PHYLOGENY AND SYSTEMATICS OF PERISPHINCTIDS AS INTERPRE'I D FROM SUTURE ONTOGENIES

TAMAZ LOMINADZE & MEVLUD SHARIKADZE Georgian Technical University, Department of Geology and Paleontology, Tbilisi, Georgia. ILYIA KVANTALIANI Geological Instute of Academy of Sciences of Georgia, Tbilisi, Georgia.

LOMINADZt~ T., SHARIKADZt~ M. & KVANTALIANI I. 1993. Phylogeny and systematics of Perisphinctids as interpreted from suture ontogenies. [Phylog~nie et syst~matique des P~risphinctid~s interpr~t~es ~ partir de l'On- tog~n~e'des sutures]. GEOBIOS, M.S. n" 15 : 275-286.

ABSTRACT Mode of early differentiation of the inner part of the suture line is most important for taxonomy of Perisphinctids. Six types of suture lines can be distinguished, each characteristic of corresponding superfamily : a) the perisphinc- toidal type is characterized by asymmetric division of the internilateral lobe (IlI2), in adult specimens the two branches are non-isolated and aslant ; b) the stephanoceratoidal type is characterized by the formation of a new lobe near the peak of the saddle I/D, on the inner slope of the lobe I and by the following sinking ; c) the olcostephanoidal type is defined by symmetric (IlI1) or asymmetric (I211) division of the lobe I ; d) the desmocera- toidal type by symmetric division of the internilateral lobe (1111) and the formation of sagging suture lobe ; e) the hoplitoidal type by early symmetric division of the lobe I, and by the formation of a generally linear sutural lobe ; and 0 the cardioceratoidal type by the formation of an independent lobe in the saddle I/D. KEYS-WORDS : PERISPHINCTINA, EVOLUTION, SUTURE LINE, PHYLOGENESIS.

R~SUM~ Le mode de diff4renciation pr4coce de la partie interne de la ligne de suture s'est r6v~14 d'une importance capitale pour la taxinomie des Perisphinctides. Ainsi, on peut distinguer six types de lignes de suture, chacun ~tant carac- t~ristique d'une superfamille : a) le type p~risphincto~de montre une division asym~trique du lobe lat~ro-interne (IlI2), les deux branches obliques n'~tant pas isol~es sur les exemplaires adultes ; b) le type st4phanocerato~de est caract4ris~ par la formation d'un nouveau lobe pros du sommet de la selle I/D, sur la pente interne du lobe Iet sur les pentes suivantes ; c) le type olcost~phano~de est d~fini par la division sym~trique (Ili1) ou asym~trique (I211) du lobe I ; d) le type desmoceratoide montre la division sym~trique du lobe lateral interne (Ili1) et la formation d'un lobe arqu~ ; e) le type hoplitoide se singularise par une division sym~trique pr~coce du lobe Iet par la formation d'un lobe sutural g~n~ralement lin~aire ; enfin 0 le type cardioc~rato~de pr@sente la formation d'un lobe ind~pendant darts la selle I/D. MOTS-CLI~S : PERISPHINCTINA, I~VOLUTION, LIGNE DE SUTURE, PHYLOGEN~SE.

INTRODUCTION We have thoroughly investigated the ontogeny of hundreds of suture lines in Perisphinctina. The Perisphinctina represent one of the most signifi- data attained enable us to establish various cant and widespread group of ammonites. They trends in their evolution. are of great importance for the and Cre- When considering the problems of suture line taceous biostratigraphy as well as for the solu- evolution in onto-phylogeny, the mode of for- tion of many questions of ammonites biology. mation of new elements, [indexation of suture 276

(1989) ~o a certain degree differs from the termi- i nology suggested in this paper], their location ,:,,,Vl and pattern as well as the discrimination of ho- I mologous and analogous lobes deserve special at- r tention. The processes of formation and evolution of new elements of suture lines were discussed in historical aspect.

Besidesour own observations, data of other au- thors have been analyzed (Westermann 1956 ; Schindewolf 1963, 1965, 1966 ; Mikhailova 1983 ; Kullmann & Wiedmann 1970 ; Wiedmann & \ ~W2.2 Kullmann 1981 ; Thierry 1975, 1978 ; Shevirev 1960 ; Beznosov 1960 ; Alekseev 1982 ; Shulgina L u ,(D 1985, and others).

Comparison of some ammonoid suture-symbol terminologies is given below (Table 1). ~W0,25 Wedekind- Ruzhentsev Terminology Schindewolf accepted by us

E, external lobe V, ventral lobe V, ventral lobe I, internal lobe D, dorsal lobe D, dorsal lobe L, lateral lobe U, umbilical lobe L, lateral lobe U1, first umbilical I, internilateral I, internilateral lobe lobe lobe U2, second umbilical Ui,first umbilical U, umbilical J lobe lobe lobe Figure 1 - Ontogenetic development of suture line in Macro- vephalites sp. juv. ; sample N301/1, Northern Caucasus, r. Table I Ardon, Lower . 1,2 - first and second lines ; Wl,W2...- first, second and etc. whorls. In most Perisphinctina the primary suture and initial lobe lines consist of five lobes. These are : ventral lobe (V), lateral lobe (L), umbilical lobe tion of the secondary saddle may be considered as (U), internilateral (I) and dorsal lobe (D). The a result of their location on the umbilical seam, ventral lobe is always bifid, while the other lobes where new elements usually are formed and on are undivided. It is noteworthy that in Macro- the other hand of the whorl narrowing in the cephalites the primary suture is sixlobate (Fig. 1). area of primary constriction. The existence of a The sixth element occurs as a result of division of sixlobate primary suture in the above mentioned the umbilical lobe. At the base of the latter a ammonites may also be the result of relatively small secon- dary saddle becomes reduced and high chamber pressure at this early stage of evo- the suture line becomes fivelobate. It should be lution - compared with the period of reduction of noted that a similar pattern is observed in Tetra- the secondary saddle. gonitidae (Schindewolf 1968 ; Mikhailova 1977, 1979 ; Krivoshapkina 1978 ; Sharikadze 1984). In It must be noted, that in and Tetragonitidae, the secondary saddle, which was the formation of new lobes is well ac- also formed at the base of umbilical lobe, beco- celereted, and new elements appear in more and mes reduced at the end of the first whorl and the more earlier stages of evolution. For example, the line becomes fivelobate too (Schindewolf & Kri- division of the lobe I in the Early Aptian Pseudo- voshapkina negated this reduction in Tetragoniti- haploceras takes place at the beginning of the se- dae). There is no doubt, that these data cannot cond whorl, in the Late Aptian Pseudosilesites - be considered as evidence for direct genetic rela- in the middle of the first whorl, in the middle tions between Tetragonitidae and Macrocephaliti- Albian Parasilesites (MIKHAILOVA, 1983, fig.79) - dae. Firstly, the bifidity of the umbilical lobe is on the third line, and in the Early Turonian not always well pronounced in these two groups, Beschtubeites beschtubensis ILYIN (Hoplitoidea, and secondly, the secondary saddle vanishes wi- ) - as soon as in the primary su- thout any trace. It has no influence upon sube- ture (Mikhailova 1983, fig. 106). Thus, also in quent evolution of the lobe. The early formation some Placenticeratidae the primary suture is six- of the umbilical lobe and the subsequent reduc- lobate, but in difference from the above cases the 277

u't VlfVl ^N"b L U | 1)

V v ~#6

W3,7 vl 'qq' r.., ~ \ k/ " '' U ~W3.5 \ ./-V~ w 3 W18s IF'~,L ~J2 hF~ 'r V! L U I2I I D J.. "%2 % ,,./ V Tv L/W! x..!~,~.[~.~.j. Wo,2 ~ Wo,65 J Figure 3 - Dorsoplanites gr~cilis SPATH ; sample N2145/26, Figure 2 - Ontogenetic development of suture line in Eplvi~ Eastern slope of nearpolar Ural, r. Jatria, Volgian. gatites nikitini MICHAILOV ; sample Nll/4n Russian Platform, r. Volga, v. Kadhpir, Middle Volgian. The general outline of the ventral lobe remains secondary saddle is not reduced. It should be no- almost invariable in ontogeny and phylogeny. ted, that in all cases under discussion, the exist- Only a limited complication by secondary ele- ence of a six-lobate primary suture has no taxo- ments can be observed. The lateral lobe is almost nomic significance. always asymmetrically trifid with exception of some ; in adult Late Pla- It is worth mentioning that in some Macrocepha- centiceratidae in particular, this lobe is asymme- lites and Cadoceras the primary suture someti- trically bifid (Mikhailova 1983). The umbilical mes "sits astride" of the prosuture. At the same lobe which occurs last in Mezozoic ammonites is time the primary suture looks rudimentary - it is usually the smallest of all initial lobes, it occurs weakly divided. It consists of four lobes that always of the primary suture in a strictly definite strictly differ in size and configuration from each site, i.e. on the lobe and divides it into two equal other as well as from other initial suture lines. It parts. In the area of initial squeeze, as a result of must be noted that the ventral lobe remains un- narrowing of the whorl, the lobe is reduced and divided. looks often like a small hollow. Later on the um- bilical lobe gradually shifts to the margin of the There is a regular size variation of elements of shell. In most cases lobe U becomes trifid and the initial suture lines in ontogeny and in phylo- asymmetrical, though in some Olcostephanoidea geny. In particular, older elements are greater it is asymmetrically bifid (Figs. 2,3). (protolobes : V,L,D) in comparison with younger ones (metalobes : I and U). Lateral and inner No essential changes are observed in the evolu- saddles dominate over the saddles of the primary tion of the dorsal lobe ; the process of complica- suture. Equality between separate elements of tion of the dorsal lobe follows the common sche- suture line is preserved to a considerable extent me of various groups. At the beginning a pair of at later stages of evolution. marginal appendices occur and then other small 278

vl u UI 1 1! D I I

V1,V1 ('-'X L /-~U U',Ir~ll/~D ~ll

( W&7 WI,~;

2 I ,/ Figure 4 - Ontogenetic development of suture line in Kosmo. ceras jason (REINECKE) ; sample N100]/1, Russian Platform, Figure 5 - densicosta (QUENSTEDT) , sample r. Oka, v. Elatma, Middle Callovian. ND-14/1, Daghestan, v. Golotl, Lower . subsidiary elements are formed. At the same time, the lobe gradually narrows while being secondary lobe, that occurs on the top of the sad- elongated. With rare exceptions the base of the dle gets divided into two parts as a result of gra- dorsal lobe is always undivided. The internilater- dual deepening and differentiation of the lobes. al lobe, however, as well as the adjacent areas This phenomenon is better visible in the Late undergo essential changes in ontogeny and phylo- Cretaceous Placenticeratidae (Smith 1900 ; geny. Matsumoto 1953 ; Schindewolf 1966 ; Mirzoev 1967 ; Mikhailova 1967, 1978, 1983 ; Ilyin, In contrast the saddles have been disregarded in Mikhailova & Khakimov 1982). ontophylogenetic studies due to their conserva- tism ; but they evolved in different ways in dif- The most essential changes in phylogeny of su- ferent groups of Perisphinctina. In Perisphinctoi- ture line, however, take place within the lobe I dea and Olcostephanoidea as well as partly in and adjacent areas, as it was mentioned above. , saddles are mainly asymme- Judging by the ontogeny of Erycites fallifax ARK. trical, bifid and low. In Desmoceratoidea, L/U is (aider Schindewolf 1963, fig. 245), the complica- the highest saddle ; the mode of dissection of the tion of the suture line - in this most probably an- saddle I/D in representatives of , Sphae- cestral group of Perisphinctina - Hammatocerati- droceratidae, , Kosmoceratidae dae goes on in the following way. First, the lobe an Cardioceratidae deserves attention. It becomes U 1 occurs ventrallly of the lobe I near the saddle bifid already at early stages of ontogeny. At later U]I. Later, a new lobe I2 is generated at the base stages of growth two independent saddles are for- of the lobe I on the latteFs dorsal side. Later on, med instead of the initial saddle as a result of new elements of suture lobe appear as a result of deepening and widening of a secondary lobe dissection of the saddle U1/I1. It must be noted, (Figs. 1,4). Almost the same is true for the onto- that in most of the Mezozoic , inclu- geny of the saddle V/L in some Hoplitoidea. The ding Perisphinctina, lobes are formed in the area 279

U L~ U II D '

E/'~ ~ ,,I, , 1-, vlC' L FXu/ n' C1 r

"V, IV, . -g ~~/W0,8 ~ W0,25 ,J

Figure 6 - Pseudohaploceras douvillei (FALLOT); sample Figure 7 - Pseudosilesites seranoniformis EGOIAN ; sample N8(107/32) Daghestan, v. Tsudakhar, Lower Aptian. N8(404/9) Western Caucasus, r. Vulan, Upper Aptian.

of umbilical seam. Lobes I1 and I2, divided by a while following Mikhailova (1983, fig. 77-80), secondary narrow saddle elongate and grow nar- Grabovskaja (1984, fig. 1-3) and our own data rower. They become oblique without being isola- (Figs. 6-8) they are generated on the ventral side ted. In Perisphinctina heterotopy is observed in of the lobe I1, or at the latter's base. With regard the formation of U 1 : its site is oi~en displaced to the time of occurrence of the lobe U ~ in phylo- not only within the limits of our family, but also geny, a certain displacement towards earlier sta- within the limits of one and the same genus. For ges of evolution is observed. In particular, if in example, in Parkinsonia (Fig. 5 ; see also Schin- old representatives of the suborder Perisphincti- dewolf 1963 ; fig. 282-286) it is generated on the na U 1 appears to the end of the second lobe, or at saddle U/I. However, the limits for site displace- the beginning of the third whorl, in younger ment are not wide - from the top of the saddle samples U 1 is generated approximately in the U/I to the lower part of the ventral side of the middle of the second whorl. It must be noted lobe I. The place of generation of the lobe de- also, that the lobe U 1 is often originated on the pends upon the degree of involution of the shell, suture or behind the umbilical seam, during onto- i.e. which part of the lobe is located at the umbi- geny it shii~s to the lateral side and from this lical seam. It is noteworthy, that heterotopy of side it becomes part of the sutural lobe. No mat- the lobe U 1 sometimes seems to be the result of ter where the lobe has been formed in ontogeny - the authors ~ubjectivity, since various authors on the side or at the base of the lobe I - it always differently interpret the place of generation of de- must be designated by symbol U 1. Since in older finite element on one of the same taxonomic representatives of Perisphinctina and in the sup- group. For instance, according to Schindewolf posed ancestral group the Hammatoceratidae, it (1966, fig. 370-378 et al.) the lobe U 1 is generated occurs within the saddle U/I. on the top of the saddle U/I in Desmoceratoidea, 280

zVl J V1 ~ L U U1 l12/'x~ D,

F" L

VI--~L Uff! D. Wtl. W9,25 ~W1.2

Figure 9 - Choffatia kontkiewiczi SPATt{ ; sample N2144/1, ~ WO.6 Russian platform, r. Oka, v. Elatma, Middle Callovian.

(Fig. 9), Volgaites (Fig. 10), Erymnoceras (Fig. 11) and others. The same is also true of the family Figure 8 - Leymeriella terna SAVELIEV , sample N1309/1. Himalayitidae, i.e. the genera Corongoceras, Au- Western Kopet-Dag, Lower Albian. lacosphinctes, Micracanthoceras? (SCHINDEWOLF, 1966, fig. 327-330) with the difference that in the It may be concluded, that despite the variety in latter the inner branch of the lobe I-I2 and the ways of formation of the lobe U 1, the latter is secondary saddle I1/I2 are more developed, but at still conservative in the sense of morphological the same time they are less oblique. From the structure and further differentiation, therefore Oxfordian on, the trend of "slipping" of the site of being of no essential taxonomic significance. I2 to the base of the internilateral lobe is obser- ved during evolution of the lobe I in some pe- risphinctids, i.e. Properisphinctes, "Prososphinc- ATTEMPT OF SUTURE CLASSIFICA- tes", Perisphinctes (SCHINDEWOLF, 1966, fig. TION IN PERISPHINCTIDS 311,313-315) ; this leads finally to the almost asymmetric division of the lobe. At the same time Alterations, observed within the internilateral the inner branch of the internilateral lobe, I1, lobe and the adjacent saddle I/D are however, of and a newly formed secondary saddle evolved ra- the most taxonomic value for . ther intensely and in the adult, these elements According to Schindewolf (1963), asymmetrical acquire complete independence. However, the lo- division of lobes I-IlI2 takes place in Hammatoce- bes I1 and I2 are slightly oblique in most cases. ratidae. Later on both branches remain uncom- This trend is well pronounced in the ancestors, as plicated. They are located on the ventral side of it was mentioned above. The symmetric division the saddle I/D, being oriented obliquely. Almost of the internilateral lobe in the onto- and phylo- the same is true of the early Perisphinctina geny becomes a stable characteristic for the des- which are Bigotites, Zigzagiceras, "Pseudope- cendants. In Olcostephanoidea the lobe I is some- risphinctes" (SCHINDEWOLF, 1966, fig. 302, 303, times divided somewhat asymmetrically (Olcos- 305), Bajosisphinctes (Obsoletosphinctes), B. (Sie- tephanidae, Dorsoplanitidae, Ataxioceratidae), miradzkia), Leptosphinctes (Leptosphinctes) while in other cases it is divided symmetrically (BEZNOSOV & MIKHAILOVA, 1981, fig. 1,3,4) as (Berriasellidae, Craspeditidae). Symmetrical divi- well as Reineckia (SCHINDEWOLF, 1966, fig. 338), sion becomes more typical of Desmoceratoidea Collotia (SCHINDEWOLF, 1966, fig. 340), Choffatia and Hoplitoidea. It must be noted also, that in 281

V 'V1 ~_ L r,t~U_ U1 I r~Dt W5,5 7 ~~,5 W4J

v~v~ L U UI, I2 D

W 2 2 .,/ fw. ''~

Figure 10 - Volgaites elatmaensi8 SASONOV ; sample N2144/4, Russian Platform, v. Elatma, Middle Callovian. older perisphinctid U ] is often generated before Figure 11 - Eryrnnocero& doUfo~ (ROMAN) ; sample N20/56-1, Northern Caucasus, r. Cherek Balkarski, Middle I2, while in younger representatives this is not Callovian. the case, and the division of the lobe I precedes the occurence of U 1. asymmetrically on both sides of the lobe I either simultaneously or at different times. On the ven- Subsequently, in spite of the early division, the tral side of the lobe I and near its base, the lobe dorsal branch evolves more intensely in compari- U occurs ; while on the dorsal side and near the son with the ventral one. The former replaces the top of the saddle, I2 is generated (Fig. 12). Al- internilateral lobe becoming completely isolated. most the same is true of Parkinsoniidae (Fig. 5) All elements of the suture line are placed on a and Morphoceratidae (Schindewolf 1965, fig. 297- straight line. A sutural lobe is formed as a result 299). Here, new elements are first generated on of dissection of the saddle UI/I1. the ventral side of the lobe I. Later on, the lobe I2 develops at the top of the saddle I/D, and Representatives of Desmoceratoidea and Hoplitoi- dea are practically undistinguishable from Olcos- abruptly descends deepening. It becomes larger tephanoidea in mode of the early differentiation than the lobe I1. Both branches (Ili2) are directed of the suture line. The lobe I is almost s~n. metri- obliquely. It must be noted, that in one of relati- cally divided, while, later on, the lobe U is gene- vely young representatives of Stephanoceratidae rated. Subsequently, the branches of the interni- (i.e. Polyplectites) a new element originates closer lateral lobe become isolated, the dorsal one is to the top of the saddle IfD (Schindewolf connected with the lobe D, while the ventral one 1965,fig.258,259). Later I2 on it deepens, becomes shifts to the umbilical seam. A sutural lobe is ge- isolated and straightens. If trace the way of evo- nerated as a result of dissection of the ventral lution of the given lobe in phylogeny it may be side of the ventral branch (Figs. 6,7). noted that unlike Hammatoceratidae and early Perisphinctoidea, here the place of its generation A different way of suture development is repre- shifts up to the inner side of the lobe I manifes- sented in Stephanoceratidae, Morphoceratidae as ting tendency to isolation and straightening. The well as in Parkinsoniidae. In particular, in same is observed in other, genetically quite re- Stephanoceratidae new elements are generated mote groups of ammonites (Aptian Chelonicerati- 282

lobe shifts along the dorsal side of the lobe, thus Vl~ j ~ L ~j~U ~D leading to an asymmetric subdivision. ! 12 U I I1 Hammatoceratidae, early representatives of Pe- risphinctoidea and the families mentioned above, do not differ essentially in the general scheme of development of the suture line. We consider the lobe developing on the d~rsal side of the lobe I as homologue of the lobe U , while the lobe origina- ting in the top of the saddle I/D as homologue of the lobe I2. Consequently, they must be designa- ted by corresponding symbols. The whole group of ammonites comprising Sphaeroceratidae, Macrocephalitidae, Cardiocera- tidae, Otoitidae and Kosmoceratidae is consider- ably different in the evolution of the dorsal part of suture line. In ancestral representatives such as Otoitidae and Sphaeroceratidae, a new lobe is originated on the side of dorsal lobe. During onto- L and phylogeny it gradually shifts to the top of the saddle I/D. At the same time the lobe deepens. It becomes independent and then replaces the lobe I. According to Schindewolf (1965) as well as pro- ceeding from our data this phenomenon is well pronounced in the phylogenetic sequence ; Otoiti- dae -~ Sphaeroceratidae -~ Macrocephalitidae -~ Kosmoceratidae -~ Cardioceratidae. An interes- ting pattern is observed in representatives of the family Macrocephalitidae having an intermediate Figure 12 - Stephanoceras sp., sample N589, localities position in this sequence. At an early stag~ of on- unknown, Upper . togeny of some species (Fig. 1), the lobe P is ge- nerated symmetrically on the top of the saddle I/D ; in other ones, the same lobe asymmetrically is dividing this saddle (Fig. 13). According to Thierry (1975, 1978), a similar pattern is obser- ved in other , as wel~. In our opi- nion, the heterotopy of the lobe F may, thus serve for evidence of generic relations between Macrocephalitidae and Sphaeroceratidae as well as between Macrocephalitidae and Cardiocerati- dae.

The lobe U 1 often develops on the ventral side of Figure 13 - Suture lines of Macrocephalites cf. canizarroi (GEMMELLARO) ; sample N420/58-2, Northern Caucasus, pass the lobe I, closer to its base. Two cases of devia- C-erchoch, Lower Callovian. tion from the above described normal evolution of suture line are observed. In the first case, in some representatives of Otoitidae, particularly in dae and Acanthohoplitidae) as well. In Acantho- Otoites and Emileia (Schindewolf 1965, figs. 246, hoplitidae, the new element occurs on the ventral 250) an asymmetric division of the internilateral side of the internilateral lobe and near the top of lobe IlI2 takes place after formation of U l and I 1 the saddle U/I, while in the probably ancestral like in Hammatoceratidae and Perisphinctidae. Cheloniceratidae the element is generated sligh- We consider this a base for suggesting phyletic tly lower, in the middle of the ventral side or relations between Hammatoceratidae and Otoiti- near the base of the lobe I. Heterotopy of new dae. Heterotopy in the formation of lobe U 1 is elements is observed within the lateral lobe, as also oberved in re]presentatives of Kosmocerati- well. Thus in older Cheloniceratidae the lateral dea. Sometimes U is generated on the ventral lobe is divided almost symmetrically, while in side of the internilateral lobe, near its base (Fig. younger ones the place of generation of the new 4), or higher up the side, near the top of the sad- 283

Figure 14 - Different tylms of suture line on- togeny in Perisphincti- no, a, Hamraatocerati- dal (Eryeite. faUifax ARKELLI (aller Schinde~ wolf 1965, fig. 245) ; b, \ Stephanoceratoidal (Stephanocer~s sp.) ; c, Perisphinct~idal (Inz- phinctez nikitinoen- f uis SASOI~OV) ; d, Car- diocetoidal (Macro- cephalites nikitini MICHAILOV) ; f, Desmo- ceratoidal (Melchiori- tes emcrici (RAsp.) ; g, Hoplitoida[ (Cleoniras dubium MIc~Lo & 2~RECHOV^ (atter Mi- chailova 1983, fi R. 89).

e

n, \ / b

dle U/I (Schindewolf 1965, figs. 271-273). In cer- This similarity is manifested primarily by the si- tain cases it is generated at the base of the lobe milar position of the new lobe. This similar posi- I, thus resulting in an almost symmetrical divi- tioning is, however, since these lobes are not ho- sion of the latter. However, in our opinion, whe- mologues, as was mentioned above. rever the U lobe is generated - either at the base of the lobe I or at the top of the saddle U/I, it is A few words about some other regularities of su- always located at the umbilical seam and most ture line development in Perisphinctina : most of likely it is a homologue of the lobe U 1 in Hamma- the representatives of the suborder perisphincti- toceratidae, as it was mentioned above. na are characterized by a suture line with a me- dium degree of differentiation. At the same time It must be noted, that adult suture line of the a progressive evolution of the suture line is ob- considered ammonite groups bear a certain re- served in phylogeny. This particularly manifested semblance with some representatives of Olcos- by the early occurence of new elements in the tephanoidea, Desmoceratoidea and Hoplitoidea. onto- and phylogeny of young representatives of 284

Perisphinctina, by the increase in number of ele- ments as well as the rise of differentiation de- 5TAGE.S Pe r' z:, ,r p h z: n c ~ z: n a gree. In general, it may be concluded that the more complex the suture line is, the better pro- nounced is the symmetry of it's individual ele- ~mpanian ,=., ments. In this respect Perisphinctidae (Figs. 9, 10), or Parkinsoniidae (Fig. 5) may be compared with (Figs. 6,7). On the other hand, in some phylogenetic branches a reverse if,,Tupontan ~-~ picture is observed : the suture line becomes sim- plified possibly related to specialization, when sculpture coarsens, degree of involution decreases .,~lbian and whorls width become in comparison with the apiz~ ancestors. This may be exemplified by repre- Ba~.~tan sentatives of the family Leymeriellidae (Fig. 8) in wich suture line is markedly simplified as compa- red with ancestral forms (e.g. Pseudosilesites, Fig. ~ Valaz2iz~a,~ 7). The same is true of same representatives for Himalayitidae, Kosmoceratidae and Polyptychiti- dae, which suture line is weakly differenciated in I~,/honl~zn ~ comparison with their ancestors. ~

CONCLUSIONS

In Perisphinctids the prosuture is threelobate, while the primary suture is four-, five-or sixlo- Bajoczan bate. A fourlobate primary suture is rarely obser- gaLen,an "~~ l ved when it "sits astride" of the prosuture. Five- lobate primary sutures occur in most Perisphinc- tina. Sixlobate primary sutures are observed in some Placenticeratidae (VLUIII1D) and Macro- Figure 15 - Perisphfilctid phylogeny assuming a hammatoce- cephalitidae (VLU1UIID). In the latter however, ratid origin. the line soon becomes fivelobate as result of re- duction of the secondary saddle U1/U1, while in dioceratoidea, Olcostephanoidea, Desmoceratoi- the Placenticeratidae IlI1 evolve subsequently in dea and Hoplitoidea), next to the dorsal lobe oc- ontogeny. Existence of fouror sixlobate primary curs an isolated, straight-forward and rather well sutures has no taxonomic value. differenciated lobe and replaces the internilateral lobe. The formation of various morphogical types In the differentiation process of the internilateral of suture lines seems to correlate to intercameral lobe and adjacent saddles an acceleration effect is hydrostatic pressure as well as to the absolute noticeable, when new elements progressively oc- size of the involute part of the shell. cur in early stages of ontogenetic evolution. The occurence of the sixth element in the primary su- In ontogeny a series of new small elements oc- ture of some Late Cretaceous Placenticeratidae curs in the area of the umbilical seam often for- may be considered as a result of such an accele- ration. ming a sutural lobe. The latter is built as a re- sult of dissection of the initial outer side of the Heter~topy is pronounced in the formation of lo- lobe I. bes U , I2 and I z in onto- and phylogeny. Evolution of the ventral part of the suture line Based in the morphology of the dorsal parts of follows the common scheme nearly in all repre- the suture line two general types of differentia- sentatives of Perisphinctina. In this respect the tion may be distinguished. In one group (Pe- mode of early differentiation of the inner part of risphinctoidea, Stephanoceratoidea an analogue the suture line acquires special taxonomic signifi- of the true internilateral lobe is absent. The cance for this suborder. Most attention should be branches of the initial lobe I are relatively unde- paid to the dissection of the lobe I and saddle I/D. veloped. They are not isolated, being arranged The following types of suture lines may be distin- obliquely. In the other group of ammonites (Car- guished with in Perisphinctina (Fig. 14) : 285

- Perisphinctoidal type (Fig. 14c), with asymme- chyceratidae Buckman 1918 ; ? Himalayitidae tric division of internilateral lobe (IlI2) these Spath 1925] ; f) Superfamily Olcostephanoidea branches are not isolated being oriented obliquely Pavlow 1892 [Families Olcostephanidae Pavlow in the adult stage ; 1892 ; Craspeditidae Spath 1924 ; Berrisellidae Stephanoceratoidal type (Fig. 14b), with oc- Spath 1922 ; Ataxioceratidae Buckman 1921 ; curence of a new lobe I2 near the top of the sad- Dorsoplanitidae Arkell, 1950 ; Polyptychitidae dle I/D on dorsal side of the lobe I and with it's Spath 1924 ; Aulacostephanidae Spath 1924 ; As- subsequent descending ; pidoceratidae Zittel 1895 ; ? Oosterellidae Breis- - Olcostephanoidal type (Fig. 14e), with symme- troffer 1940 ; ? Simoceratidae Spath 1924]. tric (IlI1) or asymmetric (I211) division of the lobe I; Acknowledgement - Cordial thanks are due to J. - Desmoceratoidal type (Fig. 14f), with symmetric Wiodmann (Tfibigen) for contructive criticism and for division of the internilateral lobe (IlI1) and with linguistic corrections. formation of a sagging sutural lobe ; - Hoplitoidal type (Fig. 14g), with early symme- tric division of the lobe I, in most cases with for- REFERENCES mation of a linear sutural lobe as well as of an adventive lobe ; ALEKSEEV S.N. 1982 - Razvitie lopastnikh linii v onto- - Cardioceratoidal type (Fig. 14d), with the for- geneze nekotorikh pozdnejurskikh i rannemelovikh mation of an individual lobe on top the saddle Craspeditidae i polyptychitidae. Stratigraphie tria- I/D. sovikh i jurskikh otlozhenii neftegazonosnikh bassei- nov SSSR : 115-128. The desmoceratoidal type is the most conserva- BEZNOSOV N.V. 1960 - K systematike jurskikh Ammo- noidea. Paleont. Zhurnal, 1 : 47-60. tive. This type of suture line turns out to be the BEZNOSOV N.V. & MIKIIAILOVAI.A. 1981 - Systematika most viable and lasting. It was functioning du- srednejurskikh Leptosfmctin i Zigzagiceratin. Pa- ring the whole Cretaceous period. leont. Zhurnal, 3 : 47-60. GRABOVSK~JA V.S. 1984 - Ontogenez lopastnoi linii Proceeding from data on the morphogeny of the pozdnemelovikh desmoceratacei Sakhalina. Syste- shell, three phylogenetic lines may be draw in tika i evolucia bespozvonochnikh Dalnego Vostoka : Perisphinctina. These are : I. Hammatoceratidea 94-99. Perisphinctoidea Olcostephanoidea ~ Desmo- ILYIN V.D., MIKHAILOVAI.A. & KHAKIMOVF.Fh. 1982 - ceratoidea --~ Hoplitoidea ; II. Hammatoceratidae Morfogenez senomanskikh Placenticeratid. - Dokla- -~ Stephanoceratoidea ; HI. Hammatoceratidea dy AN SSSR, 266, 2 : 474-477. KmVOSCHAPKINA V.S. 1978 - Ontogenez lopastnoi linii -~ Cardioceratoidea (Fig. 15). pozdnemelovikh tetragonitid Sakhalina. Paleont. Zhurnal, 1 : 69-77. The suborder Perisphinctina includes the follo- KULLMANN J. & WIEDMANN J. 1970 - Significance of wing suporfamilies a) Superfamily Stephanocera- sutures in phylogeny of Ammonoidea. Paleontol. toidea Neumayr 1875 [Families Stephanocerati- Contrib. Univ. Kansas, 47 : 1-32. dae Neumayr 1875 ; Morphoceratidae Hyatt KVANTALIANI I.V. 1989 - Early cretaceous ammonites 1900; Parkinsoniidae Buckman 1920 ; ? Tulididae of the Crimea and Caucasus and their biostratigra- Buckman 1921 ; ? Oecoptychiidae Arkell 1957] ; phic significance. Mezniereba : 228 p. b) Superfamily Cardioceratoidea Siemiradzki MATSUMOTO T. 1953 - On the ontogeny Metapla- centi- 1891 [Families Otoitidae Mascke 1907 ; Sphaero- ceras subtilistriatum (JIMNO). Jap. J. Geol. Geogr., 23 : 139-150. ceratidae Buckman 1920 ; Cardioceratidae Siemi- MIRZOEV G.G. 1967 - O vzaimootnoshenii semeistv radzri 1891 ; macrocephalitidae Buckman 1922 ; Hoplitidae i placenticeratidae. Paleontol. Zhurnal, Mayaitidae Spath 1928 ; ? Kosmoceratidae Haug 4 : 56-70. 1887] ; c) Superfamily Desmoceratoidea Zittel MIKHAILOVA I.A. 1974 Sviazi rannemelovikh i 1895 [Families Desmoceratidae Zittel 1895 ; Hol- pozdnemelovikh goplitacii. Spisanie na Bolgarskogo codiscidae Spath 1924 ; Hyat 1900 ; geol. druzhestvo., 35, 2 : 117-132. Kosmoceratidae Spath 1922 ; Pachiscidae Spath MIKHAILOVA I.A. 1977 - O schestilopastnoi primasu- 1922 ; Muniericeratidae Wright 1952 ; Leymeriel- ture melovikh ammonitov. Doklady. AN SSSR, 234, lidae Breistroffer 1951] ; d) Superfamfly Hoplitoi- 5 : 213-216. dea H. Douvilld 1890 [Families Hoplitidae H. MIKHAILOVA I.A. 1978 - Osobennosti morfogeneza se- meistva Placenticeratidae Hyatt. Doklady AN Douvilld 1890 ; Placenticeratidae Hyatt 1900 ; SSSR, 242, 1 : 207-210. (Schloenbachiidae Parona & Bonarelli 1897 ; ? MIKHAILOVAI.A. 1979 - ontogeneticheskoe razvitie ne- Trochleiceratidae Beistroffer 1953 ; ? Engonocera- kotorikh pozdnemeovikh tetragonitid. Vestnik tidae Hyatt 1900] ; e) Superfamily Perisphincti- MGU, 4, geologia, 1 : 23-34. doidea Steinmann 1890 [Families Perisphinctidae MIKHAILOVA I.A. 1983 - Systema i filogenia melovikh Steinmann 1890 ; Reineckiidae Hyatt 1900 ; Pa- ammonoidei. Nauka : 280 p. 286

SHAR1KADZE M.Z. 1984 - O schestilopastonoi primasu- SMml J.P. 1900 - The development and phylogeny of ture rannemelovikh tetragonitid (Ammonoidea). . Proc. Cal. Acad. Sci., 3, 1, 7 : 181- Doklady ANN SSSR, 275, 5 : 1182-1184. 240. SCHINDEWOLF O.H. 1963 - Studien zur Stammesges- THIERRY J. 1975 - Ontogeneze de la ligne de suture et chichte der Ammoniten. Lief. 3. Abhandl. Akad. origine des Mayaitidae Spath, 1928 (, Wiss. und Lit. Mainz, math.-natur. K/., 6 : 261-406. Stephanocerataceae) de l'Oxfordien moyen de la SCHINDEWOLF O.I-I. 1965 - Studien zur Stammesges- province Indo-Malgache. C. R. Acad. Sci. Paris (D), chichte der Ammoniten. Lief. 4. Abhandl. Akad. 280 : 1543-1546. Wiss. und Lit. Mainz, rnath..natur. K/., 3 : 411-508. THIERRY J. 1978 - Le genre Macrocephalites du Callo- SCHINDEWOLF O.S. 1966 - Studien zur Stammesges- vien inf~rieur (Ammonites, Jurassique moyen). chichte der Ammoniten. Lief. 5. Abhandl. Akad. M~m. Gdol. Univ. Dijon, 4 : 490 p. Wiss. und Lit. Mainz, math.-natur. K/., 3 : 511-640. WESTERMANN G. 1956 - Phylogenie der Stephanocera- SCHINDEWOLF O.H. 1968 - Studien zur Stammesges- taceae und Perisphinctaceae des Doffer. Neues Jb. chichte der Ammoniten. Lief. 7. Abhandl. Akad. Geol. Paliiontol., 103, 1/2 : 233-270. Wiss. und Lit. Mainz, rnath.-natur. K/., 3 : 731-901. WIEDMANN J • KULLMANN J. 1981 - Ammonoid sutu- SttEVlR~V A.A. 1960 - Ontogeneticheskoe razvitie ne- res in ontogeny and Phylogeny. In M.R. House & kotorikh verkhnejurskikh ammonitov. Bjull. MOIP, J.R. SENIOt~ (eds.) : The Ammonoidea. N.Y.. Acad. otd. geologicheski, 35 : 69-78. Press, Systematics Assoc., Spec. Vol. 18 : 215-255. SHULGINA N.I. 1985 - Borealnie basseini na rubezhe juri i mela. Nauka : 162 p.