. Bonner zoologische Beiträge : Herausgeber: Zoologisches Forschungsinstitut und Museum Alexander Koenig, Bonn. Biology; Zoology. 514 M. Baez & Thorpe niscent of the northers area occupied by Bischoff's G. g. eisentrauti (1982). How- ever, to the south the scalation continues to change gradually over space so that the central and southern area is occupied by the 6—8 and 4—6 range and the extreme 0—2 range is found in the area around El Medaño. It should be noted that the contours are not aggregated into a narrow band showing a sharp zone of transition between two racial categor
. Bonner zoologische Beiträge : Herausgeber: Zoologisches Forschungsinstitut und Museum Alexander Koenig, Bonn. Biology; Zoology. 514 M. Baez & Thorpe niscent of the northers area occupied by Bischoff's G. g. eisentrauti (1982). How- ever, to the south the scalation continues to change gradually over space so that the central and southern area is occupied by the 6—8 and 4—6 range and the extreme 0—2 range is found in the area around El Medaño. It should be noted that the contours are not aggregated into a narrow band showing a sharp zone of transition between two racial categories. Insofar at is goes the latitudinal pattern of geographic variation revealed in this study agrees with the north-south subspecies recognised by Bischoff (1982). However, the subspecies imply distinct racial categories, whereas this study reveals a more gradual, clinal, change. It should be remembered that the subspecies where largely based on colour pattern whereas this study is based solely on sca- lation. If the north-south differentiation is caused by primary differentiation of the populations in situ (Thorpe 1984 a) in response to current selection pres- sures, then different character sets can have different patterns in response to different selection factors. There are very distinct climatic differences between the north and south of Tenerife which makes such an 'ecological' cause for the pattern, feasible. On the other hand, the transition could be caused by secon- dary meeting of previously separate populations. If this is the case then it is. Fig. Í. Map of Tenerife showing latitudinal geographic variation in the scalation of G. galloti. The localities are indicated by open circles. The contours (levels 2, 4, 6 and 8) are based on the canonical variate scores expressing geographic variation in scalation on a 0 to 10 range (8—10 heavy shading, 6—8 medium shading. 4—6 light shading, 2—4 blank and 0—2 blank).. Please note that these images are extra
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