Fig. 4 in Convergent evolution of two Silurian graptolites

Fig. 4. Silurian graptolites Testograptus testis (Barrande, 1850) (A, B) and Cochlograptus veles (Richter, 1871) (C–F) in direct comparison. Specimens from SB−E, 49 m, Snowblind Creek, Cornwallis Island. A. Fragment of specimen with pseudovirgula development, GSC34920; A1, stereopair showing isolated nema; A2, enlargement to show nema area, and infilling between pseudovirgula and nema. B. Stereopair of dorso−lateral view of specimen with free nema and subsequent development of rhabdosome via a pseudovirgula, GSC34921. (C–F) Cochlograptus veles (Richter, 1871); from CP98, 6.4 m, Cape Phillips, Cornwallis Island (C, F) and from CM3, 6.1 m, Cape Manning Cornwallis Island (D, E). C. Extremely well−preserved specimen, showing blunt−ended sicula and flexure; note well−developed rutellum, GSC34922. D. Ventro−lateral view of well−preserved specimen showing four complete thecae, GSC34923. E. Infrared image showing strongly curved sicula, GSC34924. F. Views of a specimen showing a pseudovirgula (arrows) and exceptionally long rutellum, GSC34925; F1, distal view enlargement; F2, SEM image; F3, infrared image.