NEW SUBFAMILY AND GENUS ACHATINIDAE 



17 



shell has less luster than in this latter species. This peculiar 

 microscopic sculpture on the upper whorls is determinative. 



Soft anatomy. Alcohol preserved specimens available 

 2/dissected 2. Congo Republic: MRAC 1/1; Zaire: MRAC 

 1/1. These apparently are the only such specimens extant. 

 Both had small body masses and were withdrawn far into 

 their thin shells because they were collected during the dry 

 season and were inadequately drowned before preservation. 

 However, most of the soft parts were successfully extracted 

 with only minimal damage to one shell. 



Body colour and texture as in L. mollicella. 



Upon exposing the reproductive tract (Fig. 14), the most 

 noticeable anatomical feature is that both the unusual hull- 

 shaped penis (P) and the large basal vas deferens (BVD) 

 show through the thin, nearly transparent, but substantial, 

 penis sheath (PS). Typical of the Callistoplepinae, the PS also 

 enshrouds the very short penial retractor (PR). As in L. 

 mollicella and Callistoplepa barriana, this latter inserts far 

 posterior on the large right columellar retractor (RCR). Also 

 conspicuous is the apparently inordinately long bipartite 

 apical vas deferens (AVD), with a nearly evenly broad 

 muscular basal portion and a thin-walled, somewhat undulant 

 apical portion. When the PS was cut vertically and the edges 

 pulled laterally, it was found to extend essentially to the base 

 of the P. In the first dissected specimen, from Lukula, Zaire, 

 the exposed, large BVD appeared out of proportion and 

 excessively deeply wedged into the ventral surface of the P. 

 Similarly, the navicular P, with its diagonal left ventrolateral 

 orientation, seemed enigmatically distorted. But the second 

 specimen, from Kayes, Congo Republic, ca. 180 km to the 

 north, had almost identical proportions and alignment, thus 

 essentially removing the suspicion that there had been exces- 

 sive distortion. The relatively thin penial wall of the first 

 specimen was cut along a midventral, vertical line. Immedi- 

 ately below the surface was a large, obstructing mass of penial 

 wall tissue whose angulate orientation could not safely be 

 explored. Consequently, in the second specimen, a diagonal 

 cut was made along the long axis of the oblong P. This 

 revealed in right ventrolateral aspect a comparatively huge, 

 somewhat compressed potato-shaped pilaster (PIL) attached 

 diagonally along nearly its full length ventrolaterally on the 

 inner basal penial wall, parallel to the adjacent crowded BVD 

 (Fig. 15). In essence, the wall of the basal half of the P was 

 hardly more than a thin, tight-fitting cover for the PIL. The 

 surface of the PIL and the inner wall of the P, similar to that 

 of L. mollicella, was covered with transverse, diagonal, 

 anastomosing rugae. Irregularities in the rugae revealed a 

 small basal aperture. Cutting basally into the 2.6 mm PIL 

 exposed the short basal-most BVD narrowing rapidly 

 through dense connective tissue to connect with this aperture. 

 Apically, the PIL is a solid mass of penial wall tissue. 

 Collectively, the relationships in these structures are reminis- 

 cent of those in C. shuttleworthi , particularly with respect to 

 the exposed BVD pushing ventrally far down into the par- 

 tially evaginated P (Figs. 4, 5). 



In this species the basal female conduit, externally and 

 internally, is much less gross than in L. mollicella. The vagina 

 (V) is a distinguishable, more slender porion of the conduit. 

 Similarly, the basal spermathecal duct (SD) is less muscular 

 and tends less to interject itself between PS and the free 

 oviduct (FO). However, the FO, muscular at the base and 

 thin-walled apically, is less robust yet comparatively more 

 prominent in this species. Although shown spread apart in 



Fig. 14 for clarity, the FO and basal SD are actually held 

 tightly together by many small, short muscle bands, probably 

 providing support for the SD at termination of copulation. In 

 that natural position, the clavate spermatheca (S) is attached 

 by thin muscle bands and connective tissue to the uterine 

 portion of the spermoviduct, well above the junction of AVD 

 and FO. The eggs are not known but are probably on a par 

 with those of L. mollicella. 



Type material. The holotype (monotypy) (Figs. 29, 30; 

 Table 4) in the Jousseaume collection in Paris (MNHN) was 

 collected by L. Petit. 



Type locality. At the mouth of the River N'toc, which 

 disappears in the Mayumba Lagoon, Gabon 3° 25' S, 10° 39' 

 E. 



Distribution. Gabon: type locality. Congo Republic: Sibiti 

 3° 41' S, 13° 21' E (SMNH), Kola 4° 03' S 1 1° 44' E (MRAC), 

 Kayes 4° 26' S, 11° 23' E (MRAC). Zaire: Lukula 5° 21' S, 13° 

 02' E (MRAC). All known localities are south of the Ogooue 

 River of Gabon. This species will probably be found in 

 Cabinda, Angola. 



Remarks. In addition to the holotype in Paris (MNHN), 

 there are only six known specimens of this species, five in 

 Tervuren (MRAC), collected by Dartevelle, and a single 

 specimen in Stockholm (SMNH). The explanation for its 

 apparent rarity probably rests in the fact that there has been 

 much less professional collecting in south coastal Gabon and 

 the Congo Republic than in Cameroon, where L. mollicella is 

 not a rarity. In this limited number of specimens extant, there 

 is a north to south gradient of more intense vermiculate- 

 granulate sculpture and reduced rhomboid pattern. If the 

 substantive differences in the soft anatomies had not been 

 known, this taxon might well have been assumed to be no 



^/UGANDA ,, 







ZIMBABWE / 



■ 



29.) 



Fig. 16 Distribution of Bequaertina. O = Bequaertina fraterculus , 

 % = B. graueri, □ = B. pellucida, ■ = B. pintoi, A = B. marteli. 

 Where possible, all localities were checked with the volumes of 

 the U.S. Board on Geographic Names. 



