Coscinodiscus y Coscinodiscopsis (Bacillariophyceae) del Parque Nacional Sistema Arrecifal Veracruzano, golfo de México

Coscinodiscus Ehrenberg, 1839 is one of the most common genus of centric diatoms. Species identification is based on dimension and characteristic of the frustule: arrangement and density of areolae, position of macrorimoportulae and the occurrence of microrimoportulae over the valve besides of the marginal ring. To observe all these characters is necessary to carry out detail studies of the valves by cleaning of frustules. In the National Park Sistema Arrecifal Veracruzano (NPSAV), there are 5 species recorded. The aim of this work was to study the species diversity of Coscinodiscus hypothesizing a detailed observation of frustules would raise the diversity. Using photonic microscopy, we studied phytoplankton samples belonging to one-year monthly-collected samples in the polygon of NPSAV. Eight species of the genus were identified: Coscinodiscus asteromphalus Ehrenberg, 1844, C. centralis Ehrenberg, 1844, C. concinnus Smith, 1856, C. gigas Ehrenberg, 1841, C. granii Gough, 1905, C. perforatus Ehrenberg, 1844, C. radiatus Ehrenberg, 1840, and C. wailesii Gran et Angst, 1931. Additionally, we identified other related species recently transferred from the genus: Coscinodiscopsis jonesiana (Greville) Sar et Sunesen, 2008. The species richness of Coscinodiscus in NPSAV is medium compared to other regions of Mexican seas.