NEW SUBFAMILY AND GENUS ACHATINIDAE 



Remarks. This species is commonly encountered in collec- 

 tions and often confused with immature Achatina bandeirana 

 Morelet, 1866 and A. craveni E.A. Smith, 1881, both of 

 which have a proportionately much smaller last whorl. 



Callistoplepa shuttleworthi (Pfeiffer, 1856) 



Figs. 25, 26 



Achatina shuttleworthi 



Pfeiffer, 1856:34, 1859:603, 1868:216, 1877:275. 



Callistoplepa shuttleworthiana 

 Ancey, 1888:69. 



Ganomidos shuttleworthi 



d'Ailly, 1896:69, pi. 3, figs. 11-14, text fig. (radula). 



Callistopepla shuttleworthi 



Ancey, 1898:92; Thiele, 1929:560, fig. 644 (radula). 



Callistoplepa shuttleworthi 



Pilsbry, 1904-05:127, pi. 47, figs. 18-20, pg. xv (radula, ex 

 d'Ailly); Germain, 1909:90, 1916:248, pi. 10, fig. 4; 

 Bequaert & Clench, 1934b:114; Ortiz & Ortiz, 1959:45, pi. 

 5, figs. 97, 98, text figs. 28-31 (genit. syst., pallial com- 

 plex, jaw, radula); Zilch, 1959:373, fig. 1352. 



Ganomidus shuttleworthi 

 Boettger, 1905:170. 



Shell. Shell elongate-ovate, extremely thin, very fragile, 

 translucent with a subdued gloss. Whorls 5'/2-5 3 /4, rarely 6, 

 noticeably flattened in profile. A somewhat restricting, 

 deeply cut second nepionic whorl produces a mammillate 

 obtuse apex. The following whorls form a slender conic spire 

 as they descend more rapidly than they expand. Sutures 

 between nepionic whorls are deep and regular; those between 

 postemergent whorls are more shallow and only slightly 

 irregular. Last whorl subcarinate, noticeably so in juvenile 

 specimens, expanding proportionately, 77% of shell length, 

 range for 4'/2— 6 whorls = 73-83% (n = 60). Aperture 

 oblique-ovate, external colour pattern sharp and distinct 

 from within. Columella usually straight, axial, rarely slightly 

 arcuate, inner rim erect with a cord-like thickened crest; 

 truncation oblique to very oblique, rarely at right angles. 

 Between the third and fourth whorls, the crest of the col- 

 umella rolls abaxially on itself to form a hollow tube, there- 

 fore an open umbilicus. Between the fourth and fifth whorls, 

 this tube narrows and solidifies to form a slender axial cord, 

 which is seen in the full grown shell. This series of changes, 

 from open to closed, enigmatically has been observed in 

 several disparate achatinid species, e.g. A. achatina (Linne, 

 1758) and Archachatina spp. Outer lip of shell thin, skewed 

 basally, joining the periphery at an acute angle; greatest 

 width below midway; this is emphasized by the subcarinate 

 nature of the shell. Parietal callus thin, vague. 



Shell ground colour is pale corneous. The first 2'/i whorls 

 are unicolorous. Starting near the third whorl, vague round- 

 ish, very pale castaneous spots appear both at the suture and 

 periphery. At these two levels, the spots quickly assume 

 sharply angulate prosocline arrow-shaped patterns, high- 

 lighted with a series of parallel transverse elongate white 

 flecks. Similar flecks, reminiscent of those in C. barriana, are 

 scattered irregularly over the shell above the periphery, 

 rarely below. Soon the sutural band fractionates and moves 

 increasingly into a subsutural zone. The large arrows at the 

 periphery become spirally closely juxtaposed to form an 

 essentially continuous dominating colour band. From it, 

 slender, nearly parallel light castaneous stripes pass sinuously 



to the subsutural band and transversely to the columella. 



Only rudimentary costae appear in the last part of the 

 otherwise smooth first whorl. The entire second whorl is 

 conspicuously and uniformly ribbed from suture to suture 

 with elevated, deeply cut, nearly orthocline, gross costae, ca 

 0.2 mm wide (cf Germain, 1916 pi. 10, fig. 4). In the third 

 whorl the now more prosocline costae are soon reduced to 

 half their width. At midway in this whorl, an interruption in 

 the alignment of the costae marks the end of the nepionic 

 whorls. Gradually the costae become wider and finally regain 

 their original width in the fifth whorl, only to become 

 narrower and somewhat irregular in the last part of the sixth 

 whorl. Faint shallow closely spaced spiral lines, starting in the 

 second whorl, almost imperceptibly transect the prominent 

 costae. There is a delicate, greatly suppressed cancellate- 

 granulate sculpture on a vitreous surface below the periphery 

 in the upper whorls. This is invaded by the costae in the sixth 

 whorl until the entire whorl from suture to columella is nearly 

 uniformly costate. No splitting or anastomosis of the costate 

 has been observed. 



Soft anatomy. Alcohol preserved specimens available 

 12/dissected 5. Cameroon: SMNH 5/2, UUZM 7/3. All 

 specimens were collected by Y. Sjostedt. The only two extant 

 mature specimens were found by A. Franzen in a medical 

 laboratory at UUZM. d'Ailly (1896) reported having access 

 to 11 alcohol preserved specimens, which apparently did not 

 include Sjostedt's Itoki specimens that were available in the 

 present study. 



Body colour as in C. barriana; spade-shaped elevations on 

 the posterior foot only slightly less prominent. 



Without having dissected and deciphered first the relatively 

 more simple reproductive tract of C. barriana, it would have 

 been very difficult to interpret the relationships of the genital 

 structure in this species. In essence, the axis of the basal male 

 conduit has been greatly foreshortened telescoping the 

 homologous structures to such and extent that the pilaster 

 (PIL) on the ventral wall of the penis (P) is pivoted 180°, 

 forcing the junction of the P and basal vas deferens (BVD) 

 deeply into the dorsal aspect of the infolded P, i.e., the upper 

 ventral wall of the P and the most basal part of the BVD are 

 therefore seen only in the dorsal or lateral views (Figs. 4, 5). 

 A dense network of muscle and connective tissue fibrils 

 firmly fixes the structures in this permanently partially evagi- 

 nated position. This places the aperture of the BVD and the 

 contiguous subapical part of the PIL into a basal position 

 within the folded penial wall to take the lead in forming the 

 intromittent organ at extroversion. The inner smooth shiny 

 surface of the extremely thin-walled penis sheath (PS) facili- 

 tates seriatim extroversion: PIL-P-PS and finally genital 

 atrium, with the BVD and the attenuated penial retractor 

 (PR) contained axially within the intromittent organ. Figures 

 6, 7, 8 show at progressively deeper levels of dissection these 

 relationships from the ventral view. Both PIL and the inner 

 penial wall are confluent with a deeply rugate epithelium. It 

 should be noted that since the BVD opens directly into the 

 lumen of the penial chamber rather than passing through the 

 accessory organ to open at its apex, a pilaster rather than a 

 verge (penis papilla) is formed. 



The PR is extremely short and, as in the other species of 

 Callistoplepinae, it and the BVD are held tightly together by 

 the PS apical to the completely enclosed P (Fig. 9). In 

 contrast to that in C. barriana, the PR inserts on the right 

 columellar retractor (RCR) anterior and strongly ventral to 



