ON THE PARASPHENOID OF THE BRACHYTHORACI The first

A
eTA
vet . I
PALA
EO;\,TOLOGICA
POLONICA
1 956
No . 2
JULIAN KULCZYCKI
ON THE PARASPHENOID OF THE BRACHYTHORACI
A bst rac t . - A description is given of the Brachythoraci parasphenoid as compared
w it h th e corresponding structure dm Aoant~idiiJalIl!S and some Crossopterygnans (Por olsp id ae jvand ',viloh dhe Acanthodierr -anter-ior-basai .
I NTRODUCTION
The fi rst desc rip tion 0.£ the parasphenoid 0.£ the Arthrodires was made
by E. S. Hills (1936) upon discovering inthe endocranial floor of 1Jhe Coccosteus (= Buchanosteus) osseus the presenceof 'a " thiokened part compos ed orf solid bone' with a s om ewhat complicated structure.
A dermal element, coating the very same region of eIIldlOcT'ani~m of
I
Kujdanovia spis buczacziensis but showing a much simpler structure, was
des cr ib ed by E. A. Stensio (1942).
. In an. addendum to his next paper on the cramum and cervical jodnt
of cth e Dolichothoraci (Acanthaspida) (1945), Stensio is 10010 'the conclusion thetthe dermal ele ment, decribed by him and by Hidlsvconstdtutes
the p ar asphen oid. In the same paper Stensio writes thaJt in certain Brachythoracid Arthrodires from Wildungen (Erromenosteus, Trematosteus ,
Brachyosteus) he had ascer-tain ed ,t h e presence of the parasphenodd, shaped as .a powerful bone, e xtend in g, as it does in the Crossopteryglans
and most of the Paiaeonisciformes, backwards to underneath the transi tion al part between t h e orbito-temporal an d the otic regions of the
endocr anium. E . A. Stensio believes fu :at th~s element' is provided with
a paired processus ascendens,
In th eir paper on the anterior superogn athal of Gorgonichthys, D. H.
Dunkle and P. A. Bungart (1946) published a dJr.aiWdalg representing the
parasp henoid of Dini chthy 3 t erreUi amd Hei ntzichthy s gou ldii mentioning in the text fhat the SUiPeI':ognartlha:l elements are iJnJtimaJtely associate d with a parasphenoid-ljke plate which is apparently to be homologised
with the arsterior-basal element of the Acanthodians.
The most recent reference to this element, here under consideration,
is to be found iJn a paper by E. Jarvik (1954). When speaking of his
hypothesi s concerning the developmenr of parasphenoid in fishes, that
104
J UI.I AN KULCZYCKI
author expr esses an opinion that in the Arthrodires the home, as m enti on ed above, r ep resents a primitive t yp e of st ructure, apparently w ith out
ascending p rocesses. Basin g h is state men t on an u npublished paper by
S tOOo9i6 h e a lso alleges that th e developmen t of the p arasphenoid in
Arthrodires is characterised b y d isin tegrati on 'a n d r ed uc t ion.
Kujdanoviaspis bucza czien sis and Bu chanosteu s osseus are the only
r epresentatives of 'the An throdires w hose parasphenoids have be en reported upon at any l engrth . Since, as sh own by S t ensio, b oth, th e latter
of t hese forms , as well as Ku jd anoviaspi s, belong to. t he Arctolep id a, n o
de tasled d escription of t he p ar asphenoid of Brach y thorac i is th us far
available.
T her e a re three sp ecimen s of these bones in the fo ss il m a ter ial d ep osited a t the Muzeum Ziemi (Museum of the Ear th) in Wa r szaw a a nd
collected by l ate Mrs. Z . Gorizdro-Kulczyck a in ,'fue Upp er Dev onian of
Kieke. Tw o of them w ere discovered in association w i th o ther skull
fragments b elonging to DinichthYJ d . pu stulosus , and to 'the represen tative of a new genus of Brachythoraci, probably cl osely r el ated to
Pholidosteus. A d escr ip tio n of these fragments will be given, in a forthcoming paper. No fossil r em ains were found associat ed w ith the
th ird specimen. L
a nd d:ts generic and family appu r tenan ce, cannot,
therefore, be establishe d . Never-thel ess its close r esemblance to the
parasphenoid of Dinich th y s te rrelli and Heintzicht h y s gouldii as figur ed in the drawing by D unkle and Bun gart , testifies to its refel'ab ility to the Brachy ithorac i. This sp ecim en is in the m ost complete
state of p r eservation of the three a t th e writer 's disposal. T hrough treatm ent in acetic acid som e of i ts very d elicate structur al details h ave
been disclosed and it is on this specimen that th e writer has b as ed h is
p r es ent description of the parasphenoid of Br ach y thoraci.
The writer's thanks are due to Prof essor D . W . Obrutseh ew of Moscaw
a nd to Dr. D. H . D enis on of Chicago for the valuable h in ts r eceived. from
them by way of correspondance w h ile he was workin g on h is description
of Devoniari fishes fromth e Holy Cross Mts. H e is a ls o p articularly mde bted to P rofessor W. Gross of the Berlin Hum b old t University for
makirng accessible to him the collection of fosssl fishes <lit the university's
palaeontclogicad institute, and for ,tJhe fniendly advice extended to the
writer during h is brief visit a t fh e laboratory op er a ted under the managemen t of Prof. Gross .
D ES CR IP T IO N
The paraspheno id of the Brachyfhoraci displays a r ather complicated
structure. Two parts may b e differentiated in t his h one, n amely the
anterior (pa) tin the form of a s trong plate w ith a su b -cordate outline,
ox
H IE P ARASP HDIOID O F THE BRACH YTHORA C I
105
t er minating in a sharp ap ex projected anteraoriy, and the posterior (pp.)
tran sv er s ally elongated , th ick around the m idpoirit and thin a round th e
e dges .
T r an sversally the an t erior cor dat e p ar t (pa .) .is somewhat conca ve on
t h e vent r al sid e, and convex dorsally . A t th e sa m e tim e its lateral edges
rather mm up in the dor sal direction, p anticular'ly so in rts broad posterior region . Longitud in all y t he ante rior cordate p art bends graduall y
dorsad as it approaches itsantenior limit. On the ventral sid e, along the
mid -line, a longitudinal crest (cr. m .) occurs in s ome forms (though abs ent in t he sp ecim en incertae fam iliae, showing the b es t state of preser vation ), mor e or less sharply ed ged , w ith h eight in cr easing anterior ly.
Its basal wid th increases in the s ame direction. The cres t is par tic ular.ly
d istinc t in the parasphenoid of Dinicht h y s cf . pustu losu s where it r eaches
tcfhe an terior en d of th e elemerrt iand rt er rninates 'i n a sharpened process . In t his form the longutud in al cr e st p asses posteriorl y into a rather
small fl at area (a. tub.) spotted b y minute tubercles iden t ical to those
fo u nd on the external surface of t he d ermal bones of the skull. A longitu din al g roo ve r uns dorsally along the mid-line of the a n terior cordat e
par t of the p aeasphenoid (sm.). The free bon e edge is grooved and serrated.
The p os ter ior p art (pp .) is un fortunately in 'a state of incom p lete prese r v ati on. T h e lacking d etails a re the m ore delicate marginal p arts , in
th e form of t hin lat eral lamell ar processes (prl. v .), situ ated ventra ll y ,
w hose ou tl in e h as b een fi g ured b y D unkle an d Bungart (1946) In their
drawing of t h e p arasph enoid of Dinich th y s t err eHiand H eintzicht hy s
gou ldii. On the b ase of the cited drawing it may b e :iJnf,eu-r ed, th at these
processes are very well d evelop ed in Dinichthys terrelli , w hile irn H eint Z i ch t~ ys gouldii they ar e r a ther rudim entary.
Th e p osterior part of t he parasp henoid of Br a chythor aci t ran sv er sally
so mew h a t con cave, prese nts a p erfectly smooth and even ventral surface,
Jack in g an y d etails . It is separ ated from the anterior corda te part by a distin ct transverse gr oo ve (s. tr.) w h ose course across 'fu e el ement is tr aced
a t an angl e with anteriorly p oint e d ap ex . Medially the gr oove is partitio n ed by a bon e lamella pierced b y a large foram en communicating w ith
t he le ft and right p ortions of the groove. 'Dhis gives the semblance of
a delicate bone -b ridge spanning the oern!uml r egion of the groove (p .).
The ven t ral side olf iJhe b ridge p aJSiS€ S wirth mo signs of demarcation to the
ve n t ral surface of t he anterior c orda te p art, w hile f rom the posterior
part ,i t is se p arated by a narrow groove ccmmun icating a t b oth ends with
the t r ansverse groove w hich transac ts th e w hole elemen t. Close to the
bone m argin a minor groove bran ch es off on b oth sides into the dransve rse g roov e (pl, II, fi g. 7) and traverses t he lateral s urface running 00-
106
J ULI AN KULCZYCKI
t eriorly to the dorsal side of thearst eriorcordate pa.rt of the e lement,
where it soon d isa pp ears. In the mid-p art of the gro ove, on both sides
of the m edian bridge , there are two sym m e trically arranged , faiTl y
l arge foramina (c. aci.) separat ed by a b one lamella (pl. I, fig. F ; pl. II .
fig . 6), vertically piercing 1Jhe parasphenoidand communicating w ilith a basin-like depression situated centraily on the d or sal side of th e elem ent.
A r ather small ridge (cr. fh.) is found b etw een the two foramin a of the
depression, w ith its one end coalescing imp e rcep t ib ly w ith t he front wall
of 't he depression, w h ile t he other end t erminate s as 'a fnee proce ss on the
b ack wall. From the foramina aft the f loor of ith e hypophy seal d ep r ession
(f h. ), t wo somew h at divergent furrows run across the fmnt w ail. The
wal'ls of the depression which , frontally , r ath er gently p artition off the
posterior part of the parasphenoid from theanterior cordate part, at t h e
hack d rop d own s teep ly toward the t hin list of t h e poster ior rim. On the
sides they form sub-even, triangudar p rocesses (prl. d.), transec ted b y
a deep notch. From underneath these, branch off lamell ar lateral processes of the dors al side, as mention ed h ere abo v e.
The present des cription has been based on the sh ap e of the parasphenoid in Brachythoraci incertae fam iLiae and of the specimen referable to
Dinichthys cf . pu stulosus . As f igur ed in the d rawi:ng by D un k le and Bungar t, It a lsoagrees with the st ruc t ure of t he parasphenoid in Dinichth y s
1 erreHi and H eintzic hthys gouldii.
Though th e b ad stete of p r eservataon is a h indr ance in the way of observations, y et it would s eem thaJt' the parasphenoid belonging to a
new r epresentative of B rachythoraci is of a somew h at different structure.
It sh ow s a similar curve in the anterior part; vencrally i t also is provided
with a longitudinal crest t hough not so stron gly developed as in Dinichthys cf. pustolosu e. Further , it prob ably lacked the t ransverse gr oove
as well as ith e bridge and foramina pi ercin g the element art m id-line. In
rts dorsal region there probably ex is ted a single , blind, funnel-lik e p it
poorly w alle d in. .
DIS CU S SIO N
In its shape th e parasphenoid of the B r achyithora cl di ff e rs con sidera bly from the correspondmg elem ent in Kujdanoviaspis buczac zie nsis
w h ere it is a Ha t r hornb iforrn plat e, strew n w ith minu te t uber cles an d
p ierced at mid-poirrt b y the hypophysial Ior amen. In this r epresenta tive
of t he Arc tolepida the elem ent here con sidered ds in rio w ay relat ed to
th e internad carotids w h ich p enetrat e t he sk u ll l ater ally from the parasphenoid.
The shape of the parasphen oid in Bu ctumost eu s osseu s i s an in terrned iata form between th at in Ku jda novi aspis and in s uch r ep r es entat ives
ON T HE P ARASPHENO ID OF T H E BR ACH YTHORACI
107
of Bra ch y thor acras Dinichthys and He intzichthys . It is also 'a rhom biform
plate strewn with tubercles arranged along a somewhat radial pattern .
On the other hand, instead of the single hypophysial forarnen, two for amina w ,HI be h e re encountered ad m ild-point, partntioned bya bone lamella. Beh ind 't hes e foramina there is 'a transverse groove w hich, in the
opiri ion of E. S. Hills, unites wdthfhe blind sac- Iik e pits a nd commun icates on each side with the canal w hich opens on the late r al bone margin.
E. S. Hills favours the supposition that these two foramina are the h ypophys ia l canals, in spite of his OW!Il assertion that he knows of no case in
which h ypop hysis, eit her in em bryonic or adult stages , w as paired, That
au thor also supposes that the lack of lamina in the hypophysial foramen
in Ku jd ano viasp is may have resulted from t he ba d state of p reservation
of the specimen (1946 , p . 218 : " ... al though in a poorly preserved s peci m en
it is qurte possi b le that rthe duplicate n ature of this canal would n ot be
obser v able " .
This interpret ation m ay be doubted not only owing to the unpaired
nature of the hypophys is but als o the str ucture of the par asphenoid in
Din ichth ys and Heintzi ch thys. As ma y be inferred fr om t he precedin g
descr ip t ion , the paired foramen is in these forms situated wirtJhin t he
transverse groove , which testifies to the m u tual associ a tion of these two
str u ctu r es . Further, in between t he groove fooamimlaa bone-bridge is
enc oun tered, which m ust h av e served as protection of some connecting
struct u r e. It seems rather improbable forrthe glandular ducts. to have
developed a IlJetwJOI'Ik of this kind. It mightraoher b e jnfe rr ed th,at intern ai carotids , connected by anastomosy running und ern ea th t h e b r idge,
passed through the pained foram en. As mentioned b y Hills and as is to
be seen from his drawings, the parasphenoid ,in Bu chanost eu s osseus has
b een damaged anthe region of tih e ·"bHlnd sac-like pits vand canals lead ing
to the tran sve rse groove . :Lt would appear t h at this m ight have le d to
w ant of exactitude in recon struction and that the " bEnd sac- like pits"
may b e p acts o f canals opening on the lateral m arg in of the p arasphenoid.
Yet on the ro th er h and, the absence oif any grooves or canals whatever,
leading to the h yp ophys ial f orarnen in the Ku jda n oviaspis buczacziensiJ
bars all other in terpretat ions and s uggests incorrectness in Hills ' s up p osit ion that ,t h e had s tate of p reserv ation may 'be r esponsible for th e absen ce of t he bone lamella.
It is t he probable a bsence of paired foramina, as well as that of the
,transver s e groove on the parasphenoid of t h e represent ative of the new
genus of Br ach ythoraci t hat p rohibirts full centairrty in confirmmg the
correctness of interpretatacn in the case of t hese fo r amina, More constan cy is r1Jo b e expected ill vessels of such significa nce, th oug h in t h e
c ase of r ays, for instance, t hey vary t heie behaviour, en terin g in to the
108
JU l. !.;"
KULCZYCKJ
sk ull cavity eit her indep enden tly by m eans of paired foramina, or again
by means of a single on e.
As abo ve cited, the fo rm her e considered probably approaches genus
Ph oiuiost eu n, which, with r esp ect to so me of i1ts characters, is mor e pr imrtive th an the Cocco st eus and repres ents an independent line of ev olu tio n
of the Brachythoraci. There isa chan ce, therefore, th at a somewhat differen t course was taken by its internal car otids which penetrated the
skull laterally in relation t o the parasphenoid, as in the case of K u jd an oviaspis buczac ziensis, while th e transverse anastom osy, if it did exis t,
might h ave run very superficially, either a n the ventral or on the- dorsal
side, without leaving signs of its course an the p araspheno id.
In conformity with the above, the parasp heno id in Buchan ost eu s
osseusand in Brach y thoraci wo u ld not be provided with the hypophysi al
Iorarnen p r es en t .i ri K u jdanoviaspis buczac ziensis. Since the presenc e o f
1he hypophysi al Ioramen is a prim ary character, while its a bsence a se condary one, we mu st recogru is e when a ccep ting the a bove rirnte rpr e tation .
that: t he parasphenoid in K ujdanoviaspis buczacziensis r epresents a "mor e
primitive stage than that encoun tered in Buchanosteu s osseus an d t he
Brachythoraci.
Similarity in structure of the p arasphenoid, r eferable to Buciumosteu s
and that of Brachythoraei, is one more proof testifying to the close relationship between the latter forms and Arctolepida.
A s mentioned above, the presence of the hypophysial foramen on t he
pa casphenoid of Kujdanoviaspis buczac zi ensis implies small probability
to the s uggest ion that simplicity of str uctu re in this elem en t is referable
to second ary simplification. In thi s connection H is to be inferred that
the evolution of the p ar asphenoid within both, Arctolepida and Brachythoraci, h ad taken place independently from that within other s tooks of
fis hes . The r esultlngcharacteristic shape of the bone persisted in Bra chythoraci zo tJhe end of their existenc e. In asmuch as the relationship between other representatives of the Arthrodires with those under consideration, has 110't been adequately clar ified and t alking imt o accou n t that no
decisive evidence has b ee n supp lied showing some stage of r educ tion
of It he parasphenoid in Arthrodires (it must be a dded that not long ago
the Arctolepida and Brachythoraci were regarded as lacking this skeletal
element) - suggestions concermimg the dtsirutegretion and r educ tion of
th e p arasphenoid in the Arthrodires does not se em justifiabl e in the
light of data now a vailable.
The external appear ance of the parasph enoid of Brachythorac i r esem bles that el emen t in Porolepidae as described and figured by Gros s
(1936) an d Jarvik (1954) . In th ese fishes the par asphenoid is also r el at ively shor t an d b road, w ith a: di sti nct anter.ior part s epar ated from th e
0 1\' Til E P ARASPlI E:'-I O ID OF T H E 13RACH YTIlO lnC I
109'
poster ior one by what Jarvik (1954) h as called prespiracular groove. In
G ly ptolepis t h er e is a hypophysial Ioramen in the m id-line of this gro ov e.
A t fi rst sight t hese morphological d et ails m ay appear id enti cal with th e
t r ansverse groove and ,the pai r ed Ioramen associated with it, as des cr ibed above. Yet , in Porolepid ae , the presp ir acular groove lies s up erficially
on ly covered w ith a mucous Un.ing of the oral cavity. T h is is testified
by the presence of ornamenta t ion. Concrarywise , the ornamentation of the
par as phenoi d of Brachy thor a ci, p ersisting jn Dinichthy s cf. pustulosus,
occurs in t h e anterior co rdate part only , w hile it is lacking in the groo ve .
This condition and the presence of the " bon e-br idge " , whose only pu rp ose cou ld h av e b een .the prot ec tion of under lying structures, b oth testify
t h at t he g roove must have be en associated wuth cer tain anatomic stru ct u r es by the present writer b elieved to 'have been the internal crotids .
It would thus s eem that t he prespiracular groove and foramen on t h e
parasphenoid of Porolepidae cannot b e homologised with the groove and
foram in a on the parasphenoid of Br achy thoraci.
By its external appear an ce the parasphenoid of Brachythoraci also
resem bles t he anterior - b asal e le ment of the Acanthodians, describ ed by
Watson (1937), this be in g stressed by Dun k le and Bun gert (1946). Still in opposition to the parasphenoid of Brachy tho raci, which is a typica l
dermal bon e as testified by its 'h is tologica l structure an d also by the
presence of ornamentation persisting on the pa r as phenoid of Dinich th y.,
cf . pu stulosus - the anterior- basal element in the Aoamthcdians shows
perdohcndrial ossification only. Neither foramina nor grooves for t h e
in ternal carotids Me to b e found on .t he ventral side of the anteriorbasale of the A cant hod ians. Th e forame:n of the h ypop h ysial canal' is
situated in the centre of t his element. F ur therm ore, 'th e anterior-basal
elemen t differs from the p arasphen oid of Bra chy thonaci by a n umber of
ot her , less signif icant characters .
T he lack in the availab le specimen of Brachy tho rac i of that p ar t of
endocr anium adjacent to the parasphenoid, makes impo:ssible a close
an aly sis of t his dermal element in 'its relation to the endocranium, or of
th e relation of its lateral processes to S'imilarr structu res on the a n t er ior
b asal of the Acanthodians and the ascending processes of th e Crossopterygians and .Actinopt er y g iens,
Paleozoological Laboratory
of the Po Ush Academ y of Sci en ces
Wa r szawa , N ov ember 1955,
110
J ULl A:-I KULCZYCKI
RE F ERENCES
D UN K LE D. H . &: B UNGART P . A. 1946. The Arntero - Supragnathal of G or go n ichthys. Amer . Mu s. N ov it., 1316. N e w Yonk,
G ROSS W . 1936. Be itrage zur Osteologie b altischer umd r heimdscher D ev on-Cros sopterygier. P alaeont. Ztschr., 18, 129 - 155. Ber ldn.
H I L Ls E . S. 1936. On certain endocran ial structures iJn Coccosteus, G eot. M ag., 73,
21'3 - 226. Lon don.
·J AR VIK E. 1954. On the vdsceral sk eleton iIn E ustheno p teron with a discussion o f
the panasphenodd a n d patatoquadrate in f ish es. Kung!. Sv . Veten sk. H andL,
S er. F , 5, 1. 1 - 104. S tockholm.
S T E NS IO E. A. 194 2. On .the snout of Anthrodires. Ib idem , S er. 3, 20, 3, 1 - 32.
1945. On t he head s of certadn Arthrodires. 11. On mheoranirum an d ce rv ical
jo iJnJt of th e DoiliJcho t hor aci (Acan thasp ida). I bi d em., S er. 3, 22. 2, 1 - 70.
WATSON D. M . S . 1937. 'I'he Acarrthod iari Fdshe s , P hilos. Tran s. Roy . Soc . L on do n,
S er. B , 228, 549, 49-146. Lo nd on .
J ULl A:-i KULCZ YCKI
o P ARASFENOID ZIE RYB B RACHYTHORA CI
Str eszczen i e
Nota t k a zawiera opts parasphenoideum B r achy tho r a ci z g onne go dewonu K ie1c
o raz IPO,rOwnlarne z o dp ow de dn drn elementem u Acanthaspida vi, ndektorych Cr ossop te r ygdi (P orolepid ae), jaik rownoiez zeeutero-basaue Acanbhodui.
OB J ASNJENI A DO IU 1STl L\ CJ I
PI. I
A antero-b azadn y elem ent Acaruthodid (wg W:wtsona) , B p arasfenodd B uch alwst eu s oss eus tws Hiblsa), C parasfenold D i n i ch thys t err elli (wg Dunkle'a i Bun g arta),
D p arasfenodd H ei ntzicht hys gouldii (wg Dunkle'a do Bungantaj , E p arasfen oid
Glyptolepis, F podl uzny przekro] przez parasfenodd B ra c hythoraci, G p ar asf e n oid
D inichth y s cf. p ust ulos us , H parasfen oi d Bra ch y th or a ci incertae familiae, A , B,
E, G powier zchnia b r zuszna. C, D, H powierzchruia grz bie to wa .
a . tub. pole ip okryrte guzkami, bs. slepe w ozkowate zagtebiende, ca. kanal dla
anaetomozy tetndczej , c. nci. lk an a l d la anteria carotis lilnt erna, c. hypo k ana l .p r zy sadkow a ty . c r. fh. g rzeb ien zag lebiema .pr zy s adkow ego , cr. m. gr ze b ie n sr odkowy,
f h . zaglebiend e przysadkowe, gr. p s p , r owek .preiip irakulcmmy, p . m oste k k osmy, p. a.
przednia s ercowata m;~s c, pp ty ln a-czes « p arasfe no id u, pr], d. g rzb letowy w yrostek
boczny , p r ]. v . b rzuszny wyrostek boczmy, se. m al y r owek z tylu 'k os tnego mostka.
s m . r ow e k srodko wy, s. t r . r owe kpopr ze czny, t. gu zek.
ON T HE PARA SP H ENOlD OF TH E BRACHYTHOR.·\C r
11:
PI. If
F ig . 1 - 2. Paras f enond Brachythoraci n . gen.; 1 - s tron a grzbieto wa , 2 - s trona
b r zuszna ; X 1,5.
F dg, 3. P arast enosd D inichthys d . pust1~l osus., s trona brzuszna; wielJk. nad.
F'ig ; 4 - 7. P ar aefenoid Brachythoraci in certae famili ae; 4 - s trona brzuszn a ,
5 - strona grzbieto wa, 7 - iSUroI11JCl boczma X 1,5; 6 - sr.odJkOWla cz~sc poprzecznego
r owka w r zu cie ukosnyrn, iskaeu jacym o twor iPOd .k ostnyrn m ostkiem d la anastom oz y .t et n iczej ; X 3.
'
IOnl1/1H KYJIb4Y1l1KYI
o
IT APAC<PEHO HAE P b IB BRACHYTHORACI
P eSIOMe
Ilpennaraexaa CTaTbH CO.Ilep mHT OI1HCaHHe n apacrpeaoana .p bI6 Br achy tho ra ci H3
se pxaero ne sona Hensu H er o op aaae an e C COOT3eTCTBYIOl..l\HlVI 3JIeMeHTOM n p en cra RWr eJJeti Acannhaepida 'H HeKOTOpbIX Crossopterygit (P orolepid a e), a r arox e C an r epo6a3 aJJbHbIM 3JleMeHTOM Acamtho dhi .
ACTA PALAEONTOLOGICA
A
POLO~IC A .
J . KULCZYCKI. PLo 1
VOL. I
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B
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Ib. c.aci. crib .
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A anterior-basal element of the Acanthodians (after Watson) . B paraephenodd of
Buehanosteus osseus (after HilllliS), C paraepheno dd of D i n i eh t hy s terreHi (after
Dunk le & Bungart), D paraephenoid of Heintziehthys gouldii (adlter Dunkle & Bungara), E pa'I'l3Ejpheno1d of G l yp t ol epi s, F longatudinal se ct ion of the ,paJl'aspheno :d oil
Brach ythoraci, G parasphenoid of D i nk h t hy s c f. pusrulosus, H .p arasphe no id of the
Brachythoraci incertae familiae, A, B, E, G vent-rail aspect, C, D, H dorsal aspect.
a . tub, tuberculaned area, bs. blind sac-like P'$, cc . OO'IlJaIl for th e aetertal anaSt'OffiOSUIS, e. aei c anall foil' t he arteria oarotds liJnt~l'I1J9. , c. hypo hypophysial camat,
er, fh. crest olf I1Jhe hypophysiral dqpressiom, cr. m. m ed :17!TI crest, fh. hypophysial
de pressdon , gr. psp, IP I1es!P':'r a,cu},aif groove, p. bone-bridge. pa. ant erior cordate P aJI'.t,
pp,posltelf:OII" part of the parasphenold, pr], d. dorsal la'tenad process , pr], v. ven tral
lateral pmee.;-s. se. sma[[ gr oove b ehind ,th e bone-bridge, sm. median groove,
s. tr . transverse groove, t. tubercle.
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.I . I, U I. CZ \ CK I . PLo I1
2
3
4
5
6
Fig. 1-2. P arasph en oid of Bra ch yth oraci n . ge n .; I-d orsal, 2- ven tra l aspects; X 1,5.
l ·ig. 3.
Paraephen oid of Dinichthy s cf. p lls tu l oSHs; v erul.ral as pec t ; nat. size.
Fig. 4-7 . P aras pben oid of Brach ythor ac i incerta e fa miliae; 4-venLrall aspect, 5- do r sal aspect, 7 - lateral as pect , X 1,5; 6 - mid-pant of th e tra nsverse g r oov e
in obliq u e pr ojection s howing the a nas tom otic for arnen und er th e bonebridge, X 3.