Monthly Archives: April 2018

Type material in UK museums

Just announced: a new website which gives access to information (and images) of molluscan type material in the United Kingdom.

The announcement read: “The Mollusca staff of the Natural History Museum, London and the National Museum of Wales, Cardiff have been working to digitally unite the type specimens found in Mollusca collections across Great Britain into one comprehensive database.

Thanks to the John Ellerman Foundation’s Regional Museums and Galleries Fund the first phase of our project has now been released, bringing together the type collections of seven partner Museums (Manchester, Liverpool, Leeds, Glasgow Hunterian, Glasgow Kelvingrove, Exeter and Newcastle).

The curatorial staff from the leading institutions have been able to help research, catalogue and photograph c. 600 primary types to unite them as never before. Our online database also gives examples of handwriting to help identify type material as well as information and resources to assist in tracing historical mollusc collections including an updated Appendix IV from S.P. Dance’s ‘A History of Shell Collecting’ (1986) reproduced with kind permission of the author.

In the near future we will be adding further secondary type specimens from our phase 1 project partners as well as primary type material from the National Museum of Wales. In the longer term we will be adding more UK based type collections as further funding becomes available.”

The database presents excellent photographs and various ways to search for specimens. It is an important source for anyone looking for type material from historical collections, especially if the collector resided in the UK or the collection is known to be in museums there. However, as the illustration above shows, also unexpected finds are possible.

Snail pheromones

Not a study with Neotropical species, but still of interest as there are several groups of snails (e.g., Orthalicidae, Bulimulidae) which are comparable to the ones used in the study by Holland et al.: Hawaiian tree snails and the use of pheromones in detecting trail following.

“The importance of pheromones in insect and mammal social systems is well docu- mented, but few studies have addressed the role of pheromones in land snail behavior. In this investigation, we used a series of behavioral trials and direct analysis in real time mass spectrometry (MS) to test the hypothesis that land snails use mucous trails in orientation and chemical communication. We worked with six endemic Hawaiian land snail species in four genera, three subfamilies, and two families. We tested conspecific trail following in five of these species, and trail following occurred at a statistically significant frequency for each of the species tested (n=181, p-values ranged <0.0001–0.0494). Percentage of conspecific trials that showed trail following ranged 66.7–94.1%. None of the interspecific tests revealed evidence of trail following among species (n=105, with p-values of 0.0577–0.5000). Juvenile achatinelline snails did not follow trails of conspecific juveniles (n=30, p=0.5722) or adults (n=30, p=0.4278), nor did adults follow juvenile trails (n=30, p=0.5722). Comparative MS analysis of adult and juvenile trails showed distinct chemical signatures in the two groups. Signals corresponding to medium- and long-chain fatty acids and other unidentified small molecules were present in adult but not in juvenile trails. Considered together, these results support the hypotheses that trail following could serve an important social and reproductive function. This discovery provides evidence for the presence of an ephemeral tree snail pheromone, which could have important implications for the conservation of these increasingly rare and threatened species.”

This interesting study is clearly only possible thanks to the availability of a well-equipped laboratory, and a snail breeding programme allowing multiple specimens to be  at hand for the trials. The difference in pheromones between juveniles and adults, and between species, may prove a useful starting point for further research on the occurrence of this phenomenon in other snail families.

Holland, B.S., Gousy-Leblanc, M, & Yew, J.Y., 2018. Strangers in the dark: behavioral and biochemical evidence for trail pheromones in Hawaiian tree snails. – Invertebrate Biology (Advance online access). DOI: 10.1111/ivb.12211

Ovachlamys fulgens redescribed

Salles et al. just published a paper on the tropical Helicarionid snail Ovachlamys fulgens (Gude, 1900) for which they used Brazilian material to redescribe the species.

Schermafbeelding 2018-04-10 om 11.49.50

Their abstract reads “The geographical distribution of the jumping snail Ovachlamys fulgens Gude, 1900, originally described from Loo-Choo Island, is expanding rapidly throughout the tropics. The full extent of the environmental damage caused by the in- troduction of this exotic species is still unknown. So far, it has been implicated in damage to orchids and horticultural plants. Ovachlamys fulgens is only known by a few characteristics of the shell and information on its anatomy is scant. The present study aims to redescribe this species based on specimens from Brazil, which is here characterized by the a globose shell, with wide aperture, externally micro-sculptured with undulating spiral groves, umbilicus partially obliterated by a thin plate, pedal sole tripartite, cephalopedal mass consisting of a series of oblique muscles, mantle with two flattened lobes, large caudal horn, pallial cavity small, vascular system evident, auricle fibrous, ventricle highly muscular, aorta subdivided in cephalic and gastric veins, a large kidney internally folded, jaw smooth and crescentic, radulae with 127 teeth per row (55-(8)- 1-(8)-55), each row with about 25 mm, crop absent, salivary glands fused, stomach large with thin walls, ovotestis with at least three distinct lobes, talon totally immersed in the albumen gland, uterus with two regions, capsule gland hardly visible, bursa copulatrix small and sacculiform, penial sheath present, epiphallus small and narrow, nervous ring asymmetrical, visceral ganglion on left side only, five and six nerves running from each cerebral and pedal ganglia, respectively, one statocyst immersed in each pedal ganglion, and two pairs of ganglia (mandibular and buccopharyngeal ganglia) extra to the nervous ring.”

Schermafbeelding 2018-04-10 om 11.50.30

The authors have done a thorough morphological and anatomical study, which will undoubtedly help to identify this species in future.

Salles, A.C.A., Oliveira, C.D.C. & Absalão, R.S., 2018. Redescription of the jumping snail Ovachlamys fulgens (Gude, 1900) (Gastropoda: Helicarionoidea: Helicarionidae): An anatomical and conchological approach. – The Nautilus, 132 (1): 19-29.

Bulimulus as host for nematods

Today I was alerted of a citation of my paper on Bulimulus phylogeny, and when I looked up the citation I found a paper by Martins et al. which will appear in the Journal of Invertebrate Pathology.

“The terrestrial gastropod Bulimulus tenuissimus is widespread in South America. It is an intermediate host of many parasites, but there are no records of infection of this snail by Angiostrongylus cantonensis, despite the occurrence of this parasite and angiostrongyliasis cases in the same areas in which B. tenuissimus occurs. For this reason, it is important investigate the susceptibility of B. tenuissimus to A. cantonensis-infection, since it can be used as intermediate host of A. cantonensis, increasing the list of terrestrial gastropods that infect wild and domestic animals and humans with this parasite. The purpose of this study was to evaluate the susceptibility of B. tenuissimus to experimental infection with L1 larvae of A. cantonensis. The snails were exposed to 1,200 L1 larvae and it was possible observe many developing larvae in the cephalopedal mass and mantle tissues, with intense hemocyte infiltration and collagen deposition, but no typical granuloma structures were formed. The glucose content and lactate dehydrogenase activity in the hemolymph varied, indicating an increase of anaerobic energy metabolism in the middle of infection, but with a tendency to return to normal values at the end of pre-patent period. This was corroborated by the marked reduction in the glycogen content in the cephalopedal mass and digestive gland in the first and second week after exposure, followed by a slight increase in the third week. The content of pyruvic acid in the hemolymph was 14.84% lower at the end of pre-patent period, and oxalic acid content was 41.14% higher. These results indicate an aerobic to anaerobic transition process. The PAS reaction showed a large amount of glycogen inside the developing larvae and muscular tissues of the cephalopedal mass, indicating that despite the high consumption of this polysaccharide by the parasite, the snail is able to maintain its energy metabolism based on carbohydrates. The results reveal that B. tenuissimus is a robust host, which can live with the developing larvae of A. cantonensisand overcome the metabolic damages resulting from parasitism.”

No phylogenetic related work thus, it seems that the citation was only used to support the wide-spread occurrence of Bulimulus species in different areas and the fact that some of these are easily imported and may act as alien species. I also found a (unjustified) citation in Martins et al. of a paper by Parent & Crispi dealing with the radiation of Galápagos Naesiotus species, which were misidentified as Bulimulus.

Although this seems a case of serendipity, it is interesting to know that Bulimulus tenuissimus is a potential host for Angiostrongylus cantonensis, given the fact that this is a potential health threat for humans. An update will be given once this paper is formally published.

Martins, F.G. et al., 2018. Bulimulus tenuissimus (Mollusca) as a new potential host of Angiostrogylus cantonensis (Nematoda), a histological and metabolic study. – Journal of Invertebrate Pathology