NO. 2 BRACHIOPOD SUPERFAMILY STENOSCISMATACEA GRANT IIO,

USNM

142176, 36539) ; Chester, at

M. &

O. Railroadbridge, 2miles north of Baldwin,

Randolph

County, 111. (76 specimens

USNM

142191) ;lowerpartofFayetteville Shale,2milesnorthof Habberton, Ark. (35 specimens

USNM

142164) ; lower part of

Glen Dean

For- mation,

on

road

between

Cloverport

and

Mattingly, Breckinridge County,

Ky.

(52 specimens

USNM

142192, 93) ; Chester, near bridge over Prairie

du Long Creek

3.3 miles north of

Red Bud,

111. (13 specimens

USNM

142194, 95) ;

upper

part of Fayetteville, about 3 mileseast of Elkins,

Ark.

(1 specimen

USNM

142196) ; Chester, at

Tar Park

Post Office,

Ky.

(3 specimens

USNM

142197); Chester, Buffalo

Wallow

section, Cloverport,

Ky.

(2 specimens

USNM

142198) ; Chester, at Rileys,

Randolph

County, 111. (9 specimens

USNM

142199,

48892)

;

Glen

Dean, center of

NW.J4,

^{sec. 13,}

T-

35-N, R-12-E,

in railroad cut 1 mile southeast of

Red

Rock,

Derry

County,

Mo.

(2 specimens

USNM

142200) ; St. Louis Limestone,

Pope

County, 111. (2 specimens

USNM

142201) ; Chester,

Evans-

ville, 111. (5 specimens

USNM

^{142202) ; Chester,}

on Hardinsburg Road

to Stephensport,

Ky.

(30 specimens

USNM

142203-5, 37867) ;

Chester, Chester, 111. (7 specimens

USNM

^{142206) ; lower part}

of St. Genevieve Limestone,

Cardens

Crossroads,

6

^miles south of Marion,

Ky.

(2 specimens

USNM 48888)

; Chester near base of section at Smithland,

Ky.

(8 specimens

USNM 48891);

Chester, middle of section at Smithland,

Ky.

(3 specimens

USNM ⁴⁸⁸⁹⁰⁾

;

Chester,upperpartofsectionatSmithland,

Ky.

(37 specimens

USNM

48898)

; upper part of Chester, north of Caneyville Quarry,

Grason

County, Leitchfield,

Ky.

(5 specimens

USNM

142207) ; middle part of Chester, 4.5 miles east of Princeton,

Ky.

(7 specimens

USNM

48887)

; middle part of Chester,

4

miles east of Scottsburg,

Ky.

(9 specimens

USNM 48894)

^; topofChester, King'sStation, Crittendon County,

Ky.

( 1 specimen

USNM 48889)

; top of Chester,

Montgom-

ery Switch, Caldwell County,

Ky.

(10 specimens

USNM 48895);

upper part of Chester, 1 mile west of

Montgomery

Switch, Caldwell County,

Ky.

(20 specimens

USNM

^48893).

Age. —

^LateMississippian

(Meramec

toChester)

.

COLEDIUM GLOBULINUM

^(Phillips)

Plate18,fig.2

Terebratula globulina

PHILLIPS,

J., 1834, Encyclopedia Metropolitana; Geol., vol.4, pi. 3, fig. 3, {fideDavidson, 1858).

Terebratulaseminula

PHILLIPS,

J., ibid., p.222,pi.12, figs.21-23.

Camarophoriaglobulina (Phillips)

DAVIDSON,

T., 1858,Monogr. Brit. Perm.

Brach. (pt. 4),p.27, ^pi. 2,figs. 28-31;

DAVIDSON,

T., 1863, Monogr. Brit.

Carb. Brach., (pt. 5), ^p. 115, pi. 24, figs. 9-22;

DAVIDSON,

T., 1863, Ap- pendixtoCarb.

&

Perm.Monogrs.,p.268,^pi.54, figs.20-25.

120

SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOL. I48 Stenoscismaglobulina (Phillips)

BRANSON,

C. C, 1948, Geol. Soc. America

Mem.

26,p.524 (synonymyonly).

Shell small for genus, moderately biconvex to subglobose; outline subelliptical to subpentagonal, length

and

width nearly equal;

com-

missure uniplicate; fold moderately high at anterior but not standing

much

above flanks, beginning about

4 mm.

anterior to brachial

beak

(proportionately far

forward

in so small a shell) ; sulcus shallow, hardly depressed

below

^level offlanks; costae

numbering two

orthree

on

fold,one fewerinsulcus,

one

or

(more commonly) none on

flanks

;

growth

lines not observed;

growth

laminae weak, widely spaced;

valves meeting nearly perpendicularly at anterior, without trace of stolidium.

Pedicle valve

most

strongly

convex

just anterior to

beak

region;

beak

sharp, suberectto slightly incurved; delthyrium apparently with- out^deltidialplates^;

foramen

notpenetrating

apex

ofbeak.

Brachial valve

more

strongly

convex

; greatestconvexity nearpos- terior,longitudinalconvexity lower

toward

anterioralongfold.

Pedicle valve interiorwith dental plates

forming

spondylium, ses- sile in

extreme

apex, then elevated

on low median

septum, extending anteriorlyaboutone-third lengthofvalve.

Brachial valve interior with small hinge plate at posterior;

cam- arophorium

beginning as slender-sided trough

on

top of

septum

in posterior,curvingventrally,extending aboutone-third length of valve

;

intercamarophorialplatenotobserved,probablypresent.

Comparisons.

— Coledium

globulinum is characterized

by

^its small size, globose shape,

few

costae,

and

its

camarophorium

thatbegins as atrough, not a knob, inthe

apex

ofthevalve. It isthe smallest

known

species of the genus,

and

is

much

smaller than the other species that occursinthe Permian,C.

crassum (Hamlet) from Timor.

Its shapeis

most

likethat of C.

explanatum (McChesney) and

C.

obesum

(Clark), but it is smaller

and

less stronglycostate, especially

on

the flanks. It also resembles C. bowsheri (Cooper), differing in its smaller size,

narrower and

less pentagonal outline,

and

in the presence

on some

specimensofcostae

on

theflanks.

Discussion.

— The

U.S. National

Museum

has four specimens of C. globulinum

(USNM 96284) from

the

Permian

of Tunstall, near Sunderland, England, a locality cited for the species

by Davidson

(1858).

These

confirm the suspicionaroused

by

Davidson's

and

Phil- lips' (1836) descriptions

and

illustrations that the species belongs to Coledium.

As

such, it is one of the youngest

known

species of the genus: only

H. crassum (Hamlet) from

the island of

Timor

also is

known from

thePermian.

Davidson

(1863, p. 116, p. 268) concluded

from

examination of

NO. 2

BRACHIOPOD SUPERFAMILY STENOSCISMATACEA GRANT

121 Phillips'specimens

and from

his

own

collectionsthat C.globulinumin- cluded specimens that Phillips

had

called Terebratula seminula. I ac- cepthisopinionin this matter,

and

include the

name

in the

synonymy

ofC.globulinum.

COLEDIUM OBESUM

(Clark)

Plate16, figs.2-2c;figure29

Camarophoria obesa

CLARK,

T.H., 1917, Harvard Mus. Comp. Zoology, Bull.

61,No.9,p.373,pi. 2,figs. 13-24, textfig.3.

Stenoscisma obesa (Clark)

EASTON, W.

^H., 1962, U.S. Geol. Survey Prof.

Paper348,p.41,pi. 4,figs.24-27.

NOT

Stenocisma obesa (Clark)

SHAW,

A. B., 1962, Journ. Paleontology,vol.

36, No.4, p.633,^pi. 97,fig.27-31; pi.98, fig. 6-8,textfig. 1, (Atribonium aff.

A.bisinuatum (Rowley)).

Original description (Clark, 1917).

—

^{Shell small,} subglobular in form, subcircularto subpentagonalinoutline, longerthanwide, wider than thick.

Both

valves are strongly

convex;

the pedicle valve is the

more

strongly arched longitudinally, the brachial valve transversely.

Inthe pediclevalve the beakis

prominent and

overhangs the brachial valve considerably.

There

is adistinct but not strongly

marked

sinus

on

the pedicle valve, within

which

is a raised

median

plication.

On

either sideof the sinusare

two

plications, onlythe pair bordering the sinus achieving

any

prominence; occasionally the only evidence of the outer plication is a sinuosity in the lateral margin.

The

brachial valve is characterized

by

a short

and

not

prominent

fold divided

by a median

furrow.

On

each side there

may

be

one

or

two

short plica- tions.

The

fold, sinus,

and

plications

on

bothvalvesare short, not ex- tendingonehalfthelength of thespecimens.

Internally,the pediclevalve

shows

apairofdental lamellaenearthe beak, supported

by

a

median

septum.

The

lamellae are continued an- teriorlyinto a spondylium, well raised

from

thefloorofthevalve.

The

brachial valve has a slightly longer

median septum

supporting both hingeplate

and

cruralium

(camarophorium). The

hingeplate isshort,

and

thecruraliumextends ashort distance

beyond

theseptum.

The

surface ofthe valve is

unornamented

save for lines of

growth

atirregularintervals.

Supplementary

descriptiveremarks.

— ^The

^beakofthe pediclevalve isshort

and

sharp, erect to slightly incurved; the delthyrium is open, normally not completely filled

by

the brachial

umbo, and

unobstructed by deltidial plates; the

foramen

penetrates the

apex

of the beak.

De-

spite Clark's statement to the contrary,

most

specimens are nearly equalinlength

and

^width,orslightlywider thanlong.

The camarophorium

of the brachial valve interior is short for the

122

SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOL. I48 genus,

most

similar to that of C. bowsheri (Cooper),

and

is strongly curvedlongitudinally,incontrasttothenearly straight

camarophorium

ofspeciesofAtribonium.

There

is

no

trace ofa stolidium

on any

of the

numerous

specimens inthe

Easton

(1962) collection,

and

the

form

ofthe anterior

commis-

sureistypical ofthat of speciesin

which

thestolidium is absent.

Comparisons.

— Coledium obesum

ischaracterized

by

itssubglobular shape, sharp, suberect beak, with

open

delthyrium

and foramen

that penetrates the apex,itsshortbut stronglycurved

camarophorium, and

especially

by

^its

few and

gentle costation of fold

and

flanks. It

most

nearly resembles C. bowsheri

(Cooper)

ingeneral shape, differing in its less transverse outline,

and

fewer

weaker

costae. It also resembles C.

explanatum (McChesney),

but is

somewhat

smaller

and

^its costae,

on

both fold

and

^flanks, are

much

weaker. Its

maximum

^size is only about halfthat of C.

erugatum

n. sp. or C.

torvum

n. sp.; its costae further distinguishit

from

theformer,^itsfewer

and weaker

costae

from

the latter. It is smaller, wider,

and

less triangular in outline than C.

rhomboidale (Hall

and

Clarke)

and

C.

therum

(Walcott),

and

its costae areweaker. It issmaller, less convex,

and

has

weaker

costae

on

thefoldthanC.cestriensis (Snider)

.

Remarks. — ^Shaw

^{(1962, p. 633) described specimens}

^from

^the

Lodgepole Limestone

of

Montana under

thedesignationof

Stenocisma

(sic) obesa (Clark).

Study

of his illustrated specimens in the U.S.

National

Museum

collection

shows

that they

have

the flattened ante- rior,

and

the general

form

that typify species of Atribonium,

and

are not closely related to

Coledium

obesum.

Shaw's

specimens probably belong to a

new

species that is related to

Atribonium

bisinuatum

(Rowley). He

suggestedthat his

new

species

Stenocisma

uniplicatum

Shaw

probablyisa variant of theonethathe called5. obesa, but that

itis stratigraphicallysegregated. Thisidea is corroborated

by

the fact that therangeofvariation oftheclosely related

A.

bisinuatum

(Row-

ley) includes specimens that resemble

Shaw's two

categories {see Weller, 1914, pi. 23).

However,

variants of the Mississippi Valley population

may have become

established as separate species in

Mon-

tana,

and

aslong as the

two forms

are stratigraphically segregated, I

agreewith

Shaw

thattheyshould be recognizedasdistinct.

Growth. — ^Trends

^of

^growth

^{in this} species aretypical forthegenus, with points

on

the width scattergram (fig. 29) clustered narrowly along a straight line,

and

those

on

the thickness scattergram

more

widely spread along a curve of gentle acceleration. Small shells are Fig. 29.

—

^{Scatter diagrams of dimensions of Coledium} obesum (Clark) from Easton's (1962) locality13414, GoldenValley County,Mont.

o

3 2 3- 4-

^ ₉

10

II

12 13-

o

o o

o

8 %*s

o o

o O o

o

5h ^{o°q5> o}

o

o o o

o

LENGTH (MM)

*

9 10

II

12

o

J 1 1 1 1 1 1 1 1 I

o

o o o

o

51-

%

o

.8?

°o ^°

«$°

8

o O00 o

cP

° on

o

Fig.^29.

—

(Seeoppositepageforlegend.)

123

124

SMITHSONIAN MISCELLANEOUS COLLECTIONS

VOL. I48