Sansibia flava
Creators: name: Benayahu, Yehuda
name: Ekins, Merrick
name: Van Ofwegen, Leen P.
name: Samimi-Namin, Kaveh
name: Mcfadden, Catherine S.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Cnidaria
Anthozoa
Alcyonacea
Xeniidae
Sansibia
Sansibia flava

description: Sansibia flava (May, 1898)
Figures 1–4, 5A–B
Clavularia flava May 1898: 8; May 1899: 43–44, Plate I, Fig. 3.
? Clavularia flava Thomson & Henderson 1906: 402, Plate XXX, Fig. 4; Cohn 1908: 243; Hickson 1931: 175 (listed only).? Anthelia flava Molander 1921: 3 (listed only); Thomson & Mackinnon 1910: 171; Roxas 1933: 63; Tixier-Durivault 1966: 348–349, Fig. 317.
Anthelia flava Benayahu 1993: 14–15, Fig. 7.
Material examined. Holotype: Sansibar. ZMH C 2570, three fragments, Kokotoni, coll. Stuhlmann. Additional material. Kenya. SMNHTAU_ Co _32573, Kitungamwe, on Tanzanian border, 20 m, 5 February 2003, coll. Y. Benayahu; SMNHTAU_ Co _36076, Shelly Beach, Mtwapa Creek, Likoni, 9 m, 8 February 2003, coll. Y Benayahu; Madagascar. SMNHTAU_ Co _36001, Le Banc du Castor (12.851833° S, 48.426050° E), 22–24 m, 28 November 2012, coll. Y. Benayahu; SMNHTAU_ Co _36003, same details; SMNHTAU_ Co _36004, same details; SMNHTAU_ Co _36006, Le Banc du Castor, same details, 14–16 m, 28 November 2012, coll. Y. Benayahu; SMNHTAU_ Co _ 36007, same details; SMNHTAU_ Co _36073, 4 Frére (12.994250° S, 48.487467° E), 4–15 m, 1 December 2012, coll. Y. Benayahu; Zanzibar. BMNH 1912.2.25.5; Zanzibar shore, coll. J. A. Thomson; 1933.3.13.194, same details; BMNH, 1933.3.13.195, same details.
Diagnosis. The holotype, ZMH C 2570, consists of three fragments, probably of the same colony, each with a basal spreading membrane from which polyps emerge. One of the fragments (Fig. 2A) measures 20 x 10 mm and was closely examined. Its soft spreading membrane is approximately 1 mm thick and the polyps are flaccid. The polyp body is 6–10 mm long, depending on the degree of contraction, and the tentacles are 4–5 mm long. The pinnules are arranged in 3–4 rows, with up to 25 pinnules in the outermost row. They are short and pointed, approximately 1 mm long and 0.5 mm wide, with almost no space between adjacent ones.
The sclerites are highly abundant throughout the holotype. They are ellipsoid platelets mostly with a smooth margin, measuring 0.008 –0.013 x 0.013 –0.018 mm in diameter, and under SEM they are mostly fractured (Fig. 3A). The sclerites are composed of calcite rods, uniform in diameter of ca. 0.001 mm; the tips of the rods are more or less perpendicular to the surface of the sclerite, giving it a granular appearance (Fig. 3B).
Color. The ethanol–preserved holotype colonies are light cream.
Variation. The morphological features of the sequenced SMNHTAU colonies (see additional material above) resemble the holotype, except in size. They similarly feature a thin spreading membrane attached to a hard calcareous substrate or sand grains. The polyps can be up to 20 mm long (e. g. Fig. 2B, C: SMNHTAU_Co_36007) with their pinnules arranged in 2–4 rows with a variable number of pinnules on the outermost one (14–25). In all examined colonies the polyps and all the pinnules are expanded. The sclerites of SMNHTAU_Co_36007 are slightly larger compared to those of the holotype, up to 0.016 x 0.021 mm in diameter (Fig. 4A). Their smooth margin and granular surface microstructure (Fig. 4B) agree with the holotype. Our morphological examination of material from the BMNH (see additional material above), originally labeled as A. flava, confirms it to be S. flava (data not shown).
Color. The ethanol-preserved samples are cream or light brown.
Remarks. The current study is the first to re-describe the holotype of S. flava since its establishment by May (1898). The original description of the holotype material by May corresponds well to the current findings. The current SEM images of the holotype sclerites are the first to reveal their surface microstructure (Fig. 3), which is also considered to be diagnostic for several other xeniid genera (see Discussion below). It should be noted that the correct authority year of the species should be 1898 and not 1899, as erroneously appears in several publications (Thomson & Mackinnon 1910, Roxas 1933, Tixier-Durivualt 1966, Benayahu 1993, Alderslade 2000). Indeed, both of May’s publications (of 1898 and 1899) provide a similar taxonomic description of C. flava, but the former unquestionably should be prioritized. In addition, Hickson (1931) incorrectly referred to 1900 as the authority year of the species.
The other material examined in the current study exhibits some morphological variation with respect to the number of rows of pinnules and the number of pinnules in the outermost row. These findings further demonstrate the intraspecific variation of these characters, which are commonly used in the taxonomic literature for xeniid species delineation (e.g. Benayahu et al. 2021). It should be noted that the morphological features of SMNHTAU_Co_ 27901 collected from Sodwana Bay (South Africa) and identified as A. flava (see Benayahu 1993, Alderslade 2000) agree with the holotype of S. flava, and therefore its identification has been changed accordingly.
All of the sequenced samples (see other SMNHTAU material above) have been assigned to MOTU23 (McFadden et al. 2019), thus indicating that the geographic distribution of S. flava includes the western Indian Ocean coral reefs (Fig. 1). It is still questionable whether its distribution includes the Pacific Ocean, as suggested in several past studies based only on morphological identification (e. g. Taiwan: Benayahu et al. 2004, Hong Kong: Benayahu & Fabricius 2010 and Singapore: Benayahu & Chou 2010). Unfortunately, the latter samples are not appropriate for genetic analysis and, therefore, a conclusive taxonomic assignment of these samples still awaits future studies.
Living features. The encrusting live colonies feature a basal spreading membrane attached to the reef substrate, an expanded, relatively long, almost white, polyp body (Fig. 5A), and dark brown tentacles (Fig. 5A, B). The latter coloration is provided by the presence of numerous symbiotic algal cells.
Distribution. Zanzibar, Tanzania, Kenya, Madagascar, South Africa (Fig. 1).
description: Published as part of Benayahu, Yehuda, Ekins, Merrick, Van Ofwegen, Leen P., Samimi-Namin, Kaveh & Mcfadden, Catherine S., 2022, On some encrusting Xeniidae (Octocorallia): Re-examination of the type material of Sansibia flava (May, 1898) and a description of new taxa, pp. 421-444 in Zootaxa 5093 (4) on pages 424-428, DOI: 10.11646/zootaxa.5093.4.3, http://zenodo.org/record/5912731