This article is a guest post by long term coral-taxonomy Liason Joseph Rowlett. His印度太平洋珊瑚书is one of the best and newest references to learn more about coral identification.
Coelastrea进入这个世界的陷入困境。该属的历史可追溯到杰出的Addison Emery Verrill的1866年论文，他在其中简要介绍了C. Tenuisbased on a single specimen collected from the “Sandwich Islands?”. These islands are better known to us today as Hawaii, but, alas, there is no coral in this region resembling Verrill’s specimen; in fact, just a single merulinid occurs there, the decidedly differentCyphastreaocellina。那么，tenuis呢？
Owing to the confusion surrounding this name,Coelastrea(pronounced seal-ASS-tree-uh) was largely ignored for much of its existence, more often than not being regarded as a synonym ofGoniastrea- 属的属在隔片的内边缘上有裂片，形成一个环绕着小柱的“冠”，一种将它们与类似的merulinid分开的特征，例如Favitesand帕拉蒂拉。
But this changed following a 2014 revision of the merulinids, wherein specimens ofGoniastrea AsperaandG. palauensiswere shown to be genetically closer toDipsastraea（一个包含印度太平洋物种的属Favia). Comparison of the type specimens ofC. TenuisandG. asperarevealed that the two likely represented the same species, and thusCoelastreawas resurrected from the dead, taxonomically speaking, though it remains difficult to diagnose in terms of morphology.
Likewise, there is considerable uncertainty regarding how diverse this group is. If we were to assume thatC. TenuisandC. Aspera确实是一个又一个，那么似乎只有两个成员。C. Aspera has been recognized as widespread in the Andaman-Pacific region (though it has also been questionably reported from the Western Indian Ocean), and it is by far the more commonly reported species, often occurring in abundance on intertidal reef flats.
其他物种，Coelastrea palauensis, is described from Palau and was originally classified withinFavia，由于类型的样品，具有弱分离的冠状石壁（即亚策略）。但是，由于该物种经常融合了冠状石壁（即谷物），因此后来被融入Favites。。。and since there is also a prominent crown of septal lobes surrounding the columella, it was ultimately reclassified as aGoniastrea, before finally settling into its current home inCoelastrea。Aquarists will be familiar with this coral as the ‘Prism Favia’ (or, rather, one of the Prism Favias, as this trade name is applied haphazardly to a variety of multi-colored merulinids).
The main morphological distinction with these species is size:C. Aspera具有平均直径4-8毫米的冠状石，远小于C. palauensis，其珊瑚岩可以达到2厘米以上。殖民地C. palauensis也小得多，很少有十几个息肉，而C. Asperaforms pillowy colonies with hundreds of polyps. Coloration may also diagnose these to some extent, as the ‘Prism Favia’ tends to have contrastingly colored oral discs and corallite walls, whileC. Aspera通常是棕色或斑驳的棕色。
But of course things are not so simple, dear reader. Reproductive differences have been noted in the population ofC. Aspera来自日本，最近在Mitsuki等人的一项研究中对此进行了研究。已经表明，一些菌落分别发出卵和精子，而其他菌落将鸡蛋和精子释放在一起，这两组在不同的时间产卵。lo和看，遗传数据证实这些确实是不同的物种，在整个西太平洋地区的同伴中发生。
从形态上讲，它们几乎是无法区分的，除了在隔膜上存在一些非常小的差异。检查类型标本C. Aspera，C。Tenuis, and several other purported synonyms (equisepta, mantonae, spectabilis, incrustans), led to the recognition of the long-forgottenC. incrustans作为捆绑果岭菌落的有效物种。
The Mitsuki study was exhaustive in their inquiry, utilizing breeding studies to confirm that cross-fertilization of these species is rarely successful. Their distributions are similar, buy slightly different, withC. Asperahaving a more limited range, ending abruptly at the Amami-Oshima Islands (thus not extending into the cooler reefs of mainland Japan), whereasC. incrustans出现在北至Wakayama，也出现在安达曼海，在这里C. Asperais apparently absent.
我们的老朋友Addison Emery Verrill描述了Goniastrea Aspera（实际上，它是在同一页面上发表的，在同一页面上描述了可能是特定的C. Tenuis),他设法创造混乱with the origins of this species as well. His description quite clearly states that the type locality was Hong Kong, but the specimens themselves bear labels indicating their provenance was “Loo Choo”, thus somewhere in or around Okinawa. Nice work, Addison.
And somehow this genus gets even more confusing! There’s genetic data suggesting the presence of another nearly indistinguishable species, with specimens found in Saudi Arabia, Thailand, and Japan—the single specimen examined from Japan had green oral discs, while the Arabian material has been tentatively identified as bothC. AsperaandC. palauensis, suggesting some level of phenotypic plasticity.
And there’s also some concern surrounding another species described by the loathsome Addison Emery Verrill; his FijianPrionastraea spectabilis对于Coelastrea中的任何事物都是不良比赛。而且，对Huang等人进行遗传测序的标本也很有可能被误认，质疑是否是否质疑C. palauensisis correctly classified—the material used in their study forC. AsperaandC. palauensisall originated from Singapore, where the ‘Prism Favia’ phenotype appears to be absent. And compounding all of this uncertainty is the reticence of morphologists
like Charles Veron, who brusquely dismisses the Huang et al revision, stating that “[Coelastrea] is a synonym of帕拉蒂拉”.
那么,这给我们吗?Coelastrea tenuisis probablyC. Aspera，不是C. incrustans， 或者C. palauensis, which may or may not be misclassified… plus there’s probably another species that needs to be recognized, and maybe alsoC. spectabilis。Merulinid分类法不适合胆小的人。不惜一切代价避免它。
