![Coralliophila (s.1.) renatimagnei d'apr~s Magne 1941 [x 0,95].](https://www.researchgate.net/profile/Philippe-Renard-3/publication/285569493/figure/fig2/AS:669420099735555@1536613597084/Coralliophila-s1-renatimagnei-daprs-Magne-1941-x-0-95_Q320.jpg)
![Leptoconchus duvergieri, Meilhan (Vives), Miocene inf~rieur (Aquitanien): 1-3: H-12,8 mm; 4-5: H= 11 mm; 6-7; H= 11,7 ram; 8 Leptoconchus dans le corail Thegioastraea [x 2,9]. 1-8. Leptoconchus duvergieri, Meilhan (Vires), Lower Miocene (Aquitanian): 1-3: H= 12,8 ram; 4-5: H= 11 ram; 6-7; H= 11,7 ram; 8 Leptoconchus in the coral Thegioastraea [x 2,9]. ce-type Magilus antiquus MONTFORT, 1810, par d~signation originale, Indo-Ouest-Pacifique) par l'absence de tube prolongeant l'ouverture. Leptoconchus a v~cu dans les mers europ~ennes jusqu'au Miocene moyen. En effet, le Magilus rollei (BOETTGER, 1906) (=? Magilus jaegeri (BOETTGER,](https://www.researchgate.net/profile/Philippe-Renard-3/publication/285569493/figure/fig3/AS:669420099751945@1536613597126/1-8-Leptoconchus-duvergieri-Meilhan-Vives-Miocene-infrieur-Aquitanien-1-3_Q320.jpg)
![Galeropsis lavenayanus, d'apr~s les figures de Hup~, 1864 [x 1,4]. 4-5. Galeropsis madreporarus, 4, "Oc~anie" (sans autre precision) H= 34ram; 5, ~le Maurice, coll. Fischer (MNHN-Paris-Malacologie), H= 21 ram. 6-9. Galeropsis lavenayanus, Miocene inf~rieur (Aquitanien), Corbleu "Moulin de Carro", 6-7, coll. Gourgues, H= 22,4 ram; 8-9, leg. Favia & Senut (MNHN-Paris), H= 23 ram, 8, d~tail de la sculpture. 1-3. Galeropsis lavenayanus from Hup~, 1864 Ix 1,4]. 4-5. Galeropsis madreporarus, 4, "Oc~anie" (without indication) H= 34ram; 5, Mauritius island, H= 21 ram. 6-9. Galeropsis lavenayanus, Lower Miocene (Aquitanian), Corbleu "Moulin de Carro" 6-7, H= 22,4 mm; 8-9, H= 23 ram, 8, detail of the sculpture.](https://www.researchgate.net/profile/Philippe-Renard-3/publication/285569493/figure/fig4/AS:669420099756038@1536613597580/1-3-Galeropsis-lavenayanus-daprs-les-figures-de-Hup-1864-x-1-4-4-5-Galeropsis_Q320.jpg)
![Galeropsis lavenayanus; 1-4, leg Favia & Senut (MNHN-Paris), Corbleu "Moulin de Carro", Miocene inf~rieur (Aquitanien), 1-2: H= 26 mm, 3-4: H= 24,6 mm; 5-6, coll. Renard, St-Paul-L~s-Dax "Ma~not", Miocene inf~rieur (Aquitanien), Galeropsis encore attach~e ~ Pocillopora madreporacea, 5 [x 3,7], 6 Longueur = 112 ram. Sauf mention contraire tous les exemplaires proviennent de la collection Lozouet & Maestrati (MNHN-Paris-Malacologie). 1-6. Galeropsis ]avenayanus; 1-4, leg Favia & Senut (MNHN-Paris), Corbleu "Moulin de Carro", Lower Miocene (Aquitanian), 1-2: H= 26 ram, 3-4: H= 24,6 ram; 5-6, coll. Renard, St-PaulL~s-Dax "Marnot'; Lower Miocene (Aquitanian), Galeropsis still attached to its coral host Pocillopora madreporacea, 5 Ix 3, 7], 6 Lenght = 112 ram. Unless otherwise indicated all specimens are from Lozouet & Maestrati's collection..](https://www.researchgate.net/profile/Philippe-Renard-3/publication/285569493/figure/fig5/AS:669420099743763@1536613597866/1-6-Galeropsis-lavenayanus-1-4-leg-Favia-Senut-MNHN-Paris-Corbleu-Moulin-de_Q320.jpg)
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The Coralliophilidae, Gastropoda from the Oligocene and Lower Miocene of the Aquitaine (Southwestern France): Systematics and details of coral hosts
Abstract and Figures
Six species of Coralliophilidae and three genera (Coralllophila, Leptoconchus and Galeropsis) are recognised from the Oligocene and Lower Miocene of Aquitaine: Lower Oligocene (C. renatimagnei), Upper Oligocene (L. costatus, C. burgidalensis and C. sacyi) and Lower Miocene (L. costatus, L. duvergieri, C. burgidalensis, C. sacyi and G. lavenayanus). Coralliophila renatimagnei is the oldest member of the Coralliophilidae recorded from the European Cainozoic and also the earliest boring species of the family, having been found within the Cladocora corals (Faviidae). The evolution of a Coralliophilidae with a borer life-style is related to the development of modern coral reefs. The genus Leptoconchus is recorded for the first time from the European Cainozoic. Two species were collected from Thegioastraea corals (Faviidae). Leptoconchus costatus is known from the Upper Oligocene to the Lower Miocene (Lower Aquitanian) and gave rise to L. duvergieri (Upper Aquitanian). Biometric analysis suggests gradual evolutionary change from L. costatus to L. duvergieri. The older Galeropsis species (G. lavenayanus) is redescribed from the Lower Miocene (Aquitanian). This species was found still attached to its coral host, Pocillopora madreporacea (Pocilloporidae), thereby establishing an ancient association between Galeropsis and Pocillopora. Finally, it is shown that Quoyula IREDALE, 1915 is a synonym of Galeropsis HUPE, 1860.
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... These snails are typically parasitic on corals, feeding suctorially (Robertson 1970;Modica and Holford 2010). Coralliophiline species first appeared in the fossil record in the middle Eocene and were feeding on corals by the early Oligocene (Lozouet and Renard 1998;Vermeij and Carlson 2000). Their phylogeny has been relatively well investigated (e.g., Mariottini 2001a, 2001b;Massin and Dupont 2003;Gittenberger 2006;Oliverio et al. 2009;Gittenberger and Gittenberger 2011). ...
... We then assumed that the entire clade (including outgroup species) could not be older than the earliest Cenozoic (following Claremont et al. 2011), nor younger than the oldest known coralliophiline fossil (Middle Eocene, Clairbonian; 40.4-48.6 Ma; Lozouet and Renard 1998). ...
... Despite the ambiguity in the precise phylogenetic reconstruction of corallivory, this behaviour is restricted to Drupella and is therefore unlikely to have evolved before the origin of the genus. Corallivory therefore evolved later in Drupella than it did in the other coralfeeding muricids, the coralliophilines (by the early Oligocene; Lozouet and Renard 1998;Vermeij and Carlson 2000). Thus, in contrast to the coralliophilines, the origin of corallivory in Drupella does not seem to be connected with the appearance of the major coral groups in the Eocene (Wilson and Rosen 1998;Wood 1999;Crame and Rosen 2002;Wallace and Rosen 2006). ...
Although muricid gastropods in the genus Drupella are well-known consumers of Indo-Pacific corals, their evolutionary and ecological history is unclear, as is their relationship
to the apparently facultative coral-feeder Ergalatax margariticola, which has been reported to feed upon corals in Hong Kong. We use a well resolved molecular phylogeny (reconstructed from
one nuclear and two mitochondrial genes) to show that the monophyletic genus Drupella falls into the muricid subfamily Ergalataxinae and that the genus includes ‘E. margariticola’, which is composed of two cryptic species. We show that genetic structure within the here reassigned ‘Drupella margariticola’ species complex does not relate to feeding mode, but instead seems to correspond to broad patterns of habitat ecology found
in other gastropod taxa. Our analyses suggest that Drupella originated in the late Miocene (approximately 9.6Ma) and diversified approximately 5.0Ma, much later than the appearance
of modern coral reefs in the early Cenozoic. Thus, it is possible that corallivory in Drupella evolved in response to the major expansion and reorganization of reefs that took place in the early Miocene.
KeywordsMuricidae–Speciation–Coral feeding–Molecular phylogeny–
Ergalatax margariticola
... Coralliophilinae are known since the Late Cretaceous (Sohl 1964). Lozouet and Renard (1998) reported one of the oldest members boring in corals from the Oligocene of the Paris Basin. ...
Parasitism and similar life styles such as carnivorous grazing or mucus feeding without killing the prey are important in marine gastropods. Some of the most diverse living gastropod families have this feeding behavior. Taxonomic uniformitarianism is the most important tool to infer parasitism or similar life styles in fossil gastropods. The extant family groups in question (Eulimidae, Epitoniidae, Pyramidellidae, Architectonicidae, Coralliophilinae, Ovulidae, Cerithiopsidae and Triphoridae) originate mostly in the Late Cretaceous (Cerithiopsidae in the Middle Jurassic) and Paleocene. They are performing an ongoing adaptive radiation and some of the mentioned families belong to the most diverse gastropod groups forming a considerable part of marine ecosystems regarding species richness and relative abundance. At the same time, origination and radiation of the carnivorous, commonly predatory Neogastropoda took place. This points to a trophic revolution in Gastropoda that forms an important aspect of the Mesozoic Marine Revolution. Most modern parasitic gastropods are small, high-spired, show high diversity and low disparity within families and belong to Apogastropoda. By analogy, some extinct gastropod families which show the same properties might have lived parasitic too (e.g., Pseudozygopleuridae, Zygopleuridae, Meekospiridae, Donaldinidae). However, this will remain speculative to a large degree until direct host associations are found. Direct evidence for parasitism is exceptional with the Palaeozoic platyceratid/crinoid interaction being one of the best studied examples. In Gastropoda, functional shell morphology may help to identify parasitism in the fossil record but this field is scarcely studied.
I combined data from the taxonomy, phylogeny, functional morphology, biogeography, and fossil record of gastropods to probe the origins, distribution, and fates of predatory gastropod clades characterized by the presence of a labral tooth, a downwardly projecting tooth or spine formed at the edge of the outer lip of the shell. A labral tooth occurs in at least 608 species, of which 251 are Recent. Studies of the type and position of the labral tooth, along with other characters, indicate that the labral tooth has evolved independently at least 58 times, beginning in the Campanian epoch of the late Cretaceous. The labral tooth plays a more or less active part in predation on relatively large prey animals that are protected by a hard skeleton. In the Recent fauna, tooth-bearing species are overwhelmingly warm-temperate to tropical in distribution (240 of 251 species; 96%). Within Muricidae (excluding Coralliophilinae), however, there is no discernible latitudinal gradient in the number of tooth-bearing species relative to total regional diversity. First appearances of clades with a labral tooth are overwhelmingly concentrated in the late Oligocene to Pleistocene interval, with the largest number appearing during the early Miocene (12 clades). The temporal pattern differs significantly from that expected on the basis of the number of faunas available per time interval, and is therefore not an artifact of sampling or fossil preservation. The most consistent factor associated with, and permitting the repeated evolution of, the labral tooth is high planktonic primary productivity. Two factors may account for the link between primary productivity and the evolution of labral teeth: (1) the general economic opportunity afforded by ready availability of an access to nutrients, and (2) the greater abundance and sizes range of available suspension-feeding prey animals. Incumbency - the presence of already well-adapted species - often controls evolutionary opportunity. The complementary distributions of major tooth-bearing clades in many parts of the world point to the role of well-adapted incumbents in limiting the adaptive exploration by other clades that could in principle evolve a labral tooth. The elimination of incumbents by extinction, however, does not provide opportunities for other clades to fill the adaptive void.
Members of the neogastropod muricid subfamily Rapaninae are abundant, shallow-water predators whose phylogeny was previously investigated by Kool (1993b), who used mainly anatomical characters. In order to deepen understanding of the evolution of this important clade and to incorporate functional, ecological, and fossil evidence, we performed a phylogenetic analysis based on 34 shell characters in 45 genus-level taxa, including five muricid outgroups. Cladograms based on shell characters alone differed from those founded on anatomical features, and these analyses differed from the phylogenetic reconstruction combining all available morphological evidence. The preferred cladogram incorporates all evidence and reveals a “Thais group” and an “Ergalatax clade” that both emerge from the derived portion of a more primitive, paraphyletic group of other rapanines. The Ocenebrinae, the other four outgroup taxa, and three ergalataxine taxa all lie outside the rapanine clade that includes the remaining ergalataxines as a derived subclade. We used the phylogenetic results to probe aspects of the ecological history of the Rapaninae. Our data imply that antipredatory shell defenses (elongated aperture, denticles on the inner side of the outer lip, and robust external spines and tubercles) evolved multiple times, mainly in post–early Miocene clades in the Indo–West Pacific region. These results support earlier nonphylogenetic inferences. We compared known prey types and methods of predation of living rapanines with their distribution on our phylogenetic tree. The plesiomorphic mode of feeding in the Rapaninae is drilling of hard-shelled prey. Feeding by other means and on such soft-bodied prey as sipunculan and polychaete worms evolved several times independently among post–early Miocene rapanines in the Indo–West Pacific. Methods of predation on hard-shelled prey that involve edge-drilling or attack by way of the aperture also evolved independently several times, but did so throughout the geographical range of the subfamily. Specialization for life on the upper shore occurred in at least eight lineages, all but two of which are confined to the Indo–West Pacific. Ecological diversification of the Rapaninae was therefore most common in the tropical Indo–West Pacific during and after early Miocene time. This diversification occurred in a setting of already high biological diversity and intense competition and predation.
Fourteen species of Coralliophilinae (Neogastropoda, Muricidae) have been identified in the material collected by the MUSORSTOM 9 expedition to the Marquesas Islands. This coralliophiline fauna appears severely impoverished, compared to other West Pacific areas. At least half of the species (seven) are members of the shallow water fauna, an unusual pattern for the prevalently deep water coralliophilines, which may indicate an increase with depth of the effects of marginality on benthic faunas. One new species Coralliophila nukuhiva n. sp. is here described.
The twenty Recent species of the muricid subfamily Coralliophilinae known from the New Zealand region are recorded and illustrated. The following eight species are reported for the first time from New Zealand: Babelomurex nakamigawai (Kuroda, 1959), Coralliophila sp. aff. sertata, C. solutistoma Kuroda & Shikama in Shikama, 1966, Hirtomurex marshalli Oliverio, 2008, Latiaxis pilsbryi Hirase, 1908, Leptoconchus sp., Mipus matsumotoi Kosuge, 1985 and Rhizochilus sp. cf. antipathum Steenstrup, 1850. The species previously recorded as Neothais clathrata (A. Adams, 1854) from New Zealand is actually Coralliophila squamosissima (E.A. Smith, 1876). Two new species are described from bathyal depths: Hirtomurex tangaroa n. sp., and Hirtomurex taranui n. sp. Four species (Coralliophila sertata (Hedley, 1903), C. sp. aff. sertata, Hirtomurex tangaroa n. sp. and H. taranui n. sp.) are restricted to the South-West Pacific, with the latter three possibly endemic to the New Zealand region. All the New Zealand species have planktotrophic development, and 60% of them live in deep water. Copyright © 2009 Malacological Society of Australasia & Society for the study of Molluscan diversity.
Diversité des Coralliophilinae (Mollusca, Neogastropoda, Muricidae) des Îles Australes (Pacifique sud). Les Coralliophilinae sont une grande sous-famille de Muricidae, comprenant 200–250 espèces se nourrissant exclusivement d'anthozoaires. Le matériel récolté durant les expéditions BENTHAUS et RAPA 2002 aux Îles Australes est révisé. Vingt-huit espèces sont mentionnées dont une nouvelle, Coralliophila australis n. sp., qui se caractérise par sa grande taille et sa forme allongée. Toutes les espèces sauf une possèdent un développement planctotrophique, 10 espèces (36 %) proviennent d'eaux peu profondes et 15 espèces (54 %) d'eaux profondes. La proportion plus petite d'espèces de Coralliophilinae d'eaux profondes (comparée aux intervalles et à la moyenne à l'échelle globale) dans cette zone marginale du Pacifique, suggère que la marginalité peut affecter de manière plus importante les faunes d'eaux profondes que celles d'eaux peu profondes.
Biodiversity estimates through geologial times are difficult because of taphonomic perturbations that affect sedimentary records. Pristine shell assemblages, however, allow for calibration of past diversity. Diversity structures of two exceptionnally-preserved Miocene bivalve assemblages are quantitatively determined, compared with modern communities and used as paleoenvironmental proxy. The extremely rich assemblages were collected in Aquitanian (Early Miocne) carbonate sands of the Vives quarry (Meilhan, SW France). Original mineralogy, either calcitic or aragonitic, is well preserved. Among two samples more than 28.000 shells were counted and 135 species identified. Both paleontological and sedimentological data indicate a coral patch-reef environment. The two Vives assemblages have a similar diversity structure despite facies differences. Rarefaction curves display a steep slope up to ~600 shells and approach the honrizontal asymptote. The high values of PIE index suggest a fairly homogeneous shell distribution within the assemblages.
The fossil data are compared to death shell assemblages of a modern reefal setting (Touho area, New Caledonia), which is assumed to sample modern analogues of Meilhan paleoenvironments. Data of taxonomy and diversity structure of Miocene assemblages appear coherent with Recent faunas and in consequence highly suitable for calibration of fossil assemblages. The shape of the rarefaction curves and PIE indexes compare well to modern data, especially those of deep (>10 m water depth), sandy depositional environments found downward the reef slope. The similarity of the Vives samples (among them and with the Recent deep samples) mostly derives from transport and taphonomic processing. This assumption is supported by sedimentological and paleontological observations. The sample Vives 1 is interpreted as a proximal debris flow of coral reef-related sediments. The sample Vives 2 sample coral patch reef communities in a sand beach environment; transport likely derives from the joint effect of storm and tides. Sediment transports gather allochthonous and in situ materials leading to mixed assemblages with a high variety of ecological affinities (e.g. substrate). Such taphonomic processes are recorded in the diversity metrics.
The comparison of fossil assemblages with Recent analogues demonstrates that taxonomic richness and diversity structure can be well preserved in the fossil record and are simple parameters useful for an indirect reconstruction of paleoenvironments.
Aim Since the opening of the Suez Canal in 1869, many tropical taxa from the Indo‐West Pacific (IWP) realm have entered the Mediterranean Sea, which is experiencing rising temperatures. My aims are: (1) to compare biogeographically this tropical transformation of the Mediterranean biota with the tropical faunas of the Mediterranean and adjacent southern European and West African seas during the Late Oligocene to Pliocene interval; (2) to infer the relative contributions of the tropical eastern Atlantic and IWP to the tropical component of the marine biota in southern Europe; and (3) to understand why West Africa is not now a major source of warm‐water species.
Location Southern Europe, including the Mediterranean Sea, and the coast of tropical West Africa.
Methods I surveyed the literature on fossil and living shell‐bearing molluscs to infer the sources and fates of tropical subgenus‐level taxa living in southern Europe and West Africa during the Late Oligocene to Pliocene interval.
Results Ninety‐four taxa disappeared from the tropical eastern Atlantic (including the Mediterranean) but persisted elsewhere in the tropics, mainly in the IWP (81 taxa, 86%) and to a lesser extent in tropical America (36 taxa, 38%). Nine taxa inferred to have arrived in the tropical eastern Atlantic from the west after the Pliocene did not enter the Mediterranean. The modern West African fauna is today isolated from that of other parts of the marine tropics.
Main conclusions Taxa now entering the Mediterranean through the Suez Canal are re‐establishing a link with the IWP that last existed 16 million years ago. This IWP element, which evolved under oligotrophic conditions and under a regime of intense anti‐predatory selection, will continue to expand in the increasingly warm and increasingly oligotrophic Mediterranean. The IWP source fauna contrasts with the tropical West African biota, which evolved under productive conditions and in a regime of less anti‐predatory specialization. Until now, the post‐Pliocene West African source area has been isolated from the Mediterranean by cold upwelling. If further warming should reduce this barrier, as occurred during the productive and warm Early Pliocene, the Mediterranean could become a meeting place for two tropical faunas of contrasting source conditions.
The oldest freshwater neritiliid, Neritilia bisinuata, is described from the Middle Eocene of the Loire Basin. Another European species, N. neritinoides, ranging from the Lower Oligocene to Lower Miocene (Upper Burdigalian) is recognized; its habitat appears to have been freshwater, but very close to the sea. Two new marine neritiliid species from the Aquitaine Basin are described: Bourdieria favia sp. nov. from the Upper Oligocene and Pisulinella aucoini sp. nov. from the Lower Miocene. A third undescribed species from the Lower Miocene is referred to the same family and related to Pisulinella. The Oligocene species has a strong spiral sculpture, a character completely absent in previously known neritiliid species. The genus Agapilia, founded on juvenile N. neritinoides and adult Vitta picta, appears to be a junior synonym of the genus Vitta. The associated occurrence of shells of the families Neritiliidae, Neritopsidae and Pickworthiidae (well-known inhabitants of Indo-West Pacific submarine caves) at Peyrère suggest the first occurrence of a characteristic assemblage of dark submarine caves during the Oligocene. Both factorial analysis and relative abundance show that at Peyrère these families are associated with other cryptic fossils (various gastropods, bivalves, Brachiopoda, corals, Annelida). However, there are indications of other submarine cave assemblages in various Cenozoic deposits from the Palaeocene to the middle Miocene. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 140, 447–467.
The Aquitaine and Paris basins of France and the northern Gulf Basin of the southeastern United States
contain excellent Paleogene marine sequences. Paleogene stages or groups within these basins have
been used as standards for worldwide stratigraphic correlations for over one hundred years. In the northern
Gulf, the Eocene and Oligocene marine sections are particularly weil preserved along the eastern flank of
the Mississippi Embayment in Mississippi and south western Alabama. These marine sections can be closely
correlated with tnose of the Aquitaine and Paris basins by means of calcareous nannoplankton as demonstrated by Pujol (1979), Siesser and Dockery (1985), and others
A very rich Late Oligocene mollusc fauna from a coastal clif at Mogenstrup, North of Skive, Jutland, Denmark) was studied. A summary of the Late Paleogene sedimentary sequence in BW Jutland is given, the locality and the sequence exposed are described. Lithostratigraphical, magnetostratigraphical and biostratigraphical correlations are suggested. A list of the mollusc species is given, comparisons with other Danish and German faunas of Late Oligocene age are made and palaeoecological interpretations are suggested. In the systematical part the subgenus Andersondrillia is introduced within the genus Microdrillia. Several taxa are discussed and the following new species and subspecies are described: Limopsis (Pectunculina) lamellata chattica, Limopsis (Pectunculina) vonderhochti, Collonia (Collonia) troelsi, Lepetella helgae, Lepetella jytteae, Tubiola subangulata, Cerithiopsis (s. lat.) antonjansei, Laiocochlis (Laiocochlis) supraoligocaenica, Triforis (Trituba) sorgenfreii, Cirsotrema (Opaliopsis) subglabra, Searlesia ravni, Angistoma brueckneri danica, Clavatula mogenstrupensis, Microdrillia (Microdrillia) ingerae, Microdrillia (Andersondrillia) brejningensis, Pleurotomella (Pleurotomella) rasmusseni, Rimosodaphnella lappanni and Actaeopyramis (s. lat.)pseudopunctata.
The marginellid gastropod Hydroginella caledonica (Jousseaume, 1876) has been observed parasitizing sleeping fishes of the families Scaridae, Serranidae and Pomacentridae at coral reefs in New Caledonia during the night, The snail inserts its proboscis in the fish tissues and probably pumps some body fluids. Fish parasitism is also exhibited by another species in the genus Tateshia Kosuge, 1986, here transferred from the Olividae to the Marginellidae. Several Indo-Pacific marginellids conchologically resemble H. caledonica, and it is anticipated that more species in the family will prove to have a similar feeding biology.
Feeding habits of the over 200 living species of Cancellarlidae are largely un known. The Cooper's nutmeg, Cancellaria cooperi, was seen by divers on the dorsal surface ofPacific electric rays, Torpedo californica. C. cooperi was observed to parasit ize electric rays in the laboratory. The snails made small cuts on the ray's ventral surface and inserted their proboscises into the wounds. Snails were also observed to insert their proboscises into the mouth, gill slits, and anus, as well as previously exist ing wounds. After insertion ofthe proboscis, the snails appeared to suck blood from the ray. In Y-maze experiments, the snails actively sought out electric rays, but not other common California bottom fishes. Host location appeared to be by chemosen sory means. In the absence ofelectric rays, snails remained buried in the sand without moving for at least 12 days. Field observations indicate that snails may travel as much as 24 meters in search of rays.
When studying the biology and ecology of Juliidaeliving representatives (Gastropoda, Opisthobranchia, Sacoglossa) a close relationship can be observed between these animals and green Algae of the genus Caulerpa (Chlorophycea, Siphonophycidae). The animal feeds on the host plant by sucking the sap of the Alga, and moreover seems to use the ingested chloroplasts for a functional photosynthesis. Each species of Juliidae is found living on only one (or sometimes two) species of Caulerpa.The fossil Juliidae prove the existence of Caulerpagrowing at the same places, though these algae do not leave any direct remnant of their presence. Applying this to the Paris Basin Eocene, where the Juliidae are relatively abundant and varied, a quite accurate estimate is given for many characteristics of the paleo-environment, by analogy with the narrow and strict ecological needs of the living representatives (bathymetry, temperature and oxygenation of water, and presence of Caulerpa sea weeds).A review of the Paris Basin eocene species is given, including their stratigraphical distribution and drawings of the shells.