Margarida Cristo

"First record of the spottail mantis shrimp, Squilla mantis (Stomatopoda, Squillidae), in the Ria Formosa lagoon (Algarve coast, southern Portugal)" published on 01 Jan 2017 by Brill.

The relative influences of local and regional factors on the distribution of passive dispersers may be altered by habitat degradation, partly via differential effects on species depending on their niche breadths. To study this, we compared the effects of local (pond, water and vegetation characteristics) and regional (Moran’s eigenvector maps) factors on passively dispersing large branchiopod crustaceans from two areas of the Iberian Peninsula differing in habitat condition (i.e. well preserved vs impacted). Species were arranged from generalists to specialists based on niche breadth. We hypothesised that (1) habitat degradation would favour functional homogenisation, resulting in higher occurrences of generalist species in the impacted area; because generalist species are likely to be less dependent on local factors, we also hypothesised that (2) regional factors would be more important in the impacted area. As predicted, the most generalist species had higher occurrences in the impacted area, resulting in functional homogenisation. Ultimately, this process affected metacommunity dynamics that were more influenced by regional than local factors because generalist species were widely distributed regardless of habitat degradation.

We investigated the phylogenetic relationships among the three presently recognized subspecies of the tadpole shrimp, Triops cancriformis, using mitochondrial 16S and 12S rDNA sequences. Our results indicate that the taxon is divided into two distinct lineages. One lineage is formed of T. c. cancriformis populations and samples from northern Spain that had been classified as T. c. simplex in the most recent literature. The second lineage comprises all populations of T. c. mauritanicus and northern African populations of T. c. simplex. These two main lineages separated 2.3 to 8.9 million years ago, based on the range of inferred molecular clocks recognized for crustacean mtDNA sequence divergence. Percentages of divergence are in the range reported for recognized species in other notostracan lineages and we therefore propose to recognize them as two species, Triops cancriformis and Triops mauritanicus. The latter would comprise two subspecies in northern Africa, one consisting of the Moroccan populations of the former T. c. mauritanicus, the other comprising the African populations of the former T. c. simplex. It also includes three as‐yet unnamed lineages. A comparison of morphological characters with the molecular data revealed that the former T. c. simplex cannot be reliably separated from T. c. cancriformis, using morphological characters that have hitherto been used to distinguish among subspecies of T. cancriformis. Our investigation is the first to demonstrate the presence of T. c. cancriformis in Africa (Tunisia). The genetic haplotypes of these populations are identical with haplotypes also occurring in Central and Western Europe, as well as in Sicily. Therefore, we hypothesize that the African populations of T. c. cancriformis represent a result of repeated long‐distance dispersal across the Mediterranean Sea.

The diet of Sepia officinalis was studied by examining the stomach contents of 522 specimens caught off the coast of the Algarve, Portugal. A total of 49 different prey items, belonging to six taxa (Polychaeta, Cephalopoda, Teleostei, Bivalvia, Crustacea and Gastropoda) was found, indicating opportunistic feeding behaviour. The diet was examined in relation to season, sex and size. The diet of males and females were similar. For small S. officinalis, crustaceans were more important in weight, whereas for larger specimens, fish were dominant. Seasonal differences in the diet were apparent but were shown to be possibly influenced by the cuttlefish size.

Daily ration estimates of Norway lobster ( Nephrops norvegicus ) from field samplings over a 24‐h cycle were obtained. Four tows were conducted in the middle continental slope, off the south coast of Portugal. The results from Eggers (1977, 1979) and Elliot & Persson (1978) daily ration models were compared, by the Worobec 8‐method (1984), showing no significant differences among them. The estimates of food consumption obtained varied from 1.098 to 1.170 g dry food per 100 g body wet weight in males and 1.642 to 1.755 g dry food per 100 g body wet weight in females. Our results were compared with daily rations reported for other crustaceans. Daily ration values were compared and tested by a two‐way ANOVA, with interaction, showing significant differences between sexes. This has been registered for other decapods and may be explained by a period of active growth in females, on the onset of vitellogenesis, increasing their nutritional/ feeding needs.

Estimates of gut evacuation rates of Nephrops norvegicus (Linnaeus, 1758) (Crustacea, Decapoda) were obtained during laboratory and field experiments. Individuals were collected off the south coast of Portugal in December 1997 and July 1998. Gut evacuation rates (R.h-1) were calculated from the slope of the regression of the natural logarithm of dry stomach content weight versus time, using data obtained by the serial slaughter method. The values obtained during laboratory (R=0.172 h-1) and field experiments (R=0.177 h-1) are compared with gut evacuation rates reported for other marine organisms. The results obtained for both experiments are within the range of the values in the literature, even in the case in which different methodologies were used.

The presence of non-cladoceran branchiopods was detected in only 16 out of 83 temporary freshwater ponds of SW Portugal, which were recently sampled by the authors and other researchers. Two anostracans, Branchipus cortesi and Chirocephalus diaphanus; two spinicaudatans, Cyzicus grubei and Maghrebestheria maroccana; and one notostracan, Triops cancriformis mauritanicus, were identified. All taxa are new records locally, and all but C. grubei and T. c. mauritanicus are reported for the first time from Portugal. La presence de Branchiopodes non Cladoceres a ete detectee dans 16 seulement des 83 mares temporaires d'eau douce du SO du Portugal, qui ont ete recemment echantillonnees par les auteurs et d'autres chercheurs. Deux Anostraces, Branchipus cortesi et Chirocephalus diaphanus, deux Spinicaudata, Cyzicus grubei et Maghrebestheria maroccana, et un Notostrace, Triops cancriformis mauritanicus, ont ete identifies. Tous les taxa sont nouveaux pour la faune locale et tous, sauf C. grubei et T. c. mauritanicus, sont signales pour la premiere fois du Portugal.

The stomach contents of 248 Norway lobsters were analysed. Prey specimens were identified to the lowest taxonomical level possible. The frequency of occurrence method was used to analyse the data and the results are presented considering only major groups. The results obtained indicate great diversity in terms of prey in the stomachs of Nephrops norvegicus, with a clear preference for decapods, followed by other crustaceans and fish. Seasonal changes in the diet were not significant; particularly for the major groups.