18 



A.R. MEAD 



Table 4 L. petitia - Representative shells measurements. 



Greatest Aperture Last % 



Whorls Length Width Length Width whorl LW/L % W/L 



7 32.5 14.8 



6V2 30.9 14.2 



6'A 30.8 14.8 



6V2 29.0 13.7 



6 28.6 14.6 



6 23.9 12.3 



5 20.8 13.3 



14.3 7.5 21.5 66 45 N'toc 



(MNHN) 

 Holo* 



14.5 7.1 21.4 69 46 Sibiti 



(SMNH) 



13.9 7.2 21.3 69 48 Lukula 



(MRAC) 

 212.583 f 



14.0 6.5 20.1 69 47 Kola 



(MRAC) 

 196.340 



14.5 7.1 20.5 72 51 Kola 



(MRAC) 

 196.341 



11.6 6.0 16.4 69 51 Kayes 



(MRAC) 

 214.004 f 

 11.8 6.3 15.1 72 64 Kola 



(MRAC) 

 791.389 



Total specimens examined: 7. Sources: MNHN. MRAC, SMNH. 



more than a subspecies of L. mollicella, as Bequaert & 

 Clench concluded (1934b:273). This case is reminiscent of the 

 conchologically very similar but anatomically contrasting 

 Achatina reticulata Pfeiffer, 1845 and A. albopicta E.A. 

 Smith, 1878 (Mead, 1950:232). 



Jousseaume's illustration of the holotype is misleading 

 because the artist has shown the apex acuminate; actually, 

 the first and second whorls are noticeably larger, producing a 

 narrowly obtuse apex. 



Apparently neither Leonardo Fea (Germain, 1916) nor 

 Captain Vignon (Ancey, 1888) went far enough south in 

 Gabon to encounter true L. petitia. 



ACHATININAE 



Bequaertina new genus 



Thin, fragile, anomphalous, medium to large, ovate to ovate- 

 elongate shells, 40-80 mm in length. Spire tends to be 

 mammillate, apex obtuse. Aperture large, columella long and 

 slender, squarely or obliquely truncated. Whorls 6-6V2, rarely 

 7; second and third nepionic whorls sculptured; last whorl 

 ventricose, ca. 80% of shell length. Sculpture may be vari- 

 ously cancellate-granulate, lirate, malleate or nearly smooth. 

 Surface of shell lusterless; its abrasion reveals a brilliant inner 

 periostracal layer. An occasional specimen may show in the 

 periostracum of the lower whorls limited areas of an 

 extremely fine decussate micromesh, commonly seen in a 

 wide variety of achatinids. 



The generic characters in the soft anatomy are based on 

 features that are shared by the two available species - B. 

 pintoi (Bourguignat, 1889) and B. graueri (Thiele, 1911). 

 Because of the similarity in the basic anatomical pattern in 

 these two species, and because, on the basis of shell charac- 

 ters, each of the species represents a different dichotomous 

 group, it is felt that the following anatomical characters will 

 prove to be valid for the genus. 



The most prominent features of the genital system are the 

 long free oviduct, the apical vas deferens and the large, 



elongate sacculate spermatheca - all held in close juxtaposi- 

 tion by a distinct fascia. In contrast, the penis and penis 

 sheath are inconspicuous. The penis sheath enshrouds a short 

 basal portion of the long vas deferens. Without exception in 

 26 dissected specimens, the penial retractor inserts on or near 

 the diaphragm where the latter joins the mantle and the body 

 wall of the neck region. At the origin of the penial retractor, 

 muscle fibrils pass snugly over the apical penis and then fan 

 out into a network that covers the basal vas deferens and the 

 inner wall of the penis sheath, except for a limited smooth, 

 shiny zone on the approximately upper half of the left side. 

 Below this, the fibrils infuse intimately with the tissues of the 

 basal penis and penis sheath to create an ill defined section of 

 the male conduit that contains the penial atrium. This atrium 

 connects the lumen of the penis with the genital atrium. At 

 this level, abundant hypertrophied eversion muscle bands 

 obscure the genital atrium and its junction with the male and 

 female conduits. There is no pilaster or verge. 



The spermathecal duct is much shorter than the spermath- 

 eca and often sessile on the vagina. This significantly places 

 the spermatheca in a basal position with its usually attenuated 

 apex stretching to its connection by fascia to the junction of 

 the free oviduct and the apical vas deferens, well below the 

 spermoviduct. The hermaphroditic duct has in its midsection 

 an enlarged glandular structure of unknown function. The 

 ductules to the five hermaphroditic acini are inordinately 

 gross and highly convoluted. 



The eggs are covered with a hard calcareous shell and are 

 proportionately larger than those of Achatina, i.e. on a par 

 with those of Tholachatina (sensu Bequaert, 1950). There is 

 no evidence of ovo viviparity. 



The anterior aorta is on the floor of the diaphragm and 

 passes ventrally through the diaphragm to the sagittal myo- 

 septum in the haemocoele. The second largest vein in the 

 lung drains the region near the extreme left mantle and joins 

 the primary vein near the apex of the kidney. The large last 

 whorl of the shell allows for a highly vascularized left side of 

 the lung. The secondary ureter is completely closed. The 

 rachidian tooth of the radula is either slender and question- 

 ably functional or broad and about half the size of the 

 adjacent laterals. The jaw is narrow and broadly arcuate, 

 with many slender vertical ribs irregularly distributed. 



Six specimens of B. pellucida (Putzeys, 1898) and one of B. 

 marteli (Dautzenberg, 1901), as well as several of Achatina 

 craveni, have been found with a single, almost perfectly 

 circular hole, 0.6-4.0 mm in diameter, cut usually in the 

 dorsal part of the last whorl. These are thought to be caused 

 by bird pecks (Meredith, 1983a:25). 



The five species in this genus were place in the genus 

 Callistoplepa on the basis of similar shell characters: thin 

 shell, large aperture and a tendency to form a mammillate 

 spire (Pilsbry 1919, Bequaert & Clench 1934c). But as shown 

 in the Key to Subfamilies, a study of the internal anatomies 

 revealed major differences. Bequaertina reflects strongest 

 phylogenetic affinities to subgenus Achatina (sensu Bequaert, 

 1950), particularly with respect to the configuration of the 

 basal male conduit and to the fact that the spermatheca is 

 attached to the adjacent free oviduct and apical vas deferens 

 rather than to the spermoviduct. In Bequaertina, the apical 

 penis is free from the apical penis sheath and therefore can 

 evert independently, with the sheath following seriatim at 

 extroversion, whereas in subgenus Achatina the penis is 

 completely enmeshed in a dense network of muscle fibrils and 

 connective tissue that requires the penis and the sheath to 



