Actinostola faeculenta ( McMurrich, 1893 )

Fautin, D. G., 2012, Taxonomy and distribution of sea anemones (Cnidaria: Actiniaria and Corallimorpharia) from deep water of the northeastern Pacific, Zootaxa 3375, pp. 1-80 : 22-24

Actinostola faeculenta ( McMurrich, 1893)

( Figures 15–17, Table 3, Appendix 7)

Synonyms

Cymbactis faeculenta: McMurrich (1893)

Paractinostola faeculenta: Carlgren (1949) persist in crevices between thickenings. In smaller specimens thickenings more or less circular, in larger ones thickenings toward distal end elongated and tapered, resembling drips of viscous fluid; those near margin of contracted individual may be digitiform. Oral and pedal discs concave; pedal disc may be leathery. Column varies from about 15 mm wide and long to more than 200 mm wide and 150 mm long. Three to five cycles of mesenteries at mid-column; to three cycles of mesenteries complete (third cycle complete only distally). Mesenteries of first two cycles sterile, those of third to fifth cycle may be fertile. Additional small, thin mesenteries at only extreme proximal end, so numerous could not be counted. Number of mesenteries inferred to be equal to number of tentacles, which may exceed 200. Oral disc and tentacles typically solid tan (color of ectoderm remaining in crevices of column). Marginal tentacles very short, tightly packed; discal tentacles longer, pointed, may have shallow longitudinal furrows, and dispersed over marginal half of oral disc. For detailed information on A. faeculenta , see McMurrich (1893) and Carlgren (1934b).

Cnidae. Gracile and robust spirocysts, basitrichs, microbasic p -mastigophores, and microbasic b - mastigophores. Sizes and distribution of cnidae given in Table 3; cnidae illustrated in Figure 16.

Distribution. Actinostola faeculenta was described from six specimens collected north of the Channel Islands, California, USA at 757 m ( McMurrich 1893). We examined additional specimens from southern California, north to British Columbia, and west to Japan from depths of 82 to 2,265 m ( Figure 17).

Taxonomic remarks. This is among the largest and most massive, as well as one of the most distinctive, sea anemones in the deep northeastern Pacific.

Specimens of A. faeculenta we examined agreed with both McMurrich (1893) and Carlgren (1934b). The large specimens have more than 200 tentacles. The type specimens have about 150, which is similar to the number in smaller specimens we examined; therefore, it appears that number of tentacles (and, by inference, mesenteries) increases with size.

Despite how conspicuous the species is, cnidae size and distribution in specimens of Actinostola faeculenta had not previously been reported so we report them here ( Table 3).

McMurrich (1893) could not find gametogenic tissue in the type specimens of Cymbactis faeculenta , so fertility pattern was not part of the generic definition. Although Carlgren (1934b) was also unable to detect gametogenic tissue in the type specimens, he moved the species from Cymbactis to Paractinostola ( Carlgren, 1928a) , a genus he had established ( Carlgren 1928a) for P. bulbosa ( Carlgren, 1928a) and P. capensis ( Carlgren, 1928a) , based on a more or less strongly lobed oral disc and fewer mesenteries at the base than tentacles. In his catalog to sea anemones of the world, Carlgren (1949) questionably also placed Cymbactis faeculenta in Paractinostola . Should the three species belong in a single genus, it would be termed Cymbactis , the older name

[no other species have been attributed to Paractinostola ; the combination Paractinostola ingolfi , found in Fautin and Barber (1999), is a lapsus for Parasicyonis ingolfi Carlgren, 1942 : Fautin 2011].

Riemann-Zürneck (1971) questioned the basis of differentiating Actinostola from Paractinostola . She subsequently ( Riemann-Zürneck 1978) placed P. bulbosa and P. capensis in Actinostola , finding the features Carlgren (1928a) used to define Paractinostola insufficient to distinguish it from Actinostola ; however, she did not mention P. faeculenta .

The key distinction between Cymbactis , as described by McMurrich (1893), and Actinostola , as described by Carlgren (1949), is the lobed margin of members of Cymbactis . Riemann-Zürneck (1978) noted that the margin of some specimens belonging to species of Actinostola can be lobed. Additionally, C. faeculenta , the type species of Cymbactis , has more tentacles than mesenteries at the base, a character not true for Actinostola according to Carlgren (1949). Häussermann (2005 [correction to Häussermann 2004]), who analyzed the variability of characters in Actinostola chilensis McMurrich, 1904 , found that some individuals of the species had more tentacles than mesenteries at the base and some had fewer. Thus these features do not distinguish Cymbactis from Actinostola . In examining fertile specimens of C. faeculenta , we found the first two cycles of mesenteries to be sterile; this state characterizes Actinostola . Therefore, Cymbactis conforms to the genus description of Actinostola , so Cymbactis is a junior synonym of Actinostola .

Material examined. See Appendix 7.