Osteology of Russian Toads and Frogs for Paleontological Researches

Acta zoologica cracoviensia, 44(1): 1-23, Krakow, 30 March, 2001

Osteology of Russian toads and frogs for paleontological researches

V RATNIKO . Yu v Viatchesla

Received: 24 May, 2000 Accepted for publication: 28 Dec., 2000

RATNIKOV V. Yu. 2001. Osteology of Russian toads and frogs for paleontological researches. Acta zoologica cracoviensia, 44(1): 1-23. Abstract. Osteological diagnosis of modern genera Bufo and Rana as well as species Bufo bufo, B. gargarizans, B. verrucosissimus, B. viridis, B. raddei, B. calamita, Rana temporaria, R. chensinensis, R. arvalis, R. asiatica, R. amurensis, R. ridibunda, R. lessonae and R. nigromaculata are given. The genera investigated are distinguished very easily, because practically all the skeletal elements, with the exception of distal elements of the limbs, have their specific generic features. Bufonids have 9-11 bones used for species identification. The most important of them are ilium, frontoparietale, maxillare, and parasphenoideum. Ranids have 6-7 such bones, the most important of which are ilium, frontoparietale, and scapula. . Russia , species n Moder Rana, Bufo, , Osteology : words y Ke Viatcheslav Yu. RATNIKOV, Geological Faculty, Voronezh State University, University Sq. 1, Voronezh, 394693 Russia. E-mail: [email protected]

I. INTRODUCTION The geological researches of anhtropogenic deposits of the East-European platform conducted recently, have shown, that amphibian and reptile remains in them occur not so rarely as had been previously supposed. As a part of fossil fauna, they bear information concerning the geological past and can be used for the reconstruction of paleogeographical conditions and the determination of the geological age of bone-bearing deposits (RATNIKOV, 1995, 1996a). Most of the remains in quater- nary sediments belong to modern species, requiring their careful study for comparison with fossil materials. Paleontologists should also take into consideration the change of systematic status of some forms in connection with the new ideas of the neoherpetologists and finding osteological distinctions in newly described species. In the present paper the author brings criteria of identification of skeleton elements of some modern representatives of genera Bufo and Rana, which are often found in anthropogene deposits of Russia. He found these criteria when comparing the fossil remains with samples of osteological collection, which contains (sensu BORKIN, DAREVSKY, 1987) (the digits denote the number of specimens): Bufo bufo (LINNAEUS) -21, Bufo verrucosissimus PALLAS - 8, V. Yu. RATNIKOV 2

, 9 - R CANTO gargarizans Bufo Bufo viridis LAURENTI - 14, Bufo raddei STRAUCH - 12, , 3 - I LAURENT calamita Bufo Rana temporaria LINNAEUS - 10, , —11 D DAVI chensinensis Rana Rana arvalis NlLSSON - 37, , 6 - A BEDRIAG asiatica Rana , 6 - R BOULENGE amurensis Rana , 19 - S PALLA ridibunda Rana Rana lessonae CAMERANO - 8, Rana nigromaculata HALLO WELL - 6. g describin s article n i d mentione y rarel y ver e ar s bone g fro d an d toa f o s attribute c generi e Th fossil finds. Some information is contained in the works of BOHME, 1977; HOLMAN, 1998; RAGE, 1974, but it is not complete. Therefore the present author gives a criterion of the generic identification he used, and where possible avoids mention data from those papers. He used the terminology of the above-mentioned authors and given by SANCHIZ (1998). Acknowledgements. The author thanks Prof. Z. ROCEK for examination of e th g translatin n i p hel r he r fo A L.TlTOV o t l grateful o als s i e h d an s remark e valuabl d an r pape s thi work in to English. This study was possible thanks to L. BORKTN, A. MASALYKIN, and V. ORLOVA . collection l osteologica e th e complet o t r autho e th d helpe o wh

II. FAMILY BUFONIDAE Genus Bufo LAURENTI, 1768 Condylus occipitalis is wide, with parallel lateral margins; the borders of fossa condyloidea practically coincide with those of foramen jugulare (Fig. 1 A, B). Small and large openings of the - Na . dimentions r simila e hav d an r othe h eac o t e clos y ver e ar l cana r semicircula r anterio t shor y ver sale are of subtriangular form or with a small S-shaped bend (Fig. 2 C-F). Pars lateralis ossis squa- n tha r wide s i i parasphenoide s Corpu . C-H) 4 . (Fig s zygomaticu s ramu o t e angl e acut n a t a s i mosi lateral processes, the length of the bone being less than the distance between the ends of lateral processes (Fig. 3 A-F). Two blades of the anterior pterygoid branch coincide in width along the greater s i e Gonial . A) 4 . (Fig e blad l ventra e th n o n projectio d angle-shape n a s i e ther d an , length s it f o t par comparatively high, with low processus coronoideus considerably deviated laterally; dorsal margin s i e bon e th f o t par r posterio ; process d coronoi a r unde s end h whic , crest a s a s proceed e bon e th f o abruptly curved in S manner, the lateral margin forms a visible obtuse angle; the ventral part of the bone under the coronoid process is considerably compressed but does not form a crest; channel for o tw n betwee e spac e som s i e Ther . O) 4 . (Fig e bon e th f o t par e middl e th n i s i e cartilag i Mekkel cotyles of atlas; neural arch in the upper part is very thick (Fig. 5 A-B). Vertebrae with large, often compressed bodies; the neural arch is massive in the upper part at breast vertebras and is flattened dorsally at abdominal ones, being almost in the same plane with diapophises; canalis neuralis of abdominal vertebrae is narrow especially at presacral vertebra (Fig. 5 D, E, H, I). Joint pits of urostyl - ven ; view r anterio n i e triangl l equilatera n a f o m for g havin , low s i l channe l neura ; separated t no e ar - widen e considerabl h wit y usuall , medially s widen Clavicula . E) 6 . (Fig x conve s i e surfac e bon l tra ing on the lateral end (Fig. 6 G-J). Cleithrum is of V-shape; the posterior margin of lamina marginalis cleithri, approaching margo scapularis, turns in caudal direction, forming subtriangular expansion of l.marginalis (Fig. 6 L). Pars acromialis and pars glenoidalis of scapula do not cover s frog d an s toad n Russia f o y Osteolog

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- prooti - E D- temporaria; Rana - C viridis, Bufo - B bufo, Bufo - A : view r posterio , exoocipital - C A- . bones l Crania . 1 . Fig cum, dorsal and ventral views: D - Rana temporaria, E - Rana ridibunda; F-L - maxillare, F-H, K, L - outer view, I-J - in- Bufo — K raddei, Bufo - } viridis, Bufo - I verrucasissimus, Bufo - H gargarizans, Bufo - G bufo, -F Bufo : view r ne - N bufo, Bufo - M : views ) anterior d an - P , M , (J l ventra , dorsal , sphenethmoideum - S M- arvalis; Rana - L calamita, temporaria. Rana - S calamita, Bufo - R raddei, Bufo - Q viridis, Bufo - P verrucosissimus, Bufo - O gargarizans, Bufo V. Yu. RATNIKOV

, nasale - G C- ; view l dorsa temporaria, Rana - B ; view r anterio viridis, Bufo - A : praemaxillare - B A- . bones l Crania . 2 . Fig dorsal view Bufo- C : bufo, Bufo- D viridis, E—Bufo raddei, —F Bufo calamita, Rana- G temporaria; H-U frontoparie- - tale, dorsal view: H - Bufo bufo (fused with prooticum and exoccipitale), 1 - Bufo gargarizans (fused with prooticum), J - Bufo verrucosissimus, K - Bufo viridis (fused with prooticum), L - Bufo raddei (fused with prooticum and exoccipitale), M - Bufo calamita (fused with prooticum and exoccipitale), N - Rana temporaria, O - Rana chensinensis, P - Rana arvalis, Q - Rana asiatica, R - Rana amurensis, S - Rana ridibunda, T — Rana lessonae, U - Rana nigromaculata. Osteology of Russian toads and frogs

- E viridis, Bufo - D verrucosissimus, Bufo - C gargarizans, Bufo - B bufo, Bufo - A . view l ventra , Parasphenoideum . 3 . Fig Bufo calamita, Bufo- F raddei, Rana- G temporaria, Rana- H chensinensis, Rana- I arvalis, —J .Sara asiatica,K San- N anigromaculata. San- M alessonae, ffa«- L aridibunda, Xa«aamurensis, V. Yu. RATNIKOV

- C : view r oute , squamosum - P C- arvalis; Rana — B bufo, Bufo - A : view r oute , pterygoideum - A-B . bones l Crania . 4 . Fig Bufo bufo, D - Bufo gargarizans, E — Bufo verrucosissimus, F — Bufo viridis, G - Bufo raddei, H — Bufo calamita, I — ridibunda, ^- f ana N amurensis, a Ran M— asiatica, Rana - L chensinensis, Rana - K temporaria, Rana - J arvalis, Rana arvalis. -R Rana bufo, Bufo - Q : views l interna d an l dorsa , goniale - R Q- nigromaculata; Rana - P lessonae, Rana - O Osteology of Russian toads and frogs

- G D- temporaria; Rana - C viridis, Bufo - B bufo, Bufo - A : views r posterio d an r anterio , atlas - C A- . Vertebrae . 5 . Fig - D : views r anterio d an l ventra , dorsal - G , views l ventra d an l dorsa - F , views r anterio d an l dorsa - E D- , vertebra t breas Bufo bufo, E—Bufo viridis, F - Rana temporaria, G — Rana ridibunda; H-L — abdominal vertebra, H-I - dorsal and anterior -J Rana viridis, Bufo - I bufo, Bufo - H : views l ventra d an l dorsa - L K- , views r anterio d an l ventra , dorsal - J , views arvalis. Rana - L temporaria, Rana - K ridibunda, V. Yu. RATNIKOV

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Fig. 6. A-D - sacrum, A-B - dorsal and anterior views, C-D - dorsal view: A- Bufo bufo, B - Bufo viridis, C - Rana temporaria, D - Rana ridibunda; E-F - urostyl, anterior and lateral views: E - Bufo bufo, F - Rana temporaria; G-K - clavicula, internal view: G - Bufo gargarizans, H - Bufo viridis, I - Bufo raddei, J - Bufo calamita, K — Rana arvalis; L-M - clei- Rana - P O- gargarizans, Bufo - N : view r inne , coracoideum - P N- arvalis; Rana - M viridis, Bufo - L : view r inne , thrum temporaria: O - male, P - female. s frog d an s toad n Russia f o y Osteolog

each other; facies lunata is turned laterally; crista longitudinalis is weakly expressed (Fig. 7 A-F). ; medialis s extremita f o t tha o t l equa y approximatel s i i coracoide s laterali s extremita f o h widt e Th n olecrano f o s axi e Th . N) 6 . (Fig d rounde y slightl r o t straigh r eithe s i e bon e th f o n margi l media s crest l ventra e thre o t p u e b y ma e ther ; humerus f o s axi g lon o t y relativel y laterall d displace s i e trac e middl e th n o y approximatel s i h widt m ischiu t greates e Th . 8) . (Fig e bon e th f o f hal l proxima a n o line; the area for attachment of hind limb muscles is wide (Fig. 12 A). Crus is short, sharply widened a s ha n ofte , compressed ) nutritium n forame f o n regio e th n (i t par e middl e th n i , ends e th s toward s les r o e mor d en l dista e th t a a fibul d an a tibi f o s section ; sides h bot m -y fro rarel , side a tibi m fro l kie h muc s i d en l dista e th n o n sectio a tibi f o r diamete e th ; oval e ar y the d en l proxima e th t a , rounded smaller than that of the fibula one, whereas on the proximal end they are approximately equal; near the foramen nutritium, close to the distal bone end, there is a deep furrow, turning into sulcus inter- s i s bone d toa f o y majorit e th f o s characteristic l additiona e Th . J) 2 1 . (Fig n directio l dista n i s mediu specific "toad" shading which is absent in other modern Anura of Russia. s toad e pleistocen f o s feature s specie f o n estimatio e th o t devoted e ar s work f o r numbe A e thes l Al . 1977) , SANCHIZ ; 1989,1998 , HOLMAN ; 1980 , HODROVA ; 1977 , BOHME ; 1986 , (BAILON researches are based on the assumption that the same three modern toad species existed in Western - diag n i e acceptabl t no s i n assumptio s Thi viridis. B. d an calamita, B. bufo, Bufo : past e th n i e Europ - subspe r forme f o e transferenc f o y tendenc e th , Firstly . material l fossi e Europ n Easter e th f o s nostic cies to species has made it necessary to search for identification criteria of new species and revision of old ones, concerning first of all B. bufo. Secondly, the present author has admitted the possibility of occurence in anthropogene deposits not only forms living these at present, that has later proved to be true (RATNIKOV, 1996b). Thus, the number of possible levels of fossil material determination has increased. The modern representatives of genus Bufo of Eurasia are united by zoologists in unsystematic groups (complexes) on the basis of certain attributes. The toads of Russia and adjacent countries form two complexes: Bufo (bufo) sp. (the grey toad group) and Bufo (viridis) sp.(the green toad group). Representatives of each complex have similar features in the structure of some skeleton - at l ecologica r simila d an , complex r anothe f o s representative m fro m the g distinguishin , elements e th g durin s condition l paleogeographica e th f o n reconstructio r fo t importan y ver s i h whic , tachment . 1996a) , (RATNIKOV y localit e th f o n formatio Bufo (bufo) sp. - Eleva . A) 1 . (Fig h hig d an w narro y usuall s i s terminali s toru ; wide y ver s i s occipitali s Condylu tio prootici is well expressed and is disposed along the anterior margin of the bone; ramus lateralis w narro h wit y usuall s i d Sphenethmoi . I) , H 2 . (Fig y laterall d unnarrowe t almos , massive s i i prootic . M-O) 1 . (Fig s cavitie r thei n i s fold d expresse y weakl d an i olfactori s canali f o s opening r posterio The anterior end of maxilla pars facialis as a process projects forward further than anterior end of y graduall e Frontoparietal . C) 2 . (Fig d ben d S-shape e visibl s ha e Nasal . F-H) 1 . (Fig s dentali s par narrows in the anterior part; dorsal surface is flattened and is not limited by crest; lateral margin of the bone is abruptly curved downwards (Fig. 2 H-J). Squamosum has considerably widened ramus - re n i d ben t abrup s form i parasphenoide s corpu f o e surfac l Ventra . C-E) 4 . (Fig s retrozygomaticu gion of lateral processes and has more abrupt relief than representatives of Bufo (viridis) sp. do l ova e ar s vertebra t breas f o a Centr . A) 5 . (Fig e condyl l ova d an s cotyle e wid s ha s Atla . A-C) 3 . (Fig in cross section; cotyles at abdominal vertebrae acquire a half-moon form; dorsal plane of neural arch as a rule is longer than ventral one; diapophises widened at the basis and compressed (Fig. 5 D, H). Sacral neurapophyses are of wide A-shaped form (Fig. 6 A). Humerus has usually more convex comparatively s i i ili s ossi a Al . toads n gree f o s representative o d n tha d en l dista e th n o e surfac l dorsa thick without pre-acetabular pit; subtriangular form is characteristic for the bone body (Fig. 10 . C-E) 2 1 . (Fig s femori a crist t shor y comparativel h wit r Femu . A-C) It was considered that only one species from the group of grey toads - Bufo bufo (L.) with sev- eral subspecies - existed on the territory of the former USSR (BANNIKOV et al., 1977). Not long ago V. Yu. RATNIKOV

herpetologists acknowledged the independence of a Far Eastern subspecies, which is now included into the structure of Bufo (bufo) sp. under the species name Bufo gargarizans CANTOR (BORKIN, n notyetbee s ha s subspecie n Caucasia e th f o n positio c systemati f o n questio e Th . 1987) Y DAREVSK , 1989) V TUNIE , (ORLOVA s specie t independen n a t i r conside s herpetologist e Som . solved y finall whereas others (GUNTHER 1985) are of the opinion that only one species exist in Europe. V. M. e th f o e independenc d an y osteolog n i s difference f o e existenc e th o t d pointe ) (1984 E CKHIKVADZ Caucasian toad. The materials investigated by the present author show that the level of differences between B. bufo and 5. gargarizans is the same as that between B. bufo and B. bufo verrucosissimus. verrucosissimus cf. B. r o verrucosissimus B. s a s bone l fossi e som d identifie e therefor s ha e H (RATNIKOV 1992). In the last list of the former USSR herpetofauna (ANANJEVA et al. 1998) Bufo verrucosissimus is given as a species. In that work the description of osteological features of three grey toad species - Bufo bufo (L.), Bufo gargarizans CANTOR and Bufo verrucosissimus (PALL.) - is adduced.

) 1758 , (LINNAEUS bufo Bufo d expresse y weakl g bein m the n o s crest l ventra , short e ar m sphenethmoideu f o s processe l Latera - un s i a palatin s par f o s proces r posterio ; folds t withou e maxillar f o e surfac l Externa . M) 1 . (Fig derdeveloped, not projecting over the upper margin of pars facialis (Fig. 1 F). Frontoparietale gently narrowed toward the anterior end; facies cerebralis posterior are of elliptic form with a long axis almost perpendicular to margo sagittalis of the bone (Fig. 2 H). Ramus zygomaticus ossis squamosi is usually short; margins of ramus retrozygomaticus are parallel or slightly divergent, the upper margin often with wavy bend (Fig. 4 C). Lateral processes and corpus parasphenoidei are of equal g recallin t cres d well-define a s i e ther s procese l latera f o n regio n i e bon e th f o e lin l axia n a n o ; width a "tick" in its outlines; straight lateral margins of the bone body that one abruptly bent turn into anterior margins of lateral processes; posterior process is usually narrow (Fig. 3 A). Scapula with comparatively wide head and narrow neck; the anterior margin of pars acromialis may be stretched in e th f o e middl e th h reac t no s doe y usuall s humeru f o t cres l Media . A) 7 . (Fig s acromiali s tenuita bone, it is wide, with rounded margin, slightly deviated dorsally; spina medialis dorsalis can be ob- t bu w lo n ofte s ha m Iliu . A) 8 . (Fig e noticabl barely s i s ventrali s mediali a spin s wherea , served sometimes high tuber superior on which as a rule there is one large tubercle often displaced forward (Fig. 10 A). Femur has a single crista femoris; there is sometimes an additional obtuse crest in large specimens, which begins not far from the distal end of crista femoris (Fig. 12 C).

2 184 , CANTOR gargarizans Bufo The posterior part of ventral sphenethmoid area is wide; lateral processes are rather long with abrupt ventral crests (Fig. 1 N). Smooth fold is visible on external surface of maxillare from the an- s par f o n margi r uppe e th r ove t projec t no s doe t almos a palatin s par f o s proces r posterio ; end r terio facialis (Fig. 1 G). Lateral margin of frontoparietale is as a rule weakly bent in an arch-like manner; facies cerebralis posterior is practically round (Fig. 2 I). Ramus zygomaticus osis squamosi is usu- appreciabls e ydiverg retrozygomaticu s ramu f o s margin e th d an , thin d an g lon y comparativel y all - cor f o s margin l latera d convexe ; process l latera e th n tha r wide s i i parasphenoide s Corpu . D) 4 . (Fig pus, being gently bent, turn into anterior margins of lateral processes; "tick" in region of lateral pro- l latera e on m fro g passin t cres e th ; place s it n i a are l ventra e wid y fairl a s i e ther , absent s i s cesse - Scap . B) 3 . (Fig e wid y usuall s i s proces r posterio e th ; visible s sometime s i r anothe d towar s proces e b y ma s acromiali s par f o n margi r anterio ; neck w narro d an d hea e wid y comparativel a h wit a ul stretched in tenuitas acromialis (Fig. 7 B). Medial crest of humerus usually reaches the middle of the bone, with rounded margin, greatly deviated dorsally; spina medialis dorsalis may be appreciablly - su r tube h hig s ha m Iliu . B) 8 . (Fig e visibl t no y usuall s i s ventrali s mediali a spin s wherea , developed r Femu . B) 0 1 . (Fig e surfac l latera s it n o e tubercl e on h wit r o , tubercles l smal o n h wit r eithe r perio e larg n i t cres e obtus e visibl y slightl l additiona n a s i e ther s sometime ; femoris a crist y onl e th h wit . D) 2 1 . (Fig s femori a crist f o e middl e th m fro s begin h whic , specimens Osteology of Russian toads and frogs 11

Bufo - C gargarizans, Bufo - B bufo, Bufo - A : view l interna - K G- , views r oute d an l interna - N L- , A-F . Scapula . 7 . Fig verrucosissimus, D - Bufo viridis, E - Bufo raddei, F - Bufo calamita, G - Rana temporaria, H - Rana chensinensis, I - Rana arvalis, J - Rana amurensis, K - Rana asiatica, L—Rana ridibunda, M - Rana lessonae, N - Rana nigromaculata. v. Yu. RATNIK.OV 12

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- C gargarizans, Bufo - B bufo, Bufo - A : view l ventra - F E- , B-C , views l dorsa d an l ventra - D , A . (male) s Humeru . 8 . Fig Bufo verrucosissimus, D - Bufo viridis, E - Bufo raddei, F - Bufo calamita. Osteology of Russian toads and frogs 13

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chens- -B Rana temporaria, Rana - A : view l ventra - H , E , D , views l dorsa d an l ventra - G F- , A-C . (male) s Humeru . 9 . Fig ni- Rana - H lessonae, Rana - G ridibunda, Rana - F amurensis, Rana - E asiatica, Rana - D arvalis, Rana - C inensis, gromaculata. V. Yu. RATNIKOV 14

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Fig. 10. Ilium, lateral view Bufo- A . bufo, Bufo- B gargarizans, Bufo- C verrucosissimus, D—Bufo viridis, Bufo- E raddei, calamita. Bufo - F Osteology of Russian toads and frogs 15

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Fig. 11. Ilium, lateral view. A - Rana temporaria, B - Rana chensinensis, C - Rana arvalis, D - Rana asiatica, E - Rana nigromaculata Rana - H lessonae, Rana - G ridibunda, Rana - F amurensis, V. Yu. RATNIKOV 16

Fig. 12. A-B - ischium, lateral view: A - Bufo viridis, B - Rana temporaria', C-I - femur, ventral view: C - Bufo bufo, D - Bufo gargarizans, E - Bufo verrucosissimus, F - Bufo viridis, G - Bufo raddei, H - Bufo calamita, I - Rana temporaria; J-K - crus: 3 -Bufo bufo, ventral and dorsal views, Y^-Rana temporaria, dorsal, ventral views, and cross section of epiphises. s frog d an s toad n Russia f o y Osteolog

) 1811 , (PALLAS verrucosissimus Bufo The posterior part of ventral sphenethmoid area is narrow; lateral processes are long, ventral crests on them being abrupt (Fig. 1 O). External surface of maxillare without folds; posterior process of pars palatina is greatly raised and projects over the upper margin of pars facialis (Fig. 1 H). Frontoparietale gently narrowed toward the anterior end; facies cerebralis posterior more often are of ellipsoidal form with a point on the lateral side (Fig. 2 J). Ramus zygomaticus ossis squamosi is short; margins of ramus retrozygomaticus are weakly divergent or parallel, the upper margin being fairly straight (Fig. 4 E). Lateral processes and corpus parasphenoidei are of equal width; straight lateral margins of corpus, being gently bent, turn into anterior margins of lateral processes; crest in ; another d towar s proces l latera e on m fro g passin n ofte , abrupt y ver s i s processe l latera f o n regio e th the posterior process is usually wide (Fig. 3 C). Scapula usually with wide neck and greatly devel- - usu , margin d rounde a h wit , wide s i s humeru f o t cres l Media . C) 7 . (Fig s acromiali s tenuita d ope ally does not reach the middle of the bone, sometimes slightly deviated dorsally; spina medialis dorsalis et ventralis appreciablly developed (Fig. 8 C). Ilium has high tuber superior with a rough lateral surface, on which there are usually two or more small tubercles, sometimes hardly to distin- guish (Fig. 10 C). Additional obtuse crest beginning not far from distal end of crista femoris is always visible in large specimens (Fig. 12 E). . sp (viridis) Bufo Condylus occipitalis is narrower than in grey toads; torus terminalis is usually high, but abruptly limited only from the medial side, from the lateral side smoothly turning into a wall of the bone (Fig. 1 B). Elevatio prootici is slightly expressed and disposed along the diagonal of the bone; ramus lateralis prootici narrows laterally (Fig. 2 K-M). Sphenethmoideum usually with wide posterior openings of canalis olfactorii and high folds in their cavities (Fig. 1 P-R). Anterior end of maxilla pars e Nasal . I-K) 1 . (Fig s dentali s par f o d en r anterio e th n tha r furthe d forwar t projec t no s doe s faciali has a subtriangular form (Fig. 2 D-F). Frontoparietale with a slightly deviated downward lateral e ther t par l parieta d flattene f o n margi l latera e th n o ; anteriorly d narrowe y abruptl n ofte s i , margin may be a well-expressed crest (Fig. 2 K-M). Squamosum with narrow ramus retrozygomaticus (Fig. 4 F-H). Corpus parasphenoidei abruptly narrows in anterior half; its ventral surface in the region of lateral processes is flattened and has no strong bend (Fig. 3 D-F). Atlas is thiner than in grey toads, with narrower cotyles; condyle appears as strongly compressed oval (Fig. 5 B). Joint surfaces of breast vertebra bodies are very wide and strongly compressed dorsoventrally; the ventral plane of neural arch of abdominal vertebrae as a rule is longer than the dorsal one; diapophises are not widened or weakly widened at the base (Fig. 5 E, I). Sacral neurapophises are of W-like form. Humerus usually has smaller convex dorsal surface on the distal end than have representatives of grey toads. B. f o n exceptio e th , apparently , (with t pi r preacetabula a s i e ther y usuall ; thin s i i ili s ossi a Al calamita); subtriangular shape of the bone body as a rule deformed because of arch-shaped margins of pars descendens (Fig. 10 D-F). Femur with a comparatively long crista femoris (Fig. 12 F-H). Three species from the territory of the former USSR have traditionally been attributed to the green toads: Bufo viridis LAUR., B. raddei SIR., B. calamita LAUR.. Two more species have recently t e N MEZHZHERI , PlSANETZ shaartusiensis Bufo d an Z PISANET danatensis B. : described n bee - osteologi d an , absent e ar r latte o tw e th f o s spesimen s collection e th n i , Unfortunately . SZCZERBAK cal characters of only three species will be given below. Bufo viridis LAURENTI, 1768 Dorsal surface of sphenethmoideum is short; the posterior part of the ventral area is wide, the lateral processes are of moderate length; ventral crests are indistinct (Fig. 1 P). The anterior margin of maxilla pars facialis reaches the level of anterior margin of pars dentalis; on the posterior end of pars palatina there is a visible process; the external surface of the bone without folds (Fig. 11). Na- sale is wide (Fig. 2 D). Frontoparietale gradually narrows toward the anterior end; low crest is V. Yu. RATNIKOV 18 sometimes present on the lateral margin of flattened parietal part (Fig. 2 K). Pars horizontalis ossis n tha r wide h muc s i i parasphenoide s Corpu . F) 4 . (Fig t par e middl e th n i d widene y mostl s i i squamos the lateral processes; the flattened part of the bone body is wide (Fig. 3 D). Clavicula is comparatively narrow and long (Fig. 6 H). Scapula is fairly short, with very wide collum scapulae and wide s i s Humeru . D) 7 . (Fig s acromiali s tenuita n i d stretche s i n margi r anterio e whos , acromialis s par long; crista medialis is narrow, with a straight margin, slightly deviated dorsally; spinae medialis dorsalis et ventralis are absent (Fig. 8 D). Ilium with high, long, asimmetrical tuber superior (the anterior end steeper than the posterior one), bearing variable amounts of tubercles (Fig. 10 D). Femur is comparatively thin, having the shortest crista femoris among the green toads (which is, however, . F) 2 1 . (Fig . sp (bufo) ofBufo s representative e th n i n tha r longe

6 187 , STRAUCH raddei Bufo

Dorsal sphenethmoid surface is short; the posterior part of ventral area is narrow; the lateral processes long; ventral crests abrupt (Fig. 1 Q). The anterior margin of maxilla pars facialis does not - de y weakl e ar a palatin s par f o d en r posterio n o s processe ; dentalis s par f o t tha f o l leve e th h reac veloped; the external surface of the bone without folds (Fig. 1 J). Nasale is of moderate width (Fig. 2 E). Frontoparietale considerably narrows in the anterior part; on the lateral margin of parietal part in d widene t no s i i squamos s ossi s horizontali s Par . L) 2 . (Fig t cres w lo a e b y ma e ther s specimen t adul in the middle part; ramus retrozygomaticus has an arch-shaped upper margin (Fig. 4 G). The flat- t abou t a d widene y mostl e ar s processe l latera e th ; narrow s i i parasphenoide s corpu f o t par d tene one-third of their length from the distal end where they are as wide as the bone body (Fig. 3 E). r anterio e th ; scapulae m collu w narro h wit , long s i a Scapul . I) 6 . (Fig e wid d an t shor s i a Clavicul margin of pars acromialis may be stretched in tenuitas acromialis (Fig. 7 E). (Investigated material shows variations in the form of this bone: the scapulas of the toads from the Far East have comparatively wider collum scapulae than Mongolian specimens and are very similar to scapulas of B. calamita). Humerus (Fig. 8 E) is short and curved; the crista medialis is wide, with rounded margin, deviated dorsally; spinae medialis dorsalis et ventralis are well expressed. Ilium has a very high, simmetrically or almost simmetrically rising, tuber superior with large tubercle in the central part, in most cases split into two peaks or with a pit above (Fig. 10 E). Crista femoris is long, high, and thin (Fig. 12 G).

Bufo calamita LAURENTI, 1768 f o a are l ventra f o t par r posterio ; abrupt s crest l ventra e th ; long s i e surfac d sphenethmoi l Dorsa s faciali s par a maxill f o n margi r anterio e Th . R) 1 . (Fig g lon e ar s processe l latera ; width e moderat does not reach the level of the anterior margin of pars dentalis; process on posterior end of pars palatina is weakly expressed; there is a visible fold in the anterior part of the bone (Fig. 1 K). Nasale is - ex y clearl a s i e ther ; part r anterio e th n i d narrowe y strongl s i e Frontoparietal . F) 2 . (Fig w narro pressed crest along the lateral margin of the parietal part of the bone, extending on the frontal part in larger specimens (Fig. 2 M). Pars horizontalis of squamosum is widened in the middle part; ramus - Flat . H) 4 . (Fig e angl e obtus n a t a n margi r uppe e th f o d ben t abrup t somewha s ha s retrozygomaticu y approximatel s i s processe l latera e th f o h widt e th ; narrow s i i parasphenoide s corpu f o t par d tene the same almost along their extent and is appreciablly less than corpus width (Fig. 3 E). Clavicula is short, of moderate width (Fig. 6 J). Scapula is long, its neck being wider than that of B. raddei; the s mediali a Crist . F) 7 . (Fig s acromiali s tenuita n i d stretche e b n ca s acromiali s par f o n margi r anterio ossis humeri is of moderate width, with straight margin on the greater part of its length, slightly de- - prea t withou m Iliu . F) 8 . (Fig d expresse l wel e ar s ventrali t e s dorsali s mediali a spin ; dorsally d viate cetabular pit; tuber superior is high, short, narrow, sometimes with a single weakly developed . H) 2 1 . (Fig k thic d an g lon s i s femori a Crist . F) 0 1 . (Fig t par l centra n i e tubercl Osteology of Russian toads and frogs

E RANIDA Y FAMIL . IV Genus Rana LINNAEUS, 1758 - con a foss f o s border e th ; ventromedially g narrowin y graduall , narrow s i s occipitali s Condylu . C) 1 . (Fig e jugular n forame d an m the n betwee e bon f o e zon w narro a s i e ther , visible e ar a dyloide Small and large openings of long anterior semicircular canal differ greatly in size and are quite far f o s laterali s Par . G) 2 . (Fig d convexe y weakl , elongated , thin s i e Nasal . E) , D 1 . (Fig r othe h eac m fro s i m Parasphenoideu . 41-P) . (Fig s retrozygomaticu s ramu o t e angl e acut n a t a d locate s i m squamosu - pro l latera n tha r wide y slightl s i r o o t s correspond y approximatel i parasphenoide s corpu ; thin cesses; the distance between the ends of lateral processes shorter than or equal to the length of the bone (Fig. 3 G-N). Two blades of anterior pterygoid branch differ in width along their length (Fig. 4 r uppe e th ; inside d an s upward d directe s coronoideu s processu h hig h wit w lo y relativel e Gonial . B) r posterio e th ; process d coronoi f o h lengt e th g alon g extendin , crest a s a s proceed e bon e th f o n margi r fo l channe ; angle t withou n margi l latera , manner d S-shape n a n i t ben y slightl s i e bon e th f o t par Mekkeli cartilage is in the upper part of the bone under the coronoid process and widens anteriorly along its height; the lower part of the bone under coronoid process is strongly compressed with for- , thin s i h arc l neura s it ; atlas f o s cotyle o tw e th n betwee e spac o n s i e Ther . R) 4 . (Fig t cres a f o n matio e lin l media e th g alon d separate e ar s branch t lef d an t righ s it e henc , ossified t no s i t i t par r uppe e th n i (Fig. 5 C). Centra of vertebrae are small; neural arch in all vertebrae is approximately of the same n directio l cauda n i s decrease l channe l neura f o r diamete e th ; diapophises e abov s tower , thickness more gradually than in toads (Fig. 5 F, G, J-L). Join pits of urostyle are usually not separated, but sometimes can be; neural channel is high, from the anterior end of the bone it looks like an isosceles , thin y comparativel s i a Clavicul . F) 6 . (Fig t par r anterio n i d flattene s i e surfac e bon l ventra ; triangle d en l latera e th n o n expansio l smal y comparativel g havin , medially n wide t no s doe y practicall d an r anterio e th g alon s extend i cleithr s marginali a lamin l smal ; quadrangular , thin m Cleithru . K) 6 . (Fig s facie ; other h eac r cove s glenoidali s par d an s acromiali s par a Scapul . M) 6 . (Fig e bon e th f o n margi lunata is not turned outside; crista longitudinalis well developed (Fig. 7 G-N). Coracoideum is e th ; e.lateralis n tha r wide y considerabl s i s mediali s extremita t tha o s , medially d widene y abruptl medial margin of the bone smoothly rounded and in males is much more massive than in females o tw s sometime , one ; humerus f o s axi g lon h wit s coincide e trac n olecrano f o s axi g Lon . O-P) 6 . (Fig ventral crests present on the proximal half of the bone (Fig. 9). Maximum width of ischium is ob- s i s muscle b lim d hin f o t attachmen r fo a are ; ledge r acetabula f o d en r uppe e th f o d fiel e th n i d serve f o a are e th n (i t par e middl e th n i ; epiphises o t g widenin y graduall , long s i s Cru . B) 2 1 . (Fig e wid t no foramen nutritium) it has more or less rounded section, occasionally with weak kiel; on the proximal end the diameters of cross sections tibia and fibula are practically equal, and their long axes are s i n sectio a tibi e th f o r diamete d an , angle e acut n a t a e ar s axe e thes d en l dista e th n o ; parallel t almos . K) 2 1 . (Fig w furro t shor a e b y ma e ther m nutritiu n forame t a ; fibula e th f o t tha n tha s les - investi e th o t d devote e ar ) (1980 K ROCE , (1979) R GUNTHE , BOHME , (1977) E BOHM y b s Article gation of osteological features of the European species of frogs. However, they deal with only two bones: frontoparietale and ilium. The research presented here covers many more skeleton elements. s frog n gree d an , sp. (temporaria) -Rana s frog n brow : groups o tw o int d divide e ar s frog n Moder . them n betwee s distinction e demonstrat s element n skeleto e Som . sp. (esculentd) Rana - Rana (temporaria) sp. s it n i y onl , squamosi s ossi s retrozygomaticu s ramu f o n margi r oute t a t presen e b y ma t cres e Th anterior half (Fig. 4 I-M). Corpus parasphenoidei comparatively wider than in green frogs (Fig. 3 , part middle e th n i n thicke ) ledge y (b y abruptl h arc l neura l vertebra f o s plate l Horizonta . G-K) - ante d incline s i s neurapophi l Sacra . L) , K , F 5 . (Fig m platfor d elevate d develope l wel e th g formin . C) 6 . (Fig s backward t ben t no s i t i t par l centra e th n i ; inclination t withou d extende y strongl r o y riorl n o r superio r Tube . A-E) 9 . (Fig y dorsall e deviat s humeru e mal n i s c.laterali d an s mediali a Crist . A-E) 1 1 . (Fig s tubercle l smal y b d complicate y usuall d an x conve s i m iliu V. Yu. RATNIKOV

The following species of Russia (BORKIN, DAREVSKY 1987) enter the structure ofRana (temporaria) sp.: Rana temporaria L., R. chensinensis DAVID, R. arvalis NlLSSON, R. asiatica BEDRIAGA, R. amurensis BOULENGER, R. dalmatina BONAPARTE, R. macrocnemis BOULENGER. Osteological characteristics of the latter two will not be considered owing to the absence of reliable samples. Rana temporaria LINNAEUS, 1758 Flat dorsal surface of frontoparietale is limited by linea transversalis and l.medialis located over margo orbitalis; l.prooticalis and l.occipitalis are as a rule present; channel between processus prooticalis and well-expressed p.occipitalis is present; sagittal margin is straight or sometimes serrated, usually deviates laterally at the anterior end of the bone (Fig. 2 N). Ramus zygomaticus of - cau g disappearin y graduall t cres e th ; curved s i n margi r lowe s it , wide y comparativel s i m squamosu s i s laterali s par ; margin e outsid e th t a s retrozygomaticu s ramu f o t par r anterio e th n i t presen s i , dally considerally widened at the end (Fig. 4 J). Parasphenoid lateral processes are slightly narrower or equal to the width of corpus parasphenoidei, having straight or sometimes wavy margins; processus posterior is narrow (Fig. 3 G). Vertebrae usually have wide vertical and long horizontal plates of neural arch (Fig. 5 F, K). Caput scapulae accounts for 2/3 or sometimes 1/2-2/3 of the bone length; r lowe y usuall s i t cres l dorsa c Ilia . A) 9 . (Fig h widt e moderat f o , rarely , or e wid s i e scapula m collu , tubercles l severa r o e on h wit r superio r tube ; height n i t i o t l equa y occasionall r o i ili s ossi a al n tha appreciably towers above the dorsal crest and even hangs above it or, rarely, is on the same level; pars descendens is usually wide (Fig. 11 A). 5 187 , DAVID chensinensis Rana Flat dorsal surface of frontoparietale is limited by linea transversalis and 1. medialis located more often near margo orbitalis but sometimes moved medially; channel between processus prooticalis and well expressed p.occipitalis is present; sagittal margin is serrated or straight, it deviates laterally at anterior end of the bone, small sinus sagittalis is present or absent (Fig. 2 O). Ramus zygomaticus ossis squamosi is comparatively wide, its lower margin is curved; well expressed crest d en e th n o d widene y weakl s i s laterali s par ; absent s i s retrozygomaticu s ramu f o n margi r oute e th t a (Fig. 4 K). Lateral processes are somewhat narrower than corpus parasphenoidei, which has wavy, straight or less often convex lateral margins; processus posterior is usually narrow but sometimes wide (Fig. 3 H). Vertebrae have wide neural arch vertical plates as well as long sometimes moderate, horizontal plates. Caput scapulae account for more than half but less than 2/3 of the bone length; collum scapulae is of moderate width or sometimes wide (Fig. 7 H). Dorsal crest is not higher than a crist f o l leve e th t a s i t heigh s it , them t withou r o s tubercle l smal h wit r superio r tube ; ilii s ossi a al dorsalis or lower; pars descendens is wide or, rarely, of moderate width (Fig. 11 B). Rana arvalis NlLSSON, 1842 Dorsal surface of frontoparietale is convex; relief is not stable: linea medialis is simple, approaching to sagittal margin, branchy or thickened posteriorly but it may be absent; small tubercles and channels may be present on parietal part; sagittal margin is considerably serrated and deviates laterally in anterior one third; large sinus sagittalis is present; processus occipitalis is weakly expressed; p.prooticalis is considerably displaced posteriorly (Fig. 2 P). Ramus zygomaticus ossis squamosi is relatively narrow, its lower margin even; crest on outer margin of ramus retrozygomaticus is absent; pars lateralis is considerably widened at the end (Fig. 41). Lateral processes are much narrower than corpus parasphenoidei which usually has wavy or straight lateral margins (pen. 3 I). Vertebrae have narrow neural arch vertical plates as well as short, sometimes moderate, horizontal plates (Fig. 5 L). Caput scapulae accounts for about half the bone length; collum scapulae is narrow; 7 . (Fig e bon e th f o e middl e th m fro l dista y slightl t poin l cauda t mos h wit , concave s i n margi r anterio I). Crista medialis and c.lateralis are well developed, the former being better developed than the latter; distal ends of these crests are very close to each other (Fig. 9 C). (Crista medialis in all other brown frogs is well developed, c.lateralis underdeveloped, distal ends of the crests are farther from s frog d an s toad n Russia f o y Osteolog

each other (Fig. 9 A, B, D, E). Usually dorsal crest is much higher than ala ossis ilii, its highest point being over tuber superior; pars descendens is narrow; tuber superior with small tubercles sometimes smooth (Fig. 11 N). 8 189 , BEDRIAGA asiatica Rana - be r latte e th , l.medialis d an s transversali a line y b d limite s i e frontoparietal f o e surfac l dorsa t Fla ing located more medially from margo orbitalis; channel between processus occipitalis and - devi d an d serrate s i n margi l sagitta ; present e b y ma s l.prooticali d underdevelope d an s p.prooticali - occipi s processu ; present e b y ma s sagittali s sinu ; bone e th f o d thir e on r anterio e th n i y laterall s ate talis is poorly developed; p.prooticalis is slightly displaced posteriorly (Fig. 2 O). Ramus n o t presen s i t cres e acut ; bent n margi r lowe s it , wide y comparativel s i i squamos s ossi s zygomaticu outer margin of the anterior part of ramus retrozygomaticus; pars lateralis is slightly widened at the end (Fig. 4 L). Parasphenoid lateral processes and corpus parasphenoidei are of equal width, the lat- e Vertebra . J) 3 . (Fig w narro s sometime , wide s i s proces r posterio ; margins l latera t straigh s ha r te have narrow vertical and usually short horizontal plates of neural arch. Caput scapulae accounts for about half the bone length; margo anterior is twice abruptly bent; collum scapulae of moderate - anteri s decrease r o t constan s i t heigh s it ; ilii s ossi a al n tha r highe s i t cres l Dorsa . K) 7 . (Fig h widt orly; tuber superior usually slightly deviates laterally, without complicating tubercles sometimes with tubercles; pars descendens is wide (Fig. 11 D). 6 188 , BOULENGER amurensis Rana d locate , l.medialis d an s transversali a line y b d limite s i e frontoparietal f o e surfac l dorsa t Fla close to margo orbitalis; weakly expressed l.prooticalis may be present; processus occipitalis is ; quarter r anterio e th n i y laterall s deviate d an d serrate e bon e th f o n margi l sagitta ; developed y poorl s i i squamos s ossi s zygomaticu s Ramu . R) 2 . (Fig y an f i l smal s i r o t absen s i s sagittali s sinu s ramu f o t par r anterio f o n margi r oute n o t presen s i t cres ; even s i n margi r lowe s it , narrow y relativel s i s processe l latera f o h Widt . M) 4 . (Fig d en e th t a d widene s i s laterali s par ; retrozygomaticus greater or equal to the width of corpus parasphenoidei, which has straight, sometimes wavy, lateral w narro e hav e Vertebra . K) 3 . (Fig d bifurcate e b y ma d an e wid y usuall s i s proces r posterio ; margins neural arch vertical plates as well as short, sometimes moderate, horizontal plates. Caput scapulae accounts for about half the bone length; margo anterior is twice abruptly bent; collum scapulae is e th f o t heigh e th ; height l equa f o e ar i ili s ossi a al d an t cres l Dorsa . J) 7 . (Fig w narro o t e moderat former is constant to considerable extent; tuber superior is usually weakly convex, without complicating tubercles; pars descendens is short and narrow; relative length of junctura ilioischiadica is . E) 1 1 . (Fig r longe e b o t s seem e bon e th d an , frogs n brow r othe n i t tha n tha , shorter temporariesR. f o s R. bone and n skeleto f o y similarit l morphologica e clos A . Remarks - im s i t i s case y man n I . features l ecologica e clos e hav y the r Moreove . noted e b d shoul chensinensis - be y the t tha s obviou s i t i t bu , level s specie o t s frog n brow f o s remain l fossi e determin o t e possibl long to one of these two forms. For emphasis they have been determined as Rana ex gr. temporaria L. (RATN1KOV 1992, 1996b). Rana (esculenta) sp. - con a s a s retrozygomaticu s ramu f o n margi r oute e th g alon g extendin t cres a s ha m Squamosu tinuation of the upper margin of ramus zygomaticus (Fig. 4 N-P). Corpus parasphenoidei is relatively narrower than in brown frogs (Fig. 3 L-N). Horizontal plates of vertebral neural arch gradually thicken without forming the well-developed elevated platform or it is very narrow (Fig. 5 G, J). Sacral neurapophis is inclined anteriorly, its right and left branches being bend backward be- e ar i humer e mal n i s c.laterali d an s mediali a Crist . D) 6 . (Fig h arc l neura f o e centr e th n i g fusin e for . F-H) 1 1 . (Fig y laterall d flattene s i m iliu n o r superio r Tube . F-H) 9 . (Fig y dorsall d deviate t no lesso- R. , PALL. ridibunda Rana : species g followin e th s include w no s frog n gree f o p grou e Th t no s i . L esculenta R. f o n situatio c systemati e th r fa o S . . HALL R.nigromaculata d an O CAMERAN nae V. Yu. RATNIKOV

clear. Some experts consider it as a hybrid form (BANNIKOV et al. 1977; B6HME, GUNTHER 1979), others as independent species (BORKIN, DAREVSKY 1987). Osteological characters of three species will be given below, in view of the absence of reliable specimens of R. esculenta.

Rana ridibunda PALLAS, 1771

Relief on frontoparietale is well developed: as a rule, all four lines are present; processus occipitalis is well developed; processus prooticalis is displaced posteriorly; sagittal margin is fairly s turn y abruptl t par l fronta f o n margi l latera ; bone e th f o d en r anterio t a y laterall s deviate d an t straigh - squa s ossi s zygomaticu s Ramu . S) 2 . (Fig s prooticali s processu f o n margi r anterio o int s passe d an ; end e th t a s proces d spade-shape e wid a s bear h whic , retrozygomaticus s ramu n tha r longe s i i mos l latera f o h Widt . N) 4 . (Fig s horizontali s par f o t par l centra n i t presen s i s proces e obtuse-angl w lo parasphenoid processes gradually increases towards the end where it reaches the value of maximal width of corpus parasphenoidei; processus posterior is narrow (Fig. 3 L). Caput scapulae accounts for about half the bone length; margo anterior is twice abruptly bent; collum scapulae is wide (Fig. 7 L). Crista medialis of humerus is comparatively long, its margin being abruptly bent at an obtuse an- s specimen e larg n i t presen e b y ma a secundari s ventrali a crist ; narrow d an g lon s i s c.laterali ; gle d an g lon t i n o m platfor t fla e th , wide r superio r tube ; high y ver s i m iliu f o s dorsali a Crist . F) 9 . (Fig . F) 1 1 . (Fig l leve w lo t a s begin

Rana lessonae CAMERANO, 1882

Relief of frontoparietale is smoothed: very few lines are not distinguished; processus occipitalis is poorly expressed; p.prooticalis considerably displaced posteriorly; sagittal margin is serrated in t par l fronta f o n margi l latera ; bone e th f o d thir e on r anterio n i y laterall s deviate d an t par l parieta s horizontali s Par . T) 2 . (Fig s prooticali s processu f o n margi r anterio o int s passe d an y smoothl s turn ossis squamosi is short, mostly widened in the middle part; ramus zygomaticus gradually narrows towards the anterior end (Fig. 4 O). Width of lateral parasphenoid processes abruptly increases towards the ends where it exceeds the value of the maximal width of corpus parasphenoidei; processus posterior is narrow (Fig. 3 M). Scapula is long; caput scapulae accounts for less than half the t e s mediali e Crista . M) 7 . (Fig w narro e scapula m collu ; bent e twic s i r anterio o marg ; length e bon lateralis of humerus are usually comparatively short and wide, with round margins, hence the distal 9 . (Fig d expresse y weakl r o t absen s i a secundari s ventrali a crist ; wide e b o t s seem e bon e th f o d hea G). Crista dorsalis of ilium is high; tuber superior narrow, and the flat platform on it is long and be- . G) 1 1 . (Fig l leve h hig t a s gin

Rana nigromaculata HALLO WELL., 1861

Only linea transversalis and parietal piece of 1. medialis are well developed on frontoparietal surface, two another lines are not expressed; the degree of processus occipitalis development dif- fers; sagittal margin is rather straight and deviates laterally at anterior end of the bone; lateral margin of frontal part turns smoothly and passes into anterior margin of processus prooticalis (Fig. 2 U). - ra n tha r thinne y considerabl s i s zygomaticu s ramu ; short y ver s i i squamos s ossi s horizontali s Par mus retrozygomaticus and narrows near anterior end (Fig. 4 P). Width of lateral parasphenoid processes gradually increases towards the ends where it exceeds the value of the maximal width of corpus parasphenoidei; processus posterior is wide (Fig. 3 N). Caput scapulae accounts for less than ; bone e th f o e middl e th r nea t poin l cauda t mos h wit , concave s i r anterio o marg ; length e bon e th f hal s humeru f o s laterali t e s mediali e Crista . N) 7 . (Fig lessonae R. n i n tha , narrower s i e scapula m collu - ven a crist ; wide k loo t no s doe e bon e th f o d hea distal e th e henc , narrow d an g lon y comparativel e ar tralis secundaria is present (Fig. 9 H). Crista dorsalis is somewhat higher than ala ossis ilii; tuber superior is wide, and the flat platform on it short and begins at low level (Fig. 11 H). Osteology of Russian toads and frogs

IV. CONCLUSION Bone shape of toads and frogs permit their identification up to the level of species, complex, and genus. It is hardly possible to consider the above diagnostic criteria exhaustive. Further researches y morpholog e bon e th f o s feature l additiona d fin o t e possibl t i e mak y probabl l wil s material l fossi f o - undoubt s specimen f o r numbe l smal a n o t ou d carrie s observation e Som . groups n anura s variou f o edly need control and more accurate definition. In the skeletons of toads are to be found the greatest number of elements (9-11) which make it possible to define species. The most important of them are ilia, frontoparietalia, maxillaria, paras- phenoidea, and male humeri. Only 6-7 bones are used for specific identification of frogs. Most diagnostic elements are ilia, frontoparietalia, and scapulae. Other bones do not always give an unequivocal definition. Genera are distinguished very easily: almost all skeletal elements, with the exception of distal elements of limbs, have their generic signs.

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