Regional scale speciation reveals multiple invasions of freshwater in Palaemoninae (Decapoda).-Zoologica Scripta, 41, 293-306. The generic level, systematic relationship in Palaemoninae was inferred from analyses based on the mitochondrial 16S rDNA and nuclear Histone (H3) genes, primarily focussed on the genera Palaemon and Palaemonetes, as previous morphological and molecular studies indicated potential paraphyly in some genera. Palaemonetes, Exopalaemon, Coutierella and certain Palaemon recover as a strongly supported monophyletic clade, but with the exception of Palaemon concinnus, P. pandaliformis and P. gracilis. Within this clade, six major clades are identified with geographic relationships appearing stronger than generic relationships. The data strongly suggest that Palaemon, Palaemonetes, Exopalaemon and Coutierella are synonymous and that the morphological characters currently used to define these genera require re-evaluation. Freshwater species are not closely related to each other, but instead group with geographically close marine species, suggesting multiple invasions of freshwater by physiologically plastic ancestors rather than a single colonisation event with subsequent speciation.

Recent phylogenetic work (Ashelby et al., 2012) has demonstrated the need for a fresh appraisal of the systematic status of some Palaemoninae genera. In the present contribution the accumulated morphological as well as molecular evidence is reviewed. The genera Palaemonetes, Exopalaemon and Coutierella are demonstrated to be junior synonyms of Palaemon, which now contains 83 species. As a result of this systematic re-arrangement, two replacement names are needed. Palaemon kwantung nom. nov. now replaces Exopalaemon guangdongensis Guo, Wang & Zhang, 2005, nec Palaemon guangdongensis Liu, Liang & Yan, 1990. Palaemon mundusnovus nom. nov. is the replacement name for Palaemonetes intermedius Holthuis, 1949, nec Palaemon intermedius (Stimpson, 1860).

This paper details the ¢rst recorded instance of the prawn Palaemon macrodactylus in Europe, at the Orwell estuary, Su¡olk. The species is native to north-east Asia, including Japan and Korea, and has previously been introduced to other areas outside its natural range. Records of the abundance of caridean species, obtained from routine benthic trawl samples in the Stour and Orwell estuaries, provide a summary of P. macrodactylus' habitat preference in reduced-salinity waters. Consistent catches and records of ovigerous females provide evidence for the stability of the Orwell population. A revised key to British Palaemonidae is also provided.

Single-author papers are the lowest relative contributors to the research output of international open access journals BioInvasions Records (BIR), Aquatic Invasions (AI) and Management of Biological Invasions (MBI), accounting for 5% or less of published papers. In contrast, papers by four or more authors are the highest contributors, accounting for over half of the research output for the three journals. Papers by two or three authors are intermediate between these extremes, accounting for 15-23% of research ouputs. The relative contributions of research papers by single-authors to the output of AI and MBI has also significantly declined over time, while concurrently those by four or more authors has significantly increased. Although not significant, a similar pattern is also evident in BIR. Considering invasion ecology research, factors such as increasing globalisation, the increasing use of transboundary data-sets for invasive species and the proliferation of collaborative multidisciplinary author teams with multiple skill-sets, may be driving single-author papers to extinction.

In the latter half of the 20 th Century and the early part of the 21 st the Asian shrimp species Palaemon macrodactylus began being reported from several worldwide locations. Literature records of Palaemon macrodactylus are herein collated, corroborated through examination of material where possible. Material from each main occupied region has been verified as P. macrodactylus, but records from Taiwan and Darwin do not refer to P. macrodactylus. Some records still require verification in the absence of material examined. The data show that, in most cases, the first occurrence of P. macrodactylus in a region is several years prior to the detection of the species. Biological, ecological and physiological aspects of the species are summarised to gain an understanding of why the species is such a successful invader. However, the factors favouring the introduction of P. macrodactylus over other species of Palaemon remain unclear as many traits are shared with other species of the genus. Information on larval tolerances may provide further clues for the success of P. macrodactylus. We hypothesise that the global distribution of the species has been achieved through a combination of at least three primary introductions from Asia and three secondary introductions, but the origin of the Argentinean population remains unclear. Small-scale secondary introductions have likely aided spread within a region. Regions at risk of invasion by P. macrodactylus include the Baltic Sea, southern Norway and South Africa, whilst further spread within occupied, broad regions should be expected. RÉSUMÉ Pendant la deuxième moitié du 20 ème siècle et au début du 21 ème siècle, la crevette asiatique Palaemon macrodactylus commençait à apparaitre dans plusieurs régions à travers le monde. Dans le présent travail tous les signalements antérieurs de P. macrodactylus sont rassemblés et corroborées, là où c'était possible, par l'examen du matériel. Les spécimens provenant des localités 4

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The mandibles of caridean shrimps have been widely studied in the taxonomy and functional biology of the group. Within the Palaemonoidea the mandibles reach a high level of structural diversity reflecting the diverse lifestyles within the superfamily. However, the majority of studies have been restricted to light microscopy, with the ultrastructure at finer levels poorly known. This study investigates the mandible of nine species belonging to six of the recognised families of the Palaemonoidea using SEM and analyses the results in a phylogenetic and dietary framework. The results of the study indicate that little phylogenetic information is conveyed by the structure of the mandible, but that its form is influenced by primary food sources of each species. With the exception of Anchistioides antiguensis, all species examined possessed cuticular structures at the distal end of the pars molaris (molar process). Five types of cuticular structures are recognised herein, each with a unique form, but variable in number, placement and arrangement. Each type is presumed to have a different function which is likewise related to diet.

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