mesozoic salamanders and albanerpetontids of middle asia, kazakhstan, and siberia

REVIEW

Mesozoic salamanders and albanerpetontids of Middle Asia,Kazakhstan, and Siberia

Pavel P. Skutschas

Received: 25 March 2013 /Revised: 29 May 2013 /Accepted: 10 July 2013 /Published online: 1 October 2013# Senckenberg Gesellschaft für Naturforschung and Springer-Verlag Berlin Heidelberg 2013

Abstract Mesozoic terrestrial deposits containing diverse ver-tebrate assemblages are widely distributed in Siberia (centraland eastern part of Russia), Middle Asia (Kyrgyzstan, Tajiki-stan, Turkmenistan and Uzbekistan), and Kazakhstan. Twelveformations of Middle Jurassic (Bathonian) to Late Cretaceous(Campanian) age in the region contain salamanders (six inMiddle Asia, two in Siberia and four in Kazakhstan). In con-trast to the situation in Euramerica, albanerpetontids are ex-tremely rare in the Mesozoic of Asia, where their fossil recordis limited to the Khodzhakul (Cenomanian) and Bissekty(Turonian) formations, both in Uzbekistan. Salamanders inSiberia are known from the Bathonian Itat Formation in theKrasnoyarsk Region (the stem salamander Urupia monstrosaand two undescribed taxa—a new stem salamander and apossible crown-group salamander) and from theAptian–AlbianIlek Formation in Kemerovo Province and the KrasnoyarskRegion (the crown-group salamander Kiyatriton leshchinskiyiand Caudata indet.). In the Jurassic of Middle Asia, the stemsalamanders Kokartus honorarius and Karauridae indet. areknown from the Bathonian–Callovian Balabansai Formationin Kyrgyzstan. Younger records inMiddle Asia are restricted toonly two Late Cretaceous genera of crown-group salamanders:the possible cryptobranchoid Nesovtriton in the Bissekty For-mation (Turonian) and the cryptobranchid Eoscapherpeton inthe Khodzhakul, Dzharakuduk, Bissekty, and Aitym forma-tions (collectively Cenomanian–Campanian) in Uzbekistanand the Yalovach Formation (Santonian) in Tajikistan. In Ka-zakhstan, salamanders are known from the KimmeridgianKarabastau Formation (the stem salamander Karaurussharovi), the Turonian Zhirkindek Formation (Caudata indet.),

the Santonian–Campanian Bostobe Formation (thecryptobranchid Eoscapherpeton, the possible proteid “Bisharabacka” and Caudata indet.) and the Campanian Darbasa For-mation (the cryptobranchid Eoscapherpeton). Cenomanian–Campanian vertebrate assemblages in Middle Asia and Ka-zakhstan are characterised by dominance of the cryptobranchidEoscapherpeton.

Keywords Mesozoic . Caudata . Albanerpetontidae .MiddleAsia . Kazakhstan . Siberia

Introduction

Salamanders (Caudata) and albanerpetontids (Albanerpetontidae)are clades of Mesozoic and Cenozoic lissamphibians with pre-dominantly Laurasian distributions and superficially similar ex-ternal morphologies (i.e. well-developed tail and primitive fore-and hindlimbs limbs of nearly equal size) (e.g. Gardner 2001;Gardner and Böhme 2008; Milner 2000). Skeletal morphologiesof these groups differ in many features. Salamanders arecharacterised by: (1) pedicellate and bicuspid teeth (non–pedicel-late and monocuspid in some neotenic salamanders); (2) a short-ened anterior ramus of the pterygoid that is free of bony contactsanteriorly (elongated anterior ramus of the pterygoid in someneotenic salamanders); (3) absence of palatine (present in someneotenic salamanders); (4) parietal-squamosal contact (absent insome advanced salamanders); (5) absence of denticles onparasphenoid (also present in some lepospondyls); (6) onescapulocoracoid ossification (also present in many lepospondylsand non-lissamphibian temnospondyls, versus separate scapulaand coracoid ossification in modern sirenid salamanders); (7)bicipital rib-bearers (closely appressed or unicipital in somesalamanders) (e.g. Gardner 2001; Milner 2000; Skutschas andMartin 2011). Albanerpetontids are easily defined by such fea-tures as (1) fused frontals; (2) non–pedicellate, tricusped andchisel–like teeth; (3) an interdigitating intermandibular joint; (4)

This article is a contribution to the special issue “Mesozoic and Cenozoiclissamphibian and squamate assemblages of Laurasia”

P. P. Skutschas (*)Vertebrate Zoology Department, Biology Faculty Saint PetersburgState University, Universitetskaya nab. 7/9, Saint Petersburg 199034,Russian Federatione-mail: [email protected]

Palaeobio Palaeoenv (2013) 93:441–457DOI 10.1007/s12549-013-0126-8

specialised “cervical” vertebrae that are convergently similar tothe atlas–axis complex of mammals (note that palatal anatomy isnot known for albanerpetontids) (see Gardner 2001; Gardner andBöhme 2008 and references therein). Salamanders andalbanerpetontids both appear in the fossil record during theMiddle Jurassic and survived across the K-T boundary, but havedifferent Cenozoic evolutionary histories—albanerpetontidswentextinct in the Pliocene, while salamanders have persisted to thepresent day (Delfino and Sala 2007; Gardner and Böhme 2008;Milner 2000).

According to recent phylogenetic analyses, the most likelysister-group for salamanders are frogs (Marjanović and Laurin2008; Ruta and Coates 2007; Sigurdsen and Green 2011;Skutschas and Martin 2011) or albanerpetontids (Andersonet al. 2008). The phylogenetic position of albanerpetontids is lesscertain; they have been proposed as the sister-group of Caudata(Anderson et al. 2008), of Batrachia (frogs + salamanders; Gard-ner 2001; Skutschas and Martin 2011), of Gymnophiona (Rutaand Coates 2007) or of other lissamphibians (salamanders +frogs + caecilians; Marjanović and Laurin 2008).

In addition to their osteological differences, salamandersand albanerpetontids differ in their taxonomic diversities anddistributions in Mesozoic lissamphibian assemblages. Sala-manders in the Mesozoic are represented by more than 25genera, containing more than 30 species, whereas the entireMeso-Cenozoic albanerpetontid diversity is restricted to fournamed genera and about a dozen species (Gardner and Böhme2008; Milner 2000; Sweetman and Gardner 2013). Alba-nerpetontids were extremely rare in Late Mesozoic lissam-phibian assemblages in Asia, where they are known only fromthe Late Cretaceous of Middle Asia (see below), yet they wererelatively common in both Europe (Middle Jurassic–Late Cre-taceous) andNorthAmerica (only in the Cretaceous) (Skutschas2007; Szentesi et al. 2013). By contrast, salamanders wereabundant inMesozoic lissamphibian assemblages in Asia (sincethe Middle Jurassic), in North America (since the Late Jurassic)and in Europe (Middle Jurassic–Early Cretaceous, but not in theLate Cretaceous) (e.g. Szentesi et al. 2013).

Middle Asia (a region which encompasses Kyrgyzstan,Tajikistan, Turkmenistan and Uzbekistan), Kazakhstan andSiberia together comprise a huge Asiatic territory that containswidely distributedMesozoic terrestrial deposits (Nesov 1997).Twelve geological formations in this territory contain sala-mander remains (six inMiddle Asia, two in Siberia and four inKazhakhstan), but only two of these (both in Middle Asia)contain albanerpetontid remains (Fig. 1). Mesozoic salaman-ders and albanerpetontids from these regions are of particularinterest for following reasons: (1) Jurassic salamanders fromMiddle Asia, Siberia and Kazakhstan are among the firstsalamanders in the fossil record; (2) the only records of LateCretaceous salamanders in Asia are from Middle Asia andKazakhstan; (3) the only records of albanerpetontids in Asiaare from Middle Asia; (4) in Middle Asia and Kazakhstan, a

well-documented sequence of the Upper Cretaceous terrestrialdeposits (from Cenomanian to Campanian) containing sala-mander remains provides the opportunity to trace the regionalevolutional history of salamanders during an approximately20-million-year interval.

In this review, I provide updated information on the records ofMesozoic salamanders and albanerpetontids from Middle Asia,Kazakhstan and Siberia (focusingmostly on the taxa whichwereinadequately described previously, but also on new findings),discuss some aspects of taxonomy and palaeobiogeography ofMesozoic salamanders and albanerpetontids and briefly discussthe potential for the future studies.

The abbreviations for the institutes mentioned herein are:CCMGE, Chernyshev’s Central Museum of Geological Explo-ration, Saint Petersburg, Russia; ZIN PH, Paleoherpetologicalcollection, Zoological Institute, Russian Academy of Sciences,Saint Petersburg, Russia.

Transliterating names of people, localities, and stratigraphicrock units from Russian into English is challenging due todifferences between the Russian and English alphabets in termsof both characters and how sounds are pronounced and theexistence of several methods for transliterating Russian intoEnglish (for discussion and examples, see Benton 2000). As aresult, there can be two or more English language variants of aRussian name. For example, the original Russian surname"Несов" can be transliterated as “Nessov” or “Nesov”. Here Iuse the latter spelling, which is a direct and precise transliter-ation using rules recommended by M. Benton (2000). Theother variant (“Nessov”) is a looser transliteration that attemptsto more closely approximate English pronunciation and, forthat reason, may be more familiar to most English readers.

Siberian record

Jurassic salamanders

Remains of one of the oldest salamanders were found in theBerezovsk Quarry locality in the Bathonian Itat Formation ofWestern Siberia (Averianov et al. 2005; Skutschas 2006;Skutschas and Krasnolutskii 2011; Fig. 2). One salamandertaxon, Urupia monstrosa, was recently described based on iso-lated fragmentary cranial and postcranial bones from theBerezovsk Quarry (Skutschas and Krasnolutskii 2011; Fig. 3a–c, g–i, l). The combination of its large size, the absence of spinalnerve foramina in the atlas and its sculptured vertebral surfacetexture (Fig. 3a–c, g–i) suggests thatUrupiamonstrosa is a stem-group salamander. The phylogenetic relationships of Urupiamonstrosa with other stem-group salamanders cannot beestablished on the available material (Skutschas andKrasnolutskii 2011). Nevertheless, it is worth noting that theatlas of Urupia is similar to that of another stem salamander,

442 Palaeobio Palaeoenv (2013) 93:441–457

namelyMarmorerpeton from the Bathonian Forest Marble For-mation in the UK (Evans et al. 1988).

Salamanders in the Beresovsk Quarry are represented byseveral taxa. In addition to material assigned to Urupia, fourdistinctive morphotypes (one atlantal, one trunk vertebral andtwo dentary; Fig. 3d–f, j, k, m, n) can be recognised. Theatlantal morphotype is represented by atlantes belonging to astem salamander (Fig. 3d–f) which differs from that ofUrupia(Fig. 3a–c) in lacking both atlantal transverse processes and adeep depression on the ventral surface and in having morerounded anterior cotyles (vs. oval and dorsoventrally com-pressed in Urupia). Pending its formal description, here Iinformally call this new taxon “Berezovsk salamander A”.Examples of the trunk vertebral morphotype (Fig. 3j–k) differfrom those of Urupia (Fig. 3g–i) in being relatively shorter(ratio of midline length:maximum height of centra is about1.2–1.3 vs. about 1.4 in Urupia) and in having more widelyseparated dia- and parapophyses. These trunk vertebrae arepreliminarily referred to as “Berezovsk salamander A” be-cause they are in the same size category and have relatively

short vertebral centra. Both new morphotypes of dentaries(Fig. 3m–n) strongly differ from Urupia (Fig. 3l) in lackingboth a sharp ridge along the ventral edge of the presymphysealregion and sculpture on the lateral surface, in being smaller inabsolute size and in the position and structure of theMeckelian groove. One of these morphotypes (Fig. 3m) iscomparable in size with “Berezovsk salamander A” and, onthat basis, might also be referable to that taxon. The otherdentary morphotype is represented by a very small, lightlybuilt dentary (Fig. 3n) belonging to a different, crown-group salamander (here called “Berezovsk salamander B”,pending its formal description). To summarise, specimenscurrently available establish the presence of at least threesalamander taxa in the vertebrate assemblage of theBerezovsk Quarry.

Cretaceous salamanders

Early Cretaceous salamanders are known from three localities(Shestakovo, Bol’shoi Kemchug 3 and Bol’shoi Terekhtul’ 2)

Fig. 1 Stratigraphic correlation chart for Mesozoic formations in MiddleAsia, Kazakhstan and Siberia containing salamander and albanerpetontidremains. Correlations are based on Averianov and Sues (2012). Letters to

the right of the formation names indicate the presence of salamanders (S)and albanerpetontids (A)

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in the Aptian–Albian Ilek Formation, Western Siberia(Averianov and Voronkevich 2002; Skutschas 2006; Fig. 2).One crown-group salamander, Kiyatriton leshchinskiyi, wasdescribed from the Shestakovo locality on the basis of anatlantal centrum and femoral fragments (Averianov andVoronkevich 2002). According to these specimens and newlycollected material, Kiyatriton leshchinskiyi is characterised byan atlas with a spinal nerve foramen and an intercotylartubercle with a low, but dorsally distinct median ridge, bydentaries bearing closely spaced, pedicellate teeth, and byfemora with ossified epiphyses (Averianov and Voronkevich2002; Skutschas 2006). The atlantal structure of Kiyatritonleshchinskiyi is similar to that of cryptobranchoids in thefollowing features: (1) intercotylar tubercle is gutter-likeand without a constricted base; (2) articular surface ofanterior cotyles is flat and (3) anterior cotylar surfacesare continuous across lateral and ventral surfaces of theintercotylar tubercle (Fig. 4a–d). The trunk vertebra andfemur of Kiyatriton leshchinskiyi are generally similar tothose of extant hynobiids; for example, trunk vertebraebear unicipital rib-bearers, a flattened neural arch, neuralspine reduced to a low keel and a reduced sub-central keel,and femora have a reduced crista trochanterica (Skutschas2006). The phylogenetic position of Kiyatriton within

Urodela is still uncertain, but the above-mentioned suiteof features indicates possible cryptobranchoid affinities.Remains of salamanders in two other localities of the IlekFormation are rare, with just two other specimens havingbeen found: the proximal part of a femur, similar to that ofKiyatriton (Skutschas 2006), at Bol’shoi Kemchug 3, anda fragmentary maxilla (Fig. 4e–f) at Bol’shoi Terekhtul’ 2.The latter specimen is characterised by a relatively highdorsal process having a nearly vertical anterior edge and anincisure in its dorsal edge (Fig. 4e–f). This maxilla is in

�Fig. 3 Salamander remains from Berezovsk Quarry, Krasnoyarsk Re-gion, Western Siberia, Russia (Itat Formation, Middle Jurassic,Bathonian). a–c ZIN PH 1/144, holotype, incomplete atlas of Urupiamonstrosa in anterior (a), right lateral (b) and ventral (c) views. d–f ZINPH 5/144, incomplete atlas of “Berezovsk salamander A” in anterior (d),right lateral (e) and ventral (f) views. g–i ZIN PH 3/144 fragment of trunkvertebra ofUrupia monstrosa in right lateral (g), ventral (h) and posterior(i) views. j, k ZIN PH 6/144, fragment of trunk vertebra of “Berezovsksalamander A” in right lateral (j) and posterior (k) views. l ZIN PH2/144,anterior fragment of left dentary of Urupia monstrosa in medial view. mZIN PH 7/144, anterior fragment of right dentary of ? “Berezovsksalamander A” in medial view. n ZIN PH 8/144, fragment from behindsymphyseal region of left dentary of “Berezovsk salamander B” in medialview. diap Diapophysis, Mcg Meckelian groove, parap parapophysis.Specimens are shown at different magnifications

Fig. 2 Map showingMesozoic salamander and albanerpetontid localitiesmentioned in text in Middle Asia, Kazakhstan and Siberia. Inset Map ofcentral and northern portions of Asian continent depicting territory ofMiddle Asia in light grey, Kazakhstan inmedium grey, and Siberia in darkgrey. 1 Khodzhakul and Sheikhdzheili (Khodzhakul Formation,Cenomanian), both Middle Asia, Uzbekistan. 2 Itemir (DzharakudukFormation, Cenomanian), Dzharakuduk (Bissekty Formation, Turonian)and Aitym (Aitym Formation, Coniacian–Santonian), all Middle Asia,Uzbekistan. 3 Tulkeli (Zhirkindek Formation, Turonian), Kazakhstan. 4Shakh-Shakh and Baybishe (Bostobe Formation, Santonian–early

Campanian), both Kazakhstan. 5 “Grey Mesa” (= Alymtau 1) (DarbasaFormation, Campanian), Kazakhstan. 6Mikhailovka (Karabastau Forma-tion, Kimmeridgian), Kazakhstan. 7 Kansai (Yalovach Formation,Santonian), Middle Asia, Tajikistan. 8 Kyzylsu 1, Kugart 1 and Nichke1 (lower part of Balabansai Formation, Bathonian), all Middle Asia,Kyrgyzstan. 9 Dzhiddasai (site FBX-23) (upper part of Balabansai For-mation, Callovian), Middle Asia, Kyrgyzstan. 10 Shestakovo (Ilek For-mation, Aptian–Albian), Siberia, Russia. 11 Berezovsk Quarry (Itat For-mation, Bathonian), Siberia, Russia. 12Bol’shoi Kemchug 3 and Bol’shoiTerekhtul’ 2 (Ilek Formation, Aptian–Albian), both Siberia, Russia


the same size category as other Kiyatriton material, butassignment of this specimen to Kiyatriton leshchinskiyi isimpossible at this time due to a lack of information aboutmaxillary structure in this taxon.

Middle Asian record

Triassic salamanders

The problematic taxon Triassurus sixtelae from the UpperTriassic Madygen Formation in southern Kyrgyzstan wasdescribed by Ivakhnenko (1978) on the basis of the impres-sion of a poorly preserved and weakly ossified skeleton.Ivakhnenko (1978) interpreted this taxon as a caudate butdid not provide support for this assignment. Estes (1981)noted that the only feature common to Triassurus sixtelaeand salamanders—cheek region open laterally—is not suffi-cient for identifying this Triassic taxon as a salamander, be-cause it is also characteristic for branchiosaurids (non-lissamphibian temnospondyls). Estes (1981) also suggested

that Triassurus sixtelae could be a larva of non-lissamphibiantemnospondyls (e.g. brachyopoids).

Unfortunately, preservation of the holotype and the onlyknown specimen of Triassurus sixtelae does not allow for adetailed comparison with larval/miniaturised non-lissamphibiantemnospondyls and stem salamanders, and pending the discov-ery of new material it is impossible to establish its precisephylogenetic position.


The basal stem salamander Kokartus honorarius is known fromthree Bathonian localities (Kyzylsu 1, Kugart 1 and Nichke 1) inthe lower part of the Balabansai Formation in Fergana Depres-sion, Kyrgyzstan (Fig. 2). Kokartus honorarius was brieflydescribed by Nesov (1988) on the basis of fragmentary cranialand postcranial bones (Nesov 1988). Subsequently, Nesov et al.(1996) presented a skull reconstruction for Kokartus based onisolated and articulated skull bones, but did not provide anyillustrations or descriptions of the actual material. Averianovet al. (2008) described numerous postcranial bones of Kokartus

Fig. 4 Salamander remains from the Early Cretaceous (Aptian–Albian) IlekFormation, Western Siberia, Russia. a, b ZIN PH 1/173, atlantal centrum ofKiyatriton leshchinskiyi (Shestakovo locality, Kemerovo Province) in ventral(a) and right lateral (b) views. c,d ZIN PH 2/173, atlantal centrum ofKiyatriton leshchinskiyi (Shestakovo locality, Kemerovo Province) in anterior

(c) and ventral (d) views. e,f ZIN PH 1/175, fragment of left maxilla ofCaudata indet (Bol’shoi Terekhtul’ 2 locality, Krasnoyarsk Region) in lateral(e) andmedial (f) views. dpDorsal process. Specimens are shown at the samemagnification


and noted that the presence of a supraglenoid foramen in thescapulocoracoid supported the basal position of KokartuswithinCaudata. Most recently, the cranial osteology of Kokartus wasredescribed using conventional methods and high-resolutioncomputed microtomography (microCT) (Skutschas and Martin2011). That study revealed the following features in Kokartus:(1) an internarial fenestra between the premaxillae; (2)overlapping of the frontal by the nasal and of the parietal bythe frontal; (3) pterygoid is dentate and bears a long, stronglyarcuate and anteromedially oriented anterior process; (4) aunique attachment of the adductor mandibulae internus to thelateral border and ventral ridge of the frontals and parietals(Skutschas and Martin 2011). Most of those newly recognisedfeatures are plesiomorphic and are known for dissorophoidtemnospondyls; the one exception is the pattern of the adductormandibulae internus attachment, which is intermediate betweennon-lissamphibian temnospondyls and salamanders. The mainprimitive features in Kokartus imply that amphibamids (includ-ing branchiosaurids) are the most closely related group to sala-manders among known non-lissamphibian temnospondyls, aconclusion that is in accordance with the widely accepted hy-pothesis of a batrachian origin from miniaturised dissorophoidtemnospondyls. Skutschas and Martin’s (2011) phylogeneticanalysis placed Kokartus in one clade with Karaurus, and thisclade (= Karauridae) was consistently placed as the sister taxonof all other salamanders.

In addition to Kokartus specimens, a caudal vertebra ofKarauridae indet. also was found in deposits of the BalabansaiFormation in Fergana Depression, Kyrgyzstan (Averianovet al. 2008). This specimen is younger (Callovian) thanKokartus honorarius and it came from the Dzhiddasai (siteFBX-23) locality in the upper part of the Balabansai Forma-tion. It is similar to that of Kokartus honorarius, but differs inhaving a notochordal perforation. This specimenmight belongto a neotenous caudate similar to Kokartus or to a metamor-phosed karaurid with a larger body than Kokartus (Averianovet al. 2008).


The principal Late Cretaceous salamander localities in MiddleAsia occur in the Khodzhakul and Bissekty formations in theKyzylkum Desert, Uzbekistan (Figs. 1 and 2). Five genera ofsalamanderswere described from those formations byLevNesov,all on the basis of isolated bones:Horezmia (Khodzhakul Forma-tion, Cenomanian); Eoscapherpeton, Mynbulakia and Bissektia(Bissekty Formation, Turonian); Nukusurus (Khodzhakul andBissekty formations) (Nesov 1981, 1997). Nukusuruswas subse-quently interpreted as an indeterminate albanerpetontid (Gardnerand Averianov 1998), and Bissektia was re-evaluated as Anuraincertae sedis (Nesov 1988). Nesov (1981) originally assignedHorezmia and Eoscapherpeton to the Scapherpetontidae (a cladeof extinct salamandroids; see Edwards 1976; Estes 1981) and

assigned Mynbulakia to the Batrachosauroididae (a clade ofextinct salamandroids; see Estes 1981; Skutschas and Gubin2012), and those assignments were widely accepted (e.g.Duellman and Trueb 1986; Holman 2006;Milner 2000; Shishkin2000). More recently, Mynbulakia was proposed to be ajunior subjective synonym of Eoscapherpeton, and a newbasal crown-group salamander genus with possiblecryptobranchoid affinities, Nesovtriton, was described on thebasis of some material previously referred to Mynbulakia andsome new material from the Bissekty Formation (Skutschas2009).

“Horezmia” and Eoscapherpeton are very similar in mor-phology, and both taxa are characterised by a unique suite ofcharacters that is not known in other salamanders: (1) presence ofa subhorizontal ridge on the external side of premaxilla andmaxilla; (2) atlas with strongly developed hypapophysis; (3)anterior trunk vertebrae with very prominent hypapophysis(Fig. 5a–d, h–k). Now that larger sample sizes are available, it isevident that most of the differences between “Horezmia” andEoscapherpeton are size related. Consequently, I consider theearly Cenomanian “Horezmia” gracile to be a species ofEoscapherpeton. Eoscapherpeton differs from scapherpetontidsby the presence of unicipital rib-bearers and the absence of spinalnerve foramen in the caudal vertebrae. It shares withcryptobranchids such characters as midline contact of the dorsal(= alary) processes of the premaxillae, frontal-maxillary contact,parietals strongly overlapped by the frontals, absence of a distinctmedial process of the pterygoid and presence of pterygoid-parasphenoid contact. Based on this suite of features,Eoscapherpeton can be referred to the Cryptobranchidae.

Although best known from the Khodzhakul and Bissektyformations, Eoscapherpeton is also known from other forma-tions in Middle Asia. Remains of salamanders of this genushave been found in the Dzharakuduk Formation (Cenomanian)and the Aitym Formation (Coniacian–Santonian), both in Uz-bekistan, and in the Yalovach Formation (Santonian) in Tajik-istan (personal observation). From the last formation, Nesov(1997) described Eoscapherpeton superum on the basis of adamaged atlantal centrum. The holotype atlantal centrum

�Fig. 5 Salamander remains from the Late Cretaceous of Middle Asia(Kyzylkum Desert, Uzbekistan): Cenomanian Khodzhakul Formation(a–d), Cenomanian Dzharakuduk Formation (e–g) and TuronianBissekty Formation (h–k). a, b ZIN PH K77-2, holotype, atlas ofEoscapherpeton gracilis (Khodzhakul locality) in anterior (a) and leftlateral (b) views. c, d ZIN PH 3/78, atlas of Eoscapherpeton gracilis(Khodzhakul locality) in anterior (c) and left lateral (d) views. e, f ZIN PH1/171, incomplete atlas of Eoscapherpeton sp. (Itemir locality) in anterior(e) and left lateral (f) views. g ZIN PH 2/171, trunk vertebra ofEoscapherpeton sp. (Itemir locality) in left lateral view. h, i ZIN PHK77-1 holotype, left maxilla of Eoscapherpeton asiaticum (Dzharakuduklocality) in lateral (h) and medial (i) views. j, k ZIN PH 16/85, atlas ofEoscapherpeton asiaticum (Dzharakuduk locality) in anterior (j) and leftlateral (k) views. hypHypapophysis, shr Subhorizontal ridge. Specimensare shown at different magnifications. Note that Eoscapherpeton graciliswas originally named “Horezmia gracile” by Nesov (1981)


exhibits the Eoscapherpeton synapomorphy of a stronglydeveloped hypapophysis, but detailed comparison with oth-er Eoscapherpeton species is impossible due to the frag-mentary nature of the specimen. A more realistic andconservative identification for the type specimen isEoscapherpeton sp. (Nesov 1988; Averianov 1999; personalobservation).

Jurassic albanerpetontids

An albanerpetontid frontal was reported from the upper part(Callovian) of the Balabansai Formation in Kyrgyzstan byNesov (1988), but this specimen was never described orfigured, and its location is unknown. As a result, this intrigu-ing report of an albanerpetontid in the Jurassic of Asia has yetto be confirmed.

Cretaceous albanerpetontids

The only unequivocal records of albanerpetontids in Asia arefrom the Cenomanian Khodzhakul and the Turonian Bissektyformations, both in the Kyzylkum Desert, Uzbekistan. Nesov(1981) described a new genus and species of albanerpetontid,Nukusurus insuetus, on the basis of fragmentary dentaries fromthe Khodzhakul Formation. In a later publication he described asecond species, N. sodalis, on the basis of a fragmentarydentary from the Bissekty Formation (Nesov 1997). Gardnerand Averianov (1998) showed that materials for the Nukusurusspecies have no diagnostic characters that can be used todistinguish these Uzbek taxa from other albanerpetontids and,accordingly, designated Nukusurus, N. insuetus and N. sodalisas nomina dubia within Albanerpetontidae.

In 2006 two fragmentary frontals were found in deposits ofthe Khodzhakul Formation, at the Khodzhakul locality. Themorphology of these specimens is similar to that ofAlbanerpetonfrontals (e.g. triangular shape in dorsal or ventral outline, shortorbital margin and relatively wide and ungrooved ventrolateralorbital crests), and those specimens were referred to that genus(Skutschas 2007). This is the first record ofAlbanerpeton outsideEurope and North America, and also the only generically iden-tifiable albanerpetontid fossils from Asia.

Kazakh record


The first Mesozoic salamander to be described from Asia wasthe basal stem salamander Karaurus sharovi, from the UpperJurassic (Kimmeridgian) Karabastau Formation in Southern Ka-zakhstan (Ivakhnenko 1978). Karaurus sharovi is known by awell-preserved, nearly complete and articulated skeleton. This isthe most anatomically complete example of a stem salamander

and, thus, it is immensely important for documenting the mor-phology of basal stem salamanders, the primitive salamandercondition, and patterns of character state transformations withinCaudata. Kokartus from the Middle Jurassic of Kyrgyzstan (seeabove) and Karaurus comprise the clade Karauridae, the mono-phyly of which is supported by only one synapomorphy—external sculpture on the skull roof formed by relatively hightubercles and short ridges (Skutschas and Martin 2011).


The first Cretaceous salamanders from Kazakhstan werereported by Nesov (1988). He noted the presence of sala-manders at two localities in the Santonian–lower CampanianBostobe Formation of the northeastern Aral Sea region:“salamanders Eoscapherpetontinae” in the Shakh-Shakh lo-cality and Eoscapherpeton sp. and a presumed prosirenid inthe Baybishe locality (Nesov 1988, p. 479, plate XVI: 12).Later, Averianov and Nessov (1995) included “salamandersScapherpetodontidae indet.” in a faunal list for the “GreyMesa” (= Alymtau 1) locality in the Campanian DarbasaFormation, Southern Kazakhstan.

In 1997, Nesov described a new albanerpetontid genus andspecies, Bishara backa, on an incomplete atlantal cenrum(Nesov 1997, p. 161, plate 10: 3), which previously had beenidentified as “presumably prosirenid” and figured by him in anearlier paper (Nesov 1988, p. 479, plate XVI: 12). One yearlater, Gardner and Averianov (1998), in their revision ofalbanerpetontids from the Late Cretaceous of Middle Asia,re-evaluated Bishara backa as an indeterminate salamander.This re-evaluation was made on the basis of the publishedphotographs (Nesov 1988, p. 479, plate XVI: 12; Nesov 1997,p. 161, plate 10: 3), because the holotype and the only spec-imen of “Bishara backa” (atlas CCMGE 240/12177) was lost(Gardner and Averianov 1998).

Expeditions to Southern Kazakhstan led by A. Averianov(in 1996 and 2012) and to the northeastern Aral Sea region ledby G. Dyke and D. Malakhov (in 2007) and by A. Averianov(in 2012) yielded isolated salamander bones from the Tulkelilocality (Turonian) in the Zhirkindek Formation and from theShakh-Shakh locality (Santonian–early Campanian) in theBostobe Formation, both in the northeastern Aral Sea region,and from the “GreyMesa” (= Alymtau 2) locality (Campanian)in the Darbasa Formation, Southern Kazakhstan.

I have been able to use these newly collected materials toevaluate previous identifications of salamanders from theBostobe and Darbasa formations and to document the presenceof salamanders in the Zhirkindek Formation. A fragmentaryprearticular and a parasphenoid from the Tulkeli locality aresimilar to those of Eoscapherpeton, but pending the discoveryof more informative specimens (e.g. maxillae, premaxillae, at-lantes and trunk vertebrae) I conservatively identify the salaman-der from the Zhirkindek Formation simply as Caudata indet.


Remains of several salamander taxa were found in theBostobe Formation (Shakh-Shakh locality). A large trunkvertebra with strongly developed hypapophysis (Fig. 6a, b)is referred to as Eoscapherpeton sp., an identification that is inaccordance with Nesov’s (1988) interpretation. An atlantalcentrum, identical with the lost holotype of Bishara backa(Nesov 1988, p. 479, plate XVI: 12; Nesov 1997, p. 161, plate10: 3), has also been collected from the Shakh-Shakh locality.This centrum (Fig. 6c–e) is relatively short anteroposteriorly,is gracile in build, has fully enclosed spinal nerve foraminaand dorsoventrally compressed anterior condyles and bearspronounced transverse processes and ventrolateral ridges.

These atlantal features are characteristic for the modernMudpuppy (Necturus), but additional material from theBostobe Formation is needed to firmly establish the proteidaffinities of “Bishara backa”. A second vertebral specimen—a small and shortened vertebral centra with bipartite transverseprocesses (= rib-bearers)—may also be assignable to “Bisharabacka”. I am currently preparing a more detailed descriptionand consideration of the relationships of “Bishara backa”.

A very small, gracile, elongate, and fragmentary trunkvertebra (Fig. 6f) recently collected from the Shakh-Shakhlocality could indicate the presence of a third salamandertaxon in the vertebrate assemblage of the Bostobe Formation.

Fig. 6 Salamander remains from the Late Cretaceous of Kazakhstan:Santonian–early Campanian Bostobe Formation (Shakh-Shakh locality,northeastearn Aral Sea region) (a–f) and Campanian Darbasa Formation[“Grey Mesa” (= Alymtau 1) locality, Southern Kazakhstan] (g–i). a–bZIN PH 1/172, fragment of trunk vertebra of Eoscapherpeton sp. inposterior (a) and right lateral (b) views. c–e ZIN PH 2/172, incomplete

atlas of “Bishara backa” in anterior (c), left lateral (d) and ventral (b)views. f ZIN PH 3/172,trunk vertebra of Caudata indet. in right lateralview. g, h ZIN PH 1/174, incomplete atlas of Eoscapherpeton sp. inanterior (g), and left lateral (h) views. i ZIN PH 2/174, incompletepremaxilla of Eoscapherpeton sp. in posterior view. hyp Hypapophysis,trpr transverse process. Specimens are shown at different magnifications


Tab

le1

Summaryof

Mesozoicsalamanderandalbanerpetontid

occurrencesin

MiddleAsia,KazakhstanandSiberia.Entries

aregroupedfrom

geologically

oldestto

youngestoccurrencesandthen

byregion

Unitand

locality

Age

Current

taxonomic

identification

(thispaper)

Previous

taxonomic

identification

Affinities

Material

Mainreferences

Low

erpartof

BalabansaiF

m.,

Kyzylsu

1,Kugart1

,Nichke1,

Fergana

Depression,

Middle

Asia,Kyrgyzstan.

Bathonian

Kokartushonorarius

Kokartushonorarius

Karauridae

(basalstem

salamanders)

Disarticulated

partialskull,

partialskullroof,isolated

completeandfragmentary

cranialand

postcranial

bones

Nesov

1988;N

esov

etal.

1996;A

verianov

etal.

2008;S

kutschas

andMartin

2011

ItatFm.,B

erezovsk

Quarry,Western

Siberia,Russia.

Bathonian

Urupiamonstrosa

Urupiamonstrosa

Basalstem

slam

ander

Anteriorfragmento

fdentary,atlantalcentra,

fragmentsof

trunk

vertebrae,femur

Skutschasand

Krasnolutskii2011

ItatFm

.,Berezovsk

Quarry,Western

Siberia,Russia.

Bathonian

“Berezovsk

salamanderA”

None

Basalstem

slam

ander

Atlantalandtrunkvertebral

centra

Thispaper

ItatFm

.,Berezovsk

Quarry,Western

Siberia,Russia.

Bathonian

“Berezovsk

salamanderB”

None

Possiblecrow

n-group

salamander

Fragm

ento

fdentary

Thispaper

Upper

partof

BalabansaiF

m.,

Dzhiddasai(siteFB

X-23),

Fergana

Depression,

Middle

Asia,Kyrgyzstan.

Callovian

Karauridaeindet.

Karauridaeindet.

Basalstem

slam

ander

Caudalv

ertebralcentra

Averianov

etal.2008

KarabastauFm.,Mikhailo

vka,

Kazakhstan.

Kim

meridgian

Karaurussharovi

Karaurussharovi

Karauridae

(basalstem

slam

anders)

Skeleton

Ivakhnenko

1978

Ilek

Fm.,Sh

estakovo,W

estern

Siberia,Russia.

Aptian-Albian

Kiyatriton

leshchinskiyi

Kiyatritonleshchinskiyi

Possible

cryptobranch-

oid

Isolated

fragmentary

cranialand

postcranial

bones

Averianov

and

Voronkevich

2002

Ilek

Fm.,Bol’shoiK

emchug

3,Western

Siberia,Russia.

Aptian-Albian

Caudataindet.

cf.K

iyatritonsp.

–Femoralfragment

Skutschas2006

Ilek

Fm.,Bol’shoiT

erekhtul’2,

Western

Siberia,Russia.

Aptian-Albian

Caudataindet.

None

–Fragmentary

maxilla

Thispaper

Dzharakuduk

Fm.,Item

ir,Kyzylkum

Desert,Middle

Asia,Uzbekistan.

Cenom

anian

Eoscapherpetonsp.“Scapherpetid

aeindet.”

Cryptobranchid

Isolated

fragmentary

cranialand

postcranial

bones

Averianov

andSu

es2007;thispaper

KhodzhakulF

m.,Khodzhakul,

Sheikhdzheili,

Kyzylkum

Desert,MiddleAsia,Uzbekistan.

Cenom

anian

Eoscapherpeton

gracilis

Horezmia

gracile

Cryptobranchid

Skull,isolated

complete

andfragmentary

cranial

andpostcranialb

ones

Nesov

1981,1988,1997

KhodzhakulF

m.,Khodzhakul,

Kyzylkum

Desert,

Uzbekistan.

Cenom

anian

Albanerpetonsp.

Nukusurus

insuetus;

Albanerpetontidae

indet.

Albanerpetontid

Fragm

entary

frontalsand

dentaries

Nesov

1981;G

ardner

andAverianov

1998;

Skutschas2007

BissektyFm.,Dzharakuduk,

Kyzylkum

Desert,Middle

Asia,Uzbekistan.

Turonian

Eoscapherpeton

asiaticum

Eoscapherpetonasiaticum

Cryptobranchid

Partialskulls,isolated

completeandfragmentary

cranialand

postcranial

bones

Nesov

1981,1988,1997


Tab

le1

(contin

ued)

Unitand

locality

Age

Current

taxonomic

identification

(thispaper)

Previous

taxonomic

identification

Affinities

Material

Mainreferences


Kyzylkum

Desert,Middle

Asia,Uzbekistan.

Turonian

Albanerpetontidae

indet.

Nukusurus

sodalis,

Albanerpetontidae

indet.

Albanerpetontid

Fragm

entary

dentaries

Nesov

1997;G

ardner

andAverianov

1998


Kyzylkum

Desert,Middle

Asia,Uzbekistan.

Turonian

Nesovtriton

mynbulakensis

Mynbulakiasurgayi,

Nesovtritonmynbulakensis

Possible

cryptobranch-

oid

Isolated

completeand

fragmentary

cranial

andpostcranialb

ones

Nesov

1981,1988;

Skutschas2009

ZhirkindekFm.,Tulkeli,

northeastearnAral

Searegion,K

azakhstan.

Turonian

Caudataindet.

None

?Fragm

entary

cranialb

ones

Thispaper

Aity

mFm.,Aity

m,

Kyzylkum

Desert,Middle

Asia,Uzbekistan.

Coniacian-

Santonian

Eoscapherpetonsp.None

Cryptobranchid

Isolated

fragmentary

cranialand

postcranial

bones

Thispaper

YalovachFm

.,Kansai,

FerganaDepression,

MiddleAsia,Tadjikistan.

Santonian

Eoscapherpetonsp.Eoscapherpetonsuperum

Cryptobranchid

Fragm

entary

atlas

Nesov

1997;thispaper

Bostobe

Fm.,Shakh-Shakh,

Baybishe,northeastearn

AralS

earegion,K

azakhstan.

Santonian-early

Cam

panian

Eoscapherpetonsp.“salam

anders

Eoscapherpetontinae”,

Eoscapherpetonsp.

Cryptobranchid

Isolated

completeand

fragmentary

cranialand

postcranialb

ones

Nesov

1988

Bostobe

Fm.,Shakh-Shakh,

Baybishe,northeastearn

AralS

earegion,K

azakhstan.

Santonian-early

Cam

panian

“Bishara

backa”

Bishara

backa

Possible

salamandroid

Atlantalcentra,fragm

entary

trunkvertebrae

Nesov

1997;thispaper

Bostobe

Fm.,Shakh-Shakh,

northeastearnAralS

earegion,K

azakhstan.

Santonian-early

Cam

panian

Caudataindet.

None

Crown-group

salamander

Fragm

entaltrunk

vertebra

Thispaper

Darbasa

Fm.,“G

reyMesa”

(=Alymtau1),

Southern

Kazakhstan.

Cam

panian

Eoscapherpetonsp.“Scapherpetodontidae

indet.”

Cryptobranchid

Isolated

completeand

fragmentary

cranial

andpostcranialb

ones

Averianov

andNessov

1995;thispaper


Salamander remains (fragmentary premaxilla, atlas andtrunk vertebrae; Fig. 6g–i) from the “Grey Mesa” (= Alymtau1) locality in the CampanianDarbasa Formation can be referredto as Eoscapherpeton sp. on the basis of such characters as asubhorizontal ridge on the external side of premaxilla and astrongly developed hypapophysis on the atlas and trunkvertebrae.

Discussion

Salamanders from the Middle Jurassic (Bathonian) of West-ern Siberia (Urupia monstrosa, “Berezovsk salamander A”and “Berezovsk salamander B”) and Kyrgyzstan (Kokartushonorarius) are among the oldest salamanders in the fossilrecord (Averianov et al. 2008; Nesov 1988; Nesov et al.1996; Skutschas and Krasnolutskii 2011; Skutschas andMartin 2011; Table 1). Other Middle Jurassic salamandersare known from the UK: Marmorerpeton kermacki; M.freemani; “Kirtlington salamander A”; “Kirtlington sala-mander B” (Evans et al. 1988; Evans and Milner 1994;Evans and Waldman 1996; Milner 2000). All of theseforms, with the exception of “Berezovsk salamander B”and “Kirtlington salamander B”, are clearly stem-groupsalamanders characterised by a relatively large body size(in comparison with Late Jurassic and Early Cretaceouscrown-group salamanders), the absence of spinal nerveforamina in the atlas and the presence of sculpture on thevertebrae. “Kirtlington salamander B” has been suggestedto be a crown-group salamander (e.g. Milner 2000), butthis assignment has not been clearly demonstrated be-cause the material remains undescribed. “Berezovsk sala-mander B” (Fig. 3n) could be a crown-group salamanderon the basis of its small size and a dentary that is lightlybuilt, lacking sculpture on its external surface and inbearing pedicellate teeth. The presence of diverse salaman-der taxa in the geographically distant Bathonian deposits ofWestern Siberia and the UK indicates that early episodes of theprimary diversification of Caudata took place before theBathonian (Skutschas and Krasnolutskii 2011). Moreover, if“Kirtlington salamander B” and/or “Berezovsk salamander B”are crown-group salamanders, then the split of Urodela (crown-group salamanders) from stem-group salamanders also tookplace well before the Bathonian; this inference is generally inaccordance with some other studies (e.g. Gao and Shubin 2012;Zang and Wake 2009).

According to data currently available on the oldest sala-manders, those Bathonian vertebrate assemblages containingsalamanders are dominated by stem-group salamanders. Atthe end of the Middle Jurassic and into the Late Jurassic,crown-group salamanders became the dominant salamandercomponent in vertebrate assemblages (e.g. Daohugou Biota inChina and the Morrison Formation in the USA), and members

of two major modern salamander clades—Cryptobranchoidea(= Cryptobranchiformes in Milner 2000) and Salamandroidea(= Salamandriformes in Milner 2000)—appeared in the fossilrecord (Evans et al. 2005; Gao and Shubin 2003, 2012; Gaoet al. 2013). Other basal stem salamanders known from thistime interval are the Kimmeridgian Karaurus sharovi fromKazakhstan, “cf. Marmorerpeton” from Portugal (Guimarotabeds), and a possible “stem salamander” from the USA (Mor-rison Formation) (Evans and Milner 1996; Gardner andDeMar 2013, this issue; Wiechmann 2000). There is no un-equivocal evidence of stem salamanders in younger deposits,which suggests they became extinct before the Jurassic–Cre-taceous boundary. The post Jurassic salamander fossil recordconsists solely of crown-group salamanders.

Early Cretaceous salamanders are known from several re-gions—Europe, Asia, North America and the Middle East(Estes 1981; Gardner and DeMar 2013; this issue; Milner2000). The discovery of the salamander Ramonellus in Israel(Middle East) is of special interest because this was the firstGondwanan occurrence of the group (Nevo and Estes 1969).The phylogenetic position of Ramonellus within Urodela isuncertain, but its elongate body and the presence of bicipitalribs (Nevo and Estes 1969) are suggestive of salamandroids;for further discussions about the affinities of this problematicgenus, the reader is advised to see Evans et al. (2005) andMilner (2000). European Early Cretaceous salamanders arerepresented by four named genera (Galverpeton, Hylaeo-batrachus,Valdotriton and Apricosiren), and a small, indeter-minate taxon with possible batrachosauroidid affinities (Estes1981; Evans and McGowan 2002; Evans and Milner 1996;Estes and Sanchiz 1982). Valdotriton (Barremian, Spain) wasoriginally referred to as Salamandroidea (Evans and Milner1996), and this assignment was accepted in some subsequentstudies (e.g. Gao and Shubin 2012; Milner 2000; Skutschasand Gubin 2012). Apricosiren (Berriasian, UK) is possiblyclosely related to Valdotriton and can be referred to asSalamandroidea on the basis of its vertebral anatomy (Evansand McGowan 2002). The possible batrachosauroidid sala-mander (Berriasian, UK) is known from the same deposits asApricosiren (Evans and McGowan 2002). Galverpeton(Barremian, Spain) exhibits vertebral characters typical forsalamandroids (e.g. opisthocoelous centrum and presence ofspinal nerve foramina) and is considered to be amember of thatclade (Milner 2000). Hylaeobatrachus (Barremian–Aptian,Belgium) has no characteristic cryptobranchoid charactersand could be tentatively referred to as Salamandroidea on thebasis of its bicipital ribs and elongate body.

The Early Cretaceous North American record of salaman-ders is limited to the Valanginian and the Aptian–Albian(Gardner and DeMar 2013, this issue). A trunk vertebra ofan indeterminate crown-group salamander has recently beenreported from the late Berriasian–Valanginian of the USA(Gardner and DeMar 2013, this issue). Aptian–Albian


salamanders in North America are known from severalgeological formations in the western USA. Indeterminatescapherpetontids, batrachosauroidids and Prosiren (aproblematic genus of crown-group salamander with pos-sible batrachosauroidid affinities; Milner 2000) have allbeen reported (e.g. Estes 1981; Gardner and DeMar 2013,this issue; Goin and Auffenberg 1958; Holman 2006;Milner 2000; Oreska et al. 2013).

Asiatic Early Cretaceous salamanders are represented byseveral taxa from the famous Jehol Biota in China (Gao et al.2013 and references therein; Wang et al. 2010; Zhang et al.2009) and byKiyatriton fromWestern Siberia (Averianov andVoronkevich 2002; this paper). Additionally, together withKiyatriton, remains of indeterminate salamanders were foundin the same geological unit (Ilek Formation) in Western Sibe-ria (Skutschas 2006, this paper). Chinese salamanders (andpossibly Kiyatriton) demonstrate cryptobranchoid featuresand could belong to this clade (Gao and Shubin 2012; Gaoet al. 2013; for alternative opinion about the phylogeneticposition of hynobiids and some salamanders from the JeholBiota, see Skutschas and Gubin 2012).

To summarise, there are regional differences in the distribu-tions of crown-group salamanders in the Early Cretaceous:cryptobranchoids were restricted to Asia, while salamandroidswere distributed in Europe, North America and northern Gond-wana (Israel); this is generally in accordance the vicariancemodelproposed by Milner (1983). However, taking into account thepresence of salamandroids in the Late Jurassic of Asia (Gao andShubin 2012) and the possible placement of hynobiids and someChinese Early Cretaceous salamanders as basal salamandroids(Skutschas and Gubin 2012), it may be necessary to invoke amore complex palaeobiogeograpical scenario than the relativelysimple vicariance model proposed by Milner (1983).

Late Cretaceous salamanders are taxonomically diverse andknown from both Laurasia (North America, Europe and Asia)and, to a much lesser extent, from Gondwana (Africa and SouthAmerica) (e.g. Estes 1981; Evans et al. 1996; Gardner 2012;Gardner and DeMar 2013, this issue; Milner 2000; Rage andDutheil 2008; Rage et al. 1993; Skutschas 2009; Szentesi et al.2013). Gondwanan salamanders (Kababisha, Noterpeton) prob-ably have sirenid affinities (Evans et al. 1996). InNorthAmerica,Late Cretaceous salamanders are represented by several extantand two extinct families: sirenids (Habrosaurus); amphiumids(Proamphiuma); proteids (Paranecturus); batrachosauroidids(Opisthotriton, Parrisia and Prodesmodon); scapherpetontids(Scapherpeton, Lisserpeton and Piceoerpeton) (e.g. DeMar2013; Estes 1981; Gardner 2012; Gardner and DeMar 2013, thisissue; Holman 2006).

The European Late Cretaceous salamander record is rela-tively poor and represented by rare, disarticulated bones.Material from the Laño locality (late Campanian–earlyMaastrichtian) in Spain is regarded as belonging to the extantfamily Salamandridae (Astibia et al. 1990), and material from

the Champ-Garimond locality (Campanian) of France hasbeen assigned to the Batrachosauroididae (Duffaud 1995).

The Late Cretaceous record of salamanders in Asia islimited to Middle Asia (Uzbekistan and Tadzhikistan) andKazakhstan and extends from the Cenomanian to Campanian(see Fig. 1; Table 1). The geologically oldest salamanders fromthis interval occur in the Cenomanian Dzharakuduk andKhodzhakul formations in Uzbekistan and are represented exclu-sively by the cryptobranchid Eoscapherpeton (Eoscapherpetonsp. in the Dzharakuduk Formation and E. gracilis in theKhodzhakul Formations) (see Table 1). The Turonian BissektyFormation (Uzbekistan) contains two salamander taxa: the possi-ble cryptobranchoid Nesovtriton mynbulakensis and thecryptobranchid Eoscapherpeton asiaticum (see Table 1), and thecontemporaneous Zhirkindek Formation (Kazakhstan) containsan indeterminate salamander (see Table 1). The Turonian–Coniacian Aitym Formation in Uzbekistan and the SantonianYalovach Formation in Tajikistan contain only the cryptobranchidEoscapherpeton sp. Salamanders in the Santonian–lower Cam-panianBostobe Formation inKazakhstan consist of three taxa: (1)the cryptobranchid Eoscapherpeton sp.; (2) a salamander withpossible proteid affinities (“Bishara backa”); (3) a small, indeter-minate salamander (see Table 1). The geologically youngest LateCretaceous salamanders in Asia are known from the CampanianDarbasa Formation in Kazakhstan and are represented by thecryptobranchid Eoscapherpeton sp.

The Cenomanian–Campanian vertebrate assemblages ofMiddle Asia and Kazakhstan are characterised by dominanceof the cryptobranchid Eoscapherpeton. Other salamanders arerare and are known only from the Turonian Bissekty Formation(the possible cryptobranchoid Nesovtriton mynbulakensis) andthe Santonian–lower Campanian Bostobe Formation (the pos-sible proteid “Bishara backa” and small indeterminate sala-mander). In a previous study (Skutschas 2009), I noted thatthere are no salamander families common to the Late Creta-ceous tetrapod assemblages of Asia and Euramerica, which is apattern that agrees with the vicariance model proposed byMilner (1983). The new material mentioned here of “Bisharabacka” could challenge that statement. If this form is a proteid,then it is significant for the following reasons: (1) it is the oldestoccurrence of that family in the fossil record (the previousoldest fossil record being in the late Maastrichtian of NorthAmerica; see DeMar 2013); (2) it is the first salamander familycommon to the Late Cretaceous tetrapod assemblages of Asiaand Euramerica; (3) it is the first extant salamandroid family inthe Late Cretaceous of Asia.

The fossil record of albanerpetontids is limited largely toEurope (Middle Jurassic–late Pliocene) and North America(Early Cretaceous–late Paleocene), with minor occurrences inNorth Africa (Early Cretaceous) and Asia (Late Cretaceous); fora summary of the albanerpetontid fossil record, see Gardner andBöhme (2008). The oldest albanerpetontids are known from theMiddle Jurassic (Bathonian) of the UK (Anoualerpeton) and


France (Albanerpetontidae indet.). In the Late Jurassic, the fossilrecord of albanerpetontids is also restricted to Europe (Celtedensand Albanerpetontidae indet. in Portugal). By the Early Creta-ceous, albanerpetontids are known from Europe (Celtedens,Wesserpeton, Albanerpeton? sp. and Albanerpetontidae indet.),North America (Albanerpeton and Albanerpetontidae indet.)and Africa (Anoualerpeton) (e.g. Gardner and Böhme 2008;Sweetman and Gardner 2013). The post-Early Cretaceous fossilrecord of albanerpetontid is limited to Europe (until the latePliocene) and North America (until the late Paleocene) andconsists solely of the genus Albanerpeton (e.g. Delfino and Sala2007; Gardner and Böhme 2008).

Asiatic albanerpetontids are known only from the Ceno-manian Khodzhakul (Albanerpeton sp.) and the TuronianBissekty (Albanerpetontidae indet.) formations in the KyzylkumDesert, Uzbekistan (Gardner and Averianov 1998; Skutschas2007). The identification of Albanerpeton in the KhodzhakulFormation indicates this genus was broadly distributed duringthe Late Cretaceous across Laurasia, with occurrences in westernEurope, western North America and Asia. In contrast to Europeand North America, albanerpetontids are extremely rare compo-nents of the Late Cretaceous Asiatic local vertebrate assem-blages; the reason for this rarity is unclear (Skutschas 2007).

Future work

Discoveries of salamanders and albanerpetontids in Jurassic andCretaceous deposits in Middle Asia, Kazakhstan and Siberia arestarting to fill geographic and temporal gaps in the fossil recordsfor those groups and, thus, are improving our understanding ofsome aspects of their early evolution. Nevertheless, we still knowvery little about Mesozoic salamanders and albanerpetontidsfrom these regions, and this situation will not improve signifi-cantly until new localities and specimens are discovered. I hopethat future work in Middle Asia, Kazakhstan and Siberia willevolve in several directions. The first task is to search for pre-Bathonian stem salamanders and Jurassic albanerpetontids. Thesecond task is to continue collecting and studying Bathoniansalamanders. The third task is to continue searching for Creta-ceous salamanders and albanerpetontids in Middle Asia, Ka-zakhstan and Siberia and also to extend this search into otherAsiatic territories (e.g. Mongolia and Russian Far East). Thesefield programs hopefully will yield new specimens that willprove informative for resolving patterns of interrelationshipsamong lissamphibian groups (salamanders, frogs, caeciliansand albanerpetontids) and for documenting primitive condi-tions and patterns of character state transformations. Thesenew specimens also could help us better understand the earlyevolution of crown-group salamanders and interpret thepalaeobiogeography and palaeobiology of Mesozoic salaman-ders and albanerpetontids.

Acknowledgements I thank all the members of expeditions in MiddleAsia, Kazakhstan and Siberia for their help. I am grateful to: J. D. Gardner(Royal Tyrrell Museum, Drumheller, Canada) for organising the sympo-sium “Insights from the Fossil Record into the Evolution of ExtantAmphibians and Reptiles” at the SeventhWorld Congress of Herpetologyin Vancouver, Canada, and for his invitations to visit the Royal TyrrellMuseum and to contribute this issue; to the Royal Tyrrell MuseumCooperating Society (Drumheller, Canada) for providing financial sup-port for my visit to the Royal Tyrrell Museum; to A. O. Averianov(Zoological Institute, Russian Academy of Sciences, St. Petersburg,Russia) for reading and providing helpful comments on an early versionof this paper; and to J. D. Gardner (Royal Tyrrell Museum, Drumheller,Canada) and A. R. Milner (Natural History Museum, London, UK) forreviewing the submitted version of this paper. My studies of Mesozoicsalamanders have been funded by the following agencies and grants: theDeutsche Forschungsgemeinschaft (DFG) grant MA 1643/14-1 and theRussian Foundation for Basic Research (project 11-04-91331-NNIO) forstudies of Siberian Middle Jurassic salamanders; a Postdoctoral ResearchFellowship and a Return Fellowship of the Alexander von Humboldt-Foundation (Germany) for study of Kokartus; a Return Fellowship of theAlexander von Humboldt-Foundation(Germany) and the PaleontologicalSociety International Research Program (Sepkoski Grants 2010) (USA)for studies of Middle Asian Late Cretaceous salamanders.

References

Anderson JS, Reisz RR, Scott D, Fröbisch NB, Sumida SS (2008) A stembatrachian from the Early Permian of Texas and the origin of frogsand salamanders. Nature 453:515–518

Astibia H, Buffetaut E, Buscalioni AD, Cappetta H, Corral C, Estes R,Garcia-Garmilla F, Jaeger JJ, Jimenez-Fuentes E, Le Loeuff J,Mazin JM, Orue-Etxebarria X, Pereda-Suberbiola J, Powell JE,Rage J-C, Rodriguez-Lazaro J, Sanz JL, Tong H (1990) The fossilvertebrates from Laño (Basque Country, Spain); new evidence onthe composition and affinities of the Late Cretaceous continentalfaunas of Europe. Terra Nova 2:460–466

Averianov AO (1999) Annotated list of taxa described by L. A. Nesov (inRussian). Trudy Zoologicheskogo Instituta RAN 277:7–37

Averianov AO, Nessov LA (1995) A new Cretaceous mammal from theCampanian of Kazakhstan. N Jb Geol Paläont, Mh 1995:65–74

Averianov AO, Sues H-D (2007) A new troodontid (Dinosauria:Theropoda) from the Cenomanian of Uzbekistan, with a review oftroodontid records from the territories of the former Soviet Union. JVertebr Paleontol 27:87–98

Averianov AO, Sues H-D (2012) Correlation of Late Cretaceous conti-nental vertebrate assemblages in Middle and Central Asia. J Stratigr36:462–485

Averianov AO, Voronkevich AV (2002) A new crown-group salamanderfrom the Early Cretaceous of Western Siberia. Russ J Herpetol9:209–214

Averianov AO, Lopatin AV, Skutschas PP, Martynovich NV, LeshchinskiySV, Rezvyi AS, Krasnolutskii SA, Fayngerts AV (2005) Discovery ofmiddle Jurassic mammals from Siberia. Acta Palaeontol Pol 50:789–797

Averianov AO, Martin T, Skutschas PP, Rezvyi AS, Bakirov A (2008)Amphibians from theMiddle Jurassic Balabansai Svita in the FerganaDepression, Kyrgyzstan (Central Asia). Palaeontology 51:471–485

BentonMJ (2000) Conventions in Russian andMongolian palaeontologicalliterature. In: Benton MJ, Shishkin MA, Unwin DM, Kurochkin EN(eds) The age of dinosaurs in Russia and Mongolia. CambridgeUniversity Press, Cambridge, pp xvi–xxxix

Delfino M, Sala B (2007) Late Pliocene Albanerpetontidae (Lissamphibia)from Italy. J Vertebr Paleontol 27:716–719


DeMar D (2013) A new fossil salamander (Caudata: Proteidae) from theUpper Cretaceous (Maastrichtian) Hell Creek Formation, Montana.J Vertebr Paleontol 33:588–598

Duellman WE, Trueb L (1986) Biology of amphibians. McGraw-Hill,New York

Duffaud S (1995) A Batrachosauroididae (Amphibia, Caudata) from thelate Cretaceous of Champ-Garimond (Southern France). First Euro-pean Workshop on Vertebrate Paleontology, Geological Society ofDenmark, DGF On Line Series 1. Available at: http://2dgf.dk/publikationer/dgf_on_line/vol_1/duffaud.html. Accessed 6 Aug 2010

Edwards J (1976) Spinal nerves and their bearing on salamander phylo-geny. J Morphol 148:305–327

Estes R (1981) Encyclopedia of paleoherpetology. Part 2A, Gymnophiona,Caudata. Gustav Fischer Verlag, Stuttgart

Estes R, Sanchiz B (1982) Early Cretaceous lower vertebrate from Galve(Teruel), Spain. J Vertebr Paleontol 2:21–39

Evans SE, McGowan GJ (2002) An amphibian assemblage from thePurbeck Limestone Group. Spec Pap Palaeontol 68:103–119

Evans SE, Milner AR (1994) Microvertebrate faunas from the MiddleJurassic of Britain. In: Fraser N, Sues HD (eds) In the shadow of thedinosaurs: early Mesozoic tetrapods. Cambridge University Press,Cambridge, pp 303–321

Evans SE, Milner AR (1996) A metamorphosed salamander from theEarly Cretaceous of Las Hoyas, Spain. Phil Trans Roy Soc Lond B351:627–646

Evans SE, Waldman M (1996) Small reptiles and amphibians from theMiddle Jurassic of Skye, Scotland. Mus North Ariz Bull 60:219–226

Evans SE, Milner AR, Mussett F (1988) The earliest known salamanders(Amphibia, Caudata): a record from theMiddle Jurassic of England.Geobios 21:539–552

Evans SE, Milner AR, Werner C (1996) Sirenid salamanders and agymnophionan amphibian from the Cretaceous of the Sudan.Palaeontology 39:77–95

Evans SE, Lally C, Chure DC, Maisano JA (2005) A Late Jurassicsalamander (Amphibia: Caudata) from the Morrison Formation ofNorth America. Zool J Linn Soc 143:599–616

Gao K-Q, Shubin NH (2003) Earliest known crown-group salamanders.Nature 422:424–428

Gao K-Q, Shubin NH (2012) Late Jurassic salamandroid from westernLiaoning, China. Proc Natl Acad Sci. doi:10.1073/pnas.1009828109

Gao K-Q, Chen J, Jia J (2013) Taxonomic diversity, stratigraphic range,and exceptional preservation of Juro-Cretaceous salamanders fromnorthern China. Can J Earth Sci 50:255–267

Gardner JD (2001) Monophyly and affinities of albanerpetontid amphib-ians (Temnospondyli; Lissamphibia). Zool J Linn Soc 131:309–352

Gardner JD (2012) Revision of Piceoerpeton Meszoely (Caudata:Scapherpetontidae) and description of a new species from the lateMaastrichtian and ?early Paleocene of western North America. BullSoc Géol France 183:611–620

Gardner JD, Averianov AO (1998) Albanerpetontid amphibians fromMiddle Asia. Acta Palaeontol Pol 43:453–467

Gardner JD, Böhme M (2008) Review of the Albanerpetontidae(Lissamphibia), with comments on the paleoecological preferencesof European Tertiary albanerpetontids. In: Sankey JT, Baszio S (eds)Vertebrate microfossil assemblages: their role in paleoecology andpaleobiogeography. Indiana University Press, Bloomington, pp 178–218

Gardner JD, DeMar DG Jr (2013)Mesozoic and Paleocene lissamphibianassemblages of North America: a comprehensive review. In: Gard-ner J, Nydam RL (eds) Mesozoic and Cenozoic lissamphibian andsquamate assemblages of Laurasia. Palaeobio Palaeoenv 93(4).doi:10.1007/s12549-013-0130-z

Goin CJ, Auffenberg W (1958) New salamanders of the family Sirenidaefrom theCretaceous ofNorthAmerica. Fieldiana: Geology 10:449–459

Holman JA (2006) Fossil salamanders of North America. Indiana Uni-versity Press, Bloomington

Ivakhnenko M (1978) Urodeles from the Triassic and Jurassic of SovietCentral Asia. Palaeontol Zhur 1978:84–89 (in Russian) and PaleontolJ 1978:362–368 (in English)

Marjanović D, Laurin M (2008) A reevaluation of the evidencesupporting an unorthodox hypothesis on the origin of extant am-phibians. Contrib Zool 77:149–199

Milner AR (1983) The biogeography of salamanders in theMesozoic andEarly Caenozoic: a cladistic–vicariance model. In: Sims RW, PriceJH, Whalley PES (eds) Evolution, time and space: the emergence ofthe biosphere, Systematics Assoc Spec 23:431–468

Milner AR (2000) Mesozoic and tertiary Caudata and Albanerpetontidae.In: Heatwole H, Carroll RL (eds) Amphibian biology, vol. 4.Palaeontology. Surrey Beaty, Chipping Norton, pp 1413–1444

Nesov LA (1981) Cretaceous salamanders and frogs of Kizylkum Desert(in Russian). Proc Zool Inst AS USSR 101:57–88

Nesov LA (1988) Late Mesozoic amphibians and lizards of SovietMiddle Asia. Act Zool Cracovienska 31:475–486

Nesov LA (1997) Cretaceous nonmarine vertebrates of Northern Eurasia(in Russian). Posthumous edition by Golovneva LB, AverianovAO.Izdatel’stvo Sankt-Peterburgskogo Universiteta, Saint Petersburg

Nesov LA, Fedorov PV, PotapovDO,Golovnyeva LS (1996) The structureof the skulls of caudate amphibians collected from the Jurassic ofKirgizstan and the Cretaceous of Uzbekistan (in Russian). VestnikSankt-Petersburgskogo Universiteta, Seriya 7, Geologiya, Geografiya1:3–11

Nevo E, Estes R (1969) Ramonellus longispinus, an Early Cretaceoussalamander from Israel. Copeia 1969:540–547

Oreska MPJ, Carrano MT, Dzikiewicz KM (2013) Vertebrate paleontologyof the Cloverly Formation (Lower Cretaceous), 1: faunal composition,biogeographic relationships, and sampling. J Vertebr Paleontol 33:264–292

Rage J-C, Dutheil D (2008) Amphibians and squamates from the Creta-ceous (Cenomanian) ofMorocco. Palaeontographica Abt A 285:1–22

Rage J-C, Marshall LG, Gayet M (1993) Enigmatic Caudata (Amphibia)from the Upper Cretaceous of Gondwana. Geobios 26:515–519

Ruta M, Coates MI (2007) Dates, nodes and character conflict: address-ing the lissamphibian origin problem. J Syst Palaeontol 5:67–122

Shishkin MA (2000) Mesozoic amphibians from Mongolia and thecentral Asian republics. In: Benton MJ, Shishkin MA, Unwin DM,Kurochkin EN (eds) The age of dinosaurs in Russia and Mongolia.Cambridge University Press, Cambridge, pp 297–308

Sigurdsen T, Green DM (2011) The origin of modern amphibians: a re-evaluation. Zool J Linn Soc 162:457–469

Skutschas PP (2006) Mesozoic amphibians from Siberia, Russia. In: BarrettPM, Evans SE (eds) 9th Int Symp onMesozoic Terrestrial Ecosystemsand Biota. Abstracts and Proceedings Volume, pp 123–126

Skutschas PP (2007) New specimens of albanerpetontid amphibians fromtheUpper Cretaceous of Uzbekistan. Acta Palaeontol Pol 52:819–821

Skutschas PP (2009) Re-evaluation of Mynbulakia Nesov, 1981(Lissamphibia: Caudata) and description of a new salamander genusfrom the Late Cretaceous of Uzbekistan. J Vertebr Paleontol 29:1–6

Skutschas PP, Gubin YM (2012) A new salamander from the late Paleo-cene–early Eocene of Ukraine. Acta Palaeontol Pol 57:135–148

Skutschas PP, Krasnolutskii SA (2011) A new genus and species of basalsalamanders from the Middle Jurassic of Western Siberia, Russia.Proc Zool Inst RAS 315:167–175

Skutschas P, Martin T (2011) Cranial anatomy of the stem salamanderKokartus honorarius (Amphibia: Caudata) from theMiddle Jurassicof Kyrgyzstan. Zool J Linn Soc 161:816–838

Sweetman SC, Gardner JD (2013) A new albanerpetontid amphibianfrom the Early Cretaceous (Barremian) Wessex Formation of theIsle of Wight, southern England. Acta Palaeontol Pol 58:295–324

Szentesi Z, Gardner JD, Venczel M (2013) Albanerpetontid amphibiansfrom the Late Cretaceous (Santonian) of Iharkút, Hungary, withremarks on regional differences in Late Cretaceous Laurasian am-phibian assemblages. Can J Earth Sci 50:268–281


http://2dgf.dk/publikationer/dgf_on_line/vol_1/duffaud.html

http://2dgf.dk/publikationer/dgf_on_line/vol_1/duffaud.html

http://dx.doi.org/10.1073/pnas.1009828109

http://dx.doi.org/10.1007/s12549-013-0130-z

Wang Y, Dong LP, Evans SE (2010) Jurassic-Cretaceous herpetofaunasfrom the Jehol associated strata in NE China: evolutionary andecological implications. Bull Chin Acad Sci 24:76–79

Wiechmann MF (2000) The albanerpetontids from the Guimarota mine.In: Martin T, Krebs B (eds) Guimarota: a Jurassic ecosystem. VerlagDr. Friedrich. Pfeil, Munich, pp 51–54

Zang P, Wake DB (2009) Higher-level salamander relationships anddivergence dates inferred from complete mitochondrial genomes.Mol Phylogenet Evol 53(2009):492–508

Zhang G, Wang Y, Jones MEH, Evans SE (2009) A new Early Cretaceoussalamander (Regalerpeton weichangensis gen. et sp. nov.) from theHuajiying Formation of northeastern China. Cretaceous Res 30:551–558


mesozoic salamanders and albanerpetontids of middle asia, kazakhstan, and siberia

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