Full text - Acta Palaeontologica Polonica

Full text - Acta Palaeontologica Polonica

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ZO F I A K IELAN
ON THE TRILOBITE F AMILY ST A UROCEPHALIDA E
The ventral cep hali c s ut ures of t he ge n us Stauroc epha[us B ar r a n de,
1846, a re d escr ibed a n d a re s ho wn to be e u - p ty ch opari id type, t he ro s tra l p la t e
be ing extremely large . The origi n of thi s s truct ure in St au Tocep h a[u s is discussed.
T he si m ila rit ie s b e twee n St aurocep h a[u s an d O edi cy b e[e Wh itt in g ton , 1938, a re
poin ted 'o u t a n d th e two genera a re taken to constitu te a se pa ra te fa mily - the
Staurocep halida e. Staul"Ocepha[u s c/a v ij rons A nge lin , Sta urocepha[ u s s p , n, St auroce p h oh is so . b, St au Tocepha[u s s p . c, and O edicyb d e k ingi W h it t in g ton a re d escribed .
Abstra ct . -
INTRO DUCTION
In connec tion wi th a s tu dy of the Upper Ordovician tril obites of the
H ol y Cross Mountains (G6ry Swie tok r zysk ie) in Central Poland , the
present wri te r h ad an oppo rtuni ty to exa m ine the v ent r al cep halic
s u t u res of the ge n us S taurocephaius Barrande a n d the enti re ex os kele ton
of the gen us Oediqjb el e Whittington. As publication of th e monographi c
trea t ment of the whol e Upper Ordo vi cian trilo b ite faun a m e n ti on ed a bove
may take so me time, it is t hough t des irable to publish se pa r a te ly th e
resu lts bea r in g on the m orphol ogy a n d tax on om y of thes e ge ne ra .
The s p ec ies h ere des cribed are chiefl y f rom t h e Upper O r dovician beds
(zor..e of Stauro cephalus clavifrons), fr om th e loc aliti es of Brzezinki and
W6lka in the Hol y Cross Mts. The da ta con ce rni ng the s t ra ti gra phy of
these beds h ave bee n publ ish ed separately (Kiel an, 1956 ; comp, also
Kiel an, 1955) . The Staurocephalus clavifrons beds in the H ol y Cro ss Mts
cons is t of light-colou red mudstones a n d the s ta te of preserva ti on of th e
tril ob ites is mo stly good , tho ug h m a n y of the spe ci mens a r e com p ressed.
The trilobites a re u su ally pres erved as internal and ex terna l moulds, the
la tter s h owing as a r u le details of t he ornamentation, so that pl astic or
la t ex casts m a y be m ade from t hem in or der to s h ow t h e details of the
ex t e rn al surfac e of the t est. Some Sc andinavi an an d British speci mens of
S tauroc ephalus a n d Oedicyb el e h av e been ex a m ined f or comparison .
Th e te rminology of th e diffe r en t ty pes of ven tr al cep h a li c sutures us ed
in the p rese nt paper correspon ds to tha t of Rasetti (1952) a n d J aanusson
156
ZOFIA KI E L AN
(1956). Th e cond ition where the anterior bran ch es of the fa cial s u t u r e are
fused and no med ian s u ture is devel oped , is called t he levis ellid type,
that with a b roa d r ost ral pl a te t he eu -ptych opariid, and tha t w it h a narro w
rost ral pla te steno -ptyc hopariid. In the term inology of the la te ra l gla bellar lobes a n d furrows the present wri te r fo llows Jaan usson (1956): t he
furrows an d lo bes are nu m bered fro m bac k to front, th e lo bes b eing
lettered " L" (lo bus), the furrows .,S" (sulcus) .
Exa mination of m u ch of th e mat erial h ere descri bed has been ca rried
out du ring t he writer's stay at the P al eon tol ogical In s titu te of U ppsala
University in 1956 . P ro fes sor P. Thorsl un d h as provided the au tho r with
the facilit ies for stu dying at this Institu te. Dr V . J aa nusso n (Uppsal a
Un iversity) h as gi ve n th e a u th or continued assistance and m ad e m any
h elpful s ugges tions.
During the wri ter's stay in Br itai n Dr J . T. Templ e (Lon don University)
has offered very us eful criticism. The ac com pa nying pho tograp h s h av e
been taken b y Mr. Hjor th (P a leon tolo gical Inst itu te in Uppsa la) , Mr. J . M.
Br own (British Mu seum, Natural H is tor y in L on don) and Miss M. Czarnocka (P al eontol ogic al In s titu te in Warsa w)· The accompanying d r awin gs
h ave b een mad e by Mr . E. S tah l (Paleont. In s t. in Uppsala) an d Mr. A . Sulimski (Paleont. Ins t. in Warsaw) . To a ll these persons the writer wis hes
to express her gratitu de.
Th e writer is indebt ed to th e a u t hor iti es of the following Mus eu ms ,
which have provided h er with opportunities for examining the specimens
in their charge :
Museum of th e Geological Institu te (Instytut Geologiczny) in Warsaw
(IG),
Museum of th e P aleon tological In stitu te of Lund University (LM) ,
Mu seum of the P al eon tologica l Instit ute of Uppsala University (UM),
State Museu m of Natural H is tor y (Naturhistoriska Riksm useet) in
Stock ho lm (RM),
Mu seum of t he Geological Survey (Sver iges Geologisk a Uride rs kon ing)
in S tockholm (SGU) ,
Mu seu m of the P aleontological Instit u te, Un ivers ity of Co pe nhagen
(CM),
British Museum (Natura l H is tor y) in London (BM),
Sed gw ick Muse um in Camb r id ge (SM ),
Geologi cal Museu m of th e University of Oxford (OM),
, Paleontologica l Museu m of Oslo University (PMO),
Nat ion al Museum (Narodni Museum) in P r agu e (NM) .
T RILO BI TE F AM ILY S T AUROCEPHALIDAE
157
ON THE SYSTEMATIC POSITIO N O F STAUROCEPHALUS A ND OEDICYBELE
Th e systematic position of S taurocephalu s Barrande, 1846, h as be en
discussed by sever al au thors and it h as been placed in either the
Ch eiruridae (Raymond, 1913, placed it in th e subfamily Deiphoninae) , or
the Encrinuridae. Th e evide n ce for ex cluding Staurocephalus f r om th e
Ch eiruridae has been discuss ed by Reed (1898), King (1920), Warburg
(1925), Opik (1937) and P r antl & Pribyl (1947). The latter au th ors (1947)
have es tablis he d for Staurocephalus a n ew s ubfa mily, t he Stauroc ephalinae, within t he En crinurida e. Hupe (1953) has put the Staurocephalinae back in the Ch eiruridae, but without di scu ssing th e problem .
It should b e mentioned that King (1920) a ft er s tudy ing the hypostoma
of Staurocephalu s sta te d (p. 534): " It is difficult to find a ny family w ith
a similar type of h ypostome ; certain it is that it is far f rom the Ch eirurid
ty pe, but it must also be admitted that very little resemblance can be
s een ibetween it and th e normal en cr in u r id typ e, w ith its peculiar and
s triking cen tral tongue-like anterior protrusion. A s tu dy of th e hypostome
of Staurocephalus therefore confirms the view that it should be removed
from the Ch eiruridae, but does not seem to indicate that it should be pu t
in to the Encrinuridae..·"
The present writer ag r ees with Prantl an d Pribyl in excluding
Staurocephalus from the Cheiruridae, but at the same tim e s upp or ts the
opinion of K ing, that it should also be ex clu de d from the Encrinuridae.
In addition to the evidence of the hypostoma given by King, the structure
of th e pygidium and of the rostral plate of S taurocephalus is taken here as
a further support for excluding this genus from the Encrinuridae.
The members of the Encrinuridae can be recognized among th e other
Cheiruracea chiefly by their pygidial structure, characterised by a great
number of rhachial segme n ts an d comparatively fewer pl eural segments.
All the characters of the cephalon and thorax of the Encrinuridae as
defined by Schmidt (1881), Hupe (1953) an d others can b e r ecognized also
in some representatives of the Cheiruridae and Pliomeridae an d therefore
cann ot be claimed as par excellence encr inu rid. The pygidium of
Staurocephalus is quite different from that of the Encrinuridae : it is small,
with only 3 or 4 rhachial rings and wi th 3 pleurae produced into spines.
The rostral plate of encr inu rids is usually very narrow, of stenoptychopariid type (for ex a m ple Encrinurus and En crinuroides as figured
by Schmidt, 1881, pl . 14, . fig. 11-12, and Whittington, 1950, fi g. 2
respectively). The largest rostral plate of encrinurids described so far is
that of Atractopyge xipheres Opik (comp. Opik, 1937 , pl . 21, fig. 3) where
it is oblong (tr.) regular in shape and may be called eu-ptychopariid. In
Staurocephalus the rostral plate (see p. 166 and fig. 1 and 3) is extremely
158
Z OFI A K IEL AN
large a n d bro ad (l on g. and tr.) com posed of two p a r ts : an terior
(to pographically), bulbous a nd coarsely granulated, for mi ng the direct
con ti n uation of the bu lbous a nterio r gla be lla r lob e, an d po st erior, smaller,
m inu tel y g ranula te d, s ub-trapezoid in shape. Th is type of t he rost r al
p la te is quit e differ ent fr om any kn own so fa r in t he Encr inur ida e.
Of t he ge nus Oed icyb el e Wh ittington , 1938, on ly cra ni dia h av e so fa r
been kn ow n so that its systematic pos ition was ve ry uncerta in . A n
ex a m ina tion of- so me complete s pecimens of t h is genus f rom the Upp er
Ordovician of the H oly Cr oss Mts. and of S ca n ia has t hrown so me ne w
ligh t on th is question . T he si milarities bet ween Staurocep halus and
Oedicyb ele are striking (see fig . 2 and 5). In both of them gla be lla is
divi de d into a narrow poste r ior portion with three pa irs of late ral
gla bell a r furrows , and a n almost spherical anterior portio n consisting of
t he swollen fro nta l glabellar lob e, a lt ho ug h in S ta uroc epluitus t his lobe
is greater a n d mor e con vex th an in Oed icyb ele. The th orax a n d pygid ium
a re also very si m ilar. Ther e a re 10 thoracic segments in S taurocepha lu s
a n d 11 in Oedi cyb el e, bu t t he shape of thoracic pleurae p ro duced into long
spines - is closely comparable. Th e pygidia of the t wo gen era are a lso
sim ila r : t hey a re bot h s mall with 3 rhachial segments (3 to 4 in
Staurocephalus) and 3 pleurae produced into spines directed back w a r ds
a n d ending along a s traight tr ansverse line. In both cases the outer
su r fa ce of the ex oskeleton is st rongly granulated. Compa r ison of t he
ve ntral cep ha lic sutures is not possi ble as th e ventral p late of Oedicy bele
is not kn ow n so fa r.
It s ho uld be men ti oned t ha t Th orslund (1940) in describing th e
cr a nidiu m of t he new gen us l em t ella (regarded by t he p resen t author as
a j unior s ubjective synonym of Oedicy bele), re marke d (p. 161) on the
si mi la rities of the gla bella to t hat of Staurocephalus.
In view of simila rities be t ween Oedicy bele and Staurocepnaius the two
ge nera must be class ifie d together , bu t they cannot be refe r red to either
the Ch eiru r ida e or the E ncrinu ri da e, an d are h ere se parated into an
in de pe n dent fa mi ly , t he Stau rocephali dae.
DESCR IPT IONS
F am ily Staurocephalidae (Prantl & P ribyl , 1947)
Diag nosis. - F ac ial suture p ro pa r ian. Glab ell a divided into nar row,
parallel-si ded posterio r por tio n w ith 3 pai rs of lateral glabell a r furrows ,
an d a bulbous, spheri cal frontal lob e overhanging in front. (In Suiuroce phaIus ventral cephalic s u tures of eu- ptycho pa r iid ty pe, h ypost om a cons isting
TRILOBITE FAMILY STAUROCEPHALIDAE
159
of wings and tri angular, raised cen t ra l portion with two knobs) . Th orax of
10-11 segmen ts with pleurae produced into long sp in es. Pygidium small,
rhachis of 3-4 se gmen ts, pl eurae wi th 3 segments, produced into spines.
Entire body , es pe cially cephalon , strongly gra nula te d.
Occurrence. - Middle Ordovician (zon e of Nemagrap tus gracilis) Silurian (Lower Ludlow). Boh emia , Poland , S candinavia , Great Britain ,
Kazakhstan, North America, Australia.
Discussion. - Th e monotyp ic su bfam ily Staurocephalinae erecte d by
Prantl and P ribyl (1947) as a member of th e Encrinuridae, is here re ga rde d
as a sepa r ate fa mily . The family Stau rocephalidae is to in clude th e ge nera
Staurocephalus Barrande, 1846 a nd Oedi cyb el e Whittington, 1938;
.Temtella Th or slund, 1940, being r egarded as a junior s ubjective syno ny m
of Oedicyb el e.
Genus S tau rocep halu s Barrand e, 1846
Diagnosis. - Gl ab ell a with narrow, parall el-sided pos te r ior po r tio n an d
ex tremely bulbous , sphe r ica l fro nta l lo be, protruding over an d concealing
an te r ior margi n of cephalon . SI and S2 short an d circula r , S3 ex te n ding
ac ross enti re wi dt h (tr .) of gla be lla an d for m ing s ha r p poster ior boundary
of front al lobe . F r ee cheecks con vex, ge na l s pi nes pre se nt. Ros tral pl a te
la rge, lon g (sag.) divid ed into two pa rts : an teri or (topog raphi cally) , fo rmin g
the' direc t cont inuation of f ron ta l gla be ll a I' lob e an d posterior subtra pez oidal. H yp ostoma imperfe ctl y known , consisting of flatt ish ma r gin
wi th wings an d sha r ply ri sing blunt tri angul a r ra ise d cen tral po r tion with
tw o knobs behind cen tre.
Occurren ce. - Middle Ord ovi cian (zon e of Dicranograptu s clin gani ) Si lurian (Low er Ludlow) . Boh emia, P oland , Sc andinavia, Great Brit a in ,
Kazakhstan , No rth Am erica, Au strali a.
Discussion. - The typ e s pe cies of S taurocephalus is S . murchisoni
Bar rande, described b y t hat author (1846 an d 1852) f r om th e Silurian
(Wenlock) of Boh emia. An gel in (1878) has described Staurocephalus
clavifrons from the Uppe r Ordovician ("Stauro cephalus shales ") of
Vestergotland in Swed en . Th e la t ter s pec ies is red escribed in the presen t
paper. In addi tion to S. murchison i and S. clavifrons se veral species
id entified as Staurocephalus have been desc ribed from th e different parts
of the world, bu t it appea rs that se veral of the m do not in fact b elong to
the genus.
Among the spec ies r ecorded by Salter (1864 an d 1865) as
Staurocephalus, S . unicus Salte r h as been referred by Schmidt (1881) and
la ter by Reed (1906) to Sphaerocoryphe. Staurocephalus globiceps Portlock
a lt hough confirmed by Reed (1906, p . 152) as belonging to Staurocephalus
160
ZOFIA KIELAN
h as a diff erently shaped pygidium, a nd Begg (1940 , p. 298) s ugges ts t h a t:
" Th e affinities of this ge n us are wi th Sphaerocoryphe an d not with
Staurocephalu s" . Stauroc ephalus murch isoni Barrand e des cr ibed by Salte r
from the Wenlock Limeston e (1864, p. 1, pl. 5, fig . 1-4 ; 1865, p. 84, pl. 7,
fig . 13-18) is a ccor ding to Begg (1940 , P: 289) prob ably not cons pe cifi c with
Ba rrande's spe cies . Salter's original spe cimens exa m ined by the presen t
a u t hor, housed in the Brit ish Mus eum (Natu ra l History) an d in the
Geological Museum, Oxford Universi ty , a r e w ell preserved (comp. pl . I
an d II ). An ex am ina tion by the presen t writer of Barrande's type
s pecim ens in th e Nation al Museum in Prague h as led to the conclusion tha t
British sp ecimens are not con sp ecifi c with Cze ch s pe cimens.
British
spe cim ens differ from Czech in having coarser granulation and shorter
(long.) cephalon. In Stauro cephalus murchisoni th e posterior part of the
gla be ll a (lateral view) is situa ted much lower than the a n ter ior bulbous
part, whereas in British specimens (see pl. I, fig. 1 b, and pl . II , fig. 2 a)
the posterior part is only slightly lower than the anterior one. Therefore,
British Wenlock specimens of Staurocephalus, evi de n tly belonging to
a new species, are here provisionall y called Staurocephalus d . murchisoni
Barrande.
An examination by th e p resen t w r ite r of some of the Upper Ordovician
spe cim en s from Rhiwlas , Bala, N. Wal es , housed in the Sedgwick Museum
in Cambridge, figured by McCoy (1854, pl. 1 F , fig . 15, 15a) a n d by Salter
(1864 , pl. 5, fig. 5; 1865 , pl. 7, fi g. 19-20) as Staurocephalus murchisoni,
indica tes that they are conspecific with S . cZavifrons Angelin.
S taurocephalus near S . murchisoni Barrande, des cri be d from Australia
by Ratte (1888, p. 100, pl . 2, fig. 5-9) and later b y Etheridge and Mitchell
(1917 , p. 495 , pl. 27, fig. 6-11 and 13) does not s eem to be conspecific with
S . murchisoni Barrande.
S taurocephalus murchi son i Barrande (one cranidium) h as - be en
recorded also by Weber (1951, p. 39, pl. 5, fig. 10) from th e Silurian of
Kazakhstan.
Staurocephalus clarkei de Koninck (1898 , p. 36, pl . 1 fig. 13, 13a)
from the Silurian of Australia does no t belong to this g enus.
Staurocephalus clarkei Weller (1907, p. 207, pl . 24, fig. 15) from the
Niagaran Limestone of the Chicago Area, is known from one cephalon
only. The figure given by Weller doe s not show the details of its structure,
but shows that it belongs to Staurocephalus.
Weber (1948) has de scribed several poorly preserved cranidia of
Staurocephalus sp. from Kazakhstan (Mamontovo) , from beds evidently
corresponding to a part of Ashgill ian.
Some imperfectly known st aurocephalid species from the Middle and
Upper Ordovician beds of Norway and Sweden are described in th e
TRILOBITE FAMILY STAU R OC E P H AL I D AE
161
p r es en t paper as Staurocephalus s p. a, Staurocephalus ' sp. band
Staurocephalus s p. c.
The 'oldest known staurocephalid species is so far Stauro cephalus sp . a,
.from the Middl e Ordovician beds, Dicranograptus clingani zon e from
Norway (see p. 167). In th e lowermost part of the Upper Ordovician in
Dalarna, Sweden, on e specimen has be en found and is described h ere as
Staurocephalus sp. b. In th e Red Tretaspis mudstones of V estergotlan d
(Sweden), wh ich correspond presumably to the zon e of Dicellograptus
complanatus, some r a re staurocephalid specimens have b een found by th e
p resen t writer an d a re described here as Staurocephalu s s p. c. In th e
middle part of the Ashgill ian - zon e of Stauro cephalu s clavifrons,
r ega r ded usu ally as an eq u iva len t of th e Dicellograptus unc ep s zon e.
St aurocephalus is widel y spread ov er Eu rope, occurring in G reat Britain,
Sweden, Bornholm, Poland an d Kazakhstan. In the Silurian (Wenlock)
bed s sta uro cepha lid spe cies have been r ecorded f ro m Bohemi a, . Gr eat
Britain, Kazakhstan, North America a nd Au str alia.
As there are almost no data on the Middle Ordov ician sta urocephalids
(one poorly preserved cr anidium h as been found so fa r) - no r easonable
con clusions concern ing th e phylogen y of t h is genus ca n be drawn . It is ,
however , wo r th to mention th a t th e oldest known S tau roce phalus, vi z.
S tauroce phalu s sp. a diff ers from all the other s ta urocepha li ds to a very
grea t ex te n t. Th e Upper Ordovician an d Silurian s pec ies of Staurocephalu s
are similar in gen eral cephalic pattern a nd differ onl y in proport ions , bu t
it is not the cas e with Staurocephalu s sp. a. The cranidiurn of Stauroc ephaius sp . a (s ee fig. 4 a n d pl . IV, fig. 3) is much less convex than th ose
of all the other sta ur ocephali ds . The fro nta l lobe of t h e gla bell a is less
bulbous, and n ot un iforml y el ev ated , th e greatest ele va tio n b eing on t he
an ter ior part. Th e cheeks form con e-like ele va tions , situa te d fa r from t h e
frontal glabellar lobe. The cephalic s urfa ce is h ere mu ch less g ra nula ted
an d the la teral glab ellar pits a t S3 sh ow qu it e a differen t pattern. In S .
murchisoni and S. clavifrons the lateral pits on S 3 are la rge, de ep and
r ound. In Stauroceptuilus s p. a on the same place th ere a re 4 sm all shallow
pits, situa ted clos e to ea ch other (see fig . 4). The pair of pits at S 3 has been
described by Opik (1937, fig . 36) in Cybel ella grenwingki (Schmidt). Op ik
has interpreted th ese closel y s itu a te d pits , lying in on e fu rrow, as
corresponding to th e muscular attachment of th e mandibl e (Md) an d
a n ten nae (All), while th e an te r iorl y s it ua te d, compa rativel y large pits a t
dorsal furrows (anterior pits) as corresponding to antennuale (AI)' When
comparing the four sm all pits in Stauro cephalus s p. a with t he large pi ts
on the same place in S. clavifrons or S. murchisoni, ~t appears possible to
homologize them It see ms more r easonable to refe r the fou r small p its
to four s ma ll bran ch es of one mu scl e, corresponding to one cephalic
Acta P al a eon t ol ogl ca P ol o n ica -
vol , II/ 2- 3
11
Z O F I A KIELAN
162
app en dage , than to treat them as muscula r apodemes of different cephalic
appendages. The muscle divided into four branches in Staurocephalus
s p. a is in the other staurocephalids developed as on e singl e, s t r ong muscle
with a large apodeme.
Among all the above m en tioned staurocep halid species the ventral
s ide of the cephalon is known onl y in S. clavifrons from, Poland (se e p . 166,
f ig 3) and in S. cr . murchisoni from the Wenlodk Limestone of Malvern
an d Dudley , Grea t Britain (see fig . 1; pI. I and pl. II). The British
s pecim ens have been figured by Salter (1864 , pl. 5, fig . 1-4 ; 1865 , pI. 7,
R.P. _
-;--'-"""
F ig. 1. - StullTOc ephallls cf. m u r ch iso ni Ba r r ande ce p ha lon in a n te r o- la te ra l v iew, s lig h tl y d iagrarnmatical ; R .P. r os t r a l p la te, R r os tra l s u t ure, F fa ci a l sutu r e, C connectiv e s ut ure (O .M .- C.306); X 5.
f ig. 13-17) bu t the course of t h e ven t ral cephalic s u tures h as not b een
in di ca te d on these fi gures . An ex am ina ti on of Salter's ty pe s pe cimens , as
well as other conspecific s peci mens housed in the British Museum
(N atu r al History) h as shown tha t the gen eral shape of th e rostral pl ate
a n d t he cou rse of ventral cephalic s utu re s is sim ila r to those of
S· clavifron s. In S . clav ifrons the r os t ral su tu re runs (comp. fi g. 3) across
the bulbous part of cephal on , quite close to the cephalic margin on the
ve n t rally ov erturned part of t he cephalon, whereas in Staurocephalus d .
murchisoni it runs close to the cephalic margin but mo re dorsally. On
a ccou n t of th is the convex po rtion of the rostral plate in S. d . murchison i
is s till larger (long.) than in S. clavifrons. The connectiv e su tures run in
S . d . murchison i more obliquel y than in S. cla vifrons, there fore the
p osteri or p art of the rostral pl ate is in S . d . murchisoni n a r ro w er (tr.) th an
in S. clavifrons. There ar e 4-5 marginal spines on the r ostral pl ate
of S. d . murch isoni, whereas 6-7 in S. clavifrons.
A stu dy of the v entral ce ph ali c s utures of S . clav ifron s an d S. d .
murchisoni p ermits on e to visualize th e course of the v entral cephalic
su tu r es in their probable a n ces tors. In t h e ancestra l form the denticulated
TRILOBITE FAM I L Y S T AU R O CE P H AL I D AE
163
margin of th e cephalon probably form ed the real cephalic outline, the
frontal glabellar lobe being much less bulbous, the rostral plate smaller
an d the rostral suture running parallel or sub-parallel to the outline. On
ac coun t of th e enor mous increase in si ze of the f ron ta l glabe lla r lobe, th e
denticulated ceph ali c margin has moved ventrally under the bulbous lobe.
The rostral suture has had to migrate a cr oss the ventrally overturned part
of the bulbous lobe, towards its margin, since otherwise it could no t
function during ecdysis. The rostral plate thus formed is composed of two
different parts: the original rostral plate topographically posterior and the
an ter ior part formerly of the glabella .
There is one no me ncla t ural q uestion connected with th is p roblem. As
usually defined the glabe ll a form s part of th e cranidium ; as the latter
is limited by the faci al an d rostral s u tu res, the rostral plate can neither
belong to th e cran idiu m , nor consequently to the glabella. On the other
hand, the gla be lla may be de fin ed as the convex, central portion of the
cephalon, delimited in front b y the p r eglabella r furrow, which se ems to
be more reasonable. But in Staurocephalus th e preglabellar furrow run s
across the rostra l plate, topogr aph ica lly in fron t of the denticulated
margin, dividing the rostral plate into two p arts. If one acc epts the latter
defin iti on, th e a n te r ior part of the rostral plate would belong to the
gla bell a, but not the posterior part. This may give rise to some
misu nde rs tan din gs. Th erefore in the pres en t pap er the first definition
is a ccepted. T he convex middle part of the cephalon, formerly the
gla bella, is secon dar ily divid ed by the r ost ra l s u ture in to the gla bella
and t he r ostral pla te.
S taurocephalus ctavifrons Angelin , 1878
(text- f ig. 2, 3; p I. III, fi g. 2, 3; pl . IV , fig . 1, 2)
Bar-r ande ; F. McCoy , D escr ip t io n of th e B ritish
Pa le ozoic foss ils ..., p . 153, pI. 1 F , fig . Hi, 15a '.
Stauroceph a !u s M UTch i son i Barr a n de; J. W . S alte r , B r itish orga nic re main s,
Dec. 11, Tril. , p . I-p ar tim , p l , 5,fig. 5.
StauTocepha!us M UTch i son i Barr ande ; J.W. Sa lt er, A monog r a p h of British
tri lobites . p . 85-partim , p l. 7, fig . 19- 20.
Stau TO cep ha!ns cl av i fT on s n . sp .; N . P . A ng elin , P a la e on t ol ogia S cand inavica ,
p. 67, p l. 24, fig . 8.
StauTocepha! u s clav i fron s Angelin: E. O li n, O m d e Ch asmopsk a lk en och
T r in uc leusskiffern ..., p , 48, pl . 1, fig . 15-17.
Staurocepha! n s clavifron s An geli n ; Z . K ie la n, On th e stra tig ra p h y of the
U pper Ord ov ician ..., p l. 3, fi g. 3- 4.
1854. StauTocepha !u s M UTchi soni
1864.
1865.
1873.
1906.
1956.
Diagnosis. - Frontal lobe proj ecting for less than half its length
beyond ch eek margin. Dorsal furrows on the posterior part of glabella
ZOFIA KIELAN
164
s ligh tly converging ante r iorly. Ch eek s very convex, as hi gh as fron t al
glab ella r lobe. In lateral view of the cephalon posterior part of glabella
entirel y concealed b y 'c h eeks; 13-14 derrticles on fre e cheek , 3 on fixed
cheek , 6-7 on rostral pl a te. The whole exos keleton st rongly gra nu la ted .
F ig . 2. -
St au roc ep l!a l us
clavifrons
An ge li n
recon -
str uction ; X 8.
P ygidium with 4 rhachial rings , th e fourth rhachial r in g is comparativ el y large, shaped as triangular sh ield with two pits.
Mat erial. - Abou t 130 mo re or less fragm entary s pec ime ns, a few of
wh ich a re complete, from Brzezin k i an d W6lka in the Holy Cros s Mts. ,
TRI LOBITE FAM ILY STAUR OCE P H AL I D AE
165
zon e of Suiuroceptuilus clav ifr on s. Sev eral cranid ia an d pygi dia from
t he Stauroc ephaius beds of Scania a n d Ves te rgotland (Sw ed en) .
M easu rements of two s pec ime ns f rom Brzezinki (in mm):
2
Le ng t h of the e n tir e in div idual
Lengt h of th e cep halon
W idth of t he cep ha lon
Length of th e fronta l lobe
Leng th of the pygidi um (w ith spi nes)
W id th of t he pygid ium
3.9
1.6
17.2
7.5
2.7
1.0
0.55
0.7
4.5
3.0
3 .8
Description . - The ou tl ine of the cephalon is semicircular, inva ded
by th e front al lobe, whi ch proj ects for less than ha lf its len gth beyond
the ch eek margin. Th e fronta l lobe is s phe ri ca l a n d ve ry strong ly ,
u n ifor mly convex, its length b eing more than h alf th at of t he cephalon.
T he dorsal furro ws a re broad an d very deep ; on the pos terior pa r t of
gla be lla th ey r u n s ub- paralle l, sligt hly converging anterio rly. In the
an te r ior pa r t of the gla be lla th ey curve ro und the f ron tal lo be to th e
cep halic margin . Th e posterio r pa rt of t he glabe lla is convex (tr ). The
occipita l ri ng is conve x (sag.) an d in the middle part twice as br oad
(sag. ) as at the dorsal furro ws , wit h a sha r ply pointed occ ipital n ode.
The occi pital furrow is b road an d compa r ati ve ly s ha llow in the mi ddle
p a r t, with very deep, r ou nd pits at th e do rsa l furrows. There are t hre e
la te ra l glabella r fu rrows : 5 1 an d 5 2 for m la rg e, deep pits at t he dorsal
fu rro ws; 5 " ex te n ds across the ent ire wi dt h of gla be lla a nd is ve ry bro ad
a n d deep , w ith deep , la rge, round pits at th e dorsal furrows in the
cor ne rs. Th e ch eek is ver y strongly convex, more elevate d than th e
p osteri or portion of th e gla be lla . At th e hi gh est po int of the cheek the re
is a hi gh cy li n dr ica l eye, s urrou n de d by a shallow f u rrow. The vi su al
s u r face occup ies the grea ter part of the eye lob e, an d cons ists of abo ut
si xty sma ll h ex agon al fa cets. In la teral vi ew the cepha lon consists of
t w o eq ual circles (frontal lob e an d ch eek), the latter wi th t he eye at its
hi ghest poin t. La ter al border is broad , com pa ratively fl at , w ith 14
marginal spi n es on the free ch eek and 3 on the fixe d cheek. La teraJ
bo rder furrow is broad and distinct . Posterior border is convex , na rrow
a t the dorsal fu rrow an d becoming flatt er peripherally. The ge na l angl e
is produced in to a s hort
po st ero-l at erally directed s pi ne . Posterio r
I
bra n ch of th e faci al s u ture cuts t he cephalic m argin a s ho rt distan ce in
fr on t of the genal ang le an d runs an te r o- me diall y through the lateral
border, then t ransversely t h ro ug h the ch eek to the eye, roun d wh ich it
cur ves . The an te r ior border of the faci al suture r uns from the eye almostdi re ctly for wa r d to t he cephali c m argin, quite clos e to th e dors al furrow .
166
ZOFIA KIEL AN
Th e ventral cephalic s utu r es are of eu-p ty cho pa r iid ty pe . Th e rostral
su tu r e runs as a direct continuation of th e facial suture across the
bulbous part of the cephalon on its ventral side close to th e border of th e
cephalon, a nd divides th e bulbous part of th e cephalon into frontal lob e
and ro stral plate. The connectiv e s u tu res run obliquel y inwards acr oss
the doublure and curve in a slig h t curve outward, before reaching the
distal margin (comp . fig. 3), so that th e minimum width (tr .) of the
rostral pla te is topograf icall y an te r ior to its di st al margin. Rostral plate
R
-.
R
RP~
s __ \
A
B
Fig. 3. - St auroc epluilu.s clavifrons Angel in - r econ s tru ction of th e cep ha lo n;
A d orsal v iew (brok en lines ind icate the su tures a nd cephalic m argin, a n d the
black spo ts (S ) - th e m argin al s pi ne s, both on t he ventral side of the ce p h a lon),
B outline of t he p r ofil e, R r ostral s u tu re, C con ne ctive su t ure, R.P. ros tral
plate , S spi ne; X 8.
is very large, wide (sag .), cons is ti ng of two parts: a n a n te r ior and
a posterior, divided by a transverse furrow . Th e topographically
anterior .p a r t of th e rostral plate is a direct continuation of the frontal
lobe, on the lower part of th e anterior bulbous portion of the cephalon,
and forms a convex, gra nula te d semicircle. On the posterior border of
thi s part of the rostral plate th ere is a sha llow, transverse fu r r ow, and
posteriorly to ita transverse row of 6-7 short spines, forming a direct
continuation of a row of spines on th e cheek margin. The posterior part
of the rostral plate is sub-trapezoidal, minutely granulated and much
s mall er than the anterior portion. One incompletely preserved specimen
of a hypostoma shows its triangular shape, similar to that figured by
Salter (1865, pl. 7, fig . 17). But on account of the bad state of preservation
of this hypostoma details of its str uct ur e cannot b e observed.
TRILOBITE F AM I L Y S T AU R OC E P HAL I D AE
167
The thorax is composed of 10 segme n ts . Th e rh ach is: is convex (tr .)
ta pe r in g gently to th e posterior segmen t. Ratio of rhachial width (t r .)
to that of pl eura with spine is 1:1.25. Pl eurae ar e horizontal for th e 1/2 of
its length, th en curve a t sha r p a ng le backwards, a nd run po st ero-laterall y
ex ten ding into spines. On th e inne r (horizontal) part of t he pleura th ere
is a shallow furrow (tr .) dividin g th e pleura into a n a rrow (long.) fl a t
an teri or portio n an d a str ongly conv ex , much broader posterior on e.
Spines of the last thoracic segments are directed entirel y backwards .
Pygidium. Ra tio of p ygidi al leng th (w ith spines) to width is 1:1.2.
Dorsal furrows a re v ery shall ow. The r hachis consists of 4 rings , the
3 anterior forming annulations , th e 4th a triangular pl ate with two large
p its in on e transverse line. Th e 3 pl eurae correspond to 3 anterio r
rhachial r in gs . Th e first pleura is wide (long .), directed tr ansversely and
divided b y a narrow pleural furrow in to a triangula r anter ior po rtion
an d more convex, wi der (long .) posterior p ortion . Second and th ird
pl eurae widen peripherall y and are convex ; 3 pairs of pleural spines
a re directed en tire ly backwards, those of th e first pair a re th e longest,
so that th e en ds of all three pairs are situated alon g one t ransverse
line.
. Orna m en tation . Small and large, s ha rp ly po inted tubercles cov er the
w hol e cephalic surface, except th e rhachial furrows. The posterior
portion of th e rostral plate and the marginal spines of the cephalon a re
minutely granulated . On th e rhachial rings of thorax, there are two
tr ansverse, irregular rows of tu bercles . Three irregular transverse rows
of tu bercles are on th e thoracic pleurae. Diff er en t sized tubercles a re
sca tter ed on the thoracic spines an d th e whole pygidial su rface.
Staurocephalus s p. a
(text-fig. 4; p l. IV , fi g. 3)
Material. - On e cr anidium from the Middle Ordovician (Upper
Chasmops L imeston e = 4b1\ of th e Norwegian division , cor re sp on ding
to the zon e of Dicran ograptu s cLingani, from Terneholmen, Askar, Oslo
region) . Th e sp ecimen was found by Dr . V. Jaanusso n (Uppsala
University) whilst examining th e rock for ostra cods.
Measurements (in mm) :
Length of the cran id iu m
Length of the fro n tal lobe
Wid th of t he f ron ta l lobe
Width of the crani d iu m
2.5
1.45
1.4
3.6
Description . - The dorsal furrows are broad and comparatively
shallow , running parallel to each .other bet ween the occipital r ing and
168
ZOF I A KIELAN
the thi rd lateral gla be lla r f u rrow (5 3) ' The posterior portion of th e
gla be lla is narrow an d convex (tr.), occi p ita l ring being broad and
im pe rfectly pres erved . Occipi tal furr ow is n arrow an d shall ow in the
middle part, s ligh tly convex an teriorl y, with r ou n d, deep pits a t dorsal
f ur r ows. Th e fi rs t a n d se con d lateral glabell ar fu rrows (5 , a nd 5 2) form
ro un d, s ha llow p its at dorsa l fu r ro ws . 5 , is a littl e larger tha n 5 2; 5 " is
ve ry w ide (sag .) a nd sha llo w, ex te n di ng ac ross the enti re w idt h of th e
gla bella . On t he posterior 'bor der of 5 3' at the dor sal fur r ow s, the re are
on each s ide t wo ver y sha llo w, w ell defin ed , s ma ll ro un d pits ca lled
F ig . 4. - S uiuroceptui lu s sp . a - St> S ~ a n d S;l th e f irst ,
sec o n d a n d th ir d latera l g labe lla r f urro w s; t h e third
com p use d o f 4 s m a ll p it s (P I -P~) (P .M .O .-67044) ; X 24.
h ere P, an d P2 (comp. fig . 4). Th ey are s ma ller than 5 , and 52' situated
very clos el y to eac h ot he r . Ex ternal pi t P2 is s itu ated more anteriorly
than t he in te rnal P" Two similar sha ll ow pits (Pa and p~) althoug h b adly
p reserved are situated on the a n terior border of 5 ", more peripherall y
t han P, a n d P2; P ~ (ext ernal) is situated mo r e poste r ior ly t ha n p". Frontal
lob e of gla bella is w ell defined, sp he ri cal, with greatest elevation in its
anterior par t. Posterior bord e r is narrow (ex sag .), convex, direct ed
outwa r ds at dorsal furro ws , bending at 1/ 2 of its length (tr .), dir ected
outwa r ds a nd ba ckwards , and produced in to the genal s p ine. Posterior
bo rder f urro w is very narrow an d thread-like. Ch eeks a re com parative ly
flat at t he dorsal f urrows a nd are set off distally in t h e fo r m of con e-like
eleva tions , with t he eye on its highest po int. This ele va te d portion of the
che c k is sit uated far from the frontal glab ellar lo be, and delimited fr om
it by the w ide, con ca ve an te rior p ortion of the f ixed cheek. F a cial suture
T R I L O B I T E F AM I L Y STAUR OC EP H AL I DAE
169
cuts the anterior cepha li c border close to the dorsal f u r ro w , r u ns
ba ckwards and inwa r ds, then bends in a sha rp cu rve an d r uns backwa rd s
an d outwards , cuttin g th e lateral bo rd e r a short distance in front of t he
gena l angle .
Ornamentation. - F r ontal lobe of glabe lla is minu tel y gran ulated .
The ch eek s h ave small sca tte re d tu bercles. P oste r ior po rt ion of t he
glabe lla is smooth with two sma ll sca r cely v isible t ubercles al on g its
mi d-li ne , t he posterior on L , an d anterior on L ~ . (For dis cu ssi on see p. 161).
Stau roce ptuilus sp. b
(pI. III, fi g. 1 a -c)
Ma teria i. - One cep halon fro m th e beds 1 m below the Red Tr etaspis
m u dstone, of Sk alberget, Dal a rn a, S weden ; the specime n h as been fou nd
by Dr . V. J aanusson an d ki n dly placed b y hi m at th e author's disposal.
M easu rem en ts (in mm):
Length o f the cepha lon
Length of the frontal lobe
Width of th e fronta l lobe
5.3
3.0
3.5
Descrip tio n. - Th e ou tli ne of the cep ha lon is half ell ipt ic, the length
to w idt h ra tio of the cep hal on bei ng 1:1.2. The b ulbous fr on tal gla bella r
lobe p r ojects for one third its len gth beyond the cheek m argin . Th e
fron ta l lob e is s pherical an d very st ro ng ly, uniformly convex, it s len gth
bei ng m or e t ha n h alf tha t of the cephalon . T h e occ ip ita l ri ng is w ide
([ on g.), n arro w in g at the dorsal fu rrows an d con vex nang . an d tr.). Th e
dorsal furrow is com paratively sha llow an d becom es deeper at t he dor sal
furr ows . The do rsal furrows are deep; on the pos terior part of the
gla bella they run sub-parallel, slig htly converging an te r iorly ; in th e
an terio r pa r t of the gla bella t hey cu rv e ro u n d the f ro nta l lob e to the
ceph alic m argin. 51 an d 5 2 a re scarcely visible (due in part to t he state
of pr es erv ati on) , S" ex te n ds a cross th e en ti re width of th e gla be lla and
is deep an d w ide. Th e ch eeks are con vex , s it uated low er t ha n the frontal
gla be ll ar lobe. In th e lat er al vi ew th e posterior por tion of the gla bella is
visible. Th e pos te rior border is na rrow an d convex . Th e la teral borde r
is com pa ra ti ve ly w id e a nd fl a t, w it h 14 m argin al spines on th e fre e
cheek an d t hree on the fixed ch eek. Th e genal angle is produc ed into an
incom ple te ly preserved spine. The course of th e facia l s utu res ca nnot be
observe d with any cer ta inty.
The wh ole cephalic surface ex cept the fu r r ows is cove red by s ma ller
and larger rounded tu be rc le s.
170
ZOFIA KIELAN
Discussion. - The spe cimen here described differs fro m Stau roce phalus clavifr on s in having t he narrower ce phalon, the larger fr on tal
gla be llar lobe, t he w id er (tr .) occipital ri ng , and mo re closely si t uated
t u bercles. In 5 . clavifrons th e tubercles are s harply pointed, whereas
h ere they are rather rounded , b u t this may be due to the state of
preservation. Th e di ff er en ce in the devel op m en t of the lateral glabellar
f urrows may b e also caused by the stat e of pres erva t ion .
Stauro ceptuilus sp. c
p I. I V , fig. 4, 5)
Material. - One incompletely preserved cra nidiu m and one pygidi um
f rom Red T r etasp is be ds of Skogastorp and Skultorp in Vestergotland,
Sweden.
M easur emen ts (in mm):
Length of the cra n id iu m
Length of th e fr on tal lobe
Length of the py gidium
W id th of the py gidium
2.0
1.0
1.7
1.5
Description. - The dorsa l furrows are broad and run pa rallel to each
ot her b et w een t he occi pital ri rig an d t he thi r d lateral gla b ell ar furro w '
(5 ,,). The posterior portion of t he gla be lla is convex, the oc cip it al ring is
broad (sag. ) an d convex (sag .) w it h an occipital no de; 5, and 5 2 fo rm
s m all, sha ll ow pits , 5 3 is very de ep , b road (sag.) and exten ds ac r oss t he
w ho le wi dth of the gla be lla, fo r ming a ve ry sharp posterior boundary of
the fr ontal lobe. The fro ntal lob e is convex a n d ro un d. T he ch eeks a re
m od era tel y convex, much lower than the fr on tal l obe, bu t higher than
t he poster ior p or tion of t he gla bella, which in the lateral v iew is not
v isi ble. Th e whole surface of the cranidiu m is u n iformly gra nu la te d
with s mall tu be rcles an d mi nute p its among them .
P ygid ium is inc om pletely preserved. The r hachis seems to be rather
narrow (tr .) an d long (sag .). The s pines w hich are well preserved, are
narrow (tr.), di r ect ed backw ar ds and gently ben t inwards.
Genus Oedicyb ele Wh itti ngton, 1938
S ynon ym: Jemt ella Thorslund, 1940.
Diagn osis. - Eyes small, fr ee cheek n ar r ow . (Ven t r al cephali c
s utures in comp le te ly k nown, h yp ostoma unknown). Gl ab ella divided
into par allel-s id ed p osterior portion with th ree p airs of late ral gla b ell ar
f u rrows, an d a bulbous fron ta l lobe, overhan ging in f ro nt. A pair of
obli que furrows on p osterior part of frontal l obe. Tho r ax of 11 segme nts
TRILO BITE FAMILY STAURO C E P H ALI DAE
171
with pleurae produced into spines. P ygid ium small with 3 r hach ial rings
a nd 3 pleurae produced into posteriorly directed s pines . Cephalon with
sever al strong tubercles , th e r est of exoskeleton granulated .
Occurren ce. - Middle Ordovician (zon e of Nemagraptus gracilis) Upper Ordovician (zon e of Staurocephalus clavifr ons). Central Poland,
Bornholm, Sweden , Grea t Britain.
Type species. - Oedicybele kingi Whittington, 1938.
Discussion. - Thorslund (1940) de scribed a n ew mono typic ge n us
J emtella from th e Middle Ordovician, zon e of Nemagraptus gracilis,
J emtland, Sweden. In discussing th e systematic position of Jemt ella ,
Thorslund sta ted (p. 161): " In many fe atures (viz. outline, ge nera l shape
an d furrows of gl abella), J emtella clava seems to agree with Oedicybele
idn gi Whitting ton (1938, p. 446, pl. XXXVIII, fig. 4, 5)" . It diffe re d from
th e latter species (according to Thorslund) in laoking a pr egIabellar field
an d an eye ridge. An exam ina tion of British, Polish and Scandinavian
specimens of Oedicyb el e kingi, including th e typ e specimens , has shown
that contrary to Whittington's statement there is no preglabellar field
in this species and thus the differences between Oedicybele and J em tella
a re fairly small and cannot be regarded as of generic rank. J emtelia is
th erefor e r egarded as a junior subje ctive synon ym of Oedicybele.
Oedicyb ele kingi Whittington, 1938
(tex t-fig. 5 ; p l. V a nd VI )
1938. Oed icyb el e k ingi n . sp .; H . B . Whittin gton , The geology of the d istric t aro und
Llansantffra id ..., p . 446, p l. 38, fi g. 4- 5.
.
Diagnosis. - Eyes small, tubercular, similar in shape and size to
other tubercles on cheeks surface. Transverse, indistinct eye- r idge
between eye and glabella. Po sterior portion of glabella comparatively
broad, frontal lobe sharply differentiated.
Occurrence. - Upper Ordovician, zone of Staurocephalu s clavifrons.
Central Poland, Bornholm, Scania, Vestergotland, Great Britain.
Material. - Whittington's original specimens, one nearly complete
specimen from R6stanga , Scania; one cephalon from Bornholm; two
cephala from Vesterg6tland; several nearly complete specimens, for the
most part deformed, from Brzezinki in the Holy Cross Mountains,
Measurements of on e specimen from Brzezinki (in mm) :
Length of the e n tir e in divi d ua l
Length of the cephalon
Length of the pygidium
Width of the p ygidium
13.0
5.0
2.0
2.8
172
ZOFIA KIELAN
D escr i pt i on . The outline of the cephalon is s u b-se micir cu lar,
sligh tly wider than a semicircle. Dorsal furrows are de ep, sub-parallel
on the posterior portion of glabella, and strongl y widening in front,
a rou n d the bulbous frontal lobe. The greatest width of the glabella is
more than twice that at the base. The occipital ring is narrow (sag). and
conve x. Occipital furrow is very s h all ow in the middle part, so th a t th e
j un ction between th e occipital ring a nd glabella is difficult to di stinguish
here. At the dorsal furrows th e occipital ring becomes n arrower and
deepe r. There ar e three distinct, shor t (tr.), deep , lat eral glabellar furrows;
5 , is transverse at the dorsal fu rrows, cro ss es less than 1/4 of the
gla bell ar width and th en bends sharply backwards and reaches the
occipita l furrow as a narrow, faint , very shallow furrow . The small b asal
lobes (L ,) thus cut off are very conve x . 52 and 5 " a r e short, de ep an d
dire cte d postero-mediall y. Th e bulbous frontal glabellar lobe is very
large , st rongly convex, slightly ove r h anging in fron t an d mu ch longer
th an th e posterior portion of the gl ab ell a. In its posterior part there is
a pair of very faint , short (long .) oblique furrows , parallel to th e dorsal
fu r r ows a n d vi sible only on well pr es erved specimens . Ch eeks are large,
triangular an d strongly convex. The posterior border is very convex an d
com pa ra tive ly n arrow a t the dorsal furrow, becoming broad er (long.)
a n d less convex peripherally , where it j oins the la te ral border. P osterior
border f ur r ow is de ep a t dorsal fu rrow and shallower distally. Lateral
border is convex and broader than the pos terior border. Lateral border
fu r r ow is sha ll ow and wid e. Th e ge na l a ng le is produced in to the ge nal
sp in e - whi ch is more than a th ird of the cephalic length, directed
postero-lat erall y and gently con ve x outwards. The facia l su tu re cuts the
la ter al border obliq ue ly in fr ont of th e genal angle, r uns a long th e lateral
border furrow, then bends inwards and runs an tero-medially to th e
sm all pustule-like ey e. Ante rior branch of the fa cial s utu re runs forward
to th e lateral border furrow a n d is then concealed under the overhanged
Iron tal lobe. The cou rse ofthe ventral cephalic s u t u re s in unknown . The
eye is v ery sm all , tubercular, sim ila r in size a n d sha pe to th e other
tu be rcles on the cheek su rfa ce and is connected with the gla be lla b y
the indistinct, transversely directed eye-ridge. On a ccount of the state
of preservation of th e eye, no tra ces of lenses are se en. Free cheeks a re
very small, comprising the lateral border and a very small part of the
cheek inside the lateral bord~r furrow . Hypostorn a is unknown.
The thorax is composed of 11 segments. Rhachial rings are strongly
conve x (long. and tr .) curving slightly forwards at th e dorsal furrows ,
an d forming there small lobes, which are slightly separated from the
r est of the rhachial ring. Pleurae are moderately convex, transverse at the
dorsal furrows a nd divided by a transverse furrow into narrow (long.)
TRILOBITE F AM I LY ST AU R O CE P H AL IDA E
173
an ter ior part, and a bro ad er , more con vex , posterior part. Both parts are
peripherally bent backwa rds , and produced into narrow post ero-laterall y
directed long spines.
Th e pygidium is v er y s ma ll, w ide r t ha n lon g. The w idth of th e rhachis
is less than a th ird of th e pygidial width. Rhachis tapers strongl y
~
Pyg.
F ig. 5. -
O edicyb el e lcin gi Wh itt in gton - r eco nstruc tio n (slig htly d iagra m ma tica l); X 8.
pos teriorl y, a nd is divided by two transverse furrow s into three r in gs,
th e last of which is very sma ll an d indistinc t. There are three
com pa ra tive ly fl at pl eurae, correspon ding to th ree r ha ch ia l r ings. They
a re produced in to wide (tr.) poste r iorly directed spines. The first pl eu ra
174
ZOFIA KIELAN
is the widest, with a ple ura l furrow dividing it into ante rior and
posterior portions but this furrow does not continue onto the spine.
Dis cus sion. - In the Upper Ordovician beds, zone of Staurocepha lu s
clavifrons of Central Poland an d Sweden, there are several fairly well
preserved specimens of Oedicybele. After an examination of Whittington's
type sp ecimens of Oedicyb el e kingi from Geological Dept. Birmingham
University, the present author has regarded the Polish and Scandinavian
s pecimens as conspecific with t he latter s pecie s. F rom Oedicybele
clara (Thorslund) of which only th e cranidia are kn own , O. k in gi differs
in having very s ma ll, t ube r cu la r eyes. In O. clav a t he visual lobes are
unknown , but there a re quite distin ct , elon ga te d palpe b ral lobes, which
in dica te d the pres en ce of ey es , rather larger than in O. kingi. Further
differ ences are in propo rtions of t he glabella , whi ch in O. kingi ha s
a comparatively 'broader posterior portion than in O. clava, while in the
latter species L 3 is m ore s t r ong ly differen tia ted a nd th e ge na l s pi nes a re
lo nger.
Pal eozooloc i cai Lab orat or y
oj t h e Po Lish A cademy oj Scien ces
Warszaw a, March 1957
RE FERENCES
AN GE L IN N . P . 1878. P al ae ontol ogia S candina v ic a . I : Cru stace a f'or rna tion is
Iransitionis, ed, 2. by G. Lindstrom, 1-96. L ip si a e (L undae) ,
BARRAND E J . 1846. No tice p r c lf m in a ir e sur Ie sys te rne e t le s tri lobites de Boheme,
1- 97. Leipzig.
1852. Sys te rne si luri e n du centre de la Boheme I : Reche r ches p alconto logtques.
1, 1- 935. Pra gu e.
1872 . Systeme si lu rien du ce n tre d e la Boheme . I : Rec h e r ch es p alcontolog i q ues. S u ppl. a u v ol. 1, 1-647. P r a gu e .
B EGG J . L . 1940. A n ote on the genera S ta urocep h alus a n d Sphae r ocoryp he with
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London.
ETHER ID GE R. & MITCHEL L J . 1917. Th e S ilu r ia n tr ilob ites of Ne w So ut h W a les'
w it h r eferences to t hose of ot h er pa r ts of A ustra lia. IV : The Calyrnen id ae,
Ch eiruridae, H a r pe idae, Bron te id ae e tc., w ith ap pe n d ix . P r oc. Linn. Soc.
N. S. Wal es, 42, 3, 480- 510. Sy dney .
H A WLE 1. & CORDA A. J . 1847. Prodrom e in e r M on ogr a p h ic der bo h misc hcn
T r il obit en. 1-176. Prag .
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44- 246. P a r is.
JAA NUSSON V. 1956. On th e tr ilobite ge n us Ce lm u s An ge lin , 1854. B ull. Ge o!.
I n st. Up p sa la, 36, 5, 35-49. Uppsala .
KIE L AN Z . 1955. 0 n owym try lobicie z r od za ju Ccra urus i znac ze n iu kolc6w
glowowyc h w on togen ezie i ff loge nez ie trylobit6w (A new tr ilo bi te of t he
ge n us Cera urus and the s ig ni fica n ce of ce p h a lic spines in t he on togeny and
p hy log e ny of tri lob ites). Acta . Geo!. P o!., 5, 2, 215-240. Consp , 63- 80. w a rsz aw a .
TRILOBITE FAMILY STAUROCEPHALIDAE
175
1956 . S tra tygraf ia gorne go or dow ik u w Gora ch S w ie tokr zy skich (On the
st r a tig r ap h y of the Upper Ord ov ici an in the H oly Cross Mts.). I bi d em , 6,
3, 254 -271 , Consp. 55 -64.
KING W. B . R. 1920 . N otes on t he gen us S ph aerocory,p h e. GeoL Ma g., 57, 532 -5 34.
London.
KONINCK L. G. de. 1898. D escrip t ion of t he P a leozoic fossil s o f New S ou th W a les
(Austra lia). Mem. G eoL Surv . N. S. W a l es, P al eon t. , 6, 1-298, S yd n e y .
Mc COY F . 1854 . Des cription of the B r it ish P a leozoic fos s ils in the Ge olog ical
Museum of the U n iv e rs i ty of C a m bridge. Cambro U n i v. P r ess, 1-66 1.
Cambrid ge .
OLIN E . 1906 . Om de Ch asmopskal k en oc h T r inucleusskiff e rn Mots v ar a n de
bildn in gare i Skane, M edd. L un ds G eol. F iiUkl., B , 1, 1-79. L und .
OPIK A. 1937. ' TrHobiten a us E s tland. Acta e t Co m m en t . U n i v . Ta r tu ensi:>" !S 2~
3, 1-163. T a rtu.
PRANTL F . & PRIBYL A. 1947. Cla ssifi ca tion of some B oh e m ian Cheiruridae
(Trilob itae). Sborn. N ar , Mus. v Praze, 3 B , 1, 1-44. Prah a .
1948. Some n ew or im perfe ctl y known Ordovici a n trilobites f r om Bohemia .
Bull. Int . Acad. tch eque Sci ., 49, 8, 1- 21. Praha .
R ASETTI F . 1952 . Ven tral cephalic su tures in Ca mb ri an tr ilob it es. A m er . J . Sci. ,
250, 885-898 . New H aven.
R ATTE F . 1888 . N ot e on s om e tr ilo bites ne w to Austr a lia . P r oc. Li nn. Soc. N . S.
W al es, 2 (1887 ), 95-102. S ydn ey .
R A YMOND P . E. 1913. T ril ob it ae. I n : East ma n R. & Zit te l K. , T ex t-b ook of P ale on tol og y . London.
R EE D F . R. C. 1898. N ote on the a ffi n ities of th e gene ra of t he Cheir urid ae. G eoL
Ma g., 4, 5. London .
1903-1906. T he L owe r P a leozoic T r il obites of th e G ir v an d is tr ict , Ayrs h ir e .
Pa la eon togr. s oc., 1-186. Lo nd on .
1928. N ote s on t he fa m ily E nc r inu r id ae. Ge ol. M ag., 45, 51- 76. Londo n .
SA LT ER J . W. 1864. F igures a nd description s ill u strativ e of Br itish organ ic
r e m a in s. XI: Tril ob it es. M em. GeoL Su r v . U n. K in gdom , 1- 3. Lon d on.
- - 1865. A Mon ograph of B r itish T r ilobit es. P1. II. Pa l eon t ogr. Soc., 1- 224
Lond on .
SCHMIDT FR. 1881. Revision de r os tbaltisc he n sil u r ischen T r ilobiten . I : P ha copi den, Cheirurid en und E ncr inurid e n . M em . A cad. I m p . S ci., S er. 'i , 30, I ,
1-2 38. S 1. P e te r sbou r g,
THORS L UND P. 1940. On the Ch asmops ser ie s of J emtla nd a nd S ode r man la n d
(T varen) . Sv eriges geo l. under s.. C, 436, 1-191. Stockh olm.
WARBURG E. 1925. The Tril ob it es of t h e L epta e n a Li mes to n e in D al a rn e. B ul l
G eol, I n st. U ppsala, 17, 1-447. Uppsal a.
WEBER B. N . 1948. Trilobity s il ur skic h ot loze ni j SSSR. I : N izn esil ursk ie t r ilobitv .
Mo» ogr. P a l eon t . SSSR, 69, 1-11 3. Moskva-Leningrad .
1951. Ve r schnes ilursk ie trilobity SSSR. Tr . V sesoj. G eol. I n st ., 1-54. Mo skv a .
WE L LE R S. 1907 . The P al e on tol ogy of the N iagaran L im es t on e in t h e Chica go
Area. B ull. N at. Hist . Surv . Acad. Sci ., 4, 2, 163-281. Chica go.
WHITTINGTON H. B. 1938. The Geolo gy of the di s tr ic t a r oun d Ll ansan tffr aid
Ym Mechain , Montgomery sh ire. Qu art . J. GeoL Soc., 94, 423 -4 57. L ondon .
1950. S ix tee n Ord ov ic ia n genotype tril obites . J . P al eon t ., 24, 5, 531 - 565.
Menash a.
Z O F I A KIELAN
176
ZO F I A KIELAN
o
RODZINIE TRYLOBITOW STAUROCEPHALIDAE
Streszczen i e
S tan ow isk o sys te m atycz ne rodzaj u S taurocephalus Barrand e, 1846,
lokro tnie dy skutowane i r od za j ten byl za licz a ny
ba dz d o E ncrinu r-ida e. Dow ody
przema wra jace
bylo
wie-
badz do r od ziny Cheirurid ae .
za
wy d zie leniem
te go
r odzaju
z Ch e iruirid ae byl y omawiane m . in. p rzez Reed a (1898), Kinga (1920), W arburg
(1 9~5 ),
Opika (1937) oraz Pra ntla i P riby la (1947), przy czy m ci osta tn i a u t orzy
.
'
utworzy li dl a ni ego p od rod zine St a u r oce phal in ae w obrebie Encr inuridae .
Nal ez y podkresl ic, ze K in g (1920), na
.
po dstawie s tu di ow n ad
budo wa hyp o -
stom u stau r oce fal usa, wypowiec!zial pogla d, ze trud no jest zna le zc rod zine
d obne j b udowie h yp ost omu.
H y pos tom s ta urocefa lusa
jest odlegl y
0
zarowno
p ood
typu che i r uri dowego, ja k i c nkrinuri dowego . Bud owa h yp ostom u s ta u r ocefa lusa
potwier dza, zda nie m K inga , poglad . ze rodzaj te n powin ien bye w ydziel ony
z Chei r uridae. lecz, z
E ncr inur ida e .
dr ug iej
s tro ny .
n ie
przernawia
za
w laczen ie m
go
do
P r ze prowa d za j ac s tud ia n a d Iauna trylobi tow gor no -ordowickic h (glcw nie z poziom u ze St a u r ocephalus cl avijrons) z Oor S w ie tok r zys k ich i Br ze zin k i (Kie lan , 1955 i 1956) oraz porownujac
t~
mi e jsco w osc i Wol ka
Ia une z trylob itami go r no -ordo -
wickimi S k an d yn a w ii i Wie lk ie j B ry t a.n i.i. m ial arn do dy spozycji wie le d ose dobrze
zac howanyc h okazow ro dzaju Staurocep h alu s. Za pozn a n ie sie z Jeso m orfolog ia d op rowa dz ilo mn ie do w niosk u po twic rdzajacego pog la d K in ga , ze Staurocephalu s wi nien bye wyk luczony r own iez z rod ziny E nc r inu r id ae. Dowodo w n a to, poza budowa
h ypos tomu, d os tarcza m or folog ia pyg ldium oraz przebi eg wentral nyc h szwow twar zowych i kszta lt r ostrum u tego ro dzaju .
Cech a d ia gnost yczn a ro dziny E n cr in ur id ae jes t bu dowa pyg idi um . Wszystk ie in ne
cechy c harakteryz ujace te rod zine , po dawa ne p r zez S chmidta (1881), Hupe (1953) i in ny autorow, wystep uja r owniez u pew nyc h przeds tawicieli Pliome r id ae i Cheirurid ae
i dl atego n ie m oga bye tr alctowa ne ja'ko p ar ex ce lle n ce charak teryst yc zn e dla Encrin ur id ae . P ygidium E ncrinuridae charakteryzuje sie du za lic zb a segrne n tow r achi a ln ych i s tos u nkowo zn a cznie m n iej sza liczb a seg rne n tow pl euralny ch . Mal e pygid iurn
staurocefa lusa, z 3 p ierscieniarn i n a rac his i 3 pl eurami wy d luzo ny mi w kolc e, jest
zupelnie od mie n ne od pygid ium chara kt e rysty czn ego dl a Encrinurid ae. Zb ad an ie d ob rze za chowa nyc h cefalonow S. cla v i,frons z· Gor S w ie tok rz ysk ich or a z S . cf. 1Jwrchisoni z An gli i wy kaza lo. ze rost ru m sta urocefal usa jest n ie zmiern ie duze, zt ozone
z d wo ch czesci . J ego czesc przednia j es t wy pu kla i s ta n owi b ezposrednie przedluzenie wzde tego przednie go plata gl ab ell i ; czes c ty ln a jes t mn iej sza , drobno granulew an a i m a k sztalt trapezoidaln y (fi g. 1 i 3). T en ty p r os t ru m j est zu pe ln ie odmienn y
od rost r ow u przed staw ici eli Encr inurid ae, gd zie jes t one male, je d no lite i zazw yc zaj
bardzo wask ie , i s ta no wi da lszy fakt przern a w ia jacy za wy dzie lenie m s ta u rocefa lusa
z tej ro dzi ny.
TRILOBITE FAMILY STAUROCEPHALIDAE
177
W gornym ordowiku i w sylurze r od zaj Staurocepha!us wykaz u je sze ro ki e ro zprzestrzenienie geog r aficzn e. Ze srodkowego ordowiku n ie byl on d ot ychczas wzrniankowa n y. W pracy nini ej szej opisany jest najstarszy zn any Staurocepha!us, oznaezony
ja ko Staurocepha !us sp, a, po ch od zac y z w arstw srodk owego or dowiku , poziorn Z D icranograptus dingani, z Norwegti . Gatul1;ek ten ro zn i si ll od g or n o- or d ow iok ich i sy lu r -
sk ich orzedstaw ici eli rodzaj u Staurocepha!us gtow nio mni e j wzde ty rn rprzedn im pi atem g la be lh i odrniennym w ykszt.alceniem trze eie j bruzd y bo eznej {fig . 4 ; p l. IV,
fig . 3). Wentralne szwy twarzowe [ sp odnia stron a ce talonu nie zachowaly s ill u teg o
ga tu n k u . Studia n ad bud owa r ostrum i przeb iegi em wen tralnyc hszwow twa r zow y ch
u S . davifron s i S . cf . murch i soni p oz wa la jq wyobrazic so bie j a k wyg la da lo wyksz ta lee nie tyc h e le rne n tow u przypusz czal ne go przod ka s ta urocefa lu sa . Wyda je sill
p rawdopodobne, ze w zw iazk u z wzd eci ern p rzodnie go p lata g la belli , w toku ewolucj i
rod zaju Staurocepha !u s, p ierwotny, otoczon y za b ka rni brze g c ef alonu zos ta l przesun iety p od sp od wz d e tego pl at a. W ta k iej pozycj i znajd uje s ill on u S . cl avif r ons i S. cf .
m u rc h i son i (fig. 1 i 3; p l. I , fig . 1 c; pI. II , f ig. ' 2 b) . S zew rost ra lny na torni a st prze-
s u na l sill z pi erwotne go brze gu ee fa lon u -
n a obee n y jego brzeg, gdyz tylko w tyrn
po loze n iu mo ze on b y e Iunkcjon alny w ezasie linien ia . W zw iaz k u z tym pl ytk a
r ostralna znaeznie sill powie kszyla i sk la da s ill z d wo ch czesci : pierwo tn e go r ostrum,
s ta now iacego obeonie tyl na , subtoapezoida lna czesc u-ostrum u S. dav ifrons i S. cf.
mu r chisoni, or a z z czesci p rzedn ie j, s ta n ow iacej bezpos r ednie przcd lu zenie w zd eteg o
p r zednie go pla ta , nal ez ace] pi erwotn ie d o glabelli.
Rodzaj O edicyb e! e Whittington, 1938, zn any by l do tyc hc za s t y lko z k ran idi ow,
w zw ia zk u z czym je go st a n ow isk o sys te m a tyczne b y lo niej asne. (Rodzaj J emte!!a
Thorslund , 1940, tra kt owany jest tuta] ja ko sy no n im O edicyb e!e) . Mialam do d ysp ozy cj i sze reg ca lyc h okazow O edicyb e!e k i ngi Whittington z gor nego or do wi k u Gor
Swietokrzyskich i Szwecji (fig. 5; pl. V i VI). P orown an ie ca lyc h panc erzy rodzajo w
O edicybeLe i Stauroe epha!us w yka zal o (fi g. 2 :i 5), ze po dobien stwa m ie dzy tym i ro -
d zaj ami sa zn aezne . U o b u r od zaj ow
g la be lla
sk la da
s ill z w a s k iej , tylne j
eZllSCI
z 3 parami b ru zd boczn ych i bard zo w yp ukte go pl ata p r zedniego. T oraks u Staurocepha!us rna 10 seg rne n tow , a u Oedieybe !e -
11, lecz ks zta lt pl eur jest u obu rodza-
jaw podobny. Wreszcie oba rod zaj e ch arakteryzuja ud erzajaco podobne male p ygidi a ,
o 3 segrne n ta ch rach ialnych (ni ekiedy 4 u Staurocepha!us) i 3 ple u r ach, w yc ia g n ie tych w
s k ie r ow a ne ku tylowi ko lce , P r zeb ieg w entralnych sz w ow twarzowych
i k sztalt ros tru m jest u O edi cy b e!e n ie k om pl e tn ie znany, istniej e jednak pewne
prawdopodoblenstwo, ze rodza] ten rna rowniez duze i szer ok ie rostrum.
Opiera jac sie na w yzej podanych faktach, rodzaje Staurocephalus i Oedicybele
zostaly w ni niejszej pracy wy dzielone zarowno z Che ir u r id a e , j ak i z Encrin u r ida e ,
i u mi eszczone raze m w c drebnej rodzi n ie Staurocep ha lid ae .
Acta Pa laeontologlca P olon lca -
vol, II/2 -3
12
ZOFIA KIEL AN
178
O BJAs N I E N I A DO ILUS TRACJI
F ig. 1 (p . 162)
S ta uro cep h a l us cf. m urch isoni B arrande - nieco sc hema ty czn y r ysunek cefa lonu
ad s trc ny prze d ni o- boczn ej; R. P. plytk a rostra Ina, R sze w rost ra ln y , F sze w tw a rzowy, C szew kon ek ty w n y (0 . M . - C. 306); :< 5.
F ig. 2 (p. 164)
Stauroceph a lus cl avifr on s An ge lin -
r ek on struk cja ; X 8.
F ig. 3 (p . 166)
r ekons trukc j a ce falon u ; A wi d ok od st r ony
grzb ie to we j (lin ia przerywa na wskazu je p r zebieg szw o w i brze g cefa lo n u , a ciem ne
p la m ki (S ) - kolc e marg in a lne. na sp od nie j s tro n ie p lata cz oloweg o g la be lli ), B zary s
p ro fil u . R szew r os tral ny , C szew kon ekty wny , R.P . p ly tk a ros traln a , S k olec ; X 8
S ta urocephalu s cl avi f ro ns A rigel in -
F ig. 4 (p . 168)
StauTocep h a lus sp a . - SI ' S 2 i S 3 o ierwsza . d r ug a i trzecia bru zd y boczn e g labe l!i;
trzec ia b ru zd a sk la da sie z 4 m a ly ch wg leb ie n (P l -P ) (P .M .O.- 67044); X 24.
F ig. 5 (p . 173)
O edicu bele king i Wh it t ing ton -
r ek ons tr u k cja (n ieco s che ma ty czna ): X 8.
P I. I
Stau r ocep h al u s cf . m UTchisoni Barr a n de
F ig. I. F ra gme n t ce fa lon u i tor a ksu : a od s tr on y g rz b ie tow ej, b z bo k u , c od
s tr on y b rz u szne j . Na fi g. 1b i l c wi d oczna j est p lytka r ostr a lna, przesu n ie ta ze s wego
p ierwo tne go po loz enia . Sy lu r , wap ie ri wen locki ; W ielk a B r y ta n ia , Dudley (B. M .- J. 7960) ; X 5.
O kaz p ok r y w a n y ch lo rk ie m a m on u .
PI. II
S t auro cep ha lus cf. mUTch isoni B a rran d e
F ig. I. Cef al on - wi dok z bok u : w id oczny przebieg szw u twa r zo w e go i rostraln ego . S zw y ko ne k ty w ne, b iegna ce w za cieni onej czesci, ni e w idoczne na fotogra ffi.
P oziom i mi ej sco w osc - jak d la okazu na pl. I (B. M . - 9. 1'~79) ; X 5.
F ig. 2. Okaz zwin iety, wi doczny z boku i od s tr on y brzuszne j, N a fi g . 2a w idoczny przeb ie g szw u twarz owego i r ostralnego, n a f ig . 2b - pr zebi eg szw ow konektywnyc h ora z p ly t ka rostralna . Poziom i mi ej scowosc - jak d la okazu n a pl . I (0. M . C.306); X 7.
O kazy p ok r y wa ne ch lor k iem a mo n u . PI. III
S ta uToc ephalus sp . b
F ig. 1. Cefa lo n w id oczn y od s trony gr zb ie towe j , z p rz odu i z boku . G orny or dowi k , 1 m ponizej czerwo nyc h mulowcow tr e tap isow y ch ; S zw ecj a , Dal arn a , Skalb erget, po l nocny p r ofil (U.M. -D.543); X 6.
179
TRILOBITE FAM ILY STAUROCEPHALIDAE
Staurocephalu s cla v ifrons An gel in
Pra w ie ca ly os ob n ik - odlew z: lateksu . Gorn y or do wi k, poziom ze
St au r ocep ha lus clavifron s; P olska, Go r y Swietokrzysk ie, Brze zinki (1.G. - 2.II .1); X 5.
Fig. 3. Pygid ium - odlew z lateksu . Gorny ordowik , po zi om ze S. clavifrons ;
Polska , Gory Swietok rz yskie , Wolka (1.G .-2.I1.2); X 12.
Ok a zy pokry w an e ch lo rk ie m a mo n u .
F ig. 2.
PI. IV
Staurocephalus cla v ifrons Arigel in
F ig . 1. Kra n id ium - ok a z przed s tawion y prze z A ngeli na (1878, pI. 34, fi g . 8)
GOrny o r d ow ik , w ar stwy s ta u r oce f a lu sow e ; S zwecj a , Ves tergotland , Alleberg (R.M.A r .8271); X 6.
Fig. 2. Praw ie ca ly osob n ik -
odle w
z
la teksu.
Gorn y
or d ow rk,
poziom ze
St all ro cep h al ll s cla v i frons; Polska , G ory Sw iet ok r zysk ie, Brzezinki (1.G .- 2.I1.3) ; X 5.
St au r oc ephalus s p. a
Fi g . 3. Kran id iu m . S rod k owy or dowi k, po zi om z Di cra n ograp t us cl inga ni; N orw egi a , ok olice Osl o, T erneholmen (P .M .O. - 67044); X 12.
St aurocephalu s sp. c
Fi g . 4. Kra nid ium . G orny or do w ik, czerwo ne mul ow ce t r et a sp is ow e ; S zw ecj a ,
V est er got la n d , Skoga st or p (U .M. -Vg .711) ; X 12.
F ig . 5. P y g idium. G orn y o r d owik, cz e r w on e
Vesterg otla n d, S k ult orp (U .M.- Vg .710); X 12.
Oka zy p okrywa ne ch lo r k ie m a m on u .
m ul owce
t r et a sp isowe; S zw ecj a
PI. V
O edicyb el e k ing i Wh ittingt on
P r aw ie ca ly osobni k - od le w z lateksu . Gorny ordow ik, p r a w do po dob n ie p oziom
ze Stallro cephalll s clav ifr on s; Szw ecj a, Scan ia , Ro st an ga (L. M .-CO 3874 t) : X 12.
Oka z pokry w a ny ch lo rkiem a m on u .
PI. VI
O edicyb el e k i n gi Wh ittin gt on
Fig. 1. Kranidium. Gorny or dowi'k, warstwy tretaspiso w e ; B ornholm, Vasagaard
(C.M.- 1917.188); X G.
F ig . 2. Cefalon . Gorny or dowik , pozio m ze St aurocepluiui s
Gory Swietokrzy skie, Brze zinki {1. G. - 2.11.4); X 6.
cl av i f r on s; P ols k a ,
Fig. 3. Cefal on i frag m en t t oraksu . Gorny or d owi k , p oziom ze S. cl av if r on s; P olska , G ory Swietok rz y skie , Wolka (1. G . - 2.II.5) ; X 6.
F ig . 4. Cefal on , z w idocznym od ci skiem brzusznej s t r on y pl at a czolow ego. Gorny
ord ow ik , poziom ze S . clavifrons; Polska , Gory Swi etokrzy s k ie , Brze zinki (1.G.2.II6); X 10.
Ok a zy p ok ry w an e ch lo rk ie m a m on u .
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EXPLANATIONS OF PLATES
PI. I
Staurocephalu s d. murchison i Barrande
Fig. 1. Fragmen t of the ce ph a lon a n d thorax in dorsal (a) , lateral (b) a n d ve n tr a l (c)
v ie w s. Fi g. Ib and lc show the ro stral plate remo ve d from or igi na l position .
Silurian, Wenlock li mes to ne; G r eat Brita in , Dudle y (B.M. -J. 7960); X 5
The spe ci m en s coa te d with a m mo ni u m ch lo r ide.
P I. II
St aurocephalu s d . murchi son i Barrand e
Fi g
1. Ce pha lon in la teral vie w , sh owi ng th e cours e of the facia l a nd r os tr al
s u tu res . Connectiv e s u tures runn in g in sha dowed part n ot visib le on the
photograph. H or izon a n d locality - as fo r pI. I (B.M.-9.1579) ; X 5.
F ig.
2. Enroll ed spec im e n in la tera l a n d v entral views. F ig. 2a s h ows the Fou rs e
of t he fac ia l e nd r os tral su tures; f ig. 2b s hows the co u rse of th e con n ective
s u tures a n d th e ros tra l pl ate. H or izon a n d locality - as for p I. I (O:M. C.306); X 7.
The s pe cim e ns coa te d with a m mo ni u m ch lor ide .
P I. III
St au r ocephalu s sp , b
F ig.
1. Cep ha lon in dor sal, fron ta l a n d la teral views. Up pe r Or d ovici a n , I m be low
t he Red Tr etaspi s be ds ; Sweden, Dalarna .. S kal be r ge t , no r the rn sec ti on
(U.M.- D.543); X 6.
S ta urocephalus cl av if rons Angel in
F ig. 2. La te x ca st of a n earl y entire in d ivid ual. Uppe Or dov ici an , zo ne of Staurocep ha lus cl avifr ons; Poland, H oly Cr oss M ts., B r ze zink i (I.G .- 2.II. I); X 5
F ig. 3. L atex ca s t of the pygldium . Upper Ordov ician, zone of S. clav ifrons; P ol a nd ,
H oly Cro ss M ts ., Wolka (I. G.-2.II .2); X 12.
T he spe cim ens coate d wit h am moni u m ch lo ri de .
PI. IV
Stauro cephalus cl av ifrons Angel in
F ig.
1. Cran id iu m - the speci me n fig ured by A nge lin (1878, pl. 34, f ig. 8). Uppe r
Ordovician , Stauroceph alu s b ed s ; S wed en, Vestergotland , A lle be rg (R.M .Ar. 8271) ; X 6.
F ig. 2. Latex cas t of a n early e n ti r e indi v id ua l. Upper Ordovicia n , zone of S. cla vi f r on s; P oland, Holy Cross Mts., Brzezink i (1.G.-2.II.3); X 5 .
Sta ll r ocep h al u s s p . a
F ig. 3. Cr anid ium. M iddle Ord ov ician. zone of D i cr ano graptu s clingani ;
Osl o region , Terneholm en (P .M.0.-67044); X 12.
Norwa y
Stau r ocephalll s s p . c
Fig. 4. Crani di um. Upper O r dovicia n , Red Tr et asp i s be d s ; S wed e n , Veste r gotl a n d,
Skogastorp (U ;M.-Vg.711 ); X 12.
F ig. 5. Pygid ium. Upper Ordov ician, Re d Tr eta sp i s beds ; S wed e n . Ves te rgot lan d .
S kultorp (U .M.-Vg. 710) ; >~ 12.
The s pec imens coa t ed w it h a m monium ch loride .
PI. V
O ed i cyb el e ki ngi Wh itt i n gt on
La tex cas t of a nearly e ntire indivi d ual. Uppe r Ordovic ia n , pro ba b ly zone
of Stauroc ephalu s cl av if rons; Sw ed e n, Sca n ia , Rost an ga (L. M.- LO 3874 t ) :
X 12.
T h e spec im e ns coa te d wit h am mon ium ch lorid e.
P I. VI
O ed i cyb cle ki ngi Wh ittin gton
F ig.
F ig.
F ig.
1. C ranidi u m . Up p er Ordovic ian . Tr et aspis beds ; Bor n h olm , Vasa gaa rd (C .M.- 1917. 188); >~ 6.
2. Cepha lon . Uppe r Ordov ician, zone of Stauroc ephalu s clav i frons ; P oland .
Holy Cr oss Mts ., Brzezin k i (1.G . -2.I1.4); ;< 6.
3. Cephalon a n d th e f rag men t of thora x. Up pe r Ordov ician , zo ne of S . cl av i f r on s; Poland, H ol y Cr oss M ts ., Wolke (LG. -2.II.5) ; X 6.
F ig. 4. Cephalon sh owi ng the im p r int of th e ven tra l si d e of the fro n ta l lobe. Upper
Ordovician, zone of S. cla vifron s; Po l-and, H ol y Cross -Mts ., Brze zinki (1.G .2.11.6) ; X 10.
The s pe c ime ns coa te d w ith a m mo n iu m ch lo ri de.
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