Variability of Relative Body Chamber Length in Jurassic Ammonites of the Family Cardioceratidae Siemiradzki, 1891, and Its Taxonomic Significance

2018 ◽  
Vol 52 (13) ◽  
pp. 1517-1544
Author(s):  
D. N. Kiselev
Keyword(s):  
Taxonomic Significance ◽  
Chamber Length ◽  
Body Chamber ◽  
The Family

Cassiavellia galtarae, new species, new genus: a new Permian bivalve and its significance for pterioidean systematics

2010 ◽  
Vol 84 (6) ◽  
pp. 1152-1176 ◽  
Author(s):  
Ilya Tëmkin ◽  
John Pojeta
Keyword(s):  
New Species ◽  
New Genus ◽  
Larval Shell ◽  
Upper Permian ◽  
Taxonomic Significance ◽  
New Genus And Species ◽  
The Family ◽  
Dental Ontogeny

An exceptionally well-preserved silicified bivalve from the Upper Permian of Texas is described and assigned to a new genus and species,Cassiavellia galtarae, placed in the family Bakevelliidae. The species represents one of the earliest and best characterized unequivocal occurrences of the multivincular ligament in the superfamily Pterioidea. The silicified material provides a wealth of information on the morphology of inadequately known Paleozoic pterioideans, including hitherto undescribed aspects of the larval shell, auricular sulcus, muscle scars, and dental ontogeny. The discovery of the condyle-fossa complex on the anteroventral shell margin, a feature previously undescibed in Bivalvia, raises the question of the homology and taxonomic significance of the problematic subumbonal ridge-like structures in Pterioidea. In life,C. galtaraewas probably an epifaunal right-pleurothetic bivalve, byssally attached to hard or raised flexible substrata. In addition toC. galtarae, another new species,C. nadkevnae, is placed inCassiavellia.

Fruit developmental biology and endosperm rumination in Elaeocarpus ruminatus (Elaeocarpaceae), and its taxonomic significance

2018 ◽  
Author(s):  
Janet N. Gagul ◽  
David Y. P. Tng ◽  
Darren M. Crayn
Keyword(s):  
Developmental Biology ◽  
Adaptive Significance ◽  
Evolutionary Significance ◽  
Phylogenetic Distribution ◽  
Taxonomic Significance ◽  
The Family ◽  
Developmental Phases ◽  
Trees And Shrubs ◽  
Insight Into ◽  
Gaining Insight

The genus Elaeocarpus is the largest genus in the family Elaeocarpaceae, comprising more than 350 species of trees and shrubs with a mainly Indo-Pacific distribution. Approximately 28 species in the genus, including nine species from Australia, are known to possess ruminate endosperm. To provide a basis for understanding fruit development and endosperm rumination in the genus and, therefore, its taxonomic and evolutionary significance, we studied the fruit anatomy of Elaeocarpus ruminatus F.Muell. at different developmental phases (petal-fall to maturity). We found lignin in pericarp and ovary wall tissues in the earliest stages of development. In contrast, endosperm rumination occurs only after fruits have fully expanded, and becomes more pronounced as fruits ripen. Its phylogenetic distribution suggests that ruminate endosperm is a derived, albeit homoplasious character in Elaeocarpus. Comparative studies on related species will be instructive in determining the utility of ruminate endosperm for informing infra-generic taxonomy of the genus, and gaining insight into its adaptive significance.

Extrafloral nectaries in Combretaceae: morphology, anatomy and taxonomic significance

Bothalia ◽  
2004 ◽  
Vol 34 (2) ◽  
pp. 115-126 ◽  
Author(s):  
P. M. Tilney ◽  
A. E. Van Wyk
Keyword(s):  
Species Level ◽  
Extrafloral Nectaries ◽  
Small Cells ◽  
Extrafloral Nectar ◽  
Taxonomic Significance ◽  
Sugar Composition ◽  
Separate Species ◽  
The Family

Extrafloral nectaries (EFNs) in members of the Combretaceae are nectaries not involved with pollination and occurring on vegetative structures; they are believed to attract ants to protect plants against herbivorv by other insects. In the Combretaceae EFNs are reported in species of Terminalia L. and Pteleopsis Engl., putative EFNs in Meiostemon Exell Stace and Quisqualis L., and an absence of EFNs in Combretum Loefl. and Lumnitzera Willd. EFNs in the family are generally spherical in shape and may be raised, level with the surface or somewhat concave. They are similar in the Terminalia and  Pteleopsis species where they display varying degrees of internal zonation and are composed of small cells; those species observed in the field were all found to have functional EFNs. In Meiostemon tetrandrum (Exell) Exell Stace, Quisqualis indica L.. Q. littorea (Engl.) Exell and Q. paviflora Gerrard ex Sond.. apparent EFNs lack internal zonation and are composed of enlarged cells; confirmation is required as to whether these are functional . The formation of EFNs appears to be highly flexible. They are usually essentially associated with new growth but their occurrence is sporadic and they do not appear on every leaf or every' branch of a plant. The distribution of EFNs on leaves, when present, is of taxonomic significance to separate species of Pteleopsis and Terminalia: otherwise the presence or absence and distribution of EFNs are too variable and sporadic in occurrence to be of taxonomic significance at the species level. Indiscriminate use of the terms gland and domatium instead of EFN. and possible confusion with damage caused by other organisms, has probably con­tributed to many of these structures not previously being recorded as EFNs. Floral and extrafloral nectar samples of T. phanerophlebia Engl. Diels differed in sugar composition.

scholarly journals Taxonomic significance of spermoderm pattern in Cucurbitaceae

2013 ◽  
Vol 20 (1) ◽  
pp. 61-65
Author(s):  
M. Ajmal Ali ◽  
Fahad M.A. Al-Hemaid ◽  
Arun K. Pandey ◽  
Joongku Lee
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Cucumis Melo ◽  
Taxonomic Significance ◽  
Citrullus Colocynthis ◽  
Benincasa Hispida ◽  
The Family ◽  
Plant Taxon ◽  
Relationship Of ◽  
Scanning Electron

Studies on spermoderm using scanning electron microscope (SEM) were undertaken in 12 taxa under 11 genera of the family Cucurbitaceae sampled from India, China and Korea. The spermoderm pattern in the studied taxa varies from rugulate, reticulate to colliculate type. The spermoderm shows rugulate type in Benincasa hispida and Sicyos angulatus; reticulate type in Citrullus colocynthis, Cucumis melo var. agrestis, Diplocyclos palmatus, Hemsleya longivillosa, Luffa echinata, Momordica charantia, M. cymbalaria, Schizopepon bryoniifolius, and Trichosanthes cucumerina; and colliculate type  in Gynostemma laxiflorum. The present study clearly reveals that the testa features greatly varies across the genera which can be used as micromorphological markers for identification as well as character states for deducing relationship of the taxa within the family.DOI: http://dx.doi.org/10.3329/bjpt.v20i1.15465Bangladesh J. Plant Taxon. 20(1): 61-65, 2013 (June)

Sagenidiopsis, A New Genus Of Byssoid Lichenized Fungi

1987 ◽  
Vol 19 (4) ◽  
pp. 401-408 ◽  
Author(s):  
R. W. Rogers ◽  
J. Hafellner
Keyword(s):  
New Genus ◽  
Lichenized Fungi ◽  
Taxonomic Significance ◽  
Eastern Australia ◽  
The Family ◽  
Cool Temperate ◽  
Family Level ◽  
Temperate Rainforests ◽  
Amyloid Structures

AbstractThe genus Sagenidiopsis gen. nov. of uncertain family in the order Opegraphales is erected for a byssoid lichen which occurs in the cool temperate rainforests of the Macpherson Range of eastern Australia, S. merrotsii sp. nov. The genus is characterized by its byssoid thallus and bitunicate asci which have no amyloid structures apparent in the tholus. A byssoid thallus is without taxonomic significance at the family level, but is an ecological key character.

Sublethal injury and shell repair in Upper Mississippian ammonoids

Paleobiology ◽  
1989 ◽  
Vol 15 (4) ◽  
pp. 414-428 ◽  
Author(s):  
Paul N. Bond ◽  
W. Bruce Saunders
Keyword(s):  
Shell Thickness ◽  
Physical Parameters ◽  
Selective Predation ◽  
Chamber Length ◽  
Body Chamber ◽  
Interspecific Differences ◽  
Sublethal Injury ◽  
Shell Damage ◽  
Shell Repair ◽  
Northwest Arkansas

Sublethal injuries recorded in the shells of five Upper Mississippian ammonoid species from the Imo Formation of northwest Arkansas are manifested as repaired shell breaks, which can be categorized as minor, moderate, massive, deep-acute, or as perforations. Overall, 15% of the ammonoids exhibit some form of repaired break. The injuries are distributed as follows: Anthracoceras discus 9%; Fayettevillea bransoni 13%; Fayettevillea friscoense 21%; Rhadinites miseri 24%; Richardsonites mapesi 38%. These figures are substantially lower than in living Nautilus, in which more than one-half of adult specimens exhibit repaired shell breaks. The different frequencies of injuries may reflect species-selective predation, differential abilities to sustain and to repair shell damage, or they may be due to interspecific differences in physical parameters such as shell thickness and body chamber length. The most likely possible perpetrators of the injuries include sharks, other fishes, and cephalopods.

Stratigraphic and taxonomic significance of Tusoteuthis longa Logan (Coleoidea, Teuthida) from the Pembina Member, Pierre Shale (Campanian), of Manitoba

1987 ◽  
Vol 61 (4) ◽  
pp. 727-737 ◽  
Author(s):  
Elizabeth L. Nicholls ◽  
Henry Isaak
Keyword(s):  
Upper Cretaceous ◽  
Taxonomic Significance ◽  
Niobrara Formation ◽  
Pierre Shale ◽  
The Family

The fossilized gladii of six squid from the Pembina Member of the Pierre Shale (Upper Cretaceous, Campanian) of southern Manitoba are referred to Tusoteuthis longa Logan, 1898, a species previously reported only from the Niobrara Formation of Kansas. The characters used to identify the genus are reviewed and it is referred to the family Kelaenidae. Documentation of these specimens extends the range of both the genus and the family to the Campanian of Canada.

The significance of the tail projections in female entomopathogenic nematodes within the family Steinernematidae

2015 ◽  
Vol 90 (2) ◽  
pp. 249-251 ◽  
Author(s):  
Z. Mráček ◽  
V. Půža ◽  
J. Nermut'
Keyword(s):  
Entomopathogenic Nematodes ◽  
First Generation ◽  
Entomopathogenic Nematode ◽  
Species Level ◽  
Taxonomic Significance ◽  
Female Tail ◽  
The Family ◽  
Taxonomic Studies ◽  
A New Species ◽  
Scanning Electron

AbstractSeveral taxonomic studies of the entomopathogenic nematode family Steinernematidae have reported on the minute tail projections on the tail tips of females of the first generation; however, the occurrence and morphology of these traits in other steinernematid species and their taxonomic significance are still unclear. In the present study, the tail projections in females of seven steinernematid species belonging to four phylogenetic clades were examined. The projections are present in all of the tested species and their number and shape is consistent within species but significantly differs among species. It thus seems that these structures may have taxonomic significance at the species level. Based on these results, we suggest that every description of a new species in the family Steinernematidae should contain a precise morphology of the female tail, focused on these projections, using both light and scanning electron microscopy.

Morphology and taxonomic significance of the leaf epicuticular waxes in the Epacridaceae

1994 ◽  
Vol 7 (2) ◽  
pp. 125 ◽  
Author(s):  
CM Weiller ◽  
RK Crowden ◽  
JM Powell
Keyword(s):  
Epicuticular Waxes ◽  
Taxonomic Significance ◽  
Leaf Lamina ◽  
Evolutionary Pathway ◽  
Generic Delimitation ◽  
The Family

The leaf epicuticular waxes of all genera within the Epacridaceae have been studied. Amorphous wax and three structured wax types, namely plate, ribbon and tube wax are described and their occurrence within genera surveyed. The distribution and development of waxes on the leaf lamina surfaces and on petioles is outlined and the consistency of wax-types within species examined. Additional features such as the presence of papillae and trichomes, the distribution of stomata, and the distribution and prominence of cuticular outgrowths have been observed, extending earlier studies of these features. Amorphous wax and plate wax are widespread within the family, while tube wax is found only in two genera (Dracophyllum and Richea) and ribbon wax is restricted to genera within the tribe Styphelieae. An evolutionary pathway from ancestral amorphous wax to plate wax, with later independent development of tube wax and ribbon wax is suggested. The taxonomic value of the wax data is discussed in relation to current generic delimitation and supra-generic classification and to recently proposed changes.

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