Antonio P. Ariani

Reappraisal and range extension of non-indigenous Mysidae (Crustacea, Mysida) in continental and coastal waters of eastern France

A survey of species belonging to the family Mysidae, conducted in June 2007 in fresh- to brackish waters of eastern France, revealed a recent range extension of the invasive Ponto-Caspian species Hemimysis anomala to the Moselle, Saône, and Rhône rivers. In the estuary of the Grand Rhône it reached for the first time the Mediterranean coast. The network of navigation canals in NE France was likely a key element of its north to south pathway starting from the Rhine River. Important range extensions were also noted for Limnomysis benedeni in this network and in the Moselle River. The euryhaline species Neomysis integer, endemic in coastal waters of the NE Atlantic, was found in the Rhône delta, thus confirming previous very rare records in the 1930–1950s from the Mediterranean coast of France. Invasion mechanisms and pathways, expansion potential, and establishment conditions of the species are discussed.

Comparative morphology and actuopalaeontology of mysid statoliths (Crustacea, Mysidacea)

SummaryA comprehensive and comparative study of the external statolith morphology of the family Mysidae is presented. The study covers 48 species from major systematic groups occupying a large number of habitats in different biogeographical zones of the globe. Statoliths generally show high morphological diversity. The traditional classification scheme of subtaxa and the correlation of statolith characters with segmentation patterns of body appendages suggest that the organic composition and the nearly spherical structure of the statoliths of Boreomysinae and Rhopalophthalminae are plesiomorphic compared with the more complex mineralized statoliths found in all other subfamilies. During ontogenetic development the number of sensorial setae and associated pores and pore groups on the statolith increase with body size and statolith diameter. Although patterns of caudal pores are highly specific for some genera, the high intraspecific variance of pore numbers strongly reduces the diagnostic value of this feature in most species. Statolith characters can be successfully used for identification of subfamilies, tribes, and especially genera. For future palaeontological applications a proper diagnosis of fossil mysid statoliths is essential. Therefore, we provide a key to subfamilies and tribes based exclusively on statolith characters.

Feeding, Reproduction, and Development of the Subterranean Peracarid Shrimp Spelaeomysis bottazzii (Lepidomysidae) from a Brackish Well in Apulia (Southeastern italy)

Abstract A population of the ‘eyeless’ hypogean shrimp Spelaeomysis bottazzii was studied over a three-year period in a shallow brackish-water well about 1 km from the Mediterranean coast. Mature males and immature females were numerous year round, whereas breeding females and juveniles were rare. The main stages of young in the brood pouch were embryos, nauplioids, and postnauplioids; all were unpigmented, unlike the postnauplioids in a congeneric species. In this well, the free-living stages fed mainly on autotrophic micro-organisms. The accumulation of fat reserves was judged from the amount of subcuticular fat bodies and from body colour. Fat status improved with increasing body size in both sexes; seasonal variations were not significant. Only ‘fat’ specimens produced eggs. Females incubating eggs were fatter than those with larvae. Field and laboratory findings suggest that fat accumulation near the photic zone is necessary for egg formation, whereas larval incubation is very long and mostly occurs elsewhere, probably in deep groundwater under unfavourable nutritional conditions. The observed post-reproductive reduction of oöstegites may indicate a peculiar strategy to avoid a new breeding cycle before reconstitution of fat reserves. The findings on feeding and reproduction, particularly regarding fecundity and natality, are interpreted as a combination of typically hypogean features along with epigean environmental adaptations.

The species complex of Diamysis Czerniavsky, 1882, in fresh waters of the Adriatic basin (NE Mediterranean), with descriptions of D. lacustris Băcescu, 1940, new rank, and D. fluviatilis sp. nov. (Mysida, Mysidae)

Most populations of Diamysis Czerniavsky, 1882, living in freshwater tributaries of the Adriatic Sea, belong to D. fluviatilis sp. nov., which is distinguished from its congeners mainly by the peculiar distribution of fringes on the carapace of males. A small number of freshwater bodies is inhabited by the more euryhalobious D. mesohalobia heterandra Ariani & Wittmann, 2000. A first description is given for adults of both sexes of D. bahirensis mod. lacustris Băcescu, 1940, formerly known only from one subadult female taken in the near-coastal freshwater lake Scutari (SE Adriatic). This taxon is raised to species level as D. lacustris, based on the shallow telson cleft and the undulate margins of the scutellum paracaudale in both sexes, and on peculiar features of the male. All freshwater records of Diamysis species so far confirmed for the Mediterranean are restricted to tributaries of the Adriatic basin. This is possibly related to transgressive-regressive events during the Pliocene-Pleistocene, causing alternations between marine and freshwater-terrestrial phases in this semi-enclosed basin, particularly in the area where the sedimentary basin of the Po river evolved.

THE TRANSITION FROM AN EPIGEAN TO A HYPOGEAN MODE OF LIFE: MORPHOLOGICAL AND BIONOMICAL CHARACTERISTICS OF DIAMYSIS CAMASSAI SP. NOV.(MYSIDACEA, MYSIDAE) FROM BRACKISH-WATER DOLINAS IN APULIA, SE-ITALY

A new representative of the mainly Mediterranean and Pontocaspian genus Diamysis Czerniavsky is described from a system of brackish-water dolinas near the Ionian coast of southern Italy (eastern Mediterranean). Most life stages mainly dwell in microalgal beds on hard substrata or among macrophytes inside well-illuminated dolinas, whereas incubating females and neonates are relatively more abundant in dimly-lit or dark dolinas. D. camassai sp. nov. is distinguished from its congeners by a relatively small cornea and short eyestalks with larger scales at their basis, as well as by a complex of characters affecting the carpopropodus of the thoracic endopods and the exopod of the male fourth pleopod. Relatively small eyes, dense setation on the legs, and large eggs point to a certain degree of adaptation to a subterranean mode of life, albeit that the animals are strongly pigmented and essentially micro-herbivorous. The stygophilic characteristics of this Diamysis may represent an important intermediate stage in the evolution towards stygobionts, which occur in the closely related genera Troglomysis Stammer (Mediterranean) and Antromysis Creaser (Caribbean).

An Adjusted Concept for a Problematic Taxon, Paramysis Festae Colosi, 1921, with Notes on Morphology, Biomineralogy, and Biogeography of the Genus Paramysis Czerniavsky, 1882 (Mysida, Mysidae)

[The type series of Paramysis festae Colosi, 1921, contained material from two different genera. Nonetheless the specific status of P. festae is confirmed, based on a revised set of characters. Its acknowledged distribution is restricted again to the type locality, a brackish lagoon on the coast of Libya. First records are given for P. bacescoi Labat, 1953, in the Mediterranean (Levantine Sea), and for P. helleri (G. O. Sars, 1877) and P. agigensis Băacescu, 1940, in the Sea of Marmora. New records support the previously not acknowledged occurrence of P. helleri in the Black Sea. Not counting the doubtful taxa P. proconnesia Colosi, 1922, and P. portzicensis Nouvel, 1950, a total of ten species of the genus Paramysis Czerniavsky, 1882, is definitively acknowledged for the NE-Atlantic, Mediterranean, and Marmora basins. A key to these ten species is given. Among 15 species of the genus Paramysis examined, 14 have statoliths mineralized with vaterite (CaCO 3 ); only P. arenosa (G. O. Sars, 1877) has fluorite (CaF 2 ). Among the vaterite-bearing species, a Ponto-MediterraneanAtlantic group with seven species is marked by thoracic sternites with smooth median processes, clearly different from sternites with hair-like or spine-like scales in six Ponto-Caspian and one Anatolian species. Together with published data on the fossil record and genetics, the new findings on the distribution, morphology, and statolith composition in Ponto-Mediterranean and Pontic species of Paramysis fit well to scenarios of remote Paratethyan origin, possible divergence of taxa in the Messinian Mediterranean, and later return of some descendants to the Black Sea. Das Typenmaterial von Paramysis festae Colosi, 1921, enthielt Individuen aus zwei verschiedenen Genera. Basierend auf revidierten Merkmalen wurde der Status von P. festae dennoch am Artniveau bestatigt. Die anerkannte Verbreitung von P. festae wird neuerlich auf die Typlokalitat, eine brackige Lagune an der Kuste Libyens, reduziert. Erstnachweise erfolgten fur P. bacescoi Labat, 1953, im Mittelmeer (Levante Becken), und fur P. helleri (G. O. Sars, 1877) plus P. agigensis Băcescu, 1940, im Marmarameer. Neue Belege bestatigten das zuvor verworfene Auftreten von P. helleri im Schwarzen Meer. Nach Abzug der fraglichen Taxa P. proconnesia Colosi, 1922, und P. portzicensis Nouvel, 1950, verbleiben insgesamt zehn als sicher anzuerkennende Arten der Gattung Paramysis Czerniavsky, 1882, fur den Einzugsbereich von NO-Atlantik, Mittelmeer und Marmarameer. Ein Bestimmungsschlussel wird fur diese zehn Arten gegeben. Von 15 untersuchten Arten der Gattung Paramysis hatten 14 Arten Statolithen aus Vaterit (CaCO 3 ), einzig P. arenosa (G. O. Sars, 1877) aus Fluorit (CaF 2 ). Unter den Arten mit Vaterit Statolithen konnte eine pontomediterran-atlantische Gruppe mit sieben Arten durch oberflachlich glatte, mediane Fortsatze an den Thorakalsterniten von sechs pontokaspischen und einer anatolischen Art mit beschuppten Sterniten klar abgegrenzt werden. Zusammen mit publizierten Fossilbefunden und genetischen Daten, passen die neuen Befunde zur Verbreitung und Anatomie der Arten und zur Zusammensetzung der Statolithen bei den ponto-mediterranen und pontischen Paramysis Arten gut zu Szenarien zeitlich ferner Herkunft aus der Paratethys, moglicher Aufspaltung von Taxa im Mittelmeer wahrend des Messinians, und spaterer Ruckkehr einiger Abkommlinge in das Schwarze Meer. , The type series of Paramysis festae Colosi, 1921, contained material from two different genera. Nonetheless the specific status of P. festae is confirmed, based on a revised set of characters. Its acknowledged distribution is restricted again to the type locality, a brackish lagoon on the coast of Libya. First records are given for P. bacescoi Labat, 1953, in the Mediterranean (Levantine Sea), and for P. helleri (G. O. Sars, 1877) and P. agigensis Băacescu, 1940, in the Sea of Marmora. New records support the previously not acknowledged occurrence of P. helleri in the Black Sea. Not counting the doubtful taxa P. proconnesia Colosi, 1922, and P. portzicensis Nouvel, 1950, a total of ten species of the genus Paramysis Czerniavsky, 1882, is definitively acknowledged for the NE-Atlantic, Mediterranean, and Marmora basins. A key to these ten species is given. Among 15 species of the genus Paramysis examined, 14 have statoliths mineralized with vaterite (CaCO 3 ); only P. arenosa (G. O. Sars, 1877) has fluorite (CaF 2 ). Among the vaterite-bearing species, a Ponto-MediterraneanAtlantic group with seven species is marked by thoracic sternites with smooth median processes, clearly different from sternites with hair-like or spine-like scales in six Ponto-Caspian and one Anatolian species. Together with published data on the fossil record and genetics, the new findings on the distribution, morphology, and statolith composition in Ponto-Mediterranean and Pontic species of Paramysis fit well to scenarios of remote Paratethyan origin, possible divergence of taxa in the Messinian Mediterranean, and later return of some descendants to the Black Sea. Das Typenmaterial von Paramysis festae Colosi, 1921, enthielt Individuen aus zwei verschiedenen Genera. Basierend auf revidierten Merkmalen wurde der Status von P. festae dennoch am Artniveau bestatigt. Die anerkannte Verbreitung von P. festae wird neuerlich auf die Typlokalitat, eine brackige Lagune an der Kuste Libyens, reduziert. Erstnachweise erfolgten fur P. bacescoi Labat, 1953, im Mittelmeer (Levante Becken), und fur P. helleri (G. O. Sars, 1877) plus P. agigensis Băcescu, 1940, im Marmarameer. Neue Belege bestatigten das zuvor verworfene Auftreten von P. helleri im Schwarzen Meer. Nach Abzug der fraglichen Taxa P. proconnesia Colosi, 1922, und P. portzicensis Nouvel, 1950, verbleiben insgesamt zehn als sicher anzuerkennende Arten der Gattung Paramysis Czerniavsky, 1882, fur den Einzugsbereich von NO-Atlantik, Mittelmeer und Marmarameer. Ein Bestimmungsschlussel wird fur diese zehn Arten gegeben. Von 15 untersuchten Arten der Gattung Paramysis hatten 14 Arten Statolithen aus Vaterit (CaCO 3 ), einzig P. arenosa (G. O. Sars, 1877) aus Fluorit (CaF 2 ). Unter den Arten mit Vaterit Statolithen konnte eine pontomediterran-atlantische Gruppe mit sieben Arten durch oberflachlich glatte, mediane Fortsatze an den Thorakalsterniten von sechs pontokaspischen und einer anatolischen Art mit beschuppten Sterniten klar abgegrenzt werden. Zusammen mit publizierten Fossilbefunden und genetischen Daten, passen die neuen Befunde zur Verbreitung und Anatomie der Arten und zur Zusammensetzung der Statolithen bei den ponto-mediterranen und pontischen Paramysis Arten gut zu Szenarien zeitlich ferner Herkunft aus der Paratethys, moglicher Aufspaltung von Taxa im Mittelmeer wahrend des Messinians, und spaterer Ruckkehr einiger Abkommlinge in das Schwarze Meer. ]