Raül Triay-Portella

Ovarian maturity, egg development, and offspring generation of the deep-water shrimp Plesionika edwardsii (Decapoda, Pandalidae) from three isolated populations in the eastern North Atlantic

ABSTRACT Ovarian maturity, egg development and brood size were analysed for three isolated populations (Madeira, the Canary Islands and Cape Verde Islands) of Plesionika edwardsii (Decapoda, Pandalidae) in the eastern Atlantic. Multiple colour patterns were observed at the same ovarian maturity stage, which was verified histologically, invalidating the extensive use of ovarian colour as a maturity stage criterion. The physiological size at sexual maturity, based on the maturity of the ovaries, was higher in Madeira (carapace length of 19.73 mm) and decreased to the Cape Verdes (16.39 mm). Synchronic ovarian maturation was observed during the embryo incubation process, and ovigerous females bearing embryos at the final stage of development were found throughout the year. Females are multiple spawners during the reproductive season, after which the reproductive process ends and a rest period begins. The absence of females larger than the size at sexual maturity with ovaries in Stage 1, the incubation of embryos in the final developmental stages, suggests that the resting period begins with a process that reabsorbs the energy located in the ovaries and that the resting period occurs asynchronously in females in each of the studied populations. Embryo size was independent of female body size in the three populations studied, but increased with the developmental stage. A power equation was used to describe the relationship between brood size and female body size in the three areas studied. The mean number of external Stage I embryos carried by females decreased from Madeira (n = 7868) to the Cape Verdes (n = 3781), where less energy, in terms of the number of embryos and the size of the eggs, was invested in reproduction. Although female size decreases from north to south, the egg number was higher in Madeira than in the Cape Verdes for the same size range.

A new species of Physiculus (Teleostei: Moridae) from the Cape Verde Islands (Eastern Central Atlantic)

A new species of Physiculus, P. caboverdensis n. sp., is described from the outer shelf and upper slope of the Cape Verde Islands. This species differs from all other congeners from the Atlantic Ocean by its peculiar dentition, composed of large fang-like teeth in both jaws, interspaced with smaller canine-like teeth, arranged in two series on upper jaw and one on lower. This is the tenth species of the genus to occur in the Atlantic Ocean and the third to be recorded from the Cape Verde Islands.

Perception of faunal circadian rhythms depends on sampling technique

Ecologists aim at disentangling how species vary in abundance through spatial and temporal scales, using a range of sampling techniques. Here, we investigated the circadian rhythm of seagrass-associated decapod crustaceans through three sampling techniques. Specifically, we compared the abundance, biomass and structure of seagrass-associated decapod assemblages between the day and night using a hand net, an airlift pump and baited traps. At night, the hand-net consistently collected a larger total abundance and biomass of decapods, what resulted in significant diel differences, which were detected for the total biomass, but not for the total abundance, when decapods were sampled through an airlift pump. Traps, however, collected a larger total abundance, but not total biomass, of decapods during the night. In summary, our perception of faunal diel rhythms is notably influence by the way organisms are sampled.

Three new decapods (Aristeidae, Chirostylidae, Pandalidae) from the Cape Verde Islands (NE Atlantic)

In the present article three benthic decapods, Aristeus varidens Holthuis, 1952 (Aristeidae), Gastroptychus formosus (Filhol, 1884) (Chirostylidae) and Plesionika longicauda (Rathbun, 1901) (Pandalidae), are recorded for the first time from the Cape Verde Islands. This is the southernmost record of G. formosus , as well as the northernmost of P. longicauda ever recorded from the eastern Atlantic. Preliminary data on batch fecundity and egg size of the pandalid shrimp are provided. Studied specimens were caught in the frame of a scientific trapping survey.

First record of three brachyuran decapods (Inachidae, Polybiidae, Thiidae) from the Canary Islands (NE Atlantic)

In the present account three brachyuran decapods, Macropodia linaresi Forest & Zariquiey Alvarez, 1964 (Inachidae), Liocarcinus navigator (Herbst, 1794) (Polybiidae) and Thia scutellata (Fabricius, 1793) (Thiidae), are recorded for the first time from the Canary Islands. This is the southernmost record of M. linaresi . Crabs were caught in the frame of a dredging survey. Characteristics of the dredge stations are given, including the identification of 11 accompanying decapod species and 6 marine algae and plants characterizing their habitats.