Paragoniastreavariabilis Kishi, Nomura & Fukami, sp. nov. (Cnidaria, Anthozoa, Scleractinia), a new coral species previously considered as a variant of Paragoniastreadeformis, from Japan and northern Taiwan

A new zooxanthellate scleractinian coral, Paragoniastreavariabilis Kishi, Nomura & Fukami, sp. nov. (Scleractinia, Merulinidae), is described from non-coral reef regions of Japan and northern Taiwan. This new species was previously recognized as a morphological variant of Paragoniastreadeformis (Veron, 1990) and can be morphologically distinguished from that species by lacking groove-and-tube structures on corallite wall joints, and by having larger calices, numerous septa, and up to three corallites in one valley. The new species also formed an independent clade from its congeners, P.australensis (Milne Edwards & Haime, 1857), P.deformis and P.russelli (Wells, 1954), in the molecular phylogeny based on the mitochondrial intergenic region and nuclear ribosomal internal transcribed spacers.

Integrating cryptic diversity into coral evolution, symbiosis and conservation

Understanding how diversity evolves and is maintained is critical to predicting the future trajectories of ecosystems under climate change; however, our understanding of these processes is limited in marine systems. Corals, which engineer reef ecosystems, are critically threatened by climate change, and global efforts are underway to conserve and restore populations as attempts to mitigate ocean warming continue. Recently, sequencing efforts have uncovered widespread undescribed coral diversity, including 'cryptic lineages'-genetically distinct but morphologically similar coral taxa. Such cryptic lineages have been identified in at least 24 coral genera spanning the anthozoan phylogeny and across ocean basins. These cryptic lineages co-occur in many reef systems, but their distributions often differ among habitats. Research suggests that cryptic lineages are ecologically specialized and several examples demonstrate differences in thermal tolerance, highlighting the critical implications of this diversity for predicting coral responses to future warming. Here, we draw attention to recent discoveries, discuss how cryptic diversity affects the study of coral adaptation and acclimation to future environments, explore how it shapes symbiotic partnerships, and highlight challenges and opportunities for conservation and restoration efforts.