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The
taxonomy of the western Atlantic Oliva species has challenged
experts for many years. There are three quite distinct morphospecies
involved: O. sayana Ravenel, 1834, O. scripta Lamarck, 1811,
and O. fulgurator (Röding, 1798). Although the colors and patterns
are extremely similar in some instances, the three taxa can be separated
by a number of features - albeit ones which are relatively subtle compared
to the differences among the extensive group of Indo-west Pacific
congeners. One of the most durable and simple of these distinctions is
the formation of the suture. In O. sayana, there is a moderately
deep suture bordered by a suprasutural spiral ridge. The sutural channel
of O. scripta is extremely broad, and is especially conspicuous at
its apertural end. O. fulgurator has a narrow to moderate sutural
channel without the ridge. These features are shown on the
images below. Recently, the taxonomy of Oliva fulgurator has been painstakingly analyzed by Tursch, Greifeneder, and Huart (1998), who concluded that this nominal taxon was the earliest name for a group of named forms belonging to only one species. As a consequence, some 41 species-level taxa were placed in synonymy with Röding's species. These synonyms include names published from 1811 to 1990 in 19 works by nine authors. Among them are the likes of O. reticularis Lamarck, 1811, O. graphica Marrat, 1871, and O. bifasciata Küster in Weinkauff, 1878, whose names appear extensively in the literature and properly apply to shells which appear to represent distinct taxa. Nonetheless the shape (by a substantial number of metrics) as well as shell pigmentation and pattern of the types of the synonymized taxa plus nearly 800 shells collected from 48 localities from Bermuda to southern Brazil seem to vary in such a way to indicate pockets of genetic isolation in many instances, yet, when an inclusive perspective is applied, formed a continuum. Some of these named taxa are illustrated here and regarded as "forms" without formal taxonomic standing. (H. G. Lee) 
Tursch, B., D. Greifeneder, and D. Huart, 1998. A puzzle of highly multiform species: Oliva fulgurator (Röding, 1798) and related American taxa. Apex 13(1-2): 1-61, April 20. |
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[Click on the individual species names to view more images.] |
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