The phylogeny and taxonomy of austral monodontine topshells (Mollusca: Gastropoda: Trochidae), inferred from DNA sequences

The systematics of topshells (family Trochidae) is currently unresolved: at present even the generic boundaries within this group are poorly defined. In this study, we used sequence data of two mitochondrial genes (16S and cytochrome oxidase 1, COI) and one nuclear gene (actin) to resolve the phylogeny of a closely related subgroup of the Trochidae, 30 species of largely Southern Hemisphere monodontine topshells. The phylogenies constructed revealed five well-supported generic clades: a South African clade (genus Oxystele Philippi, 1847), which lay basally to four internal Pacific clades (genera Chlorodiloma Pilsbry, 1889; Monodonta Lamarck, 1799; Austrocochlea Fischer, 1885; and Diloma Philippi, 1845). The molecular phylogenies constructed in this study shed light on previously unresolved relationships between different groups of topshells, allowing for the first time assignation (based on DNA sequence) of clearly defined, well-supported taxonomic and nomenclatural classification of monodontine topshells species. Austrocochlea crinita (Philippi, 1849), A. odontis (Wood, 1828), A. adelaidae (Philippi, 1849), and A. millelineata (Bonnet, 1864) are placed in the genus Chlorodiloma, which we resurrect from synonymy with Austrocochlea. The Japanese M. confusa Tapparone-Canefri, 1874 is treated as a separate species from M. labio (Linné, 1758). Melagraphia Gray, 1847 is synonymised with Diloma and its sole member, M. aethiops (Gmelin, 1791), along with A. concamerata (Wood, 1828), is transferred to that genus. The Juan Fernandez endemic D. crusoeana (Pilsbry, 1889) is synonymised with D. nigerrima (Gmelin, 1791). We find that morphologically cryptic species are not necessarily close genetically.     

Host specificity of ambrosia and bark beetles (Col., Curculionidae: Scolytinae and Platypodinae) in a New Guinea rainforest

Abstract.  1. Bark and ambrosia beetles are crucial for woody biomass decomposition in tropical forests worldwide. Despite that, quantitative data on their host specificity are scarce.
2. Bark and ambrosia beetles (Scolytinae and Platypodinae) were reared from 13 species of tropical trees representing 11 families from all major lineages of dicotyledonous plants. Standardised samples of beetle-infested twigs, branches, trunks, and roots were taken from three individuals of each tree species growing in a lowland tropical rainforest in Papua New Guinea.
3. A total of 81 742 beetles from 74 species were reared, 67 of them identified. Local species richness of bark and ambrosia beetles was estimated at 80–92 species.
4. Ambrosia beetles were broad generalists as 95% of species did not show any preference for a particular host species or clade. Similarity of ambrosia beetle communities from different tree species was not correlated with phylogenetic distances between tree species. Similarity of ambrosia beetle communities from individual conspecific trees was not higher than that from heterospecific trees and different parts of the trees hosted similar ambrosia beetle communities, as only a few species preferred particular tree parts.
5. In contrast, phloeophagous bark beetles showed strict specificity to host plant genus or family. However, this guild was poor in species (12 species) and restricted to only three plant families (Moraceae, Myristicaceae, Sapindaceae).
6. Local diversity of both bark and ambrosia beetles is not driven by the local diversity of trees in tropical forests, since ambrosia beetles display no host specificity and bark beetles are species poor and restricted to a few plant families.     

Testing the trend towards specialization in herbivore-host plant associations using a molecular phylogeny of Tomoplagia (Diptera: Tephritidae)

Herbivorous insects are abundant and diverse and insect-host plant associations tend to be specialized and evolutionarily conserved. Some authors suggested that generalist insect lineages tend to become specialists, with host specialization leading to an evolutionary dead-end for the parasite species. In this paper, we have examined this tendency using a phylogenetic tree of Tomoplagia (Diptera: Tephritidae), a parasite of asteracean plants. We have tested the trend towards specialization in different hierarchical degrees of host specialization. The topology of the tree, the inference of ancestral hosts, and the lack of directional evolution indicated that specialization does not correspond to a phylogenetic dead-end. Although most Tomoplagia species are restricted to a single host genus, specialization does not seem to limit further host range evolution. This work emphasizes the advantages of the use of different levels of specialization and the inclusion of occasional hosts to establish a more detailed scenario for the evolution of this kind of ecological association.     

Staphylorchis cymatodes (Gorgoderidae: Anaporrhutinae) from carcharhiniform, orectolobiform and myliobatiform elasmobranchs of Australasia: Low host specificity, wide distribution and morphological plasticity

Anaporrhutine gorgoderids (Digenea: Gorgoderidae: Anaporrhutinae) found in the body cavity of six species of elasmobranchs from the orders Carcharhiniformes, Myliobatiformes and Orectolobiformes from Australian waters were found to belong to the genus Staphylorchis. Although these specimens were morphologically variable, sequences of ITS2 and 28S ribosomal DNA from specimens from three host families and two host orders were identical. Based on morphological and molecular data these specimens were identified as the type-species of the genus, Staphylorchis cymatodes. New measurements are provided for S. cymatodes, and for the first time genetic data are presented for this species. In addition to providing new morphological and molecular data for S. cymatodes, the previously described species S. gigas, S. parisi and S. scoliodonii, are here synonymised with S. cymatodes. This implies that S. cymatodes, as conceived here, has remarkably low host-specificity, being recorded from eight elasmobranch species from four families and three orders, has a wide geographical distribution in the Indo-west Pacific from off India, in the Bay of Bengal, to Moreton Bay in the Coral Sea, and is morphologically plastic, with body size, size of specific organs and body shape differing dramatically between specimens from different host species. The genus Staphylorchis now contains only two valid species, S. cymatodes and S. pacifica.     

Examining the phylogeny of the Australasian Lymnaeidae (Heterobranchia: Pulmonata: Gastropoda) using mitochondrial, nuclear and morphological markers

We examined the species groups relationships of the freshwater snail genus Austropeplea using mitochondrial, nuclear and morphological markers in addition to traditional methods of shell shape analysis. Based primarily on the results of a combined molecular and morphological analysis, samples of the nominal species A. tomentosa form distinct lineages. The New Zealand populations of A. tomentosa are a very distinct lineage from any of the Australian populations attributed to A. tomentosa. Furthermore, within the Australian group, three lineages, south Australia, Tasmania and eastern Australia, appear to have undergone recent and/or rapid speciation events. Samples assigned to A. lessoni were resolved as two distinct lineages, representing the eastern and northern Australian populations. Kutikina hispida was resolved within the Australian A. tomentosa clade. Molecular results for A. viridis suggests that it is also composed of at least two distinct lineages that could be treated as species. Incongruence observed between the single mitochondrial, nuclear and morphological topologies highlight the importance of using a number of different datasets in the delimitation of species-group taxa.     

New Macroderoides (Digenea: Macroderoididae) from Florida gar, with molecular phylogeny of the genus

Macroderoides minutus n. sp. is described based on specimens collected from the Florida gar (Lepisosteus platyrhincus) from Orange Lake, Alachua County, Florida. The new species is the ninth recognized species of Macroderoides and is morphologically closest to Macroderoides flavus and Macroderoides typicus. It differs from both species in having a smaller body, ventral sucker larger than the oral sucker, substantially lower body length to width ratio, fewer and larger eggs, and other characters. A comparison of sequences of nuclear rDNA (partial 18S, complete ITS region, and partial 28S) of the new species, with sequences of 5 other Macroderoides, convincingly supports the status of M. minutus as a new species. Molecular phylogenetic analysis, including all North American Macroderoides species except for Macroderoides parvus, has demonstrated the presence of 2 distinct clades, 1 including Macroderoides spinifer + (Macroderoides minutus n. sp. + Macroderoides texanus) and the other including Macroderoides trilobatus + (M. typicus + M. flavus). The tree topology suggests that the similarity in body proportions among M. minutus n. sp., M. typicus + M. flavus is not a result of close phylogenetic relationship. It has also revealed for the first time the phylogenetic affinities of M. flavus, which is the only North American member of Macroderoides that switched from holostean fishes to teleosts.     

Molecular phylogenetics of Triculine snails (Gastropoda: Pomatiopsidae) from southern China

Triculine (Gastropoda: Rissooidea: Pomatiopsidae) snails are involved in the transmission of schistosomiasis and paragonimiasis; their distributions are mainly across southeastern Asia and southern China. In the present investigation, partial sequences of COI, 16S, and 28S were examined to infer the phylogenetic relationships among the species rich and poorly understood gastropod. Samples were collected from 12 geographic locations in six provinces of southern China. Several methods such as maximum parsimony, maximum likelihood and distance analysis were used in phylogenetic analyses among these taxa. The resultant phylogenetic trees showed a similar topology irrespective of the phylogenetic methods used. The taxa fell into two clades, with those from Fujian, Guangxi, and Zhejiang Provinces in one clade and those from Hunan, Sichuan and Hubei in the other. Among the taxa in Hubei Province, five formed a monophyletic clade, but Tricula sp. H-SHY fell into a sister clade of Tricula hortensis of Sichuan, whilst Tricula hongshanensis formed a single clade. Sister taxa Tricula pingi and Tricula hsiangi formed well-supported clade within almost all the trees. These results, while preliminary, represent the first attempt to reconstruct a phylogeny for Triculinae across China.     

Molecular phylogeny of Australian Helicarionidae, Euconulidae and related groups (Gastropoda: Pulmonata: Stylommatophora) based on mitochondrial DNA

The delineation and phylogenetic relationships of the pulmonate family Helicarionidae are currently poorly understood. We have undertaken a phylogenetic analysis of Australian members of Helicarionidae. Three consecutive mitochondrial genes (COI, tRNA-val and 16S rRNA) were sequenced for 36 species from Helicarionidae and related groups. Helicarionidae grouped with Ariophantidae and Urocyclidae with good support in all trees, as did Microcystinae with Trochomorphidae, corresponding to the results of a previous morphological study, but the relationships of Euconulinae and Limacidae could not be resolved. Cystopeltidae never grouped with Helicarionidae and should be regarded as a separate family. The position of tRNA-val in the mitochondrial genome provided a new synapomorphy for Microcystinae. In addition, the COI and 16S rRNA sequences showed a high degree of compositional heterogeneity and incompatibility of phylogenetic signals, highlighting the importance of testing for the decay of the historical signal prior to the phylogenetic analysis.     

Speciation in ancient cryptic species complexes: evidence from the molecular phylogeny of Brachionus plicatilis (Rotifera)

Continental lake-dwelling zooplanktonic organisms have long been considered cosmopolitan species with little geographic variation in spite of the isolation of their habitats. Evidence of morphological cohesiveness and high dispersal capabilities support this interpretation. However, this view has been challenged recently as many such species have been shown either to comprise cryptic species complexes or to exhibit marked population genetic differentiation and strong phylogeographic structuring at a regional scale. Here we investigate the molecular phylogeny of the cosmopolitan passively dispersing rotifer Brachionus plicatilis (Rotifera: Monogononta) species complex using nucleotide sequence variation from both nuclear (ribosomal internal transcribed spacer 1, ITS1) and mitochondrial (cytochrome c oxidase subunit I, COI) genes. Analysis of rotifer resting eggs from 27 salt lakes in the Iberian Peninsula plus lakes from four continents revealed nine genetically divergent lineages. The high level of sequence divergence, absence of hybridization, and extensive sympatry observed support the specific status of these lineages. Sequence divergence estimates indicate that the B. plicatilis complex began diversifying many millions of years ago, yet has showed relatively high levels of morphological stasis. We discuss these results in relation to the ecology and genetics of aquatic invertebrates possessing dispersive resting propagules and address the apparent contradiction between zooplanktonic population structure and their morphological stasis.     

The evolution of social behaviour in sentinel crabs (Macrophthalmus): implications from molecular phylogeny

Crabs of the genus Macrophthalmus are known to exhibit highly developed and diverse social behaviour, such as allocleaning, fighting and waving display behaviour, the first being observed widely throughout the genus. Fighting behaviour between males has been classified previously into grasping fighting and claw‐extending fighting, and male waving display into four patterns, the vertical non‐forward‐pointing type, vertical forward‐pointing type, lateral non‐forward‐pointing type and lateral forward‐pointing type, on the basis of interspecific behaviour comparisons. To understand the evolutionary pathways of these social behavioural activities, 978‐bp nucleotide sequences from mitochondrial 16S rRNA genes of 21 species, including two outgroup taxa, were analysed and a molecular phylogeny was reconstructed. The resultant tree demonstrated striking inconsistencies with the relationships inferred from morphological features. Species with similar habitat conditions showed similar morphological features, although they were not phylogenetically close relatives. Phylogenetic analysis of allocleaning behaviour suggested that it evolved once in the early history of the lineage. The analysis of fighting behaviour demonstrated that species with claw‐extending fighting, being a more complex behaviour than grasping fighting, are found in the most ancestral part of the phylogeny. The analysis also revealed that claw‐extending fighting has evolved secondarily on two occasions, suggesting that fighting behaviour is not characterized by sufficient phylogenetic components. The superimposition of a waving pattern on to the phylogeny indicated that the lateral non‐forward‐pointing type has evolved from the vertical non‐forward‐pointing type, the lateral forward‐pointing type having evolved from the vertical forward‐pointing type. This scenario also appeared reasonable with respect to the behavioural trends of cheliped movements in waving. © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 88 , 45–59.     

New records of Conidae (Mollusca: Gastropoda) from the New Zealand region

Abstract

Conus howelli Iredale is recorded from New Zealand. C. howelli and C. raoulensis Powell are considered to be very closely related, and Kermasprella Powell is thus probably a svnonvm of Endemoconus Iredale. C. teramachii (Kuroda) and C. smirna Bartsch ' Rehder are recorded from off northern New Zealand, and the known range of C. kermadecensis Iredale is extended southward.     

Molecular phylogeny and character evolution in the Western Palaearctic Helicidae s.l. (Gastropoda: Stylommatophora)

In this study, we present a molecular phylogeny for the west Palaearctic Helicidae sensu lato based on sequence data from two mitochondrial (COI, 16S rDNA) and two nuclear (ITS-1, 18S rDNA) genes. Maximum likelihood analysis and Bayesian inference revealed well supported monophyletic clades partly conflicting traditional classifications. Based on these results, we propose the following system. The Western Palaearctic Helicidae s.l. consist of two families, Helicidae and Hygromiidae. Within the Helicidae, three well supported subfamilies can be recognised: the Helicinae, Ariantinae, and Helicodontinae. The Hygromiidae consist of three clades: the Hygromiinae, the Helicellinae, and a yet unnamed clade comprising the genera Sphincterochila and Cochlicella. We then used the phylogeny to study the evolution of anatomical, and ecological characters traditionally used for systematic classification. In the Helicidae s.l., two independent evolutionary transitions to life in xeric environments occurred, which allowed the occupation of new niches with a subsequent radiation of the Helicellinae-Cochlicella/Sphincterochila clade and the Helicinae. Whereas, the multiplication of the Glandulae mucosae is a synapomorphy of the Hygromiidae, the lovedart sac apparatus is present in all groups and thus, the trait cannot provide a synapomorphy for either families or subfamilies. Additionally, we evaluated the use of structural molecular genetic characters for taxonomic assessment. The presence of an unique loop region of the 16S rDNA gene and a short tandem repeat in the ITS-1 region provide independent evidence for the monophyly of these major two groups, and can be used for preliminary classification.     

Molecular phylogeny of the genus Philodendron (Araceae): delimitation and infrageneric classification

The genus Philodendron (Araceae) is a large neotropical group whose classification remains unclear. Previous classifications are based on morphological characters, mainly from the inflorescence, flower and leaf shape. The classification by Krause, with few modifications, is still the most commonly used system. To examine phylogenetic relationships in the genus, two ribosomal DNA nuclear markers, internal transcribed spacer (ITS) and external transcribed spacer (ETS), and the chloroplast intron rpl 16, were sequenced and analysed for more than 80 species of Philodendron and its close relative Homalomena . According to the resulting phylogeny, the genus Homalomena may be paraphyletic to the genus Philodendron . The inclusion of the American Homalomena species within the genus Philodendron might resolve this taxonomic problem. All three subgenera of Philodendron were revealed as monophyletic. Below the subgeneric level, the groups obtained in our phylogeny globally correspond to sections recognized in previous classifications. Among the morphological characters used by previous taxonomists to build their classifications, and which we optimized onto one of the most parsimonious trees, most characters were found to be homoplasious. However, leaf shape, characteristics of the sterile zone on the spadix and venation patterns are useful for delimiting subgenera and sections within the genus.  © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 156 , 13–27.     

Recent and Tertiary Seguenziidae (Mollusca: Gastropoda) from the New Zealand region

Abstract

The family Seguenziidae is represented in the New Zealand region by the following new species (fossil taxa asterisked): Seguenzia glabella*, S. prisca*, S. serrata*, S. conopia, S. fulgida, S. chelina, S. transenna, S. textilis, S. compta; Seguenziella (n.gen.) patula; Seguenziopsis (n.gen.) bicorona; Carenzia venusta, C. fastigiata; Thelyssina (n.gen.) sterrha; Ancistrobasis dilecta, A. regina; Fluxinella (n.gen.) lepida, F. lenticulosa, F. maxwelli*; Calliobasis (n.gen.) eos*, C. chlorosa, C. miranda.     

Re-discovery and novel contributions to morphology and multigene phylogeny of Protospirella mazurica (Raabe, 1968) Aescht, 2001 (Ciliophora: Pleuronematida), an obligate symbiont of the river nerite Theodoxus fluviatilis Linnaeus, 1758 (Mollusca: Gastropoda)

Although the river nerite Theodoxus fluviatilis (Gastropoda: Neritimorpha) has an exceptionally broad geographical and ecological distribution, it carries only four ciliate species: Hypocomella quatuor, Protospirella mazurica, Scyphidia sp., and Trichodina baltica. After more than a half-century gap, we re-discovered P. mazurica in a Danubian population of T. fluviatilis (haplotypes F31 and F34) and characterized it using an integrative morpho-molecular approach. Protospirella mazurica is distinguished by (i) a small, elongate-ellipsoidal to ovoidal body, (ii) a broadly ellipsoidal macronucleus accompanied by a single globular micronucleus, (iii) a subterminal contractile vacuole, (iv) about 24 somatic kineties, (v) thigmotactic ciliature composed of about 10 kineties shortened posteriorly to form a parenthetical system, and (vi) a long inverted J-shaped paroral membrane associated with three unequally long membranelles. According to the present phylogenetic analyses of two mitochondrial and three nuclear markers, P. mazurica robustly clusters within the order Pleuronematida (Oligohymenophorea: Scuticociliatia) along with other symbiotic members of the families Hemispeiridae and Thigmophryidae as well as free-living representatives of the paraphyletic family Cyclidiidae. In light of the present phylogenetic analyses, we consider the family Ancistridae to be a junior synonym of the family Hemispeiridae, which collates 14 genera in our classification framework.     

Taxonomy, host specificity and dietary implications of Hurleytrematoides (Digenea: Monorchiidae) from chaetodontid fishes on the Great Barrier Reef

Five new and five previously described species of Hurleytrematoides are reported from 19 of 34 chaetodontid species examined from the Great Barrier Reef; new species are H. faliexae n. sp., H. galzini n. sp., H. loi n. sp., H. morandi n. sp., and H. sasali n. sp. Previously described species are H. coronatum, H. fijiensis, H. prevoti, H. bartolii, and H. zebrasomae. The genus is rediagnosed in the light of morphological variation of the new species; the degree of spination and shape of the terminal genitalia distinguish individual species. Species of Hurleytrematoides infect almost every clade of the family Chaetodontidae found on the Great Barrier Reef, but obligate corallivores are not infected. All ten species were found at Heron Island on the southern Great Barrier Reef, but only six at Lizard Island on the northern Great Barrier Reef. For three of the four species not present at Lizard Island, the absence appears to be statistically significant. Although all species are apparently restricted to chaetodontids on the GBR, specificity within the family varies from oioxenous to euryxenous; a core/satellite host paradigm explains the distribution of several species.     

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.