Volume 18, Issue 3 – 15 July 2012
Volume 18, Issue 3 – 15 July 2012
Phillip C. Heemstra and K. V. Akhilesh : A review of the anthiine fish genus Pseudanthias (Perciformes: Serranidae) of the western Indian Ocean, with description of a new species and a key to the species, pp. 121-164
Nineteen species of the serranid fish genus Pseudanthias Bleeker are recognized in the western Indian Ocean (including the Red Sea and Persian Gulf): Pseudanthias bicolor, P. bimaculatus, P. bimarginatus, P. connelli, P. conspicuus, P. cooperi, P. evansi, P. gibbosus, P. heemstrai, P. hypselosoma, P. ignitus, P. lunulatus, P. marcia, P. pulcherrimus, P. squamipinnis, P. taeniatus, P. townsendi, P. unimarginatus and Pseudanthias pillai sp. nov. is described from the south-west coast of India. Pseudanthias gibbosus (Klunzinger) is resurrected from the synonymy of P. squamipinnis and is shown to have a precocious male morph. Discovery of three colour morphs for P. gibbosus is an example of the complicated reproductive systems of these species. Diagnoses, distributions, illustrations and a key to all the species of Pseudanthias in the western Indian Ocean are given.
Pseudanthias bicolor, 83 mm SL, male, Mauritius. Photo by J. E. Randall.
Leonardo de Oliveira Armesto and Natalie Villar Freret-Meurer: Testing for camouflage of the Brazilian seahorse Hippocampus reidi (Syngnathidae) using the territorial damselfish Stegastes fuscus (Cuvier) (Pomacentridae), pp. 165-170
Seahorses present many characteristics such as variable colour, skin fronds and sedentary behaviour that provide camouflage as a defense mechanism. This study aims to test seahorse camouflage effectiveness in relation to a territorial species. Seahorses were translocated into the territory of the damselfish Stegastes fuscus (Cuvier) and its aggressive behaviour was recorded. Stegastes fuscus was chosen as being a good model of an aggressive fish, probably able to detect any transgressor. Seahorse size, sex, colour and mobility were recorded, as was the colour of the substrate used as holdfast. Eighty-four percent of the translocated seahorses were not attacked. There was no relation between number of attacks and size, sex or colour of seahorse and its holdfast. Seahorses that remained still during the experiment (84%) were not attacked, but those that moved were attacked (16%). It was observed in this study that neither seahorse color nor size were relevant characters in camouflage fitness, but probably all these together, including behavior, improved survival fitness.
Hippocampus reidi in its natural habitat. Photo by N. V. Freret-Meurer.
Gerald R. Allen and Joshua A. Drew: A new species of Damselfish (Pomacentrus: Pomacentridae) from Fiji and Tonga, 171-180
Pomacentrus maafu is described from 195 specimens, 10.1-65.8 mm SL, collected at Fiji and Tonga. DNA analysis reveals it is the sister species to Pomacentrus moluccensis from the Western Pacific. The two species are indistinguishable on the basis of meristic and morphometric data, but are easily distinguished by colour pattern differences. The new species is mainly brown on the body with variable amounts of yellow on the head and adjacent anterior body, and it also has a yellow caudal fin and peduncle. In contrast, P. moluccensis is entirely bright yellow. Results of DNA analysis show that the two species are genetically distinct, with a divergence of 8.2% at the mitochondrial control region locus which is indicative of species-level differentiation among the Pomacentridae. The new species forms small aggregations around branching and tabular acroporid corals at depths of about 2-15 m.
Pomacentrus maafu, approximately 55 mm SL, underwater photograph at Viti Levu, Fiji. Photo by G. R. Allen.