The limpet Patella aspera Röding, 1798, is a native species from the Macaronesian region whose fishing is regulated. The early life of limpets, including the settlement process, is poorly known thus far. The current study evaluated different substrates to induce settlement in P. aspera, including microalgae strains (Halamphora coffeaeformis, Navicula incerta and Pavlova sp.) and crustose coralline algae (CCA) obtained from limpet shells. The results showed that gametes obtained by dissection and matured artificially using alkalinized seawater baths can produce viable larvae able to metamorphose to juveniles. Feeding was not required during larval development, suggesting lecithotrophy. Early postlarvae were identified by the shedding of the velum, and juveniles were identified by teleoconch and active grazing behaviour. The presence of CCA shortened the timing for settlement and increased the ratio of juveniles. The type and abundance of CCA can influence settlement success. Moreover, the results suggested that settlement and metamorphosis in true limpets (Patellogastropoda) might be triggered by a two-step mechanism, i.e. a first cue influencing the shift between swimming and crawling activity and a second cue determining settlement and metamorphosis to early postlarvae and juveniles.

The complete larval development of the spider crab Maguimithrax spinosissimus (Lamarck, 1818) is re-described and illustrated in detail from laboratory-reared material. The development consisted of the typical pattern reported for the Majoidea, two zoeal stages and one megalopa. The complete larval development from hatching to first crab lasted 5–6 days at temperatures that ranged between 24–28 °C. Both zoeal stages of M. spinosissimus exhibited moderate reduction in the number of setae in the maxilla and maxillipeds, from the first to the second zoeal stage, when compared with other closely related species. Maguimithrax spinosissimus can be easily distinguished from other species belonging to the closely related genus Mithrax by the (i) setation of the endopod of the maxillule, maxilla and second maxilliped in both zoeal stages; (ii) setation of the scaphognathite of the maxilla in the first zoeal stage; (iii) setation of the basis of maxilliped I in the second zoeal stage and megalopa; (iv) morphology of the antennule and antenna in the second zoeal stage; and (v) setation of the antennule, coxal endite of maxilla, and exopod of second maxilliped in the megalopa. All these characters support the recent generic status of Maguimithrax within the Mithracidae. Additional morphological details, not available previously, are provided. This study will provide support for conservation strategies in this species.

Swimming propagules (embryos and larvae) are a critical component of the life histories of benthic marine animals. Larvae that feed (planktotrophic) have been assumed to swim faster, disperse farther and have more complex behavioural patterns than non-feeding (lecithotrophic) larvae. However, a number of recent studies challenge these early assumptions, suggesting a need to revisit them more formally. The current review presents a quantitative analysis of swimming speed and body size in planktotrophic and lecithotrophic propagules across five major marine phyla (Porifera, Cnidaria, Annelida, Mollusca and Echinodermata). Results of the comparative study showed that swimming speed differences among ciliated propagules can be driven by taxonomy, adult mobility (motile vs sessile) and/or larval nutritional mode. On a phylogenetic level, distinct patterns emerge across phyla and life stages, whereby planktotrophic propagules swim faster in some of them, and lecithotrophic propagules swim faster in others. Interestingly, adults with sessile and sedentary lifestyles produce propagules that swam faster than the propagules produced by motile adults. Understanding similarities and differences among marine propagules associated with different reproductive strategies and adult lifestyles are significant from ecological, evolutionary and applied perspectives. Patterns of swimming can directly impact the dispersal/recruitment potential with incidence on the design of larval rearing methods and marine protected areas.

The present study describes the morphological changes of the mouthparts and foregut of the freshwater prawn M. acanthurus that occur during the development of the larvae and first juvenile. The results indicate that the zoeae I have mouthparts with reduced setae and a structureless foregut that indicates obligatory lecithotrophic behaviour. There is an increase in the number of setae in these structures between the zoea II and the juvenile stage, indicating the adaptation of the organism for feeding. More complex structural alterations were observed in the first juvenile, which acquires benthonic habits, which ensure the capture and ingestion of a diversity of feeding resources found in the substrate.

The sexuality of large (non-dwarf) individuals and the characteristics of eggs, larvae and dwarf males were investigated in the pedunculate barnacle Scalpellum stearnsii. All 103 large individuals collected in this study were not hermaphrodites but females. The major length axis of the egg was on average 0.50 mm, which was larger than that in most thoracican barnacles with planktotrophic larvae. The larvae hatched as nauplii and metamorphosed into cyprids without feeding (i.e. lecithotrophic development). There was a positive relationship between body weight and egg mass weight in ovigerous females. The number of males attached per female ranged from 0 to 35 (average: 5.9) and there was a positive relationship between the number of males and female body weight. The distribution of dwarf males was skewed significantly towards the lower part of the occludent margin, which is near the fertilization site.

The size of the protegulum on the valves of Early Palaeozoic rhynchonelliform brachiopods has previously been used as a criterion to assign various taxa to either a planktotrophic or a lecithotrophic larval mode. A more reliable quantitative character is evaluated in juvenile samples of two genera from the Ordovician Mifflin Formation, the presumed planktotrophic orthid Doleroides pervetus and the presumed lecithotrophic atrypid Protozyga nicolleti, using the coefficient of variation in measurements of protegular size. The Doleroides sample has a significantly higher coefficient of variation than does the Protozyga sample. The results are in accord with observations on living marine invertebrates which indicate that at settlement (when mineralisation of the protegular mantle in brachiopods occurs), planktotrophic larval size is more variable than larval size in lecithotrophs because of fluctuations in food availability and duration of the planktonic phase. This result confirms that protegular size variance can be used to make inferences about larval trophic mode.