Permian Ammonoids of the Kolyma–Omolon Region: Ogonerian Association 2013

ISSN 0031�0301, Paleontological Journal, 2013, Vol. 47, No. 1, pp. 1–10. © Pleiades Publishing, Ltd., 2013.Original Russian Text © R.V. Kutygin, V.G. Ganelin, 2013, published in Paleontologicheskii Zhurnal, 2013, No. 1, pp. 3–10.

1

INTRODUCTION

Previously we discussed the earliest Permianammonoids of the Kolyma–Omolon Region found inthe middle part of the Munugudzhakian Formation ofthe Munugudzhak River recognized as the KyrianAssemblage and tentatively dated Early Sakmarian(Kutygin and Ganelin, 2011). In 1977, V.G. Ganelincollected large ammonoid material in the same sectionin the upper portion of the Munugudzhakian Forma�tion (Samples 11–3/VG–77 and 11–4/VG–77), pro�visionally identified by M.F. Bogoslovskaya as Uralo�ceras aff. fedorowi Karpinsky and Neoshumardites tri�ceps Ruzhencev (Ganelin, 1984). These identificationallowed attribution of the host rocks to the LowerArtinskian Substage. Later specimens of “Uralocerasaff. fedorowi” from Munugudzhak were described asnew species of Uraloceras (U. omolonense and U. koly�mense), which based on “all morphological criteriawere more closely related to the Sakmarian U. simensefrom the Urals” (Bogoslovskaya and Boiko, 2002,p. 34). Nevertheless, the Munugudzhak species wereattributed to the later (Aktastynian) stage in the evolu�tion of Uraloceras, based on their association with theEarly Artinskian Neoshumardites triceps. Therefore,the stratigraphic range of the ammonoid associationunder consideration was thought to correspond to themiddle part of the Echian Horizon of the WesternVerkhoyansk Region, with the beds with Eotumaro�ceras endybalense (Kutygin et al., 2002) in the LowerArtinskian Substage. However the Munugudzhakspecimens of Uraloceras were considered to be themost similar to U. subsimense, which characterizes theArkachan ammonoid association (beds with U. subsi�

mense) of the Upper Sakmarian Substage of theVerkhoyansk Region (Kutygin, 2004, 2006), and con�sequently dated Late Sakmarian. The discovery ofU. omolonense in the lower portion of the EchianHorizon of the western Verkhoyansk Region becamean important argument in this correlation, as thisinterval was assigned to the Upper Sakmarian (Kuty�gin et al., 2010). The resulting conflict in correlationof the Sakmarian–Artinskian boundary beds of theVerkhoyansk�Okhotsk and Kolyma–Omolon regionsrequired the reexamination of the entire collection ofMunugudzhak ammonoids, which we assigned to theOgonerian association (based on the name of theOgonerian Horizon).

Almost all specimens in the collection are stronglydistorted, which considerably complicated the study.The collection is dominated by U. omolonense Bog�oslovskaya et Boiko, which is characterized by a mod�erately narrow shell with a relatively simple suture.This species, similar to the stratigraphically earlierKyrian U. margaritae apparently belongs to the U. sim�ense group that unites moderately involute weaklyornamented shells with relatively narrow ventralprongs. While comparing U. omolonense with U. sim�ense, it should be noted that the former species hasmore derived morphological characters (fine orna�mentation of the internal whorls and larger shell). Itshould be noted that U. omolonense is morphologicallysimilar to U. newadense (Schiappa et al., 2005). Somespecimens of the North American species are identicalto U. omolonense in their shell shape. The differencesbetween the species are subtle and are primarily man�ifested in the ornamentation: in juveniles of U. omolo�

Permian Ammonoids of the Kolyma–Omolon Region: Ogonerian AssociationR. V. Kutygina and V. G. Ganelinb

aInstitute of Diamond and Precious Metals Geology, Siberian Branch, Russian Academy of Sciencese�mail: [email protected]

bGeological Institute, Russian Academy of Sciences, Pyzhevskii per. 7, Moscow, 109017 Russiae�mail: [email protected]; [email protected]

Received November 28, 2011

Abstract—The Ogonerian association of Early Permian ammonoids from the Upper part of the Munu�gudzhakian Formation (upper part of the Ogonerian Horizon) contains Uraloceras omolonense Bogoslovskayaet Boiko, U. kolymense Bogoslovskaya et Boiko, Neoshumardites munugudzhensis sp. nov., N.? nassichuki sp.nov., and Bulunites gracilis sp. nov. These taxa suggest the Sakmarian–Artinskian boundary beds examined aregeochronologically older than the level with Neoshumardites triceps Ruzhencev in the South Ural Mountains.

Keywords: Ammonoids, Permian, Kolyma–Omolon Region

DOI: 10.1134/S003103011301005X

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PALEONTOLOGICAL JOURNAL Vol. 47 No. 1 2013

KUTYGIN, GANELIN

nense riblets are more strongly rectiradiate, whereasconstrictions are shallower and weakly bent. It is note�worthy that in the large sample of U. newadense(200 specimens) (Schiappa et al., 2005), the largestshells were only up to 30 mm in diameter, which canalso be considered as a differentiating character. How�ever, we do not exclude the possibility of close rela�tionship between these two species. The Late Sakmar�ian (Pre�triceps) age of U. omolonense is suggested byits occurrence in the lower part of the Echian Horizonin the lower reaches of the Delendzha River in the west�ern Verkhoyansk Region, 56 m downstream of theoccurrence of Neoshumardites hyperboreus Ruzhencev.The latter species is morphologically similar to N. tri�ceps and is probably of a similar age (Kutygin et al.,2010).

Another Ogonerian species of Uraloceras U. koly�mense, is identical to U. subsimense in its shell shapeand is widely distributed in the Sakmarian of theVerkhoyansk Region. Apparently these two species areclosely related and can probably be considered to beconspecific. Based on the previous interpretations ofthe early evolution of the genus Uraloceras (Kutyginand Ganelin, 2011), it could be suggested that theOgonerian species terminated the evolution of the lin�eage Paragastrioceras sterlitamakense → Uralocerasmargaritae → U. simense → U. omolonense. This wasaccompanied by weakening of the ribs and increase inthe longitudinal ornamentation, reduction of theheight of the ventral projection of the transverse orna�mentation and smoothening of constriction on thebody chamber. The ribs were becoming more denselyspaced. However, because U. margaritae and U. omolo�nense were only found in northeastern Russia, whereasParagastrioceras sterlitamakense and Uraloceras sim�ense are restricted to the South Urals, the above phy�logenetic reconstructions are provisional. The mor�phogenetic evolution and intraspecific variability ofthe species U. simense are key issues in understandingthe evolution of this group of the Uraloceras species.When establishing this species, Ruzhencev (1951)described a collection from the Tastubian (18 speci�mens) and Sterlitamakian (2 specimens) horizons.Unfortunately, the author of the species did not indi�cate whether or not there were any differences betweenthe Tastubian and Sterlitamakian specimens of thisspecies. Similarly he did not discuss the intraspecificvariability of U. simense. The collection in the Paleon�tological Institute of the Russian Academy of Sciencecontains only two very different specimens. It isunclear whether they belong to different species orrepresent polar varieties of a continuous morphologi�cal lineage. Therefore it is necessary to re�examine allthe preserved material of U. simense. It is possible thatthe existing collections contain specimens similar toeither U. margaritae and U. omolonense or both.

The examined sample of the Ogonerianammonoids contains as few shells with biconvex trans�verse ornamentation. The entire external surface of

the adult whorls of these unusual specimens possessesdelicate crescentic riblets/folds. Similar ornamenta�tion was observed in the genus Bulunites. A closerexamination of the Ogonerian ribbed specimensshowed another feature of this genus, i.e., symmetrical(helmet�like) shape of the lateral lobe. All this allowedthe assignment of the specimens under discussion tothe genus Bulunites, namely in the new species B. gra�cilis sp. nov. The taxonomy of the genus Bulunites isstill debatable. At present, there are two major viewson the taxonomy of this genus. According to one inter�pretation, Bulunites represented the terminal stage inthe evolution of the endemic, mainly Carboniferousfamily Orulganitidae (Andrianov, 1985, Kutygin et al.,2002). The appearance of this orulganitid genusmarked the cessation of a triangular�spheroconic stageand a cadiconic stage in the ontogeny of juveniles. Inthis case the observed essential morphological differ�ences distinguish this species from the youngest mem�ber of the Carboniferous Orulganitidae (genus Yaku�toglaphyrites), which could only be explained by thepresence of a large paleontological hiatus embracingthe entire Gzhelian Stage. Bulunites has been consid�ered to be one of the early members of the large EarlyPermian family Paragastrioceratidae (Leonova, 2002;Boiko, 2010). We cannot accept this interpretationbecause Bulunites has biconvex ornamentation, whichdistinguishes it from paragastrioceratids. It would bemore logical to assign Bulunites to the closely relatedfamily Pseudogastrioceratidae and consider it to beclosely related to the genus Stenolobulites (Mikesh,Glenister, and Furnish, 1988). To solve the problem ofthe taxonomic assignment of the genus Bulunites,detailed ontogenetic and morphogenetic examina�tions are necessary along with a revision of all availableBulunites material and comparative analysis involvinggeochronologically younger orulgantitids and earlyparagastrioceratids. Until such studies are preformed,we accept Andrianov’s (1985) view and considerBulunites within the endemic family Orulganitidae.Members of Bulunites (B. mezhvilki Andrianov) werepreviously known only from the Asselian�Lower Sak�marian beds in the Verkhoyansk Region (Andrianov,1985; Kutygin, 2004). Judging from the more closelyspaced riblets and more derived suture, the Ogonerianspecies of the genus (B. gracilis) is a more advancetaxon. This suggest that B. gracilis is more likely LateSakmarian, rather than Asselian�early Sakmarian

We particularly focused on the three specimens thatwere previously identified as Neoshumardites triceps(Ganelin, 1984), because these specimens were thebasis for the Early Artinskian age of the host rocks.One of the important taxonomic characters of thegenus Neoshumardites is the presence of fine transverseornamentation with no sign of spirals. In Ruzhencev’s(1956) opinion, spiral ornamentation disappearedwhen Neoshumardites branched off from “Preshu�mardites” (=Andrianovia) (at the beginning of theArtinskian). No transverse or spiral ornamentation


PERMIAN AMMONOIDS OF THE KOLYMA–OMOLON REGION 3

was observed on the shells of the Ogonerian specimensof Neoshumardites. However, the surface of the shellpossesses a pattern composed of irregular papillae.Morphogenetically, this papillate ornamentation pos�sibly characterizes the stage of the cessation of spiralprior to the appearance of typical Neoshumardites withtransverse ornamentation. It is essential to mention anextremely primitive shape of the ventral lobe of onespecimen which we assign to the new species Neoshu�mardites? nassichuki sp. nov. Very narrow ventralprongs and changes in the shape of the lateral lobe inontogeny (from distinctly trifid to V�shaped) are char�acteristic feature of Andrianovia. If the ornamentationwas not taken into account, this specimen could beassigned to the genus Andrianovia. The second speci�men has a sutural outline usual of the typical Neoshu�mardites, but the inner lateral and dorsal lobes are tri�fid, which has not been indicated for Neoshumardites,but is typical of the geochronologically older somohol�itids (Andrianovia). The surface of the phragmoconeof this specimen assigned to a new species Neoshu�mardites munugudzhensis sp. nov., is covered by apapillate pattern, as in N.? nassichuki. Because of there�identification of Neoshumardites, which was thebasis for dating the ammonoid association under con�sideration, the age has to be reassessed. As for the geo�chronologically older (Kyrian) association, ammonoidsof the upper part of the Munugudzhakian Formation donot include species allowing a direct correlation withSouth Uralian sections. Neoshumardites was assignedto a new species, unknown outside the type region. Itsage only can be judged based on the level of the evolu�tion of their main characters in the light of theaccepted phylogenetic interpretation of somoholitids(Boardman et al., 1994; Leonova, 2002). The origin ofNeoshumardites from the Sakmarian genus Andri�anovia is supported by the presence of archaic ele�ments of the suture inherited from Andrianovia (shapeof the ventral and lateral lobes in Neoshumardites? nas�sichuki and both internal lobes in N. munugudzhensis),uncharacteristic of N. triceps that appears in the SouthUralian sections at the base of the Artinskian. Thissuggests that the Ogonerian representatives Neoshu�mardites are geochronologically older than the SouthUralian N. triceps.

The above discussion suggests that the Ogonerianammonoid association can be dated as “pre�triceps”and characterizes the Sakmarian�Early Artinskianboundary interval. In the opinion of R.V. Kutygin, thestratigraphic range of this association is restricted tothe upper part of the Upper Sakmarian. This datingdisrupts the generally accepted view that the genusNeoshumardites was restricted to the Aktastynian(Artinskian Stage) (Ruzhencev, 1956; Ruzhencev andBogoslovskaya, 1978). However, archaic features ofthe sutural outline known in the Ogonerian Neoshu�mardites suggests that the Early Artinskian speciesN. triceps was not initial in the evolution of the genus,hence Neoshumardites first appeared before the Sak�

marian–Artinskian boundary. V.G. Ganelin maintainsa slightly different view. In Ganelin’s opinion, itshould be remembered that Ruzhencev, who proposedthe ammonoid characterization of the Artinskian, hadbased it on the concept of a bichronotype of the zonaland stage subdivisions (Ruzhencev, 1975, 1977). Fromthis point of view, the appearance of the genus Neoshu�mardites suggests that host rocks should belong to theArtinskian Stage. It would be more correct to comparethe succession under discussion with the stratotype,but the stratotype section of this stage does not containammonoids. In this situation, in Ganelin’s opinion,the host rocks should be referred to the Sakmarian–Artinskian boundary interval.

MATERIAL

The material is to be housed in the Borissiak Pale�ontological Institute of the Russian Academy of Sci�ences, Moscow (PIN) collection no. 1802.

SYSTEMATIC PALEONTOLOGY

Order Goniatitida

S u p e r f a m i l y Somoholitoidea Ruzhencev, 1938

Family Somoholitidae Ruzhencev, 1938

Genus Neoshumardites Ruzhencev, 1936

Neoshumardites munugudzhensis Kutygin et Ganelin, sp. nov.

Plate 1, figs. 1 and 2

E t y m o l o g y. From the Munugudzhak River.H o l o t y p e. PIN, no.1802/41; Omolon Massif,

Munugudzhak River; upper part of the Munu�gudzhakian Formation, Sakmarian–Artinskian bound�ary beds, supposedly Upper Sakmarian Substage.

S h e l l s h a p e. (Fig. 1e). The shell is large, evo�lute, moderately wide (transitional between theparagiconic and metaliconic according to Kutygin’s(1998) classification), with a semi�elliptical whorlcross�section. The umbilical wall is narrow, slightlyflattened, and relatively steep. The umbilicus isstepped, medium�sized to moderately wide. Theumbilical shoulder is relatively sharp. In medium�sized specimens the shell is wider with a moderatelynarrow to medium�sized umbilicus, subtriangularwhorl cross�section, and slightly angular ventralshoulder.

D i m e n s i o n s i n m m a n d r a t i o s i n %:

Specimen PIN, no. Dm WW WH UW WW/

DmWH/Dm

UW/Dm

WW/WH

Holotype 1802/41

70.0 40.0 23.0 28.0 57.1 32.9 40.0 173.9

43.5 28.5 16.5 13.5 65.5 37.9 31.0 172.7

35.0 25.5 14.5 10 72.9 41.4 28.6 175.9

20.5 16.0 8.5 6.2 78.0 41.5 30.2 188.2

15.5 11.8 6.6 – 76.1 42.6 – 178.8

4


KUTYGIN, GANELIN

O r n a m e n t a t i o n. (Fig. 1d). The shell haswide, moderately deep constrictions (3 or 4 perwhorl). It has a wide and deep ventral sinus and shal�low and narrow umbilical sinus. The shell matrix ispreserved only on the flanks at Dm about 25 mm. Inthis region, the shell is covered with very small tuber�cles (papillae), more than 20 per mm2, which areevenly distributed on the surface. The papillae are iso�metric, rounded, flattened, less than 0.1 mm wide.Such papillate ornamentation has not previously beenrecorded in somoholitids.

S u t u r e. (Figs. 1a–1c; 2e). Only the external por�tion of the suture was studied on the last whorl. Theventral lobe (V1V1) is composed of two wide lanceolateprongs with convex sides and deep, mamillate termi�nations. The median saddle is wide and moderatelyhigh. The first lateral saddle is high and asymmetrical,slightly angular at the top and constricted in the mid�dle. The lateral lobe L is considerably deeper than theventral lobe, has a long and wide central digit and

prominent lateral shoulders. The second lateral saddleis asymmetrical, slightly angular at the top. The umbil�ical lobe U is funnel�shaped with a deep, moderatelynarrow middle digit. The inner portion of the suture isstudied for the medium�sized phragmocones. Thedorsal and inner lateral lobes are distinctly trifid, withvery long, narrow central digits and well developed lat�eral digits. At earlier ontogenetic stages (Dm from 10to 25 mm), the external lateral lobe is distinctly trifid.At Dm over 30 m, lateral digits of the lobe L are con�siderably reduced. The new species differs from N. tri�ceps Ruzhencev and N. hyperboreus Ruzhencev in thedistinctly trifid shape of the inner lobes at the middlestage of shell ontogeny (see Figs. 2a–2e) and subtrian�gular cross�section of the inner whorls.

M a t e r i a l. Two specimens from the type locality(holotype and paratype PIN, no. 1802/253).

Neoshumardites? nassichuki Kutygin et Ganelin, sp. nov.

Plate 1, figs. 3–7

E t y m o l o g y. In honor of W. Nassichuk, Cana�dian geologist and paleontologist.

H o l o t y p e. PIN, no.1802/252; Omolon Massif,Munugudzhak River; upper part of the MunugudzhakFormation, Sakmarian–Artinskian boundary beds,provisionally Upper Sakmarian Substage.

S h e l l s h a p e.. The holotype is represented by afragment of the external whorl and strongly recrystal�lized distorted incompletely preserved medium�sizedphragmocone. No precise measurements were possi�ble. The shell is large, wide, moderately evolute. Theumbilical walls are relatively narrow, slightly flattened,and steep. The venter is very wide and rounded. Atmedium shell size the umbilical wall is wide, flattened,and very steep (almost vertical). Ornamentation. Thefragment of the external whorl has a constrictionforming a shallow, but very broad ventral sinus. Theshell surface ornamentation is incompletely preserved.At Dm = 30 mm it possesses numerous small ran�domly arranged tubercles (papillate ornamentation)(Pl. 1, figs. 5–7). There are not more than 20 papillaeper 1 mm2 of the shell surface. The papillae are about0.1 mm wide, rounded, and dorsoventrally flattened.

S u t u r e. (Figs. 2f–2h). The ventral lobe is com�posed of two very narrow deep prongs and a highmedian saddle. The prongs are lanceolate, asymmetri�cal, with a more convex inner side. The first lateralsaddle is high, slightly compressed in the middle, and

(a)

(b)

(c)

(d)

(e)

Fig. 1. (a–c) Sutures, (d) constriction, and (e) cross sec�tion of Neoshumardites munugudzhensis sp. nov. (holotypePIN, no. 1802/41): (a) at Dm = 15 mm, WW = 11.4 mm,WH = 6.4 mm; (b) at Dm = 24 mm, WW = 18 mm,WH = 10 mm; (c) at Dm about 67 mm, WW = 38.5 mm,WH = 22 mm; (d) at Dm about 63 mm, WW = 37 mm,WH = 21.5 mm; (e) at Dm = 70 mm. The scale bars are1 mm.

E x p l a n a t i o n o f P l a t e 1

Figs. 1 and 2. Neoshumardites munugudzhensis Kutygin et Ganelin sp. nov., holotype PIN, no. 1802/41: (1a) ventral view,(1b) lateral view, (1c) apertural view, all ×1; (2a) lateral view, (2b) apertural view, (2c) ventrolateral view; all ×1.5.Figs. 3–7. Neoshumardites? nassichuki Kutygin et Ganelin sp. nov., holotype PIN, no. 1802/252: (3) lateral view, ×1.5; (4a) ven�tral view, (4b) lateral view, both ×1; (5–7) papillate ornamentation: (5) ×10, (6) ×40, (7) ×155.Omolon Massif, Munugudzhak River; upper part of the Munugudzhakian Formation, Sakmarian–Artinskian boundary beds,provisionally Upper Sakmarian Substage; collected by V.G. Ganelin, Sample 11–3/VG–77. The arrow points at the borderbetween the phragmocone and the body chamber.



Plate 1

200 µm

1b

2а 2b 2c3

5

4а 4b

6 7100 µm

1c

1a

6


KUTYGIN, GANELIN

pointed at the top. The deep, narrow lateral lobe isV�shaped, with small rounded shoulders in the mid�flanks on both sides. The umbilical lobe is not deepand is funnel�shaped and is located between two asym�metrical saddles. The inner lateral lobe is narrow, shal�low, lanceolate, with a more convex inner side. Thedorsal saddle is asymmetrical, follows the shape of thefirst external lateral saddle (Fig. 2f). The dorsal lobe ismoderately deep, narrow, and spindle�shaped. At ear�lier stages of shell ontogeny, the lateral lobe is distinctlytrifid (Figs. 2g–2h), which is characteristic of adult N.triceps, N. hyperboreus, and N. munugudzhensis(Figs. 2b–2e).

C o m p a r i s o n. This species is distinguishedfrom all known species of the genus Neoshumardites by

the ventral lobe with unusually long and narrowprongs.

R e m a r k s. The suture of this species is distin�guished from that of other species of the genus by itsmore primitive shape with very narrow asymmetricalventral prongs with more strongly flattened flanks.This is somewhat similar to the sutural outline of theSakmarian genus Andrianovia, for which a similarsutural outline was figured by Ruzhencev (1951, text�fig. 41a). It also shows strong similarity to the suture of“N. cf. sakmarae (Ruzhencev)” from the Lower Per�mian of the southwest Ellesmere Island of Arctic Can�ada (Nassichuk, Furnish, and Glenister, 1965, text�fig. 2C). Judging from the description, Ellesmerespecimens possess distinct longitudinal ornamenta�tion (at Dm = 80 cm 12 spirals are observed per 1 cmof shell surface); hence “N. cf. sakmarae(Ruzhencev)” should be assigned to the Andri�anovian. These Ellesmere “Neoshumardites” Saunders(1971) assigned to Somoholites deroeveri Saunders[=Andrianovia deroeveri according to Borisenkov(2004)], the type collection of which comes from theSakmarian of the Permian portion of the KeknenoSeries on Timor. We are not certain that it was correctto assign the Ellesmere and Timorian Andrianov to thesame species; hence we treat the Ellesmere specimensdescribed by Nassichuk, Furnish, and Glenister asAdrianovia cf. sakmarae (Ruzhencev). Interestinglythe suture of the new species is extremely similar tothat of the Carboniferous genus Syngastrioceras(Saunders, 1971, text�fig. 2D), which is consideredancestral to the family Somoholitidae (Ruzhencev andBogoslovskaya, 1978). Similar to our specimen, Syn�gastrioceras globosum described by Saunders shows amirror repetition of configuration of the oppositeexternal and internal asymmetrical saddles: the firstexternal lateral saddle with the first dorsal saddle, andthe second external lateral saddle with the second dor�sal saddle. Nassichuk (1971, pl. 124, figs. 4, 5)recorded a very wide specimen of Eoasianites aff. trap�ezoidalis Maximova from the Lower Sakmarian of theJungle Creek Formation of the Peel River with a suturevery similar to that of N.? nassichuki. Unfortunatelywe are not able to explain the similarity of the suturaloutlines of these unrelated taxa, but the fact itself israther remarkable.

M a t e r i a l. Holotype.

S u p e r f a m i l y Schistoceratoidea Schmidt, 1929

?Family Orulganitidae Ruzhencev, 1965

Genus Bulunites Andrianov, 1985

Bulunites gracilis Kutygin et Ganelin, sp. nov.

Plate 2, figs. 1–3

E t y m o l o g y. From the Latin gracilis (gracile).H o l o t y p e. PIN, no. 1802/224; Omolon Massif,

Munugudzhak River; upper part of the Munu�

(a) (b)

(c) (d)

(e)

(f)

(g) (h)

Fig. 2. Sutures of Neoshumardites: (a, b) N. tricepsRuzhencev, specimen PIN, no. 317/4419: (a) at WW =27 mm, WH = 16.2 mm (Ruzhencev, 1956, text�fig. 43d);(b) at WW = 30 mm (Ruzhencev, 1956, text�fig. 43e);South Urals, left bank of the Aktasty River, ArtinskianStage, Aktastynian; (c, d) N. hyperboreus Ruzhencev,holotype PIN, no. 1802/5: (c) at WW = 27.5 mm, WH =14 mm (Ruzhencev, 1961, text�fig. 5a); (d) at WW =43 mm (Ruzhencev, 1961, text�fig. 5b); western Verkhoy�ansk Region, lower reaches of the Delendzha River,Echian, Artinskian Stage; (e) N. munugudzhensis sp. nov.,holotype PIN, no. 1802/41 at Dm = 38 mm, WW =27 mm, WH = 15.5 mm; Munugudzhak River, upper partof the Munugudzhakian Formation, Sakmarian–Artin�skian boundary beds, provisionally Upper Sakmarian Sub�stage; (f–h) N.? nassichuki sp. nov., holotype PIN, no.1802/252: (f) at WW = 39 mm, WH = 25 mm, suturereversed; (g) lateral lobe at WH about 14 mm, reversed;(h) the same at WH about 8 mm; the same age and locality.The scale bars are 1 mm.



(b)

(a)

Fig. 3. Transverse ornamentation of Bulunites mezhvilkiAndrianov (a) and B. gracilis sp. nov.: (a) specimen PIN,no. 55/243, reversed, ×2.5; western Verkhoyansk Region,Dugalakh River, Echii River basin, lower part of theEchian Formation, Upper Asselian–Lower Sakmarianbeds; (b) specimen PIN, no. 1802/221, ×1.5; Munu�gudzhak River, upper part of the Munugudzhakian Forma�tion, Sakmarian–Artinskian boundary beds, provisionallyUpper Sakmarian Substage. The scales bars are 1 mm. Thearrows indicate the direction toward the aperture.

gudzhakian Formation, Sakmarian–Artinskian bound�ary beds, provisionally Upper Sakmarian Substage.

S h e l l s h a p e.. At medium and large sizes theshell is narrow with an umbilicus ranging from moder�ately narrow to medium�size (subvirgacone and sub�discocone). The external portion of the whorl is repre�sented by the narrow flattened venter, wide flattenedflanks and narrow sloping umbilical wall. The whorlcross�section is high subtrapezoid with a maximumwidth in the umbilical zone.

D i m e n s i o n s i n m m a n d r a t i o s i n %:

O r n a m e n t a t i o n. At Dm = 50 mm, the shell iscovered by fine sickle�shaped riblets (Fig. 3b), which

Specimen PIN, no. Dm WW WH UW WW/

DmWH/Dm

UW/Dm

WW/WH

Holotype 1802/224

46.0 16.0 18.5 14.0 34.8 40.2 30.4 86.5

35.0 13.0 14.5 10.5 37.1 41.4 30.0 89.7

25.0 10.5 11.0 7.0 42.0 44.0 28.0 95.5

begin near the umbilical seam, are slightly inclinedforward on the umbilical wall, near the umbilicalshoulder bending in a narrow, low projection, cross theflank forming a very broad lateral sinus, and arestraightened on the venter to form a shallow sinus.There are about 40–45 riblets per half�whorl. Theshell surface ornamentation is incompletely preservedas a fine reticulate pattern, only on the surface of spec�imen PIN, no. 1802/239. The umbilical zone of theflanks possesses more strongly pronounced transversestriae, while the spirals are almost indiscernible, whichis also characteristic of the type species of Bulunites.

S u t u r e. (Fig. 4c). The ventral lobe (V1V1) is com�posed of two wide lanceolate prongs with flattenedinner side and convex outer side. The moderately highmedian saddle narrows toward its top. The first exter�nal saddle V/L is very high and broad, and is almost

Fig. 4. Sutures and transverse ornamentation of Bulunitesmezhvilki Andrianov (a, b) and B. gracilis sp. nov. (c, d):(a, b) holotype PIN, no. 55/182: (a) external portion of thesuture at Dm = 9 mm, WW = 5 mm, WH = 4 mm, (b) con�striction at Dm = 13 mm, WW = 7 mm, WH = 6 mm;Kharaulakh, right bank of the Lena River, upstream of theKubalakh River mouth, lower part of the Tuora�Sis For�mation, Upper Asselian–Lower Sakmarian Beds;(c) external portion of the suture of holotype PIN,no. 1802/224 at Dm = 35 mm, WW = 13 mm, WH =14.5 mm; Munugudzhak River, upper part of the Munu�gudzhak Formation, Sakmarian–Artinskian boundary beds,provisionally Upper Sakmarian Substage; (d) reconstructionof the riblets in specimen PIN, no. 1802/219 at Dm about45 mm; the same locality. All scale bars are 1 mm.

(a)

(b)

(c)

(d)

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KUTYGIN, GANELIN

Plate 2

1а 1b 2

3а

3b

4а 4b 5

7

8а 8b

9

10

11а 11b 12

1314

15а 15b 15c 16а 16b 16c

6



symmetrical. The helmet�shaped lobe L is consider�ably broader than the ventral prongs, but is shallower.The low and broad second external saddle L/U widenstoward the base from its narrow, rounded top. Thebroad, weakly pointed base of the shallow, wide, fun�nel�shaped umbilical lobe U lies on the umbilical wall,slightly towards the umbilical shoulder.

C o m p a r i s o n. This species differs fromB. mezhvilki Andrianov from the Khorotykian Hori�zon of the Verkhoyansk Region (Andrianov, 1985;Kutygin, 2006) in the narrower shell (WW/Dm = 34–35,instead of 45) and in densely spaces riblets (as opposedto widely spaced). These two species are similar inhaving biconvex transverse ornamentation and dis�tinctly helmet�shaped lateral lobe (Fig. 4).

M a t e r i a l. Six specimens of various states ofpreservation from the type locality (holotype andparatypes PIN, nos. 1802/213, 219, 221, 239, 250).

ACKNOWLEDGMENTS

Specimen photographs were taken by R.V. Kutyginand A.G. Stepanov in the Institute of Diamond andPrecious Metals Geology, Siberian Branch, RussianAcademy of Sciences. We are grateful to T.B. Leonova(PIN) for critically reviewing the paper and for valu�able suggestions.

The study was supported by the Russian Founda�tion for Basic Research (project nos. 09�04�00757,11�05�00053, 11�05�00950, 11�05�98569�r_east)and Program no. 23 of the Russian Academy of Sci�ences.

REFERENCES

Andrianov, V.N., Permskie i nekotorye kamennougol’nyeammonoidei Severo�Vostoka Azii (Permian and Some Car�boniferous Ammonoids of Northeastern Asia), Novosi�birsk: Nauka, 1985.

Boardman, D.R. II, Work, D.M., Mapes, R.H., and Bar�rick, J.E., Biostratigraphy of Middle and Late Pennsylva�nian (Desmoinesian–Virgilian) Ammonoids, Kansas Geol.Surv. Bull., 1994, no. 232, pp. 1–121.

Bogoslovskaya, M.F. and Boiko, M.S., The Evolution andDistribution of the Early Permian Genus Uraloceras(Ammonoidea), Paleontol. J., 2002, vol. 36, no. 6, pp. 598–605.

Boiko, M.S., Evolution of the Early Permian Family Para�gastrioceratidae (Ammonoidea) in the Urals, Paleontol. J.,2010, vol. 44, no. 3, pp. 275–281.

Borissenkov, K.V., On Some Permian Somoholitids(Ammonoidea) from the Ural Mountains, Paleontol. J.,2004, vol. 38, no. 1, pp. 20–26.

Ganelin, V.G., Taimyr–Kolyma Subregion, in Osnovnyecherty stratigrafii permskoi sistem SSSR: Tr. VSEGEI, T. 286(Main Stratigraphic Features of the Permian System of theUSSR: Proc. Vses. Geol. Inst., Vol. 286), Leningrad: Nedra,1984, pp. 111–123.

Kutygin, R.V., Shell Shapes of Permian Ammonoids fromNortheastern Russia, Paleontol. J., 1998, vol. 32, no. 1,pp. 20–31.

Kutygin, R.V., Budnikov, I.V., Byakov, A.S., and Klets, A.G.,Beds with Permian Ammonoidea in the Upper YanaRegion, Otechestv. Geol., 2002, no. 4, pp. 66–71.

Kutygin, R.V., Areal Distribution of Permian AmmonoidAssociations in the Verkhoyansk Region, Otech. Geol., 2004,no. 5, pp. 75–81.

Kutygin, R.V., Permian Ammonoid Associations of theVerkhoyansk Region, Northeast Russia, J. Asian Earth Sci.,2006, vol. 26, nos. 3–4, pp. 243–257.

Kutygin, R.V., Budnikov, I.V., Biakov, A.S., Goryaev, S.K.,Makoshin, V.I., and Peregoedov, L.G., New Data on theStratigraphic Relationship between Brachiopods of theGenus Jakutoproductus and Inoceramus�Like Bivalves fromthe Lower Permian of the Western Verkhoyansk Region,Otech. Geol., 2010, no. 5, pp. 97–104.

Kutygin, R.V. and Ganelin, V.G., Permian Ammonoids ofthe Kolyma–Omolon Region: Kyrian Association, Paleon�tol. J., 2011, vol. 45, no. 3, pp. 249–259.

Leonova, T.B., Permian Ammonoids: Classification andPhylogeny, Paleontol. J., 2002, vol. 36, suppl. 1, pp. S1–S114.

Mikesh, D.L., Glenister, B.F., and Furnish, W.M.,Stenolobulites n. gen., Early Permian Ancestor of Predomi�nantly Late Permian Paragastrioceratid Subfamily Pseudo�gastrioceratinae, Univ. Kans. Paleontol. Contrib., Pap. 123,Lawrence: Paleontol. Inst., Univ. Kansas, 1988.

E x p l a n a t i o n o f P l a t e 2

Figs. 1–3. Bulunites gracilis Kutygin et Ganelin sp. nov., ×1: (1) holotype PIN, no. 1802/224, (1a) ventral view, (1b) lateral view;(2) specimen PIN, no. 1802/221, lateral view; (3) specimen PIN, no. 1802/219, lateral view.Figs. 4–16. Uraloceras omolonense Bogoslovskaya et Boiko, 2002: (4) specimen PIN, no. 1802/222, ×1: (4a) ventral view,(4b) lateral view; (5) specimen PIN, no. 1802/215, lateral view, ×1; (6) specimen PIN, no. 1802/238, lateral view, ×1; (7) speci�men PIN, no. 1802/226, lateral view, ×1; (8) specimen PIN, no. 1802/240, ×1.5: (8a) lateral view, (8b) ventral view; (9) specimenPIN, no. 1802/229, lateral view, ×1.5; (10) specimen PIN, no. 1802/209, lateral view, ×1; (11) specimen PIN, no. 1802/225, ×1:(11a) ventral view, (11b) lateral view; (12) specimen PIN, no. 1802/227, lateral view, ×1.5; (13) specimen PIN, no. 1802/232,lateral view, ×2; (14) specimen PIN, no. 1802/214, lateral view, ×1; (15) specimen PIN, no. 1802/231; ×2: (15a, 15c) lateral view,(15b) ventral view; (16) specimen PIN, no. 1802/242, ×4: (16a) apertural view, (16b) lateral view, (16c) ventral view.Omolon Massif, Munugudzhak River, upper part of the Munugudzhakian Formation, Sakmarian–Artinskian boundary beds,provisionally Upper Sakmarian; collected by V.G. Ganelin, Sample 11–3/VG–77. The arrow points at the border between thephragmocone and the body chamber.

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Nassichuk, W.W., Furnish, W.M., and Glenister, B.F., ThePermian Ammonoids of Arctic Canada, Bull. Geol. Surv.Can., 1965, no. 131, pp. 1–56.

Nassichuk, W.W., Permian Ammonoids and Nautiloids,Southeastern Eagle Plain, Yukon Territory, J. Paleontol.,1971, vol. 45, no. 4, pp. 1001–1021.

Ruzhentsev, V.E., Nizhnepermskie ammonity YuzhnogoUrala. I. Ammonity sakmarskogo yarusa: Tr. Paleontol. Inst.Akad. Nauk SSSR. T. 33 (Lower Permian Ammonites of theSouthern Urals: 1. Ammonites of the Sakmarian Stage:Proc. Paleontol. Inst. Acad. Sci. USSR, Vol. 33), Moscow�Leningrad: Akad. Nauk SSSR, 1951.

Ruzhentsev, V.E., Nizhnepermskie ammonity YuzhnogoUrala. II. Ammonity artinskogo yarusa: Tr. Paleontol. Inst.Akad. Nauk SSSR. T. 60 (Lower Permian Ammonites of theSouthern Urals: 2. Ammonites of the Artinskian Stage:Proc. Paleontol. Inst. Acad. Sci. USSR, Vol. 60), Moscow:Akad. Nauk SSSR, 1956.

Ruzhentsev, V.E., Ammonoids and Chronostratigraphy ofthe Carboniferous of Eastern Siberia, Paleontol. Zh., 1975,no. 2, pp. 28–45.Ruzhentsev, V.E., Biochronotype or Stratotype?, Paleontol.Zh., 1977, no. 2, pp. 23–34.Ruzhentsev, V.E. and Bogoslovskaya, M.F., Namyurskii etapv evolyutsii ammonoidei. Pozdnenamyurskie ammonoidei:Tr. Paleontol. Inst. Akad. Nauk SSSR. T. 167 (NamurianStage in the Evolution of Ammonoidea: Late NamurianAmmonoidea: Proc. Paleontol. Inst. Acad. Sci. USSR,Vol. 167), Moscow: Nauka, 1978.Saunders, W.B., The Somoholitidae: Mississippian to Per�mian Ammonoids, J. Paleontol., 1971, vol. 45, no. 1,pp. 100–118.Schiappa, T.A., Hemmesch, N.T., Spinosa, C., and Nassi�chuk, W.W., Cisuralian Ammonoid Genus Uraloceras inNorth America, J. Paleontol., 2005, vol. 79, no. 2, pp. 366–377.

Permian Ammonoids of the Kolyma–Omolon Region: Ogonerian Association 2013

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