Sea anemones (Actiniaria
and Corallimorpharia) of 25-30 species live intertidally along the coast
of North America; most range into subtidal waters. Anemones of almost as
many species occur only subtidally, some at abyssal depths. Knowledge of
deepwater species had been primarily taxonomic, based on occasional trawled
specimens. In the past few decades, many specimens of deepwater anemones
have been trawled from numerous sites along the coast, and from some sites
repeatedly, permitting research on distribution and biology of the animals.
As with some other deepwater marine organisms, the depth of occurence of
several anemone species diminishes with latitude. One abyssal species of
which specimens were collected for many years at one site reproduces seasonally.
It occurs almost exclusively on manganese nodules; another occurs
only on shells of living scaphopods. Photographic and video still and moving
images are increasingly being recorded, and specimens are even being collected
alive, permitting knowledge of live appearence and activity. The Venus
fly-trap posture is widespread among anemones of a variety of taxa; it
may be important in feeding on the rain of particulate matter that is presumably
the animals' primary source of energy. Actinians are among the most diverse
and abundant taxa in the deep northeast Pacific.
Very few taxonomic studies
in the order Actiniaria have employed nucleotide sequence data on an intrageneric
level. Our goal is to establish whether two putative new species of sea
anemones in the genus Urticina from the North American Pacific Coast
are new species or are local variants of described species. In order to
do this we are using nucleotide sequence data as well as a morphological
character that has been used traditionally in anemone taxonomy: types,
size, and distribution of cnidae. We have sequenced a region of the mitochondrial
cytochrome c oxidase subunit I gene (COI) as well as regions of the two
nuclear internal transcribed spacers (ITS1 and ITS2) of the two putative
species and the two described species that they most closely resemble externally.
We will compare the levels of inter- and intraspecific variation among
the two sets of sequence data.
Preliminary data reveal that the COI gene is highly conserved and unsuitable for a taxonomic study on the species level in this genus. According to the analysis of the cnidae, one of the putative new species is different from the one described species that it resembles externally, whereas the other putative new species is not. Results from the molecular and the morphological analysis will be compared.
Sea anemones in the genus Urticina are common in shallow waters of the North Pacific and North Atlantic. I examined living and preserved specimens of the five currently recognized and one putative new species on the west coast of North America. Individuals of each species can be identified in life by color, pattern, and habitat. Museum specimens can be identified by cnidae and column specializations. Urticina crassicornis has a solid red, solid yelow, or mottled red and green column, and basitrichs reaching 95 µm in the actinopharynx. Urticina coriacea has basitrichs reaching 65 µm in the actinopharynx, and adheres debris to the dark red column. Urticina lofotensis has a bright red column with verrucae, and holotrichs in the tentacle tips. Urticina columbiana has thick, crusty verrucae on the orange-red column. Urticina piscivora has either white or pink tentacles, and microbasic p-mastigophores in the smooth, dark red column. The putative new species has a bright red column with white verrucae and adheres debris; the northern limit of its range is much further south than that of any other species in the genus. Preliminary data suggest that color of the marginal sphincter muscle may be a useful character in freshly-killed and alcohol-preserved specimens. Specimens of the North Pacific species will be compared with those of North Atlantic species as part of the taxonomic revision of the genus funded by the NSF PEET program (grant # DEB95-21819).
Copyright © 1997 by the Society for Integrative and Comparative Biology.