FOREGUT ANATOMY OF CRASSISPIRINE GASTROPODS 



91 



Crassispirinae (Fig. 28b). However, another Australian species that 

 we sectioned, Antiguraleus howelli (Laseron), possesses a typical 

 mangeliinae anatomy and Powell (1966, fig. 138) also illustrates a 

 typical mangeliine radula for Antiguraleus murrheus (Webster, 1 906). 

 Our observations suggest that the mostly Australasian species, 

 currently assigned to the Guraleus group of genera (Antiguraleus, 

 Paraguraleus. Guraleus and Neoguraleus) (Powell, 1966) represent 

 at least two different subfamilies, and the whole complex is in great 

 need of critical revision. 



CRASSISPIRA and subgenera 



At present, the genus Crassispira is usually divided into eight 

 subgenera. Our phylogenetic analysis shows that Crassispira 

 (Crassispira) and C. (Striospira) form a monophyletic clade, but 

 species of the other subgenera appear at widely separated positions 

 on the cladogram (Fig. 33) and have different anatomies from 

 Crassispira s.s. Our results suggest that the subgenera of Crassispira 

 should be raised to full generic status, with perhaps a case for the 

 retention of Striospira as a subgenus. 



EPID1RONA 



This genus was assigned to the Crassispirinae by Sysoev (In: Taylor 

 et al., 1993) on the evidence of the radula of the type species 

 Epidirona hedleyi Iredale, 193 1 , which has teeth with the wishbone 

 form similar to many other species in the subfamily, with a robust, 

 pointed, major limb and a slender secondary limb (Powell, 1964, 

 plate 229; Powell, 1966, fig. 33). However, our studies show that 

 Epidirona gabensis has a radula with the wishbone teeth with the 

 form typical of the subfamily Turrinae, i.e. awl shaped and bifurcat- 

 ing in the proximal half (Fig. 18) . Similar teeth were illustrated by 

 Powell ( 1 966, fig. 32) for Epidirona nodulosa Laseron, 1 954. In our 

 phylogenetic analysis Epidirona gabensis was shown to be more 

 similar, despite some anatomical differences, to the outgroup 

 Gemmula deshayesii, rather than to the crassispirine species. 

 However, the type species, Epidirona hedleyi would seem to be a 

 crassispirine on the evidence of the radula, but we have no anatomi- 

 cal information to confirm this. 



Our conclusions are that Epidirona gabensis and E. nodulosa 

 should be classified within the subfamily Turrinae. Epidirona hedlexi. 

 the type species, is likely to be a crassispirine and reference to the 

 illustrations in Powell ( 1 964, plate 230) shows that it differs from the 

 other species on shell characters. A new generic name is necessary 

 for the Epidirona species which possess theTurrinae-type of radular 

 teeth, however, anatomical or at least radular studies of the other 

 species is desirable. 



TURRIDRUPA 



The systematic position of this genus has been uncertain. Powell 

 (1966; 1967) referred it to the Turrinae on shell characters, but his 

 illustration ( 1 967 fig. 300) of the radula of T. jubata would seem to 

 be a misinterpretation. Subsequently, Kilburn (1983) transferred 

 Turridrupa to the Clavinae (= Drilliidae), but later, on the basis of 

 radular characters (Turridrupa bijubata andcincta) concluded ( 1 988 

 p. 235) that Turridrupa was 'a primitive crassispirine clade.'. Addi- 

 tionally, one of the species, Turridrupa cerithina, was again on 

 radular characters, transferred to the genus Inquisitor, (Kilburn, 

 1988, p. 267). Unfortunately, the anatomy is known only for 

 Turridrupa bijubata which has a quadrate central tooth and wish- 

 bone marginals (Kilburn, 1988 fig. 40) which are of the clothes-peg 

 type similar to those of the Turrinae. Also, our phylogenetic analysis 

 shows that in anatomical characters, Turridrupa bijubata is more 

 similar to the outgroup Gemmula (Turrinae) and to Epidirona gab- 

 ensis than any of the Crassispirinae. We have not studied Turridrupa 

 cerithina which has a different shell morphology from other species 

 and may well be a crassispirinan. In conclusion, we think that 

 Turridrupa should be classified in the Turrinae, with T. cerithina 

 possibly in the Crassispirinae. 



CONCLUSIONS 



This detailed study of the anterior alimentary system of one sub- 

 family of conoideans has revealed an extraordinary diversity of 

 foregut configuration. It is uncertain whether so much variation 

 exists in other conoidean groups, for far fewer species have been 

 studied. However, preliminary evidence suggests that a similar 

 diversity of foreguts exists in the Raphitominae. Clavatulinae and 

 Terebridae (Taylor, 1990; Taylor et al., 1993; Sysoev & Kantor, 

 1995; Kantor & Sysoev, 1996). The anatomy of Conus has usually 

 been taken as being typical of the whole Conoidea, but its foregut is 

 in many ways rather underived (basal buccal mass, unmodified 

 rhynchodeal wall, no oesophageal loop, unmodified anterior venom 

 gland). In fact, Conus can be regarded as just one of many possible 

 foregut configurations found within the Conoidea. Virtually all the 

 organs of the foregut can vary in presence or absence, size and 

 position. Thus for example, the proboscis may be very long or very 

 short; the buccal mass may be situated near the tip of the proboscis, 

 at the base or to the posterior; much of the posterior rhynchodeum 

 may be able to evert thus forming an extended proboscis, or there 

 may be several of no sphincters in the buccal tube. Indeed, more 

 extreme conditions exist in the some species of Raphitominae and 

 Terebridae. where the venom gland, radula, salivary glands and 

 proboscis have been lost. This diversity of foregut structure of 

 conoideans likely reflects considerable variation in feeding behav- 

 iour and methods of prey capture. Unfortunately, apart from Conus, 

 few details are available for other conoidean taxa (Miller, 1989; 

 Taylor et al., 1993). 



Acknowledgements. We are grateful to Gary Rosenberg, Dick Kilburn, 

 Jim McLean. Philippe Bouchet, Ian Loch, Winston Ponder, Graham Oliver 

 and Marco Oliverio for the generous donation of some of the specimens used 

 in this study. Alexander Sysoev provided discussion and encouragement. 

 Brian Morton gave much logistic support for the collection of specimens in 

 Hong Kong. David Cooper expertly prepared many of the serial sections. Yuri 

 Kantor is grateful to the Royal Society for the air fare enabling him work in 

 London. 



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