OJG  Vol.9 No.10 , September 2019
Vitakrisaurus saraiki Theropod from South Asia
ABSTRACT
Vitakrisaurus saraiki abelisauroid theropod dinosaurs reported from Pakistan and extended distribution into India. Vitakrisaurus saraiki is medium to large sized theropod which is represented by associated vertebral and limb elements and especially hand elements. Out of 14 small to large bodied theropods from Indo-Pakistan subcontinent, only less than half of these are restricted to some common elements. Vitakrisaurus saraiki theropod of Pakistan is based on associated vertebral and limb elements especially hand including articulated carpals, metacarpals, phalanges and claws which are significant for Gondwanan paleobiogeographic link, comparisons and systematic.

1. Introduction

Two theropod dinosaurs were known from Pakistan. Vitakrisaurus saraiki is a medium sized theropod, which is significant for systematic and comparisons.

2. Vitakrisaurus saraiki Medium Sized Theropod of South Asia

Systematic paleontology of Vitakrisaurus saraiki is as follows: Dinosauria, Saurischia, Theropoda, Abelisauroidea, Vitakrisauridae [1] , Vitakrisaurus [1] , Vitakrisaurus saraiki [1] (Figure 1). Holotype and lectotype specimens were collected from the mid Bor 2 locality and referred specimens (Figure 1) were collected from the Shalghara 3 locality found in the uppermost Maastrichtian (67 - 66 Ma ago) Vitakri Lameta Formation of the Fort Munro Group, Barkhan district, Balochistan, Sulaiman or middle Indus basin, central Pakistan. Genus Vitakrisaurus honors the Vitakri host locality; saurus means lizard. Species name is in honor of the Saraiki language of locals of Sulaiman Range. These fossils are

Figure 1. Vitakrisaurus saraiki theropod fossils. Row 1, Map of Pakistan (black circle) show mid Bor 2 type locality, holotypic hand/manus. Row 2, lectotypic vertebral and limb fossils from mid Bor 2. Row 3, referred fossils from Pakistan (p 1 - 3) and India (p 4). Each black digit is 1 cm.

hosted in the Quetta museum of Geological Survey of Pakistan. Amphicoelous caudal vertebra with two chevrons from India [2] was referred to Vitakrisaurus saraiki.

2.1. Diagnosis of Vitakrisaurus saraiki Theropod from South Asia

Vitakrisaurus saraiki has circular elongated cylinder type dorsal centrum jointed on all dorsal length with neural arch (while dorsal centra of Vitakridrinda is rectangular and elongated while the dorsal centrum of Rajasaurus is tall); Vitakrisaurus has transverse process on upper part of caudal centrum and extends into neural arch like Rajasaurus while Vitakridrinda has oval shaped transverse process which did not contact with neural arch and located on upper part of posterior articular ring on anterior caudal centrum. Neural arch on anterior caudal is forwardly inserted while in Rajasaurus the neural arch covers all along the dorsal surface of centrum. Vitakrisaurus did not have ventral keel in dorsal and caudal centra while Rajasaurus and Rahiolisaurus had ventral keel. Vitakrisaurus neural canal is dorsoventrally compressed while Rajasaurus it is circular shaped; Vitakrisaurus has well developed chevron facets in anterior/mid caudals while Rajasaurus has no chevron facets. Vitakrisaurus anterior and midcaudal vertebrae have posterior yard on posterior uncover part of dorsal aspect of centrum surrounded by laterally and posteriorly thin boundary wall while this yard is not found in Rajasaurus thick bones of manus/hand; Metacarpal I is short and thick, metacarpal II and metacarpal III are thick, long and subequal; manual phalanges are thick; and manual ungual/claw I is thick and slightly recurved downward.

2.2. Description of Vitakrisaurus saraiki Theropod from South Asia

Vitakrisaurus saraiki has dorsal centrum which is circular, amphicoelous, slightly waisted with lateral feeble fossa. Vitakridrinda has rectangular and elongated dorsal centrum, while Rajasaurus has tall dorsal centrum. The dorsal centrum in Vitakridrinda and Vitakrisaurus has no ventral keel. In Rajasaurus, Rahiolisaurus and Nhandumirim, a longitudinal keel is present on ventral surface of centrum. The dorsal centrum in Rajasaurus is spool-shaped, with its articular faces deeper than broad. Vitakrisaurus has circular elongated cylinder type dorsal centrum jointed on all dorsal length with neural arch. Vitakrisaurus has transverse process on upper part of caudal centrum and extended into neural arch as Rajasaurus, while Vitakridrinda has oval shaped transverse process, not contacted with neural arch and located on upper part of posterior articular ring on anterior caudal centrum. Neural arch on anterior caudal is forwardly inserted while in Rajasaurus the neural arch cover all along the dorsal surface of centrum. Vitakrisaurus have well developed chevron facets in anterior/mid caudals. Rajasaurus has no chevron facets. In Vitakrisaurus neural canal is dorsoventrally compressed, transversely oval shaped in anterior and middle caudal vertebrae. In Rajasaurus neural canal is circular shaped. In Vitakrisaurus anterior and midcaudal vertebrae have posterior yard on the posterior vacant/uncover part of dorsal aspect of centrum. This yard is surrounded laterally and posteriorly by thin boundary wall. Vitakrisaurus have leg bones with thin peripheral bone on the central hollow cavity. Vitakridrinda has thick peripheral bones on central hollow cavity. The hand/manus has three preserved digits. The metacarpal I is the smallest while Metacarpal II is largest and metacarpal III is relatively intermediate. The metacarpal I is expanded at proximal and distal ends, while in the middle constricted. The metacarpal II is the longest and also thickest. The metacarpal III is intermediate in length, thicker than metacarpal I and metacarpal II. The metacarpal I (7 mm wide, 21 mm long) is short and thick, metacarpal II and metacarpal III are thick, long and subequal. Manual phalanx I is thick and long while reducing length and increasing count from digit I to digit II and then to digit III. Manual ungual/claw I is thick and slightly recurved downward.

Cite this paper
Malkani, M. (2019) Vitakrisaurus saraiki Theropod from South Asia. Open Journal of Geology, 9, 643-645. doi: 10.4236/ojg.2019.910063.
References
[1]   Malkani, M.S. (2010) Updated Stratigraphy and Mineral Potential of Sulaiman (Middle Indus) Basin, Pakistan. Sindh University Research Journal (Science Series), 42, 39-66.

[2]   Huene, F.V. and Matley, C.A. (1933) Cretaceous Saurischia and Ornithischia of the Central Provinces of India. Paleontologia Indica, No. 21, 1-74.

 
 
Top