Marine Shells of the Seychelles

Submitted by Steve Wilkinson on Sun, 09/05/2010 23:53

Alan G. Jarrett. 2000. Carole Green Publishing (2 Station Road, Swavesey Cambridge, CP4 5QJ) 149 pp. ISBN 1-903479-00-2.

Review source

Originally reviewed by Kevin Brown in 2001.

Published in Journal of Conchology (2001), Vol.37

Alan Jarrett spent ten years working as a teacher in the Seychelles; he took full advantage of the opportunity this provided to both collect and study local marine mollusca, thus this book is the culmination of extensive first-hand field work.

This identification guide gives detailed descriptions of some 649 species from the Seychelles, 535 gastropods and 114 bivalves. The species are arranged in standard taxonomic order, and alphabetically within each genus making the book very easy to use. Each species is clearly described and each description is complimented with a good quality colour photograph; these generally show both dorsal and ventral views of gastropods and both interior and exterior views of bivalves. The specimens illustrated all come from the Seychelles, where necessary using museum specimens to supplement those collected by the author. For completeness some 20 additional species reported from earlier literature are also mentioned in the text although without detailed descriptions or illustrations. It is particularly pleasing that a number of smaller species, often overlooked in popular works, are here given good coverage - species of Engina, Rissoina, Truncatella, Fenella, Pyrene and no less than 11 Triphorids. It is, however, surprising that nowhere in the descriptions of the Triphorids is it mentioned that these shells are sinistral; the illustrations clearly show this, but illustrations are often inadvertantly reversed; indeed elsewhere in this book both Ovula ovum and Monilea vernicosa are shown erroneously as apparently sinistral species.

Introductory sections of the book cover methods of collecting, cleaning shells, keeping molluscs alive in an aquarium, and the importance of recording data, and the book also contains a glossary, bibliography and index. One theme emphasised in the section on methods of collecting is that of responsible collecting with collectors urged to limit their 'take' to one or two specimens of any species, to avoid damaging living coral, to replace any disturbed stones or dead coral in their original positions etc. This theme recurs else- where in the book with the author commenting "When the female (Cowrie) is found protecting her egg capsule clusters she should not be collected, no matter how fine the specimen or how rare the species" and it is obvious that Alan Jarrett practices what he preaches for Rapa rapa is illustrated with beach collected specimens and the comment "Since this species lives imbedded in soft coral I have only collected washed specimens". We are also reminded that conservation regulations are in force in the Seychelles which must be observed by collectors.

One of the strengths of this book is the inclusion of much detailed observations of both the habits and habitats of many of the species covered. To give a few examples; the author observes of Malea pomum "I have collected mature specimens of this species ranging in length from 32-90 mm. The larger specimens were collected from deeper water." and that Epitonium margarita "Can be collected from sand beneath the solitary coral Fungia which is found resting on sand and appears to have some sort of association with this coral". Maculotriton serriale "is moderately common in shallow water, where it lives in coral debris on coarse sand... all colour forms seem to coexist in the same habitat". Tonna dolium is "Most easily collected at daybreak in depths of ten metres or more near Thallasia growing on a sandy sea bed. The animals are found buried with part of their shell projecting from the sand" while Bursa cruentata is found "Inhabiting holes in hard intertidal flats, particularly where the sea is inclined to be rough".

Descriptions of the cowrie shells are deliberately brief since "The group has been covered well in several major books"; instead the author provides detailed descriptions of the animals' appearance from his own observations. It is unfortunate that these descriptions of the living molluscs do not extend to other groups, we are for example tantalisingly told that Haminoea simillima 'Is uncommon but when found is usually one of a dozen or more that will be found nearby. They inhabit rock pools, moving through matted algal fronds. The animal is very beautiful but after it's removal leaves a thin white translucent shell", we are left wondering in what way the animal is beautiful.

There is some taxonomic confusion in a couple of places; Pusia is treated as both a full genus and as a subgenus of Vexillum while Tellina is treated as both full genus and as a subgenus of not only Pharoanella but also Quadrans and Quidnapagus (sic), whereas Pharoanella, Quadrans and Quidnipagus are all treated by Vaught as subgenera of Tellina. A small number of misidentifications have crept in, on p.48 Cymatium hepaticum appears to be the closely related Cymatium closeli Leu, 1987, on p.54 Chicoreus maurus is Chicoreus saulii (Sowerby, 1834) while on p.84/85 the species shown as Marginella lilacina is Closia sarda (Kiener, 1834). Judging from the Bibliography these few misidentifications proba- bly stem from a lack of access to recent monographs, which may also explain the use of a number of old or invalid names, for example Chicoreus palmarosae (Lamarck) is generally in use today rather than C. rosarius (Perry) which is here treated as the valid name for the species.

There are one or two areas where this book could have benefited from some added editorial input, for example in the general bibliography where I would have expected to find the dates of publication for the works cited and where it would have been clearer had the authorship of publications been consistently given in the same format rather than intermixing Hinton Alan and Kensley Brian with Barry Wilson and Gary Rosenberg. In these examples it may be easy to distinguish the surname from the Christian name, however, anyone who is not a native English speaker could have unneces- sary problems, and without prior knowledge Kira Tetsuaki could be taken either way - Kira is the surname in this case. It is particularly regrettable that only one of the three principle references, detailing previous writings specifically on Seychelles mollusca, should have sufficient bibliographical information to be easily traced.

Despite any minor failings of taxonomy - which is prone to change anyway, and misidentifications - which can be easily corrected, this book is a fine example of the contribution which an amateur collector can make to conchology, through long term collecting, careful observation and recording and most importantly through publishing, whether in a full scale book like this or in smaller scale articles. There are many areas of the world where we could benefit greatly from similar studies, and anyone with similar opportunities should be encouraged to follow Alan Jarrett's lead and could do no better than to read this book as a good example of what can be achieved, 'Marine Shells of the Seychelles' will not only be useful as the first comprehensive modem book on the marine molluscs of the Seychelles but through it's detailed recordings of habitats will be beneficial to conchologists over a much wider area.