Unomia stolonifera
Creators: name: Benayahu, Yehuda
name: Van Ofwegen, Leen P.
name: Ruiz Allais, J. P.
name: Mcfadden, Catherine S.
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Cnidaria
Anthozoa
Alcyonacea
Xeniidae
Unomia
Unomia stolonifera

description: Unomia stolonifera (Gohar, 1938)
Figs. 1–5
Cespitularia stolonifera Gohar, 1938: 483–485, plate I, fig. 1; Utinomi 1950: 16; Utinomi 1959: 305.
Material. Type. Indonesia: BMNH 1889.5.27, Amboina, st. 233, shallow water, coll. H.M.S. Challenger, 1889. Additional material. Indonesia: RMNH. COEL. 42436, SW Sulawesi, Spermonde Archipelago, west of Lumu-Lumu Isl. (= 28 km NW of Ujungpandang), 4 o 58’S 119 o 12’E, coral reef, scuba diving, 27 May 1994, Bug. Prog. UNHAS-NNM. coll. B.W. Hoeksema & L.P. van Ofwegen; RMNH. COEL. 42437 details as above; Venezuela: ZMTAU Co. 38081, Valle Seco, Bahia Conoma, Estado Sucre, 4–6 m, 28 November 2012, coll. Juan P. Ruiz Allais, four specimens; ZMTAU Co. 38082 details as above, two specimens.
Description. The type, BMNH 1889.5.27, consists of four soft colonies attached by a spreading membrane to a skeleton fragment of branched Acropora stony coral and an additional colony similarly attached to a smaller fragment (Fig. 1A), each measuring approximately 3 X 4 cm. The spreading membrane overgrowing the calcareous substrate is clearly presented in Fig. 1B, in which the type colonies are viewed from the opposite side. The colonies ramify into a number of short branches up to 12–25 mm long, each with a polyp-bearing region on their upper part. Individual polyps are also found on the branches or on the stalk thus indicating the diffuse nature of the polypiferous part of the colony. Some of the polyps are damaged, mostly having lost their tentacles. The polyp body is up to 10–14 mm long and the tentacles up to 5–7 mm long. The pinnules are arranged in 3 rows and occasionally 2 rows, with 18–25 in the outermost row. The pinnules are almost completely contracted, 0.5 mm wide, with an approximately one pinnule-wide space between adjacent ones.
The sclerites are ellipsoid platelets, highly abundant in all parts of the colony, measuring 0.012 –0.015 X 0.018 – 0.021 mm in diameter (Fig. 2A). They are composed of calcite rods, uniform in diameter of about 0.001 –0.002 mm, and the tips of the rods are perpendicular to the surface of the sclerite (Fig. 2B). The ethanol-preserved type material is cream-white.
RMNH. COEL. 42436, is a flattened, very soft colony, 9 cm high and 6 cm wide, and attached to calcareous fragments by a spreading membrane (Fig. 1C). Its stalk is split into 5–6 short branches, each featuring a cluster of polyps; individual polyps are also found on the branches below these clusters. The polyp body is up to 10 mm long and the tentacles are up to 15 mm long. The pinnules are arranged mostly in 3 rows, or rarely in 2 rows, with 18–24 pinnules in the outermost row, exhibiting a gap of up to a pinnule-width between adjacent ones. Some pinnules are contracted and the fully extended ones are up to 2 mm long. The sclerites resemble those of the type, measuring 0.010–0.015 X 0.015–0.021 mm in diameter (Fig. 3). RMNH.COEL.42437 differs from RMNH.COEL.42436 only in size (Fig. 1D). Both ethanol-preserved colonies are light beige-white in color.
ZMTAU CO 38081 consists of four Venezuelan colonies (Fig. 1E). Their morphology resembles the type material, featuring a diffused polypiferous part of the colonies. The polyp body is up to 25 mm long and the tentacles up to 10 mm long, bearing pinnules arranged in 3 rows with 20–25 pinnules in the outermost row and a gap of up to a pinnule-width between adjacent ones. The sclerites also resembles those of the type, measuring 0.014 –0.017 X 0.018 –0.025 mm in diameter (Fig. 4). ZMTAU CO 38082 (not depicted) resembles ZMTAU CO 38081.
Underwater photographs of live colonies taken at Valle Seco, Bahia Conoma, Estado Sucre, Venezuela, reveal the diffuse nature of the polypiferous part of the colonies (Fig. 5A). The live polyps feature elongate dark brown tentacles due to the symbiotic zooxanthellae as well numerous sclerites as presented in Fig. 5B. Individual polyps are found on the stalk, below the level of the polypary (Fig. 5C, D).
Remarks. The material from Sulawesi (RMNH.COEL. 42436, 42437) resembles the type of Unomia gen. n. (BMNH 1889.5.27). Notably, the invasive xeniid from Venezuela, which was originally identified as a “xeniid with close genetic affinities to Xenia membranacea Schenk, 1896 ’’ (Ruiz Allais et al. 2014), matches well the above material. The freshly collected and ethanol-preserved specimens from that site enabled the molecular analysis and placement of the species in the phylogenetic tree. Consequently, the taxonomic status of this peculiar invasive soft coral is now confirmed to be U. stolonifera (Gohar, 1938).
Distribution. Indonesia (Ambon, Sulawesi), Venezuela.
description: Published as part of Benayahu, Yehuda, Van Ofwegen, Leen P., Ruiz Allais, J. P. & Mcfadden, Catherine S., 2021, Revisiting the type of Cespitularia stolonifera Gohar, 1938 leads to the description of a new genus and a species of the family Xeniidae (Octocorallia, Alcyonacea), pp. 330-344 in Zootaxa 4964 (2) on page 333, DOI: 10.11646/zootaxa.4964.2.5, http://zenodo.org/record/4709507