PYGIDICRANIDAE

Popham, Edward J., 2000, The geographical distribution of the Dermaptera (Insecta) with reference to continental drift, Journal of Natural History 34 (10), pp. 2007-2027 : 2011-2014

PYGIDICRANIDAE

( Map 4 )

Of the seven genera of Pygidicraninae , Pygidicrana is restricted to South America, the genus Dacnodes mainly occurs in South America and Africa, while the other ve genera all occur east of India in South East Asia, the East Indies and Australia table 3). The Echinosomatinae comprise 36 species, 10 in Africa, three in

2012 Madagascar, Seychelles and 26 in the Oriental Region and East Indies. The distribution of these species resembles that of the Diplatyid subfamilies, but their absence from South America, may indicate a possible African origin for this subfamily.

The Anataelinae occur in the Canary Islands and Brazil (Sakai, 1996), the Challinae in Korea and north east China, while the Pygidicraninae are represented

South America by the genus Pygidicrana , the majority of species occur east Asia and the East Indies, except for the African genus Dacnodes . The Echinosomatinae are distributed from Africa through Madagascar, the Seychelles to south east Asia, the East Indies and New Guinea. In contrast, the Esphalmeninae is predominantly neotropical family, which has spread into the Caribbean area, whilst the few species in South Africa, probably arrived there before the Cretaceous opening of the southern Atlantic Ocean. The Blandicinae are restricted to south east Africa and Madagascar.

The occurrence of the genus Pygidicrana in South America indicates that the Pygidicranids like the Diplatyids are of neotropical cum Ethiopian origin, while the presence of some genera and species in the Oriental Region and East Indies, implies that this is a secondary evolutionary centre for this family. The occurrence of a small number of species of the genus Tagalina in the East Indies, New Guinea and the Solomon Islands probably explains the occurrence of this genus in Northern Australia.

The phylogenetic and geographical relationships between these taxa are summarized in ®gure 2. Taking the Pygidicranidae, Haplodiplatys and the Diplatyidae together, it is reasonable to assume, that even if they may not be a monophyletic group, they could have evolved from a common ancestor with a`blattoid’ neck and two penis lobes, which are folded forwards when not in use. Figure 2 and map 4 suggest that the Pygidicranidae arose in an area of north-west Gondwanaland. The occurrence of the Anataelinae in Brazil and the Canary Islands supports this view and that the present discontinuous distribution of this subfamilies due to the Cretaceous opening of the Atlantic Ocean. The Challinae of Korea and south east Asia occur on the northern edge of the distribution of the Pygidicranidae .

2014

Figures

MAP 4. Distribution of the Pyidicranidae.

FIG.2. A possible tree for the subfamilies of the`Pygidicranidae’.