xt7xks6j3805 https://exploreuk.uky.edu/dips/xt7xks6j3805/data/mets.xml Alabama Alabama Museum of Natural History 1948 Other titles include: Alabama Museum of Natural History museum paper, Geological Survey of Alabama, Museum of the Geological Survey of Alabama. Other creators include: United States. Work Projects Administration, Geological Survey of Alabama, Tennessee Valley Authority. Issues for 1, 3 carry no series numbering. No. 2 also as Education papers no. 1. UK holds archival copy for ASERL Collaborative Federal Depository Program libraries. Call number AS36 .A2. journals English University, Ala. : Alabama Museum of Natural History, 1910-1960 This digital resource may be freely searched and displayed in accordance with U. S. copyright laws. Alabama Works Progress Administration Publications Museum Paper, no. 28, 1948 - including "Land Snails of the Genus Stenotrema in the Alabama Region" by Allan F. Archer text Museum Paper, no. 28, 1948 - including "Land Snails of the Genus Stenotrema in the Alabama Region" by Allan F. Archer 1948 1948 2015 true xt7xks6j3805 section xt7xks6j3805 GEOLOGICAL SURVEY OF ALABAMA
WALTER B. JONES, STATE GEOLOGIST
MUSEUM PAPER 2B
LAND SNAILS OF THE GENUS STENOTREMA IN THE
ALABAMA REGION
J By
{ ALLAN F. ARCHER W
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GEOLOGICAL SURVEY OF ALABAMA
WALTER B. JONES, STATE SE0L0S1ST
MUSEUM PAPER 28
LAND SNAILS OF THE GENUS STENOTREMA IN THE
ALABAMA REGION
By
ALLAN F. ARCHER
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iq LETTER OF TRANSMITTAL
J University, Alabama
December 11, 1948
it lloi»·i·al>le James E. Folsom
Governor of Alabama
Montgomery, Alabama
i Sirt
L 5 have the honor to transmit herewith the manuscript of a
i·ep·»i on "Land Snails of the Genus Stenotrema in the Ala-
bam. Region? It is requested that this be printed as Museum
Papa w 28 of the Geological Survey of Alabama.
Respectfully,
· WALTER B. JONES,
State Geologist
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INTRODUCTION ......,. V ,.,.............,...,4,rA.,,...,.·.... V ..V,......... ,rr.A.· V VVVVVVVV V 7
I ZnqV»geog1·aphy and DiSf1‘ibutiOl1 VV.....V..... V VVVVVVVVVVVV VV VVVVVV V VVVVV VV V V 8
Li,_‘{r)1Qg5Y _____,_v,r____ V ___>_,______>>_______,___,_____4,,__ V _,,,,,,_,,,4,_ V .VrVVVVV_.V V VVVA.A... VVVVVVVVV V. V V. V 10
OV Ewnomic Value _V,,,O.....V,, V VVV.VV V ..............VV.V..VVV.VV.. VV ...V. VVVVVVVVV VVVVVVVV 14
li ,—\%V·no1·ma1ities VVVVV.......VV.VVVV.V...V.V..V...... V VVVV.V.VVV...V.VV V .VV. V V.V.V V VVVV V V VVVV V VVVV V VVVVVVVVVVVVVV M
i SYS'[`E*XQ\*[ATIC CATALOGUE VV.VVVVVVVVVVVVVVVVV..VVVVVVVVVVVVVVV .......V.VV.V 15
MV-i1ez1·a1 Discussion .VVV...VV.....VV.V.VV.VV VVVVVVVVVVVVV VVVV V VVVVVV V V 15
_ '!`=w Genus Steiiotrema VVVV V VVVVAVVVVVV V OVVVVVVV VV VVVVVVVVVVVVV VV VVVVVVVVV VV 16
I
V i~§¤¢jr to Stenotrema VVVVVVVVVVVVVV V VVVVVVVVVVVVVVVVVV V VVVVVVV V .V.V V VVVV V VVVV V VVVVVVVVVV 16
‘ Smgenus Stanotrenia VVVVV VVVVVVVVVVVVV V VVVVVVVV V VVVV V VVVVVVVV V VVVVVVVV V V VV V 17
i Section Caracollatiis VVVVV VVVVV V VVVVVVVVVVVVVVVV V VVVV V VVVVV V VVVV 19
A isction Stenostoma VVVVVV V VVVV V VVVVV V VVVVVVVVVV V VVVVVVVVVVVVVV 27
i Viéction Toxotrema VVVVVVVVVVVVVV V VVVV V VVVV V VVVVVVVV V VVVV V VVVVVVVV VVVV VV VV 38
V ~*~€Cti0n Cohutta V V VVVVVVVVVVV V VVVVVVVVV V VVVVVV V VVVV V VVVV V VVVV 49
Néciion Maxillifer VoV__VVoVV____ V VV VVVV VV VVVVVVVVV V 51
*7 Wlénus Euchomotrema VVVVVV V VVVVVVVVVV V VVVV VV V VVVVVVVVVVVV V VVVV V 52
i
Pmzigs VVVVVVVVVV V VVV_V _VVV V VVVV_VVVV VVVVV V VVVVV VV V VVVV 61
INDLX VVVV V VV VVVVV V V V VV VV V VV V T8 f
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. LAND SNAILS OF THE GENUS STENOTREMA IN THE
- i ALABAMA REGION
. By i
Allan F. Archer
F INTRODUCTION J
This paper is the result of extensive field and laboratory
_ work carried on by the author upon the land snails, Stenotrema, A
» (l’oly;:y1‘idae) since 1931. The greatest part of the material
i was gathered in Alabama, Georgia, Tennessee, North Carolina,
and Virginia, as well as in other states nearby, while an ex- {
i tensive collection was made also in Arkansas and southern
_ Missouri during two different years. Material of comparative
1 value was taken at odd times both in the central United States Y
_ and in the Middle Atlantic States. The results contained in the E
f present publication are obtained from a dissertation submitted
‘ by the author in 1936 in partial fulfillment of the requirements i
‘ for tlne degree of doctor of philosophy in the University of Michi- i
. gan. Ann Arbor, Michigan. Subsequent to the completion of the
dissertation extensive revision and additional field work was i
carrieil on, especially in 1938. ;
I
l wish to acknowledge my indebtedness to the members of ¥
my doctorate committee, Mr. Calvin Goodrich, Drs. L. R. Dice,
G. ll. LaRue, L. Kellum, and L. C. Stuart for aid J
in the prosecution of this work. A great deal of the results
would not have been possible without the very material aid and E l
unfaiiing interest shown by Dr. Walter B. Jones and the Ala- i
hams Museum of Natural History. Dr. H. A. Pilsbry of the i
Academy of Natural Sciences of Philadelphia generously made
a very large collection available for study, as did also Mr. William
J· Cl' Museums, Ann Arbor, Michigan, as well as many friends ‘
and acquaintances for all sorts of helps and kindnesses.
This paper is intended as a useful manual of Stenotrema and i
a revision of the genus. The reader is referred to two papers
lll lf&Yti€ular containing 3 int nf valuable material on these i
snails; B. Walker, "The Terrestrial Shell-Bearing Mollusca of i
Ahbamarw Ala. Mus. Nat, Hist,, Museum Paper N0. 8, (1928); i
1
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T 8 GEOLOGICAL SURVEY OF ALABAMA
45-57; H. A. Pilsbry, "The Land Moilusca of North Aniericaf be L.
Acad. Nat. Sci. Phila., Mon. N0. 3, (l940)Z 639-688. Pilslny Sm
has brought all bibliography, descriptions, citations of type V Alu]
I localities up to date, and his monograph is very useful, although I gal-.
{ not always readily available. He took the genus Stenotrema out _
j of the all-inclusive genus Polygyra, and defined it on thc basis ,
of shell characters and on the soft anatomy. He figured the ‘ bore
shells of the species of Stenotrema beautifully and from more ° soui
fi: angles than is possible in the present work. By agreement he- asf
tween Pilsbry and the author information, notes, and manuscript dew
were furnished by the latter, but much of the classification and 7 Chia
arrangement found in the paper just cited were the result of the
.i.- l decisions arrived at by the writer of that paper. 1 tillll
bait
.; In considering the differences between the presem paper
and previous publications such as Pilsbry’s it should be realized hw
that the information to be presented is the most complete now s Hm.
_ z available. It has been arrived at as result of a very clo§§`
of Stenotrema, the main emphasis will be laid upon the Alaluaiin
Region. In order to go beyond the limits of W'alker’s p;;;ie1·oii
Alabama land snails, the Alabama Region by definition will not Lei
i only include Alabama but also those areas of neighboring state
i that are geographically and ecologically indistinguishablv f1`¢l?YY
it. The only physical features not found in Alabama we ills
middle and upper montane forests of the Great Smoky llomr ‘
tainS that have been the subject of much research by i2i\‘€5il: ' (ml
Z g&1tO1‘s of Appalachian faunas. The Alabama Museum of Néitlllili
{ History has had its part in the exploration of the Smokic< fron
"S th€ time of H. H. Smith until the present day_ In fact \vc* \l`Olli‘i
Ki .
LAND SNAILS OF THE GENUS STENOTREMA 9
vita" lie un;1i>le fully to understand our own local picture without the 1
.lsbi·3: study of neighboring areas. The states to be included in the
Wilt . Alahania Region are Georgia, northern Florida, western North
ioiigh l Carolina, eastern and middle Tennessee, and much of Mississippi.
a out .
basis . Stenotrema occupies a huge area in North America from the
tl the ' boreal forests to northern Florida, much of the Gulf Coast,
innre ' southwestward into Texas. westward across Oklahoma and Kansas
it bg. as far as Colorado Springs, Colorado. The two great centers of the
script develo;~inent of species are the area embracing the Appala-
[1 ami I chian Mountains together with the Great Smoky mountains in
ilt of the Southeast and another center in the Ozark Mountains con-
1 taining an abundance of species closely like those of the Ala-
bama liegion.
llflllgl State and federal parks and preserves contain much of our
Mlm best wildlife areas, and the lists of localities given below are ,
i mll G szmiplcs of what occur in them. Actually practically all of our 1
3 wl; SUlltlli*&lStj€1`D species will be found somewhere in the lists, and ,
FQ th » (l€UlU1l>?ll`3.t€ the value of parks and forests as preserves for our l
llll lll ` fauna. All parks in Alabama from which Stenotrema has been
lllmlll taken are listed here.
s and ,
Cllllll Baiiklicacl National Forest, Lawrence and Walker Counties, Ala-
JQ lama.
issui 1
reiieia Sienotrema barbigerum stenotrema
actcté S. spinosum l
llontis Sano State Park, Madison County, Alabama. 5
li (l“` Fitenotrema deceptum S. spinosum l
l‘llll?l S. exodon stenotrema
llllllllf N. monodon aliciae
ver 011
lll 1101 lJ°S'-W1 State Park. DeKalb County, Alabama.
s ates ·
Logg; lll€ll0lF€mH barbigerum S. spinosum
fg the N. deceptum stenotrema
Mom, 1 S. exodon turbinella k
lwslll l (Mk llount `
&mu.L,{ ‘ - aln State Park, Shelby County, Alabama. ;
*ll"lll} Sl€I10tl‘ema barbigerum S. l1iI‘Sl1tUII1 l
wouliz deceptum {
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-·——~~ V —· » v 14 _; A .v.v;. li'; L¤$,,l:._"';¢ N ¤:.';t;_:,V,]; y. _.,._.r..il_. ._4 . _»--·- sw. . .- ,,. aw,. .. , . . ._,
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§ 10 GEOLOGICAL SURVEY OF ALABAMA it 4
. Cheaha State Park, Cleburne and Talladega Counties, Alzilmm fer
' _ l v
g Stenotrema barbigerum S. Stenotrema _
. S. brevipila V the
. Chewacla Creek State Park, Lee County, Alabama. T wh
‘ I occ
_, Stenotrema maxillatum S. monodon aliciae _ hal
Ul T lac
l. TVA Area, Grassy Cove and Sequatchie Valley, Cumberland and V M
C Bledsoe Counties, Tennessee. S WO
A Stenotrema deceptum S. hirsutum it ‘l*i
S. edgarianum S. stenotrema ffl
(U
Smoky Mountain National Park, east Tennessee and vwestene fg]
rl North Carolina. Oi
5 Stenotrema altispira S. pilula
_ S. altispira depilatum S. stenotrema · he
S. fraternum montanum S. stenotrema voluminosum ru
Ml Cherokee National Forest, Polk County, Tennessee. p
. · 1..
Stenotrema barbigerum S. stenotrema » S;
* S. cohuttense S. stenotrema voluminosum (QI
T S. magnifumosum
Nantahala National Forest, North Carolina. f
A _ff Stenotrema altispira S. magnifumosum
~ S. barbigerum S. pilula ‘
W . S. fasciatum S. stenotrema volunainosum al
l‘‘” S. fraternum montanum lll
lll
Ecology. Species of the genus Stenotrema not only iiiliabll El
the forests and woodlands but also the clearings and culture lo
_-{X situations created by man in settling the country. l·lowerax
__te Qld the genus is not found universally present in eoniferous for€5l* _
,;_,' on poor acid soils either in the Deep South 0;- in the eastefli N
_` section of North America. Moreover, these snails are HOF _ il
`Q; frequent in open country and gardens, again on poor arid Fell ll
T Q as are the more tolerant species belonging to the ir=l}'?f·`l'fl ll
. genera, Mesodon and Triodopsis for example, and are found wiill *>
,; sporadically in urban gardens and waste places where eillfl
»·.‘ = genera of snails are almost invariably present, Stenot1‘e;u21l‘·Yli
. ld
3*
i
_A LAND SNAILS OF THE GENUS STENOTREMA ll
mm _ few exceptions abhors poor infertile soils, although limestone is
I hy no means necessary since some species don’t occur in lime-
stone regions at all. In general species of Stenotrema adapt
` themselves to clearing of forests, and are found in open country
whenever such clearing occurs on terrain which these snails
. occupied under the original forest cover. Certain species in-
i habit natural prairies (on good soil), but this predilection is
. lacking insofar as the short grass prairies of the western plains
Cl éllltl go, limi` there Stenotrema is confined to stream valleys. In pine
woods very few species (and these characteristic) occur. In-
» stances of S. fraternum living in pine woods have come to my
` attention in Michigan and Pennsylvania and also of S. hirsutum
t doin; the same thing in the latter state. The species listed under
New Q community 11 are pine forest species in the Southeast (and one
of them in the Ozarks).
. l`nder the treatment of the individual species mention will
he inode as to whether or not a given species is an obligatory i
¤0$Um iwipittole (never found except on stony or rocky ground) or not.
About thirteen of the thirty-three species and subspecies
‘ known appear to belong definitely in this classification. Most
mmm of the rest of the species frequently inhabit stony or rocky
sround, but are not bound to such terrain. Three of the most
llitlcljv spread species and ones that also occupy the glaCi3.t€Cl
1`€2‘i·»ns of North America, have only a minor link with rocky t
p shelter (S. barbatum, S. fraternum, S. monodon).
‘ Shecies of Stenotrema seem to appear in burned off localities
nosum along with other animals of the pyric (fire) succession. In fact
I inditiduals of burrowing species often survive fires, and some
have been taken alive only a few inches from spots where the I
inhabit ground is still hot. After fires survivors crowd under rocks, ;
culture logs. and other objects. Q
>\\'€‘{El`. I
forest# Q The ecological communities listed below are complete only
eastenz tor Alabama. In other regions the species will be assumed to j
not st ¤><. florida E ALA GA
. XERIC COMMUNITIES
9. IMI cew.1·-hardwoods.
A rl. deceptum N ALA TENN S. m0n0d0n aliciae
X S. exodon NE ALA S. spinosum ALA TENN A
S. exodon turbinella NE S. stenotrema
ALA TENN
Ny ia·n·tleaf pine w00ds. .
asl. rs. barbigerum ALA GA S. stenotrema V
{N S. magnifumcsum NC
I2. Unk barrens.
A $- hiFS¤tum NW ALA mmwdon aliciae g
NC I4. I’1·a1i1·ies.
S. m0n0d0n aliciae S. stenotrema
il 3
g .
i V
{ 14 GEOLOGICAL SURVEYfOF gABAI\/IA _—
, ARTIFICIAL COMMUNITIES _ 9dg*
C0..
15. Ruderal areas (open fields and roadsides).
S. barbigerum ALA NC GA S. ex0d0n turbinella ALA `
s. deceptum ALA s. timid;. GA g
_‘ S. edgarianum TENN S. chirsutum ALA TENN _ E`;
Shedvardsi TENN KY Shniagnifumosum NC (T lf
S. monodon aliciae Shstenotrema
16. Pastures (modification of 15). ,
7 j .l1c
S. barbigerum ALA NC S. monodon aliciae
S. hirsutum TENN S. stenotrema
Q Saumagnifumosum NC
I 17. Farmyards. \
<€.'('
T S. monodon aliciae N ALA S. stenotrema E TENN rim
A pill
18. Urban areas (gardens and vacant lots). ph;
i S. deceptum NE ALA S. inonodon aliciae ALA A llllf
g " S. hirsutum TENN VA TENN illtl
jr. S. magnifumosum NC (lll
L ‘ ati;
Al Economic value. Species of Stenotrema function in i.aturv I H I
i` as soil makers and scavengers. They feed chiefly on dead lcz1\‘€S ll?
f0l` lZl"l€ sake of ‘l1l1€ fungi that grow On thgmy and yedumg the lll,
" humus to nitrogenous material, It is likely that species thm ull
J inhabit culture areas of farms and urban sections serve tlw pd
same purpose, None of them are known to be garden pe>ls.
Enemies of these snails are small rodents, beetles, clliéllii
ja Evarthrus. but not the famous snail-eating carabid Cychrini. A5 Tl I
y ‘. has been pointed out in recent years by different obs·=i‘\`€l`F iu
fl l predatory snails of the genus Haplotrema attack these snails Ml
by penetrating the narrow keyhole-shaped aperture of the slwll ii;
but by boring through the wall of the shell and digesting out lllt ml
.· soft tissues externally. QU]
Abnormalities. The phenomenon of albinism is not zi iii;
striking deviation from the normal coloration, since the Sllll? W
_1 has ample pigment of the eyes in spite of the pale color if lllf th
shell. The following instances of albinism have been fouirli A
{Q
A
` LAND SNAILS OF THE GENUS STENOTREMA 15
edgarianum, Grassy Cove, Tenn.; S. edvardsi, Anderson, Sullivan
` C0., Tenn.; S. magnifumosum, Blount Co., Tenn. Murphy, N. C.;
, hirsutum, Grassy Cove, Tenn.; S. pilula, Sugarland Mt.,
LA Sevier Co., Tenn.; S. deceptum, Madison Co., Ala.; S. maxillatum,
‘ 1 Randon`s Creek, Monroe Co., Ala. A double parietal lamella was
Y found in a specimen of S. barbigerum, Murphy, N. C. A topotype
` . of S. brevipila (q. v.) was found to have the termination of the
parietal lamella joined directly to the inner denticle of the basal
peristonie by a calcareous growth. Sinistral examples have
I been found so far only in northern states (S. monodon, Ann Arbor,
. Mich.; S. fratenum, Licking Co., Ohio).
SYSTEMATIC CATALOGUE .
General discussion. The genus Stenotrema not only has
excellent characters, first of all in the aperture of the shell,
N and then in the hairy appendages of the cuticle, but also in the
pillar structure, that is to say, the pilaster pattern inside of the p
_ phallie chamber of the penial apparatus or penis. In using the .
JA pilastws as aids to classification it is important to realize that
althougli individuals may be sexually mature as to female organs i
i (protogynous), they may still be immature in the penial appar-
éltus, and this present a very attenuate pattern. Dissection of
mm Pl fen individuals will reveal a sufficient number of mature ,
CHVQS lltilles. Distortion resulting from preservation in strong 2ilCOl‘10l `
Q the U1` llllrni boiling may produce convexities on the SLl1`f&C€ of tl'1€ i
thHI lllllet wall of the chamber, that are not part of the true i>ilaSt€1` ~ .
re tire pattern.
is.
Zn using the shell characters of the genus for classification
hiefly *lls‘lll.lv immature individuals will be found to have such an
i. As attenuate apertural structure as to present a false picture. Fully
,,,.61-; Mlllll Lind even gerontic individuals posses the Hpe1`tLll`?1l SJE1`UC· ,
is my tufts lll full measure needed for determination. Pilsbry (Land i
· sléell llollusea of North America, 1940, pp. 640-641, fig. 400E) out-
ut the lines the nomenclature to be used for the structures of the aper-
ture and for the sculpture of the shell. In this paper I will use (
Stlllle terminology that is 3 modification of that of PilSb1‘Y, Zilld l
1 \.€,.._- - also that modifies seme terms used by myself in earlier publicat- i
, Simi lm (t€l`TY1S Which needed improvement). In this p3p€1` the ‘
,,{ die I term HtO0tll” as used by Pilsbry will be called "denticle", except
Hi. 5, that "Darietal tooth" (not even a denticle) will be more properly 1 .
`(
i 16 GEOLOGICAL SURVEY OF ALABAMA
designated as a "parietal lamella". The term "peristoine" mj » 1`Hll
·“ he substituted for "lip" as used by Pilsbry. The reader is yr. mill
i ferred to Plate 5, figure 6 for a diagram of the apertural stint. lall
P tures referred to in the keys.
1.
·· Although the general shape of the shell is mentioned under lm-
_ different species the matter of obesity is omitted from the deg. A .,,1
‘f criptions in the keys. Shells of various species become more obese . pe,
,Z (relative increase in width and decrease in the height of the A im
fl spire) as we proceed from upland to lowland habitats. This lioliis
` true not only as between one species and another but also withix; — 9
a single species whenever it occurs equally on uplands and in
Q.i stream valleys (e. g. S. monodon aliciae). The index of obesity e O,.
i has been computed for a number of species by dividing the height » its
' of the shell into the diameter, and by finding the mean of ;i
1 given population. This index is called the H, D or hei;.;l1t-tlia `
meter index. .
T Correlation between obesity and habitat stations has beat T`.
done by many workers such as C. C. Adams on the fi·eshwatev g me
%· snails, Io, and by Goodrich"‘ on Pleuroceridae (axial height of the dg,
g shell increasing proportionately from downstream to Ll}>Sf1'E;i111
I} habitats). A. E. Ortmann (Proc. Amer. Phil. Soc. 19 (1921112 A
cj 269-312) has shown this to be true also in bivalves. set
soi
The genus Stenotrema. Pilsby (pp. 577, 640-641) ai111i·l&‘ sh.
defines the genus Stenotrema Rafinesque 1819. The shell i= Pi]
conic-globose, subglobose, or carinate (keeled) and lens-sliapé ve
A (lenticular). The aperture is not only basal but also ti·ansi‘erSt als
The genitalia are typically polygyrid, but the phallic striicturv or
i· (phallus) of the penial apparatus is differentiated from mill t To
P ’»·. thicker than the apically located epiphallus. The spei·iiaatli¤~:» ta
has a slender duct. Genotype: S. stenotrema (Pfeiffer Nfl an
· sa
T Key to Stenotrema. The genus is divisible into two ‘y‘’ ell it
hi fined subgenera (if not actually two distinct genera). Pllflii l.
Lf broke it down into a number of groups, but substitution of
ji subgenera seems desirable owing to the fact that there €>ii‘Y
A tangible differences in genitalia (but possibly not of QENFVY 4 L
4-*_‘ *’“‘ ` N
i ’*‘References to these papers are: C. C. Adams, Mem. Nat. P»¤`1j1i¤»
, 1915, 12; 1-91; C. Goodrich, Occas. Pap. Mus. Zool., Univ. Mich., AOS j_
V " 295, 300, 1934-1935.
A *
·( .
I?
_
i LAND SNAILS OF THE UENUS STENOTREMA 17
·· W . i·giil;)_ and field observers have noted puzzling differences in
is W m[{A[lllQ` behavior as between the two. Actually there is no ever-
m.,_u._ lap lieixveen the subgenera in shell characters.
( 1. Ollter denticle present on the peristome. Inner half of basal
lllltiell — lerisinnie (lip) adnate, or if free, then submedian notch present
. I _
e des- tn inner rim of basal lip (but otherwise not necessarily so). I
obese Penis or Phallus slender, rather elongated, sausage-shaped; its
lf ill: length more than I/2 the diameter of the shell .__....c,Voicor.r.ori_.r...oo. . _or...oo_,.c . ,r.,,
}lUl‘_l‘ .....,»r,...,c . ..‘,......,,.e...,......v, . ,...‘...,.......,..,...».._...... . ...», S. gen. Stenotrema p. 17.
‘“tllliY ` 2. Outer denticle entirely lacking. Inner half of basal peristome
tlltl-lll free: notch never present on inner rim of basal peristome. Penis l
"’“_$ltY" (i1`l)l1illlLlS short, stout, club—shaped; less than, or at the most,
ll‘?l¥llY I its length I/Q the diameter of the shell ............................. . ............. . .... .. ......
l otal g W ........................................................._.............. S. gen. Euchemotrema p. 52.
lll-(lla}- I
· Subgenus Stenotrema Rafinesque, 1819. I
I be l 'l`}‘lll<;·=»»I species: Stenotrema stenotrema (Pfeiffer 1842). Raf—
l“_&[ff illescllws type was S. convexa 1819, but designated without a
Qt M definition (Pilsbry, 655).
h€1‘l* of shell carinate or strongly angular .................... .. ..... . ........
at YT .............................,___..._.___._____._l_______,._______,.___,__ . __._.. Sect. Caracollatus, p. 19.
nf FXEY
g€ll€l`l» l· P¤1‘il>hery rounded Or at the most bluntly angular ........... .... (2) l
W: cg _ 2· Illll@1` half of basal peyigtgiyie freeing ___..__,.. Sect. C0l`|UttH, D- 49·
mi 2- llIIl€l‘ half of basal peristome &(lI1?it€·
l I
_. I
I I I
[
g 18 GEOLOGICAL SURVEY OF ALABAMA H
g Basal peristome lacking a notch on inner rim; having a lamina 1 {us
within the aperture parallel to rim of basal peristome t,t.,.t.. . . - the
5, t,.i.._.i..,.,t.,, .,.,tt......_t...t,ti,i.......i....._,.._....i.ii. . t.._.._t,.ti..r. .. ._..,..,.i..... Sect. Maxillifer, p. Bl. .
Q J lla
pr 3. Basal peristome having a submedian notch, and never double On
V` rimmed. (4)
4. Interdenticular sinus shallow and very widely curved. Ontu A
`* . .
-· denticle angular or weakly angular, never thickened or prominent. TY
but instead widely diverging from the bottom of the intcrdenti-
A cular sinus ....................._._..._........................ . ................. . ..... Sect. Stenostoma, p, 2] 1-
-, . . . Q 2.
L 4. Interdenticular sinus more or less rounded, sometimes deeply i (.0
so. Outer denticle stout, prominently angular, or at least strongly °
Q rounded, and not widely diverging from the bottom of the in- ‘ 3
fw terdenticular sinus .........._... ......................................... Sect. Toxotremzr. p. 38. _ 3,,
In the following guide to the genitalia of the sections ofthe ` (ii
subgenus Stenotrema the sections are listed in their proper sys- V liu
.3 tematic order: '
· i 3.
Caracollatus. Pilaster pattern more or less complex in the · lor
apical region, but never loop-like or biramous. Pilasters thick- he
`Q ened in the apical region, sometimes very much so, and fused ·
, _`[ apically, or if not fused apically, then each pilaster ot equal _ y)
thickness, and one overlapping the other; without a cominissuie ~·
(ll . .
l between the two main pilasters. o 4
35 ·
'li
-= . . . . . l 2
gl Stenostoma. Pilaster pattern loop-like at least in part, ¤»1‘ €l$€ I
` biramous. Pilasters slender and fused in the apical region, <¤i‘ yl
n else if one pilaster noticeably thicker than the other. tlitfl in
separated in the apical region; no commissure between the TW'? lu
g main pilasters, but in one case, however, fused in the miclzwiie- ,
. 1.
if T0X0ll`€ITl2l. Pilaster pattern irregular-, and at least not l00lt y at
like or biramous. Pilasters thick, at least one of the two, i1`1'¤Qul*“`
and nodose or lobate; fused in the apical region, or else if ll"‘l "-
yj fused or if one pilaster overlapping the other, then one l*ili‘~*l?l' _
jin i tl\lCke1‘ than the other; commissures joining the two millll ')‘
, A, pilasters in most cases. · di
ih ,_
l C0hl1tl21. Pilaster pattern simple, or vaguely loop-like lll il? A it
21lJ1CZll half. Both pilasters very attenuated in the niiClZ0ll*i l`
5
Y?
_
U LAND SNAILS OF THE GENUS STENOTREMA 19 ~
ninu 1 fused or unfused in the midzone; fused or widely separated in
_ . the apical region.
Bl, .
’ llaxillifer. Pilaster pattern irregular, and with a double apex.
·ulili· One pilaster pendulous lobate, longitudinally grooved_
Section Caracollatus, new
’lllZ€l'
Type species: Stenotrema spinosum (Lea 1830)
ient.
enti-
QT l. Submedian notch on inner rim of basal peristome present. (2)
wl" 2. Submedian notch a small V-shaped cut. Appalachian species.
ngly J (O)
g A Pcriphery carinate. Aperture narrow. Parietal lamella high
" "“‘ » and more prominent than basal peristome, terminated by a hook.
` _ Butriiss present, joining the termination of upper peristome
lllw (lip) without a sulcus between. Upper denticle strongly angu-
SYS- V lar . .................. . .........Y.....,........................................_ . .......,. S. edgarianum, p, 23.
i 3. Pcriphery angulate. Aperture gaping. Parietal lamella shal-
tlie · low, less prominent than basal peristome; not terminated by a i
nick- hook. Butress absent. Upper denticle weakly angular .....................
`used — ,...____, . ..._,. . ...._.__,,,,___________._.__,_____.______,___._____....____,____,.._________,__._,_, S, edvardsi, p, 26, `
equal _ p i
=sure 2. Submedian notch U-shaped. Ozarkian species. (4) ·
4. Basal peristome and arc of peristome narrow. Body whorl
else . ll21\`l1i}1 three rows of peristracal fringes ........,............ S. pilsbryi, D. 24. i A
Biiéall perlstome and are of peristome Wide. Body WhOI`l lack-
W6 me rutucular fringes; with Oy without short hairs on the angw ;
me " lute periphery __._________,_____e_._,_4_____4________________,_,__..,__.,_________,_.___.._._._... S. labrosum, p. 25.
l. Submedian notch on inner rim of basal peristome absent, or
loci; , at nnist a weak, shallow bay. (5) ’
gui .
l “'“l "· P<‘l`ll>h€1‘y angular; shell conoid lens-shaped S. edvardsi. p. 26.
aster
niziiii "- P1‘essed spi;-e_ ((5)
l tlzr ° li Eéirietal lamella more prominent than basal D€Ti$t0m€· Outer
ZOIN? h