Large Claw Research Articles

Plant Life in the Age of Dinosaurs

Why plants? – Why include plants in a course on dinosaurs? They don't move, lack large teeth and sharp claws, and are non-sentient. The average student (who can spell Deinonychus correctly) hasn't a clue to the genera of even the most common plants. However, without plants, dinosaurs (or any other heterotroph) would not exist. Plants are the basis for global life, trapping the sun's energy in a form useful to consumers. Thus, the photosynthetic efficiency, palatability, and digestibility of plants define the total energy in the system available for use by consumers – and therefore the total biomass of consumers. Additionally, the morphology of individual plants determines the “packages” of food available to herbivores, and in the aggregate, the three-dimensional environment in which the herbivores and their carnivores live.

Baryonyx, a remarkable new theropod dinosaur.

An extremely large claw bone, some 30 cm long, was found in Wealden (Lower Cretaceous) deposits in a Surrey claypit in January 1983. This led to the discovery the following month of the well-preserved skeleton of a new large theropod dinosaur. Only one other theropod specimen comprising more than a few bones had ever been found in Britain, and that discovery was more than a century ago. Indeed, no large theropod, reasonably complete, had previously been discovered in Lower Cretaceous rocks anywhere in the world. Our study so far suggests that the Surrey dinosaur was a typical large theropod in certain respects, resembling, for example Allosaurus. In several other respects, however, it differs sufficiently from all known dinosaurs to merit designation as the representative of a new species, genus and family.

The adhesive organ of the blowfly, Calliphora vomitoria: a functional approach (Diptera: Calliphoridae)

The external morphology of the terminal region of the fifth tarsal segment of the blowfly, Calliphora vomitoria (L.) has been studied using light and scanning electron microscopy (S.E.M.). The pulvilli, with their numerous tenent hairs of spatulate form projecting from the ventral surface, are responsible for adhesion to smooth surfaces. The two large claws are believed to be important in clinging to irregularities in surfaces. Two footplates, possibly sensory organs, lie in close association with the base of the large ventral seta, the empodium. Blowflies release a non‐volatile lipid secretion on to the spatulate ends of the tenent hairs and this secretion is essential to the adhesion process on smooth surfaces. The force of adhesion has been measured for tethered blowflies on glass using both vertical and lateral pulls; lateral pulls gave much greater forces. It is concluded that surface tension of the lipid secretion under tenent hairs is sufficient to enable successful adhesion to smooth surfaces by blowflies.

Milk Droplet Impacts During Induced Vacuum Fluctuations: Influence of Claw and Other Characteristics

Severity of milk droplet impacts against teat ends as a result of abrupt loss of milk line vacuum was measured with impact sensitive transducers placed in milking machine liners. Impacts were generally more severe with low rather than high milk lines and with nonvented rather than vented claws. However, impacts were more severe with high than with low milk lines when measured during the low-flow stage of milking. Style of claw did not influence severity of impacts. Measurement of droplet movement from long milk tubes into claws showed that a large claw intercepted a greater percentage of milk droplets on their way from long milk tubes to teat end than did a small or a medium claw, and also reduced vacuum fluctuation in the short milk tube relative to the small or medium claw. However, neither of these factors led to significant reduction of teat-end impacts when large claws were used. An unvented claw with a high milk line reduced milk flow rate and yield within milking. The smallest, lightest claw gave lowest yield within milking.

On the biological basis of human laterality: I. Evidence for a maturational left–right gradient

AbstractIn this paper, we consider human handedness and cerebral lateralization in a general biological context, and attempt to arrive at some conclusions common to the growth of human laterality and of other structural asymmetries. We suggest that many asymmetries appear to be under the influence of a left-right maturational gradient, which often seems to favor earlier or more rapid development on the left than on the right. If the leading side is damaged or restricted, this gradient may be reversed so that growth occurs with the opposite polarity. A mechanism of this sort appears to underlie the phenomenon ofsitus inversus viscerum et cordis, and the same principle may help explain the equipotentiality of the two sides of the human brain with respect to the representation of language in the early years of life. However we must also suppose that the leading side normally exerts an inhibitory influence on the lagging side, for otherwise one would expect language ultimately to develop in both halves of the brain. Examples of an inhibitory influence of this kind can also be found in other biological asymmetries; for instance, in the crabAlpheus heterochelis, one claw is normally greatly enlarged relative to the other, but if the larger claw is removed the smaller one is apparently released from its inhibitory influence and grows larger.This last example is particularly interesting because it suggests a mechanism comparable to that proposed by Annett to account for the distribution of handedness in the human population. She argued, in effect, that there is a “right shift” factor among the majority of the population, but that among a minority who lack this factor handedness is determined at random. If it is supposed that cerebral lateralization is also determined at random among this recessive minority, the model can be extended to provide a reasonable fit to the data on the correlation between handedness and cerebral lateralization. However this genetic model (or any other) still fails to account for the near-binomial distribution of handedness among twins and among nontwin siblings. We suggest that right-handedness and leftcerebral dominance for language are manifestations of an underlying gradient which is probably coded in the cytoplasm rather than in the genes. We must leave open the question as to whether departures from this pattern are due to a recessive gene which effectively cancels the asymmetry to environmental influences, or to both genetic and cytoplasmic factors.

Development of Asymmetry in the Fiddler Crab Uca Cumulanta Crane, 1943 (Decapoda Brachyura)

The development of asymmetry of male claws was studied in a species of Venezuelan fiddler crabs, Uca cumulanta (Crane). Adult right-handed males (dextrals) of this species were found to regenerate large right claws in place of selectively removed right large claws and left-handed males (sinistrals) were found to regenerate large left claws in place of left large claws; the remaining small claws were never enlarged after the removal of the original large claws. In a few symmetrical stage crabs having two small claws, right claws were enlarged when left small claws were removed and left claws were enlarged when right small claws were removed. No reversal occurred in the direction of differentiation even after two to three molts so that selective removal of small claws seems to induce a permanent asymmetry in these symmetrical stage crabs.

Sauropod habits and habitats

Sauropod natural history has been widely a discussed and sometimes controversial topic. All amphibious theories of sauropod behavior from Cope and Marsh onward may have been inspired by Owen. Sauropod narial morphology might indicate either aquatic or terrestrial habits, and some sauropods may have had a complex narial structure, possibly a proboscis. Sauropods were vegetarians, but the specific diet of Diplodocus is unclear. Long necks could have been used for browsing in trees, or long streambanks, or under water. Sauropod axial appendicular modifications point to primarily terrestrial behavior. Sauropods may have had bird-like lung system. Sauropods sometimes dragged their tails on the ground and may have used for defense. The deep thorax of sauropods is an adaptation to problems of terrestrial weight-bearing. Sauropod foot and limb structure is generally compartable to elephants, except in lack of joint ossification and development of large claws. Sauropods sometimes reared up on their hind limbs, and they definitely entered streams at least sometimes, but sedimentologic evidence does not support immersion in deep lakes as sauropods are frequently pictured. On the problem of terrestrial versus amphibious habits, most sauropod anatomy is equivocal, but where firm morphologic interpretations are possible, they usually point to terrestrial behavior.

Aspects of the aggressive and sexual behaviour ofalpheus heterochaelissay

Alpheus heterochaelis were collected near Beaufort, N.C. Males have a greater ratio of claw length/total body length than females. In field‐caught pairs, females tend to have longer bodies and males tend to have larger claws. In Y‐maze tests, males tend to seek females on the basis of chemical cues. The intensity of the sound produced by the large claw is positively correlated with claw size. Thus, stimulus intensity offers potential cues to the size of an opponent. Cine studies reveal that the large claw closes within 1.67–5.00 msec during snap production. An ensuing water jet travels at ca. 1.5–4.0 mm/sec and is directed toward an opponent. Size restrictions found in paired shrimp are hypothesized to result from an agonistic “balance”; established during initial contacts made prior to sex determination and pairing. The male's larger claw size/body size is explained by selection pressure favouring his mating with larger females who can produce more offspring.

Electrophysiological investigation of GABA-mediated inhibition at the hermit crab neuromuscular junction.

1. The inhibitory neuromuscular junction of the abductor muscle of the large claw of the hermit crab (Eupagurus bernhardus) was investigated using electrophysiological intracellular techniques in order to elucidate further the relative contributions of the pre- and post-synaptic mechanisms of action of GABA and of neural inhibition.2. The electrical constants of the post-synaptic membrane, calculated using the equations for a ;short cable' model, were characteristic of a poorly developed electrical excitability; the specific membrane resistance was usually < 1000 Omega cm(2) and the specific membrane capacitance was > 40 muF/cm(2).3. Stimulation of the excitatory axon to the abductor muscle of the large claw at a frequency of 20 Hz evoked highly facilitating excitatory junction potentials (e.j.p.s); stimulation of the inhibitory axon (60-220 Hz) during the excitatory train elicited inhibition which was manifest as an attenuation of the e.j.p.s.4. The addition of gamma-aminobutyric acid (GABA) to the bathing solution produced a dose-dependent reduction of e.j.p. amplitude and membrane resistance. The inhibitory effect of concentrations (5 x 10(-5) and 1 x 10(-4)M) which caused a 40-75% e.j.p. attenuation could largely be accounted for by a post-synaptic action on membrane conductance.5. Experiments with picrotoxin suggest that presynaptic inhibitory mechanisms have an important role in neurally evoked inhibition.6. Picrotoxin (1-5 x 10(-5)M) effectively blocked neural inhibition and the actions of GABA in this preparation, whereas bicuculline proved to be considerably less potent and therefore less useful as a physiological tool for studying GABA-mediated inhibition in crustacea.

A study of Paridae community in Japan

1. In the sympatric congeneric tits (Paridae and Aegithalidae), some comparative studies of the methods in the use of bills and the structure of the among the bill species were made and the ecological separation, as related with the spaces for each species were discussed. The vegetation of the studied area is a mixed deciduous woods in central Japan, as detailed by T. Nakamura (1970, 1975).2. The species features in the morphological characters shown by body length, wing length, tail length, tarsus length, toe length, bill length, bill width and bill depth are as follows:Long-tailed Tit (Aegithalos caudatus) has a smaller body but a longer tail, wing, and tarsus in relative length than Parus species. The bill of Long-tailed Tit is shorter and has a more curved shape than Parus species.In Parus, the relative length of tail is smaller than that of the Long-tailed Tit and the relative length of toes is greater than that of Long-tailed Tit. The shape of the bill in Parus is more similar to the simple cone than that of Long-tailed Tit. Great Tit (Parus major) has larger toes and their bill is not specialized as compared with other three species of Parus. Coal Tit (Parus ater) has a smaller body but has a relatively long wing than other Parus species. The shape of the bill of Coal Tit is thin and pointed. Willow Tit (Parus montanus) has the toes with large claws, and the length of the hind and the midde toes is almost the same. The bill of Willow Tit has a larger relative depth (ratio of depth to width or length) than the other three species of Parus. Varried Tit (Parus varius) has a larger body length and a pointed bill. The shape of the bill of this species is flattened at the tip like a flat chisel.3. The species features as represented the methods of using the bill in attacking the preys and picking seeds are as follows:Long-tailed Tit often takes the hunging posture on a twig of larch and deciduous trees, and quick picking and pecking are the most simple methods of using the bill. However, Parus species have more varied methods in the use of the bill and more varied attacking sites than Long-tailed Tit. Especially, it is characteristic of Parus species that they have methods of processing by their bill on the sites or objects where they suppose available food existed and they often hammer them and remove the food. Great Tit removes a piece of bark on the branch or the trunk or a fallen leaf on the ground. Coal Tits destroy the buds or a lump of dead leaves clung to twigs by bitting or thrusting by their bill. Willow Tit digs up dead parts in trees, often while hunging under the branches or twigs. Varried Tit holds seeds, acorns, insect galls or other ball like matters on perch by their toes and crushes them pecking by the bill.4. The methods in the use of the bill well correspond with the morphological characteristics of the bill in each species. Due to the large differences in the use of the bill, in the structure of the bill and in the sites for attacking preys between Long-tailed Tit and Parus species, their coexistence will be possible in various locations in Japan. I think that the ecological differences between Long-tailed Tit and Parus species are larger than such interspecific differences within genus Parus, such as the differences in the shape of bills. These congeneric interspecific differences may not allow the coexistance of species within Parus completely but only uncompletely. Therefore, the species compositions of Parus in sympatric ranges vary from site to site.5. The methods in the use of bills well correspond with the micro-structure in a microhabitas.

DDT Residues Absorbed from Organic Detritus by Fiddler Crabs

DDT and its metabolites accumulate in organic plant detritus estuaries and may persist there for many years. The residues appear to be most abundantly associated with particulates having diameters from 250 to 1000 microns. Detritus particles of this size are ingested by many organisms, sociated DDT residues may enter diverse food chains. Fiddler crabs Uca were fed natural detritus containing DDT residues (10 parts per million) an 11-day experiment and showed grossly modified behavior associated threefold increase in concentration of DDT residues in the muscle of the large claw.

Discussion

Professor T. B arnard said that some of the burrows and infillings of burrows shown by Dr Bromley appeared to be funnel-shaped or irregularly shaped, and to branch; these characters were unusual for burrowing Crustacea. Many burrowing arthropods tended to burrow backwards and the burrow then filled in after the animal had disappeared from sight. One of the figures shown by Dr Bromley in his lecture suggested that an arthropod with one large claw (like a fiddler crab) was moving forward in the burrow and digging in this manner; this would be unusual for any arthropod of this type. The speaker would therefore like to ask the author whether he knew of any Recent arthropod which made a funnel-shaped or ramified boring or burrow and which moved backwards and forwards within a burrow when made. He also wondered how the arthropod managed to stabilize the walls of the burrow in soft sediment, since arthropods did not secrete mucus. The numerous burrows, and bioturbated chalk occurrences spread over a large area, would suggest population explosions at many levels within the Chalk. It was perhaps difficult to imagine a large number of arthropods occurring without leaving some trace of their hard parts, for claws and appendages were extremely rare within the Chalk. He would therefore suggest that much of the bioturbation and burrowing was of annelid and not arthropod origin. The bathymetric ranges of modern arthropods was large, going down to depths of 2000m or more; however, many of these deep-water living forms

The differentiation of prospective thigh mesoderm grafted beneath the apical ectodermal ridge of the wing bud in the chick embryo

Ectoderm-free isolates of prospective thigh mesoderm from chick embryos of stages 17 to 27 were grafted subjacent to the apical ectodermal ridge of the wing bud of host embryos in stages 18 to 23. Grafts from donor embryos of stages 17 to 19 developed terminally on the wing in a high percentage of the cases, forming typical foot parts, covered with warty and overlapping scales and armed with large claws. Foot parts were found less frequently when donors of stages 20 to 25 were employed, but in a number of cases thigh feathers were induced at wing levels proximal to the wrist. Among cases in which embryos of stages 26 and 27 provided the graft, leg-specific structures were found in only one of 33 cases (one case showing thigh feathers). These effects of donor age have been correlated with the relationships established between the graft and the apical ectodermal ridge of the wing bud. Densely cellular, pliable tissues from younger donors readily conform to the contours of the mesodermal apex of the wing bud and achieve intimate contact with the apical ridge. It has been suggested that they contribute factors which maintain the ridge in an inductively active configuration and are then induced by it to form terminal leg parts. Prospective thigh tissues from older donors contain considerable intercellular matrix, are less flexible, and are more readily displaced from contact with the apical ridge by encroaching wing mesoderm; thus, foot parts are less frequently formed and sometimes thigh feathers are induced proximally on the wing. Now and again, however, with increasing age, prospective thigh tissues do remain in contact with the apical ridge of ectoderm, but, in these cases, the latter loses its normal configuration and no foot parts are formed. Possibly these grafts are unable to supply factors which are necessary to maintain the inductive activity of the apical ectoderm. These results and their interpretation are discussed with respect to recent reports which suggest a contrary interpretation of the role of the apical ectodermal ridge for the growth of terminal limb parts.

Phosphate in Lobster Nerve.

The nerves of the large claws and walking legs of the lobster {Homarus americanus) with or without the abdominal ganglion chain were carefully dissected into iced mortars. They were ground and analyzed, either at once or after standing for 1/2 to 3 hours in closed vessels in moist oxygen or nitrogen at 23-25°C. In a few cases companion analyses were run on nerves resting or stimulated in oxygen, stimulation being continued with fairly strong induction shocks at 100 per second for half an hour. The method of analysis was essentially that described by Fiske and Subbarow, involving extraction with 10% iced trichloracetic acid, part of the filtrate being used to determine total acid-soluble phosphorus after ashing with sulphuric and nitric acids, the larger portion being neutralized and treated with calcium chloride-calcium hydroxide precipitant. After centrifuging and washing, the inorganic phosphate remained in the precipitate. Phosphagen was determined in the clear solution after reacidification with hydrochloric acid and standing at room temperature for days, according to Meyerhof. Phosphate was finally estimated in each fraction by the Fiske-Subbarow method, using a total volume of 15 cc. and comparing with a phosphate standard of 8.0 mg. % strength. The rate of hydrolysis of the phosphagen compound, as tested with acid for different time intervals, clearly showed it to be of the arginine phosphate rather than the creatin phosphate type, which is in conformity with the difference in muscle phosphagens in vertebrates and crustaceans. The usual controls of the adequacy of separation and determination demonstrated the validity of our procedure.

The Development of Asymmetry in the Fiddler Crab

THE experiments of Przibram ('01, '07, '17) and of others have shown in certain species of decapod crustaceans, in which a larger and a smaller "claw" are normally present, that after the removal of the large claw the smaller claw develops into a large claw. In other species, however, including the fiddler crab (Gelasimus), this renewal does not take place after the removal of the large claw. A new large claw regenerates on the stump of the old one. It was known (Hyman, 1920) that in the earliest stages of the fiddler following the Zoea the two claws (first pair of legs) are equal in size and in shape and are like those of the female or like the small claw of the male. I tried to find out whether, if one claw is removed from young male crabs in these undifferentiated stages, the remaining claw will develop into a large claw. It was necessary first to find at what stage the difference in size of the two claws first appears in the young crabs. Here a new fact of some interest came to light. Collections of young crabs were made at North Falmouth, Massachusetts, on July 10, August 3, September 2 and 15, 1922. Those collected on July 10 were crabs of the preceding summer and will be described later. A iew generation came to land in August and September and those of September 2 and 15 give the results shown in the following table. The crabs fall into three groups: (1) those with unequal claws ("male" and "female" claws, or else juvenile, Fig. 1, c; and Fig. 2, b; and Fig. 3,

Birds of the Bois Fort Indian Reservation and Adjacent Territory in Minnesota

THE BOIS FORT (or Nett Lake) Indian reservation, surrounding the beautiful Nett lake, is the home of the Bois Fort Indians. It covers one whole township and eight fractional townships. Its eastern part is in St. Louis county, the bulk in Koochiching county, covering townships and parts of townships as follows: townships 66 north, ranges 21, 22 and 23 west of the fourth principal meridian in Minnesota; also townships 65 and 64, same ranges as above. The reservation is located 125 miles northwest of Duluth and about 38 miles south of Fort Frances, Ontario. It contains a total of 103,862.73 acres, exclusive of the area of the lake, which comprises about three-fourths of a township. Of this about 56,000 acres are allotted to 718 Indians and 434.64 acres are reserved for agency and school purposes. Of the 47,428.09 acres unallotted, much of it was originally reserved by the government as pine lands, aggregating 9,533.93 acres; the remaining unallotted area was mostly swamp land. In 1909 the last of the pine was sold, and in 1914 practically all of the unallotted land was thrown open for settlement. Of the allotted land, more than one-half of the original allottees are dead. Consequently, something like 30,000 acres of inherited Indian lands will be sold within the next few years. Nett lake is in the east central part of the reservation. As has been stated, it covers about three-fourths of a township. It is in the shape of a giant lobster's hand, with the claws pointing eastward, the larger claw being the north digit. The lake is shallow and has a mud bottom. It is a rice field and a duck pond combined. In summer it looks like a vast wheat field. In

Description of a New Pipilo

Subsp. char. Terminal white spot of outer tail feather considerably shorter (less than one inch) than in megalonyx; claws much longer and heavier than in oregonus; under tail coverts darker than in atratus; rump more or less grayish, upper tail coverts tipped with pale buff. Type. No. 2274, 6, McGregor Collection, Palo Alto, California, April 9, 1898. Chord of wing 3.38; tail 3.75; exposed culmen .55; white tail spot .76; chord of hind claw 46. Collected by T. J. Hoover. Type. No. 882, Y, McGregor Collection, Palo Alto, California, March 3, 1898. Range. San Francisco Bay region. I faix + fero; sickle-bearing, referring to the large hind claw.

Ridgway on the Humming-birds

MR. ROBERT RIDGWAY, curator of the bird department of the U. S. National Museum, has just published (in separate form), in the report of that institution for 1890, his monograph of the Trochili. Coming from such an authority and essaying to deal with such an interesting group, this work will undoubtedly command the attention of ornithologists, and be studied with the care it no doubt merits. It makes its appearance in octavo form, of some 130 pages, being illustrated by 46 full-page plates, and has besides a number of cuts in the text. The plates give us many species of humming-birds and their nests; they being all of the “electro-process” variety, and chiefly copied from Gould's princely work upon the Trochili. As is usually the case, most of the figures given have suffered by the method of reproduction employed, and not being coloured, they offer us, at the best, with but a poor idea of the “living gems” they are supposed to portray. With more or less thoroughness Mr. Ridgway has touched upon the early history and the literature of his subject; upon the geographical distribution of the various species; upon their number, which he makes out to be about 500; upon their natural history in general (treated in various brief sections); and there are descriptions of their external characters and a short note upon a few of their internal ones. It is with the statements made in the latter that I chiefly propose to deal in the present connection, and, aware as I am of our author's knowledge of the literature of what we may call the natural history and classification of the humming-birds, as contra-distinguished from their morphology and affinities, I must confess my surprise at his ignorance of the latter part of his subject. Mr. Ridgway remarks (p. 290) that “the humming-birds possess nothing absolutely peculiar, although certain features, shared by other groups of birds, notably the swifts (Micropodidœ"), are developed to an extreme degree; as, for example, the very high keel to the sternum and consequent excessive development of the pectoral muscles, the short armwing (humerus) and extremely long handwing (manus), and minute feet with relatively large, strongly curved, and sharp claws. The humming birds and swifts further agree in numerous anatomical characters, and there can be no doubt that they are more closely related to each other than are either to any other group of birds. In fact, except in the shape of the bill and structure of the bones of the face, the humming-birds and swifts present no definite differences of osteological structure.” As the present writer has probably published double the number of accurate figures illustrating the entire anatomy of a great many species of humming-birds as compared with any ether worker; and, further, has published correct accounts of the same to the extent exceeding that of any three living avian-morphologists, and those figures and descriptions having been very extensively accepted as correct, perhaps our author will consider me competent to criticize the statement which I have just quoted from his work. Notwithstanding the extensive and painstaking labour I have given to such matters, I reckon it but as little when compared with the opinions given us by Huxley and Kitchen Parker in the same premises.

On some New Macrurous Crustacea from the Kimmeridge Clay of the Sub-Wealden Boring, Sussex, and from Boulogne-sur-Mer

It has always appeared to me to be a point of special interest to geologists to record those forms found in a fossil state which have a considerable vertical range, and yet belong to genera existing at the present day. Among higher groups now living, we find the vertical range exceedingly small; but when we examine the Invertebrata, we meet with such genera as Lingula, Pentacrinus , and Limulus having an extremely high antiquity; but the higher forms of these types follow precisely the same general law, having a much more restricted range in time than the lower and humbler genera. One of the Crustacea about to be described by me belongs to a very interesting group, the family of the Thalassinidæ. Most if not all of the members of this family are fossorial in their habits, burrowing in the sand or mud with great rapidity and remaining concealed in their burrows, save their large claws, which have in many instances been caught and devoured by fishes, or have been cut off by the dredge, whilst the animal itself in its burrow escaped. Of living British representatives we have four genera:— 1. Callianassa , Leach (1 species): C. subterranea , Leach. 2. Gebia , Leach (2 species): G. stellata , Leach; G. deltura , Leach. 3. Axius , Leach (1 species): A. stirhynchus , Leach. 4. Calocaris , Bell (1 species): C. Macandreœ , Bell. Formerly only one fossil species of this remarkable group of burrowing Crustaceans was known, the Callianassa (Pagurus) Faujasii , from the uppermost Chalk of Maestricht, first noticed in an admirable