Sympodium arbusculum, Benayahu & Ekins & Mcfadden, 2021

Benayahu, Yehuda, Ekins, Merrick & Mcfadden, Catherine S., 2021, Overview of the genus Sympodium Ehrenberg, 1834 (Octocorallia, Alcyonacea, Xeniidae), with the description of new species, revealing regional endemism, Zootaxa 5072 (4), pp. 324-350 : 328-331

publication ID

https://doi.org/ 10.11646/zootaxa.5072.4.2

publication LSID

lsid:zoobank.org:pub:810459A8-AF47-47A9-B5B6-BE45659B3E7F

DOI

https://doi.org/10.5281/zenodo.5748812

persistent identifier

https://treatment.plazi.org/id/FB5F8935-FFDA-FFAB-FF0C-F9F73CD0D0F9

treatment provided by

Plazi

scientific name

Sympodium arbusculum
status

sp. nov.

Sympodium arbusculum View in CoL sp. n.

Figs. 1 View FIGURE 1 , 2 View FIGURE 2 , 3A View FIGURE 3

Material. Madagascar. Holotype: SMNHTAU_ Co _36017, Ankaréa (12°50.054’S, 48°34.563.3’E), 6–9 m, 29 November 2012, coll. Y. Benayahu ; Paratypes: SMNHTAU_ Co 38226, five colonies, same details as the holotype; SMNHTAU_ Co _36015, same details; Tanzania, SMNHTAU_ Co _32919, Shundo (4°52’53”S, 39°18’10”E), 0–25 m, 10 December 2004, coll. Y. Benayahu GoogleMaps ; Kenya. SMNHTAU_ Co _31143, off Mombasa, Turning Buoy, 10 m, 16 February 2001, coll. Y. Benayahu & S. Perkol-Finkel ; SMNHTAU_ Co _31153, same details; SMNHTAU_ Co _31163, off Mombasa, Simon’s Corner, 20–26 m, 20 February 2001, coll. Y. Benayahu & S. Perkol-Finkel ; Kenya, SMNHTAU_ Co _31173, off Mombasa, Shelly Beach, 10–12 m, 20 February 2001, coll. Y. Benayahu & S. Perkol-Finkel ; SMNHTAU_ Co _31495, off Likoni, Shelly Reef (4°06.4’S, 39°41’S), 19 m, 9 March 2002, coll. Y. Benayahu ; SMNHTAU_ Co _31512, off Likoni, Wall (4°06.4’S, 39°42’E), 15–27 m, 2 February 2002, coll. Y. Benayahu GoogleMaps ; SMNHTAU_ Co _31590, off Likoni, Shelly Reef (4°06.4’S, 39°41’E), 19 m, 9 March 2002, coll. Y. Benayahu. GoogleMaps

Description. The holotype is an encrusting colony attached by a membrane to calcareous fragments, and measures 1.9 x 1.5 cm ( Fig. 1A View FIGURE 1 ). Its soft basal membrane is thin, <1 mm thick. Clusters of non-retractile polyps bud off at different levels, occasionally dichotomously, to form small branched groups of polyps ( Fig. 1A View FIGURE 1 ). Occasionally, individual polyps arise from the membrane between the clustered polyps. The polyps that are the most expanded are up to 4 mm long and the tentacles are up to 1 mm long. The poor preservation state of the sample prevents a precise pinnule count, but it is estimated to be a single row with up to 10 slender and pointed pinnules on either side of the tentacle.

The sclerites of the holotype are ellipsoid platelets, abundant throughout the colony, 0.010 –0.011 x 0.015 –0.017 mm in diameter ( Fig. 2A View FIGURE 2 ). They are composed of tightly packed calcite rods whose tips provide a uniform granular appearance to the sclerite surface ( Fig. 2B View FIGURE 2 )

Color. The ethanol-preserved colony is light cream..

Etymology. The species’ name is derived from the Latin ‘arbuscula’, bush, referring to the clustered arrangement of polyps.

Variation. The paratype SMNHTAU_Co_38226 comprises four colonies that vary in size: the smallest colony measures 1.0 x 0.5 cm and the largest one 3.5 x 1.5 cm ( Fig. 1B View FIGURE 1 : one of the paratypes). Groups of polyps comprising these paratypes range in number of polyps from 4 to 18, and are up to 20 mm long from the basal membrane to the tip of the uppermost polyp. The paratype SMNHTAU_Co_36015 comprises eight colonies or fragments that resemble the holotype, except in size. The dichotomous arrangement of the polyps is visible ( Fig. 1C, D View FIGURE 1 ). Both the dimensions of the paratypes’ sclerites ( Fig. 2C View FIGURE 2 ) and their surface microstructure ( Fig. 2D View FIGURE 2 ) correspond to those of the holotype ( Fig. 2A, B View FIGURE 2 ).

Remarks. The morphology of the colonies, and in particular the arrangement of the non-retractile polyps in clusters, is considered to be diagnostic of the species. The holotype was sequenced and subsequently assigned to MOTU38 ( McFadden et al. 2019).

Living features. The live brownish colonies feature clusters of expanded polyps ( Fig. 3A View FIGURE 3 ).

Distribution. Kenya, Madagascar, Tanzania.

Kingdom

Animalia

Phylum

Cnidaria

Class

Anthozoa

SubClass

Octocorallia

Order

Alcyonacea

Family

Xeniidae

Genus

Sympodium

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