Limblessness and Correlated Changes in the Girdles of a Comparative Morphological Series of Lizards

1947 ◽  
Vol 38 (3) ◽  
pp. 725 ◽  
Author(s):  
Paul Scott Stokely
Keyword(s):  
Morphological Series

MORPHOLOGICAL SERIES WITHIN THE GENUS PYRROSIA, AND THEIR PHYLOGENETIC INTERPRETATION

1967 ◽  
Vol 45 (5) ◽  
pp. 615-634 ◽  
Author(s):  
B. K. Nayar ◽  
Subhash Chandra
Keyword(s):  
Lateral Branch ◽  
Apical Growth ◽  
Primitive Species ◽  
Lines Of Descent ◽  
Morphological Series

The morphology of 13 species of Pyrrosia from India is described and the different species are arranged in six morphological groups, the Flocculosa, Heteractis, Mannii, Nayariana, Obovata, and Varia groups. It is postulated that P. subfurfuracea is the most primitive species in the genus, and the others are evolved from it: the different lines of descent from P. subfurfuracea are traced.It is concluded that Pyrrosia is more intimately related to Platycerium and Drymoglossum than to any other living fern, and along with them has evolved probably from extinct gleichenioid ancestors. The possible origin of a short-creeping rhizome, bearing leaves on phyllopodia associated with lateral branch buds, from ancestors possessing leaf-bearing vertical branches with arrested apical growth, as found in Stromatopteris, is suggested.

Colour pattern modification by coldshock in Lepidoptera

Development ◽  
1984 ◽  
Vol 81 (1) ◽  
pp. 287-305
Author(s):  
H. Frederik Nijhout
Keyword(s):  
Colour Pattern ◽  
Gradient System ◽  
Experimental Animals ◽  
Vanessa Cardui ◽  
Adult Wing ◽  
Wing Patterns ◽  
Pattern Determination ◽  
Colour Patterns ◽  
Precis Coenia ◽  
Morphological Series

When young pupae of Vanessa cardui, V. virginiensis and Precis coenia (Lepidoptera: Nymphalidae) are exposed to severe coldshock many develop aberrant adult wing patterns. For each species, a synchronous cohort of experimental animals always develops a broad range of aberrant pattern morphologies but these can always be arranged in a single unbranched morphological series. When such phenotypic series are compared, between species and between wing surfaces within a species (each wing surface usually bears a different colour pattern), many parallel modifications and trends become evident. These parallelisms reveal certain homologies of pattern elements and suggest that a common physiology underlies the development of a considerable diversity of normal and aberrant colour patterns. The case is made that the phenotypic series produced may represent either a series of sequential stages in colour pattern determination or, a series of quantitatively different ‘interpretations’ of an established gradient system. Colour pattern morphoclines reveal which patterns are developmentally ‘adjacent’ to one another and may therefore prove useful in elucidating the evolution of patterns.

The Distribution and possible Genesis of some Organic Terrain Patterns in the Southern Mackenzie River Valley

1973 ◽  
Vol 10 (3) ◽  
pp. 432-438 ◽  
Author(s):  
C. B. Crampton
Keyword(s):  
River Valley ◽  
Morphological Series ◽  
Progressive Enlargement ◽  
Mackenzie River

Terrain types in the southern Mackenzie River valley can be arranged into morphological series which are, in part, continuous and, in part, discontinuous, so as to allow speculation on the probable evolution of organic terrain in the area from frozen to unfrozen landscapes, accompanying the long-term amelioration of the climate during postglacial times. Stipploid terrain on gentle slopes retained its lineated character during progressive thawing. Similarly, polygoid terrain on frozen flats retained its reticulate character, though progressive thawing locally was probably associated with increasingly diffuse pattern boundaries, ultimately yielding marbloid organic terrain. Some frozen terrazoid terrain of raised peat probably evolved into unfrozen polygoid peatland by a progressive enlargement of water-filled depressions.

A Graptolite Lineage from North Cardiganshire

1945 ◽  
Vol 82 (3) ◽  
pp. 97-106 ◽  
Author(s):  
John Challinor
Keyword(s):  
Evolutionary Lineage ◽  
Morphological Series

As the result of examining a considerable number of specimens belonging to the species Monograptus fimbriatus, M. raitzhainiensis, and M. triangulatus from certain strata of Llandovery age at a locality in North Cardiganshire, the writer is led to the conclusion that the forms comprised within these species constitute a continuously graded morphological series; and that the stratigraphical occurrence of these forms shows that this series is, further, an evolutionary lineage.

Aegialodon dawsoni , a new trituberculosectorial tooth from the Lower Wealden

1965 ◽  
Vol 162 (989) ◽  
pp. 535-554 ◽  
Keyword(s):  
Middle Jurassic ◽  
Upper Jurassic ◽  
Upper Triassic ◽  
Main Line ◽  
Molar Teeth ◽  
The Trinity ◽  
Morphological Expression ◽  
Morphological Series ◽  
Lower Molar

This paper describes a new mammalian tooth from the Lower Wealden bone-bed at Cliff End, near Hastings. The tooth is a lower molar. It has a trituberculate structure with a well-developed talonid. The nature of the wear on this talonid shows that a true protocone (a definite pointed cusp as against an enlarged lingual cingulum) must have been present in the upper molars. Aegialodon is the first mammal in which the existence of a definitive protocone can be inferred. A good morphological series can be traced back from Aegialodon through Peramus (Upper Jurassic), Amphitherium (Middle Jurassic) to the Upper Triassic Welsh pantotheres. This series illustrates the increasing importance of the crushing as against the shearing function of the molar teeth as their evolution progresses. The morphological expression of this development is the enlargement of the talonid and associated enlargement of the lingual cingulum of the upper molars. Finally, in the last member of the series ( Aegialodon ) the lingual cingulum becomes a true protocone. From this main line of therian evolution first the symmetrodonts and then the dryolestid pantotheres branched off by emphasizing the shearing function of the teeth and reducing their crushing function. This would have been an adaptation to an exclusively insectivorous diet. From Aegialodon can be derived the teeth of the Trinity Sands ‘ Theria ’ and Endotherium by a further increase in the size of talonid and protocone. A continuation of the same process would give rise to the teeth of marsupials and placentals.

Embryonic and Postembryonic Development in Bythotrephes cederstroemii

1992 ◽  
Vol 49 (6) ◽  
pp. 1118-1125 ◽  
Author(s):  
Peder M. Yurista
Keyword(s):  
Embryonic Development ◽  
Development Time ◽  
Lake Michigan ◽  
Field Work ◽  
Postembryonic Development ◽  
Complete Life Cycle ◽  
Development Data ◽  
Series Development ◽  
Data Log ◽  
Morphological Series

Laboratory observations were made of embryonic development time for parthenogenic Bythotrephes cederstroemii under differing temperatures spanning the range when Bythotrephes may be present in the plankton of Lake Michigan. Postembryonic development was documented for parthenogenically produced and sexually produced offspring. The complete life cycle of Bythotrephes was observed to have two distinct morphological series. Development time from birth to primaparity, consisting of three instars, was 14.0 ± 1.63 d at 12.7 °C for pathenogenically produced offspring. Development time at 12.7 °C for gametogenically produced offspring was 13.7 ± 1.57 d with four instars. Because parthenogenic eggs released into the brood sac of Bythotrephes do not become obvious until the embryo development is well advanced, a useful model for birth rate calculations in field work was developed based on observable morphological traits of the embryos within the brood sac. A curvilinear logarithmic model of development time (D, hours) as a function of temperature (T degrees Celsius) was fit to the embryonic development data: log (D) = 6.840–7.305log(T) + 2.490log(T)2.

scholarly journals RGB Inter-Channel Measures for Morphological Color Texture Characterization

Symmetry ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1190
Author(s):  
Nelson Luis Durañona Durañona Sosa ◽  
José Luis Vázquez Vázquez Noguera ◽  
Juan José Cáceres Cáceres Silva ◽  
Miguel García García Torres ◽  
and Horacio Legal-Ayala
Keyword(s):  
Image Processing ◽  
State Of The Art ◽  
Texture Classification ◽  
Texture Descriptor ◽  
Classification Techniques ◽  
Rgb Images ◽  
Different Color ◽  
High Level ◽  
Texture Characterization ◽  
Morphological Series

The perception of textures is based on high-level features such as symmetry, brightness, color or direction. Texture characterization is a widely studied topic in the image processing community. The normalized volume of morphological series is used as a texture descriptor in RGB images. However, the correlation between different color channels is not exploited with this descriptor. We propose the usage of inter-channel measures in addition to the volume, to enhance the descriptors potential to discriminate textures. The experiments show that standard texture classification techniques increase between 3%–10% in performance when using our descriptor instead of other state of the art descriptors that do not use inter-channel measures.

Some relations between common acid–basic associations

1971 ◽  
Vol 108 (6) ◽  
pp. 525-531 ◽  
Author(s):  
M. J. Roobol
Keyword(s):  
Basic Magma ◽  
Degree Of Consolidation ◽  
Morphological Series

SummaryNet veined complexes and basic dykes with lobate or planar margins are commonly contained in granophyre and felsite. A study of three Tertiary centres reveals that the associations do not occur as distinct types but show gradational relations. Examples are used to illustrate a gradational morphological series. The interpretation of this series is best accounted for in terms of a basic magma invading an acid host. The factors considered capable of producing the described variations are (a) the volume of basic magma (and therefore amount of heat introduced), and (b) the degree of consolidation (ratio of crystals to melt) of the acid host.

Hantkenina alabamensis Cushman and Some Related Forms

1954 ◽  
Vol 91 (5) ◽  
pp. 384-390 ◽  
Author(s):  
Tom Barnard
Keyword(s):  
The Status ◽  
Morphological Series

AbstractSome variations in the apertures of Cribrohantkenina are arranged in morphological series. The development of the “cribrate” aperture and its relation to other biocharacters, such as the shape of the chambers, development of spines, and globosity of the chambers, is discussed, as also the status of the subgenera of the genus Hantkenina.

Sign in / Sign up

Export Citation Format

Share Document