Xenia garciae Bourne 1894
Creators: name: Halász, Anna
name: Mcfadden, Catherine S.
name: Toonen, Robert
name: Benayahu, Yehuda
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Animalia
Cnidaria
Anthozoa
Alcyonacea
Xeniidae
Xenia
Xenia garciae

description: Xenia garciae Bourne, 1894
Fig. 7
Xenia garciae Bourne, 1894: 475, plate 12, Figs. 13–14; Xenia garciae; Ashworth 1900: 520; Kükenthal 1902: 652–653; Gohar 1940: 100–101; Tixier-Durivault 1966: 363; Verseveldt 1970: 210, listed only; Benayahu 1990: 118, listed only; Reinicke 1997: 38–39.
Material. Type: BML 1921.11.18.1, Indian Ocean, Chagos-Archipelago, Diego Garcia, 1886, coll. G. C. Bourne.
Description. The colony is very small, its stalk is up to 5 mm high and undivided, with polyps tightly packed on the capitulum. Three rows of pinnules are aligned along each of the tentacle margins, 16–22 in the outermost row, separated by less than a pinnule-wide space.
Sclerites are ellipsoid platelets 0.009 –0.016 X 0.016 –0.021 mm in diameter (Fig. 7 a–d, n=20). A surface crest can occasionally be observed (Fig. 7a). The sclerites are composed of calcite rods arranged radially and assembled randomly within the sclerite interior (Fig. 7c). The rods are uniform in width throughout their length and provide a granular appearance to the sclerite's surface. Under SEM the sclerites are mostly fractured.
Remarks. The condition of the type of Xenia garciae is poor, probably due to inappropriate preservation; measurements of the colony and polyps could therefore not be made. According to Kükenthal (1902: 652–653), X. garciae features three rows of pinnules, 9–10 pinnules in the outermost row. Later, Gohar (1940) noted that X. garciae collected from the Red Sea, which was the first species to be reported from Hurgada, featured three rows of pinnules, 6–10 pinnules in the outermost row, and “spherical” sclerites, 0.018 –0.025 mm in diameter. That study also noted that the colonies are non-pulsating and that the species is known from Diego Garcia (Bourne 1894: 475), Maldives (Hickson 1903: 479), Malay Archipelago (Thomson and Dean 1931), and at several Red Sea sites (Ghardaqa, Shadwan Island and Qoseir). The above two descriptions do not correspond to the current findings due to the much smaller number of pinnules described. Reinicke (1997) raised doubts concerning the species' presence in the Red Sea since Gohar's material could not be examined by him. Furthermore, colonies referred to by Reinicke (1995) as X. garciae were found in this study to belong to the genus Ovabunda: O vabunda gohari (Reinicke, 1997) and O. arabica (Reinicke, 1995).
Similar species and conclusion. Both Xenia blumi and X. garciae feature three rows of pinnules, 18–20 pinnules in the outermost row and a similar sclerite microstructure. The current findings indicate that X. garciae occasionally features a small surface crest. Therefore, the two species should be considered as separate until further data on freshly collected colonies are available and the extent of these surface crests can be further investigated.
Distribution. Indian Ocean: Chagos-Archipelago.
description: Published as part of Halász, Anna, Mcfadden, Catherine S., Toonen, Robert & Benayahu, Yehuda, 2019, Re-description of type material of Xenia Lamarck, 1816 (Octocorallia: Xeniidae), pp. 201-239 in Zootaxa 4652 (2) on pages 213-214, DOI: 10.11646/zootaxa.4652.2.1, http://zenodo.org/record/3363653