多年来,我们看到了数百个不同的帕利斯和Zoas。同时,我们自信地称为Palythoa和其他Zoanthids。例如,我可以轻松地指出一个帕利亚(Palythoa)的grandis,并确定它实际上是一个帕利(Paly)。我敢打赌,农场!对于初学者来说,它具有巨大的绿色斑点息肉,看起来就像我在网上见过的每一个大型息肉一样。
同样,我在垫子中生长了各种微小的息肉。Zoanthids对吗?看着鹰眼Zoas的形象的人不会太多,除了Zoanthids之外,没有其他东西。
问题是,我看到的Zoanthids和Palythoa越多,我遇到的个人就越难以区分。例如,这里是息肉的图片,我会根据圆盘的形状和触角的外观称之为zoanthid:
但这是我也称之为Zoanthid的其他息肉的四倍:
他们都是Zoas吗?
到目前为止,我从未真正想过要使一个息肉成为帕利和另一个Zoa的原因。想一想,您将如何表达差异。
I would consider factors such as:
- The size of the polyp
- 触角的形状(它们是圆形的还是尖的?)
- 甚至不太科学的:它看起来像其他人所说的是在线图片是Paly还是Zoa。
不幸的是,这些问题没有优雅的答案。目前,这些珊瑚的分类学是一团糟。在1990年,有300多个不同的描述物种,但到1998年,该数字被缩减到大约60种普遍接受的物种。分类在很大程度上取决于研究人员观察到的珊瑚的标准。
What are the criteria for identification?
This raises the question, “Who gets to decide what the criteria are?” It’s never just one person. A general consensus is established after a process of extensive peer-review and healthy debate on the topic. That, in a nutshell, is why there is so much chaos when it comes to Zoanthid and Palythoa taxonomy. Corals, in general, do not receive nearly the same attention as other organisms get, so that process of scientific debate is limited.
However, while limited, it is far from non-existent. I encourage anyone interested in identification beyond made-up names to take a look at published scientific journals to get an appreciation of what really goes into coral taxonomy.
立即清楚的是,科学界对这些珊瑚的看法与我们的业余爱好者不同。虽然我们倾向于关注特定息肉的美学特征,例如颜色和图案,但研究人员着眼于其他特征,例如肠系膜的排列,线虫的形状和大小以及隔sapa的数量。根据研究人员决定关注的身体特征,可以到达截然不同的进化树。
Genetic testing
In addition to comparative morphology, genetic testing has become more popular as a method of identification. The advantage to using genetic testing is that there is a high degree of specificity compared to other methods. Still, genetic testing has its flaws. The evolutionary tree that genetic testing produces varies depending on which DNA or RNA sequences were analyzed.
For example, if you look at the human genome (which has been completely mapped out), you will find that it is very similar to that of other primates. How similar? Humans and chimps share over 90% of the same DNA. If random segments of DNA were tested over 90% of the time, these tests would indicate humans and chimps are the same species. That last 3 to 5% makes a big difference.
It gets even more complicated once you start considering epigenetics, which studies how much of a genome is expressed. It is entirely possible for genetically identical individuals to have a completely different physical appearance depending on the environment they grew up in.
以人类双胞胎的研究为例。尽管有相同的DNA,但在出生时分离并在以后团聚的相同的双胞胎看起来完全不同。环境在表达基因的角色中起着重要作用。
The same issue holds true for Zoanthids and Palythoa when it comes to genetic testing. It is hard to isolate a segment of DNA or RNA that has within it enough diversity to differentiate species. And NOBODY has a good understanding of which genes are being expressed in some Zoanthids or Palythoa and not in others despite having identical DNA.
Conclusion
Long story short, identification is hard. In fact, the whole subject of Zoa and Paly identification is chaotic at best. Keep this in mind the next time you meet someone who claims to know it all about Zoas and Palys (I bet you have already met them).