Currently, between one-third and two-thirds of marine species may be undescribed, and previous estimates of there being well over one million marine species appear highly unlikely. More species than ever before are being described annually by an increasing number of authors. If the current trend continues, most species will be discovered this century.

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The stomatopods, or mantis shrimps, are malacostracan crustaceans of the subclass Hoplocarida. Extant hoplocarids belong to the order Stomatopoda and suborder Unipeltata, comprising the extinct, stem-lineage pseudosculdids and sculdids, and the crown group. Cladistic analysis including most or all genera of the unipeltatan families, and rooted to the extinct Tyrannophontidae, resulted in four most-parsimonious cladograms. The present results are more highly resolved and more robust than previous studies as the result of: more precise identification of suitable outgroups; a more complete outgroup data set, lessening the impact of missing data; and increased taxonomic sampling. The results largely support the existing five-superfamily classification, but as with two recent cladistic studies, Gonodactyloidea was polyphyletic. Gonodactyloidea is the basal crown-group superfamily and comprises mostly ‘smashers’. Two clades of ‘spearers’, Eurysquillidae and Parasquillidae, previously considered gonodactyloids, are more closely related to the Squilloidea and are referred to new superfamilies. The familial classification within Lysiosquilloidea is modified. Rather than deriving the ‘smashers’ from a long line of ‘spearers’, the present analysis suggests that the Unipeltata diverged in two broad directions from the outset. Hence, the gonodactyloid ‘smashers’ became specialised for hard substrates, and the remainder diversified into the other modern superfamilies, evolving more efficient ‘spearing’ claws, and occupying soft substrates.

Aim: After environmental disasters, species with large population losses may need urgent protection to prevent extinction and support recovery. Following the 2019-2020 Australian megafires, we estimated population losses and recovery in fire-affected fauna, to inform conservation status assessments and management.Location: Temperate and subtropical Australia. Time period: 2019-2030 and beyond.Major taxa: Australian terrestrial and freshwater vertebrates; one invertebrate group. Methods:From > 1,050 fire-affected taxa, we selected 173 whose distributions substantially overlapped the fire extent. We estimated the proportion of each taxon's distribution affected by fires, using fire severity and aquatic impact mapping, and new distribution mapping. Using expert elicitation informed by evidence of responses to previous wildfires, we estimated local population responses to fires of varying severity. We combined the spatial and elicitation data to estimate overall population loss and recovery trajectories, and thus indicate potential eligibility for listing as threatened, or uplisting, under Australian legislation. Results:We estimate that the 2019-2020 Australian megafires caused, or contributed to, population declines that make 70-82 taxa eligible for listing as threatened;

The crustacean order Stomatopoda comprises seven superfamilies of mantis shrimps, found in coastal waters of the tropics and subtropics. These marine carnivores bear notable raptorial appendages for smashing or spearing prey. We investigated the evolutionary relationships among stomatopods using phylogenetic analyses of three mitochondrial and two nuclear markers. Our analyses recovered the superfamily Gonodactyloidea as polyphyletic, with Hemisquilla as the sister group to all other extant stomatopods. A relaxed molecular clock, calibrated by seven fossil-based age constraints, was used to date the origin and major diversification events of stomatopods. Our estimates suggest that crown-group stomatopods (Unipeltata) diverged from their closest crustacean relatives about 340 Ma (95% CRI [401-313 Ma]). We found that the specialized smashing appendage arose after the spearing appendage ∼126 Ma (95% CRI ). Ancestral state reconstructions revealed that the most recent common ancestor of extant stomatopods had eyes with six midband rows of hexagonal ommatidia. Hexagonal ommatidia are interpreted as plesiomorphic in stomatopods, and this is consistent with the malacostracan ground-plan. Our study provides insight into the evolutionary timescale and systematics of Stomatopoda, although further work is required to resolve with confidence the phylogenetic relationships among its superfamilies.

The ¢rst demonstration, to our knowledge, of an evolutionary shift in communication mode in animals is presented. Some species of Ovalipes display spectacular iridescence resulting from multilayer re£ectors in the cuticle. This re£ector is unique in animals because each layer is corrugated and slightly out of phase with adjacent layers. Solid layers are separated from £uid layers in the re£ector by side branches acting as support struts. An e¡ect of this re£ector is that blue light is re£ected over a`broad' angle around a plane parallel to the sea £oor when the host crab is resting. Species of Ovalipes all possess stridulatory structures. The shallow-water species with the best developed stridulatory structures are non-iridescent and use sound as a signal. Deep-water species possess poorly developed stridulatory structures and display iridescence from most regions of the body. In deep water, where incident light is blue, light display is highly directional in contrast to sound produced via stridulation. Sound and light display probably perform the same function of sexual signalling in Ovalipes, although the directional signal is less likely to attract predators. Deep-water species of Ovalipes appear to have evolved towards using light in conspeci¢c signalling. This change from using sound to using light re£ects the change in habitat light properties, perhaps the hunting mechanisms of cohabitees, and its progression is an indicator of phylogeny. The changes in sexual signalling mechanisms, following spatial^geographical isolation, may have promoted speciation in Ovalipes.