A: C. ellenae, from Raja Ampats B: C. maurinae, from Cenderawasih Bay C: C. oxycephala, from Bali & Palawan Credit: Allen et al 2015
Earlier this year I wrote a review for a popular group of damselfishes—the Chrsyiptera hemicyanea complex—that show a complicated pattern of regional speciation. At the time, several of these biogeographical variants remained scientifically undescribed, but a new study by Gerry Allen and coauthors has addressed this gap in our knowledge, describing three new species in an important paper on the region’s population genetics. When combined with previous work in this field, a clearer picture is now developing of the processes that dictate the immense diversity surrounding the island of New Guinea.
D: C. cf oxycephala “genovariant” from Lembeh E: C. papuensis, from Milne Bay F: C. sinclairi, from Manus Island & Hermit Islands Credit: Allen et al 2015
For aquarists, Chrysiptera oxycephala is a relatively unfamiliar and unpopular species, with adults suffering from a relatively drab mix of dingy yellow and brown. Juveniles, on the other hand, are vibrant blue and yellow fishes which show their allegiance more clearly to the other colorful members of their species group—familiar offerings like the Yellowtail, Azure and Springer’s Damselfishes. However, juveniles from different locations of the Coral Triangle were noted to differ in the configuration of their patterning, often moreso than in the adults, which ultimately led these researchers to search for overlooked species diversity.
Credit: Allen et al 2015
Previous biogeographical studies of the Coral Triangle have strongly hinted at a major region of endemism centered on the island of New Guinea, which also includes the Solomon Islands in the east and the Muluku Islands to the West. The present study of C. oxycephala adds even more detail to this, as these newly recognized taxa are all exclusively endemic within this Melanesian ecoregion. While many other reef fishes from here—for instance, Chaetodontoplus poliourus or Amphiprion percula—can be found as seemingly homogenous populations spanning this entire region, these new damselfishes break down into multiple geographically restricted subpopulations now treated as distinct taxa. The maps and photographs included here give a brief account of the findings from Allen et al, which is expounded upon in far more detail in their paper. Overall, morphological differences between these taxa are minimal. C. maurinae, described from Cenderawasih Bay, is said to have (on average) one extra lateral line scale, as does an undescribed variant of C.… More:
The post Newly described damselfishes expand our understanding of Coral Triangle speciation appeared first on Reefs.com.