Reassessment of the trophic position of Bullidae (Gastropoda: Cephalaspidea) and the importance of diet in the evolution of cephalaspidean gastropods

A review of the available data on the diet of species of Bullidae is presented. Their trophic level is reassessed through gut content analysis of worldwide species from various habitats. Gut contents were identified by light and scanning electron microscopy. The previous claims of omnivory and carnivory were not supported. Worldwide species of Bullidae feed preferentially on algae and secondarily on diatoms, and are therefore herbivorous. The influence of dietary specialization on the evolution of cephalaspidean gastropods was assessed by superimposing the diet onto a molecular family-level phylogeny. Herbivory was found to be the plesiomorphic condition, with carnivory having arisen independently two or three times. This evidence suggests that dietary specialization has played a major role in the adaptive radiation of the group.     

Behavioral thermoregulation of Bulla gouldiana (Gastropoda: Opisthobranchia: Cephalaspidea)

1. 1. The preferred temperature of Bulla gouldiana is 26.7–28.7°C.

2. 2. In constant scotophase, photophase, and light and dark photoperiod the organisms do not have a diel cycle of thermoregulation.

3. 3. It takes the animal 6–16 h to reach the preferred temperature.

4. 4. The lowest and highest temperatures visited were 11 and 33°C.

5. 5. Spawning of the species occurred in the thermal gradient between 27 and 28.5°C.

     

Integrative systematics of northern and Arctic nudibranchs of the genus Dendronotus (Mollusca,Gastropoda), with descriptions of three new species

The taxonomy of common northern nudibranch molluscs of the genus Dendronotus in the vast cold regions of Eurasia remains largely unknown. Abundant material collected in many localities from the Barents Sea, via the Arctic region, to the north‐west Pacific was analysed for the first time. An integrated approach combining morphological and ontogenetic data with molecular four‐gene (COI, 16S, H3, and 28S) analysis reveals seven species, including three previously undescribed. Dendronotus frondosus (Ascanius, 1774) and Dendronotus dalli Bergh, 1879 were commonly considered as amphiboreal species; however, according to this study they are restricted to the North Atlantic and the North Pacific, respectively. In the north‐west Pacific two new species were discovered, D endronotus kamchaticus sp. nov. and D endronotus kalikal sp. nov. , that are externally similar to D. frondosus, but that show significant distance according to molecular analysis and are considerably different in radular morphology. In the North Atlantic a new species D endronotus niveus sp. nov. , sibling to North Pacific D. dalli, is revealed. The separate status of North Atlantic Dendronotus lacteus (Thompson, 1840) is confirmed, including considerable range extension. The essential similarity of early ontogenetic stages of radular development common for species with disparate adult radular morphology (such as D. frondosus and D. dalli) is shown, and its importance for taxonomy is discussed. © 2015 The Linnean Society of London     

Systematic revision of the arboreal snail Satsuma albida species complex (Mollusca: Camaenidae) with descriptions of 14 new species from Taiwan

The taxonomy of the endemic arboreal snail Satsuma albida species complex from Taiwan was unclear due to the animals' highly similar morphology, and their nocturnal and strict arboreal behaviour, leading to difficulties in collecting living specimens. This article is the first comprehensive comparative study on the systematics and taxonomy of this species complex using external morphology, anatomy of the reproductive system and molecular phylogeny. Consequently, two subspecies of S. albida are raised to species status, namely S. insignis and S. mollicula. Fourteen new species are also described. Fourteen of the 17 species showed polymorphism in banding pattern amongst populations and other species retained the whitish unity as seen in S. albida. Distributions of almost all taxa are geographically limited, with the exception of S. polymorpha sp. nov . The phylogeny of these species was reconstructed using 20 morphological characters and molecular data from the partial sequences of mtDNA CO1 and 16S rRNA genes, and the complete ITS2 sequence. The molecular phylogeny revealed three subclades (west, east and polymorpha clade) and revealed that these snails are monophyletic, originating from a ground‐dwelling ancestor. © 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 154 , 437–493.     

Systematic revision and molecular phylogeny of the land snail genus Fruticocampylaea (Gastropoda: Hygromiidae) from the Caucasus region

This paper presents a systematic revision and a molecular phylogenetic analysis of the Caucasian land snail genus Fruticocampylaea. The genus is newly delimited based on the reduction of the cavities adjoining the seminal duct in the penial papilla. Shell and genitalia of all five species (F. narzanensis, F. kobensis, F. tushetica sp. nov., F. christophori, F. daghestana) are described and figures provided. All synonyms and all locality records are listed. Maximum likelihood and Bayesian analyses of mitochondrial and nuclear DNA sequences (fragments of cox1, 16S rDNA, ITS2 and 28S rDNA) confirm the monophyly of Fruticocampylaea. The reduction of the dart apparatus and the conical plug, via which the dart apparatus inserts into the vagina, as well as the molecular phylogenetic analyses, suggests a sister group relationship between Fruticocampylaea and Circassina (without Abchasohela). Furthermore, the molecular phylogenetic analyses indicate that the Fruticocampylaea species originated in a rapid radiation. The uplift of the Greater Caucasus in the Late Miocene or Pliocene or climatic changes at the end of the Pliocene or in the early Pleistocene may have caused the radiation of Fruticocampylaea. Low intraspecific variability can be explained by population bottlenecks during Pleistocene glacial periods followed by postglacial population increase.

http://zoobank.org/urn:lsid:zoobank.org:pub:AB15158D-21A3-4945-8D49-F7DE8E406E2B     

Molecular phylogenetics of Caenogastropoda (Gastropoda: Mollusca)

Caenogastropoda is the dominant group of marine gastropods in terms of species numbers, diversity of habit and habitat and ecological importance. This paper reports the first comprehensive multi-gene phylogenetic study of the group. Data were collected from up to six genes comprising parts of 18S rRNA, 28S rRNA (five segments), 12S rRNA, cytochrome c oxidase subunit I, histone H3 and elongation factor 1alpha. The alignment has a combined length of 3995 base positions for 36 taxa, comprising 29 Caenogastropoda representing all of its major lineages and seven outgroups. Maximum parsimony, maximum likelihood and Bayesian analyses were conducted. The results generally support monophyly of Caenogastropoda and Hypsogastropoda (Caenogastropoda excepting Architaenioglossa, Cerithioidea and Campanilioidea). Within Hypsogastropoda, maximum likelihood and Bayesian analyses identified a near basal clade of nine or 10 families lacking an anterior inhalant siphon, and Cerithiopsidae s.l. (representing Triphoroidea), where the siphon is probably derived independently from other Hypsogastropoda. The asiphonate family Eatoniellidae was usually included in the clade but was removed in one Bayesian analysis. Of the two other studied families lacking a siphon, the limpet-shaped Calyptraeidae was associated with this group in some analyses, but the tent-shaped Xenophoridae was generally associated with the siphonate Strombidae. The other studied hypsogastropods with an anterior inhalant siphon include nine families, six of which are Neogastropoda, the only traditional caenogastropod group above the superfamily-level with strong morphological support. The hypotheses that Neogastropoda are monophyletic and that the group occupies a derived position within Hypsogastropoda are both contradicted, but weakly, by the molecular analyses. Despite the addition of large amounts of new molecular data, many caenogastropod lineages remain poorly resolved or unresolved in the present analyses, possibly due to a rapid radiation of the Hypsogastropoda following the Permian-Triassic extinction during the early Mesozoic.     

An integrative approach to species delimitation in Benthomangelia (Mollusca: Conoidea)

DNA sequences are currently used to propose primary hypotheses of species delimitation, especially when morphological variability is difficult to assess. In an integrative taxonomy framework, these hypotheses are then compared with other characters, such as morphology or geography, to produce robust species delimitations. For this purpose, the cytochrome oxidase subunit I (COI) gene has been sequenced for almost 50 specimens of the genus Benthomangelia , a deep-sea marine gastropod genus, collected in the South-West Pacific. Five genetic groups, displaying low and high genetic distances respectively within and between groups, were defined. COI hypotheses were compared with both the results obtained with the independent nuclear 28S gene and with an elliptic Fourier analysis of the shape of the last whorl of the shell. 28S gene analysis confirmed the same well-supported groups as COI, and elliptic Fourier analysis identified several morphological characters that vary similarly to genetic variability.  © 2009 The Linnean Society of London, Biological Journal of the Linnean Society , 2009, 96 , 696–708.     

On the taxonomy of Littorina africana (Mollusca: Gastropoda)

L. africana and L. knysnaensis are regarded as two morphs of a single species which exhibits a genetic cline along the south-eastern coast of southern Africa. The dark brown morph knysnaensis dominates the western, cooler end of the cline and is replaced by the pale blue morph africana at the warmer end of the cline. These conclusions are based on evidence from the latitudinal distributions, the complete range of intermediate forms regarding shell colour and shell morphology and the lack of differences in redular morphology, penial morphology or habitat.     

The phylogenetic position of the heteropod Atlanta gaudichaudi Souleyet (Mollusca, Gastropoda), a spermatological investigation

The male adult, the spermatophore and the spermatozoa of Atlanta gaudichaudi are described. No parasperm are demonstrable. The ultrastructure of the spermatozoa is shown to differ fundamentally from that of the Archaeogastropoda and Neritopsina and to conform broadly with that of the Mesogastropoda (excepting Cyclophoracea, Viviparacea and Cerithacea), the Neogastropoda and the epitonacean heterogastropods. In having a nuclear fossa, containing the axoneme, which penetrates the entire length of the nucleus as the intranuclear canal, the spermatozoon especially resembles that of some members of the Rissoacea, Littorinacea, Eulimacea, Tonnacea, Volutacea and Conacea. Absence, in Atlanta of type 7 parasperm ( sensu Koike 1985), which characterize the Calyptraeacea, Cypraeacea, Tonnacea, Buccinacea, Volutacea (including the Mitracea) and most Conacea, or of type 8 parasperm of the Conidae, contraindicates heteropod relationship with these taxa. Relationship to the Rissoacea cannot be ruled out, though presence of oligopyrene, cusperm-like sperm in these (Bythiniidae) and pterotracheid heteropods is a questionable indication of affinity. Relationship of heteropods with the Littorinacea is suggested by similarity of the sperm, presence in carinariid heteropods and littorinids of nurse cells, and apparent homology of the male reproductive apparatus in both groups. The latter two similarities require confirmation, however. It is suggested that deposition of spermatophores on the exterior of the female in atlantid heteropods is a primitive mode of sperm transfer compatible with relationship with the Littorinacea.     

Towards a phylogeny and evolution of Acochlidia (Mollusca: Gastropoda: Opisthobranchia)

The Acochlidia are unique among opisthobranch gastropods in combining extremely high morphological and ecological diversity with modest species diversity. The phylogeny of acochlidians has never been addressed by cladistic means, as their evolution has remained unknown. This study gives a first overview on more than 150 biological and morphological characters that are potentially useful for phylogenetic analysis. Based on 107 characters, a parsimony analysis (PAUP) was performed for all 27 valid acochlidian species together with 11 (plus two) outgroup taxa. The resulting strict consensus tree shows a moderate overall resolution, with at least some bootstrap support for most resolved nodes. The Acochlidia are clearly monophyletic, and originate from an unresolved basal opisthobranch level. The Acochlidia split into the Hedylopsacea (Tantulum (Hedylopsis (Pseudunela (Strubellia (‘Acochlidium’, ‘Palliohedyle’))))) and Microhedylacea (Asperspina (Pontohedyle, ‘Parhedyle’, ‘Microhedyle’, (Ganitus, Paraganitus))). The formerly enigmatic Ganitidae, resembling sacoglossan opisthobranchs by having dagger‐like rachidian radular teeth, are likely to be highly derived microhedylids. The paraphyly of some of the traditionally recognized family level taxa induced a preliminary reclassification. From the phylogenetic hypothesis obtained, we conclude that the acochlidian ancestor was marine mesopsammic. The colonization of limnic systems occurred twice, independently: first in the Caribbean (with the development of the small interstitial Tantulum elegans), and second in the Indo‐Pacific, with a radiation of large‐sized benthic acochlidian species. The evolution of extraordinary reproductive features, such as hypodermic impregnation by a complex copulative aparatus in hedylopsaceans, cutaneous insemination via spermatophores in microhedylaceans, and gonochorism in Microhedylidae s.l. (including Ganitidae), is discussed. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 158 , 124–154.     

Molecular phylogenetic analysis of the Amiota apodemata and Amiota sinuata species groups (Diptera: Drosophilidae), with descriptions of four new species

The phylogenetic relationships among the East Asian species of the apodemata and sinuata species groups of the genus Amiota were investigated based on DNA sequences of the mitochondrial NADH dehydrogenase subunit 2 (ND2) gene. A total of 23 samples of 12 species were employed as in‐group taxa, and one sample for each of four other Amiota species were used as out‐groups. The results suggested with strong confidence the monophyly of both the apodemata and the sinuata groups, whereas the monophyly of the ‘apodemata group + sinuata group’ cluster was less supported. Based on its geographical distribution, the origin of the sinuata group is supposed to be southern China. Four new species were described from Guangxi and Yunnan, China: Amiota reikae Xu & Chen sp. nov. , Amiota guiensis Xu & Chen sp. nov. , Amiota hesongensis Xu & Chen sp. nov. , and Amiota polytreta Xu & Chen sp. nov. © 2013 The Linnean Society of London     

A revision and phylogenetic analysis of Stapeliopsis (Apocynaceae)

A survey of morphological characters is carried out for Stapeliopsis . The information obtained from this is combined with molecular data from the plastid trn L-F DNA region and ITS1 of the nuclear encoded 18S−26S rRNA cistron, to obtain a hypothesis of the evolutionary relationships among the species. It is shown that Stapeliopsis is monophyletic in a combined molecular and morphological analysis. Stapeliopsis is sister to a clade containing Huernia , Orbea and Tromotriche . The species of Stapeliopsis group into two clades. One contains S. khamiesbergensis , S. neronis and S. urniflora , and this is highly supported. The remaining species fall into an unsupported clade in which S. exasperata is sister to the others. The genera Hermanschwartzia Plowes and Neopectinaria Plowes are rejected. It is shown that a synapomorphy for Stapeliopsis is the laterally flattened inner corona-lobes, which touch the anthers only at their bases. Eight species of Stapeliopsis are recognized, with no subgeneric divisions.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 148 , 125–155.     

The taxonomy of two host-specific, cryptic dendronotoid nudibranch species (Mollusca:Gastropoda) from Australia including a new species description

Two host-specific, extremely cryptic, small dendronotoid nudibranchs from Australia are described and classified, and their phylogenetic position within the superfamily is discussed- Lomanotus vermiformis Eliot, 1908 subsists exclusively on the hydrozoan Lytocarpus philippinus (Kirchenpauer, 1872). Lomanotus stauberi Clark & Goetzfried, 1976 is newly synonymized with L. vermiformis . Marioniopsis platyctenea sp. nov. subsists exclusively on the alcyonacean Parerythropodium hicksoni Utinomi, 1972. Marianina rosea (Pruvot-Fol, 1930) is relocated to the Tritoniidae (wherein it forms a monotypic subfamily, Marianinae) because of possession of palmate rhinophoral clavi, the principal apomorphy of the Tritoniidae. The validity of using the form of the digestive gland as a basis for dividing the Tritoniidae is questioned since it is acknowledged that this organ has progressed from a solid (holohepatic) arrangement to a dispersed (cladohepatic) arrangement in parallel in several major nudibranch lineages; form thus offers merely homoeoplaseous phylogenetic characters. Separation of right and left digestive glands appears to be one of the first steps in the simultaneous and interdependent evolutionary processes of internal detorsion and external 'aeolidization' in nudibranchs.     

Polygyrid relations: a phylogenetic analysis of 17 subfamilies of land snails (Mollusca: Gastropoda: Stylommatophora)

The family of polygyrid land snails in North America is significant for its sympatric shell convergences, diversity of mating systems and complex zoogeography; its monophyly and its relation to other families has long been questionable. Cladistic analysis has been performed on one representative each of 17 subfamilies, including all three polygyrid subfamilies and one or more subfamilies each from all ten of the families that have been proposed as the polygyrid sister groups. Eighteen anatomical synapomorphies are used, of which eight are newly discovered, four are differently assessed from previous studies, and six are traditional. The resulting strict consensus tree of alternative maximum-parsimony cladograms is: (Acavidae (Ammonitellidae Corillidae ((Discidae Oreohelicidae) (Helminthoglyptidae Bradybaenidae Polygyridae (Thysanophoridae (Camaenidae Sagdidae)))))).
According to this working hypothesis, the Polygyridae are monophyletic, and their sister group remains unresolved, although the Acavidae, Ammonitellidae, Corillidae, Discidae and Oreohelicidae can be ruled out. Of the five classifications of stylommatophoran families that have been proposed in the past 12 years, the consensus tree is closest to that of Nordsieck. For future morphological work, three regions are recommended as potentially rich in unused phylogenetic information: the fertilization pouch-seminal receptacle complex, the ureter at the pneumostome and the ventral-chain ganglia. Simultaneous dissection, wkh side-by-side comparisons, is recommended over other methods for detecting homologies in land snails. Molecular characters should be exploited, because of the scarcity and the frequent homoplasy of morphological characters.     

Conchometrics, systematics and distribution of Melanopsis (Mollusca: Gastropoda) in the Levant

In this conchometric study, the systematics and distribution of the freshwater gastropod Melanopsis in the Levant are described. Of the ten species found, three are widespread, two have narrow distributions and five are known only from their type locality. Five smooth‐shelled species are recognized (buccinoidea, ammonis, dircaena, khabourensis and meiostoma). Within M. buccinoidea, Jordan Valley populations may belong to a separate subspecies. M. ammonis is clearly differentiated from buccinoidea of the nearby Jordan Valley, but less so from buccinoidea of more distant sites; differences between ammonis and meiostoma are significant but not diagnostic. Five species have ribbed shells. Within costata, four subspecies are recognized (in the northern Orontes, upper Jordan, Sea of Galilee, and in southernmost parts of the Levant). Throughout the Levant, M. buccinoidea frequently hybridizes with M. costata and fossil evidence suggests that these species have been hybridizing for the last 1.5 Myr. M. saulcyi differs from M. costata in its narrower shell and shorter, bumpier ribs and frequently hybridizes with M. buccinoidea throughout the Levant. Specimens from Homs differ from those of the Jordan Valley in their higher figurativity index, fewer ribs and lower rib density. M. germaini differs from M. costata in its more numerous ribs, M. pachya in its shorter ribs, and M. infracincta in its bumpy shell in which each rib has huge tubercles, with a pronounced ridge flanking the columella. Our conclusion that there are ten species in the Levant differs from previous studies that suggested only two subspecies of one species (or superspecies). This difference could stem from (1) our use of nonstandard as well as standard conchometrics, (2) a reappraisal of the importance of the shell vs. the radula in intrageneric systematics, and (3) differences of opinion on the subspecies concept. © 2005 The Linnean Society of London, Zoological Journal of the Linnean Society, 2005, 144 , 229?260.     

A molecular approach to the phylogenetic relationships of the western palaearctic Helicoidea (Gastropoda: Stylommatophora)

Molecular phylogenetic relationships among 45 members of the Helicoidea (Gastropoda: Stylommatophora) were examined using partial mitochondrial 16S rRNA sequences. Phylogenetic relationships were inferred using maximum parsimony, maximum likelihood and Bayesian methods. The reconstructed phylogenies showed a good degree of support for more recent branches, but gave little support to deeper nodes. Mitochondrial rDNA data further confirmed monophyletic status of helicids, recognized monachine hygromiid and bradybaenid clades and resolved a number of relationships in the helicelline hygromiids. With the respect to the latter assemblage, most of the anatomically based groups are confirmed, corroborating the diagnostic value of the dart-sac complex and a close affinity between Ichnusomunda sacchii and species of the genus Cernuella . Nevertheless, some well resolved branches challenge previous systematic arrangements, grouping species previously placed in different arrangements. In particular, support was not found for the monophyly of helicelline hygromiids with pedal penial innervation. Possible explanations for these incongruencies are suggested. 16S sequence data are appropriate for studies of relationships within the different species groups and less so for recovery of more ancient radiations in the Helicoidea. It will be valuable to combine the 16S data with other gene sequences to estimate basal relationships.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 501–512.     

Type materials of the species of the Planorbidae (Mollusca,Gastropoda, Hygrophila) described by Shuichi Mori

ABSTRACT

The planorbid species that were described by Shuichi (Syuiti) Mori from Japan have long been enigmatic and their taxonomy has been highly confused. This situation is also an impediment to action for the conservation of Japanese planorbids which are one of the most threatened freshwater snail groups in the country. Based on our examination of Shuichi Mori’s collection stored in the Kyoto University Museum, type materials of the taxa described by him are re-illustrated and re-examined for the first time. Our examination suggested that Gyraulus amplificatus (Mori, 1938) is not a morphological form of Gyraulus biwaensis but a distinct species. Gyraulus pulcher (Mori, 1938) can be regarded as a junior synonym of Gyraulus chinensis.