CHROMOSOME NUMBER POLYMORPHISM IN AN AUSTRALIAN PONERINE ANT

1969 ◽  
Vol 11 (2) ◽  
pp. 333-339 ◽  
Author(s):  
R. H. Crozier
Keyword(s):  
Chromosome Number ◽  
Sibling Species ◽  
Related Species ◽  
Ponerine Ant ◽  
Robertsonian System

Southern Victorian populations of Rhytidoponera metallica have n = 22 to 17, with progressive replacement of two acrocentrics at a time by a metacentric to yield numbers lower than 22 (nombre fondamentale = 23). A further collection with n = 12 represents either a further reduction in this Robertsonian system or a sibling species. Related species have n = 21 (victoriae) and 23 (tasmaniensis).

A new species of Gomesa (Oncidiinae, Orchidaceae) from inselbergs in Brazilian caatinga: morphological and karyological evidence

Phytotaxa ◽  
2018 ◽  
Vol 374 (2) ◽  
pp. 147 ◽  
Author(s):  
JOEL M. P. CORDEIRO ◽  
FELIPE NOLLET ◽  
MARIA TERESA BURIL ◽  
MARK W. CHASE ◽  
LEONARDO P. FELIX
Keyword(s):  
New Species ◽  
Chromosome Number ◽  
Geographical Distribution ◽  
Related Species ◽  
Species Differences ◽  
Flower Morphology ◽  
Closely Related Species ◽  
Restricted Distribution ◽  
A New Species

We describe a new species of Gomesa (Oncidiinae, Orchidaceae), Gomesa caatingana, with restricted distribution on caatinga inselbergs in Paraíba and Pernambuco States, Brazil. Morphological and karyological characters of the new species were compared with those of Gomesa flexuosa, which is morphologically the most closely related species. Differences in geographical distribution, habit, flower morphology and chromosome number support description of this new species.

scholarly journals Contact-Chemosensory Evolution Underlying Reproductive Isolation in Drosophila Species

2020 ◽  
Vol 14 ◽  
Author(s):  
Kosei Sato ◽  
Daisuke Yamamoto
Keyword(s):  
Decision Making ◽  
Mate Choice ◽  
Reproductive Isolation ◽  
Sibling Species ◽  
Related Species ◽  
Main Theme ◽  
Biological Factors ◽  
Premating Isolation ◽  
Closely Related Species ◽  
Neural Activities

The main theme of the review is how changes in pheromone biochemistry and the sensory circuits underlying pheromone detection contribute to mate choice and reproductive isolation. The review focuses primarily on gustatory and non-volatile signals in Drosophila. Premating isolation is prevalent among closely related species. In Drosophila, preference for conspecifics against other species in mate choice underlies premating isolation, and such preference relies on contact chemosensory communications between a female and male along with other biological factors. For example, although D. simulans and D. melanogaster are sibling species that yield hybrids, their premating isolation is maintained primarily by the contrasting effects of 7,11-heptacosadiene (7,11-HD), a predominant female pheromone in D. melanogaster, on males of the two species: it attracts D. melanogaster males and repels D. simulans males. The contrasting preference for 7,11-HD in males of these two species is mainly ascribed to opposite effects of 7,11-HD on neural activities in the courtship decision-making neurons in the male brain: 7,11-HD provokes both excitatory and inhibitory inputs in these neurons and differences in the balance between the two counteracting inputs result in the contrasting preference for 7,11-HD, i.e., attraction in D. melanogaster and repulsion in D. simulans. Introduction of two double bonds is a key step in 7,11-HD biosynthesis and is mediated by the desaturase desatF, which is active in D. melanogaster females but transcriptionally inactivated in D. simulans females. Thus, 7,11-HD biosynthesis diversified in females and 7,11-HD perception diversified in males, yet it remains elusive how concordance of the changes in the two sexes was attained in evolution.

Étude caryologique de trois espèces d’Hypochoeris originaires d'Argentine : H. chillensis, H. microcephala var. albiflora et H. megapotamica

1994 ◽  
Vol 72 (10) ◽  
pp. 1496-1502 ◽  
Author(s):  
S. Siljak-Yakovlev ◽  
A. Bartoli ◽  
G. Roitman ◽  
N. Barghi ◽  
C. Mugnier
Keyword(s):  
Chromosome Number ◽  
Related Species ◽  
Secondary Constriction ◽  
Nucleolar Organizer ◽  
Asymmetry Index ◽  
Evolutionary Trend ◽  
Closely Related Species ◽  
Nucleolar Organizers ◽  
Morphological Differences ◽  
Secondary Constrictions

Three Hypochoeris species from Argentina with the same chromosome number (x = 4) and similar karyotypes (typically bimodal) show significant ecological and morphological differences. Comparative cytogenetic analysis was done for these taxa, producing karyotypes with correlated idiograms. The number of secondary constrictions and nucleolar organizers varied. The results from this study are discussed in terms of the mechanisms of microevolution within this group of closely related species, and in terms of the evolutionary trend in the genus and in the tribe Cichorieae. Key words: Hypochoeris, Cichorieae, bimodal karyotype, secondary constriction, nucleolar organizer, asymmetry index.

A new species of Trigonella sect. Ellipticae (Leguminosae-Papilionoideae) from Iran, including cytogenetic and anatomical notes

Phytotaxa ◽  
2015 ◽  
Vol 202 (1) ◽  
pp. 26 ◽  
Author(s):  
Massoud Ranjbar ◽  
ZAHRA HAJMORADI
Keyword(s):  
New Species ◽  
Chromosome Number ◽  
Related Species ◽  
Somatic Chromosome ◽  
Base Number ◽  
Somatic Chromosome Number ◽  
Chromosome Counts ◽  
Closely Related Species ◽  
A New Species

A new species, Trigonella bakhtiarica, from the Iranian province Chahar Mahal Va Bakhtiari is described, illustrated and compared to its most closely related species, T. aphanoneura. Trigonella bakhtiarica has a longer corolla and differs in the shape, surface and size of its pods, which are taxonomically informative characters in Trigonella sect. Ellipticae. Chromosome counts and meiosis assays show that both species are diploid, and that their euploid plants possess a somatic chromosome number of 2n = 2x = 16, which is consistent with the predicted base number of x = 8.

A clarification of Medicago sinskiae

1991 ◽  
Vol 69 (1) ◽  
pp. 100-106 ◽  
Author(s):  
Ernest Small ◽  
Brenda Brookes
Keyword(s):  
Chromosome Number ◽  
Key Words ◽  
Related Species ◽  
The Other ◽  
Species Status ◽  
Closely Related Species

Little information has been available to justify the species status of the rare Turkmenian Medicago sinskiae Uljan. recognized by Uljanova in 1964. The holotype and plants raised from its seeds were examined, the chromosome number was determined, and a numerical taxonomic comparison was made of M. sinskiae and the other 12 species of Medicago section Spirocarpos subsection Pachyspirae. It was found that M. sinskiae is well separated from the most closely related species of Medicago and deserves recognition at the rank of species. Key words: Medicago sinskiae, Leguminoseae, alfalfa, taxonomy.

Centaurea stuessyi (Compositae: Cardueae), a new species from the eastern Iberian Peninsula

Phytotaxa ◽  
2013 ◽  
Vol 115 (2) ◽  
pp. 42 ◽  
Author(s):  
ITZIAR ARNELAS ◽  
JUAN ANTONIO DEVESA ◽  
EUSEBIO LÓPEZ
Keyword(s):  
New Species ◽  
Chromosome Number ◽  
Iberian Peninsula ◽  
Related Species ◽  
Ecological Preferences ◽  
A New Species

Centaurea stuessyi is described as new to science from the eastern Iberian Peninsula, Spain. The range of this new species coincides with the zone of overlap of the ranges of two related species, C. antennata (subsp. antennata) and C. linifolia. The chromosome number found in the new species (2n = 44) reinforces its differences from C. linifolia (2n = 22) and C. antennata (2n = 22). The new species is compared with related species, and a description is given of its ecological preferences.

scholarly journals Contribution to the Knowledge of the GenusLindaThomson, 1864 (Part I), with the Description ofLinda(Linda)subatricornisn. sp. from China (Coleoptera, Cerambycidae, Lamiinae)

2012 ◽  
Vol 2012 ◽  
pp. 1-8
Author(s):  
Mei-Ying Lin ◽  
Xing-Ke Yang
Keyword(s):  
Sibling Species ◽  
Related Species ◽  
Similar Species ◽  
Short Discussion

Linda (Linda) subatricornisn. sp is described from Sichuan (holotype locality), Fujian, Shaanxi, Hebei, Ningxia of China. It is separated from the most similar speciesL. atricornisPic by differences in genitalia and antennal insertions. Detailed descriptions, photographs of habitus and genitalia, distribution of the two sibling species and short discussion on the related species are presented.

Cytotaxonomic studies of Draba species of Canada and Alaska: D. ventosa, D. ruaxes, and D. paysonii

1971 ◽  
Vol 49 (8) ◽  
pp. 1455-1460 ◽  
Author(s):  
Gerald A. Mulligan
Keyword(s):  
North America ◽  
Chromosome Number ◽  
Related Species ◽  
Basic Chromosome Number ◽  
Base Number ◽  
Western North America ◽  
Closely Related Species ◽  
Basic Chromosome ◽  
Hexaploid Species

The cytotaxonomy of three closely related species of Draba, of the mountains of western North America, is discussed and a key is given: D. ventosa A. Gray (2n = 36), D. ruaxes Payson & St. John (2n = ca. 72), and D. paysonii Macbride (2n = 42). Evidence is presented demonstrating that D. ventosa and D. paysonii are triploids reproducing by agamospermy whereas the hexaploid species D. ruaxes is a sexual outcrosser. The former two species produce seed apomictically without any pollen stimulation. Draba ventosa and D. ruaxes have the basic chromosome number x = 12 and D. paysonii has the base number x = 14.

Chromosomal similarities and differences among three sibling species of the Acalles echinatus group (Coleoptera, Curculionidae, Cryptorhynchinae)

Zootaxa ◽  
2009 ◽  
Vol 1985 (1) ◽  
pp. 63-68 ◽  
Author(s):  
DOROTA LACHOWSKA ◽  
MARIA ROŻEK ◽  
MILADA HOLECOVÀ
Keyword(s):  
Chromosome Number ◽  
Sibling Species ◽  
Karyotype Evolution ◽  
Relative Length ◽  
Silver Impregnation ◽  
Modal Formula ◽  
Meiotic Chromosomes ◽  
Group A ◽  
Determination System ◽  
Sex Determination System

In order to clarify the taxonomic position of three sibling species of weevils from the Acalles echinatus group, A. echinatus, A. fallax and A. petryszaki, cytogenetic relationships are investigated by studying the mitotic and meiotic chromosomes, including the localisation of heterochromatin by C-banding, as well as the localisation of NORs by silver impregnation. These sources of data are congruent and strongly support that the examined species are closely related. All examined species are characterised by a karyotype of the same chromosome number and sex determination system but with different morphology of chromosomes. All the analysed features, such as the centromeric index, relative length, Cbands and NORs, show that the structure of the karyotype of A. echinatus is more similar to that of A. petryszaki, whereas the karyotype of A. fallax is divergent. The higher chromosome number (2n = 30) in relation to the modal formula in Curculionidae (2n = 22) suggests that karyotype evolution in these species could have occurred by centric fissions of metacentric elements leading to acrocentry.

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