Molecular phylogenetic evidence supports a new family of octocorals and a new genus of Alcyoniidae (Octocorallia,Alcyonacea)

Molecular phylogenetic evidence indicates that the octocoral family Alcyoniidae is highly polyphyletic, with genera distributed across Octocorallia in more than 10 separate clades. Most alcyoniid taxa belong to the large and poorly resolved Holaxonia–Alcyoniina clade of octocorals, but members of at least four genera of Alcyoniidae fall outside of that group. As a first step towards revision of the family, we describe a new genus, Parasphaerasclera gen. n., and family, Parasphaerascleridae fam. n., of Alcyonacea to accommodate species of Eleutherobia Pütter, 1900 and Alcyonium Linnaeus, 1758 that have digitiform to digitate or lobate growth forms, completely lack sclerites in the polyps, and have radiates or spheroidal sclerites in the colony surface and interior. Parasphaerascleridae fam. n. constitutes a well-supported clade that is phylogenetically distinct from all other octocoral taxa. We also describe a new genus of Alcyoniidae, Sphaerasclera gen. n., for a species of Eleutherobia with a unique capitate growth form. Sphaerasclera gen. n. is a member of the Anthomastus–Corallium clade of octocorals, but is morphologically and genetically distinct from Anthomastus Verrill, 1878 and Paraminabea Williams & Alderslade, 1999, two similar but dimorphic genera of Alcyoniidae that are its sister taxa. In addition, we have re-assigned two species of Eleutherobia that have clavate to capitate growth forms, polyp sclerites arranged to form a collaret and points, and spindles in the colony interior to Alcyonium, a move that is supported by both morphological and molecular phylogenetic evidence.     

Shallow-water zoantharians (Cnidaria,Hexacorallia) from the Central Indo-Pacific

Despite the Central Indo-Pacific (CIP) and the Indonesian Archipelago being a well-known region of coral reef biodiversity, particularly in the ‘Coral Triangle’, little published information is available on its zoantharians (Cnidaria: Hexacorallia: Zoantharia). In order to provide a basis for future research on the Indo-Pacific zoantharian fauna and facilitate comparisons between more well-studied regions such as Japan and the Great Barrier Reef, this report deals with CIP zoantharian specimens in the Naturalis collection in Leiden, the Netherlands; 106 specimens were placed into 24 morpho-species and were supplemented with 88 in situ photographic records from Indonesia, the Philippines, and Papua New Guinea. At least nine morpho-species are likely to be undescribed species, indicating that the region needs more research in order to properly understand zoantharian diversity within the CIP. The Naturalis’ zoantharian specimens are listed by species, as well as all relevant collection information, and in situ images are provided to aid in future studies on zoantharians in the CIP.     

Species richness of resident and transient coral-dwelling fish responds differentially to regional diversity

Aim To determine whether the diversity of resident and transient coral‐dwelling fish responds differentially to gradients in regional species richness. Location Three regions in the Indo‐Pacific (Red Sea, western Indian Ocean, Great Barrier Reef) which contain increasingly larger regional diversities of reef fish. Methods I surveyed fish residing within branching coral species. Fish species were a priori categorized as resident or transient based on the degree of affiliation between the fish and live coral. To compare among regions that differ in coral diversity I used a modified species–volume relationship (SVR). Each point in the SVR represents the total number of fish species, resident or transient, found within the cumulative volume of a specific coral species. Empirical SVRs were further compared with random‐placement null models. Results For transient species, I found that the observed SVRs did not differ consistently from those expected from random samples drawn from the corresponding regional species pools. In addition, for a given volume of coral, more fish species were found in richer regions, indicating strong regional influences on local diversity. In contrast, resident richness was lower than that expected from random samples of the species pool, and richness in rich regions was reduced comparably more than in poor regions. The SVRs of resident species were similar among regions with different regional diversities. Main conclusion These results suggest that, within coral species, transient fish richness is mostly influenced by stochastic allocation of species from the regional pool. Conversely, richness of resident species within a coral species is limited, making it independent of regional diversity. Since higher regional diversity of resident fish was not accompanied by higher richness per coral species or by decreased niche breadth, higher regional diversity of resident fish species must be rooted in higher coral richness. Consequently, ecological interactions between functional groups (coral and fish) can be powerful drivers of regional biodiversity.     

A set of polymorphic dinucleotide and tetranucleotide microsatellite markers for the Indo-Pacific humpback dolphin (Sousa chinensis) and cross-amplification in other cetacean species

Eleven dinucleotide and five tetranucleotide polymorphic microsatellite loci were presented for the Indo-Pacific humpback dolphin Sousa chinensis, a species categorized as ‘data deficiency’ in the IUCN Red List. These markers were developed to allow future population studies, such as characterization of population structure and genetic diversity that are important for the species’ conservation. The number of alleles ranged from 2 to 9 with observed heterozygosity ranging from 0.167 to 0.917, and expected heterozygosity ranging from 0.159 to 0.913. Test of these loci in five additional cetacean species found that 10–13 loci have successful cross-amplifications.     

Sibling speciation by life-history divergence in Dendropoma (Gastropoda; Vermetidae)

Dendropoma meroclista has been found on six islands and one continental site between Hawaii and Kenya; it occurs in shallow-subtidal and low-intertidal habitats and has either no, or very limited, planktic development. A very similar form has been found only in the Indian Ocean (Sinai and Madagascar), where it forms gregarious masses on exposed intertidal ledges. This form also produces many more, smaller eggs than the described species and has a planktotrophic larva. While adult anatomies of the two forms are indistinguishable, the Sinai-Madagascar form has a smaller protoconch with distinctive sculpture. These apparent sibling species provide a case of speciation occurring by life-history divergence within a very conservative morphology and present a surprising example of wider distributional range in the species with little apparent capacity for dispersal.     

Pleistocene isolation and recent gene flow in Haliotis asinina, an Indo-Pacific vetigastropod with limited dispersal capacity

Haliotis asinina is a broadcast-spawning mollusc that inhabits Indo-Pacific coral reefs. This tropical abalone develops through a nonfeeding larval stage that is competent to settle on specific species of coralline algae after 3-4 days in the plankton. Failure to contact an inductive algae within 10 days of hatching usually results in death. These life cycle characteristics suggest a limited capacity for dispersal and thus gene flow. This makes H. asinina particularly suitable for elucidating phylogeographical structure throughout the Indo-Malay Archipelagoes, and eastern Indian and western Pacific Oceans, all regions of biogeographical complexity and high conservation value. We assayed 482 bp of the mitochondrial cytochrome oxidase II gene in 206 abalone collected from 16 geographically discrete sites across the Indian and Pacific Oceans and Indo-Malay Archipelagoes. DNA sequence variation was analysed via population genetics and phylogenetics, and by nested clade analyses (NCA). Our data resolved clear phylogeographical breaks among major biogeographical regions, with sequence divergences ranging from a high of 3.7% and 3.0% between Indian and Pacific sites and Pacific and Indo-Malay sites, respectively, to a low of 1.1% between Indian and Indo-Malay sites. Despite the apparent limited dispersal capacity of H. asinina, no finer scale phylogeographical structure was resolved within the respective biogeographical regions. However, amova and NCA identified several significant associations between haplotypes and geographical distribution, most notably higher gene flow among geographical populations associated with major ocean currents. Our study provides further evidence that larval dispersal capacity alone is not a good predictor of population genetic structure in marine invertebrates. We infer instead that a combination of historical events (long-term barriers followed by range expansion associated with Pleistocene sea level changes) and contemporary processes (gene flow restricted by life history and oceanography) have shaped observed patterns of H. asinina phylogeography.     

POPULATION ANALYSES OF INDO-PACIFIC HUMPBACK DOLPHINS SOUSA CHINENSIS IN ALGOA BAY,EASTERN CAPE,SOUTH AFRICA1

Mark-recapture analyses were performed on photo-identification data for Indo-Pacific humpback dolphins (Sousa chinensis) inhabiting Algoa Bay, on the Eastern Cape coast of South Africa. Boat-based photo-ID surveys were undertaken between May 1991 and May 1994. The rate of discovery of newly identified dolphins, distribution of sightings and frequency of resightings of known individuals indicate a high level of seasonal immigration of humpback dolphins into, and emigration from, the Algoa Bay region in summer. Consequently, humpback dolphins from Algoa Bay appear to be part of a substantially larger population that uses a considerable length of the coastal zone. The minimum population size is estimated to be about 466 dolphins.