Further investigations on the sand-dwelling genus Cabra (Dinophyceae, Peridiniales) in South Brittany (northwestern Fran
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ORIGINAL PAPER
Further investigations on the sand-dwelling genus Cabra (Dinophyceae, Peridiniales) in South Brittany (northwestern France), including the description of C. aremorica sp. nov. Nicolas Chomérat & Alain Couté & Elisabeth Nézan
Received: 25 September 2009 / Revised: 15 January 2010 / Accepted: 16 February 2010 / Published online: 17 March 2010 # Senckenberg, Gesellschaft für Naturforschung and Springer 2010
Abstract Cabra is a genus of marine thecate sanddwelling dinoflagellates that is poorly known and of which only two species are described, C. matta and C. reticulata. In one fixed sample collected in 2007 in South Brittany, both of these species were recorded, together with a new third one. Cells of the three taxa were isolated and their morphology was characterized using scanning electron microscopy. New features previously unseen in C. matta were observed including the presence of a dense group of pores on the first antapical plate and the existence of pores of two different size classes on thecal plates. Cabra aremorica sp. nov. is 37–40 µm long and 31–38 µm deep and possesses a thecal pattern very similar to the other species described in the genus. However, C. aremorica differs from them by its overall ornamentation consisting in shallow alveolae, its polyhedral shape, and its very atypical apical pore complex. Observations of the third cingular plate c3 on the three Cabra species revealed the presence of a narrow extension that lays vertically and borders the ‘x’ (5″) plate on the ventral side of cells, which appears to be a constant feature in the genus. This fact not previously reported is crucial for the interpretation of the plate pattern and is very peculiar among dinoflagellates.
N. Chomérat (*) : E. Nézan Ifremer LER FBN, 13 rue de Kérose, 29187 Concarneau Cedex, France e-mail: [email protected] A. Couté Département R.D.D.M., Muséum National d’Histoire Naturelle, FRE 3206, USM 505, 57 rue Cuvier, case 39, 75005 Paris, France
Keywords Cabra . Dinoflagellates . Benthic . Biodiversity . Morphology . Taxonomy
Introduction Among sand-dwelling dinoflagellates, several genera have a very ‘unusual’ plate pattern and are monotypic, i.e. comprise only one species, the type of the genus. Among them, Cabra was introduced by Murray and Patterson (2004) with C. matta as the unique species, and stayed monotypic for several years. This very poorly known genus was only registered by Murray and Patterson (2004), Okolodkov et al. (2007) and Hoppenrath (pers. comm.). Recently Chomérat and Nézan (2009) described a new species, C. reticulata, from south of French Brittany. This new species is probably the same that Carlson (1984) observed several years before during a study of benthic dinoflagellates in the Caribbean Sea but although he identified it as a probable new genus, he did not provide any description. Morphologically, the genus Cabra is peculiar and characterized mainly by a polygonal shape in lateral view, a markedly ascending cingulum, and several prominent pointed flanges on the larg
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