兩種擬態枯葉的珊瑚礁魚類是否有類似的成長歷程？
 |
| 圓眼燕魚 (Platax orbicularis)，幼期 photo from Chaloklum diving |
 |
| 圓眼燕魚 (Platax orbicularis)，成體 photo from 圓眼燕魚 (wiki) |
摘要
Mimesis is a relatively widespread phenomenon among reef fish, but the ontogenetic processes relevant for mimetic associations in fish are still poorly understood. In the present study, the allometric growth of two allopatric leaf-mimetic species of ephippid fishes, Chaetodipterus faber from the Atlantic and Platax orbicularis from the Indo-Pacific, was analyzed using ten morphological variables. The development of fins was considered owing to the importance of these structures for mimetic behaviors during early life stages. Despite the anatomical and behavioral similarities in both juvenile and adult stages, C. faber and P. orbicularis showed distinct patterns of growth. The overall shape of C. faber transforms from a rounded-shape in mimetic juveniles to a lengthened profile in adults, while in P. orbicularis, juveniles present an oblong profile including dorsal and anal fins, with relative fin size diminishing while the overall profile grows rounder in adults. Although the two species are closely-related, the present results suggest that growth patterns in C. faber and P. orbicularis are different, and are probably independent events in ephippids that have resulted from similar selective processes.
 |
| 大西洋棘白鯧 (Chaetodipterus faber)，成體 photo from Kamila Sedziak/Marcin Smok |
如果兩個物種呈現類似生態性目的，雖然型態在成長的過程中發生變化，那麼擁有類似生態目的的物種的變化會不會相似呢？本篇所討論的大西洋棘白鯧 (Chaetodipterus faber)與圓眼燕魚 (Platax orbicularis)，幼體時的行為與型態被認為很像掉落在水面的葉子，成體則長的與幼體完全不像，型態發生很大的改變（這稱為異速生長, allometric growth）。這兩個種的親緣關係「似乎」很近，因此作者想瞭解這兩個擁有相似的成長過程的物種，型態變化的趨勢是不是也很像。
| photo from Fig. 1 大西洋棘白鯧 A) 擬態型幼體 B)非擬態型亞成體 C) 非擬態型成體 圓眼燕魚 D-E) 擬態型幼體 F) 非擬態型成體 |
 |
| photo from Fig. S1 相對物種與年齡表示如上圖 |
作者藉由比較各個不同的生長位置，透過形質測量的方式比較異速生長的相似性。結果發現雖然這兩種魚都有這個現象，但異速生長的相似度是顯著有差異，顯示這兩種魚的擬態與異速生長的演化來源可能是獨立的。
| photo from Fig. 3 CAP analysis，結果顯示兩種魚不同型態有差異 |
可是這兩種魚不同屬，說牠們是"closely-related species"沒問題嗎？
另外，兩種魚都有機會棲息在紅樹林區，說牠們像枯葉（中文wiki居然說擬態垃圾！？），圓眼燕魚也就算了，看起來是有個幾分像，可是那個白鯧你跟我說這像枯葉？
擬態這種事果然是見仁見智。
，幼期 photo from Chaloklum diving 圓眼燕魚 ( Platax orbicularis )，成體 photo from 圓眼燕魚 (wiki) 標題： Comparative...){kind=link}
0 comments