UNIVE*SIT¥ OFFfLORIDA Gaine-sville 1970-1971 BULLETIN OF THE FLORIDA STATE MUSEUM BIOLOGICAL SCIENCES Volume 15 Number 5 SOME MEXICAN LAND SNAILS OF THE GENERA COELOSTEMMA AND METASTOMA (UROCOPTIDAE) Fred G. Thompson - UNIVERSITY OF FLORIDA Gainesville 1971 Numbers of the BULLETIN OF THE FLORIDA STATE MUSEUM are pub- lished at irregular intervals. Volumes contain about 300 pages and are not necessarily completed in any one calendar year. OLIVER L. AUSTIN, JR., Editor WALTER AUFFENBERG, Managing Editor FRED G. THOMPSON, Assistant Editor Consultant for this issue: WILLIAM J. CLENCH Communications concerning purchase or exchange of the publication and all manuscripts should be addressed to the Managing Editor of the Bulletin, Florida State Museum, University of Florida, Gainesville, Florida 32601. Published 27 April 1971 Price for this issue $ .50 SOME MEXICAN LAND SNAILS OF THE GENERA COELOSTEMMA AND METASTOMA (UROCOPTIDAE) FRED G. THOMPSON1 SYNOPSIS: The following new taxa are described: C. letic<,3/o,na n. sp,, C, bembix n. sp., C. cclipey n. sp., C. ailachts/a n. sp„ C richardi n. sp., C. noinga.¥tor n. sp., C. astraxis n. sp., C. formix· n. sp. and C.'. fornax ix n. ssp. Two new subgenera are also proposed: Crit/co,y'le n. subg. (type species: C. (11/n,xis) and S/gic,p/!/x n. subg, (type species: C. formix): C. a,itricola Bartsch is reduced. to subspecific status as C. bottrgeni.yanci „,ilricolit. C. ci,ilphixi:i Pilsbry, type species of the subgenus Aper/axis, is synonymized with C. coa/juili'ji.%·is (Ba-rtsch). Metct.5/onm is elevated from a subgenus of //olospim to generic status and is closely related to Coe/ovent- 111( 1 . Aspects of the embryonic sculpture are determined for C , eliz.(11)e Iii( le (Pils - bry), C. b. bourgeoisana Bartsch, C. b. antricola Bartsch, C. iqualaensis (Bartsch), C. 11"ze/ae Pilsbry, C. flf.yca (Martens), C. con/mi/ensis (Bartsch) and 11 k /us/onic, roenic,·i (P.feiffer). These are features omitted in earlier descriptions of: these species. INTRODUCTION This is a preliminary report on some Mexican land snails of the genus Coelbstemnm. Discussions of their anatomies will be presented in a forthcoming paper on the phylogeny of the Mexican Urocoptidae. The descriptions of some new species of Coclostenima from southern Mexico require a review of the status of Metastonia. Code,stemina L elongs to the Holospirinae, a subfamily confined to Mexico, the southwestern United States, and a small area in Guatemala. About 17 genera and subgenera are recognized throughout this region, and undoubtedly additions will be made when the more poorly known 1Fred G. Thompson is Assistant Curator in Malacology, at the Florida State Museum. His research includes systematios, zoogeography, and ecology of land and freshwater mollusks. Thompson, Fred G. 1971. Some Mexican Land Snails of the Genera Coeins/£.ni- ma and Metastoma (Urocoptidae). Bull. Florida State Mus., vol. 15, no. 5, pp. 267-302. 267 268 BULLETIN FLORIDA STATE MUSEUM Vol. XV parts of Mexico are further explored. The genera and subgenera are dif- ficult to define, because their distinctions are based upon shell char- acters, some of which may be polyphyletic in derivation. Coe/o.9/.emma is recognized by its enlarged hollow axis. This character occurs in two other genera, Metastonm and A/locoryphe, and close relationshipk may exist between these groups. AckNOWLEDGEMENTS During the course of this study I have been aided by several people who have given me critical assistance. Angela Crane, British Museum (Natural History), provided me with measurements and photographs of the type series of Holospira fuscu Martens, which were necessary to restrict the name among two species in the type series. Joseph Rosewater, U.S. National Museum (USNM), loaned me the type series of Epirobiii Coahuile„Sis Bartseh so that aspects of its embryonic, sculpture could be determined. Gonzalo Halffter, Instituto Politecnico Nacional, Mexico, sent me specimens Of great interest and facilitated my field work through the assistance and courtesies of his office. Field work in Mexico was conducted with a collecting permit issued through the office of Rodolfo Hernandez Corzo, Direccion General de La Fauna Silvestre, Mexico. To all of these people I am grateful. Most of the material studied is deposited in the Flor- ida State Museum collections, University of Florida (UF). 3 Genus Coelostemum Dall Coclowemma Dall, 1895; Nautilus, 9: 50,- Pilsbry, 1900; Man. Conch,, II, 15: 98-99.- Bartsch, 1943; Jour. Wash. Acad, Sci., 33. 58.- Pilsbry, 1953, Proc. Acad. Nat. Sci. Phila., 105: 156. (Type species 6y original designation: //0/0- spirit clizt,betlitte Pilibry, 1889). Megaxh. Pilsbry, 1946; Land Moll, N. Amer,, 11(1): 123. (Type species by orig- inal designation: Holimpircifusca Maftens, 1897). The shell is dextral, cylindroid in shape, bears a large hollow axis and lacks any lamella within the aperture. Lamellae or other sculpture may be present on the axis. Coelostemnza consists offour subgenera. The typical and most wide- ly distributed subgenus has minute granular sculpture on the first two embryonic whorls fdlowed by fine vertical ribs on the last half embry- onie whorl. The second subgenus, Apertaxis, has only fine granular sculpture on the embgonic whorls. The two remaining subgenera have smooth embryonie whorls. They are localized in the same general re- gion in north central Mexico and probably have a common origin from a single Coe'lostentina ancestry. Coelostemina is most closely related to Metastoma. The large hol- low axis occurring in both genera contrasts strongly with the narrower, 1971 THOMPSON: MEXICAN LAND SNAILS 269 barely perforate axis of most other Holospirinae. This expanded axial eondition is approached in some species of the Holo.,·pira subgenus A/- locor!/Phe, but whether a close relationship exists between Coelostemnw and Allecoryphc is uncertain. The phylogenetic relationships within Holospira.5. 1. and Coe/ostcm,?ta are poorly established, and only ex- tensive field work in Mexico will clarify the relationships. Subgenus Coelostemnw Dall The typical subgenus has about two embiyonic whorls that are sculp- tured with minute granules, which on the last % embryonic whorl are, replaced by fine vertical threads or riblets. The axis is either smooth or has fine vertical threads and may bear a spiral swelling just above the floor of the whorls. The center of evolution of Coelostemma (5. s.) is in southern Mex- ico, primarily in Guerrero, Oa-xaca, and Morelos. It probably will be found extensively in Puebla and Michoacan with some species occur- ring in adjacent regions of Veracruz and Colima. My field experiences indicate the subgenus probably does not extend south of central Oaxaca. Some.species from northern Mexico are also referred to Coclos·/eni- ma (s.s.). Two species, C. marni Drake, 1951 and C. reitcri Drake, 1951, are known only from broken shells denuded of embryonic whorls, and their subgeneric allocation cannot be determined by embiyonie sculpture. The axis of C. greggi Drake, 1951 is very narrow, and the species herein is placed in Haplocion Pilsbry, 1902. These three species are from Chihuahua. C. fieutagi Bartsch, 1950, also from Chihuahua, C. clalli Pilsbry, 1902 and C . scilti //ensis Pilsbry , 1953 from Coahuila and C. Lissocentrum Pilsbry, 1953 from Nuevo Le6n are described as being typical for Coelostemnict (s.s.). Details ofthe embryonic sculpture for the last three species need to be confirmed. Coclostemma (s. 4.) consists of five or more groups of species, four - of Which are readily defined while others are less clearly delimited be- cause of limited material from southern Mexico, The typical group, consisting of C. elizid,ethcle and some other species from Guerrero and Oaxaca, has fine, oblique riblets on the axis and an opaque, livid-white shell of moderate or large size. A second group, consisting of C . hazelar and two new species, has a smpoth axis but is similar in other respects to the typical section . A third group, consisting Of C. bourgeoisana and its allies, has the fine, oblique ribs on the axis broken into serrations and granules. Another group of small brownish species from Oaxaca (C richardi and C. notogastor) has oblique riblets on the axis such as occurs in C. elizabet/me, but the snails' small size and their color pre- 270 BULLETIN FLORIDA STATE MUSEUM Vol. XV sent an appearance that is quite different from other species groups. Two other species, both of which have smooth axes, are similar in ap- pearance to this group and probably are derived from it. Coe/ostemina clizabethae (Pilsbry) Holospim elizi,bethae Pilsbry, 1889; Proc. Acad. Nat. Sci. Phila.: 81; pl. 3, figs. 1-5.- Crosse, 1892; Jour. de Conchyliologie: 272; pl. 5, figs. 6-6a,- Martens, 1897; Biol. Cent. Amer.: 635.- Pilsbry, 1903; Man. Conch., II, 15: 99-100; pl. 15, figs. 6-15; pl. 27, fig. 27. (Type locality: Amula, Guerrero). Holospira (Coclostemnut) elizabelhae Pdsbry, Dall , 1895; Naut., 9 : 50.- Dall , 1895; Proc, U. S. Nat. Mus., 19: 347,- Bartsch, 1906; Proc. U. S. Nat. Mus., 31: 149. Coch,.3/emma clizabe/hae (Pilsbry), Bartsch, 1943; Jour. Wash. Acad. Sci., 33: 58. 1101<,spir(, cl(loiformis von Martens, 1897 , Biol . Cent . Amen 277 ; pl , 16 , figs . 10-16. (Type locality: Amula, Guerrero). This species was collected from three places near the type locality. The samples show no variation not encompassed in eaflier descriptions by Pilsbry (1889, 1902). The embryonic whorls are low and are sep- arated by a relatively weakly-impressed suture. The firsttwo or so em- bryonic whorls are sculptured with fine granules. The following quarter whorl bears fine axial ribs that begin along the upper suture, become inereasingly intense, and grade into the coarser sculpture of the follow- ing post-embryonic whorl (Fig. 1, A). SPECIMENS ExAMINED.-GUERRERO:- 11.2 mi. E of Tixtia, 6506 ft. elev. (UF 20819); 7.7 mi. WSW of Chilapa, 6400 ft. elev, (UF 20820); 2.3 mi. WSW of Chilapa,-5300 ft. elev. (UF 20818). Coe/ostemina iqualacnsis (Baitsch) //0/0:·pira (Coclo,·tcmma) iclitaluensis· Bartsch, 1926; Proc. U. S. Nat. Mus., 70: 3-4, pl. 1, fig. 12. (Type locality: Iquala [Igualal, Guerrero). Coeloitenima iquciltiens·is (Bartsch), Bartsch, 1943; Jour. Wash. Acad. Sci., 33: 58. The material listed herein was collected from two localities that lie about 25 miles apart. Both samples demonstrate considerable intra population variation in shell dimensions (Table 1). The specimen illustrated (Fig. 1, F) has stronger vertical riblets on the embryonic whorls than is usual. The sculpturing is normal in all other aspects. SPECIMENS ExAMINED.-GUERRERO: - 7.7 mi. N of Tonalapa, 3400 ft. elev. (UF 20998); 5.5 mi. SW of Buenavista de Cudllar, 4100 ft. elev. (UF 20999). 1971 THOMPSON: MEXICAN LAND SNAILS 271 TABLE 1, MEASUREMENTS.(in mm) OF TWO POPULATION SAMPLES OF C, iqualaenis. Number Length Width Aper. H. Aper. W. Whorls 20998 (24) 19.1-29.0 6.8-7.9 4.3-4.8 4.2-4.5 16.8-21.9 20999 (40) 18.9-25.2 5.8-7.7 4.0-4.5 4.0-4.8 15.7-19.1 45Xji~.Frill -/ 0\ Pt\\=\~ /*V««» 1f~- n A B C A /rs· ··. 1 F-/'7\- AAr 9 r . .rD E F *f« , *'lili M"97. 7 .¥.lili Ati\\Jile< G HI FIGuRE . 1 . Apical sculpture of Coelosteninia . A. C elizabetlute (Pilsbry) ( UF 20891). B. C ec/ipcs new species (holotype), C, C. fused (Martens) (UF 20916). D. C. anaciasta new species (holotype). E , C. Benibix new species (paratype). F , C iqualite,mis (Bartsch) (UF 20999). G. ('. iaologastor new species (paratype). H. C. richurdi new species ( paratype ). I . C . h: iici ,stoma new species ( holotype) Coelostemnia bourgeoisana bourgeoisana Bartsch Coelostemma bourgeoisana Bartsch, 1942 ; Jour . Wash. Acad . Sci ., 32 : 187 ; fig, 1 .- 1943; ibid, 33: 58. (Type locality: Ixtapan de la Sal, Mexico). This snail is common on limestone terrain about the type locality and is a local variation of the more widely distributed antricola, with which all parameters of the shell intergrade (Table 2). Aspects of the embryonic sculpture of both subspecies are similar to those of C. iquu - le,ensis and other species from southern Mexico. 272 BULLETIN FLORIDA STATE MUSEUM Vol. XV TABLE 2. MEASUREMENTS (inmm) OF FOUR POPULATION SAMPLES(OF C. bourgeoisana. Subspecies No. Length Width Aper. H. Aper. W, Whorls bourgeoisana 21147 (136) 12.6-20.0 4.3-5.6 2.8-3.6 3.1,3.7 13.4-17.5 (intricola 21150 (50) 14 . 1 -25 . 1 4 . 8 -5 .6 3 .0 -4 .2 3 . 2 -3 .9 16.0 - 21 .8 anti ic(} 1( 1 21149 (45) 17 .0 -24 .9 4 .8 -5 . 5 2.9 -3 .8 3 . 0- 3 . 7 17 . 2 -21 .4 untricola 21151 (40) 18 .8 -25 .9 4 .9 -5 . 9 3 . 1 .-3 . 8 3.0-4 .0 17 .5 -22 .7 SPECIMENS ExAMINED.-MEXICO:- 0.5 mi. N of Ixtapan de la Sal, 6200 ft, elev. (UF 21148. 146), 0.5 mi. SW of Ixtapan de la Sal, 6500 ft. elev. (UF 21147.136). Coelostemina bourgeoisana antricola Bartsch Coelostemmu cintricohi Bartsch, 1943 ; Jour. Wash. Acad . Sci., 33 : 58 ; fig . 5 . (Type locality: ravine near Las Grutas, Cacahuamilpa, Guerrero). This subspecies previously was known only ftom two specimens collected at the type locality. N, SPECIMENS ExAMINED.-MEXICO:- 14.3 mi. SE of Tonatico, 4900 ft. elev. (UF 21149.45). GUERRERO:- 7.8 mi. NE of Taxco, 5800 ft. elev. (UF 21150. 50); 16.8 mi. NE of Taxco, 4200 ft. elev. (UF 21151. 40). Coelostemma leucostoma new species DIAGNOSIS.-A medium-sized cylindrical, ribbed species related to C. bourgeoi*ma because of the similar sculpturind on the axis in the two species. C. /eucostonia differs from C. b. bourgeoisand and C. b. antricola by its slender shape, more attenuate apex, and less strongly- arched whorls. SHELL (Fig. 2, A-E).-The shell is medium-sized (about 14-20 mm long), cylindrical, slender, and narrowly rimate or imperforate. The shell is dull, light tan and the inside of the,apertureis white. The apex is attenuate, consisting of about 9-10 hearly flat-sided whorls. The fol- lowing whorls are nearly uniform in diameter, deereasing slightly near the base. The aperture extends forward and laterally on a moderately- long neck. The neck is rounded on the base and slightly flattened over the parietal wall. Whorls 15.8-20.1 (19.8 in holotype). The suture on the apex and the cylinder is distinctly impressed though the whorls are 1971 THOMPS()N: MEXICAN LAND SNAILS 273 A B C - 0 E F FIGURE 2. (.2 )(' /0 3.t mm Ci /(, 11·C),i t, 3 n la new species. A. Hole,type. B-E. Paratypes. 274 BULLETIN FLORIDA STATE MUSEUM Vol. XV weakly arched. The embryonic shell consists of 2.2-2.5 whorls that are rounded and button-like, the second decidedly larger than the first. The first two embryonie whorls are sculptured with numerous fine granules, whieh are replaced on the last 34 embryonic whorl by fine regular ribs that become increasingly strong and grade into the coarser sculpture on the following apical whorls (Fig. 1, I). The apical ribs are almost uni- formly spaced and widest at the base, where they form white knobs. The ribs on the subsequent whorls are weakly arched, about as wide as their interspaces and lack basal knobs. There are about 35-47 ribs on the penultimate whorl (38 in holotype). The ribs become stronger and more widely spaced on the neck ofthe last whorl and extend around the base and into the umbilicus where they are finer and sharper. The aper- ture is nearly ovate in shape, being slightly Rattened dorsally. The peristome is moderately expanded around the aperture, being widest along the base and narrowest dorsally. The axis is about 34 the diameter of the shell, is.spindle-shaped within each whorl, and bears fine, oblique axial ribs that are weakly serrate. Length of shell 14.2-20.5 mm (19.6); width 4.0-4.6 mm (4.4); aper- ture height 2.7-3.0 mm (3.0); aperture width 2.9-3.4 mm (3.2). Meas- urements in parenthesis pertain to the holotype. TypE LocALITY.-Ruinas de Xochicalco, Morelos; 4900 ft. elev. HolmypE: UF 21145, collected 11 June, 1966 by Fred G. Thomp- Son. PARATYPES: UF 21146 (113); Dept. Zoologia, Instituto Politec- nico Nacional, Mexico (25); same data as the holotype. Snails were col- lected near the ruins from under limestone blocks over a caliche, The area contained submesic scrub and trees that were closely browsed 6y sheep. REMARKS.-This species is closely related to C. bourgeoisana~ It differs from the latter by its more attenuate apex, nodular ribs on the apex, and its Ratter whorls. Aspects of the apieal sculpture also sug- gest a relationship with C. richardi, described below. The two species are readily distinguished by their shapes and their axial sculpture. ETYMOLOGY.-The speciSc epithet is derived from the Greek leukos, meaning white, and stoma meaning mouth and refers to the white aperture in this species. Cocloste,nma hazelae Pilsbry Coehtstemmu haze/ae Pilsbry, 1953; Proc. Acad. Nat. Sci. Phila., 105-159; pl. 5, fig. 4. (Type locality: between Chilpancingo and Mazatlin, Guerrero). This species, previously known only from the holotype, is repre- 1971 THOMPSON: MEXICAN LAND SNAILS 275 sented by two series from near the type locality. Specimens from 2.2 mi. NNE of Mazatlin, Guerrero, 4800 ft. alt. (UF 20996) are similar to the holotype in most respects, though most individuals are slightly more slender (Fig. 3, A-C). Specimens from 3,4 mi. NNE of Mazatldn, Guerrero, 4700 ft. dt. (UF 20997) differ by being considerably shorter stockier, though of similar width to the holotype (Fig. 3, D-F). As in other species of Coelostemma from southern Mexico the em- A B C i.0.- 0 D E F FIGURE 3. (.i)<'/c).sti'mmci hco'/m' Pilsbry. A-C. 2.2 mi. NE M :1 zatlan, Guerrero. D-F. 3.4 mi. NNE Mazatlan, Guerrero. 276 BULLETIN FLORIDA STATE MUSEUM Vol. XV bryonic whorls are sculptured with minute granules on about the first two whorls. The following half whorl or so bears weak axial thread-rib- lets that grade into coarser riblets on the followingpostembryonic whorl. Coelostemma eclipes new species DIAGNosis.-A species distinguished by its moderately-large size (usually about 18-20 mm long), opaque, whitish color, subelliptical shape, costulate lower whorls, imperforate axis, moderate neck, and smooth axis. Beabuse of its smooth axis it is related to C. haze/ae and C. bembix, both of which occur in adjacent areas of Guerrero , C . ectil~es differs from C. haze/ae by its larger size, larger caliber whorls, costulate lower whorls, imperforate axis and longer neck behind the aperture. The neck also bears a basal impression that is absent in C. haze/ae. C. eclipes is distinguished from C. bembix by the numerous peculiarities ofthe latter species described below. SHELL (Fig. 4, A-E).-The shell is moderately large and stocky and is subeylindrical or elongate-elliptical in shape. The widest portion lies just below.the apical cone. The apex consists of about 7-8 whorls, is elevated, and is slightly convex in outline with protruding embryonic whorls. The shell is dull-white over most of the spire, with a dark gray apex. The umbilicus is imperforate. Whorls, 12.7-16.4 (16.4 in holo- type). The whorls are moderately-arched on the apex but are nearly flat on the spire. The 2.5-3.1 embryonic whorls (3.0 in holotype) are offset by a deeply-impressed suture (Fig. 1, B). The firsttwo embryonic whorls are sculptured with dense, minute granulati6ns. The subse- quent embryonic whorl bears strong, oblique riblets that are of the same intensity as those on the following postembryonic whorl. The first three postembryonic whorls bear oblique riblets that are about half the width of their intervals. The remainder of the apex and most of the spire are nearly smooth, with only irregular incremental striations. The last 2-3 whorls bear heavy, rounded ribs that are strongest 6n the last whorl. The aperture is extended forward from the body whorl for about. 2 mm. The neck is flattened dorsally and bears on its base a moderate, linear impression that forms a low callused ridge internally. The aperture is usually wider than high and is ovate-auriculatein shape. The parietal wall bears a weak fold similar to that in C. bembix. The peristome is moderately expanded, being narrowest at the posterior corner and widest along the baso-columellar margin. The axis is smooth and about M-% the diameter of the shell. It is spindle-shaped within each whorl and bears a low, spiral swelling just above the floor of the whorls. 1971 THOMPSON: MEXICAN LAND SNAILS 277 Length of shell 14.4-20.2 mm (20.0); width 5.9-6.9 mm (6.4); aper- ture height 3.3-4.1 mm (4.0); aperture width 3.5-4.2 mm (4.2). Meas- urements in parenthesis pertain to holotype. TYPE LOCALITY,-A limestone ledge 16.4 mi. N of Zumpango del A B C DE FIGURE 4. ('m lost<'11 inia eclip< A new species. A. Holotype. B-E. Paratypes 278 BULLETIN FLORIDA STATE MUSEUM Vol. XV Rio, Guerrero; 2300 ft. elev. Snails were found on the ledge along clay seams aestivating beneath the fronds of a small fern. HOLOTYPE: UF 21210, cdllected 12 June, 1966 by Fred G. Thompson. PARATYPES: UF 21211 (55); instituto Politecnico Nacional, Mexico (5); same data as the holotype. REMARKS.-C. cclipes is a member of a small group that also in- cludes C. bembix and C . hazelae . These species have in common a mod - erately-large, opaque-white shell and a smooth axis. C. lissocentrt,m Pilsbry from Nuevo Le6n is similar in these characteristics, but no close relationship to the other three species is apparent. Similarly C. fuse(1 ( Martens ) and C . anaclasta have smooth axes, but both species are more similar in other shell aspects to the other species within the genus than to the hazelae group. ETYMOLOGY.-The species name eclipes is taken from the Greek eklipes, meaning devoid of or wanting, and refers to the snails smooth axis, lacking ribs or other sculpture. Coelostemma bembix new species DIAGNosis.-A species characterized by its globose, pupiform shape with an abbreviated spire consisting of scalariform whorls. In addition the auriculate-shaped aperture is extended forward on a long and recurved neck. The parietal wall of the aperture bears a large, laterally-compressed tubercular fold. Other characteristics include a wide, smooth axis, an imperforate umbilicus and the presence of oblique ribs on the apical cone and the last one or two whorls, while the inter- mittent whorls are feebly striate. ~HELL (Fig. 5, A-F).-Medium-sized and stocky. The shape is high- ly variable, ranging from depressed pupiform to globillar. The apical whorls are conspicueusly suppressed, with the embryonic whorls pro- truding as a short spike. The lower whorls decrease in size and the aperture is born on a long recurved neck. Whorls 13.0«15.0 (14.2 in holotype). Embryonic whorls 2.0-3.0 (2.8 in holotype). The first two embryonic whorls are minutely granular (Fig. 1, E). The last half of the second embryonic whorl bears increasingly disfinet vertical ribs that are about one-third the width of their intervals. The following 4-6 apical whorls are strongly ribbed with widely-spaced, slightly oblique axial ribs. The first·four post-embryonic whorls are strongly arched on the summit. The next 2-3 whorls, which form the widest part of the cone, are progressively flattened and scalariform. Below the periphery of the cone the shell usually is truncate and has 3-5 smooth, weakly- 1971 THOMPSON: MEXICAN LAND SNAILS 279 arched whoils in the middle. The lowest two whorls are crossed by strong widely-spaced axial ribs that beconic irregular and 111-defined (m the neck ofthe last whorl. The last whorl be:irs about 21-30 ribs (22 in hole,type). The aperture extends forward on a long recurved neck that is rounded except for a weak angle at the parietal-columellar margin. The umbilicus is imperforate. The aperture is irregularly ovate or pyri- . A B C /4. DE F FIGURE 5. Coe/ost,·mma hembix new species, A. Holotype. B-F. Pturatypes. 280 BULLETIN FLORIDA STATE MUSEUM Vol. XV form and is usually higher than wide. Internally the parietal wall bears a large, medium, laterally-compressed tubercular fold. The peristome is narrowly reflected around the aperture with the base extended and tiumpet-shaped. The axis is about one-third the diameter of the shell near the middle and taperS to a very narrow tube in the last three whorls. The axis is smooth, is slightly spindle-shaped within each whorl, and bears a weak spiral swelling just below the middle., Length of shell 15.3-18.9 min (16.7), width 7.0-8.6 min (8.0); aper- ture height 3.4-4.4 mni (4.3), aperture width 3.6-4.6 mm (4.1). Meas- urements in patenthesis pertain to holotype. TypE LocALITY.-Guerreto, 12.6 mi. N of Zumpahgo del Rio, 2300 ft. elev. At this point the Federal Highway 95 crosses a tributary of 'the Rio Balsas. Snails were collected on a limestone ledge above an old road cut paralleling the east bank of the river. They were found be- neath the fronds of a small fern growing along crevises in the ]edge. HOLOTYPE: UF 20901, collected 13 June, 1966 by Fred G. Thomp- SOn. PARATYPES: UF 20900 (110); Dept. Zoologia, Instituto Politec- nico Nacional, Mexico (10),same data as.the type. REMARKS.-C. bembix is · similar in shape to C . adrid Bartseh among the known species, although its relationship to C. cidi ici is not close. The most noticeable peculiarities of C:. bembixincludethe scalari- form apical whorls, the refiexed neck of the last whorl and the tuber- cular fold in the aperture. Additional differences that distinguish C. /, embix from C. adria include the sculpture on the middle portion of the shell, the lack of sculpture on the axis, and the imperforate umbili- cus. C. adria has weak riblets on the middle whorls, a modification of the stronger sculpture below and above, its axis has feeble vertical threads, and the umbilieus is narrowly perforate. ETYMOLOGY.-The specific name is taken from the Greek bembix, a top, in reference to the appearance of this snail. Coelostemma anaclasta new species DIAGNOSIS.-A moderately small species characterized by its ela- vate shape with protruding embryonic whorls, its peristome located on a long, refiexed neck that is weakly concave along its basal side, its narrowly rimate or imperforate umbilieus, and. its smooth axis that is spindle-shaped within each whorl. The sculpture on the embryonic whorls is minutely granular. The following apical whorls bear heavy, oblique axial ribs that tend to be crenulate along their lower suture and are very much reduced in intensity or are obsolete on the lower whorls. 1971 THOMPSON: MEXICAN LAND SNAILS 281 SnELL (Fig. 6, A-F).-The shell is moderately small (about 12-15 mm 1()ng) and clavate in shape. The aperture extends forward on a long reflexed neck. The umbilicus is narrowly rimate or imperforate, The color is dull tan, and the shell is subtranslucent. The embryonic whorls protrude strongly to form a nipple-like apex. The next 6-7 whorls rapidly increase in size to form a conical apex that is convex in outline. The remaining 6-7 whorls gradually decrease in size. The last whorl ends in a long, refiexed neck about 1.4-2.2 mm long. The . A B C -- i .--b.:4,4 'r-'S < D E F FIGURE 6. (,2,<'h).stimma unachis·ta new species. A, D. Holotype. B-C. Paratypes E. 11.1 mi. S Colima, Colima. F. 7.2 mi. ESE Colima, Colima. 282 BULLETIN FLORIDA STATE MUSEUM Vol. XV base of the last whorl is flat and bluntly angular at the periphery. The nearly quadrangular neck has a broad, shallow impression on the base and a slightly-flattened dorsal surface. There are 15.1-16.7 whorls, in- cluding 2.5-3.1 embryonic whorls. The embryonic whorls (Fig. 1, D) protrude strongly, have a deeply impressed suture and are sculptured with very fine granules. The last quarter embryonic whorl bears fine, indistinct, oblique threads that phase into the axial ribs on the succeed- ing whorl. The apical whorls are nearly flat, tend to be scalariform near the periphery, and bear strong, oblique ribs that are weakly crenu- late along the lower suture. The post-apical whorls are nearly flat, but have a distinctly impressed suture and are sculptured'with barely distinguishable axial riblets that may be obsolete on some whorls. The last whorl bears about 30 oblique arched ribs that are strongest near the base of the neck and become sharp and irregular on the neck. The aperture is ovate, has,a conspicuously reflected peristome, and is about 0.2 mm broader than wide. The peristome is broadest along the basal margin and.narrowest along the posterior angle. Internally thethroat is subtriangular in cross-section, resulting from a weak invagination on the base ofthe nfck and a weaker impression on the dorsal surface. The axis is broadest in the apex and decreased in size through the last whorl, although there is no appreciable change in the caliber of the lower whorls. The axis is spindle-shaped within each whorl, is smooth 'and marked with irregular, opaque white streaks. Length of shell 13.0-15.5 mm (15.5), width of shell 4.7-5.1 mm (5.1), aperture height 2.3-2.8 mm (2.8), aperture width 2.5-2.8 mm (2.8). Measurements are based on the type series. Those in parenthesis pertain to the holotype. GEOGRAPHIC VARIATION-The type series is characterized by hav- ing a raised apex that is conspicuously concave in outline below the embryonic wh6rls, by having weakly distinguishable, if irregular, ribs on the lower whorls, and by having a relatively long neck on the last whorl (Fig. 6, D). Specimens of a series from 11.1 mi. S of Colima have a raised conical apex that is weakly convex below the embryonic whorls, the whorls below the.apex are sculptured only with incremental striations, and the neck tends to be shorter (Fig. 6, E). Shells from 7.2 mi. ESE of Colima are similar to the last series insculpture, but have an even shorter neck and have a suppressed spire (Fig. 6, F). TypE LocALITY.-Colima, 1.9 mi. NE of Tecolapa, 700 ft. elev. (Tecolapa is a small town located on the C61ima-Manzanillo Highway and is about 25 mi. SSW of Colima). Snails were found aestivating in cracks in a small limestone ledge at the head of a small ravine about 300 yards west of the highway. The vegetatation consisted of a dense 1971 THOMPSON: MEXICAN LAND SNAILS 283 xeric scrub forest. HoLoT¥pE: UF 20927, collected 1 June, 1966 by Fred G. Thompson. ~ARATYPES: UF 20928 (20); Dept. Zoologia, Instituto Politecnico Nacional, Mexico (4); same data as the holotype. OTHER LocALITIES.-COLIMA:- 11.1 mi. S. 6f Colima, 1400 ft, elev. (UF 20926); 7.2 mi. ESE of Colima, 1200 ft. elev. (UF 20925). REMARKS.-C. anaclasta is readily distinguished from all other species by its general external appearance and its smooth spindle- shaped axis. Ofthe other known species with a smooth axis it resembles C. jusca most closely. It differs from C. fi,sca by its claviform shape, its long, reflexed neck, and its costulate sculpture on the apical whorls. C. anaclasta is remarkably like C. bembix in its long, reflexed neck and its smooth axis, but the similarities between the two species are secondary and do not indicate phylogenetic relationships. These char- acters also occur in Metastonia roemeri (Pfeiffer), a species that is con- sidered only remotely related. ETYMOLOGY.-The specific epithet is taken from the Greek (1/1 (l- klasto.5, meaning bent back or reflected, and refers to the Rexed neck ofthe aperture in this species. Coelostemma fusca ( Martens) 11010*pirci fusect Martens , 1897 ; Biol , Cent . Amer .: 281 , pl . 16 , figs , 20 -24 ( not 19). (Type locality: Omilteme, Guerrero). Holospira (Haplocion) fusca Martens , Pilsbry , 1902 ; Man . Conch ., Ser . II , 15 : 95 -96, pl, 25, figs, 8-10, 12-14.- Bartsch, 1906; Proc. U. S. Nat. Mus., 31: 146. 1 laplocion fuse(t ( Martens ), Bartsch, 1943 ; Jour , Wash . Acad , Sci ., 33: 56 . /hile,pira (A/egaxis) f,·¥ca Martens, Pilsbry, 1946; Monogr. Acad. Nat. Sci. Phila., (3), II: 123. Coeloxte,nma Jux<{1 (Martens), Pilsbry, 1953 ; Proc . Acad. Nat. Sci . Phila., 105 : 156. The species is commonly distributed from 6500-8000 feet elevation in the mountains to the east and west of Chilpancingo, Guerrero. Within this area it is found in mesic oak and mixed oak-conifer forests, where it is found characteristically on limestone. It Undergoes considerable local variation in size. The variation is not correlated with elevation but is characteristic ofparticular colonies. Ali other aspects of the shell, including sculpture, show little variability between populations. Measurements of three population samples are given in Table 3. The series from 0.6 mi. ESE of Omilteme (UF 20916) is considered topotypic and encompasses most ofthe measurements given by Martens (1897: 281). Measurements that he gives for his largest specimens 284 BULLETIN FLORIDA STATE MUSEUM Vol. XV and his first figure (Pl . 16 , Fig , 19) represent a species of Holospir,a (s.s.) presently undescribed. TABLE 3 . MEASUREMENTS ( in min) OF THREE POPULATION SAMPLES OF C. fusca. Number Length Width Aper. H. Aper. W. Whorls 20911 (45) 11.8-16.3 3.6-4.2 2.0-2.4 1.9-2.3 15.7-20.0 20916 (40) 9.3-14.6 3.1-3.7 1.7-2.3 1.7-2.1 14.2-20.1 20913 (58) 10.4-12.4 3.0-3.7 1.8-2.0 1.8-2.0 13.7-18.5 The seulpturing of the first four whorls is illustrated (Fig. 1, C). The embryonic whorls bear dense minute granulations, which are re- placed on the following whorls by irregular, fine, oblique striations. TypE LocALITY.-Omilteme, Guerrero. LECTOTYPE by present designation: British Museum (Natural History) 1901.6.22.1051, col- lected by H. H. Smith. The British Museum has eight syntypes of this species. Four specimens of //olospira sp. are also included in the type series (Mrs. Angela Crane, pers. comm.). 07'HER L~cALITIEs.-GUERRERO:- 11.2 mi. E of Tixtla, 6500 ft. elev. (UF 20911); 9.8 mi. SW of Chilpancingo, 7100 ft. elev. (UF 20917); 11.4 mi. W of Chilpancingo, 8400 ft. elev. (UF 20912); 12.4 mi. SW of Chilpancingo, 8400 ft. elev. (UF 20918), 6.2 mi. ESE of Omilteme, 6800 ft. elev. (UF 20913); 5.5 mi. ESE of Omilteme, 7000 ft. elev. (UF 20914); 3.5 mi. ESE of Omilteme, 7200 ft elev. (UF 20915); 0.6 mi. ESE of Omilteme, 7900 ft. elev. (UF 20916). Coelostemma richardi new species DIAGNOSIS.-A small claviform species (about 11-15 mm long) with a moderately-wide umbilicus, strong, close costulate sculpture through- out the length of the shell, 3-4 upper whorls that are weakly scalariform and on which the ribs form nodular crenulations along the outer edge, and a hollow axis that is spindleform within each whorl and bears irre- gular, oblique thread-riblets. SHELL (Fig. 7, A-E).-The shell is small and claviform. The umbil- ical opening ismoderately large and elliptical iii shape. The color ofthe spire is grayish-white. The embryonic whorls are tan, as are the next three or four apical whorls, which have nearly white, crenulated ribs along the outer edge. Whorls 13.3-16.3 (15.2 in holotype). Embryonic whorls 2.3-3.1 (2.7 in holotype); protruding and nipple-shaped. The 1971 THOMPSON: \IEXICAN LAND SNAILS 285 first two embryonie whorls (Fig. 1, H) are sculptured with minute gran- ulations. The following one-half whorl or so is crossed by very fairit thread riblets that tend to grade into the costulate sculpture of the sue- ceeding postembi yonic whorl. The first 3-4 postembryonic whorls form a low dome-shaped apex. The 4th through the Sth postembryonic whorls are scalariform and form the widest part ofthe shell. The follow- ing whorls are flat-sided, while the aperture is extended forward from the body whorl on a moderately-long neck. The neck is nearly round, A B C DE FIGURE 7. Cocloste 1111 } ia richardi new species . A . Holotype B -E. Pat·atypes 286 BULLETIN FLORIDA STATE MUSEUM Vol. XV being weakly compressed on the dorsal surface. The postembryonic whorls are sculptured with strong, dose, slightly oblique and arched axial ribs, which on the apex form weak nodes or crenulations along the lower ends. There are 50664 ribs on the penultimate whorl (51 in hole- type). The ribs become sharp and irregular on the neck ofthe aperture, and hardly extend onto the base of the last whorl. The aperture is irreg- ularly ovate in hape, Internally it is pinched at the posterior corner. The peristome is moderately-reflected, being widest along the basal and columellar margins and narrowest around the posterior cornef. The axis is about one-third the diameter ofthe shell. It is widest in the apex and becomes greatly reduced in the whorl. Within each whorl it is spindle- shaped and bears irregular, slightly oblique thread-riblets. There are about 25 riblets per whorl near the center of the spire and they are spaced about 5/mm. Length of shell 11.2-15.0 mm (13.9), width 4.5-5.3 mm (5.0), aperture height 2.5-2.8 mm (2.7), aperture width 2.6-2.9 mm (2.8). Measurements in parenthesis pertain to holotype. TypE LocALITY.-Oaxaca, 1.3 mi. NE of Tonala, 5000 ft. elev. Snails were collected at the base of a limestone hillside among clusters of a small fern growing on the stone in slightly damp areas. HOLO- TYPE: UF 20905, collected 4 July 1966 by my son, Richard L. Thomp- son, after whom the species is named. PARATYPES: UF 20906 (50); Dept. Zoologia, Instituto Politecnico Nacional, Mexico (5); same data as the holotype. REMARKS.-This snail is unlike any other known species. Its com- pact claviform shape, sculpture, scalariform whorls, and open umbilicus serve to distinguish it from all others. It is similar in appearance to C. adria (Bartsch), but that species differs by having more crowded and less distinct sculpture on the shell, by having a narrowly perforate umbil- icus, by having juxtaposed whorls instead of being scalariform along the apex, and by lacking crenulations along the outer edge of the apical whorls (Bartsch, 1926: 2). Unfortunately C. adria is known only from two specimens recovered from river drift along the Rio Balsas at Balsas, Guerrero. C. richardi is also similar to C. notogastor. Differ- ences between the two are discussed under the latter species. Similarities between C. richardi and C. bembix in the scalariform apical whorls are overshadowed by the many other differences that characterize C, bembix, including the smooth columella. Similarities between C. richardi and C. teucostoma are discussed above. Coelostemma notogastor new species DIAGNOSIS.-A narrowly umbilicate, medium-sized species (about 1971 TH()MPSON: MEXICAN LAND SNAILS 287 12-16 min long) of cylindrical-pupoid shape. The spire is moderately extended with two protruding, telescoped embryonic whorls that are sculptured with fine granules. The remaining whorls are sculptured with closely-spaced, arched thread-riblets. The aperture extends for- ward on a short neck. The axis bears a slight submedian swelling and is sculptured with irregular, coarse, oblique riblets. SHELL (Fi*. 8, A-E).-The shell is medium-sized. The lower por- tion is nearly cylindrical, while the spire is moderately attenuate, weak- lili A B C DE FlcuRE 8. Coclost('mill