Species list


The following discussion deals with the conventions of labeling, organization and methods that we follow throughout the site.



The purpose of this site is to present the observations of the authors and other Hawaiian researchers who have contributed to it. Therefore, we don't include comprehensive discussions of the species or, necessarily, restate reports of their behavior/characteristics from elsewhere in the Pacific. For that, we refer the reader to Bill Rudman's Sea Slug Forum and other sites. Furthermore, conclusions and interpretations on this site are based primarily on our own observations and do not necessarily reflect the observations or opinions of other researchers (unless otherwise noted).

Although we may suggest that some species might be synonyms, we do not intend to make nomenclatural changes on this site. In cases where the assignment of a genus is uncertain we place a "?" in parenthesis after it.

Nomenclature is based on the recommendations and preferences of Dr. Terry Gosliner with the exception of a few instances where we have "agreed to disagree" on matters of splitting or lumping. Final choices (and any errors) in such cases are our responsibility.

The purpose of the thumbnail section is to provide a "cascading gallery" for quick identification. The introductory material for each taxon has been deliberately kept to a minimum so readers won't have to scroll down too far to get to the thumbnails. For further discussion, we direct the readers to other sites that deal with such subjects in greater detail. All thumbnails are smaller versions of photos appearing elsewhere on the site and photographers are credited under the primary photos. Each taxon is also linked to a comprehensive species list for those who wish to go directly to the descriptions. Finally, we provide a single page containing all the thumbnails without introductory material for those who find that format convenient.

In those few cases where we do not have a photo taken in Hawaii of a species that, nevertheless, is known to be present we may include a photo taken elsewhere as an aid to identification. These photos are identified by the abbreviation "(PNH)" after the name bellow the thumbnail and by the phrase "(Photo not from Hawaii)" below the photo on the species page. If a species is mentioned in the family introduction as "possibly Hawaiian but not confirmed" a link is provided to photos of the species on another site.

When we've changed the genus of unidentified or undescribed species that are listed by number, the numbers usually haven't been altered (except to resolve conflicts) in order to minimize relabeling. So, they may not reflect the number of species in their present genus. For example, use of "Cuthona sp. #17" doesn't necessarily mean that there are 17 unidentified Cuthona spp. on the current list.

Many animals were photographed on an artificial sand background. Therefore, such photos should not be interpreted as implying that they are sand-dwellers. Artificial rock backgrounds were also used for many "dish" shots.

Our intent is to portray the animals, themselves, in a manner that is as close to reality as possible. In many cases, we've used Photoshop to mitigate "photographer errors" (poor exposure, poor white balance, confusing back-scatter, etc.). But, the purpose of such editing has always been to restore the image, as closely as possible, to the original appearance of the animal, not to alter it.

Species pages:

The maximum size is the greatest body length of Hawaiian animals that we are aware of either from our own observations or the literature (we do not routinely include data from elsewhere in the Pacific although major differences may be noted for some species). If the length is from the literature or another researcher the source is stated in parenthesis. In some cases, the body length of shelled species is estimated from shells by comparison with photos of other specimens. In species where only shells are known, the shell length is given. In all cases, the maximum size should be viewed with caution for relatively rare species due to the small sample size.

The identification section provides a brief description of the species with emphasis on those characteristics that we believe are most useful in distinguishing it from similar-appearing species. It also discusses relevant variation.

The natural history section provides a brief discussion of distribution, habitat, diet, behavior and reproduction. All statements are based on the observations of the authors unless otherwise noted.

How common a species appears to be is influenced by the pattern of sampling, sampling techniques, etc. It may also vary with habitat and season. In addition, there is often a substantial difference between the numbers seen by divers and the actual numbers indicated by random sampling. For these reasons, it is difficult to establish a fixed definition for the terms used. Nevertheless, we will try to apply the following generalities:  rare--found less than 5 times by the authors, moderately rare--found 5 to 20 times by the authors; moderately common--found 20 to 100 times by the authors, common--found over 100 times by the authors. When used in conjunction with a designated habitat, the terms represent a rough extrapolation from smaller samples. In some cases, we may use such phrases as "common but rarely seen" with regard to species that are frequently found in quantitative sampling but seldom seen in the field due to their small size, cryptic coloration or retiring habits.

Exposure deals with the amount of wave action or surge in shallow water at particular sites and is somewhat subjective due to the complexity of those sites. However, the following examples provide a rough bench mark for our usage:  highly protected (Kaneohe Bay, Kahului harbor), protected (back-reef at Hekili Point, Kapalua Bay), moderately protected (Napili Bay, Honolua Bay), moderately exposed (Maliko Bay, reef crest at Hekili Point), exposed (Papawai Point, Black Rock, Maalaea Bay) and highly exposed (Alelele Stream, Nakalele Point). When animals extend to depths below the surge zone this convention may not apply.

Descriptions of behavior and egg masses are based on a limited number of anecdotal observations and should be regarded as tentative.

Most hatching times referred to as "in the laboratory" are based on egg masses held in small, shaded, covered dishes with water changed about twice a day. So, the average temperature probably approximated the mean surface water/air temperature at the time of observation at Camp Pecusa/Olowalu (with variation roughly tracking shaded air temperature "near the beach").

The distribution section lists the islands in Hawaii where, to our knowledge, the species has been found. It also lists where it is found outside Hawaii. Since sample sizes are often low and coverage incomplete, it should not be viewed as in any way comprehensive.

The taxonomic notes section offers a brief discussion of major issues affecting nomenclature, as well as major synonyms and name changes relative to well known Hawaiian guides. Links to Bill Rudman's Sea Slug Forum or other sites are routinely provided for further discussion. Also, the first Hawaiian sighting that we know of (based on specimens or photos) is credited even if a later date has been published as the first Hawaiian record in the literature.

The photo section lists the photographer for the photo at the top of the page and relevant data regarding the photographed animal (when known). The finder of the animal is credited if different from the photographer. When the photographer or finder is one of the authors, initials are used. If no finder is indicated the photographer is the finder.

The observations and comments section provides details of anecdotal observations that support or expand upon statements made in the remainder of the page. Internal links to the notes are provided for the convenience of the reader.

The additional photos section to the left includes thumbnails linked to more photos of the species. They may  provide other views or close-ups useful for identification, illustrate intraspecific variation, illustrate changes related to ontogeny (and other factors), document behavior or illustrate egg masses. Further photos that illustrate growth sequences, details, egg development, etc. may appear on the linked pages without appearing as thumbnails in the side bar. The gallery link at the bottom of the section, if present, leads to additional photos, usually taken by the authors, that are presented at a reduced size as a further aid to understanding variation.
Species list