Guillermo Guerao

7 pages, 4 figures, 3 tables.[EN]The panopeid crab Dyspanopeus sayi (Smith, 1869) is reported here from the Ebro Delta (Mediterranean coast of the Iberian Peninsula). Originally endemic to the Atlantic coast of North America, D. sayi was involuntarily introduced into Britain, France and the Netherlands, and into the Adriatic and Black Sea within the last thirty years. Here we provide the first record of this species from the western Mediterranean Sea. Occurrences of ovigerous females at different localities of the delta and in different years provide evidence that the population is well established. Mitochondrial DNA confirms the identity of the species and indicates that the introduced population consists of at least three female lineages. The first zoeal stage of D. sayi was obtained in the laboratory from an ovigerous female captured in August 2010 with embryos in an advanced stage of development. The morphology of the zoea I is described here in detail and is similar to the one previously reported for native populations.[ES]Primera cita y evidencia de una población establecida del cangrejo americano Dyspanopeus sayi (Brachyura: Heterotremata: Panopeidae) en el Mediterráneo occidental. – Se informa de la presencia del cangrejo\ud panopeido Dyspanopeus sayi (Smith, 1869) en el Delta del Ebro (costa mediterránea de la Península Ibérica). Originalmente endémica de la costa atlántica de América del Norte, D. sayi se introdujo en Gran Bretaña, Francia, los Países Bajos, en el Adriático y el Mar Negro en los últimos treinta años. En el presente trabajo se presenta el primer registro de esta especie en el Mediterráneo occidental. La presencia de hembras ovígeras en diferentes localidades del Delta del Ebro y en diferentes años evidencia que la población está bien establecida. El ADN mitocondrial confirma la identidad de la especie e indica que la población introducida consiste de por lo menos tres linajes de hembras. El primer estadio de zoea de D. sayi se obtuvo en el laboratorio a partir de una hembra ovígera capturada en agosto de 2010, con embriones en una etapa avanzada de desarrollo. La morfología de la zoea I se describe en detalle, siendo similar a descripciones anteriores de poblaciones oriundas.Travel funds to CDS and students were made possible through an exchange program of the DAAD (D/03/40344) and the Spanish Ministerio de Ciencia y Tecnología – Acciones Integradas (HA2003-078), with José A. Cuesta as Spanish collaborator. Florian Gmeiner, Silke Reuschel and Lapo Ragionieri assisted during field collections in 2005 and 2006 respectively and students at the University of Regensburg helped with the molecular work. Financial support to GG (post-doctoral fellowship; INIA) was provided by the Ministry of Science and Research. The authors would like to thank Agustí Benito, fisherman of Sant Carles de la Ràpita for his collaboration in catching crabs. PA acknowledges research project CGL2009-12912-C03-03 from the Ministerio de Ciencia e Innovación (Spain). Paul Clark kindly made available important literature and shared his own unpublished description of the first zoeal stage of Dyspanopeus sayi.Peer reviewe

The early juvenile crab stages (C1 to C5) of the portunid crab Liocarcinus depurator (Linnaeus, 1758) were obtained in the laboratory from megalopae captured from the plankton in the northwest Mediterranean. Morphological development through these stages is described and compared with previous juvenile descriptions and adult morphology. The definitive adult morphology of carapace teeth is only apparent from stage C4. The incision on the lower orbital margin of the carapace and the mesial lobe (“portunid lobe”) of the endopod of the first maxilliped starts to be evident from C3. Stage C5 is already very similar to that of the typical adult crab. Male and female crabs can be distinguished from stage C2 onwards, based on sexual dimorphism in pleopods. The morphology and size of Mediterranean juvenile crabs was compared with the previous description of individuals reared in the laboratory from ovigerous females from British North Atlantic waters.

The mysid Hemimysis lamornae mediterranea Bacescu, 1936 is described from specimens sampled in the Ebro Delta, Spain, north-western Mediterranean. To date, this subspecies was only known from the Gulf of Naples and Marseille; this is the first record of the H. lamornae mediterranea on the Iberian Peninsula coast. Hemimysis lamornae mediterranea is distinguishable from its closest congeners, H. lamornae typica (Couch, 1856) and H. lamornae pontica (Czerniavsky, 1882) by the number of setae, the shape of the maxilla, and the relatively smaller number of spines on the uropod endopod and on the lateral margin of the telson.

The complete larval development of a sesarmid crab from East Africa, Chiromantes eulimene (De Man 1895) was obtained through laboratory culture. It consists of five zoeal stages and a megalopa, followed by metamorphosis to the first juvenile crab. The morphology of all zoeal stages is revised and compared with previous descriptions. The megalopa and the first juvenile crab stage are, for the first time, fully described in detail and compared with those of other known species of the genus Chiromantes and further sesarmid crabs. The megalopal morphology of C. eulimene presents the typical combination of features that characterize sesarmid megalopae. The first crab stage is also similar to that of other sesarmid species, for which morphological descriptions are available.

Gammarus aequicaudais a euryhaline amphipod that is a common inhabitant of brackish environments of the Mediterranean Sea. In the Ebro delta, the population density ofG. aequicaudais highly variable throughout the year. The main objective of this study is to investigate the effect of salinity on the growth ofG. aequicaudajuveniles.G. aequicaudaembryos and juveniles can survive and grow in the laboratory between 2 psu and 40 psu salinity, depending on the previous acclimation period for the reproductive individuals. Adults acclimated at 34 psu produced embryos and juveniles that survived and developed at salinities between 9 psu and 40 psu; adults acclimated at 9 psu produced embryos and juveniles that could develop in oligohaline conditions. The lower growth rate values were 10.9 μm d⁻¹and 13.5 μm d⁻¹at 40 psu and 2 psu, respectively, with the higher values of 18.0 μm d⁻¹and 18.5 μm d⁻¹at 19 and 34 psu, respectively.

The morphology of the different larval stages (zoea I, zoea II and megalopa) of the majid crab Maja squinado Herbst, 1788 Herbst, J. F. W. 1782–1804. Versuch einer Naturgeschichte der Krabben und Krebse, nebst einer systematischen Beschreibung ihrer verschiedenen Arten.. Berlin and Straslund, : 1–62. Vol. 1–3: 1–515 + p1 [Google Scholar] reared under laboratory conditions is described. The description of M. brachydactyla Balss, 1922 larvae is also revised, both from individuals reared in laboratory conditions and those collected from plankton samples. The larval stages of M. squinado are morphologically similar to those of the Atlantic species M. brachydactyla; the larval morphology does not justify the separation of M. squinado into two species. Larvae of M. brachydactyla obtained from the wild were similar to those reared under laboratory conditions. The morphology of the zoeal and megalopal stages of M. squinado and M. brachydactyla described in this paper have been compared with previous descriptions of the genus Maja, including M. brachydactyla (described as M. squinado).