Front Cover
 Table of Contents
 Subgenus coelocentrum Fischer and...
 Subgenus Ptychodonta Bartsch1
 Subgenus crossostephanus Dall
 Back Cover

Group Title: Bulletin of the Florida Museum of Natural History
Title: Land snails of the genus Coelocentrum from northeastern Mexico
Full Citation
Permanent Link: http://ufdc.ufl.edu/UF00095790/00001
 Material Information
Title: Land snails of the genus Coelocentrum from northeastern Mexico
Series Title: Bulletin - Florida Museum of Natural History ; volume 36, number 5
Physical Description: p. 141-173 : ill., map ; 23 cm.
Language: English
Creator: Thompson, Fred G. ( Fred Gilbert ), 1934-
Correa, Alfonso
Florida Museum of Natural History
Publisher: University of Florida
Place of Publication: Gainesville, Fla.
Publication Date: 1994
Copyright Date: 1994
Subject: Snails -- Classification -- Mexico   ( lcsh )
Genre: bibliography   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
Spatial Coverage: Mexico
Bibliography: Includes bibliographical references (p. 164).
General Note: Cover title.
General Note: Abstract in English and Spanish.
General Note: "Publication date: February 17, 1994"--P. 2 of cover.
Statement of Responsibility: Fred G. Thompson and Alfonso Correa.
 Record Information
Bibliographic ID: UF00095790
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 29887325

Table of Contents
    Front Cover
        Page 139
        Page 140
        Page 141
    Table of Contents
        Page 142
        Page 143
    Subgenus coelocentrum Fischer and Crosse
        Page 144
        Page 145
        Page 146
    Subgenus Ptychodonta Bartsch1
        Page 147
        Page 148
        Page 149
        Page 150
        Page 151
        Page 152
    Subgenus crossostephanus Dall
        Page 153
        Page 154
        Page 155
        Page 156
        Page 157
        Page 158
        Page 159
        Page 160
        Page 161
        Page 162
        Page 163
        Page 164
        Page 165
        Page 166
        Page 167
        Page 168
        Page 169
        Page 170
        Page 171
        Page 172
        Page 173
        Page 174
    Back Cover
        Page 175
Full Text


of the



Fred G. Thompson and Alfonso Correa

Biological Sciences, Volume 36, Number 5, pp. 141-173



BIOLOGICAL SCIENCES, are published at irregular intervals. Volumes contain about 300
pages and are not necessarily completed in any one calendar year.


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This public document was promulgated at an annual cost of $1455.40
OR $1.212 per copy. It makes available to libraries, scholars, and all
interested persons the results of researches in the natural sciences,
emphasizing the circum-Caribbean region.

ISSN: 0071-6154


Publication date: February 17, 1994

Price: $1.30


Fred G. Thompson' and Alfonso Correa2


Eleven species of Coelocentrum (GASTROPODA, PULMONATA, Urocoptidae) are recorded from
northeastern Mexico. Species recognition is most compatible with the evolutionary species concept Three
subgenera occur in the area (Coelocentrum s. s., Ptychodonta and Crossostephanus). The latter two
subgenera are redefined; Coelocentrum (Crossostephanus) palmer Dall and Bartsch, 1908 is described; C.
hinkleyi Pilsbry, 1909 is transferred from Coelocentrum s. s. to Crossostephanus and is figured for the first
time. The following new species are described: Coelocentrum (s. s.) penion, new species; Coelocentrum
(Ptychodonta) telescopium, new species; Coelocentrum (Ptychodonta) brachyacron, new species;
Coelocentrum (Crossostephanus) affinis, new species, Coelocentrum (Crossostephanus) priosculpta,
new species; Coelocentrum (Crossostephanus) paucinoda, new species, and Coelocentrum
(Crossostephanus) torosum, new species.
Key Words.- Biodiversity, speciation, M6xico, Hidalgo, Quer6taro, San Luis Potosi, Tamaulipas,
landsnail, Gastropoda, Pulmonata, Urocoptidae, Coelocentrum.


En el noreste de M6xico se registran once species de Coelocentrum (GASTROPODA,
PULMONATA, Urocoptidae). El reconocimiento de estas species es mas compatible con el concept
evolutivo de species. En el area existen tres subg6neros (Coelocentrum s. s., Ptychodonta and
Crossostephanus), de los cuales los dos iltimos subg6neros son redefinidos: Coelocentrum
(Crossostephanus) palmeri Dall and Bartsch, 1908 es descrita; C. hinkleyi Pilsbry, 1909 es descrita y
dibujada por primer vez y tranferida de Coelocentrum s. s. a Crossostephanus. Las siguientes nuevas
species son descritas: Coelocentrum (s. s.) penion, especie nueva; Coelocentrum (Ptychodonta)
telescopium, especie nueva; Coelocentrum (Ptychodonta) brachyacron, especie nueva; Coelocentrum
(Crossostephanus) affinis, especie nueva; Coelocentrum (Crossostephanus) priosculpta, especie nueva;

I Florida Musem of Natural Histoy. University of Florida, P. O. Box 117800, GainesviBe FL 32611-7800, U.SA
2 Insituto Tecnol6gico de Ciudad Victoria, Cd. Victoria, Tamaulipas Mexico.

Thompson, F.G., and A. Correa. 1994. Land snails of the genus Coelocentrum from northeastern M6xico.
Bull. Florida Mus. Nat Hist., Biol. Sci. 36(5):141-173.

Coelocentrum (Crossostephanus) paucinoda, especie nueva, y Coelocentrum (Crossostephanus)
torosum, especie nueva.


Introduction ................................................................................................................................................ 142
Acknow ledgm ents ........................................................................ .......................................................... 143
M methods ................................................................. .... ..... .................................................................... 143

Subgenus Coelocentrum

iCIjner a a crosse ........................................

oe ocen rum pe on, new spec es......................................................................................................
Subgenus Ptychodonta Ba tschl ...............................................................................................................
Coelocentrum astrophorea (D all)....................................................................................................
Coelocentrum telescopium new species .............................................................................................
Coelocentrum brachyacron, new species................................... ...............................................
Coelocentrum endolophus Pils ry.................................................. ..............................................
Subgenus Crossostephanus D all...................................................... ..................................................
Coelocentrum hinkleyi Pilsbry..................................................... .................................................
Coelocentrum aff inis, new species................................................... .............................................
Coelocentrum priosculpta, new species ............................................................ ...........................
Coelocentrum paucinoda, new species.....................................................................
Coelocentrum torosum new species................................................. ............................................
Coelocentrum palm eri D a l and Bartsch............................................ ..........................................
Literature Cited ...................................................................................... .............................................


Recent field work in northeastern Mexico reveals a rich radiation of
urocoptoid land snails of the genus Coelocentrum. The area discussed in this study
includes portions of Tamaulipas, San Luis Potosi, Quer6taro and Hidalgo along the
eastern fringe of the Sierra Madre Oriental (Fig. 1). This area contains numerous
limestone mountain ranges with complex climatic patterns and vegetation zones
that provide a myriad of diverse and isolated habitats. These conditions are
favorable for speciation among organisms, such as Coelocentrum, that are obligate
inhabitants of calcareous terrains and have very limited vagility. Supraspecific
diversity is greater in this area of M6xico than what we have encountered
elsewhere throughout the range of the genus. The area represents the northern
extent of Coelocentrum s. s. and it contains two locally endemic subgenera,
Ptychodonta and Crossostephanus. Our results are an under-measure of the

species diversity in this area. Surely many additional species will be discovered
with further exploration.
Coelocentrum species generally occur in colonies that are isolated by seemingly
minor, but real, ecological or physiographic barriers. Such isolation has resulted in
the evolution of numerous forms that have differentiated to varying degrees,
depending on the extent to which they have been genetically independent from
their nearest ally. Both the biological species concept (BSC) and the phylogenetic
species concept (PSC) are difficult to apply to patterns of speciation such as occurs
in Coelocentrum (Frost and Hillis, 1990). Both are testable only when related
biparental forms occur in sympatry and reproductive isolation can be demonstrated.
In the absence of sympathy they yield subjective and indecisive classifications. The
only case we have encountered of sympatry in Coelocentrum involves species
belonging to different subgenera. These are a new species described below of the
subgenus Coelocentrum and C. (Crossostephanus) palmeri. We have collected
Coelocentrum from numerous other localities in Mexico, Guatemala and Belize,
and all of these involve monotypic allopatry.


We wish to thank Steven P. Christman and Charlotte M. Porter (both of the
Florida Museum of Natural History), who have assisted us in the field. The
following individuals loaned us specimens in their care: Riidiger Bieler (Field
Museum of Natural History); Robert Hershler (U. S. National Museum of Natural
History). The distribution map of Coelocentrum in northeastern Mexico (Fig. 1)
was prepared by Anne V. Stokes. Photographs, including scanning electron micro
graphs (SEM's) were prepared by Elizabeth L. H. Raiser. Judy L. Donley and
Mary Lou Lyman assisted with the final preparation of the text. M. C. Juan R.
Trevino Higuera (Director, Consejo Tamaulipeco de Ciencia y Tecnologia
(COTACYT) and Ing. Tomas Garza Wong (Director, Instituto Technologico de
Cd. Victoria, Tamaulipas) provided economic support for the second author's
participation in this project. We are grateful to all of these persons for their


Taxonomic treatment of organisms that are allopatric and very restricted
ecologically, such as Coelocentrum, is most compatible with the evolutionary
species concept (ESC) as discussed by Frost and Hillis (1990). We have chosen to
recognize as species those forms that are (1) morphologically distinct, (2) that have
had an independent evolutionary history because of geographic and physiographic

isolation, and (3) that can be predicted to have an independent evolutionary
trajectory because of physiographic barriers that preclude reestablished genetic
contact with closely related taxa. The evolutionary species concept invokes some
degree of subjectivity regarding the recognition of species based on the above
criteria. The other concepts are more burdensome and yield interpretations that
are equally or more subjective.
Earlier descriptions of decollate land snails sometimes are difficult to interpret
because of ambiguity about what characterized the length and number of whorls in
the adult shell. Some descriptions include all of the remaining whorls above the
apical plug (Dall, 1908). The point at which the apical plug develops shows
relatively little variation within a given species and it is an important parameter of
the adult shell morphology. Most specimens also retain vestiges of the juvenile
shell above the plug. The vestiges may be small fragments of the previous whorl,
or they may be several complete whorls. Occasional adults retain the entire
embryonic and juvenile shell, even though an apical plug is formed at an
appropriate lower whorl. Unqualified measurements and counts of such shells
provide data that erroneously represents a given species.
Measurements used in this study were determined as follow. The number of
whorls includes only those from the upper end of apical plug to the aperture. The
length of the shell is measured from the top of the apical plug to the base of the
aperture. Portions of the juvenile shell that remained above the plug were removed
to take this measurement. The width of the shell is the width of the spire and
excludes the neck and aperture.
Data on embryonic and juvenile shell morphology are useful for showing
species relationships. The embryonic shell and subsequent juvenile shell are
conservative in size, rates of growth and sculpture. Species with similar embryonic
and juvenile shells may differ strikingly as adults (Crossostephanus). Conversely,
differences in juvenile shell characteristics may be highly significant for
distinguishing species (Ptychodonta).

Genus Coelocentrum Fischer and Crosse, 1872

Subgenus Coelocentrum s. s.

TYPE SPECIES: Cylindrella turris Pfeiffer, 1856.
The typical subgenus, Coelocentrum s. s., includes about twenty species. A
small group, which includes C. tanydeira Thompson, 1968 and the species
described below, is found in northeastern M6xico. Other species of Coelocentrum
s. s. inhabit Veracruz, Tabasco, Chiapas, Belize and Guatemala.
The correct subgeneric assignment of the two species from northeastern M6xico
is uncertain. Typical Coelocentrum (C. turris) has relatively large, inflated,
button-like embryonic whorls (Fig. 48), whereas C. tanydeira and the species

species described below have much narrower and relatively flattened whorls (Fig.
47). In both groups the embryonic sculpture consists of short segments of thread-
riblets along the shoulders of the whorls below the suture.

Coelocentrum penion, new species

DESCRIPTION (Figs. 2-6).- The shell is moderately small, about 20.0-
27.0 mm long and 6.3-7.7 mm wide. Moderately stocky, about 0.23-0.35 times as
wide as long. The shell is ovate-cylindrical in shape, and resembles a small spool
of twine in appearance. It is widest near the middle and tapers toward both ends.
The first whorl at the apical plug is 3.0-3.7 mm wide and is broadly perforate. The
umbilicus is imperforate. The aperture has a long slender descending neck that is
slightly longer than the diameter of the last whorl (Figs. 3, 5). The neck is
rounded but dorso-ventrally compressed. The aperture is obovate in shape and is
wider than long. It is small, being about 0.41-0.56 times the width of the shell.
The peristome is uniformly. narrow and reflected. The periostracum is light
yellow-brown in color and shiny. The peristome and the interior of the aperture
are white. Adult shells have 13.3-18.7 whorls below the apical plug. The whorls
are rounded at the periphery and are sculptured with narrow recurved axial ribs
that are about 1/5-1/7 the width of their intervals; 46-56 ribs on penultimate whorl,
49-63 on fifth and 45-58 on tenth whorl. The ribs on the neck are more crowded
and completely encircle the neck. The forward face of the ribs are slightly
concave. Their lower ends are expanded and knobby at the suture; their upper
ends are forked just below the upper suture producing a thinner, forward-directed
branch that partially coalesces with the next rib to produce a spiral subsutural
thread. The interspaces have occasional-numerous impressed spiral line-segments.
The axis is about 0.33-0.43 times the diameter of the shell and is concave in
outline between the septa (Fig. 5). The axis is sculptured with about 15 oblique
riblets that are separated from the bottom septum to form a narrow spiral channel.
The riblets bear several small pointed knobs which may combine to form short
combs. Measurements of adult shells are given in Table 1. The juvenile shell
remains unknown.

TYPE LOCALITY.-- Sierra de Cucharas, 7 km by road west of G6mez
Farias, TAMAULIPAS (23003'20"N, 9010'21"W); 730 m alt. HOLOTYPE: UF
190974; collected 25 June 1991 by Alfonso Correa. PARATYPES: UF 193540 (2);
same data as the holotype. PARATYPES: UF 193541 (4), ITCVZ 1005 (3); the
same general area at 430 m alt. (23001'24"N, 99009'42"W). The type locality is on
the east slope of the Sierra de Cucharas at the second bend of the road ascending to
San Jose,. The area was covered with a dense second-growth thicket of mountain
rain forest. Live snails were found in holes and pits perforating the limestone.
The locality at 430 m is not as wet as the type locality, but otherwise it is similar


TABLE 1.- Coelocentrum penion,, new species. Measurements in mm for the holotype and seven
paratypes. L = length; W = width; ApH = aperture height; ApW = aperture width; Wh = whorls; RP = ribs
on penultimate whorl; RS = ribs on fifth whorl; R10 = ribs on tenth whorl.

Specimen L W ApH ApW Wh RP R5 RIO

holotype 27.0 6.3 2.6 3.0 18.7 52 51 45
paratype 23.3 7.0 2.7 3.2 15.0 56 49 45
paratype 20.0 6.9 2.6 3.3 13.3 49 65 51
paratype 26.8 7.1 2.9 3.4 18.2 48 58 43
paratype 26.6 6.4 3.2 3.6 17.8 50 50 52
paratype 25.1 6.8 2.9 3.3 17.2 46 54 57
paratype 25.4 7.7 3.0 3.2 15.2 47 63 57
paratype 25.7 6.6 3.0 3.3 16.0 48

TABLE 2.- Coelocentrum tanydeira Thompson, 1968. Measurements in mm for the holotype (UF 19040)
and seven paratypes (UF 19042). Abbreviations as in Table 1.

Specimen L W ApH ApW Wh RP RS R1

holotype 27.3 6.1 3.4 3.5 16.0 64 58 54
paratype 29.8 6.4 3.3 3.6 16.4 54 62 61
paratype 28.4 6.0 3.4 3.6 16.3 53 60 68
paratype 27.4 6.0 3.2 16.2
paratype 27.3 6.2 3.2 15.3 54 57 67
paratype 26.8 6.0 3.2 3.6 15.1 55 64 50
paratype 26.0 5.0 3.4 3.5 15.7 57 60 61
paratype 25.5 6.0 3.2 3.5 15.3 54 70 50

DISTRIBUTION.- Known only from the area about the type locality.

REMARKS.-- Coelocentrum penion is most closely related to Coelocentrum
tanydeira Thompson, 1968, a species found near Xilitla, San Luis Potosi. Meristic
data for C. tanydeira are given in Table 2. The two snails are similar in size and
appearance. Both species have a long neck projecting forward from the last whorl,
and both have broken incised spiral line-segments in the interspaces between the
ribs. C tanydeira differs from C. penion by having a more slender, nearly
cylindrical shape, a relatively shorter and rounded neck (Fig. 7), a larger aperture,
its costate sculpture, and its columellar sculpture. In C. tanydeira, the aperture is
0.56-0.60 times the width of the shell; in C. penion, it is only 0.41-0.56 times the
width. In C. tanydeira, the ribs on the surface of the shell are closer, being about a
third of the width of their interspaces and are connected by a heavier subsutural
spiral cord that crosses over the upper ends of the ribs. The anterior face of the
ribs slopes forward in contrast to the concave face in C. pension. The riblets on the
columella of C. tanydeira are sculptured with minute granules along their edges,
unlike the pointed irregular knobs in C. penion. C. tanydeira differs also by
having an imperforate apical whorl in adult shells, in contrast to the broad
perforation in C. penion.

ETYMOLOGY.- The species name penion is derived from the Classical
Greek penion, a spool. It alludes to the resemblance of the shell to a small spool of

Subgenus Ptychodonta Bartsch, 1906

TYPE SPECIES: Coelocentrum astrophorea Dall, 1897.

The subgenus consists of a small group of species from northwestern Hidalgo
and eastern Quer6taro. It is characterized by having moderate-sized embryonic
whorls that bear numerous, close, complete thread-riblets (Fig. 46), and by having
a sharp, turgid, spiral ridge on the columella. The ridge bears a row of short radial
spines. The ridge is a hollow evagination of the columellar wall, and is not a solid
lamellar blade such as occurs in other genera (e. g. Oligostylus, Anisospira and

Coelocentrum astrophorea Dall, 1897

Coelocentrum astrophorea Dall, 1897. Nautilus, 11: 62.-- Bartsch, 1906; Proc. U.
S. National Museum, 31: 118; text figs. 5-6.-- Pilsbry, 1903; Manual of
Conchology, Ser. I, 15: 45.
Coelocentrum acanthophorea Martens, 1901. Biologia Centrali-Americana: 634.
(Amendment for astrophorea ?).

TYPE.- Holotype USNM 134696 (lost).

TYPE LOCALITY.-- Encarnacion, Hidalgo, Mexico.

DISTRIBUTION.-- Known only from the type locality.

REMARKS.-- Dall (1897) gives no indication about the number of specimens
that comprise the type series. Bartsch (1906) gives measurements for the type and
three paratypes. Recently, none of the type specimens could be located in the
USNM collection, and presumably they are lost.

Coelocentrum telescopium, new species

DESCRIPTION (Figs. 8-11, 46, 50).-- The shell is cylindrical with the upper
third tapered and the last whorl slightly narrowed. Robust, 0.21-0.28 times as wide
as high. Shell large, adults about 46.0-54.1 mm long, and 10.8-13.0 mm wide.
Apical whorl 4.1-4.5 mm wide and narrowly perforate. Umbilicus rimate.
Aperture on a short neck that projects forward for about a fourth of the diameter of
the last whorl (Fig. 9). Neck weakly constricted behind aperture, triangular-ovate
in cross-section; base obtusely rounded, without basal keel. Aperture broadly
triangular in shape, highly variable in relative height and width; generally about
0.55-0.60 times the width of the shell; plane of aperture moderately prosocline
(Fig. 9). Peristome blunt-edged and weakly reflected. Interior of aperture grayish-
white. Adult shells with about 17-20 whorls below apical plug. Suture moderately
impressed; whorls weakly arched and with a narrow sharp shoulder that is
accentuated by a weak, nearly obsolete spiral cord so that the whorls appear to be
telescoped. Ground color yellow-brown. Surface of whorls sculptured with
regularly spaced, low, retroactively arched, flat-topped whitish ribs that are about
half as wide as their interspaces; ribs tending to become narrower and more
crowded on lower whorls; 80-110 ribs on penultimate whorl, 67-98 on fifth whorl
and 63-79 on tenth whorl above aperture holotypee 87, 74, 60); ribs continue
around base into umbilicus. Interspaces between ribs with occasional segments of


TABLE 3.- Coelocentrum telescopium, new species. Measurements in mm for the holotype and seven
paratypes. Abbreviations as in Table 1 (page 146).

Specimen L W ApH ApW Wh RP R5 R10

holotype 51.4 12.2 7.0 7.3 20.3 87 84 79
paratype 54.1 11.8 7.6 7.1 20.3 87 77 76
paratype 52.8 11.1 7.3 6.5 19.8 108 86 74
paratype 49.9 11.8 7.9 6.6 18.2 88 73 67
paratype 49.7 10.9 6.0 7.0 19.0 89 74 60
paratype 47.6 10.8 6.7 6.5 19.8 110 98 77
paratype 46.0 13.0 7.2 5.5 17.5 79

low rounded spiral cords. Axis hollow and spindle-shaped; about two-thirds the
width of the shell near the middle and about a third of the width in the penultimate
whorl; surface smooth but with a strong spiral ridge just below the center; ridge
bearing flattened forward-directed short radial spines (Fig. 11); ridge present
throughout length of shell from first whorl below apical plug; spines begin on fifth
whorl below plug, and become reduced to irregular knobs in penultimate whorl;
about 20 spines present on ridge within antepenultimate whorl. Measurements for
seven adult shells are given in Table 3.
Juvenile shell attenuate (Fig. 50); rates of growth indicate that about 18
whorls are lost above apical plug. Embryonic shell cylindrical (two specimens
examined), containing 7 whorls about 1.45 mm in diameter; first 1.5 whorls
smooth; remaining embryonic whorls with fine, close axial riblets that grade into
the sculpture of the postembryonic shell (Fig. 46).

TYPE LOCALITY.-- QUERITARO, 7 km southwest of El Lobo; 2100 m
alt. El Lobo is located on the road from Xilitla to Querdtaro (Hwy. 120) and is
about 10 km southwest of Ahuacatlan, San Luis Potosi. Snails were collected from
along the microtower road that turns to the west about 5 km SW of El Lobo. The
area was forested with sparse oaks on a limestone hillside. Snails were found
under boulders and crawling in the open after a rain from the previous night.
HOLOTYPE: UF 34493; collected 25 September 1970 by Fred G. Thompson and
Russell Parks. PARATYPES: UF 193539 (6), Instituto Tecnol6gico Ciudad
Victoria ITCVZ 1003 (3); same data as the holotype. UF 34331 (3); paratopotypes.


REMARKS.- This species is compared to Coelocentrum astrophorea Dall,
1897, because of similar sculpture on the columella and the lack of a palatal
lamella. Eight adult specimens were examined. None shows a trace of a palatal
lamella on the interior of the shell. It differs from C. astrophorea by its much
larger size and larger number of whorls (Table 3). Bartsch (1906) states that C.
astrophorea is 26.8-29.8 mm long, 7.3-7.7 mm wide and has 13-15 whorls, and his
figure indicates that C. atrophorea has a more deeply impressed suture than does
C. telescopium. A more detailed comparison is not possible because the type
specimens of C. astrophorea are lost.
Another species closely related to C. telescopium occurs in the region of Tres
Lagunas. It differs primarily by being shorter, by having closer and more
numerous ribs, by having a strong palatal lamella within the middle of the shell
and by having a more abbreviate juvenile shell with only five embryonic whorls.
Overlap in size and ribbing occurs between the two taxa, but other characters are
sufficiently distinct as to warrant separate taxonomic status. This second species is
described below.

ETYMOLOGY.-- The name telescopium is from the Latin, and alludes to the
appearance of the shell at the suture.

Coelocentrum brachyacron, new species

DESCRIPTION (Figs. 12-15, 51).-- Medium-sized, about 35.1-41.4 mm long
9.6-11.5 mm wide; about 0.23-0.33 times as wide as high. Cylindrical and stocky
in shape with the upper third of shell tapered. Umbilicus rimate; apical whorl
narrowly perforate. Whorl at apical plug 3 mm wide. Last whorl with a short neck
that extends forward for about 2 mm; neck ovate-triangular in cross-section and
not noticeably constricted. Aperture broadly ovate-triangular in shape; about 0.52-
0.65 times the width of the shell; interior whitish. Peristome narrowly and nearly
uniformly reflected. Adult shell with 14.5-19.0 weakly arched whorls. Shoulder of
whorls narrow and bounded along the top of the ribs by a thin spiral cord. Whorls
sculptured with close thin riblets that are about half as wide as their interspaces;
riblets/whorl about equal throughout cylindrical portion of spire and becoming
more widely spaced higher up; 105-150 riblets on penultimate whorl, 103-134 on
fifth whorl and 59-99 on tenth whorl above aperture; riblets continuing around
base and into umbilicus. Base generally imperforate and without basal keel.
Columella about 0.38-0.44 times width of shell; slightly wider in middle of shell
than below, and tapered above; with a broad spiral ridge in its middle that bears
about 13-18 spines per whorl; spines reduced to knobs in the last whorl. Interior of
shell with a strong palatal lamella 1-2 whorls in length in the 5-7 whorls above
aperture (Fig. 15); at upper end lamella winds along basal septum and becomes



TABLE 4.- Coelocentrum brachyacron, new species. Measurements of the holotype and twelve paratypes.
Abbreviations as in Table 1 (page).

Specimen L W ApH ApW Wh RP RS RIO

holotype 39.9 10.6 6.2 6.3 17.9 136 137 83
paratype 41.4 9.6 6.1 6.2 17.8 123
paratype 40.7 10.3 6.7 6.5 16.3 132 134 75
paratype 38.0 11.0 6.3 6.4 15.0
paratype 37.5 10.7 5.6 5.3 14.6 122 123 85
paratype 37.3 10.0 5.9 6.0 16.2
paratype 36.8 9.7 6.1 6.0 14.8 150 110 80
paratype 36.7 10.1 5.8 6.0 15.3 146 86
paratype 35.1 10.8 6.0 5.8 15.2 117 74
paratype 34.4 11.5 6.1 6.0 14.5 105 103 59

located in the middle of the outer wall at its lower end. Measurements of adult
shells are given in Table 4.
Rates of growth of five juvenile shells indicate that 13.5-15.0 whorls are lost
above apical plug. Juvenile shell with a relatively short and rapidly expanding
spire (Fig. 51). Embryonic shell cylindrical, consisting of five whorls; first whorl
1.45 mm in diameter, smooth; following four whorls with fine, close, vertical
riblets that grade into sculpture of postembryonic shell.

TYPE LOCALITY.- QUERETARO, 1 km southeast of Tres Lagunas; 2600
m alt. Tres Lagunas is reached by a graded road 8 km NNW from Highway 120
and 4.5 km SW of the San Luis Potosi Quer6taro State line. Snails were found
under slabs of limestone in an open oak-juniper forest. HOLOTYPE: UF 159627;
collected 15 January 1990 by Fred G. Thompson and Steven P. Christman.
PARATYPES: UF 193542 (10 adults and 6 juvs.), ITCVZ 1004 (2 adults, 1 juv.);
same data as the holotype.

OTHER LOCALITIES.-- QUERETARO: 2 km SE of Tres Lagunas, 2600
m alt. (UF 159609. 6 adults and 6 juvs.).

REMARKS.-- This species and Coelocentrum telescopium are closely
related, and they are similar in general appearance. The shorter embryonic shell,

the abbreviate juvenile shell, the narrower columella and the palatal lamella readily
differentiate C. brachyacron from C. telescopium.
The palatal lamella develops after adult growth is completed. It is present in
ten adults from the type lot and absent in five. Those that lack the lamella also are
thin-shelled, indicating that they have not reached definitive development. All
adults from the locality 2 km SE of Tres Lagunas have a lamella. The late
ontogenetic development of the palatal lamella in Coelocentrum brachyacron is
similar to the development of this feature in Holospira which typically has four
lamellae in the last whorl; a columellar, parietal, basal and palatal.
Ontogenetically they develop in that order upon completion of shell growth. The
palatal lamella may be absent or weakly developed in sub-adult specimens of
Holospira that normally have four lamellae.

ETYMOLOGY.-- The name brachyacron is from the Classical Greek
brachys, short and akron, spire, referring to the abbreviate juvenile shell of this

Coelocentrum endolophus Pilsbry, 1953

Coelocentrum endolophus Pilsbry, 1953. Proceedings of the Academy of Natural
Sciences of Philadelphia, 105: 134-135; pl. 3, figs. 4-5b.

TYPE LOCALITY.- Unknown; stated to be "between Chilpancingo and a
small town nearby called Mazatlan, Guerrero". This is doubtful. HOLOTYPE:
ANSP 190964.
The description of Coelocentrum endolophus was based on two specimens
which reportedly came from near Mazatlan, Guerrero (Pilsbry, 1953: pl. 3, figs. 5-
5a), and a single specimen collected by Maxwell Smith at Km 251 on the highway
from Cd. Mdxico to Cd. Valles (Hwy. 85) (Pilsbry, 1953; pl. 3, figs. 4-4a). The
second locality is about 15 km SSW of Jacala, Hidalgo. It is near Encarnaci6n, the
type locality of C. astrophorea Dall, 1897 and is within the known range of other
Ptychodonta. The Guerrero locality is remote from there. The geographic
distribution of other Pychodonta adds doubt to the origin of the holotype of C.
endolophus. Other Pychodonta are known only from a relatively small area in
northwestern Hidalgo and adjacent Querdtaro, a geologically isolated region of
Cretaceous limestones, which is parted in the middle by the Rio Moctezuma.
Coelocentrum astrophorea and C. endolophus occur south of the Rio Moctezuma;
C. telescopium and C. brachyacron occur north of the river. Considering that all
other known species of Coelocentrum have very restricted distributions it is not
plausible that C. endolophus could be so widely distributed as to occur in Guerrero
and Hidalgo. The type locality given in Pilsbry (1953: 134) is considered by us to
be incorrect. Conversely, there is no apparent reason to doubt the reliability of the
record from Km. 251, Hidalgo.

Subgenus Crossostephanus Dall, 1908

TYPE SPECIES: Coelocentrum palmeri Dall and Bartsch, 1908.

This subgenus is characterized by the sculpture of the embryonic whorls and
by having a turgid evagination on the columella which bears various solid ornate
knobs and scallops. The embryonic whorls are moderate-sized and bear coarse
riblets below the suture. The riblets are discontinuous across the whorls, but are
weakly expressed along the base (Fig. 49). The evagination and its sculpture
become enlarged in the lower whorls. In the less specialized species the
evagination is low and bears a few coarse nodes. In the most elaborately evolved
species, such as C. palmeri, the evagination is greatly extended as a pendulant fold,
and the knobs consist of large forward-directed overlapping leafs or plates.
Intermediate stages occur in other species. Within a given sample there may be
considerable individual variation in the degree of sculpturing on the columella.
Some specimens are nearly devoid of any tuberculation. This is correlated with
incomplete definitive growth. These are individuals that have definitive
development of the outer shell, but have not yet completed development internally.
Crossostephanus is known only from southeastern Tamaulipas and
immediately adjacent San Luis Potosi. The species inhabit a variety of vegetational
zones on limestone strata, including submesic scrub, mesic oak and pine forests
and mountain rain forests. Species appear to be numerous. The area within the
known range of the subgenus is poorly explored for mollusks, and large areas of
seemingly suitable habitat to the west and north remain completely unexplored.

Coelocentrum hinkleyi Pilsbry, 1909

Coelocentrum hinkleyi Pilsbry, 1909. Nautilus, 22: 138-139.

This species has not been illustrated previously (Figs. 20, 21, 33, 42-43). The
sculpture on the columella relates it to the following three species. As with other
Crossostephanus some individuals are devoid of nodular sculpture on the
columella; others may be quite rugose. Measurements of ten shells selected to
show variation are given in Table 5.
TYPE LOCALITY.- SAN LUIS POTOSi: highest mountain on south side
of river at Mecos Falls. Holotype in the ANSP.
DISTRIBUTION.-- Recorded only from the type locality and San Dieguito,
San Luis Potosi, M6xico.


TABLE 5.- Coelocentrum hinkleyi Pilsby, 1909. Shell measurements of ten paratypes (UF 50153).
Abbreviations as in Table 1 (page 146).

Specimen L W ApH ApW Wh RP R5 R10

paratype 38.9 8.2 5.7 5.6 12.5 58 59 57
paratype 37.1 8.3 5.1 5.1 12.5 52 58 47
paratype 37.1 8.0 5.2 5.5 11.8 54 57 47
paratype 36.6 8.1 5.0 5.4 12.0 53 55 45
paratype 36.4 7.9 5.3 5.4 13.7 63 62 56
paratype 35.0 8.0 4.8 5.2 11.3 50 49 50
paratype 34.7 8.0 5.6 5.6 12.2 52 54 43
paratype 34.6 7.7 4.9 5.1 11.9 55 47 44
paratype 34.1 7.2 4.5 5.0 13.3 65 64 54
paratype 33.2 7.6 4.6 5.0 12.4 59 60 52

Coelocentrum affinis, new species

DESCRIPTION (Figs. 16-19, 40).-- Medium-sized, about 38-44 mm in
length and about 9.2-10.4 mm wide; 0.22-0.26 times as wide as long. Shell tapered
or cylindric-tapered in shape with the upper half tapering and the lower half nearly
cylindrical; the last whorl is only slightly narrower than the penultimate whorl.
Periostracum dull brown in color; the interior of the aperture tinged brown,
becoming nearly white around the peristome. The umbilicus and the apical whorl
are imperforate. Adult shells have 12.2-14.2 moderately arched whorls that are
narrowly shouldered below the suture. The last whorl has a short neck, the length
of which is about 1/6-1/4 the diameter of the last whorl (Figs. 17-18). The neck is
slightly compressed dorso-ventrally and has a rounded base lacking any trace of a
basal crest. The suture is moderately impressed and is accentuated by a thin, wavy
spiral thread bounding the shoulder of the whorl. The whorls are sculptured with
thin low riblets that are about 1/6-1/10 the width of their interspaces; 52-69 riblets
on penultimate whorl; 55-81 on fifth whorl; 47-59 on tenth. The interspaces have
irregularly spaced and coarser short segments of spiral threads. The aperture is
wider than high and is about 0.62-0.71 times the width of the shell. It is variable
in shape but usually is ovate or triangular-ovate in shape with a slightly concave
parietal wall. A distinct angle occurs at the posterior corer. The peristome is


TABLE 6.- Coelocentrum affinis, new species. Shell measurements of the holotype (UF 159634) and ten
paratypes (UF 193543). Abbreviations as in Table 1 (page).

Specimen L W ApH ApW Wh RP R5 RIO

holotype 40.6 9.6 6.5 6.7 12.0 52 56 47
paratype 43.7 10.1 7.1 6.8 12.3 71 62 54
paratype 43.0 9.8 5.7 6.5 14.7 64 70 47
paratype 42.5 9.6 6.2 6.4 14.2 65 62 51
paratype 42.1 9.2 6.4 6.4 13.7 69 62 52
paratype 41.5 9.4 5.9 6.4 13.6 69 66 53
paratype 41.5 9.2 6.4 6.5 13.3 69 81 59
paratype 41.4 9.5 6.7 6.5 13.3 80 77 59
paratype 39.7 10.4 7.2 6.8 12.2 64 45
paratype 38.0 9.5 6.5 5.9 12.6 62 74 54
paratype 37.6 9.2 6.5 6.6 12.2 56 55 49

slightly thickened and rounded and is nearly uniformly and narrowly expanded
around the aperture. The columella is relatively narrow, being about 0.18-0.28
times the width of the shell. It gradually increases in diameter down to the
penultimate whorl and then becoming narrower in the last whorl (Fig. 40). The
middle of the columella between septa has a slight spiral bulge that is sculptured in
the last 3-4 whorls with about 8-10 sparse, oblique white bars or elongate nodes.
Measurements for adult shells are given in Table 6. The juvenile shell remains

TYPE LOCALITY.- Sierra Tamalave, 7 km west-southwest of Adolfo
Lopez Mateos, Tamaulipas; 350 m altitude. HOLOTYPE: UF 159634; collected
17 January 1990 by Fred G. Thompson and Steven P. Christman. PARATYPES:
UF 193543 (16 complete shells plus 5 fragments)), ITCVZ 1006 (10 adult shells);
same data as the holotype.
The Sierra Tamalave is a low limestone range with a north-south axis. The
type locality is in a steep ravine on the east slope of the sierra along the highway
from El Lim6n to Tula. The ravine was forested with a dense xeric scrub thicket.
Snail shells were found in the leaf litter and under boulders.

DISTRIBUTION.-- Known from the Sierra Tamalave at the type locality,
and at 12 km WSW of Adolfo Lopez Mateos, 450 m alt. (UF 159664).



REMARKS.- This species is most similar in appearance to Coelocentrum
hinkleyi Pilsbry. The latter species occurs at about 30 km to the southwest in the
Sierra Grande. The Sierra Tamalave and the Sierra Grande are separated by a dry
alluvial basin. Coelocentrum affinis differs from C. hinkleyi primarily by its larger
size (see Table 5), and by having a less constricted last whorl. Other aspects of the
shell including external sculpture and the columella are alike.

ETYMOLOGY.- The species name affinis is from the Latin, meaning
related to, in allusion to its close affinity to the following species.

Coelocentrumpriosculpta, new species

DESCRIPTION (Figs. 22-27, 52).-- Adult shell small; about 21-29 mm long
and about 0.22-0.24 times as wide as long. Shell tapered, slightly convex in
outline. Color light brown becoming whitish behind the peristome; interior of
aperture tan. Apical whorl and umbilicus imperforate. Adult shell with 10.8-13.3
moderately arched whorls. Base of last whorl with a nearly obsolete spiral ridge
along outer edge. Aperture extended forward on a short rounded neck that lacks a
basal ridge (Fig. 23); length of neck about a fourth the width of the last whorl;
flattened above and strongly angular in front of suture. Aperture about 0.63-0.71
times the width of the shell; obovate in shape; angular at posterior corer and less
so at parietal-columellar corer. Peristome slightly thickened and narrowly
reflected; slightly wider along base and columellar margin; narrowest along
parietal margin and upper outer lip. Suture deep; whorls with a narrow but abrupt
nearly horizontal shoulder that is accentuated by a wavy spiral thread connecting
upper ends of ribs. Whorls sculptured with low, rounded, recurved riblets that are
1/3-1/5 the width of their interspaces; 47-62 riblets on penultimate whorl; 48-64 on
fifth whorl; 38-54 on tenth whorl. Bases of riblets expanded and flattened, tending
to be forked. Interspaces between riblets with numerous irregular rather course
segments of spiral striations. Columella rather slender, about 0.16-0.22 times the
width of the shell (Fig. 24, 27); uniformly tapered to the penultimate whorl;
columella with a low swelling in center of each whorl. The swelling may be nearly
smooth throughout the length of the columella (Fig. 24), or it may bear a few
scattered small nodes in the last two or three whorls (Fig. 27). Measurements of
adult shells are given in Table 7.
The rate of growth of juvenile shell indicates that about 21 whorls are lost
above the point of decollation. Embryonic whorls 5, button-like in appearance;
first slightly higher but narrower; next three nearly cylindrical, 1.4 mm wide; fifth
slightly constricted. Sculpture and form of embryonic and juvenile shell similar to
C. penion.


TABLE 7.- Coelocentrum priosculpta, new species. Shell measurements of the holotype (UF 159672) and
ten paratypes (UF 193538). Abbreviations as in Table 1 (page 146).

Specimen L W ApH ApW Wh RP R5 RIO

holotype 27.9 6.3 4.4 4.5 13.0 56 54 51
paratype 28.5 6.3 4.2 4.1 13.3 50 59 47
paratype 28.1 6.6 4.3 4.6 13.6 47 52 45
paratype 28.1 6.6 4.0 4.2 12.6 57 55 46
paratype 27.6 6.7 4.5 4.7 10.8 55 56
paratype 27.5 6.0 4.1 4.1 13.0 62 50 54
paratype 26.7 6.0 4.1 4.1 13.6 57 48 46
paratype 26.2 6.0 4.1 4.0 12.0 57 64 44
paratype 25.9 6.3 4.0 4.0 12.5 53 50 45
paratype 23.8 5.8 3.9 4.0 11.6 49 51 38
paratype 21.8 5.3 3.5 3.6 12.2 54 60 44

TYPE LOCALITY.-- TAMAULIPAS: Sierra Grande, 2 km west of Santa
Maria de Guadalupe, 21 km west of Ocampo; 1100 m alt. HOLOTYPE: UF
159672; collected 18 January 1990 by Fred G. Thompson. PARATYPES: UF
193538 (15), ITCVZ 1007 (9); same data as the holotype. The type locality is in a
submesic limestone ravine that was forested with slender tall oaks (Quercus sp.).
No understory was present. Snail shells were common in the leaf-litter. Live
specimens were found under large boulders.

DISTRIBUTION.-- This species is known from Tamaulipas and immediately
adjacent San Luis Potosi at an altitude of 1000-1100 m in submesic habitats.

OTHER LOCALITIES.- SAN LUIS POTOSI: hwy. from Naranjos to Cd. El
Maiz (22029'06" N, 99025'00"W), 1000 m alt. UF 193537).

REMARKS.-- Coelocentrum priosculpta is distinguished from other species
of Crossostephanus by its small size, its costulate sculpture with the lower ends of
the riblets flattened and expanded to form short inverted Y's and its simple, nearly
smooth columella with only a few small nodes in the lower whorls. It is most
similar to C. hinkleyi Pilsbry, 1909 in the latter two characters. C. hinkleyi is a


much larger and relatively more attenuate species, and has a relatively longer neck
on the last whorl.

ETYMOLOGY.-- The species name is from the Latin, prior meaning early,
and sculpta, a carving, in reference to the primordial stage of sculpture on the

Coelocentrumpaucinoda, new species

DESCRIPTION (Figs. 28-32).- Moderately large and stocky; about 33-40
mm long and 8.8-10.6 mm wide; about 0.25-0.28 times as wide as high. Spire
nearly cylindrical; last whorl narrower; upper half tapered. Color light brown and
nearly lusterless. Adult shell with 11.3-12.7 whorls. Apical whorl imperforate;
4.9-6.1 mm wide. Umbilicus very narrowly perforate or rimate. Base of last whorl
rounded; with a weak ridge along outer margin. Aperture extended forward on a
short rounded neck (Fig. 29). Aperture broadly ovate in shape; parietal wall
flattened and forming a weak angle internally with the outer lip. Width of aperture
0.57-0.66 times the width of the shell. Peristome narrowly and uniformly
reflected. Whorls moderately arched and shouldered below the suture; shoulder
accentuated by a thin wavy spiral thread connecting the upper ends of the axial
riblets. Sculpture consisting of narrow, recurved, rounded riblets that are about
1/5-1/7 the width of their interspaces; penultimate whorl with 55-75 riblets; fifth
whorl, 65-84; tenth whorl, 45-61. Located between the riblets are irregular, fine,
spiral thread-segments. In most specimens these are quite numerous, although
they may be reduced or absent on the lower whorls in some individuals. Columella
tapered, 0.28-0.33 times the width of the shell at penultimate whorl (Fig. 30).
Columella with a low turgid spiral ridge which in the penultimate and
antipenultimate whorls bears about 7-9 white nodes per whorl; nodes round or
slightly elongate; length of nodes about equal to or less than the width of the spiral
swelling. External sculpture and other adult shell features are similar to C.
torosum. The juvenile shell is unknown. Measurements and other meristic data
are given in Table 8.

TYPE LOCALITY.-- TAMAULIPAS: limestone escarpment 3 km east of
and ascending to the village of G6mez Farias (23001'21" N, 99008'00"W); 300 m
alt. HOLOTYPE: UF 193544; collected 31 August 1991 by Alfonso Correa.
PARATYPES: UF 193545 (3), UF 193547 (20), ITCVZ 1008 (10); same data as
the holotype.

DISTRIBUTION.-- This species is known for certain only from the type
locality. We have before us a dead shell (UF 193546) collected from along the Rio


Frio, a few kms NE of the type locality (2207'48"N, 99004'24"W). Its point of
origin is uncertain.

REMARKS.- This species differs from the following species by its larger
size, its cylindric-tapered shape, its narrowly perforate umbilicus, and its wider
columella with sparser, more nearly rounded nodose sculpture. Although the two
taxa are quite similar, they differ sufficiently to warrant specific recognition. This
is supported by their geographic and ecological isolation. The ranges of the two
are separated by the Rio Guayalejo Basin, and by a distance of about 60 km. Both
species occupy upland limestone habitats, whereas the lowlands of the Guayalejo
Basin consists of alluvial and metamorphic deposits that are uninhabitable to

ETYMOLOGY.- The name paucinoda is derived from the Latin paucus,
few, and nodus, a knot or swelling, in reference to the columellar sculpture.

TABLE 8.- Coelocentrum paucinoda, new species. Shell measurements of the holotype (UF 193544) and
ten paratypes (UF 193545). Abbreviations as in Table 1 (page 146).

Specimen L W ApH ApW Wh RP RS RIO

holotype 38.5 10.5 6.2 6.2 11.7 67 76 51
paratype 39.7 9.9 6.7 6.4 12.7 67 80 55
paratype 38.4 10.0 6.6 6.2 12.5 64 84 61
paratype 37.6 10.6 6.0 6.3 12.8 64 68 56
paratype 35.7 9.7 6.3 6.1 12.0 62 70 45
paratype 35.3 8.8 5.4 5.6 12.7 70 77 49
paratype 35.2 9.9 5.5 5.7 11.9 62 65 72
paratype 35.1 9.5 5.8 5.6 12.5 61 70 57
paratype 34.6 9.3 6.1 6.0 11.6 75 89 53
paratype 34.2 9.1 5.8 6.0 12.1 64 74 58
paratype 33.2 9.7 6.6 6.4 11.3 55 65 4


Coelocentrum torosum, new species

DESCRIPTION (Figs. 34-37, 41).- Adult shell medium sized, about 26.8-
32.7 mm long and 8.0-9.0 mm wide; about 0.26-0.31 times as wide as high. Club-
shaped; upper 1/3 1/2 of spire tapered; top whorl at apical plug 4.2-5.5 mm wide;
lower portion of spire nearly cylindrical. Umbilicus and apical whorl imperforate.
Last whorl with an obsolete angle along periphery and ending with a short neck
about 1 mm long behind the aperture (Fig. 35). Color brown with a whitish
peristome and aperture; umbilical wall gray. About 8.8-11.6 whorls below apical
plug; whorls weakly convex; with conspicuous shoulders that are margined and
accentuated by a light-colored spiral thread. Suture moderately impressed. Whorls
sculptured with fine, recurved riblets that are about 1/4 1/5 the width of their
interspaces; 61-86 riblets on penultimate whorl, 62-86 on fifth and 43-65 on tenth
whorl above aperture; riblets connected at their upper ends by a narrower, lighter-
colored, wavy, spiral thread. Aperture rounded with a weak posterior angle;
usually wider than high and relatively large; about 0.6-0.7 times the width of the
shell. Peristome slightly thickened and moderately reflected. Columella slender;
about a tenth the width of the whorl near the apex, becoming enlarged in the lower
third of shell so that the sculptured columella is about 0.23-0.28 the width of the
whorl; axis with a slight spiral swelling that becomes enlarged in the lower whorls;
swelling with 6-8 large, elongate, white knobs per whorl in lower part of shell;
knobs about twice as long as wide; knobs usually confined to penultimate whorl;
occasionally on previous two whorls (Figs. 40). Measurements of adult shells are
given in Table 9.
Embryonic shell consisting of six whorls. First whorl rounded but not
conspicuously enlarged (in contrast to C. penion). Next two whorls gradually
increase in width to about 1.5-1.6 mm; following three whorls narrower. First
embryonic whorl smooth; next five whorls smooth but with coarse denticles along
the shoulder that crenulate the suture. Postembryonic whorls forming an attenuate,
weakly concave spire; sculptured with fine regularly spaced riblets, which by about
the twentieth whorl become connected along the upper suture by a thin spiral
thread. Rate of growth of juvenile shell indicates that about 19-21 whorls are lost
above apical plug.

TYPE LOCALITY.-- Sierra de Tamaulipas, 7 km northwest of Piruli,
Tamaulipas, Mexico; 350 m alt. (23034'27"N, 98033'50"W). HOLOTYPE: UF
189695; collected 8 February 1991 by Alfonso Correa and Fred G. Thompson.
PARATYPES: UF 193525 (75 adult shells and numerous fragments), ITCVZ 1009
(25); same data as the holotype. The type locality lies in a deep ravine near the top
of a limestone ridge. This locality is on the highway from Cd. Victoria to Soto La
Marina, and is about 54 km west of Soto La Marina. Snails were found under dead
leaves, logs and stones near the bottom of the ravine.


TABLE 9.- Coelocentrum torosum, new species. Shell measurements of the holotype (UF 189695) and
ten paratypes (UF 193525). Abbreviations as in Table 1 (page 146).

Specimen L W ApH ApW Wh RP RS RIO

holotype 32.1 9.0 6.2 6.3 10.2 68 71 55
paratype 32.7 8.9 5.5 5.9 11.3 61 66 52
paratype 32.7 8.4 5.2 5.6 12.3 73 86 64
paratype 32.3 8.7 6.1 6.1 11.6 76 76 54
paratype 30.2 8.0 5.1 5.2 11.2 64 64 49
paratype 28.7 8.1 5.3 5.5 10.2 86 75 65
paratype 28.6 8.0 4.9 5.3 11.6 67 62 43
paratype 28.0 8.1 4.9 5.6 10.1 79 76 45
paratype 27.5 8.0 5.1 5.3 10.3 66 63 48
paratype 27.4 8.6 5.2 5.1 10.4 74 75 50
paratype 26.8 8.3 5.5 5.5 8.8 77 77

DISTRIBUTION.- This species appears to be widely distributed within the
Sierra de Tamaulipas. It is known from 50-480 m altitude, and is common within
subcaducifolias forests.

OTHER SPECIMENS.- TAMAULIPAS. Sierra de Tamaulipas: Rancho El
Carrizo, Soto La Marina, 50 m alt. (UF 193526); El Moro, km 69, on road from
Cd. Victoria to Soto La Marina; 480 m alt., 23034'10"N, 98032'56"W (UF 193528,
UF193529); El Sabinito, km 97, on road from Cd. Victoria to Soto La Marina, 300
m alt. (UF 193527); 2 km W of El Sabinito, 27 km SW of Soto La Marina, 260 m
alt. (UF 189715).

REMARKS.-- Coelocentrum torosum is distinguished from other
Crossostephanus by its relatively small club-shaped shell, its relatively slender
columella bearing only a few elongate knobs or scallops in the lower 2-3 whorls,
and its imperforate umbilicus and apical whorl. As with other Coelocentrum some
populations differ significantly in shell features. Specimens from 2 km west of El
Sabinito attain a length of 30.4-35.8 mm, and the columella has scalloped nodes
within the lower four whorls. Other population samples we have examined are
very similar to the type series.

ETYMOLOGY.-- The species name torosum is from the Latin torosus,
meaning bulging, and refers to the knobby protuberances on the axis.

Coelocentrum palmeri Dall and Bartsch, 1908

Coelocentrum palmeri Dall and Bartsch, 1908. in Dall, 1908. Proceedings of the
United States National Museum, 35: 177-178; pl. 29, figs. 2, 5.- Solem, 1954;
Nautilus, 68: 7.

The original description was based on only a few specimens. Additional
material collected during recent years adds significantly to our knowledge of the
species and provides a basis for its redescription.

DESCRIPTION (Figs. 38, 39, 44, 45, 49).- This species is characterized by
its large stocky size and the sculpture on the columella. Color brown. Club-
shaped and stocky, being about 0.25-0.32 times as wide as high. Shell about 42-63
mm long; normally about 12.2-14.7 mm wide; apical whorl about 5.0-6.9 mm
wide. Aperture with a short neck the length of which is about a fifth the diameter
of the last whorl (Fig. 39). Base rounded and without a basal keel. Umbilicus
imperforate or narrowly rimate; apical whorl narrowly rimate. Aperture ovate-
triangular in shape; about 0.53-0.66 times the width of the shell. Peristome
slightly thickened and narrowly expanded. Whorls 11.3-13.5; separated by a
moderately impressed suture that is accentuated by a conspicuous wavy, spiral
thread bounding a narrow shoulder on the whorls. First whorl 4.9-6.9 mm wide;
subsequent whorls gradually increasing in size to the lower quarter of the shell,
and then the remaining 2-3 whorls becoming narrower. Whorls sculptured with
low, narrow, protracted, concave riblets that are about 1/5 the width of their
interspaces; 62-85 riblets on penultimate whorl, 58-81 on fifth whorl and 39-52 on
tenth whorl above the aperture. Upper ends of riblets connected at the shoulder by
a wavy, spiral thread. Occasional specimens have sparse spiral striations between
the riblets (most conspicuous in weathered shells and hardly distinguishable in
fresh specimens). Axis (Figs. 44, 45) hollow, slightly less than half the width of
the shell; with a wide evaginated ridge that begins at about 2-3 whorls below apical
plug; ridge increasing in size and overhanging to become deeply concave along its
lower wall in the last 3-4 whorls; ridge sculptures initially with indistinct ripples
which in lower whorls gradually form into nodes and forward-directed overlapping
leaves. Adult shell measurements are given in Table 10.
The rate of growth of juvenile shells indicates that about 21-23 whorls are lost
above the axial plug of the adult shell. Embryonic shell consisting of about 5.0
whorls. First whorl smooth, large and bulbous; next whorl slightly wider but
lower, 1.6 mm wide; subsequent three whorls slightly shorter between


TABLE 10.- Coelocentrum palmer Dall and Bartsch, 1908. Shell measurements of fourteen specimens
from the Sierra de Cucharas, west of G6mez Farlas, Tamaulipas at 430 m alt (UF 193531), and of the
LECTOTYPE (USNM 198083) and a LECTOPARATYPE (FMNH 62392). Abbreviations as in Table 1
(page 146).

Specimen L W ApH ApW Wh RP R5 RIO

UF 193531 63.3 12.5 8.0 7.6 17.0 62 66 50
51.3 13.9 7.6 8.2 13.0 67 64 39
50.0 12.5 7.0 8.2 13.0 68 80 49
49.8 12.8 7.8 7.6 11.3 59 79 46
47.2 12.8 7.6 7.8 12.8 69 81 45
46.7 12.4 7.2 7.0 12.7 85 58 39
46.6 13.8 7.7 8.5 11.8 43
46.5 12.5 7.0 7.5 13.0 81 71 43
46.5 12.3 7.0 7.1 12.8 63 64 51
44.6 13.0 7.0 7.4 12.8 72 64 50
42.8 12.2 6.7 7.3 11.5 65 66 39
42.0 13.5 8.7 8.4 11.0 74 89 52
17.0 9.5 9.0
Lectotype 51.1 14.7 9.0 8.2 13.0 82 70 50
Paratype 47.4 13.4 7.1 7.8 11.8 77 68 45

sutures and narrower in diameter, following whorls gradually increase in size to
form a slightly concave spire. Second whorl with fine radial striations along upper
suture. Sculpture on third and fourth whorl consisting of low but coarse grow-
wrinkles along the upper suture. Subsequent juvenile whorls with fine, regularly
spaced riblets that grade into the adult sculpture.

TYPE LOCALITY.- Dall and Bartsch (in Dall, 1908) give Tamaulipas,
Mexico as the type locality. The original label accompanying the lectotype states
that it was collected at G6mez Farias, Tamaulipas by Edward Palmer; 14-15 April
1907. The type series consisted of five specimens, but no holotype was designated.
LECTOTYPE by present designation: USNM 198083. This is the specimen
figured by Dall and Bartsch (1908: pl. 29, fig. 2). Two LECTOPARATYPES are
in the Field Museum of Natural History (FMNH 62392). Other type specimens
cited by Dall and Bartsch could not be located.


DISTRIBUTION.- Known only from the Sierra de Cucharas, west of G6mez
Farias, Tamaulipas, from 350-730 m altitude. This is a small mountain range that
has an area of approximately 900 km sq. and lies due west of G6mez Farias and
north of Ocampo. The range rises to a rolling plateau at about 1800 m with
numerous isolated hills and peaks as high as 2200 m. The range is inhabited by
several species of Coelocentrum representing two subgenera, Coelocentrum s. s.
and Crossostephanus.

Farias, 350 m alt. (UF 189680, UF 193534); east slope of Sierra de Cucharas W of
G6mez Farias, 470 m alt. (23001'43"W, 99009'24"W) (UF 193531); 7 km by road
W of G6mez Farias, 730 m alt. (23003'20"N, 99010'21"W) (UF 190972); road from
G6mez Farias to Rancho El Cielo (Alta Cimas), 430 m alt. (UF 193535); G6mez

REMARKS.- This is the largest known species of Crossostephanus, and it
columella is the most ornately sculptured of the subgenus. The measurements
given in Table 10 encompass most of the variation we have seen in other samples.


Bartsch, P. 1906. The urocoptid mollusks from the mainland of America in the collection of the United
States National Museum. Proc. U. S. Natl. Mus. 31: 109-190; phs. 3-5.
Dall, Wm H. 1897. New land snails from Mexico and New Mexico. Nautilus, 11: 61-62.
Dall, W. H. 1908. Descriptions and figures of some land and freshwater shells from Mexico, believed to be
new. Proc. U. S. Natl. Mus. 35: 177-182; pis. 29-30.
Frost, D. R. and D. M. Hillis. 1990. Species in concept and practice: herpetological application.
Herpetologica, 46: 87-104.
Martens, E. von. 1890-1901. Biologia Centrali Americana: 1-706; pls. 1-44.
Pilsbry, H. A. 1903. Manual of Conchology, Ser. I, 15: 1-323; pls. 1-64.
Pilsbty, H. A. 1909. New mollusks collected by Mr. A. A. Hinkley in San Luis Potosi, M6xico. Nautilus,
22: 138-140.
Pilsbry, H. A. 1953. Inland MOLLUSCA of northern M6xico. II. Urocoptidae, Pupillidae, Strobilopsidae,
Valloniidae and Cionellidae. Proc. Acad. Nat. Sci. Philadelphia, 105: 133-167; pis. 3-10.
Solem, A. 1954. Notes on Mexican mollusks. I: Durango, Coahuila and Tamaulipas with description of
two new Humboldtiana. Nautilus, 68: 3-10.
Thompson, F. G. 1968. Some Mexican land snails of the family Urocoptidae. Bull. Florida State Mus.,
Biol. Sci. 12(3): 125-183.



FIgure 1.- The distributions of Coelocentrum s. s. Pychodonta and Crossostephanus in Northeaster


Figures 2-6.- Coelocentrum penion, new species. Figures 2-3.- Holotype, front and side (UF 190974).
Figures 4-5.- Paratypes, front and side (UF 193540). Figure 6.- Paratype, opened shell
showing axis (UF 193541).
Figure 7.- Coelocentrum tanydeira Thompson, 1968. Holotype, side view (UF 19040).


Figures 8-11.- Coelocentrum telescopium, new species. Figures 8-9.- Holotype, front and side views
(UF 34493). Figures 10-11.- Paratypes, (UF 193539).
Figures 12-15.- Coelocentrum brachyacron, new species. Figures 12-13 Holotype, front and side
views (UF 159627). Figures 14-15 Paratypes (UF 193542).


Figures 16-19.- Coelocentrum ajfinis, new species. nlgures 16-17.- rront ana side views or nolorype
(UF 159634). Figures 18-19.- Front view ofparatypes (UF 193543).
Figures 20-21.- Coelocentrum hinkleyi Pilsbry, 1909. Paratypes (UF 50153).


Figures 22-27.- Coelocentrum priosculptum, new species. Figures 22-23.- Front and side views of
holotype (UF 159672). Figures 24-27.- Paratypes (UF 193538).


Figures 28-32.- Coelocentrum paucinoda, new species. Figures 28-29.- Front and side view of
holotype (UF 193544). Figures 30-32.- Paratypes (UF 193545).
Figure 33.- Coelocentrum hinkleyi Pilsbry, paratype (UF 50153).



Figures 34-37.- Coelocentrum torosum, new species. Figures 34-35.- Front and side views ofholotype
(UF 189695). Figures 36-37.- Paratypes (UF 193525).
Figures 38-39.- Coelocentrum palmer Dall and Bartsch, 1908; (UF 193535).


Figure 40.- Coelocentrum afinis, new species. Opened shell showing columella (UF 193543).
Figure 41.- Coelocentrum torosum, new species. Paratype (UF 193525).
Figures 42-43.- Coelocentrum hinkleyi Pilsbry, 1909. Paratypes (UF 50153).
Figures 44-45.- Coelocentrum palmer Dall and Bartsch, 1908. Opened shells showing axis (193531).
Figure 46 (next page).- Coelocentrum telescopium, new species, X14.
Figure 47(next page).- Coelocentrum tanydeira Thompson, 1968 (UF 190410, X14.


Figure 48.- Coelocentrum turris (Pfeiffer, 1856) (UF 190726), X14.
Figure 49.- Coelocentrum palmer Dall and Bartsch, 1906. (UF 190972), X14.
Figure 50.- Coelocentrum telescopium, new species. Paratype, juvenile shell (UF 193539).
Figure 51.- Coelocentrum brachyacron, new species. Paratype, juvenile shell (UF 193542).
Figure 52.- Coelocentrum priosculpta, new species. Paratype juvenile shell (UF 193538).

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