Six species of Pagurus, P. samielis (Stimpson, 1357),
P. hirsutiusculus (Dana, 1857), P. granosimands (Stimpson,
1859), P. hemphillii (Benedict, 1392), P. ochotensis (Benedict,
1851) ani P. beringanus (Benedict, 1392) occur ilong the
suores by the Hopkins Marine Station, Facific Grove, California.
The first four are found in the intertidil with more or
less overlap ing distributions. Although excellent keys
exist, notibly that of Schmitt (1921), for distinguishing
anong the adults, little information is availible on the
larvae and juveniles of thase species. Throuch the vork
of Thompson (1903), Hays (1939), and Goffin (1950), the
larvae and immature adults of P. samuelis can be identified;
However the larvae and juveniles of the other soocies ire
not recognizable on the basis of published accounts. For
the present work an ittempt has been made to determine means
for identifving the larvae of the first five aforementioned
species ind the voung adults of the first four.
Metnods
Collections were made througneut the intertiail region
t kopkins Marine Station to obt in gravid femiles ind
Imaiture adults of the first four species named. Cne gravid
famale of P. ochotensis was obtuined by diving at a depth
of about eight meters; no inmature idults were found.
samples were obtained of P. beringanus.
The gravid females were kept in two-liter flasks of
seaater in the laboratory until their larvae hatched. On
hatching, twenty-five of the most active larvie of aach
srecies were placed in each of two finger bowls and the
2.
water temperature maintained at approximately 13° C. Once
a day the water was changed, after which the lurrae were
fed Artemia nauplii.
Whenever possible, characteristics cnosen for larval
identification were those which could oe observed with a
dissecting microscope, although a compound microscope was
occasionally necessary. Gross morphology was found to be
similar for all species; for this reason the following key
emphasizes differences in pigmentation.
No characteristics of the glaucothoe were found to be
sufficiently prominent for rapid identification; therefore
a more detailed study was undertaken, examining the structure
of the telson, uropods, and pleopods under 400X magnification.
In all cases, the specimens were lignted from above
rather than from below because the pigmentation was not
always visible in transmitted light. Both living and
preserved larvae were studied, but, in order to prevent
errors from shrinkage and movement, all measurements were
made immediately after the larvae had been killed in
magnesium chloride, chloral hydrate, or a combination of
both. The larvae were measured dorsally from the most
anterior part of the head in the midline immediately below
the rostrum to the central notch on the posterior edge of
the telson. Measurements were tiken at each larval instir
available daring the study.
Time lid not permit raising the species pist metamorphosis.
For this reason the species characteristics of juveniles and
small adults were determined by starting with adult specimens
lirge enough to be clearly identified by Schmitt's key (1921)
and working down to progressivelv smaller individuals of
each species. For tnese animals, the wilth of the hard
carapice vas used is a measure of size, following Coffin
(1950), althouzh the curvature of the cartpace made such
measurement difficult. Eich specimen was ilso geasired
from the tip of the median tooth of the rostrim to the
tip of the V-shaped indentation on the posterior edge of
the carapace. Since this part of the key was degeloped
for ready use in the field, it also emphasizes coloratien
and patterning rather than minute merphological differences,
Examples of larval and post-largal charictenistics
were recorded with photographs and camera lucida dravings.
Results
General larval characteristics may be found in
Coffin (1060). Specific charicteristics of the larvie
ire shown in Tables I through VIII. In these taoles,
all areae on the bodv are colorless unless otherwise
noted. Two colored regions are similar in all five
species: a vellow area anterier to the heart and dorsal
to the stomach and a red oral region fading to orange
or vellow-orange in the viscera. The vellow pigmentation
noted on the proximal medial face of the maxillipes in the
First zooa o" P. hirsutiusculus is distinctive but mav eisily
be missed unless the lighting is carefilly adjusted. The
pi ment locks the same as that found in the yellow area
anterior to the heart and is visiple only when lighted
indirectly from above. This coloration was observed
occasionally in the second zoea, put rarely in a later stage.
while the table emphasizes pigmentition, certiin
morphological characteristics ire alse prominent enough
to be of value for rapid identification. Exam'nation of
the one available specimen of third zoea P. ochotensis
indicated that there may be more spines on the uropods
of this species tnan on those of the intertidal species.
Spines on the uropods of P. granosimanus ind P. hemchillii
re all approximately the same, while in P. samuelis and
P. hirsutiusculus the most proximal spine is much smaller
or is often missing, apparently as a result of breakage.
where high magnification (400X) is available, the
number of prominent spines on the exopodite of the second
antennu provides a definite morphological characteristic
helpful in partially separating the five species. The
eight antennal spines on P. ocnotensis are evenly
separited
seines
and readily distinguishable; however the most iist
of the other species are close together and usually are
not discernable except under higner magnification.
Glaucothoe stages of only P. hirsutiusculus ind
P. granosimanus were available for examination.
Extensive collection of the immature adults yielded
crabs of all the species except P. ocnotensis and
P. beringanis, ranging in size from those described in
Schmitt's key (1921) to tne following mininum crapace
widtus: P. samuelis-O.5mm, P. nirsutiusculis-O.6mn,
P. granosimanus-O.8mm, and P. hem hillii-1.1nw. By
cemparing overlapping characteristics, it was possiole
to assign inlividuals of even the smallest size to the
proper soecies. Their charactristics, as thev cainged
with increasing size, ire sown in Tables IX to XIII.
The smallest gravid females found had carapace vidths of
1.5mm for P. samuelis and 1.2 mm for P. hirsutiusculis.
The same color patterns exhipited by these females were
found in crabs ranging down to carapace widths of 1.2nm
for P. samuelis and 1.0 mm for P. nirsitiusculus. Egg-
bearing specimens of P. granosimands ind P. hemphillii
were not found in sufficient numbers for any minimum size
at sexual maturity to be determined.
One morphological feature of the post-larval inlividuals
worthy of mention is the shape of the rostrum. In linge
specimens of P. granosimanus, the median projection o" the
frent of the carapace is proadly rounded, short and very
blunt, in accordance with Schmitt's key (1921). In
specimens of P. grinosimanus hiving a carapace width of
about 2.5mm or less and in the other three species in ill
post-larval stages, the rostrum is rather sharply pointed.
Discussion
In both the larval and post-larval specimens, axamination
revealed jefinite similarities between P. samelis ind
P. hirsutiusculus and between P. granosimanus anl P. hemohillii.
In the larvae, P. ochotensis formed a third group. Individuals
could pe assigned relatively easily to one group or inother
by the use of pigmentation and morphology; however, it wis
frequently exceedingly difficult and oc asionally impossible
to determine the species of an inlividual vithin one of these
species pairs. The tables are so designed is to emplisize
these sigilarities.
Provenzano (1964) suggests that the number of mijor
telson proces es in the glaucothoe may be a good familial
202
6.
character, i.e. all the species of Paguridae for which data
hive been published bear eight such procestes.
Tor
P. granosimanus this was found to be valid.
However, of saven specimens of P. hirsutiusculus
studjed, only one was found to have eight setae. Five
of the other six specimens had six setie and one specimen
had only five. On the specimen with five setae, one of
the medial setae apparently had been lost; while there
was no visible trace of its point of attachment, there
was a gap in the pattern. On the specimens pearing six
setie, no trices were seen which suggested the loss of any
processes.
On the basis of the specimens examined, the normal
number of setae appears to be six; nowever, in light.
of the one exception studied and the previously published
data on Paguridae, it is probaple that the numbor of
telson setae or the glaucothoe of P. hirsutiusculus is
also eight.
In his study of P. samuelis, Coffin (1960) states that
the smallest sexually mature females ne found during
the summer months had a carapace width of 1.8 mm. wnereas
Je encountered a number of gravid females meisuring only
1.5 mm across.
Summary
The larvae and yoing idults of Pagurus samuelis
(Stimpson, 1357), Pagurus hirsutiusculus (Dana, 1857),
Pagurus granosimanus (Stimpson, 1859) and Pagurus
hemphillii (Benedict, 1851) were comparatively studied to
liscover characters by which these species could be readily
20
distinguished without the use of a high magnification
microscope. P. samuelis and P. hirsutiusculus, P
granosimanus and P. hemphillii, ind P. ochotensis could
easily be separated into the above groups but further
identification proved difficult in the young adults and
sogetimes impossible in the larvae. The following
dichotomous keys summarize the results.
KEY TO ZOEAL STAGES
A. ist antennae shorter than rostrum; 4 or 5 spines on
uropods of 3rd zoea and l spines on uropods of htn zoea;
8 spines on 2nd antennae; vellow "star" on sides of
carapace --- - - - - - -Pagurus ocnotensis
AA. Ist antennae approximately equal to rostrum in length;
3 spines on uropods of 3rd zoea, 3 or 4 on hth zoea; 5
or é spines on 2nd antennae; no vellow "star" on sides
of carapace
B. Red spot or general redlish nue on the lateral fices and
distal ends of the protopodites of the ist ind 2nd
maxillipeds; small red spot or no red spot on proximil
end of protopodites of 3rd maxillipeds; red on anterior
faces of eye stalks and on sides of curapace; 5 spines on
2nd antennae; 2 large and i small spine on uropods of
3rd and hth zoea; generally "V" shaped notch in telson
of ist zoea
C. No vellow on inside of proximal ends of ist and 2nd
maxillipeds; small red spot usually not appearing
until 3rd zoea - - - - - - Pagurus samielis
CC.Yellow on inside of proximal ends of ist ind 2nd
mixillipeds of ist and often 2nd zoea, rarely seen on
8.
3rd zoea (only visible when indirectly illuminated
from above); small red spot on 3rd maxilliped usually
appearing in 2nd zoea, more easily seen than on
P. samuelis - - - -
Pagurus hirsutiusculus
BB. Colorless to vellowisn tinge on protopodites of ist and
2nd maxillipeds or red spot or hue on posterior faces
of ist and 2nd maxillipeds; large red spet on proximal
end of protopodites of 3rd maxillipeds except in ist
zoea; no red on anterior faces ofeye stalks or on sides
of carapace; 6 spines on 2nd antennae; 3 large spines
on uropods of 3rd zoea, and 3 large and 1 small spine
on uropods of hth zoea; "V" shaped or shallow "U"
shaped notch in telson of ist zoea
D. Colorless to vellowish tinge on ist and 2nd maxillipeds;
no red spot or very faint red spot on 3rd maxillipeds
of ist zoea, large in later zoeal stages; generally a
shallow "U" shaped notch in telson of ist zoea-
- - - - - - - - Pagurus granosimanus
DD. Red spot or hue on posterior faces of protopodites of
ist and 2nd maxillipeds except in ist. zoea; red spot
on 3rd maxillipeds in all zoeal stages; generally a
"V" shaped notch in telson of ist zoea - - -
— - —
Pagurus hemphillii
KEY TO POST-LARVAL STAGES
A. Legs with dark and light bands on most segments or (if
carapace width w/» 2.5mm), uniformly dark with tubercles
of the same color except for longitudinal blue stripes
on dactyli. Carapace white with red edges or (if cw » 1.1mm)
yellow with brown streaks.
B. 2nd antennae redlish or (if cw) O.9mm) brown. Propolus
and carpus of chelipeds banded (to cw-2.5mm). Carpus
of walking legs of small individuals banded like other
segments. Legs finally (cw» 2.5mm) brown. - - -
- - - - - - - - Pagurus Samuelis
38. 2nd antennae colorless or green or (if cw »1.2mm) green
with white spots. Propodus and carpus of chelipeds
without distinct bands. Carpus of walking legs entirely
white (if cwc 1.Amm). Legs finally (cw) 3.3mm) green-
brown. - - - -
- - - Pagurus hirsutiusculus
AA.Legs darker proximally than distally or (if cw» 2.5mm)
uniformly dark with contrasting blue tubercles; no
blue stripes on dactyli. Carapace pinkish mottled yith
brown.
C. Legs white with pink merus or (if cw? 2.Omm) greenish-
brown; no white tips on claws or walking legs
(to cw-2.5mm). 2nd antennae of solid color. Eyes purple
and white. - - - - - - Pagurus granosimanus
CC. Less lemon-vellow (ischium and merus tending to brown)
or (if cw » 2.5mm) maroon with dactyli white distally.
2nd antennae brown with large vellow spots or
(if cw 73.1mm.) red with minute yellow spots. Eyes
black with vellow lines.
Pagurus hemphillii
207
LEGEND
TABLT I
PIGMENTATION OE THE MAYILLIPSD3--20SAL STAGES
P.s.-Piguris simjelis, P.h.-Pagurus hiraittuscilus, P.g.-Eiglris
ranasimanus, P.hp.-Pagiris nemphillii, 1.o.-Pagurus ocnotensis:
wxp.j-"irst maxilliped, mkp.2-second makilliped, mxp.3-tuird mixillipgi:
* Visible only when lighted indirectly from above
TABLE II
OTHER 20TAL PIGMENTATION
TABLT III
SHAPE CF NOTCH ON POSTERIOR EDGE OF ZOEAL
PELSON
TABLE IV
LENGTH OP 1st ANTEENAE--ZOEAL STAGES
TABLE V
NUMBER OT SPINES ON EXOPODITES O
2nd ANTENNAT--ZOEAL STAGES
TABLT VI
3PINES ON POSTERIOR BORDERS OF ZOEAL UROFODS
based upon one specimen
TABLT VII
SCTAE ON TTLSON 1D UROPODS OF GLAUCOTHOE
TABLE VIII
PLEOPOD SGTATION ON GLA ICOHOE
two specimens
TABLE IX
PIGMENTATION OF POST-LARVAL EYS
cirapace widt
TABLE X
PIGMENTATION OF POST-LARVAL 2nd ANTENNAE
TABLE XI
PTGMENTATION OF POST-LARVAL CA LIPEDS
Tible XII
PIGMENTATION OF POST-LARVAL CARAPACES IN DOR3AL VIE
TABLE XIII
PIGMENTATION OF POST-LARVAL AMBULATORY LEGS
GRAPH I
LENGTH 0 Z074
O
TABLE I
PIGMENTATTON OF THE MAXILLIPEDS--ZOEAL STAGES
2nd. Zoea
3rd. 2oea
th. Zoea
1st. Zoea
Red spot or general reddish hue on distal lateral facès
P.S
of protopodites ofmxp. and mxp.2
Colorless or with red spot on
mxp.3
Red spot or general reddish hue on distal lateral faces
P.h.
of protopodites ofp. and mxp.2
Vellow on medial proximal
ends of protopodites ofp.
Small red spot on proximal end of protopodite
and mxp. 2 **
of mxp.3
Colorless to vellowish tinge on protopodites of mxp.1 and mxp.2
P.g
Colorless or small red spot on Red spot on proximal end of
proximal end of protorodite
protopodite of mxp.3
of mxp.3
Small red spot or general rediish nie on posterior
P.hp
faces of orotopodites ofp.1 andp.2
Red spot on proximal ends of protopodites of mxp.3
P.o. Colorless to ellowish tinge on protopodites o xp.1 inxp.2
I P.s.-Pagurus samuelis, P.h.-Pagurus hirsutiusculus, P.g.-Pigurus
granosimanus, P.hp.- Pagurus hemphillii, P.o.-Paguris ochotensis,
Mxp.. first maxilliped, mxp.2-second maxilliped, mxp.3third
raxilliped.
*Visible only when lighted indirectly from above
TABLE II
OTHER ZOEAL PIGMENTATION
1st. Zoea
2nd. Zoea
3rd. Zoea
Ath. Zoea
Yellow spot on chelipeds
P.s
None
Red spot on
P.h.
chelipeds
Red on anterior faces of eve stalks and red spots, fading to
red-orange on the carapace
Yellow spot
1.5
lon chalined
None
P.hp
Yellos "star" on sides of cirapice-may be very difise
P.0.
Yellow spot on cheliped
TABLE III
SHAPE OF NOTCH ON POSTERIOR EDGE OF „ZOEAL TELSON
2nd. Zoea
3rd. Zoea
th. Zoea
1st. Zoea
Usaally "y" shaped
P.s.
Flattens and notch disappears
P.h
notch; may be flat
rU
shanad
Elattens ind notch lisappeirs
Shallow "y" shaped
suilly "V" shaped
Flattens and noten disap eirs
P.hp.
.. shaped noth
Tlattens and notcu disipper
207
P.S
P.h.
P.g.
P.hp.
P.o.
P.s.
P.h.
P.g.
P.hp.
P.9.
P.S
P.h.
P.8
P.hp
P.0.
P.h.
P.F
TABLE IV
LENGTH OF ist ANTENNAE--ZOZAL ST GES
Ist. Zoea
2nd. Zoea
3rd. Zoea 4th. Zoea
Ist. antennae extend to tip of rostrum
1st. antennae do not extend to
TABLE V
NUMBER OE SPINES ON EYOPODITES OF
2nd. ANTTINAE--Z0TAL STAGES
1st, Zoea
2nd. Zoea
3rd. 2oea
th. Zoea
5 spines in all zoeal stages
6 spines in all zoeal stages
8 spines in all zoeal stages
TABLE VI
SPINES ON POSTERIOR BORDEKS OF ZOEAL UROPODS
ist. Zoea 2nd. Zoea
3rd. Zoea
Hth. Zoea
Two long thick
spines; one short
and thinner,
ften broken
3 prominent
3 prominent spines.
spines
Ith: thin inl short
long thick
spines and 1
3 long spines
thin spine on
short spine
right side. On
left--3 thick,
1 thin
one specimen
TABLE VII
SETAE ON TELSON AND UROPODS OE GLAUCOT OE
telson--6 or 8 setae: (see discussion)
uropods--10 plumose setae on exopodites
telson--8 setae
uropods--12 plumose setae on exopodites
210
P.h.
P.5.
TABLE VIII
PLEOPOD SETATION ON GLAUCOTHOE
exopodite
endooodite
number of setae number of hooks
st pleopods
2nd pleopods
3rd pleopods
th pleopods
Specimen II
Specimen I
endopodite
exopodite endopodite
exopodite
setae
hooks
setae
hooks
st pleopods
2nd pleopods
3rd pleonods
8,9
hth pleopods
« two specimens
P.s.

P.0
P.hr
P.3.
F.h.
P.g.
P.hp.
P.h.
7.
P.hp.
TABLE IX
PIGMENTITION OT POST-ARAL TVES

3
17
Blick-bron with sotaal pa
Purble and wite strea
Dark red-orown
Black with distinct velloe lines
crapee width
TABLE X
PIGMENPATION OF POST-LARVAL 2nd ANTERAE

j
nm

Pink
Brown
to red
oolor-
Green witn white spot
Brown with vellow 3ot

everv 3-l segnents
less
everv 2-3 serments
Red-oringe to rad
Broun with vellot spot sverv hel witn munv ainite vl.
3-h segments
spets on nich segnent
TABLE (I
P
OF POST-LARVAL CRELIF S

17
3
Segments
red-bron
All segnents
roximally; brown
Mand
proximally,
Solid broyn, tabercl.
hite,
wuite
)and P
distally
colorless
listall
rand
Distal wite pand Uhifermly tin.
Lignt green¬
on M
wite, oter
small tubercles,
oron te wite
segments
o
white tips
distally
brown
n Cuaitefom
to tip
—
All secments brown itholue tuberele
Solibroyn
whit
lue-
hite
No white tips
sottedin
Lemr
Maroon griline Deep maraen itn oliisu tipercles
vello throige hrown rograssively farther distally
to lemon vellointil only verv tips remin walte
istall
merus, Ccrpus, Deictlus, rrpropors, r-pollex
P.3.
P.h.
F.K.
1.Hp.
P 5
P9
Phe
TASLE XII

IN
POST-LANVAL CAN PACES IN DOL VIEW

3nm
n

17
Wite to ello ith
Olive with white atrins
h
pededces
longitudtnal brawn stripes, brovn to purple spots
purple posteriorly
Wot'led green-brown with red apots anterierly,
oiert
vellow.
mrple apets posteriorly, lengitainl waite
vite
and vellow stripes
cent.
with red
spots.
es
rple
ae
nite
Grainv wnite,
te ith
Green anterior to grey posterior,
to sink,
ed-
brown and
speckled pink, brown,n wit
purple
aled
Pink mottled with brown
TASLE XIII
ATIO OP POST-LARVAL A3JLATOKY L2S
2m
3m
4mm
5mm
1m
Blue and brown striped
(oor-in
Dactylus
essnes
Solid brown tubercled, blue splotches
White, brown,
Propodus
Rd ly
white, ue to
distaly
distal end
elow
Brown prox
Carpus
distally
imallywhite
5olid brown, tubercled
Merus
distaly
Ischium
Longitudinal stripes of brown and increasingly
Colorless to
Dactylus
white,red to
darker blue
brown stripes
Indistinct redsripes
Propodus
tongitdina brown sripes
Prox
eteny towr
green-brown; distàl whte
red
ta end
dist
band
white
Green-brown with indistinct
Sold white Brown proximally to
Carpus
red stripes
completely
Brown
Brown'wth groimal white
Merus
Green-brown, lightly
proximally.
bands
white
tubercled
Tan to brown
Ischum
distaly
Uniform green-brown gradually reaching
Datyus
Solid white, tending
Propodus
tios; prominent blue tuberes
toward tan
Carpus
Brown with blue tubercles
Merus
Pink
Brown
Ischium
Deep maroon with blue tubercles
Dactylus
emon yellow
Propddus
lemon
extending progressively farther to
to white
Crpus
yellon
tip until only aistal half of dactylus
Grown
Merus
remains
white
Ischir
213
4.5
4.0
3.0
H
( 20
1.5
GRAPH I
LENGTH OF ZOEA
2 2
.
o
2222

222
8.
ofc

o
OT9
a da a add
ST ZOEA 2w.ZOEA 3R. ZOEA 4ru ZOA
P. samuelis

SlOmm

1O-2.4 mm

2.4 mm
White
Red-bre
P hirsutiusculus

08mm

0.8-1.2mm,


Od
2-38mm
. . ...


23.8mm
wn
81
P granosimanus
P hemphillii

Sllmm
Cl.2mm

I.1-2.5 mm

2-2.mm


2.5-3.4 mm







2lmm
234 mm



.....
* * . . . ...
..

EMaroon
Green-brownl Lemon
Literature Cited
Coffin, Harold G. 1960. The Ovulation, Enorvology and
Developmental Stages of tne Hermit Crib Liglris
muelis (Stimpson). Walla Walla College Publ. 25: 1-30.
Hays, kobert P., 1939. Notes on the Life History of the
Hermit Grab Pagurus samuelis. Mister of Arts Thesis,
Stanford University: 1-61.
Frovenzano, Anthonv J. Jr. and Anthony L. Rice, 1964. The
Larval Stages of Paguris marsni Benedict (Dacitola,
Anomura) Reared in the Laboratory. Crustaceana, 7:
18-235
Schmitt, Waldo L., 1921. The Marine Decapod Crusticea
California. Univ. Calif. Fubl. Zool. 23: 1-470.
Thompsen, Millet, 1903. The Metagorphoses of the Hermit
Crab. Proc. Boston 3oc. nut. Hist. 31: 147-200.