Guide to Climaconeis

Species of Climaconeis are marine and epiphytic (growing on plants) or epipelic (growing on fine sediment). One taxon was described from stromatolites.

Valves are narrow, linear or curved. The raphe is central, straight, or curved to one side at center in straight species, biarcuate in lunate species. Nearly half of the known species are curved. Although Climaconeis was named for the "ladder" of craticular bars on the valvocopula of the type species, only one other species is so far known to have such bars.

The plastid arrangement in longer species is distinctive as paired plates, not H-shaped chloroplasts, as previously thought (Lobban et al. 2010).

Although the copulae appear to be fairly uniform apart from the craticula when present on the valvocopula, some are more elaborate. Other details of copulae may prove useful as more species are discovered.

Species are distinguished on the basis of morphometry: shape (straight/curved), presence of craticular bars and/or stauros, number of plastid pairs, areola shape, and character of the external raphe branches.

Many new species have been added since Cox (1982) revised the genus with six species. Park et al. (2016) summarized the biogeography. Presently 21 species are recognized and the most recent key is in Lobban (2021). A question of whether the genus Okedenia might be reinstated for the curved taxa (Reid and Williams 2002, Prasad 2003) is still open and requires molecular data (Lobban 2018).