Carnivorous Genus Research Articles

The genus Pinguicula L. (Lentibulariaceae): an overview

The carnivorous genus Pinguicula, which currently consists of about 74 species, is part of the Lentibulariaceae family. All members are active animal and plant organ trappers. The leaves are sticky and constitute flypaper—type traps capable of slow motions. The present review focusses on several aspects of the research activities conducted on this genus. These include the study of its evolution, carnivory, trapping and digestion mechanisms, with a special emphasis on the key role played by the mucilage, its ecology and its pharmacological and culinary utilization. This review also stresses the need for a global taxonomic revision of the genus. Finally, it aims to generate greater interest on these very fascinating plants which are in urgent need of protection.

Relationships between catch and effort in Fijian multispecies reef fisheries subject to different levels of exploitation

Abstract The catch‐per‐unit‐effort (CPUE) and value‐of‐catch‐per‐unit‐effort (VPUE) of reef‐associated fish species from six Fijian native fishing grounds (qoliqoli) subject to different fishing intensities were determined using records of fishing activity from a voluntary logbook scheme. Line and spear fishing techniques were used for more than half the total fishing time (h person‐1 d‐1) in all qoliqoli, and yet the favoured technique in a given qoliqoli was frequently less efficient (lower CPUE) than other techniques. The popularity of relatively ineffective fishing methods implies that fishermen did not always attempt to maximize their catch rates. To compare fishing effort in different qoliqoli, all effort was rescaled on the basis of its recorded efficiency (measured as multispecies CPUE) and expressed as hours equivalent to boat‐based spear fishing over coral by day to catch fish for sale. Total fishing intensity in the six qoliqoli ranged from 72 to 4310 h km‐2 reef year‐1. The relationship between catch and effort was linear at all fishing intensities, suggesting that the qoliqoli were all fished on a sustainable basis. Furthermore, whilst there was a significant difference in CPUE and VPUE between the one or two qoliqoli with lowest fishing intensity and all the others, there were no significant differences between these other qoliqoli in terms of the VPUE of the saleable multispecies boat catch or the CPUE of species from piscivorous and carnivorous genera (Epinephelus, Lethrinus and Plectropomus) which the fishermen prefer to catch.

Dicentroptiluma new genus of mayflies (Baetidae, Ephemeroptera) from Africa

A new genus of baetid mayflies is described, the adults closely related to the carnivorous genus Centroptiloides but the nymphs with mandibles of the ancestral grinding type. Two species formerly included in Afroptilum are transferred to Dicentroptilum, A. decipiens and A. spinulosum. A new species from West Africa is described here.

Invertebrate zooplankton predator composition and diversity in tropical lentic waters

Invertebrate zooplankton predators are generally less diverse in average species numbers in tropical than in temperate lakes and reservoirs. Predatory Copepoda which comprise the majority of limnetic predators are particularly low in species numbers in the tropics. Predatory Cladocera are confined to the North Temperate zone. Chaoborus appears to be cosmopolitan. Among Rotifera, only the cosmopolitan predator Asplanchna occurs in tropical waters while the other common limnetic carnivorous genus Ploesoma is restricted to higher latitudes. Hydracarina, and insects besides Chaoborus, are generally restricted to the littoral and appear to be more diverse in the tropics. Lakes Awasa and Zwai, Ethiopia, are almost devoid of predators in the limnetic, which is invaded by a littoral chydorid Alona diaphana. Low diversity of lake types and low production of tropical zooplankton could restrict predator diversity too. Very low diversity of invertebrate predators in the limnetic and higher diversity in the littoral may characterize tropical lakes in contrast to temperate lakes, which have more invertebrate predators in the limnetic and perhaps relatively less in the littoral. Tropical zooplankton in freshwaters, appears to be a very immature community. Hence opportunistic species can readily invade the limnetic and even dominate in isolated situations as has been shown for Alona davidi, Hydracarina and some other unconventional forms.

The Digestive Glands of Pinguicula: Structure and Cytochemistry

The digestive glands of the carnivorous genus Pinguicula have three functional compartments, (a) a basal reservoir cell, (b) an intervening cell of endodermal character and (c) a group of secretory head cells. The gland complex is derived from a single epidermal initial. The reservoir cell, which is rich in Cl− ions, is highly turgid before discharge; it is linked by plasmodesmata to the surrounding epidermal cells, and is ensheathed by a pectin-rich inner wall layer. The endodermal cell is bounded by a Casparian strip to which the plasmalemma is tightly attached; it contains abundant storage lipid and numerous mitochondria. The head cells of the developing gland have labyrinthine radial walls of the transfer-cell type, the ingrowths being composed of pectic polysaccharides. The bounding cuticle is discontinuous, although lacking well-formed pores. Mitochondria are numerous, with well-developed cristae; the plastids are large and ramifying, and invested by ribosomal endoplasmic reticulum. Dictyosomes are sparse, and where they occur, are associated with coated vesicles. Ribosomal endoplasmic reticulum is moderately abundant in the head cells, and so also are free ribosomes. Optical and electron microscopic localization methods indicate that the digestive enzymes are synthesized in the head cells and transferred both into the vacuoles and into the walls. There is no evidence of a granulocrine mode of secretion, and the transfer seems to be initially by direct perfusion through the plasmalemma. During the final phase of maturation of the head cells they suffer a form of autolysis, vacuoles, cytoplasm and wall becoming confluent as all of the membranes of the cell undergo dissolution. The gland head is thus, in effect, simply a sac of enzymes at the time of the ultimate discharge.

XXXII.—Description of a second species of the carnivorous genus Nandinia, from Southern Nyassaland

XXXII.—<i>Description of a second species of the carnivorous genus</i> Nandinia, <i>from Southern Nyassaland</i>

Some Recent Restorations of Dinosaurs

IF palæontologists are apt to be discouraged by the apparent hopelessness of ever arriving at a satisfactory conclusion as to the structure and affinities of some of the fossil vertebrates with which they have to deal, they ought assuredly to take fresh confidence from the marvellous advance which has taken place of late years in our knowledge of the organisation of those huge extinct reptiles commonly known as Dinosaurs. It was, indeed, as far back as 1824 that the carnivorous genus Megalosaurus was first made known to us by Buckland, from specimens obtained in the Great Oolite of Oxford, while the following year saw the first announcement by Mantell of the now well-known Iguanodon from the Sussex Wealden. These early pioneers in this branch of palæontology necessarily had, however, but a faint conception of the real structure, and still less of the morphological importance of the group of reptiles whose former existence they were the first to reveal. It was long, indeed (in spite of the efforts of anatomists like Cuvier, Owen, and Huxley), before the riddle of the structure of the pelvis of the Iguanodon was solved, the final solution being given by Mr. J. W. Hulke in a paper read before the Geological Society on June 9, 1875, and published in the following year. The appearance of this paper may be said, indeed, to mark the commencement of the epoch of rapid advance in our knowledge of Dinosaurs, for only two years afterwards (1878) was issued the first of Prof. O. C. Marsh's important series of memoirs on the American Jurassic Dinosaurs, from which it appears that the true nature of the Iguanodont pelvis had been independently discovered in America. About the same time that the first of the American palæontologist's memoirs saw the light the scientific world was startled by Monsieur E. Dupont's announcement of the discovery of numerous entire skeletons of Iguanodons in fissures of the Belgian coal-fields. And this unexpected and fortuitous discovery enabled Monsieur L. Dollo to publish in April, 1883, the completely restored skeleton of one of these monsters in its natural attitude.