Hemicorallium regale (Bayer, 1956)

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

Hemicorallium regale (Bayer, 1956)

Corallium regale Bayer, 1956b: 70, 73-76; 77-78; figs 5c; 7 e–g. Bayer and Cairns 2003: 224.

Synonyms.

(see Remarks section below.)

Material examined.

No material in SBMNH collection (see Appendix 1: List of material examined).

Remarks.

Around the Pacific, from Hawaii (holotype, USNM 49520) to offshore seamounts some miles west of California coast (outer edge of Bight western boundary, USNM 94460), certainly at substantial depth (based on specimens housed in NMNH collection). Not enough specimens examined (or collected with attention to specific collection locations) to determine extent of north-south range. Bayer commented (1956b), "of all the Hawaiian precious corals, C. regale has the best color and might be of commercial value if it could be fished in quantity." Thin, calcareous extensions of axis extending outward to thick coenenchyme can support expansion of coenenchyme near sides of branches as recurved flaps, a distinctive feature. These can form tunnels inhabited by polychaete commensals ( Baco and Shirley 2005, Baco 2007). Could be given the common name "Regal red coral."

Several species in the now updated genus Hemicorallium , including this one, found within the Hawaiian archipelago (and elsewhere in the western Pacific, including international waters) have been the focus of commercial exploitation (then recognized as species in the genus Corallium ). Based on reports made public by CITES, regarding "consideration of proposals for amendment of Appendices I and II" (2007, 2010) and Bruckner (2009), there was much discussion, and confusion, as to whether this species (using older genus designation) was valid and/or whether it could be synonymous with Corallium laauense (misspelled as C. lauuense ). Grigg and Bayer (1976: 169) and Grigg (2002: 17-19) specifically mentioned C. regale and/or C. laauense as separate species. CoP14 Prop. 21 (CITES, 2007) listed this species as a potential synonym for C. laauense ; this based on Baco and Shank (2005: 664). However, Baco and Shank (2005) did not treat this species as a synonym of C. lauuense (note the misspelling), but a comment they made regarding the work of Grigg (2002) may have inadvertently lead some to assume that was the case. Cairns (CITES, 2007) did not consider these two taxa to be synonymous and Bruckner (2009: 321) also discussed these taxa as two separate species. Bruckner indicated that although he discussed them as two separate species, "these 2 species may be synonymous." In the document, Proposal, CoP15 Prop. 21 (CITES 2010), C. regale was still shown as a synonym of C. lauuense (sic); note the following statement: " C. lauuense and C. regale are listed as separate species in the US Precious Coral Fishery Management plan, but these species are usually considered synonymous ( Parrish 2007)". Again, C. laauense and C. regale were treated as synonymous; however, regarding C. regale , Baco and Shank (2005) stated: " C. lauuense was previously misidentified and referred to as C. regale which is not an indication of synonymy. There may still be some unresolved taxonomic problems concerning these two species." Additionally, " Bayer and Cairns (2003) differs from the SS species list in a number of ways: C. boshuense , C. niveum , C. porcellanum , C. pusillum , C. vanderbilti , and C. variabile are not mentioned; C. regale is treated as valid." (CITES 2010); of these species, C. boshuense and C. variabile have been moved to the genus Hemicorallium ( Cordeiro et al. 2019) in the WoRMS Database. The final implication was that Corallium sp. was found throughout "the Hawaiian archipelago and into the Emperor Seamount Chain" ( Baco 2007), but that the certainty of species identification was still in question.

In studying Bayer’s original 1956 description of C. laauense (correctly spelled) and C. regale , no determination could be made as to why these two were linked as synonymous. The now recognized species Hemicorallium regale has many double club sclerites, while H. laauense has none. As well, the entire colony of H. regale , as well as the axis, is pink, while the colony color of H. laauense is white or very faintly pink with a white axis. SEM images are on file ( Bayer’s personal collection), SEM #2283, USNM 94460.

The work by Tu et al. (2015a, b; 2016) resulted in most species of Corallium being placed in the genus Hemicorallium . WoRMS ( Cordeiro et al. 2019) confirms the placement of the species discussed here: H. ducale , H. imperiale , H. regale (as well as H. laauense ); all are listed as accepted, separate species.