Invasive species alter ecosystems and harm economies. Improved understanding of past invasions can inform and improve current and future management efforts. We investigated the global and North American distribution of nonindigenous species (NIS) prior to their establishment in the Laurentian Great Lakes (GL). For the subset of NIS first recorded in North America in the GL, we also investigated the likelihood of these species to spread beyond the basin. With respect to biological invasions, we assessed if the GL basin is a beachhead (i.e., most NIS in the basin originating from outside North America) or a gathering place (i.e., most NIS arriving in GL already in North America). We found that the GL are both a beachhead and a gathering place, depending on the vector of introduction to the basin. Ballast water release introduces most beachhead NIS (43 of 65, 66%), whereas canals, authorized release, and unauthorized release primarly introduce gathering place NIS (67 of 101, 66%). Overall, gathering place NIS currently outnumber beachhead NIS in the GL (101 vs. 65). Regarding spread of beachhead NIS beyond the GL, we found that time elapsed since discovery in the GL predicts secondary spread with 87% accuracy. Our classification model suggests that beachhead NIS established populations outside the GL basin within 77 years of discovery there, suggesting that numerous NIS may be poised to spread beyond the GL basin in the near future. Given the established policy goal of both Canada and the United States to reduce harm from invasions, several recommendations arise from our analysis: (1) maintain, strengthen, and monitor the efficacy of ballast water regulations to prevent the introduction of additional beachhead NIS, (2) conduct risk assessments of NIS that are already in North America but not yet in the GL to prioritize management actions, and (3) seek regional coordination of regulations of vectors of gathering place NIS to shore up weak policy links.

No abstract

The study of the opisthobranch fauna from the Canary Islands had an inflection point in the 80’s, when a regular work with this group started. As a result, the number of species recorded or described in the Canaries has increased progressively, from the former inventory of 10 species, to the 287 that we know today. As a continuation of the global inventory of the fauna from the archipelago, 6 new species are described from singular localities in the Canaries. Key words: Mollusca, Opisthobranchia, new species, new records, Canary Islands.

The target species of this work is a large tritonid nudibranch, relatively common in Galician waters (north-western Spain), where it has been regularly observed since the year 2000. To date, this species has been misidentified as Tritonia hombergii, a species from northern latitudes, because of its remarkable size. On the other hand, the external anatomy of the specimens from north-western Spain resembles that of Marionia blainvillea, a species common in the Mediterranean. To untangle the real taxonomic identity of the species, a detailed anatomical study was performed, revealing several morphological differences that has led us to consider the Galician specimen as new to science. A phylogenetic analysis was conducted for both 16S and COI genes to try to establish its systematic position in relation with other taxa. Marionia gemmii, sp. nov. differs from all known Tritoniidae in the size, colour pattern, number of velar processes, presence of stomach plates, radular formula, the shape of spawning masses and even in its feeding habits. The phylogenetic results support the comprehensive morphological analysis and also make it clear that most tritoniid genera currently recognised are not monophyletic and that a major systematic revision of the family is needed. http://zoobank.org/urn:lsid:zoobank.org:pub:91332872-9020-4D06-8B1C-2E7654D54E1A

El inventario de las especies antillanas y caribeñas de marginélidos del género Volvarina Hinds, 1844 se ha incrementado en los últimos años, gracias a los aportes de