A new anosteirine turtle from Manchuria

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FIELDIANA - GEOLOGY

Published by
CHICAGO NATURAL HISTORY MUSEUM

Volume 10 JANUARY 238, 1947 No. 3

A NEW ANOSTEIRINE TURTLE
FROM MANCHURIA

RAINER ZANGERL
CURATOR OF FossIL REPTILES

The Department of Geology (Division of Vertebrate Paleon-
tology) of Chicago Natural History Museum has acquired a small,
fossil turtle through the courtesy of Mr. Tokumatsu Ito, formerly
of the Department of Anthropology, who presented it to the Mu-
seum in 1935 as a gift from the collector, Mr. K. Ogaki. The label
states that the specimen came from the Fu-schun coal mine, near
Fu-schun, province of Fengtien, Northeast Provinces (Manchuria).

Although the extensive coal deposits, coaly shales, and oil shales
of this mine have been the subject of several geological reports
(see Uwatoko, 1930) and have furnished a considerable amount of
fossil plant material, described by Palibin (1906), Florin (1922),
and Endo (1934), I have failed to find any reference to vertebrate
remains from this locality.

The determination of the age of the coal deposits of Fu-schun
apparently rests entirely on paleobotanical evidence. Florin tends
to consider the beds as of Oligocene age, whereas Endé, on the basis
of more material, concludes that they are of late Eocene age. The
latter determination is strengthened by the recognition of an ano-
steirine turtle that is morphologically close to Anosteira ornata and
Anosteira mongoliensis, both of which are late Eocene forms.

Order Testudinata
Family Dermatemyidae
Subfamily Anosteirinae

Anosteira manchuriana sp. nov.

Holotype.—Chicago Natural History Museum No. P15102,
carapace and plastron. The specimen is somewhat flattened in the
dorso-ventral direction. The costal plates of the left side of the shell
presumably retain their original curvature, but, together with the

No. 586 13

14 FIELDIANA: GEOLOGY, VOLUME 10

neurals, are thrust upon the proximal ends of the right costals.
Considerable portions of the costal plates of both sides are broken
away, but they have left sharp impressions in the matrix (fig. 7).
All of the peripheral bones are missing. The plastron is beautifully
preserved except for the distal ends of the hyo- and hypoplastra
(fig. 8). The matrix is a fairly soft, bituminous shale (oil shale?)
of exceedingly fine grain. The bones are well preserved, showing the
finest details of surface sculpture.

Horizon and locality —Late Eocene. Fu-schun coal mine, prov-
ince of Fengtien, Northeast Provinces (Manchuria), probably from
the oil shale horizon.

Diagnosis.—Nuchal plate much wider than long, apparently
convex in front, posteriorly excavated for the reception of the front
end of the first neural. Epiplastra elliptical in outline; lateral edges
of xiphiplastra converging caudad to form a sharp point. Small
fontanelle between hyoplastra and entoplastron.

With the exception of the over-all outline of the shell and the
structure of the peripherals, the morphology can be made out satis-
factorily (figs. 5and 6). On the whole, this species strongly resembles
Anosteira ornata Leidy from the Bridger Eocene of North America,
of which a good shell was figured and described by Hay (1908). The
similarity is particularly great in the surface sculpture, on the basis
of which the two forms could scarcely be distinguished.

The nuchal plate is only partially preserved; its general shape,
however, can be determined by a clear impression left on the matrix.
Its anterior margin appears to be curved ventrad, and its outline, in
dorsal aspect, is that of a yoke. Neurals 1-6 are hexagonal, Nos. 1,
4, and 6 being the widest. The posterior sutural delimitation of the
seventh neural is uncertain. An almost circular eighth neural is
located between the seventh and eighth pairs of costals. The seventh
costal plates are exceptionally wide. This entire region of the shell
is very different from any other anosteirine turtle so far described,
but the frequency of anomalies in the posterior (particularly the
sacral) region of shells of recent pond turtles (e.g. Chrysemys picta)
strongly suggests caution in the interpretation and evaluation of
differences of this kind. For this reason these ‘‘distinguishing”’
characters were omitted from the diagnosis of the present species.

The shield furrows are delicate but clearly visible under suitable
lighting. In the specimen (fig. 7), these scale imprints are not con-
tinuous across adjoining plates, because of a moderate disarrange-
ment of the latter. On costal plates Nos. 2 to 6 the ornamentation

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Fic. 5. Partially reconstructed carapace of Anosteira manchuriana sp. nov.
> a

15

16 FIELDIANA: GEOLOGY, VOLUME 10

Fic. 6. Reconstruction of plastron of A. manchuriana sp. nov. X 1.8.

consists of longitudinal, irregular ridges and valleys, the larger ones
lying next to the neurals. Costals Nos. 1, 7, and 8, the nuchal and
suprapygal, are covered with fine pustules and depressions. The
neurals are fairly smooth.

All elements of the plastron are present. The left epiplastron
could not be brought to view entirely without destruction of the
imprint of the costal plates on the opposite side of the specimen. The

ZANGERL: ANOSTEIRINE TURTLE FROM MANCHURIA 17

left postero-lateral corner of the entoplastron is hidden below the
hyoplastron and the lateral half of the latter lies buried below
the hypoplastron. As in the American Museum specimen (No. 6132)
of Anosteira ornata (Hay, 1908) and in A. mongoliensis Gilmore, the
sutures between the plastral elements are not (or are very weakly)
serrated, in contrast to those of Psewdanosteira pulchra Clark.

MEASUREMENTS
(In millimeters)
Greatest length OF specimen a oo oo ccs ooh nas SR Lae aa ees 85
Greatest width of specimen (at level of third costal plates)............ 57
Widthiofinuchal plate <2. oe cette sotitee rte dee iret renee ceili 24+
Length or HucHal Mate ta GMs lc + Ooi Siecle Oy hr nee alee e iicas 9

NEURAL PLATES

Greatest Width at anterior
No. Length width suture

5.0
5.0
5.4
+5.0
5.8
4.0
5.0

WIDTHS OF COSTAL PLATES AT PROXIMAL ENDS*

No. Left side Right side
I ae re Mere N cated oe eas aur eyy 12.0 13.0
Hie a erg arin eee REE he 9.4 9.4
5 IPRS te tine ie Sis tater 9.2 9.2
Be pccia arte rere rane 29.2 9.2
Bie te eine a itch alerts Meio ae 9.3
Cee eee aa ae 8.0 8.0
Mee en eacavinte iets seh: Seales t 12.8 12.5
Siete cere creetrieame namie tary 4.5 4.5

* The exact lengths of the costal plates cannot be determined, but costals
Nos. 3 and 4 may be estimated at about 37 mm.

PLASTRON
PSGREL OF COOP ONG i seek acta ee ee Pees 80.0
Greatest: width of epiplastroni.. © ois. eee eae een: 11.4
LGROCH-OF CNUODISSUPON. co. oo Lc ee eR er ee ee 17.0
Width of entoplastron at posterior end.................... 10.5 (est.)
Length of hyo- and hypoplastra along suture.............. 28+
Greatest: width‘ot-hyoplastron< = son «pei hos etna bins 10.5

Least: width ot nvoplastroni. -2 ot od) sot Oa ee 4.0
Greatest width of hypoplastron (excluding posterior ‘‘teeth’’) 17.0
LSOKt WiKtH- OF UO PODIOSIION 5 Sse eo oe was ee
Width of hypoplastron along medial suture................
Length of xiphiplastron along midline.....................
Greatest: width of Siphiplastron 0s 5. 6225506545 sce eanaes 8.
Width of posterior plastral lobe at base................... 17

Nore
Non:
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18 FIELDIANA: GEOLOGY, VOLUME 10

Comparison with other species—To date, the following closely
related anosteirine turtles have been described:

Anosteira ornata Leidy, A. radulina Cope, A. anglica Lydekker,
A. mongoliensis Gilmore, and Pseudanosteira pulchra Clark. To
this list should possibly be added Pseudotrionyx pulchra Dollo.!

Anosteira ornata, A. mongoliensis, and Pseudanosteira pulchra
are known either from complete shells or large portions of shells; the
rest are based on isolated fragments. On the basis of what is known
in all three of the better-known forms (the nuchal, hyo-, hypo-, and
xiphiplastra), Anosteira manchuriana and A. ornata appear to be
closer to each other morphologically than either is to A. mongoli-
ensis. However, we have only incomplete knowledge of the Mon-
golian species. A. manchuriana differs from the other two forms in
the apparently convex anterior rim of the nuchal plate.

A comparison of A. ornata, A. manchuriana, and Pseudanosteira
pulchra is of considerable interest. The most peculiar feature of the
genus Anosteira is the extreme reduction or fusion of the vertebral
shields. The first appears to be paired, and extends from the middle
of the nuchal bone back to the second or third pair of costal plates.
The second, third, and fourth vertebral shields are fused into one
long and slender scute wedged anteriorly between the paired first
shields and reaching forward to the first neural plate. The fifth
vertebral shield is normal. Psewdanosteira represents a more primi-
tive condition, since vertebral shields 2, 3, and 4 are separate ele-
ments, though greatly different in size.

In A. ornata, the furrow of vertebral shield 2+3+4 is broadly
rounded in front and does not touch neural plate No. 2. In Pseud-
anosteira, vertebral shield No. 2 is anteriorly pointed and its margin
touches the antero-lateral corners of neural plate No. 2. A. man-
churiana holds an intermediate position; the fused shield 2+3-+4 is
acutely rounded in front, and the furrow crosses the antero-lateral
corners of the second neural plate. The paired vertebral shields No. 1
do not reach back to the third costal plates, as they do in A. ornata
and Pseudanosteira pulchra, but only to the second. Also, the fused
vertebral shield 2+3-+4 is wider than in A. ornata, particularly in
its anterior third. The hind margin of costal shield No. 4 lies on
costal plate No. 7 in the Chinese species, whereas it is situated, for
the most part, on the eighth costal plate in A. ornata and entirely

1Hay (1908) thinks that Pseudotrionyx might belong to the Anosteirinae,

although a re-examination of the type material will be necessary to decide the
matter.

Fic. 7. Unretouched photograph of carapace of A. manchuriana sp. nov. X 1.8.

19

Fig. 8. Unretouched photograph of plastron of A. manchuriana sp. nov. X 1.8.

20

ZANGERL: ANOSTEIRINE TURTLE FROM MANCHURIA 21

on this plate in Pseudanosteira. This difference, however, is per-
haps of little importance, for it may be correlated with the probable
regional irregularity (see above) of the bony shell.

The proportional differences in the plastra of the better-known
anosteirine turtles are given in the following table.

A. ornata A.mongol. A.manch. P. pulchra

Greatest width of hypoplastron (mm.).. 21 21 17 32

Indices*
A=least width of hypoplastron...... 42.8 42.8 38.8 46.8
B=greatest width of hyoplastron.... 52.4 52.4 61.7 56.2
C=least width of hyoplastron....... 16.6 16.6 23.5 25.0
D=length of xiphiplastron.......... 128.0 142.0 134.0 nate
E=proximal width of xiphiplastron. . 47.6 *45.2 47.0 56.2
F=length of epiplastron............ 1 ae ee 17.6 se
G=length of entoplastron.......... SO. @ eho 100.0

* Values A to G X 100/greatest width of hypoplastron paced

REFERENCES
CLARK, JOHN
1932. A new anosteirid from the Uinta Eocene. Ann. Carnegie Mus., 21,
pp. 161-170, 2 figs.
DOoLLo, M. L.
1886. Premiére note sur les Chéloniens du Bruxellien (Eocéne moyen) de la
Belgique. Bull. Mus. Roy. Hist. Nat. Belgique, 4, pp. 75-96, 2 pls.
ENDO, SEIDO
1934. The geological age of the Fu-shun group, South Manchuria. Proc. Imp.
Acad. Japan, 10, pp. 486-489, 1 fig.
FLORIN, RUDOLF
1922. Zur alttertiiiren Flora der siidlichen Mandschurei. Pal. Sinica, (A), 1
pp. 1-45, 3 pls.
GILMORE, C. W.
1931. Fossil turtles of MokoeHa: Bull. Amer. Mus. Nat. Hist., 59, pp. 213-
257, 29 figs., 11 pls.
Hay, O. P.
1908. The fossil turtles of North America. Carnegie Inst. Wash. Pub., 75,
iv+ 568 pp., 704 figs., 113 pls.
LYDEKKER, RICHARD
1889. Catalogue of the fossil Reptilia and Amphibia in the British Museum.
Part 3: Chelonia. London, xviii+ 239 pp., 53 figs.
PALIBIN, J. W.

1906. Fossile Pflanzen aus den Kohlenlagern von Fu-schun in der siidlichen
Mandschurei. Verh. Kais. Russ. Min. Ges., (2), 44.

’

UWATOKO, KUNIO

1930. The oil shale deposit of Fu-shun, Manchuria. Jour. Fac. Sci. Hokkaido
Imp. Univ., (4), 1, pp. 113-205, 38 figs., 13 pls.

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