This is an open access article under the terms of the Creat ive Commo ns Attri bution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Intraspecific variability, although comparably less studied than interspecific variation, is an important tool in understanding population responses to environmental gradients. This study investigated intraspecific trait variation across three contrasting aquatic flow habitat types (intermittent creek, billabong and river) in a common mouth‐brooding freshwater fish in northern Australia, the mouth almighty Glossamia aprion. Samples of G. aprion were collected at various sites, within the Daly River catchment. It was predicted that a number of morphological and reproductive traits would vary among individuals across the contrasting habitats. Five out of the nine morphological and reproductive traits studied significantly varied across flow habitat types. Significant intraspecific variation in functional traits related to foraging and reproduction, such as relative eye size, eye vertical position and relative maxillary length in males suggest that the inherent characteristics of each flow habitat type could be exerting selective pressure on the morphology of G. aprion. Interestingly, traits related to swimming performance (body lateral shape) and manoeuvrability (pectoral fin ventral position) differed between flow habitat types but showed inconsistent responses to predictions. Whilst this study was temporally and spatially limited, it highlights that intraspecific variability in morphological traits can occur among flow habitat types over relatively small spatial scales.

While mouthbrooding is not an uncommon parental care strategy in fishes, paternal mouthbrooding only occurs in eight fish families and is little studied. The high cost of paternal mouthbrooding to the male implies a low risk of investment in another male's offspring but genetic parentage patterns are poorly known for paternal mouthbrooders. Here, we used single-nucleotide polymorphism genetic data to investigate parentage relationships of broods of two mouthbrooders of northern Australian rivers, mouth almighty Glossamia aprion and blue catfish Neoarius graeffei . For N. graeffei , we found that the parentage pattern was largely monogamous with the brooder male as the sire. For G. aprion , the parentage pattern was more heterogeneous including observations of monogamous broods with the brooder male as the sire (73%), polygyny (13%), cuckoldry (6%) and a brood genetically unrelated to the brooder male (6%). Findings demonstrate the potential for complex interrelationships of male care, paternity confidence and mating behaviour in mouthbrooding fishes.

Little is known about the reproductive biology of corals from the Philippines, despite this archipelago being at the center of coral reef biodiversity. Here, we report on the reproductive biology of a branching poritid species provisionally identified as Porites cf. cylindrica in the Bolinao‐Anda reef complex (BARC), northwestern Philippines. Histological examination and ex situ planulation observations reveal P.cf. cylindrica colonies to be gonochoric brooders that release actively swimming zooxanthellate larvae. Planulation appeared to occur throughout the year and there was significant lunar periodicity in planular release. The mean peak of release occurred from the 25th to 29th lunar day or just before the new moon, while peak in diel timing in planulation occurred during daytime between 08:00–11:00 h. Elsewhere in the Pacific, Porites cylindrica colonies are reported to broadcast spawn. If our species identification is correct, then this is the first report of brooding in P. cylindrica. Although there are no apparent morphological differences between the coral in this study and P. cylindrica reported from other sites, an alternative explanation for our findings is that our provisionally identified Porites cf. cylindrica is a different species. If so, our findings further highlight how difficulties with species identification in corals can influence our understanding of geographical variation in reproductive biology.