Swiftia simplex (Nutting, 1909)

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 : 199-203

Swiftia simplex (Nutting, 1909) Figures 7 , 8A, B , 9A, B , 10 A–H , 24 A–D , 25A, B , 26 A–C , 27A, B

Psammogorgia simplex Nutting, 1909: 720, pl 88 (figs 4, 5), pl 90 (fig. 4).

Type locality.

[USA], California, Santa Cruz Island, bearing N 35°E, 7 miles off Point San Pedro, ~ 34°02'02.76"N, 119°31'11.77"W, 447-510 fm [813-927 m].

Type specimens.

Syntype USNM 25431 and USNM 43130 [both wet]; both specimens were examined.

Material examined.

~24 lots (see Appendix 3: List of material examined).

Description.

Colony ( Figures 7 , 8A ) straggling, whip-like, not always erect; branched slightly, mostly unbranched; largest specimens ~13+ cm tall. Stem round, slender, of uniform diameter throughout. On stem/branches, polyps uniformly distributed on all sides, not crowded ( Figure 8B ), up to 2.0 mm apart; tubular, small, ~1.0 mm high, usually higher than broad; when polyps contracted, nearly flush with branch surface. Coenenchyme moderately thick; color of living colony, including polyps, salmon, brick reddish-pink (commonly) to coral-red throughout; sclerites reddish-pink; rods reddish-orange; sometimes long, warty spindles colored and colorless. Sclerites ( Figures 9A, B , 10 A–H ) of three main kinds: 1) small double-spindles, rosettes, stars and/or small clubs, found mostly in superficial layer of coenenchyme (all much less numerous than second kind; clubs much less numerous than other kinds); 2) larger spindles, slender, pointed, some slightly curved, covered with regularly distributed small warts ( Figure 10 A–C ); 3) not always numerous, but when present, very conspicuous, colored anthocodial rods (fingerbiscuit rods; Figures 9A, B , 10H ); moderately to heavily warted, much shorter than long spindles, longer than first type. Polyps, generally, with spindle-shaped sclerites in walls and near/on tentacular bases, arranged more or less in chevrons. Otherwise, longitudinally arranged.

Etymology.

Earlier genus designation (Nutting, 1909), psammo - = sand); simplex - = simple, perhaps referencing the very simple, usually unbranched colony, found generally on soft-bottomed sites. However, no derivation for species name given in Nutting’s (1909) description.

Common name.

Whip coral (suggested: Brick-red whip coral).

Distribution.

Kükenthal (1919), in Chun: California, coast to abyssal. Total distributional range (surmised from collection location data reported by various institutions) extends from southern California Channel Islands (and further west--San Juan and Rodriquez Seamounts), up the coast of California (Monterey Bay, Carmel Canyon), sparsely along Oregon coast (Tillamook Head, Columbia River), to Washington coast (Grays Harbor, Quinault Canyon, Queets; general site locations off Oregon and Washington gleaned from NMNH material), up to Gulf of Alaska, found on seamounts and elsewhere (NMNH material, Alaska Fisheries Service). Fairly recent collection event (2008, Olympic Coast National Marine Sanctuary) produced at least one sample that may be this species, collected at ~ 48°07'53"N, 125°05'20"W at 335 m.

Biology.

Appears to prefer at least subtidal depths, generally deeper, according to collection location data; frequently encountered on Seamounts (~190-900 m). MBARI T630-A13 had attached to it what appeared to be a cluster of white eggs (cluster identity not determined); these flexible branch strands, projecting up into localized water currents, would make good attachment sites for eggs needing oxygenation and/or flow to keep them clean, being suspended above muddy bottoms found at depth.

Remarks.

CAS has three specimens (likely this species), all from northern California (Cordell Bank, W of Point Reyes, CAS-IZ-96739; off Pigeon Point in San Mateo County, CAS-IZ-96744 and Eel River Canyon in Humboldt County, CAS-IZ-96758), labeled as Euplexaura simplex . This is a hitherto unknown application of a genus name, done by D Harden in the early 1970s (likely, an attempt to be comparable with the then named Euplexaura marki ). This genus designation is incorrect; the specimen is the species Swiftia simplex . While Nutting (1909) placed it in the genus Psammogorgia Verrill, 1868a, geographic location of specimen(s) he described, geographic locations of specimens examined here, appearance of sclerites, along with molecular work conducted by M Everett et al. (2016), do not warrant that species designation either. While the WoRMS Database (Cordeiro et al. 2019) did indicate an accepted status for this species designation under the genus Swiftia , it also showed accepted status for the species as Psammogorgia simplex (Cordeiro et al. 2018). Based on the genus description for Psammogorgia by Verrill (1868a), Bayer (1958) on the morphological characters mentioned above and discussion provided by Bayer and Deichmann (1960), which also discussed the probability of appearance in the Panamanian province, material examined in this work warrants placement in the genus Swiftia , not in the genus Psammogorgia .

Sclerite examinations revealed a few individual colonies (several species) in the genus Swiftia (such as that shown in Figure 8 ), with minimal/no fingerbiscuit rods. Nothing examined and identified as Chromoplexaura marki ( Kükenthal, 1913) (species closest in superficial colony appearance) ever displayed these rods, as expected for this genus. It was easy to understand how identification done in the field, on in situ colonies (with water depth distorting color), could label colonies from the two species (this and C. marki ) as the same organism. Current examinations discussed here shed some light on the confusion. The explanation provided regarding S. pacifica in Further Remarks section, is an attempt to clarify (and explain) why some colonies of Swiftia have scleritic anthocodial rods and others do not.

California specimens identified from the genus Euplexaura (now the genus Chromoplexaura Williams, 2013) on several MBARI video clips that were viewed could actually be this species. C. marki (which this species can so closely resemble), is usually bright deep red, with white or pale yellow anthocodiae/polyps ( Kükenthal 1913, 1924; also Johnson and Snook 1927) but not always (see discussion, Part II, this work) while this species is a dull pinkish to brick red color, with colony coenenchyme and anthocodiae/polyps the same color; sclerites are very different for the two genera. It is likely that MBARI is seeing both this species and C. marki , but not able to clearly distinguish between the two due to color distortion at depth under field conditions, if not collecting.

A specimen (R1159_EPI_164_0015) collected by Olympic Coast National Marine Sanctuary in 2008 superficially appeared to be this species; polyps were mostly contracted into very round, prominent mounds, although these had larger dimension than that given in the above description (tentacles were more or less the same salmon color as the coenenchyme, but polyp bodies, closely proximal to branch, were white when dissected out). Based on further examinations, specimen was tentatively identified as Swiftia spauldingi (Nutting, 1909); however, lack of fingerbiscuit rods points in the direction of Chromoplexaura marki . Recent DNA sequencing (communications with M Everett, NOAA affiliate, 2013-2014) indicated that some Swiftia species might need subdividing (three different species or variants a possibility).

Figures

Figure 7. In situ shot, identified as Swiftia simplex. This is what one would expect to see of live colony. Notice strong similarity to that seen in Figure 28, Part II. As specimen was not collected, identification cannot be confirmed. Image (02 _ 57 _ 27 _ 20) courtesy of Lonny Lundsten and Kim Fulton-Bennet, " (c) 1992 MBARI. "

Figure 8. Swiftia simplex, SBMNH 422979. A Entire colony, ~ 21 cm long, diameter ≤ 3 cm, including calyx B Branch close-up showing calyx placement on branch. Scale bar: 3 cm (A).

Figure 9. Swiftia simplex, specimen 81 - 99 B- 1 (Alaska Fisheries Service), light microscopy arrays. A 4 x magnification, showing long, slender spindles and anthocodial fingerbiscuit-rods B 10 x magnification of sclerites, emphasizing fingerbiscuit-rods of anthocodium. These rods measure between 340 - 350 µm, while long, thin spindles measure between 430 - 500 µm. Specimen provided by Bob Stone, Alaska Fisheries Service.

Figure 10. Swiftia simplex, specimen 81 - 99 B- 1, SEM image. A Elongated spindles B Moderate-length spindles C Shorter spindles D Thick, elongated rod-like spindles E Less jagged double-disk / capstan-like forms F Tiny, odd spindle G Irregular spindles H Anthocodial " fingerbiscuit-rod " forms typical of genus. Alaska Fisheries Service.

Figure 24. Colonies collected / examined from throughout the geographic continuum (shown A-D from south to north), identified as Swiftia simplex. A SBMNH 422979 B NOAA CB 34013 C NOAA CB 34212 - 039 D NOAA CRW _ 3636 8; 35 cm H x 17 - 20 cm W. Image C Courtesy of Ewann Berntson (NOAA, WA); image D Courtesy of Robert Stone (NOAA, AK).

Figure 25. Sclerite arrays of S. simplex seen using light microscopy. A SBMNH 422979 B NOAA 81 - 99 B- 1 (AB 12 - 0127).

Figure 26. Sclerites of S. simplex in SEM. A NOAA CB 34011; A 1 - sclerites from coenenchyme, A 2 - sclerites from polyp tentacles B NOAA CB 34212 - 039, primarily coenenchymal sclerites C Also from CB 34212 - 039, primarily sclerites from the polyp. All SEM images in this figure prepared by Carla Stehr (NOAA), provided by Ewann Berntson (NOAA).

Figure 27. Further sclerite arrays in SEM, for a specimen from the far northern end of the continuum. A, B From NOAA 81 - 99 B- 1 (AB 12 - 0127).

Figure 28. Thesea, spp., SBMNH 422414. A Colony 23 cm from base attachment point on rock to tip (attachment was very tenuous; rock now separated from colony) B Closer view of branches, branch tip and pattern of calyces on branch surface.