CYTOTAXONOMY OF BOMBYLIIDAE (DIPTERA)

1973 ◽  
Vol 15 (1) ◽  
pp. 21-37 ◽  
Author(s):  
J. W. Boyes ◽  
G. E. Shewell

The karyotypes of 34 species of Bombyliidae are described, some in greater detail than others. It is suggested that two subfamilies, the Bombyliinae (for Homoeophthalmae) and Anthracinae (for Tomophthalmae) be recognized. In the Bombyliinae, one species has 2n = 8, one 2n = 10, three 2n = 12 and one 2n = 14. In the Anthracinae, two species have 2n = 10, four 2n = 12, six 2n = 14, three 2n = 16 and thirteen 2n = 18. Seventeen complements of Bombyliinae averaged 41.4 μ in total complement length (TCL) and thirtyeight of Anthracinae averaged 46.6 μ; so the 55 complements of the Bombyliidae averaged 44.9 μ in TCL, the complements with lower chromosome numbers averaging less than those with higher numbers. Thus Bombyliinae species have lower chromosome numbers and shorter complements than Anthracinae species which tend to have longer metacentric sex chromosomes. Thus both morphologically and karyotypically the Bombyliinae appear to be more advanced whereas the Anthracinae are a more primitive but highly variable group of species.

Genetika ◽  
2017 ◽  
Vol 49 (1) ◽  
pp. 285-295 ◽  
Author(s):  
A.H. Abu-Almaaty

Study of karyotypes has been revealing important information on the taxonomic relationships and evolutionary patterns in various groups of birds. Karyotypes analysis and morphometric measurement of the chromosomes of three birds species of Geopelia cuneata (Columbiformes), Oriolus oriolus and Corvus ruficollis (Passeriformes) and their karyological have been studied. The diploid chromosome numbers of three species were, 2n=72, 2n=80 and 2n =80 respectively. The karyotypes of three species were different. The somatic and sex chromosomes and karyotypes of three species discussed and compared with other related species in the present study.


Zootaxa ◽  
2011 ◽  
Vol 2872 (1) ◽  
pp. 49
Author(s):  
WILLIE HENRY ◽  
SACHIN THAPA ◽  
PETER H. ADLER ◽  
SUBRATA KUMAR DEY ◽  
RAKESH VARMA

The polytene chromosomes are mapped for a scarce Himalayan simuliid, Simulium (Montisimulium) ghoomense Datta, from the Darjeeling area of India. This species has three tightly paired polytene chromosomes with a haploid number of 3. Chromosomes I, II, and III account for 39.6%, 30.3%, and 30.1% of the total complement length, respectively. The centromeres of chromosomes II and III consistently form a putative partial chromocenter. Sex chromosomes are undifferentiated and polymorphisms and sibling species are lacking in a sample of 35 larvae. This is the first chromosomal map for a species in the subgenus Montisimulium in India.


1957 ◽  
Vol 35 (3) ◽  
pp. 453-458 ◽  
Author(s):  
J. G. Robertson

A comparative study of somatic metaphase complements of the carrot rust fly, Chamaepsila rosae (F.), from England, Prince Edward Island, Ontario, and British Columbia showed that the chromosome number is eight and that all chromosomes are metacentric. The means of the total complement length ranged from 50.8 to 53.5 and the lengths for chromosomal pairs I–IV averaged 36.5, 24.8, 22.3, and 16.5% of the total length respectively for the four regions. The sex chromosomes are the largest elements in the complement, the X chromosome being 36.5% of the total length and the Y 28.8%. The arm ratios for members X, Y, II, III, and IV are 1.34, 1.13, 1.57, 1.21, and 1.34 respectively. Secondary constrictions were both infrequent and irregular in location. The work emphasizes that much caution is necessary in analyzing metaphase chromosomes for taxonomic purposes.


2020 ◽  
Vol 69 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Shubhi Rastogi ◽  
Deepak Ohri

AbstractThe present report is based on a cytological data base on 614 (56.0 %) of the total 1104 recognized species and 82 (90.0 %) of the 88 recognized genera of gymnosperms. Family Cycadaceae and many genera of Zamiaceae show intrageneric uniformity of somatic numbers, the genus Zamia is represented by a range of number from 2n=16-28. Ginkgo, Welwitschia and Gentum show 2n=24, 2n=42, and 2n=44 respectively. Ephedra shows a range of polyploidy from 2x-8x based on n=7. The family Pinaceae as a whole shows 2n=24except for Pseudolarix and Pseudotsuga with 2n=44 and 2n=26 respectively. Araucariaceae constantly shows 2n=26 while Podocarpaceae has a range of 2n=18-38. Sciadopityaceae and Cupressaceae are represented by 2n=20 and 2n=22 respectively. Taxaceae shows variable numbers of 2n=24, 36 and 22. Polyploidy is exceptional being represented by 8.0 % of the taxa studied. B-chromosomes have been studied in 31 taxa while heteromorphic sex chromosomes have been reported in some dioecious taxa.


1973 ◽  
Vol 21 (1) ◽  
pp. 21 ◽  
Author(s):  
M King

The mitotic chromosomes of nine species from five genera of the saurian family Scincidae are presented. Chromosome numbers and karyotypic morphology support the taxonomic subdivision of these lizards into the subfamilies Lygosominae (2n=30) and Scincinae (2n=32). A model for the chromosomal evolution of these species is postulated. Variability in chromosomal morphology is minimal though certain intergeneric and species differences were detected. Heteromorphic sex chromosomes were not observed.


1968 ◽  
Vol 10 (2) ◽  
pp. 390-394 ◽  
Author(s):  
Parvathi K. Basrur

The somatic chromosomes of the long tailed weasel, Mustela frenata from Southern Ontario were studied using tissue culture methods. The autosomes include 11 pairs of biarmed elements ranging from 2.0 to 8.15 in per cent total complement length and 9 pairs of single armed elements ranging from 3.2 to 5.00. Five of the biarmed chromosomes are metacentrics (M) ranging in arm ratio from 1.2 to 1.35 and the remaining six are submetacentrics (S) varying in arm ratio from 1.7 to 3.5. The sex chromosomes are biarmed, the X being the second smallest of the S series, whereas the Y is the smallest.


Genome ◽  
1989 ◽  
Vol 32 (6) ◽  
pp. 1119-1123
Author(s):  
J. D. Murray ◽  
G. M. McKay ◽  
J. W. Winter ◽  
S. Ingleby

The two Herbert River ringtail possum subspecies, Pseudocheirus herbertensis ssp. herbertensis and P. h. ssp. cinereus, have diploid chromosome numbers of 12 and 16, respectively. The sex chromosomes of both subspecies are exceptionally large, with the X and Y chromosomes being approximately 16 and 12% of the haploid autosomal complement, respectively. A sex chromosome bivalent cannot be identified during male meiosis and a sex vesicle is not present during pachytene. The two karyotypes are most likely related by two centric fusion events affecting the autosomal complement. We conclude that the X and Y chromosomes have been translocated onto homologous autosomes to give t(XA) t(YA) ♀ t(XA) t(XA) ♂. Our data also strongly support the separation of P. h. cinereus as a distinct species.Key words: karyotypes, sex chromosomes, speciation.


1953 ◽  
Vol 31 (2) ◽  
pp. 125-165 ◽  
Author(s):  
J. W. Boyes ◽  
A. Wilkes

A method of analysis of somatic chromosome complements in cells of the brains of larvae and pupae is presented. Tachinid species have regularly 12 chromosomes in their somatic complements. These consist of five metacentric pairs and a pair of sex chromosomes which are acrocentric in most species. Careful measurement, on drawings, of each arm of each chromosome provides a basis for calculating the percentage that each pair constitutes of the total complement length and for determining the ratio of the long to the short arm for each pair. Results of analysis and other distinguishing features of the chromosome complements are presented for Aplomya caesar, A. mitis, Ceracia dentata, Ceromasia auricaudata, Drino bohemica, Eumea westermanni, Lydella grisescens, Madremyia saundersii, Mericia ampelus, Nemorilla pyste, Neophorocera hamata, Omotoma fumiferanae, Phryxe pecosensis, Spathimeigenia sp., Winthemia datanae, and W. occidentis. Most of these species can be distinguished by differences in the morphology of their chromosomes.


1970 ◽  
Vol 12 (2) ◽  
pp. 273-277 ◽  
Author(s):  
Yasushi Takenouchi

The chromosomes of three Japanese weevil species, two parthenogenetic and one bisexual, are described for the-first time. Males of the alate Cyrtepistomus castaneus are unknown. Oogonial metaphases had standard, 3x = 30, and substandard, 3x = 31, chromosome numbers (range ca. 28 — ca. 33). No reduction occurs at meiosis (ca. 30 univalents at MI). This species is therefore considered to be a triploid parthenote. Eight oocyte metaphases of Blosyrus japonicus, which also appears to lack males, showed between 66 and 61 (or 60) univalent chromosomes (two had 66, three had 65). These counts categorize the mothers as thelytokous hexaploids, a degree of polyploidy not previously found in the Curculionidae. The male of the bisexual Ceuthorrhynchus lewisi (2n = 28) possesses an unusually large pair of sex chromosomes. The metacentric X and telocentric Y form an achiasmate, umbrella-like bivalent that is unique among known Coleoptera.


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