Monday, June 13, 2005

ENV: AMS Abstracts

Here are the abstracts from the American Malacological Society meetings to be held this month. Unfortunately i won't be able to attend, but here's the sessions i would most like to attend. This is an excerpt of papers that concern species of North American freshwaters and landmasses and other groups with which i work. Thanks to Aydin for the heads up via the Malacological listservs -- he's been posting portions of his paper on his own blog at Snail's Tales. You can access the entire set of abstracts at:

http://zeus.calacademy.org/WSM/documents/Abstract_volume-03.html


Results of the giant pacific octopus census in Puget Sound, 2000-2005
Roland C. Anderson
The Seattle Aquarium

A scuba diving survey was organized on 19 February 2000 by the Seattle Aquarium in Puget Sound (Washington State, USA) to establish a baseline of how many giant Pacific octopuses (Enteroctopus dofleini) there were in the area and to determine if the population was healthy. Information requested from the volunteer divers was location, depth, time, description of dens, and an estimate of size. There were 18 octopuses spotted that day by 114 divers looking at 19 popular dive sites where octopuses had been seen historically. Four octopuses were females guarding eggs. Since then, the census was increased to the three days of the holiday weekend with increased participation and increased octopus sightings. In 2005 210 divers reported seeing 61 octopuses, none in southern Hood Canal. Implications of the results of this census in relation to behavior, life history, and biology of these octopuses, environmental changes, presence of marine preserves and possible harvest limits are discussed.

Extinction and the life history of unionid bivalves
Chris Barnhart
Department of Biology, Southwest Missouri State University, 901 S. National Ave., Springfield, MO 65804

Freshwater mollusks are disproportionately represented among recent extinctions. In North America, estimates of historical extinctions of freshwater bivalves (Unionidae) range from 21-37 species, or about 10% of the pre-settlement fauna. Many more extinctions are impending. Reasons for this decline are complex and mainly involve anthropogenic habitat destruction and fragmentation. The dependence of unionids on particular species of fish as hosts for parasitic larva development is an unusual example of “habitat” specialization that may contribute to vulnerability and that complicates efforts to define diversity and conservation priorities. Recent studies of host specificity indicate that some morphologically defined unionid species consist of multiple species or at least host races, which are differentiated by their adaptation to sympatric host fish species and populations. Such differentiation is expected to be most pronounced in mussels that utilize geographically fragmented and genetically diverse host populations. In the unionid morphospecies Cyprogenia aberti, for example, mussel populations in different drainages are able to utilize local populations of several species of darters (Etheostoma, Percina) but generally not populations or species from other drainages. Both host specificity and genetic evidence indicate that C. aberti consists of 3-4 species. Reliance on particular host species or populations probably increases extinction risks for unionids because they share vulnerabilities of the host species as well as their own. However, the hypothesis that host abundance, host genetics, or particular aspects of the host-parasite relationship are responsible for unionid declines is generally untested.

Molecular systematics of problematic unionids
David C. Campbell
Biodiversity and Systematics, 425 Scientific Collections, Department of Biological Sciences, University of Alabama, Box 870345, Tuscaloosa AL 35487-0345, amblema@bama.ua.edu

The combination of high ecophenotypic variation, geographic variation, and rarity in many unionid species have contributed to uncertainty about their systematics. Use of DNA sequencing of the ITS1, cox1, 16S, and nadh1 regions reveal that Lasmigona holstonia as currently recognized is a species complex, with Coosa and Caney Fork system populations both distinct from the Tennessee and New populations. Recognition of species in Toxolasma and Elliptio has ranged from extreme splitting to extreme lumping; molecular data support an intermediate level of species diversity. “Obovaria” olivaria appears relatively distinct from other “Obovaria” species, in agreement with Simpson's recognition of a distinct genus for it. Fusconaia species show strong biogeographic patterns in their distribution; relationships within the flava-cerina-askewi complex remain unclear. Frequent genetic differentiation of populations from different river systems suggests that geographically isolated populations of supposedly widespread species deserve close scrutiny.

North American Physidae (Pulmonata: Basommatophora) - a new perspective on reproductive characters
Stephanie A. Clark1 and Ellen E. Strong2
1Department of Biodiversity & Systematics, School of Biological Sciences, University of Alabama, PO Box 870345, Tuscaloosa, AL 35487, U.S.A., ; 2Department of Invertebrate Zoology, Smithsonian Institution, National Museum of Natural History, Washington DC, 20560, USA


The family Physidae Fischer & Crosse 1886 is a group of freshwater hermaphroditic gastropods with a primarily Holarctic distribution. Although it extends into Central and South America, North America represents the center of diversity for the family, where they are ecologically important members of communities particularly in lentic habitats.

The classification of the Physidae is currently unstable. Over the last century, this classification has been based primarily on a combination of shell and male reproductive characters, culminating in George Te's 1980 classification that relied almost exclusively on features of the penial complex. This scheme was further refined by Dwight Taylor in 2003. Like Te, Taylor's classification is based almost entirely on the penial complex.

However, the incorporation of morphological data into physid classification schemes has been accomplished in the absence of precise character definitions, relying instead on vague notions of penial complex groupings and assumptions of polarity of these characteristics. This hinders efforts to test hypotheses of penial complex evolution and assess the hierarchical level at which discrete changes in penial complex characters are informative. Detailed anatomical studies of both the male and female reproductive systems, including serial histological sections, has revealed an array of new characters and allowed the formulation of discrete character/character state definitions. When these characters are mapped on a recently produced phylogeny of North American physids based on two mitochondrial genes (16S, COI), new insight is shed on the evolution of the penial complex across this clade. Implications for the current classification will be discussed.

Partulids on Tahiti: an interesting distribution among surviving populations
Trevor Coote and Walter Teamotuaitau
Partulid Fieldwork Programme Consortium, B.P.2407, Papeete, Tahiti, French Polynesia; partula2003@yahoo.co.uk

The extinction of numerous species of endemic land snails in French Polynesia due to the introduction of the carnivorous Euglandina rosea is a salutary lesson in panic biological control undertaken without adequate scientific field trials. Less than 20 of the original 70+ species of the family Partulidae survive on maybe a dozen of the original 17 islands which were previously host to partulids. Last year surveys were carried out in over 60 of the valleys of Tahiti. All of the populations found were of the Partula hyalina/clara sister lineage which previously accounted for only 5-10% of the individuals collected in scientific studies before the introduction of E. rosea. No individuals of the Partula otaheitana/affinis complex were found (over 90% of previous collections) in any valleys, yet these species still survive in many montane forest areas (over 1000 m altitude). Partula nodosa, with a previous distribution of just 7 valleys, is most likely extinct in the wild but persists well in captive populations. Partula filosa, Partula producta, and Partula cytherea (all previously with a single valley distribution) are almost certainly extinct, as are Samoana jackieburchi and Samoana burchi. Samoana attenuata, also surviving on Moorea, is very rare but widely distributed.

Predation by Euglandina rosea on local versus non-local gastropods: no differences in mucus trail following?
Elizabeth C. Davis
Department of Ecology and Evolutionary Biology, University of Kansas, Lawrence, KS 66045-7534, USA

Carnivorous snails, such as Euglandina rosea, have been used unsuccessfully as biocontrol agents in Hawaii and other Pacific islands in an attempt to control the giant African land snail, Achatina fulica. Euglandina rosea is native to the Southeastern United States, and is able to follow the mucus trails of its prey. Although there have been experiments on food choice, it is not known if the ability of Euglandina rosea to follow mucus trails differs with snail pray species. This study compared the ability of E. rosea to follow trails of two groups of gastropods: those found within its local habitat (Southeastern USA) and those not found within its native range (Kansas). Each predator (n = 10) was tested against eight species of gastropods (four species from each area) and three individuals of each species. The results of the study indicate that a high level of individual variation of predator behavior, and that gastropods from Florida and Kansas were followed at almost the same frequency by the ten predators tested.

Preliminary Report of the Terrestrial Molluscan fauna of the Eastern Caribbean Islands, and Trinidad & Tobago
H. Angela Fields1 & David G. Robinson2
1Department of Biological & Chemical Sciences, University of the West Indies, Cave Hill, Barbados ; 2 USDA APHIS PPQ / Academy of Natural Sciences, Philadelphia, PA 19103, USA

The islands of the Eastern Caribbean, with the exception of Barbados, are part of an island arc system that stretches from Sombrero in the north to Grenada in the south. There is an inner volcanic arc of mountainous islands, and an outer arc of limestone islands, representing an older, submerged volcanic chain. The relative age, relief, geology, rainfall patterns, and forest cover on the islands have resulted in a wide variety of environments. In contrast, Trinidad and Tobago were once part of the South American continent, and share the tectonic history of northern Venezuela. All of these islands have suffered large-scale modification of their original environments as a result of colonial occupation and more recently increasing population densities. Between 2002 and 2005, twenty-one islands so far were visited and their malacofauna surveyed. The faunas found are quite diverse with surprising levels of endemicity on some islands, with at least sixteen endemic species on Dominica and at least one endemic on most of the other islands. Revisions of some snail groups have become necessary with a number of new species that are now being described, and some “lost” species have been re-discovered. Invasive taxa are established on many islands and are an increasingly pervasive component of their malacofauna.


Progress in the conservation of Hawaiian Achatinelline snails
Michael G. Hadfield
Kewalo Marine Laboratory, University of Hawaii, 41 Ahui St., Honolulu, HI 96813

Hawaii's ~750 species of endemic terrestrial and arboreal snails have experienced great extinction, among the most severely impacted being members of the subfamily Achatinellinae. Efforts over the last 30+ years to understand the causes of extinction, to monitor the survival of species, and to conserve what remains of this spectacular radiation (~100 spp. in 4 genera) include field-demographic studies of populations on four islands, monitoring a population of one species within a predator exclosure, captive propagation, and population-genetic studies. The O`ahu-endemic genus Achatinella has diminished from 41 species to about 9 at the present, 7 of them represented among the 1,500 achatinelline snails from three genera in the tree-snail laboratory. By monitoring climatic conditions in the field, we were able to establish “climates” in environmental chambers that have encouraged population-growth demographics comparable to field populations for most species. For others, species that seemingly live in almost identical field situations, laboratory propagation is far less successful. Sample data for lab populations include original (field-collected) vs. current numbers as follows: A. fuscobasis, 11/440; A. decipiens, 12/38; A. lila, 4/296; and A. apexfulva, 14/12. Molecular genetic studies have been used to guide conservation efforts, in the field and the laboratory, for A. mustelina, a model that will be used for other species as well.

Preliminary phylogenetic assessment of invasive apple snails in Asia and beyond
Kenneth A. Hayes1
1Department of Zoology, University of Hawaii-Manoa, Honolulu, HI 96822, khayes@hawaii.edu

The freshwater apple snail genus Pomacea (family Ampullariidae) has a native range covering most of South and Central America and the southeastern U.S. Pomacea spp. have been introduced widely in southern and eastern Asia, Hawaii and other Pacific islands, and elsewhere in the mainland U.S. In their introduced ranges they have become major pests of wetland crops, notably rice and taro. The taxonomy of Pomacea, including the identity and precise geographic origins of invasive populations, is poorly understood. This lack of understanding has implications for research on many aspects of ampullariid biology, including development of effective pest management programs. As part of a systematic study focusing on the genus Pomacea, I am using DNA sequence data to investigate hypotheses concerning the geographic origins, molecular systematics and genetic diversity of introduced populations. So far, 300 individuals representing at least 11 putative Pomacea species have been analyzed. Preliminary results suggest possible cryptic species among the apple snails that have been introduced to S.E. Asia. These data also suggest multiple independent introductions of the most common invasive apple snail, P. canaliculata, contrary to anecdotal accounts of a single introduction spreading throughout the region. Pomacea canaliculata collected in Hawaii and numerous S.E. Asian locations appears to have originated in Argentina, whereas snails from Thailand and Cambodia are likely to have come from Brazil or elsewhere and may even be a different species. Overall, the results indicate that at least four, possibly more, species of Pomacea have been introduced into southern and eastern Asia.

Species-level Phylogeny and Phylogeography of Conus: A Progress Report
Alan J. Kohn1, Christopher P. Meyer2, and Thomas F. Duda, Jr.3,4
1Department of Biology, University of Washington, Seattle, WA 98195, USA, ; 2Florida Museum of Natural History, University of Florida, Gainesville, FL 32611, USA, ; 3Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109, USA, ; 4Smithsonian Tropical Research Institute, Apartado 2072, Balboa, Ancen, Republic of Panama

Segments of two mitochondrial genes (16S rRNA and COI) of about 150 species of Conus, or more than 25% of the recognized species in the genus, have now been sequenced. We use these data to explore the degree of agreement between species distinguished by morphological and molecular criteria, and to test prior hypotheses of species-level phylogeny and phylogeography based on analyses of smaller samples. For Conus of the Indo-West Pacific region, 16S genetic distances of species recognized on shell morphology generally confirm the prior taxonomic decisions. Increased molecular sampling continues to support the early (probably Late Eocene-Early Oligocene) divergence of two major lineages. The smaller of these, thus far comprising only 16 species, is predominantly distributed in the Eastern Pacific and Western Atlantic regions. The larger major clade, comprising all remaining species, is predominantly Indo-West Pacific but includes representatives of all other geographic regions. Recent analyses emphasizing Western Atlantic species suggest two subsequent radiations, probably during the Miocene. One of these contains 12 Western Atlantic and 3 Eastern Pacific species; the other, 2 Western Atlantic, one amphiatlantic, 5 Eastern Pacific, and a single Indo-West Pacific species. The new results also support our prior hypotheses of monophyly of molluscivorous Conus species and polyphyly of piscivorous species.

Mediterranean Land Snails and Wildfires
Esther Lachman
Department of Evolution, Systematics and Ecology, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel, cookie@pob.huji.ac.il

Wildfires in Mediterranean scrub in Israel occur mainly during the hot, dry summer, when land snails are aestivating. Three common Mediterranean species were investigated following a wildfire (in the Judean Hills, Israel). Euchondrus septemdentatus (inhabits shallow soil pockets) was completely eradicated by the fire and has not has not re-colonized burnt areas to this day (7 years post-fire). Levantina hierosolyma and Buliminus labrosus (crevice-dwellers) survived the fire; their population dynamics were studied for five years in post-fire conditions. Age composition differed between burnt and control plots in L. hierosolyma but not in B. labrosus. In the laboratory L. hierosolyma was found to be well adapted to the dry conditions prevalent following wildfires. Its normothermic water loss rate (only 5% in 21 days) is the lowest ever recorded for a Mediterranean land snail. When L. hierosolyma was exposed to combinations of high temperatures (50-1000C) and time periods (5-120 minutes) in the laboratory it survived exposures of up to 20 minutes at 600C (14% survival) and 5 minutes at 750C (100%). Longer exposures at 750C or higher temperatures (1000C) resulted in 100% mortality. Of the three species, B. labrosus seems to be the least affected both by fire and post-fire conditions. L. hierosolyma populations are affected by the fire, but laboratory results suggest they are at an advantage in the dry conditions prevailing in the wake of wildfires. E. septemdentatus does not survive and does not re-colonize burnt areas, even when reintroduced, indicating it is unable to adapt to post-fire conditions.

A combined analysis of the phylogeny of Cephalopoda
Annie Lindgren1 and Frank Anderson2
1Department of Evolution, Ecology and Organismal Biology, The Ohio State University, Columbus, OH 43212 ; 2Department of Zoology, Southern Illinois University, Carbondale, IL 62901

This study provides a comprehensive phylogenetic analysis of Cephalopoda using molecular and morphological data. Regions of four molecular loci (nuclear 18S rRNA, 28S rRNA, histone H3, and mitochondrial cytochrome c oxidase subunit I) were combined with 101 morphological characters to test interfamilial relationships of sixty cephalopod taxa, with emphasis on the families within Decabrachia (“squids”, cuttles and their allies). Individual molecular and combined data sets were analyzed using the direct optimization method (with parsimony as the optimality criterion) and partitioned Bayesian methods. Monophyly of Cephalopoda, Nautiloidea, Neocoleoidea (all extant cephalopods except nautiluses) and Decabrachia was supported by most analyses; however, monophyly of Octobrachia (octopuses) was falsified due to a lack of support for Cirroctopoda + Octopoda in some trees. Vampyromorpha (vampire squids) was found to be sister to Decabrachia (rather than Octobrachia) in both combined molecular and total evidence analyses. Within Decabrachia, support was found for a relationship between the sepioid orders Idiosepiida, Sepiida (true cuttles), Sepiolida and the teuthid family Loliginidae, rendering the order Teuthida polyphyletic. We believe that the rooting of the neocoleoid portion of the tree, the phylogenetic position of Vampyromorpha and the possible paraphyly of Octobrachia merit further investigation.

Changes in the Mussel Community of Ohio Brush Creek
Stephen F. Matter1, Francisco J. Borrero1,2, and Chris Bedel1
1Cincinnati Museum Center at Union Terminal, 1301 Western Ave., Cincinnati, OH 45203, USA; 2Cincinnati Country Day School, 6905 Given Rd., Cincinnati, OH 45243

We evaluated the status of the mussel community of Ohio Brush Creek and its tributaries in southeastern Ohio over a 17 year period. This stream has harbored one of the most diverse mussel communities in the region, with 39 of the 76 species recorded for the entire state of Ohio. Species richness increased to 23 in 2004, from 16 and 20 species found in 1996 and 1987, respectively. Despite the increase in species number, the abundance of live and freshly dead shells declined, particularly for abundant species. Community structure has changed from one dominated by a few abundant species to a more evenly distributed community composed of a greater number of species with lower abundances. More detailed study of the mussel community of Ohio Brush Creek is warranted. Ongoing mark-recapture work combined with size class structure will provide information to assess whether changes in abundance are due to adult survivorship, recruitment, or are simply a reflection of variability in population size and sampling. In addition, analysis of the health of fish host populations and mapping of substratum types available to mussels will allow ascertaining potential factors affecting the mussel community. At this time, large scale factors, rather than localized disturbance appear to be responsible for the observed changes in diversity and abundance of mussels.

Mexican Holospirinae in review (Gastropoda: Urocoptidae)
Elizabeth L. Mihalcik1 and F. G. Thompson2
1Department of Arts and Sciences, Bainbridge College, Bainbridge GA 39819, ; 2Florida Museum of Natural History, University of Florida, Gainesville, FL, 32711

The subfamily Holospirinae range from the southwestern states of Arizona, New Mexico and Texas to southern Mexico. Within the area of Puebla and immediately adjacent states, 28 species are recognized of which 14 are new. Twelve species groups of Holospira are recognized within the subgenus Holospira within the study area. Within the subgenus Stalactella, five species are recognized. The genus Holospira is much more widespread then Stalactella which is confined to Puebla and Oaxaca. They are found in submesic and xeric habitats of limestone or dolomite substrata. Colonies of snails are limited to proximal outcrops. Prior literature poorly described morphological features for species identification. This study uses shell morphology including internal lamellae, radula, and soft anatomy to differentiate between species-groups. The internal lamellae are serve as a predator barrier and characterize each group. The internal lamellae are represented by typically four lamellae; basal, columellar, palatal, and parietal. Some species-groups like H. melea, H. hogeana, H. fortisculpta, H. scololaema, and H. haploplax have a reduced number of lamellae. The species-groups that have the characteristic four internal lamellae vary greatly in shape between them. The four lamellae stage is considered to be the ancestral condition and evolution of some groups occurred through loss of lamellae. This statement is based on the oldest known fossil of Holospira as well as the general occurrence of four lamellae throughout the range of the genus.

The diversification of the family Enidae in Turkey: an evolutionary perspective
Aydin Orstan1 and M. Zeki Yildirim2
1Section of Mollusks, Carnegie Museum of Natural History, 4400 Forbes Ave., Pittsburgh, PA, 15213 USA, ; 2Süleyman Demirel Üniversitesi, Burdur Eğitim Fakültesi, 15100, Burdur, Turkey

The range of the pulmonate family Enidae, with about 70 genera, extends from Japan across Asia, Middle East, Europe and North Africa to the Azores. Twenty-four genera with close to 90 species have been recorded from Turkey, indicating that a significant diversification of the family has taken place on the land masses that now comprise Turkey. Our ongoing revisions of the Turkish taxa are aimed at developing a more accurate phylogeny and a better understanding of the evolutionary history of these snails. Several conchologically similar genera found in Turkey differ anatomically (for example, Mastus, Paramastus, Borlumastus, Ena, Merdigera, Megalena), while many congeneric species are difficult to distinguish anatomically (for example, Mastus species, Jaminia species). When anatomical and conchological characteristics are taken together some generalizations are beginning to emerge. We are also creating high resolution distribution maps that are expected to offer a better understanding of not only the current ecology of these snails but also the past speciation events.

Identifying the Pupilloids Gastrocopta pentodon and G. tappaniana on the Delmarva Peninsula, Eastern USA
Timothy A. Pearce
Carnegie Museum of Natural History, 4400 Forbes Ave., Pittsburgh, Pennsylvania 15213, USA, PearceT@CarnegieMNH.org

The North American pupilloid land snails Gastrocopta pentodon (Say, 1822) and G. tappaniana (C.B. Adams, 1842) have similar looking shells and although G. pentodon tends to have a smaller, narrower, and less conical shell, in practice separating the two forms is difficult. While some workers cite habitat differences as evidence that the two forms are valid species (G. tappaniana occurring in moister habitats), an alternate hypothesis considers the possibility of one species whose shell morphology is influenced by the moistness of the environment. Vanatta & Pilsbry (1906, Nautilus 19: 121-128) illustrated 53 shells of the two forms but the differences between the forms are subtle. Discriminant function analysis of measurements from their illustrations gave a function that classified their shells 94% correctly. Applying this function to 577 shells from 129 localities throughout the Delmarva Peninsula, Eastern USA, revealed that both forms occur on Delmarva, with 74% of the specimens classified as G. pentodon. Moisture associations of plants at the sites address whether the two forms differ in the moistness of their habitats. Examination of specimens at sites where both forms co-occurred addresses whether they appear to be separate species or environmentally influenced forms of one species.

A Summary of the International Partulid Conservation Programme and its Significance for Other Group-level Managed Species
Paul Pearce-Kelly
Zoological Society of London, Regent's Park, London, NW1 4RY U.K.

The remarkable contribution that Partulid snail studies have made to the field of evolutionary genetics is well-documented. Likewise their tragic extinction crisis has provided a classic case-study of invasive predator-induced mass species loss. The resultant International Partulid Conservation Programme has provided the conservation community with a model for developing population management techniques and tools for species requiring management at the group (i.e. life-stage based) rather than at the individual level. This paper summarises the key elements of the Partulid management programme and discusses its wider significance for other group-level managed species.

A phylogenetic study of the invasive land snail species Praticolella griseola (Gastropoda: Polygyridae)
Kathryn E. Perez
Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, 35487, perez005@bama.ua.edu

Praticolellagriseola was described by Pfeiffer in 1841 from Veracruz, Mexico. This species is thought to live in Mexico and Central America with a disjunct population in South Texas, and invasive populations in the Southeastern US. Historical taxonomy in the genus Praticolella is primarily based on shell morphology. Molecular phylogenetic work on the genus Praticolella has revealed several distinctive lineages within Praticolella griseola. Molecular and morphometric data indicates that there are four species currently masquerading under the name “Praticolella griseola”. This includes three invasive species, one being true Praticolella griseola, and two other unnamed lineages which are invasive in the southeastern US, and one unnamed species native to South Texas.

Mollusk Survey and Basic Ecological Studies in Hells Canyon, Snake River, USA
David C. Richards1, C. Michael Falter2, Gary T. Lester3, Ralph Myers4
1EcoAnalysts Inc., Moscow, Idaho, 83843, ; 2Northwest Ecological Sciences, Moscow, Idaho, 83843; 3EcoAnalysts Inc., Moscow, Idaho 83843; 4Idaho Power Company, Boise, Idaho

We surveyed and conducted basic ecological studies of mollusks in a variety of habitats in reservoirs, tributaries, and the main stem of the Snake River, Hells Canyon. We focused our efforts on threatened and endangered species and species of concern by handpicking cobbles, visual shoreline searches, and SCUBA. Results include; absence of threatened and endangered species or species of concern in reservoir habitat; range expansion of a recently discovered new species of the hydrobiid, Taylorconcha sp.; dominance of two invasive species, Potamopyrgus antipodarum and Corbicula fluminea; extreme rarity or absence of native unionids in the main stem of the Snake River; and relative abundance of the limpet Fisherola nuttalli, a species of concern. We also related mollusk taxa abundance to environmental variables and to each other using several multivariate statistical methods. For example, Taylorconcha sp. abundance was directly related to P. antipodarum abundance, which suggests competition for shared habitats and Taylorconcha sp. was not found in the first 10 river miles downstream of Hells Canyon dam, which suggests unsuitable habitat in this section of the Snake River.

Discovery of Copulatory Structures in Male Helicinidae (Gastropoda: Neritopsina: Helicinidae)

Ira Richling
Zoological Institute, Christian-Albrechts-Universität zu Kiel, Olshausenstr. 40, 24098 Kiel, Germany, ira@richling.de

The Helicinidae represent a special family of terrestrial gastropods among only aquatic relatives having evolved independently from other terrestrial snails. Therefore, morphological features differ substantially, especially the reproductive system with separate sexes. Contrary to most related families and other terrestrial gastropods with inner fertilization, male helicinids were believed to lack special copulatory structures and the mode of sperm transfer remained doubtful.

Only recent investigations of Papua New Guinean species of the genus Palaeohelicina Wagner 1905 revealed such structures. While other Neritopsina process penes derived from the base of the right cephalic tentacle, in Helicinidae, they are developed as appendage of the inner mantle fold. Throughout the gastropods, a similar origin of copulatory structures is only found in the limnic Ampullariidae.

Morphological details will be given for Palaeohelicina and the presence or absence in other genera will be analyzed. Functional aspects within the whole family will be discussed in the light of these new findings and structural differenciations of the female reproductive system.

Report on the Current Status of Introduced Species of Achatinidae and Other Economically Snail and Slug Pests in the Eastern Caribbean

David G. Robinson1 and H. Angela Fields2
1 USDA APHIS PPQ / Academy of Natural Sciences, Philadelphia, PA 19103, USA, ; 2 Department of Biological & Chemical Sciences, University of the West Indies, Cave Hill, Barbados

The introduction of three species of the Achatinidae, Achatina fulica Bowdich 1822, Archachatina marginata (Swainson 1821) and Limicolaria aurora (Jay 1839) into the Eastern Caribbean is documented. The giant African snail, Achatina fulica, was deliberately introduced to Guadeloupe circa 1984. From Guadeloupe the snail was spread to Martinique by 1988, and to Saint Martin and Marie-Galante in 1995. Populations in both Guadeloupe and Martinique peaked in the 1990's and subsequently have fallen to relatively stable levels. Prior to 2000, A. fulica was introduced into Saint Lucia, and from there to Barbados in early 2000. On both these islands, populations of the species are increasing exponentially and spreading across the islands, despite the efforts of the local ministries of agriculture. Archachatina marginata was introduced from Benin to the Saint Joseph area in Martinique in 1987, but the species has not been found since; surveys in early 2005 did not detect its presence. Limicolaria aurora was introduced into Martinique in 1988, and is slowly extending its distribution through central Martinique, in some areas replacing populations of A. fulica. The current status and distribution of three pest veronicellid slugs, Veronicella sloanei (Cuvier 1817), Veronicella cubensis (Pfeiffer 1840) and Sarasinula plebeia (Fischer 1868) is also documented, together with that of three other pest snails, Zachrysia provisoria (Pfeiffer 1858), Bradybaena similaris (Rang 1831) and Amphibulima patula dominicensis Pilsbry 1899. Their potential impact on agriculture and the environment in the Eastern Caribbean is discussed.

Report on the spread of the Cuban slug Veronicella cubensis (Pfeiffer 1840) in Guam, and Rota in the Northern Mariana Islands, and the loss of molluscan biodiversity apparently resulting from introduced invasive gastropod species and the triclad flatworm Platydemus manokwari de Beauchamp 1963

David G. Robinson1 and Robert G. Hollingsworth2
1 USDA APHIS PPQ / Academy of Natural Sciences, Philadelphia, PA 19103, USA, ; 2 USDA ARS PWA, US Pacific Basin Agricultural Research Center, Hilo, HI, 96720, USA

As part of a study of snail and slug pests on subsistence and garden crops on islands in the American Pacific, the islands of Guam and Rota were surveyed for terrestrial gastropods in August 2004. Non-native, invasive species are by far the most pervasive elements of the malacofauna on both islands, with Veronicella cubensis reaching epidemic proportions on Rota. The Cuban slug is ubiquitous throughout synanthropic to relatively natural environments on both islands, and most of the agriculture and horticulture are being severely affected. Living specimens of native species as well as many other introduced snail species are now a rarity especially on Rota, their occurrence as documented by Bauman (1996) in the recent past indicated only by dead, eroded shells. Previously introduced snail species appear to have been decimated or even eradicated by more recent introductions, in particular Platydemus manokwari, and hope for the survival of native snail species in these islands appears remote.

Taxonomic Revision of Endemic Nicaraguan Freshwater Mussels (Bivalvia: Unionidae)

Kevin J. Roe1 and Adolfo Lopez de la Fuente2
1Delaware Museum of Natural History, Wilmington, DE 19810, USA, ; 2University of Central America, Managua,Nicaragua

Lake Managua and Lake Nicaragua are home to a group of endemic species of unionid mussels. As with many other unionids, these species were described in the middle part of the 19th century. These descriptions were based almost entirely on conchological characters that make assessment of the systematic relationships of theses species and their taxonomic placement relative to other unionids difficult to assess. These eight species have been placed into several different genera over the years e.g. Plagiola, Ptychoderma, Micronais, Arotonais, and unlike unionids from the United States and Canada have been largely ignored for the last century. Examination of existing museum holding of these taxa represents the first stage in the preparation of a monographic revision of the unionoid bivalves of the Central Nicaraguan lakes. Specimens, including type material were photographed and measured and evaluated with respect to published descriptions and synonymies. Based on the examination of existing specimens and descriptions the 11 nominal taxa endemic to the Nicaraguan lakes are placed in 6 species in two genera. Significant work remains to be done, including examination and description of gravid female specimens and their glochidia before a more complete picture of the number of species in the lakes and their affinities to other members of the Unionidae emerges.

Impacts of urbanization on the biodiversity of the imperiled snail fauna (Gastropoda: Prosobranchia: Pleuroceridae) of the Cahaba River, Alabama, USA

Lori Tolley-Jordan
Department of Biological Sciences, University of Alabama, Tuscaloosa AL 35210, USA

The conservation of the Pleuroceridae is of concern in the Mobile River Basin (MRB) since 31 of 38 extinct gastropod species from this drainage are pleurocerids. The fauna of the Cahaba River, as a global hot-spot for pleurocerid diversity, is of particular concern. Flows in the river are not regulated by dams, so gastropod diversity has not been affected by habitat alteration due to impoundment like other major MRB tributaries. Ongoing urbanization within its watershed, however, is expected to have consequences for its snail fauna. A 1993 survey documented 23 pleurocerid species among 109 sites in the drainage. Changes in land cover from 1992 to 2004 were quantified using GIS for 10 of these. Five sites showed a 13-36% increase in urban land-cover; five showed no change. Elimia cahawbensis, E. carinifera, E. carinocostata, E. clara and Pleurocera vestita occurred among these sites during 1993 (S = 0-4 spp./site) A comparison of species occurrence in 1992 and 2005 showed no change in S at 6 sites, while three lost 1 species, and one lost 3 species. However, reductions in S were not correlated with changes in land-cover. Factors not directly correlated with urban land-cover may thus be contributing to losses of snail diversity in the MRB.

Texas Seashells - A New Illustrated Guide

J.W. Tunnell, Jr., N.C. Barrera, R. Davenport, D. Hicks, and J. Andrews
Center for Coastal Studies, Harte Research Institute, Texas A&M University-Corpus Christi, Corpus Cristi, TX 78412, USA.

The last comprehensive work on Texas seashells was compiled by Jean Andrews over 30 years ago (1971, 1977). Her book Shells and Shores of Texas describes approximately 350 species of molluscs. In a collaborative effort, we are preparing an updated and expanded book on Texas seashells. Presently, the list of molluscs in the marine environments of Texas equals over 1400 species from the estuarine shoreline to the deep Gulf of Mexico. Because of the large number of species and inaccessibility of many of these molluscs, principally from older collections of offshore deep water habitats, accounts of molluscs with descriptions and photographs will be confined to habitats not exceeding 18 m (60 ft), but will also include Stetson Bank and the Flower Garden Banks. Approximately 750 species of molluscs are known from these habitats, and will be individually illustrated and described in the book. A complete checklist of all species including depth ranges and habitat will be included in the book along with a research history of conchology/malacology in Texas, biology and ecology of classes and families of molluscs, and favorite collecting habitats and localities.

Federal Efforts to Exclude Snails and Slugs Associated with Agricultural Imports

Frederick J. Zimmerman
United States Department of Agriculture, Animal and Plant Health Inspection Station, Plant Protection and Quarantine, Miami, Florida 33159 (305) 526-2825

At ports of entry in the United States some agricultural cargo, carriers, mail, and baggage are inspected to detect unwanted snails, slugs and other pests. Federal permit and phyto-sanitary inspection requirements further strive to allow entry only to pest-free, non-prohibited agricultural cargo. Even with the multi-faceted Federal inspection activities that are in place, the potential for new mollusk pest introductions will be ever present, and when combined with the invasive mollusk pests already present, America's native malacofaunas as well as the agricultural, hydrological, economic and other resources, remain at risk.

0 Comments:

Post a Comment

<< Home