UNIVERSITY OF FLORIDA
Gainesville 1970- 1971
FLORIDA STATE MUSEUM
Volume 15 Number 5
SOME MEXICAN LAND SNAILS
OF THE GENERA COELOSTEMMA AND METASTOMA (UROCOPTIDAE)
Fred G. Thompson
UNIVERSITY OF FLORIDA
Numbers of the BULLETIN OF THE FLORIDA STATE MUSEUM are published 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. leucosioma n. sp., C. bcnbix n. sp., C. clipss n. sp., C. anaclasta n. sp., C. richardi n. sp., C. notogastor n. sp.,
C. astraxis n. sp., C. fornax n. sp. and C. fornax ix n. ssp. Two new subgenera are also proposed: Crycoryne n. subg. (type species: C. astraxis) and Styloptyx n. subg. (type species: C. fornax). C. antricola Bartsch is reduced to subspecific status as C. bourgeoisana antricola. C. aiplaxis Pilsbry, type species of the subgenus Aperiaxis, is synonymized with C. coahuilensis (Bartsch). Metastoma is elevated from a subgenus of Holospira to generic status and is closely related to Coclostemmla. Aspects of the embryonic sculpture are determined for C. clizabcthae (Pilsbry), C. b. bourgeoisana Bartsch, C. b. antricola Bartsch, C. iqualaensis (Bartsch), C. hazelae Pilsbry, C. fusca (Martens), C. coaiuilensis (Bartsch) and Metastonla roemaeri (Pfeiffer). These are features omitted in earlier descriptions of these species.
This is a preliminary report on some Mexican land snails of the genus Coelostem ma. 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 Coclostenmna from southern Mexico require a review of the status of Metasto ma.
Coclostemma belongs 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
'Fred G. Thompson is Assistant Curator in Malacology at the Florida State Museum. His research includes systematics, zoogeography, and ecology of land and freshwater mollusks.
Thompson, Fred G. 1971. Some Mexican Land Snails of the Genera Coclostemama and Metastoma (Urocoptidae). Bull. Florida State Mus., vol. 15, no. 5, pp. 267-302.
268 BULLETIN FLORIDA STATE MUSEUM Vol. XV
parts of Mexico are further explored. The genera and subgenera are difficult to define, because their distinctions are based upon shell characters, some of which may be polyphyletic in derivation. Coelostenuna is recognized by its enlarged hollow axis. This character occurs in two other genera, Metastona and Allocoryphe, and close relationships may exist between these groups.
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 fusca 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 Epirobia coahuilensis Bartsch so that aspects of its embryonic sculpture could be determined. Gonzalo Halffter, Instituto Politeenico 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 4 was conducted with a collecting permit issued through the office of Rodolfo Hernandez Corzo, Direccion General de La Fauna Silvestre, Mexico. To all of C these people I am grateful. Most of the material studied is deposited in the Florida State Museum collections, University of Florida (UF).
Genus Coclostemma Dall
Coclostenna 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 by original designation: Holospira clizabethac Pilsbry, 1889).
Megaxis Pilsbry, 1946; Land Moll. N. Amer., 11(1): 123. (Type species by original designation: Holospirafusca Martens, 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.
Coelostemnma consists of four subgenera. The typical and most widely distributed subgenus has minute granular sculpture on the first two embryonic whorls followed by fine vertical ribs on the last half embryonic whorl. The second subgenus, Apertaxis, has only fine granular sculpture on the embryonic whorls. The two remaining subgenera have smooth embryonic whorls. They are localized in the same general region in north central Mexico and probably have a common origin from a single Coclostemma ancestry.
Coclostenima is most closely related to Metastoma. The large hollow 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 condition is approached in some species of the Holospira subgenus Allocoryphe, but whether a close relationship exists between Coclostemmla and Allocoryphc is uncertain. The phylogenetic relationships within Holospira s. 1. and Coelostcm ma are poorly established, and only extensive field work in Mexico will clarify the relationships.
Subgenus Coelostemma Dall
The typical subgenus has about two embryonic whorls that are sculptured with minute granules, which on the last 4 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 (s. s.) is in southern Mexico, primarily in Guerrero, Oaxaca, and Morelos. It probably will be found extensively in Puebla and Michoacan with some species occurring 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 Coelostemma (s.s.). Two species, C. marrsi Drake, 1951 and C. reiteri Drake, 1951, are known only from broken shells denuded of embryonic whorls, and their subgeneric allocation cannot be determined by embryonic 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. freytagi Bartsch, 1950, also from Chihuahua, C. dalli Pilsbry, 1902 and C. saltillensis Pilsbry, 1953 from Coahuila and C. lissocentrum Pilsbry, 1953 from Nuevo Le6n are described as being typical for Coelostemma (s.s.). Details of the embryonic sculpture for the last three species need to be confirmed.
Coclostemma (s. s.) consists of five or more groups of species, four of which are readily defined while others are less clearly delimited because of limited material from southern Mexico. The typical group, consisting of C. elizabethae 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. hazelac and two new species, has a smooth axis but is similar in other respects to the typical section. A third group, consisting of C. bourgcoisana 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. elizabethae, 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 appearance to this group and probably are derived from it.
Coelostenmma clizabethae (Pilsbry)
Holo.spira clizabethae 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 (Codlostemma) clizabethac Pilsbry, Dall, 1895; Naut., 9: 50.- Dall,
1895; Proc. U. S. Nat. Mus., 19: 347.- Bartsch, 1906; Proc. U. S. Nat. Mus., 31:
Coclosteima clizabethae (Pilsbry), Bartsch, 1943; Jour. Wash. Acad. Sci., 33: 58. Holospira claviformiis von Martens, 1897; Biol. Cent. Amer.: 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 earlier descriptions by Pilsbry (1889, 1902). The embryonic whorls are low and are separated by a relatively weakly-impressed suture. The first two or so embryonic whorls are sculptured with fine granules. The following quarter whorl bears fine axial ribs that begin along the upper suture, become increasingly intense, and grade into the coarser sculpture of the following post-embryonic whorl (Fig. 1, A).
SPECIMENS EXAMINED.--GUERRERO:- 11.2 mi. E of Tixtla, 6500 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).
Coelostemma iqualaensis (Bartsch)
Hlolo.hpira (Coelostemma) iqualaensis Bartsch, 1926; Proc. U. S. Nat. Mus., 70: 3-4; pl. 1, fig. 12. (Type locality: Iquala [Iguala], Guerrero). Coelostemma iqualaensis (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
FIGURE 1. Apical sculpture of Coclostemma. A. C. elizabethae (Pilsbry) (UF 20891). B. C. eclipses new species (holotype). C. C. fisca (Martens) (UF 20916). D. C. anaclasta new species (holotype). E. C. bembix new species (paratype). F. C. iqualaensis (Bartsch) (UF 20999). G. C. notogastor new species (paratype). H. C. richardi new species (paratype). I. C. Itcostona new species (holotype).
Coelostemma bourgeoisana bourgeoisana Bartsch
Coelostemma bouirgeoisana 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. iqualaensis and other species from southern Mexico.
272 BULLETIN FLORIDA STATE MUSEUM Vol. XV
TABLE 2. MEASUREMENTS (in mm) 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
antricola 21150 (50) 14.1-25.1 4.8-5.6 3.0-4.2 3.2-3.9 16.0-21.8
antricola 21149 (45) 17.0-24.9 4.8-5.5 2.9-3.8 3.0-3.7 17.2-21.4
antricola 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).
Coelostemma biourgeoisana antricola Bartsch
Coelostemma antricola Bartsch, 1943; Jour. Wash. Acad. Sci., 33: 58; fig. 5.
(Type locality: ravine near Las Grutas, Cacahuamilpa, Guerrero).
This subspecies previously was known only from two specimens collected at the type locality.
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. bourgeoisana because of the similar sculpturing on the axis in the two species. C. leucostoma differs from C. b. bourgcoisana and C. b. antricola by its slender shape, more attenuate apex, and less stronglyarched 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 aperture is white. The apex is attenuate, consisting of about 9-10 nearly flat-sided whorls. The following whorls are nearly uniform in diameter, decreasing slightly near the base. The aperture extends forward and laterally on a moderatelylong 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
I9M TII )omPSON: MEXICAN LANI) SNAll.S I7 3
A B C
D E F
FTrcURE 2. 0,t uhrt i( fc e moviaut flew spcies. A. Holotype. 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 embryonic whorls are sculptured with numerous fine granules, which are replaced on the last 4 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 uniformly 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 of the last whorl and extend around the base and into the umbilicus where they are finer and sharper. The aperture is nearly ovate in shape, being slightly flattened dorsally. The peristome is moderately expanded around the aperture, being widest along the base and narrowest dorsally. The.axis is about 3 the diameter J 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); aperture height 2.7-3.0 mm (3.0); aperture width 2.9-3.4 mm (3.2). Measurements in parenthesis pertain to the holotype.
TYPE LocALITY.-Ruinas de Xochicalco, Morelos; 4900 ft. elev. HOLOTYPE: UF 21145, collected 11 June, 1966 by Fred G. Thompson. PARATYPES: UF 21146 (113); Dept. Zoologia, Instituto Politecnico Nacional, Mexico (25); same data as the holotype. Snails were collected near the ruins from under limestone blocks over a caliche. The area contained submesic scrub and trees that were closely browsed by 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 flatter whorls. Aspects of the apical sculpture also suggest a relationship with C. richardi, described below. The two species are readily distinguished by their shapes and their axial sculpture.
ETYMOLOGY.-The specific epithet is derived from the Greek leukos, meaning white, and stoma meaning mouth and refers to the white aperture in this species.
Coclostemma hazelae Pilsbry
Coelostemma hazelae Pilsbry, 1953; Proc. Acad. Nat. Sci. Phila., 105-159; pl. 5,
fig. 4. (Type locality: between Chilpancingo and Mazatlan, 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 Mazatian, Guerrero, 4700 ft. alt. (UF 20997) differ by being considerably shorter stockier, though of similar width to the holotype (Fig. 3, D-F).
As in other species of Coelostenma from southern Mexico the emD E F
Fiame: 23, Co.lo.en.ma hozlur Pilsbrv. A-C. 2.2 mi. NE lzu, Gueirrero. D-F. 3.4 in. NNE Mazathin, Cuerrero.
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-riblets that grade into coarser riblets on the following postembryonic whorl.
Coelostemma eclipes new species
DIAcNosis.-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. Beacuse of its smooth axis it is related to C. hazelae and C. bembix, both of which occur in adjacent areas of Guerrero. C. clipss differs from C. hazelae 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. hazelac. C. eclipes is distinguished from C. bembix by the numerous peculiarities of the latter species described below.
SHELL (Fig. 4, A-E).-The shell is moderately large and stocky and is subcylindrical 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 holotype). 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 first two embryonic whorls are sculptured with dense, minute granulations. The subsequent 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 on 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-auriculate in 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 3- 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 IAHOMPSON: MEXICAN LAND SNAILS 177
Ieth1I of ihl II44-20.2 mnm (20.0); width 19-6.0 n mm (6 4); aperLure height 3:3-4.1 mm (4.0); ap rture width 3,5-4.2 mm (4.2). Masuirennts in parenthesis perltai to holotype.
TYi Loc.L.Y. -A Iimestone e. 1.6A mi. of Z/I.nping cll
A B C
Fu;il 4. C i1,,du n1 tcli t, m.w sp(.it A. H IoIovp. B-E. Iarat1es.
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, collected 12 June, 1966 by Fred G. Thompson. PARATYPES: UF 21211 (55); Instituto Politecnico Nacional, Mexico (5); same data as the holotype.
REMARKS.-C. eclipes is a member of a small group that also includes C. bembix and C. hazelae. These species have in common a moderately-large, opaque-white shell and a smooth axis. C. li.ssoccntrum Pilsbry from Nuevo Le6n is similar in these characteristics, but no close relationship to the other three species is apparent. Similarly C. fusca (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 intermittent whorls are feebly striate.
SHELL (Fig. 5, A-F).-Medium-sized and stocky. The shape is highly variable, ranging from depressed pupiform to globular. The apical whorls are conspicuously suppressed, with the embryonic whorls protruding 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 distinct 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[ 11I11PSON. \NI[C.A\ iLll) S\AillS
archd wih, os in be m icdlel. ITh lowest two 'I.hors are (.ross.l Ib strong widey-slUced axial ribs that bimi iregllar amid ill-dethiir d oni the ieck of ti last whorl. he last wlhr(i1 Iars b)u 21-30 ribs (22 i1
- liolotype). I 'lire extends foiwarf d on a ]ong recurved ieek that is
rouniidd (,pt Lor a weak ingle at the parietal-colurnellar margin.
T ulnilius I Im. perforite. Th apierture is irregularly ovate orpri
D E F
Finens, 5. .lo .r.n 1 Immln new species. A. Holotype. BIE baye
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 peristoine is narrowly reflected around the aperture with the base extended and trumpet-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 mm (16.7), width 7.0-8.6 mm (8.0); aperture height 3.4-4.4 mm (4.3), aperture width 3.6-4.6 mm (4.1). Measurements in parenthesis pertain to holotype.
TYPE LocALITY.-Guerrero, 12.6 mi. N of Zumpango 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 beneath the fronds of a small fern growing along crevises in the ledge. IIOLOTYPE: UF 20901, collected 13 June, 1966 by Fred G. Thompson. PARATYPES: UF 20900 (110); Dept. Zoologia, Instituto Politecnico Nacional, Mexico (10); same data as the type.
REMARKS.-C. bembix is similar in shape to C. adria Bartsch among the known species, although its relationship to C. adria is not close. The most noticeable peculiarities of C. bcmbix include the scalariform apical whorls, the reflexed neck of the last whorl and the tubercular fold in the aperture. Additional differences that distinguish C. bcnrbix from C. adria include the sculpture on the middle portion of the shell, the lack of sculpture on the axis, and the imperforate umbilicus. 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 umbilicus is narrowly perforate.
ETYoLoc.-The specific name is taken from the Greek bembix, a top, in reference to the appearance of this snail.
Coelostemma anaclasta new species
DmAcNosis.-A moderately small species characterized by its clavate shape with protruding embryonic whorls, its peristome located on a long, reflexed neck that is weakly concave along its basal side, its narrowly rimate or imperforate umbilicus, 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 TIOMPSON. MEXICAN LANI) SNAILS 281
SIIriI. (Fig. 6. A-P).-TheI sclI is noderatelN small (about 12-15
mm long) Idl clavate iT Shape. OIe aeIiTIr extends lbrvard oni a long refexed iick. Ihe Ilhnilieus is ]Iarrowly rmate or inerlate.
The cofor is dll taii, and th ShI is sIbtranlucIt. II embryoTic worls lpotrudT strongly to form a nipple-like apex. The Iext 6-7 whorls rapidly increase in sizI to form a conical apex that is Tomve in ant]lme. The remaining 6-7 whorls gradually decrease in size. The last whor I long. reflexed neck about 1.4-2. 2m long. The
-A B C
D E F
Fcut: 6. C 1o1Wn i n.ew species. A, 1.). IIoIotypc. 1-C. Paratypes
E. .L1 TiI. S Colima.(Xoima. F, 7.2 mi, ESE Colia. 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, including 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 succeeding whorl. The apical whorls are nearly flat, tend to be scalariform near the periphery, and bear strong, oblique ribs that are weakly crenulate 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 the throat is subtriangular in cross-section, resulting from a weak invagination on the base of the neck 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 having a raised apex that is conspicuously concave in outline below the embryonic whorls, 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 in sculpture, but have an even shorter neck and have a suppressed spire (Fig. 6, F).
TYPE LoCAUTY.-Colima, 1.9 mi. NE of Tecolapa, 700 ft. elev. (Tecolapa is a small town located on the Colima-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. HOLOTYPE: UF 20927, collected 1 June, 1966 by Fred G. Thompson. PARATYPES: UF 20928 (20); Dept. Zoologia, Instituto Politecnico Nacional, Mexico (4); same data as the holotype.
OTHER LoCALITIEs.-COLIMA:- 11.1 mi. S of Colima, 1400 ft. elev. (UF 20926); 7.2 mi. ESE of Colima, 1200 ft. elev. (UF 20925).
REMARKS.-C. GInaclasta is readily distinguished from all other species by its general external appearance and its smooth spindleshaped axis. Of the other known species with a smooth axis it resembles C. fusca most closely. It differs from C. fuisca 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 characters also occur in Metastoma roemeri (Pfeiffer), a species that is considered only remotely related.
ETYMOLOGY.-The specific epithet is taken from the Greek anaklastos, meaning bent back or reflected, and refers to the flexed neck of the aperture in this species.
H1olospira fusca 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.
Ilaplocion fusca (Martens), Bartsch, 1943; Jour. Wash. Acad. Sci., 33: 56. Hlolospira (Megaxis) fusca Martens, Pilsbry, 1946; Monogr. Acad. Nat. Sci. Phila.,
(3), II: 123.
Coelostemma fusca (Martens), Pilsbry, 1953; Proc. Acad. Nat. Sci. Phila., 105:
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 of particular colonies. All 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 of the 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 (PI. 16, Fig. 19) represent a species of Hlolospira J (s.s.) presently undescribed.
TABLE 3. MEASUREMENTS (in mm) 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 sculpturing of the first four whorls is illustrated (Fig. 1, C). The embryonic whorls bear dense minute granulations, which are replaced 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, collected by H. H. Smith. The British Museum has eight syntypes of this species. Four specimens of Holospira sp. are also included in the type series (Mrs. Angela Crane, pers. comm.).
OTHER LOCALITIES.-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
DIAGNOSI.-A small claviform species (about 11-15 mm long) with a moderately-wide umbilicus, strong, close costulate sculpture throughout 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 irregular, oblique thread-riblets.
SHELL (Fig. 7, A-E).-The shell is small and claviform. The umbilical opening is moderately large and elliptical in shape. The color of the 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 THIO\1(PO: MVXICAN LAN) SNAILS 285
frs (wo ernblrvnoic whorls (Fig. I H) are sculptured with minutes granulations. The followig one-half whori] or so is crossed h very Mint thread riblets that tend to grade into the ,ostulate sculptuI of the sueceeding postembryoui whorl. The first 3-4 postmbryoiic whorls formr a low dorne-shaped apex. The 4th though the 8th postemryloonie whorls are scalariform and frmn the widest part of the shell. The following whorls are flat-sided, while the aperture is extended fo ward from the body whorl on a noderately-ong neck. The neck is nearly round,
A B C
Frcuin. 7. .oo .nn r. i ucha r n ecis. A. HoIotype. B-E. ParatyPes.
286 BULLETIN FLORIDA STATE MUSEUM Vol. XV
being weakly compressed on the dorsal surface. The postembryonic whorls are sculptured with strong, close, slightly oblique and arched axial ribs, which on the apex form weak nodes or crenulations along the lower ends. There are 50-64 ribs on the penultimate whorl (51 in holotype). The ribs become sharp and irregular on the neck of the aperture, and hardly extend onto the base of the last whorl. The aperture is irregularly 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 corner. The axis is about one-third the diameter of the shell. It is widest in the apex and becomes greatly reduced in the whorl. Within each whorl it is spindleshaped 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. HOLOTYPE: UF 20905, collected 4 July 1966 by my son, Richard L. Thompson, 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 compact 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 umbilicus, 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. Differences 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. leucostoma are discussed above.
Coelostemma notogastor new species
DIAGNOSI.-A narrowly umbilicate, medium-sized species (about
1971 TI0O1PSON: NIVXICAN ILANI) SNAL[ES 287
12-16 mm 1ug) of cyliiidlrical-pupoid Sluape. Th spim iS mod(ratel extended with two p;rotru(lilng, telseoped mr.l onic w. orls that ore scilptulredl with fine grnules. The remaining whorls are sculpturtd with loslN-spac.d, arhed thread-riblets. .he apertuire 'Xtends farwaid on a short neIck. The axis hr shit sub median swellini and is sculptured with irregular course ,obli(ue riblels.
SIaLL. (Fig. 8, A-E) --The shell is mdiuri-sized. Th lower portion is nearly clindrical. wh[Il the spire IS mod1ratel} at1ieniatt. weakA B C
FTmTnI: 8, ( ocotmr ooutrlnw sp~ecie A. H olotype( B-E. Far-tyvpes.
288 BULLETIN FLORIDA STATE MUSEUM Vol. XV
ly convex in outline, and bears 2.3-2.8 protruding embryonic whorls s
(2.5 in holotype) that appear to be telescoped. The umbilical perforation is narrow and elliptical. The shell wall is moderately thick, subtranslucent when fresh, and dull fleshy-gray in color. Whorls 14.7-18.3 (17.0 in holotype). The embryonic whorls are sculptured with minute granules (Fig. 1, G). The last quarter of the second embryonic whorl bears fine, irregular threads that grade into the riblets on the succeeding whorl. The post embryonic whorls are sculptured with fine, close thread-riblets that are coarsest on the spire and the last whorl and weakest on the cylinder of the shell. The riblets on the spire tend to form nodules at their bases. The apical whorls are weakly arched, while the remaining whorls are only slightly curved. The lower two or three whorls are slightly reduced in size, the last ending in a short neck. The base of the last whorl and the neck are rounded. The aperture is subovate in shape with a flattened parietal margin and a slight protruberance from the upper lip. The interior of the aperture is broadly auriculate in cross-section. The peristome is weakly reflected along the upper lip and broadly so along the basal-columellar corner, where it appears to be drawn downward. The axis is about a third the diameter of the shell and is nearly uniform in width, except in the last whorl where it is markedly constricted. It bears a hollow, submedian spiral bulge within each whorl. The axis is sculptured with irregular, oblique, broken axial riblets between the roof of the whorls and the swelling.
Length of shell 12.0-16.4 mm (13.9), width 3.7-4.3 mm (4.1), aperture height 2.3-2.7 mm (2.6), aperture width 2.3-2.7 mm (2.4). Measurements are based on the type series, those in parenthesis pertain to the holotype.
The shell shows slight variation among the five population samples examined. Some specimens of other populations are larger than the measurements given for the type series, but broad overlap occurs between all samples. Some individuals from other samples also are claviform, but such specimens are exceptional.
TYPE LocALUTY.-Oaxaca, a limestone hill 14.2 mi. SW of Sola de Vega, 6500 ft. elev. HOLOTYIPE: UF 20910, collected 13 September, 1967 by Fred G. Thompson. PARATYPES: UF 20909 (35); Dept. Zoologia, Instituto Politecnico Nacional, Mexico (5); same data as the holotype.
OTHER LOCALITIES.-OAXACA:- 15.2 mi. SW of Sola de Vega, 6400 ft. elev. (UF 20922. 26); 5.7 mi. SW of Sola de Vega, 6300 ft. elev. (UF 20923. 75); 0.7 mi. S of Tlapacoyan, 5000 ft. elev. (UF 20921. 17); 4.9 mi. SSW of Tlapacoyan, 6100 ft. elev. (UF 20924. 24).
1971 THOMPSON: MEXICAN LAND SNAILS 289
ECOLOGICAL NOTES.-Snails were moderately common at all localities. At the type locality they were found under limestone blocks in a submesic oak forest. At other localities they were found under limestone rubble and caliche in submesic vegetation consisting of either dwarf oaks or grasses. These habitats are not so xeric as those occupied by other species of the genus.
REMARK.-This is the southern most known member of the genus. It is closely related to C. richardi Thompson as is suggested by similarities in the embryonic whorls, size, sculpture, and the open umbilicus. It differs from the latter by its general shape, finer sculpture, more attenuate spire, non-scalariform apex, spiral swelling on the axis, and coarser sculpture on the axis. The two species differ also in the shape and internal contour of their apertures as is described for each. C. notogastor also bears a similarity to C. fusca (Martens) in general appearance. C. fusca is readily differentiated by its smooth spindle-shaped axis, more attenuate spire, smooth-striate whorls, broader umbilicus, and smaller aperture.
ETYMOLOGY.-The name notogastor from the Greek notos, meaning south, and agastor, a near kinsman, refers to the geographic disposition of the species in relation to the rest of the genus.
Crycoryne new subgenus
TYPE SPECIES: Coelostemma astraxis new species.
The subgenus is distinguished from all other Holospirinae by having smooth embryonic whorls and large, hollow, nodular spines on the large, hollow axis. The character of the embryonic whorls relates Crycoryne to Styloptyx and Apertaxis the only groups of this subfamily that lack embryonic sculpturing. The axis is unlike that of any other genus or subgenus within the Holospirinae.
ETYMOLOGY.-The name Crycoryne is derived from the Greek kryptos, meaning hidden, and koryne, meaning a mace or war club and alludes to the characteristic axis of the subgenus. The name is of the feminine gender. The subgenus is monotypic.
Coelostemma (Crycoryne) astraxis new species
DIAGNOSIs.-A large species of Coclostemma readily distinguished from all others by its series of large nodular spines on the axis. It is also characterized by the combination of characters consisting of its large
290 BULLETIN FLORIDA STATE MUSEUM Vol. XV
A B C
FIGURE 9. Apical sculpture of Coclostenama and MIetfatoina, A. C. (Crycoryne) astraxis new species holotypee). B. C. (Apertaxis) coahuiliisis (Bartsch) (holotype). C. Metastoma roeneri (Pfeiffer). D. C. (Styloptyx) fornax new species (holotype). E. C. foriax ix new subspecies holotypee).
size, its nearly smooth cylindrical whorls, its protruding embryonic whorls, and its quadratic aperture.
SHELL (Fig. 10, A-E).-Moderately large (about 20-26 mm long) and cylindric conical in shape. The umbilicus is narrowly perforate. The shell is highly variable in obesity. Most specimens are more slender than the holotype (Fig. 10, A) and some individuals tend to be clavate in shape through reduction in size of the last few whorls. The shell is opaque and faint pinkish-white in color. Mature shells contain 17.8-21.5 weakly-arched whorls (18.5 in holotype). There are 2.1-3.0 embryonic whorls (2.2 in holotype) that protrude and are larger in caliber and width than the succeeding neanic whorl. The embryonic whorls are round, are separated by a deep suture, and are smooth (Fig. 9, A). The following 10 whorls gradually increase in size to the width of the shell and are slightly scalariform. The remaining whorls are nearly uniform in diameter, with the last two whorls slightly decreasing in width. The postembryonic whorls on the conical portion of the spire are sculptured with oblique low riblets that become obsolete at about the 10th whorl. The earlier whorls have about three ribs per mm. The cylindric
97 O\IIPSON 11EX[CAN 10N1) SNAIlS il
It:RE 10. CodoIstefnuuacI astraxis iew specis. A. Holotvpe. B-It Pararypes.
292 BULLETIN FLORIDA STATE MUSEUM Vol. XV
portion of the shell is nearly smooth with irregular, fine, incremental striations. The last whorl or two have low, relatively widely-spaced ribs that become more distinct and crowded near the peristome. The aperture is extended forward so that the peristome is free from the preceding whorl. The neck of the last whorl is irregularly rounded on the base. The aperture is quadratic in shape and is about as wide as high. The parietal wall of the aperture forms a strong angle with the columellar wall. The corners of the peristome are weakly angular. The basal margin is rounded. The peristome is moderately reflected around the aperture. It is most widely expanded along the basal and columellar margins and is least expanded along the outer lip. The axis is broad and hollow, about one-third the diameter of the shell, and bears about 5-6 large, obliquely-compressed and bluntly-pointed nodes per whorl. The interior of the axis is indented under the corresponding nodes. The nodes are more numerous and sharper in the conical portion of the spire.
Length of shell 20.2-26.0 mm (22.8), width 6.7-8.0 mm (8.0), aperture height and width 4.1-4.9 mm (4.9). Measurements in parenthesis pertain to holotype.
GEOGRAPHIC VARIATION.-This species is known from two places, the type locality and a hill about 18 miles WSW of the type locality. Specimens from the second location are nearly inseparable from the type series. They have slightly fewer whorls (17.1-18.2), and they tend to be more pupiform. Considerable overlap occurs in both of these characters.
TYPE LOCAILITY.-Durango, 9.0 mi. SSW of Picardias, 4400 ft. elev. (Picardias is a small town about 30 miles south of Torreon, Coahuila, and lies just west of the Durango-Coahuila state line). HOLOTYPE: UF 20903, collected 28 December 1969 by Fred G. Thompson. PARATYPES: UF 20902 (30); Direccion General de la Fauna Silvestre, Mexico (4); same data as the holotype.
OTHER LOCALITIES.-DURANGO:- 3.1 mi. SW of Pedricefia, 5000 ft. elev. (UF 20904).
REMARKS.-This species is unique within Coelostemma because of the nodose ornamentation on the axis. This feature differs so much from other types of axial sculpture in the genus that subgeneric rank is accorded this species.
In superficial aspect this snail is similar to the species described below from adjacent areas to the northwest. It differs in external characters most consistenly by its weakly-arched whorls, by its protrud-
1971 THOMPSON: MEXICAN LAND SNAILS 293
ing embryonic whorls, and by its quadratic aperture as well as by its profound axial differences.
ETYMOLOGY.-The specific epithet astraxis is derived from the Greek astron, a star, and axon, an axis, and alludes to the appearance of the axis in cross-section of the shell.
Styloptyx new subgenus
TYPE SPECIES: Coelostemmafornax new species
A subgenus of Coelostemma consisting of species that bear two spiral lamellae upon the axis of the shell. One lamella is large and occupies about the lower five whorls, where it lies upon the center of the axis. The second lamella is very much reduced in size, is confined to the last whorl, and lies between the first lamella and the floor ofthe whorl. The subgenus is also peculiar in having two large, smooth embryonic whorls, the second of which is partially and obliquely submerged beneath the adjacent whorls.
The subgenus is known to include one species containing two subspecies. The species has been collected from a small area in eastern Durango near Torre6n, Coahuila and extends over a NNE-SSW distance of at least 50 miles.
ETYMOLOGY.-From the Greek stylos, a column, and ptyx, a compressed fold. The name Styloptyx is of the feminine gender.
Coelostemma (Styloptyxifornax new species
DIAGNOSIS.-The distinguishing characteristics are the same as those of the subgenus, which includes the two spiral lamellae on the axis and the oblique embryonic whorls. The typical subspecies is distinguished by having distinct oblique ribs on all of the postembryonic whorls and by having nearly flattened whorls.
SHELL (Fig. 11, A-E).-Moderately large (about 17-23 mm long) and moderately slender. The shell is cylindrical with an apical cone that gradually increases in diameter to the maximum width of the shell at about one-third or one-fourth of the distance from the apex. The lower whorls near the aperture are slightly reduced in diameter. The shell is opaque and light tan with oblique white ribs. The 16.1-20.2 whorls (19.3 in holotype) are slightly arched at their periphery and have a moderately-impressed suture. The base of the last whorl is irregularly rounded but tends to be impressed along the outer wall. The umbilicus is narrowly perforate. The 1.9-2.5 embryonic whorls (2.3 in holotype) lie at an oblique angle to the axis of the shell so that a portion
291 ;l )LlTIN I I] )lA STATE MUSEUM Vol. XV
A B C
F.,.: 11 .olofru forrx new species. A. IHootype. B-E Paratyps
1971 THOMPSON: MEXICAN LAND SNAILS 295
of the second embryonic whorl is suppressed below the adjacent volutions and appears reduced in size. The embryonic whorls are smooth (Fig. 9, D). The succeeding whorls are crossed with oblique, slightlyarched axial ribs that are of nearly uniform intensity and are about equally spaced through the length of the shell. The 15th whorl has 49-77 ribs (49 in holotype) that are spaced about 3 per mm. The ribs on the last whorls become stronger and closer near the aperture. The aperture usually is free from and advanced beyond the preceding whorl. It is irregularly ovate in shape and generally is as wide as, or wider than, high. The interior of the aperture is made subtriangular by the angle formed by the parietal wall and columellar wall. The peristome is moderately reflected around the aperture. It is most expanded along the columellar and basal lips and least so along the upper-outer lip. The axis is large and hollow and is almost one-half the diameter of the shell near the middle of the spire. The axis is widest in the conical apex and gradually tapers to the width of the narrow umbilical perforation in the last whorl. The axis bears two spiral lamellae. The upper lamella usually occupies the last five whorls, is located just below the middle within each whorl, and is usually higher than wide. The second lamella is confined to the last whorl where it lies midway between the first lamella and the floor of the whorl. Generally it is narrower and lower than the first lamella. Neither lamella is evident within the aperture. In addition to the lamella, the axis shows irregular, oblique white streaks that are incremental lines of growth.
Length of shell 17.5-23.0 mm (21.1), width 5.4-6.9 mm (6.3), aperture height 3.3-4.1 mm (3.8), aperture width 3.4-4.4 mm (4.0). Measurements in parenthesis pertain to the holotype.
GEOGRAPHIC VARIATION.-A series of 39 specimens was collected on a limestone hill on the opposite side of the valley from the type locality, a distance of about 5 miles NNE. Specimens of this series tend to be larger and are less conspicuously ribbed, but they show no characteristics by which they can be consistently separated from the type series.
TYPE LOCALITY.-A limestone mountainside 2.2 miles S of the Presa Francisco Zarca, Durango; 4100 ft. elev. (The Presa Francisco Zarca is a dam on the Rio Nazas about 25 mi. SSE of Le6n Guzman and about 12 mi. NE of Pedricefia, and is about 5 mi. N of the Torre6nDurango Highway). The type locality lies at the base of a long high mountain ridge where snails were collected from under boulders and cactus in a talus slope. The area is extremely hot and dry, with only sparse, low, thorny vegetation. HOLOTYPE: UF 20895, collected 26 December 1969 by Fred G. Thompson. PARATYPES: UF 20898
296 BULLETIN FLORIDA STATE MUSEUM Vol. XV
(25); Direccion General de la Fauna Silvestre, Mexico (8); same data as the holotype.
OTHER LOCALITIE.-DURANGO:- limestone hill 5.5 mi. S, 1.8 mi. E of the Presa Francisco Zarca, 4200 ft. elev. (UF 20897).
REMARKS.-This species belongs to a group characterized by spiral axial lamella and oblique embryonic whorls. Two forms are known to belong to the group, C. fornax and the subspecies described below. C. fornax differs from the latter by possessing distinct axial ribs throughout the length of the shell. It also tends to be shorter and stockier, although these last characters are not consistently distinctive.
ETYMOLOGY.-The specific epithet fornax, taken from the Greek deity Fornax, the goddess of ovens, alludes to this snail's sun-scorched habitat.
Coelostemmafornax ix new ecies
DIAGNOSIs.-A form presumed to be subspecifically related to C. Fornax because of the similarity of all parameters of the shell except sculpture and whorl contour. Its sculpture differs from that offornax by having weak incremental striations on the whorls of the cylindric portion of the spire in contrast to the distinctly ribbed whorl offornax. The contour of its whorls differs by being more noticeably arched.
SHELL (Fig. 12, A-E).-Moderately large (about 20-26 mm long). The shell is cylindrical or elongate pupiform in shape. It is opaque, dull, and pinkish-white. There are 17.1-21.0 whorls (19.6 in holotype). The conical apex consists of 1.8-2.5 embryonic whorls (2.1 in holotype) and about 5 postembryonic whorls. The embryonic whorls are smooth and oblique (Fig. 9, E). The following 4-5 whorls are crossed by numerous, fine, oblique riblets that become crowded and indistinct with increasing whorl size. The whorls in the cylindrical portion are arched, nearly smooth, and crossed by irregular, fine, oblique striations. The last two or three whorls are reduced in size. The last one or two whorls have low widely-spaced riblets that become strongest on the periphery of the last whorl near the neck of the aperture. The neck is rounded on the base. The umbilicus is narrowly perforate. The aperture extends forward on a short neck, is broadly ovate or irregularly triangular in shape and usually is wider than high. The parietal wall of the aperture forms an obtuse angle with the columellar wall. The peristome is free from the preceding whorl and is moderately reflected.
197 '1THIOMPSON: MEXICAN LAND SNAILS 297
Fu;vx 12. Co;o(tenna(frax i new subspcivs. A. Holatype. B-E. Partyps.
300 BULLETIN FLORIDA STATE MUSEUM Vol. XV
Heretofore Mctastomfa has been treated as a subgenus of Holospira, an allocation that also has been used for most other related genera. The large hollow axis of Aletastona is similar to that of Coclostcnma and indicates a close phylogenetic relationship. This character contrasts strongly with the thin, solid, lamellate axis of Holospira. The presence of a strong, compressed, angular fold within the aperture is unique to Metastona among the Holospirinae and is herein considered sufficient basis for generic separation. The genus is monotypic. The characteristics of the apical sculpture described below for M. roemeri are more similar to that of the typical subgenus of Coclostemmna than to Crycoryne or Styloptyx and indicate a phylogeny with the former subgenus.
Metastoma roeneri (Pfeiffer)
Cylindrella roeenri Pfeiffer, 1848; Monogr. Helicorum Viventium, 2: 382. (Type .
locality: around New Braunfels, Comal County, Texas).
Holospira ro('neri (Pfeiffer), W. G. Binney, 1878; Terr. Moll., 5: 177, fig. 85.Pilsbry, 1903; Man. Conch., II, 15: 97-98; pl. 25, figs. 1-7.- Pilsbry, 1905; Proc.
Acad. Nat. Sci. Phila.,: 220; pl. 26, figs. 10-18.- Bartsch, 1906; Proc. U. S. Nat.
Mus., 31: 148.- Pilsbry, 1946; Land Moll. N. Amer., 11(1): 114-115; fig. 55. Holospira roeneri var. minor Cockerel, 1898; Nautilus, II: 136.
This species is widely distributed through southwestern Texas and southern New Mexico (Pilsbry, 1946: 115). The first 23 embryonic whorls have minute granular sculpture (Fig. 9, C). The following 4 embryonic whorl has very weak vertical threads that become more intense near the first postembryonic whorl.
Specific and subspecific names referred to Coclostemma are listed below with
their current systematic allocations.
adana Bartsch, (Holospira), 1926; Proc. U. S. Nat. Mus., 70: 3; pl. 1, fig. 14. (Type
locality: streamdrift from the Rio Balsas, Balsas Station, Guerrero). = C. (C.)
adria Bartsch, (Holospira), 1926; Proc. U. S. Nat. Mus., 70; 2-3; pl. 1, fig. 1. (Type
locality: streamdrift from the Rio Balsas, Balsas Station, Guerrero). = C. (C.)
amplaxis Pilsbry, 1953; Proc. Acad. Nat. Sci. Phila., 105: 159-160; pl. 3, figs. 3-3b.
(Type locality: Sierra Guadaloupe, back of Hacienda Guadaloupe, 75008000 ft. alt.). = C. (Apertaxis) coahuilensis (Bartsch).
anaclasta new species. (Type locality: 1.9 mi. NE of Tecolapa, Colima; 700 ft.
anconai Bartsch, 1951; Jour. Wash. Acad. Sci., 41: 146; figs. 1, 3. (Type locality: Ixcaptiopan, Guerrero). = C. (C.) anconai Bartsch. May be a subspecies of C.
(C.) bourgeoisana Bartsch. *
antricola Bartsch, 1943; Jour. Wash. Acad. Sci., 33: 58; fig. 5. (Type locality: Las Grutas, Cacahuamilpa, Guerrero). = C. (C.) bourgeoisana antricola Bartsch.
1971 THOMPSON: MEXICAN LAND SNAILS 301
astraxis new species. (Type locality: 9.0 mi. SSW of Picardias, Durango; 4400 ft.
balesi Pilsbry, 1954; Nautilus, 65: 82; pl. 8, fig. 4. (Type locality: Km. 175, near
Chilpancingo, on road to Acapulco, Guerrero). = C. (C.) balesi Pilsbry.
balsascnsis Bartsch, (lolospira), 1926; Proc. U. S. Nat. Mus., 70: 1-2; pl. 1, fig.
16. (Type locality: streamdrift from the Rio Balsas, Balsas Station, Guerrero).
= C. (C.) balsasensis (Bartsch).
bemnbix new species. (Type locality: 12.6 mi. N of Zumpango del Rio, Guerrero;
2300 ft. alt.).
bourgcoisana Bartsch, 1942; Jour. Wash. Acad. Sci., 32: 187; fig. 1. (Type locality: Ixtapan de la Sal, Mexico). = C. (C.) bourgeoisana bourgeoisana Bartsch.
bryantwalkeri Pilsbry, 1917; Naut., 30: 124-125; pl. 4, fig. 6. (Type localit: Rio
Conchos, Chihuahua); Subgeneric status uncertain.
chilpancingensis Pilsbry, 1953; Proc. Acad. Nat. Sci. Phila., 105: 158; pl. 5,
figs. 2-3a. (Type locality: between Chilpancingo and Mazatlan, Guerrero). = C.
(C.) chilpancingcnsis Pilsbry.
claviformis Martens, (Ilolospira), 1897; Biologia Centrali Americana: 277; pl.
16, figs. 10-16. (Type locality: Amula, Guerrero). = C. (C) clizabethae (Pilsbry). coahilensis Bartsch, (Epirobia), 1906; Proc. U. S. Nat. Mus., 31: 121; pl. 4, fig.
3. (Type locality: Sierra Guadaloupe, Coahuila). = C. (Apertaxis) coahuilensis
dalli Pilsbry, (Hlolospira), 1903; Man. Conch., Ser. II, 15: 100-101; pl. 26, figs.
28-31. (Type locality: Sierra de Guadaloupe, Coahuila). = C. (C.) dalli (Pilsbry). eclipes new species. (Type locality: 16.4 mi. N of Zumpango del Rio, Guerrero;
2300 ft. alt.).
elizabethac Pilsbry, 1889; Proc. Acad. Nat. Sci. Phila.: 81; pl. 3, figs. 1-5. (Type
locality: Amula, Guerrero). = C. (C.) elizabethae (Pilsbry).
fornax new species. (Type locality: 2.2 mi. S of the Presa Francisco Zarca, Durango; 4100 ft. alt.).
freytagi Bartsch, 1950; Jour. Wash. Acad. Sci., 40: 265; fig. 1. (Type locality:
Chihuahuan desert, 29 mi. W of Jim~nez, Chihuahua). Subgeneric status uncertain.
fusca Martens, (Holospira), 1897; Biologia Centrali Americana: 281; pl. 16, figs.
20-24. (Type locality: Omilteme, Guerrero). = C. (C.)fusca (Martens).
greggi Drake, 1951; Revista de la Sociedad Malacologica, 8: 40-41; pl. 6, figs.
3-4. (Type locality: foothills of the Sierra de Almoloya, near Cuevo Diablo,
near Salaices, Chihuahua). = Holospira (Haplocion) greggi (Drake).
hazelae Pilsbry, 1953; Proc. Acad. Nat. Sci. Phila., 105: 159; pl. 5, fig. 4. (Type locality: between Chilpancingo and Mazatlan, Guerrero). = C. (C.) hazelae
herrerae Bartsch, (H1olospira), 1906; Proc. U. S. Nat. Mus., 31: 150, pl. 4, fig.
14. (Type locality: Silaca Yuapan [Silacayoapan], Oaxaca). = C. (C.) herrerac
iqualaensis Bartsch, (Holospira), 1926; Proc. U. S. Nat. Mus., 70: 3, pl. 1, fig. 12.
(Type locality: Iquala [Iguala], Guerrero). = C. (C.) iqualaensis (Bartsch).
imbricata Martens, (Cylindrclla), 1863; Monatsber. Berl. Akad. Wissensch.: 540.
(Type locality: Mexico). = C. (C.) imnbricata (Martens).
ix new subspecies. (Type locality: 1.0 mi. E of Dinamita, Durango; 4900 ft. alt.). leucostona new species. (Type locality: Ruinas de Xochicalco, Morelos; 4900 ft.
302 BULLETIN FLORIDA STATE MUSEUM Vol. XV
lichcnophora Bartsch, (Ilolospira), 1906; Proc. U. S. Nat. Mus., 31: 146-147; pl.
4, fig. 7. (Type locality: Encarnacion, Hidalgo). = C. (C.) liclinophora (Bartsch). lissocentrum Pilsbry, 1953; Proc. Acad. Nat. Sci. Phila., 105: 158-159; pl. 8, figs.
5-5b. (Type locality: Cerro Potosi, Nuevo Le6n; 10,000 ft. alt.). = C. (C) lissocentrum Pilsbry.
marrsi Drake, 1951; Revista de la Sociedad Malacologica, 8: 39-40; pl. 6, figs.
1-2. (Type locality: Cuevo Diablo, near Salaices, Chihuahua). Subgeneric
microstoma Pfeiffer, (Cylindrella), 1861; Proc. Zool. Soc. London: 27. (Type locality: unknown). Status uncertain; may be a species of Coelostemma (Coelostmnima).
notogastor new species. (Type locality: 14.2 mi. SW of Sola de Vega, Oaxaca;
6500 ft. alt.).
prcsidioensis Bartsch, 1943; Jour. Wash. Acad. Sci., 33: 58-59; fig. 2. (Type locality: Presidio, Veracruz). = C. (C) presidioensis Bartsch.
reitcri Drake, 1951; Revista de la Sociedad Malacologica, 8: 41-42; pl. 6, figs. 5,
6. (Type locality: Los Remedios, Distrito Jim6nez, Chihuahua). Subgeneric
richardi new species. (Type locality: 1.3 mi. NE of Tonahi, Oaxaca; 5000 ft. alt.). saltillensis Pilsbry, 1953; Proc. Acad. Nat. Sci. Phila., 105: 157-158; pl. 5, figs.
5-5c. (Type locality: mountains on the right of the highest pass on road from
Saltillo to Diamonte, Coahuila, 7900 ft. alt.). = C. (C.) saltillensis Pilsbry.
strebeliana Pilsbry, (Holospira), 1903; Man. Conch., 15: 101; pl. 26, figs. 24-28.
(Type locality: Sierra de Guadaloupe, Coahuila). = C. (C.) dalli (Pilsbry).
townsendi Bartsch, (Iolospira), 1906; Proc. U. S. Nat. Mus., 31; 145-146;
pl. 4, fig. 13. (Type locality: Cerro Chilicote, Chihuahua). Subgeneric status
Five species, bryantwalkeri, freytagi, marrsi, reiteri, and totensendi, comprise a natural assemblage that probably merits subgeneric recognition. This group will be discussed elsewhere.
1906. The Urocoptid Mollusks from the Mainland of America in the Collection of United States National Museum. Proc. U. S. Nat. Mus., 31:
109-160; pls. 3-5.
1926. New Urocoptid Land Shells from Mexico. Proc. U. S. Nat. Mus., 70:
1-13; pl. 1.
Martens, Eduard von.
1890-1901. Biologia Centrali Americana: Land and Freshwater Mollusca.
London. 706 pp, 44 pls.
Pilsbry, Henry A.
1889. New and Little-known American Molluscs. No. 1. Proc. Acad. Nat.
Sci. Phila.; 81.
1902-1902. Manual of Conchology, Ser. II, 15: 1-323; pls. 1-65. Philadelphia.
1946. Land Mollusca of North America, 2(1): i-vi, 1-520. Philadelphia.
1953. Inland Mollusca of Northern Mexico. II. Urocoptidae, Pupillidae,
Strobilopsidae, Valloniidae and Cionellidae. Proc. Acad. Nat. Sci.
Phila., 105: 133-167; pls. 3-9.
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