Arvicola mosbachensis (Schmidtgen 1911) of Mosbach 2 : a basic sample for the early evolution of the genus and a reference for further biostratigraphical studies : with 6 text-figures, 2 tables and 5 plates

l~enckenber~ia~

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Advances in Vertebrate Palaeontology *)

129

6 Text-figs, 2 Tabs, 5 Pls

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Frankfurt am Main, 31.05.2000 [

Arvicola mosbachensis

(SCHMIDTGEN

1911) of Mosbach 2: a basic sample for the early

evolution of the genus and a reference for further biostratigraphical studies

With 6 Text-figures, 2 Tables and 5 Plates

LUTZ CHRISTIAN MAUL, LEONID REKOVETS, WOLF-DIETER HEINRICH, THOMAS KELLER 891 GERHARD STORCH

A b s t r a c t

Arvicola materials from Mosbaeh 2, including the types of A. mosbachensis housed at the Forschungsinstitut Senckenberg Frankfurt am Main, are described. Six specimens display incipient root development. This population is therefore one of the oldest of the genus Arvicola. This is confirmed by SDQ and tooth length values indicating a primitive evolutionary stage. The age of the population correlates with either Cromer lnterglacial III or IV.

The type material of Arvicola cantianus consists o f a few fragmentary molars only. This scarce material does not p e r m i t a clear assessment o f the most significant features in middle Pleistocene populations, rootless molars with negative enamel differentiation, and is not clearly distinguishable flora either Mimomys savini of Arvicola terrestris. We therefore propose to restrict the name

A. cantianus to the type material. All other middle Pleistocene Arvicola finds should be referred to

A. mosbachensis.

K e y w o r d s: Mammalia, Rodentia, Arvicola, Middle Pleistocene, phylogeny, taxonomy.

K u r z f a s s u n g

[Arvicola mosbachensis (SCHMIDTGEN 1911) von Mosbach 2: grundlegendes Material fª das Verst~indnis der frª Evolution der Gattung Arvicola und ein Richtmag fª weitere biostratigraphische Untersuchungen.] - - Die im Forschungsinstitut Senckenberg in Frankfurt aro Main aufbewahrten Arvicola Reste ron Mosbach 2, einschlieBlich des Typusmaterials von A. mosbachensis, werden beschrieben. Die an seehs Exemplaren zu beobachtende beginnende Wurzelbildung belegt, da6 es sich hierbei um eine der ~iltesten Arvicola Population handelt. Die SDQ-Werte sowie die Zahnl~ingen verweisen ebenfalls auf ein primitives Evolutionsniveau. Das Alter der Population kann mit dem Cromer lnterglazial III oder IV korreliert werden.

Das Typusmaterial ron Arvicola cantianus besteht nur aus wenigen fragmentarischen Molaren. Hierbei kann die Ausbildung der f'¨ die taxonomische Zuordnung der mittelpleistozfinen Arvicola Funde wichtigen Merkmale, Wurzellosigkeit der Molaren und negative Schmelzdifferenzierung, nicht eindeutig festgestellt werden. Das Material ist somit weder ron Mimomys savini noch von Arvicola

terrestris eindeutig abgrenzbar. Daher wird vorgeschlagen, die Verwendung des Namens A. cantianus auf das Typus Material zu beschr~inken. Alle anderen mittelpleistozfinen Arvicola Funde sollten zu

A. mosbachensis gestellt werden.

*) Special issue o f Senckenbergiana lethaea, edited by GERHARD STORCH & KARSTEN WEDDIGE

Addresses of the authors: Dr. LUTZ MAUL, Forschungsstation f'ª Quart/irpaliiontologie des Forschungsinstituts Senckenberg, Steubenstral3e 19a; D-99423 Weimar. Prof. Dr. LEONIO REKOVt~IS, Zoologisches lnstitut der Akademie der Wissenschaften der Ukraine, ul. Chrnelnitzki 15: 252650 Kiev 30, Ukraine. Dr. WOLV-DIETER HEINRICH, Geologisch-Palfiontologisches Institut und Museum, Museum fª Naturkunde der Humboldt-Universit/it zu Berlin, lnvalidenstraBe 43; D-10115 Berlin.- Dipl.-Geol. THOMAS KELLER, Landesamt fª Denkmalpflege Hessen, Schlof3 Biebrich/Ostflª D-65302 Wiesbaden. Dr. GERUARO STORCH, Forschungsinstitut Senckenberg, Senckenberganlage 25; D-60325 Frankfurt am Main.

130 MAUL, REKOVETS, HEINRICH, KELLER ~91 STORCH: Arvicola mosbachensis (SCHMIDTGEN 1911) of Mosbach 2: ...

C o n t e n t s

Introduction ... 130

The Mosbach Sands ... 130

Small mammal fauna composition and environment ... 130

Arvicola mosbachensis from Mosbach 2 ... 131

Chronological implications and discussion ... 132

Taxonomic comments on early Middle PleistoceneArvicola remains ... 133

Acknowledgements ... 136

References ... 136

I n t r o d u c t i o n

Finds of the Mimomys savini - Arvicola lineage are used ex-

tensively in the biostratigraphic subdivision of the Pleistoce- ne in Eurasia (e. g. J93 1969; KOENIGSWALD 1973; FEJFAR & HEINRICH 1980; ZAZH~GIN 1980; KOLFSCHOTEN 1990; KOENIGSWALD & KOLFSCHOIEN 1996). One of the rea- sons is that these voles are widespread and often numerous. The other reason is that the main characters that distinguish evolutionary stages - the presence or lack o f roots, and relati- ve enamel thickness of the posterior to the anterior cutting edges of the molars - can be clearly defined.

The ancestor of Arvicola LAC• 1799, Mimomys savi- ni HINTON 1910 (e. g. CHALINE 1972; AGADZHANYAN 1983;

KOEN1GSWALD & TOBIEN 1987; KOENIGSWALD & KOLFSCHO- TEN 1996), already possesses hypsodont but still rooted mo- lars. The increasing hypsodonty eventually leads to the loss of roots. Another tendency relates to changes in the relative thickness of the enamel cutting edges. Contrary to the situati- on in Mimomys savini, and in ancient Arvicola, in most of the

recent Eurasian populations of Arvicola the enamel walls are

thinner in the posterior edges of the lower molars and in the anterior edges of the upper ones. In addition, the occlusal surface patterns of the M/1 change somewhat with time, and the length of this tooth also increases.

Al1 features are, however, variable within populations. On the basis o f their different developmental degree in recent populations within the whole distribution range

(ROTTGER

1987) one can therefore also expect regional differences in the fossil record. The evolution of these features can be safely assessed only by statistical evaluation and further biostrati- graphic studies require well-defined samples.

Consequently, the present situation where the poorly pre- served type material of Arvieola cantianus (HINTON 1910)

from Ingress Vale, Kent, England, is considered as the refe- rence for the ancestral stage of the genus is not satisfactory. On the other hand, the well known German locality of Mos- bach 2 has been providing an increasingly rich material of

Arvicola, re-examination of which now enables us to suggest

a much better reference for this early stage o f the evolution of water roles o f the genus Arvicola. In this article a rather large Arvicola-sample from Mosbach 2 is documented and its

biostratigraphic and taxonomic implications discussed.

T h e M o s b a c h S a n d s

The so-called Mosbach Sands are fluviatile sediments of the rivers Main and Rhine, and are excavated industrially in the eastern part of Wiesbaden. On lithological and palaeontologi-

cal grounds they can be subdivided into two parts of different stratigraphic age, Mosbach 1 and 2:

- Mosbach 1 ("Grobes Mosbach")

This section is dominated by coarse clastic sediments. In su- perimposed fine-granular sediments a palaeomagnetic rever- sal was recorded and interpreted as the Jaramillo Event (see BR• 1978 and KOENIGSWALD & TOBIEN 1987). Thus, the fauna o f Mosbach 1 is older than the base of this reversal.

Arvicola-remains have not been recorded in that section.

- Mosbach 2 ("Graues Mosbach")

Sediments o f the "Graues Mosbach" of 13 m thickness discordantly overlay the sediments o f Mosbach 1. Within this sediment body several discordances suggest the existence o f different fluviatile sequences. BR• (1978) established a subdivision of the "Graues Mosbach" into Mosbach 2 and 3 (see also KOENIGSWALD & TOBIEN 1987). However, according to sedimentological and faunal investigations this subdivision is less likely.

The majority of small mammal remains including all Arvico- la finds originate from Mosbach 2. The more recently collec-

ted remains from the area o f the "Abbaufeld Ostfelder" (BAHLO & MALEC 1969, AYDRES 1971, and specimens collec- ted by TH. KELLER) originate from medium grained to coarse sands o f brown ochre to grey colour with frequently interstra- tificated fine gravels, but occasionally occurred also in greyish green medium to fine grained sands. Arvicola finds

are known from all major parts of the Mosbach 2 profile.

S m a l l m a m m a l f a u n a c o m p o s i t i o n a n d e n v i r o n m e n t We considered the complete materials housed at the For- schungsinstitut Senckenberg, Frankfurt am Main, and at the

Naturhistorisches Museum/Landessammlungen fª Natur-

kunde, Mainz, including previously published specimens

(SCHMIDTGEN

1911; HELLER 1933; 1969, BAHLO & MALEC

1969; KOEN~GSWaLD & TOMEN 1987) as well as newly collec- ted stratified specimens (TH. KELLER, Landesamt ffir Denk- malpflege Hessen, Wiesbaden). The numbers of specimens in tab. 1 are based on all available dental and postcranial ele- ments of Desmana, soricids, Sciurus, and Lepus; on humeri

o f Talpa; on P/4 of Trogontherium and Castor; and on M/1 of

arvicolids. General overviews o f the Mosbach mammalian faunas are provided by KAHLKE (1961), BRª (1978) and KOEMGSWALO & TOB~EN (1987).

The striking predominance o f Arvicola and the occur-

MAUL, REKOVETS, HEINRICH,

KELLER & STORCH: Arvicola mosbachensis

(SCHMIDTGEN

1911) of Mosbach 2: ... 131

gest varied freshwater bodies such as rivers, abandoned river courses, and ponds with dense vegetation cover along the waters edge, and at least some patchy riparian forest. Among shrews, Drepanosorex and neomyines ate also assumed to

have been semiaquatic. On the other han& the absence of typical forest species such as glirids and Apodemus, which

would predominate in forested environments, suggests rather open conditions at least in the area of accumulation of the micromammal remains. Thus, we conclude a vast well-wate- red plain as the local Mosbach paleoenvironment.

The composition o f the micromammal fauna as represen- ted in our samples generally resembles temperate present-day faunas of the same latitudes. The occurrence of Lemmus

seems to contradict this assessment but the genus is known to be present in various kinds o f early and middle Pleistocene ecosystems. Thus, temperate conditions for the Mosbach en- vironment are most likely, although any more detailed clima- tic assessment is impossible due to our still poor understan- ding of relevant faunal characters during these periods.

Arvicola mosbachensis f r o m M o s b a c h 2

The initial smail sample of water voles ffom Mosbach was described by SCHMIDTGEN (1911) as Microtus mosbachensis.

Later, both the type material and additional new material were referred to several species of Arvicola, including Ar- vicola mosbachensis (HECLER 1933, 1969). Even today, furt-

her remains ate being collected. A large sample of material excavated from this site is now preserved at the Forschungs- institut Senckenberg Frankfurt am Main. It consists of 102 sufficiently well preserved M / l , 23 M3/, and more than 150 other molars or fragments thereof. Among this material are the type specimens of Arvicola mosbachensis: one left man-

Tab. 1. Fossil site Mosbach 2, numbers of specimens of small mammal remains (basing on all available elemts in Desmana,

soricids, Sciurus, and Lepus, on humeri in Talpa; on P/4 in Trogontherium and Castor, and on M/1 in arvicolidis). Microtus arvalinus = Microtus nivaloides, and Microtus ratticepoides -

M. nivalinus according to REKOVETS & NADACHOWSKI (1995).

M/1 o ~ e r d e m e ~ s Talpa ex gr. fossilis 67 Talpa minor 4 Desmana moschata 13 Sorcidae indet. 3 Sorex sp. 1 Drepanosorex savini 1 Neomyini indet. 2 Sciurus Castor fiber Trogonthen'um cuvieri Lemmus sp. 4 Clethrionomys acrorhiza 9 Pliomys episcopalis 2 Arvicola mosbachensis 456 Microtus nivaloides 20 Microtus hintoni 6 Microtus nivatinus 1 Lepus sp. 1 52 57 10

1

11(45,6%) 11{45,8%) 2(8,3%) 0(0%) 15{62,5%)9(37,8%)

wlth

25

(37,3 %) 22

(32,8 %) 29 129,8 %1 14 (20

/

Text-fig. 1. Developmental degrees of S14 and Sb3 (forming an angle less than 90 o, approximately 90 o, and larger than 90 o) of M/l, fossil specimens from Mosbach 2 and recent specimens of Arvicola terrestris.

dible with M/1 and M/2 (SMF 74/4835, holotype: pl. 1 fig. 1) and 18 isolated molars (SMF 74/4836-53, paratypes: pi. 1 figs 2, 3, 5, 6). The catalogue numbers of the other M/I and M 3 / w h i c h ate included in the present analyses, are SMF 99/ 1543-662. Many of the speeimens were collected under stra- tigraphical control from the Mosbach profile.

The cheek teeth are hypsodont. Synclines are normally filled with crown cement which may be lacking in corroded specimens. Occasionally parts of the dentine are eroded. With the exception o f two mandibular fragments, the molars are isolated. Most specimens are pictured in plates 1-5.

As is typical for Arvicola, the majority of molars have no

trace of roots. Two M / l , however, (i. e. 2% of all M / l ) and four M 3 / ( 1 0 % of all M3/) display different degrees of incipi- ent roots. This is never seen in modern Arvicola teeth and

contradicts the rootless condition commonly assumed for that

sample (SCHMIDTGEN

1911; HELLER 1933, 1969). Similar sta- ges of root development have been recently documented in

Arvicola teeth of the localities Gura Dobrogei 4, Casian

Cave, Romania (RADULESCU & SAMSON 1993), and Isernia, Italy (KOENIGSWALD & KOLFSCHOTEN 1996).

The mesial anteroconid complex (ACC) o f the M/1 has synclines S14 and Sb3 developed to different degrees (text- fig. 1); in some specimens an additional anticline Ab4 is more or less conspicuous. The Mimomys-fold (= Mimomys-

Kante) occurs in 27% of all specimens with preserved ACC. Compared with recent Arvicola terrestris (LINNAEUS 1758),

the frequent occurrence of the Mimomys-Kante in the materi-

al from Mosbach, as well as the more shallow S14 and Sb3, indicate a rather primitive state of the ACC.

The occlusal surface of the M3/ is typical for Arvicola:

three lingual and three buccal anticlines are divided by two synclines on each side. Additional synclines are developed on both sides to various extent. Usually, a confluence broader than in recent Arvicola terrestris is to be seen between the

triangles T3 and T4.

Al1 the molars of Mosbach 2 are smaller than in modern

Arvicola terrestris. The measurements of the M/1 are docu-

mented in tab. 2. The mean length of the M3/ is 2.18 mm (ruin = 2.04 mm, max = 2.3 l mm, n = 7, sd = 0.086).

As already mentioned, Mimomys savini and the ear[y

forros of Arvicola have thicker posterior edges than anterior

132 MAUL, REKOVETS, HEINRICH, KELLER 8r STORCH: Arvicola mosbachensis (SCHMIDTGEN 1911) of Mosbach 2: ... >

g,

_o = - 2 fi x ._= E .=_ E E e - ~ ,~- ~ ~ ~, ~ ~ Tab. 2. M/1 measure- i-,,1 ~ f'-I r ~ r r

& ~ ~ ~ ~ ~ ~" ments of several

e ~ ~ re5 ~ t ~ e N t i 3

m ~ ~ :~ o, ~ ~- o, middle and late Plei-

~ ~ ~ ~ ~ ~ ~ stocenepopulationsof

~ ~ ~ ~ ~ ~ ~ Arvicola: length, SDQ

~ eq ~ ~ ~ ~ ~ (the relative thickness mm ~ ~ ~ mm ,~ ,,~ e- of the posterior cut- o, ~ o, - ,~ m ~ ~ ting edges of allanti- ,,:, ~ ,~ m ,-- ~ ,:, clines expressed as a

. . . ~ ~ percentage of the cor-

responding anterior cutting edges), SZQV ~" ~, ~ ~ ~ ~, mm (the relative thickness ~ ~ ~ ~ & ~ ~- of the anterior cutting m~ ~ ~ ~ ~ ~. ~ edges of all anticlines '::' ~ ~ ~ ~ ~ ~ ' : : ' expressed as a per- ~ ~ _ ~ ~ ,~. ~. centage of the occlu- ~ m~ ~m ~"" ~~ ~'~" ~~ eq ~ sal length of the tooth), SZQH (the re- ~ ~ ~ ~ ~ ~ m~ lative thickness of the posterior cutting ed- 9 ~- ~ ,~- ~ ,~ ~- ~o ges of all anticlines expressed a s a per- t-. ~ t-. ~ o~ o, ~ ~ centage of the occlu- sal length of the eq eq eq ~ ~ -- ~ -- tooth): d d ~ d & d d d ~ ~ M M M M M M , ~ . ~ . ~ . ~ . ~ 9 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

~ ~ ~ ~ ~ ~ ~ ~ ~

.-

The primitive differentiation has been defined as 'negative' and evolves into a 'positive' one (MARTIN 1987). The percent relation o f the posterior to the anterior cutting edges in M/1 is expressed by the parameter SDQ (Schmelzband-Differentie- rungs-Quotient) which was devised by HEINRICH (1978; for details see also HEINRICH 1982). Another index (SZQ, see HEINmCH 1982) concerns the enamel thickness relative to the length o f the tooth. In contrast to the modern Arvicola terre-

stris, the enamel differentiation is negative in all lower cheek

teeth and positive in all upper ones (for M/1 see tab. 2).

C h r o n o l o g i c a l i m p l i c a t i o n s a n d d i s c u s s i o n

The Arvicola population of M o s b a c h 2 has been compared

with Arvicola remains from other G e r m a n localities. Some o f the features described above provide a suggestion of the rela- tive order o f the populations.

All the Arvicola populations m e n t i o n e d in tab. 2 are com- pletely rootless with the exception o f M o s b a c h 2. According to this character, Mosbach 2 is the oldest Arvicola fauna and therefore appears even older than M i e s e n h e i m 1 where the absence o f roots was established in a sample o f more than 150 specimens (KOLFSCHOTEN, in litt.).

A general and rather consistent decrease o f the SDQ has b e e n d o c u m e n t e d for numerous middle and late Pleistocene water vole populations in Europe (HEINRICH 1982, 1987; KOLFSCHOTEN 1990; REKOVETS 1994). I f we consider the per- centages o f specimens belonging in six classes o f SDQ, Voigtstedt, M i e s e n h e i m 1, M o s b a c h 2, Bilzingsleben 2, Pe- tersbuch 1, Stuttgart/Untertª Burgtonna 2, and Euer- wanger Bª H, a chronological succession may be observed (text-fig. 2). A similar succession can be seen when average values are considered for each population but with an inversi- on between Voigtstedt and M i e s e n h e i m 1 (text-fig. 3).

According to the M/1 length, the localities mentioned above can be ordered in the same way as according to the SDQ index, with the same exception: as for the root charac- ter, M o s b a c h 2 appears older than M i e s e n h e i m 1 (text-fig. 4). This compares well with the S Z Q H ratios (tab. 2). The ACC m o r p h o l o g y shows less incised synclines in comparison to recent Arvicola terrestris but no clear comparison with other localities is possible so far.

In summary, according to the presence o f incipient roots in some specimens, as well as M / I length, SDQ, and SZQH, M o s b a c h 2 is older than Bilzingsleben, Petersbuch, Stuttgart/ Untertª Burgtonna 2, and Euerwanger Bª H. This is also in agreement with the species composition o f these fau- nas: in M o s b a c h 2 there are taxa (Talpa minor, Trogontheri-

um, Pliomys) which disappear during the later part o f the

middle Pleistocene but which still occur in the older faunas o f this period (text-fig. 5). Beside M o s b a c h 2, Miesenheim 1 is the only other site with the co-occurrence of these taxa. Three characters (roots, M/1-1ength, SZQH) favour ah older age for M o s b a c h 2 than Miesenheim. One, the SDQ places M o s b a c h 2 as younger.

Still it is not clear which character has the greatest biostratigraphic value. The transition to rootless molars is an irreversible process, and therefore this character seems to provide the strongest argument. Without doubt, the Mimomys

savini population from Voigtstedt, with a domination o f

MAUL, REKOVETS, HEINRICH, KELLER ~r STORCH: Arvicola mosbachensis (SCHMIDTGEN 1911) of Mosbach 2: ... 133 0% Euerwanger Bª H Burgtonna 2 Stuttgart/Untertª Petersbuch 1 Bilzingsleben 2 Mosbach 2 Miesenheim 1 Voigtstedt 10% 20% 30% 40% 50% 60% 70% 80% 90% I t I I I I t I I ::::::::::::::::::::::::::::::::::::::::::::

•::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::l

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~ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \

~\\\~\\\\\\\\\\N\\\NNN

~ \ N \ \ \ \ \ \ \ \ N \ \ \ \ \ \ \ \ N 1

: _ ~ N \ \ \ \ \ \ \ N \ \ \ N \ N N \ \ ' 9 i 100%

S D Q size classes li 185-165 r'1165-145 r'1145-125 I-I125-105 O 105-85 85-65

Text-fig. 2. SDQ size classes of M/I of several fossil populations of Arvicola. Vertical bars indicate the maximum possible age range.

the only locality where incipient root creation could be obser- ved, should be the next youngest fauna and older than Mie- senheim 1. When comparing the two latter populations, there is no reason to interpret the differences in this feature as evidence for different age structures o f the populations since more than 150 molars are known from both localities. The older age o f Mosbach 2 is in agreement with the smaller size of M/1 and the larger values of SZQH. The M/1 from Voigt- stedt ate a little larger in comparison to those from Mosbach, but this concerns the rooted specimens only. Rootless M/1 from this site ate of similar size (x = 3.27 mm, ruin = 3.00 mm, max = 3.65 mm, n = 21).

On the other hand, ah older age for Miesenheim 1 could be inferred from the higher SDQ values in comparison to Mosbach. ttowever, geographical clines have been observed in recent populations within Europe (ROTTGER 1987). Even in various places in Germany, the mean values already differ considerably (between 78 and 8 5 - FRAHNERr 1991). This is the same difference of SDQ values as that between Miesen- heim and Mosbach (140 to 133). Another argument is that despite Voigtstedt being clearly older than Miesenheim, it has smaller SDQ values. For biochronological correlations, more data are necessary to estimate the geographic variability of these features.

KOENIGSWALD & KOLFSCHOTEN (1996) place the first ap- pearance dates of Arvicola in Europe in the Cromer Intergla- cial III. By several arguments they refer Miesenheim to Inter- glacial IV. Mosbach 2 should therefore be placed in one of these two interglaeials.

Taxonomic c o m m e n t s on early Middle Pleistocene

Arvicola remains

The current taxonomic expression o f the three main levels of the successive evolution are: Mimomys savini with roots and negative enamel differentiation, Arvicola cantianus without

roots and negative enamel differentiation, and Arvicola terre-

stris without roots and with positive enamel differentiation

(KOENIGSWALD 1973; HE1NRICH 1982; KOENIGSWALD & KOLF- SCHOTEN 1996).

Several middle Pleistocene Arvicola species with negative enamel differentiation have been previously described: Ar-

vicola mosbachensis (SCHMIDTGEN 1911), A. greeni HINTON 1926, A. praeceptor HINTON 1926, A. bactonensis H[NTON 1926, A. weinheimensis HELLER 1952, and A. moenana HEL- LER 1969. However, they are now usually considered as parti- ally different morphotypes of a single species, one which, for reas£ o f priority, has been named Arvicola cantianus (HIN- TON 1910) with the type locality Ingress Vale, Kent.

However, there is a problem with the type specimens of

Arvicola eantianus since these finds are not clearly referable

to one of the three successive species mentioned. Only two fragmentary M/1 one M I / , and one M 3 / a r e known from this site (HINTOY 1926). Because there are also rootless speci- mens in the population of Mimornys savini from Pfezletice, the single molars from Ingress Vale cannot be referred wit- hout doubt either to Arvicola or to Mimomys. Moreover, ac- cording to the SDQ values (120 measured on 4 anticlines of the type specimen, and 115 measured on 3 anticlines of another M / l ) the two M/1 can be referred to middle as well as to late Pleistocene forms of both types of enamel differen- tiation. Because the M/I are incomplete, and their lengths can be only estimated to around 3.5 mm, this measurement also refers the finds to either the middle or to the late Pleisto- cene species. Thus, even in crucial features, the character states are not clearly recognisable in these specimens, and a clear distinction is impossible. This taxon is therefore not suitable a s a reference (a nomen dubium).

Moreover, with increasing knowledge about middle Plei- stocene Arvicola populations, a more detailed subdivision is necessary. The Ingress Vale specimens do not provide any possibility of comparison with other populations, neither for detailed relative chronology nor for geographical clines. The-

1 3 4 MAUL, REKOVETS, HEINRICH, KELLER 891 STORCH: Arvicola moshachensis ( S C H M I D T G E N 1911) o f M o s b a c h 2: ...

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O _ _ t O _ _ t O 0 _ _ 0 1 0 _ _ - , q 0 Text-fig. 3. SDQ (mean va- lues, variation and confidence interval) and SDQ size clas- ses o f M/1 of several fossil populations o f Arvicola and recent popula- tions o f Arvi- cola terrestris. Vertical bars indicate the maximum pos- sible age range.

MAUL, REKOVITS, [-IEiNRK'H, KELLER & STORCH: A r v i c o t a m o s b a c h e n s i s (SCHrvlIDT(;EN l C) l I ) Of Mosbach 2: ... 135 Text-fig.

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M/1 length (mean values, variation) o f several fossil populations o f A r v i c o l a and re- cent specimens o f A r v i c o l a terres- tris. Vertical bars indicate the max- imum possible age range.

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136 M A U L , REKOVETS, H E I N R I C H , K E L L E R & STORCH: Arvicola mosbachensis ( S C H M I D T G E N 1 9 1 1 ) o f M o s b a c h 2 : ...

strati~raphic

unit 6 ~~ 0 stage Locality

Weichselian Eemian Saalian Holstein Elsterian Cromer IV 5e Euerwanger B0hl Burgtonna 2

Stuttgart Bad Cannstadt

7 or 9 Petersbuch 1 9 or 11 Bilzingsleben 2 11 or 13 Cromer HI 13 or 15 Cromer II 15 of 17 Miesenheim 1 Mosbach 2 Voigtstedt : : : : : : : : : : : : " ~ : J " ~ : 2 : 2 : i : : : : : : : : : : : : i ~ ~ ' "~ i i ~~ i " ' ! i i ~! i i i ! i i ! i i ~! ! i ! ! i i i g i ~ ! ! i ~! i i i

i !i ii !i ii ii

!

i i i i i i i i i i i i

Text-fig. 5. Stratigraphic range of some Pleistocene small mammal taxa (after KOLFSCHOTEN 1990, and KOENIGSWALD & KOLFSCHOTEN 1996).

8 mm

Text-fig. 6. Arvicola cantianus" (HJNTON 1910), holotype. Brit. Mus. natur. Hist. [BMNH] London, catalogue number M 48392.

se things are o f importance in answering the question o f whe- ther the transition M. savini - Arvicola occurred everywhere in Europe at about the same time (it did probably not). In addition, the influence o f possible migrations must be consi- dered. The types o f A. cantianus cannot be used for these kinds o f investigations. B e c a u s e i t i s i m p o s s i b l e t o a s s e s s c l e a r l y d i a g n o s t i c s t a g e s i n t h e s e f e a - t u r e s , w e p r o p o s e t o r e s t r i c t t h e n a m e A r - v i c o l a c a n t i a n u s ( H 1 N T O N 1 9 1 0 ) t o t h e m a t e r i a l o f I n g r e s s V a l e . F o r a l l o t h e r m i d d l e P l e i s t o c e n e f i n d s w i t h n e g a t i v e e n a m e l d i f f e r e n t i a t i o n t h e n a m e A r v i c o l a m o s b a c h e n s i s ( S C H M | D T G E N 1 9 1 1 ) i s a v a i l a b l e a n d s h o u l d b e a p p l i e d . F o r t h e M o s - bach population these features can be assessed with sufficient confidence because the sample is large, and has the added advantage o Ÿ rich accompanying m a m m a l i a n fauna.

We do not support the use o f subspecific names as propo- sed by KOLFSCHOTEN (1990). In addition to all the problems with chrono-subspecies discussed elsewhere (REMANE 1985), there is no practical advantage in the relegation o f former species to subspecific rank. If regional differences o f data in penecontemporaneous fossil sites are referred to different ra- ces, it will be impossible then to subordinate geographical defined subspecies under biostratigraphically defined ones.

A c k n o w l e d g e m e n t s

For critical discussions and advises we are indebted to Dr. V. EISENMANN, Dr. S. SEN (both Paris), Dr. D. SCHREVE (Lon- don), and Dr. A. TURNEa (Liverpool). Special thanks to Dr. A. CURRAYT (London) who provided useful comments and a de- tailed drawing o f the type specimen o f A r v i c o l a cantianus.

References

AGADZHANYAN, A. K. (1983): Eine altertª Arvicola (Rodentia, Mammalia) aus dem Mittelpleistoz~in der Russischen Ebene. - Schriftenr. geot. Wiss, 19/20: 9-29, 7 text-figs, 5 tabs; Berlin. AYDRES, W. (1971): Sedimentologische und morphoskopische

Untersuchungen eines Fundprofiles aus den pleistozfinen Mosbacher Sanden bei Wiesbaden-Bieberich. Mainzer naturwiss. Arch., 10:101-112, 8 text-figs; Mainz.

BAHLO, E. & MALEC, E (1969): Insectivoren (Mammalia) aus den oberen Mosbacher Sanden (Mittelpleistoz~in) bei Wiesbaden- Biebrich/Hessen. - Mainzer naturwiss. Arch., 8: 56-76, 5 text- figs, 6 tabs, 2 pls; Mainz.

BR• H. (1978): Zur Untergliederung der Mosbacher

Terrassenabfolge und zum klimatischen Stellenwert der

Mosbacher Tierwelt im Rahmen des Cromer-Komplexes. - Mainzer naturwiss. Arch., 16: 143-I90, 12 text-figs, 3 tabs; Mainz.

C H A L I N E , J. (1972): Les rongeurs du Pleistoc6ne moyen et sup› de France. - Cah. Pal› CNRS: 410 p., 72 text-figs, 3 tabs, 17 pls; Paris.

FEJFAR, O. & HE1NRICH, W.-D. (1980): Zur biostratigraphischen Abgrenzung und Gliederung des kontinentalen Quart~irs in Europa anhand von Arvicoliden (Mammalia, Rodentia). - l~as. Mineral. Geol., 25: I85-I89, I text-fig; Praha.

FEJFAR, O. & HEINRICH, W.-D. (1989): Muroid Rodent Biochro- nology of the Neogene and Quaternary in Europe. - In: E. H. LINDSAY, V. FAHLBUSCH & E MEIN [Eds], European Neogene

MAUL, REKOVETS, HEINRICH, KELLER & STORCH: Arvicola mosbachensis (SCHMIDTGEN 1911) of Mosbach 2: ... 137

Mammal Chronology: 91-116, 5 text-figs; New York, London (Plenum Press).

FRAHNERT, S. (1991): Zur Variabilit~it der Schmelzbandbreiten rezenter Scherm/iuse, Arvicola terrestris (Rodentia, Mammalia), ira zentralen Mitteleuropa. - S~iugetierkundl. Inform., 3: 235- 247, 13 text-figs, 5 tabs; Jena.

HEINmCH, W.-D. (1978): Zur biometrischen Erfassung eines Evolutionstrends bei Arvicola (Rodentia, Mammalia) aus dem Pleistoz/in Thª S~iugetierkundl. Inform., 2: 3-21, 5 text-figs; Berlin.

HEINRICH, W.-D. (1982): Zur Evolution und Biostratigraphie von

Arvicola (Rodentia, Mammalia) im Pleistozfin Europas. - Z. geol. Wiss., 10: 683-735, 26 text-figs, 3 tabs; Berlin. HEINRICH, W.-D. (1987): Neue Ergebnisse zur Evolution und

Biostratigraphie ron Arvicola (Rodentia, Mammalia) im QuartS_r Europas. - Z. geol. Wiss., 15: 389-406, 9 text-figs; Berlin. HELLER, E (1933): Die Wª der Mosbacher Sande. -Notizbl.

Ver. Erdkde. u. hess. geol. L.-Anst., 1931/1932: 108-116, 1 pi.; Darmstadt.

HELLER, E (1969): Eine Kleinsfiugerfauna aus den Mittleren Mosbacher Sanden bei Biebrich-Wiesbaden. - Mainzer naturwiss, Arch., 8: 25-55, 3 text-figs, 2 pls; Mainz.

HINTON, M. A. C. (1910): A preliminary account o f the British fossil voles and lemmings; with some remarks on the Pleistocene climate and geography. Proc. Geologists' Assoc., 21: 489-507,

1 tab.; London.

HINTON, M. A. C. (1926): Monograph o f the voles and lemmings (Microtinae) living and extinct. - 488 p., 110 text-figs, 56 tabs,

15 pis; London (Brit. Mus. natur. Hist.).

J93 D. (1969): Stratigraphische Auswertung der europ/iischen mittelpleistoz/inen Wirbeltierfaunen. Teil I. - Ber. dt. Ges. geol. Wiss., (A) 14: 367-438, 8 text-figs; Berlin.

KAHLKE, H.-D. (1961): Revision der S/iugetierfaunen der klassischen deutschen Pleistoz~in-Fundstellen von Sª Mosbach und Taubach. -Geologie, 10: 493-532, 7 pls; Berlin.

KOENIGSWALD, W. VON (1973): Ver/inderungen in der Klein- sgugerfauna ron Mitteleuropa zwischen Cromer und Eem (Pleistozhn).- Eiszeitalter u. Gegenwart, 23/24: 159-167, 2 text- figs; Ohringen.

KOENIGSWALD, W. VON & KOLFSCHOTEN, 12 VAN (1996): The

Mimomys-drvicola boundary and the enamel thickness quotient (SDQ) o f Arvico]a as stratigraphic markers in the Middle Pleismcene. - In: Ch. TURNER [Ed.], The Early Middle Pleistocene in Europe: 211-226, 7 text-figs; Rotterdam (A. A. Balkema).

KOENIGSWALD, W. VON & TOBIEN H. (1987): Bemerkungen zur Altersstellung der pleistoz/inen Mosbach-Sande. - Geol. Jb. Hessen, 115: 227-237, 2 text-figs, 1 tab.; Wiesbaden.

KOLFSCHOTEN, T. VAN (1990): The evolution of the mammal fauna in The Netherlands and the middle Rhine Area (Western Germany) during the late Middle Pleistocene. - Meded_ Rijks Geol. Dienst., 43:1 69, 27 text-figs, 11 tabs; Haarlem.

MARTIt~, R. A. (1987): Notes on the classifications and evolution of some North American fossil Microtus (Mammalia, Rodentia). - J. Vertebrate Paleont., 7: 270-283, 7 text-figs, 2 tabs; Lawrence/ Kan.

RADULESCU, C. & SAMSON, R-M. (1993): Dental morphology o f the

Mimomvs/Arvicola transition forms. - Theoret. and applied Karstotogy, 6: 199-206, 1 text-fig., 1 tab.; Bucuresti.

REKOVETS, L. I. (1994): Melkie mlekopitayushchie antropogena yuga vostochnoj Evropy. [Small mammals of the Anthropogene of Eastern Europe.] 370 p., 73 text-figs, 36 tabs; Kiev (Naukova dumka). [In Russian.]

REKOVETS, L. 1. & NADACHOWSKI, A. (1995): Pleistocene voles (Arvicolidae) of the Ukraine. - Paleontologia i Evoluci£ 28/29: 145-245, 76 text-figs, 47 tabs; Sabadell.

REMANE, J. (1985): Der Artbegriff in Zoologie, Phylogenetik und Biostratigraphie. PalS.ont. Z., 59: 171-182; Stuttgart.

ROTT~ZR, U. (1987): Schmelzbandbreiten an Molaren von Scherm/iusen (Arvicola LAC• 1799). - Bonner zool. Beitr., 38: 95-105, 7 text-figs, 2 tabs; Bonn.

SCHMmV~EN, O. (1911): • Reste von Wª aus dem

Mosbacher Sand. - Notizbl. Ver. Erdkde. u. GroBherzogl. geol. L.-Anst., 4. Folge, 32: 185-193, 3 text-figs, I tab.; Darmstadt. SHACKLE'rON, N. J. (1995): New data on the evolution of Pliocene

Climatic Variability. - In: E.S. VRBA, G.H. DENTO, T.C. PARTR1DGE & L. H. BURCKLE [Eds], Paleoclimate and Evolution, with Emphasis on Human Origins: 242-248, 3 text-figs, 3 tabs; New Haven, London (Yale Press).

TIEDEMANN, R., SARNTHEIN, M. & SHACKLETON, N. J, (1994): Astronomic timescale for the Pliocene Atlantic 8 ~sO and dust flux records of Ocean Drilling Program site 659. - Paleoceanogr., 9: 619-638, 112 text-figs, 3 tabs; Washington/D.C.

ZAGWIJN, W. H. (1989): The Netherlands during the Tertiary and the Quaternary: A case history o f Coastal Lowland evolution. - Geol. Mijnbouw, 68: 107-120, 27 text-figs; Dordrecht.

ZAZmGIN, Vi S. (1980): Gryzuny pozdengo Pliotsena i Antropogena yuga zapadnoj Sibiri. [Rodents of the Pliocene and Anthropogene of Southwestern Siberia.]- 156 p., 39 text-figs, 12 tabs; Moskva (Nauka). - [In Russian.]

13 8 MAUL, REKOVETS, HEINRICH, KELLER ~~91 STORCH: Arvicola mosbachensis (SCHMIDTGEN 1911) o f M o s b a c h 2 : .

P l a t e

1

Figs 1-10. Arvicola mosbachensis (SCHMIDTGEN 19 | |). -- M o s b a c h 2.

' = drawing reversed, b = buccal view, c = basal view, d = distal view, m - m e s i a l view, all other v i e w s are occlusal.

1. S M F 7 4 / 4 8 3 5 . - M / 1 , H o l o t y p e . 2. SMF 74/4843. M / l , Paratype. 3. SMF 74/4835. M / I , Paratype. 4. S M F 9 9 / 1 5 4 3 . M/1. 5. SMF 74/4841. M3/, Paratype. 6. SMF 7 4 / 4 8 4 2 . - M / l , Paratype. 7. SMF 9 9 / 1 5 4 4 . - M/1. 8. SMF 99/1545. M3/. 9. SMF 9 9 / 1 5 4 6 . - M3/. 10. S M F 9 9 / 1 5 4 7 . M3/.

Senckenbergiana lethaea, 80 (1); 2000 Plate 1

i~ '! i

1

l b

3C'

f

l m

2

b , d , m

J

3

3b

3 m

4

2 m m 2 m m

5c

5b'

l c '

5'

5d'

6'

7'

8b'

8'

8c

8d'

9'

10

L. CHR. MAUL, L. REKOVETS, W.-D. HEINRICH, TI-I. KELLER ~% G. STORCH: Arvicola mosbachensis (SCHMIDTGEN 1911) of Mosbach 2: a basic sample for the early evolution of the genus a n d a reference for furthcr biostratigraphical studies

140 MAUL, REKOVETS, HEINRICH, KELLER ~fr SToRcn:Arvicola mosbachensis (SCHMIDTGEN 1911) o f M o s b a c h 2 : .

P l a t e 2

Figs 11-35. Arvicota mosbachensis (SCHMIDTGEN 1911 ). -- M o s b a c h 2.

9 = drawing reversed, b = buccal view, m - m e s i a l view, all other views are occlusal.

11. SMF 99/1548. - M / l . 12. SMF 99/1549. M/1. 13. SMF 99/1550. M/1. 14. S M F 9 9 / 1 5 5 1 , M/1. 15. SMF 99/1552. M/1. 16. S M F 9 9 / 1 5 5 3 . M/1. 17. S M F 9 9 / 1 5 5 4 . M/1. 18. S M F 9 9 / 1 5 5 5 . M/1. 19. SMF 99/1556. M/1. 20. SMF 9 9 / 1 5 5 7 . - M / 1 . 21. S M F 9 9 / 1 5 5 8 . M / I . 22. SMF 99/1559. M / I . 23. SMF 9 9 / 1 5 6 0 . - M / 1 , 24. S M F 9 9 / 1 5 6 1 . M/1. 25. SMF 99/1562. M/1. 26. SMF 9 9 / 1 5 6 3 . - M / 1 . 27. SMF 99/1564. M/1. 28. SMF 9 9 / 1 5 6 5 . - M / I . 29. SMF 9 9 / 1 5 6 6 . - M / 1 . 30. SMF 9 9 / 1 5 6 7 . - M / 1 . 31. S M F 9 9 / 1 5 6 8 . M/1. 32. SMF 99/1569. M/1. 33. SMF 99/1570. M/1. 34. SMF 99/1571. - M / l , 35. SMF 99/1572. - M / I .

S e n c k e n b e r g i a n a lethaea, 80 (1); 2 0 0 0 Plate 2 14 16' l ] ~.- 13' b.m 17' 15 2 m m 2 m m 21m ,o 19 20' 21 22' 23' 24' 25 25b 26' 27 28 29 30 31 32' 33' 34' 35

L. CHR. MAUL, L. REKOVL I S, W.-D. HEINRICH, TH. KELLER & G. STORCH: Arvicola mosbachensis (SCHMIDTGEN I 9 l l ) Of M o s b a c h 2:

1 4 2 MAUL, REKOVETS, HEINRICH, KELLER 8,91 STORCH• Arvicola mosbachensis (SCHMIDTGEN 1911) o f M o s b a c h 2 : .

P l a t e

3

Figs 3 6 - 5 7 . Arvicola mosbachensis (ScHM~DT~EN 1911 ). - M o s b a c h 2.

' = d r a w i n g reversed, b = b u c c a l view, c = b a s a l view, 1 = lingual view, m = m e s i a l view, all o t h e r v i e w s are o c c l u s a l . 36. S M F 9 9 / 1 5 7 3 . - M / 1 . 37. S M F 9 9 / 1 5 7 4 . - M/1. 38. S M F 9 9 / 1 5 7 5 . - M/1. 39. S M F 9 9 / I 5 7 6 . - M / I . 40. S M F 9 9 / 1 5 7 7 . - M / 1 . 41. S M F 9 9 / 1 5 7 8 . - M / 1 . 42. S M F 9 9 / 1 5 7 9 . - M / I . 43. S M F 9 9 / 1 5 8 0 . - M / 1 . 44. S M F 9 9 / 1 5 8 1 . - M / 1 . 45. S M F 9 9 / 1 5 8 2 . - M / I . 46. S M F 9 9 / 1 5 8 3 . M / I . 47. S M F 9 9 / 1 5 8 4 . - M/1. 48. S M F 9 9 / 1 5 8 5 . - M / 1 . 49. S M F 9 9 / 1 5 8 6 . - M/1. 50. S M F 9 9 / 1 5 8 7 . - M / 1 . 51. S M F 9 9 / 1 5 8 8 . - M/1. 52. S M F 9 9 / 1 5 8 9 . - M / I . 53. S M F 9 9 / 1 5 9 0 . M / I . 54. S M F 9 9 / 1 5 9 1 . - M / 1 . 55. S M F 9 9 / 1 5 9 2 . - M/1. 56. S M F 9 9 / 1 5 9 3 . - M/1. 57. S M F 9 9 / 1 5 9 4 . - M / 1 .

Senckenbergiana lethaea, 80 (1); 2000 Plate 3

36'

37'

38'

39

40'

40c

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41

2 m m 2 m m

42

43'

44'

45'

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461

47'

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49

50'

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52

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53'

54'

55

56'

57'

57m'

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i

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L. CHR. MAUL, L. REKOVETS, W.-D. H› Tn. KELLER ~,91 G. STORCH: Atwicola mosbachensis (SCHMIDT(]EN 1911) of Mosbach 2: a basic sample for the early evolution of thc gcnus a n d a rcfcrcnce for further biostratigraphical studies

144 MAUL, REKOVETS, tlEINRICH, KELLER & STORCH: Arvicola mosbachensis (SCHMIOTGEN 1911 ) o f M o s b a c h 2 : .

P l a t e 4

Figs 58-73. Arvicola mosbachensis (SCHMIDTGEN 1911). - Mosbach 2.

' - d r a w i n g reversed, b - buccal view, c = basal view, all other views ate occlusal.

58. SMF 99/1595. - M / l . 59. SMF 9 9 / 1 5 9 6 . - M / 1 . 60. SMF 9 9 / 1 5 9 7 . - M / 1 . 61. SMF 9 9 / 1 5 9 8 . - M / 1 . 62. SMF 9 9 / 1 5 9 9 . - M / 1 . 63. SMF 9 9 / 1 6 0 0 . - M / 1 . 64. SMF 9 9 / 1 6 0 1 . - M / 1 . 65. SMF 9 9 / 1 6 0 2 . - M/1. 66. SMF 99/1603. - M/1. 67. SMF 9 9 / 1 6 0 4 . - M / 1 . 68. SMF 9 9 / 1 6 0 5 . - M / 1 . 69. SMF 9 9 / 1 6 0 6 . - M/1. 70. SMF 9 9 / 1 6 0 7 . - M/1. 71. SMF 9 9 / 1 6 0 8 . - M/1. 72. SMF 99/1609. - M/1. 73. S M F 9 9 / 1 6 1 0 . M/1.

Senckenbergiana lethaea, 80 (1); 2000 Plate 4

58

59'

60'

61c'

2 m m 2 m m i

J

62

63

64'

64c

64b'

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69

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L. CUR. MAUL, L. REKrOVEIS, W.-D. HEINRICH, TH. KI-LLER & G. STOR(H: Arvicola moxbachensis' (SCHMIDTGFN 1911) Of Mosbach 2: a basic sample for the early evolution of the genus a n d a reference for further biostratigraphica[ studies

146 MAUL, REKOVETS, HEINRICH, KELLER 891 STORCH: Arvicola mosbachensis (SCHMIDTGEN 1911) o f M o s b a c h 2 : .

P l a t e

5

Figs 74-91. Arvicola mosbachensis (SCHMIDTGEN 1911). - M o s b a c h 2.

' = drawing reversed, b = buccal view, c = basal view, d = distal view, 1 = lingual view, all other v i e w s are occlusal.

74. SMF 99/1611. - M3/. 75. SMF 99/1612. M3/. 76. SMF 99/1613. M3/. 77. SMF 99/1614. - M3/. 78. SMF 9 9 / 1 6 1 5 . - M 3 / . 79. SMF 99/1616. M3/. 80. SMF 9 9 / 1 6 1 7 . - M 3 / . 81. S M F 9 9 / 1 6 1 8 . M3/. 82. SMF 99/1619. - M3/. 83. SMF 99/1620. - M3/. 84. SMF 99/1621. M3/. 85. SMF 99/1622. - M3/. 86. SMF 99/1623. M3/. 87. SMF 99/1624. - M3/. 88. SMF 99/1625. - M3/. 89. SMF 99/1626. M3/. 90. SMF 99/1627. - M3/. 91. SMF 99/1628. - M3/.

Senckenbergiana lethaea, 80 (1); 2000 PIate 5

74c

74'

75'

76c

9

i

/

74b'

76'

77

78'

79'

79d'

80

81

82'

75 75b ~91

b . d , I 2 m m 2 m m

78c

78b'

82c

83

84'

85

86'

88'

%Jil, !

7

87'

9O1

89

90

90c'

90d

91'

L. CHR. MAUL, L. REKOVETS, W.-D. HEINRICH, T~. KELLER ~91 G. STORCH: Arvicola mosbachensis (SCHMIDTGEN 1911 ) of Mosbach 2: a basic sample for the early evolution of the genus a n d a reference t'or further biostratigraphical studies