Home Acknowledgments Conventions Glossary Maps References Links Articles Thumbnails Species list _______________   Pyramidellidae Murchisonellidae Cimidae Architectonicidae Orbitestellidae Omalogyridae Xylodisculidae Rissoellidae	Lower Heterobranch Addendum Some authors group the "lower Heterobranchia", Opisthobranchia and Pulmonata within the clade Heterobranchia. The details of the relationships appear to still be in flux. So, we've decided to include an addendum to the site covering families currently placed in the lower Heterobranchia. This is a heterogeneous group that share some features with the more basal opisthobranchs dealt with elsewhere on the site (the families Ringiculidae, Acteonidae, Bullinidae and Aplustridae are sometimes placed in the lower Heterobranchia rather than in the Opisthobranchia). Lower heterobranch families include the Cimidae, Orbitestellidae, Tjaernoeiidae, Xylodisculidae, Architectonicidae, Glacidorbidae, Mathildidae, Omalogyridae, Pyramidellidae, Amathinidae, Murchisonellidae,  Rissoellidae, Valvatidae, Cornirostridae and Hyalogyrinidae (with some variation depending on source). At least the Pyramidellidae, Murchisonellidae, Cimidae, Architectonicidae, Orbitestellidae, Omalogyridae, Xylodisculidae and Rissoellidae are known from Hawaii. Unlike for the opisthobranchs, we haven't kept extensive notes on these families--no running log of finds or detailed records of the source of photographed animals. Therefore, we can't guarantee that it includes the latest names and it may not be as comprehensive as the opisthobranch section. Pyramidellidae The family Pyramidellidae includes mostly small, elongate snails that live primarily as ectoparasites, usually of other mollusks and annelids. However, a few of the larger ones are free living. They lack a radula, using an elongate proboscis to pierce the skin of their host or prey. They are hermaphroditic. Around 48 species are known from Hawaii in the genera Chrysallida, Cingulina, Elusa, Eulimella, Evalia, Herviera, Iolaea, Koloonella, Megastomia, Miralda, Monotygma, Odostomella, Odostomia, Ondina, Oscilla, Otopleura, Pyramidella, Syrnola, Tiberia, and Turbonilla. Information on this family is derived primarily from reconciling Pilsbry (1917-1921), Kay (1979) and Severns (2011) with each other and with our own material. So, the IDs should be viewed as tentative, pending further work. Chrysallida cf. cossmanii Cingulina(?) sp #1 Elusa sp. #1 Eulimella lacteola Eulimella quarta Eulimella quinta Eulimella secunda Eulimella sp. #1 Eulimella sp. #2 Eulimella sp. #3 Eulimella(?) sp. #4 Eulimella sp. #7 Evalea eclecta Evalea waikikiensis Herviera gliriella Herviera sp. #1 Herviera sp. #2 Iolaea sp. #1 Koloonella(?) hawaiiensis Koloonella(?) sp. #1 Megastomia stearnsiella Miralda paulbartschi Miralda scopulorum Monotygma(?) sp. #1 Odostomella chorea Odostomia cf. chariclea Odostomia cf. gulicki Odostomia cf. oxia Odostomia rosacea Odostomia sp. #4 Ondina sp. #1 Oscilla pupu Otopleura mitralis Pyramidella dolabrata Pyramidella sulcata Syrnola aciculata Syrnola cf. subcinctella Syrnola cf. teretiuscula Tiberia japonica Tiberia sp. #2 Turbonilla lirata Turbonilla thaanumi Turbonilla varicosa un. sp. #5 un. sp. #8 un. sp. #9 un. sp. #18 un. sp. #19   Murchisonellidae The Murchisonellidae are minute, white, elongate snails that resemble Pyramidellids. There is at least one species known from Hawaii in the genus Murchisonella. Murchisonella columna   Cimidae The Cimidae are minute, white, elongate snails that resemble Pyramidellids. There are at least four species known from Hawaii, probably in the genera Cima and Graphis. Cima(?) sp. #1 Graphis(?) sp. #1 Graphis sp. #2 Graphis sp. #3   Architectonicidae The Architectonicidae (commonly referred to as sundials) include top-shaped or helical snails, often with a deep umbilicus. They resemble the pyramidellids in having a hyperstrophic protoconch (coiled to the left rather than the right). Some species have terraced, horn-like operculums. Most feed on zooanthineareans although the genera Architectonica and Philippia feed on corals as adults. The sexes are separate. At least 14 species are known from Hawaii in the genera Architectonica, Granosolarium, Heliacus, Pseudomalaxis, Psilaxis and Spirolaxis. The species Torina solcifera Pease, 1869 appears to be unidentifiable with modern material. (Kay, 1979) Architectonica gualtierii no photo available Architectonica nomotoi Architectonica perspectiva no photo available Architectonica trochlearis no photo available Granosolarium excavatum Heliacus areola Heliacus implexus Heliacus mighelsi Heliacus sterkii Heliacus trochoides Psilaxis oxytropis Psilaxis radiatus no photo available Spirolaxis exornatus Spirolaxis rotulacatharinae   Orbitestellidae The Orbitestellidae are minute, white, helical snails with a broad umbilicus. There are at least three species known from Hawaii in the genera Boschitestella and Orbitestella. Boschitestella cf. eloiseae Orbitestella cf. bermudezi Orbitestella regina   Omalogyridae The Omalogyriridae are minute, brown, planispiral snails. At least two species are known from Hawaii in the genus Omalogyra. Omalogyra japonica Omalogyra sp. #1   Xylodisculidae The Xylodisculidae are minute, smooth, helical snails with a broad umbilicus. At lease one species is known from Hawaii in the genus Xylodiscula. Xylodiscula sp. #1   Rissoellidae The Rissoellidae are minute, conical snails with transparent shells. They have both cephalic tentacles and elongate oral lobes. They are hermaphroditic. At lease three species are known from Hawaii in the genus Rissoella. Rissoella cf. confusa Rissoella longispira Rissoella sp. #1
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