Pakisaurus balochistani (Poripuchia, Slender Titanosauria, Sauropoda) Associated Skeletons Found from the Latest Maastrichtian Vitakri Formation of Pakistan and Referred Fossils from India; Filling of Important Missing Links of Isisaurus colberti Titanosaur Found from Pakistan

Recently two slender and medium to large sized titanosaur taxa like Pakisaurus balochistani and Isisaurus colberti of pakisaurids Poripuch along with small sized stocky Saraikimasoom and medium sized stocky Gspsaurus of gspsaurids Poripuch have been recognized from Indo-Pakistan subcontinent. The diagnosis and description of Pakisaurus balochistani and some missing elements of Isisaurus colberti discovered from Pakistan are added here for understanding of possible fuller anatomy of slender titanosaurs. Further so far no any research information regarding the comparison of titanosaurs of India and Pakistan is available. Here present research provides the comparison between titanosaurs recognized from Pakistan and India.

These Indian fossils are referred due to possible similarity with caudal vertebra (tall and the dorsal and ventral mid caudal width ratio 1) and flattened and transversely thin and narrow bone tibia and transversely narrow distal scapula.
Braincase referred due to finding large sized and different than Gspsaurus and Saraikimasoom and also suggested by a few previous researchers. This materials from India referred to Pakisaurus balochistani due to tall midcaudal with ratio of mid caudal width above and below is about 1 i.e. in ventral view the dorsal width are not clearly observed [24]. The Pakisaurus named after the host country Pakistan and species P. balochistani named after the Balochistan province, Pakistan collected from the Latest Cretaceous (latest Maastrichtian; 67 -66 Ma) Vitakri Formation of Fort Munro Group [14] from Pakistan [3] [4] [9] and Lameta Formation from India. The Pab Formation was divided into lower member Dhaola, middle member Kali and upper member Vitakri [3]. Later on the Vitakri Formation was established by [14] which include the meandering river deposits as sandstone units alternated by two overbank red, green and mottled coloured mud units. Two mud units of the Vitakri Formation (which is the upper part of previous Pab Formation) are the host of these fossils. Most of these fossils found as surface finds as clusters on the shale units, however a few were excavated partially and a few were found as isolated. Vitakri Formation varies from 1 m to 35 m in thickness deposited by alluvial fresh water terrestrial deposits. In Sulaiman (middle Indus) basin where these bones are found so far, the Vitakri sediments consist of two red mud units (mostly red and maroon shale with subordinate green and khaki shale) of over bank deposits and two sandstone units (thin to thick bedded, grey to white muddy quartzose, not clean) of meandering river channel deposits. The lower red mud units-over bank deposits (4 -14 m), middle sandstone unit (3 -4 m), upper shale/mud unit (3 -11 m) and upper sandstone unit (4 -7 m) are found in the eastern Sulaiman foldbelt [3]. At places the shale units and the middle sandstone unit is covered by scree. The Vitakri Formation (Ziarat laterite) is 0.3 m to 2 m in the Ziarat and Sanjawi areas of Ziarat district [3] while it is 1m thick (laterite and carbonaceous shale just like of latest Cretaceous Kingri coal of Vitakri Formation in eastern Sulaiman Basin) exposed in the Sor Tangi section of Zhob district located between Musafar Pur to Mina [38] [39], as tectonic set up Sor Tangi is located at the western extremity in Laki anticline of eastern Kirthar (Sindh Province) is typically represented by red to brown colored sandstone and shale which has lower contact with white colored sandstone of Pab Formation, exposed in the thrusted core of Laki anticline [26]. The Sangiali and Khadro formations are found clearly only in type sections, in other places their finding and identifications are difficult. However the Rakhi Gaj Formation is well exposed in Sulaiman and western Kirthar basins while its coeval Bara Formation is well exposed in eastern Kirthar Pakistan is the best place for the study of KT mass extinction and latest archosaurs and other biotas from where the latest archosaurs (titanosaurian sauropod and theropod dinosaurs, mesoeucrocodiles) and other biotas became extinct and the existing of wide exposures of marine and non-marine KT or KPg boundary. The characters of the latest titanosaurs and other archosaurs and biotas, end Cretaceous their mass extinction, wide exposures of terrestrial and marine Cretaceous-Tertiary boundary/KT boundary or Cretaceous-Paleogene boundary K-Pg boundary and dispersal of Cenozoic biotas from Pakistan have attracted the world scientists. In the eastern surrounding areas of Balochistan, the south Punjab also host the Vitakri Formation (and its vertebrates) exposed in Rakhi Gaj area and Mian Ghundi anticline in the Khar Fort Munro area of Dera Ghazi Khan, and Chitri and Dragal-Maarri areas of Rajanpur district, south Punjab.
Reference [40] reported Orbitoides (Lepidorbitoides) minor from lower part of the unit (Pab and Mughalkot formation) in Rakhi Nala representing early Maestrichtian age. Reference [41] reported mixed benthonic-pelagic foraminifers of Maastrichtian age from type locality area of Pab Formation. Reference [42] reported Globotruncana aff. G. linnei, Lituola sp., Omphalocyclus macropora, Orbitella media, Orbitoides sp., Siderolites sp., from Moro area in Moro (=Pab) formation with Maestrichtian age. According to dinosaur and associated vertebrate fossils, stratigraphic position and previous work, the reference [43] considered the age of Vitakri Formation as latest Maastrichtian or latest Cretaceous (67 -66 Mya/Million years ago) [44]. The Lameta Formation from India (coeval of Vitakri Formation from Pakistan) is the host of latest Cretaceous vertebrates from India. Its age latest Maastrichtian (67 -66 Mya) is based on the microfossils, vertebrates, and the associated basal flows of the Deccan lavas [1] [45] [46].

Diagnosis of Pakisaurus balochistani
Pakisaurus balochistani is a large sized gracile bodied pakisaurid Poripuchia titanosaurian sauropod sharing with the Titanosauria as procoelous caudals, forward insertion of neural arches on caudals, vertebrae lacking hyposphene-hypantrum articulations, prominent olecranon process on ulna and neural spine single and not bifid. Pakisaurus balochistani shares with Poripuchia [4] [27] as procoelous all caudal vertebrae except first biconvex in some taxa (because in Poripuchia anterior, middle and distal caudals found are all procoelous, while in lithostrotian distal caudals are not procoelous). Pakisaurus balochistani sharing with the Pakisauridae (characters same as genus and species Pakisaurus balochistani) as straight and slightly recurved slender teeth which have almost same thickness (diameter) except tip (opposite of gspsaurids teeth which are conical and converge and taper on all sides from base to tip); ratio of mid transverse width above and below of mid caudal centrum is about 1 i.e. the ventral view of mid caudal centra are not compressed or slightly compressed; transversely (relatively) thin bone of proximal tibia; proximal tibia, anteroposteriorly twice wide than transverse width (in Gspsauridae stocky tibia anteroposteriorly 1 to 1.5 times than transverse width); distal tibia is anteroposteriorly more wider than transverse width (while in Gspsauridae distal stocky tibia is transversely more wide than anteroposterior width). Pakisauridae is the most inclusive clade of Titanosauria containing Pakisaurus balochistani and Isisaurus colberti but not Saraikimasoom vitakri and Gspsaurus pakistani.
Pakisaurus balochistani is characterized by long slender legs and tall tail; narrow, long and recurved teeth with constant thickness from base to tip (except tip) and slender indices more than 5 (while Gspsaurus and Saraikimasoom have moderate and small teeth respectively with gradually decreasing thickness from base to tip, and have rounded and pointed tips and slender indices vary from 3 - Extension of Procoely from anterior caudals to distal caudals-a discussion: Reference [49] mentioned "Procoely in anterior caudal vertebrae has traditionally been regarded as a derived titanosaur feature, with this convergently present in Mamenchisaurus and flagellicaudatans" [50]- [55]. However, mild procoely is present in the anterior caudal vertebrae of the basal titanosaur Andesaurus [56], as well as the somphospondylan Tastavinsaurus [57], and the non-titanosaurian Dongbeititan possesses strongly procoelous anterior caudal vertebrae [58]. Furthermore, a number of probable non-neosauropods also display  [33] and the tooth of Rapetosaurus krausei are also similar in nature [70]. So it also helped again to assign this tooth GSI 20,006 to Pakisaurus balochistani. The braincase GSI K27/497 ( Figure 5) along with left and right scapula and two right humeri was assigned to Jainosaurus (=Antarctosaurus) septentrionalis [35]. This braincase GSI K27/497 was referred to Pakisaurus balochistani [22] due to large size with D-shaped with ventrally convex condyle and distinguished ball of the condyle sharply defines from its narrower neck; Basal tubera breadth, narrower than occipital condyle; Occipital region of skull shape, flat and distally recurved; Paroccipital processes oriented transversely; Basal tubera are long process, diverging laterally with relatively lower angle (than its stocky cousin the Gspsaurus pakistani who have high angle basal tubera); Basal tubera directed slightly backwards; From the large basal tubera the basipterygoid processes branch off; and Basipterygoid processes diverge somewhat anteriorly and much longer than the basal tubera but their ends are not preserved [35]. Vertebrae The axis centrum (Nand axis; 196/CRP/GSI/05 [36]) from India is being referred to Pakisaurus balochistani on the basis of cervical vertebral morphology and distinguishing from Gspsaurus axis (articulated atlas-axis from Pakistan [12] [21]). This Pakisaurus axis is taller than broad anteriorly and broad than tall posteriorly, relatively elongate, with its length more than twice its height and pneumatic or spongy [36]. More characters of Pakisaurus axis can be seen in [36] and Gspsaurus axis can be seen in [12] [21]. The other member of gspsaurids from Indo-Pakistan is the Saraikimasoom vitakri [22] [23] who is small in size while the axis proportions show its assignment to medium presacral remains is anticipated that the Nand axis pertains to a titanosaur with a high degree of external pneumatization apparent throughout the cervical series [36]. So the above statement of [36]) conveys that Nand axis is expected to belong to Pakisaurus balochistani pakisaurids the slender titanosaurs who have pneumatic presacral vertebra, matching of pleurocoel shape, proportion, etc and again different from gspsaurids axis.
The cervical vertebrae are broad, long and opisthocoelous ( Figure 1). The vertebrae represent the camellate/spongy/pneumatic texture and elongated lateral pleurocoel. The pleurocoel is thick anteriorly and relatively thin posteriorly. The neural spine seems to be undivided. The broken vertebrae represent the external and also internal spongy/pneumatic texture. Parapophyses are located on the anterior of pleurocoel of cervicodorsal vertebra. This cervicodorsal centra are broad (height is less than width) and relatively less longer than cervical. In general length is more than width. The centra are strongly opisthotic and have single rounded pleurocoel and ventral flat surface. The dorsal vertebrae are slightly broad, slightly long and opisthocoelous ( Figure 1). The dorsal centrum is relatively less broad and less long and higher than cervical vertebrae. The pleurocoel is single, relatively short and anteriorly slightly wider (dorsoventrally) than posteriorly. The broken vertebrae represent the external and also internal spongy/pneumatic texture. There is no hyposphene-hypantrum articulation. The proximal portion of dorsal rib is pneumatic. The coosified two sacral vertebrae are broad and pneumatic.
Anterior caudal centra have no pleurocoel. Anterior caudal transverse processes proximal depth, deep, extending from centrum to neural arch. Anterior caudal transverse processes shape, subcircular shaped extending to neural arch forming belt. Anterior and middle caudal centra, shape, quadrangular, groove ventrally, flat laterally and ventrally not reduced. Vertically oriented neural spine ( The slight and very feeble vertical groove on posterior ball of distal caudal centrum is reported from Lirainosaurus astibiae [47] from Spain Europe and U-shaped groove on posterior ball of distal caudal centrum Epachthosaurus sciutoi [48] from Patagonia, Argentina South America. The Pakisaurus referred caudal centrum (NHMUK R16481) collected by Matley 1930s from Chhota Simla India [16] has elemental dimension like length 14.9 cm, anterior face height 11.5 cm, anterior face width 10.3 cm, estimated posterior face height 10.5 cm and posterior face width 9.5 cm [16]. These measurements matches with caudal vertebra of Pakisaurus can be seen Table 1 of [9].
This caudal vertebra considered associated with some limb elements [16]. While this vertebra shows affinity to Pakisaurus balochistani and other associated limb elements from Chota Simla [16] [32] belong to Gspsaurus pakistani due to typi-cal tibia. According to [16] this caudal vertebra have a conical posterior convexity, a posteroventrally beveled anterior articular concavity, and a marked ventral hollow which is different than Isisaurus colberti. Gspsaurus and also Saraikimasoom mid caudal vertebrae show some ventral reduction and significant ventral reduction respectively which is not found in this Chota Simla vertebra. Its tallness, planar lateral surface and no ventral reduction revealed affinity to Pakisaurus balochistani.  Figure 2) is relatively thin and also seems to be spongy. Iliac preacetabular process shape triangular and thick plate. Further the posterior part of ilium (MSM-806-4; Figure 2) represents rod type projection. This rod type posterior projection of ilium may be the remnants of a sacral rib. This rod type projection is also found in the Lusotitan atalaiensis [47]. The lower Bor tibia is associated with humerus having anteriorly well exposed and well expanded radial condyle which is different than Isisaurus colberti. Further this tibia of Pakisaurus balochistani is different than the more robust and The Bruhathkayosaurus [71] was reported as carnosaur but these bones especially slender tibia may be referable to pakisaurid the slender and large sized titanosaurs. The Bruhathkayosaurus tibia is 2 meter long with proximal width 650 cm and distal end width 600 cm and shaft is 380 cm [71]. The 2 meter long and transversely thin tibia of Bruhathkayosaurus [71] matches close proportion to the Pakisaurids (Isisaurus and Pakisaurus). Further the very largest 2 meter unusual long and transversely thin tibia of Bruhathkayosaurus [71] shows its affinity to Pakisaurus because of larger caudal vertebrae of Pakisaurus balochistani than Isisaurus colberti. The ratio of anteroposterior width of distal end (600 cm) to anteroposterior width of proximal end (650 cm) is 0.92 of tibia of Bruhathkayosaurus, this ratio is close to Pakisaurus and also suggests the unusual long tibia assignment to Pakisaurus. The distal end of tibia is about one and half (1. There is a ridge in the base of medial scar, starting from dorsoposterior corner trending obliquely anteroventrally. The distal fibula is subcircular to suboval shape ( Figure 4). Fibular distal condyle size is expanded and not equal to mid shaft. The fibula K27/489 [35] from India assigned with Titanosaurus indicus materials show its assignment as Pakisaurus balochistani. Distal fibula laterally has a notch or keel type structure at the distal ends. Medially slight dorsoventrally elongated concavity is found. Fibula with inset anterior crest set off by ridge. Fibula, proximal tibial scar, seems to be well-marked and deepening anteriorly. The size of fibular distal condyle, expanded transversely, more than twice midshaft breadth.
It has no central concavity.

Filling of Missing Gaps in Isisaurus colberti
The Isisaurus colberti shares with Poripuchia because all the reported its caudal vertebrae especially distal caudals from India and Pakistan show procoely. The Isisaurus colberti shares with Pakisauridae (medium to large sized slender titanosaurs) the ratio of mid transverse width above and below of mid caudal centrum is about 1.00 i.e. the ventral view of mid caudal centra are not compressed or slightly compressed and slender flattened tibia with anteroposteriorly broad distal ends, while Gspsauridae is represented by ventrally reduced mid caudals and stocky tibia with transversely broad distal ends.
Isisaurus colberti is represented by one associated partial skeleton from India [25] and three associated partial skeletons from Pakistan. These three associated partial skeleton includes the holotypic caudal vertebrae of Sulaimanisaurus gingerichi [9] from south Kinwa 4; referred slender flattened tibia, fibula and metatarsal ( Figure 6) of Sulaimanisaurus gingerichi from Zubra peak 7; and slender humerus and femur ( Figure 6) of Sulaimanisaurus gingerichi from lower Sangiali 1. It is necessary to mention that the Sulaimanisaurus gingerichi fossils are referred to Isisaurus colberti due to more similarity and recent recognition of 4 taxa of titanosaurs out of fifteen named titanosaurs from Indo-Pakistan subcontinent. So now these three associations from Pakistan are being referred to Isisaurus colberti which have filled many significant missing gaps ( Figure 6  The distal humerus ( Figure 6) has no expanded and anteriorly exposed radial condyle like its holotypic humerus, and unlike other poripuch titanosaurs from Indo-Pakistan. The right femur has same size as the distal humerus and both found from same site of lower Sangiali 1, so believed associated.
The distal femur ( Figure 6) is slender and has triangular shaped small hollow cavity observed in the cross sectional view.
Fibula ( Figure 6) has medial crest trending dorsoposteriorly to anteroventrally and terminating at mid way. Further this fibula has no rugose parallel structures ( Figure 6) unlike the fibula of Pakisaurus balochistani (Figure 3). Metatarsal is thick subcircular shaft and convex shaped end.

Recognized four Titanosaur Taxa from Indo-Pakistan Subcontinent; Their Typical Key Elements and Comparison
The recent [20] [75]. The fossils reported by [35] show three titanosaurs while fourth titanosaur Isisaurus colberti was reported later in 1997 [25]. Reference [16] recognized two titanosaur taxa from Indo-Pakistan. The present work and other recent discoveries [21] [23] from Pakistan since 2000 to so far revealed at least four titanosaurs with four diverse cranial and postcranial fossils like skull and teeth, tibiae, humeri, femora, scapulae, caudal vertebrae and others. The major problem in considering only two titanosaur taxa is the referring of tetra diverse and diagnostic fossils collected from India and Pakistan so far. While this problem is solved, when [20] [21] [22] [23] [24] and present work revealed four recognized titanosaur taxa from Indo-Pakistan on diagnostic tetra diverse associated cranial and postcranial skeletons especially tibiae. Their typical key elements and comparison are being presented here.
Four typical key tibiae of Poripuch titanosaurs from Indo-Pakistan: Two types of slender, flattened, transversely compressed tibia (described above), and two types of stocky and transversely expanded tibia described by [21] [23] along with other bones resolved certainly the long standing controversy regarding the number of taxa of titanosaurs from Indo-Pakistan. Now it became certain by four types of tibia ( Figure 7) along with other associated cranial and postcranial Open Journal of Geology materials. The outer morphology, proportional measurement, shape and features of tibiae of recognized four taxa allow its distinction. Saraikimasoom has quite robust and stockiest (most expanded transversely and anteroposteriorly approaches their equal widths), proximal tibia with equal anteroposterior and transverse width (subsquare shaped femoral articular surface in proximal view) with subsquare to subcircular shaped mid shaft cross section (anteroposteriorly width of shaft may be about same or slightly more than transverse width), and quite robust transversely broad suboval to subrectangle shaped distal tibia ( Figure   7), Gspsaurus has robust and stocky (expanded anteriorly and transversely), proximal tibia (anteroposteriorly slightly long, asymmetric biconvex lense shaped femoral articular surface in proximal view) with oval shaped mid shaft cross section (anteroposteriorly width of shaft may be about or slightly more than twice transverse width), and quite robust transversely broad subrectangle shaped distal view of distal tibia (Figure 7), Isisaurus colberti has slender transversely compressed proximal tibia, with anteroposteriorly broad triangle shaped distal view of distal tibia (Figure 7), and Pakisaurus has quite slender flattened and transversely compressed proximal tibia with anteroposteriorly quite broad/more broader distal tibia than Isisaurus colberti (Figure 7). Jainosaurus (=Antarctosaurus) septentrionalis is based on braincase, vertebra and left and right scapula two left humeri and one or two weathered bones reported from Bara Simla India [35] which represents dual affinity and chimera nature, and further also no associated other materials.  [35] are also different with each other and may belong to two different taxa. The vertebra of Jainosaurus (=Antarctosaurus) septentrionalis [35] may be referable to Pakisaurus. The Chota Simla assemblages of Matley [32] were referred to Jainosaurus (=Antarctosaurus) septentrionalis [16]. Again the materials described by [16] have dual affinity. The vertebra described by [16] is referable to Pakisaurus due to tall, flat sided and ventrally not reduced. The associated limb elements described by [16]  condyle expanded or well divided especially radial condyle is expanded and exposed anteriorly and situated almost at the transverse centre. Third morphology of humerus [21] is moderate in size belongs to Gspsaurus pakistani, which represents prominent medial process of medial limb of proximal humerus is more extruded in the medial side (with possibly distal condyle expanded or well divided). Fourth morphology of humerus [23] is relatively small belongs to Saraikimasoom vitakri which represents distal humerus with expanded radial condyle exposed anteriorly but situated offset from centre. The deltopectoral crest is shifted medially shown in the Sangiali humeri of Saraikimasoom Vitakri and also like the Chota Simla humerus of Gspsaurus pakistani.
Five types of caudal vertebrae of titanosaurs from Indo-Pakistan: Five types of vertebrae especially caudal vertebrae [9] of poripuch titanosaurs were diagnosed from Indo-Pakistan subcontinent. First type, tall mid caudals with ratio of mid transverse width above and below of centrum is about 1 belong to Pakisaurus balochistani; slightly tall mid caudals with ratio of mid transverse width above and below of centrum is about 1.3 to 1.5, belong to Gspsaurus pakistani; squarish to broad mid caudals with ratio of mid transverse width above and below of centrum is about 1.5 to 2, belong to Saraikimasoom vitakri; squarish mid caudal with ratio of mid transverse width above and below of centrum is about 1, belong to Isisaurus colberti or Sulaimanisaurus gingerichi; squarish mid caud-

Associations and Partial Skeletons of Poripuchian Titanosaurs from the Latest Cretaceous Vitakri and Lameta Formations of Indo-Pakistan Subcontinent (South Asia)
The Cretaceous dinosaur fauna of Indo-Pakistan has remained poorly understood because of a lack of associated and articulated remains, proliferation of named species, and an incomplete understanding of the clades present [16]. Due to recent discoveries from Pakistan, the above problems are resolved. four taxa of titanosaurs based on the following associated partial skeletons. These associated skeletons provide a fuller understanding of its anatomy and phylogenetic affinities.
Pakisaurus balochistani is represented by two associated partial skeletons from Pakistan like the holotypic vertebral and appendicular elements [77] ( Figures 1-3) from Kinwa (the western site of South Kinwa) and its exemplar associated skeleton of vertebral and mostly appendicular elements (Figure 4) from lower Bor 2 locality. The Pakisaurus balochistani holotypic associated partial skeleton of south Kinwa includes the cervical, cervicodorsal, dorsal, sacral and caudal vertebrae, sternal, a pair of scapula (left and right scapula), right humerus, radius, a pair of ulna (left and right ulna), ilium, right femur, a pair of fibula (left and right fibula), manus/pes foot bones (Figures 1-3).
The other associated partial skeleton of Pakisaurus balochistani found from Isisaurus colberti is represented by one associated partial skeleton from India [25] and three associated partial skeletons from Pakistan (added here). Three associated partial skeleton includes the holotypic caudal vertebrae of Sulaimanisaurus gingerichi [9] from south Kinwa 4, slender flattened tibia, fibula and metatarsal ( Figure 6) (Figure 7) of Sulaimanisaurus gingerichi from Zubra peak 7 and slender humerus and femur ( Figure 6) of Sulaimanisaurus gingerichi from lower Sangiali 1. It is necessary to mention that the Sulaimanisaurus gingerichi fossils are referred to Isisaurus colberti due to recent recognition of 4 taxa of titanosaurs out of fifteen named titanosaurs from Indo-Pakistan subcontinent. So now these three associations from Pakistan are being referred to Isisaurus colberti which have filled many missing gaps ( Figure 6) of Isisaurus colberti for the understanding of fuller anatomical features.
Gspsaurus pakistani is represented by three associated partial skeletons from Pakistan and one associated partial skeleton from India [21]. First the Gspsaurus pakistani holotypic cranial, vertebral and appendicular skeleton from central Alam 19 which includes the partial skull with braincase, cervical, dorsal and caudal vertebrae, partial ilium or sternal, a pair of scapula (left and right scapula), radius, left femur, and a pair of tibia (left and right tibia). Second the asso-   [78] includes more than 10 teeth and a few cranial small bones, tall dorsal vertebra and a pair of femora (left and right femur) from Alam 19 type locality [78], and referred materials include possibly partial skeleton of tall dorsal vertebrae, subcircular caudal vertebra, whiplash elongated distal caudal centrum and metatarsals from Top Kinwa 16 [78], tall dorsal vertebra from Sangiali 1 [78], and anterior caudal vertebrae from Mari Bohri 15 [78]. Second large sized theropod Vitakrisaurus saraiki [79] is represented by holotypic skeleton [78] includes almost complete manus with articulated and associated its most of the elements, anterior and mid caudal vertebrae, proximal ulna, cross section of humerus and limb bones found from mid-Bor 2 type locality [78], and referred materials include subcircular cylindrical dorsal vertebra from Shalghara 3 locality of Vitakri dome area, Barkhan district, possibly leg bones [78] from Karkh area of Khuzdar district, Pakistan, and a caudal vertebra with two chevrons [35] [37] [78] from Bara Simla India. Medium to large sized mesoeucrocodile Induszalim bala [80] is represented by holotypic skeleton [78] includes snout/rostrum, rib, caudal vertebrae, proximal humerus and proximal ulna, metacarpals, ilium, femur, tibia articulated with fibula, and metatarsals found from mid Bor 2 type locality and referred materials include anterior snout with teeth, dentary ramus with 4 alveoli with partial teeth, jaw ramus with two teeth sandwiched by a diastema, anterior snout with articulated 2 teeth (one tooth on right and one on left jaw ramus) found from Shalghara 3, and dentary ramus with articulated four spaced teeth from Bor 2, and dorsal vertebra from Top Kinwa 16, Barkhan district, Balochistan and a partial rib/phalanges from south western vicinity of Khuzdar town, Balochistan. Medium to large sized mesoeucrocodile Pabwehshi pakistanensis [81] is represented by holotypic snout articulated with dentary found from Top Kinwa 16 and referred dentary symphysis from Shalghara 3. Medium to large sized mesoeucrocodile Sulaimanisuchus kinwai [82] is represented by holotypic dentary symphysis with articulated teeth and proximal humerus from south Kinwa 4 or 4s. Medium to large sized pterosaur Saraikisaurus minhui [78] is represented by holotypic beak or dentary with articulated 8 teeth (some teeth are overlapped) found from Top Kinwa 16, Barkhan District, Pakistan [78] and referred jaw with overlapped teeth [83] from Kotah, Rajasthan, India [78]. Further recently discovered basilosaurid, baluchithere rhinoceros, horses, sea cow, proboscidean, eucrocodile, pterosaurs, plesiosaur, fishes, invertebrates and wood fossils, and footprints and trackways were reported from Pakistan [27]. All these fossils from Pakistan and their significant localities are geoheritage and paleobioheritage and assets of Pakistan which needs their pro-

Conclusions
Due to lack of associated skeletons of slender and large titanosaurs from Indo-Pakistan (South Asia), this finding of holotypic associated skeleton from south Kinwa and referred associated skeleton from lower Bor, Balochistan, Pakistan is providing significant features of Pakisaurus balochistani a slender and large titanosaur from Indo-Pakistan subcontinent. There is also lack of cranial and associated postcranial remains of titanosaurs in Indo-Pakistan but this cranial, and associated postcranial remains of Pakisaurus balochistani slender and large titanosaur from Indo-Pakistan provides significant and distinct cranial and postcranial features for the comparison, evolutionary and phylogenetic studies of titanosaurs in the globe.
Isisaurus colberti which is based on associated postcranial skeletons has many important missing links. Among these some significant missing links especially hind limb elements, are partly filled and added here. This filling of missing gaps of Isisaurus colberti the slender titanosaur from Pakistan is unique gift and pro-vided the key elements especially slender flattened and transversely compressed tibia with key features for future phylogenetic studies.
So far no any comparison of Indo-Pakistan titanosaur fauna is made but here a comparison of cranial, vertebral, appendicular and limb elements of four recognized taxa of titanosaurs from Indo-Pakistan is presented. Recently the four recognized titanosaur taxa from Indo-Pakistan include the two slender titanosaurs like Pakisaurus and Isisaurus and two stocky titanosaurs like Gspsaurus and Saraikimasoom.
Fortunately the four typical key tibiae of four recognized titanosaur taxa associated with other elements were found from Pakistan. There was a long standing controversy and issue regarding the valid and coexisting titanosaur taxa in Indo-Pakistan subcontinent. Luckily the findings of four typical key tibiae (along with associated cranial and postcranial skeletons) discarded the hypothesis of two titanosaur taxa from Indo-Pakistan subcontinent and revealed two distinct slender poripuchian titanosaurs and two distinct stocky poripuchian titanosaurs from Indo-Pakistan subcontinent.
The extension of procoely into anterior and middle caudal vertebrae has been considered a feature of lithostrotian [51] [52] [53] [54] [55], while the extension of procoely into anterior and middle and posterior caudal vertebrae from Indo-Pakistan subcontinent has been considered a feature of Poripuchia [4] [27] titanosaurs. Poripuch is the Saraiki language word means full tail (with procoelous vertebrae). The Poripuchia titanosaurs consist of all procoelous caudals including the distal caudals also; however in some taxa especially stocky titanosaurs the first caudal is biconvex. In pakisaurids and gspsaurids all the caudal vertebrae found so far belong to anterior, middle and distal caudal vertebrae are procoelous (except first biconvex caudal). The Poripuchia is the most inclusive clade containing all caudal procoelous (except first biconvex caudal in few taxa).
The Poripuchia is the most inclusive clade containing Pakisaurus and Isisaurus of pakisaurids, and Gspsaurus and Saraikimasoom of gspsaurids the derived titanosaurs.
Further many cranial and postcranial associations of recognized two slender and two stocky titanosaurs from Pakistan and also India are presented and discussed. Pakisaurus balochistani slender titanosaur has two associations from south Kinwa and lower Bor in Pakistan, while Isisaurus colberti slender titanosaur has one holotypic association from Dangargaon India and three brief associations from Pakistan, which is the holotypic and exemplars of Sulaimanisaurus gingerichi, here being referred to Isisaurus colberti. Besides slender titanosaurs, the stocky titanosaurs are relatively more common in Pakistan and also have more associations of cranial and postcranial skeletons. Gspsaurus pakistani have three association from Pakistan like Alam, Top Kinwa, Mari Bohri and mid Bor of Pakistan and one association from the Chota (Chhota) Simla of India. Saraikimasoom vitakri have one holotypic snout (including articulated lower and upper jaws and complete teeth row) found from south Kinwa, and other three