Procambarus (Girardiella) steigmani, a new crayfish (Decapoda: Cambaridae) from a long-grass prairie in northeastern Texas

8 Pages·1991·4 MB·English

PROC. BIOL. SOC. WASH.
104(2), 1991, pp. 309-316
PROCAMBARUS (GIRARDIELLA) STEIGMANI,
A NEW CRAYFISH (DECAPODA: CAMBARIDAE)
FROM A LONG-GRASS PRAIRIE IN
NORTHEASTERN TEXAS
Horton H. Hobbs, Jr.
Abstract.—Procambarus {Girardiella) steigmani, a crayfish which appears to
be a habitual (primary) burrower, is described from a single locality on the
Parkhill Prairie, in the Trinity River watershed of Collin County, Texas. Its
closest relative, from which it differs in possessingasymmetrical first pleopods
in the male and a highly sculptured annulus ventralis in the female, is P. (G.)
regalis which has been reported from the Ouachita and Red river basins of
southwestern Arkansas.
Described herein is Procambarus (G.) rical first pleopods, a feature apparently
steigmani, thethirdpreviouslyundescribed unique in the subgenus.
member of the subgenus Girardiella to be
recognized since Hobbs & Robison (1988)
Procambarus (Giradiella) steigmani,
reviewedthe occurrence ofthegenus in Ar-
new species
kansasandpresentedakeyandillustrations
Figs. 1, 2
to aid in the recognition of the 10 then-
known members ofthegracilisgroup ofthe Crayfish.—Eig, 1990:1A, 5A, unnum-
subgenus. Procambarus(G.) kensleyiandP. bered color photograph.
(G.) nigrocinctus, both rather distantly re- Diagnosis.—Body pigmented, eyes well
latedtoP. (G.)steigmani, were subsequent- developed. Rostrum lacking marginal
ly described by Hobbs (1990) from the spines, tubercles, and median carina. Car-
Neches River basin of eastern Texas. The apace without cervical spines or tubercles.
newspeciesiscloselyalliedtoP. (G.) regalis Areola often linearbut never less than 45.5
Hobbs & Robison, 1988, from southwest- times as long as wide and constituting 37.4
em Arkansas, sharing so many features in to 41.9 (JT= 40.1) % oftotal length ofcar-
common with that species that I am tempt- apace (44.6 to 47.6, X = 46.0% ofpostor-
ed to recognize it as a subspecies ofthe lat- bitalcarapacelength). Suborbitalangleweak
ter. Until more is known about the ranges and obtuse. Hepatic and mandibular areas
of the two, the treatment proposed here weakly tuberculate; branchiostegal spine
seemsto me, however, tobebasedonfewer absent. Antennal scale about 2.4 times as
assumptions. long as broad, widest distal to midlength.
An error is present in the key mentioned Ventral surface of palm of chela punctate
above (Hobbs & Robison 1988:404): at the mesially and laterally (rarely with single
end ofcouplet 2, "6" should read "7" and, smalltubercle ventromesially), notubercles
at the end ofcouplet 5, "6" should replace onventral surfaceofdactyl. Ischium ofthird
"7."Usingthiskeywiththecorrectionsnot- pereiopod of first form male with simple
ed, P. (G.) steigmaniwould be identified as stronghookoverreachingbasioischialartic-
P. (G.) regalis from which it may be distin- ulation; hook not opposed by tubercle on
guished readily by its possessing asymmet- corresponding basis; coxa offourth pereio-
310 PROCEEDINGSOFTHEBIOLOGICALSOCIETY OFWASHINGTON
m
Fig. 1. Procambarus {Girardiella) steigmani, new species (holotype except c, ffrom morphotype, and i,
fromallotype):a,Lateralviewofcarapace;b,c,Mesialviewoffirstpleopod;d,Antennalscale;e,Basalpodomeres
ofthird, fourth, and fifthpereiopods; f, g, Lateral view offirstpleopod; h, Cephalomedian lobe ofepistome; i,
Annulus ventralisandadjacent stemites;j, Dorsal view ofcarapace; k, 1, Caudal view offirst pleopods; m, n,
Dorsalview ofdistalpodomeres ofcheliped.
VOLUME NUMBER
104, 2 311
Fig. 2. Dorsolateral view of paratypic male, form I, Pwcambarus (Girardiella) steigmani, new species,
illustratingcolorpattern.
pod lacking caudomesial boss. First pleo- ally. Second abdominal segment narrower
pods of first form male reaching coxae of than thorax. Areola linear along most ofits
third pereiopods, asymmetrical, bearing length. Cephalic section of carapace 1.2
tuberculiform proximomesial spur, angular times as long as areola, latter comprising
sloping shoulder at base of terminal ele- 41.9% oftotal length ofcarapace (47.4% of
ments, and lacking subterminal setae; ter- postorbital carapace length). Surface ofcar-
minal elements, all at least partly sclero- apace smooth to punctate dorsally, weakly
tized, consisting of: (1) straight to slightly granulate ventrolaterally and sparsely tu-
curved, spiculiform mesial process over- berculateinhepaticandmandibularregions.
reachingotherterminal elements; (2) short, Rostrum with thickened margins tapering
acute,cephalodistallydirectedcephalicpro- from broad base to short acumen, latter in-
cesssituatedatcephalolateralbaseofmesial distinctly delimited basally; slightly up-
process; (3) strong comified obliquely flat- turnedtip ofacumen reachingmidlength of
tened and caudodistally directed central penultimate podomere of antennular pe-
projection; and (4) caudal element consist- duncle; dorsal surface concave anteriorly
ing ofrounded, obliquely disposed, lamel- becoming subplane toward base and with
liformlobewithmesiodistalangleandsmall, fewconspicuouspunctationsbetweenthose
adnate, thumb-like lobe on caudomesial on mesial flank ofridges; subrostral ridges
base of latter. Central projection slightly moderately prominent and evident in dor-
overreaching caudal element. Female with sal aspect to base of acumen. Postorbital
annulus ventralis freely movable, slightly ridges prominent, swollen posteriorly,
broader than long, subsymmetrical in out- deeply grooved laterally but weakly elevat-
line; deep cephalomedian trough leading to ed dorsally, and lacking spines and tuber-
sigmoid sinus ending on caudal wall ofan- cles. Paired posterior gastric prominences
nulus; anterolateral prominences highly moderately conspicuous. Suborbital angle
sculptured and bearing prominent tuber- obtuse. Branchiostegal and cervical spines
cles. Preannular plate obscure; postannular lacking.
sclerite weakly tapering anteriorly and with Abdomen shorter than carapace. Pleura
anterior third sloping conspicuously dor- of third through fifth segments broadly
sally; first pleopods present. rounded ventrally. Cephalic section oftel-
—
Holotypic male,form /. Cephalothorax son with 2 spines on right (3 on left) cau-
(Figs, la, j, 2) subovate, compressed later- dolateral comer, more lateral one on both
312 PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
sidesimmovable.Cephaliclobeofepistome ofcorneous tip offinger; lateral surface of
(Fig. 1h) campanulate in outline with small fingerroundedandbearingrowofsetiferous
apical projection; elevated margins thick- punctations. Opposable margin of dactyl
ened, median area subplane; main body of withdistinctexcisionatbasesupportingrow
epistome with fovea; epistomal zygoma of 3 tubercles followed by row of 5 in an-
arched. Ventral surface ofproximal podo- tepenultimate fourth offinger, single rowof
mere of antennular peduncle with strong minutedenticlespresentbetweenanddistal
spine near midlength. Antennal peduncle to latter row; mesial surface offinger with
lacking spines and prominent tubercles on 2 (left with row of 3) tubercles near base
three proximal podomeres; flagella broken followed by row ofsetiferous punctations.
but reaching second abdominal tergum in Carpusofchelipedlongerthanbroadwith
morphotype. Antennal scale (Fig. Id) 2.4 obliquefurrowdorsally; mesialsurfacewith
times as long as wide, broadest distal to 1 large, conical, corneous tubercle and 2 ru-
midlength; greatest width of lamellar area dimentary ones proximal to it; dorsomesial
about twice that ofthickened lateral part. distal angle corneous, dorsal surface punc-
Third maxilliped extending anteriorly to tate; ventromesial surface with arc of3 tu-
level of ultimate podomere of antennule; bercles leading to more mesial one of2 sit-
ventral surface moderately setose, setae on uated on ventrodistal margin ofpodomere.
mesial halfofischium and row on ventral Merus ofcheliped with 2 oblique dorsal
surface of merus conspicuous, those ex- rows of 3 tubercles each, two distalmost
tendingmesiallyfrom sublateralrowsmall- members larger than others and subacute;
er and fewer in number; merus not com- dorsomesialdistalmarginproducedin con-
pletely obscured by setae in lateral aspect. spicuous, weakly scalloped prominence;
Right chela (Fig. In) subovate in cross ventral surface with mesial row of 12 tu-
section, depressed; width ofpalm 1.3 times bercles and lateral one of 6, only 1 or 2
lengthofmesialmargin;latterslightlygreat- tubercles not in linear series. Ischium with
er than V3 length of chela; except mesially 1 (2 on left) tubercle ventromesially.
and dorsomesially, palm mostly punctate Hookon ischium ofthirdpereiopod(Fig.
although dark coloration ofsmall, recessed le) simple, robust, overreaching basiois-
tubercles over much ofdorsolateral surface chial articulation, and not opposed by tu-
presenting erroneous first impression ofits bercle on corresponding basis. Coxae of
beingstronglytuberculate. Mesialsurfaceof fourth and fifth pereiopods without cau-
palmwithrowof7 cream-coloredtubercles domesialboss, mesialcaudoventralangleof
flanked dorsolaterally by irregular row of8 that offifth with prominent tubercle.
almost black ones, and arc of 6 dark ones Sternum between third, fourth, and fifth
situatedmorelaterally; notuberclespresent pereiopods comparatively shallow; ventro-
on ventral flank of mesialmost row. Both lateral margins with plumose setae obscur-
fingers with poorly defined median longi- ing much offirst pleopods.
tudinal ridges dorsally and ventrally; ridges First pleopods (Fig. lb, g, k, 1) as de-
made evident largely by bordering punc- scribedin"Diagnosis." Setaeatcaudalbase
tuations. Opposable margin offixed finger splayed as in Procambarus (G.) regalis.
with row of 5 (4 on left) tubercles (distal- Uropods with mesial lobe ofbasal podo-
most largest on finger) on proximal fourth mere produced in distally projecting spine;
of finger, followed by row of 4 (3 on left) mesial ramuswithdistomedian spine small
smallonesalongmiddlethird,andabraded, and premarginal; distolateral spine present
more ventral, large one at base of distal on mesial and lateral rami.
fourth offinger; single row ofminute den- Allotypic female.—T)\^Qrmg from holo-
ticlesextendingfromlargesttubercletobase type, other than in secondary sexual fea-
VOLUME 104, NUMBER2 313
tures, in followingrespects: tubercles in he- Table 1.—Measurements (in mm) of the primary
paticandmandibularregionsnotnumerous typesofProcambarus(G.) steigmani, new species.
but conspicuous; anterior extremity ofros-
Morpho-
trum rounded, not forming apical promi- Holotype Allotype type
nence; dorsal surface of rostrum concave
Carapace:
posteriorly to base, subrostral ridges evi-
Entirelength 28.4 32.9 24.2
dent in dorsal aspect to base ofapical cur- Postorbital length 25.1 28.9 21.2
vature; postorbital ridges terminating an- Width 12.8 14.9 10.6
teriorly in minute corneous tubercles; very Height 13.1 14.6 11.0
small branchiostegal spine present on right Areola:
side; 2 or 3 tubercles present in position Width linear linear linear
occupied by cervical spines in many cray- Length 11.9 13.4 9.5
fishes;cephalicsectionoftelsonwith2spines Rostrum:
in each caudolateral comer; (right chela re- Width 4.3 4.5 3.3
generated exemplifying usual short mesial Length 4.4 4.7 3.8
margin ofpalm and comparatively straight Chela:
opposablemarginsoffingers)leftchela(Fig. Length, palm mesial
1m) with opposable margin offixed finger margin 7.7 7.8 6.7
like that of left member in holotype; op- Palm width 10.2 10.0 7.1
Length, lateral
posable margin ofdactyl ofchela with ad-
margin 22.2 22.0 15.3
ditional tubercle situated opposite distal, Dactyllength 13.0 13.2 9.1
moreventraloneonfixedfinger;mesialsur- Abdomen:
face ofcarpus ofcheliped with small tuber-
Width, second
cleatproximoventralbaseoflargetubercle; segment 9.7 11.6 9.1
prominence on distal dorsomesial margin Length, total 25.9 28.9 21.4
ofmeruswith2distinctscallops; dorsalsur-
face of merus with 8 tubercles, only 1 of
whichconspicuouslylargerthanothers. For comer; cephalomedian projection of epi-
measurements see Table 1. stomeminute; 8tuberclesinmesialmostrow
Annulus ventralis (Fig. li) as described onmesialsurfaceofpalm, 6inadjacentrow,
in "Diagnosis." Preannular plate membra- and 5 or6inmorelateralcurvedrow;dorsal
nous, not clearly delimited posteriorly; longitudinal ridge well defined on dactyl;
postannularscleritebroadbasally,gradually tuberclecountonopposablemarginoffixed
taperinganteriorlywith apicalthird sloping finger 3 and 6 on right (tubercles abraded
conspicuously dorsally and when pressed on left), 3 and 4 on that of dactyl of left
against annulus foreshortened so that an- chela(probablyalsoondamagedright);dor-
terior margin appearing broadly rounded. sal distomedian angle of carpus produced
First pleopods comparatively well devel- in short spine, and 2 small spines between
oped,reachingatleastmidlengthofannulus mesial and ventromesial spines; tubercles
when abdomen flexed. on dorsomesial distal prominence ofmerus
Morphotypic male, form //.—Differing more clearly defined. Hook on ischium of
from holotype in following respects: areola third pereiopod very weak, not nearly
shorter,constitutingonly 39.3%ofcarapace reaching basioischial articulation; tubercle
length; apexofacumenalmostreachingdis- onventralcaudomesialangleofcoxaoffifth
tal margin ofpenultimate podomere ofan- pereiopodreducedinsize. Firstpleopod(Fig.
tennularpeduncle;branchiostegalspinesand Ic, f) with less conspicuous shoulder on ce-
cervical tubercles weak; cephalic section of phalic surface, stouter mesial process, ce-
telson with 2 spines in each caudolateral phalicprocessnotdifferentiated from poor-
.
314 PROCEEDINGSOFTHE BIOLOGICALSOCIETYOFWASHINGTON
ly defined processes of central projection, olive. Third maxillipeds mostly pinkish
and lamella and thumb-like parts ofcaudal cream.
element less distinctly defined. Thecolorpatternoftheallotypeisalmost
—
Color «o?^5. Holotype (Fig. 2): Domi- identicaltothatofthemale,butthecoloring
nant colors cherry red and pale blue. Car- differs markedly. Carapace with dorsum
apacecherryreddorsally, slightlypalerfrom chocolate brown setting off"tannish cream
posterior level ofpostorbital ridges anteri- postorbitalridgesandrostralcarinae. Terga
orly;ridges,lateralrostralcarinae,andpaired of abdomen reddish brown and pleura
spots on posteriorgastric region vermilion. cream. Uropods and caudal section oftel-
Cervical groove and mandibular adductor son pale pinkish tan, mesial ramus ofuro-
areas dark reddish brown. Orbital region pods lacking dark caudomesial splotch. Pe-
dark brown suffused with red; hepatic re- reiopods as in holotype except lacking
gion dark red dorsally quickly fading an- pinkishsuffusion.Themorphotypeborethe
teroventrally to pink, lavender, and over same coloration as the holotype; however,
antennal and mandibular regions very pale the reds were more subdued.
blue. Branchiostegites with dorsal red area ^zz^.—The largest specimen available is
sharply set off"from lateral pale blue region a first form male having a carapace length
mm
alonglinefromlevelofsiteusuallyoccupied of37.0 (postorbitallengthof32.7 mm).
by cervical tubercle to dorsal end ofcaudal The smallest first form male has corre-
flange. Marginal ridge, caudal flange, and sponding lengths of 28.3 and 25.0 mm.
caudalridgedarkbluishgray.Dorsalsurface Measurements are not available for either
ofabdomenslightlypalerredthanposterior ovigerous females or ones carrying young;
dorsum of carapace; second through fifth for those ofthe primary types, see Table 1
—
terga with paired dark purplish red, cau- Typelocality. Parkhill Prairie, a 52 acre
dally-divergentspotsdorsolaterally. Lateral tractofgrasslandintheTrinityRiverbasin,
limitsofsametergamarkedbyarchedpaler 9.4 miles (15 km) north of U.S. Highway
purplish red marks abutting pink pleura. 380 off State Highway 36, Collin County,
Telson and uropods red, rami oflatterwith Texas (33°16'N, 96°18'W). The soil on the
red fadingtowardborders; dark splotch sit- Prairiebelongstothe Houston Serieswhich
uated caudomesially on mesial rami. Dor- consists of calcareous clays that here are
sum ofmerus and carpus ofcheliped red- shallowlytodeeplyeroded.Amongthecon-
dish brown with bluish to lavender blush; spicuous grasses are Andropogon gerardii,
carpuswith large distomesial spineanddis- Schizachyrium scoparium, Tripsacum dac-
tomesial angle pinkish cream. Dorsal sur- tyloides, Sorghastrum nutans, Bouteloua
face ofpalm ofchelatan; area flankingbase curtipendula, andPanicum virgatum. Inthe
ofdactyldarkenedbybluishsuffusion;most spring, the wildflowers include the Indian
tubercles and punctations very dark, but paintbrush, White winecup, and Wild pe-
proximodorsal articular condyle and me- tunia and, in the fall, Maximilian Sunflow-
sialmost row oftubercles on palm pinkish er, Ironweed, andasters. Therethiscrayfish
cream. Bothfingerspalebluewithcreamon along with representatives ofProcambarus
proximalflankofcorneoustips. Remaining (Girardiella) curdi Reimer, 1975, occupy
pereiopods pinkish cream with bluish suf- burrows that descend to an unknown depth
fusiononmerusandcarpus,darkestatjunc- belowthe surface. The burrows are marked
tions of these podomeres. Ventral surface by turrets consisting of pellets of soil that
ofall pereiopods and abdomen cream with whendryarelightgrayin color, contrasting
pinkish blush. Podomeres ofantennae and sharplywiththegreen tobrowngrass. Inan
antennules cream to pale tan; flagella pale account ofthe discovery ofthis crayfish by
VOLUME NUMBER
104, 2 315
Ken Steigman, Eig (1990) included a pho- ofthe proximal podomere ofthe uropod is
tograph ofthe Parkhill Prairie and another not always produced into a spine; it may
of what appears to be a female ofP. (G.) even be truncate. The most readily recog-
steigmani. nized variations occur in the number oftu-
Disposiitonoftypes.—Theholotypicmale, berclesontheseveralpodomeresoftheche-
form I, allotype, and morphotypic male, liped: the ventromesial surface of the
form II, are deposited in the National Mu- ischium has 2 or 3; 6 to 8 tubercles occur
USNM
seum ofNatural History, 220525, in the dorsal surface of the merus where
220526, and 220527, respectively, as are usually 2 are spiniform (rarely 1 or 3), the
theparatypesconsistingof1 51, 5 3II, and ventromesial row consists of 9 to 14 and
12$. the ventrolateral one of4 to 7; the number
Range andspecimens examined.—All of oftubercles in the arc on the ventromesial
the specimens available were obtained by surface ofthecarpusranges from to 4; the
K. Steigmanfromsnaketrapssetinthetype mesialmostrow oftubercles on the palm of
locality. Thus, all were crawling among the the chela consists of 6 to 8, 5 to 8 in the
grass when they wandered into the traps: 6 adjacent dorsolateral row, and 4 to 7 in the
$\, 5 6 II, and 12 2 were taken on 14 Feb more lateral curved row; the opposable
1990, 1 5 I on 28 Apr 1990, 2 3 I on 28 margin of the fixed finger exhibits 2 to 4
May 1990, and 15 1, date uncertain. In tuberclesproximal to the firstlarge tubercle
addition, the primary types were, among andacontinuingrowof4to6 moredistally;
other specimens, perhaps lured into a trap thecorrespondingmarginofthedactylbears
during a dry spell in late June or early July 3 or4inthebasalconcavityand4to 8 more
(when 5 to 8 cm cracks penetrated a meter distally, 1 to 3 tubercles are present on the
into the soil) by introducing into the trap proximomesial surface ofthe finger.
water-soaked foam rubber in an open zip- Relationships.—Procambarus (G.) steig-
lock bag. mani has its closest affinities with P. (G.)
Variations.—K\\ ofthe specimens that I regalisand, as suggestedintheintroductory
have examined are from the same locality, remarks, may well prove to be a subspecies
and the variations noted among them are ofthe latter which is currently known only
minor ones, many, ifnot most, associated from the Ouachita and Red river basins of
with injury in earlier instars. The rostrum southwestern Arkansas (Hobbs & Robison
reaches anteriorly between the proximal 1988:fig. 15). The similarities between the
ends ofthe penultimateandultimate podo- two include almost identical terminal ele-
meres of the antennular peduncle. Bran- ments of the first pleopods in the male,
chiostegal spines, which at most are small, thickened rostral margins, postorbital ridg-
maybevestigial orlacking. Tubercles along esthatareswollenposteriorly,chelipedsthat
the posterior flank of the cervical groove, aremarkedlysimilar, andcolorpatternsthat
one ofwhich a probable homologue ofthe also betray a close common ancestry. Fea-
cervical spine, may or may not be present; tures that seem most reliably to distinguish
the postorbital ridges may terminate ante- them are the following found in the new
riorlyinaminute, corneoustubercleormay species: anasymmetrical arrangementofthe
merge imperceptibly with the surface ofthe first pleopods, the firstrecorded fora mem-
orbital area; the ridges are sometimes so berofthe subgenus Girardiella; the absence
depressedjust posterior to midlength as to of tubercles on the ventral surface of the
appear almost bipartite. The paired scler- palm ofthe chela; the strongly tuberculate
otized knobs in the posterior gastric region annulus ventralis, and the cherry red and
are not always discernible. The mesial lobe pale blue coloration of the male and the
316 PROCEEDINGSOFTHEBIOLOGICALSOCIETYOFWASHINGTON
chocolate brown color noted in the female. tionconcerningthetypelocalityandthefew
Should these colors prove to be typical of habits ofthe crayfish reported here. Appre-
the species they will furnish a ready diag- ciation is also extended to J. F. Fitzpatrick,
nostic characterforrecognition ofthe cray- Jr., oftheUniversity ofSouthAlabama, H.
fish in the field. In P. (G.) regalis, the pleo- H. HobbsIIIofWittenbergUniversity, and
pods ofthe male are always symmetrically my colleague T. E. Bowman for their com-
situated; at least a few tubercles are always ments on a draft ofthis manuscript.
present on the ventral surface ofthe palm
ofthe chela, andin only one specimen [col- Literature Cited
N
lected 1.5 mi (2.4 km) ofParaloma, Se-
Eig, Jonathan. 1990. Mud boggling.—The Dallas
vier County, Arkansas] that I have exam- MorningNews,Saturday,July21,1990,pp. 1A,
ineddotheanterolateralprominencesofthe 5A.
annulusapproachthetuberculatecondition Hobbs,H.H.,Jr. 1990. Onthecrayfishes(Decapoda:
that appears to be typical ofP. (G.) steig- Cambaridae)oftheNechesRiverbasinofeast-
mani. The colors ofthe carapace ofP. {G.) em Texas with the descriptions ofthree new
regalis as recorded by Hobbs & Robison species.—Proceedingsofthe Biological Society
ofWashington 103:573-597.
(1988)arebrownishredandtannishcream, , & H. W. Robison. 1988. The crayfish sub-
not nearly so brightly colored as are the genus Girardiella (Decapoda: Cambaridae) in
males ofthe new species. Arkansas,withthedescriptionsoftwonewspe-
Etymology.—Itisapleasuretonamethis cies and a key to the members o—fthe gracilis
crayfish in honor of its discoverer, Ken gorfotuhpeoBfitohleoggiecnaulsSPorcoiectaywdoafrwW^a.shiPnrgotcoenedi1n0g1:s
Steigman. 391-413.
Reimer,R.D. 1975. Procambarus{Girardiella)curdi,
Acknowledgments anewcrawfishfromArkansas, Oklahoma, and
Texas (Decapoda, Astacidae).—Tulane Studies
Thanks are extended to K. Steigman of inZoologyandBotany 19(1 & 2):22-25.
the Heard Natural Science Museum and
Wildlife Sanctuary, McKinney, Texas, for DepartmentofInvertebrateZoology,Na-
providing me with the specimens on which tional Museum ofNatural History, Smith-
this description is based and for informa- sonianInstitution,Washington,D.C. 20560.