NEW SUBFAMILY AND GENUS ACHATINIDAE 



retractor anterior to the retractor of the right optic tentacle; 

 penis permanently partially evaginated; vagina wider than 

 long. Cameroon, Gabon, Equatorial Guinea ('Grand Bas- 

 sam' locality is suspect) shuttleworthi 



Callistoplepa barriana (Sowerby, 1890) 



Figs. 23, 24 



Achatina barriana 



Sowerby, 1890:579, pi. 56, fig. 2; von Martens, 1891:30. 

 Ganomidos barrianum 



d'Ailly, 1896:70, pi. Ill, figs. 5-10 (egg), text fig. (radula). 

 Callistoplepa barriana 



Pilsbry, 1904-05:127, pi. 47, figs. 14-17 (egg), pg. ix fig. 2, 



pg. xv (radula, ex d'Ailly); Germain, 1909:90; Bequaert & 



Clench, 1934c: 114. 

 Ganomidus barrianum 



Boettger, 1905:170. 

 Callistopepla barriana 



Dautzenberg, 1921:98; Oliver, 1983:9 (syntype). 



Shell. Shell ovate-conic, very thin, fragile, translucent, 

 shiny. Whorls 6-6V4, rarely 6V2, moderately convex. The 

 second and third nepionic whorls are nearly straight sided, 

 but they immediately give way to postemergent rapidly 

 expanding whorls, producing a mammillate or submammill- 

 ate, broadly conic spire and a blunt apex. Shallow sutures 

 form a thin, nearly even line. Last whorl large, convex, 82% 

 of shell length, range for 4-6V2 whorls = 78-86% (n = 115), 

 swelling faintly outward directly below the suture in some 

 specimens. Aperture broadly ovate, nearly vertical, pale 

 milky within. Columella thin, slender, slightly to broadly 

 arcuate, concolorous, squarely to obliquely truncate, inner 

 rim rolled adaxially. Outer lip thin, nearly evenly arcuate; 

 joining the periphery at only a modestly acute angle; greatest 

 width is characteristically midway. Parietal callus scarcely 

 apparent in unweathered specimens. 



From apex to base, the shell ground collar is uniformly pale 

 fulvous. Superimposed on this, beginning imperceptibly in 

 the fourth whorl, are two narrow bands of slender yellow- 

 brown chevrons - one at the periphery, and a less distinct one 

 transected by the suture. The chevrons in close juxtaposition 

 have their apices oriented prosocline and are about as wide as 

 the space between them. Much thinner, more irregular, 

 paler, parallel sinuate stripes may join the two bands. Speci- 

 mens with the most conspicuous patterns may have a second 

 zone of thin, pale, transverse bands between the periphery 

 and the base of the shell. The peripheral pattern tends to fade 

 with increased growth. Some specimens may have present 

 only the sutural band, or a unicolorous last whorl, or an 

 entirely unicolorous shell except possibly for a slightly darker 

 transverse band laid down between growth periods. Any of 

 the whorls may be flecked with minute circular or elongate 

 white spots (usually ca 0.2-0.8 mm). These are irregularly 

 and sparsely dispersed, but are especially conspicuous within 

 the costae of the last whorl. Upon close examination, they are 

 seen to be a consolidated white powdery substance between 

 the two periostracal layers. Although some are associated 

 with shell injuries, their formation is apparently a natural 

 phenomenon contributing to cryptic coloration. 



The most apical portion of each nepionic whorl dips 

 abruptly at near-right angles adaxially to form a narrow 

 platform in which is embedded a strikingly uniform series of 

 minute shallow pits that fringe the suture. This ornamenta- 



tion is limited to the nepionic whorls and is the homologue of 

 the diagnostic grossly costate sculpture in the second nepionic 

 whorl of C. shuttleworthi. The first whorl is essentially 

 smooth. Short faint slender crescentic threads and granules, 

 oriented transversely but aligned spirally in irregular series, 

 gradually make their appearance in the second whorl. As this 

 sculpture becomes more organized, the spaces between the 

 several spiral series seem to form shallow spiral striae. Near 

 the junction of the third and fourth whorls, a sharp transverse 

 delineation marks the end of the nepionic whorls, at which 

 level the threads become more symmetrical and greatly 

 compressed, but retain their individuality. With continued 

 growth, the threads remain fairly distinct or become trans- 

 versely variously fused into costellae, which interrupt or 

 obliterate in part the shallow spiral striae. Gradually the 

 threads become more bold and evolve into slender, closely 

 and very evenly placed prosocline corrugations or costae, 

 commonly with splitting and anastomosis. The spiral striae 

 remain superficial, barely transecting the costae. The 

 depressed cancellate sculpture below the periphery of the 

 upper whorls gradually becomes more corrugate until an 

 essentially uniformly costate sculture is finally formed on the 

 entire forward last whorl of the fullgrown specimen, dimin- 

 ishing slightly toward the columella and obliterating the 

 peripheral line of demarkation. The smallest shells may be 

 vaguely subcarinate. 



Soft anatomy. Alcohol preserved specimens available 

 31/dissected 13. Nigeria: BMNH 1/1; Cameroon: MRAC 2/2, 

 SMNH 10/4, SMF 14/6, UUZM 4/0. d'Ailly (1896) had access 

 to 34 alcohol-preserved specimens collected in Cameroon by 

 P. Dusen, Y. Sjostedt and J.R. Jungner. With the generous 

 assistance of Dr Ake Franzen, a diligent search was made in 

 the museums of Stockholm and Uppsala in 1987, but only 14 

 specimens could be found. There was no evidence of Jungn- 

 er's specimens. 



The body of the preserved specimen is uniformly grey 

 fulvous, without any apparent markings. Immediately poste- 

 rior to the shell, there is a depressed plateau that is fringed by 

 two prominent dorsolateral ridges, each composed of 12 

 closely aligned, truncate incisor-shaped elevations. 



The most unusual feature of the internal anatomy of this 

 species is the penis sheath (PS) (Fig. 1). Thickest at its base 

 (~0.5mm) it diminshes apically to a diaphanous facia 

 (~0.05 mm) that, in the normal position, enshrouds the 

 apical penis (P), the most basal part of the vas deferens 

 (BVD), and the basal portion of the extraordinarily short 

 penial retractor (PR). As in other achatinids, the origin of the 

 PR marks the division between P and BVD. In contrast to 

 that in C. shuttleworthi, the PR inserts on the right columellar 

 retractor (RCR) posterior to all other branches (Fig. 2). In 

 the fully mature specimen (Fig. 1) the tapering attenuated 

 apical P appears to be cramped into a sigmoid fold in this 

 thinnest apical PS. A dense webbing of muscle and connec- 

 tive tissue fibrils, originating from the PR, obscures, 

 entangles and foreshortens the apical folds of the P, even to 

 the point in the oldest specimens where this tight, wooly mass 

 of fibromuscular tissue becomes histologically intimately 

 intermeshed with the substance of the apical penial wall. On 

 its outer surface, this cocoon-like network forms a smooth, 

 dense coating over the P that is completely free from the 

 equally smooth but very shiny inner surface of the PS, thus 

 allowing free movement between P and PS. Basally, where 

 the PS is thickest, this fibrous layer conversely becomes so 



