A.R. MEAD 



tance phylogenetically because this structure is well known to 

 be responsive to changing feeding habits within closely 

 related species. The wide, functional rachidian tooth immedi- 

 ately distinguishes the Callistoplepinae from most Achatini- 

 nae (Fig. 58-63). D'Ailly (1896:69) was the first to examine 

 and illustrate the radulae of both species of Callistoplepa (see 

 also Pilsbry, 1904:ix,xv; Thiele, 1929:560 and Ortiz & Ortiz, 

 1959:46). In the present study, the radulae of C. barriana 

 (Sowerby, 1890), C. shuttleworthi (Pfeiffer, 1856) and Lepto- 

 cala mollicella (Morelet, 1860) were found to follow the same 

 basic form and pattern. Similarly all the jaws are essentially 

 identical - simple, nearly smooth, fulvous, chitinoid collari- 

 form band that is somewhat wider in the middle and tapering 

 at the sides. There is no suggestion of even generic difference 

 in these structures. Thus, with only two alcohol specimens of 

 L. petitia (Jousseaume, 1884) extant, a decision was made to 

 leave their odontophores intact. 



All four species in the Callistoplepinae are limited geo- 

 graphically (ca 5° N-5° S) to the tropical Lower Guinea 

 region of West Africa, which at this point appears to be the 

 cradle of the Achatinidae (Mead, 1992). The high natural 

 luster of their translucent, elongate-ovate shells probably 

 reflects selective advantage in the protractedly wet rainforest. 

 Prior to the present study, the soft anatomy had been 

 examined in one or more species in the eleven achatinine 

 genera except the Guinean genus Columna (none so far 

 available) and all except four of the thirteen achatinine 

 subgenera (sensu Bequaert, 1950). All that have been exam- 

 ined clearly are anatomically more advanced than the two 

 callistoplepine genera. 



The calcareous, thick-shelled eggs are comparatively large 

 for the family and are on a par with those of Tholachatina. 

 D'Ailly (1896:68) felt they were somewhat small compared to 

 the size of the snail shell. Thiele (1929:560) echoed this point; 

 but d'Ailly apparently was comparing them with the rela- 

 tively huge eggs of some Archachatina and the subulinids. A 

 reticulate-microtuberculate texture covers the slender, 

 attenuated body. Basally, the mantle is generously covered 

 with variable size, fusing black to gray spots; these show 

 through the thin shell. Apically, the spots are smaller, more 

 regular and concentrated on the shoulder of the whorls. The 

 genital orifice appears to be unusually far posterior; Ortiz & 

 Ortiz (1959) made this observation in C. shuttleworthi. 



Typical of the known achatinids, the anterior aorta in the 

 Callistoplepinae is found on the dorsal surface of the dia- 

 phragm where it abruptly penetrates the diaphragm to pass 

 vertically along the anterior edge of the sagittal myoseptum. 

 Anteriorly, this latter separates the right and left columellar 

 retractors and incompletely places the male and female basal 

 conduits in left and right chambers, respectively. In all four 

 species, the triangular kidney is long, 2-3 times the length of 

 the pericardium, and sigmurethrous. The ascending limb of 

 the urethra is closed for its entire length. Venation of the lung 

 is a dense, broad network on the pericardial side of the 

 slender principal vein, whereas on the right of the principal 

 vein there is a relatively narrow band of parallel, limitedly 

 branching veins between it and the ascending limb of the 

 ureter. The second largest vein, about half the caliber of the 

 principal vein, starts as a network in the far left posterior 

 corner of the lung, anastomoses, and joins the principal vein 

 at a right angle 5-7 mm anterior to the kidney. 



Together, the four included species in this subfamily mani- 

 fest seriatim, from simple to complex, an impressive transi- 

 tion series in the basal male conduit from what surely is a 

 pilaster to that which appears to be a verge or penis papilla. 

 Callistoplepa barriana is the most primitive with an elongate, 

 elevated pilaster on the ventral penial wall. In C. shuttlewor- 

 thi the apical penis has permanently partially evaginated, 

 pulling dorsally the basal-most part of the vas deferens into 

 the pilaster and fixing it in place with tissue derived from the 

 adjacent penial retractor. This progression is taken one step 

 further in Leptocala petitia, wherein the permanently evagi- 

 nated apical penis becomes so greatly enlarged, thick-walled 

 and dorsoventrally distorted that the resultant pilaster essen- 

 tially fills the thin-walled, saccular basal penis. Finally in L. 

 mollicella, the pilaster assumes an apical position wherein it is 

 axially pendulous within the thick-walled basal penis. At first 

 glance, it appears to be a penis papilla, but the asymmetry 

 within betrays the fact that it is in actuality a greatly modified 

 pilaster. In all four species, the penial retractor is extremely 

 short and inserts on the right columellar retractor. In C. 

 shuttleworthi it inserts forward near the other branches; in the 

 other species it inserts far to the rear. The penis sheath is so 

 thin that it is difficult to trace; but it naturally enshrouds the 

 entire penis, allowing the penial retractor and the vas defer- 

 ens to pass out apically through the aperture of the sheath. A 

 barely discernible transparent tissue layer attached directly 

 on the surface of the penis is formed by the penial retractor. 

 This may be the forerunner of the condition found in some 

 Angolan achatinids, e.g. Achatina welwitschi Morelet, 1866, 

 in which the penis is buried in dense muscle tissue extending 

 from the penial retractor. Both the inner surface of the penis 

 sheath and the adjacent but continuous outer surface of the 

 penis are smooth, shiny and free from each other. This 

 condition facilitates seriatim extroversion. 



The spermatheca is consistently attached to the spermovi- 

 duct well above the junction of the apical vas deferens and 

 the free oviduct. In the adult forms, there is no distinct 

 vaginal retentor between the vagina and the body wall. In 

 juvenile specimens of C. shuttleworthi, however, the anlage is 

 present, which suggests that in this subfamily, its full develop- 

 ment may be obviated by the highly developed, muscular 

 basal female conduit. 



Type genus: Callistoplepa Ancey, 1888. 



Key to Genera 



Sculpture of body whorl coarse, with slender, tightly and 

 evenly placed prosocline costate ridges; shell aperture large, 

 usually 52% of shell length; last whorl long, usually > 73% of 

 shell length. Posterior foot with dorsolateral serrate ridges. 

 No colored band on neck. Equatorial Guinea to Nigeria- 



Callistoplepa 



Sculpture of body whorl with extremely finely engraved 

 microscopic rhomboids or vertical vermiculate granulae; shell 

 aperture modest, usually > 52% of shell length; last whorl 

 shorter, usually > 73% of shell length. Foot without dorsolat- 

 eral ridges. Dark gray band on neck between ommatophores 

 and mantle. Cameroon to western Zaire Leptocala 





