NEW SUBFAMILY AND GENUS ACHATINIDAE 



13 



The ancestral stock of the two closely related, remaining 

 species in this genus, L. mollicella and L. petitia, probably 

 became separated in fairly recent times by a vicariance event 

 - possibly the development of the Ogooue River. 



Because of the unique microsculpture and the somewhat 

 smaller shell aperture, Leptocala up until now has escaped 

 suspicion of being closely related to Callistoplepa. The genus 

 is limited to the southwestern portion of Lower Guinea from 

 northwestern Cameroon to far western Zaire. 



Key to Species 



Shell 6-6V2 whorls; spire conic; exceedingly fine distinct 

 vertical and spiral lines form shallow minute engraved rhom- 

 boids. Pilaster verge-like, cylindrical, vertically suspended 

 from the apex of a dome-shaped penis; basal vas deferens 

 obscured by penial retractor. North of Ogooue River in 

 Gabon, Equatorial Guinea, Cameroon and probably south- 

 eastern Nigeria mollicella 



Shell 6V2-7 whorls; spire slender conic; exceedingly fine 

 closely appressed vertical vermiculate-granulate sculpture 

 obliterates the spiral lines, especially on the upper whorls. 

 Pilaster potato shaped, somewhat compressed, attached for 

 nearly its full length along a diagonal right ventrolateral axis 

 of a hull shaped penis; basal vas deferens conspicuous in 

 ventral view. South of Ogooue River in Gabon, Congo 

 Republic, western Zaire and probably Cabinda, Angola- 

 petitia 



Leptocala mollicella (Morelet, 1860) 



Figs. 27, 28 



Achatina mollicella 



Morelet, 1860:189; Pfeiffer, 1868:216; 1877:275; Vignon 



(in Ancey, 1888:70); Pilsbry, 1904:29. 

 Achatina pulchella 



von Martens, 1876:258, pi. 3, figs. 1, 2 (syntype) {non Spix 



& Wegner, 1827; non Pfeiffer, 1857); Ancey, 1888:70; 



Pilsbry, 1904:73, pi. 34, fig. 14 (ex von Martens). 

 Leptocala mollicella 



Ancey, 1888:70, 1898:92; Thiele, 1929:560; Bequaert & 



Clench, 1934b:273. 

 Achatina smithi 



Sowerby, 1890:579, pi. 56, fig. 3 (holotype, monotypy; 



non Craven, 1880). 

 Achatina sowerbyi 



E.A. Smith, 1890:392 (new name for A. smithi). 

 Petitia pulchella 



d'Ailly, 1896:71; Boettger, 1905:170. 

 Achatina (Leptocala) mollicella 



Pilsbry, 1904:73; Spence, 1928:213, pi. 2, fig. 5; Bequaert, 



1950:138; Zilch, 1959:366, fig. 1342. 

 Achatina (Leptocala) pulchella 



Germain, 1916:154, 241, pi. 6. figs. 11, 12. 

 Leptocala (Leptocala) mollicella 



Bequaert & Clench, 1934b:273. 

 Leptocala mollicella zenkeri 



Bequaert & Clench, 1934c: 118, pi. 1. figs. 5-7, pi. 2, fig. 



13 (holotype, 3 paratypes). 

 Leptocala mollicello zenkeri 



Bequaert & Clench, 1934c:119 (lapsus calami). 

 Achatina (Leptocala) mollicella petitia 



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

 Achatina (Leptocala) mollicella zenkeri 



Bequaert, 1950:138. 

 Leptocala pulchella 



Ortiz & Ortiz, 1959:25, pi. 5, fig. 99. 



Shell. Shell obovate, glossy, translucent, thin but sturdy; 

 periostracum tenaceous. Whorls 6-6V2, moderately convex. 

 Spire conic; apex broadly obtuse; sutures moderately deep, 

 fine, straight or slightly irregular. Last whorl expanding at a 

 somewhat greater rate than the upper whorls, 72% of shell 

 length, range for 4 3 /4-6>/2 whorls = 69-75% (n=34). Aperture 

 elongate inverted ear-shape, pale milky within. Columella 

 short, variably straight to slightly arcuate and twisted, trans- 

 versely to obliquely truncate, basal crest slightly elevated in 

 juvenile specimens. Outer lip thin, joining the periphery at a 

 broadly acute angle. Parietal callus minutely granular, shiny, 

 concolorous. 



Shell ground colour is pale fulvous, rarely somewhat 

 darker. Most specimens have a distinct but subdued pattern 

 of pale yellow-brown, slender, strongly parallel, nearly 

 straight or somewhat sinuous stripes, usually 0.2-0.3 mm 

 wide, alternating with ground colour bands of about the same 

 width. The banding may be slightly coarser and more con- 

 spicuous in the fifth whorl and above. Often apparently 

 unicolorous or weathered specimens under proper lighting 

 and magnification will be seen to have this characteristic 

 pattern at least in limited areas. This is witnessed in Bequaert 

 & Clench's (1934c) figure 7 of their Leptocala mollicella 

 zenkeri, which they report is 'without any darker markings'. 



The first I-IV2 whorls are smooth and very shiny. Short 

 vertical or arcuate lines begin to appear in the second whorl, 

 often concentrated at the suture below. These soon elongate 

 into delicate, narrow, closely packed vertical lines that span 

 the full width of the whorl. At 2 ] k whorls, there is a 

 conspicuous diagonal demarkation between the nepionic and 

 the postemergent whorls. At this demarkation, spiral lines 

 that immediately previous to this were sparce, short and 

 ghost-like, quickly form 35^40 nearly evenly spaced exceed- 

 ingly shallow, but sharply engraved lines. These lines cross 

 the vertical lines and cut the surface into minute engraved 

 rhomboids (see Bequaert & Clench, 1934c fig. 13). In the 

 following whorls, these spiral lines become more numerous 

 and somewhat wavy, suggesting the surface had been evenly 

 and shallowly combed. Beginning at 2'/2 whorls, subtile 

 prosocline, more sparce growth wrinkles compete with the 

 vertical lines; these may impact the suture directly or arcu- 

 ately. There is little reduction in the intensity of this engraved 

 pattern below the periphery, although there is a slight reduc- 

 tion in caliber. In the last half of the last whorl, the rhomboid 

 pattern may essentially disappear, leaving the growth 

 wrinkles to dominate. Throughout, the shell characteristically 

 remains remarkably smooth and shiny. A subcarina is present 

 in the early whorls, but this disappears in the fifth whorl. 



Soft anatomy. Alcohol-preserved specimens available 

 12/dissected 4. Cameroon: MRAC 3/3, UHZI 1/0; ZMB 7/0; 

 ZMUC 1/1. 



Body colour of preserved specimens, including the head 

 and anterior edge of the mantle, is pale-cream fuscous. 

 Dorsally, there is a diffuse grey wash that shades darker 

 anteriorly. A 1-2 mm wide dark gray band with diffuse 

 borders, appears immediately behind the ommatophores and 

 extends posteriorly along the middorsal neck to the edge of 

 the mantle. Surface of body reticulate-microtuberculate. Foot 

 without structural elaborations. 



