For the first time the meiofauna of the rocky walls of a submarine cave was studied. The cave, known as il Ciolo (Strait of Otranto, south-east Italy) is a closed tunnel about 125 m long, with a maximum depth of 6 m below sea level. The meiofauna was collected from artificial panels and natural rocky walls. This double approach enabled: (1) the description of the community's initial organization (on artificial substrata), and (2), especially for Harpacticoida, its mature composition (on rocky walls), which also helped to establish spatial differences. The collected samples yielded 70 taxa in total. Harpacticoida represented the most important group of organisms in terms of both abundance and identified taxa. The meiofauna assemblage appeared not to be affected by community age, with the exception of the very early stage. The meiofauna of the cave showed assemblage differences from the entrance to the innermost positions, but not as evident as in the case of the macrobenthos. The similarity of community composition at different ages (6, 12 and 24 months) and at different positions along the cave could be the consequence of the specimens’ vagility.

A new species of Paracrenhydrosoma (Copepoda: Harpacticoida: Cletodidae) is described from samples taken from muddy bottoms in Jangmok, Geoje Island, Korea. The genus Paracrenhydrosoma is distinguished from other genera of the Acrenhydrosoma-complex (Acrenhydrosoma, Dyacrenhydrosoma and Neoacrenhydrosoma) by carrying an antennal exopod with two setae, P1 endopod with three setae, P3 endopod with two setae and P5 exopod with two setae. The new species differs from its congeners as follows: bifid rostrum on anterior margin, long caudal ramus, exceedingly long baseoendopodal mucroniform process of female P5 that reaches the end of the second free abdominal segment, and modified P3 endopod of male. A tabular key to aid in the identification of the Acrenhydrosoma-complex is provided. The worldwide distribution of the Acrenhydrosoma-complex is summarized and discussed.

Mesophotic coral ecosystems (MCEs) are found on the insular and continental slopes of Caribbean islands and comprise mainly scleractinian corals, sponges and macroalgae. These species provide habitat for a highly diverse and specialized crustacean fauna. A new genus and species of the family Louriniidae is described from samples taken from an MCE in south-west Puerto Rico. The new taxa can be diagnosed by: body elongate, almost cylindrical and with inconspicuous podoplean boundary between prosome and urosome; double genital somite with a discontinuous chitinized cuticular ridge; telson short with rectangular anal operculum; furca short; rostrum sinusoidal, well defined at the base; antennules 7-segmented with aesthetasc on the fourth segment; antenna with a brush-like basal seta and an abexopodal seta, exopod 1-segmented with 2 setae; endopod with 7 elements (1 geniculate seta and 1 modified inner spine); maxilliped well developed, prehensile, composed of syncoxa, basis, one segmented endopod and one claw-like apical seta; leg 1 endopod 3-segmented, first segment with a modified inner seta; legs 2, 3 and 4 with 2-segmented endopod with inner seta on the first segment; leg 5 basendopod fused, well developed with 4 setae, exopod well developed, with 5 setae; leg 6 represented by a single seta; and genital slits wide apart. The new genus and species can be confidently assigned to the family Louriniidae on the basis of the following synapomorphies: rostrum well-developed with rounded tip; antennule of female 7-segmented; mandible palp reduced; maxillule endopod and exopod absent; maxillae endopodite 2 represented by 3 setae; leg 5 basoendopod of female confluent, intercoxal sclerite absent, exopod 1-segmented; eggs retained in a single ventral egg sac; telson shorter than last urosomite; and furca short and with 6 setae.

A new species of the genus Dahmsopottekina is described from the Mediterranean Sea. Dahmsopottekina guilvardi sp. nov. was collected from abyssal habitats at a depth range of 2340–2850 m. Like its congeners, the new species has a vermiform habitus, a highly transformed P1 in both sexes and a plough-like rostrum in the female. Dahmsopottekina guilvardi sp. nov. can be distinguished from its congeneric species by the combination of a fused basis and endopodite in P1 of both sexes and the absence of an endopodite in P2–P4 of the female. Dahmsopottekina guilvardi sp. nov. is the second record of a harpacticoid species after its congener D. peruana in which the basis and endopodite of a leg other than the P5, namely the P1, are fused. Furthermore, the new species is the only one among Dahmsopottekina species with a 1-segmented P1 exopodite in the male. Similar to its congeners, D. guilvardi sp. nov. is strongly sexually dimorphic. This is evident through the morphology of most of the cephalic appendages and the reduction of P2–P6 in the female. The results of the present study support the observation that Dahmsopottekina species are sparsely distributed and highly endemic. Nevertheless, our results do not agree with the statement of considerably larger females as the length variability between females is greater than between the two sexes. Despite the morphological characters of the species commensurate with a burrowing mode of life, its presence in sediment traps suggests that D. guilvardi sp. nov. is an active ‘swimmer’.

We provide a review on scientific contributions concerned with Leptocaris (Harpacticoida: Copepoda) that includes the zoogeography, ecology, biology, and morphology of this genus. A tabular key is given to aid in the identification of the ignavus-group. Leptocaris ryukyuensis sp. nov. is included on the basis of specimens collected from Akeijima sandy beach of the Ryukyu Islands in Japan. The new species can be distinguished from its congeners by an abexopodal seta and 3 exopodal setae on A2, a barbed inner seta on the proximal, endopodal segment of female P1 to P3, setae of the caudal ramus (setae I and II are very small, and the basal seta is transformed to a big spine), and modified inner setules of P2 enp-2 and P3 enp-2 in the males. The new species belongs to the ignavus-group established by Kunz (1994) and is the third species of the genus Leptocaris in East Asia.

After examination of 44 populations of Attheyella (Brehmiella) wulmeri (Kerhervé, 1914) (Copepoda : Harpacticoida) from Montenegro (SE Europe), its taxonomic status is revised. Three new synonyms of this species are established : A. (B.) osmana Kiefer, 1955, A. (B.) naphtalica Por, 1983, and A. (B.) paranaphtalica Pesce & Galassi, 1988. Detailed description, map of distribution, as well as a review of all important variable characteristics are presented.

Elaphoidella plesai n. sp. is described from material collected from cave waters of Austria. According to Apostolov (1985) the new species fits the gracilis group of Elaphoidella s. str., being close to Elaphoidella stammeri Chappuis, 1936. It differs from the nominate species, as well as from other congeners in the same group, by the distinctive morphology and setation of caudal rami, and by the unusual armature of leg 5.

Description de Parastenocaris bulgarica n.sp., récoltée dans la grotte "Douchnica" au nord-ouest de la Bulgarie.

Trois nouvelles espèces d'Harpacticoïdes : Elaphoidella cavernicola n.sp., E. balkanica n.sp. et E. pandurskyi n.sp., découvertes dans les eaux cavernicoles de Bulgarie sont décrites.

Deux nouvelles espèces d'Harpacticoïdes, Stygoelaphoidella bulgarica n. sp. et S. elegans n. sp. découvertes dans les eaux cavernicoles de Bulgarie sont décrites.

64 échantillons collectés par le Professeur Th. Monod en 1971 dans les eaux intérieures des Açores lors d'une missionà terre de la campagne Biaçores ont été examinés. Dix sept espèces et sous-espèces ont été identifiées dont onze nouvelles pour les Açores. Eucyclops agiloides açorensis et Metacyclops mendocinus insulensis sont décrites comme sous-espèces nouvelles. La présence des différentes espèces reconnues dans ces îles, ainsi que leur répartition géographique, sont commentées.

Description de Parastenocaris nertensis n. sp. et Parastenocaris fontinalis meridionalis n. s. sp. récoltées dans le sous-écoulement d'un ruisseau des Pyrénées.

Stygoelaphoidella stygia n. sp. est décrite d'une grotte dans les Vasilijovska Mountains du Nord de la Bulgarie et d'une petite rivière dans la grotte du village de Lipnitza - District de Sofia - en Bulgarie occidentale.

La découverte d'une nouvelle espèce d'Elaphoidella, dans une région karstique apparemment bien prospectée, montrel'intérêt de prendre en compte la zone noyée des karsts si l'on veut réellement connaître la faune aquatique souterrainedes pays calcaires.

Le peuplement des Crustacés du sous-écoulement du ruisseau de Lachein (Pyrénées) a été étudié sur un site de 75 m2 et à une profondeur de 0,60 m.Les écoulements de surface déterminent quatre zones principales, deux bancs de graviers, un chenal et une zone d'eau morte. La porosité (20 à 30 %), plus élevée dans les bancs de graviers que dans le chenal, est également plus forte à l'amont des bancs qu'à l'aval. La granulométrie diffère selon les zones, les bancs de graviers étant caractérisés par une plus forte abondance des éléments mesurant 1 à 8 mm. Les caractéristiques chimiques du sous-écoulement, toujours proches de celles du cours subaérien, évoluent de façon identique à ces dernières au cours des saisons. Les valeurs de l'O2 dissous, proches de la saturation en surface, sont comprises entre 0,02 % et 84,7 % dans le sous-écoulement où leur distribution dépend très directement de la dynamique des écoulements de surface. Les teneurs en matière organique particulaire, comprises entre 4 et 13,6 %, subissent une évolution saisonnière. Les valeurs moyennes les plus basses caractérisent le chenal.Les Crustacés, représentés par 50 espèces et sous-espèces. dont 22 taxons stygobies, montrent une forte similitude faunistique avec ceux colonisant le système karstique du Baget dont le ruisseau de Lachein est issu. Ils sont caractérisés par une organisation stable dans le temps, dominée par les Copépodes et, notamment, par les Harpacticides qui constituent 60 % du peuplement. Leur densité moyenne est de 369 individus/10 l. La répartition spatiale des Malacostracés comme des Harpacticides est très variable, avec des espèces eurytopes (formes épigées) et sténotopes (formes hypogées) ; parmi ces dernières, les unes sont inféodées aux zones les plus oxygénées, d'autres au contraire, sont limitées aux zones les moins oxygénées. Chez les Harpacticides, les densités comme les pourcentages des formes hypogées sont très directement liés aux différentes zones définies par les écoulements de surface.