Table Of ContentPROC. BIOL. SOC. WASH.
107(2), 1994, pp. 325-339
AEGLA PEWENCHAE, A NEW SPECIES OF
CENTRAL CHILEAN FRESHWATER DECAPOD
(CRUSTACEA: ANOMURA: AEGLIDAE)
Carlos G. Jara
Abstract.—The description ofAeglapewenchae, a new species offreshwater
anomuran crab from the Rapel, Maule, Itata, Bio Bio, Imperial, and Tolten
riverbasins is given. Its diagnostic characters are: 1) rostrum longand narrow,
styliform, scarcely troughed both sides ofrostral carina; 2) anterolateral angles
of carapace spiniform, slightly divergent; 3) marginal scales of rostrum and
hepatic lobes minute; 4) orbital spine clearly defined, with a smaller second
one some distance below; 5) anterolateral angle offirst hepatic lobe spiniform;
6) branchial borders smooth; 7) palmar crest wide and thin, its border deeply
serrateormicrodenticulate; 8)chelipedswithdorsalsurfaceofpropodusdensely
covered by minute lens-like scales; 9) anterolateral angle ofsecond abdominal
epimeronspiniform.Aeglapewenchaeresembles, toacertainextent,A. rostrata
Jara, 1977, and ^. abtao Schmitt, 1942a.
ThezonebetweenAngosturadePaineand year period, while sampling the Andean or
Chilian, in central Chile, is one ofthe most upperriverstretchesandtheCoastalorlow-
ancient and densely populated zones be- erriver stretches, on both sides ofthe Chil-
causeofthefertilityofitssoils,mildclimate ean main longitudinal highway (Carretera
and abundance of streams and rivers that 5) which crosses most ofthe river systems
providewaterforagriculturalirrigation.Ae- along continental Chile.
gla has seldom been registered in these flu-
vial bodies. However, this seems to be re-
Aeglapewenchae, new species
lated more to the difficulties in identifying
the specimens collected than with low col- Figs. 1, 2, 3
lectionefforts(N.Bahamonde,pers.comm.). Type material.—Holotype: Instituto de
Bahamonde & Lopez (1963) reported the Zoologia, Universidad Austral de Chile,
presence of A. laevis talcahuano Schmitt, IZUA C-338, adult male collected in the
1942b, from seven localities between the Bio-Bio River, 16 km S ofLosAngeles, un-
Zamorano River (tributary of the Cacha- der bridge of Carretera 5 (37°35'45"S,
poal-Rapel River system) and the Nuble 72°16'30"W), ProvinceofBio-Blo, VIIIRe-
River in Chilian, as well as A. concepci- gion, Chile, 21 Feb 1983, by C. G. Jara.
onensis Schmitt, 1942a, from the Tronco Allotype: IZUA C-338, adult female.
River (Colchagua Province), and A. mau- Paratypes: IZUA C-338, 5 adult SS (PI to
lensisBahamonde &Lopez, 1963, from La- P5) and 3 adult 22 (P6 to P8). Same locahty
guna del Maule. and date as holotype.
This paperdescribes anew species ofAe- Diagnosis.—Carapace longer than wide;
gla, which was found almost continuously rostrum elongate, styliform; anterolateral
betweentheColchaguaProvinceinthenorth angles ofcarapace acute, slightly divergent;
and the Cautin Province in the south. The scales on rostral and hepatic borders very
specimens were collected during an eight- small; orbital spine well developed, dorsal
336 PROCEEDINGS OF THE BIOLOGICAL SOCIETY' OFWASHINGTON
to a second smaller one; anierolaieral angle apace, between anterolateral lobe and cer-
of first hepatic lobe spiniform: branchial \ical groove, almost straight. Hepatic lobes
borders smooth, noticeablyarcuate; palmar well delimited by shallow furrows; all of
crest laminar, expanded, its border micro- them with one acute apical scale. Remain-
denticulate to dentate; dorsum of prop- ing margin with irregular row- ofsmall, im-
odus of chelae densely covered by minute equal scales.
lens-like scales; anterolateral angle of sec- Dorsimi of postcer\"ical carapace mark-
ondabdominalepimeronsharph-acute, spi- edl\-andtmifomih- convex. Sutures (lineae)
niform. fine, shallow-. Cardiac area and areolawide;
—
Descriprion ofholoiype. Rostro-frontal areola slightly inflated, its dorsim:i leveled
end narrow, bound by sHghil>' inflated an- with gastric area. Border ofbranchial areas
terolateral lobes scarcely distinct from pro- smooth, narrowly marginated and slightly
togastric prominences. .Anterolateral lobe recurved, with irregtilar row of fine acu-
prolonged in conical acute spine, well sep- minate scales mingledwith short stiffsetae.
arated from orbital spine, its apex reaching Dorstini of abdominal tergae sUghtly
posterior border of cornea. Orbital spine punctate; small tufts offine shon setae pro-
small, slender, acute. recur\-ed towards an- trude from ptmctae; tufts thicker and more
terolateral angle; its length ^-j to ^4 lengthof numerous on flanks ofepimera. .Anterolat-
anterolateral spine. Frontal-width abouthalf eral angle ofsecond epimeron prolonged in
precervical width. Orbits \vide. compara- short, stout, conical spine, its apex over-
tiveh" shallow, their depth about halftheir reaching adjacent branchial border. Pleural
maximum -width. Extraorbital sinus -well angle of third and fourth epimera sharply
defined, wide, slightlyas>-mmetrical. Orbit- acute. Telson cordiform. medially articu-
al margins with four or five minute well late. Ventral surface offourth thoracic ster-
spaced scales. num flat, slighth- convex; its frontal border
Rostrum narrow, srxliform. its width at straight at center and slightly- concave near
level of posterior margin of orbits -/? its anterolateral angles abuttiag in short bltmt
length. Cross-section of proximal half cones.
rhombic; distal halfsubcircular. Apex end- Chehpedsrobust,leftlargest.Chelaestout,
ing in acute conical scale. Rostral margins o\-oidal. Left propodus markedl>- convex,
defined only on proximal half of rostrum. inflated overitsproximal -?; right subtrian-
Rostral carina low. narrow-, reaching mid- gular. Dorstmi of propodus with oblique.
pointofrostrumflankedbyshallow-troughs; blunt, low- ridge bervveen carpus-propodus
itsproximal end markedby pair oftinypits and propodus-dactAlus joints, and parallel
between protogastric lobes; its dorstun with to base ofpalmar crest. Palmar crest sub-
tw-Q rows ofminute scaleswhich merge into rectangtilar. slightly excavate, its border
one. distalh'. Carinais replacedby irregular clearly denticxilate. merging anteriorly into
row- ofwell spaced scales which increase in predacrxlar lobe. Right crest with ^ acute
size distall>-. on distal halfofrostrum. denticles, left with 6. becoming progres-
Dorsum of precervical area uniformh' si\elymorerecurvedtowardsproximal end
convex; no marginal plateau on dorsum of ofcrest: right crest ends proximally in ro-
hepatic lobes. Epigastric prominences bust denticle partially separated from pre-
scarceh' distingiushable. except by 1 or 2 cedingonesbydeep,widenotch. Postcrestal
nodules bearing 5 to 8 minute apical scales. sinus deep. wide. Dorstmi ofchelaecovered
Protogastric lobes less prominent, marked b\ tin>-. blunt, conical scales that become
b> 7 (left) and 5 (right) apical scales in ar- larger toward distal end ofboth propodus
quate row. Dorsum of carapace smooth, and dact>lus where they intermingle with
polished, slighth- punctate. Margins ofcar- bundles ofshon stiffsetae. Dacrvlarlobeas
VOLUME NUMBER
107, 2 327
A B
Fig. 1. Aeglapewenchae, newspecies. A, male holotype, dorsal view. B, female allotype.
low blunt tubercle with apical scale 2 or 3 (right) and 9 (left) cones; the five distalmost
times larger than those on surface ofprop- procumbent. Ventral borders smooth, end-
odus. Ventral surface of chelae slightly ingin acute conical spine; innerone slightly
punctate, convex, polished, without scales curved; external border, next to merus-car-
or setae except at propodus-dactylus joint. pus articular node, with distally directed
Dorsum of carpus globular, with field of smallacutecone. Ventralborderofischium
minute conical scales over lateroextemal slightly concave, with small tubercle
half Internal border with 3 robust acute crowned by conical scale and few stiff"short
conical spines that decrease in size proxi- setaeatbothends. Distodorsal angle ofme-
mally; apex ofsecond right spinebifid. Car- rus ofsecond and third pereiopods fringed
pallobe spiniform, separatedfrom adjacent by stiff" short setae mingled with conical
articular nodule by shallow furrow; sepa- scales; 1 or 2 are central and prominent.
rated from distalmost spine ofcarpal crest Dorsalborderofmerusofsecondpereiopod
by wide sinus. Ridge along dorsum ofcar- fringedbylongplumose setae; fringeabsent
pus well marked, made up by 9 coalescent, on third pereiopod. Distal third ofventral
little prominent, tubercles, each with 2 to 4 median line ofdactylus ofsecond to fourth
apical scales in oblique row. Lateroventral pereiopodswithrowof3 to 7 acicularscales
nodule of carpus-propodus joint with mi- decreasing in size proximally.
nute flattened conical scale and short setae. Description ofallotype.—Aside from the
Ventral face ofcarpus gently convex, with- relatively larger abdomen and smaller che-
out spine. Distodorsal vertex of merus of lae (secondary sexual characters), the allo-
chelipeds as spiniform tubercle crowned by type diff"ers from theholotypeinthe follow-
2 acute scales and some stiff" short setae. ingaspects: scalesondorsumofchelaelarger,
Dorsal border ofmerus sharp, with row of particularlyoverdistalhalfofpropodusand
spiniform cones decreasing in size proxi- dactylus; tubercles ondorsal midlineofcar-
mally; distalconetwice sizeofsubdistal; 10 pus prominent, some spiniform; ventral
328 PROCEEDINGSOFTHE BIOLOGICALSOCIETY OFWASHINGTON
^
mm
1.5
Fig. 2. Aegla pewenchae, new species, male holotype. A, precervical carapace in dorsal view; B, same in
lateral view; C, anterolateral angle ofsecond abdominal epimeron in lateral view; D, telson plate; E, fourth
thoracic sternum.
border ofmerus ofchelipeds with spine at chelaewith I (left) and 3 (right) scalesform-
limit between median and distal thirds of ing row; anterolateral angles offourth tho-
article; 2 similar spines at distal third of racic sternum flattened and little scalloped;
external lateroventral border of merus of external flank ofcarpus-propodus articular
right cheliped; predactylar lobe well de- node with spiniform tubercle; punctae on
fined, specially when seen from ventral face dorsum of carapace coarse, deep; extraor-
of chelae; midventral line of propodus of bital sinus comparatively narrow.
VOLUME 107, NUMBER 2 329
Fig. 3. Aeglapewenchae, new species, male holotype (continuation). F, left cheliped in dorsal view; G, left
chelaseenfromdactylustop; H, rightchelipedindorsalview; I, rightchelaseenfromdactylustop; K, same in
ventral view; L, ischium andmerus ofleftchelipedin ventralview.
Color.—In life, dorsum ofcarapace uni- ofchelae and dactyls ofpereiopods yellow-
formincolorvaryingamongspecimensfrom ish orange; intensity varying greatly among
light olive green to dark green; color more individuals. Scales amber-like, translucent,
intense in furrows and depressions of the mountedontopoftuberclesandspinesivo-
carapace, over the frontorostral area and ry white to light yellow changing progres-
proximodorsal area of chelae. Distal zone sively to general background color of car-
330 PROCEEDINGSOFTHE BIOLOGICALSOCIETY OFWASHINGTON
apace toward their bases. Ventral surface such a diverse combination of characters
white in recently molted individuals, and that it is difficult to advance a hypothesis
smokey tan in animals in pre-ecdysis. about its phyletic relationships.
Inalcohol-preservedspecimens,carapace Aegla pewenchae resembles A. rostrata,
creamy white varying from almost trans- from lakes in the Tolten and Valdivia river
lucent injust molted individuals to yellow- basins,inhaving: rostrumnarrow, elongate,
ish brown with dark brown spots in indi- scarcelytroughed;orbitsample;orbitalspine
viduals in pre-ecdysis. Superimposed on well defined, accompanied by second one
general background color, blueish tones in subordinate position; palmar crest wide,
minglewithothercolorsinvaryingintensity lightly built, its border dentate to micro-
and extension. Dorsum of chelae, gastric, denticulate; dorsum of chelae covered by
and cardiac areas, and dorsum ofsecond to fine scales; and, dorsum of carapace dark
fourth abdominal segments of P7 and P8 greencontrastingwithmarble-whiteventral
light grayish blue changing to ivory white surface. In the Imperial River basin, both
overbranchialareas; centerofposterobran- species coexist, being difficult to differen-
chial areas dark rose; same hue, but more tiate. A. pewenchae differs from A. rostrata
intense, stainsdactylusofpereiopods ofP7. in lackingdenticles on the branchial border
Etymology.—Thenamepewenchaeis the of the carapace, and in having the dorsal
latinizedgenitive feminine singularform of surface ofanterior branchial area convex.
"pewenche,"theaboriginalamerindiansin- Aegla pewenchae resembles A. abtao
habiting the upland plateau at the origin of Schmitt, 1942a, distributed between the
the Bio Bio River. Tolten River basin and the Chiloe Island,
Distribution.—Table 1 contains the basic in having: comparatively short, triangular,
data on records ofAegla deemed to be con- scarcely elongate rostrum; male chelae
specific with A. pewenchae. Noteworthy is markedly unequal in size, fingers short and
the distribution ofA. pewenchaewhich ap- robust; dorsum ofcarapace coarsely punc-
pearscloselyrelatedtotheAndeanandpre- tate; palmarcrestthickand narrow, its bor-
Andean stretches ofthedrainage systems of dernodulatetodentate; spinesoninnerbor-
Rapel, Maule, Itata, Bio Bio, and Imperial der ofcarpus and dorsal ridge ofmerus of
rivers. Figure 4 shows the geographic range chelae short, thick, and stout. Aegla pew-
of^. pewenchae. The species is found from enchae differs from A. abtao in lacking a
theChimbarongo River, inthedrainageba- denserowofconicalscalesalongrostralbor-
sinoftheRapelRiver,totheDonguilRiver, dersandthickprotuberantscalesonthesur-
tributaryoftheToltenRiverbasin.Thespe- face ofcarapace. For comparison with the
cies is distributedalong480 km ofthe Chil- holotype ofA. pewenchae. Fig. 5 shows the
ean territory. In the Bio Bio River basin A. frontal end andthe left chela ofa fullgrown
pewenchae is found along most ofthe 380 male ofA. abtao.
km ofmainstream, includinglakesGalletue Aeglapewenchaeis a phenotypically well
and Icalma, sources of the Bio Bio River. defined species, associated with the Andean
The absolute upper limit ofthe species al- piedmont zone of several Central Chilean
tituderange(II50 m)isfoundintheselakes, river systems. Towards the West its distri-
while the lower limit (ca. 100 m) is found butionextendstotheCentralValley, ingen-
at several points along the Chilean Central eral coinciding with the fluvial zone where
Valley. Inthe drainage system oftheTolten the mean current velocity allows forthe de-
River,A.pewenchaeisonlyfoundinasmall positionofgravelandsand. Thesegradually
basin that drains the north-central area of replace the boulders and coarse gravel that
the extra-Andean Valdivian territory. predominate in the upper part ofthe basins
Remarks. —Aegla pewenchae presents where A. pewenchae is commonly found.
VOLUME NUMBER
107, 2 331
Table 1.—Records ofA. pewenchae, new species, in addition to the type series. All samplesare depositedin
the Collection ofthe Instituto de Zoologia ofthe Universidad Austral de Chile (IZUA-C). R. stands forriver,
L. forlake, and J forjuveniles(specimensin which the gonoporesare not visible).
Specimens
Collection Latitude/ Dateof
number Locality longitude collection a s J
503 R. Chimbarongo 34°46'S, 71°08'W 12 Dec. 91 11 15 49
—
344-A R. Claro 35°11'S 71°24'W 14 Feb. 83 14 13
393-A R. Claro 35°25'S 7i°4rw 01 Aug. 87 3 2 —
492-B R. Lircay 35<'25'S 71°34'W 13 Dec. 91 19 21 2
347-A R. Maule 35°28'S 71°57'W 15 Feb. 83 23 2—5 2—4
342 R. Longavi 35°37'S 71°46'W 17 Feb. 83 2
493-A R. Putagan 35°46'S 71°40'W 13 Dec. 91 15 11 32
490 R. Ancoa 35°54'S 71°30'W 13 Dec. 91 29 22 6
395-A R. Liguay 35°57'S 7i°4rw 10 Nov. 85 — 4 —
— —
394-A R. Longavi 36°00'S 71°43'W 10 Nov. 85 2
489 R. Longavi 36''14'S 71°30'W 13 Dec. 91 6 4 33
491-A R. Cato 36°15'S 7r4rw 13 Dec. 91 6 7 4
—
396 R. CatC 36°17'S 71°40'W 03 Mar. 73 1 2
482 R. Nuble 36°29'S 71°45'W 07 Dec. 91 14 40 83
480 R. Bustamante 36°34'S 7r45'W 07 Dec. 91 2 4 —
479 R. Chilian 36°41'S 7r54'W 07 Dec. 91 8 16 6
478 R. Diguillin 36°54'S 72°05'W 07 Dec. 91 4 9 2
477 R. Danicalqui 37''02'S 72°01'W 07 Dec. 91 10 12 6
481 R. Cholgiian 37°irs 71°59'W 06 Dec. 91 16 6 7
470 R. Huepil 37°13'S 71°57'W 06 Dec. 91 16 14 9
— —
336 R. Bio Bio 37°17'S 72°43'W 19 Feb. 83 8
474 R. Laja 37°18'S 71°58'W 06 Dec. 91 20 15 43
520-B R. Cholguahue 37°29'S 72°13'W 10 Oct. 92 10 16 2
472-A R. Quilleco 37°30'S 71°59'W 06 Dec. 91 18 22 13
—
425 R. Bio Bio 37°33'S 72°35'W 26 Jun. 85 2 7
475 R. Duqueco 37°35'S 72°09'W 06 Dec. 91 19 23 28
427 R. Huequecura 37-4rs 71°46'W 09 Apr. 87 3 8 1
340 R. Mulchen 37°43'S 72°15"W 21 Feb. 83 1—3 10 —1
222-A R. Malleco 37°47'S 72°41'W 06 Jun. 81 4
—
335 R. Queuco 37°51'S 71°38'W 21 Feb. 83 1 14
—
339 R. Renaico 37°51'S 72023'W 21 Feb. 83 3 3
334 R. Malleco 37°58'S 72°26'W 22 Feb. 83 6 16 7
—
318 R. Traiguen 38°14'S 72°19'W 23 Dec. 82 9 18
323 R. Quino 38''18'S 72°25'W 23 Dec. 82 41 25 10
—
317-A R. Colpi 38°19'S 72°47'W 22 Dec. 82 5 4
324-D R. Quillen 38°24'S 72°47'W 22 Dec. 82 7 4 —
326-B R. Quillen 38°25'S 72°56'W 22 Dec. 82 3 10 7
266 R. Bio Bio 38°38'S 71°06'W 04 Feb. 69 6 5 12
—
186 L. Galletue 38°40'S 71°19'W 16 Feb. 77 6 11
319 R. Bio Bio 38°43'S 71°09'W 05 Mar. 83 45 31 22
—
426 R. Bio Bio 38°46'S 71°14'W 08 Apr. 87 16 2
187 L. Icalma 38°48'S 71°17'W 17 Feb. 77 11 10 _1
320-B R. Quepe 38°51'S 72°37'W 21 Dec. 82 6 3
327-C R. Donguil 39°06'S 72°4rW 21 Dec. 82 48 47 66
327-D R. Donguil 39''06'S 72°41'W 21 Dec. 82 63 54 46
332 PROCEEDINGSOFTHE BIOLOGICALSOCIETY OFWASHINGTON
Fig. 4. Geographical range ofA. pewenchae, new species. Stars indicate sampling localities; black dots,
geographical localities.
^
VOLUME NUMBER
107, 2 333
mm
5
i;-'; '•. ', y''^//^-'f•'\i.-^i''^•f:^*t-'-'-'.-^ ..'•;1
•''; Vy' '':'. ' '*ti^*V---;-;.'''-,•^''•v^;^;^-*-''!-.'
>.''> .'
Fig. 5. ^eg/a abtaoSchmitt, adult male. A, precervical carapace, dorsal view; B, leftcheliped, dorsal view.
334 PROCEEDINGSOFTHE BIOLOGICALSOCIETY OFWASHINGTON
Aegla abtao, which replaces A. pewenchae Morphological Variations
to the south ofthe Tolten River basin, also
prefers this biotope (see Jara 1980:93-96; The expression of the taxonomic char-
as A. riolimayana?). Both species share acters varies among type specimens. In PI
characters seemingly associated with living andP5 therostralapexoverreachescomeae
in moderate to fast running water environ- ca. two times theirlength, butin P6 and P7
ments, i.e., the smooth longer-than-wide itoverreachescomeaebylessthanoncetheir
oval carapace, the relatively short but nar- length. The orbital spine is comparatively
row acute rostrum, and the marked heter- small in the holotype and in P2, P7 and P8,
ochely ofadult males. However, this mor- its length being one fourth the length ofan-
phological similarity is not necessarily terolateral spine of carapace, but in PI
indicativeofcommonancestrybetween the equaling one halfthe length ofanterolateral
two, and may well be the result ofconver- spine. The first left hepatic lobe ofthe ho-
gence. lotype, PI, P7, and P8 ends in one acute
Aegla pewenchae, throughout its ample scale, but the right in two; the opposite oc-
geographical range, shows a relatively wide curs in P6. The curvature ofbranchial bor-
exophenotypicalvariationwhichmostlyaf- ders varies in relation to the relative width
fectstherostralandprecervicalmorphology ofcarapace; it is minimum in the holotype
and the maximum size of the specimens. andmaximuminPI Indentationofthepal-
.
However, this species does not show mor- mar crest is notorious in the holotype, but
phological variations related to the lacus- insignificantin PI, P2, P3 and P5. The pre-
trine environment. In A. rostrata, A. abtao dactylar lobe merges completely into the
(Jara 1986a), and^l. denticulata{]ava 1986a, palmar crest ofthe left chela ofPI, P2 and
1989),thelacustrineenvironmentdoesseem P3, but in P5 it does in both chelae. The
to induce an overspinulation or spination ventralfaceofcarpusofchelipedsissmooth
ofthe carapace edges. in all specimens except in PI and P3 (left
The latitudinal limits of A. pewenchae chela), and P5 (right chela), which have a
seem to coincide, more or less, with well spiniform tubercle. The inner ventral bor-
definedzoogeographical boundaries. In fact, der of merus of chelipeds is smooth, with
its present northern limit lies at the Cacha- one distal spine in all specimens except in
poal-Rapel River system, just to the south PI, P4, and P5, which havetwo, and in P8,
ofthe Maipo Riversystem where two other which has three.
freshwaterdecapod crustacean species reach Table 2 contains the morphometric data
their southern limit, namely, A. papudo ofthetypeseries. Measurementsweretaken
Schmitt, 1942b (unpubhshed data), and with a digital caliperto the nearest 0.1 mm.
Cryphiopscaementarius(Molina 1782)(Ba- Themorphometricparametershereconsid-
hamonde & Lopez 1963). A third species, ered were defined by Jara & Lopez (1981).
the burrowing crayfish Parastacus pugnax The morphological variations most com-
(Poeppig 1835), reaches its northern limit monly found among the specimens exam-
at the Aconcagua River (Bahamonde & ined, additionally to the type series (Table
Lopez 1963),just to the north ofthe Maipo 1),arerelatedwiththerostrumandthefron-
Riversystem. AttheTolten Riverbasin the tal area. Figure 6 shows the variation ex-
situation is less clearly defined. HereA. ab- tremes in 29 specimens from Malleco Riv-
tao reaches its northern limit, while P. pug- er. A negative correlation between length
nax, and the trichomycterid fish Bullockia andwidth ofrostrum, and alsobetween ros-
maldonadoi (Eigenmann 1927), reach their tral length andfrontal width appearsamong
southern limit (unpublished data). them. Figure 7 records the extreme varia-
