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A new species of Tortanus (Copepoda, Calanoida) from the Nansha Archipelago in the South China Sea
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A new species, Tortanus tumidus of the family Tortanidae (Copepoda, Calanoida) identified from zooplankton collected in the lagoon of Zhubi Reef in the Nansha (Spratly) Archipelago of the South China Sea is described and illustrated. Tortanus (Atortus) tumidus can be distinguished from other species of the subgenus by its posterior cephalic region, a small middorsal protrusion in both females and males, and by the shape of the male's right fifth leg. This species may be endemic to the Nansha Archipelago.
Une nouvelle espèce de la famille des Tortanidae, Tortanus tumidus (Copepoda, Calanoida), identifiée à partir de zooplancton récolté dans le lagon de Zhubi Reef, dans l'archipel Nansha (Spratly) de la mer de Chine méridionale, est décrite et illustrée. Tortanus (Atortus) tumidus se distingue des autres espèces du sous-genre par sa région céphalique postérieure, par une petite protubérance médiodorsale chez les mâles et les femelles, et par la forme de la cinquième patte droite du mâle. Cette espèce pourrait être endémique de l'archipel Nansha.
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Behavioural elements of the noble crayfish, Astacus astacus (Linnaeus, 1758)
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Based on contemporary literature and original observations under laboratory conditions, this paper attempts to compile a first comprehensive ethogram for the noble crayfish, Astacus astacus. Sixty-six behavioural elements are described, belonging to 12 functional cycles. Supplementary proposals are welcome. By comparing the ethograms of various species we may be able to obtain further indications to the phylogeny of the freshwater crayfish.
Auf der Grundlage aktueller Literatur sowie eigener Beobachtungen unter Laborbedingungen wird hier versucht, ein erstes umfassendes Ethogramm für den Europäischen Edelkrebs, Astacus astacus, zusammenzustellen. Es werden 66 Verhaltenselemente aus 12 Funktionskreisen beschrieben. Ergänzungsvorschläge sind sehr willkommen. Durch den Vergleich der Ethogramme verschiedener Flußkrebsarten sollte es möglich sein, neue Hinweise auf die Phylogenie dieser Gruppe zu gewinnen.
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Quality differences in feeding areas of the red crab, Pleuroncodes planipes Stimpson, as reflected from their lipid, fatty acids, and astaxanthin composition
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The red crab or "langostilla", Pleuroncodes planipes is abundant in the Pacific coast upwelling system of Baja California. It feeds both on plankton in the pelagic realm and on detritus in the benthic habitat. Previous studies of stomach contents suggested variations with latitude and depth, and potential differences in productivity. The aim of this study was to use the lipid and astaxanthin contents as well as the fatty acid composition of the red crab as a measure of its nutritional condition and thus of the quality of their feeding areas. Crabs were collected in September 1991 using a shrimp trawl at 6 stations on the continental shelf off the west coast of Baja California between 26° and 24° N. All samples were sun-dried and homogenized by grinding, prior to the extraction of total lipids. Astaxanthin content was also measured at each location. The methyl esters of the total fatty acids were analysed by capillary gas chromatography with flame ionization detection (FID). Lipids and astaxanthin contents varied significantly from shallow to deeper locations, and both organic compounds were significantly correlated (p < 0.05). The C16 : 0, C16 : 1, C18 : 0, C18 : 1, C18 : 2n-6, C18 : 3n-3, C20 : 4n-6, C20 : 5n-3, and C22 : 6n-3 fatty acids were identified and quantified. The most abundant fatty acid was C20 : 5n-3, ranging from 8.3 to 21.06 g/100 g TL, followed by C16 : 0 (3.4-14.10 g/100 g TL) and the C20 : 4n-6 (1.42-7.43). Fatty acids with the least statistical variation between locations were C18 : 3n-3 and C20 : 5n-3. Fatty acids from the different locations were found to be grouped into a latitudinal cline, suggesting red crabs are good indicators of areas with distinct food quality.
La langostilla o cangrejo rojo pelágico, Pleuroncodes planipes, es un abundante crustáceo decápodo del sistema de surgencias de la costa del Pacífico de Baja California. Se alimenta tanto en el hábitat pelágico (de plankton) como en el bentónico donde consume principalmente detritus. Estudios previos de contenidos estomacales mostraron una variación con la latitud y la profundidad, sugiriendo áreas de distinta productividad. El objetivo de este estudio fue usar el contenido de lípidos, astaxantina y composición de ácidos grasos de la langostilla como reflejo de su condición nutricional y de la potencial existencia de areas alimentación especificas. El crustáceo fue colectado en septiembre 1991 usando una red camaronera sobre 6 sitios de la plataforma continental afuera de la Península de Baja California entre los paralelos 26° y 24° N. Todas las muestras fueron secadas al sol y homogenizadas con molino antes de la extracción de lípidos. El contenido de astaxantina se midió también en cada localidad. Los esteres metílicos del total de ácidos grasos fueron obtenidos y analizados por cromatografía de gases con detección por ionizanon de flama. El contenido de lípidos y astaxantina varió significativamente de menor a mayor profundidad y ambos componentes mostraron correlaciones significativas (p < 0.05). Los ácidos grasos C16 : 0, C16 : 1, C18 : 0, C18 : 1, C18 : 2n-6, C18 : 3n-3, C20 : 4n-6, C20 : 5n-3 y C22 : 6n-3 fueron identificados y cuantificados. El ácido graso más abundante fue C20 : 5n-3 que varió de 8.3 a 21.06 g/100 g de los lípidos totales, seguido de C16 : 0 (3.4-14.1 g/100 g LT) y el C20 : 4n-6 (1.42-7.43). Los ácidos grasos con la menor variación estadística entre localidades fueron C18 : 3n-3 y C20 : 5n-3. Los ácidos grasos de las distintas localidades se agruparon en una estructura de clinal latitudinal, sugiriendo que la langostilla es un buen indicador de la existencia de áreas de distinta productividad y calidad de alimento.
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Decapoda Brachyura from Monte Argentario (Mediterranean Sea, central Tyrrhenian)
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The paper is an annotated check list of the Decapoda Brachyura hitherto found in the Tyrrhenian Sea, off Monte Argentario at the southern end of the Tuscan Archipelago (Italy). The data were collected in the period 1998-2002 in the framework of a long-term programme to compile a checklist of all decapod taxa. Samples were collected on different substrates, at different depths (0-300 m) and with different collecting methods. Some of the species found are of biogeographical or ecological interest. These include Maja goltziana Oliveira, 1888, Paractea monodi Guinot, 1969, and Paragalene longicrura (Nardo, 1869). Moreover, the record of a specimen of Calappa sp. is discussed.
Viene qui riportata la lista e relative osservazioni dei decapodi brachiuri finora rinvenuti nelle acque del Monte Argentario, al confine meridionale dell' Arcipelago Toscano (Italia). I dati sono stati raccolti dal 1998 al 2002 nell'ambito di un programma il cui obiettivo è quello di redigere una check-list dei crostacei decapodi. I campioni sono stati raccolti su substrati di varia natura, a diverse profondità (0-300 m) e utilizzando differenti tecniche di pesca. Alcune specie raccolte sono risultate molto interessanti dal punto di vista biogeografico o ecologico. Fra queste Maja goltziana Oliveira, 1888, Paractea monodi Guinot, 1969 e Paragalene longicrura (Nardo, 1869). Viene inoltre discusso il ritrovamento di un individuo di Calappa sp.
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New morphological information on the parasitic copepods Caligus epinepheli Yamaguti, 1936 and Caligus rotundigenitalis Yu, 1933 (Copepoda, Caligidae) from South Africa
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Caligus epinepheli were collected from De Hoop Nature Reserve along the south coast and from Lake St Lucia along the east coast of South Africa. Caligus rotundigenitalis were collected from Lake St Lucia. Two females, one male, and one chalimus of C. epinepheli were removed from the gill chambers of Diplodus sargus capensis and Rhabdosargus holubi. Only two females of C. rotundigenitalis were removed from inside the operculum of Rhabdosargus holubi. Both species represent new host and distribution records for South Africa. The morphological features of these two species were studied with the aid of scanning electron microscopy. Numerous small setae were observed on the marginal membrane as well as on the dorsal shield of C. epinepheli, probably with a sensory function. Another interesting feature is the long seta near the base of the maxillule, bearing spinules on both margins. All other known Caligus species studied so far have a smooth, long basal seta of the maxillule. In C. rotundigenitalis, the first four spines on the second segment of the exopod of leg 4 are covered with spinules.
Caligus epinepheli a été collecté dans la réserve naturelle De Hoop le long de la côte sud et dans le lac St Lucia le long de la côte est d'Afrique du Sud. Caligus rotundigenitalis a été trouvé dans le lac St Lucia. Deux femelles, un mâle et un chalimus de C. epinepheli ont été prélevés dans les chambres branchiales de Diplodus sargus capensis et de Rhabdosargus holubi. Seules, deux femelles de C. rotundigenitalis ont été collectées à l'intérieur de l'opercule de Rhabdosargus holubi. Les deux espèces représentent de nouveaux signalements d'hôte et de répartition pour l'Afrique du Sud. Les caractéristiques morphologiques de ces deux espèces ont été étudiées en microscopie électronique à balayage. De nombreuses petites soies ont été observées sur la membrane marginale et sur le "bouclier" dorsal de C. epinepheli, ayant probablement une fonction sensorielle. Un autre trait intéressant est la longue soie basale de la maxillule portant des spinules sur les deux bords. Toutes les autres espèces connues de Caligus étudiées jusqu'à présent ont une longue soie basale lisse à la maxillule. Chez C. rotundigenitalis, les quatre premières épines du second segment de l'exopodite de la quatrième patte sont recouvertes de spinules.
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Copépodes harpacticoïdes stygobies de France. 6. Description d'un nouveau représentant du genre Parastenocaris Kessler, 1913
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Description of a new stygobiont harpacticoid, Parastenocaris aberrans sp. n. from France (Atlantic part of the Pyrenees region). The new species belongs to the fontinalis group and is morphologically similar to Parastenocaris fontinalis and P. meridionalis. The new species differs from these two taxa by the structure of the endopod of P2-P4 and P5.
Description d'un nouvel harpacticoïde stygobie, Parastenocaris aberrans sp. n., des eaux souterraines de France (Pyrénées Atlantiques). La nouvelle espèce appartient au group fontinalis et, par sa morphologie, est très proche des espèces Parastenocaris fontinalis et P. meridionalis. La nouvelle espèce s'en distingue par la structure des endopodites de P2-P4 et de P5.
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The effect of temperature on the reproductive cycle of the tropical barnacle, Chthamalus malayensis Pilsbry (Cirripedia)
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The effect of temperature on breeding activity and moulting of the tropical barnacle, Chthamalus malayensis was studied under rearing conditions in the laboratory. Both breeding activity and moulting frequency were influenced by temperature. Temperature seems to be the main external factor regulating both breeding and moulting in C. malayensis in Hong Kong. The temperature above which breeding begins in C. malayensis agrees well with the natural breeding season.
L'effet de la température sur l'activité de reproduction et la mue du cirripède tropical, Chthamalus malayensis a été étudié dans des conditions d'élevage au laboratoire. L'activité reproductive et la fréquence de mue étaient influencées toutes deux par la température. La température semble être le principal facteur externe régulant à la fois la ponte et la mue chez C. malayensis à Hong Kong. La température à laquelle la reproduction commence chez C. malayensis s'accorde bien avec la saison naturelle de reproduction.
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Is the glucose concentration in the haemolymph a suitable indicator of circadian rhythmicity in Nephrops norvegicus (Decapoda, Nephropidae)?
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The haemolymph glucose concentration shows marked fluctuations over a 24-hour cycle in several decapods. In the present study, the influence of the diel light cycle as a modulator of glucose concentration was evaluated in the haemolymph of Nephrops norvegicus in the northwestern Mediterranean. Haemolymph samples were collected from animals caught by bottom trawls at two depths, 100 m and 400 m, during two different seasons, October and June. A time series analysis showed the absence of a rhythmic pattern in the glucose concentration at either depth and in either season. Knowing that fishing stress increases haemolymph glucose concentration, laboratory experiments were also planned under controlled conditions, under different photoperiod regimes (day-night: 12-12, 18-6, 6-18). Again, no rhythmic fluctuations in glucose concentration were detected. Field glucose concentrations were higher than those determined in laboratory experiments (t-test, p ≤ 0.05), indicating a reference value of the stress for animals caught by trawling nets. Therefore, the absence of rhythmicity in both field survey and laboratory experiments suggests that this physiological variable is not a suitable indicator of the circadian rhythmicity in animals dwelling at a depth greater than 100 m. We propose that rhythms in locomotor and emergence behaviour and their influence on the underlying physiology may explain the glucose arrhythmicity in this species.
La concentración de glucosa en hemolinfa muestra marcadas fluctuaciones diarias en varios decápodos. En este estudio se evalúa la influencia del ciclo luminoso diario sobre la concentración de glucosa en la hemolinfa de Nephrops norvegicus del Mediterráneo oeste. La hemolinfa fue extraída de ejemplares capturados por artes de arrastre en profundidades de 100 y 400 m, durante Octubre y Junio. El análisis de la serie temporal de datos no mostró ningún patrón rítmico en la concentración de glucosa, ni por profundidad ni por época del año. Asumiendo que el efecto de estrés de pesca incrementa la concentración de glucosa, se realizaron también extracciones en condiciones controladas de laboratorio bajo distinto fotoperiodo (día-noche: 12-12, 18-6, 6-18). Tampoco se detectaron variaciones rítmicas. Los resultados muestran que las concentraciones de glucosa de los animales procedentes del campo fue superior a la de los animales de laboratorio (t-test, p ≤ 0.05) indicando un valor de referencia de estrés para animales procedentes de la pesca. La ausencia general de variaciones en la concentración de glucosa en la sangre, tanto de los animales procedentes del campo como los estudiados en laboratorio sugieren que esta variable fisiológica no es un buen detector de la ritmicidad diaria en Nephrops. Se discute el papel que el comportamiento locomotor y de emergencia de las madrigueras en Nephrops pueda tener en la arritmicidad diaria de glucosa en esta especie.
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The effect of rearing density on body size and weight increase in Streptocephalus torvicornis (Anostraca)
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To obtain information necessary for selection and mass-production of new species to be used for aquacultural purposes, we studied the effect of rearing density on the growth of the anostracan, Streptocephalus torvicornis from hatching to the juvenile stage. The newly hatched nauplii were reared at three densities (50 ind. l−1, 200 ind. l−1, and 500 ind. l−1) with 6 parallel tests per density. The head-anus length, wet weight, and dry weight were measured at four stages of development (at hatching, at 36 and 86 hours after hatching, and by the end of metamorphosis). Calculation of the time required to reach the juvenile stage at each rearing density showed that there was no effect of rearing density on growth at relatively low densities (50 and 200 ind. l− 1), whereas growth rate, length, and weight of the juveniles decreased significantly at a high rearing density (500 ind. l−1). Moreover, the time required for metamorphosis increased at high densities. There were no significant differences in the length-weight regression lines at the three densities and their slope was always less than 3, indicating that growth was due more to an increase in length than in weight.
Allo scopo di selezionare e produrre in massa nuove specie per l'uso in acquacoltura è stato studiato l'effetto della densità di allevamento sulla crescita dell'anostraco Streptocephalus torvicornis dalla schiusa alla trasformazione in juveneis. I nauplii appena schiusi sono stati fatti crescere a tre differenti densità (50 ind. l−1 , 200 ind. l−1 e 500 ind. l−1) preparando 6 test paralleli per ciascuna densità' ed in quattro momenti della crescita (alla schiusa, dopo 36 e 86 ore dalla nascita ed al termine della metamorfosi) sono state misurate la lunghezza capo-ano, il peso secco e il peso umido. Per ciascuna densità di allevamento è inoltre stato calcolato il tempo impiegato per raggiungere lo stadio di juveneis. I risultati ottenuti evidenziano che, mentre a densità relativamente basse (50 e 200 ind. l−1) non si ha alcuna influenza della densità sulla crescita, quando le densità di allevamento divengono elevate (500 ind. l−1) i tassi di crescita diminuiscono significativamente così come la taglia ed il peso raggiunti dagli juvenes. Ad alte densità, inoltre, il tempo impiegato per la metamorfosi aumenta sensibilmente. Per quanto concerne invece la relazione tra lunghezza e peso, non sono state rilevate differenze significative nelle rette di regressione calcolate alle tre densità in studio ed in tutti i casi la pendenza delle rette è risultata inferiore a 3, indicando una crescita primariamente in termini di lunghezza, e meno in termini di peso.
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