Hamish Gordon Spencer

The coastal North Pacific kelp ecosystems are highly productive, supporting a rich faunal assemblage. Some historical aspects of this ecosystem remain poorly studied, as exemplified by the extinct Spectacled Cormorant Urile perspicillatus , whose Late Holocene distribution was apparently restricted to Bering Island. This cormorant’s taxonomic relationships remain unresolved and little is known about its ecology. We use ancient-DNA to reconstruct the evolutionary history of the Spectacled Cormorant. Mitogenomes from five of the six known historical skins form a strongly supported clade within Urile cormorants. The ancestors of Spectacled Cormorant diverged from its closest relatives, the Pelagic ( U. pelagicus ) and Red-faced ( U. urile ) cormorants, ∼6.98 Mya, and the population subsequently underwent a pronounced bottleneck. This divergence time is co-incident with the establishment of coastal kelp-forests. The Spectacled Cormorant may have been an integral part of the kelp-associated fauna as a large benthic-foraging predator. Similar to the sympatric Steller’s sea cow ( Hydrodamalis gigas ), the historical relict distribution of the Spectacled Cormorant may be the result of trophic collapse of kelp-forest ecosystems and subsistence hunting. Future palaeogenomic and dietary isotopic research, and reassessment of North Pacific archaeological and fossil assemblages, should shed light on the evolution and palaeoecology of this enigmatic seabird.

Problem: Rafting is now recognised as a key process influencing the distribution and connectivity of several marine and coastal species. Rafting scenarios are, however, often invoked in ways that do not account for clear differences in biogeographic outcomes. Here, we illustrate the value of utilising multiple lines of evidence (e.g. different life histories, ecologies, and dispersal frequencies) in elucidating the historical, modern, and future significance of ocean rafting. We discuss these issues using a range of exemplar studies from the Southern Ocean, where rafting clearly underlies many different distributional patterns, although our conclusions hold generally.Explanations: Such differences appear to be underpinned by variations in several life‐history characters, with, for instance, direct‐developing taxa more suited to long‐distance rafting events that might span multiple generations. Rafting success is also shaped by a diverse suite of factors including the durability of the raft, the presence/absence of resources and competitors (intra‐ or inter‐specific) at the destination, species' environmental tolerances, latitudinal movements in the position of oceanographic fronts, and the frequency and intensity of extreme events such as storms. Several of these factors are influenced by climate change, so a detailed understanding of their roles is increasingly important—particularly as many species' distributions are shifting.Future Prospects: The Southern Hemisphere—which has considerably more ocean than the Northern Hemisphere (81% vs. 61%)—provides biogeographers with a wealth of information on such processes, as well as intriguing examples of the puzzles we still face. Powerful new tools, including high‐resolution genomic analyses, ancient DNA, and environmental, ecological and oceanographic modelling, are providing a more granular picture of biogeographical patterns. These novel methods, together with a broader consideration of the factors affecting rafting success, can pave the way for an improved and properly integrated understanding of the eco‐evolutionary outcomes of long‐distance dispersal via rafting.

Although allelic variation is ubiquitous in natural populations, our theoretical models are poor at predicting the existence and properties of these observed polymorphisms. In this study, inspired by Van Valen's Red Queen hypothesis, we modeled the effect of viability selection in a deteriorating environment on the properties of allelic variation in populations subject to recurrent mutation. In Monte Carlo simulations, we found that levels of polymorphism consistently built up over time. We censused the simulated populations after 10,000 generations of mutation and selection, revealing that, compared with models assuming a constant environment, the mean number of alleles was greater, as was the range of allele numbers. These results were qualitatively robust to the addition of genetic drift and to the relaxation of the assumption that the viabilities of phenogenotypes containing a new mutation are independent of each other (i.e. incorporating a model of generalized dominance). The broad range of allele numbers realized in the simulated populations—from monomorphisms to highly polymorphic populations—more closely corresponds to the observed range from numerous surveys of natural populations than previously found in theoretical studies. This match suggests that, contrary to the views of some writers, selection may actively maintain genetic variation in natural populations, particularly if the selective environment is gradually becoming harsher. Our simulations also generated many populations with heterozygote advantage, a mismatch with real data that implies that this selective property must arise extremely rarely in natural populations.

The aptly named microcormorants (currently placed in the genus Microcarbo) form a morphologically diminutive and distinct clade sister to all other living cormorants and shags. However, the relationships within Microcarbo are largely speculative. Sequence data resolve these relationships unambiguously, with our phylogeny suggesting that the microcormorants separated from the other cormorants ~16 Mya and showing that the two African species [the reed (or long-tailed) cormorant, Microcarbo africanus, and the crowned cormorant, Microcarbo coronatus] are closely related sister taxa, forming a clade that diverged from the other microcormorants ~12 Mya. The deep split between the African microcormorants and the others is considerably older than many well-recognized generic splits within the cormorants (e.g. Leucocarbo and Phalacrocorax). Thus, we suggest that the African microcormorants warrant their own genus, and we erect Afrocarbo, with type species Pelecanus africanus. Within the reduced Microcarbo, we estimate that the little pied cormorant (Microcarbo melanoleucos of Australasia) separated from the sister pair of the Javanese and pygmy cormorants (respectively, Microcarbo niger from south/southeast Asia and Microcarbo pygmaeus from Europe) ~9 Mya and that the latter two species split ~2 Mya. Given the age of these splits, the microcormorants appear to represent another example of morphological conservatism in the Suliformes.

An endolithic lifestyle in mineralized substrates has evolved multiple times in various phyla including Bryozoa. The family Penetrantiidae includes one genus with ten extant and two fossil species. They predominantly colonize the shells of molluscs and establish colonies by chemical dissolution of calcium carbonate. Based on several morphological characters, they were described to be either cheilostome or ctenostome bryozoans. For more than 40 years, neither the characters of species identity and systematics nor the problem of their phylogeny was approached. Consequently, the aim of this study is to reevaluate species identities and the systematic position of the genus Penetrantia by analyzing at least six different species from eight regions with the aid of modern methods such as confocal laser scanning microscopy and 3D-reconstruction techniques. This study demonstrates that the musculature associated with the operculum and brood chamber shows significant differences from the cheilostome counterparts and seems to have evolved independently. Together with the presence of other ctenostome-like features such as true polymorphic stolons and uncalcified body wall, this finding supports a ctenostome affinity. Operculum morphology reveals many new species-specific characters, which, together with information about gonozooid morphology, tentacle number, and zooid size ranges, will enhance species identification. It also revealed a probable new species in Japan as well as potential cryptic species in France and New Zealand. In addition, this study increases the known distribution range of the family and its substrate diversity. Altogether, the new information collated here provides the basis for future work on a neglected taxon.

We report recent sightings, substantiated by color photographs and a short video, of a bilateral gynandromoph of the Green Honeycreeper (Chlorophanes spiza) from Villamaría, in the department of Caldas, Colombia. The bird exhibited typical male plumage on its right side and female plumage on the left. It was present for at least 21 months, and its behavior largely matched that of other wild Green Honeycreepers, although it often waited until they were gone before feeding on fruit that was put out daily by the property owners. We provide a comprehensive list and review of previous records of passerine bilateral gynandromorphy, noting which sex’s plumage occurred on the left side. We observe that female plumage is possible on either side, supporting the double-fertilization model of bilateral gynandromorphy.

The dorsal shell surface of the New Zealand-endemic chitonid Onithochiton neglectus exhibits ocelli (eyes) associated with sensory organs (aesthetes) penetrating the shell. Each ocellus includes a mineral lens which focusses light onto a retina, potentially able to resolve images. In order to discover the spatial resolution of lenses of O. neglectus, we isolated them, examined their mineralogy with X-ray diffractometry, imaged the constituent crystals with scanning electron microscopy, and mounted them onto a camera to directly observe and record images. Lenses of O. neglectus are aragonitic and therefore birefringent, providing two different focal lengths, possibly one for in-air and one for underwater vision. Chitons may be able to image nearby shapes with visual acuity equivalent to 6/24 (m), a VA_dec of 0.25. Onithochiton neglectus lenses can focus images in air about as well as a person with low visual acuity, sufficient to discern shapes and shadows in the surrounding environment. Lenses from subtidal O. neglectus were less eroded than those from intertidal environments; chitons in different habitats exhibit different visual acuity. It is unclear why a few lineages of chitons have developed such complex eyes; we speculate that body-orientation and navigation could be among the advantages driving such development.