Swiftia pacifica (Nutting, 1912)

Horvath, Elizabeth Anne, 2019, A review of gorgonian coral species (Cnidaria, Octocorallia, Alcyonacea) held in the Santa Barbara Museum of Natural History research collection: focus on species from Scleraxonia, Holaxonia, Calcaxonia - Part III: Suborder Holaxonia continued, and suborder Calcaxonia, ZooKeys 860, pp. 183-306 : 192-199

Swiftia pacifica (Nutting, 1912) Figures 3A, B , 4 A–D , 5A, B , 6 A–F , 21A, B , 22 A–D , 23A, B

Swiftia pacifica (Nutting, 1912): 96, 97, pl 14 (figs 2, 2a) and pl 21 (fig. 6) [= Stenogorgia pacificus Nutting, 1912]: Muzik 1979: 168-173, fig. 26, pl XXVI.

Callistephanus pacificus Nutting, 1912: 96, 97.

Allogorgia exserta Verrill, 1928: 8.

Swiftia rosea pacificus (Nutting, 1912): stat. nov. Madsen 1970: 8.

Type locality.

For holotype, unknown (erroneously labeled); for type, ‘Albatross’ Station 4781, 52°14'30"N, 174°13'00"W, south and east of the Bering Sea. (See Remarks below.)

Type specimens.

Holotype USNM 49513 (colony portion only); Type USNM 30024; both specimens were examined.

Material examined.

~23 lots (see Appendix 3: List of material examined).

Description.

Colony moderately sized (up to 18-19 cm tall), planar, flabellate, flexible, rubbery in appearance ( Figure 3A ); branches nearly forming net-like reticulations, but usually not anastomosing; generally, moderate open appearance to branches. Main stem extends upwards some few cm (above base), 1.0-2.0 mm wide; branches from main stem opposite or alternate, coming off at 45° to 90° angles, then tending upwards; distance between branches 0.5-2.0 cm; terminal branches to 2.0 cm long, l.0 mm in diameter. Polyps lateral (mostly alternate, sometimes opposite), very few on front, with back generally free of polyps, thus flat; polyps conical (sometimes tubular), three, four or five per cm, arising from small mounds ( Figure 3B ); anthostele 0.5-2.0 mm H, 1.0-2.0 mm W (seeming rather broad and boxy), anthocodiae preserved exert up to 2.0 mm long, but often appearing as dense tuft with 1.0 mm or less showing above polyp mound. At distal end of terminal branches, two (or two pair) oppositely disposed polyps. Color of colony bright to deep crimson or muddy red (brick-red) in life, but both darker and lighter red (dull pink) colonies occur; polyps sometimes dark greenish-grey; sclerites bright red or orange (rods) to pale pinkish-red (most common color, usually true of spindles and capstans). Sclerites ( Figures 4 A–D , 5 A, B, 6 A–F) symmetrical; unilaterally developed superficial capstans and spindles, 0.08 to 0.17 mm long in coenenchyme; flatter warty spindles to 0.35 mm in layer below; also eight radiates. Axial sheath sclerites short (to 0.12 mm), narrow-waisted, blunt-ended. Anthocodial bases can have numerous prominent blunt bars (fingerbiscuit rods, in shape comparable to a bacterial rod), curved or straight ( Figures 5B , 6D ); arranged transversely at bases, more longitudinal at distal end. Examination of multiple specimens did not always reveal presence of rods, but when present, very obvious. Pinnular scales 0.06-0.1 mm long.

Etymology.

Species name likely refers to locality where type specimen was collected, outer Aleutian Islands, Alaska in the North Pacific.

Distribution.

North Pacific Ocean, Aleutian Islands, Alaska down to California (not a common occurrence), and from Alaska down through western Pacific to Hawaii. Range determined from collection location information provided with specimens examined (see Appendix 3: List of material examined).

Biology.

Usually bathyal, but depth range extends from ~18 to ≥ 2,000 m, based on depth information provided with specimens examined.

Remarks.

Bayer made personal notations in his copy of Nutting (1909); species is quite similar to Swiftia kofoidi . In overall shape, this species ranges from a rather open-spaced and delicately appearing colony (rarely) to one that seems bulkier. The zig-zag profile is evident but is much more rounded (less jagged-looking) than that of S. kofoidi . Polyp mounds in S. pacifica are somewhat lower, more rounded than those seen in S. kofoidi . In Nutting’s 1912 description, he noted this species’ "very close resemblance to Calllistephanus koreni Wright and Studer" but also added that "(g)eographical considerations render it unlikely that the two are identical." Madsen (1970) noted that the species described here so closely agreed "with the Scandinavian rosea (it too, has radiate capstans among the spicules) that it is reasonable to consider it its amphiboreal representative, and to regard it as a subspecies of rosea , stat. nov. [ Swiftia rosea ( Grieg 1887)];" an example of a discontinuous circumboreal octocoral.

Examination of specimens collected in the Gulf of Mexico, 2009 (provided by P Etnoyer, NOAA’s National Ocean Service Office, South Carolina), indicated Madsen may have been correct. Three specimens were sent (without collection data). Sclerite preparations were performed, and specimens were tentatively identified as S. pacifica ; when informed (pers. comm. from A Quattrini, then a doctoral candidate, Temple University) that these three were actually collected from the Gulf of Mexico, further investigation was warranted. Specimens of S. pallida Madsen, 1970 had been examined and sequenced (via barcoding of those specimens), and a close match was found between S. pallida specimens and other lots of the same specimens examined. Referring back to Madsen’s (1970) discussion, S. pallida was considered by Madsen to be, at most, a subspecies of Swiftia rosea ( Swiftia rosea pallida Madsen, 1970), of the north Atlantic, based on the color of its colony form (pale gray) and sclerites (colorless). S. pacifica from the Pacific Ocean, examined here (considering Madsen) looked very similar to the species S. rosea (which could certainly be the correct species identification for the three specimens from the Gulf of Mexico sent by Etnoyer) in its colony color, branch detail, arrangement of polyps and shape of its sclerites. It appeared that S. pacifica (eastern North Pacific), S. rosea of the Atlantic and its subspecies, S. pallida (a northern Atlantic bathyal form) were strongly related. S. rosea is the nominate form, found not only in the bathyal North Atlantic, but also in the Scandinavian sublittoral ( Madsen 1970). It would appear that the species described here could be the Pacific Ocean extension (of the Atlantic species S. rosea ) in its distribution, having moved into the Pacific Ocean via waters circumscribing the North Pole. It can be inferred that as S. pacifica appeared in the Pacific, it dispersed down the western coast of the North American continent (at least as far as, generally, central California), just as S. rosea has apparently spread across the north Atlantic and down the eastern side of the North American continent (and presumably, into the Gulf of Mexico, perhaps as a new subspecies). The WoRMS Database (Cordeiro et al. 2019) shows the accepted status of this species.

Muzik (1979) noted discrepancies regarding locality for the holotype. The specimen is housed in the Bishop Museum, Hawaii (as Allogorgia exserta , #101), with a portion of it housed at NMNH (USNM 49513). This specimen "agrees in details of color, sclerites, and polyp size and shape with the type from Alaska of Swiftia pacifica (USNM 30024) collected from the Aleutians in 1906 and described by Nutting in 1912. One can conclude that there was an error in the locality of the so-called Hawaiian specimen. It is entered in the Bishop Museum catalog as ‘Albatross’ 2742 without locality. Entry 2741 is from Station 3353 off Panama. Prior to that station, the ‘Albatross’ had been collecting in the Pacific Northwest, so it is conceivable that this S. pacifica was collected there and later confused." It appeared that normal range for Swiftia pacifica is from central/northern California northward, but occasionally may appear south of that range. CAS has thirty cataloged records from this genus; of these, eleven lots are from Alaska, and are likely Swiftia pacifica .

There appeared to be a distinct morphological trend, from southern to northern waters, along the California coast up through the coastal areas of Oregon, Washington and Alaska that required discussion; a proposed explanation for the range distribution of this species follows the descriptions of all species (with red color) found in or near the Bight covered in this paper. Briefly, an extensive examination of colonies collected from Baja California to the remote northern aspect of the Bering Sea (see Appendix 3: List of material examined) revealed a very distinctive trend in the appearance of colonies and sclerites from south to north. The sequential trends seen within the two species, S. kofoidi and S. pacifica (or morphs of one) are discussed in the Further Remarks section (along with variation in sclerite morphology of other eastern Pacific Swiftia species). The observation of this phenomenon has never been discerned or noted previously.

Figures

Figure 3. Swiftia kofoidi [? Swiftia pacifica] (thicker dark red " morph "), SBMNH 232036. A Colony measures 6.0 cm tall, 5.5 cm broad at widest point, demonstrating zig-zag appearance of branches due to calycular placement B Branch close-up, showing placement of prominent conical calyces on branches; calyces measure ~ 1.0 mm tall.

Figure 4. Swiftia kofoidi [? Swiftia pacifica], SBMNH 232036, SEM image. A Truncated, jagged disk-spindle / capstan-like forms B Elongated spindles C Might be a typical " fingerbiscuit-rod " form typical of the genus; seen very rarely, if at all in this species D An irregular spindle.

Figure 5. Swiftia pacifica, specimen 41 - 39 - 1 (Alaska Fisheries Service, Gulf of Alaska); looking in same form of that seen in Figure 3, light microscopy arrays. A (4 x) showing variety of sclerites, particularly the characteristic " fingerbiscuit-rod " seen in the genus Swiftia. Sclerites from specimen examined for Bob Stone, Alaska Fisheries Service B Higher magnification, 10 x, showing all sclerite forms, including obvious anthocodial fingerbiscuit-rods. The larger spindles measure ~ 300 µm long, smaller spindles of ~ 200 µm, and the rods range from 308 - 370 µm in length.

Figure 6. Swiftia pacifica, specimen 41 - 100 A- 2 (Alaska Fisheries Service, Gulf of Alaska, via Bob Stone), SEM image. A Long spindles B Jagged disk-spindle / capstan-like sclerites C Thick, elongated rod-like spindles D Anthocodial " fingerbiscuit-rod " forms characteristic of the genus E Irregular spindles F Odd irregular spindles.

Figure 21. Colonies collected / examined from the northern end of the geographic continuum, confirmed identification as Swiftia pacifica. A OCNMS OC 06 _ 0531, EPI 127 B NOAA 41 - 39 - 1 (AB 17 - 0010). Image of specimen shown in A provided by Mary Brancato (OCNMS); specimen shown in B provided by Robert Stone (NOAA).

Figure 22. Common sclerite forms seen in colonies of S. pacifica collected from the northern portion of the geographic continuum, using standard light microscopy. A NOAA 41 - 39 - 1 (AB 17 - 0010) B NOAA CB 50003 - 021 C, D NOAA CB 50003 - 032.

Figure 23. Sclerites from a specimen collected in the northern portion of the geographic continuum, in SEM. A, B From NOAA 41 - 100 A- 2 (AB 17 - 0009).