Lottia digitalis was discovered to encompass a northern and a southern species whose geographic ranges overlapped on the California coast between Point Conception and the southern limit of Monterey Bay. In 2008, a geographic survey was performed to reestablish the species' zone of sympatry and to confirm the partitioning of their primary microhabitats. In the three decades between surveys, the southern species, L. austrodigitalis, has advanced its northern limit to Bodega Head, and L. digitalis has kept its southern limit at Point Conception. In the northern part of their new zone of sympatry, the two species approach complete partitioning of shared microhabitats at lour sites spanning two degrees latitude, with L. atistrodigitalis predominating on high intertidal rock faces and L. digitalis on Pollicipes payments colonies. A model of allopatric speciation with a role for ecomorphs is proposed that could account for the evolution of diversity among the western North American Lottiidae.
The horizontal, vertical, and seasonal distribution patterns: size structure; maturity; feeding activity: and life cycle of the deep-water pelagic gonatid squid Gonatopsis octopedatus Sasaki, 1920 are described based on data collected during 25 research cruises in the Sea of Okhotsk and northwestern Pacific Ocean. This species was rather common in the Sea of Okhotsk and occurred occasionally in the Pacific Ocean. It was distributed mainly beyond the continental shelf between 0 and 1300 m depth. The largest aggregations of squid occurred in the deep southern basin in the Sea of Okhotsk. The highest abundance was observed in summer, when small young squid dominated the catches. In autumn and winter, growing squid descended down to the mesopelagic zone, where adult and maturing squid dominated the catches. Dorsal mantle lengths ranged from 28 mm (early juveniles) to 163 mm (mature adults). Analyses of seasonal changes in size structure, sexual maturity, and vertical distribution suggest that. in the Sea of Okhotsk, spawning occurred from the late summer through winter at great depths, and early life stages appear in the pelagic zone from winter through summer. Assuming that females brood their eggs in an egg mass between their arms (as do some other gonatids), and that the embryonic period lasts about a year, the estimated life cycle is about 2 yr for males and 3 yr for females.
Trimusculus reticulatus (Sowerby) is an air-breathing, limpet-like, pulmonate gastropod inhabiting the intertidal zone of the northeastern Pacific Ocean, from California to Washington. Although many distributional records are reported for this relatively common species, little has been published on its internal anatomy, which is also true for other Trimusculus species. The external morphology and internal anatomy of Trimusculus volt-Wows are described. Scanning electron microscopy pictures of anatomical parts of Trimusculus are presented here for the first time. The anatomy of Trimusculus reticulatus is compared with other Trimusculus species. The need for a systematic revision of Trimusculus is discussed.
Mollusks comprise diverse taxa that provide crucial ecological links in coastal marine habitats. These organisms are highly sensitive to the environment around them and thus any changes can greatly affect molluscan species diversity. Gracilaria salicoruia (C. Agardh) E.Y. Dawson, 1954 is an invasive alga species in Hawaii, which has become prevalent in many coastal marine ecosystems. Its interactions with native species are not well documented. In this study, we investigated the relationship between abundance of G. solicoruia and benthic nearshore molluscan species abundance and diversity. Three levels of G. salicornia abundance (low, intermediate, high) were surveyed at two sites in Hilo, Hawaii Island. Each site was sampled five times. The total abundance of mollusks was highest in the area of low G. salicornia abundance, but there was no significant difference. The total number of mollusk species was significantly higher in the area of high G. salicornia abundance. The fact that more mollusk species occupy the area of high G. salicornia abundance suggests that this invasive species of alga does have a positive effect on species diversity in at least some taxa.
The facelinid genus Phyllodesmium (Ehrenberg, 1831) consists of approximately 24 described species that prey upon soft-bodied corals. At least five additional species have yet to be described, making it an interesting genus for testing phylogenetic hypotheses. The genus is extremely morphologically diverse, with many species adapting specifically to a specific host coral. One of the most interesting adaptations found in this genus is the widespread participation in a symbiotic relationship with photosynthetic dinoflagellates in the genus Symbiodinium. Two new species, Phyllodesnium acanthorhimm n. sp. and Phyllode.smium undulation n. sp.. from the Philippine Islands and Japan are described, and a morphological phylogcny is created to include the two new species, as well as three undescribed species. An examination of the PhyMA/emu/um phylogcny suggests that species with digestive gland branching and zooxanthellae are more derived. Confidence and robustness in this analysis are lacking, however, and further studies using molecular data could add confidence to this conclusion.
Several methods have been proposed to "clean" the soft tissues of molluscs of mucus, so that the surface cilia can be examined microscopically. We report the first empirical test of the effectiveness of methods for removing mucus in the pallial cavity surface of chitons. Three methods were compared, at several time intervals: the enzyme hyaluronidase, the mucolytic agent N-acetyl cysteinc (NAC), and seawater washing via the natural action of cilia in excised tissue. Treatment in NAC for 10 min produced the best results, and we recommend this protocol as a starting point for further investigation on mucus removal in a broader suite of taxa. We present the first description of the pallial surface cilia in the chiton 1,Lepidochitona cinera. During the course of this study, we also determined that these chitons were frequently infested with a ciliate protozoan parasite, Trichodina sp., which have been historically reported from chitons but never studied in detail. The parasites were absent where antimucus treatments were effective, but their abundance and large size (about 30-mu m diameter) in less successful treatments obscured the view of the pallial cavity surface.
A new species of Harpa, H. daisyae is described from the Upper Miocene Cercado Formation of the Dominican Republic. The genus in the tropical American Neogene is discussed, phylogenetic groups within the genus are suggested, and paleobiogeographic implications commented.
Three new species of aeolid nudibranchs are described and another species is redescribed and redesignated based on specimens collected at several localities of the tropical eastern and lndopacific. Dondice galaxiana sp. nov. is a facelinid aeolid, distinct from other species for its light brown and cream colored body with four dark brown spots containing bright turquoise centers between each cluster of cerata and a few similar spots on the sides. The cerata are light brown or pinkish tan with white cnidosacs and a brown ring below the cnidosacs. They are in raised arch-shaped clusters. The mottled brown and cream oral tentacles are long, the short rhinophores have disk-shaped annulations, and the unarmed penis has a prominent penial gland. The generic placement of another facelinid species was problematic and was therefore assigned as a new genus, Adfacelina gen. nov. Adfacelina medinai sp. nov. has cerata in arches with multiple rows. The penis is blunt tipped, bearing one outer row of tiny conical spines and there is no accessory gland. The external coloration is pink with opaque yellow blotches covering the body, cerata, rhinophores, and oral tentacles. Our phylogenetic analysis suggests this genus is close to the genera Dondice and Facelina. Phestilla hakunamatata Ortea, Caballer & Espinoza, 2003, is redescribed and placed in the facelinid genus Hermosita because it has a cleioproctic anal position, a radula with slender denticles, two bursae, and a fleshy papilla beside the penis. Both the familial and generic placement of the fourth species was problematic. It has the external appearance and notal flange of a flabellinid and the anus is acleioproctic. Internally it has a unidentate radula and the penis is armed with a chitinous spine. External coloration of Unidentia angelvaldesi sp. nov. varies with diet from orange shades or white with a series of purple lines and opaque white markings on the body, rhinophores, cerata, and oral tentacles. A phylogenetic analysis suggests that this species should be placed in a new genus, Unidentia gen. nov., and that this genus is more closely allied to other uniseriate, acleioproctic aeolids of the genus Piseinotecus than members of the family Facelinidae.
We immersed southern pygmy squid, Idiosepius notoides Berry 1921 (hereafter squid), in three anesthetics (cold seawater, magnesium chloride [MgCl2], and ethanol [EtOH]). Anesthesia was important for inducing both immobility and body transparency, conditions that were required for measuring extracellular lipid droplets. Cold anesthesia (4 degrees C, day 1) led to frequent inking and some mortality. The MgCl2 treatment (1-5%, day 18) did not induce body transparency and was often lethal. The 2% EtOH anesthesia (12-15 degrees C, days 1-12) was most successful: it induced no inking and was followed by 100% recovery and postanesthetic survival (>7 days). There was no difference in induction times for squid anesthetized on day 1 versus day 2 after collection, with loss of body color patterns in similar to 12 sec followed by loss of mobility at similar to 30 sec. Time to immobility was related to time to transparency. Size (dorsal mantle length) was not related to time to induction or recovery. Although all squid survived three anesthesias with 2% EtOH, third inductions were significantly slower than first inductions. Anesthesia greatly improved accuracy of locating, counting, and measuring lipid droplets. With sublethal anesthesia, we detected extracellular lipid droplets in the digestive system of all 42 freshly collected squid. Without anesthesia, we failed to see cecal droplets in 20 of 41 squid that had them, and we failed to see digestive gland droplets in five of 23 squid that had them. Light EtOH anesthesia, including repeated treatments, did not seem to move droplets between the digestive cecum and the digestive gland or to induce expulsion of these droplets from the digestive tract.
Many invertebrates, including the mollusks, have been researched as potential source of compounds with antibiotic activity. Biochemical profile of the mucus from the slug Phyllocaulis boraceiensis was studied to determine if this species presents any fraction containing this sort of compound. Assays to quantify lipids, proteins, or peptides, free glucose or associated with other substances, were performed through establishment of the electrophoretic profile, high-performance liquid chromatography (HPLC), and mass spectrometry. The data were: lipids = 6.9 x 10(-5) mg/mL; protein = 1.15 x 10(-4) mg/mL; few amino acids were detected, probably because the molecules degraded; free glucose = not detected; glucose in association with other substance = 600 mu g/mL. In the HPLC assay, some bands of protein were detected correlating with the electrophoretic profile. The mass spectrometry showed a major proteic component of 17.5 kDa molecular weight. Any direct bactericidal or bacteriostatic effect was detected facing distinct bacteria of medical interest such as Escherichia colt and Staphylococcus aureus. It could be hypothesized that eventual active compounds are masked in the mucosal matrix of the secretion. Probably the P. boraceiensis mucus acts as a physical barrier, hindering the entrance of microorganisms in the body, does not act on the microorganisms assayed-or even does not present microbicidal property.
Akera bullata is the only member of the Anaspidea to produce lecithotrophic larvae that settle in response to a variety of different substrata.
Paradoris adamsae sp. nov. is described based on three specimens collected in Bocas del Toro, on the Caribbean coast of Panama. The new species is clearly a member of Paradoris because of the presence of a jaw with three plates, a narrow radula, a grooved outer edge of the lateral tooth hook, and grooved oral tentacles. It differs from other members of the genus by having a relative large body size, brownish body color, small rhinophores, and high rounded tubercles on the mantle. This is the second record of the genus Paradoris in the western Atlantic, where Paradoris mulciber has been reported from Brazil, Costa Rica, and the Caribbean Sea. A phylogenetic analysis including 25 taxa shows that Paradoris is monophyletic and divided into two main clades, one containing all tropical eastern Pacific, tropical Atlantic, and Mediterranean species, which is sister to a clade composed of tropical and temperate Indo-Pacific species. In the Indo-Pacific clade, three taxa from the southern temperate seas are sisters to the rest of the Indo-Pacific species. According to the present phylogenetic hypothesis, P. adamsae sp. nov. is more close related to Paradoris lopezi Hermosillo & Valdes, 2004, from the tropical eastern Pacific than to P. mulciber, from the western Atlantic. The present phylogeny is similar in several regards to hypotheses proposed for other groups of opisthobranchs and other marine organisms and suggests that the same major vicariant events had affected the biogeography of these groups. As a result of the present study at least 16 distinct species can be recognized in Paradoris, more than the double the number of valid species cited in the last revision of the genus.
The presence and density of gastropods, and the individual growth rate of Chilina fluminea snails at Rio de la Plata beach, Berisso, Buenos Aires province, Argentina, were analyzed to obtain population data about hosts that could be useful for control of the free-swimming larval stages (cercariae). Chilina fluminea has a unique annual reproductive period during winter, whereas other gastropods inhabiting the same area reproduce one to three. times a year, but never in winter. Thus, autumn, the season before reproduction and oviposition, is the most adequate season for taking actions to regulate the size of C. fluminea populations to reduce possible cases of human schistosomic dermatitis.
The presence of the extinct buccinid genus Amarophos in the tropical American Caribbean Neogene is reviewed with the description of two new Lower Pliocene species: Amarophos woodringi nov. sp. from the Shark Hole Point Formation of the Bocas del Toro region, Panama; and Amarophos arayaensis nov. sp. from the Aramina Formation of the Araya Peninsula, Venezuela. These new records extend both the previously known geographical and geological distribution of the genus.
We report field experiments of the diets of certain Gymnodoris species (Nudibranchia: Doridina: Gymnodorididae) that inhabit the seas in the vicinity of Japan. Of 21 individuals of five predatory species, 13 fed on 14 of the 44 prey individuals. Among these predators, five individuals of four species located the mucus trail of their prey and pursued it. After touching the prey with their oral tentacles, most predators everted the buccal apparatus to capture the prey. Two modes of feeding occurred: biting off part of the prey or swallowing it whole. Some predator and prey combinations have not previously been reported, to our knowledge: Gymnodoris alba fed on Vayssierea felis (Nudibranchia: Doridina: Vayssiereidae), and G. okinawae fed on Metaruncina setoensis (Cephalaspidea: Runcinidae). We also found an unknown gymnodorid that fed on several Elysia spp. and Thuridilla vatae. The unknown predator was similar in morphology to G. alba, but its prey items were similar to those of G. okinawae.
This study includes detailed morphological examination of 16 species of Philine to reconstruct a phylogenetic hypothesis of relationships within the Philinidae. Our purpose is to test the monophyly of a complex of species that closely resemble the type species, Philine aperta (Linnaeus, 1767). Our cladistic analysis of Philine supports both the monophyly of the genus and of a subclade of the Philine aperta clade. This P. aperta subclade consists of highly derived species that serve as poor models for understanding plesiomorphic attributes within the genus Philine and also within the family Philinidae; aspects of their morphology are too highly modified to provide appropriate exemplars of evolution of the entire clade. The systematics of this subclade has long been confused because of only subtle, but consistent, differences between species. Consequently, species have been synonymized and separated repeatedly. We found several characters of systematic importance that had not been used previously, including microstructure of the gizzard plates, fine details of the penial papilla, and branching of the prostate complex. We describe each of the taxa in the P. aperta clade that we examined, including the first detailed description of Philine orientalis A. Adams, 1854, and the first anatomical description of Philine elegans Bergh, 1905. We also describe four new species in the Philine aperta clade: Philine fenestra sp. nov., Philine paucipapillata sp. nov., Philine puka sp. nov., and Philine sarcophaga sp. nov. Specimens identified as Phallic. orientalis A. Adams, 1854 from Hong Kong (Morton & Chiu, 1990) and Cambodia (present study) are morphologically distinct from those found elsewhere (present study) and represent a distinct species described here as P. paucipapillata sp. nov. Lastly, we redescribe Philine alba Mattox, 1958, from California and differentiate it from the specimens of P. alba from several localities in the Western Atlantic described by Marcus & Marcus (1967) and Marcus (1974). We erect the name P. alboides sp. nov. for the Marcuses' specimens.
Dark submarine caves are unique habitats from which most coastal species are excluded because of darkness, marked oligotrophy, and reduced water circulation. Many bivalves have been found in caves of tropical West Pacific coral reefs, but nearly all reported species are very small in adult shell size, generally < 5 mm in length. Glossocardia obesa (Reeve, 1843) is an exceptionally large bivalve in the cave fauna and grows to 80 mm in adult shell length. Since live specimens of G. obesa are apparently very uncommon, there has been no study on its life-history traits. We performed an oxygen isotope analysis of a G. obesa (72 mm in shell length) collected alive in a submarine cave at Okinawa Islands, Japan. The delta O-18 record is divided into early- and late-growth phases. There is no systematic change in delta O-18 value in the early-growth phase, whereas the delta O-18 record for the late-growth phase contains six cycles. Comparing ihe delta O-18-derived temperatures from G. obesa with water-temperature records and delta O-18 value of seawater in the cave shows that the delta O-18 cycles of G. obesa reflect seasonal variation in water temperature. This result demonstrate; that the oxygen isotope analysis can usefully be employed to estimate growth and age in this species.
The Cenozoic fossil record of the vesicomyid bivalve genus Adulomya in Japan is evaluated. Five of the nominal species are confirmed based on shell morphology, hinge dentition, and the shape of the pallial line. Two of these are new to science: Adulomya hamuroi sp. nov. from the uppermost lower or lowest middle Miocene Higashibessho Formation in Honshu, and Adulomya kuroiwaensis sp. nov. from the uppermost middle or lowest upper Miocene Ogaya Formation in Honshu. A well-preserved specimen of Adulomya uchimuraensis, the type species of Adulomya, shows that this species lacks a pallial sinus and has an elongate ovate posterior adductor muscle scar. We redescribe Adulomya chitanii based on well-preserved, newly collected material. The identity of specimens previously assigned to the latter two species is outlined. Adulomya appears to have dispersed during the early Miocene from western North America along the North Pacific continental slope to Japan. It is present with five species in early and middle Miocene strata of Japan and shows a steep decline in diversity through the late Miocene and Pliocene. This decline coincides with, and may thus be linked to, the appearance and diversification of the vesicomyid genera Archivesica and Calyptogena from the late Miocene onwards. In the waters around Japan today, species of Adulomya live in deeper water than other vesicomyids and might thus have followed the onshore-offshore trend as suggested for other members of the vent and seep fauna.
