Euplexaura plana, Namin, Samimi & Ofwegen, Van, 2009

Namin, Samimi & Ofwegen, Van, 2009, Some shallow water octocorals (Coelenterata: Anthozoa) of the Persian Gulf, Zootaxa 2058, pp. 1-52 : 25-28

publication ID

https://doi.org/ 10.5281/zenodo.186743

DOI

https://doi.org/10.5281/zenodo.6220182

persistent identifier

https://treatment.plazi.org/id/03A36F53-CA79-5A75-F0EC-FB07FF1F6BAF

treatment provided by

Plazi

scientific name

Euplexaura plana
status

sp. nov.

Euplexaura plana View in CoL n. sp.

( Figs. 2 View FIGURE 2. a – b d, 17)

Material: Holotype, RMNH Coel. 38778, Farur Island, coll. S.A. Mohtarami, 2006.

Description. The holotype is 15.5 cm high and 27 cm wide ( Fig. 2 View FIGURE 2. a – b d). The colony is branched in one plane and the end branches especially are flattened in the plane of branching. On large parts of the colony the coenenchyme is lacking; the calyces are low, dome-shaped.

The polyps have points with flattened spindles, up to 0.30 mm long ( Fig. 17 View FIGURE 17 a). A collaret is not present.

The surface layer of the branch has blunt ellipsoids and spindles, up to 0.35 mm long, with complex tubercles ( Fig 17 View FIGURE 17 b). Several of them with one side less tuberculate.

The lower layer has sclerites similar to those of the surface layer, but they are less tuberculate, and smaller, up to 0.25 mm long ( Fig. 17 View FIGURE 17 c).

Colour. Alive, the colony was pinkish in colour, preserved it is white. Sclerites are colourless.

Etymology. The species name is from the Latin planus, flat, referring to the flattened branches.

Remarks. Most Euplexaura species have rather small sclerites. Kükenthal (1924: 91–98) mentioned only four species with coenenchymal sclerites 0.25 mm long, or more: E. aruensis Kükenthal, 1911 , described from the Aru Islands, Indonesia, with sclerites up to 0.25 mm long; E. erecta Kükenthal, 1908 , from Japan, with sclerites up to 0.30 mm long; E. robusta Kükenthal, 1908 from Japan, with sclerites up to 0.32 mm long; E. kukenthali Broch, 1916 from NW Australia, with spindles up to 0.50 mm long. All these four species show no flattened branches and are therefore considered to be different species.

E. rhipidalis Studer, 1894 View in CoL , originally described from Singapore, does have flattened branches, and was recorded to occur in the nearby Red Sea ( Grasshoff 2000: 59). Grasshoff re-examined the type specimen of E. rhipidalis View in CoL and observed this species actually has sclerites with a wide range of size, up to 0.30 mm long, instead of the 0.15 mm long measured by Studer, and being close to the 0.35 mm reported for E. plana View in CoL .

Because of the similarities in colony shape and sclerite size between E. plana View in CoL and E. rhipidalis View in CoL , and because the drawings of sclerites presented by Grasshoff are rather schematic, we decided to make extra SEM photographs of RMNH Coel. 6040, a specimen identified by Stiasny (1959: 47) as Muricella tenera View in CoL , but synonymized with E. rhipidalis View in CoL by Grasshoff (2000). RMNH Coel. 6040 showed even longer blunt ellipsoids and spindles than recorded by Grasshoff for E. rhipidalis View in CoL , viz. up to 0.40 mm long ( Fig. 18 View FIGURE 18 c); like in E. plana View in CoL several of them with one side less tuberculate. However, the interior sclerites of RMNH Coel. 6040 ( Fig. 18 View FIGURE 18 d) are different from those of E. plana View in CoL ( Fig. 17 View FIGURE 17 c), they have less developed tubercles, and quite some sclerites have pointed ends. Strangely, sclerites like that were not at all depicted by Grasshoff. Because of the differently shaped interior sclerites, a character also present in the below described Euplexaura View in CoL spp. and the much more flattened branches than in E. rhipidalis View in CoL we decided to describe the present material as a new species.

RMNH

National Museum of Natural History, Naturalis

Kingdom

Animalia

Phylum

Cnidaria

Class

Anthozoa

Order

Alcyonacea

Family

Plexauridae

Genus

Euplexaura

Loc

Euplexaura plana

Namin, Samimi & Ofwegen, Van 2009
2009
Loc

E. rhipidalis

Studer 1894
1894
Loc

Euplexaura rhipidalis

Studer 1894
1894
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