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)

Because of the problematical identity and status of the type of the xeniid soft coral genus Cespitularia Milne-Edwards & Haime, 1850, the species C. stolonifera Gohar, 1938 is revised. Examination of the type colonies has led to the establishment of the new genus Unomia gen. n. which is described and depicted. This genus features a stalk, commonly divided into branches featuring a diffuse polypiferous part consisting of distal clustered polyps and proximal individual ones on the stalk or the basal membranous part of the colonies. The sclerites are ellipsoid platelets composed of dendritic calcite rods whose tips are distinct on the surface of the platelets. Freshly collected material from Venezuelan reefs where the species is invasive was subjected to molecular phylogenetic analysis, the results of which substantiate the taxonomic assignment of the new genus under U. stolonifera comb. n. A new species, U. complanatis, from Japan and Green Island (Taiwan) is described and further illustrates the extent of the interspecific morphological variation within the genus. The results reveal that the biogeographic distribution of Unomia gen. n. includes Pacific Ocean reefs in addition to the invaded Caribbean reefs.

由于1850年米尔恩 - 爱德华兹和海梅所描述的异花软珊瑚属（Cespitularia）的种类鉴定和分类地位存在问题，1938年戈哈尔所描述的匍匐异花软珊瑚（C. stolonifera）这一物种得到了修订。对模式群体的研究导致了新属——单花软珊瑚属（Unomia gen. n.）的建立，该属得到了描述和绘图展示。这个属具有一个茎，通常分为若干分支，其特征是具有一个弥散的水螅体部分，该部分由茎或群体基部膜质部分远端成簇的水螅体和近端单个的水螅体组成。骨针为椭圆形板状，由树枝状方解石杆组成，其尖端在板状表面清晰可见。从该物种入侵的委内瑞拉珊瑚礁新采集的材料进行了分子系统发育分析，分析结果证实了新属下单花软珊瑚（U. stolonifera comb. n.）的分类归属。来自日本和绿岛（台湾）的一个新物种——扁平单花软珊瑚（U. complanatis）得到了描述，进一步说明了该属内种间形态变异的程度。研究结果显示，单花软珊瑚属（Unomia gen. n.）的生物地理分布除了包括被入侵的加勒比海珊瑚礁外，还包括太平洋的珊瑚礁。