MAINWARINGIA NEVILL, 1885, A LITTORINID GENUS FROM ASIATIC MANGROVE FORESTS, AND A CASE OF PROTANDROUS HERMAPHRODITISM

On the basis of reproductive anatomy and radula, the poorlyknown genus Mainwaringia Nevill, 1885, is shown to belong tothe Littorinidae. The genus is represented by two species, M.leithii (E.A. Smith, 1876) from India to Vietnam, and a newspecies, M. rhizophila, from Malaysia to Hong Kong. Both occurin mangrove forests. The reproductive anatomy of M, rhizophilais described in detail, and it is interpreted as a protandroushermaphrodite, a condition unique in the Littorinacea. In theintersexual and female stages both closed pallial oviduct andopen prostate are present in the mantle wall, suggesting thatthese structures are not strictly homologous. The affinitiesof Mainwaringiaare discussed, and it is concluded that it maybe most closely related to Littorina s.s. (Received 30 May 1986;     

Anatomy and systematics of bathyphytophilid limpets (Mollusca, Archaeogastropoda) from the northeastern Pacific

Bathyphytophilus diegensis sp. n. is described on basis of shell and radula characters. The radula of another species of Bathyphytophilus is illustrated, but the species is not described since the shell is unknown. Both species feed on detached blades of the surfgrass Phyllospadix carried by turbidity currents into continental slope depths in the San Diego Trough. The anatomy of B. diegensis was investigated by means of semithin serial sectioning and graphic reconstruction. ‘The shell is limpet-like; the protoconch resembles that of pseudococculinids and other lepetclloids. The radula is a distinctive, highly modified rhipidoglossate type with close similarities to the lepetellid radula. The anatomy falls well into the lepetelloid bauplan and is in general similar to that of Pseudococculinidae and Pyropcltidae. Apomorphic features are the presence of gill-leaflets at both sides of the pallial roof (shared with certain pseudococculinids), the lack of jaws, and in particular many enigmatic pouches (bacterial chambers?) which open into the postcrior oesophagus. Autapomorphic characters of shell, radula and anatomy confirm the placement of Bathyphytophilus (with Aenigmabonus) in a distinct family, Bathyphytophilidac Moskalev, 1978. As revealed by a cladistic study, the Bathyphytophilidae should be classified within the Lepetelloidea close to the Lepetellidae, Pyropeltidae, and Pseudococculinidae.     

ANATOMY AND RELATIONSHIPS OF THE BONE-FEEDING LIMPETS, COCCULINELLA MINUTISSIMA (SMITH) AND OSTEOPELTA MIRABILIS MARSHALL (ARCHAEOGASTROPODA)

The anatomy of Cocculinella minutissima (Smith, 1904) and Osteopeltamirabilis Marshall, 1987 is described. Both species belong tothe Lepetelloidea and are closely related to Addisonia Dall,1882, the anatomy of which has been recently described by theauthor. Commonly derived (symapomorphic) characters of all threegenera are found especially in the genital system (hermaphrodites,tcstis and ovary separated, with separated ducts, open seminalgroove to the unmodified right cephalic tentacle), and in thealimentary tract (paired oesophageal glands). Distinct similaritiesin genital and excretory system (large right kidney isolated;hermaphrodites, separated gonads) with the Pseudococculinidae,Pyropeltidae and Lepetellidae justify a uniting superfamilyLepetelloidea, the anatomy of which is quite different fromthat of the Cocculinoidea (Cocculinidae and Bathy-sciadiidae) Osteopelta has retained certain primitive characters (rhipidoglossateradula, true stomach), but is specialized in having a snout-likehead, a concentrated cerebropedal ring, and secondary gill leaflets(vestigial gill in Cocculinella, distinct gill leaflets in Addisonia).Cocculinella and Addisonia share additional synapomorphic featuresof the posterior alimentary tract (reduction of stomach, intestineforms a large sac, midgut gland contains dark granules). Severalaut-apomorphies of each genus justify their status as distinctfamilies. Relationships to the (coiled) Choristellidae, whichfeed on empty egg-cases of sharks or skates (as do addisoniids)and have a cocculinellid-like radula type, are discussed ^*Present address: Insitut fr Zoologie der Universitat, Technikerstr.25; A-6020 Innsubruck, Auttria (Received 10 March 1987;     

Sinistrexcisa, a New Genus of Land Snail from Central West Africa with Four New Species (Gastropoda: Pulmonata: Streptaxidae)

A new genus of Streptaxidae with four new species is describedfrom Central West Africa, viz. Sinistrexcisa cameruniae (typespecies) from Southwest Cameroon, and S. iradieri, S. cogoensisand S. fang from Equatorial Guinea. In addition to the shells,the genital anatomy of three species and the radula of one speciesare described. The species of Sinistrexcisa resemble some taxaof the heterogeneous genus Ptychotrema s.l., but differ conchologicallyby, among others, the extremely long and displaced aperturalsinus and the sinistrally coiled last quarter whorl, and anatomicallyby the morphology of the penis, especially the inner spinulation.A spermatophore was observed in the lower (distal) portion ofthe penis of a specimen of S. fang. This is probably the first recordof a spermatophore in the family Streptaxidae. (Received 9 October 1997; accepted 1 July 1998)     

A NEW SPECIES OF BERTHELLA BLAINVILLE, 1824 (OPISTHOBRANCHIA: NOTASPIDEA) FROM THE CANARY ISLANDS (EASTERN ATLANTIC OCEAN), WITH A RE-EXAMINATION OF THE PHYLOGENETIC RELATIONSHIPS OF THE NOTASPIDEA

Berthella canariensis is described from Canary Islands. Themantle is smooth and its ground colour is grey, with black andopaque white spots scattered regularly all over the dorsal surface.White spots are less abundant than black ones. The posterior halfof the mantle has areas of with a paler ground colour that are variablein size. Berthella canariensis has several features that distinguishit from other described members of Berthella. It had a broadradula with numerous teeth per half-row. However, other aspectsof its anatomy, such as the absence of a medial buccal glandand the presence of a tuberculate gill, distinguish it fromother species with a broad radula. As the present species has two features found in some speciesof Pleurobranchus and several new higher taxa have been describedrecently, Willan's (1987) phylogenetic hypothesis was re-analysed.This analysis largely supports the hypothesis presented by Willan. The sister-group relationship of B. Canariensis with B. californiais supported by two synapomorphies. The relationship of thesetwo species to other species of Berthella is poorly resolvedin the present analysis and requires additional study of allmembers of the genus. Similarly, questions of the monophylyof Bathyberthella, Polictenidia, Parabathyberthella, Tomthompsoniaand Berthella require the consideration of additional speciesand comparison with other member of Berthella and Berthellina. Despite the need for further study, the mohophyly of the cladecontaining Bathyberthella, Polictenidia, Parabathyberthellais well supported. Similarly, numerous synapomorphic featuresconfirm the monophyly of the clade containing Bathyberthella,Polictenidia, Parabathyberthella, Tomthompsonia, Berthellinaand Berthella, and its sister-group relationship with the Pleurobranchus. The present study reveals that the Notaspidea have three distinctconfigurations of triaulic reproductive systems, not previouslydifferentiated. (Received 19 January 1998; accepted 15 November 1999)     

Atebbania Bernasconii, a New Genus and Species from Subterranean Waters of the Tiznit Plain, Southern Morocco (Gastropoda: Hydrobiidae)

The new genus Atebbania is described for a new hydrobiid species,A. bernasconii, which lives in groundwaters of southern Morocco.Of the Hydrobiidae genera with known shell and anatomy Moitessieriais the closest to Atebbania. The two share the following characters:shell elongate; teleoconch surface with evident microsculpture;seminal receptacle absent. Atebbania is distinguished from Moitessieriaby: shell ovate; penis with a) apical stylet, b) one lobe bentdownward on left (inner) side and c) penial duct running nearthe right (outer) side; posterior end of foot indented. Atebbaniabernasconii n. sp., lives in a limited area, the Tiznit plainin southern Morocco. Other stygobiont hydrobiids from otherareas of Morocco are currently being studied. None of them appearsto be closely related to A. bernasconii or to the species ofMoitessieria (Received 10 February 1998; accepted 30 April 1998)     

Anatomy of Afropomus balanoideus (Mollusca,Gastropoda, Ampullariidae) and its implications for phylogeny and ecology

Summary The hitherto unknown anatomy of Afropomus balanoideus is described. Its systematic position within the Ampullariidae is indicated by the possession of the following autapomorphic characters of the Ampullariidae: presence of a lung sac, an ampulla-shaped aorta anterior, a bipartite copulatory organ of pallial origin, a left-sided zygoneur nervous system, a bipartite kidney, a lamellate osphradium, labial tentacles, an ingestion and an egestion sipho and a radula with strong teeth. The pallial vas deferens is completely closed, while the pallial oviduct is anatomically open in its distal part but functionally closed, because it is embedded in the surrounding mantle tissue. The copulatory organ is of pallial origin and innervated by the right pleural ganglion. The plesiomorphic states of some characters indicate that Afropomus balanoideus might represent the adelphotaxon of the remaining Ampullariidae. The morphological structures show that this species is adapted to an amphibious mode of life and to aestivation, as has been shown for other species of Ampullariidae.     

THE FUNCTIONAL ANATOMY OF THE NERITACEAN LIMPET PHENACOLEPAS OMANENSIS BIGGS AND SOME COMPARISON WITH SEPTARIA

The shell of Phenacolepas and Seplaria is produced by a disproportionateexpansion of the last whorl of the typical neritid shell, withthe right and left columellar muscle an extension of that partarising from the shell and not the columella. The columellais a posterior ridge near the level of the protoconch. In contrastto zeugobranchs the mantle cavity is large, extending beneaththe viscera: the organization and disposition of the organsrelated to it are similar to those of Nerita. Poor development of pedal musculature of Phenacolepas may berelated to the sheltered environment. As in other limpets thereis a marginal pedal flange acting as a seal around the areaof low pressure which arises when the foot is used as a sucker.The internal anatomy reflects neritacean conservatism, but thereare characters, previously undescribed, which justify the separationof the genus in a separate family, the Phenacolepadidae: theelaboration of the mantle edge to resemble that of some zeugobranchs;the retention of an internal operculum; relatively sparse developmentof pedal musculature; the loss of the right auricle; erythrocytesin the blood; a vaginal papilla related to an ovipositor; theabsence of a crystal sac and modifications of the nervous systemto give more direct nervous pathways. (Received 12 September 1982;     

Indirect evidence for ecophenotypic plasticity in radular dentition of Littoraria species (Gastropoda: Littorinidae)

In examination of radulae from all but one of the 36 speciesof the littorinid genus Littoraria we found extraordinary intraspecificvariation in those occurring on a range of substrates. Radulaefrom rock showed a less well developed `hood' on the rachidiantooth, a strikingly enlarged major cusp on each of the fivecentral teeth, fewer cusps on the outer marginal teeth and theradular ribbon was longer, when compared with radulae of conspecificsfrom plant substrates. The radulae of species found exclusivelyon rock differed in similar ways from those restricted to plantsubstrates (mangroves, driftwood and saltmarsh). We suggestthat this may be an example of phenotypic plasticity of radularform, induced by substrate and/or diet, as recently shown experimentallyin another littorinid genus. The mechanism of inducible plasticitydeserves further study. Ecotypic variation in the radula maybe widespread in littorinids, and radular characters shouldtherefore be used with caution in studies of taxonomy, phylogenyand adaptation. (Received 20 July 1998; accepted 10 November 1998)     

Reassessment of the Systematic Status of Miamira Bergh, 1875 and Orodoris Bergh, 1875 (Nudibranchia: Chromodorididae) in Light of Phylogenetic Analysis

The external morphology and anatomy of the opisthobranch gastropodsMiamira sinuata (van Hasselt, 1824) and Orodoris miamiranaBergh, 1875, the type species of the genera Miamira Bergh, 1875and Orodoris Bergh, 1875, and their phylogenetic relationshipsare studied. The phylogeny obtained supports the placement ofM. sinuata and O. miamirana in the genus Ceratosoma J. E. Gray, 1850.Therefore, Miamira and Orodoris become synonyms of the seniorvalid name Ceratosoma. In addition, the family name MiamiridaeBergh, 1891, based on Miamira, is newly recognized as a synonymof Chromodorididae Bergh, 1891. Ceratosoma sinuata and C. miamirana are more closely relatedto the highly derived Ceratosoma alleni than to other membersof the genus. C. miamirana appears to present reversal to theplesiomorphic state in the body shape and has secondarily lostits mantle glands. (Received 5 January 1998; accepted 23 April 1998)     

RADULAR PRODUCTION RATES IN TWO SPECIES OF LACUNA TURTON (GASTROPODA: LITTORINIDAE)

The molluscan radula is a dynamic organ, both in terms of itsuse and production. New rows of teeth are constantly producedat the posterior end of the radula, while older, worn teethare shed anteriorly, producing a dynamic equilibrium. We useda cold-shock to mark the radular ribbon and measure tooth rowproduction rates in two gastropod species, Lacuna vincta (Montagu)and L. vanegata Carpenter. We found that the average tooth rowproduction rate at 10–11°C did not differ betweenthese two species, and was 2.94 (SE = 0.002) rows per day forLacuna vincta and 2.97 (SE = 0 002) for L. vanegata Inter-individualvariability in production rate was very low, and was correlatedwith shell length, smaller individuals had slightly higher productionrates. The total length of the radular nbbon varied greatlyamong individuals, ranging from 47 to 94 (2.57 to 5.68 mm) rowsin L vincta and 53 to 99 rows (2.80 to 7.14 mm) in L vanegata,and was only somewhat correlated with the length of the shelLThis great variability will result in large differences amongindividuals in the time it takes to replace the radula totally,from 14.96 to 35.44 days in L vincta and from 17 43 to 39 69days in L. vanegata. (Received 1 September 1995; accepted 20 November 1995)     

CONSUMPTION OF AMPHIPODS BY THE NEW ZEALAND LAND SNAIL WAINUIA URNULA (PULMONATA: RHYTIDIDAE)

An unusual carnivorous diet was documented for the rhytididsnail Wainuia urnula urnula (Pfeiffer) from the southern North Island,New Zealand. Eighty-two percent of 315 samples of faeces or gutcontents contained remains of landhoppers (Crustacea: Amphipoda).Earthworms (Oligochaeta) were the second most common food typeidentified, but occurred in only 4 percent of samples. In the laboratory,W. urnula urnula captured landhoppers by rapidly everting theTVU-section odontophore beneath the prey and immediately drawingit into the mouth in a single action. Diet samples from the allopatriccongeners W. edwardi (Suter) (n 5 51) and W. clarki Powell (n5 7) contained no remains of landhoppers, and these snails didnot eat landhoppers in the laboratory. The diet of these specieswas dominated by earthworms. The subspecies W. u. nasuta ateboth earthworms and amphipods with similar frequency (n 5 40).Individual teeth on the radula of W. urnula urnula had a simpleblade-like cusp like other Wainuia species, but there were fewerteeth per row and fewer rows on the whole radula than in otherspecies. W. u. nasuta had a similar number of rows of teethto W. clarki and W. edwardi, but the number of teeth per rowwas intermediate between these species and W. u. urnula. Recordsof pulmonate species preying on arthropods are rare, yet inthe case of W. urnula this specialization has been accompaniedby minimal morphological change. (Received 22 December 1998; accepted 11 March 1999)     

Toxoglossan gastropods of the subfamily Crassispirinae (Turridae) lacking a radula, and a discussion of the status of the subfamily Zemaciinae

Two new species of Horaiclavus, lacking radula, venom glandand proboscis, are described. The genus is placed in the subfamilyCrassispirinae (Turridae). Both species possess a peculiar foregutstructure, the muscular rhynchodaeal outgrowth situated in therhynchocoel. The possible function of the rhynchodaeal outgrowthis discussed. Other studied species of Horaiclavus possess aradula of a typical ‘crassispirine’ type but lackthe outgrowth. The anatomy of the foregut of the new speciesis superficially similar to that of Zemacies excelsa (Turridae:Zemaciinae), which also possesses an additional structure ofthe rhynchocoel, namely the ‘pyriform gland’. Conchologically,there is no resemblance between Zemacies and Horaiclavus andit is concluded that similar foregut arrangement appeared independentlyin both lineages. A new monotypic subfamily Zemaciinae was erectedmostly on the basis of the unique foregut arrangement of Zemaciesexcelsa. We express doubts concerning the importance of thesecharacters in establishing a new taxon of subfamilial rank andtherefore the validity of the subfamily Zemaciinae. (Received 16 May 2007; accepted 1 October 2007)     

THE BIOLOGY AND FUNCTIONAL MORPHOLOGY OF MYOCHAMA ANOMIOIDES STUTCHBURY, 1830 (BIVALVIA: ANOMALODESMATA: PANDOROIDEA), WITH REFERENCE TO CEMENTATION

The small, exclusively Australasian, anomalodesmatan familyMychamidae comprises only two genera; the shallow-burrowingMyadora and the cementing Myochama. This paper describes theanatomy ad cementing behaviour of Myochama anomioides and drawscomparisons with Myadora. The anatomy of Myochama anomioides is little different fromthat previously described for Myadora, except that they aremirror images. Valve inequality is not reflected in the organsof the mantle cavity in either taxon. Such differences whichare present, for example the reduction of the foot in Myochama,mostly relate to the adoption of a sessile habit. There arefew idfferences in mantle folds of the cementing and non-cementinggenus, except that in M. anomioides the right mantle fold, whichsecretes the cemented valve, is thicker and less well-developedthan the left. During the cementation process, the periostracumsecreted by the right fold is thinner and has a quilted appearance. Individuals of Myochama anomioides cement by their right valveonce they have recahed a size of 1.2—3.9 mm. They appear tohave a preference for attaching to the posterior portions ofa diversity of living, shallow infaunal bivalves. The pronounced stereotypicorientation they adopt suggests that these hosts are most oftenalive at the time of colonization and that the mychamids benefit fromthe relationship. The relationship, however, is not obligate. Theyare capable of attaching to other shelly or rock debris, butdo so at a lager size, presumaby whe the preferred substrataare not available. The thin layer of extra-periostracal cementlacks the calcereous crystalline nature of oyster cement, insteadof being largely composed of organic material. This cement ispresumably secreted by glands within the mantle, but these havenot been identified. Indeed, the mantle lacks arenophilic glandswhich might have been thought a suitable candidate for supplyingcement. (Received 14 December 1999; accepted 4 February 2000)     

A new Georissa (Gastropoda: Neritopsina: Hydrocenidae) from a limestone cave in Malaysian Borneo

In a previous paper, we have reported on a new, troglobiticspecies of Georissa and its possible parapatric origin fromGeorissa saulae Benthem-Jutting, 1966, which occurs outsidethe cave system of Batu Sanaron, a limestone outcrop in Sabah,Malaysian Borneo. These analyses were based on genetic and morphometricdata. Here, we formally describe the new species adding anatomicaldata derived from dissections and histological serial sectionsas well as fine structural data of shell, operculum and radula,and compare it with its stem species. The two species differin shell and radular morphology as well as genital characters.Since we found anatomical differences between very closely relatedspecies, we assume that dissections would be of general usefor the taxonomy of Georissa and the remaining nominal genus-grouptaxa of the poorly known Hydrocenidae.