Contributions to the cytology of Indian scorpions

Abstract

C o n t r i b u t i o n s to the C y t o l o g y of I n d i a n S c o r p i o n sThe . This is due to hypocoiling of the chromosomes. While t h e possibility of colchicine inducing constrictions u n r e l a t e d to kinetochore exists, the revealing of unseen constrictions is of interest. The c h r o m o s o m e b e h a v i o u r in Bulhus tamulus of S o u t h I n d i a is unique because, in the testicular cells of t h e s a m e individual, the following t h r e e t y p e s of orientat i o n a t m e t a p h a s e I and a n a p h a s e I are e n c o u n t e r e d : (1) t h e axes of c h r o m o s o m e s are at r i g h t angles to t h e equatorial plate, suggesting m o n o c e n t r y ( Figure d) ; (2) the axes of c h r o m o s o m e s are parallel to t h e e q u a t o r i a l axis, suggesting diffused or holokinetic n a t u r e ( Figure h); a n d (3) t h e crescentic a p p e a r a n c e of chromosomes, suggesting b i c e n t r y (Figure i). The crescentic n a t u r e of c h r o m o s o m e s of B. tamulus of Mysore S t a t e are a m e n a b l e for interpret a t i o n as inonocentric, bicentric, a n d hotokinetic. This o b s e r v a t i o n w a r r a n t s a r e a s s e s s m e n t of our opinion n o t only of kinetochore b u t also the axis relationships as criteria for designation of c h r o m o s o m e types. This is especially so in the light of t h e o b s e r v a t i o n s of RHOADES and VELKOMERSON 16 on p l a n t chromosomes, in w h i c h t h e y h a v e s h o w n 'neocentric' a c t i v i t y of n o n -c e n t r o m e r i e regions of the c h r o m o s o m e . F u r t h e r , c h r o m o s o m e s of B. tamulus d e s i g n a t e d as m o n o c e n t r i c c a n n o t be reconciled w i t h t h e fact t h a t t h e r e is a higher degree of v a r i a b i l i t y i n t e r p r e t a b l e only b y breakage and r e t e n t i o n of chromos o m e bits in t h e k a r y o t y p e . This o b s e r v a t i o n can be explained only on the basis of t h e holokinetic n a t u r e of t h e c h r o m o s o m e s . Zusammen[assung.Die C h r o m o s o m e n z a h l von Heterometrus scaber ist 96. Wird Palamnaeus swammerdami m i t Colchicin (0,2%) b e h a n d e l t , so ziehen sich die Chromos o m e n in der Pr~imetaphase I z u s a m m e n . Buthus lamulus (aus Mysore) zeigt w e i t g e h e n d variable C h r o m o s o m e n z a h l (20 28). Die L a g e der C h r o m o s o m e n in der M e t a p h a s e I und A n a p h a s e i weist auf Monozentrie, 13izentrie u n d Holokinetie.

Karyotypes of Southeastern Turkish Scorpions Hottentotta saulcyi and Buthacus macrocentrus (Scorpiones: Buthidae)

“…Although there are several faunistic and taxonomic studies on the genus Hottentotta, there is a paucity of cytogenetic studies. Chromosomal data are known for only three of the total of 51 currently recognized species of the genus Hottentotta species (10), were included in cytogenetic studies (11)(12)(13)(14)(15). Hottentotta tamulus species possesses 2n=22, 24 or 20-28 chromosomes forming a continuous series (12)(13)(14).…”

“…Chromosomal data are known for only three of the total of 51 currently recognized species of the genus Hottentotta species (10), were included in cytogenetic studies (11)(12)(13)(14)(15). Hottentotta tamulus species possesses 2n=22, 24 or 20-28 chromosomes forming a continuous series (12)(13)(14). But, Venkatanarasimhiah and Rajasekarasetty (13) stated that the chromosome number of same species have 2n=23 stable chromosome number in India.…”

“…This genus comprises almost 51 species (10). H. judaicus (Simon, 1872) (11), H. tamulus (Fabricius, 1798) (12)(13)(14) and H. trilineatus (Peters, 1861) (15) have been analyzed in cytogenetic studies up to present day. Hottentotta saulcyi (Simon, 1880) was firstly recorded in Mardin (10) and then reported in Batman, Şırnak, and Hakkâri in Turkey (9).…”

Chromosome biology of the scorpionPalamnaeus sp

“…Based on the fact that the long axis of the anaphase chromosomes is parallel to the spindle axis and the presence of constrictions on the chromosomes, Srivastava and Agarwal (1961) have claimed that the chromosomes of Palamnaeus longimanus are monocentric. Venkatanarasimhaiah and Rajasekarasetty (1965) have considered the chromosomes of Heterometrus seaber and Heterometrus fulvipes to be monocentric and acrocentric based on the fact that the long axes of the anaphase-I chromosomes lie parallel to the main axis of the spindle. In the colchicine injected Palamnaeus swammerdami they have shown the presence of subterminal, submetacentric and metacentric constrictions at prometaphase-I.…”

“…Even though the cytology of scorpions is well documented, the architecture of the chromosomes, especially the nature of the kinetochore, has been highly controversial (Piza 1943(Piza , 1947(Piza , 1948(Piza , 1950(Piza , 1957Brieger and Graner 1943;Brieger and Kerr 1949;Sharma and Joneja 1959;Sharma et al 1959;Srivastava and Agarwal 1961;Guenin 1957Guenin , 1961Venkat~narasimhaiah andRajasekaxasetty 1964, 1965;Venkatanarasimhaiah 1965). All the previous workers studied the chromosomes in sectioned and squash materials.…”