José María Landeira

Spatial variability of planktonic invertebrate larvae in the Canary Islands area

In October 1991, invertebrate larvae abundances were analysed to study the influence of the disturbance of the Canary Current flow by the Canary Islands archipelago on the variability of larval distribution. Two transects and two time-series stations located to the north (non-perturbed zone) and the south (perturbed zone) of the Canary Islands were sampled. Oceanographical data showed a highly stratified water column and zonally uniform salinity and temperature seaward of the African upwelling in the non-perturbed zone, while the perturbed zone presented strong turbulence in the form of mesoscale eddies. Invertebrate larval abundances were lower for most taxa studied in the non-perturbed zone and northern time-series station. Significant differences (P < 0.001) of invertebrate larval abundance between the two zones sampled were found. Decapod larvae were the most abundant larval group in both zones. Stations located in eddy structures presented the highest values of larval densities. Specifically, the larvae collected at Station 18, located in the core of an anticyclonic eddy, represented 60 ± 18% of total larvae collected in the south transect. Finally, our results suggest that eddies, mainly anticyclonic eddies, act as a strong larval retention zone south of the islands, and that there is a local northward transport from the Canary Islands.

Phylogenetics reveals the crustacean order Amphionidacea to be larval shrimps (Decapoda: Caridea).

We present evidence that the single representative of the crustacean order Amphionidacea is a decapod shrimp and not a distinct order. After reviewing available morphological evidence, it is concluded that Amphionides is a larval form, but with an as yet unknown parentage. Although the most likely adult form is in the family Pandalidae, the limited molecular data available cannot fully resolve its affinity. We therefore propose to treat Amphionides reynaudii as incertae sedis within Caridea, rather than a separate family. In view of the large scale, tropical and subtropical distribution of the taxon, the possibility is discussed that Amphionides is more likely to be a composite taxon at generic level, rather than larvae of a single shrimp species.

Description of the Decapodid Stage of Plesionika narval (Fabricius, 1787) (Decapoda: Caridea: Pandalidae) Identified by DNA Barcoding

The morphology of the decapodid stage of Plesionika narval (Fabricius, 1787) is described and illustrated based on larvae collected in the Canary Islands waters (NW Africa). Mitochondrial DNA analysis of the barcoding gene COI sequences confirmed the identity of the larvae specimens. Decapodid development of P. narval is compared with other pandalid and related genera Pandalus, Pandalopsis, Procletes, Stylopandalus, and Icotopus. Based on their morphological similarities we concluded that the nomina dubia genus Icotopus is a synonym of Plesionika and herein selected Plesionika over Icotopus as the valid name for the genus.

New data on the mesopelagic shrimp community of the Canary Islands region

During the “ZIFIOCAL 1” cruise, carried out around the islands El Hierro and Tenerife (Canary Islands, NW Africa), at depths between 200 and 750 m, 990 mesopelagic shrimps belonging to 29 species were identified. Many of these species are rare, and therefore the present records constitute new data on their vertical and biogeographical distribution. The collection of Sergia burukovskii represents a new record for the Canary Islands. Finally, the first finding of Ligur ensiferus displaying a pelagic distribution is also reported.

Colonization patterns of decapods into artificial collectors: seasonality between habitat patches

Understanding colonization of new habitats by recruits is essential to comprehend local abundance patterns of adult populations. Colonization of benthic habitats by new colonizers is achieved through the influx of larvae from the water column and movements from adjacent habitats. Colonization, i.e., the composition and abundance of new colonizers, into a focal habitat may be affected by surrounding habitats. In this study, we investigated seasonal variation through an annual cycle in postlarval settlement patterns of decapod crustaceans colonizing artificial collectors on different habitats, in particular: Cymodocea nodosa seagrass meadows, sandy patches, ‘urchin-grazed’ barrens and macroalgal-dominated beds, which are arranged in patches within seascapes in the eastern Atlantic. Our results showed that: 1) decapods, at least some species, settle preferentially on artificial collectors deployed on vegetated substrates when compared to those deployed on unvegetated substrates; 2) despite most decapods have a planktonic larval phase with wide oceanic dispersal, the presence of crustaceans in particular habitats suggests a great specificity at their early post-larval stages; and 3) although subtropical waters of Gran Canaria have a weak seasonal variation, early postlarval stages of decapod crustaceans showed two distinct settlement periods, i.e., a ‘cold’ and a ‘warm’ season.

First record of Pelagopenaeus balboae and Sergia wolffi (Decapoda, Dendrobranchiata) from the Canary Islands, with an annotated checklist of the Dendrobranchiata in the area

The Decapoda suborder of Dendrobranchiata has received little attention from carcinologists in waters around the Canary Islands (e.g., González & Santana, 2014). In his commented and illustrated catalogue on the Canarian decapods, González (1995) compiled all information available on this group of shrimps. This compilation included the historical records listed by Santaella (1973), as well as many species reported by Fransen (1991). In his impressive compilation, d’Udekem d’Acoz (1999) included the dendrobranchiate species previously reported for the Canaries. After this work, Quiles et al. (2001) newly recorded one penaeid and one sergestid from the Canary Islands, whereas Bordes (2009) catalogued several species of mesoand bathypelagic crustacean species from the waters of the Canary Islands. More recently, Landeira & Fransen (2012) identified 29 species of mesopelagic shrimps from off the western islands of the Canaries, including both Dendrobranchiata and Caridea, including an in-depth revision of Bordes’ inventory. Finally, González & Santana (2014) published an account of Penaeidae from the Canary Islands, with the first record of Penaeus kerathurus (Forskål, 1775). The superfamily Sergestoidea has been re-organized during the last two decades (Vereshchaka, 2000, 2009; Vereshchaka et al., 2014, 2015, 2016a, b), resulting in five distinct families: Luciferidae, Sergestidae, Acetidae, Sicyonellidae and Petalidiumidae (Vereshchaka, 2017). Molecular evidences are still needed to support this new classification, but the use of robust taxonomic characters, such

Morphological and morphometric variability in the zoea I larvae of Pugettia quadridens (De Haan, 1839): looking for reliable characters for taxonomic studies on the genus Pugettia Dana, 1851 (Majoidea: Epialtidae)

The larval morphology of Pugettia quadridens (De Haan, 1839) has been described several times, but the lack of voucher specimens (both larvae and spent females), makes it impossible to verify whether the remarkable heterogeneity, which has been described by the different authors, are due to intra-specific variability. We re-described the morphological and morphometric features of the first zoeal stage of the species, depositing voucher specimens for future examination by the scientific community. We used four females that were collected in the same locality in Hakodate Bay, Japan, and found significant morphological and morphometric intra-specific variability, both within and among clutches. One important variation was the setal count on the endopod of maxilla (3-4, rarely 5), which have been considered in previous studies to be a key character to distinguish species within genus Pugettia Dana, 1851. The size differences were rather striking, and the mean carapace length of the largest clutch (0.73 ± 0.04 SD mm) was up to 0.1 mm larger than the smallest one (0.63 ± 0.02 mm). We establish herein a solid taxonomic background for further larval descriptions of species of Pugettia with reliable characters and recommend the use of different clutches to prevent insufficient morphological descriptions due to intra-specific variability.