نتایج جستجو برای: crustacea
تعداد نتایج: 9555 فیلتر نتایج به سال:
A replacement name is proposed for genus Dayus Gerken, 2001 (Crustacea: Peracarida: Cumacea), preoccupied by Dayus Mahmood, 1967 (Insecta: Hemiptera: Cicadellidae). The following changes are proposed: Jennidayus new replacement name = Dayus Gerken, 2001 (nec Mahmood 1967); Jennidayus pharocheradus (Gerken, 2001), comb. n. = Dayus pharocheradus Gerken, 2001; Jennidayus acanthus (Gerken, 2001), c...
Fresh water prawns, Macrobrachium lamarrei and Macrobrachium dayanum (Crustacea-Decapoda) were subjected to static bioassay tests to ascertain the LC50 values of copper sulphate. The 24, 48, 72 and 96 hr LC50 values of copper sulphate for M. lamarrei were 0.38, 0.361, 0.343 and 0.300 mg/l and for M. dayanum were 1.634, 0.988, 0.532 and 0.418 mg/l respectively. Behavioral responses and LC50 valu...
Mantis shrimps (Crustacea: Stomatopoda) are rather rare in the fossil record. Nineteen species have been assigned to Squillidae, of which 12 species have been recorded from the Miocene. We describe herein a squillid, Squilla taulinanus n. sp., from the Miocene of Taulignan, south-eastern France. The exceptionally well-preserved specimen is remarkable in apparently having abdominal somites 5–6 c...
In most, possibly all, Crustacea the heart beat is neurogenic. Each beat is initiated by a burst of impulses from a small group of neurones whose cell bodies lie grouped in the ganglionic nerve trunk (g.n.t.) in the heart wall and whose axons run to the heart muscle. Many attempts have been made by electrophysiologists to discover how these neurones are integrated to fire rhythmic bursts (for e...
> Abstract 150 years after Darwin’s ‘Origin of Species’ and 100 years after W.T. Calman’s infl uential treatment on crustacean morphology and classifi cation, crustacean phylogenetics remains an active, exciting and controversial fi eld of research. An international symposium held from 7th–11th October 2008 at the University of Rostock attempted to summarize the latest developments. Molecular e...
Polarisation sensitivity (PS) - the ability to detect the orientation of polarised light - occurs in a wide variety of invertebrates [1] [2] and vertebrates [3] [4] [5], many of which are marine species [1]. Of these, the crustacea are particularly well documented in terms of their structural [6] and neural [7] [8] adaptations for PS. The few behavioural studies conducted on crustaceans demonst...
The present study provides a characterization of water quality and plankton samples in earthen fish pond in Rajshahi, Bangladesh. Sampling was done over a period of six months, running from October, 2004 through March, 2005. All the water quality parameters were within the optimal ranges for plankton productivity. Temperatures varied from 19.75 to 27.25 degrees C; transparency, 24.75-29.50 cm; ...
Seasonal dynamics of plankton, water temperature, conductivity, pH, total alkalinity, phosphatephosphorus and nitrate-nitrogen of Burulia beel were measured. These values were within the acceptable ranges. In the present study, water temperature, pH, Nitrate-nitrogen, Phosphate-phosphorus were found to range from 13.50 to 30.50°C, 6.21 to 7.33, 1.36 to 2.85 mg/l and 0.07 to 0.71 mg/l, respectiv...
The Remipedia are enigmatic crustaceans from anchialine cave systems, first described only 30 years ago, whose phylogenetic affinities are as yet unresolved. Here we report the sequence of hemocyanin from Speleonectes tulumensis Yager, 1987 (Remipedia, Speleonectidae). This is the first proof of the presence of this type of respiratory protein in a crustacean taxon other than Malacostraca. Spel...
Atyid freshwater shrimps are globally distributed and form an important part of freshwater ecosystems, particularly in the tropics and subtropics. Despite their widespread distribution and ecological importance, their phylogenetic relationships are largely unresolved. Here we present the first comprehensive molecular phylogeny of the Atyidae investigating the evolutionary relationships among 32...
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