Note: This family as conceived by Komárek & Anagnostidis (1986: 216) comprises nonfilamentous forms with facultative nanocyte production. It corresponds to the Chroococcidiaceae of Geitler (1933: 623) in the sense of Bourrelly (1970: 333) with the addition of Xenococcus, which Bourrelly included in the Hyellaceae (a later synonym of Hydrococcaceae). The assignment of Xenococcus to one or the other of the two families depends upon whether pseudofilaments are ascribed to the genus, with Bourrelly admitting that it is often difficult or impossible to distinguish filaments in the pseudoparenchymatous thallus. Komárek & Anagnostidis adopted the family name Xenococcaceae Ercegovic (1932: 138, 141), anticipating the legal rejection of the generic name Dermocarpa (an earlier synonym of Xenococcus) together with the family name Dermocarpaceae Geitler (1925b: 247). At the present time, however, Dermocarpaceae is the correct name for this family.
Note: When Xenococcus Thuret was proposed (in Bornet & Thuret, 1880: 74), it was distinguished from Dermocarpa P. Crouan & H. Crouan (1858: 70) by its lack of endospores (nanocytes). After observing endospores in X. schousboei Thuret, the type species of the generic name, Batters (1890: 231) communicated this information to Bornet, who pointed out that Xenococcus must be considered a synonym of Dermocarpa. At nearly the same time, Hansgirg (1893: 234) came to the same conclusion based on observations of endospores in X. kerneri. Subsequent workers, however, usually recognized both genera, applying the name Dermocarpa to unicellular forms (assigned to the Chamaesiphonales or the segregate order Dermocarpales) while applying the name Xenococcus to forms with a pseudoparenchymatous disc from which short filaments may arise (assigned to the Pleurocapsales). This treatment was upset when J. Feldmann & G. Feldmann (1953) showed that there are vegetative cell divisions in the type species, D. violacea P. Crouan & H. Crouan, which thus becomes indistinguishable from Xenococcus. The correction of the application of the name Dermocarpa has been perceived by several authors (e.g., Komárek & Anagnostidis, 1986: 200, 203) as a source of confusion which could be obviated by expunging the name from algal nomenclature through legal mechanisms (conservation and rejection) provided by the ICBN. No formal proposals have been submitted, however, and we therefore follow Bourrelly in adopting the name Dermocarpa in preference to Xenococcus.
Xenococcus acervatus Setchell & Gardner in Gardner, 1918b: 459–461, pl. 39: fig. 13 (type locality: San Francisco Bay, California, U.S.A.).—Børgesen, 1936: 59.— Frémy, 1939: 55.— Newton, 1955b: 143.— Desikachary, 1959: 182, pl. 31: fig. 28.— S. Dixit, 1968: 11.— Nizamuddin & Gessner, 1970: 7.— S. Dixit, 1980: 59.— Lambert, Steinke, & Naidoo, 1989: 483, fig. 7, tables 2, 3.— G. Subramanian et al., 1989: 311, 316, 318.— Steinke & Naidoo, 1990: table 1.— S. Silva, 1991: 146, 149, fig. 2.13, tables 1–3.— Shameel & J. Tanaka, 1992: 5.— Thajuddin & G. Subramanian, 1992a: table III.
Dermocarpa acervata (Setchell & Gardner) Pham-Hoàng Hô, 1969: 18.
INDIAN OCEAN DISTRIBUTION: Bahrain, India, Mozambique, Pakistan, South Africa, Sri Lanka.
Note: Drouet & Daily (1956: 112, 116), after examining the holotype of this species (in UC), assigned it to Entophysalis conferta (Kützing) Drouet & Daily.