NEW SUBFAMILY AND GENUS ACHATINIDAE 

 Table 3 L. mollicella - Representative shells measurements. 







Greates 



Aperture 



Last % 







Whorls 



Length 



Width 



Length 



Width whorl LW/L % 



W/L 



6'/4 



39.8 



18.7 



17.5 



9.3 



27.7 70 



47 



Bitya 

 (BMNH) 

 Para L. m. 

 zenkeri 

 1908.6.3.2 



6'/2 



37.5 



17.7 



17.3 



8.9 



26.5 71 



47 



Ebalowa 

 (UMMZ) 



6»A 



35.8 



17.5 



18.4 



8.7 



26.5 74 



49 



Yaounde 

 (UMMZ) 



6V2 



33.3 



17.3 



15.9 



10.3 



23.4 70 



52 



Olounou 

 (MRAC) 

 796.850 



6 



30.5 



16.1 



15.6 



8.2 



22.3 73 



53 



Kribi 



(MRAC) 



795.638 + 



6 



30.0 



14.8 



15.0 



7.5 



21.4 71 



50 



Calabar 

 (BMNH) 

 Holo/L 

 s mil hi 



6 



26.7 



13.4 



12.8 



6.2 



18.9 71 



50 



Gabon 

 (BMNH) 

 Lect. A. 

 mollicella 



93.2.4.119 



6 



26.6 



14.0 



13.6 



6.9 



19.1 72 



53 



Bonjongo 

 (MRAC) 

 5315 PLec 

 A. 

 pulchella 



5'/2 



23.6 



13.1 



12.4 



6.6 



17.3 73 



55 



Gabon 

 (BMNH) 

 PLec A. 

 mollicella 

 93.2.4.120 



4% 



16.6 



10.4 



9.1 



5.0 



12.2 73 



63 



Nyong 

 (ZMUC) + 



Total specimens examined: 35. Sources: BMNH. IRSN. MNHN. MRAC. 

 NHMW. NMW, SMNH. UMMZ. ZMUC. 



and A. smithi (= L. mollicella) at the same time and indicated 

 for both that the locality was 'Calabar, Africa?' (4° 57' N, 8° 

 19' E). Both specimens were from the Cuming collection, in 

 which a number of other locality records from time to time 

 have been questioned or proven incorrect. J.C. Reid of the 

 University of Calabar has collected near Calabar what is now 

 confirmed as Callistoplepa barriana, but so far no L. molli- 

 cella. It is altogether possible that this latter species eventu- 

 ally will be found in Nigeria because Mbonge, Cameroon, a 

 known endemic locality for this species, is only ca. 70 km to 

 the southeast in a similar environment. Ortiz & Ortiz 

 (1959:26) have reported the western-most records for this 

 species from four localities on Fernando Poo Island ( = 

 Macias Nguema Biyogo) of Equatorial Guinea 3° 30' N, 8° 

 40' E. Seventeen locality records on the continent cluster in 

 the northwestern corner of Cameroon, with the extremes 

 being Mbonge 4° 33' N, 9° 05' E in the North, Molobo 4° 01' 

 N, 14° 19' E in the East, and Efulen 2° 42' N, 10° 30' E in the 

 South. Vignon through Ancey (1888:70) records this species 

 as being very rare in the forests of Gabon. It probably is not 

 found south of the Ogooue River. 

 In the specimens examined, there was a high direct correla- 



15 



tion between greater shell size and distance from the sea- 

 coast, e.g. the largest specimen seen in this study is from 

 Bitya on the river Dja, ca. 260 km from the coast 3° 01' N, 12° 

 22' E (BMNH no. 1908.6.3.2; Table 3). 



Leptocala petitia (Jousseaume, 1884) 



Figs. 29, 30 



Petitia petitia 



Jousseaume, 1884:172, pi. 4, fig. 4a, holotype, monotypy 



(non Chitty, 1857); Bequaert, 1950:138. 

 Achatina (Leptocala) mollicella petitia 



Pilsbry, 1904:73, pi. 34, fig. 15 (ex Jousseaume, 1884); 



Bequaert, 1950:138, pi. 58, fig. 4. 

 Leptocala mollicella petitia 



Bequaert & Clench, 1934b:273. 



Shell. Shell ovate-elongate, thin but not fragile; last whorl 

 shiny, upper whorls less so. Whorls 6V2— 7, moderately con- 

 vex. Spire slender conic; apex narrowly obtuse; sutures fine, 

 almost without irregularities. Last whorl expanding propor- 

 tionately to upper whorls, 70% of shell length (n=7); fourth 

 and fifth whorls subcarinate. Aperture elongate-oval, milky 

 within. Columella short, straight, transversely to obliquely 

 truncate. Outer lip thin, arcuate, joining the periphery at an 

 acute angle. Parietal callus minutely granular, shiny, concol- 

 orous. 



Shell ground colour is pale corneous. At the junction of the 

 fifth and sixth whorls, diffuse yellow-brown stripes 

 (0.3-0.5 mm wide) alternate with wide ground colour bands 

 (0.5-0.7 mm); these are approximately the same width on the 

 early whorls, but become slightly or much narrower, more 

 distinct and closer together on the last whorl, or nearly 

 disappear; they may be variously straight, diagonal or 

 rippled. 



The last quarter of the first whorl has nearly imperceptible 

 surface irregularities that originate close to the suture, where 

 they evolve into a series of closely packed crescentic lines. 

 They quickly multiply axially into five or six horizontal series 

 of short crescentic lines. These gradually fuse vertically to 

 form very narrow, crowded, thread-like, prosocline welts. A 

 fairly conspicuous diagonal line, near mid third whorl, marks 

 the end of the nepionic whorls. Near there, the welts become 

 superficially engraved with a vertically oriented, exceedingly 

 fine vermiculate-granulate sculpture, which is reminiscent of 

 the much coarser sculpture of Achatina (Tripachatina) 

 vignoniana Morelet, 1874. Gradually, the welts diminish and 

 the more sparce growth lines emerge, leaving the rash-like 

 microscopic sculpture to dominate. This is best seen in 

 subdued light at a low angle. The sculpture may diminish and 

 become more sparce between the third and fourth whorls, as 

 it does in the holotype, or it may continue at essentially the 

 same caliber until the fourth or fifth whorl. At a certain point 

 in the diminution, and if the light intensity is properly 

 adjusted, ghost-like, engraved spiral lines, here and there, 

 spaced as in L. mollicella, can be distinguished, especially 

 below the periphery, where the sculpture is somewhat 

 reduced in calibre. The sculpture may extensively obscure 

 these spiral lines and all but traces of a rhomboid pattern, or 

 it may become so sparce on the lower whorls as to allow the 

 sharp spiral lines to dominate. It is almost as if the 

 vermiculate-granulate sculpture were superimposed upon the 

 typical sculpture of L. mollicella in a variably decreasing 

 intensity from apex to base. As a result, the surface of the 



