NEW SUBFAMILY AND GENUS ACHATINIDAE 



33 



distinguished. Pilbry & Cockerel (1933) reported seeing two 

 living specimens 'crawling about 5 feet up on the trunk of a 

 tree in the forest above Tshibinda at about 2100 m' in Zaire. 

 The largest collection of this species, including many alcohol 

 specimens, is to be found in Tervuren (MRAC). B. graueri is 

 the type species of the genus. 



Radulae and jaws 



D'Ailly (1896:69) was the first to describe and illustrate the 

 radulae of Callistoplepa shuttleworthi and C. barriana. Pilsbry 

 (1904:ix, xv) referred to d'Ailly's work but reproduced only 

 the illustration of the latter species. He also reported (p. 72) 

 that G. Schacko (1881) {nee 'Schako 1 ) found 'A pulchella has 

 ... a very small central tooth'. The present work shows 

 Schacko's specimen was therefore misidentified. Thiele 

 (1929:560) examined and illustrated in part the radula of C. 

 shuttleworthi. He also examined but did not illustrate the 

 radula of Leptocala mollicella and pointed out that the middle 

 tooth was a little smaller than the neighbouring teeth. Possi- 

 bly on the basis of this observation, he prophetically juxta- 

 posed 'Callistoplepa and Leptocala. More recently, Ortiz & 

 Ortiz (1959:47) also illustrate the radula of C. shuttleworthi, 

 but the focal plane of the microscope was apparently too low 

 and the configurations of the teeth are misleading. The 

 radulae in the present project were prepared according to the 

 recommendations of Solem ( 1972) and the emphasis has been 

 placed on the rachidian teeth and the adjacent laterals. 



Because the soft anatomies of the four callistoplepine 

 species are so similar, it was not surprising to find the radulae 

 of C. barriana, C. shuttleworthi and L. mollicella (Figs. 

 58-63) to be remarkably similar. This fact supported the 

 earlier decision to conserve intact the odontophores of the 

 two extant soft anatomy specimens of L. petitia. It is assumed 

 with confidence that the radula of this latter species is 

 essentially like the others. In those examined, all have bold 

 rachidian basal plates and a broad functional rachidian tooth 

 that is one-half to two-thirds the size of the adjacent lateral 

 teeth. A second type of tooth is found in the first series of 

 laterals, which similarly consists of broad, solitary meso- 

 cones, but with conspicuous laterally asymmetrical basal 

 plates. A third type of tooth arises in the second series of 

 laterals, wherein the mesocones angle increasingly more 

 mesad and small ectocones gradually arise. These merge 

 almost imperceptibly into a fourth type, the tricuspid margin- 

 als with minute irregular endocones, broad shorter serrate 

 mesocones, and increasingly reduced basal plates that no 

 longer contact the teeth posterior to them. The greatest 

 irregularity within and between specimens occurs in the 

 gradient between the bicuspid laterals and the tricuspid 

 marginals. Hence the following formulae (tooth numbers 

 from centre to right) are only approximate: C. barriana 

 C-3 1-55-84, C. shuttleworthi C- 17-28-49, and L. mollicella 

 C-19-28-66. 



The available radula specimens in only two of the five 

 Bequaertina species have produced an incomplete and some- 

 what confusing picture in this genus. The basal genital 

 systems of B. pintoi and B. graueri are fundamentally similar 

 - both reflecting affinities with the Zaire Basin subgenus 

 Achatina {sensu Bequaert, 1950). It thus was anticipated that 

 the radulae also would be similar. The radula of B. pintoi 

 (Figs. 64, 65), not surprisingly, was found to be of the same 

 type as that of Achatina craveni E.A. Smith, 1881 (Figs. 68, 

 69). Both have greatly diminished, essentially nonfunctional 



rachidian teeth that are almost concealed by the adjacent 

 laterals. And both have broad based, nearly tricuspid laterals 

 with angular ectocones, broad mesocones and endoconal 

 flanges. In addition, the mesocone column of each lateral 

 tooth directly contacts and supports the broad basal plate of 

 the tooth immediately posterior to it. It should be noted that 

 A. craveni, on the basis of its soft anatomy, belongs in 

 Bequaert's subgenus Achatina rather than where he has 

 placed it in his subgenus Lissachatina. The surprise came in 

 the radula of B. graueri (Figs. 66, 67), with its large functional 

 rachidian tooth, attenuated massive basal plates, more 

 restricted contact support between horizontal rows of teeth, 

 and an imperceptible gradient into the marginal teeth. Within 

 the genus, B. pintoi and B. graueri are at the conchological, 

 geographic and ecological antipodes. The known plasticity in 

 molluscan radulae suggests that undetermined different feed- 

 ing demands in dissimilar habitats have produced the con- 

 trasts in the radulae of these otherwise two closely related 

 species. B. graueri and B. fraterculus appear to be very 

 closely related conchologically. There is a question now 

 whether the radulae will support this assumption. In reality, 

 the relationships in Bequaertina will not be understood until 

 both the soft anatomies and radulae of B. fraterculus, B. 

 pellucida and B. marteli are known. Radula formulae: B. 

 pintoi C-^2-25, B. graueri C-59, A. craveni C-34-24. 



The castaneous callistoplepine jaw forms an unusually 

 broad middle section that quickly tapers on each side to about 

 half its width and curves inward at the ends into a collariform 

 structure. Its surface is featureless except for microscopic 

 horizontal growth increments best seen under transmitted 

 light. Measurements: C. barriana! x 1.3 mm, C. shuttlewor- 

 thi 1.5 x 0.6 mm, L. mollicella 1.7 x 0.4 mm. The illustra- 

 tion of Ortiz & Ortiz (1959:46) for C. shuttleworthi appears 

 excessively broad. 



The jaw of B. pintoi forms a light castaneous nearly uniformly 

 slender rainbow arc, 5.5 x 1.1 mm, with ca 36 irregularly placed 

 vertical ridges. In B. graueri the jaw forms a lower arc, 

 4.4 x 1.3 mm, with very obscure vertical lineations. 



The more slender jaw of A. craveni forms a fulvous, 

 somewhat depressed arc, 4.5 x 0.7 mm, with ca 35 fairly 

 uniformly distributed vertical riblets. 



Acknowledgements. Special thanks are given to the curators and 

 their assistants of 28 museums, and to three private collectors, all 

 individually referred to in the Acronyms - Institutional & Personal 

 Collections. I am especially grateful to Drs A.C. van Bruggen 

 (Rijksmuseum van Natuurlijke Historic Leiden), B. Verdcourt 

 (Royal Botanic Gardens, Kew), and W.F. Sirgel (Stellenbosch 

 University) for reviewing the manuscript and offering valuable 

 suggestions; and to Dr P.K.. Tubbs, Executive Secretary of the 

 International Commission on Zoological Nomenclature, for consulta- 

 tions on the Code. I am also indebted to many others who have 

 provided important assistance, among them: Donald B. Sayner, 

 Charlotte Ernstein and Virginia Childs of the Scientific Illustration 

 staff at the University of Arizona for photographs in Figures 27-42, 

 45-46, 52-57; the Photography Service staff of the British Museum 

 (Natural History) for photographs in Figures 23-26, 43-44, 47-51; 

 David L. Bentley of the Electron Microscope Facility, Division of 

 Biotechnology, and Professor Michael A. McClure, both of the 

 University of Arizona, for assistance in the SEM photographs; 

 Emilee M. Mead of the University of Arizona Teaching Center who 

 drew the map and prepared the photographic layouts; Yolanda 

 Baldonado Whigham of the U.A. Department of Ecology and 

 Evolutionary Biology for word processing; and my wife Eleanor who 

 has helped in countless ways. 



