Paragorgia arborea var. pacifica (Verrill, 1922)

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, and Calcaxonia - Part I: Introduction, species of Scleraxonia and Holaxonia (Family Acanthogorgiidae), ZooKeys 860, pp. 1-66 : 1

Paragorgia arborea var. pacifica (Verrill, 1922) Figure 3

Paragorgia pacifica (Verrill, 1922): G16-G18; plate VIII, figs 3, 4b.

Alcyonium arboreum Linnaeus, 1758: 803. Pallas, 1787: 164.

Paragorgia arborea (Linnaeus, 1758): 803. Milne Edwards 1857: 190. Broch 1912: 6. Hickson 1915: 548-549. Grasshoff 1979: 117 [and references therein]. Sánchez 2005: 15-20.

Paragorgia nodosa Koren & Danielsson, 1883: 19 [sensu Bayer 1956b: 70].

(?) Paragorgia nodosa Nutting, 1912: 99.

(?) Paragorgia regalis Nutting, 1912: 100.

Type locality.

Canada, British Columbia, Vancouver Island, Jervis Inlet, ~20 m.

Type specimens.

Holotype YPM-5373 [dry].

Material examined.

~1-2 lots (see Appendix 1: List of material examined).

Description.

Collection lot studied contains one branch fragment (Figure 3); in most respects, examination of fragment revealed characters that align with the description given in Sánchez (2005, pages 15-20). The branch is distinctive in its knobby aspect, but sclerites fall well within the parameters of morphology as discussed and shown in Sánchez (2005).

Etymology.

The variety name pacifica was presumably proposed in reference to the location/distribution of the species in the Pacific Ocean.

Common name.

Referred to frequently as "Bubblegum coral." Cairns et al. (2003) referred to Breeze et al. (1997) where this genus/species is also listed as "Rubber Trees" and "Strawberry Plants." Specifically, it could be called the "Pacific bubblegum tree."

Distribution.

Recorded from Alaskan waters, Bering Sea, ‘Albatross’, 54°02'40"N, 166°42'00"W, at a depth of 504 m; USNM 3315. Also, recorded from Unalaska to Kodiak, ‘Albatross’, 54°19'00"N, 159°40'00"W, taken by dredge, 114 m; USNM 3338. Bayer indicated (unpublished ms 2, Cairns 2009) that known distribution of this species was from the Bering Sea south to Vancouver Island (specimen collected by Mr Wm Spreadborough, at Ucluelet, Vancouver Island, BC, at a depth of 16 m, June, 1909. [Col. No. 51, Coelenterates, Victoria Memorial Museum, Ottawa]) on the east side of the Pacific, and likely over to Japan on the west; southern limit (at the time Bayer was writing) was unknown. Based on more recent work, including the review of systematics for the family by Sánchez (2005), this species, in the Pacific Ocean (a possible variant of P. arborea ), extends to at least the northern limit of the California Bight on the eastern side (at question, further south, at depth), and down into New Zealand waters on the Pacific Ocean’s western side.

Biology.

Specimens collected or photographed in the Monterey Bay Marine Sanctuary have harbored polychaete worms, purple in color (species identification not determined), with the worms wound around the branches of the colony ( Langstroth and Langstroth 2000). On a specimen examined from Mexico, Gulf of California, Baja, Bahia de Los Angeles, there was a complete over-covering of what may be some sort of grey colonial or zoanthid-type organism (the specimen was not included in the list of material examined, as the overgrowth of the zoanthids precluded any clear examination of the host gorgonian itself). A MBARI video clip, viewed on a visit to MBARI, had an excellent segment of this species heavily colonized by numerous basket stars, so many in fact, that the entire, large tree-like colony displayed a heavy growth of “hair.” According to Langstroth and Langstroth (2000), on a Paragorgia specimen, a feather star, Florometra serratissima , was seen clutching the gorgonian with its leg-like cirri. While this was seen in a lab setting, the feather star likely may have come with the gorgonian during the collection process. If so, other filter-feeding echinoderms might be seen living on/with these gorgonians in situ. Evidence from recent OCNMS expeditions, as well as numerous MBARI and NOAA video clips support this. Colonies living in deeper water grow very slowly in some areas and could be several hundred years old ( Andrews et al. 2005, Sherwood et al. 2005), reaching heights of several meters ( DeVogelaere et al. 2005). It is speculated ( Brancato et al. 2007) that these large, aged colonies provide critical habitat for such organisms as Northern Rockfish, Pacific Ocean Perch, species of King Crab, and Pacific Cod. An expedition undertaken by Olympic Coast NMS (May 2006) lent credence to this speculation.

Remarks.

Sclerite examination of the sample shown in Figure 3 agreed with those seen in Sánchez (2005: fig 9); the six-radiates distinctive of this species were confirmed. Verrill (1922), reporting on specimens of Paragorgia arborea , discussed the possibility of the existence of this variant. Bayer stated in his unpublished manuscript (ms 2, Cairns 2009)) that " P. arborea seems limited to latitudes of 40° or higher.... P. arborea seems to be truly bipolar, since no reliable finds have been made south of British Columbia in the Pacific. It is impossible to be sure that the species does not show equatorial submergence." Thus, "it appears that the genus Paragorgia , an inhabitant of cold waters,... whose various species occur at moderate depths in boreal and anti-boreal regions, follow the cool water to greater depths in low latitudes." Bayer additionally stated that a specimen obtained in British Columbia, as P. pacifica could be a variety of P. arborea . Kozloff et al. (1987) stated that Paragorgia pacifica is "the most commonly encountered gorgonian of" the Pacific Northwest region; "it has been called Paragorgia arborea Linnaeus, 1758." The final word comes from Sánchez (2005); he stated that a comprehensive review of North Pacific populations of P. arborea , "including type material and genetics is needed before reaching conclusions on P. pacifica and the differentiation of south vs. north P. arborea populations."

The California Academy of Sciences has approximately 30 lots of this, or other species, attributed to this genus; most specimens are from Alaska; as well, two are from the USSR, one is from Norway, and one is from Oregon. Nine of the remaining lots are specimens collected from California; most are from Monterey Bay, with one from the Davidson Seamount. Of these nine, only three have been identified as being this particular species. MBARI has extensive video records of this species from Monterey Canyon, as well as the Davidson Seamount. In the Moss Landing Marine Labs collection there is a small specimen of what may well be this species, collected in Monterey Bay, ~ 36°27'12"N, 122°04'02"W, ~450 meters; coll. G McDonald, 13 March 1974; C0067 [wet]. As well, there is an impressive, tree-sized dry specimen on display in the hallway near the museum door. (Collection data may be available for this specimen, but collection data could not be located.)

Based on multiple examinations of possible Paragorgia material in the SBMNH research collection, none (one exception) were examples of P. arborea var. pacifica ; numerous sclerite preparations never revealed the six-radiate sclerite form that is characteristic of this species; only a very few displayed eight-radiates. As well, no polyp sclerites were ever obtained. As most of the SBMNH specimens examined clearly lacked the “key” identifying sclerites, no request was made to obtain the holotype specimen from Yale Peabody Museum. P. arborea (though not the variety pacifica suggested by Verrill) is an accepted species in the WoRMS listings ( Cordeiro et al. 2018b). As well, the three following species are also accepted species in the WoRMS registry. These are included as they have been collected in very close proximity to the California Bight region. None however, are represented in the SBMNH collection and research indicated that they were never collected on any of the ‘Velero’ expeditions. In point of fact, there were no records of any specimens in the genus Paragorgia having been collected.