In light of our recent trend in picking apart cryptic species within a given complex like we did forPseudanthias pascalusandNemateleotris helfrichi, we continue yet again with a rather massive undertaking. This time withPseudanthias ventralis. This beautiful species is wide ranging across much of Oceania, but seems prone to insular variations with at least three major and rather distinct representations that can be grouped based on coloration as well as geographical range. The fluidity of its forms suggests its susceptibility to speciation, with one isolated populace in Hawaii already awarded full taxonomic upgrade. It isPseudanthias hawaiiensis.
当然,重要的是要注意,this article is not in anyway a scientific standard for splitting a species, but rather a suggestive piece based on comparison and analysis of various forms within the complex. In the range map above forP. ventralisyou can see that it has been roughly divided into a cross section of four, with major distinctive groups being found in four quadrants. These are the Southern Pacific and French Polynesian island chains, the Australian region encompassing New Caledonia and the Coral Sea, the Marshall Islands and Japan with Mariana as an intermediate, and finally Hawaii; where speciation has already awarded the area with the endemicP. hawaiiensis.
Cook Islands, Southern Pacific, French Polynesia and the Pitcairn Islands
The type locality ofPseudanthias ventralis是皮特凯恩群岛（Pitcairn Islands）的甘奈特山脊。因此，这里和周围地区的形式应正确描述物种的实际表示。我们将根据上述地图的象限以顺时针方式探索这些以及其他形式，并尝试在各种形式之间挑选任何表型或形态学差异。
上面的拼贴画描绘了南太平洋和法尼西亚山脉的第一个象限的各种标本。在其中，它还包括库克群岛和皮特凯恩岛集团。视为该物种的类型位置来自这里，应将其视为基准类型，以及以下所有其他区域形式应仔细比较这些形式。
InP. ventralis, the males are steely purple overall with the head encapsulated in yellow. The dorsum just beneath the dorsal fin is yellow washed, but is peppered so heavily in purple spots that in some extreme cases, the underlying yellow is obliterated completely. These purple spots tend to remain circular and distinct, which is an important characteristic when comparing with specimens in other locales. The dorsal fin is red only on the anterior spiny portion (clear in dead, preserved specimens), and hyaline or yellow tinted on the soft portion. The leading edge of the soft dorsal fin is also unmarked with no purple lines. Caudal fin is largely clear and unmarked, except for a pair of vertical purple lines. The anal fin is clear, but has a strong purple line delimiting a more deeply colored region corresponding to the anal spines and first rays which form the elongate leading edge of the fin.
雌性具有相同的紫色地面颜色，但没有标记，除了黄色的背鳍，在尾部的花梗中倾斜地结束后，它蔓延到背面的一条片。一条红色的拱形条纹将两种颜色分开，在背侧的后部附近。女性缺乏次要色素，例如雄性所拥有的紫色斑点。
珊瑚海，瓦努阿图和新喀里多尼亚
Moving west to the Coral Sea and New Caledonian region including Vanuatu, we find a completely different looking regional form ofP. ventralis. The males here differ primarily in their dorsal fin and tail coloration, as well as having a more reticulated spot pattern along the body just beneath the dorsal fin. The females are largely similar to those found in the type species. We will take a closer look as well as identify more clearly the differences below.
In this region, the males are also steely purple in basal colour, with the head encapsulated in yellow. The dorsum is also yellow washed, but contains a series of super imposed purple spots that conjoin to form a reticulated pattern travelling horizontally. In addition to that, a secondary set of yellow blotches and squiggles sit just beneath the purple reticulations. There are therefore two sets of body coloration here; a series of purple reticulated spotting on the yellow base of the dorsum, and a second set of yellow squiggles on the purple body coloration just beneath. The yellow squiggles is prominent enough such that it gives an impression of a separate line coming out of the head region and starting just behind the operculum.
The dorsal fin takes on the reverse coloration as the type species, with the anterior spinuous portion coloured in yellow while the soft rays in red. The red coloration in the soft rays is only limited however to the anterodorsal region, and does not creep to the posteroventral base, where it is coloured yellow. This is delineated by a diagonal line originating from the purple spotting on the dorsum, which extends to the tip of the fin.
The caudal fin also differs by having a weak red blotch or bar near the edge, with purple lines along its margin which always fails to encircle it. Like the type species, the anal fins are clear, but has a strong purple line delimiting a more deeply colored region corresponding to the anal spines and first rays which form the elongate leading edge of the fin.
女性几乎与具有相同黄色背鳍和红色拱形条纹的类型物种相同，将两种颜色分隔在尾花梗附近。
The Vanuatuan specimens are identical in appearance to the Coral Sea specimens, and in the photo above, the delimiting purple line on the dorsal fin can be more clearly seen. The red anterodorsal region is separated clearly by the yellow posteroventral base of the dorsal fin by this purple line which may or may not originate from the purple spotting on the body. However this line is always present one way or another in this regional form.
The photo above also more clearly demonstrates the purple spotting that can be seen here joining up into an irregular chain or reticulated pattern, very unlike the individual spots that pepper the type species in the Southern Pacific and French Polynesia. The secondary yellow squiggle that sits just beneath can also be observed.
The New Caledonian forms are basically identical to those from the Coral Sea and Vanuatuan region. Seeing as they all sit within the same biogeographical area, it is unlikely that variations would be alarmingly vicariant. The New Caldonian forms however do appear to be slightly more erythric and richer in coloration, but it is unknown if this characteristic is from the fish itself or from camera settings in the photographs taken.
The reticulated patterns on the dorsum do however appear to spread a little more extensively ventrally, but overall they do bear the same characteristics as the Coral Sea and Vanuatuan forms. The tail is also weakly spotted in red and the purple lines always fail to encircle it.
Japan, Marianas and the Marshall Islands
Moving northwards from the Coral Sea, Vanuatu and New Caledonian region, a different complex ofP. ventralis能够被找到的。这个象限包括在马歇尔和玛丽安娜群岛以及日本中发现的个体，该物种处于其范围内最限制。这里的形式比前面的地区中的形式更可变，并且显示了广泛的中间体，尤其是在尾鳍上的模式中。
The basal coloration of the males are as usual, steely purple with the head encapsulated in yellow. The dorsum is yellow washed as usual, and the purple spotting here are numerous, but small and never joined like the New Caledonian and Coral Sea forms. The specimens from this geographical area also lack the development of the secondary yellow squiggles found below the dorsum, and even if, it is usually highly vestigial and under developed.
背鳍完全是橙色或红色的，始终是黄色的后柔软部分。在这个综合体中，没有对角紫色线条在鳍上划定两种颜色。该组最独特的特征是尾鳍上高度发达的红色斑点，该尾鳍都存在于所有雄性标本中。在许多情况下，尾腔斑点几乎是完全圆形的，其包围从边界的紫色线条变化。实际上，找到带有紫色线条完全限制的尾部斑点的标本并不罕见。该组的另一个独特特征是肛门鳍上缺少任何划界线，完全是黄色的。
The males from this region have by far the most under developed dorsum markings, lacking the intricate reticulations that the other forms possess. They however are very unique in the caudal and anal fin characteristics, which is very much different from the other forms. The three photo collages from Ogasawara, Saipan and the Marshall Islands show some variability amongst individuals, especially in the development of the caudal blotch.
However the specimens are consistent enough to warrant placement in the same biogeographical range, possibly belonging in the same complex.
The females from this region are also different, and lack the distinctive red arching stripe that separates the yellow dorsum from the purple body. In most individuals, the stripe is entirely absent, or if rarely, found only as a thread.
菲律宾，斐济和帕劳（？）
In our search, we’ve been unable to find any information or photos pertaining to this species’ existence in Fiji and Palau. Fiji sits in the middle of the Coral Sea and the Cook Islands, so it is not unlikely that the species can be found there as well. However if the absence ofP. ventralisin Fiji is indeed certain, then it serves as a disjunct range between the Coral Sea individuals and those of the Cooks. This isolation could further support the speciation of the Coral Sea and New Caledonian forms.
Its absence from Palau is also curious, being one of the Oceanic islands situated so close to Saipan and the Marshalls. Perhaps the lack of photos and information is due to it being exceedingly rare in the area, or perhaps it is totally absent there. Why or whether or not this is true, we are not sure.
P. ventraliscan also be quite dubiously found in the Northern Philippines, where again it appears to be very rare. We’ve only managed to find a single photo of an aquarium specimen that arrived from a Philippine import. Being so close Japan, it is not unlikely thatP. ventraliscan be found there. The supposed Philippines individual above shares the same overall characteristics as the Japanese forms, and if anything it probably belongs in the same complex.
夏威夷and Johnston Atoll
The Hawaiian and Johnston Islands are home to a multitude of endemic species, one of which was a previously isolated form ofPseudanthias ventralisthat has now attained full taxonomic upgrade. The fish, once considered as a subspecies ofP. ventralis, is now recognised asPseudanthias hawaiiensis.P. hawaiiensisdiffers markedly fromP. ventralis, with the basal coloration drifting away from the usual purple, to take on a rich burnt orange. The posterior third of the body fading toward the caudal peduncle is a light lilac. The purple spotting that is so characteristic ofP. ventralis在男性中仅减少到只有一部分，在某些情况下完全不存在。
Interestingly,P. hawaiiensisalso differs morphologically, being much larger and with extremely long ventral fins; much longer than its sister species. These can often reach well pass the anal fins. The females, pictured below, is uniformly yellow, but in some individuals and perhaps under different lighting, the usual purple ventral portion of the body can be seen. Other than that, it is very much distinctive and different from the usual females ofP. ventralis.
Table of comparison
Although this article is derivative and observational, but based on distribution as well as color variation, it is not unlikely thatPseudanthias ventralishouses more than one species in its complex. The Coral Sea and New Caledonian specimens seem highly likely to form a distinctive sister group, and more studies or examination should be done on those specimens.
As far as fluidity in appearance goes, it seems that the males differ rather greatly from area to area, while the females remain relatively similar. The exception being those found in Japan, Marianas and the Marshall Is, where the females lack the red arching stripe that separates the yellow dorsum from its purple body. Males differ primarily in their dorsal and caudal fin markings, as well as the intensity and arrangement of the purple spotting on the dorum. In the New Caledonian and Coral Sea specimens, the spotting is not only highly conjoined and reticulated, but an additional set of yellow squiggles are present just beneath.
P. hawaiiensis是一个经典且非常好的例子，是同种异体形成的，其中一种新的且完全不同的物种从原始的谱系中演变出来。其中一些完全有可能P. ventralisforms we’ve discussed today have begun speciating away from the original type, and further analysis may one day warrant the elevation of these variants to full species level.
大感谢乔罗莱特,highly instrumental in the crafting of this article. The distribution maps as well as the coherence of this piece should be credited to him as well.
