Hemicorallium Gray, 1867

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

Genus Hemicorallium Gray, 1867

Madrepora (pars) Linnaeus, 1758: 797.

Corallium [ ächte rothe Steincoralle] Müller in Knorr, 1766: Delic. Nat. 1: 7, pl A I, figs 1, 2; 23, pl A VII, fig 1; 24, pl A VIII, figs 2-4; 127 (pars); nec. pp 9-13, 25, 128.

Isis (pars) Linnaeus, 1767: 1288.

Nec Isis Linnaeus, 1758: 799.

Nec Corallium Burman, 1769: [3] (= Isis Linnaeus, 1758).

Corallium Cuvier, 1798[1797]: 673. Lamarck 1801: 378. Dana 1846: 640-641. Gray 1860: 393; 1867: 126. Ridley 1882a: 221-222, 225. Kishinouye 1903: 626; 1904; 28; 1905: 27. Hickson 1905a: 268; 1907b: 13c1, 2. Kükenthal 1919: 743, 828, 902. Aurivillius 1931: 22. Bayer 1950: 61; 1956b: 70, 73; 1964b: 466-467;? 1993: 17; 1996b: 206, 213. Bayer and Cairns 2003: 222, 224. Tu et al. 2016: 1006.

Pleurocorallium Gray, 1867: 126. Ridley 1882a: 221-222. Johnson 1898: 421; 1899: 59. Kükenthal 1924: 47, 52. Bayer 1956b: 74; 1964b: 467. Bayer and Cairns 2003: 222. Figueroa and Baco 2014b: 83. Tu et al. 2015a: 302; 2015b: 173; 2016: 1022-1023.

Hemicorallium Gray, 1867: 126. Ridley 1882a: 221-222. Johnson 1899: 59. Kükenthal 1924: 47, 52. Bayer 1956b: 74; 1964b: 467. Bayer and Cairns 2003: 222. Ardila et al. 2012: 254. Figueroa and Baco 2014b: 83. Tu et al. 2015a: 302; 2015b: 173; 2016; 1010-1011.

Type species.

Madrepora rubra Linnaeus, 1758 (by subsequent monotypy, the first species being assigned by Lamarck 1801).

Diagnosis.

Sclerites of cortex numerous, regular capstans, often modified with six, seven or eight radii; or as double clubs (only some species), crosses and opera glasses; long spindles present in tentacles. Without axial pits bearing beaded rims beneath autozooids. Autozooids prominent, non-retractile (when contracted cannot fully retract into cortex) and ovate-cylindrical, usually distributed on one side of colony.

Etymology.

Bayer (1956b) stated that the name Corallium "is an old name of dubious origin, going back to the ancient Greeks, classically applied to the red coral of commerce, the 'true red stony coral’.”

Remarks

. An interesting genus; its connection to human enterprise and profit make it so. Collectively, "pink coral, red coral, noble coral, angel skin coral, Sardinia coral, midway coral" (CITES proposal, Convention of the Parties, CoP14 Prop. 21, June 2007) has had a long history, with the primary focus on harvesting of the coral for profit. At least one proposal, and multiple CITES conferences over the years (2007, 2010, 2013), have made this genus a focus of discussion. Numerous articles have been published concerning the impact of harvesting, management issues, etc. ( Tsounis et al. 2010, 2013, to name but a couple).

Because all species of coral in this genus tend to form tall, tree-like colonies, they likely increase three-dimensional complexity of the habitats they are found in and consequently, increase biodiversity where they occur. These colonies could easily provide valuable microhabitat for sessile, associated commensal invertebrates ( Baco and Shirley 2005, Baco 2007), protecting them from strong currents and predators. With regards to species occurring in the Pacific Ocean, "one of the more notable commensal relationships is the association of polynoid polychaetes with species in (this genus). Each Corallium species appears to have its own species of polynoid polychaete, which can reach high densities within individual colonies" ( Baco 2007). They would also provide structural relief that fishes and mobile invertebrates could use as feeding, spawning and resting grounds (CITES proposal, Convention of the Parties, June 2007). Thus, they contribute far more to their natural living situation than perhaps had been considered when commercial harvesting for species in this genus was first instituted.

A number of species in the genus Corallium have recently been transferred to the genus Hemicorallium (encompassing species discussed here; Cordeiro et al. 2019); this is based on the work of Tu et al. (2015a, b, 2016). Species in the genus Hemicorallium are represented in the SBMNH collection by a single specimen, SBMNH 471940 (likely Hemicorallium ducale ; see Appendix 1: List of material examined), but three species have been recorded (collected west of the California Channel Islands), in proximity to the western boundary edge of the Bight (location data for specimens housed at NMNH). The California Academy of Sciences has seven separate lots of specimens in this genus. Generally, all are from the Hawaiian Islands, with the exception of one. That one, identified only to genus, is from California, Davidson Seamount, 128 km SW of Monterey, taken at a depth of 1481 m, 21 May 2002. Further documentation of the presence of Hemicorallium in or near the California Bight is needed; in consideration of their rarity and commercial value, their presence would need to be very carefully monitored.