Tag Archives: literature

Book review: Cossignani 2018 South American landshells

Cossignani, T., 2018. South American Landshells: 1-240. L’informatore Piceno, Ancona. ISBN 978 888 6070 35 5. Price € 120,00 net.

South America is a large continent, with thousands of land snails. Several books covering specific countries and aimed at a more general readership and checklists for some other countries do already exist (Ramirez et al., 2003; Simone, 2006; Massemin et al., 2009; Linares & Vera, 2012). Therefore the publication of Cossignani’s book seems a useful addition to the literature as no one has ventured before to cover the land snails of this continent as a whole.

The author’s foreword of this atlas, together with 2300 colour photos makes clear that these pictures are, for the greater part, from the collection in the Museo Malacologico Piceno, with additional photos from friends, collectors, traders and museums. The author states to have no claims to present scientific reviews or validation of any kind, and the work is essentially aimed at land shell collectors, although several freshwater snails and mussels are also included. The book is alphabetically ordered by country (all except Guyane, Suriname and French Guiana), and for each country species are arranged alphabetically according to genus. For each species the following data are presented: the author and year, place of origin of the specimen photographed, measurement in mm, and museum depository in case of type material. A brief bibliography and an index to species names complete the book.

Despite the author’s assertion that he “deliberately neglected those malacological areas for which there are recent and valid publications, Brazil in particular”, pages 58-114 are dedicated to this country. This is a serious duplication of Simone’s book, which offers the same information but in a better taxonomical way. In Cossignani’s book the reader is at loss to which family a species belongs, and related genera are not grouped together as the alphabetical order does not allow this. The photos are of good quality and generally show at least two different views. Often the same species is represented by several sets of photos. Although this may be useful for species with a variable morphology (e.g., colour pattern), the degree of redundancy is disturbing when several sets of similar shells are presented. 

The value of a book like this depends undoubtedly on a correct nomenclature. And although this does not necessarily mean that the latest scientific insights have to be reflected, a consistent and rather up to date taxonomy would be necessary. For some groups this seems to be correct but for others there is much doubt. I do not pretend to have knowledge of all families of South American land snails. But for those belonging to the Orthalicoidea I spotted several grave errors. E.g., on page 120 Bothriembryon reflexus is mentioned for the Chilean fauna; however, this species does not belong to this Australian genus but to Plectostylus which is treated on page 123-126. Some species are mentioned with different genera (azulensis on page 13 with Bostryx, on page 20 with Discoleus; only the latter is correct). Several species are associated with the wrong fauna (to mention only the most striking ones: Bostryx nigropileatus does not occur in Argentina but in Peru; Porphyrobaphe iostoma not in Chile but in Ecuador). Some species have outdated nomenclature (e.g., page 53 Helix culminea and Helix hygrohylaea) or are assigned to a wrong genus (e.g., Bulimulus catlowae [sic, catlowiae] from Ecuador is in fact Naesiotus quitensis). Placostylus malleatus is mentioned for the Colombian fauna, but is in fact a species from the Fijian islands. Also several typos were found in species names. Some years ago Cossignani published a similar book on African snails, for which I heard very mixed stories especially about the quality of the nomenclature. I am afraid that the author has made similar mistakes this time.

After several countries a checklist is given of all or part of the families. These lists appear partly copied from the internet, some are given without source; almost all are undated. The credibility of these lists is thus disputable. And it may be clear: the author has only treated part of the land snail fauna (e.g., 8% of the Colombian and 25% of the Peruvian terrestrial species). The title of the book remains far too ambitious! 

Despite the mentioning of museum abbreviations with photos taken from their websites (and sometimes not mentioning these abbreviation), I spotted several photos which seem to have been taken from the literature without giving credit to the original authors. The statement in the colophon that all photographs, except mentioned otherwise, have been taken by the author thus cannot be true.

This book could have filled a real gap if it would have been set up in a systematic way. And if more effort had been given to illustrate available type material (with proper credits). Now it is a garbage can full of misidentifications, wrong assignments, redundant pictures and lists of doubtful usage. But my main concern is that this book leads the target group of “land-shells collectors” too often in the wrong way. The overall impression of this book is unfortunately too bad and I cannot recommend Cossignani’s work, despite the fact that it has some useful elements.

References

Linares, E.L. & Vera, M.L., 2012. Catálogo de los moluscos continentales de Colombia. Bogotá (Instituto de Ciencias Naturales): 1-360.
Massemin, D., Lamy, D., Pointier, J.-P. & Gargominy, O., 2009. Coquillages et escargots de Guyane / Seashells and snails from French Guiana. Mèze (Biotope) / Paris (Muséum nationale d’Histoire naturelle): 1-456.
Ramirez, R., Paredes, P. & Arenas, J., 2003. Moluscos del Perú. – Revista de Biología Tropical, 51 (Supplemento 3): 225-284.
Simone, L.R.L., 2006. Land and freshwater molluscs of Brazil. São Paulo (EGB, Fapesp): 1-390.

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Ruminia decollata in Cordoba

Reyna & Gordillo just published a brief research note in which they report the finding of specimens of Ruminia decollata (Linnaeus, 1758) in Córdoba Province, Argentina.

According to these authors this snail is a potential host of roundworms that are common in dogs and cats, and thus may also affect susceptible humans. Moreover, this alien species may affect crops and horticultural products.

Reference:
Reyna, P. & Gordillo, S., 2018. First report of the non-native snail Rumina decollata (Linnaeus, 1758) (Subulinidae: Gastropoda) in Córdoba (Argentina): implications for biodiversity and human health. – American Malacological Bulletin, 36 (1): 150-152.

Newly introduced snail

Agudo-Padrón is a frequent author of news about the southern Brazilian malacofauna. This time he published about a new introduction of a species from Asia, which he identified as Macrochlamys cf. indica (Benson, 1832).

This record was published in a new online journal from the University of El Salvador, named ‘Minerva’; a name which is already applied by at least 2 other journals and thus may be considered as a junior homonym 🙂

Reference:
Agudo-Padrón, I & Souza da Luz, J., 2018 (‘2017’). Primer record confirmado de ocurrencia de un Caracol terrestre indo-asiático en Brasil y las Américas. – Revista Minerva, El Salvador, 1: 19-27.

New Urocoptid from Hispaniola

Just released: a paper by Thomas Watters dealing with the urocoptid genus Gyraxis, and describing a new species. The abstract reads “The genus Gyraxis in Hispaniola is reviewed, currently only known from the area of the Bahía de Samaná in the Dominican Republic. It includes three taxa: Gyraxis samana (Clench, 1966), G. sericata (Pilsbry, 1903) and G. excalibur new species. The radular morphology and isolation from Cuban Gyraxis suggest they may yet require a new genus”.

Watters also, when dealing with the nomen inquirendum Cylindrella gouldiana Pfeiffer, 1853, indicated this taxon has never been figured and that Crosse subsequently mentioned the first precise locality for the species (“Région Dominicaine: rochers du Tablaso, près San Cristobal (A. Sallé)”). Watters expressed “it is not clear how he knew this”. This answer is simple: Crosse always indicated behind his localities the collector of the material, in this case Sallé. The material which Crosse saw may either have been returned to Sallé or have ended up in the Crosse collection. Both collections have been dispersed after their owner’s death, and the current depository of the material is unknown.

Reference:
Watters, G.T., 2018. The genus Gyraxis Pilsbry, 1903 (Gastropoda: Urocoptidae) from Bahía de Samaná area of the Dominican Republic. – Journal of Conchology, 43: 103-108.

 

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.

Reference:
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.

Reference:
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.

Reference:
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