Plicidentine in the oral fangs of parrotfish (Scarinae, Labriformes).

Parrotfish play important ecological roles in coral reef and seagrass communities across the globe. Their dentition is a fascinating object of study from an anatomical, functional and evolutionary point of view. Several species maintained non-interlocked dentition and browse on fleshy algae, while others evolved a characteristic beak-like structure made of a mass of coalesced teeth that they use to scrape or excavate food off hard limestone substrates. While parrotfish use their highly specialized marginal teeth to procure their food, they can also develop a series of large fangs that protrude from the upper jaw, and more rarely from the lower jaw. These peculiar fangs do not participate in the marginal dentition and their function remains unclear. Here we describe the morphology of these fangs and their developmental relationship to the rest of the oral dentition in the marbled parrotfish (Leptoscarus vaigiensis), the star-eye parrotfish (Calotomus carolinus), and the palenose parrotfish (Scarus psittacus). Through microtomographic and histological analyses, we show that some of these fangs display loosely folded plicidentine along their bases, a feature that has never been reported in parrotfish. Plicidentine is absent from the marginal teeth and is therefore exclusive to the fangs. Parrotfish fangs develop a particular type of simplexodont plicidentine with a pulpal infilling of alveolar bone at later stages of dental ontogeny. The occurrence of plicidentine and evidence of extensive tooth wear, and even breakage, lead us to conclude that the fangs undergo frequent mechanical stress, despite not being used to acquire food. This strong mechanical stress undergone by fangs could be linked either to forced contact with congeners or with the limestone substrate during feeding. Finally, we hypothesize that the presence of plicidentine in parrotfish is not derived from a labrid ancestor, but is probably a recently evolved trait in some parrotfish taxa, which may even have evolved convergently within this subfamily.

A DNA barcode reference library of French Polynesian shore fishes.

The emergence of DNA barcoding and metabarcoding opened new ways to study biological diversity, however, the completion of DNA barcode libraries is fundamental for such approaches to succeed. This dataset is a DNA barcode reference library (fragment of Cytochrome Oxydase I gene) for 2,190 specimens representing at least 540 species of shore fishes collected over 10 years at 154 sites across the four volcanic archipelagos of French Polynesia; the Austral, Gambier, Marquesas and Society Islands, a 5,000,000 km2 area. At present, 65% of the known shore fish species of these archipelagoes possess a DNA barcode associated with preserved, photographed, tissue sampled and cataloged specimens, and extensive collection locality data. This dataset represents one of the most comprehensive DNA barcoding efforts for a vertebrate fauna to date. Considering the challenges associated with the conservation of coral reef fishes and the difficulties of accurately identifying species using morphological characters, this publicly available library is expected to be helpful for both authorities and academics in various fields.

Pseudogramma polyacantha complex (Serranidae, tribe Grammistini): DNA barcoding results lead to the discovery of three cryptic species, including two new species from French Polynesia.

The Pseudogramma polyacantha species complex was found to harbor cryptic taxonomic diversity with three similar, but genetically divergent, species previously hidden in the complex. The true Pseudogramma polyacantha occurs from French Polynesia to South Africa and has modally 19 (many with 20) segmented dorsal-fin rays, modally 16 segmented anal-fin rays, a relatively short lateral line, no dermal flap or small tentacle dorsally on eye, and extensive scalation on the interorbital, suborbital and dentary. Pseudogramma brederi (previously synonymized with P. polyacantha) is recognized as a valid species occurring from Hawaii to Mauritius and having modally 21 segmented dorsal-fin rays, modally 17 segmented anal-fin rays, a relatively long lateral line, no dermal flap or small tentacle dorsally on eye, and relatively well-developed scalation on the interorbital, suborbital and dentary. Pseudogramma galzini n. sp. is described as a new species known only from French Polynesia and having modally 22 segmented dorsal-fin rays, modally 17 segmented anal-fin rays, a relatively long lateral line, no dermal flap or small tentacle dorsally on eye, and limited scalation on the interorbital, suborbital and dentary. Pseudogramma paucilepis n. sp. is described as a new species known only from French Polynesia and having 20 segmented dorsal-fin rays, modally 16 segmented anal-fin rays, a relatively long lateral line, no dermal flap or small tentacle dorsally on eye, and relatively reduced scalation on the interorbital, suborbital and dentary. A mtDNA COI analysis including all available Pseudogramma sequences shows well-supported genetic divergence between the two new species and among congeners.

Early life adversity increases foraging and information gathering in European starlings, Sturnus vulgaris.

Animals can insure themselves against the risk of starvation associated with unpredictable food availability by storing energy reserves or gathering information about alternative food sources. The former strategy carries costs in terms of mass-dependent predation risk, while the latter trades off against foraging for food; both trade-offs may be influenced by an individual's developmental history. Here, we consider a possible role of early developmental experience in inducing different mass regulation and foraging strategies in European starlings. We measured the body mass, body condition, foraging effort, food consumption and contrafreeloading (foraging for food hidden in sand when equivalent food is freely available) of adult birds (≥10 months old) that had previously undergone a subtle early life manipulation of food competition (cross-fostering into the highest or lowest ranks in the brood size hierarchy when 2-12 days of age). We found that developmentally disadvantaged birds were fatter in adulthood and differed in foraging behaviour compared with their advantaged siblings. Disadvantaged birds were hyperphagic compared with advantaged birds, but only following a period of food deprivation, and also spent more time contrafreeloading. Advantaged birds experienced a trade-off between foraging success and time spent contrafreeloading, whereas disadvantaged birds faced no such trade-off, owing to their greater foraging efficiency. Thus, developmentally disadvantaged birds appeared to retain a phenotypic memory of increased nestling food competition, employing both energy storage and information-gathering insurance strategies to a greater extent than their advantaged siblings. Our results suggest that subtle early life disadvantage in the form of psychosocial stress and/or food insecurity can leave a lasting legacy on foraging behaviour and mass regulation even in the absence of food insufficiency during development or adulthood.