Palaeobio Palaeoenv (2010) 90:259–273
DOI 10.1007/s12549-010-0031-3
REVIEWS
A review of the Mesozoic turtles of the Junggar Basin
(Xinjiang, Northwest China) and the paleobiogeography
of Jurassic to Early Cretaceous Asian testudinates
Márton Rabi & Walter G. Joyce & Oliver Wings
Received: 12 March 2010 / Revised: 10 May 2010 / Accepted: 31 May 2010 / Published online: 2 August 2010
# Senckenberg, Gesellschaft für Naturforschung and Springer 2010
Abstract Middle Jurassic to Early Cretaceous sediments
exposed in the Junggar Basin have yielded a rich turtle
assemblage. Jurassic taxa include the purportedly basal turtle
Sichuanchelys sp. and at least six basal eucryptodires, which
are currently united in the likely paraphyletic taxon
“Xinjiangchelyidae.” Early Cretaceous assemblages, by
contrast, include a single “xinjiangchelyid” and a single
potential pantrionychian, but are otherwise dominated by
more derived eucryptodires, currently grouped in the paraphyletic taxon “Sinemydidae”/“Macrobaenidae.” Comparison of the Junggar turtle assemblage with those of coeval
This article is a contribution to the special issue “Triassic–Jurassic
biodiversity, ecosystems, and climate in the Junggar Basin, Xinjiang,
Northwest China”
M. Rabi (*)
Department of Paleontology, Eötvös Loránd University,
Pázmány Péter sétány 1/C,
1117 Budapest, Hungary
e-mail: [email protected]
W. G. Joyce
Institut für Geowissenschaften, Universität Tübingen,
Sigwartstraße 10,
72076 Tübingen, Germany
e-mail: [email protected]
W. G. Joyce
Yale Peabody Museum of Natural History,
170 Whitney Avenue,
New Haven, CT 06511, USA
O. Wings
Museum für Naturkunde Berlin,
Leibniz-Institut für Evolutions- und Biodiversitätsforschung
an der Humboldt-Universität zu Berlin,
Invalidenstraße 43,
10115 Berlin, Germany
e-mail: [email protected]
Asian localities reveals that Jurassic turtle assemblages were
rather homogenous throughout the Jurassic, but split in the
Early Cretaceous. In particular, the Early Cretaceous Junggar
turtle assemblage resembles those of other northern Chinese
provinces, Mongolia and the Lake Baikal region of Russia in
their retention of rather basal turtles, whereas all other Asian
localities are dominated by more derived eucryptodires,
particularly pantrionychians. This chasm may be the result of
biogeographic, ecological and climatic conditions, where dry
conditions in isolated inland basins created an ephemeral
lake habitat optimal for basal eucryptodires, whereas the
river environments typical of the surrounding coastal areas
were favourable for more derived eucryptodires.
Keywords Testudines . Xinjiangchelyidae . Junggar Basin .
Jurassic . Cretaceous
Introduction
Freshwater turtles are generally restricted to their aquatic
habitat and may therefore develop patterns of endemism when
their habitat is fragmented. The development of such endemisms was particularly favourable in Central Asia for various
aquatic groups of vertebrates throughout the Jurassic (sensu
Averianov et al. 2005a; Russell 1993), as the available
lacustrine and fluviatile habitat is thought to have been
restricted to numerous basins that were separated by mountain
belts (Zhou and Dean 1996) and influenced by differing
climatic conditions (e.g. Eberth et al. 2001). It remains
unclear, however, if these basins were hermetically sealed
from each other, or if passages along the coasts or within the
mountain belts allowed for the free exchange of populations.
Given that freshwater turtles are among the most common
elements in Central Asian assemblages, a detailed study of
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their taxonomy and palaeogeographical distribution is
expected to clarify whether various Central Asian basins were
connected by lacustrine environments. The Junggar Basin,
with its extensive Mesozoic sediment deposits, has a rich
record of fossil freshwater turtles and has thus proven to be a
key area in improving our understanding of basal eucryptodiran evolution and palaeobiogeography. In this review, we
provide a brief overview of the somewhat confusing
taxonomy and publication history of the Mesozoic freshwater
turtles from the Junggar Basin. We also compare the Junggar
fauna to other Jurassic to Early Cretaceous faunas of Asia and
discuss the observed paleobiogeographical pattern.
The earliest scientific finds of fossil turtle material in the
Junggar Basin were probably made by a Soviet expedition
working in the Tukhun-Kho river basin in the years 1941–
1942. These materials from the Early Cretaceous Tugulu
Group (Hutubin Formation), consisting of shells and imprints,
were soon mislaid, but Khosatzky, based on his study of the
original drawings and photographs made in the 1950s, named
a new species, ?Sinemys efremovi, in a posthumously
published paper (prepared by Nessov and Khosatzky 1996).
The original material was recently rediscovered and referred
to the genus Wuguia (Danilov and Sukhanov 2006). Further
contributions to the study of Early Cretaceous turtles from
the Junggar area were made by Ye (1973), Gaffney and Ye
(1992), Brinkman (2001), Maisch et al. (2003), Matzke et al.
(2004a, b) and Danilov and Parham (2007), which resulted in
the naming or identification of a total of seven taxa.
In May and June of 1989, the expedition of the Sino–
Canadian Dinosaur Project collected several turtle specimens
from the Late Jurassic Qigu Formation at the Pingfengshan
(Wucaiwan) locality in the central Junggar Basin. This material,
corresponding to more than 14 individuals of Xinjiangchelys,
was later described by Peng and Brinkman (1993). The Sino–
German Project, launched in 1999, concentrated on the
southern part of the Junggar basin. Fieldwork around the city
of Urumqi revealed several relatively well-preserved turtle
specimens (mostly shells and other postcranial material) in the
Middle Jurassic Toutunhe Formation, the Late Jurassic Qigu
Formation and the Early Cretaceous Tugulu Group, which
were subsequently described (Maisch et al. 2003; Matzke and
Maisch 2004; Matzke et al. 2004a, b, 2005). In parallel, the
expeditions of an American–Chinese cooperation, led by
James Clark and Xu Xing, has been focusing on the Middle
and Late Jurassic assemblages of the central Junggar Basin. A
brief report on their turtle finds was published recently by
Brinkman and Matzke (2009).
Geological background
The Junggar Basin is a large continental basin located in
Xinjiang Uygur Autonomous Region, Northwest China, that
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contains an up to 6-km-thick succession of Mesozoic sediments
(Dong 1992). Because fossil turtle material has only been
found in Middle and Late Jurassic and Early Cretaceous
sediments, the discussion in this review is mainly restricted to
formations within this time interval. All Jurassic and
Cretaceous strata in the Junggar Basin were deposited in a
complex fluvial–deltaic–lacustrine system. The resulting clastic sedimentary sequences can be stratigraphically subdivided
into several, somewhat inconsistently named formations.
Paleobiogeography and sedimentology
During the Early Jurassic, the Junggar District was covered by
a large lake in which grey-green and grey-black sandstone and
mudstones were deposited (Zhou and Dean 1996). The lake
was surrounded by river drainage systems with shallowwater swamps where coal accumulated along the margins
(Zhou and Dean 1996). The complete Junggar–Turpan–Rami
area was uplifted during the middle Early Jurassic. In the
Middle Jurassic, coinciding with an arid climate, the basin
became narrower, and shallower; the deposits consist mainly
of purple-red and yellow-green sandstones and mudstones,
locally with marlite (Zhou and Dean 1996). This trend
continued in the early Late Jurassic: the lake became still
shallower and smaller; followed by uplift and denudation.
Late Jurassic subsidence resulted in the accumulation of new
lacustrine sediment deposits consisting of red to variegated
sandstones and mudstones (Zhou and Dean 1996). The lake
persisted into the early Early Cretaceous (Wang 1988).
During this time, the Junggar Lake District was dominated
by lacustrine and, locally, fluvial facies, containing purplered and grey-green intercalated sandstones, siltstones and
mudstones (Zhou and Dean 1996). After uplift and erosion
in the middle Cretaceous, a fluvial and locally lacustrine
facies of yellow-brown and purple-red sandstones, conglomerates and mudstones was deposited in the Late Cretaceous
(Zhou and Dean 1996).
Jurassic
The Middle Jurassic Toutunhe Formation in the southern
Junggar Basin consists of alluvial plain deposits, mainly
mudstones and sandstones. The early Late Jurassic Qigu
Formation comprises massive red shales and minor sandstones and also represents alluvial plain sediments. The late
Late Jurassic Kalaza Formation is composed of a planarbedded conglomerate representing a distal alluvial fan-to-fan
delta (Eberth et al. 2001).
In the central and northeastern part of the Junggar Basin,
the equivalent formations are the Shishugou Formation, which
now includes the formerly separate Wucaiwan Formation
(Eberth et al. 2001), and the Kalaza Formation. While the
latter is again composed of a conglomerate and megascale,
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cross-bedded sandstone deposited—according to interpretation—as proximal valley fills with alluvial fans, braided
plain and Aeolian dune sediments (Eberth et al. 2001), the
sedimentology of the former is more complex. The Shishugou Formation is very rich in vertebrate fossils, including
several turtle taxa. It mainly consists of sandstones and
mudstones that are deposited in an alluvial floodplain and a
paludal–lacustrine environment with shallow lakes (Eberth et
al. 2001, 2010; Vincent and Allen 2001).
Cretaceous
Early Cretaceous sediments in the Junggar Basin are united
into the Tugulu Group and distributed along the northern and
southern rims of the basin. The Tugulu Group consists of redgreen, grey-green and variegated or striped sandy mudstones
(Dong 1992), and a large part of this Group consists of
subaerially deposited sediments and fluvio-lacustrine deposits
laid down under semiarid climatic conditions. The Tugulu
Group can be divided into four lithological formations, all of
which have produced vertebrate fossils (Dong 1992): the
Qingshuihe Formation, which consists of grey-green sandstones and basal conglomerates in the lower part and yellowgreen or gray-green sandstones alternating with mudstones in
the upper part; the Hutubin Formation (or Hutubihe Fm.;
Vincent and Allen 2001), which consists of purple mudstones
with gray-green siltstones and sandstones, with large scale
cross-bedding; the Shengjinkou Formation, comprising graygreen calcareous mudstones and shales; the Lianmuqin
Formation, which contains red and green variegated mudstones and arenaceous mudstones, alternating with gray-green
siltstones.
Especially well-preserved vertebrate fossils have been
found within the Tugulu Group in Urhe (Wuerhe), in the
northwestern Junggar Basin and in the Dlunshan region
(Dong 1992).
Systematic review of Junggar Basin turtles
Jurassic turtles
Testudinata Klein, 1760 sensu Joyce et al. 2004
Sichuanchelys Ye and Pi, 1997
Sichuanchelys sp. was recently reported from the Late
Jurassic Shishugou Formation based on three carapaces
(Brinkman and Matzke 2009). The type species,
Sichuanchelys chowi, is from the Early Jurassic of Sichuan
(Ye and Pi 1997) and characterised by the plesiomorphic
retention of mesoplastra. The plastron of the Junggar
specimens are unknown, and their assignment to
Sichuanchelys was based on the presence of extremely
wide rectangular vertebrals (Brinkman and Matzke 2009).
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The phylogenetic affinities of Sichuanchelys chowi are
unclear, and we consequently do not refer it to a taxonomic
category more resolved than Testudinata. Danilov and
Parham (2008) speculated that this taxon may be situated
along the phylogenetic stem of crown Testudines.
Pancryptodira Joyce, Parham and Gauthier, 2004
Eucryptodira Gaffney, 1975 (sensu Gaffney 1984)
“Xinjiangchelyidae” Nessov in Kaznyshkin et al. 1990
“Xinjiangchelyids” are medium-sized (carapace length up to
375 mm) aquatic turtles known from the Middle Jurassic to
Early Cretaceous of Asia. The monophyly of this assemblage
has never been demonstrated, and the vast majority of
characters that are used to diagnose this group (e.g. Sukhanov
2000) are symplesiomorphies when mapped onto global trees
(e.g. Gaffney et al. 2007; Hirayama et al. 2000; Joyce 2007).
As currently circumscribed (e.g. Matzke et al. 2004b),
“Xinjiangchelyidae” is therefore likely paraphyletic relative
to “Sinemydidae”/“Macrobaenidae.” The skull, which has
only been described for Annemys levensis, is characterised by
deep upper and lower temporal emarginations, prefrontals that
contact one another along the midline and the absence of an
interpterygoid vacuity (Sukhanov 2000). Well-preserved
“xinjiangchelyid” skulls from the Late Jurassic Qigu Formation of the nearby Turpan Basin (Wings and Joyce 2009)
reveal that the internal carotid arteries entered at the back of
the skull at the pterygoid/basisphenoid suture, but an open
ventral groove formed by the basisphenoid reveals that the
internal carotid canal was incompletely floored. We speculate
that the poor preservation of the Annemys levensis type skull
obscured this morphology. The shell is low and wide,
posteriorly rounded, a nuchal emargination is present, the
carapace has a ligamentous contact with the plastron, the
axillary and inguinal buttresses laterally contact the peripherals
along grooves, the second to seventh peripherals are thickened
and bent upwards to form a gutter and a pair of reduced
epiplastral processes (i.e. cleithra) is present (Sukhanov 2000).
Xinjiangchelys was erected by Ye (1986a) on the basis of a
carapace and an incomplete plastron with associated pectoral
and pelvic girdles, a distal fragment of a humerus, a femur
and a tibia from the late Middle Jurassic or early Late Jurassic
of the Jiangjunmiao area in the Junggar Basin. The type
species, X. junggarensis Ye, 1986a, b, was later synonymised
by Kaznyshkin et al. (1990) with “Plesiochelys” latimarginalis Young and Chow, 1953 from Sichuan within the genus
Xinjiangchelys. Kaznyshkin et al. (1990) furthermore designated X. latimarginalis as the genotype of Xinjiangchelys.
Following article 67.1.2. of the International Commission of
Zoological Nomenclature (1999), this action is not permissible as “the name of a type species remains unchanged even
when it is a junior synonym or homonym, or a suppressed
name.” X. junggarensis Ye, 1986a, b, therefore remains the
type species of Xinjiangchelys.
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Xinjiangchelys latimarginalis (Young and Chow 1953)
from the Late Jurassic Qigu Formation of the Shishugou
Group [Pingfengshan (Wucaiwan) locality, Junggar Basin] is
known from several shells and other associated postcranial
elements that were described by Peng and Brinkman (1993)
(Fig. 1a, b). These authors provided a revised diagnosis for X.
latimarginalis and supported the synonymy of X. latimarginalis and X. junggarensis. However, Peng and Brinkman
(1993) noted that the type specimen of X. junggarensis differs
from all referred specimens of X. latimarginalis by the
presence of a ninth costal, fused first and second peripherals
and a single suprapygal. On the basis of a phylogenetic
analysis of the Xinjiangchelyidae, Matzke et al. (2004b)
found that “Plesiochelys” latimarginalis was situated rather
basal within their “xinjiangchelyid” ingroup separate from X.
junggarensis. They consequently excluded X. latimarginalis
(sensu Peng and Brinkman 1993) from the genus and
considered X. junggarensis to be a distinct species. Moreover,
Matzke et al. (2004b) differentiated X. latimarginalis sensu
Kaznyshkin et al. (1990) from X. latimarginalis sensu Peng
and Brinkman (1993) and provided a separate diagnosis for
each. Nevertheless, as noted by Danilov and Parham (2008),
the data matrix of Matzke et al. (2004b) lacks appropriate
outgroup taxa, and their conclusions are thus questionable.
While X. junggarensis shows a distinct morphology and may
potentially represent a valid species, “Plesiochelys” latimarginalis and the two morphotypes of X. latimarginalis of
Matzke et al. (2004b) are distinguishable by characters that
are very likely to be subject of individual variation. However,
only a relatively large sample of specimens combined with a
global phylogenetic analysis could clarify the validity of
these taxa. Undescribed material belonging to an extremely
large number of individuals from the Turpan Basin of China
could potentially contribute to our understanding of morphological variation in “xinjiangchelyids” (Wings and Joyce
2009).
The main characteristics of X. latimarginalis include a
carapace length up to 360 mm, a smooth shell surface, a
shallow and wide nuchal emargination, an anteroposteriorly
elongated first peripheral, presence of a contact between the
first suprapygal and the tenth peripheral and a wide,
rectangular anterior plastral lobe (Matzke et al. 2004b;
Peng and Brinkman 1993).
Xinjiangchelys sp. A (sensu Peng and Brinkman 1993)
has been reported from the same Pingfengshan (Wucaiwan)
locality that yielded several specimens of X. latimarginalis.
It is distinct from the latter in its elongated plastral lobes
and narrower bridge area. However, it is represented only
Fig. 1 Examples of fossil turtles recovered from Jurassic sediments in the
Junggar Basin, Xinjiang Autonomous Uygur Region. Xinjiangchelys
latimarginalis (Young and Chow 1953): a carapace and b plastron
redrawn from Peng and Brinkman (1993). Xinjiangchelys qiguensis
Matzke et al., 2004b: c carapace and d plastron redrawn from Matzke et
al. (2004b). Annemys levensis Sukhanov and Narmandakh 2006, based
on material found in Mongolia: e carapace and f plastron redrawn from
Sukhanov (2000). Annemys sp., based on a previously unpublished skull
mentioned by Brinkman and Matzke (2009) from the Junggar Basin: g
dorsal view and h ventral view. Specimens not drawn to scale
Palaeobio Palaeoenv (2010) 90:259–273
by one specimen consisting of a plastron and partial
carapace, and Peng and Brinkman (1993) therefore felt that
the material is inadequate for the erection of a new taxon.
Matzke et al. (2004b) noted that the carapace fragment
originates from the middle portion of the carapace and not
the posterior part. The alleged presence of a ninth costal
and ninth neural is therefore not supported by the available
material, and Xinjiangchelys sp. becomes more similar to
other Xinjiangchelys species, in particular to Xinjiangchelys
qiguensis (Matzke et al. 2004b).
Xinjiangchelys chowi Matzke et al., 2005 was described
from the Middle Jurassic (Callovian) Toutunhe Formation
near the city of Urumqi at the southern margin of the
Junggar Basin. This species is based on a single partial
shell, including an almost complete carapace and the right
hypoplastron (carapace length: 345 mm). According to
Matzke et al. (2005), the two anterolateral carapacial
peripheral fontanelles, a thin plastron with large lateral
fontanelles and a median hypoplastral suture with strong
pegs are autapomorphies of X. chowi. Although all of these
characters could be interpreted as juvenile traits, Matzke et
al. (2005) discounted the possibility that the type specimen
is a juvenile because it is among the largest known
“xinjiangchelyids.” Again, undescribed material from the
Turpan Basin belonging to a large number of individuals
and preliminarily referred to X. cf. chowi may clarify
the validity of this species (Wings and Joyce 2009). The
presence of fontanelles in the carapace and pegs in the
plastron were interpreted by Matzke et al. (2005) as derived
features within the genus, and X. chowi therefore appears to
be the most advanced species of Xinjiangchelys. Given that
this taxon is also one of the oldest “xinjiangchelyids,”
extensive ghost ranges are predicted for all other “xinjiangchelyid” lineages. However, the exact stratigraphic position
of Xinjiangchelys chowi is unclear, and an early Late
Jurassic age is possible.
Xinjiangchelys qiguensis Matzke et al., 2004b originated
from the same region as X. chowi but from the lowermost
part of the overlying Qigu Formation (Late Jurassic,
Oxfordian, Fig. 1c, d). This taxon is therefore contemporaneous with several specimens of X. latimarginalis that
were described by Peng and Brinkman (1993, see above)
from the Shishugou Formation in the Northern Junggar
Basin. The type and only specimen consists of a shell
(carapace length: 375 mm) and a number of associated
postcranial elements, including the scapulae, pelvis, ulna
and nearly all cervical vertebrae. Among others, X.
qiguensis is distinguished from other Xinjiangchelys by
the extension of the first and fifth vertebrals onto the
peripherals, three pairs of gulars and an intergular that does
not contact the hyoplastron. In addition, the shoulder girdle
is unique in the presence of a long acromial process but
short scapular processes, the pelvis has a posterior iliac
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process that is longer than the iliac shaft and the cervicals
are elongated.
According to the phylogenetic analysis of Matzke et al.
(2004b), X. qiguensis is the most basal representative of
Xinjiangchelys and more derived than “P.” latimarginalis.
Plesiomorphic traits include the fifth vertebral extending
strongly onto the peripherals, anteriorly directed axillary
processes, gular scutes that do not extend onto the
hyoplastron, and pectoral scutes that are much smaller than
the abdominal scutes.
Xinjiangchelys radiplicatus (Young and Chow 1953) is a
small turtle (maximum carapace length: 250 mm) based on
two shells from Sichuan (Ye 1986b; Young and Chow 1953)
that were originally described as Plesiochelys radiplicatus, but
later referred to Xinjiangchelys by Kaznyshkin et al. (1990)
and Peng and Brinkman (1993). The first specimens from the
Junggar Basin were reported by Maisch et al. (2003) who
referred an incomplete carapace and plastron together with
other pieces of a small decorated turtle to X. cf. radiplicatus
from the upper Toutunhe Formation (Middle Jurassic) at
Liuhuanggou. Matzke et al. (2004b) later suggested that the
presence of small peripheral fontanelles, a small size and the
distinct sculpture of the shell might be juvenile features and
that the material may represent an already recognised species.
Brinkman and Matzke (2009) recently identified a skull with
associated shell and other isolated plates as cf. X. radiplicatus
(misspelled as “radiplicus”) from the Shishugou Formation.
Thus, the number of decorated turtle specimens is increasing,
and further studies may confirm the validity of this taxon. The
skull reported by Brinkman and Matzke (2009) shows
shallow temporal and cheek emargination and a triangular
basisphenoid similar to that of Chubutemys copelloi from
Argentina (Gaffney et al. 2007). The shell of X. radiplicatus is
decorated with radially oriented ridges and grooves that are
independent from the bony pattern but associated with the
sulci (Matzke et al. 2004b).
Annemys sp. Sukhanov and Narmandakh 2006 is another
turtle taxon from the Junggar Basin that has been reported as
a skull–shell association (Brinkman and Matzke 2009), but a
formal description is still outstanding (Fig. 1e–h). This
possible “xinjiangchelyid” genus was established on the
basis of a partial shell from the Late Jurassic of Sharteg,
Mongolia and includes two species, A. latiens and the A.
levensis, the latter of which is based on a skull–shell
association (Sukhanov and Narmandakh 2006). Matzke et
al. (2004b) considered Annemys latiens to be a junior
synonym of Xinjiangchelys based on a phylogenetic analysis
of the “Xinjiangchelyidae.” All known skulls of Annemys
possess deep temporal and cheek emarginations, as in the
partial skull from the Callovian of Kyrgyzstan referred to X.
latimarginalis (Kaznyshkin et al. 1990), unlike cf. Xinjiangchelys radiplicatus and Xinjiangchelys cf. chowi, the
few other “xinjiangchelyids” for which a skull is known
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(Brinkman and Matzke 2009; Danilov et al. 2005; Sukhanov
2000; Sukhanov and Narmandakh 2006; Wings and Joyce
2009). Together with the presence of a large foramen
palatinum posterius and the narrow vertebrals, Annemys
spp. are more similar to the “macrobaenid” Hangaiemys spp.
from the Early Cretaceous of Mongolia than to Xinjiangchelys (Brinkman and Matzke 2009), thus supporting
the possible paraphyly of the “Xinjiangchelyidae” as
currently constructed.
Early Cretaceous turtles
“Xinjiangchelyidae” Nessov, in Kaznyshkin et al. 1990
Xinjiangchelys sp. B (sensu Danilov and Parham 2007)
from the Early Cretaceous (Aptian–?Albian) upper Tugulu
Group (Wuerho locality) in the southern Junggar Basin is
one of the latest records of “Xinjiangchelyidae,” considerably extending the temporal range of this group from the
Middle–Late Jurassic to the Early Cretaceous. The only
shell of this turtle (carapace length: 230 mm) is the
holotype of the problematic taxon “Sinemys” wuerhoensis
(Ye 1973), which was erected on the basis of a series of
shells and skulls on three slabs of limestone recently
revealed to be a chimera (Danilov and Parham 2007, see
below). Currently, “S.” wuerhoensis is recognised as a
nomen dubium since the type specimen does not show any
autapomorphies and greatly resembles X. latimarginalis
sensu Peng and Brinkman, 1993 (Danilov and Parham
2007). Although X. sp. B differs from X. latimarginalis in
its plastral proportions and the presence of a central
fontanelle variation in Xinjiangchelys is too poorly known,
the specific assignment of the Wuerho specimen is
currently unclear.
“Sinemydidae” Ye, 1963
“Macrobaenidae” Sukhanov, 1964
Most Early Cretaceous eucryptodiran turtles more derived
than “xinjiangchelyids” are often referred to “sinemydids” and/
or “macrobaenids”. However, the monophyly of these two
groups is doubtful, and their taxonomical composition is
therefore controversial (Brinkman 2001; Brinkman and Peng
1993a, b; Gaffney 1996; Gaffney et al. 2007; Gaffney and Ye
1992; Joyce 2007; Parham and Hutchison 2003). We herein
partly follow Gaffney et al. (2007) by collectively referring to
these turtles as “Sinemydidae”/“Macrobaenidae.” Our usage
of this term is nevertheless more restrictive than that of
Gaffney et al. (2007), as we only include turtles formerly
classified as Sinemydidae and Macrobaenidae and not
“xinjiangchelyids” and meiolaniids. Two main skull morphologies are apparent within this group. Sinemys lens is
characterised by extremely deep, confluent upper temporal
and cheek emarginations due to the lack of a temporal bar,
prefrontals that do not meet one another along in the midline,
Palaeobio Palaeoenv (2010) 90:259–273
an elongated basisphenoid and an enclosed incisura columella
auris (Brinkman and Peng 1993a). On the other hand,
Ordosemys spp., Dracochelys bicuspis and Kirgizemys spp.
possess only a moderate upper temporal emargination, but
deep cheek emarginations, medially meeting prefrontals, an
open incisura columellae auris and a short basisphenoid
(Brinkman and Peng 1993a; Danilov et al. 2006; Gaffney and
Ye 1992; Sukhanov 2000; Tong et al. 2004). The shell of
Sinemys spp. is highly aberrant: the pygal bone is absent, the
twelfth peripherals are reduced, a ninth neural is present and
the seventh peripherals are developed into laterally protruding
spines (Brinkman and Peng 1993a).
Wuguia hutubeiensis Matzke et al. 2004a is a recently
described “sinemydid”/“macrobaenid” turtle from the Early
Cretaceous (Hauterivian–Barremian) Hutubei Formation
(Tugulu Group) of the southwestern Junggar Basin (Haojiagou section, Fig. 2a). It is known from several almost
complete and partial shells (carapace length: 137 mm), an
isolated scapula, and an ilium. Wuguia hutubeiensis is
diagnosed from other “sinemydids”/“macrobaenids” by a
unique combination of traits, including the absence of a
nuchal emargination and carapacial fontanelles, at least two
suprapygals, presence of a cervical scute, a ligamentous
connection of the plastron and the carapace, absence of
lateral and central plastral fontanelles and an elongated
posterior plastral lobe. A remarkable feature of this species is
the high degree of individual variation within the nuchal and
suprapygal regions: additional ossifications and unique bone
arrangements are apparent and independent of ontogeny or
sexual dimorphism. Matzke et al. (2004b) suggested that W.
hutubeiensis was characterised by a genetic predisposition
for unusually strong variation in the anterior and posterior
segments of the carapace. Not unexpectedly, the variations
occur with the nuchal, first peripheral and suprapygal, all of
which have been demonstrated by Zangerl (1969) to possess
more variability, perhaps because they are not closely
associated with the axial skeleton.
Wuguia efremovi (Khosatzky 1996) originates from the
Hutubei Formation, just as W. hutubeiensis (Fig. 2b). The
type and only known specimen consists of the imprints and
steinkern of a complete and a partial shell collected in 1941–
1942, originally referred to ?Sinemys efremovi by Khosatzky
(1996) in his posthumously published paper. The specimens
were misplaced until recently, and so Khosatzky (1996)
described this taxon based on photographs and drawings
from the 1950s. Brinkman (2001) later excluded ?S. efremovi
from the genus Sinemys (Wiman 1930) but did not attempt to
clarify its taxonomic position. Danilov and Sukhanov (2006)
recently rediscovered the type material and referred “S.”
efremovi to the genus Wuguia. They based this assignment
on the absence of a nuchal emargination, additional
ossifications in the suprapygal, extension of the 12th
marginals onto the second suprapygal, elongated posterior
Palaeobio Palaeoenv (2010) 90:259–273
265
Fig. 2 Examples of fossil turtles
recovered from Cretaceous
sediments in the Junggar Basin,
Xinjiang Autonomous Uygur
Region. Wuguia hutubeiensis
Matzke et al. 2004a: a carapace
redrawn from Matzke et al.
(2004a). Wuguia efremovi
(Khosatzky 1996): b carapace
redrawn from Maisch et al.
(2003). Ordosemys brinkmania
Danilov and Parham, 2007:
c carapace and d plastron
redrawn from Danilov and
Parham (2007). Dracochelys
bicuspis Gaffney and Ye, 1992: e
carapace redrawn from Brinkman
(2001), f skull redrawn from
Gaffney and Ye (1992).
Specimens not drawn to scale
lobe of the plastron and the similar size (carapacial length:
150 mm). However, they maintained the validity of both
species, as W. efremovi can be distinguished from W.
hutubeiensis on the presence of carapacial and plastral
fontanelles, a midline contact of the eighth costals and the
third vertebral being wider than long and wider than the
fourth and fifth vertebrals. Danilov and Sukhanov (2006)
further synonymised Dracochelys wimani (Maisch et al.
2003), a shell-based taxon from the Lianmuxin Formation
(Wuerho district) of the Tugulu group, with W. efremovi.
Dracochelys bicuspis Gaffney and Ye 1992 from the
Lianmuxin Formation (Wuerho district) is based on a single,
well-preserved cranium (Fig. 2f), which was originally
figured and identified as an “amphichelydian” by Ye
(1973). Although Gaffney and Ye (1992) did not undertake
a formal phylogenetic analysis, they nevertheless noted
similarities with Hangaiemys hoburensis, a “sinemydid”/
”macrobaenid” turtle from the Early Cretaceous of Mongolia. Brinkman (2001) referred a partial skeleton to D.
bicuspis (Fig. 2e) based on the presence of a symphyseal
hook, narrow triturating surface, and the size of the lower
jaw, but given that the skeleton lacks the cranium, this
assignment has to be viewed with caution. D. bicuspis has a
flattened skull, narrow triturating surfaces, large foramina
palatinum posterius, large internal nares, and a ninth neural,
which is crossed by the sulcus between the fourth and fifth
vertebrals. All of these traits are shared with Hangaiemys
hoburensis. An autapomorphic character of D. bicuspis is the
presence of a tooth-like process on the lateral surface of the
premaxilla–maxilla suture. With its 45-mm-long skull, this
species is the largest among the Tugulu group turtles. As
mentioned by Gaffney and Ye (1992), the proportions and
shape of the skull and the narrow, hooked beak are strongly
reminiscent of the extant North American snapping turtle
Chelydra serpentina, and D. bicuspis possibly occupied a
similar ecological niche as recent snapping turtles do.
The majority of specimens that comprise the type series of
“S. wuerhoensis” (see above) are now referred to Ordosemys
brinkmania Danilov and Parham, 2007 (Fig. 2c, d). This
taxon is represented by a number of skulls and shells, some
of which are in association. Although the skulls are
deformed, and sutures are not very well preserved, they
share with other species of Ordosemys the absence of a
median prefrontal contact as a result of a long anterior
process of the frontals. Furthermore, the shell (carapace
length: 153–215 mm) possesses a preneural bone and three
suprapygals. Ordosemys brinkmania differs from other
species of this genus in the deeper temporal emargination,
the anterior projection of the first vertebral, and the absence
of a hypo–xiphiplastral fontanelle. Ordosemys is a diverse
and widespread genus in the Early Cretaceous of China and
Mongolia, but only O. brinkmania has been reported from
the Junggar Basin.
Pantrionychia Joyce, Parham and Gauthier, 2004
cf. Pantrionychia indet. is the third taxon that forms part
of the original type series of “S. wuerhoensis” (Danilov and
Parham 2007). It is based on a single, poorly preserved
266
skull only visible in dorsal aspect. Only the parietal–parietal
and the parietal–supraoccipital sutures are visible, and most
of the left side of the skull is eroded. This specimen is
characterised by deep temporal emarginations, short postorbitals and dorsally oriented orbits, and is therefore
strongly reminiscent to extant trionychians.
Relationships of Junggar Basin turtles
The basalmost turtle of the Junggar Basin is likely
Sichuanchelys (Brinkman and Matzke 2009), which has
been argued to be a stem-testudine by Danilov and Parham
(2008), possibly close to Kayentachelys aprix.
The interpretation of “Xinjiangchelyidae” as basal eucryptodires is widely accepted in the literature, and most authors
consider this clade to be more closely related to modern
cryptodires than Paracryptodira or Plesiochelyidae (Gaffney
1996; Hirayama et al. 2000; Joyce 2007; Parham and
Hutchison 2003) and, with the exception of Danilov and
Parham (2008), basal to “Sinemydidae”/“Macrobaenidae”.
Hirayama et al. (2000) concluded that the European taxon
Brodichelys brodei may be a close relative of “Xinjiangchelyidae,” whereas Danilov and Parham (2008) noted close
relationships with Asian Chengyuchelys spp. As it stands, all
global analyses hand pick a select number of one or two
“xinjiangchelyids” (e.g. Danilov and Parham 2008; Gaffney
1996; Hirayama et al. 2000; Joyce 2007; Parham and
Hutchison 2003), and all “xinjiangchelyid” analyses are
highly limited in their taxon sample (e.g. Matzke et al.
2004b; Peng and Brinkman 1993). Finally, the vast majority
of characters typically listed as diagnostic for the group
represent symplesiomorphies for Eucryptodira (e.g. Danilov
and Parham 2008; Gaffney 1996; Hirayama et al. 2000;
Joyce 2007; Parham and Hutchison 2003). It is therefore
highly plausible that “Xinjiangchelyidae” as currently constructed is paraphyletic.
Most Early Cretaceous turtles from the Junggar Basin are
referable to “Sinemydidae” and/or ”Macrobaenidae,” a paraphyletic assemblage of basal eucryptodiran turtles more
derived than “xinjiangchelyids” and typically resolved as the
successive sister taxa of Polycryptodira (sensu Gaffney 1996)
or crown Cryptodira (Joyce et al. 2004). These forms are
generally known from the Cretaceous and Paleogene of Asia
and North America (Brinkman 2001; Brinkman and Peng
1993a; Gaffney and Ye 1992; Parham and Hutchison 2003;
Sukhanov 2000). The paraphyly of “sinemydids” marcobaenids” has been recently confirmed by the phylogenetic
analyses of Gaffney et al. (2007) and Joyce (2007). Among
others, the topology of Gaffney et al. (2007) differs from that
of Joyce (2007) in that Ordosemys leios is not sister to
Sinemys lens and primitive to Dracochelys bicuspis. As
currently understood, the closest relatives of the Junggar
Palaeobio Palaeoenv (2010) 90:259–273
“sinemydids”/“macrobaenids” come from the Jurassic–Cretaceous of Mongolia, China, Russia and Kyrgyzstan (Brinkman
and Peng 1993a; Danilov et al. 2006; Nessov and Khosatzky
1973, 1981). The fact that “Xinjiangchelyidae, “Sinemydidae” and “Macrobaenidae” form successively internested
paraphyletic groups, coupled with the fact that the vast
majority of taxa attributable to these grades are Asian,
strongly confirms the notion that the stem evolution of crown
Cryptodira occurred in Asia.
Palaeobiogeography
The Middle to Late Jurassic turtle assemblages of the
Junggar Basin almost exclusively consist of “xinjiangchelyids”, with the exception of Sichuanchelys sp., a
possible stem-testudine. This composition is comparable
to other Asian assemblages, including the adjacent Turpan
Basin in Xinjiang (Xinjiangchelys cf. chowi, Annemys cf.
latiens), Sichuan (Xinjiangchelys spp., Chengyuchelys
spp.), Mongolia (Annemys spp., Shartegemys laticentralis, Undjulemys platensis), Russia (Xinjiangchelys sp.),
Thailand (Siamochelys peninsularis) and Kyrgyzstan
(Xinjiangchelys spp.), where “xinjiangchelyids” are the
dominant, or in most cases, the sole elements of the
assemblage (Danilov et al. 2005; Danilov and Parham 2008;
Kaznyshkin 1988; Kaznyshkin et al. 1990; Sukhanov 2000;
Sukhanov and Narmandakh 2006; Tong et al. 2002; Wings
and Joyce 2009; Ye 1963, 1986b; Young and Chow 1953).
Within the Jurassic, more derived eucryptodires are only
known from Shandong (Sinemys lens) and Sichuan (the
pantrionychid Yehguia tatsuensis and Sinaspiderites wimani)
(Brinkman and Peng 1993a; Danilov and Parham 2006;
Young and Chow 1953). As currently understood, the
Junggar Basin has produced the most diverse Jurassic turtle
assemblage in Asia, and a number of endemisms are
apparent at the species level (Table 1).
The late Early Cretaceous (Barremian–Aptian) turtle
assemblages of the Junggar Basin almost exclusively consist
of basal eucryptodires, predominately “sinemydids” and/or
“macrobaenids”. Other approximately coeval localities of
China show the same taxonomic distribution: the Barremian–
Aptian Yixian Formation yielded remains of Ordosemys
liaoxiensis and Manchurochelys manchoukuoensis, the Hauterivian–Albian Luohandong Formation yielded Sinemys
gamera and Ordosemys leios and the assemblage from the
Barremian–Aptian Xinminbao Group is characterised by the
“sinemydid”/“macrobaenid” Kirgizemys kansuensis (Bohlin
1953; Brinkman and Peng 1993a, b; Sukhanov 2000; Tong
et al. 2004; Table 2, Fig. 3). Sinochelyids, a possibly basal
group of turtles not closely related with Eucryptodira
(Hirayama et al. 2000), are known from the Aptian of
Shandong and the Albian of Gansu (Peishanemys laptions
Note that basal eucryptodires are widespread through a large part of Asia during the Middle and Late Jurassic
ST: Stem-Testudines; SI: Sinochelyidae; PT: Pantrionychia
All taxa are basal eucryptodires (“xinjiangchelyids” and “sinemydid”/“macrobaenids”) except where noted
8
Young and Chow (1953); 8 *Young and Chow (1953), Ye (1986b); 9 Ye (1999); 10 Ye (1963), Danilov and Parham (2008); 11 Young and Chow (1953), Danilov and Parham (2008); 12 Ye (1994); 13 Wiman (1930),
Peng and Brinkman (1993), Sukhanov (2000); 14 Sukhanov (2000), Sukhanov and Narmandakh (2006); 15 Danilov et al. (2005); 16 Tong et al. (2009a); 17 Tong et al. (2002); 18 Kaznyshkin (1988); Kaznyshkin et al.
(1990); 19 cf. Shachemydinae sensu Nessov (1984), Xinjiangchelys sp. according to Igor Danilov (personal communication)
Numbers correspond to references 1 Brinkman and Matzke (2009); 2 Ye (1986a); 3 Matzke et al. (2004b), 4 Peng and Brinkman (1993); 5 Matzke et al. (2005); 6 Maisch et al. (2003); 7 Wings and Joyce (2009);
Table 1 Temporal and geographic distribution of Jurassic turtle faunas of Asia
Palaeobio Palaeoenv (2010) 90:259–273
267
Note that the paleogeographically inland areas are dominated by basal eucryptodiran turtles
SI: Sinochelyidae; PT: Pantrionychia; PTE: Pantestudinoidea
All taxa are basal eucryptodires (“xinjiangchelyds” and “sinemydid”/”macrobaenids”) except where noted
Maisch (2004); 5 Khosatzky (1996), Danilov and Sukhanov (2006); 6 Bohlin (1953), Danilov et al. (2006); 7 Ye (1965), Danilov and Vitek (2009); 8 Brinkman and Peng (1993a); 9 Brinkman and Peng (1993b),
Brinkman and Wu (1999); 10 Tong et al. (2004); 11 Endo and Shikama (1942), Sukhanov (2000); 12 Chow (1954); 13 Danilov and Syromyatnikova (2008); 14 Nessov (1981); 15 Sukhanov and Narmandakh
(1974), Sukhanov (2000), Danilov et al. (2006); 16 Shuvalov and Chkhikvadze (1979), Sukhanov 2000, Danilov et al. 2006; 17 Khand et al. (2000), Sukhanov (2000), Sukhanov and Narmandakh (1974);
18
Sukhanov (2000), Sukhanov and Narmandakh (2006), Danilov et al. (2006); 19 Sukhanov (2000), Sukhanov and Narmandakh (2006), Danilov and Parham (2007); 20 Khosatzky (1999)
Numbers correspond to references 1 Danilov and Parham (2007); 2 Gaffney and Ye (1992), Brinkman (2001); 3 Maisch et al. (2003), Danilov and Sukhanov (2006); 4 Matzke et al. (2004a), Matzke and
Table 2 Temporal and geographic distribution of Early Cretaceous turtle faunas of China and Mongolia (paleogeographically inland areas)
268
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269
Fig. 3 Paleobiogeography of
turtles during the Early Cretaceous
in Asia. From Shandong (China),
Övörkhangai (Mongolia) and
South Korea only one taxon has
been described (Peishanemys laptions, Nanhsiungchelydae indet.
and Kirgizemys cf. K. exaratus,
respectively). Black areas are lacustrine facies, grey areas are
fluvial and/or coastal facies. Note
that the distribution and dominance of basal eucryptodires are
linked to lacustrine environments
which, with the exception of
South Korea, were typical for the
arid-semiarid inland areas. Pantrionychians, on the other hand,
dominated the fluvial environments along the coastal areas.
This pattern is not apparent for the
Jurassic when lacustrine habitats
were also present close to the
coasts (in Thailand and Kyrgyzstan), and basal eucryptodires
were the most diverse and abundant turtles of Asia. Base map
(120 Ma, Aptian) courtesy of Ron
Blakey. For references on distribution, see caption of Table 2
Bohlin, 1953; Chow 1954; Sukhanov 2000). On the other
hand, pantrionychians are very rare, known only from the
Junggar Basin (cf. Pantrionychia indet. sensu Danilov and
Parham, 2007) and Inner Mongolia (“Aspideretes” spp.;
Danilov and Vitek 2009; Ye 1965). Early Cretaceous
pantestudionids have only been reported from the Aptian of
Mongolia (Mongolemys sp.; Khand et al. 2000; Sukhanov
2000; Sukhanov and Narmandakh 1974). Basal eucryptodires and sinochelyids are also dominant elements in the
Early Cretaceous of Mongolia, including Sinochelys spp.,
Peishanemys testudiformis, Kirgizemys hoburensis (= Hangaiemys hoburensis according to Danilov et al. 2006), K. leptis
and Ordosemys perforata (= Asiachelys perforata according
to Danilov and Parham 2007), ranging from the Aptian to
the Albian (Sukhanov and Narmandakh 1974; Shuvalov
and Chkhikvadze 1979; Sukhanov 2000; Sukhanov and
Narmandakh 2006). Kirgizemys is also well known from
Barremian to Albian deposits in the Lake Baikal region of
Russia (Danilov et al. 2006; Nessov and Khosatzky 1981).
The Early Cretaceous Junggar assemblage is considered to
be partly endemic, even at the generic level, given that only
Ordosemys and Xinjiangchelys have been hitherto reported
outside of the basin (Tables 2 and 3, Fig. 3).
Contrary to China, Mongolia and the Lake Baikal region
of Russia, other late Early Cretaceous Asian turtle
assemblages, including those of Japan, Laos, Thailand and
Kyrgyzstan were characterised by adocid and nanhsiungchelyid trionychians and, perhaps questionably, by stemtestudinoids during the Barremian–Albian, with a very few
basal eucryptodires such as Kirgizemys exaratus (Danilov
and Parham 2007; de Lapparent de Broin 2004; Hirayama
et al. 2000; Tong et al. 2009b; Tables 2 and 3, Fig. 3).
Interrelated geographic, ecological and climatic factors
should be taken into account for possible explanations of
this distributional pattern. During the Early Cretaceous,
northern China, Mongolia and the Lake Baikal region of
Russia were inland areas, while Japan, Laos and Thailand
represented the eastern and Kyrgyzstan the western coastal
region (Fig. 3). It is therefore possible that the descendents
of formerly widespread basal eucryptodiran stock were
isolated during the Early Cretaceous in these inland areas
and retained their relatively conservative morphology and
habitat preferences until the late Early Cretaceous.
In terms of the depositional environment, those Jurassic–
Early Cretaceous strata of Asia which were dominated by basal
eucryptodiran turtles (corresponding to almost exclusively
inland areas) were dominantly characterised by extensive
lacustrine sedimentation (Averianov et al. 2003, 2005a, b;
Bohlin 1953; Dong 1992; Eberth et al. 2001; Jerzykiewicz
2000; Khand et al. 2000; Khosatzky 1996; Lee et al. 2009;
Note that the paleogeographically coastal areas are dominated by pantrionychian turtles
BE: basal eucryptodire
All taxa belong to pantrionychians except where noted
Numbers correspond to references 1 Nessov and Khosatzky (1981), Danilov et al. (2006); 2 Danilov et al. (2006); 3 Tong et al. (2005), (2009b); 4 Tong et al. (2009b); 5 Tong et al. (2006), (2009b); 6 Tong et al.
(2009b); 7 Lapparent de Broin (2004); 8 Lee et al. (2009); 9 Hirayama (2002); 9 *Hirayama (2002), Danilov and Syromyatnikova (2008); 10 Sonoda and Hirayama (2009); 11 Nessov and Khosatzky (1973); 12 Nessov
and Khosatzky (1977); 13 Nessov (1995)
Table 3 Temporal and geographic distribution of Early Cretaceous turtle faunas of Russia, Thailand, Laos, South Korea, Japan and Kyrgyzstan (paleogeographically coastal areas with the
exception of Russia)
270
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Sinithsenkova 2002; Sukhanov and Narmandakh 1974;
Swisher et al. 1999; Tong et al. 2002; Wings and Joyce
2009; Fig. 3). On the other hand, the coastal environments
dominated by pantrionychians were characterised by fluvial
sedimentation (Hirayama et al. 2000; Hirayama 2002; Isaji et
al. 2006; Lapparent de Broin 2004; Tong et al. 2002, 2006,
2009a, b; Fig. 3). Similar to their extant descendents,
pantrionychians were likely excellent swimmers and better
adapted to high-energy riverine conditions. By contrast, it
appears that the more generalised basal eucryptodires
preferred low-energy lakes and swamps. In accordance with
this, Peng and Brinkman (1993) noted that the lacustrine
facies of the Late Jurassic Qigu Formation at Pingfengshan
(Wucaiwan) contrasts with the coeval fluvial facies of
Jiangjunmiao (100 km to the east) in the complete dominance
of turtle remains in the former. The presence of Dracochelys
bicuspis, a possible ecomorphological equivalent to the
Recent North American snapping turtle Chelydra serpentina (Gaffney and Ye 1992), in the former lake of the
Junggar Basin is also consistent with this hypothesis. The
discovery of Kirgizemys cf. K. exaratus in the highlatitude Lower Cretaceous lacustrine facies of South
Korea (Lee et al. 2009) confirms that the distribution of
basal eucryptodires was more linked to paleoenvironment
than to paleogeography (Fig. 3).
Finally, climatic conditions likely also influenced this
biogeographical pattern as the seasonally arid climate in the
inland areas favoured the development of semi-permanent
lakes, while the humid climate in the coasts favoured the
formation of large river systems.
Summary
The high diversity of taxa, the favourable taphonomic
conditions, and the long time span ranging from the Middle
Jurassic to the Early Cretaceous make the Junggar Basin a key
area in our understanding of basal eucryptodiran relationships
and provide insight into a particularly important period of
cryptodiran evolution. The extreme longevity of this extensive, partly isolated, lake-dominated basin provides an ideal
opportunity to study palaeobiogeography and endemisms of
Mesozoic turtles in Asia. As currently known, the Junggar
Basin yields the most diverse pre-Late Cretaceous turtle
assemblages in Asia and, contrary to the regionally extensive
record of Mongolia, the turtle assemblage is derived from a
considerably small area.
The composition and the relict nature of the Junggar
turtle assemblage as well as other inland turtle assemblages
may indirectly infer, together with sedimentological evidence, that the origin of basal eucryptodires primarily took
place in lacustrine environments. Based on their distribution pattern, basal eucryptodires presumably also never
271
became dominant elements in subsequent fluvial habitats.
Although the skeletal anatomy of most basal eucryptodires
confirms this assertion, there are some exceptions. For
instance, the relatively large size of Anatolemys spp.
probably allowed them to inhabit fluvial and estuarine
environments (Nessov 1985, 1987), while Sinemys gamera
and S. lens from the Ordos Basin developed a pair of
posterolaterally directed carapacial spines that may have
had a hydrodynamically stabilising function in higher
energy environments (Brinkman and Peng 1993a).
Although the turtles from the Junggar Basin have been
studied for more than 70 years, with increased intensity in
the last 20 years, much work is yet to be done. Further
clarification of the phylogenetic relationships, intraspecific
variation, paleocology and paleobiogeography are expected
to be rewarding tasks for future researchers.
Acknowledgements We would like to thank Don Brinkman, Igor
Danilov and Thomas Martin for thoughtful comments and discussions
that helped improve the quality of this manuscript. Don Brinkman is
furthermore thanked for providing us with photographs and line
drawings of an unpublished Annemys skull from the Junggar Basin,
which served as the basis of our line drawing presented in Fig. 1g, h.
References
Averianov AO, Starkov A, Skutschas PP (2003) Dinosaurs from the
Early Cretaceous Murtoi formation in Buryatia, Eastern Russia. J
Vertebr Paleontol 23(3):586–594
Averianov AO, Martin T, Bakirov AA (2005a) Pterosaur and dinosaur
remains from the Middle Jurassic Balabansai Svita in the Northern
Fergana Depression, Kyrgyzstan (Central Asia). Palaeontology
48:135–155
Averianov AO, Lopatin AV, Skutschas PP, Martynovich NV, Leshchinskiy
SV, Rezvyi AS, Krasnolutskii SA, Fayngertz AV (2005b) Discovery
of Middle Jurassic mammals from Siberia. Acta Paleontol Pol
50:789–797
Bohlin B (1953) Fossil reptiles from Mongolia and Kansu. Reports
from the scientific expedition to the North-western provinces of
China under leadership of Dr. Sven Hedin, part 4. Vertebrate
palaeontology 6. Sino-Swedish Expedition Publ 37:1–113
Brinkman DB (2001) New material of Dracochelys (Eucryptodira:
Sinemydidae) from the Junggar Basin, Xinjiang, People's
Republic of China. Can J Earth Sci 38:1645–1651
Brinkman DB, Matzke AT (2009) New turtle specimens from the Jurassic
Shishugou Formation of Xinjiang, China. In: Abstr Gaffney turtle
Symp. Royal Tyrell Museum, Drumheller, pp 23-24
Brinkman DB, Peng J-H (1993a) New material of Sinemys (Testudines,
Sinemydidae) from the Early Cretaceous of China. Can J Earth Sci
30:2139–2152
Brinkman DB, Peng J-H (1993b) Ordosemys leios, n. gen., n. sp., a
new turtle from the Early Cretaceous of the Ordos Basin, Inner
Mongolia. Can J Earth Sci 30:2128–2138
Brinkman DB, Wu X-C (1999) The skull of Ordosemys, an Early
Cretaceous turtle from Inner Mongolia, People’s Republic of
China, and the interrelationships of Eucryptodira (Chelonia,
Cryptodira). Paludicola 2:134–147
Chow MC (1954) Cretaceous turtles from Laiyang Shantung. Acta
Palaeontol Sin 2:395–410
272
Danilov IG, Parham JF (2006) A redescription of 'Plesiochelys
tatsuensis' from the late Jurassic of China, with comments on
the antiquity of the crown clade Cryptodira. J Vertebr Paleontol
26:573–580
Danilov IG, Parham JF (2007) The type series of 'Sinemys'
wuerhoensis, a problematic turtle from the Lower Cretaceous of
China, includes at least three taxa. Palaeontology 50:431–444
Danilov IG, Parham JF (2008) A reassessment of some poorly known
turtles from the Middle Jurassic of China, with comments on the
antiquity of extant turtles. J Vertebr Paleontol 28:306–318
Danilov IG, Sukhanov VB (2006) A basal eucryptodiran turtle "Sinemys"
efremovi (= Wuguia efremovi) from the Early Cretaceous of China.
Acta Paleontol Pol 51:105–110
Danilov IG, Syromyatnikova EV (2008) New materials on turtles of
the family Nanhsiungchelyidae from the Cretaceous of Uzbekistan and Mongolia, with a review of the nanhsiungchelyid record
in Asia. Proc Zool Inst Russ Acad Sci 312:3–25
Danilov IG, Vitek NS (2009) Cretaceous trionychids of Asia: A
review of record and biogeography. In: Abstr Gaffney turtle
Symp. Royal Tyrell Museum, Drumheller, pp 52-58
Danilov IG, Obraztsova EM, Krasnolutskij SA, Leshchinskij SV (2005)
On the systematic position of a turtle from the Middle Jurassic of
Krasnoyarsk region. In: Modern Paleontology: classic and newest
methods. The second All-Russian Scientific School for Young
Scientists in Paleontology. Abstracts (in Russian). Paleontological
Institute of the Russian Academy of Sciences, Moscow, pp 24–25
Danilov IG, Averianov AO, Skutchas PP, Rezvyi AS (2006)
Kirgizemys (Testudines, Macrobaenidae): new material from the
Lower Cretaceous of Buryatia (Russia) and taxonomic revision.
Fossil Turtle Res 1:46–62
de Lapparent de Broin F (2004) A new Shachemydinae (Chelonii,
Cryptodira) from the Lower Cretaceous of Laos: preliminary
data. C R Palevol 3:387–396
Dong Z-M (1992) Dinosaurian faunas of China. China Ocean Press,
Beijing
Eberth DA, Brinkman DB, Chen P, Yuan F, Wu S, Li G, Cheng X (2001)
Sequence stratigraphy, paleoclimate patterns, and vertebrate fossil
preservations in Jurassic-Cretaceous strata of the Junggar Basin,
Xinjiang autonomous region, People's Republic of China. Can J
Earth Sci 38:1627–1644
Eberth DA, Xu X, Clark JM (2010) Dinosaur death pits from the
Jurassic of China. Palaios 25:112–125
Endo R, Shikama T (1942) Mesozoic reptilian fauna in the Jehol
mountainland, Manchoukuo. Bull Cent Natl Mus Manchoukuo
3:1–19
Gaffney ES (1975) A phylogeny and classification of the higher
categories of turtles. Bull Am Mus Nat Hist 155:387–436
Gaffney ES (1984) Historical analysis of theories of chelonian
relationship. Syst Zool 33:283–301
Gaffney ES (1996) The postcranial morphology of Meiolania
platyceps and a review of the Meiolaniidae. Bull Am Mus Nat
Hist 229:1–166
Gaffney ES, Ye X (1992) Dracochelys, a new cryptodiran turtle from
the Early Cretaceous of China. Am Mus Novit 3048:1–13
Gaffney ES, Rich TH, Vickers-Rich P, Constantine A, Vacca R, Kool L
(2007) Chubutemys, a new eucryptodiran turtle from the Early
Cretaceous of Argentina, and the relationships of the Meiolaniidae.
Am Mus Novit 3599:1–35
Hirayama R (2002) Preliminary report of the fossil turtles from the
Kitadani Formation (Early Cretaceous) of the Tetori Group of
Katsuyama Prefecture, Fukui Prefecture, Central Japan (in
Japanese with English abstract). Mem Fukui Prefectural Dinosaur
Mus 1:29–40
Hirayama R, Brinkman DB, Danilov IG (2000) Distribution and
biogeography of non-marine Cretaceous turtles. Russ J Herpetol
7:181–198
Palaeobio Palaeoenv (2010) 90:259–273
International Trust for Zoological Nomenclature (1999) International
Code of Zoological Nomenclature. International Trust for
Zoological Nomenclature, London
Isaji S, Matsushita A, Hirayama R (2006) Chelonian eggshells from
the Lower Cretaceous Kuwajima Formation of the Tetori Group,
Central Japan. Paleontol Res 10:29–36
Jerzykiewicz T (2000) Lithostratigraphy and sedimentary settings of
the Cretaceous dinosaur beds of Mongolia. In: Benton MJ,
Shishkin MA, Unwin DM, Kurochkin EN (eds) The age of
dinosaurs in Russia and Mongolia. Cambridge University Press,
Cambridge, pp 279–296
Joyce WG (2007) Phylogenetic relationships of Mesozoic turtles. Bull
Peabody Mus Nat Hist 48:3–102
Joyce WG, Parham JF, Gauthier JA (2004) Developing a protocol for
the conversion of rank-based taxon names to phylogenetically
defined clade names, as exemplified by turtles. J Paleontol
78:989–1013
Kaznyshkin MN (1988) Late Jurassic turtles of northern Fergana
(Kirghiz SSR) (in Russian). Vestnik Zoologii 5:26–32
Kaznyshkin MN, Nalbandyan LA, Nessov LA (1990) Middle and
Late Jurassic turtles of Fergana (Kirghiz SSR) (in Russian).
Yezhegodnik Vsesoyuznogo Paleontologicheskogo Obshchestva
(Annu All-union Palaeontol Soc) 33:185–204
Khand Y, Badamgarav D, Ariunchimeg Y, Barsbold R (2000)
Cretaceous system in Mongolia and its depositional environments. In: Okada H, Mateer NJ (eds) Cretaceous environments of
Asia. Elsevier Science, Amsterdam, pp 49–79
Khosatzky LI (1996) New turtle from the Early Cretaceous of Central
Asia. Russ J Herpetol 3:89–94
Khosatzky LI (1999) Trionychid turtles of the Cretaceous of Mongolia
(in Russian). Vopr Paleontol 11:141–149
Klein IT (1760) Klassification und kurze Geschichte der vierfüßigen Thiere (translated by F. D. Behn). Jonas Schmidt,
Lübeck
Lee Y-N, Hutchison JH, Chang K-H (2009) The first Mesozoic turtle
from South Korea. Cret Res 30:1287–1292
Maisch M, Matzke A, Sun G (2003) A new sinemydid turtle (Reptilia:
Testudines) from the Lower Cretaceous of the Junggar Basin
(NW-China). N Jb Geol Paläont, Mh 12:705–722
Matzke AT, Maisch MW (2004) New information and specimens of
Wuguia hutubeiensis (Reptilia: Testudines) from the Lower
Cretaceous Tugulu Group of the southern Junggar Basin (NW
China). N Jb Geol Paläont, Mh 2004:473–495
Matzke AT, Maisch MW, Pfretzschner H-U, Ge S, Stöhr H (2004a) A
new basal sinemydid turtle (Reptilia: Testudines) from the Lower
Cretaceous Tugulu Group of the Junggar Basin (NW China). N
Jb Geol Paläont, Mh 2004:151–167
Matzke AT, Maisch MW, Sun G, Pfretzschner H-U, Stöhr H (2004b)
A new xinjiangchelyid turtle (Testudines, Eucryptodira) from the
Jurassic Qigu Formation of the southern Jungar Basin, Xinjiang,
North-West China. Palaeontology 47:1267–1299
Matzke AT, Maisch MW, Sun G, Pfretzschner H-U, Stöhr H (2005) A
new Middle Jurassic xinjiangchelyid turtle (Testudines; Eucryptodira) from China (Xinjiang, Junggar Basin). J Vertebr Paleontol
25:63–70
Nessov LA (1981) On turtles of the family Dermatemydidae from the
Cretaceous of the Amur river basin, and some other rare
discoveries of the remains of ancient turtles of Asia (in Russian).
In: Borkin LJ (ed) Herpetological research in Siberia and the Far
East. Zoological Institute of the Academy of Sciences USSR,
Leningrad, pp 69-73
Nessov LA (1984) Data on late Mesozoic turtles from the USSR.
Studia Geologica Salmaticensia. Stud Palaeocheloniol 1:215–223
Nessov LA (1985) Some late Mesozoic and Paleocene turtles of
Soviet Middle Asia. Studia Geologica Salmaticensia. Stud
Palaeocheloniol 2:7–22
Palaeobio Palaeoenv (2010) 90:259–273
Nessov LA (1987) On some Mesozoic turtles of the Soviet union,
Mongolia and China, with comments on systematics. Studia
Geologica Salmaticensia. Stud Palaeocheloniol 2:87–102
Nessov LA (1995) On some Mesozoic turtles of the Fergana Depression
(Kyrgyzstan) and Dzhungar Alatau Ridge (Kazakhstan). Russ J
Herpetol 2:134–141
Nessov LA, Khosatzky LI (1973) Early Cretaceous turtles from
southeastern Fergana (in Russian). Problems in herpetology: Proc
3rd All-union Herpetological Conf. Zoological Institute of the
Academy of Sciences USSR, Leningrad, pp 132-133
Nessov LA, Khosatzky LI (1977) Freshwater turtle from the Early
Cretaceous of Fergana. Ezhegodnik Vsesoyuznogo Paleontologicheskogo Obshch 20:248–262
Nessov LA, Khosatzky LI (1981) Early Cretaceous turtles of Transbaikal (in Russian). In: Borkin LJ (ed) Herpetological research in
Siberia and the Far East.. Zoological Institute of the Academy of
Sciences USSR, Leningrad, pp 74-78
Parham JF, Hutchison JH (2003) A new eucryptodiran turtle from the
Late Cretaceous of North America (Dinosaur Provincial Park,
Alberta, Canada). J Vertebr Paleontol 23:783–798
Peng J-H, Brinkman DB (1993) New material of Xinjiangchelys
(Reptilia: Testudines) from the Late Jurassic Qigu Formation
(Shishugou Group) of the Pingfengshan locality, Junggar Basin,
Xinjiang. Can J Earth Sci 30:2013–2026
Russell D (1993) The role of central Asia in dinosaurian biogeography. Can J Earth Sci 30:2002–2012
Sinithsenkova ND (2002) New Late Mesozoic mayflies from the SharTeeg locality, Mongolia (Insecta, Ephemerida=Ephemeroptera).
Paleontol Zh 3:43–48
Sonoda T, Hirayama R (2009) A new trionychoid turtle (Order
Testudines: Class Reptilia) from the Lower Cretaceous of Central
Japan. In: Abstr Gaffney Turtle Symp. Royal Tyrell Museum,
Drumheller, pp 169–170
Shuvalov VF, Chkhikvadze VM (1979) On stratigraphical and
systematical position of some freshwater turtles from new
cretaceous localities in Mongolia. The joint Soviet-Mongolian
paleontological expedition. Transactions 8:58–76
Sukhanov VB (1964) Subclass Testudinata, Testudinates (In Russian).
In: Orlov JA (ed) Fundamentals of palaeontology. Amphibians,
reptiles and birds. Nauka, Moscow, pp 354-438
Sukhanov VB (2000) Mesozoic turtles of Middle and Central Asia. In:
Benton MJ, Shishkin MA, Unwin DM, Kurochkin EN (eds) The
Age of Dinosaurs in Russia and Mongolia. Cambridge University
Press, Cambridge, pp 309–367
Sukhanov VB, Narmandakh P (1974) A new Early Cretaceous turtle
from the continental deposits of the Northern Gobi (in Russian)
Mesozoic and Cenozoic Faunas and Biostratigraphy of Mongolia. Trans Joint Sov Mongolian Paleontol Expedition 1:192–220
Sukhanov VB, Narmandakh P (2006) New taxa of Mesozoic turtles
from Mongolia. Fossil Turtle Res 1:119–127
Swisher CC, Wang Y, Wang X, Xu X, Wang Y (1999) Cretaceous age
for the feathered dinosaurs of Liaoning, China. Nature 400:58–61
Tong H, Buffetaut E, Suteethorn V (2002) Middle Jurassic turtles from
southern Thailand. Geol Mag 139:687–697
273
Tong H, Ji S-A, Ji Q (2004) Ordosemys (Testudines: Cryptodira) from the
Yixian Formation of Liaoning province, Northeastern China: New
specimens and systematic revision. Am Mus Novit 3438:1–20
Tong H, Suteethorn V, Claude J, Buffetaut E, Jintasakul P (2005) The
turtle fauna from the Khok Kruat Formation (Early Cretaceous)
of Thailand. In: Wannakao L, Youngme W, Srisuk K, Lertsirivorakul R (eds) Proc Int Conf Geology, Geotechnology and
Mineral Resources of Indochina (GEOINDO 2005). Khon Kaen
University, Khon Kaen, pp 610–614
Tong H, Buffetaut E, Suteethorn V (2006) Isanemys, a new adocid turtle
from the Sao Khua Formation (Early Cretaceous) of the Khorat
Plateau, northeastern Thailand. Russ J Herpetol 13 [Suppl]:128–137
Tong H, Claude J, Naksri W, Suteethorn V, Buffetaut E, Khansubha S,
Wongko K, Yuangdetkla P (2009a) Basilochelys macrobios n.
gen. and n. sp., a large cryptodiran turtle from the Phu Kradung
Formation (latest Jurassic-earliest Cretaceous) of the Khorat
Plateau, NE Thailand. Geol Soc Lond Spec Publ 315:153–173
Tong H, Claude J, Suteethorn V, Naksri W, Buffetaut E (2009b) Turtle
assemblages of the Khorat Group (Late Jurassic-Early Cretaceous)
of NE Thailand and their palaeobiogeographical significance. Geol
Soc Lond Spec Publ 315:141–152
Vincent SJ, Allen MB (2001) Sedimentary record of Mesozoic
intracontinental deformation in the eastern Junggar Basin,
northwest china: response to orogeny at the Asian margin. Geol
Soc Am Mem 194:341–360
Wang G (1988) Jurassic (in Chinese with English abstract). In: Lai J,
Wang J (eds) Atlas of the palaeogeography of Xinjiang. Xinjiang
People's Publishing House, Urumqi, pp 64–70
Wiman C (1930) Fossile Schildkröten aus China. Paleontol Sin C 6:1–56
Wings O, Joyce WG (2009) An exceptionally large Jurassic turtle
taphocoenosis from Xinjiang Autonomous province, China. J
Vertebr Paleontol 29, 3 (suppl.):202A
Ye HK (1965) New materials of fossil turtles of Inner Mongolia. Vert
PalAsiat 9:47–69
Ye X (1963) Fossil turtles of China. Palaeontol Sin 150:1–112
Ye X (1973) Chelonia fossils from Wuerho (in Chinese). Mem Inst
Vertebr Paleontol Paleoanthropol 11:8–12
Ye X (1986a) A Jurassic turtle from Junggar, Xinjiang. Vert PalAsiat
24:171–181
Ye X (1986b) New material of Plesiochelys radiplicatus with
preliminary discussion of related problems. Vert PalAsiat
24:269–273
Ye X (1994) Fossil and Recent Turtles of China. Science Press,
Beijing
Ye Y (1999) A new genus of Sinemydidae from the Late Jurassic of
Neijiang, Sichuan. Vert PalAsiat 37:81–87
Ye Y, Pi X (1997) A new genus of Chengyuchelyidae from Dashanpu,
Zigong Sichuan. Vert PalAsiat 35:182–188
Young CC, Chow MC (1953) New fossil reptiles from Szechuan,
China. Acta Sci Sin 2:216–229
Zangerl R (1969) The turtle shell. In: Gans C, Bellairs AdA, Parsons TS
(eds) Biology of the Reptilia. Academic Press, London, pp 311–339
Zhou Z, Dean WT (1996) Phanerozoic geology of Northwest China.
Science Press, Beijing