Fossil lizards from the Deccan intertrappean beds (latest Cretaceous / earliest Paleocene) of lower Narmada basin, Malwa Plateau, India

Abstract

We here report on the first lizard fossils from the Deccan intertrappean strata (latest Cretaceous/Palaeocene) exposed at Kesavi, District Dhar in the Malwa Plateau of lower Narmada Valley, central India. The material is only fragmentary, but tentatively three tooth morphotypes of non-acrodontan lizards can be identified. Besides these, two oblong osteoderms, resembling paramacellodid osteoderms, are described as Squamata indet. The 4th isolated tooth is questionably referred to Squamata. Although the intertrappean deposits of the Deccan volcanic province have been explored for over three decades, lizards are scarce and many aspects remain unclear. However, the tentative absence of agamids in Kesavi and other localities yielding pre-Eocene deposits (e.g., Naskal and Kisalpuri) appears to be interesting, because a high diversity of agamids has been reported from early Eocene localities of India. There is, in contrast, a total absence of non-acrodontan lizards. The contrast between pre-Eocene and Eocene localities seems to be puzzling in the context of India’s supposed physical isolation from Asia during this time. Only future researches can shed light on that. Although the material described here brings only limited new insight, it supports that non-acrodontan lizards were present in India during the latest Cretaceous/earliest Palaeocene.

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Historical Biology
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Fossil lizards from the Deccan intertrappean beds
(latest Cretaceous / earliest Paleocene) of lower
Narmada basin, Malwa Plateau, India
Ravi Yadav, Sunil Bajpai, A.S. Maurya & Andrej Čerňanský
To cite this article: Ravi Yadav, Sunil Bajpai, A.S. Maurya & Andrej Čerňanský (2022): Fossil
lizards from the Deccan intertrappean beds (latest Cretaceous / earliest Paleocene) of lower
Narmada basin, Malwa Plateau, India, Historical Biology, DOI: 10.1080/08912963.2022.2103693
To link to this article: https://doi.org/10.1080/08912963.2022.2103693
Published online: 24 Jul 2022.
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Fossil lizards from the Deccan intertrappean beds (latest Cretaceous / earliest
Paleocene) of lower Narmada basin, Malwa Plateau, India
Ravi Yadav
a
, Sunil Bajpai
a
, A.S. Maurya
a
and Andrej Čerňanský
b
a
Department of Earth Sciences, Indian Institute of Technology, Roorkee, India;
b
Department of Ecology, Laboratory of Evolutionary Biology, Faculty of
Natural Sciences, Comenius University in Bratislava, Mlynská dolina, Bratislava, Slovakia
ABSTRACT
We here report on the rst lizard fossils from the Deccan intertrappean strata (latest Cretaceous/Palaeocene)
exposed at Kesavi, District Dhar in the Malwa Plateau of lower Narmada Valley, central India. The material is only
fragmentary, but tentatively three tooth morphotypes of non-acrodontan lizards can be identied. Besides these,
two oblong osteoderms, resembling paramacellodid osteoderms, are described as Squamata indet. The 4
th
isolated tooth is questionably referred to Squamata. Although the intertrappean deposits of the Deccan volcanic
province have been explored for over three decades, lizards are scarce and many aspects remain unclear.
However, the tentative absence of agamids in Kesavi and other localities yielding pre-Eocene deposits (e.g.,
Naskal and Kisalpuri) appears to be interesting, because a high diversity of agamids has been reported from early
Eocene localities of India. There is, in contrast, a total absence of non-acrodontan lizards. The contrast between
pre-Eocene and Eocene localities seems to be puzzling in the context of India’s supposed physical isolation from
Asia during this time. Only future researches can shed light on that. Although the material described here brings
only limited new insight, it supports that non-acrodontan lizards were present in India during the latest
Cretaceous/earliest Palaeocene.
ARTICLE HISTORY
Received 6 May 2022
Revised 15 July 2022
Accepted 16 July 2022
KEYWORDS
Squamata; cretaceous;
palaeogene; asia; gondwana
Introduction
Lizards from the Late Cretaceous-Palaeogene of India are only occa-
sionally documented. This has led to a poor understanding of squamate
history in this biogeographically interesting area, especially in the
context of the India’s collision with Asia in the early Palaeogene
(Klootwijk et al. 1992; Ali and Aitchison 2008; Najman et al. 2010;
Hu et al. 2016; Chatterjee et al. 2017; An et al. 2021), which strongly
influenced the characteristics of modern ecosystems of the whole of
South Asia. One of the lizard clades with a better documented history in
the Indian subcontinent is Acrodonta. Agamids have been described
from the early Eocene (~54 Ma) of the Vastan Lignite Mine, Gujarat,
western India (Prasad and Bajpai 2008; Rana et al. 2013; see Kapur et al.
2022 for a discussion on age), where a high diversity of acrodontan
lizards was observed, including Tinosaurus indicus Prasad and Bajpai,
2008. Later, the dentary of this taxon was also described from
a neighbouring early Eocene lignite deposit at Tadkeshwar (Smith
et al. 2016). Acrodonta (including Agamidae and Chamaeleonidae;
sensu Estes et al. 1988) is an Old World clade today, although at least
one lineage (Tinosaurus) is also documented from the Eocene of North
America (Marsh 1872; Estes 1983; Smith 2006). The origin of agamids
is still debated and the centre of agamid origin is suggested to be either
in Gondwana or eastern Asia (Borsuk-Białynicka and Moody 1984;
Macey et al. 2000; Wagner et al. 2021). Except for the acrodonts, no
other lizard clades are known from the early Eocene of India.
The diversity of agamids and the absence of non-acrodontan lizards
in India were suggested as tentative support for the Out-of-India
hypothesis for agamids (Prasad and Bajpai 2008; Rana et al. 2013).
The Out-of-India hypothesis was originally proposed by Krause and
Maas (1990) who hypothesised that several faunal and floral groups
that occur in Asia today originated on the isolated Indian subcontinent
and later dispersed to the northern landmasses as a consequence of
collision between India and Asia. In recent years, the Out-of-India
hypothesis has received support from fossil data on several groups
including mammals and frogs (see Bajpai 2009; Chatterjee et al.
2017). The presence of Tinosaurus (Prasad and Bajpai 2008; Smith et
al. 2016) in the Eocene of India is particularly interesting (note, how-
ever, that the problem of ‘Tinosaurus’ is that tricuspid teeth of a similar
form are probably present in some 200 living species of Agamidae,
more precisely in members of Draconinae and Leiolepis Cuvier, 1829;
see Smith et al. 2011). Tinosaurus appears to be globally widespread
during the Palaeogene, being also documented from the Eocene of
North America (see above), and from the earliest Eocene of Europe
(~56 Ma; Tinosaurus europeocaenus Augé and Smith, 1997). Among
other records, Tinosaurus postermus was described based on a fragment
of the left dentary from the latest Palaeocene/earliest Eocene of
Kazachstan (Averianov 2001), T. doumuensis from the middle
Palaeocene of China (Hou 1974, see also Dong et al. 2016), and
T. lushihensis Dong, 1965 and T. yuanquensis Li, 1991 from the
Eocene. Gilmore (1943) described the right dentary fragment from
the middle Eocene of Shara Murun area as a new species, T. asiaticus.
Later, a new generic name – Pseudotinosaurus – was erected for this
material by Alifanov (1991). This taxon most likely survived in
Mongolia till the Oligocene (Čerňanský and Augé 2019). However,
some of these taxa are represented solely by incomplete dentary frag-
ments whose allocation to Tinosaurus is based primarily on the basis of
tricuspid, acrodont cheek teeth and geological age (Estes 1983).
According to Smith (2011) the polyphyly of ‘Tinosaurus’ cannot be
excluded (see also Smith et al. 2011) and it seems to be a wastebin taxon
(Estes 1983; Smith et al. 2011).
Although the Deccan intertrappean deposits across the entire
Deccan volcanic province of peninsular India have been
explored for microvertebrates for over three decades,
CONTACT Andrej Čerňanský cernansky.paleontology@gmail.com Department of Ecology, Laboratory of Evolutionary Biology, Faculty of Natural Sciences,
Comenius University in Bratislava, Mlynská dolina 84215, Bratislava, Slovakia
HISTORICAL BIOLOGY
https://doi.org/10.1080/08912963.2022.2103693
© 2022 Informa UK Limited, trading as Taylor & Francis Group
Published online 24 Jul 2022

microvertebrates except fish are very rare. However, continental
vertebrate faunas of India from the Late Cretaceous/earliest
Palaeogene are crucial, because they document important infor-
mation on the paleobiodiversity and evolution of animals and
the palaeobiogeography of the Indian plate during its northward
journey (Chatterjee et al. 2017). Previously, isolated vertebrae
referred to an anguid lizard have been described from the
Deccan intertrappean beds of Naskal in south-central India
(Prasad and Rage 1995), a locality which is considered to be
latest Cretaceous or earliest Palaeocene in age (Wilson Mantilla
et al. 2022). The Naskal material also includes two badly pre-
served dentaries of indeterminate lizards with pleurodont denti-
tion, but without preserved teeth (Prasad and Rage 1995). Fossil
eggshells of gekkotan lizards have also been described from the
Deccan intertrappean deposits of Kutch, western India (Bajpai
et al. 1998). In Nagpur and Rangapur, interestingly, a relatively
high diversity of lizards was reported by Rana (2005): Litakis
sp., Pristiguana sp., Iguanidae indet., Agama sp., ? Contogenys
sp., Eumeces sp. and Exostinus estesai Rana, 2005. Note, how-
ever, that the identifications of Rana (2005) have been ques-
tioned by several authors (Prasad 2012; Rage et al. 2020).
Previously, an indeterminate ‘scincomorph’ was described
from Nagpur by Gayet et al. (1984). Recently, Rage et al.
(2020) described squamates from the Maastrichtian intertrap-
pean beds of Kisalpuri and Kelapur. Lizard material from these
localities consists of several indeterminate taxa, also including
possible ‘scincomorphs’.
Here, we describe a small collection of lizard fossils recently
collected from the Deccan intertrappean locality of latest
Cretaceous/early Palaeocene age in District Dhar, Madhya
Pradesh, in the Narmada basin of the Deccan Malwa Plateau,
west-central India. Although the material is fragmentary, it
shows the presence of several non-acrodont lizard groups.
Acrodonts, being so diverse in the early Eocene, are surprisingly
not recorded so far from Kesavi or any other Deccan intertrap-
pean locality in peninsular India, except for the questionable
assignment of the fragments from Rangapur to agamids by
Rana (2005, see Discussion).
Institutional Abbreviations: IITR – Indian Institute of
Technology, Roorkee, India.
Material and methods
The 90–100 kg samples were screenwashed using a standard pro-
cedure of soaking the raw sample overnight in a 1:3 ratio of H
2
0 and
H
2
0
2
, thereafter screening the material through various size sieves
(ASTM). The residue material was dried at a temperature below
50°C in an oven, and then sorted and studied using a binocular
microscope. The specimens were photographed at the SEM Lab of
IIT Roorkee. The image processing program ImageJ (Schneider
et al. 2012) was used for measurements. The fossils described herein
(Figures 3–5) are housed in the Palaeontology lab of the
Department of Earth Sciences, IITR, with the designation IITR/
VPL/INT-K/2022/ST. The terminology for teeth follows Richter
(1994) and Kosma (2004; see Figure 3m).
Geological setting
The fossil site at Kesavi (Figure 1; the coordinates of the sample
location are 22°28ʹ52.08”N and 75° 7ʹ22.69”E) exposes a Deccan
intertrappean section located in the lower Narmada Basin (intra-
cratonic rift basin), an ENE-WSW trending basin which is part of
the Malwa Plateau of west-central India. Exposed over an area of ~
80,000 km
2
, the Malwa Plateau forms the northern subprovince of
the Deccan Volcanic Province (Kale et al. 2019). The Malwa Plateau
is a relatively poorly studied region of the Deccan Volcanic
Province. With a maximum thickness of 500 m, the volcanic suc-
cession in the Malwa subprovince (Malwa Group) is divisible into
eight formations based on flow morphology (Rao et al. 1985; sum-
marised in Kale et al. 2019), and five formations based on geochem-
ical parameters, namely, the Narmada, Manpur, Mhow, Satpura,
and Singachori formations, in ascending order (summarised in
Eddy et al. 2020). The Malwa flows, considered by some to be the
oldest Deccan lava flows (Kale et al. 2019), possibly resulted from an
independent eruptive centre with the earliest eruptions being older
than, and the later activity partly synchronous with, the much
thicker and geochemically similar sequences of the Western Ghats
(Cox and Hawkesworth 1985).
The pre-Deccan Cretaceous stratigraphy (‘Bagh Beds’) under-
lying the Deccan volcano-sedimentary sequence of the Narmada
basin of Malwa Plateau has been extensively studied. The first
Figure 1. Geological map of Bagh area (a), Dhar district, Madhya Pradesh (modified after Jaitly and Ajane 2013), (b) location map of the study area.
2R. YADAV ET AL.

description of this marine sedimentary sequence dates back to
Blanford (1869) who recognised four lithologic units of the Late
Cretaceous Bagh Beds, namely, the Nimar Sandstone, Nodular
Limestone, Deola-Chirakhan Marl and Coralline Limestone, in
ascending order. Most later workers followed this classification of
the Bagh Beds (= Bagh Group, Jaitly and Ajane 2013). Among
numerous previous contributions on lithostratigraphy, fossils and
age of the Bagh Beds, mention may be made of Bose (1884), Rode
and Chiplonkar (1935), Roy Chowdhury and Sastri (1962),
Dassarma and Sinha (1975), Chiplonkar and Ghare (1976), Guha
(1976), Tripathi (2006), Jaitly and Ajane (2013) and Ruidas et al.
(2018). The Bagh Beds are overlain by the latest Cretaceous Lameta
Group, which, in turn, is succeeded by the Deccan Traps volcanic
flows, interbedded with intertrappean beds. The intertrappean
locality that yielded the material described herein (Figure 1) is
exposed on Dhar-Jeerabad road (State Highway-38) about
0.65 km west of Kesavi village, Dhar District, Madhya Pradesh.
Lithologically, the section exposes the lower Deccan lava flow, red
bole, paleosol, pinkish silty mudstone, greenish mudstone and the
upper Deccan lava flow, in ascending order (Figure 2). Microfossils
found associated with the lizard material described here include
common intertrappean freshwater fishes (Lepisosteus, osteoglos-
sids), ostracods (Zonocypris, Frambocythere, Gomphocyhere,
Limnocythere, Stenocypris, Cypria) and molluscs. Similar microfos-
sil assemblages (but not including lizards), considered by the
authors that described them to be of Upper Cretaceous age, have
been described from two other intertrappean localities (Manawar,
Gujri) of Dhar District, in the lower Narmada Valley (Kapur et al.
2019; Kshetrimayum et al. 2021).
The age of the Deccan basaltic flows was considered to be early
Eocene by earlier workers (e.g., Hislop 1860; Sahni 1934; Hora
1938; Bhalla 1974). During the past four decades or so, based
Figure 2. Lithology (a) with field photographs of studied intertrappean locality. (b) Photograph with a panoramic view of sample location, (c) photograph with a close view
of sample location.
HISTORICAL BIOLOGY 3

mainly on radiometric and magnetostratigraphic data, the age of
the Deccan lavas was re-assessed as latest Cretaceous-early
Palaeocene between 67 and 63 Ma, with bulk of the Deccan erup-
tions occurring in a short period of less than one million years (e.g.,
Courtillot et al. 1986; Vandamme et al. 1991; Chenet et al. 2007).
Palaeontological data from the Deccan intertrappeans currently
favour either a Late Cretaceous (Maastrichtian) or an early
Palaeocene age, broadly in agreement with the geochronological
and magnetostratigraphic constraints (Sahni and Bajpai 1988;
Bajpai and Prasad 2000; Keller et al. 2009; Wilson Mantilla et al.
2022).
Geochronologic data (
40
Ar-
39
Ar) from the Malwa Plateau sug-
gest an age of 67.12 ± 0.44 Ma for the initiation of volcanic activity
(Schöbel et al. 2014), and more recent constraints from U-Pb zircon
ages (Eddy et al. 2020) suggest a total duration of about 1.3 Ma
between 0.6 and 1.9 Ma during the magnetochrons C30n and C29r.
Magnetostratigraphic data on Malwa flows indicate two reversals
(N-R-N), with most workers correlating this reversal sequence with
C30n-C29r-C20n (Bhalla and GVSP 1974; Pal and Bhimasankaram
1976; Rao and Bhalla 1981; Khadri et al. 1999; Khadri 2003; Schöbel
et al. 2014). The exact polarity of lava flows stratigraphically adja-
cent to the Kesavi intertrappean deposit is not known, but the
~400 m altitude at this location (included in the site group sg6 of
Profile C-C’ of Schöbel et al. 2014) makes it likely that these inter-
trappean beds are close to the transition from normal to reverse
polarity (? C30n-C29r) and also lie close to the boundary of two
basal, geochemically defined basalt units, the Narmada and Manpur
formations (see Eddy et al. 2020). Lithostratigraphically, the Kesavi
intertrappean beds are included in the Kalisindh Formation of the
Malwa Group (GSI 2001). The stratigraphic position of the Kesavi
intertrappeans relative to two other intertrappean deposits in
District Dhar (Manawar and Gujri) is unclear.
Based on the foregoing account, our best current assessment is
that the age of the present intertrappean locality is either latest
Cretaceous (Maastrichtian) or earliest Palaeocene. Available resolu-
tion does not allow further refinement of the age of the Kesavi
section.
Systematic palaeontology
Squamata Oppel 1811
Squamata tooth morphotype 1
Figure 3(a-e)
Material, locality and horizon -one isolated tooth IITR/VPL/
INT-K/2022/ST-01; Kesavi, District Dhar, Madhya Pradesh,
Deccan intertrappean bed; late Cretaceous/early Palaeocene.
Description
Only the tooth crown is preserved (Figure 3a-e). The lingual surface
of the tooth is concave, being curved inward, whereas the labial one
is convex. In the medial view, the tooth crown is transversely
bicuspid. It has a larger, somewhat rounded labial edge (thus, the
overall appearance is blunt relative to other tooth morphotypes
described here), forming a labial cusp, and a smaller, sharper lingual
cusp. The latter is well defined and located at a moderate distance
from the labial one rather than being in the immediate vicinity. The
carina intercuspidalis connects them. Both cusps are distally dis-
placed. The lingual aspect of the crown is bordered by the culmen
lateris anterior and culmen lateris posterior. The lingual cusp is
bordered by well-visible striae dominans anterior and posterior.
Both mentioned striae diverge gradually further in the direction
of the tooth neck. Thus, the region that they bound is wide and
possesses around five faint apicobasal striae of low relief (pars
furcata sensu Richter 1994). The apicobasal striae run almost par-
allel in dorsoventral direction. The labial aspect of the crown is
smooth.
Squamata tooth morphotype 2
Figure 3(f-j)
Material, locality and horizon -one isolated tooth IITR/VPL/
INT-K/2022/ST-02; Kesavi, District Dhar, Madhya Pradesh,
Deccan intertrappean bed; late Cretaceous/early Palaeocene.
Description
Only the tooth crown is preserved (Figure 3f-j). In the medial view,
the crown can be divided into two portions: the dominant distal
portion, forming the dorsal apex, and the mesially expanded por-
tion. The distal portion is triangular and very slightly curved dis-
tally. This portion is transversely bicuspid, having a larger, labial
edge, forming a labial cusp, and a smaller, lingually located lingual
cusp. Both are sharp, but note that the lingual cusp is weaker than in
the morphotype 1. The lingual cusp is bordered by the striae
dominans anterior and posterior. They are almost parallel. Thus,
the area inside of the region defined by them is narrow (in contrast
to the wide region in morphotypes 1 and 3). This region gradually
diminishes further in the direction of the tooth neck. In the distal
area, between the culmen lateris posterior and the stria dominans
posterior, a shallow, but distinct depression is located.
The second portion of the crown is formed by a large, mesially
expanded section (crista mesialis sensu Richter 1994). The dorsal
margin between these two portions is angled (in an angle of 152
degree), but without a notch. This mesial portion appears to form
an accesory mesial cusp. The entire crown possesses apicobasal
striae – three diverging ones are located in the expanded anterior
portion. They incline mesially and distally in the ventral direction.
One additional apicobasal stria is located on the surface of the
lingual cusp. The labial surface of the crown is smooth.
Squamata tooth morphotype 3
Figure 3(k-l)
Material, locality and horizon – one isolated tooth IITR/VPL/
INT-K/2022/ST-03; Kesavi, District Dhar, Madhya Pradesh,
Deccan intertrappean bed; late Cretaceous/early Palaeocene.
Description
Only the tooth crown is preserved (Figure 3k-l). This morphotype
appears to form an intermediate condition between the morpho-
types 1 and 2, but also differs from both by the absence of apicobasal
striations (provided that the absence is not caused by abrasion or
corrosion, see Smith et al. 2021). The apex has a sharp and pointed
appearance, being triangular in shape. In the medial view, the tooth
crown is transversely bicuspid. It has a larger labial edge, forming
a labial cusp, and a smaller, medially located lingual cusp. Both are
sharp and the carina intercuspidalis connects them. The cristae
mesialis and distalis are almost the same length, so the apex is
only slightly distally displaced. These cristae of the labial cusp
expand slightly at the base of the main apex, forming a weak
bulge (the angulus mesialis and angulus distalis) on each side.
Further, the lingual aspect of the crown is bordered by the culmen
lateris anterior and culmen lateris posterior. Between the culmen
lateris posterior and the stria dominans posterior, a shallow
4R. YADAV ET AL.

depression is located. The depression is more pronounced at the
level of the angulus distalis, whereas this structure is weak on the
mesial side.
Squamata indet.
Figure 4
Material, locality and horizon -two body osteoderms IITR/VPL/
INT-K/2022/ST-04, 05; Kesavi, District Dhar, Madhya Pradesh,
Deccan intertrappean bed; late Cretaceous/early Palaeocene.
Description
Two body osteoderms are preserved (Figure 4). They are both of the
same type. The osteoderms are oblong, with their anteroposterior
length distinctly higher than the width. The external surface is
faintly sculptured. The ornamentation pattern consists of short
Figure 3. Squamata indet. from Kesavi. Tooth morphotype 1 (a-e), tooth morphotype 2 (f-j) and tooth morphotype 3 (k, l) plus general schematic terminology of tooth
crown (m; after Richter 1994, modified) in (a, f) labial, (b, g, k, m) lingual, (c, h, l) dorsal (or ventral), (d, i) anterolingual, and (e, j) posterolabial.
Figure 4. Squamata indet. from Kesavi. Fossil osteoderms in (a, b) external views.
HISTORICAL BIOLOGY 5

grooves, pits and ridges diverging from the central region. The
anterior gliding surface appears to be partly preserved only in
IITR/INT-K/2022/SO-04, although being unclear. It is short and
has no distinct border with the posterior ornamented section. In
this specimen, there is a very weakly developed (and hardly visible)
ridge located more-or-less in the centre.
? Squamata indet.
Figure 5.
Material, locality and horizon – one isolated tooth IITR/VPL/
INT-K/2022/AT-06; Kesavi, District Dhar, Madhya Pradesh,
Deccan intertrappean bed; late Cretaceous/early Palaeocene.
Description
The description is based on one isolated tooth (Figure 4). The tooth
is robust and conical. It is curved distally and slightly curved
medially. The tooth is mediolaterally compressed. The tooth base
is mesiodistally broad, whereas its tip is pointed. The mesial and
distal cutting edges are well developed. The crown lacks striations.
Discussion
Taxonomic allocation and comparison
The material described here is extremely fragmentary and consists
of only four isolated teeth and two osteoderms. Nonetheless, the
material forms an evidence of the occurrence of non-acrodontan
lizards in the Kesavi locality. Unfortunately, the recovered tooth
crowns are too generalised to justify allocating them to particular
clades without doubts. Our knowledge of lizard tooth crown
variation and evolution is still very incomplete. Moreover,
although differences clearly exist among the morphotypes 1–3,
the fragmentary nature of this record does not provide enough
support to fully exclude the possibility of individual and/or onto-
genetic variation. It cannot be also excluded that the different
morphology might be a result of a different position along the
tooth row in jaws as well. For all these reasons, we discuss in the
following some of the taxa that appear to have the greatest resem-
blance to the material described here. The material which is
referred to three tooth morphotypes clearly represents lizards.
Between the culmina, a pattern of striations can be observed on
the lingual surface of the tooth crown (except of the morphotype
3, note that it remains unclear whether the absence of striations in
IITR/VPL/INT-K/2022/ST-03 might be diagnostic or it is caused
only by taphonomic or digestive tooth corrosion). This condition
is observed in Scincoidea (see, e.g., Kosma 2004), which comprises
extant Cordyliformes plus Scincidae and their fossil relatives
Paramacellodidae, among others (Evans and Chure 1998;
Gauthier et al. 2012). We interpret the structures converging at
the cuspis lingualis in our specimens as striae dominans (seen in
paramacellodids, Richter 1994; Kosma 2004) rather than as cristae
lingualis (seen in scincids and lacertids; Kosma 2004). On the
other hand, several tooth crown features that are observed in
scincids and lacertids, and usually not in paramacellodids, are
present, such as the mesial accessory cusp in morphotype 2. This
feature deserves a comment. Paramacellodids, such as
Paramacellodus and Becklesius hostetteri, often have chisel-
shaped, unicuspid tooth crowns, in contrast to the teeth from
Kesavi (see Kosma 2004). Thus, the problem for taxonomic allo-
cation is that the feature in morphotype 2 appears to be an
evidence against scincoid affinity. In this case, it might resemble,
e,g. Meyasaurus, which also has bicuspid teeth (Evans and
Barbadillo 1997; Bolet and Evans 2010). On the other hand, the
bicuspidity in this European Cretaceous taxon (Meyasaurus) is
much better developed, whereas Becklesius teeth (see Kosma
2004: plate XIV figs 1– 11) can have a strong shoulder that is part-
way to being a cusp (the mesial region can be somewhat expanded
in some teeth, similar to that in morphotype 2). Today, the
diversity of Scincoidea (e.g., Scincidae) in India is high: 74 species
are allocated to 21 genera Ablepharus, Asymblepharus, Barkudia,
Chalcides, Cryptoblepharus, Dasia, Emoia, Eumeces, Eurylepis,
Eutropis, Kaestlea, Lipinia, Ophiomorus, Riopa, Ristella, Scincella,
Sephopis, Sphenomorphus, Subdoluseps, Toenayar and
Tropidophorus (Uetz et al. 2022). Note, however, that the
Figure 5. ?Squamata indet. from Kesavi. Tooth in (a) labial, (b) lingual; (c) anterior, and (d) dorsal (or ventral) views.
6R. YADAV ET AL.

transversely bicuspid tooth crowns are also reported in euble-
pharid gekkotans (Sumida and Murphy 1987). In contrast to the
Kesavi specimens, the tooth apices of eublepharids have markedly
rounded (blunt) appearance. Moreover, the angulus medialis and
distalis are absent, for instance. In any case, we decided to allocate
our material only to Squamata indet.
Among living taxa, osteoderms are mainly found in scincoids
and anguimorphs, although also occasionally in gekkotans and in
the head of lacertids (Evans 2008; Gauthier et al. 2012; Čerňanský
and Syromyatnikova 2019; Williams et al. 2022). However, osteo-
derms are almost certainly a primitive feature that is suppressed in
some modern lineages. The rectangular osteoderms like those from
the Kesavi locality can be found in paramacellodids, a group of
small to medium-sized scincoids with a covering of rectangular
osteoderms. Although a similar type is also characteristic of anguids
(e.g., Čerňanský and Klembara 2017), the ornamentation type and
overall shape of these distinctly prolonged osteoderms fits better,
indeed, with paramacellodids (Estes 1983; Williams et al. 2022).
Moreover, the total lack of any convex tubercle morphology on the
external side are characters of paramacellodid osteoderms (Richter
et al. 2010). This allocation might be especially plausible if the
locality finally was Cretaceous, because based on current knowl-
edge, it seems that this group did not survive the Cretaceous/
Palaeogene boundary. Paramacellodid lizards are reported from
numerous Jurassic and Cretaceous localities around the world (see
Evans and Chure 1998; Evans 2003 and literature therein). Note,
however, that this is a mainly Laurasian group, although some finds
indicate its occasional Gondwanan occurrence, e.g., in Morocco
(Richter 1994) and South America (Bittencourt et al. 2020). If
correct, it suggests an origin prior to the break-up of Pangaea
(Evans 2003), so their occurrence in India cannot be fully excluded.
The isolated tooth IITR/VPL/INT-K/2022/AT-06 is only ques-
tionably placed in Squamata. The combination of the slightly
recurved tooth, being pointed and mediolaterally compressed
might resemble some representatives of Anguimorpha (although
this is not unique to this clade). Based on the preserved labial
portion, we could estimate a presence of subpleurodont implanta-
tion of the teeth in this animal. If so, it would support an allocation
of this material to Anguimorpha. Note, however, that such inter-
pretation needs to be made with caution. Due to a fragmentary
nature, other animal groups cannot be fully excluded – the enamel
may have been stripped off – as occurs, for example, when a tooth
passes through stomach acid. However, this would also mean that
any enamel structures – like striae or serrations – would be
removed. Then this could even be a small archosaur tooth.
Moreover, other animal groups (e.g., fish or mammals) cannot be
fully excluded as well. Today, Varanus and Ophisaurus (= Dopasia)
occur in India (Uetz et al. 2022). The fossils of Varanus are known
from many Miocene localities of the Indian subcontinent (see, e.g.
Rage et al. 2001; Kumar and Kad 2003; Čerňanský et al. 2022; Villa
and Delfino 2022).
Pre-Eocene vs. Eocene lizard-bearing localities in India: is there
a contrast?
Considering the age of the Kesavi intertrappean site, i.e., latest
Cretaceous or early Palaeocene, the tentative absence of agamids
at this site might be of considerable biogeographic interest when
seen in the context of India’s supposed physical isolation from Asia
during this time, as depicted in most plate tectonic models (see
Chatterjee et al. 2017 for a discussion). However, given the paucity
of the lizard specimens actually recovered, it has to be noted that the
material described here gives only very limited view on the lizard
paleodiversity in India at the time of the deposition of Kesavi
intertrappeans. Therefore, other alternatives for the current absence
of these lizards cannot be fully excluded. Interestingly, agamids
appear to be absent in Naskal as well (Prasad and Rage 1995;
a locality which is also considered to be latest Cretaceous or earliest
Palaeocene in age [Wilson Mantilla et al. 2022]). The same is true
for the localities such as Nagpur, Kisalpuri and Kelapur (see
Introduction and Rage et al. 2020: table 6.1 for the distribution of
fossil squamates in the Deccan intertrappean beds of India). One
potential exception might be the fragmentary material from
Rangapur reported by Rana (2005) as Agama sp. However, the
material consists of three dentary fragments with pleurodont denti-
tion and Rana (2005) stated that: ‘the posterior teeth are probably
acrodont’. In contrast with chamaeleonids, indeed, agamids retain
a trace of the primitive pleurodont condition (often in caniniform
anterior teeth), but only in the anterior region (Moody 1980).
Obviously, the allocation of such fragmentary material from
Rangapur is questionable and such attribution needs to be con-
firmed by additional well-preserved specimens.
With regard to Kesavi and Naskal, as previously mentioned,
several possible explanations for absence of agamids exist and
caution is therefore needed. We cannot fully exclude potential
taphonomic, sampling or environmental biases. So, one explanation
for the absence of agamids in the pre-Eocene deposits might be the
absence of suitable environments in the studied areas preferred by
these lizards and their potential presence in a currently unknown
locality of this age cannot be excluded. As previously stated, lizard
finds of this age in India are not numerous (Rage et al. 2020). Thus,
in general, the currently known fossils do not allow to test any
hypotheses with significant results yet apart from demonstrating
the presence of at least several clades of non-acrodontan squamates
in India prior to the Eocene. In this view, on the other hand, the
absence of non-acrodontan lizards in the currently known early
Eocene Indian localities remains puzzling as well – the deposits of
the lignite mines at Vastan (Prasad and Bajpai 2008; Rana et al.
2013) and Tadkeshwar (Smith et al. 2016), both dated to the early
Eocene, yield rich materials of agamids, but no other lizard clades.
In view of the spatial distribution of Tinosaurus (although this
taxon is problematic, see Introduction) and the fact that it is
potentially known from older localities in Asia (Averianov 2001;
Hou 1974, see also Dong et al. 2016), it seems more likely that at
least this lineage might be a newcomer in India rather than origi-
nating there. It probably dispersed in India from Eurasia around the
time of India-Asia collision, at or prior to the Palaeocene-Eocene
boundary (~56 Ma). This scenario would also match the suggested
dispersal of many mammals out of/in to this island (Kapur et al.
2022). The existing database on the rich early Ypresian vertebrate
faunas from the lignite mines of Gujarat (where Tinosaurus was also
found) shows the presence of several taxa of European and Asian
affinities (Kapur and Bajpai 2015; Smith et al. 2016; Das et al. 2021),
together with some relict taxa of Gondwanan affinity, i.e., from the
time period before the India-Asia collision (e.g., Kapur et al. 2017).
Many aspects about paleobiodiversity of squamates in India
remain unclear. Future researches on Late Cretaceous and early
Palaeogene localities in India and neighbouring regions of Asia are
therefore crucial to better understand the role of this subcontinent
in the overall evolutionary history of lizards.
Acknowledgments
The material described in this paper is part of the doctoral work of R.Y. being
funded by IIT Roorkee. We are greatly indebted to Dr. K. T. Smith (Senckenberg
Research Institute) for English text corrections and to Prof. Susan Evans
(University College London) for helpful advice. We acknowledge the editor
HISTORICAL BIOLOGY 7

Dr. Gareth Dyke, as well as Dr. M. Hutchinson (South Australian Museum) and
two anonymous reviewers for their comments and suggested revisions of the
manuscript.
Disclosure statement
No potential conflict of interest was reported by the authors.
Funding
This work was supported by the Scientific Grant Agency of the Ministry of
Education of Slovak Republic and Slovak Academy of Sciences, Grant Nr. 1/
0191/21 (A. Č). S.B. would like to acknowledge support from IIT Roorkee as part
of his Institute Chair Professorship.
ORCID
Andrej Čerňanský http://orcid.org/0000-0002-1314-026X
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